Configuring Association Between VRRP and BFD to Monitor the Uplink Status

Context

VRRP cannot detect faults on the uplink of a VRRP group, which may cause service interruption. In Figure 1, a VRRP group is associated with a BFD session on the master so that the BFD session monitors the uplink status of the master. When the BFD session detects a fault on the uplink, it notifies the VRRP group that the priority of the master needs to be decreased. Then an active/standby switchover is triggered immediately. This reduces the impact of the uplink fault on service forwarding.

When the fault is rectified, the original master restores its priority and becomes the master again to forward traffic.

BFD detects faults in milliseconds. Association between VRRP and BFD provides a rapid active/standby switchover.

Only the S5720-EI, S5720-HI, S5720I-SI, S5720S-SI, S5720-SI, S5735-S, S5735S-S, S5735-S-I, S5730-HI, S5730S-EI, S5730-SI, S5731-H, S5731-S, S5731S-H, S5731S-S, S5732-H, S6720-EI, S6720-HI, S6720S-EI, S6720S-SI, S6720-SI, S6730-H, S6730S-H, S6730-S, and S6730S-S support this function.
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.

Figure 1 Association between VRRP and BFD

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
The view of the interface on the master where a VRRP group is configured is displayed.
(Optional) On an Ethernet interface, run undo portswitch
The interface is switched to Layer 3 mode.

By default, an Ethernet interface works in Layer 2 mode.

Only the S5720-EI, S5720-HI, S5730-HI, S5731-H, S5731-S, S5731S-H, S5731S-S, S5732-H, S6720-EI, S6720-HI, S6720S-EI, S6730-H, S6730S-H, S6730-S, and S6730S-S support switching between Layer 2 and Layer 3 modes.
Run vrrp vrid virtual-router-id track bfd-session { bfd-session-id | session-name bfd-configure-name } [ increased value-increased | reduced value-reduced ]
Association between VRRP and BFD is configured.

By default, when the monitored BFD session goes Down, the VRRP priority decreases by 10.
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.
- After a VRRP group is associated with a BFD session, the BFD session type cannot be modified. Before deleting the BFD session type, you must delete all original configurations.
- After the value by which the priority decreases is set, ensure that the priority of the backup is higher than the priority of the master.