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DES-3326
24-Port Fast Ethernet
Plus 2-Port Gigabit Module
Layer 3 Switch
User’s Guide
Second Edition (July 2002)
651ES3326025
Printed In Taiwan
RECYCLABLE
Wichtige Sicherheitshinweise
1. Bitte lesen Sie sich diese Hinweise sorgfältig durch.
2. Heben Sie diese Anleitung für den spätern Gebrauch auf.
3. Vor jedem Reinigen ist das Gerät vom Stromnetz zu trennen. Vervenden Sie keine Flüssig- oder Aerosolreiniger. Am besten dient ein angefeuchtetes Tuch zur Reinigung.
4. Um eine Beschädigung des Gerätes zu vermeiden sollten Sie nur Zubehörteile verwenden, die vom Hersteller zugelassen sind.
5. Das Gerät is vor Feuchtigkeit zu schützen.
6. Bei der Aufstellung des Gerätes ist auf sichern Stand zu achten. Ein Kippen oder Fallen könnte Verletzungen hervorrufen. Verwenden Sie nur sichere Standorte und beachten Sie die Aufstellhinweise des Herstellers.
7. Die Belüftungsöffnungen dienen zur Luftzirkulation die das Gerät vor Überhitzung schützt. Sorgen Sie dafür, daß diese Öffnungen nicht abgedeckt werden.
8. Beachten Sie beim Anschluß an das Stromnetz die Anschlußwerte.
9. Die Netzanschlußsteckdose muß aus Gründen der elektrischen Sicherheit einen Schutzleiterkontakt haben.
10. Verlegen Sie die Netzanschlußleitung so, daß niemand darüber fallen kann. Es sollete auch nichts auf der Leitung abgestellt werden.
11. Alle Hinweise und Warnungen die sich am Geräten befinden sind zu beachten.
12. Wird das Gerät über einen längeren Zeitraum nicht benutzt, sollten Sie es vom Stromnetz trennen. Somit wird im Falle einer Überspannung eine Beschädigung vermieden.
13. Durch die Lüftungsöffnungen dürfen niemals Gegenstände oder Flüssigkeiten in das Gerät gelangen. Dies könnte einen Brand bzw.
Elektrischen Schlag auslösen.
14. Öffnen Sie niemals das Gerät. Das Gerät darf aus Gründen der elektrischen Sicherheit nur von authorisiertem Servicepersonal geöffnet werden.
15. Wenn folgende Situationen auftreten ist das Gerät vom Stromnetz zu trennen und von einer qualifizierten Servicestelle zu überprüfen: a – Netzkabel oder Netzstecker sint beschädigt. b – Flüssigkeit ist in das Gerät eingedrungen. c – Das Gerät war Feuchtigkeit ausgesetzt. d – Wenn das Gerät nicht der Bedienungsanleitung ensprechend funktioniert oder Sie mit Hilfe dieser Anleitung keine Verbesserung erzielen. e – Das Gerät ist gefallen und/oder das Gehäuse ist beschädigt. f – Wenn das Gerät deutliche Anzeichen eines Defektes aufweist.
16. Bei Reparaturen dürfen nur Orginalersatzteile bzw. den Orginalteilen entsprechende Teile verwendet werden. Der Einsatz von ungeeigneten
Ersatzteilen kann eine weitere Beschädigung hervorrufen.
17. Wenden Sie sich mit allen Fragen die Service und Repartur betreffen an Ihren Servicepartner. Somit stellen Sie die Betriebssicherheit des
Gerätes sicher.
18. Zum Netzanschluß dieses Gerätes ist eine geprüfte Leitung zu verwenden, Für einen Nennstrom bis 6A und einem Gerätegewicht grőßer 3kg ist eine Leitung nicht leichter als H05VV-F, 3G, 0.75mm2 einzusetzen. ii
WARRANTIES EXCLUSIVE
IF THE D-LINK PRODUCT DOES NOT OPERATE AS WARRANTED ABOVE, THE CUSTOMER'S SOLE REMEDY SHALL BE, AT D-LINK'S OPTION,
REPAIR OR REPLACEMENT. THE FOREGOING WARRANTIES AND REMEDIES ARE EXCLUSIVE AND ARE IN LIEU OF ALL OTHER WARRANTIES,
EXPRESSED OR IMPLIED, EITHER IN FACT OR BY OPERATION OF LAW, STATUTORY OR OTHERWISE, INCLUDING WARRANTIES OF
MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. D-LINK NEITHER ASSUMES NOR AUTHORIZES ANY OTHER PERSON TO
ASSUME FOR IT ANY OTHER LIABILITY IN CONNECTION WITH THE SALE, INSTALLATION MAINTENANCE OR USE OF D-LINK'S PRODUCTS
D-LINK SHALL NOT BE LIABLE UNDER THIS WARRANTY IF ITS TESTING AND EXAMINATION DISCLOSE THAT THE ALLEGED DEFECT IN THE
PRODUCT DOES NOT EXIST OR WAS CAUSED BY THE CUSTOMER'S OR ANY THIRD PERSON'S MISUSE, NEGLECT, IMPROPER INSTALLATION
OR TESTING, UNAUTHORIZED ATTEMPTS TO REPAIR, OR ANY OTHER CAUSE BEYOND THE RANGE OF THE INTENDED USE, OR BY
ACCIDENT, FIRE, LIGHTNING OR OTHER HAZARD.
LIMITATION OF LIABILITY
IN NO EVENT WILL D-LINK BE LIABLE FOR ANY DAMAGES, INCLUDING LOSS OF DATA, LOSS OF PROFITS, COST OF COVER OR OTHER
INCIDENTAL, CONSEQUENTIAL OR INDIRECT DAMAGES ARISING OUT THE INSTALLATION, MAINTENANCE, USE, PERFORMANCE, FAILURE
OR INTERRUPTION OF A D- LINK PRODUCT, HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY. THIS LIMITATION WILL APPLY EVEN IF
D-LINK HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
IF YOU PURCHASED A D-LINK PRODUCT IN THE UNITED STATES, SOME STATES DO NOT ALLOW THE LIMITATION OR EXCLUSION OF
LIABILITY FOR INCIDENTAL OR CONSEQUENTIAL DAMAGES, SO THE ABOVE LIMITATION MAY NOT APPLY TO YOU.
Limited Warranty
Hardware:
D-Link warrants each of its hardware products to be free from defects in workmanship and materials under normal use and service for a period commencing on the date of purchase from D-Link or its Authorized Reseller and extending for the length of time stipulated by the Authorized
Reseller or D-Link Branch Office nearest to the place of purchase.
This Warranty applies on the condition that the product Registration Card is filled out and returned to a D-Link office within ninety (90) days of purchase. A list of D-Link offices is provided at the back of this manual, together with a copy of the Registration Card.
If the product proves defective within the applicable warranty period, D-Link will provide repair or replacement of the product. D-Link shall have the sole discretion whether to repair or replace, and replacement product may be new or reconditioned. Replacement product shall be of equivalent or better specifications, relative to the defective product, but need not be identical. Any product or part repaired by D-Link pursuant to this warranty shall have a warranty period of not less than 90 days, from date of such repair, irrespective of any earlier expiration of original warranty period. When D-Link provides replacement, then the defective product becomes the property of D-Link.
Warranty service may be obtained by contacting a D-Link office within the applicable warranty period, and requesting a Return Material
Authorization (RMA) number. If a Registration Card for the product in question has not been returned to D-Link, then a proof of purchase (such as a copy of the dated purchase invoice) must be provided. If Purchaser's circumstances require special handling of warranty correction, then at the time of requesting RMA number, Purchaser may also propose special procedure as may be suitable to the case.
After an RMA number is issued, the defective product must be packaged securely in the original or other suitable shipping package to ensure that it will not be damaged in transit, and the RMA number must be prominently marked on the outside of the package. The package must be mailed or otherwise shipped to D-Link with all costs of mailing/shipping/insurance prepaid. D-Link shall never be responsible for any software, firmware, information, or memory data of Purchaser contained in, stored on, or integrated with any product returned to D-Link pursuant to this warranty.
Any package returned to D-Link without an RMA number will be rejected and shipped back to Purchaser at Purchaser's expense, and D-Link reserves the right in such a case to levy a reasonable handling charge in addition mailing or shipping costs.
Software:
Warranty service for software products may be obtained by contacting a D-Link office within the applicable warranty period. A list of D-Link offices is provided at the back of this manual, together with a copy of the Registration Card. If a Registration Card for the product in question has not been returned to a D-Link office, then a proof of purchase (such as a copy of the dated purchase invoice) must be provided when requesting warranty service. The term "purchase" in this software warranty refers to the purchase transaction and resulting license to use such software.
D-Link warrants that its software products will perform in substantial conformance with the applicable product documentation provided by D-Link with such software product, for a period of ninety (90) days from the date of purchase from D-Link or its Authorized Reseller. D-Link warrants the magnetic media, on which D-Link provides its software product, against failure during the same warranty period. This warranty applies to purchased software, and to replacement software provided by D-Link pursuant to this warranty, but shall not apply to any update or replacement which may be provided for download via the Internet, or to any update which may otherwise be provided free of charge.
D-Link's sole obligation under this software warranty shall be to replace any defective software product with product which substantially conforms to D-Link's applicable product documentation. Purchaser assumes responsibility for the selection of appropriate application and system/platform software and associated reference materials. D-Link makes no warranty that its software products will work in combination with any hardware, or any application or system/platform software product provided by any third party, excepting only such products as are expressly represented, in
D-Link's applicable product documentation as being compatible. D-Link's obligation under this warranty shall be a reasonable effort to provide compatibility, but D-Link shall have no obligation to provide compatibility when there is fault in the third-party hardware or software. D-Link makes no warranty that operation of its software products will be uninterrupted or absolutely error-free, and no warranty that all defects in the software product, within or without the scope of D-Link's applicable product documentation, will be corrected.
D-Link Offices for Registration and Warranty Service
The product's Registration Card, provided at the back of this manual, must be sent to a D-Link office. To obtain an RMA number for warranty service as to a hardware product, or to obtain warranty service as to a software product, contact the D-Link office nearest you. An address/telephone/fax/e-mail/Web site list of D-Link offices is provided in the back of this manual.
Trademarks
Copyright 2002 D-Link Corporation.
Contents subject to change without prior notice.
D-Link is a registered trademark of D-Link Corporation/D-Link Systems, Inc. All other trademarks belong to their respective proprietors.
Copyright Statement
No part of this publication may be reproduced in any form or by any means or used to make any derivative such as translation, transformation, or adaptation without permission from D-Link Corporation/D-Link Systems Inc., as stipulated by the United States Copyright Act of 1976. iv
FCC Warning
This equipment has been tested and found to comply with the limits for a Class A digital device, pursuant to Part
15 of the FCC Rules. These limits are designed to provide reasonable protection against harmful interference when the equipment is operated in a commercial environment. This equipment generates, uses, and can radiate radio frequency energy and, if not installed and used in accordance with this user’s guide, may cause harmful interference to radio communications. Operation of this equipment in a residential area is likely to cause harmful interference in which case the user will be required to correct the interference at his own expense.
CE Mark Warning
This is a Class A product. In a domestic environment, this product may cause radio interference in which case the user may be required to take adequate measures.
VCCI Warning
BSMI Warning
Table of Contents
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viii
ix
DES-3326 Layer 3 Fast Ethernet Switch User’s Guide
1
I
NTRODUCTION
This section describes the Layer 3 functionality and Layer 2 and Layer 3 features of the DES-3326.
Some background information about Ethernet/Fast Ethernet, Gigabit Ethernet, and switching technology is presented. This is intended for readers who may not be familiar with the concepts of layered switching and routing but is not intended to be a complete or in-depth discussion.
Layer 3 Switching
Layer 3 switching is the integration of two proven technologies: switching and routing. In fact, Layer 3 switches are running the same routing routines and protocols as traditional routers. The main difference between traditional routing and Layer 3 switching is the addition of a group of Layer 2 switching domains and the execution of routing routines for most packets via an ASIC – in hardware instead of software.
Where a traditional router would have one, or at best a few, Fast Ethernet ports, the DES-3326 Layer 3 switch has 24 Fast Ethernet ports and optionally, 2 Gigabit Ethernet ports. Where a traditional router would have one or two high-speed serial WAN connections, the DES-3326 relies upon a Fast Ethernet port to connect to a separate device, which in turn, connects the network to a WAN or the Internet.
The DES-3326 can be thought of as 24 Fast Ethernet Layer 2 switching domains with a wire-speed router between each domain. It can be deployed in a network between a traditional router and the intranetwork. The traditional router and its associated WAN interface would then handle routing between the intranetwork and the WAN (the Internet, for example) while the Layer 3 switch would handle routing within the LAN (between the Fast Ethernet Layer 2 domains). Any installed Layer 2 switches, and indeed the entire subnetting scheme, would remain in place.
The DES-3326 can also replace key traditional routers for data centers and server farms, routing between these locations and the rest of the network, and providing 24 ports of Layer 2 switching performance combined with wire-speed routing.
Backbone routers can also be replaced with DES-3326 and a series of DES-3326 could be linked via the optional Gigabit Ethernet ports. Routers that service WAN connections would remain in place, but would now be removed from the backbone and connected to the DES-3326 via an Ethernet/Fast
Ethernet port. The backbone itself could be migrated to Gigabit Ethernet, or faster technologies as they become available.
The DES-3326 accomplishes two objectives. First as a tool to provide high-performance access to enterprise data servers and infrastructure, and second, to enhance the performance of network equipment already installed. Many network segments display poor performance, but the Ethernet wire is only carrying a fraction of its total traffic capacity. The problem is not the network, but the ability of the connected devices utilize the full capacity of the network. The DES-3326 can eliminate network bottlenecks to high-traffic areas, and improve the utilization of the network’s installed bandwidth.
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DES-3326 Layer 3 Fast Ethernet Switch User’s Guide
The Functions of a Layer 3 Switch
Traditional routers, once the core components of large networks, became an obstacle to the migration toward next-generation networks. Attempts to make software-based routers forward packets more quickly were inadequate.
A layer 3 switch does everything to a packet that a traditional router does:
• Determines forwarding path based on Layer 3 information
• Validates the integrity of the Layer 3 header via checksum
• Verifies packet expiration and updates accordingly
• Processes and responds to any optional information
• Updates forwarding statistics in the Management Information Base
A Layer 3 switch can be placed anywhere within a network core or backbone, easily and cost-effectively replacing the traditional collapsed backbone router. The DES-3326 Layer 3 switch communicates with a WAN router using a standard Ethernet/Fast Ethernet port. Multiple DES-3326 switches can be linked via the optional, 2-port Gigabit Ethernet module.
Features
The DES-3326 Switch was designed for easy installation and high performance in an environment where traffic on the network and the number of users increase continuously.
Switch features include:
Ports
• 24 high-performance NWay ports all operating at 10/100 Mbps for connecting to end stations, servers and hubs (23 MDI-X 10/100 Ethernet UTP ports and one MDI-II/MDI-X port. The MDI-
II/MDI-X port can be switched between the two modes from the front panel.)
• All ports can auto-negotiate (NWay) between 10Mbps/ 100Mbps, half-duplex or full duplex and flow control for half-duplex ports.
• One front panel slide-in module interface for a 2-port 1000BASE-SX, 1000BASE-LX, 1000BASE-
T, or GBIC Gigabit Ethernet module.
• RS-232 DCE Diagnostic port (console port) for setting up and managing the Switch via a connection to a console terminal or PC using a terminal emulation program.
Performance Features
Layer 2 Features
• 8.8 Gbps switching fabric capacity
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DES-3326 Layer 3 Fast Ethernet Switch User’s Guide
• Store and forward switching scheme.
• Full and half-duplex for both 10Mbps and 100Mbps connections. The front-port Gigabit Ethernet module operates at full duplex only. Full duplex allows the switch port to simultaneously transmit and receive data, and only works with connections to full-duplex capable end stations and switches. Connections to hubs must take place at half-duplex.
• Supports IEEE 802.3x flow control for full-duplex mode ports.
• Supports Back-pressure flow control for half-duplex mode ports.
• Auto-polarity detection and correction of incorrect polarity on the transmit and receive twistedpair at each port.
• IEEE 802.3z compliant for all Gigabit ports (optional module).
• IEEE 802.3x compliant Flow Control support for all Gigabit ports (optional module).
• IEEE 802.3ab compliant for 1000BASE-T (Copper) Gigabit ports (optional module).
• Data forwarding rate 14,880 pps per port at 100% of wire-speed for 10Mbps speed.
• Data forwarding rate 148,800 pps per port at 100% of wire-speed for 100Mbps speed.
• Data filtering rate eliminates all error packets, runts, etc. at 14,880 pps per port at 100% of wirespeed for 10Mbps speed.
• Data filtering rate eliminates all error packets, runts, etc. at 148,800 pps per port at 100% of wire-speed for 100Mbps speed.
• 8K active MAC address entry table per device with automatic learning and aging (10 to 9999 seconds).
• 16 MB packet buffer per device.
• Broadcast and Multicast storm filtering.
• Supports Port Mirroring.
• Supports Port Trunking – up to six trunk groups (each consisting of up to eight ports) may be set up.
• 802.1D Spanning Tree support.
• 802.1Q Tagged VLAN support – up to 63 User-defined VLANs per device (one VLAN is reserved for internal use).
• GVRP – (GARP VLAN Registration Protocol) support for dynamic VLAN registration.
• 802.1p Priority support with 4 priority queues.
• IGMP Snooping support.
• Layer 2 Multicast support – GMRP (GARP Multicast Registration Protocol).
Layer 3 Switch Features
• Wire speed IP forwarding.
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DES-3326 Layer 3 Fast Ethernet Switch User’s Guide
• Hardware-based Layer 3 IP switching.
• IP packet forwarding rate of 6.6 Mpps.
• 2K active IP address entry table per device.
• Supports RIP – (Routing Information Protocol) version I and II.
• Supports OSPF − (Open Shortest Path First)
• Supports MD5 and Password OSPF Packet Authentication
• Supports IP version 4.
• IGMP version 1 and 2 support (RFC 1112 and RFC 2236).
• Supports PIM Dense Mode.
• Supports DVMRP.
• Supports IP multi-netting.
• Supports IP packet de-fragmentation.
• Supports Path MTU discovery.
• Supports 802.1D frame support.
Traffic Classification and Prioritization
• Based on 802.1p priority bits
• 4 priority queues
Management
• RS-232 console port for out-of-band network management via a console terminal or PC.
• Spanning Tree Algorithm Protocol for creation of alternative backup paths and prevention of network loops.
• SNMP v.1 Agent.
• Fully configurable either in-band or out-of-band control via SNMP based software.
• Flash memory for software upgrades. This can be done in-band via TFTP or out-of-band via the console.
• Built-in SNMP management:
Bridge MIB (RFC 1493)
MIB-II (RFC 1213)
Mini-RMON MIB (RFC 1757) – 4 groups
CIDR MIB (RFC 2096), except IP Forwarding Table.
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DES-3326 Layer 3 Fast Ethernet Switch User’s Guide
802.1p MIB (RFC 2674).
RIP MIB v2 (RFC 1724).
• Supports Web-based management.
• TFTP support.
• BOOTP support.
• BOOTP Relay Agent.
• IP filtering on the management interface.
• DHCP Client support.
• DHCP Relay Agent.
• DNS Relay Agent.
• Password enabled.
Optional Redundant Power Supply
The DES-3326 24+2 Fast Ethernet Layer 3 Switch supports the optional DPS-1000 (Redundant Power
Supply) to provide automatic power supply monitoring and switchover to a redundant power supply
(located in the chassis of the DPS-1000) in case of a failure in the DES-3326’s internal power supply.
Fast Ethernet Technology
100Mbps Fast Ethernet (or 100BASE-T) is a standard specified by the IEEE 802.3 LAN committee. It is an extension of the 10Mbps Ethernet standard with the ability to transmit and receive data at
100Mbps, while maintaining the Carrier Sense Multiple Access with Collision Detection (CSMA/CD)
Ethernet protocol.
Gigabit Ethernet Technology
Gigabit Ethernet is an extension of IEEE 802.3 Ethernet utilizing the same packet structure, format, and support for CSMA/CD protocol, full duplex, flow control, and management objects, but with a tenfold increase in theoretical throughput over 100Mbps Fast Ethernet and a one hundred-fold increase over 10Mbps Ethernet. Since it is compatible with all 10Mbps and 100Mbps Ethernet environments, Gigabit Ethernet provides a straightforward upgrade without wasting a company’s existing investment in hardware, software, and trained personnel.
Gigabit Ethernet enables fast optical fiber connections and Unshielded Twisted Pair connections to support video conferencing, complex imaging, and similar data-intensive applications. Likewise, since data transfers occur 10 times faster than Fast Ethernet, servers outfitted with Gigabit Ethernet NIC’s are able to perform 10 times the number of operations in the same amount of time.
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DES-3326 Layer 3 Fast Ethernet Switch User’s Guide
2
U
NPACKING AND
S
ETUP
This chapter provides unpacking and setup information for the Switch.
Unpacking
Open the shipping carton of the Switch and carefully unpack its contents. The carton should contain the following items:
♦ One DES-3326 24-port Fast Ethernet Layer 3 Switch
♦ Mounting kit: 2 mounting brackets and screws
♦ Four rubber feet with adhesive backing
♦ One AC power cord
♦ This User’s Guide with Registration Card
If any item is found missing or damaged, please contact your local D-Link reseller for replacement.
Installation
Use the following guidelines when choosing a place to install the Switch:
♦ The surface must support at least 3 kg.
♦ The power outlet should be within 1.82 meters (6 feet) of the device.
♦ Visually inspect the power cord and see that it is secured to the AC power connector.
♦ Make sure that there is proper heat dissipation from and adequate ventilation around the switch.
Do not place heavy objects on the switch.
Desktop or Shelf Installation
When installing the Switch on a desktop or shelf, the rubber feet included with the device should first be attached. Attach these cushioning feet on the bottom at each corner of the device. Allow adequate space for ventilation between the device and the objects around it.
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DES-3326 Layer 3 Fast Ethernet Switch User’s Guide
Figure 2-1. Installing rubber feet for desktop installation
Rack Installation
The DES-3326 can be mounted in an EIA standard-sized, 19-inch rack, which can be placed in a wiring closet with other equipment. To install, attach the mounting brackets on the switch’s side panels (one on each side) and secure them with the screws provided.
Figure 2- 2A. Attaching the mounting brackets to the switch
Then, use the screws provided with the equipment rack to mount the switch on the rack.
Figure 2-2B. Installing the switch on an equipment rack
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DES-3326 Layer 3 Fast Ethernet Switch User’s Guide
Power on
The DES-3326 switch can be used with AC power supply 100-240 VAC, 50 - 60 Hz. The power switch is located at the rear of the unit adjacent to the AC power connector and the system fan. The switch’s power supply will adjust to the local power source automatically and may be turned on without having any or all LAN segment cables connected.
After the power switch is turned on, the LED indicators should respond as follows:
♦ All LED indicators will momentarily blink. This blinking of the LED indicators represents a reset of the system.
♦ The power LED indicator will blink while the Switch loads onboard software and performs a selftest. After approximately 20 seconds, the LED will light again to indicate the switch is in a ready state.
♦ The console LED indicator will remain ON if there is a connection at the RS-232 port, otherwise this LED indicator is OFF.
♦ The 100M LED indicator may remain ON or OFF depending on the transmission speed.
Power Failure
As a precaution in the event of a power failure, unplug the switch. When power is resumed, plug the switch back in.
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DES-3326 Layer 3 Fast Ethernet Switch User’s Guide
3
I
DENTIFYING
E
XTERNAL
C
OMPONENTS
This chapter describes the front panel, rear panel, optional plug-in modules, and LED indicators of the
DES-3326.
Front Panel
The front panel of the Switch consists of LED indicators, an RS-232 communication port, a slide-in module slot, one switched MDI-X/MDI-II uplink port, and 23 (10/100 Mbps) Ethernet/Fast Ethernet ports.
Figure 3-1. Front panel view of the Switch
♦ Comprehensive LED indicators display the status of the switch and the network (see the LED
Indicators section below).
♦ An RS-232 DCE console port for setting up and managing the switch via a connection to a console terminal or PC using a terminal emulation program.
♦ A front-panel slide-in module slot for Gigabit Ethernet ports can accommodate a 2-port
1000BASE-T Gigabit Ethernet module, a 2-port 1000BASE-SX Gigabit Ethernet module, a 2-port
1000BASE-LX Gigabit Ethernet module, or a 2-port GBIC-based Gigabit Ethernet module.
♦ One switched MDI-X/MDI-II Uplink port that can be used to connect a straight-through cable or a crossed cable to a normal (non-Uplink) port on a switch or hub. This port is identical to the other
23 ports except for the ability to use a crossed or a straight-through cable.
♦ Twenty-three high-performance, NWay Ethernet ports all of which operate at 10/100 Mbps for connections to end stations, servers and hubs. All ports can auto-negotiate between 10Mbps or
100Mbps, full or half duplex, and flow control.
Rear Panel
The rear panel of the switch consists of a slot for the optional DPS-1000 (Redundant Power Supply) and an AC power connector.
Figure 3-2. Rear panel view of the Switch
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DES-3326 Layer 3 Fast Ethernet Switch User’s Guide
♦ The AC power connector is a standard three-pronged connector that supports the power cord.
Plug-in the female connector of the provided power cord into this socket, and the male side of the cord into a power outlet. Supported input voltages range from 100 ~ 240 VAC at 50 ~ 60 Hz.
Side Panels
The right side panel of the Switch contains two system fans (see the top part of the diagram below). The left side panel contains heat vents.
Figure 3-4. Side panel views of the Switch
♦ The system fans are used to dissipate heat. The sides of the system also provide heat vents to serve the same purpose. Do not block these openings, and leave at least 6 inches of space at the rear and sides of the switch for proper ventilation. Be reminded that without proper heat dissipation and air circulation, system components might overheat, which could lead to system failure.
Optional Plug-in Modules
The DES 3326 24-port Fast Ethernet Layer 3 Switch is able to accommodate a range of optional plug-in modules in order to increase functionality and performance. These modules must be purchased separately.
1000BASE-T Module
Figure 3-5. 1000BASE-TX two-port module
♦ Front-panel module.
♦ Connects to 1000BASE-T devices.
♦ Supports Category 5e UTP or STP cable connections of up to 100 meters.
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DES-3326 Layer 3 Fast Ethernet Switch User’s Guide
1000BASE-SX Fiber Module
Figure 3-6. 1000BASE-SX two-port module
♦ Front-panel module.
♦ Connects to 1000BASE-SX devices at full duplex.
♦ Allows connections using multi-mode fiber optic cable in the following configurations:
62.5µm 62.5µm 50µm 50µm
160 200 400 500 Modal bandwidth
(min. overfilled launch)
Unit: MHz*km
Operating distance
Unit: meters
Channel insertion loss
Unit: dB
1000BASE-LX Fiber Module
Figure 3-7. 1000BASE-LX two-port module
♦ Front-panel module.
♦ Connects to 1000BASE-LX devices at full duplex.
♦ Supports multi-mode fiber-optic cable connections of up to 550 meters or 5 km single-mode fiberoptic cable connections.
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DES-3326 Layer 3 Fast Ethernet Switch User’s Guide
GBIC Two-Port Module
Figure 3-8. GBIC two-port module
♦ Front-panel module.
♦ Connects to GBIC devices at full duplex only.
♦ Allows multi-mode fiber optic connections of up to 550 m (SX and LX) and single-mode fiber optic connections of up to 5 km (LX only). GBIC modules are available in –SX and –LX fiber optic media.
LED Indicators
The LED indicators of the Switch include Power, Console, and Link/Act. The following shows the LED indicators for the Switch along with an explanation of each indicator.
Figure 3-9. The LED indicators
♦ Power This indicator on the front panel should be lit during the Power-On Self Test (POST). It will light green approximately 2 seconds after the switch is powered on to indicate the ready state of the device.
♦ Console This indicator is lit green when the switch is being managed via out-of-band/local console management through the RS-232 console port using a straight-through serial cable.
♦ Link/Act These indicators are located to the left and right of each port. They are lit when there is a secure connection (or link) to a device at any of the ports. The LEDs blink whenever there is reception or transmission (i.e. Activity--Act) of data occurring at a port.
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DES-3326 Layer 3 Fast Ethernet Switch User’s Guide
4
C
ONNECTING
T
HE
S
WITCH
This chapter describes how to connect the DES 3326 to your Fast Ethernet network.
Switch to End Node
End nodes include PCs outfitted with a 10, 100 or 10/100 Mbps RJ-45 Ethernet/Fast Ethernet
Network Interface Card (NIC) and most routers. The RJ-45 UTP ports on NICs and most routers are
MDI-II. When using a normal straight-through cable, an MDI-II port must connect to an MDI-X port.
An end node can be connected to the Switch via a two-pair Category 3, 4, 5 UTP/STP straight cable (be sure to use Category 5e UTP or STP cabling for 100 Mbps Fast Ethernet connections). The end node should be connected to any of the twenty-three ports (2x - 24x) of the DES-3326 or to either of the two
100BASE-TX ports on the front-panel module that came preinstalled on the switch. Port 1x can be used as an uplink port to connect to another switch using either a crossed or a straight-through cable.
This port is switched between MDI-X and MDI-II to accommodate either type of cable.
Figure 4-1. Switch connected to an End Node
The LED indicators for the port the end node is connected to are lit according to the capabilities of the
NIC. If LED indicators are not illuminated after making a proper connection, check the PC’s LAN card, the cable, switch conditions, and connections.
The following LED indicator states are possible for an end node to switch connection:
1. The 100 LED indicator comes ON for a 100 Mbps and stays OFF for 10 Mbps.
2. The Link/Act LED indicator lights up upon hooking up a PC that is powered on.
Switch to Hub or Switch
These connections can be accomplished in a number of ways. The most important consideration is that when using a normal, straight-through cable, the connection should be made between a normal crossed port (Port 2x, 3x, etc.) and an Uplink (MDI-II) port. If you are using a crossover cable, the connection must be made from Uplink to Uplink (port 1x on the DES-3326), or from a crossed port to another crossed port.
22
DES-3326 Layer 3 Fast Ethernet Switch User’s Guide
♦ A 10BASE-T hub or switch can be connected to the Switch via a two-pair Category 3, 4 or 5
UTP/STP straight cable.
♦ A 100BASE-TX hub or switch can be connected to the Switch via a two-pair Category 5e UTP/STP straight cable.
If the other switch or hub contains an unused Uplink port, we suggest connecting the other device’s
Uplink (MDI-II) port to any of the switch’s (MDI-X) ports (1x - 22x, or one of the optional Gigabit module ports) using a normal straight-through cable, as shown below.
If the other device does not have an unused Uplink port, make the connection with a normal straightthrough cable from the Uplink port on the switch to any normal crossed port on the hub. Alternatively, if you have a crossover cable you can save the Uplink ports for other connections and make this one from a crossed port to another crossed port.
Figure 4-2. Switch connected to a normal (non-Uplink) port on a hub or switch using a straight or crossover cable
10BASE-T Device
For a 10BASE-T device, the Switch’s LED indicators should display the following:
♦ 100 LED speed indicator is OFF.
♦ Link/Act indicator is ON.
100BASE-TX Device
For a 100BASE-TX device, the Switch’s LED indicators should display the following:
♦ 100 LED speed indicator is ON.
♦ Link/Act is ON.
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DES-3326 Layer 3 Fast Ethernet Switch User’s Guide
5
S
WITCH
M
ANAGEMENT AND
O
PERATING
C
ONCEPTS
This chapter discusses many of the concepts and features used to manage the switch, as well as the concepts necessary for the user to understand the functioning of the switch. Further, this chapter explains many important points regarding these features.
Configuring the switch to implement these concepts and make use of its many features is discussed in detail in the next chapters.
Local Console Management
A local console is a terminal or a workstation running a terminal emulation program that is connected directly to the switch via the RS-232 console port on the front of the switch. A console connection is referred to as an ‘Out-of-Band’ connection, meaning that console is connected to the switch using a different circuit than that used for normal network communications. So, the console can be used to set up and manage the switch even if the network is down.
Local console management uses the terminal connection to operate the console program built-in to the switch (see Chapter 6, “Using the Console Interface”). A network administrator can manage, control and monitor the switch from the console program.
The DES-3326 contains a CPU, memory for data storage, flash memory for configuration data, operational programs, and SNMP agent firmware. These components allow the switch to be actively managed and monitored from either the console port or the network itself (out-of-band, or in-band).
Diagnostic (console) port (RS-232 DCE)
Out-of-band management requires connecting a terminal, such as a VT-100 or a PC running a terminal emulation program (such as HyperTerminal, which is automatically installed with Microsoft Windows) a to the RS-232 DCE console port of the Switch. Switch management using the RS-232 DCE console port is called Local Console Management to differentiate it from management performed via management platforms, such as D-View, HP OpenView, etc. Web-based Management describes management of the switch performed over the network (in-band) using the switch’s built-in Web-based management program (see Chapter 7, “Web-based Network Management”). The operations to be performed and the facilities provided by these two built-in programs are identical.
The console port is set at the factory for the following configuration:
• Parity:
• Stop bits:
24 none
1
DES-3326 Layer 3 Fast Ethernet Switch User’s Guide
Make sure the terminal or PC you are using to make this connection is configured to match these settings.
If you are having problems making this connection on a PC, make sure the emulation is set to VT-
100. If you still don’t see anything, try hitting <Ctrl> + r to refresh the screen.
IP Addresses and SNMP Community Names
Each Switch must be assigned its own IP Address, which is used for communication with an SNMP network manager or other TCP/IP application (for example BOOTP, TFTP). The switch’s default IP address is 10.90.90.90. You can change the default Switch IP Address to meet the specification of your networking address scheme.
The switch is also assigned a unique MAC address by the factory. This MAC address cannot be changed, and can be found from the initial boot console screen – shown below.
Figure 5-1. Boot screen
The switch’s MAC address can also be found from the console program under the Switch Information menu item, as shown below.
Figure 5-2. Switch Information screen
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DES-3326 Layer 3 Fast Ethernet Switch User’s Guide
In addition, you can also set an IP Address for a gateway router. This becomes necessary when the network management station is located on a different IP network from the Switch, making it necessary for management packets to go through a router to reach the network manager, and vice-versa.
For security, you can set in the Switch a list of IP Addresses of the network managers that you allow to manage the Switch. You can also change the default SNMP Community Strings in the Switch and set the access rights of these Community Strings. In addition, a VLAN may be designated as a
Management VLAN.
Traps
Traps are messages that alert you of events that occur on the Switch. The events can be as serious as a reboot (someone accidentally turned OFF the Switch), or less serious like a port status change. The
Switch generates traps and sends them to the network manager (trap recipient).
Trap recipients are special users of the network who are given certain rights and access in overseeing the maintenance of the network. Trap recipients will receive traps sent from the Switch; they must immediately take certain actions to avoid future failure or breakdown of the network.
You can also specify which network managers may receive traps from the Switch by entering a list of the IP addresses of authorized network managers. Up to four trap recipient IP addresses, and four corresponding SNMP community strings can be entered.
SNMP community strings function like passwords in that the community string entered for a given IP address must be used in the management station software, or a trap will be sent.
The following are trap types the switch can send to a trap recipient:
• Cold Start This trap signifies that the Switch has been powered up and initialized such that software settings are reconfigured and hardware systems are rebooted. A cold start is different from a factory reset in that configuration settings saved to non-volatile RAM used to reconfigure the switch.
• Warm Start This trap signifies that the Switch has been rebooted, however the POST (Power
On Self-Test) is skipped.
• Authentication Failure This trap signifies that someone has tried to logon to the switch using an invalid SNMP community string. The switch automatically stores the source IP address of the unauthorized user.
• New Root This trap indicates that the Switch has become the new root of the Spanning Tree, the trap is sent by the switch soon after its election as the new root. This implies that upon expiration of the Topology Change Timer the new root trap is sent out immediately after the
Switch’s election as the new root.
• Topology Change (STP) A Topology Change trap is sent by the Switch when any of its configured ports transitions from the Learning state to the Forwarding state, or from the
Forwarding state to the Blocking state. The trap is not sent if a new root trap is sent for the same transition.
• Link Up This trap is sent whenever the link of a port changes from link down to link up.
• Link Down This trap is sent whenever the link of a port changes from link up to link down.
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DES-3326 Layer 3 Fast Ethernet Switch User’s Guide
SNMP
The Simple Network Management Protocol (SNMP) is an OSI layer 7 (the application layer) protocol for remotely monitoring and configuring network devices. SNMP enables network management stations to read and modify the settings of gateways, routers, switches, and other network devices. SNMP can be used to perform many of the same functions as a directly connected console, or can be used within an integrated network management software package such as DView or NetView.
SNMP performs the following functions:
• Sending and receiving SNMP packets through the IP protocol.
• Collecting information about the status and current configuration of network devices.
• Modifying the configuration of network devices.
The DES-3326 has a software program called an ‘agent’ that processes SNMP requests, but the user program that makes the requests and collects the responses runs on a management station (a designated computer on the network). The SNMP agent and the user program both use the UDP/IP protocol to exchange packets.
Authentication
The authentication protocol ensures that both the router SNMP agent and the remote user SNMP application program discard packets from unauthorized users. Authentication is accomplished using
‘community strings’, which function like passwords. The remote user SNMP application and the router
SNMP must use the same community string. SNMP community strings of up to 20 characters may be entered under the Remote Management Setup menu of the console program.
Traps
Traps are messages that alert network personnel of events that occur on the Switch. The events can be as serious as a reboot (someone accidentally turned OFF the Switch), or less serious like a port status change. The Switch generates traps and sends them to the trap recipient (or network manager).
Trap recipients are special users of the network who are given certain rights and access in overseeing the maintenance of the network. Trap recipients will receive traps sent from the Switch; they must immediately take certain actions to avoid future failure or breakdown of the network.
You can also specify which network managers may receive traps from the Switch by entering a list of the IP addresses of authorized network managers. Up to four trap recipient IP addresses, and four corresponding SNMP community strings can be entered.
SNMP community strings function like passwords in that the community string entered for a given IP address must be used in the management station software, or a trap will be sent.
The following are trap types the switch can send to a trap recipient:
• Cold Start This trap signifies that the Switch has been powered up and initialized such that software settings are reconfigured and hardware systems are rebooted. A cold start is different from a factory reset in that configuration settings saved to nonvolatile RAM used to reconfigure the switch.
• Warm Start This trap signifies that the Switch has been rebooted, however the POST
(Power On Self-Test) is skipped.
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DES-3326 Layer 3 Fast Ethernet Switch User’s Guide
•
•
•
•
•
Authentication Failure This trap signifies that someone has tried to logon to the switch using an invalid SNMP community string. The switch automatically stores the source IP address of the unauthorized user.
Topology Change A Topology Change trap is sent by the Switch when any of its configured ports transitions from the Learning state to the Forwarding state, or from the Forwarding state to the Blocking state. The trap is not sent if a new root trap is sent for the same transition.
Link Change Event This trap is sent whenever the link of a port changes from link up to link down or from link down to link up.
Port Partition This trap is sent whenever the port state enters the partition mode (or automatic partitioning, port disable) when more than thirty-two collisions occur while transmitting at 10Mbps or more than sixty-four collisions occur while transmitting at
100Mbps.
Broadcast\Multicast Storm This trap is sent whenever the port reaches the threshold (in packets per second) set globally for the switch. Counters are maintained for each port, and separate counters are maintained for broadcast and multicast packets. The switch’s default setting is 128 kpps for both broadcast and multicast packets.
MIBs
Management and counter information are stored in the Switch in the Management Information Base
(MIB). The Switch uses the standard MIB-II Management Information Base module. Consequently, values for MIB objects can be retrieved from any SNMP-based network management software. In addition to the standard MIB-II, the Switch also supports its own proprietary enterprise MIB as an extended Management Information Base. These MIBs may also be retrieved by specifying the MIB’s
Object-Identity (OID) at the network manager. MIB values can be either read-only or read-write.
Read-only MIBs variables can be either constants that are programmed into the Switch, or variables that change while the Switch is in operation. Examples of read-only constants are the number of port and type of ports. Examples of read-only variables are the statistics counters such as the number of errors that have occurred, or how many kilobytes of data have been received and forwarded through a port.
Read-write MIBs are variables usually related to user-customized configurations. Examples of these are the Switch’s IP Address, Spanning Tree Algorithm parameters, and port status.
If you use a third-party vendors’ SNMP software to manage the Switch, a diskette listing the Switch’s propriety enterprise MIBs can be obtained by request. If your software provides functions to browse or modify MIBs, you can also get the MIB values and change them (if the MIBs’ attributes permit the write operation). This process however can be quite involved, since you must know the MIB OIDs and retrieve them one by one.
Packet Forwarding
The Switch enters the relationship between destination MAC or IP addresses and the Ethernet port or gateway router the destination resides on into its forwarding table. This information is then used to forward packets. This reduces the traffic congestion on the network, because packets, instead of being
28
DES-3326 Layer 3 Fast Ethernet Switch User’s Guide transmitted to all ports, are transmitted to the destination port only. Example: if Port 1 receives a packet destined for a station on Port 2, the Switch transmits that packet through Port 2 only, and transmits nothing through the other ports. This process is referred to as ‘learning’ the network topology.
MAC Address Aging Time
The Aging Time affects the learning process of the Switch. Dynamic forwarding table entries, which are made up of the source MAC addresses and their associated port numbers, are deleted from the table if they are not accessed within the aging time.
The aging time can be from 10 to 1,000,000 seconds with a default value of 300 seconds. A very long aging time can result in dynamic forwarding table entries that are out-of-date or no longer exist. This may cause incorrect packet forwarding decisions by the switch.
If the Aging Time is too short however, many entries may be aged out too soon. This will result in a high percentage of received packets whose source addresses cannot be found in the forwarding table, in which case the switch will broadcast the packet to all ports, negating many of the benefits of having a switch.
Static forwarding entries are not affected by the aging time.
Filtering
The switch uses a filtering database to segment the network and control communication between segments. It can also filter packets off the network for intrusion control. Static filtering entries can be made by either MAC address or IP address filtering.
Each port on the switch is a unique collision domain and the switch filters (discards) packets whose destination lies on the same port as where it originated. This keeps local packets from disrupting communications on other parts of the network.
For intrusion control, whenever a switch encounters a packet originating from or destined to a MAC address or an IP Address entered into the filter table, the switch will discard the packet.
Some filtering is done automatically by the switch:
• Dynamic filtering – automatic learning and aging of MAC addresses and their location on the network. Filtering occurs to keep local traffic confined to its segment.
• Filtering done by the Spanning Tree Protocol, which can filter packets based on topology, making sure that signal loops don’t occur.
• Filtering done for VLAN integrity. Packets from a member of a VLAN (VLAN 2, for example) destined for a device on another VLAN (VLAN 3) will be filtered.
Some filtering requires the manual entry of information into a filtering table:
• MAC address filtering – the manual entry of specific MAC addresses to be filtered from the network. Packets sent from one manually entered MAC address can be filtered from the network. The entry may be specified as a source, a destination, or both.
• IP address filtering – the manual entry of specific IP addresses to be filtered from the network
(switch must be in IP Routing mode). Packets sent from one manually entered IP address to
29
DES-3326 Layer 3 Fast Ethernet Switch User’s Guide another can be filtered from the network. The entry may specified as a source, a destination, or both (switch must be in IP Routing mode).
Spanning Tree
The IEEE 802.1D Spanning Tree Protocol allows for the blocking of links between switches that form loops within the network. When multiple links between switches are detected, a primary link is established. Duplicated links are blocked from use and become standby links. The protocol allows for the duplicate links to be used in the event of a failure of the primary link. Once the Spanning Tree
Protocol is configured and enabled, primary links are established and duplicated links are blocked automatically. The reactivation of the blocked links (at the time of a primary link failure) is also accomplished automatically – without operator intervention.
The DES-3326 STP allows two levels of spanning trees to be configured. The first level constructs a spanning tree on the links between switches. This is referred to as the Switch or Global level. The second level is on a port group basis. Groups of ports are configured as being members of a spanning tree and the algorithm and protocol are applied to the group of ports. This is referred to as the Port or
VLAN level.
On the switch level, STP calculates the Bridge Identifier for each switch and then sets the Root Bridge and the Designated Bridges.
On the port level, STP sets the Root Port and the Designated Ports.
The following are the user-configurable STP parameters for the switch level: ameter Description Default
Value
32768 + MAC Bridge Identifier
(Not userconfigurable except by setting priority below)
Priority
Hello Time
A combination of the Userset priority and the switch’s
MAC address. The Bridge
Identifier consists of two parts: a 16-bit priority and a 48-bit Ethernet MAC address
A relative priority for each switch – lower numbers give a higher priority and a greater chance of a given switch being elected as the root bridge
The length of time between broadcasts of the hello message by the switch
Maximum Age
Timer
Measures the age of a received BPDU for a port and ensures that the BPDU is discarded when its age exceeds the value of the maximum age timer.
