3com 3.01.01 用户手册

The delay ranges from 0 to 255, measured in seconds. The default mode is 
preemption with a delay of 0 second.

To prevent unauthorized routes from joining the virtual router, a key can be 
configured that is used in one of the following VRRP authentication types: 

■

Simple character authentication — The authentication type is set to simple. 
The switch adds the authentication key to the VRRP packets before 
transmitting it. The receiver compares the authentication key of the packet to 
the locally configured authentication key. If they are the same, the packet is 
accepted as a true and legal. If the keys are not the same the packet is 
considered illegal and is discarded. A simple authentication key should not 
exceed 8 characters.

■

MD5 authentication — The authentication type is set to md5. The switch uses 
the authentication type and MD5 algorithm, provided by the authentication, 
header to authenticate VRRP packets. An md5 authentication key should not 
exceed 16 packets that fail to pass the authentication test. If 16 fail they are 
discarded and a trap packet is sent to the network management system.

Perform the following configuration in VLAN interface view.

The Master switch advertises its normal operation state to the switches within the 
VRRP virtual router by sending them VRRP packets regularly, at the specified 
advertised interval. If the backup switch does not receive a VRRP packet from the 
master after a period of time (specified by master-down-interval), the master is 
assumed to have failed and the backup switch takes the role of master.

You can use the following command to set a timer and adjust the interval, 
adver-interval at which the master transmits VRRP packets. The duration of the 
backup switch’s master-down-interval is three times the duration of the 
adver-interval. Excessive network traffic or the differences between different 
switch timers results in master-down-interval timing out and state changing 
abnormally. Such problems can be solved through prolonging the adver-interval 
and setting delay time. The duration of adver-interval is measured in seconds.

Perform the following configuration in VLAN interface view.

Table 6   Configure Authentication Type and Authentication Key

Configure the authentication type and 
authentication key.

vrrp authentication-mode type [ key ]

Clear the authentication type and 
authentication key.

Table 7   Configure VRRP Timer

Configure VRRP timer

vrrp vrid virtual-router-ID timer advertise 
adver-interval