Allied Telesis AlliedWare Plus Operating System Version 5.4.4C (x310-26FT,x310-26FP,x310-50FT,x310-50FP) - Manual (Page 356)

Switching Introduction
Software Reference for x310 Series Switches
14.14 AlliedWare Plus TM Operating System - Version 5.4.4C C613-50046-01 REV A
Configuration
To enable loop protection and configure its basic parameters, you use the loop-
protection command on page 15.14 .
Example To enable the loop-detect mechanism, and generate loop-detect frames once every 5
seconds, use the command:
You can now use the loop-protection action command on page 15.15 configure the
action that the switch will take if a loop is detected.
Example To disable an interface, and bring the link down, when a network loop is detected, use the
command:
Now decide how long you want the protective action to apply for. You configure this
function by using the
loop-protection timeout command on page 15.16 .
Example To configure a loop protection action timeout of 10 seconds, use the command:
Thrash Limiting
MAC address thrashing occurs when MAC addresses move rapidly between one or more
ports or trunks, for example, due to a network loop.
Thrash limiting enables you to apply actions to a port when thrashing is detected. It is
supported on all port types and also on aggregated ports.
Limiting Actions There are several different thrash actions that you can apply to a port when thrashing is
detected. These actions are:
■ learnDisable
MAC address learning is temporarily disabled on the port.
■ portDisable
The port is logically disabled. Traffic flow is prevented, but the link remains up. The
device at the other end does not notice that the port has changed status, and the link
LEDs at both ends stay on.
■ linkDown
The port is physically disabled and the link is down. This is equivalent to entering the
shutdown command on page 12.14 .
■ vlanDisable
The port is disabled only for the VLAN on which thrashing has occurred. It can still
receive and transmit traffic for any other VLANs of which it is a member.
awplus(config)# loop-protection loop-detect ldf-interval 5
Note LDFs are sent sequentially for each VLAN defined to a particular port. For
example, if a particular port in this example is a member of 4 VLANs, then the
LDFs will be sent from this port at the rate of 4 frames every 5 seconds.
awplus(config-if)# loop-protection action link-down
awplus(config-if)# loop-protection timeout 10