Ask the Expert:Concepts, Configuration and Troubleshooting Layer 2 MPLS VPN – Any Transport over MPLS (AToM)

[ciscomoderator]

With Vignesh R. P.

Welcome to the Cisco Support Community Ask the Expert conversation.This is an opportunity to learn and ask questions about  concept, configuration and troubleshooting Layer 2 MPLS VPN - Any Transport over MPLS (AToM) with Vignesh R. P.

Cisco Any Transport over MPLS (AToM) is a solution for transporting Layer 2 packets over an MPLS backbone. It enables Service Providers to supply connectivity between customer sites with existing data link layer (Layer 2) networks via a single, integrated, packet-based network infrastructure: a Cisco MPLS network. Instead of using separate networks with network management environments, service providers can deliver Layer 2 connections over an MPLS backbone. AToM provides a common framework to encapsulate and transport supported Layer 2 traffic types over an MPLS network core.

Vignesh R. P. is a customer support engineer in the Cisco High Touch Technical Support center in Bangalore, India, supporting Cisco's major service provider customers in routing and MPLS technologies. His areas of expertise include routing, switching, and MPLS. Previously at Cisco he worked as a network consulting engineer for enterprise customers. He has been in the networking industry for 8 years and holds CCIE certification in the Routing & Switching and Service Provider tracks.

Remember to use the rating system to let Vignesh know if you have received an adequate response. 

Vignesh might not be able to answer each question due to the volume expected during this event. Remember that you can continue the conversation on the  Service Provider sub-community discussion forum shortly after the event. This event lasts through through September 21, 2012. Visit this forum often to view responses to your questions and the questions of other community members.

[Vignesh Rajendran Praveen]

Hi Tenaro,

I dont think it would be completely right to conclude that the terms pseudowire & AToM are interchangeable. The Layer 2 MPLS VPN service is called as AToM whereas a pseudowire is the virtual circuit created between the two PEs without which offering AToM service is not possible.

Coming to the second part of your question, it is purely based on the customer needs & design on which we can choose between a L2 MPLS VPN solution or L3 MPLS VPN solution. There is no clear distinct winner between them. But generally the below three points are considered to be a plus for L3 MPLS VPN over to L2 MPLS VPN.

1) The CE device need not hold on to a huge amount of routing information, thereby helping the CPU on the device.

2) It is a more scalable solution.

3) Finally it makes any-to-any site connectivity possible.

I would like to stress one more time that we cannot conclude if L2 MPLS VPN is better than L3 MPLS VPN or if L3 MPLS VPN is better than L2 MPLS VPN as it is purely based on customer needs and design as mentioned earlier that we choose between them.

Thanks & Regards,

Vignesh R P