H3C Technologies H3C S10500 Series Switches - Manual (Page 187)

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Master IP : 10.1.1.2
The output shows that when a fault is on the link between Switch A and Switch C, the priority of Switch
A decreases to 80. Switch A becomes the backup, and Switch B becomes the master. Packets from Host
A to Host B are forwarded through Switch B.
Configuring BFD for a VRRP backup to monitor the master
Network requirements
• As shown in
Figure
48 , Switch A and Switch B belong to VRRP group 1, whose virtual IP address
is 192.168.0.10.
• The default gateway of the hosts in the LAN is 192.168.0.10. When Switch A works normally, the
hosts in the LAN access the external network through Switch A. When Switch A fails, the hosts in the
LAN access the external network through Switch B.
• If BFD is not configured, when the master in a VRRP group fails, the backup cannot become the
master until the configured timeout timer expires. The timeout is generally three to four seconds,
which makes the switchover slow. To solve this problem, VRRP uses BFD to probe the state of the
master. Once the master fails, the backup can become the new master in milliseconds.
Figure 48 Network diagram for monitoring the master on the backup
Internet
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
L2 switch
VRRP packets
BFD probe packets
Configuration procedure
1. Create VLANs, and assign corresponding ports to the VLANs. Configure the IP address of each
VLAN interface as shown in Figure 48 . (Details not shown)
2. Configure VRRP on Switch A.
<SwitchA> system-view
[SwitchA] interface vlan-interface 2