H3C SecPath F5020, Interface Configuration Manual

17 

Step Command 

Remarks 

5.

Enable unknown unicast 
suppression and set the 

unknown unicast suppression 
threshold. 

unicast-suppression

 { 

ratio 

|

pps

max-pps

 | 

kbps 

max-kbps

 }

By default, unknown unicast 
suppression is disabled.  

Configuring storm control on an Ethernet interface 

About storm control 

Storm control compares broadcast, multicast, and unknown unicast traffic regularly with their respective 
traffic thresholds on an Ethernet interface. For each type of traffic, storm control provides a lower 

threshold and an upper threshold.  
Depending on your configuration, when a particular type of traffic exceeds its upper threshold, the 

interface performs either of the following tasks:  

•

Blocks this type of traffic and forwards other types of traffic

—Even though the interface does not 

forward the blocked traffic, it still counts the traffic. When the blocked traffic drops below the lower 

threshold, the interface begins to forward the traffic.  

•

Goes down automatically

—The interface goes down automatically and stops forwarding any 

traffic. When the blocked traffic drops below the lower threshold, the interface does not 

automatically come up. To bring up the interface, use the 

undo shutdown

 command or disable the 

storm control function. 

You can configure an Ethernet interface to output threshold event traps and log messages when 

monitored traffic meets one of the following conditions: 

•

Exceeds the upper threshold.  

•

Drops below the lower threshold. 

Any of the 

storm-constrain

, 

broadcast-suppression

, 

multicast-suppression

, and 

unicast-suppression

commands can suppress storm on an interface. The 

broadcast-suppression

, 

multicast-suppression

, and 

unicast-suppression

 commands suppress traffic in hardware. They have less impact on the device 

performance than the 

storm-constrain

 command, which suppressions traffic in software.  

Storm control uses a complete polling cycle to collect traffic data, and analyzes the data in the next cycle. 

An interface takes one to two polling intervals to take a storm control action. 

Configuration restrictions and guidelines 

For the same type of traffic, do not configure storm control together with storm suppression. Otherwise, 
the traffic suppression result is not determined. For more information about storm suppression, see 

"

Configuring storm suppression

."  

Configuration procedure 

To configure storm control on an Ethernet interface: 

Step Command 

Remarks 

1.

Enter system view. 

system-view 

N/A