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BGP - iBGP, eBGP and EIGRP - route selection

I have the following set-up in my POCL:

5 routers in AS2, 3 routers in AS1

2 of the routers in AS2 (Sunbury-1 and Hockley-1) have serial links into one router (IR-1) in AS1. These two have an eBGP connection with IR-1; in addition, they have iBGP relationship with each other. The other 3 routers in AS2 are running EIGRP, and all routes on the eBGP routers are redistributed from BGP into EIGRP, and EIGRP into BGP.

What we want to happen, is for the routers to always use the eBGP route to each other, when available. If for some reason, these links go down, then they should use the back-up EIGRP routes.

What I have found, is that if the eBGP connection fails (i.e. I pull out the serial cable, or reset the eBGP peer); the route to the other router and 'internet' routes remain in the routing table as learnt from EIGRP. To force the routers to use the eBGP routes, I have to reset the EIGRP neighborships.

I don't understand: they are learning eBGP routes but preferring the EIGRP-learnt routes to the same networks. Shouldn't the AD value prevent this?

Grateful for all help/suggestions


Re: BGP - iBGP, eBGP and EIGRP - route selection

When you redistribute ebgp (20) into EIGRP (90) they become External EIGRP (170). This might be why you are seeing your internal EIGRP routes taking preference over your External EIGRP ones. Mutual redistribution between protocols is not looked upon as good practice. Hope this helps.



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