Forward Delay
Timer
The amount time spent by a port in the learning and listening states waiting for a
32768
2 seconds
20 seconds
15 seconds
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DES-3326 Layer 3 Fast Ethernet Switch User’s Guide
BPDU that may return the port to the blocking state.
Table 5-1. STP Parameters – Switch Level
The following are the user-configurable STP parameters for the port or port group level:
Variable Description Default
Value
Port Priority A relative priority for each port – lower numbers give a higher priority and a greater chance of a given port being elected as the root port
128
A value used by STP to evaluate paths – STP calculates path costs and selects the path with the minimum cost as the active path.
19 – 100Mbps
Fast Ethernet ports
10 –
1000Mbps
Gigabit
Ethernet ports
Table 5-2. STP Parameters – Port Group Level
Bridge Protocol Data Units
For STP to arrive at a stable network topology, the following information is used:
• The unique switch identifier
• The path cost to the root associated with each switch port
• The port identifier
STP communicates between switches on the network using Bridge Protocol Data Units (BPDUs). Each
BPDU contains the following information:
• The unique identifier of the switch that the transmitting switch currently believes is the root switch
• The path cost to the root from the transmitting port
• The port identifier of the transmitting port
The switch sends BPDUs to communicate and construct the spanning-tree topology. All switches connected to the LAN on which the packet is transmitted will receive the BPDU. BPDUs are not directly forwarded by the switch, rather the receiving switch uses the information in the frame to calculate a
BPDU, and, if the topology changes, initiates a BPDU transmission.
The communication between switches via BPDUs results in the following:
• One switch is elected as the root switch
• The shortest distance to the root switch is calculated for each switch
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DES-3326 Layer 3 Fast Ethernet Switch User’s Guide
• A designated switch is selected. This is the switch closest to the root switch through which packets will be forwarded to the root.
• A port for each switch is selected. This is the port providing the best path from the switch to the root switch.
• Ports included in the STP are selected.
Creating a Stable STP Topology
If all switches have STP enabled with default settings, the switch with the lowest MAC address in the network will become the root switch. By increasing the priority (lowering the priority number) of the best switch, STP can be forced to select the best switch as the root switch.
When STP is enabled using the default parameters, the path between source and destination stations in a switched network might not be ideal. For instance, connecting higher-speed links to a port that has a higher number than the current root port can cause a root-port change. The goal is to make the fastest link the root port.
STP Port States
The BPDUs take some time to pass through a network. This propagation delay can result in topology changes where a port that transitioned directly from a Blocking state to a Forwarding state could create temporary data loops. Ports must wait for new network topology information to propagate throughout the network before starting to forward packets. They must also wait for the packet lifetime to expire for
BPDU packets that were forwarded based on the old topology. The forward delay timer is used to allow the network topology to stabilize after a topology change.
In addition, STP specifies a series of states a port must transition through to further ensure that a stable network topology is created after a topology change.
Each port on a switch using STP exists is in one of the following five states:
• Blocking – the port is blocked from forwarding or receiving packets
• Listening – the port is waiting to receive BPDU packets that may tell the port to go back to the blocking state
• Learning – the port is adding addresses to its forwarding database, but not yet forwarding packets
• Forwarding – the port is forwarding packets
• Disabled – the port only responds to network management messages and must return to the blocking state first
A port transitions from one state to another as follows:
• From initialization (switch boot) to blocking
• From blocking to listening or to disabled
• From listening to learning or to disabled
• From learning to forwarding or to disabled
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DES-3326 Layer 3 Fast Ethernet Switch User’s Guide
• From forwarding to disabled
• From disabled to blocking
Figure 5-3. STP Port State Transitions
When STP is enabled, every port on every switch in the network goes through the blocking state and then transitions through the states of listening and learning at power up. If properly configured, each port stabilizes to the forwarding or blocking state.
No packets (except BPDUs) are forwarded from, or received by, STP enabled ports until the forwarding state is enabled for that port.
Default Spanning-Tree Configuration
Enable state
Port priority
Port cost
Bridge Priority
STP enabled for all ports
128
19
32,768
Table 5-3. Default STP Parameters
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DES-3326 Layer 3 Fast Ethernet Switch User’s Guide
User-Changeable STA Parameters
The factory default setting should cover the majority of installations. However, it is advisable to keep the default settings as set at the factory; unless, it is absolutely necessary. The user changeable parameters in the Switch are as follows:
• Priority A Priority for the switch can be set from 0 to 65535. 0 is equal to the highest
Priority.
• Hello Time The Hello Time can be from 1 to 10 seconds. This is the interval between two transmissions of BPDU packets sent by the Root Bridge to tell all other Switches that it is indeed the Root Bridge. If you set a Hello Time for your Switch, and it is not the Root Bridge, the set Hello Time will be used if and when your Switch becomes the Root Bridge.
Note: The Hello Time cannot be longer than the Max. Age. Otherwise, a configuration error will occur.
• Max. Age The Max. Age can be from 6 to 40 seconds. At the end of the Max. Age, if a BPDU has still not been received from the Root Bridge, your Switch will start sending its own BPDU to all other Switches for permission to become the Root Bridge. If it turns out that your
Switch has the lowest Bridge Identifier, it will become the Root Bridge.
• Forward Delay Timer The Forward Delay can be from 4 to 30 seconds. This is the time any port on the Switch spends in the listening state while moving from the blocking state to the forwarding state.
Note: Observe the following formulas when setting the above parameters:
Max. Age ≤ 2 x (Forward Delay - 1 second)
Max. Age ≥ 2 x (Hello Time + 1 second)
• Port Priority A Port Priority can be from 0 to 255. The lower the number, the greater the probability the port will be chosen as the Root Port.
• Port Cost A Port Cost can be set from 1 to 65535. The lower the number, the greater the probability the port will be chosen to forward packets.
Illustration of STP
A simple illustration of three Bridges (or three switches) connected in a loop is depicted below. In this example, you can anticipate some major network problems if the STP assistance is not applied. If
Bridge A broadcasts a packet to Bridge B, Bridge B will broadcast it to Bridge C, and Bridge C will broadcast it to back to Bridge A ... and so on. The broadcast packet will be passed indefinitely in a loop, potentially causing a network failure.
STP can be applied as shown in Figure 2-4. In this example, STP breaks the loop by blocking the connection between Bridge B and C. The decision to block a particular connection is based on the STP calculation of the most current Bridge and Port settings. Now, if Bridge A broadcasts a packet to Bridge
C, then Bridge C will drop the packet at port 2 and the broadcast will end there.
Setting-up STP using values other than the defaults, can be complex. Therefore, you are advised to keep the default factory settings and STP will automatically assign root bridges/ports and block loop connections. Influencing STP to choose a particular switch as the root bridge using the Priority setting, or influencing STP to choose a particular port to block using the Port Priority and Port Cost settings is, however, relatively straight forward.
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DES-3326 Layer 3 Fast Ethernet Switch User’s Guide
Figure 5-4. Before Applying the STA Rules
In this example, only the default STP values are used.
Figure 5-6. After Applying the STA Rules
The switch with the lowest Bridge ID (switch C) was elected the root bridge, and the ports were selected to give a high port cost between switches B and C. The two (optional) Gigabit ports (default port cost =
10) on switch A are connected to one (optional) Gigabit port on both switch B and C. The redundant link between switch B and C is deliberately chosen as a 100 Mbps Fast Ethernet link (default port cost
= 19). Gigabit ports could be used, but the port cost should be increased from the default to ensure that the link between switch B and switch C is the blocked link.
Link Aggregation
Link aggregation is used to combine a number of ports together to make a single high-bandwidth data pipeline. The participating parts are called members of a link aggregation group, with one port
35
DES-3326 Layer 3 Fast Ethernet Switch User’s Guide designated as the master port of the group. Since all members of the link aggregation group must be configured to operate in the same manner, the configuration of the master port is applied to all members of the link aggregation group. Thus, when configuring the ports in a link aggregation group, you only need to configure the master port.
The DES-3326 supports link aggregation groups, which may include from 2 to 8 switch ports each, except for a Gigabit link aggregation group which consists of the 2 (optional) Gigabit Ethernet ports of the front panel. These ports are the two 1000BASE-SX, -LX –TX or GBIC ports contained in a frontpanel mounted module.
24
23
24
23
Figure 5-7. Link Aggregation Group
Data transmitted to a specific host (destination address) will always be transmitted over the same port in a link aggregation group. This allows packets in a data stream to arrive in the same order they were sent. A aggregated link connection can be made with any other switch that maintains host-to-host data streams over a single link aggregate port. Switches that use a load-balancing scheme that sends the packets of a host-to-host data stream over multiple link aggregation ports cannot have a aggregated connection with the DES-3326 switch.
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DES-3326 Layer 3 Fast Ethernet Switch User’s Guide
VLANs
A VLAN is a collection of end nodes grouped by logic rather than physical location. End nodes that frequently communicate with each other are assigned to the same VLAN, regardless of where they are located physically on the network. Logically, a VLAN can be equated to a broadcast domain, because broadcast packets are forwarded only to members of the VLAN on which the broadcast was initiated.
Notes About VLANs on the DES-3326
1. The DES-3326 supports IEEE 802.1Q VLANs. The port untagging function can be used to remove the 802.1Q tag from packet headers to maintain compatibility with devices that are tag-unaware (that is, network devices that do not support IEEE 802.1Q VLANs or tagging).
2. The switch’s default - in both Layer 2 Only mode and IP Routing mode - is to assign all ports to a single 802.1Q VLAN named DEFAULT_VLAN
.
3. The switch allows the assignment of an IP interface to each VLAN, in IP Routing mode.
The VLANs must be configured before setting up the IP interfaces
4. A VLAN that is not assigned an IP interface will behave as a layer 2 VLAN – and IP routing, by the switch, will not be possible to this VLAN regardless of the switch’s operating mode.
IEEE 802.1Q VLANs
Some relevant terms:
Tagging - The act of putting 802.1Q VLAN information into the header of a packet.
Untagging - The act of stripping 802.1Q VLAN information out of the packet header.
Ingress port - A port on a switch where packets are flowing into the switch and VLAN decisions must be made.
Egress port - A port on a switch where packets are flowing out of the switch, either to another switch or to an end station, and tagging decisions must be made.
IEEE 802.1Q (tagged) VLANs are implemented on the DES-3326 Layer 3 switch. 802.1Q VLANs require tagging, which enables the VLANs to span an entire network (assuming all switches on the network are
IEEE 802.1Q-compliant).
Any port can be configured as either tagging or untagging. The untagging feature of IEEE 802.1Q VLANs allow VLANs to work with legacy switches that don’t recognize VLAN tags in packet headers. The
tagging feature allows VLANs to span multiple 802.1Q-compliant switches through a single physical connection and allows Spanning Tree to be enabled on all ports and work normally.
802.1Q VLAN Packet Forwarding
Packet forwarding decisions are made based upon the following three types of rules:
• Ingress rules – rules relevant to the classification of received frames belonging to a VLAN.
• Forwarding rules between ports – decides filter or forward the packet
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DES-3326 Layer 3 Fast Ethernet Switch User’s Guide
• Egress rules – determines if the packet must be sent tagged or untagged.
Figure 5-8. IEEE 802.1Q Packet Forwarding
802.1Q VLAN Tags
The figure below shows the 802.1Q VLAN tag. There are four additional octets inserted after the source
MAC address. Their presence is indicated by a value of 0x8100 in the EtherType field. When a packet’s
EtherType field is equal to 0x8100, the packet carries the IEEE 802.1Q/802.1p tag. The tag is contained in the following two octets and consists of 3 bits or user priority, 1 bit of Canonical Format
Identifier (CFI – used for encapsulating Token Ring packets so they can be carried across Ethernet backbones) and 12 bits of VLAN ID (VID). The 3 bits of user priority are used by 802.1p. The VID is the
VLAN identifier and is used by the 802.1Q standard. Because the VID is 12 bits long, 4094 unique
VLANs can be identified.
The tag is inserted into the packet header making the entire packet longer by 4 octets. All of the information contained in the packet originally is retained.
Figure 5-9. IEEE 802.1Q Tag
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DES-3326 Layer 3 Fast Ethernet Switch User’s Guide
The EtherType and VLAN ID are inserted after the MAC source address, but before the original
EtherType/Length or Logical Link Control. Because the packet is now a bit longer than it was originally, the Cyclic Redundancy Check (CRC) must be recalculated.
Figure 5-10. Adding an IEEE 802.1Q Tag
Port VLAN ID
Packets that are tagged (are carrying the 802.1Q VID information) can be transmitted from one 802.1Q compliant network device to another with the VLAN information intact. This allows 802.1Q VLANs to span network devices (and indeed, the entire network – if all network devices are 802.1Q compliant).
Unfortunately, not all network devices are 802.1Q compliant. These devices are referred to as tag-
unaware. 802.1Q devices are referred to as tag-aware.
Prior to the adoption 802.1Q VLANs, port-based and MAC-based VLANs were in common use. These
VLANs relied upon a Port VLAN ID (PVID) to forward packets. A packet received on a given port would be assigned that port’s PVID and then be forwarded to the port that corresponded to the packet’s destination address (found in the switch’s forwarding table). If the PVID of the port that received the packet is different from the PVID of the port that is to transmit the packet, the switch will drop the packet.
Within the switch, different PVIDs mean different VLANs (remember that two VLANs cannot communicate without an external router). So, VLAN identification based upon the PVIDs cannot create
VLANs that extend outside a given switch (or switch stack).
Every physical port on a switch has a PVID. 802.1Q ports are also assigned a PVID, for use within the switch. If no VLANs are defined on the switch, all ports are then assigned to a default VLAN with a PVID equal to 1. Untagged packets are assigned the PVID of the port on which they were received.
Forwarding decisions are based upon this PVID, in so far as VLANs are concerned. Tagged packets are forwarded according to the VID contained within the tag. Tagged packets are also assigned a PVID, but the PVID is not used to make packet forwarding decisions, the VID is.
Tag-aware switches must keep a table to relate PVIDs within the switch to VIDs on the network. The switch will compare the VID of a packet to be transmitted to the VID of the port that is to transmit the packet. If the two VIDs are different, the switch will drop the packet. Because of the existence of the
PVID for untagged packets and the VID for tagged packets, tag-aware and tag-unaware network devices can coexist on the same network.
A switch port can have only one PVID, but can have as many VIDs as the switch has memory in its
VLAN table to store them.
Because some devices on a network may be tag-unaware, a decision must be made at each port on a tag-aware device before packets are transmitted – should the packet to be transmitted have a tag or
39
DES-3326 Layer 3 Fast Ethernet Switch User’s Guide not? If the transmitting port is connected to a tag-unaware device, the packet should be untagged. If the transmitting port is connected to a tag-aware device, the packet should be tagged.
Tagging and Untagging
Every port on an 802.1Q compliant switch can be configured as tagging or untagging.
Ports with tagging enabled will put the VID number, priority and other VLAN information into the header of all packets that flow into and out of it. If a packet has previously been tagged, the port will not alter the packet, thus keeping the VLAN information intact. The VLAN information in the tag can then be used by other 802.1Q compliant devices on the network to make packet forwarding decisions.
Ports with untagging enabled will strip the 802.1Q tag from all packets that flow into and out of those ports. If the packet doesn’t have an 802.1Q VLAN tag, the port will not alter the packet. Thus, all packets received by and forwarded by an untagging port will have no 802.1Q VLAN information.
(Remember that the PVID is only used internally within the switch). Untagging is used to send packets from an 802.1Q-compliant network device to a non-compliant network device.
Ingress Filtering
A port on a switch where packets are flowing into the switch and VLAN decisions must be made is referred to as an ingress port. If ingress filtering is enabled for a port, the switch will examine the VLAN information in the packet header (if present) and decide whether or not to forward the packet.
If the packet is tagged with VLAN information, the ingress port will first determine if the ingress port itself is a member of the tagged VLAN. If it is not, the packet will be dropped. If the ingress port is a member of the 802.1Q VLAN, the switch then determines if the destination port is a member of the
802.1Q VLAN. If it is not, the packet is dropped. If the destination port is a member of the 802.1Q
VLAN, the packet is forwarded and the destination port transmits it to its attached network segment.
If the packet is not tagged with VLAN information, the ingress port will tag the packet with its own PVID as a VID (if the port is a tagging port). The switch then determines if the destination port is a member of the same VLAN (has the same VID) as the ingress port. If it does not, the packet is dropped. If it has the same VID, the packet is forwarded and the destination port transmits it on its attached network segment.
This process is referred to as ingress filtering and is used to conserve bandwidth within the switch by dropping packets that are not on the same VLAN as the ingress port at the point of reception. This eliminates the subsequent processing of packets that will just be dropped by the destination port.
VLANs in Layer 2 Only Mode
The switch initially configures one VLAN, VID = 1, called the DEFAULT_VLAN. The factory default setting assigns all ports on the switch to the DEFAULT_VLAN.
Packets cannot cross VLANs if the switch is in Layer 2 Only mode. If a member of one VLAN wants to connect to another VLAN, the link must be through an external router.
When the switch is in Layer 2 Only mode, 802.1Q VLANs are supported.
If no VLANs are configured on the switch and the switch is in Layer 2 Only mode, then all packets will be forwarded to any destination port. Packets with unknown source addresses will be flooded to all ports. Broadcast and multicast packets will also be flooded to all ports.
A VLAN that does not have a corresponding IP interface defined for it, will function as a Layer 2 Only
VLAN – regardless of the Switch Operation mode.
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Layer 3-Based VLANs
Layer 3-based VLANs use network-layer addresses (subnet address for TCP/IP) to determine VLAN membership. These VLANs are based on layer 3 information, but this does not constitute a ‘routing’ function.
The DES-3326 allows an IP subnet to be configured for each 802.1Q VLAN that exists on the switch.
Even though a switch inspects a packet’s IP address to determine VLAN membership, no route calculation is performed, the RIP protocol is not employed, and packets traversing the switch are bridged using the Spanning Tree algorithm.
A switch that implements layer 3 (or ‘subnet’) VLANs without performing any routing function between these VLANs is referred to as performing ‘IP Switching’.
IP Addressing and Subnetting
This section gives basic information needed to configure your Layer 3 switch for IP routing. The information includes how IP addresses are broken down and how subnetting works. You will learn how to assign each interface on the router an IP address with a unique subnet.
Definitions
• IP Address – the unique number ID assigned to each host or interface on a network. IP addresses have the form xxx.xxx.xxx.xxx.
• Subnet – a portion of a network sharing a particular network address.
• Subnet mask – a 32-bit number used to describe which portion of a Network Address refers to the subnet and which portion refers to the host. Subnet masks have the form xxx.xxx.xxx.xxx.
• Interface – a network connection
• IP Interface – another name for subnet.
• Network Address – the resulting 32-bit number from a bitwise logical AND operation performed between an IP address and a subnet mask.
• Subnet Address – another name for network address.
IP Addresses
The Internet Protocol (IP) was designed for routing data between network sites. Later, it was adapted for routing between networks (referred to as “subnets”) within a site. The IP defines a way of generating a unique number that can be assigned each network in the internet and each of the computers on each of those networks. This number is called the IP address.
IP addresses use a “dotted decimal” notation. Here are some examples of IP addresses written in this format:
1. 210.202.204.205
2. 189.21.241.56
3. 125.87.0.1
This allows IP address to be written in a string of 4 decimal (base 10) numbers. Computers can only understand binary (base 2) numbers, and these binary numbers are usually grouped together in bytes, or eight bits. (A bit is a binary digit – either a “1” or a “0”). The dots (periods) simply make the IP
41
DES-3326 Layer 3 Fast Ethernet Switch User’s Guide address easier to read. A computer sees an IP address not as four decimal numbers, but as a long string of binary digits (32 binary digits or 32 bits, IP addresses are 32-bit addresses).
The three IP addresses in the example above, written in binary form are:
1. 11010010.11001010.11001100.11001101
2. 10111101.00010101.11110001.00111000
3. 01111101.01010111.00000000.00000001
The dots are included to make the numbers easier to read.
Eight binary bits are called a ‘byte’ or an ‘octet’. An octet can represent any decimal value between ‘0’
(00000000) and ‘255’ (11111111). IP addresses, represented in decimal form, are four numbers whose value is between ‘0’ to ‘255’. The total range of IP addresses are then:
Lowest possible IP address -
Highest possible IP address -
0.0.0.0
255.255.255.255
To convert decimal numbers to 8-bit binary numbers (and vice-versa), you can use the following chart:
Binary Octet Digit 2 7 2 6 2 5 2 4 2 3 2 2
Decimal Equivalent
Binary Number
128+64+32+16+8+4+2+1=
255
Table 5-4. Binary to Decimal Conversion
2 1 2
0
128 64 32 16 8 4 2 1
Each digit in an 8-bit binary number (an octet) represents a power of two. The left-most digit represents
2 raised to the 7 th power (2x2x2x2x2x2x2=128) while the right-most digit represents 2 raised to the 0 th power (any number raised to the 0 th power is equal to one, by definition).
IP addresses actually consist of two parts, one identifying the network and one identifying the destination (node) within the network.
The IP address discussed above is one part and a second number called the Subnet mask is the other part. To make this a bit more confusing, the subnet mask has the same numerical form as an IP address.
Address Classes
Address classes refer to the range of numbers in the subnet mask. Grouping the subnet masks into classes makes the task of dividing a network into subnets a bit easier.
There are 5 address classes. The first 4 bits in the IP address determine which class the IP address falls in.
• Class A addresses begin with 0xxx, or 1 to 126 decimal.
• Class B addresses begin with 10xx, or 128 to 191 decimal.
• Class C addresses begin with 110x, or 192 to 223 decimal.
• Class D addresses begin with 1110, or 224 to 239 decimal.
• Class E addresses begin with 1111, or 240 to 254 decimal.
Addresses beginning with 01111111, or 127 decimal, are reserved. They are used for internal testing on a local machine (called loopback). The address 127.0.0.1 can always be pinged from a local node because it forms a loopback and points back to the same node.
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DES-3326 Layer 3 Fast Ethernet Switch User’s Guide
Class D addresses are reserved for multicasting.
Class E Addresses are reserved for future use. They are not used for node addresses.
The part of the IP address that belongs to the network is the part that is ‘hidden’ by the ‘1’s in the subnet mask. This can be seen below:
• Class A NETWORK.node.node.node
• Class B NETWORK.NETWORK.node.node
• Class C NETWORK.NETWORK.NETWORK.node
For example, the IP address 10.42.73.210 is a Class A address, so the Network part of the address
(called the Network Address) is the first octet (10.x.x.x). The node part of the address is the last three octets (x.42.73.210).
To specify the network address for a given IP address, the node part is set to all “0”s. In our example,
10.0.0.0 specifies the network address for 10.42.73.210. When the node part is set to all “1”s, the address specifies a broadcast address. So, 10.255.255.255 is the broadcast address for the network
10.0.0.0.
Subnet Masking
A subnet mask can be applied to an IP address to identify the network and the node parts of the address. A bitwise logical AND operation between the IP address and the subnet mask results in the
Network Address.
For example:
Class A IP address
11111111.00000000.00000000.00000000 255.0.0.0 Class A Subnet Mask
00001010.00000000.00000000.00000000 10.0.0.0 Network Address
The Default subnet masks are:
• Class A – 11111111.00000000.00000000.00000000
• Class B – 11111111.11111111.00000000.00000000
• Class C – 1111111.11111111.11111111.00000000
255.0.0.0
255.255.0.0
255.255.255.0
Additional bits can be added to the default subnet mask for a given Class to further subnet a network.
When a bitwise logical AND operation is performed between the subnet mask and the IP address, the result defines the Subnet Address.
Some restrictions apply to subnet addresses. Addresses of all “0”s and all “1”s are reserved for the local network (when a host does not know it’s network address) and for all hosts on the network (the broadcast address). This also applies to subnets. A subnet address cannot be all “0”s or all “1”s. A 1bit subnet mask is also not allowed.
Calculating the Number of Subnets and Nodes
To calculate the number of subnets and nodes, use the formula (2 n – 2) where n = the number of bits in either the subnet mask or the node portion of the IP address. Multiplying the number of subnets by the number of nodes available per subnet gives the total number of nodes for the entire network.
Example
00001010.00101010.01001001.11010010 10.42.73.210 Class A IP address
00001010.00100000.00000000.00000000 10.32.0.0 Network Address
00001010.00101010.11111111.11111111 10.32.255.255 Broadcast Address
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DES-3326 Layer 3 Fast Ethernet Switch User’s Guide
This example uses an 11-bit subnet mask. (There are 3 additional bits added to the default Class A subnet mask). So the number of subnets is:
2
3
– 2 = 8 – 2 = 6
Subnets of all “0”s and all “1”s are not allowed, so 2 subnets are subtracted from the total.
The number of bits used in the node part of the address is 24 – 3 = 21 bits, so the total number of nodes is:
2
21
– 2 = 2,097,152 – 2 = 2,097,150
Multiplying the number of subnets times the number of nodes gives 12,582,900 possible nodes.
Note that this is less than the 16,777,214 possible nodes that an unsubnetted class A network would have.
Subnetting reduces the number of possible nodes for a given network, but increases the segmentation of the network.
Classless InterDomain Routing – CIDR
Under CIDR, the subnet mask notation is reduced to a simplified shorthand. Instead of specifying all of the bits of the subnet mask, it is simply listed as the number of contiguous “1”s (bits) in the network portion of the address. Look at the subnet mask of the above example in binary -
11111111.11100000.00000000.00000000 – and you can see that there are 11 “1”s or 11 bits used to mask the network address from the node address. Written in CIDR notation this becomes:
10.32.0.0/11
# of
Bits
Subnet Mask
19 255.255.255.2
24
20 255.255.255.2
40
21 255.255.255.2
48
22 255.255.255.2
52
CID
R
Nota tion
# of
Subnets
6 255.252.0.0 /14
/28 104857
4
/29 209715
0
/30 419430
2
# of Hosts
4194302
2097150
4 255.240.0.0 /12 1048574
5 255.248.0.0 /13 524286
262142
10 255.255.192.0 /18 1022 16382
11 255.255.224.0 /19 2046 8190
12 255.255.240.0 /20 4094 4094
13 255.255.248.0 /21 8190 2046
14 255.255.252.0 /22 16382 1022
15 255.255.254.0 /23 32766 510
16 255.255.255.0 /24 65534 254
/25 131070 126 17 255.255.255.1
28
18 255.255.255.1
92
/26 262142 62
/27 525286 30
Total Hosts
8388604
12582900
14680036
15728580
16252804
16514820
16645636
16710660
16742404
16756740
16760836
16756740
16742404
16710660
16645636
16514820
16252804
15728580
14 14680036
6 12582900
2 8388604
Table 5-5. Class A Subnet Masks
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DES-3326 Layer 3 Fast Ethernet Switch User’s Guide
# of
Bits
Subnet Mask CIDR
Notation
# of
Subnets
2 255.255.192 /18 2
3 255.255.224.0 /19 6
4 255.255.240.0 /20 14
5 255.255.248.0 /21 30
# of
Hosts
Total
Hosts
16382 32764
8190 49140
4094 57316
2046 61380
6 255.255.252.0 /22 62 1022 63364
7 255.255.254.0 /23 126 510 64260
8 255.255.255.0 /24 254 254 64516
9 255.255.255.128 126 64260
10 255.255.255.192 1022 62 63364
11 255.255.255.224 2046 30
12 255.255.255.240 4094 14
13 255.255.255.248 8190 6
14 255.255.255.252 16382 2
61380
57316
49140
32764
Table 5-6. Class B Subnet Masks
# of
Bits
Subnet Mask CIDR
Notation
# of
Subnets
# of
Hosts
62
30
14
6
2
Table 5-7. Class C Subnet Masks
Total
Hosts
124
180
196
180
124
Setting up IP Interfaces
The Layer 3 switch allows ranges of IP addresses (OSI layer 3) to be assigned to VLANs (OSI layer 2).
Each VLAN must be configured prior to setting up the corresponding IP interface. An IP addressing scheme must then be established, and implemented when the IP interfaces are set up on the switch.
An example is presented below:
VLAN Name VID Switch Ports
System (default)
Engineering
Marketing
Finance
Sales
3
4
1
2
5
5, 6, 7, 8, 21, 22, 23, 24
9, 10, 11, 12
13, 14, 15, 16
17, 18, 19, 20
1, 2, 3, 4
Table 5-8. VLAN Example – Assigned Ports
In this case, 6 IP interfaces are required, so a CIDR notation of 10.32.0.0/11 (or a 11-bit) addressing scheme will work. This addressing scheme will give a subnet mask of
11111111.11100000.00000000.00000000 (binary) or 255.224.0.0 (decimal).
Using a 10.xxx.xxx.xxx IP address notation, the above example would give 6 network addresses and 6 subnets.
Any IP address from the allowed range of IP addresses for each subnet can be chosen as an IP address for an IP interface on the switch.
For this example, we have chosen the next IP address above the network address:
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DES-3326 Layer 3 Fast Ethernet Switch User’s Guide
VLAN Name VID Network Address IP Address
System (default) 1 10.32.0.0 10.32.0.1
Engineering 2 10.64.0.0 10.64.0.1
Table 5-9. VLAN Example – Assigned IP Addresses
The 6 IP interfaces, each with an IP address (listed in the table above), and a subnet mask of
255.224.0.0 can be entered into the Setup IP Interface menu.
Layer 3-Based VLANs
Layer 3-based VLANs use network-layer addresses (subnet address for TCP/IP) to determine VLAN membership. These VLANs are based on layer 3 information, but this does not constitute a ‘routing’ function.
The DES-3326 allows an IP subnet to be configured for each 802.1Q VLAN that exists on the switch.
Even though a switch inspects a packet’s IP address to determine VLAN membership, no route calculation is performed, the RIP protocol is not employed, and packets traversing the switch are bridged using the Spanning Tree algorithm.
A switch that implements layer 3 (or ‘subnet’) VLANs without performing any routing function between these VLANs is referred to as performing ‘IP Switching’.
Internet Protocols
This is a brief introduction to the suite of Internet Protocols frequently referred to as TCP/IP. It is intended to give the reader a reasonable understanding of the available facilities and some familiarity with terminology. It is not intended to be a complete description.
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DES-3326 Layer 3 Fast Ethernet Switch User’s Guide
Protocol Layering
The Internet Protocol (IP) divides the tasks necessary to route and forward packets across networks by using a layered approach. Each layer has clearly defined tasks, protocol, and interfaces for communicating with adjacent layers, but the exact way these tasks are accomplished is left to individual software designers. The Open Systems Interconnect (OSI) seven-layer model has been adopted as the reference for the description of modern networking, including the Internet.
A diagram of the OSI model is shown below (note that this is not a complete listing of the protocols contained within each layer of the model):
Figure 5-11. OSI Seven Layer Network Model
Each layer is a distinct set of programs executing a distinct set of protocols designed to accomplish some necessary tasks. They are separated from the other layers within the same system or network, but must communicate and interoperate. This requires very well-defined and well-known methods for transferring messages and data. This is accomplished through the protocol stack.
Protocol layering as simply a tool for visualizing the organization of the necessary software and hardware in a network. In this view, Layer 2 represents switching and Layer 3 represents routing.
Protocol layering is actually a set of guidelines used in writing programs and designing hardware that delegate network functions and allow the layers to communicate. How these layers communicate within a stack (for example, within a given computer) is left to the operating system programmers.
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DES-3326 Layer 3 Fast Ethernet Switch User’s Guide
Figure 5-12. The Protocol Stack
Between two protocol stacks, members of the same layer are known as peers and communicate by wellknown (open and published) protocols. Within a protocol stack, adjacent layers communicate by an internal interface. This interface is usually not publicly documented and is frequently proprietary. It has some of the same characteristics of a protocol and two stacks from the same software vendor may communicate in the same way. Two stacks from different software vendors (or different products from the same vendor) may communicate in completely different ways. As long as peers can communicate and interoperate, this has no impact on the functioning of the network.
The communication between layers within a given protocol stack can be both different from a second stack and proprietary, but communication between peers on the same OSI layer is open and consistent.
A brief description of the most commonly used functional layers is helpful to understand the scope of how protocol layering works.
Layer 1
This is referred to as the physical layer. It handles the electrical connections and signaling required to make a physical link from one point in the network to another. It is on this layer that the unique Media
Access Control (MAC) address is defined.
Layer 2
This layer, commonly called the switching layer, allows end station addressing and the establishment of connections between them.
Layer 2 switching forwards packets based on the unique MAC address of each end station and offers high-performance, dedicated-bandwidth of Fast or Gigibit Ethernet within the network.
Layer 2 does not ordinarily extend beyond the intranet. To connect to the Internet usually requires a router and a modem or other device to connect to an Internet Service Provider’s WAN. These are Layer
3 functions.
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DES-3326 Layer 3 Fast Ethernet Switch User’s Guide
Layer 3
Commonly referred to as the routing layer, this layer provides logical partitioning of networks
(subnetting), scalability, security, and Quality of Service (QoS).
The backbone of the Internet is built using Layer 3 functions. IP is the premier Layer 3 protocol.
IP is itself, only one protocol in the IP protocol suite. More extensive capabilities are found in the other protocols of the IP suite. For example; the Domain Name System (DNS) associates IP addresses with text names, the Dynamic Host Configuration Protocol (DHCP) eases the administration of IP addresses, and routing protocols such as the Routing Information Protocol (RIP), the Open Shortest Path First
(OSPF), and the Border Gateway Protocol (BGP) enable Layer 3 devices to direct data traffic to the intended destination. IP security allows for authentication and encryption. IP not only allows for userto-user communication, but also for transmission from point-to-multipoint (known as IP multicasting).
Layer 4
This layer, known as the transport layer, establishes the communication path between user applications and the network infrastructure and defines the method of communicating. TCP and UDP are well-known protocols in the transport layer. TCP is a “connection-oriented” protocol, and requires the establishment of parameters for transmission prior to the exchange of data. Web technology is based on TCP. UDP is “connectionless” and requires no connection setup. This is important for multicast traffic, which cannot tolerate the overhead and latency of TCP. TCP and UDP also differ in the amount of error recovery provided and whether or not it is visible to the user application. Both TCP and
UDP are layered on IP, which has minimal error recovery and detection. TCP forces retransmission of data that was lost by the lower layers, UDP does not.
Layer 7
This layer, known as the application layer, provides access to either the end user application software such as a database. Users communicate with the application, which in turn delivers data to the transport layer. Applications do not usually communicate directly with lower layers. They are written to use a specific communication library, like the popular WinSock library.
Software developers must decide what type of transport mechanism is necessary. For example, Web access requires reliable, error-free access and would demand TCP. Multimedia, on the other hand, requires low overhead and latency and commonly uses UDP.
TCP/IP
The TCP/IP protocol suite is a set of protocols that allow computers to share resources across a network. TCP and IP are only two of the Internet suite of protocols, but they are the best known and it has become common to refer the entire family of Internet protocols as TCP/IP.
TCP/IP is a layered set of protocols. An example, such as sending e-mail, can illustrate this. There is first a protocol for sending and receiving e-mail. This protocol defines a set of commands to identify the sender, the recipient, and the content of the e-mail. The e-mail protocol will not handle the actual communication between the two computers as this is done by TCP/IP. TCP/IP handles the actual sending and receiving of the packets that make up the e-mail exchange.
TCP makes sure the e-mail commands and messages are received by the appropriate computers. It keeps track of what is sent and what is received, and retransmits any packets that are lost or dropped.
TCP also handles the division of large messages into several Ethernet packets, and makes sure these packets are received and reassembled in the correct order.
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DES-3326 Layer 3 Fast Ethernet Switch User’s Guide
Because these functions are required by a large number of applications, they are grouped into a single protocol, rather than being the part of the specifications for just sending e-mail. TCP is then a library of routines that application software can use when reliable network communications are required.
IP is also a library of routines, but with a more general set of functions. IP handles the routing of packets from the source to the destination. This may require the packets to traverse many different networks. IP can route packets through the necessary gateways and provides the functions required for any user on one network to communicate with any user on another connected network.
The communication interface between TCP and IP is relatively simple. When IP received a packet, it does not know how this packet is related to others it has sent (or received) or even which connection the packet is part of. IP only knows the address of the source and the destination of the packet, and it makes its best effort to deliver the packet to its destination.
The information required for IP to do its job is contained in a series of octets added to the beginning of the packet called headers. A header contains a few octets of data added to the packet by the protocol in order to keep track of it.
Other protocols on other network devices can add and extract their own headers to and from packets as they cross networks. This is analogous to putting data into an envelope and sending the envelope to a higher-level protocol, and having the higher-level protocol put the entire envelope into it’s own, larger envelope. This process is referred to as encapsulation.
Many levels of encapsulation are required for a packet to cross the Internet.
Packet Headers
TCP
Most data transmissions are much longer that a single packet. The data must then be divided up among a series of packets. These packets must be transmitted, received and then reassembled into the original data. TCP handles these functions.
TCP must know how large a packet the network can process. To do this, the TCP protocols at each end of a connection state how large a packet they can handle and the smaller of the two is selected.
The TCP header contains at least 20 octets. The source and destination TCP port numbers are the most important fields. These specify the connection between two TCP protocols on two network devices.
The header also contains a sequence number that is used to ensure the packets are received in the correct order. The packets are not numbered, but rather the octets the packets contain are. If there are
100 octets of data in each packet, the first packet is numbered 0, the second 100, the third 200, etc.
To insure that the data in a packet is received uncorrupted, TCP adds the binary value of all the octets in the packet and writes the sum in the checksum field. The receiving TCP recalculates the checksum and if the numbers are different, the packet is dropped.
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DES-3326 Layer 3 Fast Ethernet Switch User’s Guide
Figure 5-13. TCP Packet Header
When packets have been successfully received, TCP sends an acknowledgement. This is simply a packet that has the acknowledgement number field filled in.
An acknowledgement number of 1000 indicates that all of the data up to octet 1000 has been received.
If the transmitting TCP does not receive an acknowledgement in a reasonable amount of time, the data is resent.
The window field controls the amount of data being sent at any one time. It would require too much time and overhead to acknowledge each packet received. Each end of the TCP connection declares how much data it is able to receive at any one time by writing this number of octets in the window field.
The transmitting TCP decrements the number in the window field and when it reaches zero, the transmitting TCP stops sending data. When the receiving TCP can accept more data, it increases the number in the window field. In practice, a single packet can acknowledge the receipt of data and give permission for more data to be sent.
IP
TCP sends its packets to IP with the source and destination IP addresses. IP is only concerned with these IP addresses. It is not concerned with the contents of the packet or the TCP header.
IP finds a route for the packet to get to the other end of the TCP connection. IP adds its own header to the packet to accomplish this.
The IP header contains the source and destination addresses, the protocol number, and another checksum.
The protocol number tells the receiving IP which protocol to give the packet to. Although most IP traffic uses TCP, other protocols can be used (such as UDP).
The checksum is used by the receiving IP in the same way as the TCP checksum.
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DES-3326 Layer 3 Fast Ethernet Switch User’s Guide
Figure 5-14. IP Packet Header
The flags and fragment offset are used to keep track of packets that must be divided among several smaller packets to cross networks for which they are too large.
The Time-to-Live (TTL) is the number of gateways the packet is allowed to cross between the source and destination. This number is decremented by one when the packet crosses a gateway and when the TTL reaches zero, the packet is dropped. This helps reduce network traffic if a loop develops.
Ethernet
Every active Ethernet device has its own Ethernet address (commonly called the MAC address) assigned to it by the manufacturer. Ethernet uses 48 bit addresses.
The Ethernet header is 14 octets that include the source and destination MAC address and a type code.
There is no relationship between the MAC address of a network node and its IP address. There must be a database of Ethernet addresses and their corresponding IP addresses.
Different protocol families can be in use on the same network. The type code field allows each protocol family to have its own entry.
A checksum is calculated and when the packet is received, the checksum is recalculated. If the two checksums are different, the packet is dropped.
Figure 5-15. Ethernet Packet Header
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When a packet is received, the headers are removed. The Ethernet Network Interface Card (NIC) removes the Ethernet header and checks the checksum. It then looks at the type code. If the type code is for IP, the packet is given to IP. IP then removes the IP header and looks at its protocol field. If the protocol field is TCP, the packet is sent to TCP. TCP then looks at the sequence number and uses this number and other data from the headers to reassemble the data into the original file.
TCP and UDP Well-Known Ports
Application protocols run ‘on top of’ TCP/IP. When an application wants to send data or a message, it gives the data to TCP. Because TCP and IP take care of the networking details, the application can look at the network connection as a simple data stream.
To transfer a file across a network using the File Transfer Protocol (FTP), a connection must first be established. The computer requesting the file transfer must connect specifically to the FTP server on the computer that has the file.
This is accomplished using sockets. A socket is a pair of TCP port numbers used to establish a connection from one computer to another. TCP uses these port numbers to keep track of connections.
Specific port numbers are assigned to applications that wait for requests. These port numbers are referred to as ‘well-known’ ports.
TCP will open a connection to the FTP server using some random port number, 1234 for example, on the local computer. TCP will specify port 21 for the FTP server. Port 21 is the well-known port number for FTP servers. Note that there are two different FTP programs running in this example – an FTP client that requests the file to be transferred, and an FTP server that sends the file to the FTP client. The FTP server accepts commands from the client, so the FTP client must know how to connect to the server
(must know the TCP port number) in order to send commands. The FTP Server can use any TCP port number to send the file, so long as it is sent as part of the connection setup.
A TCP connection is then described by a set of four numbers – the IP address and TCP port number for the local computer, and the IP address and TCP port number for the remote computer. The IP address is in the IP header and the TCP port number is in the TCP header.
No two TCP connection can have the same set of numbers, but only one number needs to be different.
It is possible, for example, for two users to send files to the same destination at the same time. This could give the following connection numbers:
Connection 1 10.42.73.23, 10.128.12.1 1234, 21
Connection 2 10.42.73.23, 10.128.12.1 1235, 21
The same computers are making the connections, so the IP addresses are the same. Both computers are using the same well-known TCP port for the FTP server. The local FTP clients are using different
TCP port numbers.
FTP transfers actually involve two different connections. The connection begins by the FTP sending commands to send a particular file. Once the commands are sent, a second connection is opened for the actual data transfer. Although it is possible to send data on the same connection, it is very convenient for the FTP client to be able to continue to send commands (such as ‘stop sending this file’).
UDP and ICMP
There are many applications that do not require long messages that cannot fit into a single packet.
Looking up computer names is an example. Users wanting to make connections to other computers will usually use a name rather than the computer’s IP or MAC address. The user’s computer must be able
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DES-3326 Layer 3 Fast Ethernet Switch User’s Guide to determine the remote computer’s address before a connection can be made. A designated computer on the network will contain a database of computer names and their corresponding IP and MAC addresses. The user’s computer will send a query to the name database computer, and the database computer will send a response. Both the query and the response are very short. There is no need to divide the query or response between multiple packets, so the complexity of TCP is not required. If there is no response to the query after a period of time, the query can simply be resent.
The User Datagram Protocol (UDP) is designed for communications that do not require division among multiple packets and subsequent reassembly. UDP does not keep track of what is sent.
UDP uses port numbers in a way that is directly analogous to TCP. There are well-known UDP port numbers for servers that use UDP.
Figure 5-16. Ethernet Packet Header
The UDP header is shorter than a TCP header. UDP also uses a checksum to verify that data is received uncorrupted.
The Internet Control Message Protocol (ICMP) is also a simplified protocol used for error messages and messages used by TCP/IP. ICMP, like UDP, processes messages that will fit into a single packet. ICMP does not, however use ports because its messages are processed by the network software.
The Domain Name System
Computer users usually prefer to use text names for computers they may want to open a connection with. Computers themselves, require 32 bit IP addresses. Somewhere, a database of network devices’ text names and their corresponding IP addresses must be maintained.
The Domain Name System (DNS) is used to map names to IP addresses throughout the Internet and has been adapted for use within intranets.
For two DNS servers to communicate across different subnets, the DNS Relay of the DES-3326 must be used. The DNS servers are identified by IP addresses.
Mapping Domain Names to Addresses
Name-to-address translation is performed by a program called a Name server. The client program is called a Name resolver. A Name resolver may need to contact several Name servers to translate a name to an address.
The Domain Name System (DNS) servers are organized in a somewhat hierarchical fashion. A single server often holds names for a single network, which is connected to a root DNS server – usually maintained by an ISP.
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Domain Name Resolution
The domain name system can be used by contacting the name servers one at a time, or by asking the domain name system to do the complete name translation. The client makes a query containing the name, the type of answer required, and a code specifying whether the domain name system should do the entire name translation, or simply return the address of the next DNS server if the server receiving the query cannot resolve the name.
