QoS: Latency and Jitter Configuration Guide, Cisco IOS Release 12.4T Americas Headquarters

QoS: Latency and Jitter Configuration Guide, Cisco IOS Release 12.4T Americas Headquarters
QoS: Latency and Jitter Configuration
Guide, Cisco IOS Release 12.4T
Americas Headquarters
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CONTENTS
Link Efficiency Mechanisms Overview 1
Finding Feature Information 1
Multilink PPP 1
Frame Relay Fragmentation 1
Header Compression 2
Reducing Latency and Jitter for Real-Time Traffic Using Multilink PPP 3
Finding Feature Information 3
Information About Multilink 3
Restrictions for Multilink 3
Multilink Functionality 4
Multilink Interleaving 4
Multilink Fragmentation 4
Multilink Resequencing 5
Multilink Bundles and Their Network Links 6
Multiclass Multilink PPP 6
Distributed Multilink PPP 6
Where to Go Next 7
Additional References 7
Using Multilink PPP over ATM Links 11
Finding Feature Information 11
Prerequisites for Using Multilink PPP over ATM Links 11
Restrictions for Using Multilink PPP over ATM Links 11
Information About Using Multilink PPP over ATM Links 12
MQC and Multilink PPP over ATM Links 12
VirtualTemplateInterfaces 12
Multilink Group Interfaces 12
How to Configure Multilink PPP over ATM Links 12
Configuring Multilink PPP over ATM Links on a Virtual Template Interface 12
Configuring Multilink PPP over ATM Links on a Multilink Group Interface 15
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Contents
What to Do Next 17
Associating the Virtual Template Interface with the Multilink Group 17
Associating the Virtual Template Interface with an ATM PVC 18
Verifying the Multilink PPP over ATM Links Configuration 20
Configuration Examples for Using Multilink PPP over ATM Links 21
Example Configuring Multilink PPP over ATM Links on a Virtual Template Interface 22
Example Configuring Multilink PPP over ATM Links on a Multilink Group Interface 23
Example Associating the Virtual Template Interface with the Multilink Group 23
Example Associating the Virtual Template Interface with an ATM PVC 24
Example Verifying the Multilink PPP over ATM Links Configuration 24
Where to Go Next 24
Additional References 24
Feature Information for Using Multilink PPP over ATM Links 26
Using Multilink PPP over Dialer Interface Links 29
Finding Feature Information 29
Prerequisites for Using Multilink PPP over Dialer Interface Links 29
Restrictions for Using Multilink PPP over Dialer Interface Links 30
Information About Using Multilink PPP over Dialer Interface Links 30
Dialer Profiles 30
MQC and Multilink PPP over Dialer Interface Links 30
How to Configure Multilink PPP over Dialer Interface Links 31
Configuring Multilink PPP over Dialer Interface Links 31
Associating the Dialer Interface with a BRI 34
Verifying the Multilink PPP over Dialer Interface Link Configuration 36
Configuration Examples for Using Multilink PPP over Dialer Interface Links 36
Example Configuring Multilink PPP over Dialer Interface Links 37
Example Associating the Dialer Interface with a BRI 37
Example Verifying the Multilink PPP over Dialer Interface Link Configuration 38
Where to Go Next 38
Additional References 38
Feature Information for Using Multilink PPP over Dialer Interface Links 40
Using Multilink PPP over Frame Relay 43
Finding Feature Information 43
Prerequisites for Using Multilink PPP over Frame Relay 43
Restrictions for Using Multilink PPP over Frame Relay 44
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Contents
Information About Using Multilink PPP over Frame Relay 44
Frame Relay Traffic Shaping and Multilink PPP over Frame Relay 44
MQC and Multilink PPP over Frame Relay 45
Virtual Template Interfaces 45
Multilink Group Interfaces 45
How to Configure Multilink PPP over Frame Relay 45
Configuring Multilink PPP over Frame Relay on a Virtual Template Interface 45
Configuring Multilink PPP over Frame Relay on a Multilink Group Interface 48
What to Do Next 49
Associating the Virtual Template Interface with the Multilink Group 50
Associating the Virtual Template Interface with a Frame Relay PVC 51
Verifying the Multilink PPP over Frame Relay Configuration 53
Configuration Examples for Multilink PPP over Frame Relay 54
Example Configuring Multilink PPP over Frame Relay on a Virtual Template Interface 54
Example Configuring Multilink PPP over Frame Relay on a Multilink Group Interface 55
Example Associating the Virtual Template Interface with the Multilink Group 55
Example Associating the Virtual Template Interface with a Frame Relay PVC 56
Example Verifying the Multilink PPP over Frame Relay Configuration 56
Where to Go Next 56
Additional References 57
Feature Information for Using Multilink PPP over Frame Relay 58
Using Multilink PPP over Serial Interface Links 61
Finding Feature Information 61
Prerequisites for Using Multilink PPP over Serial Interface Links 61
Restrictions for Using Multilink PPP over Serial Interface Links 62
Information About Using Multilink PPP over Serial Interface Links 62
MQC and Multilink PPP over Serial Interface Links 62
Multilink Group Interfaces 63
How to Configure Multilink PPP over Serial Interface Links 63
Configuring Multilink PPP over Serial Interface Links on a Multilink Group Interface 63
Associating the Serial Interface with the Multilink Group 65
Verifying the Multilink PPP over Serial Interface Link Configuration 67
Configuration Examples for Using Multilink PPP over Serial Interface Links 68
Configuring Multilink PPP over Serial Interface Links on a Multilink Group Interface Example 68
Associating the Serial Interface with the Multilink Group Example 69
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Contents
Verifying the Multilink PPP over Serial Interface Link Configuration Example 69
Where to Go Next 70
Additional References 70
Feature Information for Using Multilink PPP over Serial Interface Links 71
QoS: Latency and Jitter Configuration Guide, Cisco IOS Release 12.4T
vi
Link Efficiency Mechanisms Overview
Cisco IOS software offers a number of link-layer efficiency mechanisms or features (listed below)
designed to reduce latency and jitter for network traffic. These mechanisms work with queuing and
fragmentation to improve the efficiency and predictability of the application service levels.
This chapter gives a brief introduction to these link-layer efficiency mechanisms described in the
following sections:
•
•
•
•
Finding Feature Information, page 1
Multilink PPP, page 1
Frame Relay Fragmentation, page 1
Header Compression, page 2
Finding Feature Information
Your software release may not support all the features documented in this module. For the latest feature
information and caveats, see the release notes for your platform and software release. To find information
about the features documented in this module, and to see a list of the releases in which each feature is
supported, see the Feature Information Table at the end of this document.
Use Cisco Feature Navigator to find information about platform support and Cisco software image support.
To access Cisco Feature Navigator, go to www.cisco.com/go/cfn. An account on Cisco.com is not required.
Multilink PPP
At the top level, Multilink PPP (also known as MLP or simply Multilink) provides packet interleaving,
packet fragmentation, and packet resequencing across multiple logical data links. The packet interleaving,
packet fragmentation, and packet resequencing are used to accommodate the fast transmission times
required for sending real-time packets (for example, voice packets) across the network links. Multilink is
especially useful over slow network links (that is, a network link with a link speed less than or equal to 768
kbps).
For more information about the functionality of Multilink when providing quality of service (QoS) on your
network, see the "Reducing Latency and Jitter for Real-Time Traffic Using Multilink PPP" module.
Frame Relay Fragmentation
Cisco has developed the following three methods of performing Frame Relay fragmentation:
•
End-to-end FRF.12 (and higher) fragmentation
QoS: Latency and Jitter Configuration Guide, Cisco IOS Release 12.4T
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Link Efficiency Mechanisms Overview
Header Compression
•
•
Frame Relay fragmentation using FRF.11 Annex C (and higher)
Cisco proprietary encapsulation
For more information about Frame Relay fragmentation, see the " Frame Relay Queueing and
Fragmentation at the Interface" module.
Header Compression
Header compression is a mechanism that compresses the IP header in a packet before the packet is
transmitted. Header compression reduces network overhead and speeds up the transmission of Real-Time
Transport Protocol (RTP) and Transmission Control Protocol (TCP) packets. Header compression also
reduces the amount of bandwidth consumed when the RTP or TCP packets are transmitted.
Cisco provides two basic types of header compression: RTP header compression (used for RTP packets)
and TCP header compression (used for TCP packets).
For more information about header compression, see the "Header Compression" module.
Cisco and the Cisco logo are trademarks or registered trademarks of Cisco and/or its affiliates in the U.S.
and other countries. To view a list of Cisco trademarks, go to this URL: www.cisco.com/go/trademarks.
Third-party trademarks mentioned are the property of their respective owners. The use of the word partner
does not imply a partnership relationship between Cisco and any other company. (1110R)
Any Internet Protocol (IP) addresses and phone numbers used in this document are not intended to be
actual addresses and phone numbers. Any examples, command display output, network topology diagrams,
and other figures included in the document are shown for illustrative purposes only. Any use of actual IP
addresses or phone numbers in illustrative content is unintentional and coincidental.
QoS: Latency and Jitter Configuration Guide, Cisco IOS Release 12.4T
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Reducing Latency and Jitter for Real-Time
Traffic Using Multilink PPP
This module contains information about reducing latency and jitter for real-time traffic on your network.
One Cisco mechanism for reducing latency and jitter for real-time traffic is Multilink PPP (MLP), also
known as Multilink. This module contains conceptual information about Multilink and describes how
Multilink PPP can be used with network peers to reduce latency and jitter for real-time traffic on your
network.
•
•
•
•
Finding Feature Information, page 3
Information About Multilink, page 3
Where to Go Next, page 7
Additional References, page 7
Finding Feature Information
Your software release may not support all the features documented in this module. For the latest feature
information and caveats, see the release notes for your platform and software release. To find information
about the features documented in this module, and to see a list of the releases in which each feature is
supported, see the Feature Information Table at the end of this document.
Use Cisco Feature Navigator to find information about platform support and Cisco software image support.
To access Cisco Feature Navigator, go to www.cisco.com/go/cfn. An account on Cisco.com is not required.
Information About Multilink
•
•
•
•
Restrictions for Multilink, page 3
Multilink Functionality, page 4
Multiclass Multilink PPP, page 6
Distributed Multilink PPP, page 6
Restrictions for Multilink
Multilink uses first-in first-out (FIFO) queuing to queue and interleave packets. Alternative mechanisms
such as low latency queuing (LLQ), weighted fair queuing (WFQ), or class-based weighted fair queuing
(CBWFQ) may be used. If you want to use one of these alternative mechanisms, enable it before
configuring Multilink. For more information about queuing mechanisms, see the "Configuring Weighted
Fair Queueing" module.
QoS: Latency and Jitter Configuration Guide, Cisco IOS Release 12.4T
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Multilink Functionality
Multilink Interleaving
Multilink Functionality
At the top level, Multilink provides packet interleaving, packet fragmentation, and packet resequencing
across multiple logical data links. The packet interleaving, packet fragmentation, and packet resequencing
is used to accommodate the fast transmission times required for sending real-time packets (for example,
voice packets) across the network links. Multilink is especially useful over slow network links (that is, a
network link with a link speed less than or equal to 768 kbps).
•
•
•
•
Multilink Interleaving, page 4
Multilink Fragmentation, page 4
Multilink Resequencing, page 5
Multilink Bundles and Their Network Links, page 6
Multilink Interleaving
Multilink interleaving is based upon two other integral Multilink activities:
•
•
The ability to fragment packets (or datagrams)
The ability to multiplex at least two independent data streams
The term interleaving comes from the latter activity, that is, the interleaving of two (or more) independent
data streams which are processed independently by the network peer.
Multilink interleaving is a mechanism that allows short, real-time (that is, time-sensitive) packets to be
transmitted to a network peer within a certain amount of time (the "delay budget"). To accomplish this task,
Multilink interleaving interrupts the transmission of large non-time-sensitive (sometimes referred to as
"bulk") datagrams or packets in favor of transmitting the time-sensitive packet. Once the real-time packet is
sent, the system resumes sending the bulk packet.
An example may help to illustrate the concept of delay budget. The network starts transmitting a large
datagram to a network peer. This large datagram takes 500 milliseconds (ms) to transmit. Three
milliseconds later (while the large datagram is still being transmitted), a voice packet arrives in the transmit
queue. By the time the large datagram is completely transmitted (497 ms later) the voice packet (which is
highly time-sensitive) is subject to unacceptable delay (that is, its delay budget is exceeded).
Multilink interleaving is particularly useful for applications where too much latency (that is, delay) is
detrimental to the function of the application, such as Voice over IP (VoIP). However, it is also beneficial
for other forms of "interactive" data, such as Telnet packets where the Telnet packets echo the keystrokes
entered by the user at a keyboard.
Multilink Fragmentation
With Multilink fragmentation, the large datagram is fragmented ("chopped") into a number of small packet
fragments, Multilink headers are added to the packet fragments, and the packet fragments are transmitted
individually to a network peer.
When interleaving is enabled, the packet fragments are small enough so that the time it takes to transmit
them does not exceed the time budgeted for transmitting the real-time (time-sensitive) data packet. The
real-time data packets are interleaved between the fragments of the large datagram.
Each time Multilink prepares to send another data packet fragment or frame to the receiving network peer,
Multilink first checks to see if a real-time (time-sensitive) packet has arrived in the transmit queue. If so,
the high-priority packet is sent first before sending the next fragment from the large datagram.
The time delay before the priority packets arrive at the receiving network link is subject to the usual
serialization delays at the network link level. That is, any other data already being transmitted has to be
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Reducing Latency and Jitter for Real-Time Traffic Using Multilink PPP
Multilink Resequencing
finished before the priority packet can be sent. By segmenting long datagrams into small fragments, and
checking for newly arrived priority frames between fragments, the priority frame is delayed only by the
time it takes to transmit a previously queued fragment rather than a complete large datagram.
Thus, the maximum size of the fragments dictates the responsiveness for insertion of priority packets into
the stream. The fragment size can be tuned by adjusting the fragment delay with the ppp multilink
fragment delay command.
