Alcatel Carrier Internetworking Solutions Switch/Router ユーザーズマニュアル

Page 28-12

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.

Compression is not supported on the Omni 
Switch/Router 

WSX-S-2W

 modules.