Table Of Contents

FRF .20 Support

Contents

Prerequisites for FRF .20 Support

Restrictions for FRF .20 Support

Information About FRF .20 Support

IP Header Compression

Enhanced Compressed Real-Time Transport Protocol

How to Configure FRF .20 Support

Configuring FRF .20 Support Using Profiles

Configuring an IPHC for Frame Relay Profile to a Map Class

Prerequisite

Configuring FRF .20 Support on VC Bundles

Configuring FRF .20 Support on VC Bundles Using the Map Command

Configuring FRF .20 Support on a PVC Using the Class Command

Enabling ECRTP

Displaying Frame Relay Profile Status

Configuration Examples for FRF .20 Support

Adding an IPHC Profile to a Map Class

Additional References

Related Documents

Standards

MIBs

RFCs

Technical Assistance

Command Reference

Feature Information for FRF .20 Support

FRF .20 Support

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First Published: June 19, 2006

Last Updated: November 17, 2006

The FRF .20 Support feature provides support for IP header compression (IPHC) over Frame Relay as described in the Frame Relay Forum Implementation Agreement FRF .20. Before the FRF .20 Support feature was introduced, Cisco IOS supported IPHC only on Cisco-encapsulated data-link connection identifiers (DLCIs) using a proprietary compression technique. This feature adds support for IPHC on IETF-encapsulated DLCIs.

This feature module describes how to configure FRF .20 IPHC over Frame Relay. This feature module also describes how to configure Enhanced Compressed Real-Time Transport Protocol (ECRTP).

Finding Feature Information in This Module

Your Cisco IOS software release may not support all of the features documented in this module. To reach links to specific feature documentation in this module and to see a list of the releases in which each feature is supported, use the "Feature Information for FRF .20 Support" section.

Finding Support Information for Platforms and Cisco IOS Software Images

Use Cisco Feature Navigator to find information about platform support and Cisco IOS software image support. Access Cisco Feature Navigator at http://www.cisco.com/go/fn. You must have an account on Cisco.com. If you do not have an account or have forgotten your username or password, click Cancel at the login dialog box and follow the instructions that appear.

Contents

•Prerequisites for FRF .20 Support

•Restrictions for FRF .20 Support

•Information About FRF .20 Support

•How to Configure FRF .20 Support

•Configuration Examples for FRF .20 Support

•Additional References

•Command Reference

•Feature Information for FRF .20 Support

Prerequisites for FRF .20 Support

You should understand the concepts and general configuration procedures for IP header compression. For information about IP header compression, see the Configuring Header Compression Using IPHC Profiles chapter in the Cisco IOS Quality of Service Solutions Configuration Guide.

Restrictions for FRF .20 Support

After a map class containing an IPHC profile is applied to an interface, subsequent attempts (using the frame-relay ip rtp header-compression command) to apply Real-time Transport Protocol (RTP) header compression for all Frame Relay maps on a physical interface are blocked.

Information About FRF .20 Support

To configure FRF .20 support, you should understand the following concept:

•IP Header Compression

•Enhanced Compressed Real-Time Transport Protocol

IP 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 either RTP or Transmission Control Protocol (TCP) packets. With IPHC over Frame Relay, compression parameters are negotiated across a DLCI.

One method of configuring header compression on your network is to use an IPHC profile. An IPHC profile is a kind of template within which you can configure the type of header compression that you want to use, set all of the optional features and parameters for header compression, and then apply the profile to an interface, subinterface, or Frame Relay permanent virtual circuit (PVC).

Enhanced Compressed Real-Time Transport Protocol

ECRTP is robust over links that are susceptible to frame loss. Header compression happens early in the Cisco Express Forwarding (CEF) switching path before queueing. If an interface or PVC is oversubscribed, all the dropped frames are compressed frames, which can impact CRTP compression performance. Using ECRTP can minimize the problem, because it provides better error recovery.

How to Configure FRF .20 Support

The following sections describe how to configure IPHC for FRF .20 over Frame Relay.

