3Com S7902E, Configuration Manual

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The above output indicates that when BFD detects that Switch A fails, it notifies VRRP through the track
module to change the status of Switch B to master, without waiting for a period three times the
advertisement interval, so that a backup can quickly preempt as the master.
Configuring BFD for the VRRP Master to Monitor the Uplinks
Network requirements
z
As shown in Figure 1-4 , Switch A and Switch B belong to VRRP group 1, whose virtual IP address
is 192.168.0.10.
z
The default gateway of the hosts in the LAN is 192.168.0.10.
z
When Switch A works normally, the hosts in the LAN access the external network through Switch A.
When Switch A detects that the uplink is down through BFD, it decreases its priority so that Switch
B can preempt as the master, thus ensuring that the hosts in the LAN can access the external
network through Switch B.
Figure 1-4 Network diagram for monitoring uplinks using BFD
Internet
Master
uplink device
Backup
uplink device
Uplink
Virtual router
Virtual IP address:
192.168.0.10
Vlan-int2
192.168.0.101/24
Vlan-int2
192.168.0.102/24
Switch A
Master
Switch B
Backup
Vlan-int3
1.1.1.1/24
Vlan-int3
1.1.1.2/24
L2 switch
Uplink
VRRP packets
BFD probe packets
Configuration procedure
1) Configure BFD on Switch A.
# Configure the source address of BFD echo packets as 10.10.10.10.
<SwitchA> system-view
[SwitchA] bfd echo-source-ip 10.10.10.10
2) Create a track entry to be associated with the BFD session on Switch A.
# Create track entry 1 to be associated with the BFD session to check whether the uplink device with the
IP address 1.1.1.2 is reachable.
[SwitchA] track 1 bfd echo interface vlan-interface 3 remote ip 1.1.1.2 local ip 1.1.1.1
3) Configure VRRP on Switch A