D-Link DGS-6600-48T Product Manual - Page 404

DGS-6604 m loopback-detection (interface) loopback-detection (interface) Use the command to enable interface loopback detection function. Use the no form to disable the function. loopback-detection no loopback-detection Syntax None Default Disabled Command Mode Usage Guideline Interface mode The command is available for port and port channel interface configuration. 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. 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. The LBD will work only when both the global setting and port setting are enabled. Prompt Message Prompt message at screen Description Cannot enable LBD on the port as it STP and LBD should be mutual exclusive on the same port. is STP enabled. Example This example shows how to enable loopback detection function on port3.1 Switch(config)# interface eth3.1 Switch(config-if)# loopback-detection Switch(config-if)# CLI Reference Guide 394