The vrrp smooth-switching timer command enables VRRP smooth switching and sets the interval contained in VRRP Advertisement packets during VRRP smooth switching.
The undo vrrp smooth-switching timer command disables VRRP smooth switching.
By default, VRRP smooth switching is enabled and the interval contained in VRRP Advertisement packets is 100s.
| Parameter | Description | Value |
|---|---|---|
| timer-value | Specifies the interval contained in VRRP Advertisement packets during VRRP smooth switching. After VRRP smooth switching is enabled on the master, the master sends VRRP Advertisement packets at this interval during an active/standby switchover. |
The value is an integer that ranges from 1 to 255, in seconds. |
Usage Scenario
If an active/standby switchover occurs on the master in the stack system in a VRRP group, the master and backup may fail to communicate with each other during the switchover. During the switchover, the backup with the highest priority becomes the new master if backups receive no VRRP Advertisement packet after the VRRP Advertisement packet sending interval expires. In this situation, two masters coexist. After the active/standby switchover is complete on the original master, the original master switches to the master because its priority is higher than the new master. During this process, services are switched twice, causing unstable service transmission.
After VRRP smooth switching is enabled on the device in the stack system, backups learn the smooth switching time. This implementation extends the timeout interval for receiving VRRP Advertisement packets during VRRP smooth switching, ensuring stability of the VRRP group status.
Prerequisites
The device has been enabled to learn the interval for sending VRRP Advertisement packets using the vrrp timer-advertise learning enable command.
Precautions
After receiving VRRP Advertisement packets from the master, the non-master device checks the interval in VRRP Advertisement packets. If the interval in VRRP Advertisement packets is different from the interval of the non-master device, the non-master device learns the interval and adjusts its own interval to be the same as the learned interval.
timer-value must be greater than the interval at which VRRP Advertisement packets are sent. Otherwise, the master may be busy during the switchover and unable to send VRRP Advertisement packets in a timely manner. As a result, a backup switches to the master.
After the undo vrrp timer-advertise learning enable command is executed, VRRP smooth switching is also disabled.