system 123. If they were advertised, they are passed; otherwise, they are implicitly dropped at the end of all
policy processing.
The done statement indicates that the action to take is to stop executing the policy and accept the route. When
encountering a done statement, the route is passed and no further policy statements are executed. All
modifications made to the route prior to the done statement are still valid.
Action
An action is a sequence of primitive operations that modify a route. Most actions, but not all, are distinguished
by the set keyword. In a route policy, actions can be grouped together. For example, the following is a route
policy comprising three actions:
route-policy actions
set med 217
set community (12:34) additive
delete community in (12:56)
end-policy
If
In its simplest form, an if statement uses a conditional expression to decide which actions or dispositions
should be taken for the given route. For example:
if as-path in as-path-set-1 then
drop
endif
The example indicates that any routes whose AS path is in the set as-path-set-1 are dropped. The contents of
the then clause may be an arbitrary sequence of policy statements.
The following example contains two action statements:
if origin is igp then
set med 42
prepend as-path 73.5 5
endif
The CLI provides support for the exit command as an alternative to the endif command.
The if statement also permits an else clause, which is executed if the if condition is false:
if med eq 8 then
set community (12:34) additive
else
set community (12:56) additive
endif
The policy language also provides syntax, using the elseif keyword, to string together a sequence of tests:
if med eq 150 then
set local-preference 10
elseif med eq 200 then
set local-preference 60
elseif med eq 250 then
set local-preference 110
Cisco ASR 9000 Series Aggregation Services Router Routing Configuration Guide, Release 5.3.x
565
Implementing Routing Policy
Policy Statements
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