# Classifier Groups and Policy Rules Overview

Classifier groups contain the policy rules that make up a policy list. A policy rule is an association between a policy action and an optional CLACL. The CLACL defines the packet flow on which the policy action is taken.

A policy list might contain multiple classifier groups—you can specify the precedence in which classifier groups are evaluated. Classifier groups are evaluated starting with the lowest precedence value. Classifier groups with equal precedence are evaluated in the order of creation.

| Note: For IP policies, the forward command supports the order keyword, which enables you to order multiple forward rules within a single classifier group. (See Using Policy Rules to Provide Routing Solutions.)

From Policy Configuration mode, you can assign a precedence value to a CLACL by using the precedence keyword when you create a classifier group. The default precedence value is 100. For example:

host1(config-policy-list)#classifier-group ipCLACL25 precedence 21 host1(config-policy-list-classifier-group)#

The classifier-group command puts you in Classifier Group Configuration mode. In this mode you configure the policy rules that make up the policy list. For example:

host1(config-policy-list-classifier-group)#forward next-hop 172.18.20.54

To stop and start a policy rule without losing statistics, you can suspend the rule. Suspending a rule maintains the policy rule with its current statistics, but the rule no longer affects packets in the forwarding path.

From Classifier Group Configuration mode, you can suspend a rule by using the suspend version of that policy rule command. The no suspend version reactivates a suspended rule. For example:

host1(config-policy-list-classifier-group)#suspend forward next-hop 172.18.20.54 host1(config-policy-list-classifier-group)#no suspend forward next-hop 172.18.20.54

You can add, remove, or suspend policy rules while the policy is attached to one or more interfaces. The modified policy takes effect once you exit Policy Configuration mode.