To ensure correct order of transmission and reassembly (which occurs later), multilink headers are added to
the large datagram fragments after the packets are dequeued and ready to be sent.
The figure below is a simplified illustration of how Multilink fragments and interleaves packets.
Figure 1
Multilink Fragmentation and Interleaving
In the figure above, both IP voice packets and a large datagram arrive at the interface from a single network
link. Your network may have multiple links. The IP voice packet and large datagram are queued according
to their classification. The large datagram is fragmented (the IP voice packets are not). The IP voice packets
are interleaved between the fragments of the large datagram, to which multilink headers are added.
Packets Dequeued and Transmitted
When the large datagram is dequeued, and space becomes available on a member link, Multilink takes a
fragment from the original large datagram and transmits the fragments over that link. If an IP voice packet
(or other real-time packet) arrives at the transmit queue before Multilink has completely sent the datagram
fragment, the next time a link is available to send more packets, Multilink will dequeue and send the highpriority packet. The high-priority packet will be sent instead of another fragment from the large datagram.
Multilink Resequencing
A multilink bundle is a virtual Point-to-Point Protocol (PPP) connection or session over a network link. A
multilink bundle at the transmitting end of the network sends the fragments to a multilink bundle on the
receiving end of the network link.
The multilink bundle at the receiving end of the network accepts the fragments from the transmitting
multilink bundle.
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Multiclass Multilink PPP
Multilink Bundles and Their Network Links
As fragments are received, the multilink bundle reassembles (resequences) the original large datagram from
the fragments using the sequence number in the multilink header attached to the fragment by the sender.
The reassembled large datagrams are then forwarded in normal fashion.
Multilink Bundles and Their Network Links
As mentioned earlier, a multilink bundle is a virtual PPP connection over a network link. The transmitting
multilink bundle transmits the packet over a network link to a receiving multilink bundle, where the
multilink bundle reassembles the fragments using the sequence number in the multilink header of the
fragment.
The individual member links in a multilink bundle are standard serial PPP connections. Most forms of PPP
connections may be used as member links in a bundle, including PPP over ATM, PPP over Frame Relay,
and PPP over dial interfaces. However, there may be certain limitations and issues associated with using
PPP sessions over certain media types, particularly those for "tunneling" protocols such as PPP over ATM,
PPP over Frame Relay, and PPP over Ethernet.
Multiclass Multilink PPP
Multiclass Multilink PPP (MCMP) is based on RFC 2686: Multi-Class Extension to Multi-Link PPP .
Multiclass Multilink PPP is an extension to the multilink functionality that adds the ability to divide
network traffic over the multilink bundle into several independently sequenced streams of fragments.
Multilink, as defined by RFC 1990: The PPP Multilink Protocol (MP) , provides for one sequenced stream
only. RFC 1990 also implicitly allows one additional unsequenced stream, as large datagrams may be
transmitted without multilink headers as long as the large datagrams do not need to be fragmented.
In Multiclass Multilink PPP, outgoing packets may be divided into as many as 16 different streams, for
which RFC 2686 uses the term classes. Each stream or class has its own governing sequence number, and
the receiving network peer (bundle) sorts and processes each stream independently.
Packets can still be sent without multilink headers. However, part of the purpose behind Multiclass
Multilink PPP is to reduce or eliminate the need to send unsequenced data.
Multiclass Multilink PPP was created explicitly to allow the packets to be divided into several preemptable
classes, so that any lower priority class could be interrupted in favor of sending a packet from a higher
priority class. Each class of data can be fragmented, and all classes are expected to be fragmented (with the
possible exception of the highest priority class). Also, frames from the different streams may be mixed if
necessary.
Multiclass Multilink PPP was created as a mechanism to allow implementations to do interleaving, yet
without giving up the sequencing of the interleaved packets such as occurs with standard interleaving.
In the Cisco IOS software, when Multilink Multiclass PPP is used instead of standard interleaving, the
regular non-priority data is fragmented and transmitted in one class, and interleaved frames are sent in a
separate class. Specifically, the regular traffic is sent in class 0 and the interleaved frames are sent in class
1. Thus, interleaving works just as it does with standard interleaving, except that the interleaved frames are
sent in class 1 rather than as unsequenced frames. Multilink does not transmit data using additional classes,
although Multilink is capable of receiving data from peers that do.
Multiclass Multilink PPP must be successfully negotiated with the peer system. If interleaving and
Multiclass Multilink PPP are both configured, but the use of Multiclass Multilink PPP cannot be negotiated
with the peer system, standard interleaving will be used.
Distributed Multilink PPP
Distributed Multilink PPP (dMLP) is an implementation of Multilink on systems that support distributed
processing. With distributed processing, packet processing can be handled by "dedicated hardware"--that is,
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Reducing Latency and Jitter for Real-Time Traffic Using Multilink PPP
Where to Go Next
either by the CPU or by another internal device such as a Versatile Interface Processor (VIP) inside the
router or a FlexWAN inside the switch. This dedicated hardware can also be referred to as the "dMLP
engine."
One system that supports distributed processing is the Cisco 7500 series router with a Versatile Interface
Processor (VIP2-40 or higher). Distributed processing is supported on a number of additional routers and
switches as well. Refer to the documentation for your specific router or switch to see if it supports
distributed processing.
Note
On a Cisco 7500 series router, a VIP2-50 or higher is recommended when the aggregate line rate of the port
adapters on the VIP is greater than DS3. A VIP2-50 card is required for OC-3 rates.
With dMLP, packet fragmentation, interleaving, and fragment reassembly are done by the dMLP engine
instead of by the Cisco IOS software. However, the Cisco IOS software manages the member links, creates
and disassembles the bundles, and handles the control plane processing (including the handling of all PPP
control packets).
However, once a bundle is established, the handling of Multilink packets is turned over to the dMLP
engine. The dMLP engine handles all the multilink data-path functionality, including fragmentation,
interleaving, multilink encapsulation, load balancing among the multiple links, and sorting and reassembly
of inbound fragments.
The capabilities of the dMLP engines vary widely, and they may not always behave like the Cisco IOS
Multilink feature. The dMLP engine may fragment and load balance using entirely different schemes than
those used by the Cisco IOS software, and they may not support the same multilink features. For more
information, refer to the documentation for the dMLP engine you are using.
Where to Go Next
The next step is to go to the module containing the instructions for the type of Multilink PPP you want to
use, as listed below.
To use Multilink PPP over Frame Relay, see the "Using Multilink PPP over Frame Relay" module.
To use Multilink PPP over ATM links, see the "Using Multilink PPP over ATM Links" module.
To use Multilink PPP over dialer interface links, see the "Using Multilink PPP over Dialer Interface Links"
module.
To use Multilink PPP over serial interface links, see the "Using Multilink PPP over Serial Interface Links"
module.
Note
If you are using an ASR 1000 Series Router, follow the instructions for using Multilink PPP over serial
interface links.
Additional References
The following sections provide additional references about Multilink.
QoS: Latency and Jitter Configuration Guide, Cisco IOS Release 12.4T
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Reducing Latency and Jitter for Real-Time Traffic Using Multilink PPP
Additional References
Related Documents
Related Topic
Document Title
QoS commands: complete command syntax,
Cisco IOS Quality of Service Solutions Command
command modes, command history, defaults, usage Reference
guidelines, and examples
LLQ, WFQ, CBWFQ, PQ, CQ, FIFO and other
queueing mechanisms
"Configuring Weighted Fair Queueing" module
Frame Relay configurations
Configuring Frame Relay" module
ATM configurations
"Configuring ATM" module
Multiclass Multilink PPP
"Multiclass Multilink PPP" module
Multilink PPP configuration information
"Configuring Media-Independent PPP and
Multilink PPP" module
Multilink PPP over ATM links (including ATM
interfaces and ATM PVCs)
"Using Multilink PPP over ATM Links" module
Multilink PPP over Frame Relay
"Using Multilink PPP over Frame Relay" module
Multilink PPP over dialer interface links
"Using Multilink PPP over Dialer Interface Links"
module
Multilink PPP over serial interface links
"Using Multilink PPP over Serial Interface Links"
module
Standards
Standard
Title
No new or modified standards are supported, and
support for existing standards has not been
modified.
--
MIBs
MIB
MIBs Link
No new or modified MIBs are supported, and
support for existing MIBs has not been modified.
To locate and download MIBs for selected
platforms, Cisco IOS releases, and feature sets, use
Cisco MIB Locator found at the following URL:
http://www.cisco.com/go/mibs
RFCs
RFC
Title
RFC 1990
The PPP Multilink Protocol (MP)
QoS: Latency and Jitter Configuration Guide, Cisco IOS Release 12.4T
8
Reducing Latency and Jitter for Real-Time Traffic Using Multilink PPP
RFC
Title
RFC 2686
Multi-Class Extension to Multi-Link PPP
Technical Assistance
Description
Link
The Cisco Support and Documentation website
provides online resources to download
documentation, software, and tools. Use these
resources to install and configure the software and
to troubleshoot and resolve technical issues with
Cisco products and technologies. Access to most
tools on the Cisco Support and Documentation
website requires a Cisco.com user ID and
password.
http://www.cisco.com/cisco/web/support/
index.html
Cisco and the Cisco logo are trademarks or registered trademarks of Cisco and/or its affiliates in the U.S.
and other countries. To view a list of Cisco trademarks, go to this URL: www.cisco.com/go/trademarks.
Third-party trademarks mentioned are the property of their respective owners. The use of the word partner
does not imply a partnership relationship between Cisco and any other company. (1110R)
Any Internet Protocol (IP) addresses and phone numbers used in this document are not intended to be
actual addresses and phone numbers. Any examples, command display output, network topology diagrams,
and other figures included in the document are shown for illustrative purposes only. Any use of actual IP
addresses or phone numbers in illustrative content is unintentional and coincidental.
QoS: Latency and Jitter Configuration Guide, Cisco IOS Release 12.4T
9
Distributed Multilink PPP
QoS: Latency and Jitter Configuration Guide, Cisco IOS Release 12.4T
10
Using Multilink PPP over ATM Links
This module contains conceptual information and configuration tasks for using Multilink PPP over ATM
links. Multilink PPP is a method that is used to reduce latency and jitter for real-time traffic.
•
•
•
•
•
•
•
•
•
Finding Feature Information, page 11
Prerequisites for Using Multilink PPP over ATM Links, page 11
Restrictions for Using Multilink PPP over ATM Links, page 11
Information About Using Multilink PPP over ATM Links, page 12
How to Configure Multilink PPP over ATM Links, page 12
Configuration Examples for Using Multilink PPP over ATM Links, page 21
Where to Go Next, page 24
Additional References, page 24
Feature Information for Using Multilink PPP over ATM Links, page 26
Finding Feature Information
Your software release may not support all the features documented in this module. For the latest feature
information and caveats, see the release notes for your platform and software release. To find information
about the features documented in this module, and to see a list of the releases in which each feature is
supported, see the Feature Information Table at the end of this document.
Use Cisco Feature Navigator to find information about platform support and Cisco software image support.
To access Cisco Feature Navigator, go to www.cisco.com/go/cfn. An account on Cisco.com is not required.
Prerequisites for Using Multilink PPP over ATM Links
•
•
Be familiar with the concepts in the "Reducing Latency and Jitter for Real-Time Traffic Using
Multilink PPP" module.
Multilink PPP uses first-in first-out (FIFO) queueing for queueing and interleaving packets. Other
queueing mechanisms such as low latency queueing (LLQ), weighted fair queueing (WFQ), and classbased weighted fair queueing (CBWFQ) can be used. If you want to use one of these alternative
mechanisms, enable it before configuring Multilink.
Restrictions for Using Multilink PPP over ATM Links
•
Only Voice over IP (VoIP) is supported; Voice over ATM is not supported.
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MQC and Multilink PPP over ATM Links
Information About Using Multilink PPP over ATM Links
•
Multilink PPP over ATM must use the following ATM network modules:
◦
◦
◦
Multiport T1/E1 ATM Network Module with Inverse Multiplexing over ATM
ATM OC-3 Network Module
Enhanced ATM Port Adapter
Information About Using Multilink PPP over ATM Links
•
•
•
MQC and Multilink PPP over ATM Links, page 12
VirtualTemplateInterfaces, page 12
Multilink Group Interfaces, page 12
MQC and Multilink PPP over ATM Links
Before using Multilink PPP over ATM links, a policy map must be created. (See the MQC and Multilink
PPP over ATM Links, page 12.) Policy maps are created using the Modular Quality of Service (QoS)
Command-Line Interface (CLI) (MQC).
VirtualTemplateInterfaces
A virtual template interface is a logical interface that is configured with generic configuration information
for a specific purpose or a configuration common to specific users, plus router-dependent information. The
template takes the form of a list of Cisco IOS interface commands that are applied to virtual access
interfaces, as needed.
Multilink Group Interfaces
A multilink group interface is a collection of interfaces that are bundled together in the multilink PPP
configuration. With a multilink group interface, you can bundle interfaces into logical multilink groups.
How to Configure Multilink PPP over ATM Links
While the first two procedures are listed as optional, you must choose one or the other according to the
Cisco router that you are using in your network.
•
•
•
•
Configuring Multilink PPP over ATM Links on a Virtual Template Interface, page 12
Configuring Multilink PPP over ATM Links on a Multilink Group Interface, page 15
Associating the Virtual Template Interface with an ATM PVC, page 18
Verifying the Multilink PPP over ATM Links Configuration, page 20
Configuring Multilink PPP over ATM Links on a Virtual Template Interface
These steps apply if you are using the Cisco 7500 series router or the Cisco 7600 series router only. If you
are using another series of Cisco router, do not complete these steps. Instead, advance to the Configuring
Multilink PPP over ATM Links on a Multilink Group Interface, page 15.
