3Com Switch 7750 Configuration Guide Guide

VRRP Configuration 531
switches will result in master-down-interval timing out and state changing
abnormally. Such problems can be solved through prolonging the adver-interval
and setting delay time. If you configure the preemption delay for a backup switch,
the switch preempts the master after the period specified by the preemption delay
if it does not receive a VRRP packet from the master for the period specified by the
master-down-interval argument.
Configuring the VLAN interfaces/Ethernet ports to be tracked for a backup
group
The VLAN interface/Ethernet port tracking function expands the backup group
function. With this function enabled, the backup group function is provided not
only when the interface where the backup group resides fails, but also when other
interfaces/Ethernet ports are unavailable. By executing the related command you
can track an interface/Ethernet port.
When a tracked VLAN interface goes down, the priority of the switch owning the
interface will reduce automatically by a specified value (the value-reduced
argument). If the switches with their priorities higher than that of the current
master switch exist in the backup group, a new master switch will be then
determined.
Similarly, when the tracked Ethernet port is down, the priority of its switch will be
degraded by value-reduced automatically. As a result, other switch in the backup
group may have a higher priority than this switch and therefore take over the role
as a master switch.
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■ The Ethernet port tracked can be in or out of the VLAN in whose interface the
backup group resides.
■ If a switch is the IP address owner, the VLAN interface/Ethernet port tracking
function can not be enabled for the switch.
■ If a tracked VLAN interface/Ethernet port goes down, when it is up again, the
priority of the corresponding switch is automatically restored.
■ Each backup group can track up to eight VLAN interfaces/Ethernet ports.
VRRP Configuration
Introduction to VRRP
Configuration Tasks
Configuring a Virtual
Router IP address
Table 405 lists the operations to configure a virtual router IP address (suppose you
have correctly configured the mapping between the port and VLAN):
Table 404 VRRP configuration tasks
Configuration Description Related section
Configure a virtual router IP
address
Required
“Configuring a Virtual Router
IP address”
Configure backup
group-related parameters
Required
“Configuring Backup
Group-Related Parameters”