JetStream  52-Port Gigabit Stackable L3 Managed Switch  CLI Guide 
 
Chapter 28  Loopback Detection Commands 
With loopback detection feature enabled, the switch can detect loops using loopback 
detection packets. When a loop is detected, the switch will display an alert or further block the 
corresponding port according to the configuration. 
28.1  loopback-detection(global) 
Description 
The loopback-detection command is used to enable the loopback detection 
function globally. To disable it, please use no loopback detection command. 
Syntax 
loopback-detection   
no loopback-detection 
Command Mode 
Global Configuration Mode 
Example 
Enable the loopback detection function globally: 
T3700G-52TQ(config)# loopback-detection 
28.2  loopback-detection interval 
Description 
The loopback-detection interval command is used to define the interval of 
sending loopback detection packets from switch ports to network, aiming at 
detecting network loops periodically. 
Syntax 
loopback-detection interval 
interval-time
 
Parameter 
interval-time 
āā  The interval of sending loopback detection packets. It 
ranges from 1 to 1000 seconds. By default, this value is 30 seconds. 
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