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Using Multilink PPP over ATM Links
How to Configure Multilink PPP over ATM Links
Before proceeding with this task, you must create a policy map. The policy map contains the configuration
parameters used to apply a specific QoS feature, such as distributed LLQ (dLLQ), to the network traffic.
SUMMARY STEPS
1. enable
2. configure terminal
3. interface virtual-template number
4. bandwidth kbps
5. ip address ip-address mask [secondary]
6. service-policy output policy-map-name
7. service-policy input policy-map-name
8. ppp multilink
9. ppp multilink fragment delay milliseconds [microseconds]
10. ppp multilink interleave
11. end
DETAILED STEPS
Command or Action
Step 1 enable
Purpose
Enables privileged EXEC mode.
•
Enter your password if prompted.
Example:
Router> enable
Step 2 configure terminal
Enters global configuration mode.
Example:
Router# configure terminal
Step 3 interface virtual-template number
Creates a virtual template and enters interface configuration mode.
•
Enter the virtual template number.
Example:
Router(config)# interface virtualtemplate 4
Step 4 bandwidth kbps
Sets the bandwidth value for an interface.
•
Enter the bandwidth value in kilobits per second.
Example:
Router(config-if)# bandwidth 32
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Using Multilink PPP over ATM Links
How to Configure Multilink PPP over ATM Links
Command or Action
Step 5 ip address ip-address mask [secondary]
Example:
Purpose
Sets a primary IP address for an interface. This command can also
set the optional secondary IP address for an interface.
•
Enter the primary IP address (and, optionally, the secondary IP
address).
Router(config-if)# ip address 10.10.100.1
255.255.255.0
Step 6 service-policy output policy-map-name
Example:
Attaches the previously created QoS traffic policy (policy map). The
policy map evaluates and applies QoS features for traffic leaving the
interface.
•
Enter the policy map name.
Router(config-if)# service-policy output
policy1
Step 7 service-policy input policy-map-name
Example:
Attaches the previously created QoS traffic policy (policy map). The
policy map evaluates and applies QoS features for traffic enteringthe
interface.
•
Enter the policy map name.
Router(config-if)# service-policy input
policy1
Step 8 ppp multilink
Enables Multilink PPP (MLP) on the interface.
Example:
Router(config-if)# ppp multilink
Step 9 ppp multilink fragment delay milliseconds
[microseconds]
Specifies a maximum size in units of time for packet fragments on an
MLP bundle.
•
Example:
Router(config-if)# ppp multilink fragment
delay 20
Step 10 ppp multilink interleave
Enter the maximum amount of time, in milliseconds.
Note The fragment delay can be calculated using the following
formula:
fragment delay = (fragment size * 8)/bandwidth
Enables interleaving of packets among the fragments of larger
packets on a multilink bundle.
Example:
Router(config-if)# ppp multilink
interleave
Step 11 end
(Optional) Exits interface configuration mode and returns to
privileged EXEC mode.
Example:
Router(config-if)# end
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Configuring Multilink PPP over ATM Links on a Multilink Group Interface
How to Configure Multilink PPP over ATM Links
Configuring Multilink PPP over ATM Links on a Multilink Group Interface
If you are using the Cisco 7500 series router or the Cisco 7600 series router, do not complete these steps.
Instead, complete the steps in Configuring Multilink PPP over ATM Links on a Virtual Template
Interface, page 12.
Before proceeding with this task, you must create a policy map. The policy map contains the configuration
parameters used to apply a specific QoS feature, such as distributed LLQ (dLLQ), to the network traffic.
SUMMARY STEPS
1. enable
2. configure terminal
3. interface multilink multilink-bundle-number
4. ip address ip-address mask [secondary]
5. service-policy output policy-map-name
6. service-policy input policy-map-name
7. ppp multilink fragment delay milliseconds [microseconds]
8. ppp multilink interleave
9. ppp multilink multiclass
10. end
DETAILED STEPS
Command or Action
Step 1 enable
Purpose
Enables privileged EXEC mode.
•
Enter your password if prompted.
Example:
Router> enable
Step 2 configure terminal
Enters global configuration mode.
Example:
Router# configure terminal
Step 3 interface multilink multilink-bundle-number
Creates a multilink bundle and enters interface configuration mode.
•
Enter the multilink bundle number.
Example:
Router(config)# interface multilink 1
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Using Multilink PPP over ATM Links
How to Configure Multilink PPP over ATM Links
Command or Action
Step 4 ip address ip-address mask [secondary]
Example:
Purpose
Sets a primary IP address for an interface. This command can also set
the optional secondary IP address for an interface.
•
Enter the primary IP address (and, optionally, the secondary IP
address).
Router(config-if)# ip address
10.10.100.1 255.255.255.0
Step 5 service-policy output policy-map-name
Example:
Router(config-if)# service-policy
output policy1
Step 6 service-policy input policy-map-name
Example:
Router(config-if)# service-policy input
policy1
Step 7 ppp multilink fragment delay milliseconds
[microseconds]
Attaches the previously created QoS traffic policy (policy map). See
the Configuring Multilink PPP over ATM Links on a Multilink Group
Interface, page 15. The policy map evaluates and applies QoS features
for traffic leaving the interface.
•
Enter the policy map name.
Attaches the previously created QoS traffic policy (policy map). See
the Configuring Multilink PPP over ATM Links on a Multilink Group
Interface, page 15. The policy map evaluates and applies QoS features
for traffic enteringthe interface.
•
Enter the policy map name.
Specifies a maximum size in units of time for packet fragments on a
Multilink PPP (MLP) bundle.
•
Enter the maximum amount of time, in milliseconds.
Example:
Router(config-if)# ppp multilink
fragment delay 20
Step 8 ppp multilink interleave
Enables interleaving of packets among the fragments of larger packets
on a multilink bundle.
Example:
Router(config-if)# ppp multilink
interleave
Step 9 ppp multilink multiclass
(Optional) Enables Multiclass Multilink PPP (MCMP) on an interface.
Note Use this command only if there are multiple links in the
Example:
multilink bundle.
Router(config-if)# ppp multilink
multiclass
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Using Multilink PPP over ATM Links
What to Do Next
Command or Action
Step 10 end
Purpose
(Optional) Exits interface configuration mode and returns to privileged
EXEC mode.
Example:
Router(config-if)# end
•
•
What to Do Next, page 17
Associating the Virtual Template Interface with the Multilink Group, page 17
What to Do Next
After configuring Multilink PPP over ATM links on a multilink group interface, the next step is to
associate the virtual template interface with the multilink group by completing the steps in the following
section.
If you are using a Cisco 7500 series router or a Cisco 7600 series router, advance to the Associating the
Virtual Template Interface with an ATM PVC, page 18 to continue.
Associating the Virtual Template Interface with the Multilink Group
SUMMARY STEPS
1. enable
2. configure terminal
3. interface virtual-template number
4. no ip address [ip-address mask [secondary]]
5. ppp multilink group group-number
6. end
DETAILED STEPS
Command or Action
Step 1 enable
Purpose
Enables privileged EXEC mode.
•
Enter your password if prompted.
Example:
Router> enable
Step 2 configure terminal
Enters global configuration mode.
Example:
Router# configure terminal
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Associating the Virtual Template Interface with an ATM PVC
Associating the Virtual Template Interface with the Multilink Group
Command or Action
Step 3 interface virtual-template number
Example:
Purpose
Creates a virtual template interface that can be configured and
applied dynamically in creating virtual access interfaces, and enters
interface configuration mode.
•
Enter the number used to identify the virtual template interface.
Router(config)# interface virtual-template 2
Step 4 no ip address [ip-address mask [secondary]]
Removes an IP address or disables IP processing.
Example:
Router(config-if)# no ip address
Step 5 ppp multilink group group-number
Restricts a physical link to joining only a designated multilink
group interface.
•
Example:
Enter the multilink group number.
Router(config-if)# ppp multilink group 1
Step 6 end
(Optional) Exits interface configuration mode and returns to
privileged EXEC mode.
Example:
Router(config-if)# end
Associating the Virtual Template Interface with an ATM PVC
SUMMARY STEPS
1. enable
2. configure terminal
3. interface type number [name-tag]
4. pvc [name] vpi / vci [ces | ilmi | qsaal | smds | l2transport]
5. abr output-pcr output-mcr
6. vbr-nrt output-pcr output-scr output-mbs [input-pcr] [input-scr] [input-mbs]
7. protocol ppp virtual-template number
8. end
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Using Multilink PPP over ATM Links
Associating the Virtual Template Interface with the Multilink Group
DETAILED STEPS
Command or Action
Step 1 enable
Purpose
Enables privileged EXEC mode.
•
Enter your password if prompted.
Example:
Router> enable
Step 2 configure terminal
Enters global configuration mode.
Example:
Router# configure terminal
Step 3 interface type number [name-tag]
Configures an interface type and enters interface configuration mode.
•
Enter the interface type and number.
Example:
Router(config)# interface atm2/0/0
Step 4 pvc [name] vpi / vci [ces | ilmi | qsaal | smds |
l2transport]
Creates or assigns a name to an ATM permanent virtual circuit (PVC)
and enters ATM virtual circuit configuration mode.
•
Example:
Enter the ATM PVC name, the network virtual path identifier,
and the network virtual channel identifier.
Router(config-if)# pvc cisco 0/16
Step 5 abr output-pcr output-mcr
Example:
(Optional) Selects available bit rate (ABR) QoS and configures the
output peak cell rate (PCR) and output minimum guaranteed cell rate
(MCR) for an ATM PVC.
•
Enter the output PCR and the output MCR.
Router(config-if-atm-vc)# abr 100 80
Step 6 vbr-nrt output-pcr output-scr output-mbs [inputpcr] [input-scr] [input-mbs]
Example:
Router(config-if-atm-vc)# vbr-nrt 1100
1100 100
Step 7 protocol ppp virtual-template number
Example:
(Optional) Configures the variable bit rate-nonreal time (VBR-NRT)
quality of service (QoS) and specifies the output peak cell rate (PCR),
the output sustainable cell rate (SCR), and the output maximum burst
cell size (MBS) for an ATM PVC, PVC range, switched virtual
circuit (SVC), VC class, or VC bundle member.
•
Enter the output PCR, SCR, and MBS.
Specifies that PPP is established over the ATM PVC using the
configuration from the specified virtual template.
•
Enter the virtual-template number.
Router(config-if-atm-vc)# protocol ppp
virtual-template 2
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Verifying the Multilink PPP over ATM Links Configuration
Associating the Virtual Template Interface with the Multilink Group
Command or Action
Step 8 end
Purpose
(Optional) Exits ATM virtual circuit configuration mode and returns
to privileged EXEC mode.
Example:
Router(config-if-atm-vc)# end
Verifying the Multilink PPP over ATM Links Configuration
SUMMARY STEPS
1. enable
2. show atm pvc [vpi / vci | name | interface atm interface-number[. subinterface-number multipoint]]
[ppp]
3. show interfaces [type number] [first] [last] [accounting]
4. show ppp multilink [active | inactive | interface bundle-interface | [username name] [endpoint
endpoint]]
5. show policy-map interface interface-name [vc [vpi /] vci] [dlci dlci] [input | output]
6. exit
DETAILED STEPS
Command or Action
Step 1 enable
Purpose
Enables privileged EXEC mode.
•
Enter your password if prompted.
Example:
Router> enable
Step 2 show atm pvc [vpi / vci | name | interface atm interfacenumber[. subinterface-number multipoint]] [ppp]
(Optional) Displays all ATM PVCs and traffic
information.
Example:
Router# show atm pvc
Step 3 show interfaces [type number] [first] [last] [accounting]
Example:
Router# show interfaces
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(Optional) Displays statistics for all interfaces that are
configured on the router or access server.
Using Multilink PPP over ATM Links
Configuration Examples for Using Multilink PPP over ATM Links
Command or Action
Purpose
Step 4 show ppp multilink [active | inactive | interface bundleinterface | [username name] [endpoint endpoint]]
(Optional) Displays bundle information for multilink
bundles.
Example:
Router# show ppp multilink
Step 5 show policy-map interface interface-name [vc [vpi /] vci] [dlci (Optional) Displays the packet statistics of all classes
that are configured for all service policies either on the
dlci] [input | output]
specified interface or subinterface or on a specific PVC
on the interface.
Example:
Router# show policy-map interface serial0/0
Step 6 exit
(Optional) Exits privileged EXEC mode.
Example:
Router# exit
Configuration Examples for Using Multilink PPP over ATM
Links
•
•
•
•
•
Example Configuring Multilink PPP over ATM Links on a Virtual Template Interface, page 22
Example Configuring Multilink PPP over ATM Links on a Multilink Group Interface, page 23
Example Associating the Virtual Template Interface with the Multilink Group, page 23
Example Associating the Virtual Template Interface with an ATM PVC, page 24
Example Verifying the Multilink PPP over ATM Links Configuration, page 24
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Example Configuring Multilink PPP over ATM Links on a Virtual Template Interface
Configuration Examples for Using Multilink PPP over ATM Links
Example Configuring Multilink PPP over ATM Links on a Virtual Template
Interface
The following is an example of configuring Multilink PPP over ATM links on a virtual template interface:
Router>
enable
Router#
configure terminal
Router(config)#
interface virtual-template 4
Router(config-if)#
bandwidth 32
Router(config-if)# ip address 10.10.100.1 255.255.255.0
Router(config-if)#
service-policy output policy1
Router(config-if)#
service-policy input policy1
Router(config-if)#
ppp multilink
Router(config-if)#
ppp multilink fragment delay 20
Router(config-if)#
ppp multilink interleave
Router(config-if)#
end
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Example Configuring Multilink PPP over ATM Links on a Multilink Group Interface
Configuration Examples for Using Multilink PPP over ATM Links
Example Configuring Multilink PPP over ATM Links on a Multilink Group
Interface
The following is an example of configuring Multilink PPP over ATM links on a multilink group interface:
Router>
enable
Router#
configure terminal
Router(config)#
interface multilink 1
Router(config-if)# ip address 10.10.100.1 255.255.255.0
Router(config-if)#
service-policy output policy1
Router(config-if)#
service-policy input policy1
Router(config-if)#
ppp multilink fragment delay 20
Router(config-if)#
ppp multilink interleave
Router(config-if)#
ppp multilink multiclass
Router(config-if)#
end
Example Associating the Virtual Template Interface with the Multilink
Group
The following is an example of associating the virtual template interface with the multilink group:
Router>
enable
Router#
configure terminal
Router(config)#
interface virtual-template 2
Router(config-if)#
no ip address
Router(config-if)#
ppp multilink group 1
Router(config-if)#
end
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Example Associating the Virtual Template Interface with an ATM PVC
Where to Go Next
Example Associating the Virtual Template Interface with an ATM PVC
The following is an example of associating the virtual template interface with an ATM PVC:
Router>
enable
Router#
configure terminal
Router(config)#
interface atm2/0/0
Router(config-if)#
pvc cisco 0/16
Router(config-if-atm-vc)#
abr 100 80
Router(config-if-atm-vc)#
protocol ppp virtual-template 2
Router(config-if-atm-vc)#
end
Example Verifying the Multilink PPP over ATM Links Configuration
The following is an example of the show ppp multilink command output. In this example, one multilink
bundle called 7206-2 is on the system. This bundle has two member links: one active link and one inactive
link.
