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Migration with MPLS core


Our company (AA) have just bought another company (BB). We are considering the migration solution. AA is running MPLS VPN over LSP tunnel while BB is running MPLS VPN over L2TP tunnel. Some one suggest to use CsC model and others prefert Inter-AS model. Could expert here give some pieces of advice for that? I am considering how to deploy MPLS QoS/TE, Multicast or AtoM / VPLS in such complex models. Are there any limitation or weakness of CsC/Inter-AS model?

Thanks in advance


Re: Migration with MPLS core


the question about technology should be considered at a later stage in redesign.

The first question is: what are the requirements and constraints.

Nevertheless, InterAS is probably what I would opt for knowing nothing about requirements and constraints. You have two companies, which should communicate now. Peering seems the natural choice.

There is InterAS MPLS TE and QoS can also be implemented. AToM and VPLS can also be done. The "peering" in the latter case has to be done through normal interfaces/LAN switches.

In any case knowing the final picture would greatly help in figuring out a proper migration path. (Reminds me of a management joke: "We are not yet sure where we are going, but we will for sure be first!")

Hope this helps


P.S.: personal opinion: MPLS is about labels, and this is the direction of Cisco and all other vendors. So MPLS over L2TP sounds like a workaround for "the real thing". MPLS with label switching in the core is more main stream and therefore it is more easy to get qualified help, experienced workforce, etc.

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Re: Migration with MPLS core

Thank you Martin!

Finally we all agree to merge in a single MPLS domain. We just want to make things simple and also it is good for deploy MPLS TE/Multicast and VPLS in the future. L2TPv3, CsC and Inter-AS all will be moved out of the design.

Thank you again.

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Re: Migration with MPLS core

These are actually two different models..

Inter-AS according to the option used might not solve your problem. If you use option B ( Change NH at ASBR ) then certain things will not work i.e Multicast, latency based network not preserved ( Could use MED )..

CsC..Where is your BGP infrastructure in this model???

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