Wednesday, November 12, 2008

Frame Relay - TCP and RTP header compression

TCP or RTP compression can be used to increase efficiency of bandwidth utilisation on slow serial connections. It can be enabled on a per interface basis or simply on a per DLCI basis. Likewise if enabled on a physical interface it can then also be disabled on a per DLCI basis.

Configuration for RTP and TCP compression follows the same syntax. In this post i detail the steps necessary to enable RTP compression first on an interface and second just on a single DLCI.

First to enable on an interface.

config-if#ip rtp header-compression


config-if#ip rtp header-compression passive

In the first case header compression is applied to all packets, whereas in the later it is only applied to those packets that arrive with header compression already enabled.

Second to apply on a per DLCI basis

config-if#frame-relay map ip 403 rtp header-compression active connections 15

Documentation can be found on the DOC CD under the WAN Configuration section at

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