Users Guide

1398 Bidirectional Forwarding Detection
BFD Example
This example configures BFD for a BGP peer session. BFD is only supported
in conjunction with BGP. The BGP configuration is taken from BGP
Redistribution of OSPF Example in the BGP Configuration Examples
section and is not explained further here. The fast-external-fallover is not
enabled in this example, as BFD will provide failure detection.
1 Enable the BFD feature. This step is mandatory before configuring or
enabling BFD:
console#config
console(config)#feature bfd
console(config)#interface te1/0/1
console(config-if-Te1/0/1)#switchport mode trunk
console(config-if-Te1/0/1)#switchport trunk native vlan 100
console(config-if-Te1/0/1)#exit
console(config)#ip routing
2 Configure a VLAN routing interface and enable notification to BGP on
routing connectivity failure.
(Optional) Configure BFD sessions parameter on the BGP peer link.
BFD echo mode is enabled first. Then the BFD control packet interval is
set to 1 second. This configuration will send echo packets every 100 ms. If
three consecutive control or echo packets are missed, the interface is
declared down. BGP fast external failover is disabled on the peer interface
as BFD will notify BGP if the routing peer is not reachable:
console(config)#vlan 10
console(config-vlan10)#exit
console(config)#interface vlan 10
console(config-if-vlan10)#ip address 172.16.65.1 /30
console(config-if-vlan10)#ip bgp fast-external-fallover deny
console(config-if-vlan10)#bfd echo
console(config-if-vlan10)#exit
console(config)#bfd slow-timer 1000
console(config)#ip routing
console(config)#ip route 0.0.0.0 0.0.0.0 172.16.65.2 name
'Default-Route'
console(config)#router bgp 3434
console(config-router)#bgp router-id 172.16.64.1