[c-nsp] Multicast between VRFs within a single router, probably an ASR9K

[Vijay Ramcharan]

John, 
I'm no multicast expert having had no operational experience with it. 

Have you looking into MVPN Extranets? 
See http://www.cisco.com/en/US/docs/ios/12_2sb/feature/guide/extvpnsb.html 

I think this is what you are trying to do by having one VRF contain your multicast sources (the extranet VRF) and the other VRFs be receivers. Wish I could lab it up but time doesn't permit. 

The provider network depicted in the link above is collapsed onto your single ASR so it should probably still work as I don't think it matters that you only have a single P/PE router. 

> -----Original Message-----
> From: cisco-nsp-bounces at puck.nether.net [mailto:cisco-nsp-
> bounces at puck.nether.net] On Behalf Of John Neiberger
> Sent: Wednesday, March 09, 2011 3:01 PM
> To: cisco-nsp at puck.nether.net
> Subject: [c-nsp] Multicast between VRFs within a single router, probably an
> ASR9K
> 
> I have a lab situation where we would really benefit from being able
> to get multicast receivers in one VRF to join multicast sources in a
> different VRF, all on the same router, probably an ASR9K. We've
> thought of a couple ways to do this. One is to offload the source VRF
> to another box and then use subinterfaces on the trunk links with each
> subinterface in a different VRF. That would work just fine, but it
> would mean that each new receiver VRF would increase the bandwidth
> usage on the trunk. We'd end up with the same multicast streams being
> duplicated several times over on those links.
> 
> Another method would be to just run cables between the VRFs. That
> would work well, but it would eat up ports quickly, especially since
> we'll probably need a few gig per VRF.
> 
> I'd really like to find a way to do this within the box. I've already
> gotten unicast to work by using BGP to redistribute between the VRFs
> in a sort of VRF Lite configuration. However, I can't get multicast to
> work across the VRF boundaries. MDT doesn't seem like an option
> because I'm not doing mpls and this is all happening within one box,
> not from PE to PE or anything like that, and we're trying to go from
> one VRF to another, which I don't think MDT would allow us to do.
> 
> It sure seems like there should be a way to make this work, but I'm
> not that familiar with VRFs, and I'm definitely not that familiar with
> trying to do multicast across VRFs. In the end, we don't even need
> unicast redistribution at all. We want to have separate VRFs for each
> virtual lab, and those VRFs just need to be able to pull multicast
> sources from the source VRF. There will be no unicast traffic at all.
> 
> This is purely for a lab environment at work for testing various video
> encoding/compression systems. We wouldn't be thinking of attempting
> this in a production environment, but it sure would solve some
> problems for us if we could pull it off in the lab area.
> 
> Any thoughts?
> 
> Thanks!
> John
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