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neighbours

What exactly does it take for routers to become neighbours for eigrp, Do they have to be on the same ip subnet, say there is 4 routers, would they all be neighbours with each other ?

5 REPLIES
Purple

Re: neighbours

Hi Carl,

For EIGRP neighbors to form, the following must be common between them:

- they must belong to the same IP subnet

- they must be configured for the same AS number

Hope that helps - pls do remember to rate posts that help.

Paresh

New Member

Re: neighbours

if they were all on the same lan, would they all be neighbours ? and adjacent ?

Purple

Re: neighbours

Thanks for starting to rate posts, Carl.

If the routers are all on the same LAN (and satisfied the above requirements), they will be both both adjacent and neighbors. In fact, EIGRP has a much simpler concept of an adjacency than OSPF and we normally only speak about neighbors in EIGRP, not adjacencies. Unlike OSPF, you do not have the concept of neighbors that are not adjacent.

Hope that helps - pls do remember to rate posts that help.

Paresh

New Member

Re: neighbours

Thanks for that, I gather with eigrp it sends updates to all the routers on the same lan/subnet ?

Purple

Re: neighbours

That is absolutely correct. As soon as a change occurs in the network, which results in the change of a metric or next-hop for a route, EIGRP will send updates to all neighbors.

The split-horizon rule, however, forbids EIGRP from sending out updates on the interface that they were received from in the first place. That is the issue that you are running into here.

Out of curiosity, did you implement the config I suggested earlier ?

Your rating of posts is very much appreciated.

Paresh

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