Riverstone Networks WICT1-12 - Manual (Page 608)

30-4 Riverstone Networks RS Switch Router User Guide Release 8.0
Configuring WAN Interfaces WAN Configuration
30.2.3 Forcing Bridged Encapsulation
WAN for the RS has the ability to force bridged packet encapsulation. This feature has been provided to facilitate
seamless compatibility with Cisco routers, which expect bridged encapsulation in certain operating modes.
The following command line displays an example for Frame Relay:
The following command line displays an example for PPP:
30.2.4 Packet Compression
Packet compression can increase throughput and shorten the times needed for data transmission. You can enable packet
compression for Frame Relay VCs and for PPP ports, however, both ends of a link must be configured to use packet
compression.
Enabling compression on WAN serial links should be decided on a case by case basis. Important factors to consider
include:
• Average packet size
• Nature of the data
• Link integrity
• Latency requirements
Each of these factors is discussed in more detail in the following sections and should be taken into consideration before
enabling compression. Since the factors are dependent on the environment, you should first try running with
compression histories enabled. If compression statistics do not show a very good long-term compression ratio, then
select the “no history” option. If the compression statistics do not improve or show a ration of less than 1, then
compression should be disabled altogether.
Average Packet Size
In most cases, the larger the packet size, the better the potential compression ratio. This is due to the overhead involved
with compression, as well as the compression algorithm. For example, a link which always deals with minimum size
packets may not perform as well as a link whose average packet size is much larger.
Nature of the Data
In general, data that is already compressed cannot be compressed any further. In fact, packets that are already
compressed will grow even larger. For example, if you have a link devoted to streaming MPEG videos, you should not
enable compression as the MPEG video data is already compressed.
rs(config)# frame-relay set fr-encaps-bgd ports hs.5.2.19
rs(config)# ppp set ppp-encaps-bgd ports hs.5.2