The hrp preempt command enables the preemption function of a VGMP management group and set preempt delay of a VGMP management group.
The undo hrp preempt command disables the preemption function of a VGMP management group.
| Parameter | Description | Value |
|---|---|---|
| interval | Specifies the preempt delay of a VGMP management group. | The value is an integer ranging from 0 to 1800, in seconds. By default, the preempt delay of the VGMP management group is 60s. |
By default, the preempt function of a VGMP management group is enabled and the preempt delay of the VGMP management group is 60s.
Usage Scenario
In active/standby networking, if the active FW fails, the standby FW takes over the services. To configure the active FW to automatically take over the services after it recovers, enable the preempt function for the VGMP management group on the active FW.
In load-balancing networking, two FWs process services. If one FW fails, the other FW takes over the services immediately. Generally, the FW that recovers is expected to take over services so that the two FWs work in load-balancing mode. To achieve this result, enable the preempt function for the VGMP management group on the two FWs in load-balancing mode.
Configuration Impact
If the preempt delay is set to 0, the FW immediately takes over the active role after it recovers. If the preempt delay is set to a non-zero value, the FW takes over the active role in a specified period after it recovers. Generally, set the preempt delay to a proper non-zero value so that route convergence and active/standby FW entry backup are complete before the preempt delay expires.
When service traffic is heavy (for example, a large number of IPSec SAs exist) and the route convergence time is long, it is advised to set the preempt delay to a large value or disable the preempt function to prevent services from being affected by the preempt function or an improper preempt delay.
In active/standby networking, the standby FW does not preempt after it recovers. That is, the preempt function is invalid for the standby FW. Configure the preempt function on the active FW.
Precaution
Setting the preempt delay to 0 or a small value is not recommended as service exceptions may occur.
In hot standby mode, if VRRP and dynamic routing protocols run on the FWs and their upstream and downstream devices, ensure that the preemption delay for the VGMP groups is longer than the convergence period of the dynamic routing protocols (such as OSPF) to prevent service interruptions. Or you can disable the preemption function.
If a hardware fault occurs on the board, the device automatically delivers the undo hrp preempt command during its second reset to prevent repeated active/standby switchovers caused by subsequent reset operations.
In the mirroring mode, the preemption function does not take effect.