Using the Layer 2 Interworking Interface to Interconnect a Layer 2 VPN to a Layer 2 VPN

Instead of using a physical Tunnel PIC for looping the packet received from the Layer 2 VPN to another Layer 2 VPN, the Layer 2 Interworking interface uses Junos OS to stitch together both Layer 2 VPN routes.

To configure the interworking interface, include the iw0 statement. The iw0 statement is configured at the [edit interfaces] hierarchy level.

[edit interfaces]
iw0 {
    unit 0 {
        peer 1;
    }
    unit 1 {
        peer 0;
    }
}

set interfaces iw0 unit 0 peer-unit 1
set interfaces iw0 unit 1 peer-unit 0

The configuration of an interworking (iw) interface is similar to the configuration of a logical tunnel (lt) interface. In this example, the logical interfaces must be associated with the endpoints of both Layer 2 VPN connections terminating on this router. To make the association, include the interfaces statement and specify iw0 as the interface name. Include the statement at the [edit routing-instances routing-instances-name protocols l2vpn site site-name] hierarchy level for each routing instance. The routing-instances statement is configured at the [edit routing-instances] hierarchy level.

[edit routing-instances]
L2VPN-PE1 {
    instance-type l2vpn;
    interface iw0.0;
    route-distinguisher 65000:3;
    vrf-target target:65000:2;
    protocols {
        l2vpn {
            encapsulation-type ethernet;
            site CE3 {
                site-identifier 3;
                interface iw0.0 {
                    remote-site-id 1;
                }
            }
        }
    }
}
L2VPN-PE5 {
    instance-type l2vpn;
    interface iw0.1;
    route-distinguisher 65000:33;
    vrf-target target:65000:2;
    protocols {
        l2vpn {
            encapsulation-type ethernet;
            site CE3 {
                site-identifier 3;
                interface iw0.1 {
                    remote-site-id 5;
                }
            }
        }
    }
}

In addition to the iw0 interface configuration, Layer 2 interworking l2iw protocols need to be configured. Without the l2iw configuration, the l2iw routes will not be formed, regardless of whether any iw interfaces are present. Only standard trace options can be configured within the l2iw protocol. The minimum configuration necessary for the feature to work is shown below:

[edit]
protocols {
    l2iw;
}