Router# show ppp multilink
Multilink1, bundle name is 7206-2
Endpoint discriminator is 7206-2
Bundle up for 00:00:24, 1/255 load
Receive buffer limit 12000 bytes, frag timeout 1000 ms
0/0 fragments/bytes in reassembly list
0 lost fragments, 0 reordered
0/0 discarded fragments/bytes, 0 lost received
0x0 received sequence, 0x0 sent sequence
Member links: 1 active, 1 inactive (max not set, min not set)
Vi3, since 00:00:24
PPPoATM link, ATM PVC 2/101 on ATM2/0/0
Packets in ATM PVC Holdq: 0 , Particles in ATM PVC Tx Ring: 1
Vt1 (inactive)
Where to Go Next
To use Multilink PPP over Frame Relay, see the "Using Multilink PPP over Frame Relay" module.
To use Multilink PPP over dialer interface links, see the "Using Multilink PPP over Dialer Interface Links"
module.
To use Multilink PPP over serial interface links, see the "Using Multilink PPP over Serial Interface Links"
module.
Additional References
The following sections provide references related to using Multilink PPP over ATM links.
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Using Multilink PPP over ATM Links
Additional References
Related Documents
Related Topic
Document Title
QoS commands: complete command syntax,
Cisco IOS Quality of Service Solutions Command
command modes, command history, defaults, usage Reference
guidelines, and examples
LLQ, WFQ, CBWFQ, PQ, CQ, FIFO, and other
queueing mechanisms
"Configuring Weighted Fair Queueing" module
MQC
"Applying QoS Features Using the MQC" module
Multilink PPP configurations
"Configuring Media-Independent PPP and
Multilink PPP" module
Virtual template interfaces
"Configuring Virtual Template Interfaces" module
Multilink PPP overview module
"Reducing Latency and Jitter for Real-Time Traffic
Using Multilink PPP" module
Multilink PPP over Frame Relay
"Using Multilink PPP over Frame Relay" module
Multilink PPP over dialer interface links
"Using Multilink PPP over Dialer Interface Links"
module
Multilink PPP over serial interface links
"Using Multilink PPP over Serial Interface Links"
module
Standards
Standard
Title
No new or modified standards are supported, and
support for existing standards has not been
modified.
--
MIBs
MIB
MIBs Link
No new or modified MIBs are supported, and
support for existing MIBs has not been modified.
To locate and download MIBs for selected
platforms, Cisco IOS releases, and feature sets, use
Cisco MIB Locator found at the following URL:
http://www.cisco.com/go/mibs
RFCs
RFC
Title
RFC 1990
The PPP Multilink Protocol (MP)
RFC 2686
Multiclass Extension to Multilink PPP (MCML)
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Using Multilink PPP over ATM Links
Feature Information for Using Multilink PPP over ATM Links
Technical Assistance
Description
Link
The Cisco Support and Documentation website
provides online resources to download
documentation, software, and tools. Use these
resources to install and configure the software and
to troubleshoot and resolve technical issues with
Cisco products and technologies. Access to most
tools on the Cisco Support and Documentation
website requires a Cisco.com user ID and
password.
http://www.cisco.com/cisco/web/support/
index.html
Feature Information for Using Multilink PPP over ATM Links
The following table provides release information about the feature or features described in this module.
This table lists only the software release that introduced support for a given feature in a given software
release train. Unless noted otherwise, subsequent releases of that software release train also support that
feature.
Use Cisco Feature Navigator to find information about platform support and Cisco software image support.
To access Cisco Feature Navigator, go to www.cisco.com/go/cfn. An account on Cisco.com is not required.
Table 1
Feature Information for Using Multilink PPP over ATM Links
Feature Name
Releases
Feature Information
Distributed Link Fragmentation
and Interleaving for Frame Relay
and ATM Interfaces on Cisco
7500 Series Routers
12.2(4)T
The Distributed Link
Fragmentation and Interleaving
(dLFI) for Frame Relay and ATM
Interfaces on Cisco 7500 Series
Routers feature extends link
fragmentation and interleaving
functionality to VIP-enabled
Cisco 7500 series routers.
This feature was extensively
rewritten from the perspective of
using Multilink PPP for link
fragmentation and interleaving
over ATM interface links.
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Using Multilink PPP over ATM Links
Feature Name
Releases
Feature Information
Distributed Link Fragmentation
and Interleaving over Leased
Lines
12.2(8)T
The Distributed Link
Fragmentation and Interleaving
over Leased Lines feature extends
distributed link fragmentation and
interleaving functionality to
leased lines.
This feature was extensively
rewritten from the perspective of
using Multilink PPP for link
fragmentation and interleaving
over ATM interface links.
MLP LFI over ATM
Configuration Scaling
12.2(25)S 12.2(27)SBA 15.0(1)M The MLP LFI over ATM
Configuration Scaling feature
supports the transport of real-time
(voice) and non-real-time (data)
traffic on lower-speed Frame
Relay and ATM permanent
virtual circuits (PVCs) without
causing excessive delay of realtime traffic.
The following commands were
introduced or modified: ppp
multilink group
Cisco and the Cisco logo are trademarks or registered trademarks of Cisco and/or its affiliates in the U.S.
and other countries. To view a list of Cisco trademarks, go to this URL: www.cisco.com/go/trademarks.
Third-party trademarks mentioned are the property of their respective owners. The use of the word partner
does not imply a partnership relationship between Cisco and any other company. (1110R)
Any Internet Protocol (IP) addresses and phone numbers used in this document are not intended to be
actual addresses and phone numbers. Any examples, command display output, network topology diagrams,
and other figures included in the document are shown for illustrative purposes only. Any use of actual IP
addresses or phone numbers in illustrative content is unintentional and coincidental.
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Example Verifying the Multilink PPP over ATM Links Configuration
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Using Multilink PPP over Dialer Interface Links
This module contains conceptual information and configuration tasks for using Multilink PPP over dialer
interface links. Multilink PPP is a method used to reduce latency and jitter for real-time traffic.
•
•
•
•
•
•
•
•
•
Finding Feature Information, page 29
Prerequisites for Using Multilink PPP over Dialer Interface Links, page 29
Restrictions for Using Multilink PPP over Dialer Interface Links, page 30
Information About Using Multilink PPP over Dialer Interface Links, page 30
How to Configure Multilink PPP over Dialer Interface Links, page 31
Configuration Examples for Using Multilink PPP over Dialer Interface Links, page 36
Where to Go Next, page 38
Additional References, page 38
Feature Information for Using Multilink PPP over Dialer Interface Links, page 40
Finding Feature Information
Your software release may not support all the features documented in this module. For the latest feature
information and caveats, see the release notes for your platform and software release. To find information
about the features documented in this module, and to see a list of the releases in which each feature is
supported, see the Feature Information Table at the end of this document.
Use Cisco Feature Navigator to find information about platform support and Cisco software image support.
To access Cisco Feature Navigator, go to www.cisco.com/go/cfn. An account on Cisco.com is not required.
Prerequisites for Using Multilink PPP over Dialer Interface
Links
•
•
Be familiar with the concepts in the "Reducing Latency and Jitter for Real-Time Traffic Using
Multilink PPP" module.
Multilink uses first-in first out (FIFO) queuing for queuing and interleaving packets. Other queuing
mechanisms such as low latency queuing (LLQ), weighted fair queuing (WFQ), and class-based
weighted fair queuing (CBWFQ) can be used. If you want to use one of these alternative mechanisms,
enable it before configuring Multilink.
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Dialer Profiles
Restrictions for Using Multilink PPP over Dialer Interface Links
Restrictions for Using Multilink PPP over Dialer Interface
Links
•
Route/switch processing (RSP) is not recommended when using Multilink PPP over dialer interface
links.
Information About Using Multilink PPP over Dialer Interface
Links
•
•
Dialer Profiles, page 30
MQC and Multilink PPP over Dialer Interface Links, page 30
Dialer Profiles
The dialer profiles implementation of dial-on-demand routing (DDR) is based on a separation between
logical and physical interface configuration. Dialer profiles also allow the logical and physical
configurations to be bound together dynamically on a per-call basis.
Dialer profiles are advantageous in the following situations:
•
•
•
•
When you want to share an interface (ISDN, asynchronous, or synchronous serial) to place or receive
calls.
When you want to change any configuration on a per-user basis.
When you want to maximize ISDN channel usage using the Dynamic Multiple Encapsulations feature
to configure various encapsulation types and per-user configurations on the same ISDN B channel at
different times according to the type of call.
When you want to bridge to many destinations, and for avoiding split horizon problems.
Most routed protocols are supported; however, International Organization for Standardization
Connectionless Network Service (ISO CLNS) is not supported.
If you decide to configure dialer profiles, you must disable validation of source addresses for the routed
protocols you support.
MQC and Multilink PPP over Dialer Interface Links
Before using Multilink PPP over dialer interface links, a traffic policy (also known as a policy map) must
be created. (See the MQC and Multilink PPP over Dialer Interface Links, page 30.) Policy maps are
created using the Modular Quality of Service (QoS) Command-Line Interface (CLI) (MQC).
The MQC is a CLI structure that allows users to create traffic policies (policy maps) and attach these policy
maps to interfaces. A policy map contains a traffic class and one or more QoS features. A traffic class is
used to classify traffic. The QoS features in the traffic policy determine how to treat the classified traffic.
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Configuring Multilink PPP over Dialer Interface Links
How to Configure Multilink PPP over Dialer Interface Links
How to Configure Multilink PPP over Dialer Interface Links
•
•
•
Configuring Multilink PPP over Dialer Interface Links, page 31
Associating the Dialer Interface with a BRI, page 34
Verifying the Multilink PPP over Dialer Interface Link Configuration, page 36
Configuring Multilink PPP over Dialer Interface Links
Before proceeding with this task, you must create a policy map. The policy map contains the configuration
parameters used to apply the specific quality of service feature to the network traffic. To create a policy
map, use the MQC. See the MQC and Multilink PPP over Dialer Interface Links, page 30.
SUMMARY STEPS
1. enable
2. configure terminal
3. interface dialer dialer-rotary-group-number
4. ip address ip-address mask [secondary]
5. ip unnumbered type number
6. encapsulation encapsulation-type
7. dialer pool number
8. dialer in-band [no-parity | odd-parity]
9. service-policy output policy-map-name
10. service-policy input policy-map-name
11. ppp authentication {protocol1 [protocol2...]} [if-needed] [list-name | default] [callin] [one-time]
[optional]
12. ppp chap hostname hostname
13. ppp chap password secret
14. ppp multilink [bap]
15. ppp multilink fragment delay milliseconds [microseconds]
16. ppp multilink interleave
17. end
DETAILED STEPS
Command or Action
Step 1 enable
Purpose
Enables privileged EXEC mode.
•
Enter your password if prompted.
Example:
Router> enable
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Using Multilink PPP over Dialer Interface Links
How to Configure Multilink PPP over Dialer Interface Links
Command or Action
Step 2 configure terminal
Purpose
Enters global configuration mode.
Example:
Router# configure terminal
Step 3 interface dialer dialer-rotary-group-number
Defines a dialer rotary group and enters interface configuration mode.
•
Enter the dialer rotary group number.
Example:
Router(config)# interface dialer 1
Step 4 ip address ip-address mask [secondary]
Example:
Sets a primary IP address for an interface. This command can also set
the optional secondary IP address for an interface.
•
Enter the primary IP address (and, optionally, the secondary IP
address).
Router(config-if)# ip address
10.10.100.1 255.255.255.0
Step 5 ip unnumbered type number
Example:
(Optional) Enables IP processing on a serial interface without assigning
an explicit IP address to the interface.
•
Router(config-if)# ip unnumbered
ethernet 0
Step 6 encapsulation encapsulation-type
Enter the type and number of another interface on which the router
has an assigned IP address. It cannot be another unnumbered
interface.
Sets the encapsulation method used by the interface.
•
Enter the encapsulation method. For this feature, enter ppp.
Example:
Router(config-if)# encapsulation ppp
Step 7 dialer pool number
Example:
(Optional) Specifies which dialing pool to use to connect to a specific
destination subnetwork.
•
Enter the dialing pool number.
Router(config-if)# dialer pool 3
Step 8 dialer in-band [no-parity | odd-parity]
(Optional) Specifies that dial-on-demand routing (DDR) is to be
supported.
Example:
Router(config-if)# dialer in-band
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Using Multilink PPP over Dialer Interface Links
How to Configure Multilink PPP over Dialer Interface Links
Command or Action
Step 9 service-policy output policy-map-name
Example:
Purpose
Attaches the previously created QoS traffic policy (policy map). The
policy map evaluates and applies QoS features for traffic leaving the
interface.
•
Enter the policy map name.
