Inter-As Multicast VPNs

Answered Question
Oct 1st, 2009

So let me get this right. If you share an IGP domain and your loopbacks for each individual PE are advertised into the IGP then you do not require the PIM RPF Vector feature?

I have this problem too.
0 votes
Correct Answer by Laurent Aubert about 7 years 2 months ago

You are correct.

You use PIM Vector if your P's doesn't know the loopback of the remote AS. In this case the PE will add the BGP next-hop address in the PIM Join which tells the P router to use this address and not the real Source address to determine its upstream interface. The RD is also added as the MDT table index on the ASBR is RD based (used with Option B).

HTH

Laurent.

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lbrooker Thu, 10/01/2009 - 14:03

ahhh I think i get this, its becuase of the next hop value right?

wsr17-kent-syd-test#sh ip pim mdt bgp

Peer (Route Distinguisher + IPv4) Next Hop

MDT group 239.232.0.17

2:20:1:203.194.30.61 203.194.30.61

2:10:1:203.194.30.62 192.168.17.1

Correct Answer
Laurent Aubert Fri, 10/02/2009 - 05:33

You are correct.

You use PIM Vector if your P's doesn't know the loopback of the remote AS. In this case the PE will add the BGP next-hop address in the PIM Join which tells the P router to use this address and not the real Source address to determine its upstream interface. The RD is also added as the MDT table index on the ASBR is RD based (used with Option B).

HTH

Laurent.

lbrooker Tue, 10/06/2009 - 22:26

Laurent

I have tested this and it works wonderfully. Thanks again for all your help mate.

Cheers

Mat

shivlu jain Sun, 10/04/2009 - 22:17

You are absolutely right. PIM RPF vector is required only that time when the internal information is not shared to the outer cloud. It is like the same case if you are not attending a class in school and on your behalf some one mark your present. :)

regards

shivlu jain

http://shivlu.blogspot.com

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