Cisco Catalyst 4500 series Administration Manual page 938

Configuration Examples for Bidirectional Forwarding Detection
In this example, the EIGRP network contains SwitchA, SwitchB, and SwitchC. Gigabit Ethernet
interface 6/1 on SwitchA is connected to the same network as Gigabit Ethernet interface 6/1 on SwitchB.
Gigabit Ethernet interface 6/1 on SwitchB is connected to the same network as Gigabit Ethernet interface
6/1 on SwitchC.
SwitchA and SwitchB are running BFD Version 1, which supports echo mode, and SwitchC is running
BFD Version 0, which does not support echo mode. We would say that the BFD sessions between
SwitchC and its BFD neighbors are running echo mode with asymmetry. This is because echo mode will
run on the forwarding path for RouteA and SwitchB, and their echo packets will return along the same
path for BFD sessions and failure detections, while their BFD neighbor SwitchC runs BFD Version 0
and uses BFD controls packets for BFD sessions and failure detections.
Figure 39-3
are running EIGRP as their routing protocol.
Figure 39-3
Gigabit Ethernet 6/2
The example, starting in global configuration mode, shows the configuration of BFD.
Configuration for SwitchA
interface GigabitEthernet6/2
no switch
ip address 10.4.9.14 255.255.255.0
!
interface GigabitEthernet6/1
no switchport
ip address 172.16.1.1 255.255.255.0
bfd interval 100 min_rx 50 multiplier 3
no shutdown
!
router eigrp 11
network 172.16.0.0
bfd all-interfaces
auto-summary
!
ip default-gateway 10.4.9.1
ip default-network 0.0.0.0
ip route 0.0.0.0 0.0.0.0 10.4.9.1
ip route 172.16.1.129 255.255.255.255 10.4.9.1
!
Configuration for SwitchB
!
Software Configuration Guide—Release IOS XE 3.6.0E and IOS 15.2(2)SG
39-18
shows a large EIGRP network with several switches, three of which are BFD neighbors that
EIGRP Network with Three BFD Neighbors Running V1 or V0
172.16.1.1
GigabitEthernet 6/1
RouterA
Chapter 39
Gigabit Ethernet 6/2
Gigabit Ethernet 6/2
RouterB
172.16.1.2 Gigabit Ethernet 6/1
172.16.1.3
GigabitEthernet 6/1
Configuring Bidirection Forwarding Detection
Gigabit Ethernet 6/2
RouterC
OL_28731-01