(Optional) Setting GARP Timers

Context

When a GARP participant is enabled, the LeaveAll timer starts. When the LeaveAll timer expires, the GARP participant sends LeaveAll messages to request that other GARP participants re-register all of their attributes. The LeaveAll timer then restarts.

Devices on a network may have different LeaveAll timer settings. In this case, all the devices use the smallest LeaveAll timer value on the network. When the LeaveAll timer of a device expires, the device sends LeaveAll messages to other devices. After other devices receive the LeaveAll messages, they reset their LeaveAll timers. Therefore, only the LeaveAll timer with the smallest value takes effect, even if devices have different LeaveAll timer settings.

When using the garp timer command to set GARP timers, pay attention to the following points:

The undo garp timer command restores the default values of GARP timers. If the default value of a timer is out of the valid range, the undo garp timer command does not take effect.
The value range of each timer changes along with the values of the other timers. If a value you set for a timer is not in the allowed range, you can change the value of the timer that determines the value range of this timer.
To restore the default values of all the GARP timers, restore the Hold timer to the default value, and then sequentially restore the Join timer, Leave timer, and LeaveAll timer to the default values.

When many dynamic VLANs need to be registered or the network radius is large, using default values of timers may cause VLAN flapping and high CPU usage. In this case, increase values of the timers. The following values are recommended depending on the number of VLANs.

**Table 1** Relationship between GARP timer values and number of dynamic VLANs that need to be registered
Timer	Number of Dynamic VLANs to Be Registered (N)
Timer	N <= 500	500 < N <= 1000	1000 < N <= 1500	N > 1500
GARP Hold timer	100 centiseconds (1 second)	200 centiseconds (2 seconds)	800 centiseconds (8 seconds)	1000 centiseconds (10 seconds)
GARP Join timer	600 centiseconds (6 seconds)	1200 centiseconds (12 seconds)	4000 centiseconds (40 seconds)	6000 centiseconds (1 minute)
GARP Leave timer	3000 centiseconds (30 seconds)	6000 centiseconds (1 minute)	20000 centiseconds (3 minutes and 20 seconds)	30000 centiseconds (5 minutes)
GARP LeaveAll timer	12000 centiseconds (2 minutes)	24000 centiseconds (4 minutes)	30000 centiseconds (5 minutes)	32765 centiseconds (5 minutes and 27.65 seconds)

Procedure

Run system-view
The system view is displayed.
Run garp timer leaveall timer-value
The value of the LeaveAll timer is set.

The default value of the LeaveAll timer is 1000 centiseconds (10 seconds).

The Leave timer length on an interface is restricted by the global LeaveAll timer length. When configuring the global LeaveAll timer, ensure that all the interfaces configured with a GARP Leave timer are working properly.
Run interface interface-type interface-number
The interface view is displayed.
Run garp timer { hold | join | leave } timer-value
The value of the Hold timer, Join timer, or Leave timer is set.

By default, the value of the Hold timer is 10 centiseconds, the value of the Join timer is 20 centiseconds, and the value of the Leave timer is 60 centiseconds.