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Redundant Multicast over GRE Tunnel suggestion.

Good Day all,

I have a scenario that i need to implement in the network and i need some suggestion befire i implement this into the network.

I have 2 sites with both sites running 2 router to act as a redundancy to each other.


redundany multicast link between 2 sites.

The only option i have right now is to use GRE tunnel over the ISP network.

My biggest concern is, if i enable pim sparse in all the tunnel interface, the multicast packet could be duplicated when reaching the receiver.

I need some suggestion where i can make sure only 1 tunnel is used at 1 time to forward the multicast packet over the GRE Tunnel.

attached is the topology of the network.

appreciate any assistance for this problem.


Cisco Employee

Redundant Multicast over GRE Tunnel suggestion.


Just enable PIM on all interfaces, you wont have duplicated multicast packet on the receiver. PIM assert is used to avoid duplicate on the last hub router.


Lei Tian

VIP Purple

Re:Redundant Multicast over GRE Tunnel suggestion.


apply BSR pim. This way you can define the candiate rp and mapping agent via prioity whichh will reseult in redundency also for your mc


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Community Member

Redundant Multicast over GRE Tunnel suggestion.

Thank you paul,

im looking into the solution right now. It seems like Cisco has its own solution using auto-rp. would you recommend that?

Community Member

Guys,This might be a little


This might be a little late, but i manage to get the Multicast over GRE with redundancy works like a charm :)

The setup is using Auto-RP and OSPF over the GRE tunnel. Make sure that the RP loopback IP is different from the Loopback that you use for the GRE Tunnel since is will cause the RPF leaning failed.

Other than that, just configure the mroute at the RP mapping router just to make sure the RPF learning is succefull.


Hope this help :)



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