Specifications

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Cisco MWR 2941 Mobile Wireless Edge Router Release 3.5 Software Configuration Guide, Cisco IOS Release 15.1(3)MR
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Chapter 28 Configuring Traffic Storm Control
Guidelines and Limitations
• If you enable unicast traffic storm control, and unicast traffic exceeds the level within a 1-second
traffic storm control interval, traffic storm control drops all traffic (broadcast, multicast, and unicast)
on the interface until the end of the traffic storm control interval.
• If you enable broadcast and multicast traffic storm control, and broadcast traffic exceeds the level
within a 1-second traffic storm control interval, traffic storm control drops all broadcast traffic on
the interface until the end of the traffic storm control interval.
• If you enable broadcast and multicast traffic storm control, and multicast traffic exceeds the level
within a 1-second traffic storm control interval, traffic storm control drops all traffic (broadcast,
multicast, and unicast) on the interface until the end of the traffic storm control interval.
Note By default, traffic storm control is disabled.
Additionally, the Cisco MWR 2941 supports error disable recovery in traffic storm control for interfaces
on which storm control action shutdown is configured.
A port is in the error-disabled (err-disabled) state when the port is enabled administratively (using the
no shutdown command) but disabled at runtime by any process such as traffic storm control.
Because the port is administratively enabled, the port status displays as err-disable when shut down by
the traffic storm control process. Once a port goes into the err-disable state, you must manually re enable
it or you can configure a timeout value that provides an automatic recovery. By default, the automatic
recovery is not configured, and by default the err-disable detection is enabled for all causes.
You can configure the automatic error-disabled recovery timeout for a particular error-disabled cause
and configure the recovery period.
Guidelines and Limitations
When configuring traffic storm control, note the following:
• The Cisco MWR 2941 does not support storm control on a port-channel interface.
• Storm control on the Cisco MWR 2941 does not control protocol data units (PDUs).
When the storm control threshold for multicast traffic is reached, all multicast traffic except control
traffic, such as bridge protocol data units (BDPUs) and Cisco Discovery Protocol (CDP) frames, are
blocked. However, the Cisco MWR 2941 does not differentiate between routing updates, such as
OSPF, and regular multicast data traffic, so both types of traffic are blocked.
• In the show interface counters command output, multicast packets are counted as unicast packets.
• The following SNMP trap message applies to all traffic (broadcast, multicast, and unicast) storm
detection:
%MWR2900_STORM_CONTROL-2-TRAP: Storm control Sending SNMP trap
GigabitEthernet{slot/port}.
• The Cisco MWR 2941 does not support the debugging of traffic storm control.