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. The configuration described in this section is applicable to all types of VPNs. However, Layer 3 VPNs and carrier-of-carriers VPNs require some additional configuration described in the following sections:

• Configure Interfaces for Layer 3 VPNs
• Configure Interfaces for Carrier-of-Carriers VPNs

To configure interfaces for VPN routing, include the interface statement:

[edit routing-instances routing-instance-name]

interface interface-name; 

You can configure this statement at the following hierarchy levels:

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

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

physical.logical

For example, in at-1/2/1.2, at-1/2/1 is the physical portion of the interface name and 2 is the logical portion. If you do not specify the logical portion of the interface name, 0 is set by default.

A logical interface can be associated with only one routing instance. 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 or at the [edit logical-routers logical-router-name 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 the [edit protocols] and at either the [edit routing-instances routing-instance-name] or [edit logical-routers logical-router-name routing-instances routing-instance-name] hierarchy levels, when you try to commit the configuration, it will fail.