3Com 8807 Configuration Manual page 657

n
Configuring Preemption
and Delay for a Switch
within a Virtual Router
n
Configuring
Authentication Type and
Authentication Key
Table 596 Configure the priority of switches in the virtual router.
Operation
Configure the priority of switches in the
virtual router.
Clear the priority of switches in the virtual
router.
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.
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.
Table 597 Configure preemption and delay for a switch within a virtual router
Operation
Enable the preemption mode and configure a
period of delay.
Disable the preemption mode.
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.
VRRP provides following authentication types:
simple: Simple character authentication
■
md5: MD5 authentication
■
Configuring VRRP
Command
vrrp vrid virtual-router-ID priority priority
undo vrrp vrid virtual-router-ID priority
Command
vrrp vrid virtual-router-ID preempt-mode [
timer delay delay-value ]
undo vrrp vrid virtual-router-ID
preempt-mode
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