When a DNS server receives a query, it checks to see if the name is in its subdomain. If it is, the server translates the name and appends the answer to the query, and sends it back to the client. If the DNS server cannot translate the name, it determines what type of name resolution the client requested. A complete translation is called recursive resolution and requires the server to contact other DNS servers until the name is resolved. Iterative resolution specifies that if the DNS server cannot supply an answer, it returns the address of the next DNS server the client should contact.
Each client must be able to contact at least one DNS server, and each DNS server must be able to contact at least one root server.
The address of the machine that supplies domain name service is often supplied by a DHCP or BOOTP server, or can be entered manually and configured into the operating system at startup.
DHCP Servers
The Dynamic Host Configuration Protocol (DHCP) is used to dynamically assign a TCP/IP network configuration to network devices and computers on the network. It also ensures that IP address conflicts do not occur.
IP addresses are assigned from a pool of free addresses. Each IP address assigned has a ‘lease’ and a
‘lease expiration period’. The lease must be periodically renewed. If the lease is expires, the IP address is returned to the pool of available IP addresses.
Usually, it is a network policy to assign the same IP address to a given network device or computer each time.
If the IP address lease expires, the network device sends a message to the DHCP server requesting a lease renewal. The DHCP server can send an acknowledgement containing a new lease and updated configuration information.
If an IP address lease cannot be renewed, the network device or computer sends a request to all local
DHCP servers attempting to renew the lease. If the DHCP returns a negative acknowledgement, the network device must release its TCP/IP configuration and reinitialize.
When a new TCP/IP configuration is received from a DHCP server, the network device checks for a possible IP address conflict by sending an Address Resolution Protocol (ARP) request that contains its new IP address.
For two DHCP servers to communicate across different subnets, the BOOTP/DHCP Relay of the
DES-3326 must be used. The DHCP servers are identified by IP addresses.
IP Routing
IP handles the task of determining how packets will get from their source to their destination. This process is referred to as routing.
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For IP to work, the local system must be attached to a network. It is safe to assume that any system on this network can send packets to any other system, but when packets must cross other networks to reach a destination on a remote network, these packets must be handled by gateways (also called routers).
Gateways connect a network with one or more other networks. Gateways can be a computer with two network interfaces or a specialized device with multiple network interfaces. The device is designed to forward packets from one network to another.
IP routing is based on the network address of the destination IP address. Each computer has a table of network addresses. For each network address, a corresponding gateway is listed. This is the gateway to use to communicate with that network. The gateway does not have to be directly connected to the remote network, it simply needs to be the first place to go on the way to the remote network.
Before a local computer sends a packet, it first determines whether the destination address is on the local network. If it is, the packet can be sent directly to the remote device. If it is not, the local computer looks for the network address of the destination and the corresponding gateway address. The packet is then sent to the gateway leading to the remote network. There is often only one gateway on a network.
A single gateway is usually defined as a default gateway, if that gateway connects the local network to a backbone network or to the Internet. This default gateway is also used whenever no specific route is found for a packet, or when there are several gateways on a network.
Local computers can use default gateways, but the gateways themselves need a more complete routing table to be able to forward packets correctly. A protocol is required for the gateways to be able to communicate between themselves and to keep their routing tables updated.
Packet Fragmentation and Reassembly
TCP/IP can be used with many different types of networks, but not all network types can handle the same length packets.
When IP is transmitting large files, large packets are much more efficient than small ones. It is preferable to use the largest possible packet size, but still be able to cross networks that require smaller packets.
To do this, IP can ‘negotiate’ packet size between the local and remote ends of a connection. When an IP connection is first made, the IPs at both ends of the connection state the largest packet they can handle. The smaller of the two is selected.
When an IP connection crosses multiple networks, it is possible that one of the intermediate networks has a smaller packet size limit than the local or remote network. IP is not able to determine the maximum packet size across all of the networks that may make up the route for a connection. IP has, therefore, a method to divide packets into multiple, smaller packets to cross such networks. This division of large packets into smaller packets is referred to as fragmentation.
A field in the TCP header indicates that a packet has been fragmented, and other information aids in the reassembly of the packets into the original data.
Gateways that connect networks of different packet size limits split the large packets into smaller ones and forward the smaller packets on their attached networks.
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ARP
The Address Resolution Protocol (ARP) determines the MAC address and IP address correspondence for a network device.
A local computer will maintain an ARP cache that is a table of MAC addresses and the corresponding IP addresses. Before a connection with another computer is made, the local computer first checks its ARP cache to determine whether the remote computer has an entry. If it does, the local computer reads the remote computer’s MAC address and writes it into the destination field of the packets to be sent.
If the remote computer does not have an ARP cache entry, the local computer must send an ARP request and wait for a reply.
When the local computer receives the ARP reply packet, the local ARP reads the IP MAC address pair, and then checks the ARP cache for this entry. If there is an entry, it is updated with the new information. If there is no entry, a new entry is made.
There are two possible cases when an ARP packet is received by a local computer. First, the local computer is the target of the request. If it is, the local ARP replies by sending its MAC IP address pair back to the requesting system. Second, if the local computer is not the target of the request, the packet is dropped.
Multicasting
Multicasting is a group of protocols and tools that enable a single source point to send packets to groups of multiple destination points with persistent connections that last for some amount of time.
The main advantage to multicasting is a decrease in the network load compared to broadcasting.
Multicast Groups
Class D IP addresses are assigned to a group of network devices that comprise a multicast group. The four most significant four bits of a Class D address are set to “1110”. The following 28 bits is referred to as the ‘multicast group ID’. Some of the range of Class D addresses are registered with the Internet
Assigned Numbers Authority (IANA) for special purposes. For example, the block of multicast addresses ranging from 224.0.0.1 to 224.0.0.225 is reserved for use by routing protocols and some other low-level topology discovery and maintenance protocols.
Figure 5-17. Class D Multicast Address
Some of the reserved IP multicast addresses are as follows:
Address Assignment
224.0.0.0
224.0.0.1
Base Address (reserved)
All Systems on this subnet
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224.0.0.2
224.0.0.3
224.0.0.4
224.0.0.5
224.0.0.6
224.0.0.7
224.0.0.8
224.0.0.9
224.0.0.10
224.0.0.11
224.0.0.12
224.0.0.13
224.0.0.14
224.0.0.15
224.0.0.16
224.0.0.17
224.0.0.18
224.0.0.19 through
224.0.0.225
224.0.0.21
All Routers on this subnet
Unassigned
DVMRP Routers
OSPF IGP Routers
OSPF IGP Designated Routers
ST Routers
ST Hosts
All RIP2 Routers
All IGRP Routers
Mobile Agents
DHCP Servers and Relay Agents
All PIM Routers
RSVP Encapsulation
All CBT Routers
Designated Sbm
All Sbms
VRRP
Unassigned
DVMRP on MOSPF
Table 5-10. Reserved Multicast Address Assignment
Internet Group Management Protocol (IGMP)
End users that want to receive multicast packets must be able to inform nearby routers that they want to become a multicast group member of the group these packets are being sent to. The Internet Group
Management Protocol (IGMP) is used by multicast routers to maintain multicast group membership.
IGMP is also used to coordinate between multiple multicast routers that may be present on a network by electing one of the multicast routers as the ‘querier’. This router then keep track of the membership of multicast groups that have active members on the network. IGMP is used to determine whether the router should forward multicast packets it receives to the subnetworks it is attached to or not. A multicast router that has received a multicast packet will check to determine if there is at least one member of a multicast group that has requested to receive multicast packets from this source. If there is one member, the packet is forwarded. If there are no members, the packet is dropped.
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IGMP Versions 1 and 2
Users that want to receive multicast packets need to be able to join and leave multicast groups. This is accomplished using IGMP.
Figure 5-18. IGMP Message Format
The IGMP Type codes are shown below:
0x1
1
0x1
6
0x1
7
0x1
2
Type Meaning
0x11 Membership Query (if Group Address is 0.0.0.0)
Specific Group Membership Query (if Group Address is Present)
Membership Report (version 2)
Leave a Group (version 2)
Membership Report (version 1)
Table 5-11. IGMP Type Codes
Multicast routers use IGMP to manage multicast group memberships:
• An IGMP “report” is sent by a user’s computer to join a group
• IGMP version 1 does not have an explicit ‘leave’ message. Group members have an expiration timer, and if this timer expires before a query response is returned, the member is dropped from the group.
• IGMP version 2 introduces an explicit “leave” report. When a user wants to leave a group, this report is sent to the multicast router (for IGMP version 2).
• Multicast routers send IGMP queries (to the all-hosts group address: 224.0.0.1) periodically to see whether any group members exist on their subnetworks. If there is no response from a particular group, the router assumes that there are no group members on the network, and multicast packets are not forwarded.
The TTL field of query messages is set to 1 so that the queries do not get forwarded to other subnetworks.
IGMP version 2 introduces a few extensions to IGMP version 1 such as, the election of a single multicast querier for each network, explicit ‘leave’ reports, and queries that are specific to a particular multicast group.
The router with the lowest IP address is elected as the querier. The explicit group leave message is added to decrease latency, and routers can ask for membership reports from a particular multicast group ID.
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The transition states a host will go through to join or leave a multicast group are shown in the diagram below.
Figure 5-19. IGMP State Transitions
Multicast Routing Algorithms
An algorithm is not a program. An algorithm is a statement of how a problem can be solved. A program is written to implement an algorithm.
Multicast packets are delivered by constructing multicast trees where the multicast router is the trunk, the branches are the various subnetworks that may be present, and the leaves are end recipients of the multicast packets. Several algorithms have been developed to construct these trees and to prune branches that have no active mulitcast group members.
Flooding
The simplest algorithm for the delivery of multicast packets is for the multicast router to forward a multicast packet to all interfaces. This is referred to as flooding. An equally simple refinement of flooding is to have the router check to determine if a given multicast packet has been received before (in a certain amount of time). If it has, then the packet does not need to be forwarded at all and can be dropped. If the packet is being received for the first time, it should be flooded to all interfaces, except the interface on which it was received. This will ensure that all routers on the network will receive at least one copy of the multicast packet.
There are some obvious disadvantages to this simple algorithm. Flooding duplicates a lot of packets and uses a lot of network bandwidth. A multicast router must also keep a record of the multicast packets it has received (for a period of time) to determine if a given packet has been previously received.
So flooding uses a lot of router memory.
Multicast Spanning Trees
A multicast delivery tree that spans the entire network with a single active link between routers (or subnetwork) is called a multicast spanning tree. Links (or branches) are chosen such that there is only one active path between any two routers. When a router receives a multicast packet, it forwards the
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Multicast spanning trees do not use group membership information when deciding to forward or drop a given multicast packet.
Reverse Path Broadcasting (RPB)
The Reverse Path Broadcasting (RPB) algorithm is an enhancement of the multicast spanning tree algorithm. RPB constructs a spanning tree for each multicast source. When the router receives a multicast packet, it then checks to determine if the packet was received on the shortest path back from the router to the source. If the packet was received on the shortest path back to the source, the packet is forwarded on all links except the link on which the packet was received. If the packet was not received on the shortest link back to the source, the packet is dropped.
If a link-state routing protocol is in use, RPB on a local router can determine if the path from the source through the local router to an immediately neighboring router. If it is not, the packet will be dropped at the next router and the packet should not be forwarded.
If a distance-vector routing protocol is in use, a neighboring router can either advertise its previous hop for the source as part of its routing update messages. This will ‘poison-reverse’ the route (or have the local router prune the branch from the multicast source to the neighboring router because the neighboring router has a better route from the source to the next router or subnetwork).
Since multicast packets are forwarded through the shortest route between source and destination, RPB is fast. A given router also does not need information about the entire spanning tree, nor does it need a mechanism to stop the forwarding of packets.
RPB does not use multicast group membership information in its forwarding decisions.
Reverse Path Multicasting (RPM)
Reverse Path Multicasting (RPM) introduces an enhancement to RPB – an explicit method to prune branches of the spanning tree that have on active multicast group members for the source. RPM constructs a tree that spans only subnetworks with multicast group member and routers along the shortest path between the source and the destinations.
When a multicast router receives a multicast packet, it is forwarded using the RPB constructed spanning tree. Subsequent routers in the tree that have no active path to another router are referred to as leaf routers. If the multicast packet if forwarded to a leaf router that has no active multicast group members for the source, the leaf router will send a prune message to the previous router. This will remove the leaf router’s branch from the spanning tree, and no more multicast packets (from that source) will be forwarded to it. Prune messages have a TTL equal to one, so they can be sent only one hop (one router) back toward the source. If the previous router receives prune messages from all of its branch and leaf routers, the previous router will then send it’s own prune message back one router toward the multicast source, and the process will repeat. In this way, multicast group membership information can be used to prune the spanning tree between a given multicast source and the corresponding multicast group.
Since the membership of any given multicast group can change and the network topology can also change, RPM periodically removes all of the prune information it has gathered from its memory, and the entire process repeats. This gives all subsequent routers on the network a chance to receive multicast packets from all multicast sources on the network. It also gives all users a chance to join a given multicast group.
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Multicast Routing Protocols
This section contains an overview of two multicast routing protocols – Distance Vector Multicast
Routing Protocol (DVMRP), and Protocol Independent Multicast-Dense Mode
(PIM-DM). The most commonly used routing protocol (not a multicast routing protocol), the Routing
Information Protocol, is discussed in a later section.
Distance Vector Multicast Routing Protocol (DVMRP)
The Distance Vector Multicast Routing Protocol (DVMRP) was derived from the Routing Information
Protocol (RIP) with the introduction of multicast delivery trees constructed from information about the
‘distance’ from the local router back toward the multicast source. DVMRP uses an RPM algorithm to construct its multicast delivery trees.
The first multicast packet received by a multicast router using DVMRP is flooded to all interfaces except the one on which the packet was received. Subsequent prune messages are used to prune branches of the delivery tree that are either not on the shortest path back to the multicast source, or that have no active multicast group members. A ‘graft’ message is added that allows a previously pruned branch of the multicast delivery tree to be reactivated. This allows for lower latency when a leaf router adds a new member to a multicast membership group. Graft messages are forwarded one hop (one router) back at a time toward a multicast source until they reach a router that is on an active branch of the multicast delivery tree.
If there is more than one multicast router on a network, the one that has the shortest path back to the multicast source is elected to forward multicast packets from that source. All other routers will discard multicast packets from that source. If two multicast routers on a network have the same distance back to a multicast source, the router with the lowest IP address is elected.
DVMRP also supports tunnel interfaces, where two multicast routers are connected through a router that cannot process multicast packets. This allows multicast packets to cross networks with routers that are not multicast-aware.
Protocol-Independent Multicast – Dense Mode
There are two protocols in Protocol Independent Multicast (PIM), Protocol Independent Multicast-Dense
Mode (PIM-DM) which is used when the multicast destinations are closely spaced, and Protocol
Independent Multicast-Sparse Mode (PIM-SM) which is used when the multicast destinations are spaced further apart. PIM-DM is most commonly implemented in an intranetwork (LAN) where the distance between users is minimal.
Routing Protocols
Routing Information Protocol (RIP)
The Routing Information Protocol is a distance-vector routing protocol. There are two types of network devices running RIP – active and passive. Active devices advertise their routes to others through RIP messages, while passive devices listen to these messages. Both active and passive routers update their routing tables based upon RIP messages that active routers exchange. Only routers can run RIP in the active mode.
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Every 30 seconds, a router running RIP broadcasts a routing update containing a set of pairs of network addresses and a distance (represented by the number of hops or routers between the advertising router and the remote network). So, the vector is the network address and the distance is measured by the number of routers between the local router and the remote network.
RIP measures distance by an integer count of the number of hops from one network to another. A router is one hop from a directly connected network, two hops from a network that can be reached through a router, etc. The more routers between a source and a destination, the greater the RIP distance (or hop count).
There are a few rules to the routing table update process that help to improve performance and stability. A router will not replace a route with a newly learned one if the new route has the same hop count (sometimes referred to as ‘cost’). So learned routes are retained until a new route with a lower hop count is learned.
When learned routes are entered into the routing table, a timer is started. This timer is restarted every time this route is advertised. If the route is not advertised for a period of time (usually 180 seconds), the route is removed from the routing table.
RIP does not have an explicit method to detect routing loops. Many RIP implementations include an authorization mechanism (a password) to prevent a router from learning erroneous routes from unauthorized routers.
To maximize stability, the hop count RIP uses to measure distance must have a low maximum value.
Infinity (that is, the network is unreachable) is defined as 16 hops. In other words, if a network is more than 16 routers from the source, the local router will consider the network unreachable.
RIP can also be slow to converge (to remove inconsistent, unreachable or looped routes from the routing table) because RIP messages propagate relatively slowly through a network.
Slow convergence can be solved by using split horizon update, where a router does not propagate information about a route back to the interface on which it was received. This reduces the probability of forming transient routing loops.
Hold down can be used to force a router to ignore new route updates for a period of time (usually 60 seconds) after a new route update has been received. This allows all routers on the network to receive the message.
A router can ‘poison reverse’ a route by adding an infinite (16) hop count to a route’s advertisement.
This is usually used in conjunction with triggered updates, which force a router to send an immediate broadcast when an update of an unreachable network is received.
RIP Version 1 Message Format
There are two types of RIP messages: routing information messages and information requests. The same format is used by both types.
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Figure 5-20. RIP v.1 Message Format
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The COMMAND field specifies an operation according the following table:
Command Meaning
1
2
3
4
5
9
10
11
Request for partial or full routing information
Response containing network-distance pairs from sender’s routing table
Turn on trace mode (obsolete)
Turn off trace mode (obsolete)
Reserved for Sun Microsystem’s internal use
Update Request
Update Response
Update Acknowledgement
Table 5-12. RIP Command Codes
The field VERSION contains the protocol version number (1 in this case), and is used by the receiver to verify which version of RIP the packet was sent from.
RIP 1 Message
RIP is not limited to TCP/IP. Its address format can support up to 14 octets (when using IP, the remaining 10 octets must be zeros). Other network protocol suites can be specified in the Family of
Source Network field (IP has a value of 2). This will determine how the address field is interpreted.
RIP specifies that the IP address 0.0.0.0 denotes a default route.
The distances, measured in router hops are entered in the Distance to Source Network, and Distance to
Destination Network fields.
RIP 1 Route Interpretation
RIP was designed to be used with classed address schemes, and does not include an explicit subnet mask. An extension to version 1 does allow routers to exchange subnetted addresses, but only if the subnet mask used by the network is the same as the subnet mask used by the address. This means the
RIP version 1 cannot be used to propagate classless addresses.
Routers running RIP version 1 must send different update messages for each IP interface to which it is connected. Interfaces that use the same subnet mask as the router’s network can contain subnetted routes, other interfaces cannot. The router will then advertise only a single route to the network.
RIP Version 2 Extensions
RIP version 2 includes an explicit subnet mask entry, so RIP version 2 can be used to propagate variable length subnet addresses or CIDR classless addresses. RIP version 2 also adds an explicit next hop entry, which speeds convergence and helps prevent the formation of routing loops.
RIP2 Message Format
The message format used with RIP2 is an extension of the RIP1 format:
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Figure 5-21. RIP Message Format
RIP version 2 also adds a 16-bit route tag that is retained and sent with router updates. It can be used to identify the origin of the route.
Because the version number in RIP2 occupies the same octet as in RIP1, both versions of the protocols can be used on a given router simultaneously without interference.
Open Shortest Path First (OSPF)
The Open Shortest Path First (OSPF) routing protocol uses a link-state algorithm to determine routes to network destinations. A “link” is an interface on a router and the “state” is a description of that interface and its relationship to neighboring routers. The state contains information such as the IP address, subnet mask, type of network the interface is attached to, other routers attached to the network, etc. The collection of link-states is then collected in a link-state database that is maintained by routers running OSPF.
OSPF specifies how routers will communicate to maintain their link-state database and defines several concepts about the topology of networks that use OSPF.
To limit the extent of link-state update traffic between routers, OSPF defines the concept of Area. All routers within an area share the exact same link-state database, and a change to this database on one router triggers an update to the link-state database of all other routers in that area. Routers that have interfaces connected to more than one area are called Border Routers and take the responsibility of distributing routing information between areas.
One area is defined as Area 0 or the Backbone. This area is central to the rest of the network in that all other areas have a connection (through a router) to the backbone. Only routers have connections to the backbone and OSPF is structured such that routing information changes in other areas will be introduced into the backbone, and then propagated to the rest of the network.
When constructing a network to use OSPF, it is generally advisable to begin with the backbone (area 0) and work outward.
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The Link-State Algorithm
An OSPF router uses a link-state algorithm to build a shortest path tree to all destinations known to the router. The following is a simplified description of the algorithm’s steps:
1. When OSPF is started, or when a change in the routing information changes, the router generates a link-state advertisement. This advertisement is a specially formatted packet that contains information about all the link-states on the router.
2. This link-state advertisement is flooded to all router in the area. Each router that receives the link-state advertisement will store the advertisement and then forward a copy to other routers.
3. When the link-state database of each router is updated, the individual routers will calculate a Shortest Path Tree to all destinations − with the individual router as the root.
The IP routing table will then be made up of the destination address, associated cost, and the address of the next hop to reach each destination.
4. Once the link-state databases are updated, Shortest Path Trees calculated, and the IP routing tables written − if there are no subsequent changes in the OSPF network (such as a network link going down) there is very little OSPF traffic.
The Shortest Path Algorithm
The Shortest Path to a destination is calculated using the Dijkstra algorithm. Each router is places at the root of a tree and then calculates the shortest path to each destination based on the cumulative cost to reach that destination over multiple possible routes. Each router will then have its own
Shortest Path Tree (from the perspective of its location in the network area) even though every router in the area will have and use the exact same link-state database.
The following sections describe the information used to build the Shortest Path Tree.
OSPF Cost
Each OSPF interface has an associated cost (also called “metric”) that is representative of the overhead required to send packets over that interface. This cost is inversely proportional to the bandwidth of the interface (i.e. a higher bandwidth interface has a lower cost). There is then a higher cost (and longer time delays) in sending packets over a 56 Kbps dial-up connection than over a 10 Mbps Ethernet connection. The formula used to calculate the OSPF cost is as follows:
Cost = 100,000,000 / bandwidth in bps
As an example, the cost of a 10 Mbps Ethernet line will be 10 and the cost to cross a 1.544 Mbps T1 line will be 64.
Shortest Path Tree
To build Router A’s shortest path tree for the network diagramed below, Router A is put at the root of the tree and the smallest cost link to each destination network is calculated.
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128.213.0.0
Router B
Router A
192.128.11.0
Router C
Router D
222.211.10.0
Figure 5-22. Constructing a Shortest Path Tree
128.213.0.0
192.213.11.0
5
Router A
0
Router B
10 10
Router C
5
10
Router D
10
222.211.10.0
Figure 5-23. Constructing a Shortest Path Tree
The diagram above shows the network from the viewpoint of Router A. Router A can reach
192.213.11.0 through Router B with a cost of 10+5=15. Router A can reach 222.211.10.0 through
Router C with a cost of 10+10=20. Router A can also reach 222.211.10.0 through Router B and Router
D with a cost of 10+5+10=25, but the cost is higher than the route through Router C. This higher-cost route will not be included in the Router A’s shortest path tree. The resulting tree will look like this:
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128.213.0.0
Router A
0
Router B
10 10
Router C
5 10
192.213.11.0
222.211.10.0
Figure 5-24. Constructing a Shortest Path Tree - Completed
Note that this shortest path tree is only from the viewpoint of Router A. The cost of the link from Router
B to Router A, for instance is not important to constructing Router A’s shortest path tree, but is very important when Router B is constructing its shortest path tree.
Note also that directly connected networks are reached at a cost of 0, while other networks are reached at the cost calculated in the shortest path tree.
Router A can now build its routing table using the network addresses and costs calculated in building the above shortest path tree.
Areas and Border Routers
OSPF link-state updates are forwarded to other routers by flooding to all routers on the network. OSPF uses the concept of areas to define where on the network routers that need to receive particular linkstate updates are located. This helps ensure that routing updates are not flooded throughout the entire network and to reduce the amount of bandwidth consumed by updating the various router’s routing tables.
Areas establish boundaries beyond which link-state updates do not need to be flooded. So the exchange of link-state updates and the calculation of the shortest path tree are limited to the area that the router is connected to.
Routers that have connections to more than one area are called Border Routers (BR). The Border
Routers have the responsibility of distributing necessary routing information and changes between areas.
Areas are specific to the router interface. A router that has all of its interfaces in the same area is called an Internal Router. A router that has interfaces in multiple areas is called a Border Router. Routers that act as gateways to other networks (possibly using other routing protocols) are called Autonomous
System Border Routers (ASBRs).
Link-State Packets
There are different types of link-state packets, four are illustrated below:
• Router Link-State Updates − these describe a router’s links to destinations within an area.
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• Summary Link-State Updates – issued by Border Routers and describe links to networks outside the area but within the Autonomous System (AS).
• Network Link-State Updates – issued by multi-access areas that have more than one attached router. One router is elected as the Designated Router (DR) and this router issues the network link-state updates describing every router on the segment.
• External Link-State Updates – issued by an Autonomous System Border Router and describes routes to destinations outside the AS or a default route to the outside AS.
The format of these link-state updates is described in more detail below.
Router link-state updates are flooded to all routers in the current area. These updates describe the destinations reachable through all of the router’s interfaces.
Summary link-state updates are generated by Border Routers to distribute routing information about other networks within the AS. Normally, all Summary link-state updates are forwarded to the backbone
(area 0) and are then forwarded to all other areas in the network. Border Routers also have the responsibility of distributing routing information from the Autonomous System Border Router in order for routers in the network to get and maintain routes to other Autonomous Systems.
Network link-state updates are generated by a router elected as the Designated Router on a multiaccess segment (with more than one attached router). These updates describe all of the routers on the segment and their network connections.
External link-state updates carry routing information to networks outside the Autonomous System. The
Autonomous System Border Router is responsible for generating and distributing these updates.
OSPF Authentication
OSPF packets can be authenticated as coming from trusted routers by the use of predefined passwords.
The default for routers is to use not authentication.
There are two other authentication methods − simple password authentication (key) and Message
Digest authentication (MD-5).
Simple Password Authentication
A password (or key) can be configured on a per-area basis. Routers in the same area that participate in the routing domain must be configured with the same key. This method is possibly vulnerable to passive attacks where a link analyzer is used to obtain the password.
Message Digest Authentication (MD-5)
MD-5 authentication is a cryptographic method. A key and a key-ID are configured on each router. The router then uses an algorithm to generate a mathematical “message digest” that is derived from the
OSPF packet, the key and the key-ID. This message digest (a number) is then appended to the packet.
The key is not exchanged over the wire and a non-decreasing sequence number is included to prevent replay attacks.
The Backbone and Area 0
OSPF limits the number of link-state updates required between routers by defining areas within which a given router operates. When more than one area is configured, one area is designated as area 0 − also called the backbone.
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The backbone is at the center of all other areas − all areas of the network have a physical (or virtual) connection to the backbone through a router. OSPF allows routing information to be distributed by forwarding it into area 0, from which the information can be forwarded to all other areas (and all other routers) on the network.
In situations where an area is required, but is not possible to provide a physical connection to the backbone, a virtual link can be configured.
Virtual Links
Virtual links accomplish two purposes:
1. Linking an area that does not have a physical connection to the backbone.
2. Patching the backbone in case there is a discontinuity in area 0.
Areas Not Physically Connected to Area 0
All areas of an OSPF network should have a physical connection to the backbone, but is some cases it is not possible to physically connect a remote area to the backbone. In these cases, a virtual link is configured to connect the remote area to the backbone. A virtual path is a logical path between two border routers that have a common area, with one border router connected to the backbone.
Partitioning the Backbone
OSPF also allows virtual links to be configured to connect the parts of the backbone that are discontinuous. This is the equivalent to linking different area 0s together using a logical path between each area 0. Virtual links can also be added for redundancy to protect against a router failure. A virtual link is configured between two border routers that both have a connection to their respective area 0s.
Neighbors
Routers that are connected to the same area or segment become neighbors in that area. Neighbors are elected via the Hello protocol. IP multicast is used to send out Hello packets to other routers on the segment. Routers become neighbors when they see themselves listed in a Hello packet sent by another router on the same segment. In this way, two-way communication is guaranteed to be possible between any two neighbor routers.
Any two routers must meet the following conditions before the become neighbors:
• Area ID − two routers having a common segment − their interfaces have to belong to the same area on that segment. Of course, the interfaces should belong to the same subnet and have the same subnet mask.
• Authentication − OSPF allows for the configuration of a password for a specific area.
Two routers on the same segment and belonging to the same area must also have the same OSPF password before they can become neighbors.
• Hello and Dead Intervals − The Hello interval specifies the length of time, in seconds, between the hello packets that a router sends on an OSPF interface. The dead interval is the number of seconds that a router’s Hello packets have not been seen before its neighbors declare the OSPF router down. OSPF routers exchange Hello packets on each segment in order to acknowledge each other’s existence on a segment and to elect a
Designated Router on multi-access segments. OSPF requires these intervals to be exactly the same between any two neighbors. If any of these intervals are different, these routers will not become neighbors on a particular segment.
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• Stub Area Flag − any two routers also have to have the same stub area flag in their Hello packets in order to become neighbors.
Adjacencies
Adjacent routers go beyond the simple Hello exchange and participate in the link-state database exchange process. OSPF elects one router as the Designated Router (DR) and a second router as the
Backup Designated Router (BDR) on each multi-access segment (the BDR is a backup in case of a DR failure). All other routers on the segment will then contact the DR for link-state database updates and exchanges. This limits the bandwidth required for link-state database updates.
Designated Router Election
The election of the DR and BDR is accomplished using the Hello protocol. The router with the highest
OSPF priority on a given multi-access segment will be elected the DR for that segment. In case of a tie, the router with the highest Router ID wins. The default OSPF priority is 1. A priority of zero indicates a router that cannot be elected as the DR.
Building Adjacency
Two routers undergo a multi-step process in building the adjacency relationship. The following is a simplified description of the steps required:
• Down − No information has been received from any router on the segment.
• Attempt − On non-broadcast multi-access networks (such as Frame Relay or X.25), this state indicates that no recent information has been received from the neighbor. An effort should be made to contact the neighbor by sending Hello packets at the reduced rate set by the Poll Interval.
• Init − The interface has detected a Hello packet coming from a neighbor but bidirectional communication has not yet been established.
• Two-way − Bi-directional communication with a neighbor has been established. The router has seen its address in the Hello packets coming from a neighbor. At the end of this stage the DR and BDR election would have been done. At the end of the Two-way stage, routers will decide whether to proceed in building an adjacency or not. The decision is based on whether one of the routers is a DR or a BDR or the link is a pointto-point or virtual link.
• Exstart − (Exchange Start) Routers establish the initial sequence number that is going to be used in the information exchange packets. The sequence number insures that routers always get the most recent information. One router will become the primary and the other will become secondary. The primary router will poll the secondary for information.
• Exchange − Routers will describe their entire link-state database by sending database description packets.
• Loading − The routers are finalizing the information exchange. Routers have link-state request list and a link-state retransmission list. Any information that looks incomplete or outdated will be put on the request list. Any update that is sent will be put on the retransmission list until it gets acknowledged.
• Full − The adjacency is now complete. The neighboring routers are fully adjacent.
Adjacent routers will have the same link-state database.
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Adjacencies on Point-to-Point Interfaces
OSPF Routers that are linked using point-to-point interfaces (such as serial links) will always form adjacencies. The concepts of DR and BDR are unnecessary.
OSPF Packet Formats
All OSPF packet types begin with a standard 24-byte header and there are five packet types. The header is described first, and each packet type is described in a subsequent section.
All OSPF packets (except for Hello packets) forward link-state advertisements. Link-State Update packets, for example, flood advertisements throughout the OSPF routing domain.
• OSPF packet header
• Hello packet
• Database Description packet
• Link-State Request packet
• The Link-State Update packet
• Link-State Acknowledgment packet
The OSPF Packet Header
Every OSPF packet is preceded by a common 24-byte header. This header contains the information necessary for a receiving router to determine if the packet should be accepted for further processing.
The format of the OSPP packet header is shown below:
OSPF Packet Header
Version No.
Type Packet Length
Router ID
Area ID
Checksum Authentication Type
Authentication
Authentication
Figure 5-25. OSPF Packet Header
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Field
Version No.
Type
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Description
The OSPF version number
The OSPF packet type. The OSPF packet types are as follows:
Type Description
1 Hello
Packet Length
Router ID
Area ID
Checksum
Authentication Type
Authentication
The length of the packet in bytes. This length includes the 24-byte header.
The Router ID of the packet’s source.
A 32-bit number identifying the area that this packet belongs to. All OSPF packets are associated with a single area. Packets traversing a virtual link are assigned the backbone Area ID of
0.0.0.0
A standard IP checksum that includes all of the packet’s contents except for the 64-bit authentication field.
The type of authentication to be used for the packet.
A 64-bit field used by the authentication scheme.
Table 5-13. OSPF Packet Header
The Hello Packet
Hello packets are OSPF packet type 1. They are sent periodically on all interfaces, including virtual links, in order to establish and maintain neighbor relationships. In addition, Hello Packets are multicast on those physical networks having a multicast or broadcast capability, enabling dynamic discovery of neighboring routers.
All routers connected to a common network must agree on certain parameters such as the Network
Mask, the Hello Interval, and the Router Dead Interval. These parameters are included in hello packets, so that differences can inhibit the forming of neighbor relationships. A detailed explanation of the receive processing for Hello packets, so that differences can inhibit the forming of neighbor relationships.
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The format of the Hello packet is shown below:
Hello Packet
Version No.
1 Packet Length
Router ID
Area ID
Checksum Authentication Type
Authentication
Authentication
Network Mask
Hello Interval Options
Router Dead Interval
Designated Router
Backup Designated Router
Neighbor
Router Priority
Figure 5-26. Hello Packet
Field Description
Network Mask
Options
Hello Interval
Router Priority
Router Dead Interval
The network mask associated with this interface.
The optional capabilities supported by the router.
The number of seconds between this router’s Hello packets.
This router’s Router Priority. The Router Priority is used in the election of the DR and BDR. If this field is set to 0, the router is ineligible to become the DR or the BDR.
The number of seconds that must pass before declaring a silent router as down.
Designated Router The identity of the DR for this network, in the view of the advertising router. The DR is identified here by its IP interface address on the network.
Backup Designated Router The identity of the Backup Designated Router (BDR) for this network. The BDR is identified here by its IP interface address on the network. This field is set to
0.0.0.0 if there is no BDR.
Neighbor The Router Ids of each router from whom valid Hello packets have been seen within the Router Dead
Interval on the network.
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Table 5-14. Hello Packet
The Database Description Packet
Database Description packets are OSPF packet type 2. These packets are exchanged when an adjacency is being initialized. They describe the contents of the topological database. Multiple packets may be used to describe the database. For this purpose a poll-response procedure is used. One of the routers is designated to be master, the other a slave. The master seconds Database Description packets
(polls) that are acknowledged by Database Description packets sent by the slave (responses). The responses are linked to the polls via the packets’ DD sequence numbers.
Database Description Packet
Version No.
Checksum
2 Packet Length
Router ID
Area ID
Authentication
Authentication
Authentication Type
Reserved I M MS Reserved
DD Sequence No.
Link-State Advertisement Header ...
Options
Figure 5-27. Database Description Packet
Field
Options
I – bit
M – bit
MS – bit
Description
The optional capabilities supported by the router.
The Initial bit. When set to 1, this packet is the first in the sequence of Database Description packets.
The More bit. When set to 1, this indicates that more Database Description packets will follow.
The Master Slave bit. When set to 1, this indicates that the router is the master during the Database
Exchange process. A zero indicates the opposite.
User to sequence the collection of Database
Description Packets. The initial value (indicated by the Initial bit being set) should be unique. The DD sequence number then increments until the complete database description has been sent.
Table 5-15. Database Description Packet
The rest of the packet consists of a list of the topological database’s pieces. Each link state advertisement in the database is described by its link state advertisement header.
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The Link-State Request Packet
Link-State Request packets are OSPF packet type 3. After exchanging Database Description packets with a neighboring router, a router may find that parts of its topological database are out of date. The
Link-State Request packet is used to request the pieces of the neighbor’s database that are more up to date. Multiple Link-State Request packets may need to be used. The sending of Link-State Request packets is the last step in bringing up an adjacency.
A router that sends a Link-State Request packet has in mind the precise instance of the database pieces it is requesting, defined by LS sequence number, LS checksum, and LS age, although these fields are not specified in the Link-State Request packet itself. The router may receive even more recent instances in response.
The format of the Link-State Request packet is shown below:
Link-State Request Packet
Version No.
Checksum
3 Packet Length
Router ID
Area ID
Authentication
Authentication
Link-State Type
Authentication Type
Link-State ID
Advertising Router
Figure 5-29. Link-State Request Packet
Each advertisement requested is specified by its Link-State Type, Link-State ID, and Advertising
Router. This uniquely identifies the advertisement, but not its instance. Link-State Request packets are understood to be requests for the most recent instance.
The Link-State Update Packet
Link-State Update packets are OSPF packet type 4. These packets implement the flooding of link-state advertisements. Each Link-State Update packet carries a collection of link-state advertisements one hop further from its origin. Several link-state advertisements may be included in a single packet.
Link-State Update packets are multicast on those physical networks that support multicast/broadcast.
In order to make the flooding procedure reliable, flooded advertisements are acknowledged in Link-
State Acknowledgment packets. If retransmission of certain advertisements is necessary, the retransmitted advertisements are always carried by unicast Link-State Update packets.
The format of the Link-State Update packet is shown below:
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Link-State Update Packet
Version No.
4
Packet Length
Router ID
Area ID
Checksum Authentication Type
Authentication
Authentication
Number of Advertisements
Link-State Advertisements ...
Figure 5-30. Link-State Update Packet
The body of the Link-State Update packet consists of a list of link-state advertisements. Each advertisement begins with a common 20-byte header, the link-state advertisement header. Otherwise, the format of each of the five types of link-state advertisements is different.
The Link-State Acknowledgment Packet
Link-State Acknowledgment packets are OSPF packet type 5. To make the folding of link-state advertisements reliable, flooded advertisements are explicitly acknowledged. This acknowledgment is accomplished through the sending and receiving of Link-State Acknowledgment packets. Multiple linkstate advertisements can be acknowledged in a single Link-State Acknowledgment packet.
Depending on the state of the sending interface and the source of the advertisements being acknowledged, a Link-State Acknowledgment packet is sent either to the multicast address
AllSPFRouters, to the multicast address AllDRouters, or as a unicast packet.
The format of this packet is similar to that of the Data Description packet. The body of both packets is simply a list of link-state advertisement headers.
The format of the Link-State Acknowledgment packet is shown below:
Link-State Acknowledgment Packet
Version No.
5 Packet Length
Router ID
Area ID
Checksum Authentication Type
Authentication
Authentication
Link-State Advertisement Header ...
Figure 5-31. Link-State Acknowledgement Packet
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Each acknowledged link-state advertisement is described by its link-state advertisement header. It contains all the information required to uniquely identify both the advertisement and the advertisement’s current instance.
Link-State Advertisement Formats
There are five distinct types of link-state advertisements. Each link-state advertisement begins with a standard 20-byte link-state advertisement header. Succeeding sections then diagram the separate linkstate advertisement types.
Each link-state advertisement describes a piece of the OSPF routing domain. Every router originates a router links advertisement. In addition, whenever the router is elected as the Designated Router, it originates a network links advertisement. Other types of link-state advertisements may also be originated. The flooding algorithm is reliable, ensuring that all routers have the same collection of linkstate advertisements. The collection of advertisements is called the link-state (or topological) database.
From the link-state database, each router constructs a shortest path tree with itself as root. This yields a routing table.
There are four types of link state advertisements, each using a common link state header. These are:
• Router Links Advertisements
• Network Links Advertisements
• Summary Link Advertisements
• Autonomous System Link Advertisements
The Link State Advertisement Header
All link state advertisements begin with a common 20-byte header. This header contains enough information to uniquely identify the advertisements (Link State Type, Link State ID, and Advertising
Router). Multiple instances of the link state advertisement may exist in the routing domain at the same time. It is then necessary to determine which instance is more recent. This is accomplished by examining the link state age, link state sequence number and link state checksum fields that are also contained in the link state advertisement header.
The format of the Link State Advertisement Header is shown below:
Link-State Advertisement Header
Link-State Age Options
Link-State ID
Advertising Router
Link-State Sequence Number
Link-State Checksum
Length
Link-State Type
Figure 5-32. Link-State Advertisement Header
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Field
Link State Age
Options
Link State Type
Description
The time is seconds since the link state advertisement was originated.
The optional capabilities supported by the described portion of the routing domain.
The type of the link state advertisement. Each link state type has a separate advertisement format. The link state type are as follows:
Type Description
1 Router Links
Link State ID
3
4
Summary Link (IP Network)
Summary Link (ASBR)
5 AS External Link
This field identifies the portion of the internet environment that is being described by the advertisement. The contents of this field depend on the advertisement’s Link State Type.
Advertising Router
Link State Sequence
Number
Detects old or duplicate link state advertisements. Successive instances of a link state advertisement are given successive Link
State Sequence numbers.
Link State Checksum
The Router ID of the router that originated the Link State
Advertisement. For example, in network links advertisements this field is set to the Router ID of the network’s Designated
Router.
Length
The Fletcher checksum of the complete contents of the link state advertisement, including the link state advertisement header except for the Link State Age field.
The length in bytes of the link state advertisement. This includes the 20-byte link state advertisement header.
Table 5-16. Link-State Advertisement Header
Router Links Advertisements
Router links advertisements are type 1 link state advertisements. Each router in an area originates a routers links advertisement. The advertisement describes the state and cost of the router’s links to the area. All of the router’s links to the area must be described in a single router links advertisement.
The format of the Router Links Advertisement is shown below:
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Routers Links Advertisements
Link-State Age Options Link-State Type
Link-State ID
Advertising Router
Link-State Sequence Number
Link-State Checksum
Length
Reserved V E B Reserved Number of Links
Link ID
Type
TOS
Link Data
No. Of TOS
0
...
TOS 0 Metric
Metric
TOS 0 Metric
...
Link ID
Link Data
Figure 5-33. Routers Links Advertisement
In router links advertisements, the Link State ID field is set to the router’s OSPF Router ID. The T – bit is set in the advertisement’s Option field if and only if the router is able to calculate a separate set of routes for each IP Type of Service (TOS). Router links advertisements are flooded throughout a single area only.
Field
V – bit
E – bit
B – bit
Number of Links
Description
When set, the router is an endpoint of an active virtual link that is using the described area as a
Transit area (V is for Virtual link endpoint).
When set, the router is an Autonomous System
(AS) boundary router (E is for External).
When set, the router is an area border router (B is for Border).
The number of router links described by this advertisement. This must be the total collection of router links to the area.
Table 5-17. Routers Links Advertisement
The following fields are used to describe each router link. Each router link is typed. The Type field indicates the kind of link being described. It may be a link to a transit network, to another router or to a stub network. The values of all the other fields describing a router link depend on the link’s Type. For example, each link has an associated 32-bit data field. For links to stub networks this field specifies the
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Field
Type
Description
A quick classification of the router link. One of the following:
Type Description
2
3
Connection to a transit network.
Connection to a stub network.
Link Data
Link ID
No. of TOS
TOS 0 Metric
Identifies the object that this router link connects to. Value depends on the link’s Type. When connecting to an object that also originates a link state advertisement (i.e. another router or a transit network) the Link ID is equal to the neighboring advertisement’s Link State ID. This provides the key for looking up an advertisement in the link state database.
Type Link ID
1 Neighboring router’s Router ID.
2
3
IP address of Designated Router.
IP network/subnet number.
4 Neighboring router’s Router ID
Contents again depend on the link’s Type field. For connections to stub networks, it specifies the network’s IP address mask.
For unnumbered point-to-point connection, it specifies the interface’s MIB-II ifIndex value. For other link types it specifies the router’s associated IP interface address. This latter piece of information is needed during the routing table build process, when calculating the IP address of the next hop.
The number of different Type of Service (TOS) metrics given for this link, not counting the required metric for TOS 0. If no additional TOS metrics are given, this field should be set to 0.
The cost of using this router link for TOS 0.
Table 5-18. Routers Links Advertisements − Continued
For each link, separate metrics may be specified for each Type of Service (TOS). The metric for TOS 0 must always be included, and was discussed above. Metrics for non-zero TOS are described below. Note that the cost for non-zero TOS values that are not specified defaults to the TOS 0 cost. Metrics must be listed in order of increasing TOS encoding. For example, the metric for TOS 16 must always follow the metric for TOS 8 when both are specified.
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Field
TOS
Metric
Description
IP Type of Service that this metric refers to.
