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312 Chapter 10: Managing Network Performance with Queuing and Compression
Verifying Custom Queuing
Verifying your queuing configuration is relatively simple. The most useful command is show
queueing. It shows the detail of the custom lists configured on the router and the appropriate
details of each list. Example 10-12 shows the command output.
Example 10-12 notes the default queue and then line-by-line details about the remainder of the
queue configuration. Note that the changes that were made to the queue sizes are noted along
with the queue that was altered.
Compression Overview
Various types of compression algorithms are in use in the world today. Many are well conceived
and utilized. Others, well, let's just say they're the opposite.
For compression, a scope needs to be set ahead of time. There are compression methods for
data, links, hard drives, and so on. Our discussion in this chapter focuses on compression across
WAN links.
Whether data is already compressed when WAN links begin to process it affects the router's
capability to further compress that data. If data is already compressed, recompressing can
actually make the data larger. The discussion in this chapter focuses on what happens at the
WAN interface, regardless of the type of data being transported.
Compression is but one technique for squeezing every possible bit of bandwidth from an
existing internetwork deployment. Compression, like queuing, is meant to provide critical time
to plan and deploy network upgrades and to reduce overall utilization of a WAN link. However,
nothing is free. The execution of the compression algorithm adds a significant amount of cycles
to the CPU. Unfortunately, the additional load on the CPU might not be something it can
handle.
Example 10-12
show queueing custom Command Output
RouterA#show queueing custom
Current custom queue configuration:
List Queue Args
1 5 default
1 6 interface Ethernet 0
1 1 protocol ip tcp port ftp
1 1 protocol ip tcp port ftp-data
1 2 protocol ip
1 3 protocol ipx
1 4 protocol appletalk
1 1 queue-limit 60
1 1 byte-count 4500