Port shutdown with broadcast storm

A LAN broadcast storm arises when an excessively high rate of broadcast packets flood the LAN. Occurrence of LAN broadcast storm disrupts traffic and degrades network performance. To prevent LAN traffic from being disrupted, an enhancement of fault-finder commands adds new options, and the corresponding MIBs, that trigger a port disablement when a broadcast storm is detected on that port.

Under this enhancement, the CLI commands given only supports broadcast traffic and not multicast and unicast types of traffic.

The waiting period range for re-enabling ports is 0 to 604800 seconds. The default waiting period to re-enable a port is zero which prevents the port from automatic re-enabling.


Avoid port flapping when choosing the waiting period by considering the time to re-enable carefully.

Use the following commands to configure the broadcast-storm on a port.


no fault-finder broadcast-storm [ethernet] <port-list> action [warn|warn-and-disable <seconds>] [percent <percent>|pps <rate>]

To remove the current configuration of broadcast-storm on a port, use:


no fault-finder broadcast-storm [ethernet] <port-list>

Configure broadcast storm control.


Rising threshold level in number of broadcast packets per second.


Rising threshold level as a percentage of bandwidth of the port. The percentage is calculated on 64 byte packet size.


Log the event only.


Log the event and disable the port.


Re-enable the port after waiting for the specified number of seconds. Default is not to re-enable.

Configuration examples:

switch(config)# fault-finder broadcast-storm [ethernet] <A1> action [warn-and-disable <65535>]< percent 10>
switch(config)# fault-finder broadcast-storm [ethernet] <A2> action [warn-and-disable <pps 100>
switch(config)# fault-finder broadcast-storm [ethernet] <A22> action [warn] <pps 100>