Specify Policy with Aggregate Routes

You can associate a routing policy when configuring an aggregate route's destination prefix in the routes part of the aggregate statement. Doing so provides the equivalent of an import routing policy filter for the destination prefix. That is, each potential contributor to an aggregate route, along with any aggregate options, is passed through the policy filter. The policy then can accept or reject the route as a contributor to the aggregate route and, if the contributor is accepted, the policy can modify the default preferences. The contributor with the numerically smallest prefix becomes the most preferred, or primary, contributor. A rejected contributor still can contribute to less specific aggregate route. If you do not specify a policy filter, all candidate routes contribute to an aggregate route.

To associate a routing policy with an aggregate route, include the policy statement when configuring the route:

[edit routing-options aggregate (defaults | route)] 

policy policy-name; 

For a list of hierarchy levels at which you can configure this statement, see the statement summary section for this statement.