Router(config-if)# service-policy
output policy1
Step 10 service-policy input policy-map-name
Example:
Router(config-if)# service-policy input
policy1
Step 11 ppp authentication {protocol1 [protocol2...]}
[if-needed] [list-name | default] [callin] [onetime] [optional]
Attaches the previously created QoS traffic policy (policy map). See
the Configuring Multilink PPP over Dialer Interface Links, page 31.
The policy map evaluates and applies QoS features for traffic
enteringthe interface.
•
Enter the policy map name.
Enables at least one Point-to-Point Protocol (PPP) authentication
protocol and specifies the order in which the protocols are selected on
the interface.
•
Enter the PPP authentication protocol to be used.
Example:
Router(config-if)# ppp authentication
chap
Step 12 ppp chap hostname hostname
Example:
Creates a pool of dialup routers that all appear to be the same host
when authenticating with Challenge Handshake Authentication
Protocol (CHAP).
•
Enter the name sent in the CHAP challenge.
Router(config-if)# ppp chap hostname
ISPCorp
Step 13 ppp chap password secret
Example:
Router(config-if)# ppp chap password 7
Step 14 ppp multilink [bap]
Enables a router calling a collection of routers that do not support this
command (such as routers running older Cisco IOS software images) to
configure a CHAP secret password to use in response to challenges
from an unknown peer.
•
Enter the secret password used to compute the response value for
any CHAP challenge from an unknown peer.
Enables multilink on an interface.
Example:
Router(config-if)# ppp multilink
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Associating the Dialer Interface with a BRI
How to Configure Multilink PPP over Dialer Interface Links
Command or Action
Step 15 ppp multilink fragment delay milliseconds
[microseconds]
Purpose
Specifies a maximum size in units of time for packet fragments on a
Multilink PPP (MLP) bundle.
•
Enter the maximum amount of time, in milliseconds.
Example:
Router(config-if)# ppp multilink
fragment delay 20
Step 16 ppp multilink interleave
Enables interleaving of packets among the fragments of larger packets
on a multilink bundle.
Example:
Router(config-if)# ppp multilink
interleave
Step 17 end
(Optional) Exits interface configuration mode.
Example:
Router(config-if)# end
Associating the Dialer Interface with a BRI
SUMMARY STEPS
1. enable
2. configure terminal
3. interface bri number
4. dialer pool-member number [priority priority] [min-link minimum] [max-link maximum]
5. dialer rotary-group interface-number
6. ppp multilink [bap]
7. end
DETAILED STEPS
Command or Action
Step 1 enable
Purpose
Enables privileged EXEC mode.
•
Example:
Router> enable
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Enter your password if prompted.
Using Multilink PPP over Dialer Interface Links
How to Configure Multilink PPP over Dialer Interface Links
Command or Action
Purpose
Step 2 configure terminal
Enters global configuration mode.
Example:
Router# configure terminal
Step 3 interface bri number
Configures a BRI interface and enters interface configuration
mode.
•
Example:
Enter port, connector, or interface card number.
Router(config)# interface bri 1
Step 4 dialer pool-member number [priority priority] [minlink minimum] [max-link maximum]
(Optional) Configures a physical interface to be a member of a
dialer profile dialing pool.
•
Enter the dialer profile dialing pool number.
Example:
Router(config-if)# dialer pool-member 3
Step 5 dialer rotary-group interface-number
(Optional) Includes a specified interface in a dialer rotary group.
•
Example:
Enter the number of the dialer interface (defined in
Associating the Dialer Interface with a BRI, page 34) in
whose rotary group this interface is to be included.
Router(config-if)# dialer rotary-group 1
Step 6 ppp multilink [bap]
Enables Multilink on an interface.
Example:
Router(config-if)# ppp multilink
Step 7 end
(Optional) Exits interface configuration mode.
Example:
Router(config-if)# end
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Verifying the Multilink PPP over Dialer Interface Link Configuration
Configuration Examples for Using Multilink PPP over Dialer Interface Links
Verifying the Multilink PPP over Dialer Interface Link Configuration
SUMMARY STEPS
1. enable
2. show interfaces [type number] [first] [last] [accounting]
3. show ppp multilink [active | inactive | interface bundle-interface | [username name] [endpoint
endpoint]]
4. exit
DETAILED STEPS
Command or Action
Purpose
Step 1 enable
Enables privileged EXEC mode.
•
Enter your password if prompted.
Example:
Router> enable
Step 2 show interfaces [type number] [first] [last] [accounting]
(Optional) Displays statistics for all interfaces
configured on the router or access server.
Example:
Router# show interfaces
Step 3 show ppp multilink [active | inactive | interface bundleinterface | [username name] [endpoint endpoint]]
(Optional) Displays bundle information for the
multilink bundles.
Example:
Router# show ppp multilink
Step 4 exit
(Optional) Exits privileged EXEC mode.
Example:
Router# exit
Configuration Examples for Using Multilink PPP over Dialer
Interface Links
•
•
•
Example Configuring Multilink PPP over Dialer Interface Links, page 37
Example Associating the Dialer Interface with a BRI, page 37
Example Verifying the Multilink PPP over Dialer Interface Link Configuration, page 38
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Example Configuring Multilink PPP over Dialer Interface Links
Configuration Examples for Using Multilink PPP over Dialer Interface Links
Example Configuring Multilink PPP over Dialer Interface Links
The following is an example of configuring Multilink PPP over a dialer interface link:
Router>
enable
Router#
configure terminal
Router(config)#
interface dialer 1
Router(config-if)# ip address 10.10.100.1 255.255.255.0
Router(config-if)#
encapsulation ppp
Router(config-if)#
dialer pool 3
Router(config-if)#
service-policy output policy1
Router(config-if)#
service-policy input policy1
Router(config-if)#
ppp authentication chap
Router(config-if)#
ppp chap hostname ISPCorp
Router(config-if)#
ppp chap password 7
Router(config-if)#
ppp multilink
Router(config-if)#
ppp multilink fragment delay 20
Router(config-if)#
ppp multilink interleave
Router(config-if)#
end
Example Associating the Dialer Interface with a BRI
The following is an example of associating the dialer interface with a BRI:
Router>
enable
Router#
configure terminal
Router(config)#
interface bri 1
Router(config-if)#
dialer pool-member 3
Router(config-if)#
ppp multilink
Router(config-if)#
end
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Example Verifying the Multilink PPP over Dialer Interface Link Configuration
Where to Go Next
Example Verifying the Multilink PPP over Dialer Interface Link
Configuration
You can verify the Multilink PPP over dialer interface link configuration by using one or more of the
following show commands:
•
•
show interfaces
show ppp multilink
The following section provides sample output of the show ppp multilink command only. For sample
output of the other commands, see the appropriate Cisco IOS Release 12.3 T command reference
publication.
show ppp multilink Command Output Example
The following is an example of the show ppp multilink command output. In this example, one multilink
bundle called 7206-2 is on the system. This bundle has one member link.
Router# show ppp multilink
Dialer2, bundle name is 7206-2
Username is 7206-2
Endpoint discriminator is 7206-2
Bundle up for 00:00:10, 1/255 load
Receive buffer limit 12000 bytes, frag timeout 1500 ms
0/0 fragments/bytes in reassembly list
0 lost fragments, 0 reordered
0/0 discarded fragments/bytes, 0 lost received
0x0 received sequence, 0x0 sent sequence
Member links:1 (max not set, min not set)
BR2/0:1, since 00:00:09
Where to Go Next
To use Multilink PPP over Frame Relay, see the "Using Multilink PPP over Frame Relay" module.
To use Multilink PPP over ATM links, see the "Using Multilink PPP over ATM Links" module.
To use Multilink PPP over serial interface links, see the "Using Multilink PPP over Serial Interface Links"
module.
Additional References
The following sections provide references related to Multilink PPP over dialer interface links.
Related Documents
Related Topic
Document Title
QoS commands: complete command syntax,
Cisco IOS Quality of Service Solutions Command
command modes, command history, defaults, usage Reference
guidelines, and examples
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Using Multilink PPP over Dialer Interface Links
Additional References
Related Topic
Document Title
LLQ, WFQ, CBWFQ, PQ, CQ, FIFO and other
queueing mechanisms
"Configuring Weighted Fair Queueing" module
MQC
"Applying QoS Features Using the MQC" module
Dialer profiles and DDR
"Preparing to Configure DDR" module
Multilink PPP configuration information
"Configuring Media-Independent PPP and
Multilink PPP" module
Multilink PPP overview module
"Reducing Latency and Jitter for Real-Time Traffic
Using Multilink PPP" module
Multilink PPP over Frame Relay
"Using Multilink PPP over Frame Relay" module
Multilink PPP over ATM links (including ATM
interfaces and ATM PVCs)
"Using Multilink PPP over ATM Links" module
Multilink PPP over serial interface links
"Using Multilink PPP over Serial Interface Links"
module
Standards
Standard
Title
No new or modified standards are supported, and
support for existing standards has not been
modified.
--
MIBs
MIB
MIBs Link
No new or modified MIBs are supported, and
support for existing MIBs has not been modified.
To locate and download MIBs for selected
platforms, Cisco IOS releases, and feature sets, use
Cisco MIB Locator found at the following URL:
http://www.cisco.com/go/mibs
RFCs
RFC
Title
RFC 1990
The PPP Multilink Protocol (MP)
RFC 2686
Multiclass Extension to Multilink PPP (MCML)
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Using Multilink PPP over Dialer Interface Links
Feature Information for Using Multilink PPP over Dialer Interface Links
Technical Assistance
Description
Link
The Cisco Support and Documentation website
provides online resources to download
documentation, software, and tools. Use these
resources to install and configure the software and
to troubleshoot and resolve technical issues with
Cisco products and technologies. Access to most
tools on the Cisco Support and Documentation
website requires a Cisco.com user ID and
password.
http://www.cisco.com/cisco/web/support/
index.html
Feature Information for Using Multilink PPP over Dialer
Interface Links
The following table provides release information about the feature or features described in this module.
This table lists only the software release that introduced support for a given feature in a given software
release train. Unless noted otherwise, subsequent releases of that software release train also support that
feature.
Use Cisco Feature Navigator to find information about platform support and Cisco software image support.
To access Cisco Feature Navigator, go to www.cisco.com/go/cfn. An account on Cisco.com is not required.
Table 2
Feature Information for Using Multilink PPP over Dialer Interface Links
Feature Name
Software Releases
Feature Configuration Information
Distributed Link Fragmentation
and Interleaving Over Leased
Lines
12.2(8)T
The Distributed Link
Fragmentation and Interleaving
over Leased Lines feature extends
distributed link fragmentation and
interleaving functionality to
leased lines.
This feature was extensively
rewritten from the perspective of
using Multilink PPP for link
fragmentation and interleaving
over dialer interface links.
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Using Multilink PPP over Dialer Interface Links
Feature Name
Software Releases
Feature Configuration Information
Distributed Link Fragmentation
and Interleaving for Frame Relay
and ATM Interfaces on Cisco
7500 Series Routers
12.2(4)T
The Distributed Link
Fragmentation and Interleaving
(dLFI) for Frame Relay and ATM
Interfaces on Cisco 7500 Series
Routers feature extends link
fragmentation and interleaving
functionality to VIP-enabled
Cisco 7500 series routers.
This feature was extensively
rewritten from the perspective of
using Multilink PPP for link
fragmentation and interleaving
over dialer interface links.
Cisco and the Cisco logo are trademarks or registered trademarks of Cisco and/or its affiliates in the U.S.
and other countries. To view a list of Cisco trademarks, go to this URL: www.cisco.com/go/trademarks.
Third-party trademarks mentioned are the property of their respective owners. The use of the word partner
does not imply a partnership relationship between Cisco and any other company. (1110R)
Any Internet Protocol (IP) addresses and phone numbers used in this document are not intended to be
actual addresses and phone numbers. Any examples, command display output, network topology diagrams,
and other figures included in the document are shown for illustrative purposes only. Any use of actual IP
addresses or phone numbers in illustrative content is unintentional and coincidental.
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Example Verifying the Multilink PPP over Dialer Interface Link Configuration
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Using Multilink PPP over Frame Relay
Multilink PPP is a method used to reduce latency and jitter for real-time traffic. This module contains
conceptual information and configuration tasks for using Multilink PPP over Frame Relay.
•
•
•
•
•
•
•
•
•
Finding Feature Information, page 43
Prerequisites for Using Multilink PPP over Frame Relay, page 43
Restrictions for Using Multilink PPP over Frame Relay, page 44
Information About Using Multilink PPP over Frame Relay, page 44
How to Configure Multilink PPP over Frame Relay, page 45
Configuration Examples for Multilink PPP over Frame Relay, page 54
Where to Go Next, page 56
Additional References, page 57
Feature Information for Using Multilink PPP over Frame Relay, page 58
Finding Feature Information
Your software release may not support all the features documented in this module. For the latest feature
information and caveats, see the release notes for your platform and software release. To find information
about the features documented in this module, and to see a list of the releases in which each feature is
supported, see the Feature Information Table at the end of this document.
Use Cisco Feature Navigator to find information about platform support and Cisco software image support.
To access Cisco Feature Navigator, go to www.cisco.com/go/cfn. An account on Cisco.com is not required.
Prerequisites for Using Multilink PPP over Frame Relay
Knowledge
•
Be familiar with the concepts in the "Reducing Latency and Jitter for Real-Time Traffic Using
Multilink PPP" module.
Enable Queuing Mechanism
•
Multilink uses first-in first out (FIFO) queuing for queuing and interleaving packets. Other queuing
mechanisms such as low latency queuing (LLQ), weighted fair queuing (WFQ), and class-based
weighted fair queuing (CBWFQ) can be used. If you want to use one of these alternative mechanisms,
enable it before configuring Multilink.
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Frame Relay Traffic Shaping and Multilink PPP over Frame Relay
Restrictions for Using Multilink PPP over Frame Relay
Enable FRTS
•
Frame Relay Traffic Shaping (FRTS) must be enabled on the Frame Relay interface.
