Each routing instance that you configure on a PE router must have a unique route distinguisher associated with it. VPN routing instances need a route distinguisher to help the BGP to distinguish between potentially identical network layer reachability information (NLRI) messages received from different VPNs.
We recommend that you use a unique route distinguisher for each routing instance that you configure. Although you can use the same route distinguisher on all PE routers in the same VPN, if you use a unique route distinguisher, you can determine the PE router from which a route originated.
To configure a route distinguisher on a PE router, include the route-distinguisher statement:
-
route-distinguisher (as-number:number | ip-address:number);
You can include the route-distinguisher statement at the following hierarchy levels:
The route distinguisher is a 6-byte value that you can specify in one of the following formats: