3com 5500-SI Manual Do Utilizador

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ONFIGURATION

c Set the backup group preference value of Switch D to 100.

[S5500 D-vlan-interface1] vrrp vrid 1 priority 100

The interface backup function is used to back up VLAN interfaces by using the auto 
detect function. For two VLAN interfaces configured with the same destination 
device, you can configure them to be the primary interface and the secondary 
interface. The latter is enabled automatically when the primary fails, so as to ensure 
the connectivity. In this case, the auto detect function is implemented as follows:

■

In normal situations (that is, the result of the detecting group is reachable), the 
secondary VLAN interface is down and packets are transmitted through the 
primary VLAN interface.

■

When the link between the primary VLAN interface and the destination operates 
improperly (that is, the result of the detecting group is unreachable), the system 
shuts down the primary VLAN interface and enables the secondary VLAN 
interface.

■

When the link between the primary VLAN interface and the destination comes 
back up (that is, the result of the detecting group becomes reachable again), the 
system enables the primary VLAN interface and shuts down the secondary.

You need to create a detecting group and perform configurations concerning VLAN 
interfaces before the following operations.

■

Configure a static route between Switch B and Switch C.

■

Create detecting group 10 on Switch A, which is used to detect the connectivity 
between Switch B and Switch C.

■

Configure VLAN 1 interface to be the primary interface, which operates when the 
result of detecting group 10 is reachable.

■

Configure VLAN 2 interface to be the secondary interface, which operates when 
the result of the detecting group is unreachable.

■

Make sure the dynamic routes between Switch A, Switch B, and Switch C are 
reachable; and those between Switch A, Switch D, and Switch C are also 
reachable.

Table 594   Configure the auto detect function for VLAN interface backup

Enter system view

system-view

-

Enter VLAN interface view

interface vlan-interface 
vlan_id

-

Enable the auto detect 
function to implement 
VLAN interface backup

standby detect-group 
group-number

Required
This operation is only needed on 
the secondary VLAN interface.