10.3
Optimizing Traffic Flow with Data Compression
10.3.7 Configuring data compression
Use the compress [predictor|stac|mppc] command to configure point-to-point software compression for a LAPB, PPP, or HDLC link. Data-compression schemes used in internetworking devices are referred to as lossless compression algorithms. These schemes reproduce the original bit streams exactly, with no degradation or loss, a feature that is required by routers and other devices to transport data across the network:

Router(config-if)#compress [predictor | stac | mppc]

Use the frame-relay payload-compress command to enable STAC compression on a specified Frame Relay point-to-point interface or subinterface:

Router(config-if)#frame-relay payload-compress

Use the x25 map compressdtcp command to map compressed TCP headers to an X.121 address for a given link.

Use the ip tcp header-compression command to enable TCP header compression. The passive keyword compresses outgoing TCP packets, only if incoming TCP packets on the same interface are compressed. If passive is not specified, the router will compress all traffic:

Router(config-if)#ip tcp header-compression [passive]

Remember: Never recompress data. Compressed data does not compress; it actually expands.

Lab Activity
  Our company has analyzed the bandwidth usage on our EastCoast to WestCoast ISDN connection. It has been found that we are using the ISDN line to the maximum. There is not enough money in the budget to upgrade the line to a PRI link, or to allow the ISDN line to be on all the time. It is our responsibility to find a way to move more information across the link in less time. Our solution: Compression.
Lab Activity
  Our company has analyzed the bandwidth usage on our Houston to Orlando Frame Relay connection. It has been found that we are using the Frame Relay line to the maximum. There is not enough money in the budget to upgrade the line. It is our responsibility to find a way to move more information across the link. Our solution: Compression.