M20 Internet Backbone Router
Fan tray
assemblies (3)
Cable management system
Routing
Engines
Rear Routing
Engine panel
SSB0
SSB1
Craft
interface
FPC0
1112
FPC1
FPC2
1111
PICs
(on FPCs)
FPC3
Cable
management
system
Power
supplies
Front View
Rear View
M20 Router Major Hardware Components
Component
Flexible PIC
Concentrators (FPCs)
Physical Interface Cards
(PICs)
System and Switch
Boards (SSBs)
Routing Engine
Power supplies
Cooling system
Craft interface
Quantity
1–4
1–4 per FPC
1–2
1–2
2 AC or
2 DC
3 fan trays and
1 rear Routing
Engine fan
1
Function
Connects PICs to router components,
houses shared memory
Provides interfaces to various network media
Redundant
–
–
Performs route lookups, manages shared memory, –
transfers control packets
Handles routing protocols, maintains
–
routing tables
Distributes voltages to components
Yes
Cools router components
Yes
Displays status and allows you to perform
control functions
–
Field-replaceable
Hot-removable
Hot-insertable
From removed
FPC
Hot-pluggable
Offline
Button
Yes
Yes
–
Hot-pluggable
Yes
Hot-removable
Hot-insertable
Hot-removable
Hot-insertable
–
Hot-removable
Hot-insertable
–
–
Hot-removable and hot-insertable—Can remove and replace without powering down the router or disrupting routing functions.
Hot-pluggable—Can remove without powering down the router, but forwarding is interrupted, or router switches to warm shutdown mode,
until replacement is installed.
M 2 0 R o u t e r P h ys i c a l S p e c i f i c a t i o n s
Dimensions
Weight
Required clearances
Hardware
14 in. (36 cm) high x 19 in. (48.3) wide x 21 in. (54 cm) deep
80 lb (36 kg) minimum configuration
134 lb (61 kg) maximum configuration
19 in. (48 cm) front and rear; 6 in. (15.2 cm) each side
JUNOS Release 4.3
M20 Internet Backbone Router
M20 Router Power Supply Specifications
Specification
Maximum power consumption
Input voltage
Input line frequency
Input current rating
Output voltages
Power and grounding cords and cables
AC
750 W
90 through 264 VAC operating range
47–63 Hz, autoranging
13 A @ 90 V
+3.3 V; +5 V; +2.5 V; +12 V; +24 V
Country-specific; see M20 Internet Backbone
Router Hardware Installation Guide
DC
750 W
–40 through –72 VDC operating range
–
24 A @ –48 V (typical)
+3.3 V; +5 V; +2.5 V; +12 V; +24 V
4 or 6 AWG wire cables with dual hole
1/4 –20 UNC terminal studs @ 15.86 mm
(0.625 in.) centers
M20 Router LEDs
Component
FPCs
PICs
SSBs
Routing Engine
Power supplies
Alarm LEDs
Red alarm
Yellow alarm
LED
Green OK
Amber FAIL
1 LED per port, with 4 states: Red, Green, Amber, Off
Blue MASTER
Green ONLINE
Amber OFFLINE
2 Green STATUS
Blue MASTER
Green ONLINE
Amber OFFLINE
Green OK
Red FAIL
Large circular red
Large triangular amber
Location
Craft interface
PIC faceplate
SSB faceplate
Craft interface and
Routing Engine panel
Power supply faceplate
Craft interface
Craft interface
Ta k i n g C o m p o n e n t s O f f l i n e
Component
FPC
PIC
SSB
Routing Engine
Procedure
1. Press the FPC offline button, located on the right side of the craft interface, for the appropriate FPC.
2. Press and hold the button until the amber FAIL LED lights (about 5 seconds).
Remove the FPC containing the PIC (this will take all interfaces on the removed FPC offline).
1. Press the SSB offline button on the SSB faceplate.
2. Press and hold the button until the amber SSB OFFLINE LED lights (about 5 seconds).
1. Press the Routing Engine (RE0 or RE1) offline button on the craft interface or on the Routing Engine panel.
2. Press and hold the button until the amber OFFLINE LED lights.
You can take the backup Routing Engine offline without interrupting the functioning of the router. If you take the master
Routing Engine offline, the router reboots with the other Routing Engine functioning as master. The routing and forwarding
functions are interrupted during this process.
M20 Internet Backbone Router
System Architecture
Routing Engine
The router has two major architectural components: the Routing
Engine, which provides Layer 3 routing services and network
management; and the Packet Forwarding Engine, which provides
packet switching, route lookups, and packet forwarding. The
Routing Engine and Packet Forwarding Engine operate
independently, but constantly communicate through a 100-Mbps
link, as illustrated in the figure at the right.
Packets
in
Packet Forwarding
Engine
PIC
Packet Flow through the
Packet Forwarding Engine
To ensure efficient packet flow through
the system, data packet forwarding is
handled by ASICs on the hardware
components. The figure at the right
shows the sequence of packet flow
through the Packet Forwarding Engine.