•Configuring FRF .20 Support Using Profiles

•Configuring an IPHC for Frame Relay Profile to a Map Class

•Configuring FRF .20 Support on VC Bundles

•Enabling ECRTP (optional)

•Displaying Frame Relay Profile Status (optional)

Configuring FRF .20 Support Using Profiles

To enable FRF .20 support on a DLCI, you attach an IPHC profile to a map class.

Restrictions

A map class containing a profile cannot overlap either an interface configuration or a PVC-level legacy configuration.

SUMMARY STEPS

1. enable

2. configure terminal

3. iphc-profile profile-name ietf

4. tcp

5. non-tcp contexts absolute number-of-contexts

6. rtp

7. class-map type traffic match-any class-map-name

8. match [ip] precedence precedence-value

9. map-class frame-relay map-class-name

10. iphc-profile profile-name

11. 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	iphc-profile profile-name ietf Example: Router(config)# iphc-profile profile100 ietf	Creates an IPHC profile and enter the IPHC-profile configuration mode. •profile-name—Name of the IPHC profile you are creating. The name can be a maximum of 40 alphanumeric characters. •ietf—IPHC profile type. Conforms with standards for FRF .20
Step 4	tcp Example: Router(config-iphcp)# tcp	(Optional) Enables TCP header compression.
Step 5	non-tcp contexts absolute number-of-contexts Example: Router(config-iphcp)# non-tcp contexts absolute 60	(Optional) Enables non-Transmission-Control-Protocol (TCP) header compression within an IPHC profile. This is required when RTP is configured.
Step 6	rtp Example: Router(config-iphcp)# rtp	(Optional) Enables RTP header compression within an IPHC profile.
Step 7	class-map type traffic match-any class-map-name Example: Router(config-iphcp)# class-map type traffic match-any class100	Creates a traffic class map, which is used for matching packets to a specified traffic class and enters class-map configuration mode. •match-any—Indicates that packets must meet one of the match criteria in order to be considered a member of the class. •class-map-name—Name of the class map.
Step 8	match [ip] precedence precedence-value Example: Router(config-cmap)# match ip precedence 1	Identifies the IP precedence values as match criteria. •ip—(Optional) Specifies that the match is for IPv4 packets only. If not used, the match is on both IP and IPv6 packets. •precedence-value—Specifies the exact value from 0 to 7 used to identify a precedence value.
Step 9	map-class frame-relay map-class-name Example: Router(config-map-class)# compress header rtp	Creates a Frame Relay map class and enters the static map class configuration mode.
Step 10	iphc-profile profile-name Example: Router(config)# iphc-profile profile100 ietf	Creates an IPHC profile. •profile-name—Name of the IPHC profile you are creating. The name can be a maximum of 40 alphanumeric characters.
Step 11	end Example: Router(config-map-class)# end	Ends the configuration session and returns to privileged EXEC mode.

Configuring an IPHC for Frame Relay Profile to a Map Class

You can use these procedures to configure an IPHC profile directly to a map class. You then apply the map class to the interface or DLCI directly. When the map class is applied, FRF .20 negotiation is started across the DILL, and IPHC is started.

Prerequisite

Before FRF .20 negotiation can start, the PVC must be active.

SUMMARY STEPS

1. enable

2. configure terminal

3. map-class frame-relay map-class-name

4. frame-relay iphc-profile profile-name

5. exit

6. frame-relay class class-name

7. frame-relay interface-dlci dlci

8. class class-name

9. 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	map class frame-relay map-class-name Example: Router(config)# map class frame-relay mapclass100	Creates a map class and enters static map class configuration mode. •map-class-name—Name of the map class. The name can be a maximum of 40 alphanumeric characters.
Step 4	frame-relay iphc-profile profile-name Example: Router(config-map-class)# frame-relay iphc-profile profile100	Attaches the IPHC profile to the Frame Relay map class. Enter the name of the IPHC profile that is to be attached to the Frame Relay map class created in Step 3.
Step 5	exit Example: Router(config-map-class)# exit	Exits static map class configuration mode.
Step 6	frame-relay class class-name Example: Router(config)# frame-relay class frclass100	Creates a Frame Relay class and enters Frame Relay class configuration mode.
Step 7	frame-relay interface-dlci dlci Example: Router(config-fr-class)# frame-relay interface-dlci dlci 100	Assigns a data-link connection identifier (DLCI) to a specified Frame Relay interface on the router or access server, and enters Frame Relay DLCI configuration mode. •dlci—DLCI number for the interface
Step 8	class class-name Example: Router(config-fr-dlci)# class mapclass100	Associates a map class with a specified DLCI. Enter the name of the map class to associate with the DLCI.
Step 9	end Example: Router(config-pmap-c)# end	Ends the configuration session and returns to privileged EXEC mode.