The cost of using this outbound router link, for traffic of the specified TOS.
Table 5-19. Routers Links Advertisement − Continued
Network Links Advertisements
Network links advertisements are Type 2 link state advertisements. A network links advertisement is originated for each transit network in the area. A transit network is a multi-access network that has more than one attached router. The network links advertisement is originated by the network’s
Designated router. The advertisement describes all routers attached to the network, including the
Designated Router itself. The advertisement’s Link State ID field lists the IP interface address of the
Designated Router.
The distance form the network to all attached routers is zero, for all TOS. This is why the TOS and metric fields need not be specified in the network links advertisement.
The format of the Network Links Advertisement is shown below:
Network Link Advertisements
Link-State Age Options
Link-State ID
Advertising Router
Link-State Sequence Number
Link-State Checksum
Length
Network Mask
Attached Router
2
Figure 5-34. Network Link Advertisement
Field
Network Mask
Attached Router
Description
The IP address mask for the network.
The Router Ids of each of the routers attached to the network. Only those routers that are fully adjacent to the Designated Router (DR) are listed. The DR includes itself in this list.
Table 5-20. Network Link Advertisement
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Summary Link Advertisements
Summary link advertisements are Type 3 and 4 link state advertisements. These advertisements are originated by Area Border routers. A separate summary link advertisement is made for each destination known to the router, that belongs to the Autonomous System (AS), yet is outside the area.
Type 3 link state advertisements are used when the destination is an IP network. In this case the advertisement’s Link State ID field is an IP network number. When the destination is an AS boundary router, a Type 4 advertisement is used, and the Link State ID field is the AS boundary router’s OSPF
Router ID. Other that the difference in the Link State ID field, the format of Type 3 and 4 link state advertisements is identical.
Summary Link Advertisements
TOS
Link-State Age
Link-State ID
Options
Advertising Router
Link-State Sequence Number
Link-State Checksum
Length
Network Mask
Metric
2
Figure 5-35. Summary Link Advertisement
For stub area, Type 3 summary link advertisements can also be used to describe a default route on a per-area basis. Default summary routes are used in stub area instead of flooding a complete set of external routes. When describing a default summary route, the advertisement’s Link State ID is always set to the Default Destination − 0.0.0.0, and the Network Mask is set to 0.0.0.0.
Separate costs may be advertised for each IP Type of Service. Note that the cost for TOS 0 must be included, and is always listed first. If the T-bit is reset in the advertisement’s Option field, only a route for TOS 0 is described by the advertisement. Otherwise, routes for the other TOS values are also described. If a cost for a certain TOS is not included, its cost defaults to that specified for TOS 0.
Field
TOS
Metric
Description
For Type 3 link state advertisements, this indicates the destination network’s IP address mask. For example, when advertising the location of a class A network the value
0xff000000
The Type of Service that the following cost is relevant to.
The cost of this route.
Expressed in the same units as the interface costs in the router links advertisements.
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Table 5-21. Summary Link Advertisement
Autonomous Systems External Link Advertisements
Autonomous Systems (AS) link advertisements are Type 5 link state advertisements. These advertisements are originated by AS boundary routers. A separate advertisement is made for each destination known to the router that is external to the AS.
AS external link advertisements usually describe a particular external destination. For these advertisements the Link State ID field specifies an IP network number. AS external link advertisements are also used to describe a default route. Default routes are used when no specific route exists to the destination. When describing a default route, the Link Stat ID is always set the Default Destination address (0.0.0.0) and the Network Mask is set to 0.0.0.0.
The format of the AS External Link Advertisement is shown below:
AS External Link Advertisements
E TOS
Link-State Age Options
Link-State ID
Advertising Router
Link-State Sequence Number
Link-State Checksum Length
Network Mask
Metric
Forwarding Address
External Route Tag
5
Figure 5-36. AS External Link Advertisement
Field
Network Mask
E – bit
Forwarding Address
TOS
Metric
Description he IP address mask for the advertised destination.
The type of external metric. If the E – bit is set, the metric specified is a Type 2 external metric. This means the metric is considered larger than any link state path. If the E – bit is zero, the specified metric is a Type 1 external metric. This means that is comparable directly to the link state metric.
Data traffic for the advertised destination will be forwarded to this address. If the Forwarding Address is set to 0.0.0.0, data traffic will be forwarded instead to the advertisement’s originator.
The Type of Service that the following cost is relevant to.
The cost of this route. The interpretation of this metric depends on the external type indication (the E – bit above).
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External Route Tag A 32-bit field attached to each external route. This is not used by the OSPF protocol itself.
Table 5-21. AS External System Advertisement
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6
C
ONFIGURING THE
S
WITCH
U
SING THE
C
ONSOLE
I
NTERFACE
The DES-3326 supports a console management interface that allows the user to connect to the switch’s management agent via a serial port and a terminal or a computer running a terminal emulation program. The console can also be used over the network using the TCP/IP Telnet protocol. The console program can be used to configure the switch to use an SNMP-based network management software over the network.
This chapter describes how to use the console interface to access the switch, change its settings, and monitor its operation.
Switch configuration settings that are saved to non-volatile RAM using Save
Changes from the Main Menu are retained in the switch’s memory, and are reloaded when the switch is rebooted.
Before You Start
The DES-3326 supports a wide array of functions and gives great flexibility and increased network performance by eliminating the routing bottleneck between the WAN and the intranet. Its function in a network can be thought of as a new generation of wire-speed router that performs routing functions in hardware, rather than in software.
General Deployment Strategy
The DES-3326 has many automatic features to detect the network topology and adapt to changes in this topology, but it is recommended that a network scheme be developed and entered statically into the DES-3326.
1. Determine how the network would be best segmented. This is probably done using VLANs in an existing layer 2 switched network.
2. Develop an IP addressing scheme. This involves allocating a block of IP addresses to each network segment. Each network subnet is then assigned a network address and a subnet mask.
3. Determine which network resources must be shared by the subnets. Shared resources may be connected directly to the Layer 3 switch, if need be. Static routes to each of the shared resources should be determined.
4. Determine how each subnet will communicate with the WAN or Internet. Again, static routes should be determined and default gateways identified.
5. Develop a security scheme. Some subnets on the network need more security or should be isolated from the other subnets. IP or MAC filtering can be used. Also, one or more VLANs on the Layer 3 switch can be configured without an IP subnet – in which case, these VLANs will
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DES-3326 Layer 3 Fast Ethernet Switch User’s Guide function as a layer 2 VLAN and would require an external router to connect to the rest of the network.
6. Develop a policy scheme. Some subnets will have a greater need for multicasting bandwidth, for example. A policy is a mechanism to alter the normal packet forwarding in a network device, and can be used to intelligently allocate bandwidth to time-critical applications such as the integration of voice, video, and data on the network.
7. Develop a redundancy scheme. Planning redundant links and routes to critical network resources can save valuable time in the case of a link or device failure. The DES-3326’s
Spanning Tree function can be used to block the redundant link until it is needed.
VLAN Layout
VLANs on the DES-3326 have more functions than on a traditional layer 2 switch, and must therefore be laid-out and configured with a bit more care. Layer 3 VLANs (VLANs that have an IP interface assigned to them) can be thought of as network links – not just as a collection of associated end users.
Further, Layer 3 VLANs are assigned an IP interface address and subnet mask to enable IP routing between them.
IEEE 802.1Q VLANs must be configured on the switch before they can be assigned IP interface addresses or subnet masks. Further, the static VLAN configuration is specified on a per port basis. On the DES-3326, a VLAN can consist of end-nodes – just like a traditional layer 2 switch, but a VLAN can also consist of a subnetwork defined by an IP interface address and a subnet mask.
The IP subnets for the network must be determined first, and the VLANs configured on the switch to accommodate the IP subnets. Finally, the IP subnets can be assigned to the VLANs.
Assigning IP Interface Addresses and Subnet Masks to VLANs
The DES-3326 allows the assignment of IP subnets to individual VLANs. Any VLAN configured on the switch that is not assigned an IP subnet, will behave as a layer 2 VLAN and will not be capable of IP routing – even if the switch is in IP Routing mode.
Developing an IP addressing scheme is a complex subject, but it is sufficient here to mention that the total number of anticipated end nodes – for each Layer 3 VLAN – must be accommodated with a unique
IP address. It should be noted that the switch regards a VLAN with an IP interface address and corresponding subnet mask assigned as an IP subnet in IP Routing mode.
Defining Static Routes
Routes between the IP interfaces and a default gateway or other router with a WAN connection should be determined beforehand and entered into the static/default routing table on the DES-3326.
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Connecting to the Switch
The console interface is used by connecting the Switch to a VT100-compatible terminal or a computer running an ordinary terminal emulator program (e.g., the HyperTerminal program included with the
Windows operating system) using an RS-232C serial cable. Your terminal parameters will need to be set to:
• VT-100/ANSI compatible
• 9,600 baud
• 8 data bits
• No parity
• One stop bit
• No flow control
You can also access the same functions over a Telnet interface. Once you have set an IP address for your Switch, you can use a Telnet program (in VT-100 compatible terminal mode) to access and control the Switch. All of the screens are identical, whether accessed from the console port or from a Telnet interface.
Console Usage Conventions
The console interface makes use of the following conventions:
1. Items in <angle brackets> can be toggled between several choices using the space bar.
2. Items in [square brackets]can be changed by typing in a new value. You can use the backspace and delete keys to erase characters behind and in front of the cursor.
3. The up and down arrow keys, the left and right arrow keys, the tab key and the backspace key, can be used to move between selected items.
4. Items in UPPERCASE are commands. Moving the selection to a command and pressing Enter will execute that command, e.g. APPLY, etc.
The APPLY command makes the configuration active for the current session only. If the switch is rebooted, the unsaved changes will be lost and the last configuration saved to Non-volatile RAM will be loaded into the switch. Use Save Changes from the main menu to enter the current configuration into the switch’s Non-volatile RAM.
First Time Connecting To The Switch
The Switch supports user-based security that can allow you to prevent unauthorized users from accessing the Switch or changing its settings. This section explains how to log onto the Switch.
The passwords used to access the Switch are case-sensitive; therefore, “S” is not the same as “s.”
When you first connect to the Switch, you will be presented with the first login screen
(shown below).
Press Ctrl+R to refresh the screen. This command can be used at any time to force the console program in the switch to refresh the console screen.
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Figure 6-1. Initial Console screen
The factory default Username is “admin”, there is no factory default password. Enter
“admin” for the Username and leave the Password field blank to access the console
initially
Enter the factory default username (“admin”) and leave the Password field blank. Press Enter and
Access will be given to the main menu, as shown below:
Figure 6-2. Main Menu
The first user automatically gets Root privileges (See Table 6-1). It is recommended to create at least one Root-level user for the Switch.
Creating User Accounts
To create a new user account, highlight Setup User Accounts from the Main Menu and press Enter:
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Figure 6-3. Main Menu
Figure 6-4. Setup User Accounts Menu
User Accounts Management
From the Main Menu, highlight Setup User Accounts and press Enter, then the Setup User Accounts menu appears.
1. Toggle the Action field to Add using the space bar. This will allow the addition of a new user. The other options are Delete, this allows the deletion of a user entry, and Update, this allows for changes to be made to an existing user entry.
2. Enter the new user name, assign an initial password, and then confirm the new password.
Determine whether the new user should have Root, User+, or User privileges. The space bar toggles between the three options.
3. Highlight APPLY and press enter to make the user addition effective.
4. Press Esc. to return to the previous screen or Ctrl+T to go to the root screen.
5. APPLY makes changes to the switch configuration for the current session only. All permanent changes must be entered into non-volatile ram using the Save Changes command on the Main Menu.
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Root, User+ and Normal User Privileges
There are three levels of user privileges: Root and User+, and User.
Switch
Configuration
Management
Configuration
Network
Monitoring
Community
Strings and Trap
Stations
Update Firmware and Configuration
Files
System Utilities
Factory Reset
Privilege
Root
Yes
Yes
Yes
Yes No No
Yes
Yes
User+
Read Only
Read Only
Read Only
Ping only
No
User
Read Only
Read Only
Read Only
Ping only
No
Reboot Switch Yes
User Accounts Management
Yes No
Add/Update/Delet e User Accounts
View User
Accounts
Yes No No
Yes No No
Table 6-1. Root, User+, and User Privileges
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Saving Changes
Selecting APPLY from a console menu makes the configuration effective for the current session only. The configuration data will be lost if the switch is restarted.
To make the configuration effective after a switch restart, select Save Changes to enter the configuration into non-volatile (NV-RAM).
The DES-3326 has two levels of memory: normal RAM and non-volatile or NV-RAM. Configuration changes are made effective by highlighting APPLY and pressing Enter. When this is done, the settings will be immediately applied to the switching software in RAM, and will immediately take effect.
Some settings, though, require you to restart the switch before they will take effect. Restarting the switch erases all settings in RAM and reloads the stored settings from the NV-RAM. Thus, it is necessary to save all setting changes to NV-RAM before rebooting the switch.
Figure 6-5. Main Menu
To retain any configuration changes permanently, highlight Save Changes from the Main Menu. The following screen will appear to verify that your new settings have been saved to NV-RAM:
Figure 6-6. Save Changes Confirmation screen
Once the switch configuration settings have been saved to NV-RAM, they become the default settings for the switch. These settings will be used every time the switch is rebooted.
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Loading Factory Defaults
Loading the factory defaults returns the switch’s configuration to the factory default values. This will clear all settings and restore them to their initial values listed in the appendix.
Figure 6-7. Main Menu
Highlight Reboot from the Main Menu and press Enter.
Figure 6-8. System Reboot menu
To execute a factory reset, highlight either Reboot & Load Factory Default Configuration or Reboot &
Load Factory Default Configuration Except IP Address and press enter. A confirmation screen will appear.
Highlight Yes and press Enter to reset the switch’s NV-RAM to the factory default settings. This will erase any User Accounts (and all other configuration settings) you may have entered and return the switch to the state it was in when it was purchased.
Logging Onto The Switch Console
To log in once you have created a registered user, from the Login screen:
1. Type in your Username and press Enter.
2. Type in your Password and press Enter.
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3. The Main Menu screen will be displayed based on your access level or privilege.
Updating or Deleting User Accounts
To update or delete a user password:
Choose Setup User Accounts from the Main Menu. The following Setup User Accounts menu appears:
Figure 6-9. Setup User Accounts screen
1. Toggle the Action field using the space bar to choose Add, Update, or Delete.
2. Type in the Username for the user account you wish to change and enter the Old Password for that user account.
3. You can now modify the password or the privilege level for this user account.
4. If the password is to be changed, type in the New Password you have chosen, and press
Enter. Type in the same new password in the following field to verify that you have not mistyped it.
5. If the privilege level is to be changed, toggle the Access Level field until the appropriate level is displayed – Root, User+ or User.
6. Highlight APPLY and press Enter to make the change effective.
7. You must enter the configuration changes into the non-volatile ram (NV-RAM) using Save
Changes from the Main Menu if you want the configuration to be used after a switch reboot.
Only a user with Root privileges can make changes to user accounts.
Viewing Current User Accounts
Access to the console, whether using the console port or via Telnet, is controlled using a user name and password. Up to eight user accounts can be created. The console interface will not let you delete the current logged-in user, to prevent accidentally deleting all of the users with Root privilege.
Only users with the Root privilege can delete users.
To view the current user accounts:
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Highlight Setup User Accounts from the Main Menu. The current user accounts can be read from following screen:
Deleting a User Account
To delete a user account:
Figure 6-10. Setup User Accounts screen
Figure 6-11. Setup User Accounts screen
1. Toggle the Action field to Delete.
2. Enter the Username and Old Password for the account you want to delete. You must enter the password for the account to be able to delete it.
3. Highlight APPLY and press Enter to make the deletion of the selected user take effect.
4. You must enter the configuration changes into the non-volatile ram (NV-RAM) using Save
Changes from the Main Menu if you want the configuration to be used after a switch reboot.
Only users with Root privileges can delete user accounts.
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Setting Up The Switch
Basic Setup
This section will help prepare the Switch user by describing the Switch Information, IP Setup,
Remote Management Setup, Configure Ports, Serial Port Settings and Switch Settings menus.
Figure 6-12. Main Menu – Switch Information
Switch Information
Highlight Switch Information from the Main Menu and press Enter:
Figure 6-13. Switch Information screen
The Switch Information shows the operation mode of switch (Layer 3 or Layer 2), which (if any) external modules are installed, and the switch’s MAC Address (assigned by the factory and unchangeable). In addition, the Boot PROM and Firmware Version numbers are shown. This information is helpful to keep track of PROM and Firmware updates and to obtain the switch’s MAC address for entry into another network device’s address table – if necessary.
You can also enter the name of the System, its location, and the name and telephone number of the
System Administrator. It is recommended that the person responsible for the maintenance of the network system that this Layer 3 switch is installed on be listed here.
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Remote Management Setup
Configuring the Switch’s IP Address
The BOOTP and DHCP Server options for assigning the switch an IP address and subnet mask are only available when the switch is in Layer 2 Only mode. The IP
Routing mode requires a manual entry of the IP address and subnet mask.
The Switch needs to have an IP address assigned to it so that an In-Band network management system
(for example, the DView or Telnet) client can find it on the network. The IP Setup screen allows you to change the settings for the Ethernet interface used for in-band communication.
The fields listed under the Current Switch IP Settings heading are those that are currently being used by the switch. Those fields listed under the Restart Settings heading are those which will be used after the APPLY button is selected.
To set the switch’s IP address:
Highlight Remote Management Setup from the Main Menu and press Enter.
Figure 6-14. Remote Management Setup menu
The switch’s factory default IP address is 10.90.90.90 with a subnet mask of 255.0.0.0
and a default gateway of 0.0.0.0. address:
To manually assign the switch’s IP address, subnet mask, and default gateway
Highlight the IP Address field and enter the appropriate IP address.
Highlight the Subnet Mask field and enter the appropriate subnet mask.
If you want to access the switch from a different subnet from the one it is installed on, highlight the
Default Gateway field and enter the IP address of the gateway. If you will manage the switch from the subnet on which it is installed, you can leave the default address in this field.
To use the BOOTP/DHCP protocols to assign the switch an IP address, subnet mask, and default gateway address:
Toggle the Get IP From field using the space bar to choose from Manual, BOOTP, or DHCP. This selects how the switch will be assigned an IP address on the next reboot (or startup).
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The Get IP From options are:
• BOOTP – The switch will send out a BOOTP broadcast request when it is powered up. The
BOOTP protocol allows IP addresses, network masks, and default gateways to be assigned by a central BOOTP server. If this option is set, the Switch will first look for a BOOTP server to provide it with this information before using the default or previously entered settings.
• DHCP – The switch will send out a DHCP broadcast request when it is powered up. The
DHCP protocol allows IP addresses, network masks, and default gateways to be assigned by a
DHCP server. If this option is set, the switch will first look for a DHCP server to provide it with this information before using the default or previously entered settings.
• Manual – Allows the entry of an IP address, Subnet Mask, and a Default Gateway for the switch. These fields should be of the form xxx.xxx.xxx.xxx, where each xxx is a number
(represented in decimal form) between 0 and 255. This address should be a unique address on the network assigned for use by the Network Administrator. The fields which require entries under this option are as follows:
• Subnet Mask – A Bitmask that determines the extent of the subnet that the Switch is on.
Should be of the form xxx.xxx.xxx.xxx, where each xxx is a number (represented in decimal) between 0 and 255. The value should be 255.0.0.0 for a Class A network, 255.255.0.0 for a
Class B network, and 255.255.255.0 for a Class C network, but custom subnet masks are allowed.
• Default Gateway – IP address that determines where packets with a destination address outside the current subnet should be sent. This is usually the address of a router or a host acting as an IP gateway. If your network is not part of an intranet, or you do not want the
Switch to be accessible outside your local network, you can leave this field unchanged.
• Management VID – This field allows the entry of a VLAN ID (VID) from which a management station (a computer) will be allowed to manage the switch using TCP/IP (in-band, or over the network). Management stations that are on VLANs other than the one entered in the
Management VID field will not be able to manage the switch in-band unless their IP addresses are entered in the Management Station IP Addresses field. Any VID that has been configured on the switch can be entered in this field.
SNMP Settings
Some settings must be entered to allow the switch to be managed from an SNMP-based Network
Management System such as SNMP v1 or to be able to access the Switch using the Telnet protocol or the Web-based Manager. Please see the next chapter for Web-based network management information.
To setup the switch for remote management:
Highlight Remote Management Setup from the Main Menu. The following screen appears:
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Figure 6-15. Remote Management Setup menu
Management stations are computers on the network that will be used to manage the switch. You can limit the number of possible management stations by entering up to three IP addresses in the
Management Station IP Settings field. If the three IP Address fields contain all zeros (“0”), then any station with any IP address can access the switch to manage and configure it. If there is one or more IP addresses entered in the IP Address field, then only stations with the IP addresses entered will be allowed to access the switch to manage or configure it.
Setting Up Trap Receivers
This allows the switch to send traps (messages about errors, etc.) to management stations on the network. Highlight Setup Trap Receivers and press Enter. The trap recipients can be setup from the following screen:
Figure 6-16. Setup Trap Recipients menu
The IP Address field is the IP address of a management station (a computer) that is configured to receive the SNMP traps from the switch.
The SNMP Community String is similar to a password in that stations that do not know the correct string cannot receive or request SNMP information from the switch.
The Status field can be toggled between Enabled and Disabled to enable or disable the receipt of SNMP traps by the listed management stations.
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Configure Ports
Highlight Configure Ports from the Main Menu and press Enter:
Figure 6-17. Configure Ports Screen
Toggle the View Ports field, using the space bar, to view the configuration of either ports 1 through 12 or ports 13 through 24. To configure a specific port, toggle the Configure Port field until the appropriate port number appears.
Toggle the State field to either Enabled or Disabled a given port.
Toggle the Speed/Duplex field to either select the speed and duplex/half-duplex state of the port. Auto
– auto-negotiation between 10 and 100 Mbps devices, full- or half-duplex. The Auto setting allows the port to automatically determine the fastest settings the device the port is connected to can handle, and then to use those settings. The other options are 100M/Full, 100M/Half, 10M/Full, and 10M/Half.
There is no automatic adjustment of port settings with any option other than Auto.
Port Locking
A given port’s (or a range of port’s) dynamic MAC address learning can be locked such that the current source MAC addresses entered into the MAC address forwarding table can not be changed once the port lock is enabled. The port can be locked by toggling the Lock field to Enabled, highlighting APPLY and pressing Enter.
This is a security feature that prevents unauthorized computers (with source MAC addresses unknown to the switch prior to locking the port (or ports)) from connecting to the switch’s locked ports and gaining access to the network.
Highlight APPLY and press Enter to make the changes current.
The following fields can be set:
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Parameter Description
View Ports:
<1 to 12 >
Toggle the View Ports field, using the space bar, to view the configuration of either ports 1 through 12 or ports 13 through 24. the given port.
Speed/Duplex:
<Auto>
Toggle the Speed/Duplex field to either select the speed and duplex/half-duplex state of the port.
Auto – auto-negotiation between 10 and 100 Mbps devices, full- or half-duplex. The Auto setting allows the port to automatically determine the fastest settings the device the port is connected to can handle, and then to use those settings. The other options are 100M/Full, 100M/Half, 10M/Full, and
10M/Half. There is no automatic adjustment of port settings with any option other than Auto.
Flow Control:
Auto
Displays the flow control scheme used for the various port configurations. Ports configured for full-duplex use 802.3x flow control, half-duplex ports use backpressure flow control, and Auto ports use an automatic selection of the two.
Lock:<Disabled> Allows the selected port (or port’s) dynamic MAC address learning to be locked such that new source
MAC addresses cannot be entered into the MAC address table for the locked port. It can be changed by toggling between Disabled and Enabled.
Serial Port Settings
The Serial Port Settings screen allows the configuration of the switch’s serial port and out-of-band
TCP/IP communications using SLIP.
Highlight Serial Port Settings and press Enter.
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Figure 6-18. Serial Port Settings screen
Toggle the Serial port setting field to select either the Console or SLIP protocol.
The following fields can then be set:
Console Settings
Parameter Description
Baud Rate
Data bits
Stop bits
Auto-Logout
Displays the serial bit rate used to communicate with a management station. The console baud rate is 9600 bits per second.
Displays the number of bits that make up a word when communicating with the management station. The console interface uses 8 data bits.
Displays the number of bits used to indicate that a word has been completely transmitted. The console interface uses 1 stop bit.
This sets the time the interface can be idle before the switch automatically logs-out the user. The options are 2
mins, 5 mins, 10 mins, 15 mins, or
Never.
SLIP Settings
Parameter Description
Baud Rate Sets the serial bit rate that will be used to communicate the next time the
Switch is restarted. Applies only when the serial port is being used for out-ofband (SLIP) management; it does not
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DES-3326 Layer 3 Fast Ethernet Switch User’s Guide apply when the port is used for the console port. Available speeds are 2400,
9600, 19200 and 38400 bits per second.
The default setting is 9600.
Interface Name This allows for the naming of the SLIP interface for easy reference.
Local IP Address This is an IP address assigned to the serial port when it is used for SLIP communications.
Remote IP
Address
This is the IP address of the management station that will use the
SLIP protocol to communicate with the switch.
MTU Maximum Transfer Unit – this specifies the maximum packet size in bytes. Can be toggled between 1006 and 1500.
Switch Operation Mode
Putting the switch in IP Routing mode does not – by itself – enable IP routing.
The switch must be configured to use IP interfaces before it is capable of IP routing.
The switch can operate in one of two modes:
1. Layer 2 Only, Support IEEE 802.1Q VLANs. The switching process is based upon the source and destination MAC addresses only. 802.1Q VLANs are supported and the switch is considered as a VLAN-tag aware device.
2. IP Routing, Support IEEE 802.1Q VLANs. The switching process is based upon the IP source and destination addresses, if present. If the IP addresses are not present, the switching process is based upon the MAC addresses (as in Layer 2 above). 802.1Q VLANs are supported and the switch is considered as a VLAN-tag aware device.
The switch must be rebooted when changing the operation mode before the new mode can take effect.
Changing the Switch Operation Mode
To change the switch’s operating mode:
Highlight Switch Settings on the Main Menu and press Enter.
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Figure 6-19. Switch Settings menu
Highlight Switch Operation Mode on the Switch Settings menu and press Enter.
Figure 6-20. Switch Operation Mode screen
The field Select switch operation mode can be toggled using the space bar to one of the two switch operation modes: Layer 2 Only, Support IEEE 802.1Q VLANs and IP Routing, Support IEEE 802.1Q
VLANs.
To make a change in the operation mode of the switch effective, highlight APPLY and press Enter.
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Figure 6-21. Change Mode Confirmation screen
Type y and press Enter. The switch will then save the changes made during the current session and reboot. The switch must be rebooted to change the operation mode.
Menu Changes with Switch Operating Mode
Once the switch is configured for IP Routing (Layer 3 Switching), and rebooted, the Main Menu adds some functions compared to the Layer 2 Only mode. These functions are reflected in additional configuration menus (under the same Main Menu headings as in Layer 2 mode), and the addition of the Layer 3 IP Networking entry. All of the console menus are listed, in order, in the Screen Hierarchy below.
Figure 6-22. Main Menu – Layer 2 Switching Mode
This is the Main Menu when the switch is in Layer 2 mode.
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Figure 6-23. Main Menu – Layer 3 IP Routing Mode
This is the Main Menu when the switch is in Layer 3 mode. Note that the configuration functions necessary for Layer 3 operation have been added to the same Main Menu entries used for Layer 2 mode. Layer 3 IP Networking entry has been added to allow the creation and editing of IP interfaces and the configuration of the RIP and OSPF routing protocols.
Switch Settings
The Switch Settings menu allows for various functions − some of which are configured on different console screens − to be enabled or disabled on the switch (globally), without altering the individual function’s configuration. Thus, the Distance-Vector Multicast Protocol (DVMRP) is configured from the
Setup Layer 3 − IP Networking console menu, but can be enabled or disabled from the Switch
Settings menu − without changing the DVMRP configuration entered in the DVMRP Interface
Configuration menu. (The DVMRP configuration menu is access by highlighting Multicasting from the Main Menu, and then IP Multicasting Settings, and then DVMRP Interface Configuration).
Switch Mode Selection
Switch Settings also allows the switch operating mode to be set. Highlight Switch Settings from the
Main Menu and press Enter. Then highlight Switch Operation Mode and press Enter.
Figure 6-24. Switch Mode Selection screen
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The Select switch operation mode field can be toggled between Layer 2 Only, Support IEEE802.1Q
VLANs (Layer 2 mode) and IP Routing, Support IEEE 802.1Q VLANs (Layer 3 mode). Highlight APPLY and press Enter. The switch will then reboot. When the switch finishes rebooting, it will be in the new operating mode. Configuration changes made while in the Layer 3 mode (and saved using Save
Changes) will be saved while the switch is in Layer 2 mode.
A change mode confirmation screen (shown below) will appear to verify that the operating mode is to be changed. Press Y to continue or N to stop.
Figure 6-25. Change Operating Mode Confirmation screen
Layer 2 Switch Settings
To access the Layer 2 Switch Settings menu, highlight Switch Settings from the Main Menu. Then highlight Layer 2 Switch Settings on the Switch Settings menu and press Enter:
Figure 6-26. Layer 2 Switch Settings menu
The following fields can then be set:
Parameter Description
MAC Address
Aging Time (sec):
Specifies the length of time a learned MAC Address will remain in the forwarding table without being accessed
[300 ] (that is, how long a learned MAC Address is allowed to remain idle). The Aging Time can be set to any value
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IGMP Snooping:
<Disabled>
Switch GVRP
:<Disabled> between 10 and 1,000,000 seconds.
Allows you to set IGMP snooping globally on the switch by selecting Enabled or Disabled.
Allows the Group VLAN Registration Protocol (GVRP) to be globally Enabled or Disabled on the switch.
Switch GMRP
:<Disabled>
Allows the Group Multicast Registration Protocol
(GMRP) to be globally Enabled or Disabled on the switch.
Upper Threshold for Master Ports:
[128]Kpps
This is the number of thousands Broadcast/Multicast packets per second received by the switch – on one of the Master Ports – that will trigger the switch’s reaction to a Broadcast/Multicast storm.
Upper Threshold for Module Ports:
[128]Kpps
This is the number of thousands Broadcast/Multicast packets per second received by the switch – on one of the module ports – that will trigger the switch’s reaction to a Broadcast/Multicast storm.
Broadcast Storm This field can be toggled between Enabled and Disabled
Mode:<Disabled> using the space bar. This enables or disables, globally, the switch’s reaction to Broadcast storms, triggered at the threshold set above.
Multicast Storm
Mode:<Disabled>
This field can be toggled between Enabled and Disabled using the space bar. This enables or disables, globally, the switch’s reaction to Multicast storms, triggered at the threshold set above.
Switch Settings − Layer 3 IP Routing Protocol Settings
The Layer 3 Switch Settings menu only allows the available multicasting
protocols to be enabled or disabled − globally − on the switch.
The multicasting and routing protocols are setup under the Multicasting and the Layer 3 IP
Networking menus − both of which are under the Advanced Setup heading of the Main Menu.
To access the Layer 3 IP Routing Protocol Settings screen, highlight Switch Settings from the Main
Menu. Then highlight Layer 3 IP Routing Protocol Settings on the Switch Settings menu and press
Enter:
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Figure 6-27. Layer 3 IP Routing Protocol Settings screen
The following fields can then be set:
Parameter Description
DVMRP state
:<Disabled>
PIM-DM state:
<Disabled>
Allows the Distance-Vector Multicast
Routing Protocol (DVMRP) to be
Enabled or Disabled globally on the switch.
Allows the Protocol Independent
Multicast − Dense Mode (PIM-DM) multicast routing protocol to be
Enabled or Disabled globally on the switch.
Screen Hierarchy
The contents of the Console Interface are arranged following the structure shown in the table below.
The table is arranged starting with the name of the entry on the Main Menu. The sub-menus start with the name of the first menu, followed by the name of any sub-menus. The sub-menu names are indented. Some menus are available only when the switch is in IP Routing mode. These menus are shown in bold typeface.
Main Menu Entry Sub-Menus
Switch Information
Switch Settings
Switch Information
Remote Management
Setup
Remote Management Setup
Setup Trap Recipients
Switch Settings
Configure Ports
Setup User Accounts
Switch Mode Selection
Layer 2 Switch Settings
Layer 3 IP Routing Protocol Settings
Configure Ports
Setup User Accounts
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Serial Port Settings
Utilities
Network Monitoring
Save Changes
Reboot
Logout
Spanning Tree
Forwarding
Filtering
Priority
Mirroring
Multicasting
Serial Port Settings
Utilities
Upgrade Firmware from TFTP Server
Use Configuration File on TFTP Server
Save Settings to TFTP Server
Save History Log to TFTP Server
Ping Test
BOOTP/DHCP Relay
DNS Relay
Network Monitoring Menu
Port Utilization
Port Error Packets
Port Packet Analysis
Browse MAC Address
Browse IP Address
Routing Table
ARP Table
Default IP Table
OSPF LSDB Table
GVRP
GMRP
Browse Router Port
IGMP Snooping
IP Multicast Forwarding Table
IGMP Group Table
DVMRP Routing Table
Switch History
Save Changes Confirmation Screen (no sub-menus)
Reboot
Reboot
Save Configuration & Reboot
Reboot & Load Factory Default Configuration
Reboot & Load Factory Default Configuration Except IP Address
System Logout (no sub-menus)
Configure Spanning Tree
STP Group Configuration
Port Spanning Tree Settings
Forwarding Menu
Setup Static Unicast MAC Forwarding
Setup Static IP Routes
Setup Static ARP Entries
Filtering Menu
Setup MAC Address Filter
Setup IP Address Filtering
Setup MAC Address Priority
Mirroring Menu
Target Port Selection
Setup Port Mirroring
Multicasting Menu
IGMP Snooping (Layer 2 Only)
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Setup IEEE 802.1Q Multicasting Forwarding
Setup IP Multicasting
Multicast Interface Configuration
IGMP Interface Configuration
IGMP Static Member Configuration
DVMRP Interface Configuration
PIM-DM Interface Configuration
Setup Static Router Port
VLANs VLAN Menu
Edit 802.1Q VLANs
Configure 802.1Q Port Settings
Link Aggregation Link Aggregation
Layer 3 IP Networking Setup Layer 3 – IP Networking
Setup IP Interface
MD5 Key Table Configuration
Setup RIP Configuration
RIP Configuration
Setup RIP
Setup OSPF
OSPF Area Setting
OSPF Interface Configuration
Virtual Interface Configuration
Area Aggregation Configuraion
Route Redistribution Settings
Table 6-2. Console Screen Hierarchy
Advanced Setup
Changing switch operation mode setting changes some of the menus and configuration options for the
Advanced Setup of the switch. The configuration data for each mode is, however, saved when the switch’s operating mode is changed.
Configuring VLANs
The switch allows the assignment of an IP interface to each VLAN, in IP Routing
mode. The VLANs must be configured prior to setting up the IP interfaces.
VLANs by Switch Operating Mode
To create a new 802.1Q VLAN:
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The VLAN menu adds an entry to edit the VLAN definitions and to configure the port settings for IEEE
802.1Q VLAN support. Highlight VLANs from the Main Menu and press Enter.
Figure 6-28. VLAN Menu
To create an 802.1Q VLAN, highlight Edit 802.1Q VLANs and press Enter:
Figure 6-29. Edit 802.1Q VLANs screen
Action:
<Add/Modify>
VID#
Membership
(E/F/-):
E
Parameter
VLAN Name:
Description
This field can be toggled using the space bar between
Add/Modify and Delete. Add/Modify allows for the creation of a new VLAN or for changes to an existing VLAN. Delete allows for the deletion of an existing VLAN from the switch.
Allows the entry of the VLAN ID (VID) of an existing VLAN.
VLANs can be identified by either the VID or the VLAN name.
Allows the entry of the name of an existing VLAN. VLANs can be identified by either the VID or the VLAN name.
Allows an individual port to be specified as an Egress,
Forbidden, or Non-member of a VLAN.
Egress Member - specifies the port as being a static member of the VLAN Egress Member Ports are ports that will be
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F
-
Tagging (U/T):
U
T of the VLAN. Egress Member Ports are ports that will be transmitting traffic for the VLAN. These ports can be either tagged or untagged.
Forbidden Non-Member - specifies the port as not being a member of the VLAN and that the port is forbidden from becoming a member of the VLAN dynamically.
Non-Member - specifies the port as not being a member of the VLAN, but the port can become a member of the VLAN dynamically.
Allows an individual port to be specified as either Tagging or
Untagging.
Untagging - specifies the port as an Untagging member of the
VLAN. When an untagged packet is transmitted by the port, the packet header remains unchanged. When a tagged packet exits the port, the tag is stripped and the packet is changed to an untagged packet.
Tagging - specifies the port as a Tagging member of the
VLAN. When an untagged packet is transmitted by the port, the packet header is changed to include the 32-bit tag associated with the PVID (Port VLAN Identifier – see below).
When a tagged packet exits the port, the packet header is unchanged.
To create an 802.1Q VLAN, toggle the Action field to Add/Modify using the space bar. Enter a VLAN ID number in the VID# field and a name for the new VLAN in the VLAN Name field.
Choose which ports will be members of the new VLAN and enter their membership status in the
Membership (E/F/-) field. The status indicators of the individual ports can be entered directly from the keyboard or toggled using the space bar. Moving between the status indicators of the individual ports is accomplished using the arrow keys.
To set the 802.1Q VLAN membership status of a port:
To enter the 802.1Q VLAN status for a port, highlight the first field of Membership (E/F/-). Each port’s
802.1Q VLAN membership can be set individually by highlighting the port’s entry using the arrow keys, and then toggling between E, F, or – using the space bar.
Next, determine which of the ports that are members of the new VLAN will be Tagged or Untagged ports.
To set a port as either a Tagged or an Untagged port:
Highlight the first field of Tagging (U/T) field. Each port’s state can be set by highlighting the port’s entry using the arrow keys and then toggling between U or T using the space bar.
If the port is attached to a device that is not IEEE 802.1Q VLAN compliant (VLAN-tag unaware), then the port should be set to U – Untagged.
If the port is attached to a device that is IEEE 802.1Q VLAN compliant, (VLAN-tag aware), then the port should be set to T – Tagged.
Press APPLY to make the additions/deletions effective for the current session. To make enter the IP
Interfaces into Non-volatile RAM, highlight Save Changes from the Main Menu and press Enter.
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In the following example screen, the VLAN “evilJulius” - VID# 2 – has been added. Ports 1, 2, 12, 14,
17, 25, and 26 are Egress ports (static members of “evilJulius”. Ports 5, 6, and 7 are Forbidden ports
(non-members and are not allowed to join the VLAN “evilJulius” dynamically.
Example Edit 802.1Q VLAN screen:
Figure 6-30. Edit 802.1Q VLANs screen
To configure the member ports of an 802.1Q VLAN:
Highlight VLANs from the Main Menu and press Enter.
Figure 6-31. VLAN Menu
Highlight Configure 802.1Q Port Settings and press Enter:
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Figure 6-32. Configure 802.1Q Port Settings screen
The following fields can be set:
Parameter Description
Module:
Configure Port from [ ] to [ ]
This allows the entry of a contiguous range of port numbers to be configured.
PVID#[ ]
This allows you to toggle between the Base Unit and Slot-1.
Port VLAN Identifier – is a classification mechanism that associates a port with a specific
VLAN and is used to make forwarding decisions for untagged packets received by the port. For example, if port #2 is assigned a PVID of 3, then all untagged packets received on port #2 will be assigned to VLAN 3. This number is generally the same as the VID# number assigned to the port in the Edit 802.1Q VLANs menu above.
Ingress
Filter:<Off>
GVRP:<Off>
This field can be toggled using the space bar between On and Off. On enables the port to compare the VID tag of an incoming packet with the PVID number assigned to the port. If the two are different, the port filters (drops) the packet.
Off disables Ingress filtering.
Group VLAN Registration Protocol (GVRP) – this enables the port to dynamically become a member of a VLAN.
GMRP:<Off> Group Multicast Registration Protocol (GMRP) − this enables the port to dynamically become a member of a multicast group.
Each port can be configured to use an Ingress Filter, to enable or disable GVRP. The ports to be configured in a given session can be identified by either entering a range of port numbers or by entering the PVID#.
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To configure a port’s 802.1Q VLAN settings:
Highlight the Configure Port from [ ] to [ ] field and enter the range of port numbers you want to configure. As an alternative you can use the arrow keys to highlight the PVID# field and enter the PVID for the VLAN’s member ports you want to configure.
Use the arrow keys to highlight the remaining fields and the space bar to toggle between On and Off.
To edit an existing 802.1Q VLAN:
Highlight VLANs on the Main Menu and press Enter:
Figure 6-33. VLAN Menu
To edit an existing 802.1Q VLAN, highlight Edit 802.1Q VLANs and press Enter:
Figure 6-34. Edit 802.1Q VLANs screen
To edit an existing 802.1Q VLAN, highlight the Action field and toggle between Add/Modify and Delete.
In the Add/Modify mode, both individual entrees to a selected VLAN and entire VLANs can be added. In the Delete mode, entire VLANs can be deleted. VLANs to be edited can be selected by either the VID# field or the VLAN Name fields. Enter either the VID or the VLAN Name for the 802.1Q VLAN you want to edit and press Enter.
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To delete an entire VLAN, toggle the Action field to Delete, enter either the VID or the VLAN Name in the appropriate field and press Enter. Highlight Apply and press Enter. The selected VLAN will be deleted. To enter the change into Non-volatile RAM, select Save Changes from the Main Menu.
802.1Q VLANs are edited by specifying which ports will be Egress Members, Forbidden non-members or non-members.
The ports are further set to be either a Tagged or an Untagged port.
To edit the 802.1Q VLAN membership of a port:
Highlight the first field of Membership (E/F/-). Each port’s 802.1Q VLAN membership can be set individually by highlighting the port’s entry using the arrow keys, and then toggling between E, F, or – using the space bar.
To edit a port’s Tagged or Untagged status:
Highlight the first field of Tagging (U/T) field. Each port’s state can be set by highlighting the port’s entry using the arrow keys and then toggling between U or T using the space bar.
If the port is attached to a device that is not IEEE 802.1Q VLAN compliant (VLAN-tag unaware), then the port should be set to U – Untagged.
If the port is attached to a device that is IEEE 802.1Q VLAN compliant, (VLAN-tag aware), then the port should be set to T – Tagged.
To configure a port’s 802.1Q VLAN settings:
Highlight the Configure Port# field and enter the port number of the port you want to configure. Use the arrow keys to highlight the PVID# field and enter the PVID for the port.
Use the arrow keys to highlight the remaining fields and the space bar to toggle between Enable and
Disable.
Setting Up IP Interfaces
A VLAN that does not have a corresponding IP interface defined for it, will function as a Layer 2 Only VLAN – regardless of the Switch Operation mode.
Each VLAN must be configured prior to setting up the VLAN’s corresponding IP interface.
An example is presented below:
VLAN Name
System (default)
Engineering
Marketing
Finance
Sales
VID
3
4
1
2
5
Switch Ports
5, 6, 7, 8, 21, 22, 23, 24
9, 10, 11, 12
13, 14, 15, 16
17, 18, 19, 20
1, 2, 3, 4
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Table 6-3. VLAN Example – Assigned Ports
In this case, 6 IP interfaces are required, so a CIDR notation of 10.32.0.0/11 (or a 11-bit) addressing scheme will work. This addressing scheme will give a subnet mask of
11111111.11100000.00000000.00000000 (binary) or 255.224.0.0 (decimal).
Using a 10.xxx.xxx.xxx IP address notation, the above example would give 6 network addresses and 6 subnets.
Any IP address from the allowed range of IP addresses for each subnet can be chosen as an IP address for an IP interface on the switch.
For this example, we have chosen the next IP address above the network address for the IP interface’s
IP Address:
VLAN Name VID Network Number IP Address
System (default) 1 10.32.0.0 10.32.0.1
Table 6-4. VLAN Example – Assigned IP Interfaces
The 6 IP interfaces, each with an IP address (listed in the table above), and a subnet mask of
255.224.0.0 can be entered into the Setup IP Interface menu.
To setup IP Interfaces on the switch:
Highlight Layer 3 IP Networking from the Main Menu and press Enter.
Figure 6-35. Layer 3 - Main Menu
Highlight Layer 3 IP Networking from the Main Menu and press Enter.
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Figure 6-36. Setup Layer 3 – IP Networking menu
Highlight Setup IP Interface and press Enter.
