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

Page 29-5

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 

DRAM

 that can 

store up to 100 virtual circuits (on a 4-port 

WSX

) without performance degradation. An 8-port 

WSX

 can store up to 200 virtual circuits without performance degradation. Support for more 

than 100 compressed VCs (or 200 VCs on an 8-port 

WSX

) is possible through swapping within 

memory, but compression performance may decrease at these levels.

The 

WSX

 will only compress data if you enable Compression Negotiation through software 

and the Bridge/Router on the other end of the Frame Relay virtual circuit supports standard 
FRF.9 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, then this Bridge/Router will not recognize 
the data and will automatically drop the unrecognizable frames.

If you enable Compression Negotiation, the 

WSX

 will query the Frame Relay device on the 

other end of the circuit (according to 

FRF.9

 specifications) to see if it supports compression. If 

it does, then the 

WSX

 compresses all data except 

DLCMI

 (management) data. If it doesn’t, then 

data on that virtual circuit is sent uncompressed. See Setting Configuration Parameters on 
page 29-22 for information on enabling compression.

Compression is not supported on the 2 universal serial 
port Omni Switch/Router 

WSX

 and Omni Switch/Router 

WSX

 modules.