Configuring the Route Distinguisher

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 Border Gateway Protocol (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:

• [edit routing-instances routing-instance-name]
• [edit logical-routers logical-router-name routing-instances routing-instance-name]

The route distinguisher is a 6-byte value that you can specify in one of the following formats:

• as-number:number, where as-number is an autonomous system (AS) number (a 2-byte value) and number is any 4-byte value. The AS number can be in the range 1 through 65,535. We recommend that you use an Internet Assigned Numbers Authority (IANA)-assigned, nonprivate AS number, preferably the Internet service provider's (ISP's) own or the customer's own AS number.
• ip-address:number, where ip-address is an IP address (a 4-byte value) and number is any 2-byte value. The IP address can be any globally unique unicast address. We recommend that you use the address that you configure in the router-id statement, which is a nonprivate address in your assigned prefix range.

If you configure the route-distinguisher-id statement at the [edit routing-options] hierarchy level, a route distinguisher is automatically assigned to the routing instance. If you configure the route-distinguisher statement in addition to the route-distinguisher-id statement, the value configured for route-distinguisher supersedes the value generated from route-distinguisher-id.

To assign a route distinguisher automatically, include the route-distinguisher-id statement:

route-distinguisher-id ip-address;

You can include the route-distinguisher-id statement at the following hierarchy levels:

• [edit routing-options]
• [edit logical-routers logical-router-name routing-options]

A type 1 route distinguisher is automatically assigned to the routing instance using the format ip-address:number. The IP address is specified by the route-distinguisher-id statement and the number is unique for the routing instance.