# Example: Configuring Many Shim Interfaces with the Same Peer, VC Type, and VC ID

In this example, the following commands create a single layer 2 circuit to the remote peer 10.9.1.3. Load balancing is established on two shim interfaces, fastEthernet 2/0.1 and fastEthernet 3/0.1. The VC type is determined by the layer 2 interface type.

host1(config)#interface fast 2/0.1 host1(config-subif)#vlan id 1 host1(config-subif)#mpls-relay 10.9.1.3 200001 host1(config-subif)#exit host1(config)#interface fast 3/0.1 host1(config-subif)#vlan id 1 host1(config-subif)#mpls-relay 10.9.1.3 200001

In this example, the router advertises a single label, 53, to the remote peer, 10.9.1.3, and receives a single label, 55, from the peer, resulting in the following forwarding table:

    host1:# show mpls forwarding brief
    Platform label space
    In Label  Owner                                 Action
    -------- -------- -------------------------------------------------------
    53       ldp      l2transport to FastEthernet3/0.1
                      l2transport to FastEthernet2/0.1
    L2transport
         Interface        Owner                      Action
    -------------------- -------- -------------------------------------------------
    FastEthernet2/0.1    ldp      swap to 55, push 42 on ATM5/0.1, nbr 10.10.11.5
    FastEthernet3/0.1    ldp      swap to 55, push 42 on ATM5/0.1, nbr 10.10.11.5

Traffic that arrives on either interface, 2/0.1 or 3/0.1, is forwarded to the remote peer with the same label stack (55, 42). Traffic from the remote peer with label 53 is forwarded to one of the two shim interfaces; the ECMP algorithm determines which of the two shim interfaces receives the traffic.

In the case of a local cross-connects configuration, the following commands illustrate how a three-way cross-connect is created when 10.9.1.2 is a local address:

host1(config)#interface atm 6/0.101 point-to-point host1(config-subif)#mpls-relay 10.9.1.2 600001 host1(config-subif)#exit host1(config)#interface atm 6/2.101 point-to-point host1(config-subif)#mpls-relay 10.9.1.2 600001 host1(config-subif)#exit host1(config)#interface atm 6/2.103 point-to-point host1(config-subif)#mpls-relay 10.9.1.2 600001

This configuration results in the following forwarding table:

    host1:two# show mpls forwarding brief
    Platform label space
    …
    L2transport
         Interface        Owner                                            Action
    -------------------- -------- -------------------------------------------------------------------
    ATM6/0.101           ldp      l2transport to ATM6/2.101
                                  l2transport to ATM6/2.103
    ATM6/2.101           ldp      l2transport to ATM6/0.101
                                  l2transport to ATM6/2.103
    ATM6/2.103           ldp      l2transport to ATM6/0.101
                                  l2transport to ATM6/2.101

Traffic that arrives on interface 6/0.101 is forwarded by means of ECMP to both interface 6/2.101 and interface 6/2.103. Traffic that arrives on interface 6/2.101 is forwarded by means of ECMP to interface 6/0.101 and interface 6/2.103. Traffic that arrives on interface 6/2.103 is forwarded by means of ECMP to interface 6/0.101 and 6/2.101.