Figure 6-37. Layer 3 – IP Networking Menu
Toggle the Action field to Add/Modify. Choose a name for the interface to be added and enter it in the
Interface Name field. The corresponding VLAN ID must also be entered in the VID field. Enter the interface’s IP address and subnet mask in the corresponding fields. Toggle the Active field to Yes, highlight APPLY and press Enter to make the IP interface effective. Use Save Changes from the Main
Menu to enter the changes into NV-RAM.
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The following fields can be set:
Parameter Description
Action:<Add/Modify
>
This field can be toggled using the space bar between Add/Modify and Delete. Add/Modify allows for the creation of a new IP interface or changes to an existing IP interface. Delete allows for the deletion of an existing IP interface from the switch.
Interface Name:[ ] This field allows the entry of a name for the IP interface. The default IP interface is named
“System”.
IP Address:[ ] This field allows the entry of an IP address to be assigned to this IP interface.
Subnet Mask:[ ] This field allows the entry of a subnet mask to be applied to this IP interface.
Active:<Yes>
VID:[ ]
This field is toggled between Yes and No using the space bar. This entry determines whether the IP interface will be active or not.
This field allows the entry of the VLAN ID number for the VLAN the IP interface belongs to.
Layer 3 IP Networking
To access the Layer 3 IP Networking menus, highlight Layer 3 IP Networking from the Main Menu and press Enter.
Figure 6-38. Layer 3 – IP Networking menu
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Setup Routing Information Protocol (RIP)
If an IP Interface is created while RIP is enabled, the TX Mode default will be V2 Only and the RX Mode default will be V1 and V2.
To access the Setup RIP Configuration menu, highlight Setup RIP Configuration from the Setup
Layer 3 IP − Networking menu and press Enter.
Figure 6-39. RIP Configuration menu
The RIP Configuration menu allows RIP to be globally enabled and disabled on the switch without changing its configuration. Toggle the RIP Status field between Enabled and Disabled using the space bar.
To configure RIP on the switch, highlight Setup RIP from the RIP Configuration menu and press
Enter.
Figure 6-40. Setup RIP screen
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The following fields can be set:
Parameter
Interface name:
[ ]
TX Mode
<Disabled>
RX Mode
<Disabled>
Authentication:
Disabled
Password:
Description
The name of the IP interface on which RIP is to be setup.
This interface must be previously configured on the switch.
Toggle among Disabled, V1 Only, V1 Compatible, and V2
Only. This entry specifies which version of the RIP protocol will be used to transmit RIP packets. Disabled prevents the transmission of RIP packets.
Toggle among Disabled, V1 Only, V2 Only, and V1 and
V2. This entry specifies which version of the RIP protocol will be used to interpret received RIP packets. Disabled prevents the reception of RIP packets.
Toggle between Enabled and Disabled. When authentication is enabled, a password is used to authenticate communication between routers on the network. Authentication is only supported when RIP is in
V1 Compatible or V2 only mode.
A password to be used to authenticate communication between routers on the network.
Setup Open Shortest Path First (OSPF)
MD5 Key Table Configuration
To access the MD5 Key Table Configuration screen, highlight MD5 Key Table Configuration on the menu above, and press Enter.
Figure 6-41. MD5 Key Table Configuration screen
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This screen allows the entry of a 16-character Message Digest (version 5 − MD5) key that can be used to authenticate every packet exchanged between OSPF routers. It is used as a security mechanism to limit the exchange of network topology information to the OSPF routing domain.
The following fields can be set:
Parameter Description
Action:
<Add/Modify>
Key ID:[ ]
Key:[ ]
This field can be toggled using the space bar between Add/Modify and
Delete. Add/Modify allows for the creation of a new MD5 Key or changes to an existing MD5 Key.
Delete allows for the deletion of an existing MD5 Key.
A number from 1 to 255 used to identify the MD5 Key.
An alphanumeric string of between 1 and 16 case-sensitive characters used to generate the Message Digest which is in turn, used to authenticate OSPF packets within the OSPF routing domain.
Setup RIP Configuration
To access the Setup RIP Configuration menu, highlight Setup RIP Configuration from the Setup
Layer 3 IP − Networking menu and press Enter.
Figure 6-42. RIP Configuration menu
The RIP Configuration menu allows RIP to be globally enabled and disabled on the switch without changing its configuration.
To configure RIP on the switch, highlight Setup RIP from the RIP Configuration menu and press
Enter.
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Figure 6-43. Setup RIP screen
The following fields can be set:
Parameter Description
Interface
name:[System ]
TX Mode<Disabled> Toggle among Disabled, V1 Only, V1
Compatible, and V2 Only. This entry specifies which version of the RIP protocol will be used to transmit RIP packets. Disabled prevents the transmission of RIP packets.
RX
Mode<Disabled>
Toggle among Disabled, V1 Only, V2
Only, and V1 and V2. This entry specifies which version of the RIP protocol will be used to interpret received RIP packets. Disabled prevents the reception of RIP packets.
Authentication: Toggle between Enabled and
Disabled. When authentication is enabled, a password is used to authenticate communication between routers on the network.
Authentication is only supported when RIP is in V1 Compatible or V2
only mode.
Password:
The name of the IP interface on which RIP is to be setup. This interface must be previously configured on the switch.
A password to be used to authenticate communication between routers on the network.
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Setup OSPF
Highlight Setup OSPF from the Setup Layer 3 - IP Networking menu and press Enter to access the
Setup OSPF menu.
Figure 6-44. Setup OSPF menu
Each menu item is explained as follows:
• OSPF Area Setting – Allows the configuration of sub-domains called OSPF areas and the designating them as either Normal or Stub areas. Normal areas allow the advertisement of external routes and stub areas do not.
• OSPF Interface Configuration – Allows the entry of OSPF Interfaces that correspond to IP interfaces defined previously on the switch.
• Virtual Interface Configuration – Allows the definition of areas that allow links with outside routers to access the OSPF backbone.
• Area Aggregation Configuration – Allows OSPF areas to be represented by their networknumber (network address) and subnet mask. In addition, the type of Link-State Database advertisements can be specified for each area.
On the Setup OSPF menu itself, an OSPF Router ID for the switch is entered. This is a 32-bit number
(in the form of an IP address) that uniquely identifies the switch as an OSPF router on the network.
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The following fields can be set:
Parameter Description
OSPF Router
ID:[ ]
A 32-bit number (in the form of an IP address − xxx.xxx.xxx.xxx) that uniquely identifies the switch in the
OSPF domain. It is common to assign the highest IP address assigned to the switch (router). In this case, it would be 10.255.255.255, but any unique 32-bit number will do. If 0.0.0.0 is entered, the highest IP address assigned to the switch will become the OSPF Route ID.
Current Router
ID:[ ]
Displays the OSPF Route ID currently in use by the switch.
This Route ID is displayed as a convenience to the user when changing the switch’s OSPF Route ID.
AS Border Router Autonomous System Border Router − displays whether or not the switch is configured as an AS Border Router.
State:<Disabled> Allows OSPF to be enabled or disabled globally on the switch without changing the OSPF configuration.
OSPF Area Setting
This menu allows the configuration of OSPF Area IDs and to designate these areas as either Normal or
Stub. Normal OSPF areas allow Link-State Database (LSDB) advertisements of routes to networks that are external to the area. Stub areas do not allow the LSDB advertisement of external routes. Stub areas use a default summary external route (0.0.0.0) to reach external destination.
To configure the OSPF areas for the switch, highlight OSPF Area Setting on the Setup OSPF menu and press Enter.
Figure 6-45. OSPF Area Setting screen
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The following fields can be set:
Parameter Description
Action:<Add/Modify
>
Area ID:[0.0.0.0 ]
Type:<Normal>
This field can be toggled using the space bar between
Add/Modify and Delete. Add/Modify allows for the creation of a new OSPF Area or changes to an existing
OSPF Area. Delete allows for the deletion of an existing
OSPF Area.
A 32-bit number in the form of an IP address
(xxx.xxx.xxx.xxx) that uniquely identifies the OSPF area in the OSPF domain.
This field can be toggled between Normal and Stub using the space bar. When it is toggled to Stub, additional fields appear − Stub Import Summary LSA, and Stub Default Cost.
Stub Import
Summary LSA:<Yes>
Displays whether or not the selected Area will allow
Summary Link-State Advertisements (Summary LSAs) to be imported into the area from other areas.
Stub Default
Cost:[ 0 ]
Displays the default cost for the route to the stub of between 0 and 65,535. The default is None (0).
OSPF Interface Configuration
This screen allows the association of IP interfaces with OSPF areas. The IP interfaces must have been previously defined on the switch.
To configure an OSPF interface, highlight OSPF Interface Configuration from the Setup OSPF menu and press Enter.
Figure 6-46. OSPF Interface Configuration screen
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The following fields can be set:
Parameter Description
Interface
Name:[System ]
Area ID:[0.0.0.0]
Allows the entry of the name of an IP interface previously configured on the switch.
Allows the entry of an OSPF Area ID configured above.
Router Priority:[1] Allows the entry of a number between 0 and 255 representing the OSPF priority of the selected area. If a
Router Priority of 0 is selected, the switch cannot be elected as the Designated Router for the network.
Hello Interval:[10 ] Allows the specification of the interval between the transmission of OSPF Hello packets, in seconds. Between 5 and 65535 seconds can be specified. The Hello Interval, Dead
Interval, Authorization Type, and Authorization Key should be the same for all routers on the same network.
Dead Interval:[40 ] Allows the specification of the length of time between the receipt of Hello packets from a neighbor router before the selected area declares that router down. An interval between
5 and 65535 seconds can be specified. The Dead Interval must be evenly divisible by the Hello Interval.
State:<Disabled> Allows the OSPF interface to be disabled for the selected area without changing the configuration for that area.
Auth. Type:<None> This field can be toggled between None, Simple, and MD5 using the space bar. This allows a choice of authorization schemes for OSPF packets that may be exchanged over the
OSPF routing domain. None specifies no authorization.
Simple uses a simple password to determine if the packets are from an authorized OSPF router. When Simple is selected, the Auth Key field allows the entry of a 8 character password that must be the same as a password configured on a neighbor OSPF router. MD5 uses a cryptographic key entered in the MD5 Key Table Configuration menu. When
MD5 is selected, the Auth Key ID field allows the specification of the Key ID as defined in the MD5 configuration above. This must be the same MD5 Key as used by the neighboring router.
Auth. Key:[ ]
Metric:[1 ]
MD5 uses a cryptographic key entered in the MD5 Key
Table Configuration screen. When MD5 is selected, the
Auth. Key ID field allows the specification of the Key ID as defined in the MD5 configuration above. This must be the same MD5 Key as used by the neighboring router.
This field allows the entry of a number between 1 and 65,535 that is representative of the OSPF cost of reaching the selected OSPF interface. The default metric is 1.
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Virtual Interface Configuration
Virtual Interfaces are used by OSPF to link areas that do not have a physical connection to the backbone (also called Area 0) or to link areas of the backbone itself that are discontinuous. This allows routing information to flow from an area that is physically disconnected from area 0 into area 0 by configuring an interface across one of the areas previously defined above.
To configure an OSPF Virtual Interface, highlight Virtual Interface Configuration and press Enter.
Figure 6-47. Virtual Interface Configuration screen
Note that the Hello Interval (Hello-Intv.), Dead Interval (Dead-Intv.), and Authorization Type (Auth.
Type) must be the same for the Transit Area and the remote area’s Neighbor Router.
The following fields can be set:
Parameter Description
Action:<Add/Modify
>
Transit Area
ID:[ ]
This field can be toggled using the space bar between Add/Modify and
Delete. Add/Modify allows for the creation of a new OSPF Virtual
Interface or changes to an existing
OSPF Virtual Interface. Delete allows for the deletion of an existing OSPF
Virtual Interface.
Allows the entry of an OSPF Area ID
− previously defined on the switch − that allows a remote area to communicate with the backbone
(area 0). A Transit Area cannot be a
Stub Area or a Backbone.
Neighbor Router ID:[
]
The OSPF router ID for the remote router. This is a 32-bit number in the form of an IP address
(xxx.xxx.xxx.xxx) that uniquely identifies the remote area’s Area
Border Router.
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Status Displays the current status (UP or
DOWN) of the corresponding OSPF
Virtual Interface.
Area Aggregation Configuration
Area Aggregation allows all of the routing information that may be contained within an area to be aggregated into a summary LSDB advertisement of just the network address and subnet mask. This allows for a reduction in the volume of LSDB advertisement traffic as well as a reduction in the memory overhead in the switch used to maintain routing tables.
To aggregate routing information contained within an OSPF area, highlight Area Aggregation
Configuration from the Setup OSPF menu and press Enter.
Figure 6-48. Area Aggregation Configuration screen
The following fields can be set:
Parameter Description
Action:<Add/Modify
>
Area ID:[ ]
This field can be toggled using the space bar between
Add/Modify and Delete. Add/Modify allows for the creation of a new OSPF Area Aggregation or changes to an existing
OSPF Area Aggregation. Delete allows for the deletion of an existing OSPF Area Aggregation.
Allows the entry the OSPF Area ID for which the routing information will be aggregated. This Area ID must be previously defined on the switch.
Network Number:[
]
Sometimes called the Network Address. The 32-bit number in the form of an IP address that uniquely identifies the network that corresponds to the OSPF Area above.
Network This is the netmask associated with the Network Number above.
Netmask:[ ]
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Advertisement:
<Yes>
This field can be toggled between Yes and No using the space bar. It determines whether or not the selected OSPF
Area will advertise it’s summary LSDB (Network-Number and Network-Mask) or not.
Route Redistribution Settings
Route redistribution allows routers on the network that are running different routing protocols to exchange routing information. This is accomplished by comparing the routes stored in the various router’s routing tables and assigning appropriate metrics. This information is then exchanged among the various routers according to the individual routers current routing protocol. The DES-3326 can redistribute routing information between the OSPF and RIP routing protocols to all routers on the network that are running OSPF or RIP. Routing information entered into the Static Routing Table on the local DES-3326 switch is also redistributed.
Figure 6-49. Route Redistribution Settings screen
The following fields can be set:
Parameter Description
Action:
<Add/Modify>
Source
Protocol:[ ]
Destination
Protocol:[ ]
Metric Type:[
]
This field can be toggled using the space bar between
Add/Modify and Delete. Add/Modify allows for the creation of a new OSPF Area Aggregation or changes to an existing
OSPF Area Aggregation. Delete allows for the deletion of an existing OSPF Area Aggregation.
Allows the selection of the protocol of the source device.
Available choices are RIP, OSPF, or Static.
Allows the selection of the protocol of the destination device. Available choices are RIP and OSPF.
Allows the selection of one of two methods for calculating the metric value. Type-1 calculates the metric (for RIP to
OSPF) by adding the destination’s interface cost to the metric entered in the Metric field. Type-2 uses the metric entered in the Metric field without change. This field
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Metric:[ ]
Multicasting
applies only when the destination field is OSPF.
Allows the entry of an OSPF interface cost. This is analogous to a Hop Count in the RIP routing protocol.
Layer 2 Multicast Setup
To setup Multicasting on the switch, when the switch is in Layer 2 operating mode, highlight
Multicasting from the Main Menu and press Enter.
Figure 6-50. Multicasting Menu
IGMP Snooping Settings
To configure IGMP Snooping, highlight IGMP Snooping Settings from the Multicasting Menu and press Enter.
Figure 6-51. IGMP Snooping Settings screen
IGMP Snooping can be globally enabled or disabled from the IGMP Snooping Settings screen.
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To configure IGMP Snooping:
Toggle the Switch IGMP Snooping field to Enabled. Toggle the Querier State field to the appropriate choice between Non-Querier, V1-Querier, and V2-Querier to determine the version of IGMP that is used in your network. A value between 2 and 255 can be entered for the Robustness Variable (default is 2).
The Query Interval can be set between 1 and 65500 seconds (default is 125 seconds). This sets the time between IGMP queries. The Max Response allows a setting between 1 and 25 seconds (default is
10) and specifies the maximum amount of time allowed before sending a response report.
Highlight APPLY and press Enter to make the settings effective.
The following fields can be set:
Parameter Description
Switch IGMP
Snooping:
<Disabled>
Querier State:<Non-
Querier>
Robustness
Variable:[ 2]
This field can be toggled using the space bar between Disabled and Enabled. This is used to enable or disable IGMP Snooping, globally, on the switch.
This field can be toggled between Non-Querier, V1-
Querier, and V2-Querier. This is used to specify the
IGMP version (1 or 2) that will be used by the
IGMP interface when making queries.
A tuning variable to allow for sub-networks that are expected to lose a large number of packets. A value between 2 and 255 can be entered, with larger values being specified for sub-networks that are expected to lose larger numbers of packets.
Query Interval:[125
]
Allows the entry of a value between 1 and 65535 seconds, with a default of 125 seconds. This specifies the length of time between sending IGMP queries.
Max. Response:[10] Sets the maximum amount of time allowed before sending an IGMP response report. A value between
1 and 25 seconds can be entered, with a default of
10 seconds.
IEEE 802.1Q Multicast Forwarding
To edit the IEEE802.1 Multicast Forwarding settings, highlight IEEE802.1Q Multicast Forwarding
Settings from the Multicasting Menu and press Enter.
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Figure 6-52. Setup IEEE 802.1Q Multicast Forwarding screen
When the switch is in Layer 2 operating mode, IEEE 802.1Q multicast forwarding allows the static entry of multicast MAC addresses, which will be sources of multicast packets, and switch port numbers, to which these multicast packets will be forwarded. The ports that can be chosen as the destination for multicast packets from the above MAC multicast address, are limited to the ports belonging to the VLAN that corresponds to the VID entered in the VID field.
Each port of a given VLAN can be configured as an egress member, a forbidden non-member, or as a non-member of the multicast group that will receive multicast packets from the multicast MAC address, by toggling the entry below each port of the VLAN to the appropriate code.
Parameter Description
Action:
<Add/Modify>
VID:[ ]
The field can be toggled between Add/Modify and Delete using the space bar. To add a new entry to the multicast forwarding table, select Add/Modify and enter the VID of the VLAN that will be receiving the multicast packets.
Enter the MAC address of the multicast source, and then enter the member ports. Delete allows for the deletion of a previously made entry.
Allows the specification of the VLAN ID (VID) of the VLAN the static multicast group member belongs to.
Allows the entry of the MAC address of a static multicast group member. Multicast MAC
Address:[ ]
(E/F/-): [ ][ ][ ]
E
F
-
To set a port’s multicast group membership status, highlight the first field of. Each port’s multicast group membership can be set individually by highlighting the port’s entry using the arrow keys, and then toggling between E, F, or – using the space bar.
Egress Member – specifies the port as being a static member of the multicast group. Egress Member Ports are ports that will be transmitting traffic for the multicast group.
Forbidden Non-Member - specifies the port as not being a member of the multicast group and that the port is forbidden from becoming a member of the multicast group dynamically.
Non-Member - specifies the port as not being a member of the multicast group, but the port can become a member of the multicast group dynamically.
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Static Router Port Settings
A static router port is a port that has a multicast router attached to it. Generally, this router would have a connection to a WAN or to the Internet. Establishing a router port will allow multicast packets coming from the router to be propagated through the network, as well as allowing multicast messages
(IGMP) coming from the network to be propagated to the router.
A router port has the following behavior:
• All IGMP Report packets will be forwarded to the router port.
• IGMP queries (from the router port) will be flooded to all ports.
• All UDP multicast packets will be forwarded to the router port. Because routers do not send
IGMP reports or implement IGMP snooping, a multicast router connected to the router port of the Layer 3 switch would not be able to receive UDP data streams unless the UDP multicast packets were all forwarded to the router port.
• A router port will be dynamically configured when IGMP query packets, RIPv2 multicast,
DVMRP multicast, PIM-DM multicast packets are detected flowing into a port.
To setup a static router port, highlight Static Router Port Settings from the Multicasting Menu and press Enter.
Figure 6-53. Setup Static Router Port screen
Parameter
Action:
<Add/Modify>
Router Port (M/-):
[ ][ ][ ]
Description
This field can be toggled between Add/Modify and Delete using the space bar. To add a port to the static router port table, select Add/Modify and enter the VID of the VLAN the router port will belong to. Delete allows for the deletion of a previously made entry.
Each port can be set individually as a router port by highlighting the port’s entry using the arrow keys, and then toggling between M and – using the space bar. M indicates a port is a member of the static group of router ports. – indicates a port is not a static member.
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Layer 3 Multicasting
When the switch is in IP Routing mode, several functions supporting IP multicasting are added to the
Multicasting menu. These additional functions can be configured under the IP Multicasting Settings menu.
With the switch in IP Routing mode, highlight Multicasting from the Main Menu and press Enter.
Figure 6-54. Multicasting Menu
Setup IP Multicast
To setup IP multicasting on the switch:
Highlight IP Multicasting Settings from the Multicasting Menu and press Enter.
Highlight Multicast Interface Configuration from the Setup IP Multicast menu and press Enter.
Figure 6-55. Setup IP Multicast menu
Multicast Interface Configuration
To configure the multicast interface, highlight Multicast Interface Configuration and press Enter.
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Figure 6-56. Multicast Interface Configuration screen
This menu allows the assignment of a multicast routing protocol to an IP interface. The IP interface must have been previously configured on the switch.
In addition, IGMP may be enabled or disabled for the selected IP interface.
The available multicast protocols are the Protocol Independent Multicast – Dense Mode (PIM-DM), and the Distance-Vector Multicast Routing Protocol (DVMRP).
INACT is not a multicast routing protocol. It is used to make a given interface inactive for IP Multicast routing and can still route IP traffic.
Parameter Description
Interface Name:[
]
Allows the entry of the name of the
IP interface that is to be configured for multicasting. This must be a previously configured IP interface.
IGMP: <Enabled> This field can be toggled between
Enabled and Disabled using the space bar. This will enable or disable
IGMP for the IP interface entered above.
Protocol: <INACT> This field can be toggled between
Protocol Independent Multicasting
– Dense Mode (PIMDM), Distance
Vector Multicasting Routing
Protocol (DVMRP), and INACT
(inactive). INACT is not a multicast routing protocol. It is used to make a given interface inactive for IP
Multicast routing yet can still route
IP traffic.
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IGMP Interface Configuration
Figure 6-57. IGMP Interface Configuration screen
This menu allows the configuration of IGMP for each IP interface configured on the switch. IGMP can be configured as Version 1 or 2 by toggling the Ver field. The length of time between queries can be varied by entering a value between 1 and 65,535 seconds in the Query field. The maximum length of time between the receipt of a query and the sending of an IGMP response report can be varied by entering a value in the Max Response field.
The Robustness Var field allows IGMP to be ‘tuned’ for sub-networks that are expected to lose a lot of packets. A high value (max. 255) for the robustness variable will help compensate for ‘lossy’ subnetworks. A low value (min. 2) should be used for less ‘lossy’ sub-networks.
Parameter Description
Interface Name:[ ] Allows the entry of the name of the IP interface that is to be configured for IGMP. This must be a previously configured IP interface.
Ver:<2> Can be toggled between 1 and 2. This determines the
IGMP version (1 or 2) that will be used to interpret IGMP queries on the interface.
Robustness Var:[ 2] A tuning variable to allow for subnetworks that are expected to lose a large number of packets. A value between 2 and 255 can be entered, with larger values being specified for subnets that are expected to lose larger numbers of packets.
Query:[125 ] Allows the entry of a value between 1 and 65535 seconds, with a default of 125 seconds. This specifies the length of time between sending IGMP queries.
Max Response:[10] Sets the maximum amount of time allowed before sending an IGMP response report. A value between 1 and 25 seconds can be entered, with a default of 10 seconds.
IP Address: Displays the IP address corresponding to the IP interface name entered above
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DVMRP
To configure DVMRP for an IP interface, highlight DVMRP Interface Configuration from the Setup IP
Multicast menu and press Enter.
Figure 6-58. DVMRP Interface Configuration screen
This menu allows the Distance-Vector Multicast Routing Protocol to be configured for each IP interface defined on the switch.
The Distance Vector Multicast Routing Protocol (DVMRP) is a hop-based method of building multicast delivery trees from multicast sources to all nodes of a network. Because the delivery trees are ‘pruned’ and ‘shortest path’, DVMRP is relatively efficient. Because multicast group membership information is forwarded by a distance-vector algorithm, propagation is slow. DVMRP is optimized for high delay (high latency) relatively low bandwidth networks, and can be considered as a ‘best-effort’ multicasting protocol.
DVMRP resembles the Routing Information Protocol (RIP), but is extended for multicast delivery. It relies upon RIP hop counts to calculate ‘shortest paths’ back to the source of a multicast message, but defines a ‘route cost’ to calculate which branches of a multicast delivery tree should be ‘pruned’ – once the delivery tree is established.
When a sender initiates a multicast, DVMRP initially assumes that all users on the network will want to receive the multicast message. When an adjacent router receives the message, it checks its unicast routing table to determine the interface that gives the shortest path (lowest cost) back to the source. If the multicast was received over the shortest path, then the adjacent router enters the information into its tables and forwards the message. If the message is not received on the shortest path back to the source, the message is dropped.
Route cost is a relative number that is used by DVMRP to calculate which branches of a multicast delivery tree should be ‘pruned’. The ‘cost’ is relative to other costs assigned to other DVMRP routes throughout the network.
The higher the route cost, the lower the probability that the current route will be chosen to be an active branch of the multicast delivery tree (not ‘pruned’) – if there is an alternative route.
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The following fields can be set:
Parameter
Interface Name:
[ ]
NBR Report
Timer:[35 ]
Route Cost:[1 ]
State:<Disabled>
IP Address:
Probe Interval:
[10 ]
Description
Allows the entry of the name of the IP interface for which
DVMRP is to be configured. This must be a previously defined IP interface.
This field allows an entry between 1 and 65,535 seconds and defines the time period for DVMRP will hold Neighbor
Router reports before issuing poison route messages. The default is 35 seconds.
This field allows an entry between 1 and 255 and defines the route cost for the IP interface. The DVMRP route cost is a relative number that represents the real cost of using this route in the construction of a multicast delivery tree. It is similar to, but not defined as, the hop count in RIP. The default cost is 1.
This field can be toggled between Enabled and Disabled and enables or disables DVMRP for the IP interface. The default is Disabled.
Displays the IP address corresponding to the IP Interface name entered above.
The Probe Interval field allows an entry between 1 and
65,535 seconds and defines the interval between ‘probes’.
The default is 10.
PIM-DM
To configure PIMDM for an IP interface:
Highlight PIMDM Interface Configuration from the Setup IP Multicast menu and press Enter.
Figure 6-59. PIM-DM Interface Configuration screen
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The Protocol Independent Multicast – Dense Mode (PIM-DM) protocol should be used in networks with a low delay (low latency) and high bandwidth as PIM-DM is optimized to guarantee delivery of multicast packets, not to reduce overhead.
The PIM-DM multicast routing protocol is assumes that all downstream routers want to receive multicast messages and relies upon explicit prune messages from downstream routers to remove branches from the multicast delivery tree that do not contain multicast group members.
PIM-DM has no explicit ‘join’ messages. It relies upon periodic flooding of multicast messages to all interfaces and then either waiting for a timer to expire (the Join/Prune Interval) or for the downstream routers to transmit explicit ‘prune’ messages indicating that there are no multicast members on their respective branches. PIM-DM then removes these branches (‘prunes’ them) from the multicast delivery tree.
Because a member of a pruned branch of a multicast delivery tree may want to join a multicast delivery group (at some point in the future), the protocol periodically removes the ‘prune’ information from its database and floods multicast messages to all interfaces on that branch. The interval for removing
‘prune’ information is the Join/Prune Interval.
The following fields can be set:
Parameter Description
Interface Name:
[ ]
IP Address
Allows the entry of the name of the
IP interface for which PIM-DM is to be configured. This must be a previously defined IP interface.
Displays the IP address for the IP interface named above.
Hello Interval:[30
]
This field allows an entry of between
1 and 18724 seconds and determines the interval between sending Hello packets to other routers on the network. The default is 30 seconds.
Join/Prune
Interval:[60 ]
State:<Disabled>
This field allows an entry of between1 and 18724 seconds. The default is 60 seconds.
This field can be toggled between
Enabled and Disabled using the space bar, and is used to enable or disable PIM-DM for the IP interface.
The default is Disabled.
Port Mirroring
To configure a port for port mirroring:
Highlight Mirroring from the Main Menu and press Enter.
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Figure 6-60. Mirroring Menu
To select the target port, highlight Target Port Selection and press Enter.
Figure 6-61. Target Port Selection screen
The target port is the port where information will be duplicated and sent for capture and network analysis. This is the port where a network analyzer would be attached to capture packets duplicated from the source port.
To select the source port(s) for mirroring, highlight Port Mirroring Settings and press Enter.
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Figure 6-62. Setup Port Mirroring screen
Up to 25 entries can be made to the port mirroring table, but it should be noted that a faster port (a
1000 Mbps Gigabit Ethernet port, for example) should not be mirrored to a slower port (one of the 24
100 Mbps Fast Ethernet port), because many packets will be dropped.
Parameter Description
Action:
<Add/Modify>
Source Port [24]
This field can be toggled between
Add/Modify and Delete using the space bar. Entries can be added, modified or deleted based upon the port number entered in the Source
Port field.
Allows the entry of the port number of the port to be mirrored. This port is the source of the packets to be duplicated and forwarded to the
Target port.
Direction:<Either> This field can be toggled between
Either, Ingress and Egress. Ingress mirrors only received packets, while
Egress mirrors only transmitted packets.
Priority
To configure a forwarding priority for a given MAC address, highlight Priority from the main menu and press Enter.
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Figure 6-63. Setup MAC Address Priority screen
The following fields can be set:
Parameter Description
Action:<Add/Modify> This field can be toggled between
Add/Modify and Delete using the space bar.
VID:[1 ] Allows the entry of the VLAN ID (VID) of the VLAN to which the MAC address below is a member of.
MAC Address:[ ] Allows the entry of the MAC address of the station for which priority queuing is to be specified.
Priority Level:<Low> This field can be toggled using the space bar between Low, Med-L
(Medium Low), Med-H (Medium
High), and High, corresponding to the priority of packets sent to or transmitted from the MAC address entered above.
Source/Destination:
<Src.>
This field can be toggled using the space bar between Src. (Source), Dst.
(Destination), and Either, corresponding to whether the MAC address entered above will be transmitting packets (a source), receiving packets (a destination) or both (either).
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Filtering
Layer 2 Filtering
To enter a MAC address into the filtering table, highlight Filtering from the Main Menu and press
Enter.
Figure 6-64. Filtering Menu
Highlight MAC Address Filter and press Enter.
Figure 6-65. Setup MAC Address Filter screen
When the switch is in Layer 2 Only operating mode, MAC addresses can be entered into the static filtering table. The switch can be configured to filter packets from this MAC address (a source), or to it
(a destination). The switch can also be configured to filter all packets to or from this MAC address
(either a source or a destination).
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The following fields can be set:
Parameter Description
Action:<Add/Modify
>
VID: [ ]
MAC Address:[ ]
This field can be toggled between
Add/Modify and Delete using the space bar.
Allows the entry of the VLAN ID (VID) of the VLAN to which the MAC address below is a member of.
Allows the entry of a MAC address to be filtered from the switch. This address must be a unicast MAC address.
Source/Destination:
<Scr.>
This field can be toggled using the space bar between Src. (Source), Dst.
(Destination), and Either, corresponding to whether the MAC address entered above will be transmitting packets (a source), receiving packets (a destination) or both (either).
Layer 3 (IP Routing) Filtering
With the switch configured to Layer 3 Operation mode, both MAC and IP addresses can be entered into the filtering table, using their respective entry menus. To enter an address, highlight Filtering from the
Main Menu and press Enter.
Figure 6-66. Filtering Menu – Layer 3
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Figure 6-67. Setup IP Address Filtering screen
The following fields can be set:
Parameter
Action:<Add/Modify
>
IP Address:[ ]
Source/Destination:
<Scr.>
Description
This field can be toggled between
Add/Modify and Delete using the space bar.
Allows the entry of an IP address to be filtered from the switch.
This field can be toggled between Src.
(source), Dst. (destination), and
Either. The IP address entered into the filtering table can be filtered as a source (packets will not be received from the IP address), as a destination
(packets will not be transmitted to the IP address), or as either a source or destination (packets will not be received from or transmitted to the IP address.
Forwarding
Layer 2 Forwarding
To enter a MAC address into the switch’s forwarding table highlight Forwarding from the Main Menu and press Enter.
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Figure 6-68. Forwarding Menu – Layer 2
Highlight MAC Address Forwarding from the Forwarding Menu and press Enter.
Figure 6-69. Setup Static Unicast MAC Forwarding screen
The following fields can be set:
Parameter Description
Action:<Add/Modify> The field can be toggled between
Add/Modify and Delete using the space bar.
VID:[ ] Allows the entry of the VLAN ID (VID) of the VLAN the MAC address below is a member of.
MAC Address:[ ]
Port: [ ]
Allows the entry of the MAC address of an end station that will be entered into the switch’s static forwarding table.
Allows the entry of the port number on which the MAC address entered
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IP Forwarding
Static/Default Routes
With the switch in Layer 3 Operation mode, entries into the switch’s forwarding table can be made using both MAC addresses and IP addresses. Static IP forwarding is accomplished by the entry of an IP address into the Static IP Routing table.
Static Address Resolution Protocol (ARP) entries can also be made from the Forwarding Menu.
Highlight Static/Default Routes from the Forwarding Menu and press Enter.
Figure 6-70. Setup Static IP Routes screen
The following fields can be set:
Parameter Description
Action:<Add > The field can be toggled between Add and Delete using the space bar.
IP Address:[ ] Allows the entry of an IP address that will be a static entry into the switch’s Routing table.
Subnet Mask:[ ] Allows the entry of a subnet mask corresponding to the IP address above.
Gateway IP:[ ] Allows the entry of an IP address of a gateway for the IP address above.
Metric:[1 ] Allows the entry of a routing protocol metric representing the number of routers between the switch and the
IP address above.
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Static ARP
To make a static ARP entry, highlight Static ARP from the Forwarding Menu and press Enter.
Figure 6-71. Setup Static ARP Entries screen
The following fields can be set:
Parameter Description
Action:
<Add/Modify>
The field can be toggled between
Add/Modify and Delete using the space bar.
Interface Name:[
]
The name of the IP interface the ARP entry resides on.
IP Address:[ ] The IP address of the ARP entry.
MAC Address:[ ] The MAC address of the ARP entry.
Spanning Tree
Switch Spanning Tree Settings
To globally configure STP on the switch highlight Spanning Tree on the Main Menu and press Enter.
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Figure 6-72. Configure Spanning Tree - Global
The Spanning Tree Protocol (STP) operates on two levels: on the switch level, the settings are globally implemented. On the port level, the settings are implemented on a per user-defined Group basis.
The factory default setting should cover the majority of installations. It is advisable to keep the default settings as set at the factory; unless, it is absolutely necessary to change them.
The following fields can be set:
Parameter Description
Status:<Enabled>
STP
Group:<Default>
Max. Age: [ ]
This field can be toggled between Enabled and Disabled using the space bar. This will enable or disable the Spanning Tree Protocol
(STP), globally, for the switch.
This field can be toggled using the space bar to select any of the STP groups that have been configured on the switch.
Hello Time:[ ] The Hello Time can be set from 1 to 10 seconds. This is the interval between two transmissions of BPDU packets sent by the Root Bridge to tell all other Switches that it is indeed the Root Bridge.
Forward Delay:[ ] The Forward Delay can be from 4 to 30 seconds. This is the time any port on the Switch spends in the listening state while moving from the blocking state to the forwarding state.
Priority:[ ]
The Max. Age can be set from 6 to 40 seconds. At the end of the Max.
Age, if a BPDU has still not been received from the Root Bridge, your
Switch will start sending its own BPDU to all other Switches for permission to become the Root Bridge. If it turns out that your Switch has the lowest Bridge Identifier, it will become the Root Bridge.
A Priority for the switch can be set from 0 to 65535. This number is used in the voting process between switches on the network to determine which switch will be the root switch. A low number indicates a high priority, and a high probability that this switch will be elected as the root switch.
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The Hello Time cannot be longer than the Max. Age. Otherwise, a configuration error will occur.
Observe the following formulas when setting the above parameters:
Max. Age ≤ 2 x (Forward Delay - 1 second)
Max. Age ≥ 2 x (Hello Time + 1 second)
STP Group Configuration
To define which ports will be members of an STP Group, highlight Group Create/Delete and press
Enter.
Figure 6-73. STP Group Configuration screen
Toggle the Action field to Add/Modify. Choose a name for the group and enter it in the Group Name field. The group name does not necessarily have to correspond to any name that has been previously entered in the switch’s configuration.
Figure 6-74. Port Spanning Tree Settings screen
Toggle the View Ports field to the range of ports to be configured. The Fast Ethernet ports displayed for configuration in groups of 12 and the two (optional) Gigabit Ethernet ports are displayed together.
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In addition to setting Spanning Tree parameters for use on the switch level, the DES-3326 allows for the configuration of groups of ports, each port-group of which will have its own spanning tree, and will require some of its own configuration settings. An STP Group will use the switch-level parameters entered above, with the addition of Port Priority and Port Cost.
An STP Group spanning tree works in the same way as the switch-level spanning tree, but the root bridge concept is replaced with a root port concept. A root port is a port of the group that is elected on the basis of port priority and port cost, to be the connection to the network for the group. Redundant links will be blocked, just as redundant links are blocked on the switch level.
The STP on the switch level blocks redundant links between switches (and similar network devices).
The port level STP will block redundant links within an STP Group.
It is advisable to define an STP Group to correspond to a VLAN group of ports.
The following fields can be set:
Parameter Description
View Ports:< > This field can be toggled using the space bar between 1 to 12, 13 to 24, and 25-26. This is used to select the range of ports displayed in the console.
Configure Ports:[
] to [ ]
Allows the entry of a range of port numbers to be configured.
Port Cost:[ ] A Port Cost can be set from 1 to
65535. The lower the number, the greater the probability the port will be chosen to forward packets.
Priority:[ ] A Port Priority can be from 0 to 255.
The lower the number, the greater the probability the port will be chosen as the Root Port.
Link Aggregation
To configure a link aggregation group, highlight Link Aggregation on the Main Menu and press Enter.
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Figure 6-75. Link Aggregation screen
Link aggregation allows several ports to be grouped together and to act as a single link. This gives a bandwidth that is a multiple of a single link’s bandwidth.
Link aggregation is most commonly used to link a bandwidth intensive network device or devices – such as a server – to the backbone of a network.
The DES-3326 allows the creation of up to 6 link aggregation groups, each group consisting of up of up to 8 links (ports). The aggregated links must be contiguous (they must have sequential port numbers) except the two (optional) Gigabit ports – which can only belong to a single link aggregation group. A link aggregation group may not cross an 8-port boundary, starting with port 1 (a group may not contain ports 8 and 9, for example) and all of the ports in the group must be members of the same VLAN.
Further, the aggregated links must all be of the same speed and should be configured as full duplex.
The configuration of the lowest numbered port in the group becomes the configuration for all of the ports in the aggregation group. This port is called the Master Port of the group, and all configuration options – including the VLAN configuration – that can be applied to the Master Port are applied to the entire link aggregation group.
Load balancing is automatically applied to the ports in the aggregated group, and a link failure within the group causes the network traffic to be directed to the remaining links in the group.
The Spanning Tree Protocol will treat a link aggregation group as a single link, on the switch level. On the port level, the STP will use the port parameters of the Master Port in the calculation of port cost and in determining the state of the link aggregation group. If two redundant link aggregation groups are configured on the switch, STP will block one entire group – in the same way STP will block a single port that has a redundant link.
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The following fields can be set:
Parameter Description
Group ID:[1] This field can be toggled between any one of the six possible link aggregation groups configurable on the switch.
The Master port of link aggregation group. Port:[1]
Group Width:[ ] Allows the entry of the number of contiguous ports that will make up the link aggregation group. These ports will be in sequential order from the Master Port.
Method:
<Disabled>
This field can be toggled between Enabled and Disabled.
This is used to turn a link aggregation group on or off. This is useful for diagnostics, to quickly isolate a bandwidth intensive network device or to have an absolute backup link aggregation group that is not under automatic control.
Spanning Tree
The Spanning Tree Protocol can be used to detect and disable network loops, and to provide backup links between switches, bridges, or routers. This allows the switch to interact with other bridging devices (that is, STP compliant switches, bridges, or routers) in your network to ensure that only one route exists between any two stations on the network.
The following figures and tables describe the configuration of the Spanning Tree Protocol (STP) on the switch.
Configure Spanning Tree
To configure the spanning tree protocol on the switch, highlight Spanning Tree from the Main Menu and press Enter.
Figure 6-76. Configure Spanning Tree menu
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The following fields can be set:
Parameter Default Description
Status:<Enabled> Enabled Allows the STP to be globally Enabled or Disabled on the switch.
Max Age
Hello Time
Forward Delay
20
2
15
The maximum time (in seconds) a device can wait without receiving a configuration message before attempting to reconfigure. All device ports (except for designated ports) should receive configuration messages at regular intervals.
Any port that ages out STP information (provided in the last configuration message) becomes the designated port for the attached LAN. If it is a root port, a new root port is selected from among the device ports attached to the network.
The minimum value is the higher of 6 or [2 x (Hello
Time +1)].
The maximum value is the lower of 40 or [2 x
(Forward Delay –1)].
The time interval (in seconds) at which the root device transmits a configuration message.
The maximum time (in seconds) the root device will wait before changing states (i.e., from the listening to learning to forwarding). This delay is required because every device must receive information about topology changes before it starts to forward packets. In addition, each port needs time to listen for conflicting information that would make it return to a blocking state; otherwise, temporary data loops might result.
Maximum value is 30
Minimum value is the higher of 4 or [(Max. Age / 2) +1]
Priority 32,768 Device priority used in selecting the root device, root port, and designated port. The device with the highest priority becomes the STP root device. The lower the numeric value, the higher the priority. If all devices have the same priority, the device with the lowest MAC address will become the root device.
STP Group
Range 0 to 65535.
Default Allows the selection of one of the STP Groups previously configured on the switch
:<Default>
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Create Spanning Tree Groups
The DES-3326 switch allows you to configure Spanning Tree Groups that consist of a group of ports that will be handled as though they were a single spanning tree device. The following figures and tables describe how to configure a spanning tree group.
To configure spanning tree groups on the switch, highlight STP Group Configuration from the Main
Menu and press Enter.
Figure 6-77. STP Group Configuration screen
The following fields can be set:
Parameter
Action:
<Add/Modify>
Group Name:
[ ]
Membership
(M/-):[ ][ ][ ]
Description
The field can be toggled between
Add/Modify and Delete using the space bar.
A 12-character name used to identify a given STP group.
Allows the selected port to be designated as a member of the current
STP Group. Move the blinking cursor below the dash representing the port to be made a member and toggle between
− and M. − signifies that the selected port is not a member of the STP Group, and M signifies that the port is a member of the STP Group.
Spanning Tree Port Settings
The following figure and table describe the display of the current STP port settings on the switch.
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Figure 6-78. Port Spanning Tree Settings screen
The following fields can be set:
Parameter Description
View Ports:
<1 to 12>
Allows the selection of groups of ports to view. Can be toggled between 1 to 12,
13 to 24, and Slot-1.
Configure Port
from [1 ] to [1 ]
Allows the selection of range of port numbers to be configured.
Port Cost:[19 ]
Priority:[128]
A port cost can be set between 1 and
65535. The lower the cost, the greater the probability the port will be chosen as the designated port (chosen to forward packets).
A port priority can be set between 0 and 255. The lower the priority, the greater the probability the port will be chosen as the root port.
Utilities
Layer 2 Switch Utilities
To access the Switch Utilities menu, highlight Utilities from the Main Menu and press Enter.
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Figure 6-79. Switch Utilities menu
Trivial File Transfer Protocol (TFTP) services allow the switch firmware to be upgraded by transferring a new firmware file from a TFTP server to the switch. A configuration file can also be loaded into the switch from a TFTP server, switch settings can be saved to the TFTP server, and a history log can be uploaded from the switch to the TFTP server.
Upgrade Firmware from TFTP Server
To update the switch’s firmware, highlight Upgrade Firmware from TFTP Server and press Enter.
Figure 6-80. Upgrade Firmware screen
Enter the IP address of the TFTP server in the Server IP Address field.
The TFTP server must be on the same IP interface as the switch.
Enter the path and the filename to the firmware file on the TFTP server. Note that in the above example, the firmware file is in the root directory of the C drive of the TFTP server.
The TFTP server must be running TFTP server software to perform the file transfer. TFTP server software is a part of many network management software packages – such as NetSight, or can be obtained as a separate program.
Highlight APPLY and press Enter to record the IP address of the TFTP server. Use Save Changes from the Main Menu to enter the address into NV-RAM
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Highlight START and press Enter to initiate the file transfer.
