Creating Classifier Groups And Policy Rules; Policy Rule Support - Juniper E320 Configuration Manual

Creating Classifier Groups and Policy Rules

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:
enables you to order multiple forward rules within a single classifier group. (See
Rules That 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.

Policy Rule Support

Because of the flexibility in creating policy lists and classifier groups, you can
configure a classifier group that has multiple policy rules.
If a classifier group has multiple rules, the router uses the rules according to their
precedence—not in the order in which you created the rules. The first rule listed
(the forward rule) for a policy list type has the highest precedence and the last rule
has the lowest. The precedence is based on the order in which the router performs
rules. Rules are performed in order from lower to higher precedence. In the event of
a conflict, a higher precedence rule overrides the lower precedent rule.
For IP policies, the forward command supports the order keyword, which
on page 33.)
Creating Classifier Groups and Policy Rules
Chapter 2: Creating Policies
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