Configuring Association Between VRRP and Peer BFD to Implement a Rapid Active/Standby Switchover
Context
When a VRRP group is faulty, the backup with the highest priority detects the fault and switches to the master after the Master_Down_Interval timer expires. The switchover period is at least 3s. During this switchover period, service traffic is still sent to the original master, causing loss of user traffic. In Figure 3-14, a peer BFD session is configured between SwitchA and SwitchB and used to rapidly detect communication faults of the VRRP group. When the BFD session detects a fault, an active/standby switchover is triggered immediately. This millisecond-level switchover reduces traffic loss.
After the fault is rectified, the VRRP group status on SwitchA and SwitchB is restored through VRRP negotiation.
A VRRP group can be associated only with a static BFD session or a static BFD session with automatically negotiated discriminators.
The master and backup in the VRRP group must work in preemption mode. It is recommended that the preemption delay be 0 on the backup and non-zero on the master.
Multiple VRRP groups can monitor a BFD session, and a VRRP group can monitor a maximum of eight BFD sessions simultaneously.
Procedure
- Configure a static BFD session or a static BFD session with automatically negotiated discriminators. For details, see Configuring Single-Hop BFD, Configuring Multi-Hop BFD, and Configuring Static BFD with Automatically Negotiated Discriminators.
- Run system-view
The system view is displayed.
- Run interface interface-type interface-number.subinterface-number
The view of the sub-interface on the backup where the VRRP group is configured is displayed.
- Run vrrp vrid virtual-router-id track bfd-session { bfd-session-id | session-name bfd-configure-name } peer
Association between a VRRP group and a peer BFD session is configured.
When associating a VRRP group with a BFD session, note the following points:
If session-name bfd-configure-name is specified, a VRRP group can be bound only to a static BFD session with automatically negotiated discriminators.
If bfd-session-id is specified, the VRRP group can be bound only to a static BFD session.
If a VRRP group is bound to an mVRRP group, the mVRRP group maintains the VRRP group status, and the VRRP group is unable to monitor any BFD sessions.