EIGRP Question ...

Unanswered Question
May 16th, 2007


I would just like to confirm this scenario ....

Router A is running EIGRP with AS number 20 and is advertising network

in its EIGRP.

The configuration is as follows :-

router eigrp 20


no auto-summary

Router B is another router that is connected to Router A and its configuration is as follows :-

router eigrp 20



no auto-summary

My question is that [1] Router A would know network since it would be advertised to it by Router B right ?

[2] It is redundant to advertise network in router A right ? It is okay to do so but it is not necessary as router B would advertise this network to Router A isn't it ...

Pls advice,

Thank you,

- sn -

I have this problem too.
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mohammedmahmoud Wed, 05/16/2007 - 03:29


[1] yes, EIGRP should do this.

[2] I can't get what you mean, but any way as long as router B sends it to router A, router A will advertise it to any other connected routers.

NOTE: Network command should be used to advertise direct connected interfaces, thus it can't be done on router A, as this IP is not for an interface connected to router A.

HTH, please do rate all helpful replies,

Mohammed Mahmoud.

Jon Marshall Wed, 05/16/2007 - 03:35


Just to add to Mohammed's post. By entering under the EIGRP confgiuration you are not telling EIGRP to advertise the network. You are telling EIGRP on which interfaces to start EIGRP on.

Hence Mohammed's point about if there is no interface you shouldn't include the network statement under EIGRP.



mohammedmahmoud Wed, 05/16/2007 - 03:40


Jon is totally right, always keep in mind that the network command for all routing protocols (except BGP) is used to tell the routing process which interface shall it run on and send in its updates (but note that the updates will use the subnet mask of the interface not the subnet mask of the network command).


Mohammed Mahmoud.


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