PIC
Controller
Controller
SSB
FPC
FPC
Internet
processor
Packet
in
Packets
out
1244
100-Mbps link
I/O
manager
Distributed Buffer
Manager
I/O
manager
Packet
out
= ASIC
Midplane
Routing Engine Architecture
The Routing Engine handles all the routing protocol
processes as well as processes controlling
interfaces, router components, system
management, and user access. These processes run
on top of a kernel that interacts with the Packet
Forwarding Engine.
JUNOS
software
System
management
processes
Routing
protocols
Kernel
1243
Routing Engine
Control
functions
System processes
Operating system
1164
Intel-based PCI platform
Routing protocol
process
Control Packet Handling
Forwarding table
updates
Routing Engine
Routing protocol
packets from network
Forwarding table
Packets
in
Packet Forwarding
Engine
Packets
out
1240
The Routing Engine constructs and maintains routing
tables, and derives a table of active routes, called the
forwarding table, from the routing tables. The forwarding
table is then copied into the Packet Forwarding Engine.
M20 Internet Backbone Router
General Safety Guidelines
■
Only trained and qualified personnel should install or replace the router.
■
Perform only the procedures described in the M20 Internet Backbone Router Hardware Installation Guide.
Other services should be performed by authorized service personnel only.
■
For protection against shock hazard, verify that all power cables are disconnected before servicing the
router.
■
Before installing the router, read the guidelines in the “Prepare the Site” section of the M20 Internet
Backbone Router Hardware Installation Guide to make sure that the site meets power, environmental, and
clearance requirements for the router.
■
Manually installing the router requires two people to lift the chassis and a third person to secure the
mounting screws. Before lifting the chassis, and remove components as described in the M20 Internet
Backbone Router Hardware Installation Guide. To prevent injury, keep your back straight and lift with your legs,
not your back. Do not attempt to lift the chassis with the handles on the power supplies.
■
Do not work on the router or connect or disconnect cables during electrical storms.
■
Never install electrical jacks in wet locations unless the jacks are specifically designed for wet environments.
■
Operate the router only when the grounding wire is connected.
■
Use copper conductors only.
■
Avoid touching uninsulated electrical wires or terminals that have not been disconnected from their power
source. Doing so could cause electrical shock.
■
Do not open or remove chassis covers or sheet metal parts when instructions are not provided in the
M20 Internet Backbone Router Hardware Installation Guide. Doing so could cause severe electrical shock.
■
Do not push or force any objects through any of the openings in the chassis frame. Doing so could result in
electrical shock or fire.
■
Avoid spilling liquid into the router chassis or onto any router components. Doing so could cause electrical
shock or damage the router.
■
Before working on equipment that is connected to power lines, remove jewelry, including rings, necklaces,
and watches. Metal objects heat up when connected to power and ground and can cause serious burns or
weld the metal object to the terminals.
■
Failure to observe these safety warnings could result in serious physical injury.
Agency Approvals
Category
Safety
EMI
Immunity
NEBS
ETSI
Approval
CSA C22.2 No. 950
■ UL 1950
■ EN 60950, Safety of Information Technology Equipment
■ EN 60825-1 Safety of Laser Products–Part 1: Equipment Classification, Requirements and User’s Guide
■ EN 60825-2 Safety of Laser Products–Part 2: Safety of Optical Fibre Communication Systems
■ AS 3548 Class A (Australia)
■ EN 55022 Class A emissions (Europe)
■ FCC Class A (USA)
■ VCCI Class A (Japan)
■ EN 61000-3-2 Power Line Harmonics
■ EN 61000-4-2 ESD
■ EN 61000-4-3 Radiated Immunity
■ EN 61000-4-4 EFT
■ EN 61000-4-5 Surge
■ EN 61000-4-6 Low Frequency Common Immunity
■ EN 61000-4-11 Voltage Dips and Sags
The router has been tested to meet the following standards:
■ GR-63-Core: NEBS, Physical Protection
■ GR-1089-Core: EMC and Electrical Safety for Network Telecommunications Equipment
■ SR-3580 NEBS Criteria Levels (Level 3 Compliance)
■ ETS-300386-2 Switching Equipment
■
w w w. j u n i p e r. n e t
For support issues, contact the Juniper Networks Technical Assistance Center (JTAC) at 1-888-314-JTAC
(within the United States) or 408-745-2121 (from outside the United States). For other contact
information, refer to www.juniper.net/contactus.html.
Juniper Networks is a registered trademark of Juniper Networks, Inc. Internet Processor, Internet Processor II, JUNOS, JUNOScript, M5, M10, M20, M40, and
M160 are trademarks of Juniper Networks, Inc. All other trademarks, service marks, registered trademarks, or registered service marks may be the property of
their respective owners. All specifications are subject to change without notice. Copyright © 2001, Juniper Networks, Inc. All rights reserved. Printed in USA.
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