Restrictions for Using Multilink PPP over Frame Relay
Number of Links per Multilink Bundle
Only one link per multilink bundle is supported.
VoIP Support
Only Voice over IP (VoIP) is supported; Voice over Frame Relay (VoFR) is not supported.
QoS Configuration
Only one PVC is supported per virtual template.
To handle congestion, a shape policy in an MLP over Frame Relay should be configured via a map class
and attached to the PVC.
Information About Using Multilink PPP over Frame Relay
•
•
•
•
Frame Relay Traffic Shaping and Multilink PPP over Frame Relay, page 44
MQC and Multilink PPP over Frame Relay, page 45
Virtual Template Interfaces, page 45
Multilink Group Interfaces, page 45
Frame Relay Traffic Shaping and Multilink PPP over Frame Relay
Before using Multilink PPP over Frame Relay, FRTS must be enabled.
Note
On the Cisco 7200 and lower series of routers, the frame-relay traffic-shaping command is used to enable
FRTS. On the Cisco 7500 and higher series of routers, the Modular Quality of Service (QoS) CommandLine Interface (CLI) (MQC) is used to enable FRTS. For more information about MQC, see the "MQC and
Multilink PPP over Frame Relay" section.
FRTS is a Cisco traffic shaping mechanism. A traffic shaping mechanism allows you to regulate (that is,
"shape") the packet flow on a network. When you shape traffic, you control the speed of traffic leaving an
interface. This way, you can match the flow of the traffic to the speed of the interface and avoid bottlenecks
on the network.
Cisco has long provided support for forward explicit congestion notification (FECN) for DECnet and OSI,
and backward explicit congestion notification (BECN) for Systems Network Architecture (SNA) traffic
using Logical Link Control, type 2 (LLC2) encapsulation via RFC 1490 and discard eligible (DE) bit
support. FRTS builds upon this existing Frame Relay support with additional capabilities that improve the
scalability and performance of a Frame Relay network, increasing the density of virtual circuits (VCs) and
improving response time.
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MQC and Multilink PPP over Frame Relay
How to Configure Multilink PPP over Frame Relay
FRTS can eliminate bottlenecks in Frame Relay networks that have high-speed connections at the central
site and low-speed connections at branch sites. You can configure rate enforcement--a peak rate configured
to limit outbound traffic--to limit the rate at which data is sent on the VC at the central site.
MQC and Multilink PPP over Frame Relay
Before using Multilink PPP over Frame Relay, a policy map must be created. (See the "Prerequisites"
section.) Policy maps are created using the Modular Quality of Service (QoS) Command-Line Interface
(CLI) (MQC).
Virtual Template Interfaces
A virtual template interface is logical interface configured with generic configuration information for a
specific purpose or configuration common to specific users, plus router-dependent information. The
template takes the form of a list of Cisco IOS interface commands that are applied to virtual access
interfaces, as needed.
Multilink Group Interfaces
A multilink group interface is a collection of interfaces bundled together in the multilink PPP
configuration. With a multilink group interface, you can bundle interfaces into logical multilink groups.
How to Configure Multilink PPP over Frame Relay
While the first two procedures are listed as optional, you must choose one or the other according to the
Cisco router that you are using in your network.
•
•
•
•
Configuring Multilink PPP over Frame Relay on a Virtual Template Interface, page 45
Configuring Multilink PPP over Frame Relay on a Multilink Group Interface, page 48
Associating the Virtual Template Interface with a Frame Relay PVC, page 51
Verifying the Multilink PPP over Frame Relay Configuration, page 53
Configuring Multilink PPP over Frame Relay on a Virtual Template Interface
These steps apply if you are using the Cisco 7500 series router or the Cisco 7600 series router only. If you
are using another series of Cisco router, do not complete these steps. Instead, advance to Configuring
Multilink PPP over Frame Relay on a Multilink Group Interface, page 48.
Before proceeding with this task, you must create a policy map. The policy map contains the configuration
parameters used to apply a specific QoS features such as distributed LLQ (dLLQ) to the network traffic. To
create a policy map and configure the appropriate QoS feature, use the MQC. See the MQC and Multilink
PPP over Frame Relay, page 45.
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Using Multilink PPP over Frame Relay
How to Configure Multilink PPP over Frame Relay
SUMMARY STEPS
1. enable
2. configure terminal
3. interface virtual-template number
4. bandwidth kbps
5. ip address ip-address mask [secondary]
6. service-policy output policy-map-name
7. service-policy input policy-map-name
8. ppp multilink
9. ppp multilink fragment delay milliseconds [microseconds]
10. ppp multilink interleave
11. end
DETAILED STEPS
Command or Action
Step 1 enable
Purpose
Enables privileged EXEC mode.
•
Enter your password if prompted.
Example:
Router> enable
Step 2 configure terminal
Enters global configuration mode.
Example:
Router# configure terminal
Step 3 interface virtual-template number
Creates a virtual template and enters interface configuration mode.
•
Enter the virtual template number.
Example:
Router(config)# interface virtualtemplate 1
Step 4 bandwidth kbps
Sets the bandwidth value for an interface.
•
Example:
Router(config-if)# bandwidth 32
Enter the bandwidth value in kilobits per second.
Note The bandwidth value for the interface should match the traffic
speed of the PVC; for instance, if the VBR peak cell rate is 128
kbps, the kbps option in the bandwidth command should be
entered as 128. Similarly, if the PVC is being shaped to 64 kbps,
the kbps option should be entered as 64.
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Using Multilink PPP over Frame Relay
How to Configure Multilink PPP over Frame Relay
Command or Action
Step 5 ip address ip-address mask [secondary]
Example:
Purpose
Sets a primary IP address for an interface. This command can also set the
optional secondary IP address for an interface.
•
Enter the primary IP address (and, optionally, the secondary IP
address).
Router(config-if)# ip address
10.10.100.1 255.255.255.0
Step 6 service-policy output policy-map-name
Example:
Router(config-if)# service-policy
output policy1
Step 7 service-policy input policy-map-name
Example:
Router(config-if)# service-policy
input policy1
Step 8 ppp multilink
Attaches the previously created QoS traffic policy (policy map). See the
Configuring Multilink PPP over Frame Relay on a Virtual Template
Interface, page 45. The policy map evaluates and applies QoS features
for traffic leaving the interface.
•
Enter the policy map name.
Attaches the previously created QoS traffic policy (policy map). See the
Configuring Multilink PPP over Frame Relay on a Virtual Template
Interface, page 45. The policy map evaluates and applies QoS features
for traffic entering the interface.
•
Enter the policy map name.
Enables MLP on the interface.
Example:
Router(config-if)# ppp multilink
Step 9 ppp multilink fragment delay milliseconds
[microseconds]
Specifies a maximum size in units of time for packet fragments on a
Multilink PPP (MLP) bundle.
•
Example:
Router(config-if)# ppp multilink
fragment delay 20
Step 10 ppp multilink interleave
Enter the maximum amount of time, in milliseconds.
Note The fragment size can be configured using the following formula:
fragment size = bandwidth x fragment-delay / 8
Enables interleaving of packets among the fragments of larger packets on
a multilink bundle.
Example:
Router(config-if)# ppp multilink
interleave
Step 11 end
(Optional) Exits interface configuration mode.
Example:
Router(config-if)# end
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Configuring Multilink PPP over Frame Relay on a Multilink Group Interface
How to Configure Multilink PPP over Frame Relay
Configuring Multilink PPP over Frame Relay on a Multilink Group Interface
If you are using the Cisco 7500 series router or the Cisco 7600 series router, do not complete these steps.
Instead, complete the steps in Configuring Multilink PPP over Frame Relay on a Virtual Template
Interface, page 45.
Before proceeding with this task, you must create a policy map. The policy map contains the configuration
parameters used to apply a specific QoS features such as distributed LLQ (dLLQ) to the network traffic. To
create a policy map and configure the appropriate QoS feature, use the MQC. See the MQC and Multilink
PPP over Frame Relay, page 45.
SUMMARY STEPS
1. enable
2. configure terminal
3. interface multilink multilink-bundle-number
4. ip address ip-address mask [secondary]
5. service-policy output policy-map-name
6. service-policy input policy-map-name
7. ppp multilink fragment delay milliseconds [microseconds]
8. ppp multilink interleave
9. end
DETAILED STEPS
Command or Action
Step 1 enable
Purpose
Enables privileged EXEC mode.
•
Enter your password if prompted.
Example:
Router> enable
Step 2 configure terminal
Enters global configuration mode.
Example:
Router# configure terminal
Step 3 interface multilink multilink-bundle-number
Creates a multilink bundle and enters interface configuration mode.
•
Enter the multilink bundle number.
Example:
Router(config)# interface multilink 1
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Using Multilink PPP over Frame Relay
What to Do Next
Command or Action
Purpose
Step 4 ip address ip-address mask [secondary]
Sets a primary IP address for an interface. This command can also set
the optional secondary IP address for an interface.
•
Example:
Enter the primary IP address (and, optionally, the secondary IP
address).
Router(config-if)# ip address
10.10.100.1 255.255.255.0
Step 5 service-policy output policy-map-name
Example:
Router(config-if)# service-policy
output policy1
Step 6 service-policy input policy-map-name
Example:
Router(config-if)# service-policy input
policy1
Step 7 ppp multilink fragment delay milliseconds
[microseconds]
Attaches the previously created QoS traffic policy (policy map). See the
Configuring Multilink PPP over Frame Relay on a Multilink Group
Interface, page 48. The policy map evaluates and applies QoS features
for traffic leaving the interface.
•
Attaches the previously created QoS traffic policy (policy map). See the
Configuring Multilink PPP over Frame Relay on a Multilink Group
Interface, page 48. The policy map evaluates and applies QoS features
for traffic entering the interface.
•
Enter the policy map name.
Specifies a maximum size in units of time for packet fragments on a
multilink bundle.
•
Example:
Enter the policy map name.
Enter the maximum amount of time, in milliseconds, required to
transmit a fragment.
Router(config-if)# ppp multilink
fragment delay 20
Step 8 ppp multilink interleave
Enables interleaving of packets among the fragments of larger packets
on a multilink bundle.
Example:
Router(config-if)# ppp multilink
interleave
Step 9 end
(Optional) Exits interface configuration mode.
Example:
Router(config-if)# end
•
•
What to Do Next, page 49
Associating the Virtual Template Interface with the Multilink Group, page 50
What to Do Next
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Using Multilink PPP over Frame Relay
Associating the Virtual Template Interface with the Multilink Group
After configuring Multilink PPP over Frame Relay on a multilink group interface, the next step is to
associate the virtual template interface with the multilink group by completing the steps in the following
section.
If you are using a Cisco 7500 series router or a Cisco 7600 series router, advance to Associating the Virtual
Template Interface with a Frame Relay PVC, page 51 to continue.
Associating the Virtual Template Interface with the Multilink Group
SUMMARY STEPS
1. enable
2. configure terminal
3. interface virtual-template number
4. no ip address
5. ppp multilink group group-number
6. end
DETAILED STEPS
Command or Action
Step 1 enable
Purpose
Enables privileged EXEC mode.
•
Enter your password if prompted.
Example:
Router> enable
Step 2 configure terminal
Enters global configuration mode.
Example:
Router# configure terminal
Step 3 interface virtual-template number
Example:
Creates a virtual template interface that can be configured and applied
dynamically in creating virtual access interfaces, and enters interface
configuration mode.
•
Enter the number used to identify the virtual template interface.
Router# interface virtual-template 1
Step 4 no ip address
Removes an IP address or disables IP processing.
Example:
Router(config-if)# no ip address
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Associating the Virtual Template Interface with a Frame Relay PVC
Associating the Virtual Template Interface with the Multilink Group
Command or Action
Purpose
Step 5 ppp multilink group group-number
Restricts a physical link to joining only a designated multilink group
interface.
•
Example:
Enter the multilink group number.
Router(config-if)# ppp multilink group 1
Step 6 end
(Optional) Exits interface configuration mode.
Example:
Router(config-if)# end
Associating the Virtual Template Interface with a Frame Relay PVC
SUMMARY STEPS
1. enable
2. configure terminal
3. interface type number [name-tag]
4. frame-relay traffic-shaping
5. frame-relay interface-dlci dlci [ietf | cisco] [voice-cir cir] [ppp virtual-template-name]
6. class name
7. end
DETAILED STEPS
Command or Action
Step 1 enable
Purpose
Enables privileged EXEC mode.
•
Enter your password if prompted.
Example:
Router> enable
Step 2 configure terminal
Enters global configuration mode.
Example:
Router# configure terminal
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Using Multilink PPP over Frame Relay
Associating the Virtual Template Interface with the Multilink Group
Command or Action
Step 3 interface type number [name-tag]
Purpose
Configures an interface type and enters interface configuration mode.
•
Enter the interface type and number.
Example:
Router(config)# interface
serial1/0/0/1:0
Step 4 frame-relay traffic-shaping
Example:
Enables both traffic shaping and per-virtual-circuit queueing for all
permanent virtual circuits (PVCs) and switched virtual circuits (SVCs) on
a Frame Relay interface.
Note Use this command on Cisco 7200 and lower series routers only . Do
not use this command on Cisco 7500 or higher series routers. For
Cisco 7500 and higher series routers, use the MQC instead of this
command.
Router(config-if)# frame-relay
traffic-shaping
Step 5 frame-relay interface-dlci dlci [ietf | cisco]
[voice-cir cir] [ppp virtual-template-name]
Example:
Assigns a data-link connection identifier (DLCI) to a specified Frame
Relay subinterface on the router or access server, assigns a specific PVC
to a DLCI, or applies a virtual template configuration for a PPP session.
Enters Frame Relay DLCI configuration mode.
•
Router(config-if)# frame-relay
interface-dlci 100 ppp virtualtemplate1
Step 6 class name
Associates a map class with a specified DLCI.
