3com 5500-SI Manual De Usuario

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VRRP Configuration 155
Configuring VRRP timer
The master switch advertises its normal operation state to the switches within the 
VRRP backup group by sending VRRP packets once in each specified interval 
(determined by the adver-interval argument). If the backup switches do not receive 
VRRP packets from the master after a specific period (determined by the 
master-down-interval argument), they consider the master is down and initiates the 
process to determine the master switch.
You can adjust the frequency in which a master sends VRRP packets by setting the 
corresponding VRRP timers (that is, the adver-interval argument). The 
master-down-interval argument is usually three times of the adver-interval argument. 
Excessive network traffic or differences between the timers of different 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 to be tracked for a backup group
The VLAN interface 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 are unavailable. 
By executing the related command you can track an interface.
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.
VRRP Configuration
The following sections describe the VRRP configuration tasks:
Configuring a Virtual
Router IP address
Table 137 lists the operations to configure a virtual router IP address (suppose you 
have correctly configured the relation between the port and VLAN):
Table 137   Configure a virtual router IP address
Operation
Command
Description
Enter system view
system-view
-
Configure that the 
virtual IP address can 
be pinged
Vrrp ping-enable
Optional
By default, the virtual IP address 
cannot be pinged.
Map the virtual router 
IP address to a MAC 
address
Vrrp method real-mac | 
virtual-mac }
Optional
By default, the virtual IP address of a 
backup group is mapped to a virtual 
router IP address.
Create a VLAN
vlan vlan-id
-
Quit to system view
quit
-
Enter VLAN interface 
view
interface vlan-interface vlan-id -