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EIGRP to BGP redistribution/summarization problem

Having a question for you all. We are redistributing between some external BGP routing to our internal EIGRP routing processes on two border routers that connect to this external network. These two routers are in different locations.

The problem is this. We want to summarize the EIGRP routes as they go out to the BGP network and by using the "aggregate-address" with the "summary-only" option that part is working fine. However, as an unintended consequence, these routes are then included in the redistribution back into EIGRP. I would rather this not happen.

I was thinking we could set up a route map on the "aggregate-address" command using the "advertise-map" option that set a tag on the route, which we would then look for in EIGRP and not let back into the routing tables. However, when I try this I get the error message:

"ROUTE-MAP" used as BGP advertise route-map, set tag not supported

Is there a better way of doing this that I'm not seeing? Any suggestions would be appreciated.

3 REPLIES

Re: EIGRP to BGP redistribution/summarization problem

Can you use a route map with the redistribute command in EIGRP and deny your native internal networks from being redistributed back into EIGRP from EBGP.

As far as your question about setting tags is concerned you should be able to tag the routes with a route map used with the redistribute command.

HTH

Sundar

Re: EIGRP to BGP redistribution/summarization problem

Yes, that is a thought, however, it does mean maintaining both the aggregation and the route-map. While this definitely would work, it just doesn't seem like the most efficient way, plus its prone to mistakes if someone updates one without the other.

Re: EIGRP to BGP redistribution/summarization problem

Hi,

I agree with Sundar, use route-map in redistribution, something like this:

With BGP you should use communities as you can't use tagging.

!

route-map eigrp-to-bgp deny 10

match tag 13

!

route-map eigrp-to-bgp permit 20

set community 65002:13 additive

!

route-map bgp-to-eigrp deny 10

match community 1

!

route-map bgp-to-eigrp permit 20

set tag 13

ip community-list 1 permit 65002:13

HTH,

Mohammed Mahmoud.

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