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Table Of Contents
Prerequisites for FRF .20 Support
Restrictions for FRF .20 Support
Information About FRF .20 Support
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
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
Displaying Frame Relay Profile Status
Configuration Examples for FRF .20 Support
Adding an IPHC Profile to a Map Class
Feature Information for FRF .20 Support
FRF .20 Support
First Published: June 19, 2006Last Updated: November 17, 2006The 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
•
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:
•
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.
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Configuring FRF .20 Support Using Profiles
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Configuring an IPHC for Frame Relay Profile to a Map Class
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Configuring FRF .20 Support on VC Bundles
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Enabling ECRTP (optional)
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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
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
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
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
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
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
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)#rtpFor 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)#endAdditional References
The following sections provide references related to the FRF .20 Support feature.
Related Documents
Related Topic Document TitleIPHC information and configuration tasks
Cisco IOS Quality of Service Solutions Configuration Guide
Additional QoS commands
Standards
MIBs
MIB MIBs LinkNone
To locate and download MIBs for selected platforms, Cisco IOS releases, and feature sets, use Cisco MIB Locator found at the following URL:
RFCs
Technical Assistance
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
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iphc-profile
•
non-tcp
•
recoverable-loss
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rtp
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show frame-relay ip rtp header-compression
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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 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.
© 2007 Cisco Systems, Inc. All rights reserved.
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