Dell EMC SmartFabric OS10 User Guide Release 10.5.0

BFD for BGP example

In this BFD for BGP configuration example, Router 1 and Router 2 use eBGP in a transit network to interconnect AS1 and AS2. The eBGP routers exchange information with each other and with iBGP routers to maintain connectivity and accessibility within each autonomous system.

OS10(conf)# bfd enable
OS10(conf)# router bgp 1
OS10(config-router-bgp-1)# neighbor 2.2.4.3 
OS10(config-router-neighbor)# bfd
OS10(config-router-neighbor)# no shutdown 
OR 
OS10(conf)# bfd enable
OS10(conf)# router bgp 1
OS10(config-router-bgp-1)# bfd all-neighbors interval 200 min_rx 200 multiplier 6 role active

OS10(conf)# bfd enable
OS10(conf)# router bgp 2
OS10(config-router-bgp-2)# neighbor 2.2.4.2 
OS10(config-router-neighbor)# bfd 
OS10(config-router-neighbor)# no shutdown
OR 
OS10(conf)# bfd enable
OS10(conf)# router bgp 2
OS10(conf-router-bgp-2)# bfd all-neighbors interval 200 min_rx 200 multiplier 6 role active

BFD packets originating from a router are assigned to the highest priority egress queue to minimize transmission delays. Incoming BFD control packets received from the BGP neighbor are assigned to the highest priority queue within the control plane policing (CoPP) framework to avoid BFD packets drops due to queue congestion.

BFD notifies BGP of any failure conditions that it detects on the link. BGP initiates recovery actions.

BFD for BGP is supported only on directly connected BGP neighbors and in both BGP IPv4 and IPV6 networks. A maximum of 100 simultaneous BFD sessions are supported.

If each BFD for BGP neighbor receives a BFD control packet within the configured BFD interval for failure detection, the BFD session remains up and BGP maintains its adjacencies. If a BFD for BGP neighbor does not receive a control packet within the detection interval, the router informs any clients of the BFD session, and other routing protocols, about the failure. It then depends on the routing protocol that uses the BGP link to determine the appropriate response to the failure condition. The normal response is to terminate the peering session for the routing protocol and reconverge by bypassing the failed neighboring router. A log message generates whenever BFD detects a failure condition.