Configure Interfaces for VPN Routing

On each PE router, you must configure an interface over which the VPN traffic travels between the PE and CE routers. To do this, include the interface statement at the [edit routing-instances routing-instance-name] hierarchy level:

[edit routing-instances routing-instance-name]

interface interface-name; 

Specify both the physical and logical portions of the interface name, in the following format:

physical.logical

For example, in so-1/2/1.0, so-1/2/1 is the physical portion of the interface name and 0 is the logical portion. If you do not specify the logical portion of the interface name, 0 is used.

A logical interface can be associated with only one routing instance.

When you configure the same interface at the [edit interfaces] hierarchy level, you must also configure family inet and family mpls when configuring the logical interface:

[edit interfaces]

interface-name {

    unit logical-unit-number {

        family inet;

        family mpls;

    }

}

 If you enable a routing protocol on all instances by specifying interfaces all when configuring the master instance of the protocol at the [edit protocols] hierarchy level, and if you configure a specific interface for VPN routing at the [edit routing-instances routing-instance-name] hierarchy level, the latter interface statement takes precedence and the interface is used exclusively for the VPN.
 If you explicitly configure the same interface name at both the [edit protocols] and [edit routing-instances routing-instance-name] hierarchy levels, when you try to commit the configuration, it will fail.