Policy Rule Precedence - Juniper POLICY MANAGEMENT - CONFIGURATION GUIDE V11.1.X Configuration Manual

JUNOSe 11.1.x Policy Management Configuration Guide
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" on page 35.)
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:
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:
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:
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 Precedence

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.
The precedence of rules is important if you want a specific rule to be applied. For
example, if an IP policy list has both a rate-limit-profile rule (which specifies a color)
and a color rule in the same classifier-group, the color specified by the color rule is
always used rather than the color implied in the rate-limit-profile rule (the color rule
has a higher precedence).
Table 4 on page 33 lists the policy rule commands that you can use for each type of
policy list. The table lists the rules in their order of precedence.
32
Policy Rule Precedence
host1(config-policy-list)#classifier-group ipCLACL25 precedence 21
host1(config-policy-list-classifier-group)#
host1(config-policy-list-classifier-group)#forward next-hop 172.18.20.54
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