Quick EIGRP question

[Ruterford]

EIGRP quick question:

If I summarize an eigrp route (say 172.16.0.0 /12) only on an interface facing some stub router in my network, does it mean that the same summary will be advertised by the non-stub router I did the summarization from, on any other non-passive interfaces that are part of the same EIGRP AS?

Thanks!

[Jon Marshall · Accepted solution]

Just to clarify - you mean if you apply "ip summary-address eigrp ....."  command on interface will that summary also get advertised out of any other interfaces ?

If so, no it won't, the summary address will only be sent to any EIGRP neighbors reachable via the interface you apply it on, in your case just the stub router.

Remember that using a summary address like this with EIGRP will insert a summary route with an AD of 5 into your hub's IP routing table. Just something to be aware of.

Jon

[paul driver]

Hello

No it will not as the summary you state is interface specific and not domain specific.

However If you applied auto summarization in the eigrp process (on by default) and advirtised by the network command then it could be advertised to all eigrp neighbors, be it stub or non-stub routers providing the route you are adverting is going to cross a network boundary between networks.

                             autosummary enabled

->(172.16.1.0/24)  RTR1 - (10.1.12.0/24) -> RTR2 (172.16.0.0/16)

                             autosummary disabled

->(172.16.1.0/24)  RTR1 - (10.1.12.0/24) -> RTR2 (172.16.1.0/24)

res

Paul

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Thanks.