Operation Manual

34
Storm Control
The Storm Control feature provides the ability to control
the receive rate of broadcast, multicast, and unknown
unicast packets. Storm Control prevents trafc on a LAN
from being disrupted by a broadcast, multicast, or unicast
stormonaport.ALANstormoccurswhenpacketsood
theLAN,creatingexcessivetrafcanddegradingnetwork
performance. Errors in the protocol-stack implementation,
mistakes in network conguration, or users issuing a
denial-of-service attack can cause a storm. Storm control
uses rising and falling thresholds to block and then restore
the forwarding of broadcast, unicast, or multicast packets.
Click the Storm ControllinkundertheQoSmenutolimit
excessiveoodingcausedbyapacketstorm.
Port: Selecttypeoftrafcwillbelimited.
• Unknown Unicast: If the rate of unknown L2 unicast (destination
 lookupfailure)trafcingressingonaninterfaceincreasesbeyondthe
 conguredthreshold,thetrafcwillbedropped.
• Multicast:IftherateofL2multicasttrafcingressingonaninterface
 increasesbeyondtheconguredthreshold,thetrafcwillbe
dropped.
• Broadcast:IftherateofL2broadcasttrafcingressingonan
 interfaceincreasesbeyondtheconguredthreshold,thetrafcwill
be dropped.
Threshold: Specify how many packets per second are
allowed to go forwarded: Low = 100 packets per second,
Medium = 500 packets per second, High =1000 packets
per second.