Use Configuration File on TFTP Server
To download a switch configuration file from a TFTP server, select Use Configuration File on TFTP
Server and press Enter.
Figure 6-81. Use Configuration File on TFTP Server screen
Enter the IP address of the TFTP server and specify the location of the switch configuration file on the
TFTP server.
Highlight APPLY and press Enter record the IP address of the TFTP server. Use Save Changes from the
Main Menu to enter the address into NV-RAM
Highlight START and press Enter to initiate the file transfer.
Save Settings to TFTP Server
To upload a settings file to the TFTP server, highlight Save Settings to TFTP Server and press Enter.
Figure 6-82. Save Settings to TFTP Server screen
Enter the IP address of the TFTP server and the path and filename of the settings file on the TFTP server and press APPLY. Highlight START and press Enter to initiate the file transfer.
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Save History Log to TFTP Server
To save a History Log on a TFTP server, highlight Save History Log to TFTP Server and press Enter.
Figure 6-83. Save Log to TFTP Server screen
Enter the IP address of the TFTP server and the path and filename for the history log on the TFTP server. Highlight APPLY and press Enter to make the changes current. Highlight START and press
Enter to initiate the file transfer.
Testing Connectivity with Ping
To test the connection with another network device using Ping, highlight Ping Test and press Enter.
Figure 6-84. Ping screen
Enter the IP address of the network device to be pinged and the number of test packets to be sent (3 is usually enough). Highlight START and press Enter to initiate the ping program.
Layer 3 Utilities
Layer 3 (IP Routing) switch operation mode adds BOOTP Relay and DNS Relay to the utilities available on the switch.
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BOOTP/DHCP Relay
To enter the IP addresses of BOOTP or DHCP servers (for the BOOTP/DHCP Relay service):
Highlight Utilities on the Main Menu and press Enter. Next, highlight BOOTP/DHCP Relay on the
Switch Utilities menu and press Enter.
Figure 6-85. BOOTP/DHCP Relay menu
The following fields can be set:
Parameter Description
BOOTP/DHCP
Relay Status
<Disabled>
This field can be toggled between
Enabled and Disabled using the space bar. It is used to enable or disable the BOOTP/DHCP Relay service on the switch. The default is
Disabled.
Count Limit [4 ]
This field allows an entry between 1 and 16 to define the maximum number of router hops BOOTP messages can be forwarded across.
The default hop count is 4.
BOOTP/DHCP
Relay Time
Threshold:[0 ]
Allows an entry between 0 and
65535 seconds, and defines the maximum time limit for routing a
BOOTP/DHCP packet. If a value of 0 is entered, the switch will not process the value in the seconds field of the BOOTP or DHCP packet. If a non-zero value is entered, the switch will use that value, along with the hop count to determine whether to forward a given BOOTP or DHCP packet.
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To configure the BOOTP/DHCP Relay interface, highlight BOOTP/DHCP Relay Interface
Configuration from the BOOTP/DHCP Relay menu and press Enter.
Figure 6-86. BOOTP/DHCP Relay Interface Configuration screen
The following fields can be set:
Parameter Description
Action:<Add> This field can be toggled between
Add and Delete using the space bar.
Toggle to Add and enter the subnet name for which BOOTP Relay will be active.
Interface Name:[
]
The interface name of the IP interface on which the BOOTP or DHCP servers reside.
IP Address:
BOOTP/DHCP
Server:[ ]
Displays the IP address corresponding to the subnet name entered above.
Allows the entry of IP addresses for up to four BOOTP or DHCP servers.
DNS Relay
To enter the IP addresses of DNS servers (for the DNS Relay service):
Highlight DNS Relay on the Switch Utilities menu and press Enter.
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Figure 6-87. DNS Relay screen
The following fields can be set:
Parameter Description
DNSR Status
<Disabled>
This field can be toggled between
Disabled and Enabled using the space bar, and is used to enable or disable the DNS Relay service on the switch.
Name Server:[1][2] Allows the entry of the IP address of a primary (number 1) and a secondary (number 2) domain name server (DNS).
DNSR Cache
Status:<Disabled>
This can be toggled between Disabled and Enabled. This determines if a
DNS cache will be enabled on the switch.
DNSR Static Table
Lookup
Status:<Disabled>
This field can be toggled using the space bar between Disabled and
Enabled. This determines if the static
DNS table will be used or not.
To make a static DNS table entry:
Select Static table configuration on the DNS Relay menu and press Enter.
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Figure 6-88. DNS Relay – Static table configuration screen
The following fields can be set:
Parameter Description
Action:<Add/Edit> The Action field can be toggled between Add/Edit and Delete. Enter the Domain name and its corresponding IP address.
Domain Name
IP Address
The domain name of the static DNS table entry.
The IP address of the domain name above.
Status:<Enabled> This field can be toggled using the space bar between Enabled and
Disabled.
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Network Monitoring
The DES-3326 provides extensive network monitoring capabilities that can be viewed under Network
Monitoring Menu from the Main Menu.
Network monitoring on the switch is divided into Layer 2 and Layer 3 functions, depending upon which operating mode the switch is in. Layer 2 network monitoring functions are visible on the console when the switch is in Layer 2 Only operating mode. Layer 3 network monitoring functions are added to the console when the switch is in IP Routing operating mode.
Layer 2 Network Monitoring
Layer 2 network monitoring consists of the following screens or menus:
• Port Utilization
• Port Error Packets
• Port Packet Analysis
• Browse MAC Address (view the MAC address forwarding table)
• GVRP (view the GVRP status table)
• GMRP (view the GMRP status table)
• Browse Router Port (view the router port status table)
• IGMP Snooping
• Switch History
To display the network data compiled by the switch:
Highlight Network Monitoring on the Main Menu and press Enter.
Figure 6-89. Network Monitoring Menu
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Port Utilization
The Port Utilization screen shows the number of packets transmitted and received per second and calculates the percentage of the total available bandwidth being used on the port (displayed under
%Util.).
To view the port utilization:
Highlight Port Utilization on the Network Monitoring Menu and press Enter.
TX/sec
RX/sec
%Util
Figure 6-90. Port Utilization screen
Parameter
Port
Interval:<2 sec>
Description
The switch’s port number.
The time between updates received from the switch. Suspend stops the updates. The default is 2 seconds.
The rate at which the given port is transmitting packets, in packets per second.
The rate at which the given port is receiving packets, in packets per second.
The percentage utilization of the given port’s available bandwidth.
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Port Error Packets
The Packet Error Statistic screen displays the packet errors that the switch can detect and displays the results on a per port basis.
To view the error statistics for a port:
Highlight Port Error Packets on the Network Monitoring Menu and press Enter.
Figure 6-91. Packet Error Statistic screen
The Port field can be toggled between Port 1~26 to select which group of ports will be displayed.
Enter the port number of the port to be viewed. The Interval field can be toggled from 2 seconds to 1 minute, or suspend. This sets the interval at which the error statistics are updated.
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RX Frames
CRC Error
Undersize
Oversize
Fragments
Jabber
Drop Pkts
TX Frames
ExDefer
CRC Error
Late Coll.
Ex. Coll.
Single Coll.*
Coll.
Parameter
Interval:<2 sec>
Description
The interval (in seconds) that the table is updated. The default is 2 seconds.
Received packets.
For 10 Mbps ports, the counter records CRC errors (FCS or alignment errors). For 100 Mbps ports, the counter records the sum of CRC errors and code errors (frames received with rxerror signal).
The total number of frames received that were less than 64 octets long
(excluding framing bits, but including FCS octets) and were otherwise well formed.
The total number of frames received that were longer than 1518 octets
(excluding framing bits, but including FCS octets) and were otherwise well formed.
The total number of frames received that were less that 64 octets in length (excluding framing bits, but including FCS octets) and had either an FCS or an alignment error.
The total number of frames received that were longer than 1518 octets
(excluding framing bits, but including FCS octets), and had either an
FCS or an alignment error.
The total number of events in which packets were dropped due to a lack of resources.
Transmitted packets.
The number of frames for which the first transmission attempt on a particular interface was delayed because the medium was busy
For 10 Mbps ports, the counter records CRC errors (FCS or alignment errors). For 100 Mbps ports, the counter records the sum of CRC errors and code errors (frames received with rxerror signal).
Late Collisions. The number of times that a collision is detected later than 512 bit-times into the transmission of a packet.
Excessive Collisions. The number of frames for which transmission failed due to excessive collisions.
Single Collision Frames. The number of successfully transmitted frames for which transmission is inhibited by more than one collision.
An estimate of the total number of collisions on this network segment.
Port Packet Analysis
The Packet Analysis screen displays the size of packets received or transmitted by a given switch port.
In addition, statistics on the number and rate of unicast, multicast, and broadcast packets received by the switch are displayed.
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To view an analysis of packets received or transmitted by a port:
Highlight Port Packet Analysis on the Network Monitoring Menu and press Enter.
Figure 6-92. Packet Analysis screen
Interval:<2 sec>
Frames
Frames/sec
Unicast RX
Multicast RX
Broadcast RX
RX Bytes
RX Frames
TX Bytes
Parameter
TX Frames
Description
The interval (in seconds) that the table is updated. The default is 2 seconds.
The number of packets (or frames) received or transmitted by the switch with the size, in octets, given by the column on the right.
The number of packets (or frames) transmitted or received, per second, by the switch.
Displays the number of unicast packets received by the switch in total number (Frames) and the rate (Frames/sec).
Displays the number of multicast packets received by the switch in total number (Frames) and the rate (Frames/sec).
Displays the number of broadcast packets received by the switch in total number (Frames) and the rate (Frames/sec).
Displays the number of bytes (octets) received by the switch in total number (Total), and rate (Total/sec).
Displays the number of packets (frames) received by the switch in total number (Total), and rate (Total/sec).
Displays the number of bytes (octets) transmitted by the switch in total number (Total), and rate (Total/sec).
Displays the number of packets (frames) transmitted by the switch in total number (Total), and rate (Total/sec).
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Browse MAC Address
This allows the switch’s dynamic MAC address forwarding table to be viewed. When the switch learns an association between a MAC address and a port number, it makes an entry into its forwarding table.
These entries are then used to forward packets through the switch.
To view the MAC address forwarding table:
Highlight Browse MAC Address on the Network Monitoring Menu and press Enter.
Figure 6-93. Browse Address Table screen
The Browse By field can be toggled among ALL, MAC Address, Port, and VLAN. This sets a filter to determine which MAC addresses from the forwarding table are displayed. ALL specifies no filter.
To search for a particular MAC address:
Toggle the Browse By field to MAC Address. A MAC Address field will appear. Enter the MAC address in the field and press Enter.
GVRP
This allows the GVRP status for each of the switch’s ports to be viewed by VLAN. The GVRP status screen displays the ports on the switch that are currently Egress or Untagged ports.
To view the GVRP status table:
Highlight GVRP from the Network Monitoring Menu and press Enter.
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Figure 6-94. GVRP Status screen
GMRP
The Group Multicast Registration Protocol (GMRP) Status screen displays the status of ports that have
GMRP enabled on the switch.
To view the GMRP Status table:
Highlight GMRP from the Network Monitoring Menu and press Enter.
Figure 6-95. GMRP Status screen
Browse Router Port
This displays which of the switch’s ports are currently configured as router ports. A router port configured by a user (using the console or Web-based management interfaces) is displayed as a static router port, designated by S. A router port that is dynamically configured by the switch is designated by
D.
To view the Router Port table:
Highlight Browse Router Port from the Network Monitoring Menu and press Enter.
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Figure 6-96. Browse Router Port screen
The Jump to VID field allows the entry of any VLAN ID (VID) of any VLAN defined on the switch. Enter the VID, highlight GO and press Enter. The table will then jump to the VID entered.
S signifies a static router port, configured by the user.
D signifies a dynamically assigned router port, configured by the switch.
IGMP Snooping
This allows the switch’s IGMP Snooping table to be viewed. IGMP Snooping allows the switch to read the Multicast Group IP address and the corresponding MAC address from IGMP packets that pass through the switch. The ports where the IGMP packets were snooped are displayed, signified with an M.
The number of IGMP reports that were snooped are also displayed in the Reports field.
To view the IGMP Snooping table:
Highlight IGMP Snooping Status from the Network Monitoring Menu and press Enter.
Figure 6-97. IGMP Snooping Status screen
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Switch History
This allows the Switch History Log to be viewed. The switch records all traps, in sequence, that identify events on the switch. The time since the last cold start of the switch is also recorded.
To view the switch history log:
Highlight Switch History from the Network Monitoring Menu and press Enter.
Figure 6-98. Switch History screen
Layer 3 Network Monitoring
When the switch is in Layer 3 (IP Routing) mode, several items are added to the Network Monitoring
Menu.
The following items are added to the Network Monitoring Menu when the switch is in Layer 3
(IP Routing) mode:
• Browse IP Address
• Routing Table
• ARP Table
• Default IP Table
• OSPF LSDB Table
• OSPF External LSDB Table
• IP Multicast Forwarding Table
• IGMP Group Table
• DVMRP Routing Table
To view the Network Monitoring Menu:
Highlight Network Monitoring from the Main Menu and press Enter.
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Figure 6-99. Network Monitoring Menu – Layer 3
Browse IP Address
To view the IP address forwarding table:
Highlight Browse IP Address from the Network Monitoring Menu and press Enter.
Figure 6-100. Browse IP Address Table – Layer 3
To display a particular IP address, enter the IP address in the Jump to IP Address field, highlight GO, and press Enter.
Routing Table
To view the contents of the IP Routing table:
Highlight Routing Table on the Network Monitoring Menu and press Enter.
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Figure 6-101. Browse Routing Table screen
To display a particular Destination IP address, enter either the IP address in the Jump to Destination
Address field, the gateway address in the Gateway field and the subnet mask in the Mask field, highlight GO, and press Enter.
The following fields are displayed:
Parameter Description
Destination
Address
Mask
Gateway
Go
Interface
Hops
Protocol
IP address of a learned or statically entered destination.
Displays the subnet mask corresponding to the above destination IP address.
Displays the default or next hop gateway to reach the destination.
Click the Go button to go to a particular combination of destination
IP address, subnet mask, and gateway address.
Displays the IP interface name the destination resides on.
Displays the number of hops
(routers) between the switch and the destination.
Displays the routing protocol in use by the link to the destination.
ARP Table
To view the ARP table:
Highlight ARP Table on the Network Monitoring Menu and press Enter.
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Figure 6-102. Browse ARP Table screen
To display a particular IP interface or an IP address, enter either the IP interface name in the Jump to
Interface Name field or enter the IP address in the IP Address field, highlight GO, and press Enter.
Default IP Table
The Default IP Address Table displays the static IP addresses.
To view the Default IP Address Table:
Highlight Default IP Table from the Network Monitoring Menu and press Enter.
Figure 6-103. Default IP Address screen
OSPF LSDB Table
The Monitor Link-State Database Table displays the current link-state database in use by the OSPF routing protocol on a per-OSPF area basis.
To view the Monitor LSDB Table:
Highlight OSPF LSDB Table from the Network Monitoring Menu and press Enter.
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Figure 6-104. Monitor LSDB Table screen
The following fields are displayed:
Parameter Description
Area ID Allows the entry of an OSPF Area ID. This Area ID will then be used to search the table, and display an entry − if there is one.
LSDB Type Displays which one of four types of link advertisements by which the current link was discovered by the switch: Router link (RTRLink),
Network link (NETLink), Summary link (Summary), Autonomous
System link (ASSummary).
Adv Router
ID
Displays the Advertising Router’s ID.
Link State
ID
This field identifies the portion of the internet environment that is being described by the advertisement. The contents of this field depend on the advertisement's LS type.
LS Type Link State ID
____________________________________________
1 The originating router's Router ID.
2 The IP interface address of the network's Designated Router.
3 The destination network's IP address.
Mask
4 The Router ID of the described AS boundary router.
Displays the network mask in hexadecimal format. For example,
255.0.0.0 is displayed as FF000000.
Displays the routing metric associated with the link. Cost
Sequence Displays a sequence number corresponding to number of times the current link has been advertised as changed.
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OSPF External LSDB Table
The external OSPF Link State Database (LSDB) table can be viewed by highlighting OSPF External
LSDB Table and pressing Enter.
Figure 6-105. Monitor External LSDB Table screen
The following fields are displayed:
Parameter Description
Advertise
Router ID
Allows the entry of a Router ID. This is then used to search the External LSDB Table and display the results − if any.
Adv Router
ID
Displays the Advertising Router’s ID.
Link State
ID
This field identifies the portion of the internet environment that is being described by the advertisement. The contents of this field depend on the advertisement's LS type.
LS Type Link State ID
__________________________________________
5 The destination network’s IP address.
Mask
Cost
Displays the network mask in hexadecimal format. For example, 255.0.0.0 is displayed as FF000000.
Displays the routing metric associated with the link.
Sequence Displays a sequence number corresponding to number of times the current link has been advertised as changed.
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IP Multicast Forwarding Table
To view the IP multicast forwarding table:
Highlight IP Multicast Forwarding Table from the Network Monitoring Menu and press Enter.
Figure 6-106. Browse IP Multicast Forwarding Table screen
To display a particular multicast group, enter either the IP address in the Jump to Multicast Group field, enter the source IP address in the Source IP field, or the source subnet mask in the Source Mask field, highlight GO, and press Enter.
This sets a filter to determine which IP addresses and multicast groups from the table are displayed.
To display a particular source IP address, enter either the IP address in the Jump to IP Address field and the source subnet mask in the Source Mask field, highlight GO, and press Enter.
IGMP Group Table
To view the IGMP Group table:
Highlight IGMP Group Table from the Network Monitoring Menu and press Enter.
Figure 6-107. Browse IGMP Group Table screen
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To display a particular multicast group, enter either the IP address in the Jump to Interface Name field, enter the multicast group IP address in the Multicast Group field, highlight GO, and press Enter.
DVMRP Routing Table
To view the DVMRP Routing table:
Highlight DVMRP Routing Table from the Network Monitoring Menu and press Enter.
Figure 6-108. Browse DVMRP Routing Table screen
The Jump to Source IP Address and Source Mask fields allow the entry of an IP address and corresponding subnet mask to search the table for. Highlight GO and press Enter and the DVMRP
Routing table will be searched for the IP address and subnet mask above.
Load Factory Defaults
To reset the switch to all factory defaults:
Highlight Reboot on the Main Menu and press Enter.
Figure 6-109. System Reboot menu
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Highlight one of the two Load Factory Default Configuration entries and press Enter. A confirmation screen will appear. Press Y for Yes and press Enter.
The factory defaults for the DES-3326 are listed in Appendix D of this manual.
Reboot
The DES-3326 has several reboot options.
To reboot the switch from the console:
Highlight Reboot from the Main Menu and press Enter.
Figure 6-110. System Reboot menu
The reboot options are as follows:
Reboot simply restarts the switch. Any configuration settings not saved using Save Changes from the
Main Menu will be lost. The switch’s configuration will be restored to the last configuration saved in
NV-RAM.
Save Configuration & Reboot saves the configuration to NV-RAM (identical to using Save Changes) and then restarts the switch.
Reboot & Load Factory Default Configuration restarts the switch using the default factory configuration. All configuration data will be lost.
Reboot & Load Factory Default Configuration Except IP Address restarts the switch using the default factory configuration, except the user configured IP address will be retained. All other configuration data will be lost.
A confirmation screen will appear:
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Figure 6-111. System Reboot Confirmation screen
To reboot the switch, in the mode entered above, highlight Yes and press Enter.
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7
W
EB
-B
ASED
N
ETWORK
M
ANAGEMENT
Introduction
The DES-3326 offers an embedded Web-based (HTML) interface allowing users to manage the switch from anywhere on the network through a standard browser such as Netscape Navigator/Communicator or Microsoft Internet Explorer. The Web browser acts as a universal access tool and can communicate directly with the Switch using the HTTP protocol.
The Web-based management module and the Console program (and Telnet) are different ways to access the same internal switching software and configure it. Thus, all settings encountered in web-based management are the same as those found in the console program.
Note: This Web-based Management Module does not accept Chinese language input (or other languages requiring 2 bytes per character).
Where there is a difference in the setup of the switch between its two operational modes (Layer 2 Only and IP Routing), the sections are divided to correspond with the switch operating mode that is applicable.
Note: IP Routing mode switch configuration settings that are saved NV-RAM using Save
Changes from the Main Menu are retained in the switch’s memory when the operational
mode is changed. IP Routing mode settings are simply inactive when the switch is in
Layer 2 Only mode.
Before You Start
The DES-3326 Layer 3 Switch supports a wide array of functions and gives great flexibility and increased network performance by eliminating the routing bottleneck between the WAN or Internet and the Intranet. Its function in a network can be thought of as a new generation of router that performs routing functions in hardware, rather than software.
This flexibility and rich feature set requires a bit of thought to arrive at a deployment strategy that will maximize the potential of the DES-3326 Layer 3 switch.
General Deployment Strategy
1. Determine how the network would be best segmented. This is probably done using VLANs in an existing layer 2 switched network.
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2. Develop an IP addressing scheme. This involves allocating a block of IP addresses to each network segment. Each network interface is then assigned a network address and a subnet mask. See Chapter 5, Switch Management Concepts section titled IP Addressing and
Subnetting for more information.
3. Determine which network resources must be shared by the interfaces. Shared resources may be connected directly to the Layer 3 switch, if need be. Static routes to each of the shared resources should be determined.
4. Determine how each interface will communicate with the WAN or Internet. Again, static routes should be determined and default gateways identified.
5. Develop a security scheme. Some interfaces on the network need more security or should be isolated from the other interfaces. IP or MAC filtering can be used. Also, one or more VLANs on the Layer 3 switch can be configured without an IP interface – in which case, these VLANs will function as a layer 2 VLAN and would require an external router to connect to the rest of the network.
6. Develop a policy scheme. Some interfaces will have a greater need for multicasting bandwidth, for example. A policy is a mechanism to alter the normal packet forwarding in a network device, and can be used to intelligently allocate bandwidth to time-critical applications such as the integration of voice, video, and data on the network.
7. Develop a redundancy scheme. Planning redundant links and routes to network critical resources can save valuable time in case of a link or device failure. The DES-3326 Spanning
Tree function can be used to block the redundant link until it is needed.
VLAN Layout
VLANs on the DES-3326 have rather more functions than on a traditional layer 2 switch, and must therefore be laid-out and configured with a bit more care. Layer 3 VLANs (VLANs with an IP interface assigned to them) could be thought of as network links – not just as a collection of associated end users. Further, Layer 3 VLANs are assigned an IP network address and subnet mask to enable IP routing between them.
Layer 3 VLANs must be configured on the switch before they can be assigned IP interfaces. Further, the static VLAN configuration is specified on a per port basis. On the DES-3326, a VLAN can consist of end-nodes – just like a traditional layer 2 switch, but a VLAN can also consist of one or more layer 2 switches – each of which is connected to multiple end-nodes or network resources.
So, a Layer 3 VLAN, consisting of 4 ports, could be connected to 4 layer 2 switches. If these layer 2 switches each have 24 ports, then the Layer 3 VLAN would contain 4 x 24 = 96 end nodes. Assigning an
IP interface to the Layer 3 VLAN would allow wire-speed IP routing from the WAN to each end node and between end nodes.
So, the IP interfaces for a network must be determined first, and the VLANs configured on the switch to accommodate the IP interfaces. Finally, the IP interfaces can be assigned to the VLANs.
Assigning IP Network Addresses and Subnet Masks to VLANs
The DES-3326 allows the assignment of IP interfaces to individual VLANs. Any VLAN configured on the switch that is not assigned an IP interface, will behave as a layer 2 VLAN and will not be capable of IP routing – even if the switch is in IP Routing mode.
Developing an IP addressing scheme is a complex subject, but it is sufficient here to mention that the total number of anticipated end nodes – for each Layer 3 VLAN – must be accommodated with a unique
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IP address. It should be noted that the switch regards a VLAN with an IP network address and corresponding subnet mask assigned as an IP interface in IP Routing mode.
Defining Static Routes
Routes between the IP interfaces and a default gateway or other router with a WAN connection should be determined beforehand and entered into the static/default routing table on the DES-3326.
Getting Started
The first step in getting started in using web-based management for your Switch is to secure a browser.
A Web browser is a program that allows a person to read hypertext, for example, Opera, Netscape
Navigator, or Microsoft Internet Explorer. Follow the installation instructions for the browser.
The second and last step is to configure the IP interface of the Switch. This can be done manually through a console (see the Configure IP Address section in Chapter 6, “Using The Console Interface”).
Management
To begin managing your Switch simply run the browser you have installed on your computer and point it to the IP address you have defined for the device. The URL in the address bar should read something like: http://123.123.123.123, where the numbers 123 represent the IP address of the switch.
Note: The Factory default IP address for the switch is 10.90.90.90.
In the page that opens, click on the Login to DES-3326 Manager button:
Figure 7-1. Login button
This opens the main page in the management module.
The switch management features available in the Web-based are explained below.
Configuring the Switch
User Accounts Management
From the main menu, click Management and then select User Accounts Management.
Figure 7-2. User Accounts Control Table window
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Click New to add a user.
Figure 7-3. User Accounts Control Table – Add window
1. Enter the new user name, assign an initial password, and then confirm the new password.
Determine whether the new user should have Root, User+, or User privileges.
2. Click Apply to make the user addition effective.
3. A listing of all user accounts and access levels is shown on the user accounts control table. This list is updated when Apply is executed.
4. Please remember that Apply makes changes to the switch configuration for the current session
only. All changes (including User additions or updates) must be entered into non-volatile RAM using the Save Changes window on the Maintenance menu - if you want these changes to be permanent.
Root, User+ and Normal User Privileges
There are three levels of user privileges: Root and User+, and User. Some menu selections available to users with Root privileges may not be available to those with User+ and User privileges.
The following table summarizes the Root, User+ and User privileges:
Switch Configuration Privilege
Management Root User+
Configuration Yes Read Only
Network Monitoring
Community Strings and Trap
Stations
Yes
Yes
Read Only
Read Only
Update Firmware and Configuration
Files
System Utilities
Reboot and Load Factory Defaults
Reboot Switch
Yes No
Yes
Yes
Yes
Ping Only
No
Yes
User Accounts Management
User
Read Only
Read Only
Read Only
No
Ping Only
No
No
Add/Update/Delete User Accounts
View User Accounts
Yes
Yes
No
No
No
No
Table 7-1. Root, User+, and User Privileges
After establishing a User Account with Root-level privileges, click Save Changes on the Maintenance menu and then click Save Configuration (see below). The switch will save any changes to its nonvolatile ram and reboot. You can logon again and are now ready to continue configuring the switch.
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Saving Changes
The DES-3326 has two levels of memory; normal RAM and non-volatile or NV-RAM. Configuration changes are made effective by clickng Apply. When this is done, the settings will be immediately applied to the switching software in RAM, and will immediately take effect.
Some settings, though, require you to restart the switch before they will take effect. Restarting the switch erases all settings in RAM and reloads the stored settings from the NV-RAM. Thus, it is necessary to save all setting changes to NV-RAM before rebooting the switch.
To retain any configuration changes permanently, click Save Changes on the Maintenance menu and then click Save Configuration on the following window:
Figure 7-4. Save Changes window
Once the switch configuration settings have been saved to NV-RAM, they become the default settings for the switch. These settings will be used every time the switch is rebooted.
Reboot and Load Factory Defaults
The following window is used to restart the switch using only the configuration that was supplied by the factory. To return all configuration options to their default values and restores the switch’s configuration to the factory settings, select Factory Reset on the Maintenance menu.
Please note that all user-entered configuration information will be lost.
Figure 7-5. Factory Reset to Default Value window
Check Yes if you want the switch to retain its current IP address. Check No to reset the switch’s IP address to the factory default, 10.90.90.90.
Click the Reset to Factory Default button to restart the switch.
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USING WEB-BASED MANAGEMENT
Setting Up Web Management
Before running Web-based management, some basic configuration of the switch may need to be performed. The following at a minimum must be configured or known for the switch to be managed:
• IP Address
• Administrator password
In addition, several other parameters may need to be configured or known to properly communicate with the switch or allow full management capability. These include:
• Default Gateway
• Trap Destination and Community Name
Configuration of these items may be made from the User Interface, which is accessible via either the serial console or Telnet. Refer to the User’s Guide that came with your system for more information describing the required configuration.
Setting an IP Address
The IP address for the switch must be set before it can be managed with the Web-based manager. The switch IP address may be automatically set using BOOTP protocol, in which case the actual address assigned to the switch must be known.
The IP address may alternatively be set manually as follows:
1. Starting at the Main Menu of the User Interface, select Remote Management Setup.
2. Enter the IP address in the New Switch IP Settings section of the Remote Management
Setup screen.
3. Enter a Subnet Mask in the next field.
4. Click APPLY to make the change effective. Use Save Changes from the Main Menu to enter the IP address into NV-RAM.
Setting a Default Gateway
The default gateway parameter defines the IP address of a router or other network device to which IP packets are to be sent if destined for an interface outside of that in which the switch is operating. This parameter must be set if you are attempting to manage the switch from a remote network or across the
Internet.
1. Starting at the Main Menu of the User Interface, select Remote Management Setup.
2. Enter the Gateway IP address of the router in the Default Gateway field in the New Switch
IP Settings section of the Remote Management Setup screen.
3. Click APPLY to make the change effective. Use Save Changes from the Main Menu to enter the IP address into NV-RAM.
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Setting the Administrator Password
Management access to the switch is restricted based on the administrator password. Administrators have read/write access for parameters governing the SNMP agent. You should therefore assign a password to the default administrator as soon as possible, and store it in a safe place.
Setting Trap Destinations
If you wish to record SNMP traps, or events, generated by the switch, you must configure a destination for the Trap Receivers. A trap destination is the IP address of the computer system on which the Webbased manager is being run.
1. Starting at the Main Menu of the User Interface, select Management / Trap Receivers.
2. Select an entry for a Trap Receiver from the menu, then enter the IP address and community name.
3. Move to the Status field, and use the Space bar to select ENABLED.
4. Click APPLY to make the changes effective. Use Save Changes to enter the configuration into NV-RAM.
Saving Configuration Changes
Clicking the APPLY button makes any configuration change active, but only for the current session. If the switch is restarted (rebooted) without entering the configuration changes into the non-volatile RAM
(flash RAM), the configuration changes will be lost.
To enter configuration changes into the switch’s non-volatile RAM, select Save Changes from the main screen. Click on the Save Configuration button to enter the current configuration into NV-RAM. The configuration will then be loaded into the switch’s memory when it is restarted.
Figure 7-6. Save Changes window
Starting and Stopping the Web-based Manager
Do the following to use the web-based manager:
1. Start a Java-enabled Web browser from any machine with network access to the switch.
(Preferred browsers include Opera, Internet Explorer 5.0 or above, or Netscape Navigator 4.0 or above.)
2. Enter the IP address for the switch you want to manage in the URL field of the browser.
3. The screen below will appear, prompting you to enter the user name and password for management access.
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Figure 7-7. Password dialog box
1. Use the User Name, and Password previously entered in the Setting Up Web Management section. This will allow read/write access to the switch.
2. The full application will now launch. A four-frame page will display with the product graphic located in the upper right hand frame.
3. To stop the web-based manager, close the Web browser application.
Web-based Manager’s User Interface
The user interface provides access to various switch configuration and management screens, allows you to view performance statistics, and permits you to graphically monitor system status.
Areas of the User Interface
The user interface is divided into 3 distinct areas:
Area 1 Area 2
Area 3
Figure 7-8. Main Web-Manager window
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Area Function
1
2
Allows the selection of commands.
Presents a graphical near real-time image of the front panel of the switch. This area displays the switch’s ports and expansion modules, showing port activity, duplex mode, or flow control, depending on the specified mode. Various areas of the graphic can be selected for performing management functions, including the ports, expansion modules, management module, or the case.
3 Presents switch information based on your selection and the entry of configuration data.
CONFIGURING AND MONITORING
This section, arranged by topic, describes how to perform common monitoring and configuration tasks on a DES-3326 switch using the Web-based Manager, you can perform any of the tasks described in the following sections.
Screen Hierarchy
The contents of this chapter are arranged following the structure shown in the tables below. The first table shows the arrangement of the links and the configuration menus for Web-based management software when the switch is in Layer 2 Only mode. The second table shows the arrangement of the menus when the switch is in IP Routing (Layer 3) mode.
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Link Menus
Configuration IP Address
Switch Information
Configure Port
Switch Settings Switch Operation Mode
VLANs
Multicasting
Layer 2 Switch Settings
802.1Q Static VLANs
802.1Q Port Settings
Port VLAN ID (PVID)
Port Ingress Filter
Port GVRP Settings
Port GMRP Settings
IEEE 802.1Q Multicast Forwarding
Priority
Mirroring
IGMP Snooping Settings
Static Router Port Settings
MAC Address Priority
Target Port Selection
Port Mirroring Settings
STP Switch Settings Spanning Tree
Protocol
Configure STP Groups
STP Port Settings
Link Aggregation Link
Aggregation
Forwarding
Filtering
Management
MAC Forwarding
MAC Address Forwarding
MAC Filtering
MAC Address Filtering
Management Station IP
Community Strings
Trap Receivers
User Accounts Management
Serial Port Settings
Network
Monitoring
Port Utilization
Port Error
Statistics
Port Packet Analysis
Address Table Browse MAC Address Sequentially
Applications GVRP Status
Maintenance
GMRP Status
Browse Router Port
IGMP Snooping Table
Switch History
Update Firmware from Server
User Configuration File on Server
Save Settings to Server
Save History Log to Server
Save Changes
Factory Reset
Restart System
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The following table shows the relationship between the links and the configuration menus when the switch is in IP Routing (Layer 3) mode. Menus and screens added when the switch is in IP Routing mode are shown in italics.
Link Menus
Configuration
Switch
Settings
IP Address
Switch Information
Configure Port
Switch Operation Mode
Layer 2 Switch Settings
Layer 3 IP Routing Protocol Settings
Configure
Layer 3 IP
Networking
Setup IP Interfaces
MD5 Key Table Configuration
Route Redistribution Settings
RIP Settings RIP State
OSPF
Setup RIP
General
OSPF Area Setting
OSPF Interface Configuration
Virtual Interface Configuration
Area Aggregation Configuration
VLANs 802.1Q Static VLANs
802.1Q Port Settings
Port VLAN ID (PVID)
Port Ingress Filter
Port GVRP Settings
Multicasting
Port GMRP Settings
IEEE 802.1Q Multicast Forwarding
IP Multicasting Multicast Interface Configuration
IGMP Settings
DVMRP Settings
PIM-DM Settings
Multicasting Static Router Port Settings
Priority
Mirroring
MAC Address Priority
Target Port Selection
Spanning Tree
Protocol
Port Mirroring Settings
STP Switch Settings
Configure STP Groups
STP Port Settings
Link Aggregation Link
Aggregation
Forwarding MAC Forwarding
MAC Address Forwarding
IP Forwarding
Static/Default Route
Static ARP
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Filtering MAC Filtering
MAC Address Filtering
IP Filtering
IP Address Filtering
BOOTP/DHCP Relay BOOTP/DHCP
Relay
DNS Relay
Management
Static Setup
DNS Relay
Static Setup
Management Station IP
Community Strings
Trap Receivers
User Accounts Management
Serial Port Settings
Network
Monitoring
Port Utilization
Port Error
Statistics
Port Packet Analysis
Address Table Browse MAC Address Sequentially
Browse IP Address Sequentially
Routing Table
ARP Table
Default IP Address
OSPF LSDB Table
OSPF External LSDB Table
Applications GVRP
GMRP
Browse Router Port
IGMP Snooping
IP Multicast Forwarding Table
IGMP Group Table
DVMRP Routing Table
Switch History
Maintenance Update Firmware from Server
User Configuration File on Server
Save Settings to Server
Save History Log to Server
Save Changes
Factory Reset
Restart System
Setting Up The Switch
Basic Setup
This section will help prepare the Switch user by describing the Switch Information – Basic Settings,
IP Address, Configure Port, and Switch Settings windows.
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Switch Information
Click the Switch Information link in the Configuration menu.
Figure 7-9. Switch Information – Basic Settings window
The Switch Information window shows which (if any) external modules are installed, and the switch’s
MAC Address (assigned by the factory and unchangeable). In addition, the Boot PROM and Firmware
Version numbers are shown. This information is helpful to keep track of PROM and Firmware updates and to obtain the switch’s MAC address for entry into another network device’s address table – if necessary.
You can also enter the name of the System, its location, and the name and telephone number of the
System Administrator. It is recommended that the person responsible for the maintenance of the network system that this Layer 3 switch is installed on be listed here.
IP Address
Configuring the Switch’s IP Address
The BOOTP and DHCP Server options for assigning the switch an IP address and subnet mask are only available when the switch is in Layer 2 Only mode.
The IP Routing mode requires a manual entry of the IP address and subnet mask.
The Switch needs to have an IP address assigned to it so that an In-Band network management system
(for example, the Web Manager or Telnet) client can find it on the network. The IP Address window allows you to change the settings for the Ethernet interface used for in-band communication.
The fields listed under the Current Settings heading are those that are currently being used by the switch. Those fields listed under the New Settings heading are those that will be used after the Apply button is clicked.
To set the switch’s IP address:
Click the IP Address link in the Configuration menu.
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Figure 7-10. IP Address window
The switch’s factory default IP address is 10.90.90.90 with a subnet mask of 255.0.0.0
and a default gateway of 0.0.0.0. address:
To manually assign the switch’s IP address, subnet mask, and default gateway
Enter the appropriate IP address and subnet mask.
If you want to access the switch from a different interface from the one it is installed on, enter the IP address of the gateway. If you will manage the switch from the interface on which it is installed, you can leave the default address in this field.
To use the BOOTP or DHCP protocols to assign the switch an IP address, subnet mask, and default gateway address:
Use the Get IP From: <Manual> pull-down menu to choose from Manual, BOOTP, or DHCP. This selects how the switch will be assigned an IP address on the next reboot (or startup).
Note: The BOOTP and DHCP protocols are only available when the switch is in Layer 2 mode.
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The Get IP From: <Manual> options are:
Parameter Description
BOOTP
DHCP
The switch will send out a BOOTP broadcast request when it is powered up. The BOOTP protocol allows IP addresses, network masks, and default gateways to be assigned by a central BOOTP server. If this option is set, the Switch will first look for a BOOTP server to provide it with this information before using the default or previously entered settings.
The switch will send out a DHCP broadcast request when it is powered up. The DHCP protocol allows IP addresses, network masks, and default gateways to be assigned by a DHCP server. If this option is set, the switch will first look for a DHCP server to provide it with this information before using the default or previously entered settings.
Manual
Subnet Mask
Allows the entry of an IP address, Subnet Mask, and a Default
Gateway for the switch. These fields should be of the form
xxx.xxx.xxx.xxx, where each xxx is a number (represented in decimal form) between 0 and 255. This address should be a unique address on the network assigned for use by the network administrator. The fields which require entries under this option are as follows:
A Bitmask that determines the extent of the subnet that the Switch is on. Should be of the form xxx.xxx.xxx.xxx, where each xxx is a number (represented in decimal) between 0 and 255. The value should be 255.0.0.0 for a Class A network, 255.255.0.0 for a Class B network, and 255.255.255.0 for a Class C network, but custom subnet masks are allowed.
Default Gateway IP address that determines where packets with a destination address outside the current interface should be sent. This is usually the address of a router or a host acting as an IP gateway. If your network is not part of an intranet, or you do not want the Switch to be accessible outside your local network, you can leave this field unchanged.
Management VID This allows the entry of a VLAN ID (VID) from which a management station (a computer) will be allowed to manage the switch using
TCP/IP (in-band, or over the network). Management stations that are on VLANs other than the one entered in the Management VID field will not be able to manage the switch in-band unless their IP addresses are entered in the Management Station IP Addresses field. Any VID that has been configured on the switch can be entered in this field.
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SNMP Settings
Some settings must be entered to allow the switch to be managed from an SNMP-based Network
Management System such as SNMP v1 or to be able to access the Switch using the Telnet protocol or the Web Manager.
To setup the switch for remote management:
Click the Management Station IP link in the Management menu. The following screen appears:
Figure 7-11. Management Station IP Settings window
Management stations are computers on the network that will be used to manage the switch. You can limit the number of possible management stations by entering up to three IP addresses. If the three IP
Address fields contain all zeros (“0”), then any station with any IP address can access the switch to manage and configure it. If there is one or more IP addresses entered in the IP Address fields, then only stations with the IP addresses entered will be allowed to access the switch to manage or configure it.
Setting Up Trap Receivers
This allows the switch to send traps (messages about errors, etc.) to management stations on the network. Click the Community Strings link in the Management menu. The trap recipients can be setup from the following window:
Figure 7-12. Trap Receivers window
The Trap Receiving Station field is the IP address of a management station (a computer) that is configured to receive the SNMP traps from the switch.
The Community String is similar to a password in that stations that do not know the correct string cannot receive or request SNMP information from the switch.
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The Status field can be toggled between Enabled and Disabled to enable or disable the receipt of SNMP traps by the listed management stations.
Configure Ports
Click the Configure Ports link on the Configuration menu:
Figure 7-13. Configure Port window
Click on the port you want to configure on the DES-3326 Switch front panel display at the top of the
Web page.
Use the State pull-down menu to either enable or disable a given port.
Use the Speed/Duplex pull-down menu to either select the speed and duplex/half-duplex state of the port. Auto – auto-negotiation between 10 and 100 Mbps devices, full- or half-duplex. The Auto setting allows the port to automatically determine the fastest settings the device the port is connected to can handle, and then to use those settings. The other options are 100M/Full, 100M/Half, 10M/Full, and
10M/Half. There is no automatic adjustment of port settings with any option other than Auto.
Port Locking
A given port’s (or a range of port’s) dynamic MAC address learning can be locked such that the current source MAC addresses entered into the MAC address forwarding table can not be changed once the port lock is enabled. The port can be locked by toggling the Lock pull-down menu to Enabled, and clicking Apply.
This is a security feature that prevents unauthorized computers (with source MAC addresses unknown to the switch prior to locking the port (or ports)) from connecting to the switch’s locked ports and gaining access to the network.
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The following fields can be set:
Parameter Description
State <Enabled>
Speed/Duplex
<Auto>
Toggle the State field to either enable or disable a given port.
Toggle the Speed/Duplex field to either select the speed and duplex/half-duplex state of the port. Auto – autonegotiation between 10 and 100 Mbps devices, full- or halfduplex. The Auto setting allows the port to automatically determine the fastest settings the device the port is connected to can handle, and then to use those settings.
The other options are 100M/Full, 100M/Half, 10M/Full, and
10M/Half. There is no automatic adjustment of port settings with any option other than Auto.
Flow Control: Auto Displays the flow control scheme used for the various port configurations. Ports configured for full-duplex use 802.3x flow control, half-duplex ports use backpressure flow control, and Auto ports use an automatic selection of the two.
Lock <Disabled> Allows the selected port (or port’s) dynamic MAC address learning to be locked such that new source MAC addresses cannot be entered into the MAC address table for the locked port. It can be changed by toggling between Disabled and
Enabled.
Serial Port Settings
The Serial Port Settings window allows the configuration of the switch’s serial port and out-of-band
TCP/IP communications using SLIP.
Click on the Serial Port Settings link on the Management menu.
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Figure 7-14. Serial Port Settings window
Use the Select Protocol pull-down menu to select either the Console or the SLIP protocol.
The following fields can then be set:
Console Settings
Parameter Description
Baud Rate
Data Bits
Stop Bits
Auto-Logout
Displays the serial bit rate used to communicate with a management station. The console baud rate is
9600 bits per second.
Displays the number of bits that make up a word when communicating with the management station. The console interface uses 8 data bits.
Displays the number of bits used to indicate that a word has been completely transmitted. The console interface uses 1 stop bit.
This sets the time the interface can be idle before the switch automatically logs-out the user. The options are 2 mins, 5 mins, 10 mins,
15 mins, or Never.
SLIP Settings
Parameter
Baud Rate
203
Description
Sets the serial bit rate that will be used to communicate the next time
DES-3326 Layer 3 Fast Ethernet Switch User’s Guide the Switch is restarted. Applies only when the serial port is being used for out-of-band (SLIP) management; it does not apply when the port is used for the console port. Available speeds are 2,400, 9600, 19,200 and 38,400 bits per second. The default setting is 9600.
Local IP Address
Remote IP Address This is the IP address of the management station that will use the
SLIP protocol to communicate with the switch.
MTU
This is an IP address assigned to the serial port when it is used for SLIP communications.
Maximum Transfer Unit – this specifies the maximum packet size in bytes. Can be toggled between 1006 and 1500.
Switch Operation Mode
Putting the switch in IP Routing mode does not – by itself – enable IP routing. The switch must be configured to use IP interfaces before it is capable of IP routing.
