redistributing BGP in Eigrp

[MARCELO MATURO]

I have the following problem. I have a router that is learning routes from a remote router by eigrp ( the same autonomous system) and by redistribute eigrp(from routes learned by a bgp router). I want to the route learned by the redistribute eigrp may be de primary. Y don?t know how to modify the distance so that the router is learning eigrp and external eigrp choose the last option.

This is the topology status:

IP-EIGRP (AS 300): Topology entry for 4.5.44.2/32

State is Passive, Query origin flag is 1, 1 Successor(s), FD is 20640256

Routing Descriptor Blocks:

1.4.4.29 (GigabitEthernet0/1), from 1.4.4.29, Send flag is 0x0

Composite metric is (20640256/20640000), Route is Internal

Vector metric:

Minimum bandwidth is 128 Kbit

Total delay is 25010 microseconds

Reliability is 255/255

Load is 15/255

Minimum MTU is 1500

Hop count is 2

1.4.4.50 (GigabitEthernet0/1), from 10.40.4.50, Send flag is 0x0

Composite metric is (2525696/2525440), Route is External

Vector metric:

Minimum bandwidth is 1024 Kbit

Total delay is 1010 microseconds

Reliability is 255/255

Load is 1/255

Minimum MTU is 1500

Hop count is 1

External data:

Originating router is 54.0.9.10

AS number of route is 65199

External protocol is BGP, external metric is 0

Administrator tag is 11664 (0x00002D90)

Thanks

Marcelo

[mike-greene]

Hi,

I believe if your running BGP and EIGRP on the same router and you would like to prefer the EIGRP learned routes over the BGP learned routes you can use the "distance bgp" command to raise the AD for the BGP routes to something like 200 for external , 200 for internal and 200 for local. If you would like to set only certain BGP routes and not all of them use the "distance " command and refer to an ACL for those certain routes. This example will only help if you?re dealing with the local router that BGP and EIGRP are running.

If your looking to make the routing decision two or three EIGRP hops away from the redistribution router then your going to have to adjust your seed metric in the eigrp config on the redistribution router with something like "default-metric 1 10000 1 255 1500". This will make the routes coming from BGP into EIGRP look bad metric wise and traffic will not head towards the BGP router.

I'm sure there are other ways to accomplish this with route maps etc but this is how I've done this in the past.

HTH's

[MARCELO MATURO]

Thank you Mike for your answer.

My situation is the second. Althougth I improve the metric y the redistribution router (redistribute bgp 65199 metric 10240 100 255 1 1500), the router neighbor eigrp of this one, allways choose another route because this route is external and the other is internal( distance 170 and 90)

Marcelo

[amarsjoshi]

Hi,

If the path to the destination is through the same physical interface, you dont have any options to get it to use external EIGRP routes over internal EIGRP routes..

Also, I am not sure how you are getting the same routes as internal and external both. Ideally, if you are redistributing a route from BGP into EIGRP then that route should not exist in EIGRP by any other means like (network x.x.x.x in EIGRP configuration) - Again, BGP will not advertise networks that dont already have routes present in the routing table..

Can you clarify ..

-Amar

[mike-greene]

Hi,

Sounds like he has two paths to the same network and he wants to force traffic over BGP (correct me if I'm wrong). Like he has a hub and spoke T1 network for backup but all the spoke sites have an MPLS connection running BGP exchanging local routes and hopefully using route maps to filter networks going out into the MPLS network twice.

If this is the case I would suggest using manual summarization on the backup T1's so the BGP routes have the longer prefix. The way you have your IP addressing setup per site will dictate if that will work or not.

[MARCELO MATURO]

Thanks, Amar.

Yes, The path to the destination is througth the physical interface. I will try to clarify with the graphic:

Router A Know routes of D by Eigrp.

Router B Know routes of D by BGP.

Router B redistribute bgp in Eigrp.

I need that router C knows primary routes of D through router B.

Thanks

[amarsjoshi · Accepted solution]

Thanks for the diagram it helps..

On B - do this :

!

router eigrp x

distance eigrp 90 80

!

This will cause all external routes also to have distance 80 which will be better than internal which will still be 90 -- this should solve it..

Or, you can keep both distances at 90 and manipulate the bandwidth or delay on A to get your result..

Also you should probably have the same config for distance on A, B and C this will help troubleshooting later on if you run into issues..

Let me know how it goes,

Thx

Amar

[MARCELO MATURO]

Thanks Amar,

I am trying to apply your solution. The eigrp is in the prodution enviroment, so that I am looking for a period of time to make the changes a testing this configuration.

Marcelo