Leaflet

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OL-11615-01
Broadcast suppression is disabled by default. To configure broadcast suppression on the Catalyst 6500
running Catalyst OS, use the set port broadcast command. Enable the broadcast suppression threshold
for one or more ports as a percentage of the total bandwidth:
Console> (enable) set port broadcast mod/port threshold% [violation {drop-packets |
errdisable}] [multicast {enable | disable}][unicast {enable | disable}]
When broadcast, multicast, or unicast suppression occurs, you can configure the ports to either drop the
packets or go into the errdisable state. The errdisable state feature can be enabled or disabled on a
per-port basis, and is disabled by default (the drop-packets option is enabled by default).
When a port is put into errdisable state, it can be re-enabled after a specific timeout interval has expired.
Enter the set errdisable-timeout interval command to specify the timeout interval.
This example shows how to limit the broadcast traffic to 90 percent and error disable the port when
broadcast suppression occurs:
Console> (enable) set port broadcast 4/6 90% violation errdisable
Port 4/6 broadcast traffic limited to 90.00%.
On broadcast suppression port 4/6 is configured to move to errdisabled state.
Console> (enable)
For more information on Broadcast Suppression on the Catalyst 6500 running Catalyst OS, refer to the
following URL:
http://www.cisco.com/univercd/cc/td/doc/product/lan/cat6000/sw_8_5/confg_gd/bcastsup.htm
Catalyst 6500 Traffic Storm Control (Cisco IOS)
The traffic storm control feature on Catalyst 6500 Series switches is supported for both Catalyst OS and
Cisco IOS. In this switching platform, broadcast traffic storm control is supported on all LAN ports,
while multicast and unicast traffic storm control is supported only on Gigabit and 10 Gigabit Ethernet
ports.
Traffic storm control on the Catalyst 6500 Series switches is implemented in hardware. The traffic storm
control circuitry monitors packets passing from a LAN interface to the switching bus. Using the
Individual/Group bit in the packet destination address, the traffic storm control circuitry determines if
the packet is unicast or broadcast, keeps track of the current count of packets within the 1-second
interval, and when a threshold is reached, filters out subsequent packets.
Note The WS-X6548-GE-TX, WS-X6548V-GE-TX, WS-X6148-GE-TX, and WS-X6148V-GE-TX switching
modules do not support traffic storm control.
Because hardware traffic storm control uses a bandwidth-based method to measure traffic, the most
significant implementation factor is setting the percentage of total available bandwidth that can be used
by controlled traffic. Because packets do not arrive at uniform intervals, the 1-second interval during
which controlled traffic activity is measured can affect the behavior of traffic storm control.
Note Multicast suppression does not drop bridge protocol data unit (BPDU) packets unless is enabled in one
of the following modules: WS-X6724-SFP, WS-X6748-GE-TX, WS-X6748-SFP, WS-X6704-10GE,
WS-SUP32-GE-3B, and WS-SUP32-10GE-3B. Enabling multicast suppression on these modules can
cause BPDUs to be suppressed when the multicast suppression threshold is exceeded. We strongly
advise that you do not use multicast suppression on ports that need to receive BPDUs because potential
side effects can be root port loss or spanning tree loops when the suppression threshold is exceeded. As
an alternative, consider using the Layer 2 hardware-based rate limiter present on Supervisor 32 and 720