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eigrp question

Senario : I have two sites A and B which are connected by a MAN running EIGRP. Both sites have an IPVPN router connecting to the other international offices over the WAN running BGP. The router at Site A is the primary. We have servers at both sites. Currently if a remote office wanted to access a server at Site A then the traffic originates from router at Site A but leaves via Site B. Is there a way to tweek EIGRP to force traffic to use it local gateway ?

5 REPLIES
Purple

Re: eigrp question

Hi,

What is probably happening is that the eBGP learned routes are being preferred over the EIGRP routes because eBGP has a better administrative distance (20) than EIGRP (20).

One thing you can do is to use the 'distance' command under the EIGRP process to selectively set the AD to be lower for destinations which you need to reach directly over the MAN. Take care not to do it for all EIGRP router or you might find the sites being use as transit to other sites, instead of using the IPVPN.

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

Paresh

Re: eigrp question

just as simple typo correction Paresh meant EIGRP (90) or EIGRP EX(170).

but, if it was a summary EIGRP would have an AD of 5.

besides that if you could give us more information on the routing configs that you have for these sites, we could be certain of what could have caused the problem.

vlad

Community Member

Re: eigrp question

Currently all the traffic is forced in and out of site A. But we want to configure it so that local hosts at Site A or B use their local gateway routers.

If the traffic originated from site A then it should leave from site A and vice versa for site B.

Only local traffic between sites A and B should traverse the MAN or if either IPVPN routers failed.

If the MAN failed localised traffic between A and B should be prevented from going across the WAN. Site of Origin has been configured in BGP to ensure that this does not happen.

Is there a way to configure BGP instead of re-configuring EIGRP metrics on the LAN to get traffic to use its local gateway router ? or is route sumarisation in EIGRP the only option as changing the metrics may be too risky.

Re: eigrp question

Hello, without much thinking about your scenario.

If you need to change default routing behaviour, you are probably talking about policy routing.

Not sure if this is really need in your case.

But with Policy routing you can configure routing based on source address, and then you can control the traffic the way you want.

http://www.cisco.com/warp/public/732/Tech/plicy_wp.htm

http://www.cisco.com/univercd/cc/td/doc/product/software/ios122/122cgcr/fqos_c/fqcprt1/qcfpbr.htm

To really know what you need, more info about your router configs will be needed.

Anyway HTH,

if it does, please rate this post.

Vlad

Community Member

Re: eigrp question

I have posted a diagram with this question now. Unfortunately this does not include details of Core/Access and Distribution switches at either site but the setup is identical at both regional sites.

I am not sure if policy routing is the way we want to go as this may cause performance issues on the network.

If we change the routing cost on the EIGRP network on the external switches links the routers to the IPVPN is this likely to have any adverse affects on the network ?

What checks do I need to make to ensure this would work ?

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