Two way Redistribution of EIGRP to BGP

Unanswered Question

I have a current need to perform two way redistribution of EIGRP to BGP. So the network is setup like this:

I have redundant paths between two locations. 1 of the paths is a 100MG optical ethernet. The other is a 45MG DS3 that goes to an MPLS at location 1 and a 3MG bonded pair of T-1's out of the MPLS to Location 2. I have 4 routers. 2 at each location (all 3845's). The mpls provider uses BGP and currently a routing protocol doesn't exist in my infrastructure that would be go across the 100MG connection so I planed on using EIGRP. So the MPLS links terminate to routers 1 & 2 and the Ethernet link goes between routers 3 and 4. I need to redistribute the protocols at routers 1 & 2 so as to provide redundant paths with emphisis obviously on the 100MG circuit. I'm having trouble finding information on how to succesfully weight the ethernet link and and make sure that the MPLS link stays there for the redundancy. I will use HSRP on the LAN side of these routers to create the HA for them.

I have this problem too.
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jay77jay77 Fri, 10/12/2007 - 00:30

I would recommend to use eBGP on both the links.The optical link will be having the shortest ASPATH, so it will be used as primary link and DS3 will be used as backup link.

Ahh so if I setup the routers between the optical link with their own private AS's and use BGP between? So with this setup would I have to have router 1 be neighbors with the MPLS as well as router 3. Router 3 would be neighbors with 1 and 4? Router 2 with the mpls and Router 4? Router 4 with router 2 and router 3? Thanks for all of your help.

bvsnarayana03 Fri, 10/12/2007 - 05:43

You may want to run BGP with the MPLS ISP as well as between the router at 2 locations i.e. R1, R2, R3 & R4. Then use local preference to prefer a better path out of AS. In your case, ethernet as best preferred & MPLS as backup.

Another method would be to use bgp default-route originate with variable metrics at 2 locations.

You may get better options from experts on this forum.

gaurav_thapar79 Fri, 10/12/2007 - 10:21


I have inferred the following points from aforesaid requirement.

1. 100Mb Optical link MPLS-PE to Location2.

2. DS3 electrical link MPLS-PE to Location 1.

3. 2xT1s =3Mb as p2p link between two locations.

If above scenario is correct, then please use eBGP with ISP and iBGP for internal routing. This would suffice your HSRP requirement as well.

please revert for further queries n rate the post.

Mohamed Sobair Fri, 10/12/2007 - 13:14


Why dont u use a confederation? you can setup IBGP on one location & another IBGP session on the other location. Between them u can setup (Intraconfederation) ebgp peers.

Redistribution is not recommended because it will not mainatain BGP attributes for the routes. with this setup whatever bgp attribute u enforce, it will be maiataind through your backbone routers

Since HSRP is a LAN protocol , you would still be able to run it on the lan.


Mohamed Sobair


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