Riverstone Networks WICT1-12 - Manual (Page 609)

Riverstone Networks RS Switch Router User Guide Release 8.0 30-5
WAN Configuration Configuring WAN Interfaces
Link Integrity
Links with high packet loss or links that are extremely over-subscribed may not perform as well with compression
enabled. If this is the situation on your network, you should not enable compression histories. This applies only to PPP
compressions. In Frame Relay compression, histories are always used.
Compression histories take advantage of data redundancy between packets. In an environment with high packet loss
or over-subscribed links, there are many gaps in the packet stream resulting in very poor use of the compression
mechanism. Compression histories work best with highly-correlated packet streams. Thus, a link with fewer flows will
generally perform better than a link with many flows when compression histories are utilized.
The “no history” (max-histories = 0) option causes packets to be compressed on a packet-by-packet basis, thus packet
loss is not a problem. Also, the number of flows is not an issue with this option as there is no history of previous
packets.
Latency Requirements
The use of compression may affect a packet’s latency. Since the compressed packet is smaller, less time is needed to
transmit it. On the other hand, each packet must undergo a compression/decompression process. Since the compression
ratio will vary, the amount of latency will also vary.
Example Configurations
The following command line displays an example for Frame Relay:
The following command line displays an example for PPP:
30.2.5 Packet Encryption
Packet encryption allows data to travel through unsecured networks. You can enable packet encryption for PPP ports,
however, both ends of a link must be configured to use packet encryption.
The following command line displays an example:
30.2.6 WAN Quality of Service
Increasing concentrations of audio, video, and data traffic are now presenting the networking industry with the
significant challenge of employing the most effective use of WAN Quality-of-Service (QoS) as possible to ensure
reliable end-to-end communication. For example, critical and time-sensitive traffic such as audio should have higher
rs(config)# frame-relay set payload-compress ports se.3.1.300
rs(config)# ppp set payload-compress port se.4.2
rs(config)# ppp set payload-encrypt transmit-key 0x123456789abcdef receive-key
0xfedcba987654321 port se.4.2, mp.1