Multicast MPLS VPN, Inter-AS without MDT!!!

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Jun 26th, 2007
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Hi Group,,,

I have the following solution:










? IPv4 Unicast is working fine between CE1 and CE2 over a MPLS VPN from PE1 to PE2.

? No MDT could be used in the MPLS VPN

? PIM is able from PE1 to PE2 but RP information is not being send between ASBR1.

? ASBR1 is RP for AS1

? ASBR1 is RP for AS2

? The subnet /30 between ASBR1 and ASBR2 is not in the IGP of AS1 and AS2.(Best Practices, BGP Next-Hop-Self in ASBR)

? Inter-AS MPLS between ASBR1 and ASBR2, Option: Using /30 subnet between ASBR`s.


1. In order to have ?PIM Tree? from PE1 to PE2? I need to redistribute the /30 (ASBR1----ASBR2). How Can I do it?

Option a: Redistribution from Connected to IGP

Option b: AFI IPv4 Multicast

Do you have other solution?

2. Since I can?t use MDT, GRE Tunnel between CE1 and CE2 is the solution. Do somebody have been implemented it?

3. RPF Check fail when I use a GRE Tunnel between CE1 and CE2?

4. Do you know another solution to have Multicast in a VPN without MDT?


Sergio Jim?nez Arguedas

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swaroop.potdar Tue, 06/26/2007 - 14:07
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Can you post your config in a zippped file.

And also why are you not able to use mdt, if you are using a earlier IOS you can upgrade it.



Harold Ritter Wed, 06/27/2007 - 11:38
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1) I'm not sure I understand why you would need to redistribute the /30 between ASBR1 and ASBR2 in the IGPs to get it to work.

2) When you say MDT, do you mean mVPN. If so, what are the reasons you can't use it.

3) You probably need to use a static mroute pointing at the tunnel interface or run an IGP over the tunnel for the RPF to succeed.

4) Beside mVPN and multicast over gre tunnels, you could also do multicast over l2vpn.

Hope this helps,

sejimenez Thu, 06/28/2007 - 13:45
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Hi,,, Hritter

1. The /30 in the AS Local IGP is because a I have Multicast between PE1-PE2. In order to have MPLS VPN Multicast I dont need the /30 in the Local IGP.

2.I can not use MDT because AFI MDT is not supported in the ASBR. I think in the SP Lab the IOS does not support this feature. Just look the IOS in the blueprint... What do you think?

3. Sure,,, I have solvent the issue!!! Document... Multicast over a GRE Tunnel.

4. Also I can do a L2VPN to MCast!!!

I have been searching information and this solution of MCastoGRE between CE-CE,,, was used before MDT.


Sergio Jim?nez A.

Harold Ritter Thu, 06/28/2007 - 15:21
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1) Without knowing which InterAS option you are using (10a, b or c), there is nothing that forces you to inject the /30 between ASBR1 and 2 in the IGP.

2) You can run mVPN in an InterAS context without MDT SAFI. This would require to run MSDP between the two ASes.

3) Great.

4) You can certainly use Mcast over l2vpn but mVPN (or Mcast over l3vpn) would definitely scale better.

Hope this helps,


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