5.2.a Implement and troubleshoot switch security features

5.2.a [ii] Stormcontrol

A traffic storm occurs when packets flood the LAN, creating excessive traffic and degrading network performance. The traffic storm control feature prevents LAN ports from being disrupted by a broadcast, multicast, or unicast traffic storm on physical interfaces. Traffic storm control (also called traffic suppression) monitors incoming traffic levels over a 1-second traffic storm control interval , and during the interval it compares the traffic level with the traffic storm control level that you configure. The traffic storm control level is a percentage of the total available bandwidth of the port. Each port has a single traffic storm control level that is used for all types of traffic (broadcast, multicast, and unicast).

Traffic storm control monitors the level of each traffic type for which you enable traffic storm control in 1-second traffic storm control intervals.

Adam, Paul (2014-07-12). All-in-One CCIE V5 Written Exam Guide (Kindle Locations 5188-5193).  . Kindle Edition.

http://www.cisco.com/en/US/docs/switches/lan/catalyst6500/ios/12.2SX/configuration/guide/storm.html