Alcatel Carrier Internetworking Solutions Switch/Router Data Compression

Data Compression
Page 28-12
Data Compression
Data compression allows you to get more data through the Frame Relay pipeline, further
enhancing cost benefits. A typical data compression ratio on the WSX board at the hardware
level is 4:1. In addition, the compression processor (STAC 9705) has its own memory (DRAM)
that can store up to 100 compression histories (on a 4-port WSX) without degrading
performance. An 8-port WSX can store up to 200 compression histories without performance
degradation.
The WSX will only compress data if you enable compression through software and the
bridge/router on the other end of the connection supports standard Frame Relay (FRF.9) or
PPP (STAC-LZS) compression. (An Omni Switch/Router-to-Omni Switch/Router connection
would support compression.) Negotiation is necessary because if compressed data is sent to a
bridge/router that does not support compression, this bridge/router will not recognize the
data and will automatically drop the unrecognizable frames.
If you enable compression, the WSX will query the Frame Relay or PPP device on the other
end of the circuit to determine whether it supports compression. If it does, the WSX will
compress all data except frame DLCMI (management) data and PPP control messages. If it
does not support compression, data on that connection will be sent uncompressed. Refer to
either Chapter 29, “Managing Frame Relay,” or Chapter 30, “Point-To-Point Protocol,” for
information on enabling compression.
Note
Compression is not supported on the Omni
Switch/Router WSX-S-2W modules.