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EIGRP multicast


I have an issue with an EIGRP speaker router. Actually the remote site is connected trough a network that does not allow multicast traffic. This makes the adjancencies being down.

I read about the "neighbor" command, which will make the router to send unicast hellos....

Has somebody hava an issue like this, where makes the EIGRP process to send Unicast Hellos instead of Multicast?


Cisco Employee

Re: EIGRP multicast

Using the neighbor statement would definitely be the way to go if the common subnet between the two routers doesn't support multicast.


Harold Ritter
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New Member

Re: EIGRP multicast

I've read that when using the neighbor command, the interfaces stop processing multicast at all. Will this not be an issue if I have the Central Site interface with subinterfaces? I mean, doing this will make the interface stop processing multicast, but I have some other remote sites which do support multicast....

Cisco Employee

Re: EIGRP multicast

Yes, Configuring neighbor command will stops EIGRP from processing inbound multicast EIGRP packet and will stop sending multicast EIGRP packet via that interface.

Can you explain your setup?...

Do you have different subnets for each remote site.?

While configuring neighbor command, we need to specify the interface as well. So If you have 2 remote site connected to different sub interface of your central site(each remote site will be in different subnet), configuring neighbor command for one remote site will not affect the other.

But if all the remote sites are in same subnet (Connected via same interface of central site), you may need to configure neighbor command for all neighbors.



New Member

Re: EIGRP multicast

Ok, thanks for your explanation...

The setup is a Central Router with subinterfaces for each remote site, an each subinterface has a different subnet. My ISP give me a L2 link from each remote site to the central site, so I configure a dot1q subinterface for each remote site.

I was worried about as all the remote sites ends in the same physical interface, using the neighbor command will stop processing ALL multicast traffic, for all subinterfaces....

thanks again....

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