CPM - Collect keyword

When configuring the Cisco Performance Monitor (CPM) feature, the collect keyword has a very specific function.

The collect command is used to specify additional fields to be recorded for each network traffic flow. These fields are called nonkey fields.

Key fields are used to define and identify a unique flow (like source/destination IP addresses, ports, protocol types). Nonkey fields provide supplementary information about each flow. They enrich the flow record but do not define the flow itself. So additional information about the specific flow is collected, but only as nonkey fields.

For example, the collect ipv4 destination prefix command is used to gather statistics about destination IP address prefixes in the packets being monitored, as nonkey fields. The complete command syntax is:

collect ipv4 destination {address | {mask | prefix} [minimum-mask mask ]}

Take a look at the Cisco command reference documentation linked below for more information on the specific command. The same document includes all of the collect commands as well.

Contrast the use of the collect keyword with the match keyword.