Defining Filters
You create filters to identify packet flows as members of a particular class. Each filter contains selectors, which define the criteria for evaluating a packet flow. The IPQoS-enabled system uses the criteria in the selectors to extract packets from a traffic flow. The IPQoS system then associates the packets with a class. For an introduction to filters, see IPQoS Filters on page 16.
Use only as many selectors as you need to extract packets for a class. The more selectors that you define, the greater the impact on IPQoS performance.
The following table lists the most commonly used selectors. The first five selectors represent the IPQoS 5-tuple, which the IPQoS system uses to identify packets as members of a flow. For a complete list of selectors, see Figure 4, Table 4, Filter Selectors for the IPQoS Classifier.
Table 2 Common IPQoS Selectors
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