Cisco IOS XE Quality of Service Solutions Configuration Guide, Release 2 - Using Multilink PPP over Serial Interface Links [Cisco IOS XE Software]

Table Of Contents

Using Multilink PPP over Serial Interface Links

Finding Feature Information in This Module

Contents

Prerequisites for Using Multilink PPP over Serial Interface Links

Restrictions for Using Multilink PPP over Serial Interface Links

Information About Using Multilink PPP over Serial Interface Links

MQC and Multilink PPP over Serial Interface Links

How to Configure Multilink PPP over Serial Interface Links

Configuring Multilink PPP over Serial Interface Links on a Multilink Group Interface

Prerequisites

Associating the Serial Interface with the Multilink Group

Verifying the Multilink PPP over Serial Interface Link Configuration

Configuration Examples for Using Multilink PPP over Serial Interface Links

Configuring Multilink PPP over Serial Interface Links on a Multilink Group Interface: Example

Associating the Serial Interface with the Multilink Group: Example

Verifying the Multilink PPP over Serial Interface Link Configuration: Example

Additional References

Related Documents

Standards

MIBs

RFCs

Technical Assistance

Feature Information for Using Multilink PPP over Serial Interface Links

Glossary

Using Multilink PPP over Serial Interface Links

First Published: May 2, 2005

Last Updated: March 2, 2009

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 serial interface links.

Note As of Cisco IOS XE Software Release 2.1, Multilink PPP over serial interface links is the only Multilink PPP type supported. Multiclass MLPPP is not supported.

Finding Feature Information 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 for Using Multilink PPP over Serial Interface Links" section.

Use Cisco Feature Navigator to find information about platform support and Cisco IOS XE Software image support. To access Cisco Feature Navigator, go to http://www.cisco.com/go/cfn. An account on Cisco.com is not required.

Contents

•Prerequisites for Using Multilink PPP over Serial Interface Links

•Restrictions for Using Multilink PPP over Serial Interface Links

•Information About Using Multilink PPP over Serial Interface Links

•How to Configure Multilink PPP over Serial Interface Links

•Configuration Examples for Using Multilink PPP over Serial Interface Links

•Additional References

•Feature Information for Using Multilink PPP over Serial Interface Links

•Feature Information for Using Multilink PPP over Serial Interface Links

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.

Queueing Mechanism

Enable a queueing mechanism such as low latency queueing (LLQ), weighted fair queueing (WFQ), class-based WFQ (CBWFQ) and Weighted Random Early Detection (WRED), as applicable, 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.

Multilink PPP Types Supported

As of Cisco IOS XE Release 2.1, Multilink PPP over serial interface links is the only Multilink PPP type supported. Multiclass MLPPP is not supported.

Information About Using Multilink PPP over Serial Interface Links

To use Multilink PPP over serial interface links, you should understand the following concept:

•MQC and Multilink PPP over Serial Interface Links

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 "Prerequisites" section.) 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.

For more information about MQC, see the "Applying QoS Features Using the MQC" module.

How to Configure Multilink PPP over Serial Interface Links

This section contains the following procedures:

•Configuring Multilink PPP over Serial Interface Links on a Multilink Group Interface (required)

•Associating the Serial Interface with the Multilink Group (required)

•Verifying the Multilink PPP over Serial Interface Link Configuration (optional)

Configuring Multilink PPP over Serial Interface Links on a Multilink Group Interface

To configure Multilink PPP over serial interface links on a multilink group interface, complete the following steps.

Prerequisites

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. For more information about the MQC, see the "Applying QoS Features Using the MQC" module.

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

Purpose

Step 1

enable
Example:

Router> enable

Enables privileged EXEC mode.

•Enter your password if prompted.

Step 2

configure terminal
Example:

Router# configure terminal

Enters global configuration mode.

Step 3

interface multilink multilink-bundle-number
Example:

Router(config)# interface multilink 1

Creates a multilink bundle and enters interface configuration mode.

•Enter the multilink bundle number.
Step 4
ip address ip-address mask [secondary] 
Example:
Router(config-if)# ip address 10.10.100.1 
255.255.255.0 
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).
Step 5
service-policy output policy-map-name
Example:

Router(config-if)# service-policy output policy1
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.
Step 6
service-policy input policy-map-name
Example:

Router(config-if)# service-policy input policy1
Attaches the previously created QoS traffic policy (policy map). The policy map evaluates and applies QoS features for traffic entering the interface.

•Enter the policy map name.
Step 7

ppp multilink fragment delay milliseconds [microseconds]
Example:

Router(config-if)# ppp multilink fragment delay 20

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.

Step 8

ppp multilink interleave
Example:

Router(config-if)# ppp multilink interleave

Enables interleaving of packets among the fragments of larger packets on a multilink bundle.

Step 9

ppp multilink multiclass
Example:

Router(config-if)# ppp multilink multiclass

(Optional) Enables Multiclass Multilink PPP (MCMP) on an interface.

Note Use this command only if there are multiple links in the multilink bundle.

Step 10

end
Example:

Router(config-if)# end

(Optional) Exits interface configuration mode.
Associating the Serial Interface with the Multilink Group

To associate the serial interface with the multilink group, complete the following steps.

