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Configuring VRRP
657
The priority ranges from 0 to 255. The greater the number, the higher the priority. 
However the value can only be taken from 1 to 254. The priority 0 is reserved for 
special use and 255 is reserved for the IP address owner by the system.
By default, the priority is 100.
The priority for IP address owner is always 255, which cannot be configured 
otherwise.
Configuring Preemption 
and Delay for a Switch 
within a Virtual Router
Once a switch in the virtual router becomes the Master switch, so long as it still 
functions properly, other switches, even configured with a higher priority later, 
cannot become the Master switch unless they are configured to work in 
preemption mode. The switch in preemption mode will become the Master 
switch, when it finds its own priority is higher than that of the current Master 
switch. Accordingly, the former Master switch will become the Backup switch.
Together with preemption settings, a delay can also be set. In this way, a Backup 
will wait for a period of time before becoming a Master. In an unstable network if 
the Backup switch has not received the packets from the Master switch punctually, 
it will become the Master switch. However, the failure of Backup to receive the 
packets may be due to network congestion, instead of the malfunction of the 
Master switch. In this case, the Backup will receive the packet after a while. The 
delay settings can thereby avoid the frequent status changing.
Perform the following configuration in VLAN interface view.
The delay ranges from 0 to 255, measured in seconds. By default, the preemption 
mode is preemption with a delay of 0 second.
If preemption mode is cancelled, the delay time will automatically become 0 
second.
Configuring 
Authentication Type and 
Authentication Key
VRRP provides following authentication types:
simple: Simple character authentication
md5: MD5 authentication
Table 596   Configure the priority of switches in the virtual router.
Operation 
Command 
Configure the priority of switches in the 
virtual router. 
vrrp vrid virtual-router-ID priority priority 
Clear the priority of switches in the virtual 
router. 
undo vrrp vrid virtual-router-ID priority
Table 597   Configure preemption and delay for a switch within a virtual router
Operation 
Command 
Enable the preemption mode and configure a 
period of delay. 
vrrp vrid virtual-router-ID preempt-mode [ 
timer delay delay-value ] 
Disable the preemption mode. 
undo vrrp vrid virtual-router-ID 
preempt-mode