Asymmetric routing due to floating static being redistributed into OSPF

Unanswered Question
Jul 23rd, 2007

I am have asymmetric routing issue in a multi-homed environment due to redistributing floating into OSPF. We have a client with dual feed, 10MB primary and ADSL as backup. The primary is running BGP advertising the client ip space. HSRP with route tracking feature is used for fail over. The fail over seems to work fine but inbound traffic to client network seems to be taking the ADSL and the primary is used for outbound traffic from client network. I can see why i am having asymmetric routing as the bgp route is not installed into routing table because the floating static is redistributed into OSPF and inheriting AD for OSPF even though floating static has higher AD then BGP route. I would really appreciate if someone can advise me on possible resolution.

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Richard Burts Mon, 07/23/2007 - 11:26

Nav

Perhaps I am not understanding something in your post. But it seems to me that there are 2 solutions that should work. You could try setting the administrative distance of the floating static to be higher than both BGP and OSPF. Or you could try modifying the redistribute statement to use a route map or a distribute list and deny redistribution of the floating static.

If those do not solve the problem then perhaps you can clarify the environment and the problem.

HTH

Rick

vital-group Fri, 08/03/2007 - 06:35

Thanks for your reply Rick. We have now changed our routing architecture. OSPF is used for loopback and infrastructure and BGP is used to carry the customer routes. I will be testing the failover for the client in two weeks.

vital-group Tue, 08/28/2007 - 06:58

Hi Rick

Am still having asymmetic routing problem even after introducing the new BGP and OSPF infrastructure. BGP is used to carry customer routes via redistributing connected and static. The problem i am having currently for some clients is that there primary link is being used for outbound traffic and ADSL is used for inbound traffic. If you take a look at the network diagram i have attach i have two static routes pointing to the customer network. On Access1 router the static route has a default AD and on the Aggr1 the static route has AD of 250. The routing decision on the Core seems to be preparing ADSL route for some reason. I believe this may be due to bgp is assigning AD for static route when redistributed into BGP. Rick can you please help me resolve this problem without having to introduce BGP on customer primary router.

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