multicast on Multi-VRF cofnigured router

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Sep 17th, 2009
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Hi,


is multicast is supported on Multi-vrf configured router? As I have two document where they are talking about the Multicast can be run on multi-vrf interface not running MPLS. Other doc is saying you can not run mulicast on interface running MPLS with multi-vrf cofniguration...


http://www.cisco.com/en/US/docs/ios/12_2sb/12_2sba/feature/guide/vrflite.html <--- look at the restriction.


http://www.cisco.com/en/US/technologies/tk648/tk828/tk363/technologies_white_paper0900aecd8012033f.html


Why is it not possible to run the MULTICAST on VRF LITE interface running with MPLS on it?


thanks,

Devang

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Harold Ritter Thu, 09/17/2009 - 17:07
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Devang,


I am not too sure what that second is referring to. Multicast is certainly supported in a multi-vrf (also know as vrf-lite) context as multicast is VRF aware.


Regards

devang_etcom Thu, 09/17/2009 - 17:16
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Hritter,


Thanks for your reply. The issue is will multicast work if we have MPLS between PE-CE link and CE is multi-VRF CE? According to me it will not...


AS well as I am trying to find out an application where we have MPLS running on PE-CE link and CE is multi-VRF interface (Interface facing to PE on CE router is also part of VRF)... any idea?


thanks,

Devang

Harold Ritter Thu, 09/17/2009 - 18:08
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Devang,



Why would you have MPLS on the PE-CE link? This is only required in certain corner cases (Carrier supporting Carrier for instance).


Multicast will work on the CE even if this CE is configured for multi-VRF.


Regards


devang_etcom Thu, 09/17/2009 - 18:51
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Hritter,


I trying to understand the same thing from the first link i posted in my first post. In that Cisco doc they are talking about MPLS between PE-CE link and also saying that IP Multicast will not be supported in restriction portion of the document. So there I have big confusion. I know Multicast works in PE-CE with multi-VRF CE but there it is saying IP Multicasting will not be supported when there is MPLS running on link between PE-CE link and CE is multi-vrf interface running VRF on interface facing to PE.


Thanks,

Devang

amit.bhagat Thu, 09/17/2009 - 17:32
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Hi All,


This Cisco document (the first one) suggests that in VRF-Lite, MPLS labels are exchanged between PE and CE. However, most books suggest no labels are exchanged between PE and CE, and no MBGP is required.


Here's an sample of the one I tested recently-

http://sites.google.com/site/amitsciscozone/home/mpls/multi-vrf-or-vrf


Is it important to run LDP/MBGP between PE and CE in VRF-Lite? What advantages you get if you run LDP/MBGP instead of not running one?


Please share your thoughts.


Amit.

devang_etcom Thu, 09/17/2009 - 17:37
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Amit,


According to me adding MPLS between PE-CE link with CE acting as Multi-VRF CE (PE facing interface is also in VRF) will not support the Multicast... then you will have to add full mesh of GRE between required sites to support the multicast...


even i am also looking for what are the advantages of running LDP/BGP on PE-CE link... if there is a case for CSC then its fine to have MPLS between PE-CE link but again MultiVRF CE with PE facing VRF interface will have issue with Multicast scalability...


waiting for an replies from different engineers to get clear view of it...


thanks,

Devang

ulatif Tue, 11/17/2009 - 01:55
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Multicast should work in both of the following scenarios:


1. CE doing VRF-Lite with no MPLS between PE-CE (assuming PE is doing MPLS towards core).


2. PE-CE doing MPLS i.e. CsC


Have you lab tested and found that this doesnt work?

IMO both of above should work.

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