Network requirements – H3C Technologies H3C SR8800 User Manual
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The output shows that when the status of the track entry becomes Positive, Router A is the master and
Router B the backup.
# Enable VRRP state debugging and BFD event debugging on Router B.
# When Router A fails, the following output is displayed on Router B.
*Dec 17 14:44:34:142 2008 RouterB BFD/7/EVENT:Send sess-down Msg,
[Src:192.168.0.102,Dst:192.168.0.101,GigabitEthernet3/1/1,Echo], instance:0,
protocol:Track
*Dec 17 14:44:34:144 2008 RouterB VRRP/7/DebugState: IPv4 GigabitEthernet3/1/1 | Virtual
Router 1 : Backup --> Master reason: The status of the tracked object changed
# Display the detailed information of the VRRP group on Router B.
IPv4 Standby Information:
Run Mode : Standard
Run Method : Virtual MAC
Total number of virtual routers : 1
Interface GigabitEthernet3/1/1
VRID : 1 Adver Timer : 1
Admin Status : Up State : Master
Config Pri : 100 Running Pri : 100
Preempt Mode : Yes Delay Time : 0
Auth Type : None
Virtual IP : 192.168.0.10
Virtual MAC : 0000-5e00-0101
Master IP : 192.168.0.102
VRRP Track Information:
Track Object : 1 State : Negative Switchover
The output shows that when BFD detects that Router A fails, it notifies VRRP through the track module to
change the status of Router 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 uplink
Network requirements
•
As shown in
, Router A and Router 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 Router A works properly, hosts in the LAN access the external network through Router A.
When Router A detects that the uplink is down through BFD, it decreases its priority so that Router
B can preempt as the master, ensuring that the hosts in the LAN can access the external network
through Router B.