EIGRP Routing

Answered Question
Oct 8th, 2007

Hi Experts,

Currently I have 2 WAN Routers and I would like to manipulate where if this network A, it will goes to Router A, and network B, it will goes to Router B. Anyway to do this ?


Currently all the routes are thrown to Router A and Router B link is not utilised..


Thanks in advanced.



Correct Answer by Richard Burts about 9 years 4 months ago

Cindy


This information certainly gives us something to work with. Perhaps we need a bit more information. Would I be correct in assuming that both 16.11.4.0/24 and 16.11.8.0/24 are advertised to both routers and that the metric for both networks is better on router A than it is on router B?


Assuming that this is the case then I would suggest that you could achieve what you want by configuring an offset list on router A which will add to the metric of one of the routes and make the other router have a better metric for that destination. It might look something like this:

access-list 10 permit 16.11.8.0 0.0.0.255

router eigrp

offset-list 10 in


You would need to fill in the AS number of your EIGRP, the amount of offset to add to the metric to make the route worse on this router than on the other router, and the interface on which the advertisement is received.


HTH


Rick

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Jon Marshall Mon, 10/08/2007 - 03:14

Hi Cindy


Could you provide some more details in terms of addressing etc. There are a number of options such as influencing routes with distribute-lists/route-maps and using policy based routing but it's difficult to tell from your initial description.


Jon

Richard Burts Mon, 10/08/2007 - 04:39

Cindy


I agree with Jon that some additional information would be helpful. If network A and network B are destination addresses then perhaps manipulating the metrics (perhaps using offset lists or route maps and distribute lists) may accomplish what you want. If network A and network B are source addresses then what you want would be policy based routing which uses route maps to provide an over-ride to the normal routing decision.


It would also be helpful to know what is upstream of router A and router B. Are they running a dynamic routing protocol with upstream neighbors or do they have static default routes or what? This would also influence the alternatives that we would consider.


In my experience most of the time when people have an active upstream link and a backup (unused) upstream link and want to make use of both of them the answer turns out to be policy based routing.


HTH


Rick

cindylee27 Mon, 10/08/2007 - 20:49

Thanks Jon, Rick.


Well, the info as below:


- All the routers are using EIGRP Routing Protocol.

- network A and B are destination addresses and they are 16.11.4.0/24 and 16.11.8.0/24.


Not sure if this is enough..or any other infos u need can let me know..


Thanks.


Correct Answer
Richard Burts Tue, 10/09/2007 - 03:31

Cindy


This information certainly gives us something to work with. Perhaps we need a bit more information. Would I be correct in assuming that both 16.11.4.0/24 and 16.11.8.0/24 are advertised to both routers and that the metric for both networks is better on router A than it is on router B?


Assuming that this is the case then I would suggest that you could achieve what you want by configuring an offset list on router A which will add to the metric of one of the routes and make the other router have a better metric for that destination. It might look something like this:

access-list 10 permit 16.11.8.0 0.0.0.255

router eigrp

offset-list 10 in


You would need to fill in the AS number of your EIGRP, the amount of offset to add to the metric to make the route worse on this router than on the other router, and the interface on which the advertisement is received.


HTH


Rick

cindylee27 Wed, 10/10/2007 - 09:10

Metric is better on router A -

yup, you are right, Rick.


I will try the method as per your suggestion then.


Thanks again.


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