•
Example:
Router(config-fr-dlci)# class frdlci
Step 7 end
Enter the DLCI number and any optional keywords and arguments,
as appropriate.
Enter the name of the map class to associate with the specified DLCI.
Note Use this command on Cisco 7200 and lower series routers only .
For Cisco 7500 and higher series routers, this command is not
needed.
(Optional) Exits Frame Relay DLCI configuration mode.
Example:
Router(config-fr-dlci)# end
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Verifying the Multilink PPP over Frame Relay Configuration
Associating the Virtual Template Interface with the Multilink Group
Verifying the Multilink PPP over Frame Relay Configuration
SUMMARY STEPS
1. enable
2. show frame-relay pvc [interface interface] [dlci] [64-bit]
3. show interfaces [type number] [first] [last] [accounting]
4. show ppp multilink [active | inactive | interface bundle-interface | [username name] [endpoint
endpoint]]
5. show policy-map interface interface-name [vc [vpi/] vci] [dlci dlci] [input | output]
6. exit
DETAILED STEPS
Command or Action
Purpose
Step 1 enable
Enables privileged EXEC mode.
•
Enter your password if prompted.
Example:
Router> enable
Step 2 show frame-relay pvc [interface interface] [dlci] [64-bit]
(Optional) Displays statistics about permanent virtual
circuits (PVCs) for Frame Relay interfaces.
Example:
Router# show frame-relay pvc
Step 3 show interfaces [type number] [first] [last] [accounting]
(Optional) Displays statistics for all interfaces configured
on the router or access server.
Example:
Router# show interfaces
Step 4 show ppp multilink [active | inactive | interface bundleinterface | [username name] [endpoint endpoint]]
(Optional) Displays bundle information for multilink
bundles.
Example:
Router# show ppp multilink
Step 5 show policy-map interface interface-name [vc [vpi/] vci]
[dlci dlci] [input | output]
(Optional) Displays the packet statistics of all classes that
are configured for all service policies either on the
specified interface or subinterface or on a specific PVC
on the interface.
Example:
Router# show policy-map interface serial0/0
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Example Configuring Multilink PPP over Frame Relay on a Virtual Template Interface
Configuration Examples for Multilink PPP over Frame Relay
Command or Action
Purpose
Step 6 exit
(Optional) Exits privileged EXEC mode.
Example:
Router# exit
Configuration Examples for Multilink PPP over Frame Relay
•
•
•
•
•
Example Configuring Multilink PPP over Frame Relay on a Virtual Template Interface, page 54
Example Configuring Multilink PPP over Frame Relay on a Multilink Group Interface, page 55
Example Associating the Virtual Template Interface with the Multilink Group, page 55
Example Associating the Virtual Template Interface with a Frame Relay PVC, page 56
Example Verifying the Multilink PPP over Frame Relay Configuration, page 56
Example Configuring Multilink PPP over Frame Relay on a Virtual Template
Interface
The following is an example of configuring Multilink PPP over Frame Relay on a virtual template
interface:
Router>
enable
Router#
configure terminal
Router(config)#
interface virtual-template 1
Router(config-if)#
bandwidth 32
Router(config-if)#
ip address 10.10.100.1 255.255.255.0
Router(config-if)#
service-policy output policy1
Router(config-if)#
service-policy input policy1
Router(config-if)#
ppp multilink
Router(config-if)#
ppp multilink fragment delay 20
Router(config-if)#
ppp multilink interleave
Router(config-if)#
end
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Example Configuring Multilink PPP over Frame Relay on a Multilink Group Interface
Configuration Examples for Multilink PPP over Frame Relay
Example Configuring Multilink PPP over Frame Relay on a Multilink Group
Interface
The following is an example of configuring Multilink PPP over Frame Relay on a multilink group
interface:
Router>
enable
Router#
configure terminal
Router(config)#
interface multilink 1
Router(config-if)#
ip address 10.10.100.1 255.255.255.0
Router(config-if)#
service-policy output policy1
Router(config-if)#
service-policy input policy1
Router(config-if)#
ppp multilink fragment delay 20
Router(config-if)#
ppp multilink interleave
Router(config-if)#
end
Example Associating the Virtual Template Interface with the Multilink
Group
The following is an example of associating the virtual template interface with the multilink group:
Router>
enable
Router#
configure terminal
Router(config)#
interface virtual-template 1
Router(config-if)#
no ip address
Router(config-if)#
ppp multilink group 1
Router(config-if)#
end
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Example Associating the Virtual Template Interface with a Frame Relay PVC
Where to Go Next
Example Associating the Virtual Template Interface with a Frame Relay PVC
The following is an example of associating the virtual template interface with a Frame Relay PVC:
Router>
enable
Router#
configure terminal
Router(config)#
interface serial1/0/0/1:0
Router(config-if)#
frame-relay interface-dlci 100 ppp virtual-template1
Router(config-fr-dlci)#
class frdlci
Router(config-fr-dlci)#
end
Example Verifying the Multilink PPP over Frame Relay Configuration
You can verify the Multilink with PPP over Frame Relay configuration by using one or more of the
following show commands:
•
•
•
•
show frame relay pvc
show interfaces
show ppp multilink
show policy-map interface
The following section provides sample output of the show ppp multilink command only. For sample
output of the other commands, see the appropriate Cisco IOS Release 12.3T command reference
publication.
show ppp multilink Command Output Example
The following is an example of the show ppp multilink command output. In this example, one Multilink
bundle called 7206-2 is on the system. This bundle has two member links: one active link and one inactive
link.
Router# show ppp multilink
Multilink1, bundle name is 7206-2
Endpoint discriminator is 7206-2
Bundle up for 00:00:15, 1/255 load
Receive buffer limit 12000 bytes, frag timeout 3428 ms
0/0 fragments/bytes in reassembly list
1 lost fragments, 1 reordered
0/0 discarded fragments/bytes, 0 lost received
0x3 received sequence, 0x3 sent sequence
Member links:1 active, 1 inactive (max not set, min not set)
Vi2, since 00:00:15, 105 weight, 93 frag size
Vt1 (inactive)
Where to Go Next
To use Multilink PPP over ATM links, see the "Using Multilink PPP over ATM Links" module.
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Using Multilink PPP over Frame Relay
Additional References
To use Multilink PPP over dialer interface links, see the "Using Multilink PPP over Dialer Interface Links"
module.
To use Multilink PPP over serial interface links, see the "Using Multilink PPP over Serial Interface Links"
module.
Additional References
The following sections provide references related to using Multilink PPP over Frame Relay.
Related Documents
Related Topic
Document Title
QoS commands: complete command syntax,
Cisco IOS Quality of Service Solutions Command
command modes, command history, defaults, usage Reference
guidelines, and examples
LLQ, WFQ, CBWFQ, PQ, CQ, FIFO and other
queueing mechanisms
"Configuring Weighted Fair Queueing" module
MQC
"Applying QoS Features Using the MQC" module
FRTS
"MQC-Based Frame Relay Traffic Shaping"
module
Multilink PPP configurations
"Configuring Media-Independent PPP and
Multilink PPP" module
Virtual template interfaces
"Configuring Virtual Template Interfaces" module
Multilink PPP overview module
"Reducing Latency and Jitter for Real-Time Traffic
Using Multilink PPP" module
Multilink PPP over ATM links (including ATM
interfaces and ATM PVCs)
"Using Multilink PPP over ATM Links" module
Multilink PPP over dialer interface links
"Using Multilink PPP over Dialer Interface Links"
module
Multilink PPP over serial interface links
"Using Multilink PPP over Serial Interface Links"
module
Standards
Standard
Title
No new or modified standards are supported, and
support for existing standards has not been
modified.
--
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Using Multilink PPP over Frame Relay
Feature Information for Using Multilink PPP over Frame Relay
MIBs
MIB
MIBs Link
No new or modified MIBs are supported, and
support for existing MIBs has not been modified.
To locate and download MIBs for selected
platforms, Cisco IOS releases, and feature sets, use
Cisco MIB Locator found at the following URL:
http://www.cisco.com/go/mibs
RFCs
RFC
Title
RFC 1990
The PPP Multilink Protocol (MP)
RFC 2686
Multiclass Extension to Multilink PPP (MCML)
Technical Assistance
Description
Link
The Cisco Support and Documentation website
provides online resources to download
documentation, software, and tools. Use these
resources to install and configure the software and
to troubleshoot and resolve technical issues with
Cisco products and technologies. Access to most
tools on the Cisco Support and Documentation
website requires a Cisco.com user ID and
password.
http://www.cisco.com/cisco/web/support/
index.html
Feature Information for Using Multilink PPP over Frame Relay
The following table provides release information about the feature or features described in this module.
This table lists only the software release that introduced support for a given feature in a given software
release train. Unless noted otherwise, subsequent releases of that software release train also support that
feature.
Use Cisco Feature Navigator to find information about platform support and Cisco software image support.
To access Cisco Feature Navigator, go to www.cisco.com/go/cfn. An account on Cisco.com is not required.
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Using Multilink PPP over Frame Relay
Table 3
Feature Information for Using Multilink PPP over Frame Relay
Feature Name
Software Releases
Feature Configuration Information
Distributed Link Fragmentation
and Interleaving for Frame Relay
and ATM Interfaces on Cisco
7500 Series Routers
12.2(4)T
The Distributed Link
Fragmentation and Interleaving
(dLFI) for Frame Relay and ATM
Interfaces on Cisco 7500 Series
Routers feature extends link
fragmentation and interleaving
functionality to VIP-enabled
Cisco 7500 series routers.
This feature was extensively
rewritten from the perspective of
using Multilink PPP for link
fragmentation and interleaving
over Frame Relay.
Distributed Link Fragmentation
and Interleaving Over Leased
Lines
12.2(8)T
The Distributed Link
Fragmentation and Interleaving
over Leased Lines feature extends
distributed link fragmentation and
interleaving functionality to
leased lines.
This feature was extensively
rewritten from the perspective of
using Multilink PPP for link
fragmentation and interleaving
over Frame Relay.
Cisco and the Cisco logo are trademarks or registered trademarks of Cisco and/or its affiliates in the U.S.
and other countries. To view a list of Cisco trademarks, go to this URL: www.cisco.com/go/trademarks.
Third-party trademarks mentioned are the property of their respective owners. The use of the word partner
does not imply a partnership relationship between Cisco and any other company. (1110R)
Any Internet Protocol (IP) addresses and phone numbers used in this document are not intended to be
actual addresses and phone numbers. Any examples, command display output, network topology diagrams,
and other figures included in the document are shown for illustrative purposes only. Any use of actual IP
addresses or phone numbers in illustrative content is unintentional and coincidental.
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Example Verifying the Multilink PPP over Frame Relay Configuration
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60
Using Multilink PPP over Serial Interface Links
This module contains conceptual information and configuration tasks for using Multilink PPP over serial
interface links. Multilink PPP is a method used to reduce latency and jitter for real-time traffic.
•
•
•
•
•
•
•
•
•
Finding Feature Information, page 61
Prerequisites for Using Multilink PPP over Serial Interface Links, page 61
Restrictions for Using Multilink PPP over Serial Interface Links, page 62
Information About Using Multilink PPP over Serial Interface Links, page 62
How to Configure Multilink PPP over Serial Interface Links, page 63
Configuration Examples for Using Multilink PPP over Serial Interface Links, page 68
Where to Go Next, page 70
Additional References, page 70
Feature Information for Using Multilink PPP over Serial Interface Links, page 71
Finding Feature Information
Your software release may not support all the features documented in this module. For the latest feature
information and caveats, see the release notes for your platform and software release. To find information
about the features documented in this module, and to see a list of the releases in which each feature is
supported, see the Feature Information Table at the end of this document.
Use Cisco Feature Navigator to find information about platform support and Cisco software image support.
To access Cisco Feature Navigator, go to www.cisco.com/go/cfn. An account on Cisco.com is not required.
Prerequisites for Using Multilink PPP over Serial Interface
Links
Knowledge
•
Be familiar with the concepts in the "Reducing Latency and Jitter for Real-Time Traffic Using
Multilink PPP" module.
Enable Queueing Mechanism
•
Multilink uses first-in first out (FIFO) queuing for queueing and interleaving packets. Other queueing
mechanisms such as low latency queueing (LLQ), weighted fair queueing (WFQ), and class-based
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MQC and Multilink PPP over Serial Interface Links
Restrictions for Using Multilink PPP over Serial Interface Links
weighted fair queueing (CBWFQ) can be used. If you want to use one of these alternative
mechanisms, enable it before configuring multilink.
Restrictions for Using Multilink PPP over Serial Interface
Links
Number of Links per Multilink Bundle
If a multilink bundle has one link or packet order is not important for interleaved packets, use Link
Fragmentation and Interleaving (LFI) without multiclass. Use LFI with multiclass if a multilink bundle has
multiple links.
VoIP Support
Only Voice over IP (VoIP) is supported.
Queueing Mechanisms Not Supported
Many of the legacy queueing mechanisms are not supported by multilink. These mechanisms include:
•
•
•
•
Note
Fair queueing on a virtual template interface
Weighted random early detection (WRED) on a virtual template interface
Custom queueing
Priority queueing
Fair queueing, WRED, and priority queueing can be configured in a traffic policy using the Modular
Quality of Service (QoS) Command-Line Interface (CLI) (MQC).
Information About Using Multilink PPP over Serial Interface
Links
•
•
MQC and Multilink PPP over Serial Interface Links, page 62
Multilink Group Interfaces, page 63
MQC and Multilink PPP over Serial Interface Links
Before using Multilink PPP over serial interface links, a traffic policy (also known as a policy map) must
be created. (See the MQC and Multilink PPP over Serial Interface Links, page 62.) Policy maps are created
using the Modular Quality of Service (QoS) Command-Line Interface (CLI) (MQC).
The MQC is a CLI structure that allows users to create traffic polices (policy maps) and attach these policy
maps to interfaces. A policy map contains a traffic class and one or more QoS features. A traffic class is
used to classify traffic. The QoS features in the traffic policy determine how to treat the classified traffic.
