All routing protocols store the routes that they learn in the routing table. The routing table uses this collected route information to determine the active routes to destinations. The routing table then installs the active routes into its forwarding table and exports them into the routing protocols. It is these exported routes that the protocols advertise.
For each protocol, you control which routes the protocol stores in the routing table and which routes the routing table exports into the protocol from the routing table by defining a routing policy for that protocol. For information about defining routing policy, see the JUNOS Policy Framework Configuration Guide.
To apply routing policies that affect how the routing protocol process (rpd) exports routes into IS-IS, include the export statement:
- export [ policy-names ];
For a list of hierarchy levels at which you can include this statement, see the statement summary section for this statement.
Note: For IS-IS, you cannot apply routing policies that affect how routes are imported into the routing table; doing so with a link-state protocol can easily lead to an inconsistent topology database.