Configuring FRF .20 Support on VC Bundles

IPHC can be configured on virtual circuit (VC) bundles using the map command either on the bundle itself or on individual PVCs within the VC bundle using the map-class command.

You cannot enable IPHC in both places at the same time, because the map command is inherited by all the PVCs in the same bundle.

The following sections describe both methods of configuring FRF .20 support on VC bundles.|

Configuring FRF .20 Support on VC Bundles Using the Map Command

To enable FRF .20 support on VC bundles using the map command, complete the following steps.

SUMMARY STEPS

1. enable

2. configure terminal

3. frame-relay map ip-address vc-bundle vc-bundle-name [rtp | tcp] header-compression

4. 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	frame-relay map ip ip-address vc-bundle vc-bundle-name [rtp | tcp] header-compression Example: Router(config)# frame-relay map ip 209.165.200.230 vc-bundle test rtp header-compression	Enables header compression on VC bundles.
Step 4	end Example: Router(config)# end	Ends the configuration session and returns to privileged EXEC mode.

Configuring FRF .20 Support on a PVC Using the Class Command

To enable FRF .20 support on a PVC using the class command, complete the following steps.

SUMMARY STEPS

1. enable

2. configure terminal

3. frame-relay vc-bundle vc-bundle-name

4. pvc name

5. class class-name

6. end

DETAILED STEPS

	Command or Action	Purpose
Step 1	enable Example: Router> enable	Enables privileged EXEC mode. •Enter your password if prompted.
Step 2	frame-relay vc-bundle vc-bundle-name Example: Router(config)#frame-relay vc-bundle vcbundle100	Creates a Frame Relay permanent virtual circuit (PVC) bundle if it does not already exist, and enters Frame Relay VC-bundle configuration mode.
Step 3	pvc name Example: Router(config fr-vcbundle)# frame-relay vc-bundle vcbundle100	Creates or assigns a name to a permanent virtual circuit (PVC).
Step 4	class class-name Example: Router(config-fr-vcbundle)# class mapclass100	Associates a map class with a specified DLCI. Enter the name of the map class to associate with the DLCI.
Step 5	end Example: Router(config-fr-vcbundle)# end	Ends the configuration session and returns to privileged EXEC mode.

Enabling ECRTP

To enable ECRTP on an interface, use the following steps.

SUMMARY STEPS

1. enable

2. configure terminal

3. interface type number

4. iphc-profile profile-name ietf

5. non-tcp

6. rtp

7. recoverable-loss {dynamic | packet-drops}

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 type number Example: Router(config)# interface serial 3/0	Configures an interface type and enters interface configuration mode.
Step 4	iphc-profile profile-name ietf Example: Router(config-if)# iphc-profile profile100 ietf	Attaches an existing IPHC profile to an interface and enters the IPHC-profile configuration mode. •profile-name—Name of the IPHC profile you are attaching to the interface. ietf—IPHC profile type. Conforms with standards for FRF .20
Step 5	non-tcp Example: Router(config-iphcp)# non-tcp	Enables non-Transmission-Control-Protocol (TCP) header compression within an IPHC profile.
Step 6	rtp Example: Router(config-iphcp)# rtp	(Optional) Enables RTP header compression within an IPHC profile.
Step 7	recoverable-loss {dynamic | packet-drops} Example: Router(config-iphcp)# recoverable-loss dynamic	Enables ECRTP on an interface.
Step 8	end Example: Router(config-iphcp)# end	Ends the configuration session and returns to privileged EXEC mode.

Displaying Frame Relay Profile Status

You can display the current Frame Relay map entries and information about connections. To display active Frame Relay information, perform the following optional steps.