The switch can operate in one of two modes:
1. Layer 2 Only, Support IEEE 802.1Q VLANs. The switching process is based upon the source and destination MAC addresses only. 802.1Q VLANs are supported and the switch is considered as a VLAN-tag aware device.
2. IP Routing, Support IEEE 802.1Q VLANs. The switching process is based upon the IP source and destination addresses, if present. If the IP addresses are not present, the switching process is based upon the MAC addresses (as in Layer 2 above). 802.1Q VLANs are supported and the switch is considered as a VLAN-tag aware device.
The switch must be rebooted when changing the operation mode before the new mode can take effect.
Changing the Switch Operation Mode
To change the switch’s operating mode:
On the Configuration menu, select the Switch Settings link, and then click Switch Operation Mode:
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Figure 7-15. Switch Operation Mode window
Use the Restart Mode pull-down menu to select one of the two switch operation modes: Layer 2,
Support IEEE 802.1Q VLANs and IP Routing, Support IEEE 802.1Q VLANs.
To make a change in the operation mode of the switch effective, click Apply.
The switch will then save the changes made during the current session and reboot. The switch must be rebooted to change the operation mode.
Menu Changes with Switch Operating Mode
Once the switch is configured for IP Routing (Layer 3 Switching), and rebooted, the Web Manager menu adds some functions compared to the Layer 2 Only mode.
Switch Settings
The Switch Settings menu allows for various functions − some of which are configured on different console screens − to be enabled or disabled on the switch (globally), without altering the individual function’s configuration. Thus, the Distance-Vector Multicast Protocol (DVMRP) is configured from the
Configuration → Multicasting → IP Multicasting → DVMRP Settings window, but can be enabled or disabled from the Layer 3 IP Routing Protocol Settings window − without changing the DVMRP configuration entered in the DVMRP Settings window.
Layer 2 Switch Settings
To access the Layer 2 Switch Settings window, click Layer 2 Switch Settings (Configuration →
Switch Settings).
Figure 7-16. Layer 2 Switch Settings window
The following fields can then be set:
Parameter Description
MAC Address Aging
Time (10 …1000000 sec)
Specifies the length of time a learned MAC Address will remain in the forwarding table without being accessed
(that is, how long a learned MAC Address is allowed to remain idle). The Aging Time can be set to any value between 10 and 1,000,000 seconds.
Broadcast/Multicas t Storm Mode
This field can be toggled among Broadcast, Multicast, BCST
& MCST, and Disabled using the space bar. These options
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<Disabled> dictate, globally, the switch’s reaction to Broadcast storms and/or Multicast storms, triggered at the threshold set below.
Upper Threshold for
Base ports <128>
This is the number of thousands Broadcast/Multicast packets per second received by the switch – on one of the
Master Ports – that will trigger the switch’s reaction to a
Broadcast/Multicast storm.
Upper Threshold for
Module ports <128>
This is the number of thousands Broadcast/Multicast packets per second received by the switch – on one of the module ports – that will trigger the switch’s reaction to a
Broadcast/Multicast storm.
GVRP <Disabled>
GMRP <Disabled>
Allows the Group VLAN Registration Protocol (GVRP) to be globally Enabled or Disabled on the switch.
Allows the Group Multicast Registration Protocol (GMRP) to be globally Enabled or Disabled on the switch.
Switch Settings − Layer 3 IP Routing Protocol Settings
The Layer 3 Switch Settings menu only allows the available multicasting
protocols to be enabled or disabled − globally − on the switch.
The multicasting and routing protocols are setup under the Multicasting and the Configure Layer 3 −
IP Networking menus.
To access the Layer 3 IP Routing Protocol Settings window, go to the Configuration menu, select
Switch Settings, and then click Layer 3 IP Routing Protocol Settings:
Figure 7-17. Layer 3 IP Routing Protocol Settings window
The following fields can then be set:
Parameter Description
DVMRP <Disabled> Allows the Distance-Vector Multicast
Routing Protocol (DVMRP) to be
Enabled or Disabled globally on the
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PIM-DM state
<Disabled> switch.
Allows the Protocol Independent
Multicast − Dense Mode (PIM-DM) multicast routing protocol to be
Enabled or Disabled globally on the switch.
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Advanced Setup
Changing switch operation mode setting changes some of the menus and configuration options for the
Advanced Setup of the switch. The configuration data for each mode is, however, saved when the switch’s operating mode is changed.
Configuring VLANs
The switch allows the assignment of an IP interface to each VLAN, in IP
Routing mode. The VLANs must be configured prior to setting up the IP
interfaces.
VLANs by Switch Operating Mode
To create a new 802.1Q VLAN:
The VLAN menu adds an entry to edit the VLAN definitions and to configure the port settings for IEEE
802.1Q VLAN support. Go to the Configuration menu, select VLANs, and click 802.1Q Static VLANs:
Figure 7-18. 802.1Q Static VLANs window
To delete an existing 802.1Q VLAN, click the X icon in the Delete column that corresponds to the
VLAN you want to delete.
To create a new 802.1Q VLAN, click the New hyperlink:
Figure 7-19. 802.1Q Static VLANs Entry Settings – Add window
To edit an existing 802.1Q VLAN, click the Hand icon:
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Figure 7-20. 802.1Q Static VLANs Entry Settings – Edit window
The following fields can then be set:
Parameter
VLAN ID (VID)
Port
Tag
Egress
Forbidden
Description
Allows the entry of the name of an existing VLAN. VLANs can be identified by either the VID or the VLAN name.
Allows an individual port to be specified as member of a
VLAN.
Allows an individual port to be specified as either Tagging or
Untagging. No Check in the Tag field, untagging, specifies the port as an Untagging member of the VLAN. When an untagged packet is transmitted by the port, the packet header remains unchanged. When a tagged packet exits the port, the tag is stripped and the packet is changed to an untagged packet. A Check in the Tag field, tagging, specifies the port as a Tagging member of the VLAN. When an untagged packet is transmitted by the port, the packet header is changed to include the 32-bit tag associated with the PVID (Port VLAN Identifier – see below). When a tagged packet exits the port, the packet header is unchanged.
Egress Member - specifies the port as being a static member of the VLAN. Egress Member Ports are ports that will be transmitting traffic for the VLAN. These ports can be either tagged or untagged.
Forbidden Non-Member - specifies the port as not being a member of the VLAN and that the port is forbidden from becoming a member of the VLAN dynamically.
Choose which ports will be members of the new VLAN and enter their membership status in the Port field. Next, determine which of the ports that are members of the new VLAN will be Tagged or Untagged ports.
To set a port as either a Tagged or an Untagged port:
Check the Tag click-box for each port that will be a tagging port. Each port’s state can be set by clicking the port’s click-box.
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If the port is attached to a device that is not IEEE 802.1Q VLAN compliant (VLAN-tag unaware), then the port should be set to Untagged (no marker in the port’s Tag click-box).
If the port is attached to a device that is IEEE 802.1Q VLAN compliant, (VLAN-tag aware), then the port should be set to Tagged (has a marker in the port’s Tag click-box).
Click Apply to make the additions/deletions effective for the current session. To enter the IP Interfaces into non-volatile RAM, use the Save Changes window on the Maintenance menu.
To configure the member ports of an 802.1Q VLAN:
Go to the Configuration menu, select VLANs, choose 802.1Q Port Settings, and then click Port VLAN
(PVID):
Figure 7-21. Port VLAN ID (PVID) window
The following field can be set:
Parameter
PVID
Description
A Port VLAN Identifier is a classification mechanism that associates a port with a specific
VLAN and is used to make forwarding decisions for untagged packets received by the port. For example, if port #2 is assigned a
PVID of 3, then all untagged packets received on port #2 will be assigned to VLAN 3. This number is generally the same as the VID# number assigned to the port in the Edit
802.1Q VLANs menu above.
Each port can be configured to use an ingress filter.
To configure the member ports of an 802.1Q VLAN to use and ingress filter:
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Go to the Configuration menu, select VLANs, choose 802.1Q Port Settings, and then click Port
Ingress Filter:
Figure 7-22. Port Ingress Filter window
The following field can be set:
Parameter Description
Ingress Filter
<Disable>
This field can be toggled using the space bar between Enabled and
Disabled. Enabled enables the port to compare the VID tag of an incoming packet with the PVID number assigned to the port. If the two are different, the port filters
(drops) the packet. Disabled disables
Ingress filtering.
Each port can be configured to use the Group VLAN Registration Protocol (GVRP).
To configure the member ports of an 802.1Q VLAN to use GVRP:
Go to the Configuration menu, select VLANs, choose 802.1Q Port Settings, and then click Port GVRP
Settings:
Figure 7-23. Port GVRP Settings window
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The following field can be set:
Parameter Description
GVRP <Disabled> The Group VLAN Registration
Protocol (GVRP) enables the port to dynamically become a member of a
VLAN.
Each port can be configured to use the Group Multicast Registration Protocol (GMRP).
To configure the member ports of an 802.1Q VLAN to use GMRP:
Go to the Configuration menu, select VLANs, choose 802.1Q Port Settings, and then click Port
GMRP Settings:
Figure 7-24. Port GMRP Settings window
The following field can be set:
Parameter Description
GMRP <Disabled> Group Multicast Registration
Protocol (GMRP) enables the port to dynamically become a member of a multicast group.
Setting Up IP Interfaces
A VLAN that does not have a corresponding IP interface defined for it, will function as a Layer 2 Only VLAN – regardless of the Switch Operation mode.
Each VLAN must be configured prior to setting up the VLAN’s corresponding IP interface.
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An example is presented below:
VLAN Name
System (default)
Engineer
Marketing
Finance
Sales
VID
3
4
1
2
5
Switch Ports
5, 6, 7, 8, 21, 22, 23, 24
9, 10, 11, 12
13, 14, 15, 16
17, 18, 19, 20
1, 2, 3, 4
Table 6-3. VLAN Example – Assigned Ports
In this case, 6 IP interfaces are required, so a CIDR notation of 10.32.0.0/11 (or a 11-bit) addressing scheme will work. This addressing scheme will give a subnet mask of
11111111.11100000.00000000.00000000 (binary) or 255.224.0.0 (decimal).
Using a 10.xxx.xxx.xxx IP address notation, the above example would give 6 network addresses and 6 interfaces.
Any IP address from the allowed range of IP addresses for each interface can be chosen as an IP address for an IP interface on the switch.
For this example, we have chosen the next IP address above the network address for the IP interface’s
IP Address:
VLAN Name VID
System (default) 1
Network Number IP Address
10.32.0.0 10.32.0.1
Table 6-4. VLAN Example – Assigned IP Interfaces
The 6 IP interfaces, each with an IP address (listed in the table above), and a subnet mask of
255.224.0.0 can be entered into the Setup IP Interface window.
To setup IP Interfaces on the switch:
Go to the Configuration menu, select Configure Layer 3 – IP Networking, and then click Setup IP
Interfaces:
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Figure 7-25. Setup IP Interface window
To setup an new IP interface, click the New icon:
Figure 7-26. Setup IP Interface – Add window
To edit an existing IP interface, click on the Hand icon:
Figure 7-27. Setup IP Interface – Edit window
Choose a name for the interface to be added and enter it in the Interface Name field (if you are editing an IP Interface, the Name will already be in the top field as seen in the window above). Enter the interface’s IP address and subnet mask in the corresponding fields. Pull the Active pull-down menu to
Yes and click Apply to enter to make the IP interface effective. Use the Save Changes window on the
Maintenance menu to enter the changes into NV-RAM.
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The following fields can be set:
Parameter
Subnet Name
IP Address
Subnet Mask
VID
Active <Yes>
Description
This field allows the entry of a name for the IP interface. The default IP interface is named “System”.
This field allows the entry of an IP address to be assigned to this IP interface.
This field allows the entry of a subnet mask to be applied to this IP interface.
This field allows the entry of the
VLAN ID number for the VLAN the IP interface belongs to.
This field is toggled between Yes and
No using the space bar. This entry determines whether the interface will be active or not.
Layer 3 IP Networking
To access the Layer 3 IP Networking menus, select Configure Layer 3 - IP Networking on the
Configuration menu.
If an IP Interface is created while RIP is enabled, the TX Mode default will be
V2 Only and the RX Mode default will be V1 and V2
Setup the Routing Information Protocol (RIP)
To access the RIP State window, select RIP State (Configuration − Configure Layer 3 – IP
Networking − RIP Settings − RIP State).
Figure 7-28. RIP State window
This window allows RIP to be globally enabled and disabled on the switch without changing its configuration.
To configure RIP on the switch, highlight Setup RIP (Configuration → Configure Layer 3 – IP
Networking → RIP Settings → Setup RIP).
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Figure 7-29. Setup RIP window
To edit a RIP configuration, click the Hand icon.
Figure 7-30. Setup RIP – Edit window
The following fields can be set:
Parameter Description
Subnet Name
TX Mode
<Disabled>
RX Mode
<Disabled>
Password
Authentication
The name of the IP interface on which RIP is to be setup. This interface must be previously configured on the Switch.
Toggle among Disabled, V1 Only, V1
Compatible, and V2 Only. This entry specifies which version of the RIP protocol will be used to transmit RIP packets. Disabled prevents the transmission of RIP packets.
Toggle among Disabled, V1 Only, V2
Only, and V1 and V2. This entry specifies which version of the RIP protocol will be used to interpret received RIP packets. Disabled prevents the reception of RIP packets.
A password to be used to authenticate communication between routers on the network.
Toggle between Disabled and
Enabled to specify that routers on the network should us the Password above to authenticate router table exchanges.
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OSPF
MD5 Key Table Configuration
The MD5 Key Table Configuration menu allows the entry of a 16-character Message Digest − version
5 (MD5) key that can be used to authenticate every packet exchanged between OSPF routers. It is used as a security mechanism to limit the exchange of network topology information to the OSPF routing domain.
MD5 Keys created here can be used in the OSPF Interface Configuration menu below.
Key
Figure 7-31. MD5 Key Table window
The following fields can be set:
Parameter
Key ID
Description
A number from 1 to 255 used to identify the MD5 Key.
A alphanumeric string of between 1 and 16 case-sensitive characters used to generate the Message Digest which is in turn, used to authenticate OSPF packets within the OSPF routing domain.
Setup OSPF
Figure 7-32. Setup OSPF window
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The following parameters can be set or are displayed:
Parameter Description
OSPF Route ID
Current Route ID Displays the OSPF Route ID currently in use by the switch. This
Route ID is displayed as a convenience to the user when changing the switch’s OSPF Route
ID.
AS Border Router Autonomous System Border Router − displays whether or not the switch is configured as an AS Border Router.
State
A 32-bit number (in the form of an IP address − xxx.xxx.xxx.xxx) that uniquely identifies the switch in the
OSPF domain. It is common to assign the highest IP address assigned to the switch (router). In this case, it would be
10.255.255.255, but any unique 32bit number will do. If 0.0.0.0 is entered, the highest IP address assigned to the switch will become the OSPF Route ID.
Allows OSPF to be enabled or disabled globally on the switch without changing the OSPF configuration.
OSPF Area Setting
This menu allows the configuration of OSPF Area IDs and to designate these areas as either Normal or
Stub. Normal OSPF areas allow Link-State Database (LSDB) advertisements of routes to networks that are external to the area. Stub areas do not allow the LSDB advertisement of external routes. Stub areas use a default summary external route (0.0.0.0 or Area 0) to reach external destination.
Figure 7-33. OSPF Area Setting window
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The following fields can be set or are displayed:
Parameter Description
Area ID
Type
A 32-bit number in the form of an IP address (xxx.xxx.xxx.xxx) that uniquely identifies the OSPF area in the OSPF domain.
This field can be toggled between
Normal and Stub using the space bar. When it is toggled to Stub, additional fields appear − Stub
Import Summary LSA and Stub
Default Cost.
Stub Import Sum. Displays whether or not the selected
Area will allow Summary Link-State
Advertisements (Summary LSAs) to be imported into the area from other areas.
Stub Default Cost Displays the default cost for the route to the stub of between 0 and
65,535. The default is none (0).
Remove Allows for the removal of the selected
OSPF Area from the list.
OSPF Interface Configuration
Figure 7-34. OSPF Interface Configuration window
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The following fields can be set:
Parameter
Interface Name
Area ID
Router Priority
Hello Interval
Dead Interval
State
Auth Type
Metric
Description
Allows the entry of the name of an IP interface previously configured on the switch.
Allows the entry of an OSPF Area ID configured above.
Allows the entry of a number between 1 and 255 representing the OSPF priority of the selected area. If a
Router Priority of 0 is selected, the switch cannot be elected as the Designated Router for the network.
Allows the specification of the interval between the transmission of OSPF Hello packets, in seconds. Between
5 and 65535 seconds can be specified. The Hello Interval,
Dead Interval, Authorization Type, and Authorization Key should be the same for all routers on the same network.
Allows the specification of the length of time between the receipt of Hello packets from a neighbor router before the selected area declares that router down. An interval between 5 and 65535 seconds can be specified. The Dead
Interval must be evenly divisible by the Hello Interval.
Allows the OSPF interface to be disabled for the selected area without changing the configuration for that area.
This field can be toggled between None, Simple, and MD5 using the space bar. This allows a choice of authorization schemes for OSPF packets that may be exchanged over the
OSPF routing domain. None specifies no authorization.
Simple uses a simple password to determine if the packets are from an authorized OSPF router. When Simple is selected, the Auth Key field allows the entry of a 8 character password that must be the same as a password configured on a neighbor OSPF router. MD5 uses a cryptographic key entered in the MD5 Key Table
Configuration menu. When MD5 is selected, the Auth Key
ID field allows the specification of the Key ID as defined in the MD5 configuration above. This must be the same MD5
Key as used by the neighboring router.
This field allows the entry of a number between 1 and
65,535 that is representative of the OSPF cost of reaching the selected OSPF interface. The default metric is 1.
Virtual Interface Configuration
Virtual Interfaces are used by OSPF to link areas that do not have a physical connection to the backbone (also called Area 0) or to link areas of the backbone itself that are discontinuous. This allows routing information to flow from an area that is physically disconnected from area 0 into area 0 by configuring an interface across one of the areas previously defined above.
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Figure 7-35. Virtual Interface Configuration window
The following fields can be set or are displayed:
Parameter
Transit Area ID
Neighbor Router
Status
Description
Allows the entry of an OSPF Area ID
− previously defined on the switch − that allows a remote area to communicate with the backbone
(area 0). A Transit Area cannot be a
Stub Area or a Backbone Area.
The OSPF router ID for the remote router. This is a 32-bit number in the form of an IP address
(xxx.xxx.xxx.xxx) that uniquely identifies the remote area’s Area
Border Router.
Displays the current status (UP or
DOWN) of the corresponding OSPF
Virtual Interface.
Area Aggregation Configuration
Area Aggregation allows all of the routing information that may be contained within an area to be aggregated into a summary LSDB advertisement of just the network address and subnet mask. This allows for a reduction in the volume of LSDB advertisement traffic as well as a reduction in the memory overhead in the switch used to maintain routing tables.
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Figure 7-36. OSPF Area Aggregation Configuration window
The following fields can be set or are displayed:
Parameter
Area ID
Network Number
Advertisement
Description
Allows the entry the OSPF Area ID for which the routing information will be aggregated. This Area ID must be previously defined on the switch.
Sometimes called the Network
Address. The 32-bit number in the form of an IP address that uniquely identifies the network that corresponds to the OSPF Area above.
This field can be toggled between Yes and No using the space bar. It determines whether or not the selected OSPF Area will advertise it’s summary LSDB (Network-Number and Network-Mask) or not.
Route Redistribution Settings
Route redistribution allows routers on the network − that are running different routing protocols − to exchange routing information. This is accomplished by comparing the routes stored in the various router’s routing tables and assigning appropriate metrics. This information is then exchanged among the various routers according to the individual routers current routing protocol. The DES-3326 can redistribute routing information between the OSPF and RIP routing protocols to all routers on the network that are running OSPF or RIP. Routing information entered into the Static Routing Table on the local DES-3326 switch is also redistributed.
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Figure 7-37. Route Redistribution Settings window
The following fields can be set or are displayed:
Parameter
Source Protocol
Dest. Protocol
Metric Type
Metric
Description
Allows the selection of the protocol of the source device. Available choices are RIP, OSPF, or Static.
Allows the selection of the protocol of the destination device. Available choices are RIP and OSPF.
Allows the selection of one of two methods for calculating the metric value. Type-1 calculates the metric
(for RIP to OSPF) by adding the destination’s interface cost to the metric entered in the Metric field.
Type-2 uses the metric entered in the
Metric field without change. This field applies only when the destination field is OSPF.
Allows the entry of an OSPF interface cost. This is analogous to a Hop
Count in the RIP routing protocol.
Multicasting
Layer 2 Multicast Setup
The following menus are used to setup the switch’s Layer 2 multicasting features.
IGMP Snooping Settings
To configure IGMP Snooping:
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Open the Configuration menu, select Multicasting, and click IGMP Snooping Settings:
Figure 7-38. IGMP Control Setup window
To configure IGMP Snooping:
The following fields can be set:
Parameter
VID
State <Disabled>
Query
Max Response
Robustness Var
Description
Allows the entry of the VLAN ID (VID) for which IGMP Snooping is to be configured.
This field can be switched using the pull-down menu between Disabled and Enabled. This is used to enable or disable IGMP Snooping for the specified VID.
Allows the entry of a value between 1 and 65535 seconds, with a default of
125 seconds. This specifies the length of time between sending IGMP queries.
Sets the maximum amount of time allowed before sending an IGMP response report. A value between 1 and 25 seconds can be entered, with a default of 10 seconds.
A tuning variable to allow for subnetworks that are expected to lose a large number of packets. A value between 2 and 255 can be entered, with larger values being specified for sub-networks that are expected to lose larger numbers of packets.
IEEE 802.1Q Multicast Forwarding
To edit the IEEE802.1 Multicast Forwarding settings:
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Click the IEEE802.1Q Multicast Forwarding link on the Multicasting menu:
Figure 7-39. Setup IEEE 802.1Q Multicast Forwarding window
When the switch is in Layer 2 operating mode, IEEE 802.1Q multicast forwarding allows the static entry of multicast MAC addresses, which will be sources of multicast packets, and switch port numbers, to which these multicast packets will be forwarded. The ports that can be chosen as the destination for multicast packets from the above MAC multicast address, are limited to the ports belonging to the VLAN that corresponds to the VID entered in the VID field.
Each port of a given VLAN can be configured as an egress member, a forbidden non-member, or as a non-member of the multicast group that will receive multicast packets from the multicast MAC address, by clicking the click-box below each port of the VLAN to the appropriate code.
The following fields can be set:
Parameter Description
MAC Address
VID
Egress
Forbidden
Allows the entry of the MAC address of a static multicast group member.
Allows the specification of the VLAN
ID (VID) of the VLAN the static multicast group member belongs to.
Egress Member - specifies the port as being a static member of the multicast group. Egress Member
Ports are ports that will be transmitting traffic for the multicast group.
Forbidden Non-Member - specifies the port as not being a member of the multicast group and that the port is forbidden from becoming a member of the multicast group dynamically.
Static Router Port Settings
A static router port is a port that has a multicast router attached to it. Generally, this router would have a connection to a WAN or to the Internet. Establishing a router port will allow multicast packets
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(IGMP) coming from the network to be propagated to the router.
A router port has the following behavior:
• All IGMP Report packets will be forwarded to the router port.
• IGMP queries (from the router port) will be flooded to all ports.
• All UDP multicast packets will be forwarded to the router port. Because routers do not send
IGMP reports or implement IGMP snooping, a multicast router connected to the router port of the Layer 3 switch would not be able to receive UDP data streams unless the UDP multicast packets were all forwarded to the router port.
• A router port will be dynamically configured when IGMP query packets, RIPv2 multicast,
DVMRP multicast, PIM-DM multicast packets are detected flowing into a port.
To setup a static router port:
Click the Static Router Port Settings link on the Multicasting menu:
Figure 7-40. Static Router Port Settings window
To delete an existing static router port configuration, click the Delete icon.
To add a static router port configuration, click the New icon:
Port
Figure 7-41. Static Router Port Settings − Add window
The following fields can be set:
Parameter
VID
Description
Allows the specification of the VLAN
ID (VID) of the VLAN the static router port belongs to.
Each port can be set individually as a router port by clicking the port’s click-box entry.
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Layer 3 Multicasting
When the switch is in IP Routing mode, several functions supporting IP multicasting are added to the
Multicasting menu.
Multicast Interface Configuration
To setup IP multicasting on the switch:
Open the Multicasting menu (under Configuration), select IP Multicasting, and click Multicast
Interface Configuration:
.
Figure 7-42. Multicast Interface Configuration window
This menu allows the assignment of a multicast routing protocol to an IP interface. The IP interface must have been previously configured on the switch.
In addition, IGMP may be enabled or disabled for the selected IP interface.
The available multicast protocols are the Protocol Independent Multicast – Dense Mode (PIM-DM), and the Distance-Vector Multicast Routing Protocol (DVMRP).
INACT is not a multicast routing protocol. It is used to make a given interface inactive for IP Multicast routing and can still route IP traffic.
The following fields can be set:
Parameter Description
Interface Name
IGMP <Enabled>
Allows the entry of the name of the IP interface that is to be configured for multicasting. This must be a previously configured IP interface.
This field can be toggled between Enabled and Disabled using the pull-down menu. This will enable or disable IGMP for the IP interface entered above.
Multicast Routing
Protocol <INACT>
This field can be toggled between Protocol Independent
Multicasting – Dense Mode (PIMDM), Distance Vector
Multicasting Routing Protocol (DVMRP), and INACT
(inactive). INACT is not a multicast routing protocol. It is used to make a given interface inactive for IP Multicast routing yet can still route IP traffic.
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IGMP Settings
Figure 7-43. IGMP Interface Setup window
This menu allows the configuration of IGMP for each IP interface configured on the switch. IGMP can be configured as Version 1 or 2 by toggling the Version field using the pull-down menu. The length of time between queries can be varied by entering a value between 1 and 65,535 seconds in the Query field.
The maximum length of time between the receipt of a query and the sending of an IGMP response report can be varied by entering a value in the Max Resp field.
The Robustness Var field allows IGMP to be ‘tuned’ for sub-networks that are expected to lose a lot of packets. A high value (max. 255) for the robustness variable will help compensate for ‘lossy’ subnetworks. A low value (min. 2) should be used for less ‘lossy’ sub-networks.
The following fields can be set:
Parameter Description
Interface Name
<System>
Allows the entry of the name of the IP interface that is to be configured for IGMP. This must be a previously configured IP interface.
Version <2> Enter the IGMP version (1 or 2) that will be used to interpret
IGMP queries on the interface.
Query <125>
Max Resp <10>
Allows the entry of a value between 1 and 65535 seconds, with a default of 125 seconds. This specifies the length of time between sending IGMP queries.
Sets the maximum amount of time allowed before sending an
IGMP response report. A value between 1 and 25 seconds can be entered, with a default of 10 seconds.
Robustness Var
<2> lose a large number of packets. A value between 2 and 255 can be entered, with larger values being specified for interface that are expected to lose larger numbers of packets.
IP Displays the IP address corresponding to the IP interface name entered above.
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DVMRP Settings
To configure DVMRP for an IP interface:
Click the DVMRP Settings link on the IP Multicasting menu:
Figure 7-44. DVMRP Interface Configuration window
This menu allows the Distance-Vector Multicast Routing Protocol to be configured for each IP interface defined on the switch.
The Distance Vector Multicast Routing Protocol (DVMRP) is a hop-based method of building multicast delivery trees from multicast sources to all nodes of a network. Because the delivery trees are ‘pruned’ and ‘shortest path’, DVMRP is relatively efficient. Because multicast group membership information is forwarded by a distance-vector algorithm, propagation is slow. DVMRP is optimized for high delay (high latency) relatively low bandwidth networks, and can be considered as a ‘best-effort’ multicasting protocol.
DVMRP resembles the Routing Information Protocol (RIP), but is extended for multicast delivery. It relies upon RIP hop counts to calculate ‘shortest paths’ back to the source of a multicast message, but defines a ‘route cost’ to calculate which branches of a multicast delivery tree should be ‘pruned’ – once the delivery tree is established.
When a sender initiates a multicast, DVMRP initially assumes that all users on the network will want to receive the multicast message. When an adjacent router receives the message, it checks its unicast routing table to determine the interface that gives the shortest path (lowest cost) back to the source. If the multicast was received over the shortest path, then the adjacent router enters the information into its tables and forwards the message. If the message is not received on the shortest path back to the source, the message is dropped.
Route cost is a relative number that is used by DVMRP to calculate which branches of a multicast delivery tree should be ‘pruned’. The ‘cost’ is relative to other costs assigned to other DVMRP routes throughout the network.
The higher the route cost, the lower the probability that the current route will be chosen to be an active branch of the multicast delivery tree (not ‘pruned’) – if there is an alternative route.
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The following fields can be set:
Parameter Description
Interface
Name<System>
IP Address
Allows the entry of the name of the IP interface for which
DVMRP is to be configured. This must be a previously defined IP interface.
Displays the IP address corresponding to the IP Interface name entered above.
Probe Interval
<10>
This field allows an entry between 0 and 65,535 seconds and defines the interval between ‘probes’. The default is
10.
Nbr Report Timer
<35>
This field allows an entry between 1 and 65,535 seconds and defines the time period for DVMRP will hold Neighbor
Router reports before issuing poison route messages. The default is 35 seconds.
Route Cost <1>
State <Disabled>
This field allows an entry between 1 and 255 and defines the route cost for the IP interface. The DVMRP route cost is a relative number that represents the real cost of using this route in the construction of a multicast delivery tree.
It is similar to, but not defined as, the hop count in RIP.
The default cost is 1.
This field can be toggled between Enabled and Disabled and enables or disables DVMRP for the IP interface. The default is Disabled.
PIM-DM Settings
To configure PIMDM for an IP interface:
Click the PIMDM Interface Configuration link:
Figure 7-45. PIM-DM Interface Configuration window
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The Protocol Independent Multicast – Dense Mode (PIM-DM) protocol should be used in networks with a low delay (low latency) and high bandwidth as PIM-DM is optimized to guarantee delivery of multicast packets, not to reduce overhead.
The PIM-DM multicast routing protocol is assumes that all downstream routers want to receive multicast messages and relies upon explicit prune messages from downstream routers to remove branches from the multicast delivery tree that do not contain multicast group members.
PIM-DM has no explicit ‘join’ messages. It relies upon periodic flooding of multicast messages to all interfaces and then either waiting for a timer to expire (the Join/Prune Interval) or for the downstream routers to transmit explicit ‘prune’ messages indicating that there are no multicast members on their respective branches. PIM-DM then removes these branches (‘prunes’ them) from the multicast delivery tree.
Because a member of a pruned branch of a multicast delivery tree may want to join a multicast delivery group (at some point in the future), the protocol periodically removes the ‘prune’ information from its database and floods multicast messages to all interfaces on that branch. The interval for removing
‘prune’ information is the Join/Prune Interval.
The following fields can be set:
Parameter Description
Interface Name
IP Address
Allows the entry of the name of the
IP interface for which PIM-DM is to be configured. This must be a previously defined IP interface.
Displays the IP address for the IP interface named above.
Hello Interval <30
>
This field allows an entry of between
1 and 18724 seconds and determines the interval between sending Hello packets to other routers on the network. The default is 30 seconds.
Join/Prune
Interval <60 >
State <Disabled>
This field allows an entry of between
0 and 18724 seconds. The default is
60 seconds.
This field can be toggled between
Enabled and Disabled using the pulldown menu, and is used to enable or disable PIM-DM for the IP interface.
The default is Disabled.
Port Mirroring
To configure a port for port mirroring:
Click the Mirroring link and then the Target Port Selection link:
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Figure 7-46. Target Port Selection window
The target port is the port where information will be duplicated and sent for capture and network analysis. This is the port where a network analyzer would be attached to capture packets duplicated from the source port.
To select the source port(s) for mirroring, click the Port Mirroring Settings link on the Mirroring menu
(under Configuration):
Figure 7-47. Setup Mirror Port Config window
Up to 25 entries can be made to the port mirroring table, but it should be noted that a faster port (a
1000 Mbps Gigabit Ethernet port, for example) should not be mirrored to a slower port (one of the 24
100 Mbps Fast Ethernet port), because many packets will be dropped.
The following fields can be set:
Parameter Description
Source Port Allows the entry of the port number of the port to be mirrored. This port is the source of the packets to be duplicated and forwarded to the
Target port.
Direction <Ingress> This field can be toggled between
Either, Ingress and Egress. Ingress mirrors only received packets, while
Egress mirrors only transmitted packets.
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Priority
To configure a forwarding priority for a given MAC address:
Click the Priority link on the Configuration menu:
Figure 7-48. Setup MAC Address Priority window
The following fields can be set:
Parameter
MAC Address
VID
Level <Low>
State <Src>
Description
Allows the entry of the MAC address of the station for which priority queuing is to be specified.
Allows the entry of the VLAN ID (VID) of the VLAN to which the MAC address below is a member of.
This field can be toggled using the pull-down menu between Low, Med-L
(Medium Low), Med-H (Medium
High), and High, corresponding to the priority of packets sent to or transmitted from the MAC address entered above.
This field can be toggled using the pull-down menu between Src
(Source), Dst (Destination), and
Either, corresponding to whether the
MAC address entered above will be transmitting packets (a source), receiving packets (a destination) or both (either).
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Filtering
Layer 2 Filtering
To enter a MAC address into the filtering table:
Select Filtering on the Configuration menu, choose MAC Filtering, and then click MAC Address
Filtering:
Figure 7-49. Setup MAC Address Filter window
When the switch is in Layer 2 Only operating mode, MAC addresses can be entered into the static filtering table. The switch can be configured to filter packets from this MAC address (a source), or to it
(a destination). The switch can also be configured to filter all packets to or from this MAC address
(either a source or a destination).
The following fields can be set:
Parameter Description
MAC Address
VID
State <Scr>
Allows the entry of a MAC address to be filtered from the switch. This address must be a unicast MAC address.
Allows the entry of the VLAN ID (VID) of the VLAN to which the MAC address below is a member of.
This field can be toggled using the pull-down menu between Src
(Source), Dst (Destination), and
Either, corresponding to whether the
MAC address entered above will be transmitting packets (a source), receiving packets (a destination) or both (either).
Layer 3 (IP Routing) Filtering
With the switch configured to Layer 3 Operation mode, both MAC and IP addresses can be entered into the filtering table, using their respective entry menus. To enter an address, open Configuration, select
Filtering, choose MAC Filtering, and then click MAC Address Filtering:
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Figure 7-50. Filter Address Setup window
The following fields can be set:
Parameter Description
Address <0.0.0.0> Allows the entry of an IP address to be filtered from the switch.
State <DstAddr> This field can be toggled between
SrcAddr (source), DstAddr.
(destination), and DstSrcAddr. The IP address entered into the filtering table can be filtered as a source
(packets will not be received from the
IP address), as a destination (packets will not be transmitted to the IP address), or as either a source or destination (packets will not be received from or transmitted to the IP address.
Forwarding
Layer 2 Forwarding
To enter a MAC address into the switch’s forwarding table:
Select Forwarding on the Configuration menu, choose MAC Forwarding, and click MAC Address
Forwarding:
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Figure 7-51. Setup Static Unicast MAC Forwarding window
The following fields can be set:
Parameter Description
MAC Address
VID
Port
Allows the entry of the MAC address of an end station that will be entered into the switch’s static forwarding table.
Allows the entry of the VLAN ID (VID) of the VLAN the MAC address below is a member of.
Allows the entry of the port number on which the MAC address entered above resides.
IP Forwarding
With the switch in Layer 3 Operation mode, entries into the switch’s forwarding table can be made using both MAC addresses and IP addresses. Static IP forwarding is accomplished by the entry of an IP address into the Static IP Routing table.
Static Address Resolution Protocol (ARP) entrees can also be made from the Forwarding menu.
Click the Static/Default Routes link on the IP Forwarding menu (under Configuration →
Forwarding):
Figure 7-52. Static/Default Routes window
To delete an existing static/default route, click the X icon under the Delete column corresponding to the entry you want to delete.
To add a new static/default route, click the New icon:
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Figure 7-53. Static/Default Routes – Add window
The following fields can be set:
Parameter
IP Address
<0.0.0.0>
Subnet Mask
<0.0.0.0>
Gateway IP
<0.0.0.0>
Metric <1 >
Description
Allows the entry of an IP address that will be a static entry into the switch’s Routing Table.
Allows the entry of a subnet mask corresponding to the IP address above.
Allows the entry of an IP address of a gateway for the IP address above.
Allows the entry of a routing protocol metric representing the number of routers between the switch and the
IP address above.
Static ARP
To make a static ARP entry:
Click the Static ARP link on the IP Forwarding menu (under Configuration − Forwarding):
Figure 7-54. Static ARP window
To delete an existing static ARP entry, click the Delete icon corresponding to the entry you want to delete.
To add a new static ARP entry, click the New icon:
Figure 7-55. Static ARP – Add window
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The following fields can be set:
Parameter
Interface Name
IP Address
MAC Address
Description
The name of the IP interface the ARP entry resides on.
The IP address of the ARP entry.
The MAC address of the ARP entry.
Spanning Tree
STP Switch Settings
To globally configure STP on the switch, select Spanning Tree Protocol on the Configuration menu and then click STP Switch Settings.
Figure 7-56. STP Switch Settings window
The Spanning Tree Protocol (STP) operates on two levels: on the switch level, the settings are globally implemented. On the port level, the settings are implemented on a per user-defined Group basis.
The factory default setting should cover the majority of installations. It is advisable to keep the default settings as set at the factory unless it is absolutely necessary to change them.
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The following fields can be set:
Parameter Description
Spanning Tree
Protocol <Enabled>
This field can be toggled between Enabled and Disabled using the pull-down menu. This will enable or disable the
Spanning Tree Protocol (STP), globally, for the switch.
Max Age: (6 .. 40
sec) <20 >
The Max. Age can be set from 6 to 40 seconds. At the end of the Max. Age, if a BPDU has still not been received from the Root Bridge, your Switch will start sending its own
BPDU to all other Switches for permission to become the
Root Bridge. If it turns out that your Switch has the lowest
Bridge Identifier, it will become the Root Bridge.
Hello Time: (1 .. 10
sec) < 2 >
The Hello Time can be set from 1 to 10 seconds. This is the interval between two transmissions of BPDU packets sent by the Root Bridge to tell all other Switches that it is indeed the Root Bridge.
Forward Delay: (4
.. 30 sec) <15 >
The Forward Delay can be from 4 to 30 seconds. This is the time any port on the Switch spends in the listening state while moving from the blocking state to the forwarding state.
Bridge Priority: (0
.. 65535) <32768>
A Priority for the switch can be set from 0 to 65535. This number is used in the voting process between switches on the network to determine which switch will be the root switch. A low number indicates a high priority, and a high probability that this switch will be elected as the root switch.
The Hello Time cannot be longer than the Max. Age. Otherwise, a configuration error will occur.
Observe the following formulas when setting the above parameters:
Max. Age ≤ 2 x (Forward Delay - 1 second)
Max. Age ≥ 2 x (Hello Time + 1 second)
Configure STP Groups
To define which ports will be members of an STP Group, highlight Group Create/Delete and press
Enter.
Figure 7-57. Spanning Tree Groups window
To delete an existing spanning tree group, click the X icon in the Delete column corresponding to the entry you want to delete.
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To add a new spanning tree group, click the New icon:
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Figure 7-58. STP Group Settings − Add window
The new spanning tree group will be identified by the name entered in the Group Name field. The group member ports will be identified by the dots in the click-boxes below the port numbers.
To edit an existing spanning tree entry, click the Hand icon:
Figure 7-59. STP Group Settings − Edit window
To view the STP Port Settings table:
Click the STP Port Settings link on the Spanning Tree Protocol menu:
Figure 7-60. STP Port Settings window
In addition to setting Spanning Tree parameters for use on the switch level, the DES-3326 allows for the configuration of groups of ports, each port-group of which will have its own spanning tree, and will require some of its own configuration settings. An STP Group will use the switch-level parameters entered above, with the addition of Port Priority and Port Cost.
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An STP Group spanning tree works in the same way as the switch-level spanning tree, but the root bridge concept is replaced with a root port concept. A root port is a port of the group that is elected on the basis of port priority and port cost, to be the connection to the network for the group. Redundant links will be blocked, just as redundant links are blocked on the switch level.
The STP on the switch level blocks redundant links between switches (and similar network devices).
The port level STP will block redundant links within an STP Group.
It is advisable to define an STP Group to correspond to a VLAN group of ports.
The following fields can be set:
Parameter Description
Cost
Priority
A Port Cost can be set from 1 to
65535. The lower the number, the greater the probability the port will be chosen to forward packets.
A Port Priority can be from 0 to 255.
The lower the number, the greater the probability the port will be chosen as the Root Port.
Link Aggregation
To configure a link aggregation group:
Click the Link Aggregation link on the Configuration menu:
Figure 7-61. Link Aggregation window
Link aggregation allows several ports to be grouped together and to act as a single link. This gives a bandwidth that is a multiple of a single link’s bandwidth.
Link aggregation is most commonly used to link a bandwidth intensive network device or devices – such as a server – to the backbone of a network.
The DES-3326 allows the creation of up to 6 link aggregation groups, each group consisting of up of up to 8 links (ports). The aggregated links must be contiguous (they must have sequential port numbers) except the two (optional) Gigabit ports – which can only belong to a single link aggregation group. A link
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Further, the aggregated links must all be of the same speed and should be configured as full duplex.
The configuration of the lowest numbered port in the group becomes the configuration for all of the ports in the aggregation group. This port is called the Master Port of the group, and all configuration options – including the VLAN configuration – that can be applied to the Master Port are applied to the entire link aggregation group.
Load balancing is automatically applied to the ports in the aggregated group, and a link failure within the group causes the network traffic to be directed to the remaining links in the group.
The Spanning Tree Protocol will treat a link aggregation group as a single link, on the switch level. On the port level, the STP will use the port parameters of the Master Port in the calculation of port cost and in determining the state of the link aggregation group. If two redundant link aggregation groups are configured on the switch, STP will block one entire group – in the same way STP will block a single port that has a redundant link.
The following fields can be set:
Parameter Description
Master Port <1> The Master port of link aggregation group.
Number of
Members <2>
Allows the entry of the number of contiguous ports that will make up the link aggregation group. These ports will be in sequential order from the Master Port.
State <Disabled> This field can be toggled between
Enabled and Disabled. This is used to turn a link aggregation group on or off. This is useful for diagnostics, to quickly isolate a bandwidth intensive network device or to have an absolute backup link aggregation group that is not under automatic control.
Utilities
Layer 2 Switch Utilities
Trivial File Transfer Protocol (TFTP) services allow the switch firmware to be upgraded by transferring a new firmware file from a TFTP server to the switch. A configuration file can also be loaded into the switch from a TFTP server, switch settings can be saved to the TFTP server, and a history log can be uploaded from the switch to the TFTP server.
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Update Firmware from Server
To update the switch’s firmware:
Select Upgrade Firmware from Server on the Maintenance menu:
Figure 7-62. Upgrade Firmware from Server window
Enter the IP address of the TFTP server in the Server IP Address field.
The TFTP server must be on the same IP interface as the switch.
Enter the path and the filename to the firmware file on the TFTP server. Note that in the above example, the firmware file is in the root directory of the D drive of the TFTP server.
The TFTP server must be running TFTP server software to perform the file transfer. TFTP server software is a part of many network management software packages – such as NetSight, or can be obtained as a separate program.
Click Apply to record the IP address of the TFTP server. Use the Save Changes window to enter the address into NV-RAM.
Click Start to initiate the file transfer.
Use Configuration File on Server
To download a switch configuration file from a TFTP server:
Click the Use Configuration File on Server on the Maintenance menu:
Figure 7-63. Use Configuration File on Server window
Enter the IP address of the TFTP server and specify the location of the switch configuration file on the
TFTP server.
Click Apply to record the IP address of the TFTP server. Use Save Changes from the Maintenance menu to enter the address into NV-RAM
Click Start to initiate the file transfer.
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Save Settings To Server
To upload a settings file to the TFTP server:
Click the Save Settings To Server on the Maintenance menu:
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Figure 7-64. Save Settings To TFTP Server window
Enter the IP address of the TFTP server and the path and filename of the settings file on the TFTP server and click Apply. Highlight Start to initiate the file transfer.
Save History Log to Server
To save a History Log on a TFTP server:
Click the Save History Log to Server on the Maintenance menu:
Figure 7-65. Save Switch History To TFTP Server window
Enter the IP address of the TFTP server and the path and filename for the history log on the TFTP server. Click Apply to make the changes current. Click Start to initiate the file transfer.
