Cisco Systems 3825 manual Ip tcp header-compression, Keyword, all TCP packets are compressed

Appendix A Cisco 3825 Mobile Wireless Edge Router RAN-O Command Reference

ip tcp header-compression

ip tcp header-compression

To enable TCP header compression, use the ip tcp header-compressioncommand in interface configuration mode. To disable compression, use the no form of this command.

ip tcp header-compression [passive] [iphc-format][ietf-format]

no ip tcp header-compression [passive] [iphc-format][ietf-format]

Syntax Description

Defaults

passive	(Optional) Compresses outgoing TCP packets only if incoming TCP packets
	on the same interface are compressed. If you do not specify the passive
	keyword, all TCP packets are compressed.
iphc-format	(Optional) Indicates that the IP Header Compression (IPHC) format of
	header compression will be used.
ietf-format	(Optional) Indicates that the Internet Engineering Task Force (IETF) format
	of the header compression will be used.

Disabled

For PPP interfaces, default format for header compression is the IPHC format.

For High-Level Data Link Control (HDLC) and Frame Relay interfaces, the default format is as described in RFC 1144, Compressing TCP/IP Headers for Low-Speed Serial Links.

Command Modes

Command History

Interface configuration

Release	Modification
10.0	This command was introduced.
12.0	This command was incorporated. This command was modified to include the
	iphc-format keyword.
12.3(4)T	This command was incorporated. This command was modified to include the
	ietf-format keyword.
12.4(2)MR	This command was incorporated.

Usage Guidelines You can compress the headers of your TCP/IP packets in order to reduce the size of your packets. TCP header compression is supported on serial lines using Frame Relay, HDLC, or PPP encapsulation. You must enable compression on both ends of a serial connection. Compressing the TCP header can speed up Telnet connections dramatically.

In general, TCP header compression is advantageous when your traffic consists of many small packets, not for traffic that consists of large packets. Transaction processing (usually using terminals) tends to use small packets and file transfers use large packets. This feature only compresses the TCP header, so it has no effect on User Datagram Protocol (UDP) packets or other headers.

	Cisco 3825 Mobile Wireless Edge Router Software Configuration Guide
A-44	OL-15667-03