System Administration Guide: IP Services

Using Classes of Service to Prioritize Traffic

To implement quality of service, you analyze network traffic to determine any broad groupings into which the traffic can be divided. Then, you organize the various groupings into classes of service with individual characteristics and individual priorities. These classes form the basic categories on which you base the QoS policy for your organization. The classes of service represent the traffic groups that you want to control.

For example, a provider might offer platinum, gold, silver, and bronze levels of service, available at a sliding price structure. A platinum SLA might guarantee top priority to incoming traffic that is destined for a web site that the ISP hosts for the customer. Thus, incoming traffic to the customer's web site could be one traffic class.

For an enterprise, you could create classes of service that are based on department requirements. Or, you could create classes that are based on the preponderance of a particular application in the network traffic. Here are a few examples of traffic classes for an enterprise: