D-Link DGS-6600-48T Product Manual - Page 406

DGS-6604 m loopback-detection (global) loopback-detection (global) Use the command to enable global loopback detection function. Use no form to disable the function. loopback-detection no loopback-detection Syntax None Default Disabled Command Mode Usage Guideline Configuration mode Used to enable or disable the LBD function globally. When a port enables the loopback-detection function, and switch is in forwarding state, will periodically sends out CTP packets with the SA field set to device's MAC, DA field set to CF-00-00-00-00-00. Type is "90-00". If the port is an untagged member of a VLAN, this port will send out the untagged CTP packet. If the port is only tagged member of VLAN, then this port will send out the tagged packet with one of the VLAN ID to which this port belonged. Example When the switch detects that a CTP packet sent out by the port has been looped back to the packet originating port, it will put this port into error disabled state or block the traffic which belong to this VLAN according to the detection mode user configured. There are two kinds of recovery mechanisms provide, user can bring it out of this state by entering the "errdisable recovery cause loopback-detection" global configuration command. Alternatively, the user can manually re-enable the port by entering the "shutdown" then "no shutdown" command in interfaceconfiguration mode. This example shows how to enable loopback detection function. Switch(config)# loopback-detection Switch(config)# You can verify your settings by entering the show loopback-detection command. CLI Reference Guide 396