Multicast, L2TPv3,EoMPLS support

Unanswered Question
Apr 16th, 2007

My requirements are to support Multicast for future deployment and vlan extension over a MPLS ISP( ISP is provding ospf handoff)

I will have to use a software based solution since the tunnel needs to start and terminate on 3845s so L2tpv3 which is router-based solution is a good candidate.

Also EoMPLS does not support multicast I would have to use a GRE tunnel to provide support for multicast.

With MPLS over GRE with EoMPLS feature I am looking at a maximum mtu size of 1570 and if voice is deployed over this then each tiny voice packet will have a pretty big header compared to the header. here i would need to use an additional GRE tunnel for multicast support.

With L2TPv3 it would add 20 bytes of header.

So would l2TPv3 and a gre tunnel for multicast be a good design??

I am thinking using L2TPv3 for layer 2 extension and a GRE tunnel for multicast support.

I have this problem too.
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ariela Wed, 04/18/2007 - 23:03


it depends on your multicast application, and topology. Normally I've seen implemented the multicast transport over MPLS cloud in two ways:

1. Multicast over MPLS, using MDT like a GRE tunnel:

2. Multicast over VPLS istance (treated like a broadcast):

Today multicast is not label switched (last Farinacci draft is dated 2003).




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