BGP loopback issue

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Sep 6th, 2007
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I have iBGP peering using loopback address ( router A and router B) between two routers

and ospf is configured in the internal segment and redistributed to ospf and manipulated the the metrics

for the best path selection . MED is configured ,so all the lan traffic will always take for communicating the MPLS cloud

( I have four networks ,, and If Router A lan segment failed users will be able to reach via RouterB to 172.17.84.X (Mpls cloud)

But in this case this is not happening properly .

1. If i shutdown the Loopback interface of RouterA i can able to reach 172.17.84.X. via RouterB

2. If a user in the 172.17 .X.X segment is not able to reach 172.17.84.x via RouterB

Kindly help me to findout a workaround solution for the above mentioned issue .



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Pavel Bykov Thu, 09/06/2007 - 09:13
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I don't think i understand your second point correctly. Users of 172.17 cannot reach 172.17.84 when router A loopback is shutdown?

can you posts config of routing protocols on both routers?

Is ospf redistribution done on both routers?

dinesh1977 Thu, 09/06/2007 - 12:32
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One of my remote site ihave 172.17.X.y network . When my lan connection and my Loopback of Router A down ,Iam not able to access the other remote site 172.17.84.X ( I think the problem is when the return traffic will reach to Router A bcos of MED.

Yes Ospf is redistributed on both the Routers.

Pls find the attched configurations of both Router A and Router B.

Thanks for your replay.

Calin Chiorean Sun, 09/30/2007 - 23:41
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Hello all!

First of all, sorry but I could not find the attached configuration.

Second, in the LAN side, how are this to routers A and B connected? A router to one OSPF router, and B router to another OSPF router? Or A and B are connected to the same OSPF router?

If you have 2 OSPF routers, them how are this 2 connected (I mean routing)? OSPF?

Because if you have 2 OSPF routers and A and B routers are not fully meshed connected, them you might have one segment of network connected to 1st OSPF router and another segment to the 2ns OSPF router.In this scenario if you don't have OSPF enable between this two OSPF routers, you don't have redundancy for your routes.



dinesh1977 Sun, 09/30/2007 - 23:46
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Hi Calin,

Thanks for the response..

The issue is solved with advertise-map command`. Now it is working ..



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