Configuring Flooding Controls; Enabling Storm Control - Cisco WS-C2950-24 Configuration Manual

Configuring Flooding Controls

Configuring Flooding Controls

Enabling Storm Control

Catalyst 2900 Series XL and Catalyst 3500 Series XL Software Configuration Guide
7-4
You can use the following flooding techniques to block the forwarding of
unnecessary flooded traffic:
Enable storm control for unicast, multicast, or broadcast packets
•
• Block the forwarding of unicast and broadcast packets on a per-port basis
Flood all unknown packets to a network port (configured only by using CLI)
•
A packet storm occurs when a large number of broadcast, unicast, or multicast
packets are received on a port. Forwarding these packets can cause the network to
slow down or to time out. Storm control is configured for the switch as a whole
but operates on a per-port basis. By default, storm control is disabled.
Storm control uses high and low thresholds to block and then restore the
forwarding of broadcast, unicast, or multicast packets. You can also set the switch
to shut down the port when the rising threshold is reached.
The rising threshold is the number of packets that a switch port can receive before
forwarding is blocked. The falling threshold is the number of packets below
which the switch resumes normal forwarding. In general, the higher the threshold,
the less effective the protection against broadcast storms. The maximum
half-duplex transmission on a 100BASE-T link is 148,000 packets per second, but
you can enter a threshold of up to 4294967295 broadcast packets per second.
Chapter 7 Configuring the Switch Ports
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