A traffic storm occurs when packets flood a VPLS bridge, creating excessive traffic and degrading network performance. Traffic
storm control prevents VPLS bridge disruption by suppressing traffic when the number of packets reaches configured threshold
levels. You can configure separate threshold levels for different types of traffic on each port under a VPLS bridge.
Traffic storm control monitors incoming traffic levels on a port and drops traffic when the number of packets reaches the
configured threshold level during any 1-second interval. The 1-second interval is set in the hardware and is not configurable.
The number of packets allowed to pass during the 1-second interval is configurable, per port, per traffic type. During this
interval, it compares the traffic level with the traffic storm control level that the customer configures.
When the incoming traffic reaches the traffic storm control level configured on the bridge port, traffic storm control drops
traffic until the end of storm control interval.
Traffic storm control level can be configured separately for these traffic types:
Unknown Unicast Traffic
The thresholds are configured using a packet-per-second (pps) and kilobit-per-second (kbps) rate. When the number of packets of the specified traffic type reaches the threshold level on a port, the port drops any
additional packets of that traffic type for the remainder of the 1-second interval. At the beginning of a new 1-second interval,
traffic of the specified type is allowed to pass on the port.
Traffic storm control has little impact on router performance. Packets passing through ports are counted regardless of whether
the feature is enabled. Additional counting occurs only for the drop counters, which monitor dropped packets.
No alarms are produced when packets are dropped.
Bridge Protocol Data Unit (BPDU) packets are not filtered through the storm control feature.
Tunneled BPDU packets are filtered as they are forwarded into bridge.
Traffic storm control is applied to only forwarded packets in the system.