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Chapter 11. Managing Network Performance with Queuing and Compression

This chapter covers the following topics:

• Considerations for Traffic Prioritization

• Queuing Operations

• Configuring and Verifying Queuing

• Compression

Many networks today need to support a diverse mixture of applications and protocols. These applications can range from delay-sensitive traffic such as desktop videoconferencing to file transfers that use FTP. Because these different types of traffic share the same network infrastructure, they can negatively affect each other.

Depending on the applications and the overall available bandwidth, congestion can occur. Often this congestion occurs at routers where there is a disparity in speed between two interfaces. For instance, packets might arrive on a Fast Ethernet interface that need to go out on a low-speed WAN link. These packets might arrive faster than the router can send them. At this point, the need for congestion management arises.

Congestion management consists of the following:

• Prioritizing traffic so that applications such as videoconferencing are assigned a higher priority than FTP traffic

• Creating different queues for different priorities of traffic

• Assigning traffic to its appropriate queues

• The order in which these queues are serviced (the order in which traffic is sent)

Congestion management can ensure that even if congestion occurs, traffic can be sent in a prioritized manner so that network performance is not affected and the impact on users is minimized. Queuing mechanisms on routers are an important way of reducing congestion.

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