Monday, May 7, 2012

Ethernet over MPLS (EoMPLS) Cisco Configuration Makes Simple

Ethernet over MPLS (EoMPLS) is part of Cisco's Any Transport over MPLS to provide L2 connectivity (pseudo-wire) over MPLS cloud. If you wish to extend EoMPLS on L3 VLAN interface (SVI-based EoMPLS or SwEoMPLS), you must have an OSM or an Enhanced FlexWAN module on the MPLS core-facing interface. Otherwise, you can configure PFC-based EoMPLS on a physical interface or sub-interface. In this example, we would use PFC-based EoMPLS on Cisco IOS 15.x, as I believe most of us won't have any special interface cards. Consider this network diagram below. We'll extend L2 connectivity on VLAN 10 to connect both servers over the MPLS cloud.

Here, we assume that basic MPLS configuration has been put in place. Configuring EoMPLS would be pretty straightforward.

On both PE1 and PE2 routers:

interface GigabitEthernet0/1.10
encapsulation dot1Q 10
xconnect 10.1.1.x 10 encapsulation mpls
no shut

Replace above 'x' with the peer PE router ID i.e. on PE1 x = 2 and on PE2 x = 1. The router ID is determined by the "mpls ldp router-id" command on the router.

On both CE1 and CE2 switches, let's assume Gi0/1 switch interface is used to connect to their respective PE routers.
Vlan 10
  name EoMPLS
interface GigabitEthernet0/1
switchport trunk encapsulation dot1Q
switchport mode trunk
interface GigabitEthernet0/2
description Host port
switchport mode access
switchport access vlan 10

To verify the EoMPLS connectivity, enter "show mpls l2transport vc" on both PE routers. The status should indicate UP. You can also perform "show spanning tree vlan 10" on both CE switches to ensure the sanity of spanning tree i.e. only one of the switches should be the root. And finally, both hosts should be able to ping each other on same IP subnet. For further details, refer to this Cisco article.


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