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BGP fast-external-fallover vs BFD

Ravi Pande


I was studying on bgp performance and I came across "bgp fast-external-fallover" and BFD. I am confused because both achieve the exact same thing. Could anyone please let me know when we should "bgp fast-external-fallover" over BFD or vice versa.



1 Reply 1

paul driver
VIP Expert VIP Expert
VIP Expert

BFD can be tweak to failover in millseconds for route convergence with the added benefit it can be applied to most of the routing protocols so isn’t tied to any one.

Where’s as BGP fast-failover can work on just the router you apply it to, BFD needs to be applied to all directly connected neighbors/peers

Fast-failover is specific to the bgp protocol and only is subject to the loss of ebgp peers, Its has a related feature named "neigbour fall-over" which will accommodate both ebgp/Ibgp loss and if associated with low bgp hold times it can provide a quick response to a bgp link failure, However both features can be dependent on bgp's under lying routing protocol to also converge quickly especially  regards any of its non direct ebgp (loopback) and ibgp peers.

You could then if you wish implement both of these bgp/bfd features to work in tandem for a faster route convergence and failover.

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