3Com S7906E Configuration Manual page 628

Switch A is connected to Switch C through Switch B. VLAN-interface 100 on Switch A,
VLAN-interface 200 on Switch C, and VLAN-interface 200 and VLAN-interface 100 on Switch B run
RIP process 1.
Configure a static route to Switch C on Switch A, and configure a static route to Switch A on Switch
C. Enable BFD on VLAN-interface 100 of Switch A and VLAN-interface 200 of Switch C.
Switch A is connected to Switch C through Switch D. VLAN-interface 300 on Switch A runs RIP
process 2; VLAN-interface 400 on Switch C, and VLAN-interface 300 and VLAN-interface 400 on
Switch D run RIP process 1.
Enable static route redistribution into RIP on Switch A and Switch C so that Switch A and Switch C
have routes to send to each other. Switch A learns the static route sent by Switch C, the outbound
interface is the interface connected to Switch B.
When the link between Switch B and Switch C fails, BFD can quickly detect the link failure and
notify it to RIP, and the BFD session goes down. In response, RIP deletes the neighbor relationship
with Switch C and the route information received from Switch C. Then, Switch A learns the static
route sent by Switch C, the outbound interface of the route is the interface connected to Switch D.
Figure 1-9 Network diagram for configuring BFD for RIP (bidirectional detection in BFD control packet
mode)
192.168.3.2/24
Vlan-int300
192.168.3.1/24
Vlan-int100
192.168.1.1/24
192.168.1.2/24
Switch A
Configuration procedure
1) Configure an IP address for each interface (Omitted)
2) Configure RIP basic functions and enable static route redistribution into RIP so that Switch A and
Switch C have routes to send to each other.
# Configure Switch A.
[SwitchA] rip 1
[SwitchA-rip-1] network 192.168.1.0
[SwitchA-rip-1] peer 192.168.2.2
[SwitchA-rip-1] undo validate-source-address
[SwitchA-rip-1] import-route static
[SwitchA-rip-1] quit
[SwitchA] interface vlan-interface 100
[SwitchA-Vlan-interface100] rip bfd enable
[SwitchA-Vlan-interface100] quit
Switch D
Vlan-int300 Vlan-int400
192.168.4.1/24
Switch B
Vlan-int200
192.168.2.1/24
Vlan-int100
BFD
1-30
Vlan-int400
192.168.4.2/24
Vlan-int200
192.168.2.2/24
Switch C