BGP in Dual Homing setup not failing over correctly

[marioderosa2008]

Hi all,

we have dual homed BGP connections to our sister company network but the failover testing is failing.

If i shutdown the WAN interface on the primary router, after about 5 minutes, everything converges and fails over fine.

But, if i shut the LAN interface down on the primary router, we never regain connectivity to the sister network.

Our two ASR's have an iBGP relationship  and I can see that after a certain amount of time, the BGP routes with a next hop of the primary router get flushed from BGP and the prefferred exit path is through the secondary router. This bit works OK, but i believe that the return traffic is still attempting to return over the primary link...

To add to this, we have two inline firewalls on each link which are only performing IPS, no packet filtering.

Any pointers would be great.

thanks

Mario                

[marioderosa2008]

Hi John,

I think that BGP conditional advertisement feature will solve my issue.

I can advertise the summary on condition that a specific prefix exists in the BGP routing table.

That way when the LAN goes down, the prefix will not be in BGP so the summary advertisement should stop.

Hoping to set this up at the weekend.

Mario

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