184
<SwitchB> terminal monitor
<SwitchB> debugging vrrp fsm
<SwitchB> debugging bfd ntfy
# When Switch A fails, the following output is displayed on Switch B.
*Dec 17 14:44:34:142 2014 SwitchB BFD/7/DEBUG: Notify application:TRACK State:DOWN
*Dec 17 14:44:34:144 2014 SwitchB VRRP4/7/FSM:
IPv4 Vlan-interface2 | Virtual Router 1 : Backup --> Master reason: The status of the
tracked object changed
# Display detailed information about the VRRP group on Switch B.
<SwitchB> display vrrp verbose
IPv4 Virtual Router Information:
Running Mode : Standard
Total number of virtual routers : 1
Interface Vlan-interface2
VRID : 1 Adver Timer : 100
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 Switch A fails, the Track module notifies VRRP to
change the status of Switch B to master. The backup can quickly preempt as the master without
waiting for a period three times the advertisement interval plus the Skew_Time.
Configuring BFD for the VRRP master to monitor the uplinks
Network requirements
As shown in Figure 46:
• Switch A and Switch B belong to VRRP group 1. The virtual IP address of VRRP group 1 is
192.168.0.10.
• The default gateway of the hosts in the LAN is 192.168.0.10.
Configure VRRP-Track-BFD collaboration to monitor the uplink on the master and meet the following
requirements:
• When Switch A operates correctly, the hosts in the LAN access the Internet through Switch A.
• When Switch A detects that the uplink is down through BFD, Switch B can preempt as the
master. The hosts in the LAN can access the Internet through Switch B.