Configuring a GRE Tunnel Interface Between a PE and CE Router
This example shows how to configure a GRE tunnel interface between a PE router and a CE router. You can use this configuration to tunnel VPN traffic across a non-MPLS core network. The network topology used in this example is shown in Figure 1.
Figure 1: GRE Tunnel Between the CE Router and the PE Router

For this example, complete the procedures described in the following sections:
Configuring the Routing Instance Without the Encapsulating Interface
You can configure the routing instance either with or without the encapsulating interface. The following sections explain how to configure the routing instance without it:
- Configuring the Routing Instance on Router PE1
- Configuring the GRE Tunnel Interface on Router PE1
- Configuring the Encapsulation Interface on Router PE1
Configuring the Routing Instance on Router PE1
Configure the routing instance on Router PE1:
Configuring the GRE Tunnel Interface on Router PE1
Configure the GRE tunnel interface on Router PE1:
In this example, interface t3-0/1/3 acts as the encapsulating interface for the GRE tunnel.
Configuring the Encapsulation Interface on Router PE1
Configure the encapsulation interface on Router PE1:
Configuring the Routing Instance with the Encapsulating Interface
If the tunnel-encapsulating interface, t3-0/1/3, is also configured under the routing instance, then you need to specify the name of that routing instance under the interface definition. The system uses this routing instance to search for the tunnel destination address.
To configure the routing instance with the encapsulating interface, you perform the steps in the following sections:
- Configuring the Routing Instance on Router PE1
- Configuring the GRE Tunnel Interface on Router PE1
- Configuring the Encapsulation Interface on Router PE1
Configuring the Routing Instance on Router PE1
If you configure the tunnel-encapsulating interface under the routing instance, then configure the routing instance on Router PE1:
Configuring the GRE Tunnel Interface on Router PE1
Configure the GRE tunnel interface on Router PE1:
Configuring the Encapsulation Interface on Router PE1
Configure the encapsulation interface on Router PE1:
Configuring the GRE Tunnel Interface on Router CE1
Configure the GRE tunnel interface on Router CE1: