PLANET WGSW-52040 - Manual (Page 96)

As shown in the above configuration, the switch will detect the existence of loopbacks in the
network topology. After enabling the function of loopback detection on the port connecting the
switch with the outside network, the switch will notify the connected network about the
existence of a loopback, and control the port on the switch to guarantee the normal operation
of the whole network.
The configuration task sequence of SWITCH:
Switch(config)#loopback-detection interval-time 35 15
Switch(config)#interface ethernet 1/1
Switch(Config-If-Ethernet1/1)#loopback-detection special-vlan 1-3
Switch(Config-If-Ethernet1/1)#loopback-detection control block
If adopting the control method of block, MSTP should be globally enabled. And the
corresponding relation between the spanning tree instance and the VLAN should be
configured.
Switch(config)#spanning-tree
Switch(config)#spanning-tree mst configuration
Switch(Config-Mstp-Region)#instance 1 vlan 1
Switch(Config-Mstp-Region)#instance 2 vlan 2
Switch(Config-Mstp-Region)#
9.4 Port Loopback Detection Troubleshooting
The function of port loopback detection is disabled by default and should only be enabled if
required.
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