Table Of Contents
Frame Relay Header Compression
Compatibility Enhancementsframe-relay ip rtp compression-connections
frame-relay ip tcp compression-connections
frame-relay map ip rtp header-compression
frame-relay map ip tcp header-compression
Frame Relay Header Compression
Compatibility Enhancements
This document describes the new and modified commands used to specify the maximum number of compressed connections when using IP header compression over Frame Relay links.
Overview
Before Cisco IOS Release 12.1(2)T, the maximum number of IP header compression connections was fixed at 256 connections for Cisco IOS Release 12.0(7)T and later releases and at 16 or 32 connections for earlier releases. The inability to specify the number of connections sometimes resulted in compatibility conflicts.
With Cisco IOS Release 12.1(2)T, the following commands were introduced or modified to enable a user to specify the maximum number of compressed connections when using Real-Time Transport Protocol (RTP) or TCP header compression over a Frame Relay link:
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frame-relay ip rtp compression-connections
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Command Reference
This section documents new or modified commands. All other commands used with this feature are documented in the Cisco IOS Release 12.1 command reference publications.
frame-relay ip rtp compression-connections
To specify the maximum number of Real-Time Transport Protocol (RTP) header compression connections that can exist on a Frame Relay interface, use the frame-relay ip rtp compression-connections interface configuration command. To restore the default, use the no form of this command.
frame-relay ip rtp compression-connections number
no frame-relay ip rtp compression-connections
Syntax Description
Defaults
No default behavior or values.
Command Modes
Interface configuration
Command History
Usage Guidelines
Before you can configure the maximum number of connections, RTP header compression must be configured on the interface using the frame-relay ip rtp header-compression command.
The number of RTP header compression connections must be set to the same value at each end of the connection.
Examples
The following example shows the configuration of a maximum of 150 RTP header compression connections on serial interface 0:
interface serial 0encapsulation frame-relayframe-relay ip rtp header-compressionframe-relay ip rtp compression-connections 150Related Commands
frame-relay ip tcp compression-connections
To specify the maximum number of TCP header compression connections that can exist on a Frame Relay interface, use the frame-relay ip tcp compression-connections interface configuration command. To restore the default, use the no form of this command.
frame-relay ip tcp compression-connections number
no frame-relay ip tcp compression-connections
Syntax Description
Defaults
No default behavior or values.
Command Modes
Interface configuration
Command History
Usage Guidelines
Before you can configure the maximum number of connections, TCP header compression must be configured on the interface using the frame-relay ip tcp header-compression command.
The number of TCP header compression connections must be set to the same value at each end of the connection.
Examples
The following example shows the configuration of a maximum of 150 TCP header compression connections on serial interface 0:
interface serial 0encapsulation frame-relayframe-relay ip tcp header-compressionframe-relay ip tcp compression-connections 150Related Commands
frame-relay map ip compress
To enable both Real-Time Transport Protocol (RTP) and TCP header compression on a link, use the frame-relay map ip compress interface configuration command.
frame-relay map ip ip-address dlci [broadcast] compress [active | passive]
[connections number]Syntax Description
Defaults
Disabled.
The default maximum number of header compression connections is 256.
Command Modes
Interface configuration
Command History
11.3
This command was introduced.
12.1(2)T
This command was modified to enable the configuration of the maximum number of header compression connections.
Examples
The following example enables both RTP and TCP header compression on serial interface 1 and sets the maximum number of RTP and TCP header connections at 16:
interface serial 1encapsulation frame-relayip address 10.108.175.110 255.255.255.0frame-relay map ip 10.108.175.220 180 compress connections 16Related Commands
frame-relay map ip nocompress
To disable both Real-Time Transport Protocol (RTP) and TCP header compression on a link, use the frame-relay map ip nocompress interface configuration command.
frame-relay map ip ip-address dlci [broadcast] nocompress
Syntax Description
ip-address
IP address of the destination or next hop.
dlci
Data-link connection identifier (DLCI) number.
broadcast
(Optional) Forwards broadcasts to the specified IP address.
Defaults
No default behaviors or values.
Command Modes
Interface configuration
Command History
Examples
The following example disables RTP and TCP header compression on DLCI 180:
interface serial 1encapsulation frame-relayframe-relay map ip 10.108.175.220 180 nocompressRelated Commands
frame-relay map ip rtp header-compression
To enable Real-Time Transport Protocol (RTP) header compression per data-link connection identifier (DLCI), use the frame-relay map ip rtp header-compression interface configuration command.
frame-relay map ip ip-address dlci [broadcast] rtp header-compression [active | passive] [connections number]
Syntax Description
Defaults
Disabled.
If the command is configured, active is the default keyword.
The default maximum number of header compression connections is 256.
Command Modes
Interface configuration
Command History
11.3
This command was introduced.
12.1(2)T
This command was modified to enable the configuration of the maximum number of header compression connections.
Usage Guidelines
When this command is configured, the specified maps inherit RTP header compression. You can have multiple Frame Relay maps, with and without RTP header compression. If you do not specify the number of RTP header compression connections, the map will inherit the current value from the interface.
Examples
The following example enables RTP header compression on serial interface 1 and sets the maximum number of RTP header compression connections at 64:
interface serial 1encapsulation frame-relayip address 10.108.175.110 255.255.255.0frame-relay map ip 10.108.175.220 180 rtp header-compression connections 64Related Commands
frame-relay map ip tcp header-compression
To assign header compression characteristics to an IP map that differ from the compression characteristics of the interface with which the IP map is associated, use the frame-relay map ip tcp header-compression interface configuration command.
frame-relay map ip ip-address dlci [broadcast] tcp header-compression [active | passive] [connections number]
Syntax Description
Defaults
The default maximum number of header compression connections is 256.
Command Modes
Interface configuration
Command History
10.0
This command was introduced.
12.1(2)T
This command was modified to enable the configuration of the maximum number of header compression connections.
Usage Guidelines
If you do not specify the number of TCP header compression connections, the map will inherit the current value from the interface.
IP maps inherit the compression characteristics of the associated interface unless this command is used to provide different characteristics. This command can also reconfigure an IP map that existed before TCP header compression was configured on the associated interface.
When IP maps at both ends of a connection inherit passive compression, the connection will never transfer compressed traffic because neither side will generate a packet with a compressed header.
If you change the encapsulation characteristics of the interface to Internet Engineering Task Force (IETF) encapsulation, you lose the TCP header compression configuration of the associated IP map.
The frame-relay map ip ip-address dlci tcp header-compression active command can also be entered as frame-relay map ip ip-address dlci active tcp header-compression.
We recommend that you shut down the interface before changing encapsulation types. Although this is not required, shutting down the interface ensures that the interface is reset for the new encapsulation.
Examples
The following example illustrates a command sequence for configuring an IP map associated with serial interface 1 to enable active TCP/IP header compression:
interface serial 1encapsulation frame-relayip address 10.108.177.170 255.255.255.0frame-relay map ip 10.108.177.180 190 tcp header-compression activeRelated Commands
Guest