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New Member

Combining two EIGRP AS into one

Hello. I have inherited a network that has two EIGRP AS's. Each of the AS's are about equal size. One(AS20) is inside our firewall, one (AS10) is outside (don't ask!).

On the outside AS, one router serves as a hub to about 10 spoke routers. I have the link set up to move this outside hub router inside the firewall, thus bringing the entire network inside. I want to combine the AS's into the inside AS, as I cannot see any reason to run 2 AS's once they are all inside.

My strategy is to set up some static routes to use during the transition (for redundancy), change the link to move the outside hub router to the inside, then change the hub router and spoke routers that were moved inside to AS20. Then I would clear all routing caches, then take a look at routing tables. Next, if all is OK, remove the static routes previously entered.

Comments? Suggestions? When changing from AS10 to AS20 on the routers moved inside, should I add AS20 and then remove AS10, or will that matter? Should I work from the spoke routers inside to the hub, or from the hub router and then outside to the spoke routers? Some of the spoke routers being moved inside are each 3-4 hours drive away, so remote administration is my only answer.

Thanks in advance for your input.

2 REPLIES
Gold

Re: Combining two EIGRP AS into one

Sounds like a good plan. When it is small enough that you can put statics this is the best way to go. I would put the statics in until you managed to override all the eigrp routes in the routing table and then remove the eigrp. You can then start as though it were a blank router.

In the cases where you cannot key in all the statics or you have lots of route redistribution this type of conversion can be painful.

A recommendation on any remote router change is to put a reload in 15min in and then make all your changes. If you screw up since you have not saved anything it will go back to the working config and you can try again. Just be sure to cancel the reload when you think you have done it correctly

New Member

Re: Combining two EIGRP AS into one

Thank you for your input. Project completed over the weekend without any major problems. Thanks for the tip on the reload command. Even though it was not utilized, I felt better knowing we could fall back to previous config if all else failed. I will remember that for future projects. Thanks again.

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