Configuring loop protection

Loop protection provides protection against loops by transmitting loop protocol packets out of ports on which loop protection has been enabled. When the switch sends out a loop protocol packet and then receives the same packet on a port that has a receiver-action of send-disable configured, it shuts down the port from which the packet was sent.


no loop-protect port-list [[receiver-action [[send-disable] | [no-disable]]] | [transmit-interval 1-10] | [disable-timer 0-604800] | [trap loop-detected]] [mode] [[port] | [vlan]] [vlan vid-list]


Configures per-port loop protection on the switch.


receiver-action send-disable | no-disable

Sets the action to be taken when a loop is detected on the specified ports. The port that receives the loop protection packet determines what action is taken. If send-disable is configured, the port that transmitted the packet is disabled. If no-disable is configured, the port is not disabled when a loop is detected.


The port will not transmit loop protection packets unless it is a member of an untagged VLAN. If a port is only a member of tagged VLANs, the loop protection packets are not transmitted.

Default: send-disable

trap loop-detected

Configures loop protection traps for SNMP indicating when a loop has been detected on a port.

disable-timer 0-604800

Configures how long (in seconds) a port is disabled when a loop has been detected. A value of zero disables the auto re-enable function.

Default: Timer is disabled

transmit-interval 1-10

Configures the time in seconds between the transmission of loop protection packets.

Default: 5 seconds

{mode port | vlan}

Configures loop protection in port or VLAN mode.

vlan vid-list

Configures the VLANs on which loop-protect is enabled. Maximum number of loop-protected VLANs is 32.