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

Purpose

Step 1

enable
Example:

Router> enable

Enables privileged EXEC mode.

•Enter your password if prompted.

Step 2

configure terminal
Example:

Router# configure terminal

Enters global configuration mode.
Step 3
interface serial slot/port:timeslot
Example:

Router# interface serial 4/1:23
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.

•Enter the slot number and port number where the channelized E1 or T1 controller is located.
Step 4

no fair-queue
Example:

Router(config-if)# no fair-queue

Disables WFQ.

Step 5

encapsulation ppp
Example:

Router(config-if)# encapsulation ppp

Sets the serial interface encapsulation method used by the interface.

Step 6

ppp multilink
Example:

Router(config-if)# ppp multilink

Enables Multilink on an interface.

Step 7

ppp multilink group group-number
Example:

Router(config-if)# ppp multilink group 1

Restricts a physical link to joining only a designated multilink group interface.

•Enter the multilink group number.

Step 8

end
Example:

Router(config-if)# end

(Optional) Exits interface configuration mode.
Verifying the Multilink PPP over Serial Interface Link Configuration

To verify the Multilink PPP over serial interface link configuration, complete the following steps.

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
Example:

Router> enable

Enables privileged EXEC mode.

•Enter your password if prompted.
Step 2
show interfaces [type number] [first] [last] 
[accounting] 
Example:

Router# show interfaces
(Optional) Displays statistics for all interfaces configured on the router or access server.
Step 3
show ppp multilink [active | inactive | 
interface bundle-interface | [username name] 
[endpoint endpoint]] 
Example:

Router# show ppp multilink
(Optional) Displays bundle information for mutlilink bundles.
Step 4
show policy-map interface interface-name [vc 
[vpi/] vci] [dlci dlci] [input | output] 
Example:

Router# show policy-map interface serial0/0/0
(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.
Step 5

exit
Example:

Router# exit

(Optional) Exits privileged EXEC mode.
Configuration Examples for Using Multilink PPP over Serial Interface Links

This section contains the following examples:

•Configuring Multilink PPP over Serial Interface Links on a Multilink Group Interface: Example

•Associating the Serial Interface with the Multilink Group: Example

•Verifying the Multilink PPP over Serial Interface Link Configuration: Example

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
Associating the Serial Interface with the Multilink Group: Example

The following is an example of associating serial interface 4/1 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 Cisco IOS Quality of Service Solutions Command Reference.

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 bundle-1 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 bundle-1
  Endpoint discriminator is bundle-1
  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)
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, command modes, command history, defaults, usage guidelines, and examples

Cisco IOS Quality of Service Solutions Command Reference

MQC

"Applying QoS Features Using the MQC" module

Multilink PPP overview

"Reducing Latency and Jitter for Real-Time Traffic Using Multilink PPP" 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 XE Software 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)

Technical Assistance

Description

Link

The Cisco Support website provides extensive online resources, including documentation and tools for troubleshooting and resolving technical issues with Cisco products and technologies.

To receive security and technical information about your products, you can subscribe to various services, such as the Product Alert Tool (accessed from Field Notices), the Cisco Technical Services Newsletter, and Really Simple Syndication (RSS) Feeds.

Access to most tools on the Cisco Support website requires a Cisco.com user ID and password.

http://www.cisco.com/techsupport

Feature Information for Using Multilink PPP over Serial Interface Links

Table 1 lists the release history for this feature.

Use Cisco Feature Navigator to find information about platform support and software image support. Cisco Feature Navigator enables you to determine which Cisco IOS XE Software images support a specific software release, feature set, or platform. To access Cisco Feature Navigator, go to http://www.cisco.com/go/cfn. An account on Cisco.com is not required.

Note Table 1 lists only the Cisco IOS XE Software release that introduced support for a given feature in a given Cisco IOS XE Software release train. Unless noted otherwise, subsequent releases of that Cisco IOS XE Software release train also support that feature.

Table 1 Feature Information for Using Multilink PPP over Serial Interface Links

Feature Name

Software Releases

Feature Configuration Information

MLPPP QoS (CBWFQ, LLQ, WRED)

Cisco IOS XE Release 2.1

The MLPPP QoS feature implements Multilink PPP (MLPPP) using a distributed hierarchical queueing framework (HQF). The MLPPP QoS feature incorporates class-based weighted fair queueing (CBWFQ), low latency queueing (LLQ), and weighted random early detection (WRED) functionality.

The following sections provide information about this feature:

•Information About Using Multilink PPP over Serial Interface Links

•How to Configure Multilink PPP over Serial Interface Links

Glossary

Multilink group interfaces—A collection of interfaces bundled together in the multilink PPP configuration. With a multilink group interface, you can bundle interfaces into logical multilink groups

PVC—permanent virtual circuit (or connection). Virtual circuit that is permanently established. PVCs save bandwidth associated with circuit establishment and teardown in situations where certain virtual circuits must exist all the time. In ATM terminology, called a permanent virtual connection.

virtual template interface—A 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 XE interface commands that are applied to virtual access interfaces, as needed.

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