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Multilink Group Interfaces
How to Configure Multilink PPP over Serial Interface Links
Multilink Group Interfaces
A multilink group interface is a collection of interfaces bundled together in the multilink PPP
configuration. With a multilink group interface, you can bundle interfaces into logical multilink groups.
How to Configure Multilink PPP over Serial Interface Links
•
•
•
Configuring Multilink PPP over Serial Interface Links on a Multilink Group Interface, page 63
Associating the Serial Interface with the Multilink Group, page 65
Verifying the Multilink PPP over Serial Interface Link Configuration, page 67
Configuring Multilink PPP over Serial Interface Links on a Multilink Group
Interface
Before proceeding with this task, you must create a policy map. The policy map contains the configuration
parameters used to apply the specific quality of service feature to the network traffic. To create a policy
map, use the MQC. See the MQC and Multilink PPP over Serial Interface Links, page 62.
SUMMARY STEPS
1. enable
2. configure terminal
3. interface multilink multilink-bundle-number
4. ip address ip-address mask [secondary]
5. service-policy output policy-map-name
6. service-policy input policy-map-name
7. ppp multilink fragment delay milliseconds [microseconds]
8. ppp multilink interleave
9. ppp multilink multiclass
10. end
DETAILED STEPS
Command or Action
Step 1 enable
Purpose
Enables privileged EXEC mode.
•
Enter your password if prompted.
Example:
Router> enable
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Using Multilink PPP over Serial Interface Links
How to Configure Multilink PPP over Serial Interface Links
Command or Action
Step 2 configure terminal
Purpose
Enters global configuration mode.
Example:
Router# configure terminal
Step 3 interface multilink multilink-bundle-number
Creates a multilink bundle and enters interface configuration mode.
•
Enter the multilink bundle number.
Example:
Router(config)# interface multilink 1
Step 4 ip address ip-address mask [secondary]
Example:
Sets a primary IP address for an interface. This command can also set
the optional secondary IP address for an interface.
•
Enter the primary IP address (and, optionally, the secondary IP
address).
Router(config-if)# ip address
10.10.100.1 255.255.255.0
Step 5 service-policy output policy-map-name
Example:
Router(config-if)# service-policy
output policy1
Step 6 service-policy input policy-map-name
Example:
Router(config-if)# service-policy input
policy1
Step 7 ppp multilink fragment delay milliseconds
[microseconds]
Attaches the previously created QoS traffic policy (policy map). See
the Configuring Multilink PPP over Serial Interface Links on a
Multilink Group Interface, page 63. The policy map evaluates and
applies QoS features for traffic leaving the interface.
•
Enter the policy map name.
Attaches the previously created QoS traffic policy (policy map). See
the Configuring Multilink PPP over Serial Interface Links on a
Multilink Group Interface, page 63. The policy map evaluates and
applies QoS features for traffic enteringthe interface.
•
Enter the policy map name.
Specifies a maximum size in units of time for packet fragments on a
Multilink PPP (MLP) bundle.
•
Enter the maximum amount of time, in milliseconds.
Example:
Router(config-if)# ppp multilink
fragment delay 20
Step 8 ppp multilink interleave
Enables interleaving of packets among the fragments of larger packets
on a multilink bundle.
Example:
Router(config-if)# ppp multilink
interleave
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Associating the Serial Interface with the Multilink Group
How to Configure Multilink PPP over Serial Interface Links
Command or Action
Step 9 ppp multilink multiclass
Purpose
(Optional) Enables Multiclass Multilink PPP (MCMP) on an interface.
Note Use this command only if there are multiple links in the
multilink bundle.
Example:
Router(config-if)# ppp multilink
multiclass
Step 10 end
(Optional) Exits interface configuration mode.
Example:
Router(config-if)# end
Associating the Serial Interface with the Multilink Group
SUMMARY STEPS
1. enable
2. configure terminal
3. interface serial slot / port : timeslot
4. no fair-queue
5. encapsulation ppp
6. ppp multilink
7. ppp multilink group group-number
8. end
DETAILED STEPS
Command or Action
Step 1 enable
Purpose
Enables privileged EXEC mode.
•
Enter your password if prompted.
Example:
Router> enable
Step 2 configure terminal
Enters global configuration mode.
Example:
Router# configure terminal
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Using Multilink PPP over Serial Interface Links
How to Configure Multilink PPP over Serial Interface Links
Command or Action
Step 3 interface serial slot / port : timeslot
Example:
Purpose
Specifies a serial interface created on a channelized E1 or channelized
T1 controller (for ISDN PRI, channel-associated signaling, or robbed-bit
signaling), and enters interface configuration mode.
•
Router# interface serial 4/1:23
Enter the slot number and port number where the channelized E1 or
T1 controller is located.
Example:
Step 4 no fair-queue
Disables WFQ (or DWFQ for VIP-enabled routers).
Example:
Router(config-if)# no fair-queue
Step 5 encapsulation ppp
Sets the serial interface encapsulation method used by the interface.
Example:
Router(config-if)# encapsulation ppp
Step 6 ppp multilink
Enables Multilink on an interface.
Example:
Router(config-if)# ppp multilink
Step 7 ppp multilink group group-number
Example:
Restricts a physical link to joining only a designated multilink group
interface.
•
Enter the multilink group number.
Router(config-if)# ppp multilink group 1
Step 8 end
(Optional) Exits interface configuration mode.
Example:
Router(config-if)# end
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Verifying the Multilink PPP over Serial Interface Link Configuration
How to Configure Multilink PPP over Serial Interface Links
Verifying the Multilink PPP over Serial Interface Link Configuration
SUMMARY STEPS
1. enable
2. show interfaces [type number] [first] [last] [accounting]
3. show ppp multilink [active | inactive | interface bundle-interface | [username name] [endpoint
endpoint]]
4. show policy-map interface interface-name [vc [vpi/] vci] [dlci dlci] [input | output]
5. exit
DETAILED STEPS
Command or Action
Purpose
Step 1 enable
Enables privileged EXEC mode.
•
Enter your password if prompted.
Example:
Router> enable
Step 2 show interfaces [type number] [first] [last] [accounting]
(Optional) Displays statistics for all interfaces configured
on the router or access server.
Example:
Router# show interfaces
Step 3 show ppp multilink [active | inactive | interface bundleinterface | [username name] [endpoint endpoint]]
(Optional) Displays bundle information for mutlilink
bundles.
Example:
Router# show ppp multilink
Step 4 show policy-map interface interface-name [vc [vpi/] vci]
[dlci dlci] [input | output]
(Optional) Displays the packet statistics of all classes that
are configured for all service policies either on the specified
interface or subinterface or on a specific permanent virtual
circuit (PVC) on the interface.
Example:
Router# show policy-map interface serial0/0
Step 5 exit
(Optional) Exits privileged EXEC mode.
Example:
Router# exit
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Configuring Multilink PPP over Serial Interface Links on a Multilink Group Interface Example
Configuration Examples for Using Multilink PPP over Serial Interface Links
Configuration Examples for Using Multilink PPP over Serial
Interface Links
• Configuring Multilink PPP over Serial Interface Links on a Multilink Group Interface Example, page
68
• Associating the Serial Interface with the Multilink Group Example, page 69
• Verifying the Multilink PPP over Serial Interface Link Configuration Example, page 69
Configuring Multilink PPP over Serial Interface Links on a Multilink Group
Interface Example
The following is an example of configuring Multilink PPP over serial interface links on a multilink group
interface:
Router>
enable
Router#
configure terminal
Router(config)#
interface multilink 1
Router(config-if)# ip address 10.10.100.1 255.255.255.0
Router(config-if)#
service-policy output policy1
Router(config-if)#
service-policy input policy1
Router(config-if)#
ppp multilink fragment delay 20
Router(config-if)#
ppp multilink interleave
Router(config-if)#
ppp multilink multiclass
Router(config-if)#
end
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Associating the Serial Interface with the Multilink Group Example
Configuration Examples for Using Multilink PPP over Serial Interface Links
Associating the Serial Interface with the Multilink Group Example
The following is an example of associating the serial interface serial4/1 with the multilink group:
Router>
enable
Router#
configure terminal
Router(config)#
interface serial 4/1:23
Router(config-if)#
no fair-queue
Router(config-if)#
encapsulation ppp
Router(config-if)#
ppp multilink
Router(config-if)#
ppp multilink group 1
Router(config-if)#
end
Verifying the Multilink PPP over Serial Interface Link Configuration
Example
You can verify the Multilink PPP over serial interface links configuration by using one or more of the
following show commands:
•
•
•
show interfaces
show ppp multilink
show policy-map interface
The following section provides sample output of the show ppp multilink command only. For sample
output of the other commands, see the appropriate Cisco IOS Release 12.3 T command reference
publication.
show ppp multilink Command Output Example
The following is an example of the show ppp multilink command output. In this example, one multilink
bundle called 7206-2 is on the system. This bundle has two member links: one active link and one inactive
link.
Router# show ppp multilink
Multilink2, bundle name is 7206-2
Endpoint discriminator is 7206-2
Bundle up for 00:00:09, 1/255 load
Receive buffer limit 12000 bytes, frag timeout 1500 ms
0/0 fragments/bytes in reassembly list
0 lost fragments, 0 reordered
0/0 discarded fragments/bytes, 0 lost received
0x0 received sequence, 0x3 sent sequence
Member links:1 active, 1 inactive (max not set, min not set)
Se3/2, since 00:00:10, 240 weight, 232 frag size
Se3/3 (inactive)
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Using Multilink PPP over Serial Interface Links
Where to Go Next
Where to Go Next
To use Multilink PPP over ATM links, see the "Using Multilink PPP over ATM Links" module.
To use Multilink PPP over Frame Relay, see the "Using Multilink PPP over Frame Relay" module.
To use Multilink PPP over dialer interface links, see the "Using Multilink PPP over Dialer Interface Links"
module.
Additional References
The following sections provide references related to Multilink PPP over serial interface links:
Related Documents
Related Topic
Document Title
QoS commands: complete command syntax,
Cisco IOS Quality of Service Solutions Command
command modes, command history, defaults, usage Reference
guidelines, and examples
LLQ, WFQ, CBWFQ, PQ, CQ, FIFO and other
queueing mechanisms
"Configuring Weighted Fair Queueing" module
MQC
"Applying QoS Features Using the MQC" module
Multilink PPP configurations
"Configuring Media-Independent PPP and
Multilink PPP" module
Multilink PPP overview module
"Reducing Latency and Jitter for Real-Time Traffic
Using Multilink PPP" module
Multilink PPP over ATM links (including ATM
interfaces and ATM PVCs)
"Using Multilink PPP over ATM Links" module
Multilink PPP over Frame Relay
"Using Multilink PPP over Frame Relay" module
Multilink PPP over dialer interface links
"Using Multilink PPP over Dialer Interface Links"
module
Standards
Standard
Title
No new or modified standards are supported, and
support for existing standards has not been
modified.
--
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Using Multilink PPP over Serial Interface Links
Feature Information for Using Multilink PPP over Serial Interface Links
MIBs
MIB
MIBs Link
No new or modified MIBs are supported, and
support for existing MIBs has not been modified.
To locate and download MIBs for selected
platforms, Cisco IOS releases, and feature sets, use
Cisco MIB Locator found at the following URL:
http://www.cisco.com/go/mibs
RFCs
RFC
Title
RFC 1990
The PPP Multilink Protocol (MP)
RFC 2686
Multiclass Extension to Multilink PPP (MCML)
Technical Assistance
Description
Link
The Cisco Support and Documentation website
provides online resources to download
documentation, software, and tools. Use these
resources to install and configure the software and
to troubleshoot and resolve technical issues with
Cisco products and technologies. Access to most
tools on the Cisco Support and Documentation
website requires a Cisco.com user ID and
password.
http://www.cisco.com/cisco/web/support/
index.html
Feature Information for Using Multilink PPP over Serial
Interface Links
The following table provides release information about the feature or features described in this module.
This table lists only the software release that introduced support for a given feature in a given software
release train. Unless noted otherwise, subsequent releases of that software release train also support that
feature.
Use Cisco Feature Navigator to find information about platform support and Cisco software image support.
To access Cisco Feature Navigator, go to www.cisco.com/go/cfn. An account on Cisco.com is not required.
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Using Multilink PPP over Serial Interface Links
Table 4
Feature Information for Using Multilink PPP over Serial Interface Links
Feature Name
Software Releases
Feature Configuration Information
Distributed Link Fragmentation
and Interleaving Over Leased
Lines
12.2(8)T
The Distributed Link
Fragmentation and Interleaving
over Leased Lines feature extends
distributed link fragmentation and
interleaving functionality to
leased lines.
This feature was extensively
rewritten from the perspective of
using Multilink PPP for link
fragmentation and interleaving
over serial interface links.
Distributed Link Fragmentation
and Interleaving for Frame Relay
and ATM Interfaces on Cisco
7500 Series Routers
12.2(4)T
The Distributed Link
Fragmentation and Interleaving
(dLFI) for Frame Relay and ATM
Interfaces on Cisco 7500 Series
Routers feature extends link
fragmentation and interleaving
functionality to VIP-enabled
Cisco 7500 series routers.
This feature was extensively
rewritten from the perspective of
using Multilink PPP for link
fragmentation and interleaving
over serial interface links.
Cisco and the Cisco logo are trademarks or registered trademarks of Cisco and/or its affiliates in the U.S.
and other countries. To view a list of Cisco trademarks, go to this URL: www.cisco.com/go/trademarks.
Third-party trademarks mentioned are the property of their respective owners. The use of the word partner
does not imply a partnership relationship between Cisco and any other company. (1110R)
Any Internet Protocol (IP) addresses and phone numbers used in this document are not intended to be
actual addresses and phone numbers. Any examples, command display output, network topology diagrams,
and other figures included in the document are shown for illustrative purposes only. Any use of actual IP
addresses or phone numbers in illustrative content is unintentional and coincidental.
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