Users Guide

CONFIGURATION mode
storm-control multicast packets_per_second in
• Configure the packets per second of unknown-unicast traffic allowed in or out of the network.
CONFIGURATION mode
storm-control unknown-unicast packets_per_second in
Detect PFC Storm
The following section explains the procedure to detect the PFC storm.
You can detect the PFC storm by polling the lossless queues in a port or priority periodically. When the queue
depth is not equal to zero or when the queue has traffic after subsequent number of polling, then the port or
priority is detected to have the PFC storm.
• Use the polling—interval {interval in milli-seconds} command to set the polling interval.
The queue traffic and egress counters are polled.
• Use the xoff-state threshold polling-count {number of polling-interval} command
to set the number of times the polling should be done. If the traffic and the egress counter remain the
same after the subsequent polling, then the corresponding port or priority is detected to have PFC
storm.
• Once PFC storm is detected on an interface, you can use the storm-control pfc in queue-drop
command on the interface to drop the ingress packets. This command triggers a queue drop state on
the interface with PFC storm, so that the traffic through other ports and priorities are not affected.
For more information about the above commands, see the Dell Networking OS Command Line Reference
Guide.
Restore Queue Drop State
You can restore the queue drop triggered due to the storm control PFC detection to the normal state.
Once the storm control PFC is detected on a port or priority, you can activate the queue drop action. You can
restore the dropped queue to normal state on the following conditions.
• You can restore the queue after a particular period of time. Use the queue-drop backoff-force
polling—count command to remove the queue-drop state after the specified number of polling is
done. The queue-drop state, which has been activated due to the detection of storm control PFC, is
forced to get removed. When the
number of polling-interval is set as ‘zero’, the queue-drop state is not
removed until it is explicitly cleared using the storm-control pfc in queue-drop-state clear
command.
• You can restore the queue when additional PFC packets for a particular priority are not received for a
specified period of time. Use the queue-drop backoff-on-norxpfc polling-count command to
remove the queue-drop state if additional PFCs are not received after the specified number of polling is
done.
For more information about the above commands, see the Dell Networking OS Command Line Reference
Guide.
Storm Control 965