Layer 3 Utilities
Layer 3 (IP Routing) switch operation mode adds BOOTP Relay and DNS Relay to the utilities available on the switch.
BOOTP/DHCP Relay
To enable and configure BOOTP or DHCP on the switch:
Click the BOOTP/DHCP Relay link on the Configuration menu:
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Figure 7-66. BOOTP/DHCP Relay window
The following fields can be set:
Parameter Description
BOOTP/DHCP
<Disabled>
This field can be toggled between Enabled and Disabled
Relay Status the BOOTP/DHCP Relay service on the switch. The default is Disabled
Count Limit [4 ]
This field allows an entry between 1 and 16 to define the maximum number of router hops BOOTP messages can be forwarded across. The default hop count is 4.
BOOTP/DHCP
Relay Time
Threshold [0 ]
Allows an entry between 0 and 65535 seconds, and defines the maximum time limit for routing a BOOTP/DHCP packet.
If a value of 0 is entered, the switch will not process the value in the seconds field of the BOOTP or DHCP packet. If a non-zero value is entered, the switch will use that value, along with the hop count to determine whether to forward a given BOOTP or DHCP packet.
To configure the BOOTP/DHCP Relay interface:
Click the BOOTP/DHCP Relay link and then the Static Setup link:
Figure 7-67. BOOTP/DHCP Relay Interface Setup window
The following fields can be set:
Parameter
Interface Name
Description
The interface name of the IP interface on which the BOOTP or DHCP
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BOOTP/DHCP
Server <0.0.0.0> servers reside on.
Allows the entry of IP addresses for up to four BOOTP or DHCP servers.
DNS Relay
To enter the IP addresses of DNS servers (for the DNS Relay service):
Select DNS Relay on the Configuration menu and then click DNS Relay:
Figure 7-68. DNS Relay Setups window
The following fields can be set:
Parameter Description
DNS Relay State This field can be toggled between
<Disabled> Disabled and Enabled using the pulldown menu, and is used to enable or disable the DNS Relay service on the switch.
Primary Name
Server <0.0.0.0>
Allows the entry of the IP address of a primary domain name server
(DNS).
Secondary Name
Server <0.0.0.0>
Allows the entry of the IP address of a secondary domain name server
(DNS).
DNSR Relay Cache
Server Status
<Disabled>
This can be toggled between Disabled and Enabled. This determines if a
DNS cache will be enabled on the switch.
DNS Relay Static This field can be toggled using the
Table Lookup
Status <Disabled> and Enabled. This determines if the static DNS table will be used or not.
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To make a static DNS table entry:
Click the Static Setup link on the DNS Relay menu:
Figure 7-69. DNS Relay Setup window
The following fields can be set:
Parameter Description
Domain Name The domain name of the static DNS table entry.
IP Address
<0.0.0.0>
The IP address of the domain name above.
Status <Enabled> This field can be toggled using the space bar between Enabled and
Disabled.
Network Monitoring
The DES-3326 provides extensive network monitoring capabilities that can be viewed from the under
Network Monitoring menu.
Network monitoring on the switch is divided into Layer 2 and Layer 3 functions, depending upon which operating mode the switch is in. Layer 2 network monitoring functions are visible on the console when the switch is in Layer 2 Only operating mode. Layer 3 network monitoring functions are added to the console when the switch is in IP Routing operating mode.
Layer 2 Network Monitoring
Layer 2 network monitoring consists of the following screens or menus:
Statistics
• Port Utilization
• Port Error
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• Port Packet Analysis
Address Table
• Browse MAC Address Sequentially (view the MAC address forwarding table)
Applications
• GVRP (view the GVRP status table)
• GMRP (view the GMRP status table)
• Browse Router Port (view the router port status table)
• IGMP Snooping
• Switch History
Port Utilization
The Port Utilization window shows the percentage of the total available bandwidth being used on the port.
To view the port utilization:
Click the Port Utilization link on the Statistics menu under Network Monitoring:
Figure 7-70. Port Utilization window
Select the desired port by clicking on the front panel display. The Update Interval field sets the interval at which the error statistics are updated.
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The following field can be set:
Parameter Description
Update Interval
<Suspend>
The time between updates received from the switch, in seconds. Suspend stops the updates.
The default is Suspend.
Port Error Statistics
The Port Error Packet Statistics window displays the packet errors that the switch can detect and displays the results on a per port basis.
To view the error statistics for a port:
Click the Port Error Packets link on the Statistics menu under Network Monitoring:
Figure 7-71. Port Error Packet Statistics window
Select the desired port by clicking on the front panel display. The Update Interval field sets the interval at which the error statistics are updated.
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The following fields from above are described in more detail:
Parameter Description
Update Interval
<Suspend>
The interval (in seconds) that the table is updated. The default is Suspend.
RX Frames
CRC Error
Received packets.
For 10 Mbps ports, the counter records CRC errors (FCS or alignment errors). For 100 Mbps ports, the counter records the sum of CRC errors and code errors (frames received with rxerror signal).
Undersize
Oversize
The total number of frames received that were less than 64 octets long (excluding framing bits, but including FCS octets) and were otherwise well formed.
The total number of frames received that were longer than
1518 octets (excluding framing bits, but including FCS octets) and were otherwise well formed.
Fragments
Jabber
Drop Pkts
TX Frames
ExDefer
The total number of frames received that were less that 64 octets in length (excluding framing bits, but including FCS octets) and had either an FCS or an alignment error.
The total number of frames received that were longer than
1518 octets (excluding framing bits, but including FCS octets), and had either an FCS or an alignment error.
The total number of events in which packets were dropped due to a lack of resources.
Transmitted packets.
CRC Error
Late Coll.
Ex. Coll.
The number of frames for which the first transmission attempt on a particular interface was delayed because the medium was busy.
For 10 Mbps ports, the counter records CRC errors (FCS or alignment errors). For 100 Mbps ports, the counter records the sum of CRC errors and code errors (frames received with rxerror signal).
Late Collisions. The number of times that a collision is detected later than 512 bit-times into the transmission of a packet.
Excessive Collisions. The number of frames for which transmission failed due to excessive collisions
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Single Coll.
Coll. transmission failed due to excessive collisions.
Single Collision Frames. The number of successfully transmitted frames for which transmission is inhibited by more than one collision.
An estimate of the total number of collisions on this network segment.
Port Packet Analysis
The Port Packet Analysis window displays the size of packets received or transmitted by a given switch port. In addition, statistics on the number and rate of unicast, multicast, and broadcast packets received by the switch are displayed.
To view an analysis of packets received or transmitted by a port:
Click the Port Packet Analysis link on the Statistics menu under Network Monitoring:
Figure 7-72. Port Packet Analysis window
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The following fields from above are described in more detail:
Parameter Description
Update Interval
<Suspend>
The interval (in seconds) that the table is updated. The default is 2 seconds.
Frames The number of packets (or frames) received or transmitted by the switch with the size, in octets, given by the column on the right.
Frames/sec
Unicast RX
The number of packets (or frames) transmitted or received, per second, by the switch.
Displays the number of unicast packets received by the switch in total number (Frames) and the rate (Frames/sec).
Multicast RX
Broadcast RX
Displays the number of multicast packets received by the switch in total number (Frames) and the rate (Frames/sec).
Displays the number of broadcast packets received by the switch in total number (Frames) and the rate (Frames/sec).
RX Bytes
RX Frames
TX Bytes
Displays the number of bytes (octets) received by the switch in total number (Total), and rate (Total/sec).
Displays the number of packets (frames) received by the switch in total number (Total), and rate (Total/sec).
Displays the number of bytes (octets) transmitted by the switch in total number (Total), and rate (Total/sec).
TX Frames Displays the number of packets (frames) transmitted by the switch in total number (Total), and rate (Total/sec).
Browse MAC Address Sequentially
This allows the switch’s dynamic MAC address forwarding table to be viewed. When the switch learns an association between a MAC address and a port number, it makes an entry into its forwarding table.
These entries are then used to forward packets through the switch.
To view the MAC address forwarding table:
Click the Browse MAC Address Sequentially link on the Address Table menu under Network
Monitoring:
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Figure 7-73. Browse Address Table – sequential window
GVRP
This allows the GVRP status for each of the switch’s ports to be viewed by VLAN. The GVRP status screen displays the ports on the switch that are currently Egress or Untagged ports.
To view the GVRP status table:
Click the GVRP link on the Applications menu:
Figure 7-74. GVRP Status window
GMRP
The Group Multicast Registration Protocol (GMRP) Status displays the status of ports that have GMRP enabled on the switch.
To view the GMRP Status table:
Click the GMRP link on the Applications menu:
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Figure 7-75. GMRP Status window
Browse Router Port
This displays which of the switch’s ports are currently configured as router ports. A router port configured by a user (using the console or Web-based management interfaces) is displayed as a static router port, designated by S. A router port that is dynamically configured by the switch is designated by
D.
To view the Router Port table:
Click the Browse Router Port link on the Applications menu:
Figure 7-76. Browse Router Port window
S signifies a static router port, configured by the user.
D signifies a dynamically assigned router port, configured by the switch.
IGMP Snooping
This allows the switch’s IGMP Snooping table to be viewed. IGMP Snooping allows the switch to read the Multicast Group IP address and the corresponding MAC address from IGMP packets that pass through the switch. The ports where the IGMP packets were snooped are displayed, signified with an M.
The number of IGMP reports that were snooped is also displayed in the Reports field.
To view the IGMP Snooping table:
Click the IGMP Snooping Status link on the Applications menu:
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Figure 7-77. IGMP Snooping Table window
Switch History
This allows the Switch History Log to be viewed. The switch records all traps, in sequence, that identify events on the switch. The time since the last cold start of the switch is also recorded.
To view the switch history log:
Click the Switch History link on the Applications menu:
Figure 7-78. Switch History window
Layer 3 Network Monitoring
When the switch is in Layer 3 (IP Routing) mode, several items are added to the Network Monitoring menu.
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The following items are added to the Network Monitoring menu when the switch is in Layer 3
(IP Routing) mode:
Address Table
• Browse IP Address Sequentially
• Routing Table
• ARP Table
• Default IP Table
• OSPF LSDB Table
• OSPF External LSDB Table
Applications
• IP Multicast Forwarding Table
• IGMP Group Table
• DVMRP Routing Table
Browse the Routing Table
To view the contents of the IP Routing table:
Click the Routing Table link on the Address Table on Networking Monitor:
Figure 7-79. Browse Routing Table
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The following fields are displayed:
Parameter Description
IP address of a learned or statically entered destination. Destination
Address
Mask
Gateway
Jump
Interface Name
Hops
Protocol
Displays the subnet mask corresponding to the above destination IP address.
Displays the default or next hop gateway to reach the destination.
Click this button to go to a particular combination of destination IP address, subnet mask, and gateway address.
Displays the IP interface name the destination resides on.
Displays the number of hops (routers) between the switch and the destination.
Displays the routing protocol in use by the link to the destination.
ARP Table
To view the ARP table:
Click the ARP Table link on the Address Table on Networking Monitor:
Figure 7-80. ARP Table window
Default IP Address Table
To view the Default IP Address Table:
Click the Default IP Address link on the Address Table menu under Networking Monitoring:
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Figure 7-81. Default IP Address window
OSPF Link State Database Table
The switch maintains two OSPF Link State Databases (LSDB) − Internal and External. The Internal
LSDB describes the Link State Advertisements (LSA) for OSPF Antonymous Systems (AS). The External
LSDB describes the LSAa for those ASs not belonging to OSPF.
The internal OSPF Link State Database (LSDB) table can be viewed using the Web-based manager.
Figure 7-82. OSPF LSDB Table window
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The following fields can be set or are displayed:
Parameter Description
Area ID
Advertise
Router ID
Displays the OSPF Area ID.
Displays the Advertising Router’s ID.
LSDB Type Displays which one of four types of link advertisements by which the current link was discovered by the switch − Router link (RTRLink),
Network link (NETLink), Summary link (Summary), Autonomous System link (ASSummary), or ALL.
Link State ID This field identifies the portion of the internet environment that is being described by the advertisement. The contents of this field depend on the advertisement's LS type.
LS Type Link State ID
_________________________________________
1 The originating router’s Router ID.
2 The IP interface address of the network’s Designated Router.
3 The destination network’s IP address.
Mask
Cost
Sequence
4 The Router ID of the described AS boundary router.
5 The destination network’s IP address.
Displays the network mask in hexadecimal format. For example,
255.0.0.0 is displayed as FF000000.
Displays the routing metric associated with the link.
Displays a sequence number corresponding to number of times the current link has been advertised as changed.
OSPF External LSDB Table
The external OSPF Link State Database (LSDB) table can be viewed by highlighting OSPF External
LSDB Table and pressing Enter.
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Figure 7-83. OSPF External LSDB Table window
The following fields can be set or are displayed:
Parameter Description
Adv Router
ID
Displays the Advertising Router’s ID.
Link State
ID
This field identifies the portion of the internet environment that is being described by the advertisement. The contents of this field depend on the advertisement's LS type.
LS Type Link State ID
______________________________________________
1 The originating router's Router ID.
2 The IP interface address of the network's
Designated Router.
3 The destination network's IP address.
4 The Router ID of the described AS boundary router.
Mask
Cost
Sequence
Displays the network mask in hexadecimal format. For example,
255.0.0.0 is displayed as FF000000.
Displays the routing metric associated with the link.
Displays a sequence number corresponding to number of times the current link has been advertised as changed.
IP Multicast Forwarding Table
To view the IP multicast forwarding table:
Click the IP Multicast Forwarding Table link on the Applications menu under Network Monitoring:
Figure 7-84. IP Multicast Forwarding Table window
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IGMP Group Table
To view the IGMP Group table:
Click the IGMP Group Table link:
Figure 7-85. IGMP Group Table window
To display a particular multicast group, enter either the IP address in the Interface Name field, enter the multicast group IP address in the Multicast Group field, highlight GO, and press Enter.
DVMRP Routing Table
To view the DVMRP Routing table:
Click the DVMRP Routing Table link on the Applications menu under Network Monitoring:
Figure 7-86. DVMRP Routing Table window
The Source Address and Source Mask fields allow the entry of an IP address and corresponding subnet mask to search the table for. Click Jump and the DVMRP Routing table will be searched for the
IP address and subnet mask above.
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A
T
ECHNICAL
S
PECIFICATIONS
General
Protocols:
Data Transfer
Rates:
Ethernet
Fast Ethernet
Gigabit Ethernet
Topology:
IEEE 802.3u 100BASE-TX Fast Ethernet
IEEE 802.3z 1000BASE-SX Gigabit Ethernet
IEEE 802.1 P/Q VLAN
IEEE 802.3x Full-duplex Flow Control
ANSI/IEEE 802.3 Nway auto-negotiation
CSMA/CD
Half-duplex Full-duplex
10 Mbps 20Mbps
100Mbps 200Mbps n/a 2000Mbps
Star
Network Cables:
10BASE-T:
100BASE-TX:
Fiber Optic:
Number of Ports:
General
2-pair UTP Cat. 3,4,5 (100 m)
EIA/TIA- 568 100-ohm STP (100 m)
2-pair UTP Cat. 5 (100 m)
EIA/TIA-568 100-ohm STP (100 m)
IEC 793-2:1992
Type A1a - 50/125um multimode
Type A1b - 62.5/125um multimode
Both types use MTRJ or SC optical connector
24 x 10/100 Mbps NWay ports
2 Gigabit Ethernet (optional)
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AC inputs:
Power
Consumption:
DC fans:
Operating
Temperature:
Storage
Temperature:
Humidity:
Dimensions:
Physical and Environmental
100 - 240 VAC, 50/60 Hz (internal universal power supply)
40 watts maximum
2 built-in 40 x 40 x10 mm fan
0 to 50 degrees Celsius
-25 to 55 degrees Celsius
Operating: 5% to 95% RH non-condensing;
Storage: 0% to 95% RH non-condensing
441 mm x 207 mm x 44 mm (1U), 19 inch rackmount width
EMI:
Safety:
FCC Class A, CE Class A, VCCI Class A, BSMI
Class A, C-Tick Class A
FCC Part 15/IECES-003 (Canada), VCCI Class
A ITE, EN55022/EN50082-1 or EN%%o24, C-
Tick (AS/NZS3548, BSMI (CNS 13438)
UL, CSA, CE Mark, TUV/GS
UL 1950 & CSA22.2 No 950, IEC 950 (CB), TUV
(EN60950)
Transmission Method:
RAM Buffer:
Filtering Address
Table:
Packet Filtering/
Forwarding Rate:
MAC Address Learning:
Forwarding Table Age
Time:
Performance
Store-and-forward
16 MB per device
8K MAC address per device
Full-wire speed for all connections.
148,800 pps per port (for 100Mbps)
1,488,000 pps per port (for
1000Mbps)
Automatic update.
Max age:10–9999 seconds.
Default = 300.
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B
S
AMPLE
C
ONFIGURATION
F
ILE
This Appendix provides a sample configuration file that can be used with the Update Firmware and
Configuration Files screen in the console program.
The configuration file is a simple text file that you create. It has two functions: to point to the location of a file on a TFTP server, and to set the IP address, subnet mask and default gateway for the switch. The file being uploaded can be either new Runtime switching software, or a switch settings file which was previously saved on the TFTP server using the Save settings to TFTP Server option in the System Utilities menu. The IP address settings defined in the configuration file will override all other IP settings, even those defined in the settings file being uploaded. This enables the settings from one switch to be uploaded to another switch without their IP settings being the same (and thus coming into conflict).
Commands:
♦
Code_type
– this command tells the switch the type of file you wish to upload to the switch.
Possible Code_types are
PROM
,
RUNTIME
, or
CONFIG
. This should always be the first setting.
• PROM – PROM update file.
• RUNTIME – Switching software update file.
• CONFIG – Image file of switch settings created by the settings backup procedure.
♦
Image_file
– this command tells the switch the complete path and filename for the file to be loaded into the switch. For example, “
e:\3326\3326prom.tfp
”. Make sure double-quotes are used as in the example file below.
♦
Ip_addr
– this is the IP address that will be assigned to the switch. This command is included for downloading a configuration settings file to another switch. The IP address defined in this file will override the IP address in the configuration settings file, thus the switch you are downloading to can have a different IP address than the one that created the configuration settings file. An example
IP address is
10.12.19.102
.
♦
Subnet_mask
– this is the subnet mask that will be assigned to the switch. An example subnet mask is
255.128.0.0
.
♦
Default_gateway
– this is the default gateway IP that will be assigned to the switch. An example default Gateway IP is
10.254.254.253
.
♦ # – Remark. When placed as the first character on a line, the entire line will be ignored by the switch. This allows items to be labeled, or unused commands to remain in the file so that the syntax will not be forgotten.
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Notes about the Configuration File:
This configuration file can only contain 4 settings:
Code_type, Ip_addr, Subnet_mask
and
Default_gateway
.
Each command can only appear once in the configuration file.
If both the Firmware Update and Use Configuration file options are enabled, the Firmware Update command will take precedence and only the firmware file will be uploaded to the switch.
The Config image file, which contains all configuration settings and was created by the switch is prefixed with the version number of the runtime software to help with file management.
# Sample Config File
Code_type=PROM
Image_file="e:\3326\3326prom.tfp"
# specify IP address
Ip_addr = 10.12.19.102
# specify subnet mask
Subnet_mask = 255.0.0.0
# specify default gateway
Default_gateway = 10.1.1.254
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C
R
UNTIME
S
WITCHING
S
OFTWARE
D
EFAULT
S
ETTINGS
Load Mode
Switch Operation Mode
Configuration update
Firmware update
Configuration file name
Firmware file name
Out-of-band baud rate
RS232 mode
IP address
Subnet mask
Ethernet
Layer 2
Disable
Disable
None
None
9600
Console
10.90.90.90
255.0.0.0
Default Gateway
BootP service
TFTP server IP address
IGMP Snooping
Console time out
User name
0.0.0.0
Disable
0.0.0.0
Disable
10 min
None
Password None
Device STP Enable
Port STP
Port enable
Bridge max age
Bridge hello time
Bridge forward delay
Bridge priority
Port STP cost
Port STP priority
Enable
Enable
20 secs
2 sec
15 sec
32768
19 (Gigabit=4)
128
Forwarding table aging time 300 secs
Nway Enable
Flow control Disable
Broadcast storm rising threshold
Community string
VLAN mode
128Kpps
“public”, “private”
IEEE 802.1Q
SNMP VLAN(802.1Q)
Default port VID
Ingress rule checking
Mirror
1
1
Disable disable
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D
U
NDERSTANDING AND
T
ROUBLESHOOTING THE
S
PANNING
T
REE
P
ROTOCOL
When the spanning-tree algorithm determines a port should be transitioned to the forwarding state, the following occurs:
• The port is put into the listening state where it receives BPDUs and passes them to the switch’s
CPU. BPDU packets from the CPU are processed. If no BPDUs that suggest the port should go to the blocking state are received:
• The port waits for the expiration of the forward delay timer. It then moves to the learning state.
• In the learning state, the port learns station location information from the source address of packets and adds this information to its forwarding database.
• The expiration of forwarding delay timer moves the port to the forwarding state, where both learning and forwarding are enabled. At this point, packets are forwarded by the port.
Blocking State
A port in the blocking state does not forward packets. When the switch is booted, a BPDU is sent to each port in the switch putting these ports into the blocking state. A switch initially assumes it is the root, and then begins the exchange of BPDUs with other switches. This will determine which switch in the network is the best choice for the root switch. If there is only one switch on the network, no BPDU exchange occurs, the forward delay timer expires, and the ports move to the listening state. All STP enabled ports enter the blocking state following switch boot.
A port in the blocking state does the following:
• Discards packets received from the network segment to which it is attached.
• Discards packets sent from another port on the switch for forwarding.
• Does not add addresses to its forwarding database
• Receives BPDUs and directs them to the CPU.
• Does not transmit BPDUs received from the CPU.
• Receives and responds to network management messages.
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Listening State
The listening state is the first transition for a port from the blocking state. Listening is an opportunity for the switch to receive BPDUs that may tell the switch that the port should not continue to transition to the forwarding state, but should return to the blocking state (that is, a different port is a better choice).
There is no address learning or packet forwarding from a port in the listening state.
A port in the listening state does the following:
• Discards frames received from the network segment to which it is attached.
• Discards packets sent from another port on the switch for forwarding.
• Does not add addresses to its forwarding database
• Receives BPDUs and directs them to the CPU.
• Processes BPDUs received from the CPU.
• Receives and responds to network management messages.
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Learning State
A port in the learning state prepares to participate in frame forwarding. The port enters the learning state from the listening state.
A port in the learning state does the following:
• Discards frames received from the network segment to which it is attached.
• Discards packets sent from another port on the switch for forwarding.
• Adds addresses to its forwarding database.
• Receives BPDUs and directs them to the CPU.
• Processes and transmits BPDUs received from the CPU.
• Receives and responds to network management messages.
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Forwarding State
A port in the forwarding state forwards packets. The port enters the forwarding state from the learning state when the forward delay timer expires.
A port in the forwarding state does the following:
• Forwards packets received from the network segment to which it is attached.
• Forwards packets sent from another port on the switch for forwarding.
• Incorporates station location information into its address database.
• Receives BPDUs and directs them to the system CPU.
• Receives and responds to network management messages.
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Disabled State
A port in the disabled state does not participate in frame forwarding or STP. A port in the disabled state is virtually non-operational.
A disabled port does the following:
• Discards packets received from the network segment to which it is attached.
• Discards packets sent from another port on the switch for forwarding.
• Does not add addresses to its forwarding database.
• Receives BPDUs, but does not direct them to the system CPU.
• Does not receive BPDUs for transmission from the system CPU.
• Receives and responds to network management messages.
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Troubleshooting STP
Spanning Tree Protocol Failure
A failure in the STA generally leads to a bridging loop. A bridging loop in an STP environment comes from a port that should be in the blocking state, but is forwarding packets.
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In this example, B has been elected as the designated bridge and port 2 on C is in the blocking state.
The election of B as the designated bridge is determined by the exchange of BPDUs between B and C. B had a better BPDU than C. B continues sending BPDUs advertising its superiority over the other bridges on this LAN. Should C fail to receive these BPDUs for longer than the MAX AGE (default of 20 seconds), it could start to transition its port 2 from the blocking state to the forwarding state.
It should be noted: A port must continue to receive BPDUs advertising superior paths to remain in the blocking state.
There are a number of circumstances in which the STA can fail – mostly related to the loss of a large number of BPDUs. These situations will cause a port in the blocking state to transition to the forwarding state.
Full/Half Duplex Mismatch
A mismatch in the duplex state of two ports is a very common configuration error for a point-to-point link. If one port is configured as a full duplex, and the other port is left in auto-negotiation mode, the second port will end up in half-duplex because ports configured as half- or full-duplex do not negotiate.
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In the above example, port 1 on B is configured as a full-duplex port and port 1 on A is either configured as a half-duplex port, or left in auto-negotiation mode. Because port 1 on B is configured as a full-duplex port, it does not do the carrier sense when accessing the link. B will then start sending packets even if A is using the link. A will then detect collisions and begin to run the flow control algorithm. If there is enough traffic between B and A, all packets (including BPDUs) will be dropped. If the BPDUs sent from A to B are dropped for longer than the MAX AGE, B will lose its connection to the root (A) and will unblock its connection to C. This will lead to a data loop.
Unidirectional Link
Unidirectional links can be caused by an undetected failure in one side of a fiber cable, or a problem with a ports transceiver. Any failure that allows a link to remain up while providing one-way communication is very dangerous for STP.
In this example, port 2 on B can receive but not transmit packets. Port 2 on C should be in the blocking state, but since it can no longer receive BPDUs from port 2 on B, it will transition to the forwarding
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DES-3326 Layer 3 Fast Ethernet Switch User’s Guide state. If the failure exists at boot, STP will not converge and rebooting the bridges will have no effect.
(Note: Rebooting would help temporarily in the previous example).
This type of failure is difficult to detect because the Link-state LEDs for Ethernet links rely on the transmit side of the cable to detect a link. If a unidirectional failure on a link is suspected, it is usually required to go to the console or other management software and look at the packets received and transmitted for the port. A unidirectional port will have many packets transmitted but none received, or vice versa, for example.
Packet Corruption
Packet corruption can lead to the same type of failure. If a link is experiencing a high rate of physical errors, a large number of consecutive BPDUs can be dropped and a port in the blocking state would transition to the forwarding state. The blocking port would have to have the BPDUs dropped for 50 seconds (at the default settings) and a single BPDU would reset the timer. If the MAX AGE is set too low, this time is reduced.
Resource Errors
The DES-3326 Layer 3 switch performs its switching and routing functions primarily in hardware, using specialized ASICs. STP is implemented in software and is thus reliant upon the speed of the CPU and other factors to converge. If the CPU is over-utilized, it is possible that BPDUs may not be sent in a timely fashion. STP is generally not very CPU intensive and is given priority over other processes, so this type of error is rare.
It can be seen that very low values for the MAX AGE and the FORWARD DELAY can result in an unstable spanning tree. The loss of BPDUs can lead to data loops. The diameter of the network can also cause problems. The default values for STP give a maximum network diameter of about seven. This means that two switches in the network cannot be more than seven hops apart. Part of this diameter restriction is the BPDU age field. As BPDUs are propagated from the root bridge to the leaves of the spanning tree, each bridge increments the age field. When this field is beyond the maximum age, the packet is discarded. For large diameter networks, STP convergence can be very slow.
Identifying a Data Loop
Broadcast storms have a very similar effect on the network to data loops, but broadcast storm controls in modern switches have (along with subnetting and other network practices) have been very effective in controlling broadcast storms. The best way to determine if a data loop exists is to capture traffic on a saturated link and check if similar packets are seen multiple times.
Generally, if all the users of a given domain are having trouble connecting to the network at the same time, a data loop can be suspected. The port utilization data in the switch’s console will give unusually high values in this case.
The priority for most cases is to restore connectivity as soon as possible. The simplest remedy is to manually disable all of the ports that provide redundant links. Disabling ports one at a time, and then checking for a restoration of the user’s connectivity will identify the link that is causing the problem, if time allows. Connectivity will be restored immediately after disabling a data loop.
Avoiding Trouble
Know where the root is located.
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Although the STP can elect a root bridge, a well-designed network will have an identifiable root for each
VLAN. Careful setup of the STP parameters will lead to the selection of this best switch as the root for each VLAN. Redundant links can then be built into the network. STP is well suited to maintaining connectivity in the event of a device failure or removal, but is poorly suited to designing networks.
Know which links are redundant.
Organize the redundant links and tune the port cost parameter of STP to force those ports to be in the blocking state.
For each VLAN, know which ports should be blocking in a stable network. A network diagram that shows each physical loop in the network and which ports break which loops is extremely helpful.
Minimize the number of ports in the blocking state.
A single blocking port transitioning to the forwarding state at an inappropriate time can cause a large part of a network to fail. Limiting the number of blocked ports help to limit the risk of an inappropriate transition.
This is a common network design. The switches C and D have redundant links to the backbone switches A and B using trunks. Trunks, by default, carry all the VLAN traffic from VLAN 1 and VLAN 2.
So switch C is not only receiving traffic for VLAN 1, but it is also receiving unnecessary broadcast and multicast traffic for VLAN 2. It is also blocking one port for VLAN 2. Thus, there are three redundant paths between switches A and B and two blocked ports per VLAN. This increases the chance of a data loop.
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In this example, the VLAN definitions are extended to switches A and B. This gives only a single blocked port per VLAN and allows the removal of all redundant links by removing switch A or B from the network.
Impact of Layer 3 Switching.
The IP routing operational mode of the DES-3326 Layer 3 switch can accomplish the following:
• Building a forwarding table, and exchanging information with its peers using routing protocols.
• Receiving packets and forwarding them to the correct interface based upon their destination address
With layer 3 switching, there is no performance penalty to introducing a routing hop and creating an additional segment of the network.
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Using layer 3 switches and IP routing eliminates the need for STP port blocking because the packets are routed by destination addresses. The link redundancy remains, and relying on the routing protocols gives a faster convergence than with STP.
The drawback is that the introduction of layer 3 switching usually requires a new addressing scheme.
278
E
B
RIEF
R
EVIEW OF
B
ITWISE
L
OGICAL
O
PERATIONS
AND
The logical AND operation compares 2 bits and if they are both “ 1”, then the result is “1”, otherwise, the result is “0”.
0 1
0 0 0
1 0 1
OR
The logical OR operation compares 2 bits and if either or both bits are “1”, then the result is “1”, otherwise, the result is “0”.
0 1
0 0 1
1 1 1
XOR
The logical XOR (exclusive OR) operation compares 2 bits and if exactly one of them is a “1”, then the result is
“1”, otherwise the result is “0”.
0 1
0 0 1
1 1 0
NOT
The logical NOT operation simply changes the value of a single bit. If it is a “1”, the result is “0”, if it is a
“0”, the result is “1”. This operation is carried out on a single bit.
0 1
1 0
I
NDEX
1
1000BASE-SX Gigabit Module.....................................21
100BASE-FX Fiber (MTRJ Type) Module ...................20
100BASE-FX Fiber Module ..........................................20
100BASE-TX Device ....................................................23
100BASE-TX Module ...................................................19
10BASE-T Device .........................................................23
A
AC inputs ........................................................................259
AC power cord...............................................................15
Accessory pack ..............................................................15
Administrator .................................................................88
Aging Time, definition of ..............................................29
Aging Time, range of.....................................................29
APPLY ..........................................................................87
Auto polarity detection...................................................12
Automatic learning.........................................................29 auto-negotiate.................................................................11
B
Baud Rate.....................................................................101
BOOTP protocol ....................................................97, 196
BOOTP server........................................................97, 196
Bridge Forward Delay .................................................34
Bridge Hello Time ........................................34, 149, 235
Bridge Max. Age...........................................34, 149, 235
Bridge Priority .....................................................33, 149
Browse the Routing Table............................................252
C
Changing your Password..............................................93
Community Name ..........................................................26
Configuration .......................................................95, 194
Connecting to the Switch
VT100-compatible terminal........................................87
Connections
Switch to End Node ....................................................22
Switch to Hub or Switch.............................................22 console ...........................................................................87
Console..........................................................................21 console port..............................................................11, 18
Console port (RS-232 DCE) ..........................................24
Console port settings .....................................................24
Console Timeout..........................................................101
Create/Modify User Accounts .......................................93 crossover cable...............................................................23
D
Data filtering ..................................................................12
Data filtering rate ...........................................................12
Data forwarding .............................................................12
Data forwarding rate ......................................................12
Default Gateway ............................................97, 187, 196
Diagnostic port...............................................................11
Dimensions ......................................................................259
Dynamic filtering...........................................................29
E
Egress port....................................................................37
End Node .......................................................................22
Enterasys WebView User Interface .............................189
Ethernet protocol ...........................................................14
F factory reset ...................................................................92
Filtering..........................................................................29
Flash memory ................................................................13
Forwarding.....................................................................28
Front Panel.....................................................................18
Full-duplex.....................................................................12
G gateway router ...............................................................26
General User ..........................................................90, 185
Gigabit Ethernet.............................................................14
H half-duplex.....................................................................12
Humidity .........................................................................259
I
IEEE 802.1Q tagging.....................................................37
IEEE 802.1Q VLANs ....................................................37
Illustration of STA.........................................................34
Ingress port.............................................................37, 40
IP Address......................................................................25
IP Addresses and SNMP Community Names................25
IP Configuration ..................................................96, 194
L
LED Indicators...............................................................21 load-balancing................................................................36
log in..............................................................................92
Logging on.....................................................................87
M
MAC address filtering ...................................................29
MAC Address Learning .......................................................259
MAC-based VLANs ......................................................37
Main Menu...................................................88, 89, 91, 92
Management...................................................................13
Management Information Base (MIB)...........................28 master port .....................................................................36
Max. Age ................................................34, 149, 150, 235
MIB................................................................................28
MIB objects ...................................................................28
MIB-II............................................................................28
MIB-II (RFC 1213)........................................................13
MIBs ..............................................................................28 module .....................................................................11, 18
Modules .........................................................................19
N
Network Classes
Class A, B, C for Subnet Mask...........................97, 196
NV-RAM ...............................................................91, 186
NWay .............................................................................11
O
Operating Temperature ........................................................259
Out-of-Band/Console Setting menu.....................100, 199
P password ......................................................................187
Port Priority .........................................................34, 151 port-based VLANs .........................................................37 ports ...............................................................................11
Power.............................................................................21
Power Consumption ...........................................................259
R
RAM ......................................................................91, 186
RAM Buffer .....................................................................259
Rear Panel ................................................................18, 19
refresh ...........................................................................87
RS-232 ...........................................................................11
S
Save Changes ............................................................87
Saving Changes......................................................91, 186
Screen Hierarchy..................................................107, 190 security...........................................................................26
Setting an IP Address...................................................187
Setting the Administrator Password.............................188
Setting Trap Destinations.............................................188
Setting Up The Switch ...........................................95, 193
Setting Up Web Management ......................................187
Setup ..............................................................................15
Single Coll ...........................................................167, 246
SLIP management ................................................101, 200
Spanning Tree Algorithm...............................................13
Spanning Tree Algorithm (STA) ...................................30
Spanning Tree Protocol..................................................29
Storage Temperature ...........................................................259
Store and forward switching ..........................................12
Subnet Mask ..........................................................97, 196
Super User .............................................................90, 185
T
tagging ...........................................................................37
Tagging .........................................................................37
TCP/IP Settings......................................................96, 194 terminal emulator ...........................................................87 terminal parameters........................................................87
Third-party vendors’ SNMP software ...........................28
Transmission Methods ........................................................259
Trap managers..........................................................26, 27
Trap Type
Authentication Failure ..........................................26, 28
Broadcast Storm .........................................................28
Cold Start..............................................................26, 27
Link Change Event ...............................................26, 28
New Root....................................................................26
Port Partition...............................................................28
Topology Change .................................................26, 28
Warm Start............................................................26, 27
Traps ........................................................................26, 27 trunk group ....................................................................35
U unauthorized users .........................................................87
Unpacking......................................................................15
untagging .......................................................................37
Untagging......................................................................37
Uplink ......................................................................18, 23
User Accounts Management ..........................................93
V
View/Delete User Accounts...........................................93
VLAN ............................................................................29
VT100-compatible terminal...........................................87
W web-based management ...............................................182
Web-based management module .................................182
Weight ............................................................................259
Offices
Australasia
Unit 16, 390 Eastern Valley Way, Roseville, NSW 2069 Australia
TEL: 61-2-9417-7100 FAX: 61-2-9417-1077 TOLL FREE (Australia): 1800-177100
TOLL FREE (New Zealand): 0800-900900
URL: www.dlink.com.au E-MAIL: [email protected] & [email protected]
Level 1, 434 St. Kilda Road, Melbourne, Victoria 3004 Australia
TEL: 61-3-9281-3232 FAX: 61-3-9281-3229 MOBILE: 0412-660-064
Chile
2180 Winston Park Drive, Oakville, Ontario, L6H 5W1 Canada
TEL: 1-905-829-5033 FAX: 1-905-829-5095 BBS: 1-965-279-8732
TOLL FREE: 1-800-354-6522 URL: www.dlink.ca
FTP: ftp.dlinknet.com E-MAIL: [email protected]
D-Link South America
Isidora Goyeechea 2934 of 702, Las Condes, Santiago, Chile, S. A.
TEL: 56-2-232-3185 FAX: 56-2-232-0923 URL: www.dlink.cl
E-MAIL: [email protected] & [email protected]
China
2F, Sigma Building, 49 Zhichun Road, Haidan District, 100080 Beijing, China
TEL: 86-10-88097777 FAX: 86-10-88096789 URL: www.dlink.com.cn
E-MAIL: [email protected]
Denmark
Naverland 2, DK-2600 Glostrup, Copenhagen, Denmark
Egypt
TEL: 45-43-969040 FAX:45-43-424347 URL: www.dlink.dk E-MAIL: [email protected]
D-Link Middle East
7 Assem Ebn Sabet Street, Heliopolis, Cairo, Egypt
TEL: 20-2-635-6176 FAX: 20-2-635-6192 URL: www.dlink-me.com
E-MAIL: [email protected] & [email protected]
Finland
Thlli-ja Pakkahuone Katajanokanlaituri 5, FIN– 00160 Helsinki
TEL: 358-9-622-91660 FAX: 358-9-622-91661 URL: www.dlink-fi.com
France D-Link
Le Florilege #2, Allee de la Fresnerie, 78330 Fontenay le Fleury, France
TEL: 33-1-3023-8688 FAX: 33-1-3023-8689 URL: www.dlink-france.fr
E-MAIL:
Germany D-Link Central Europe/D-Link Deutschland GmbH
Schwalbacher Strasse 74, D-65760 Eschborn, Germany
TEL: 49-6196-77990 FAX: 49-6196-7799300 URL: www.dlink.de
BBS: 49-(0) 6192-971199 (analog) BBS: 49-(0) 6192-971198 (ISDN)
INFO: 00800-7250-0000 (toll free) HELP: 00800-7250-4000 (toll free)
REPAIR: 00800-7250-8000 E-MAIL: [email protected]
India
Plot No.5, Kurla-Bandra Complex Rd., Off Cst Rd., Santacruz (E), Bombay, 400 098 India
TEL: 91-22-652-6696 FAX: 91-22-652-8914 URL: www.dlink-india.com
E-MAIL:
Italy D-Link Mediterraneo Srl/D-Link Italia
Via Nino Bonnet n. 6/b, 20154, Milano, Italy
TEL: 39-02-2900-0676 FAX: 39-02-2900-1723 URL: www.dlink.it E-MAIL: [email protected]
10F, 8-8-15 Nishi-Gotanda, Shinagawa-ku, Tokyo 141, Japan
TEL: 81-3-5434-9678 FAX: 81-3-5434-9868 URL: www.d-link.co.jp
Benelux
Fellenoord 1305611 ZB, Eindhoven, the Netherlands
TEL: 31-40-2668713 FAX: 31-40-2668666 URL: www.d-link-benelux.nl
Russia
Waldemar Thranesgt. 77, 0175 Oslo, Norway
TEL: 47-22-991890 FAX: 47-22-207039
D-Link Russia
Michurinski Prospekt 49, 117607 Moscow, Russia
TEL: 7-095-737-3389 & 7-095-737-3492 FAX: 7-095-737-3390 URL: www.dlink.ru
E-MAIL:
Singapore D-Link International
1 International Business Park, #03-12 The Synergy, Singapore 609917
TEL: 65-774-6233 FAX: 65-774-6322 E-MAIL: [email protected] www.dlink-intl.com
South Africa D-Link South Africa
102 – 106 Witchhazel Avenue, Einstein Park 2, Block B, Highveld Technopark,
Centurion, South Africa
TEL: 27 (0) 12-665-2165 FAX: 27 (0) 12-665-2186 URL: www.d-link.co.za [email protected]
C/Sabino De Arana, 56 Bajos, 08028 Barcelona, Spain
TEL: 34 93 4090770 FAX: 34 93 4910795 URL: www.dlinkiberia.es
E-MAIL: [email protected]
Sweden
P. O. Box 15036, S-167 15 Bromma, Sweden
TEL: 46-(0) 8-564-61900 FAX: 46-(0) 8-564-61901 E-MAIL: [email protected]
URL:
Turkey
U.A.E.
2F, No. 119 Pao-Chung Rd, Hsin-Tien, Taipei, Taiwan
TEL: 886-2-2910-2626 FAX: 886-2-2910-1515 URL: www.dlinktw.com.tw
E-MAIL: [email protected]
D-Link Middle East
Deniz Bilgisayar, Buyukdere Cad. Naci Kasim Sk., No. 5 Mecidiyekoy, Istanbul, Turkey
TEL: 90-212-213-3400 FAX: 90-212-213-3420 E-MAIL: [email protected]
D-Link Middle East
CHS Aptec (Dubai), P.O. Box 33550 Dubai U.A.E.
TEL: 971-4-366-885 FAX: 971-4-355-941 E-MAIL: [email protected]
4 th Floor, Merit House, Edgware Road, Colindale, London NW9 5AB United Kingdom
TEL: 44 (0) 20-8731-5555 FAX: 44 (0) 20-8731-5511 BBS: 44 (0) 181-235-5511
URL: www.dlink.co.uk E-MAIL: [email protected]
U.S.A.
53 Discovery Drive, Irvine, CA 92618, USA
TEL: 1-949-788-0805 FAX: 1-949-753-7033 BBS: 1-949-455-1779 & 1-949-455-9616
INFO: 1-800-326-1688 URL: www.dlink.com
E-MAIL:
Registration Card
Print, type or use block letters.
Your name: Mr./Ms_____________________________________________________________________________
Organization: ________________________________________________ Dept. ____________________________
Your title at organization: ________________________________________________________________________
Telephone: _______________________________________ Fax:________________________________________
Organization's full address: ______________________________________________________________________
____________________________________________________________________________________________
Country: _____________________________________________________________________________________
Date of purchase (Month/Day/Year): _______________________________________________________________
Product Model Product Serial
No.
(* Applies to adapters only)
* Product installed in type of computer (e.g., Compaq 486)
* Product installed in computer serial No.
Product was purchased from:
Reseller's name: ______________________________________________________________________________
Telephone: _______________________________________ Fax:________________________________________
Reseller's full address: _________________________________________________________________________
_________________________________________________________________________
_________________________________________________________________________
Answers to the following questions help us to support your product:
1. Where and how will the product primarily be used?
Home Office Travel Company Business Home Business Personal Use
2. How many employees work at installation site?
1 employee 2-9 10-49 50-99 100-499 500-999 1000 or more
3. What network protocol(s) does your organization use ?
XNS/IPX TCP/IP DECnet Others_____________________________
4. What network operating system(s) does your organization use ?
D-Link LANsmart Novell NetWare NetWare Lite SCO Unix/Xenix PC NFS 3Com 3+Open
Banyan Vines DECnet Pathwork Windows NT Windows NTAS Windows '95
Others__________________________________________
5. What network management program does your organization use ?
D-View HP OpenView/Windows HP OpenView/Unix SunNet Manager Novell NMS
NetView 6000 Others________________________________________
6. What network medium/media does your organization use ?
Fiber-optics Thick coax Ethernet Thin coax Ethernet 10BASE-T UTP/STP
100BASE-TX 100BASE-T4 100VGAnyLAN Others_________________
7. What applications are used on your network?
Desktop publishing Spreadsheet Word processing CAD/CAM
Database management Accounting Others_____________________
8. What category best describes your company?
Aerospace Engineering Education Finance Hospital Legal Insurance/Real Estate Manufacturing
Retail/Chainstore/Wholesale Government Transportation/Utilities/Communication VAR
System house/company Other________________________________
9. Would you recommend your D-Link product to a friend?
Yes No Don't know yet
10.Your comments on this product?
__________________________________________________________________________________________
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