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New Member

MVPN Between ASR9K and ME3600 Duplicating Multicast Packets

I have an MVPN that spans an ASR9K and ME3600s, using the Draft Rosen style with default and data MDTs and GRE tunneling.  Routing wise everything appears to be working fine.  The P and C multicast routing tables appear to be fine, and data MDTs are created appropriately.  In some instances I noticed that the multicast video I stream for testing was breaking up badly.  This was only the case when the sender was attached to a 3600 and the reciever to the ASR.  I did some sniffing, and the ASR, when it recieves the multicast over the proivder network, is duplicating every packet as it sends to the VRF.  Very stange, and I'm not sure how to diagnose what is going on.

Note that the opposite is not the case, if the multicast sender is connected to the ASR and the listener is off of a 3600 there is no problem, no packet duplication and the stream works fine.  The problem appears to be when the GRE encapsulated multicast packets arrive at the ASR and need to be de-encapuslated and sent to a VRF, they are duplicated for some reason and sent twice.  Any ideas?

Cisco Employee

Do you have redundant ASR9ks

Do you have redundant ASR9ks towards recevier?

Can you provide output below along with interface  facing CE and CORE and multicast source ip/multicast group.

admin show install active summary

admin show platform

show run

sh pim vrf <name> neighbor
sh pim int <name> detail

sh mrib vrf <name> route x.x.x.x

debug pim  vrf <name> protocol


Best Regards,


New Member

Thanks for the response.  Yes

Thanks for the response.  Yes, the ASR9K node is actually two ASR9Ks clustered together.  Is there a way for me to check whether this is causing the issue (without unclustering them)?

I won't be be able to get the info you requested until early next week.

Cisco Employee

You can run the "debug pim"

You can run the "debug pim" command I mentioned earlier and see if anything suspecious is happening.

Also since this is cluster. Do you have a bundle interface with interface in each rack going towards the receiver?

Best Regards,



New Member

"Also since this is cluster.

"Also since this is cluster. Do you have a bundle interface with interface in each rack going towards the receiver?"

Yes that is correct, the connection is a vlan subinterface on a bundle interface that composed of interfaces on each ASR chassis.  I haven't noticed traffic dupication on any of the other traffic going through the bundle, but most of the other subints are layer2.

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