SUMMARY STEPS

1. enable

2. show frame-relay map [interface type number] [dlci]

3. end

DETAILED STEPS

	Command or Action	Purpose
Step 1	enable Example: Router> enable	Enables privileged EXEC mode. •Enter your password if prompted.
Step 2	show frame-relay map [interface type number] [dlci] Example: Router# show frame-relay map 20	Displays current Frame Relay map entries and information about connections. •interface type number—(Optional) Specifies an interface for which mapping information will be displayed. A space is optional between the interface type and number. •dlci—(Optional) Specifies a data-link connection identifier (DLCI) for which mapping information will be displayed. Range: 16 to 1022.
Step 3	end Example: Router# end	Ends the configuration session and returns to privileged EXEC mode.

Configuration Examples for FRF .20 Support

This section provides the following example:

•Adding an IPHC Profile to a Map Class

Adding an IPHC Profile to a Map Class

The following example shows how to add an IPHC profile to a Frame Relay map class. In this configuration, a profile is created using the iphc-profile command in global command mode. The profile is then attached to a Frame Relay map class.

Router> enable

Router# configure terminal

Enter configuration commands, one per line. End with CNTL/Z.

Router(config)# iphc-profile iphc ietf

Router(config-iphcp)# tcp

Router(config-iphcp)# rtp

For non-TCP configuration, you must also configure the following:

Router(config-iphcp)# exit

Router(config)# map-class frame frf20

Router(config-map-class)# frame iphc

Router(config-map-class)# frame iphc-profile iphc

Router(config-map-class)# end

Additional References

The following sections provide references related to the FRF .20 Support feature.

Related Documents

Related Topic	Document Title
IPHC information and configuration tasks	Cisco IOS Quality of Service Solutions Configuration Guide
Additional QoS commands	Cisco IOS Quality of Service Solutions Command Reference

Standards

Standard	Title
FRF .20	Frame Relay IP Header Compression Implementation Agreement

MIBs

MIB	MIBs Link
None	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 3545	Enhanced Compressed RPT for Links with High Delay, Packet Loss and Reordering

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/cisco/web/support/index.html

Command Reference

The following commands are introduced or modified in the feature or features documented in this module. For information about these commands, see the Cisco IOS Wide-Area Networking Command Reference at http://www.cisco.com/en/US/docs/ios/wan/command/reference/wan_book.html. For information about all Cisco IOS commands, go to the Command Lookup Tool at http://tools.cisco.com/Support/CLILookup or to the Cisco IOS Master Commands List.

•debug frame-relay ip tcp header-compression

•iphc-profile

•non-tcp

•recoverable-loss

•rtp

•show frame-relay ip rtp header-compression

•show frame-relay map

Feature Information for FRF .20 Support

Table 1 lists the release history for this feature.

Not all commands may be available in your Cisco IOS software release. For release information about a specific command, see the command reference documentation.

Cisco IOS software images are specific to a Cisco IOS software release, a feature set, and a platform. Use Cisco Feature Navigator to find information about platform support and Cisco IOS software image support. Access Cisco Feature Navigator at http://www.cisco.com/go/fn. You must have an account on Cisco.com. If you do not have an account or have forgotten your username or password, click Cancel at the login dialog box and follow the instructions that appear.Table 1 lists only the Cisco IOS software release that introduced support for a given feature in a given Cisco IOS software release train. Unless noted otherwise, subsequent releases of that Cisco IOS software release train also support that feature.

Table 1

Feature Name	Releases	Feature Information
FRF .20 Support	12.4(9)T 12.4(11)T	This feature provides support for FRF .20. Support for IETF encapsulated DLCIs is also provided with this feature. In Cisco IOS Release 12.4(11)T, support for ECRTP was added, and the ability to enable IPHC on a specific PVC was added.

Feature Information for IP Header Compression Over Frame Relay

Any Internet Protocol (IP) addresses used in this document are not intended to be actual addresses. Any examples, command display output, and figures included in the document are shown for illustrative purposes only. Any use of actual IP addresses in illustrative content is unintentional and coincidental.

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