H3C Technologies H3C S3600 Series Switches - Manual (Page 247)

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2 stays standby. When VLAN-interface 1 or the link connected to VLAN-interface 1 fails and thus cannot
transmit traffic normally, VLAN-interface 2 takes over to transmit traffic. In this way, the traffic can be
transmitted smoothly without interruption.
Figure 1-2 Schematic diagram for VLAN interface backup
Using Auto Detect can help implement VLAN interfaces backup. When data can be transmitted through
two VLAN interfaces on the switch to the same destination, configure one of the VLAN interface as the
active interface and the other as the standby interface. The standby interface is enabled automatically
when the active fails, so as to ensure the data transmission. In this case, the Auto Detect function is
implemented as follows:
z In normal situations (that is, when the detected group is reachable), the standby VLAN interface is
down and packets are transmitted through the active VLAN interface.
z When the link between the active VLAN interface and the destination faults (that is, the detected
group is unreachable), the system enables the backup VLAN interface.
z When the link between the active VLAN interface and the destination recovers (that is, the detected
group becomes reachable again), the system shuts down the standby VLAN interface again.
You need to create the detected group and perform configurations concerning VLAN interfaces before
the following operations.
Follow these steps to configure the auto detect function for VLAN interface backup:
To do… Use the command… Remarks
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.