Cisco Systems A9014CFD manual Configuring Storm Control, 38-2

Chapter 38 Storm Control

Feature Overview

Prerequisites

•Cisco IOS Release 15.3(3)S or a later release that supports the Storm Control feature must be installed previously on the Cisco ASR 901 Series Aggregation Services Router.

Restrictions

•The storm-controlcommand is not recommended on an interface that is part of a port channel.

•Storm-control counters are not supported on port channel as the counters are based on physical ports.

•Discarded counters are not displayed for port channel. You should check the port channel member-ports for discarded counters.

•The current rate field is not supported for show commands in hardware based storm control.

•Supports only drop counters. Total broadcast received in storm control is not supported.

Feature Overview

A traffic storm occurs when huge amount of broadcast, multicast, or unknown unicast packets flood the LAN, creating excessive traffic and degrading network performance. Errors in the protocol-stack implementation or in the network configuration can also cause a storm. The mechanism to prevent and control such events is known as storm control or broadcast suppression.

The Storm Control feature prevents switchports on a LAN from being disrupted by a broadcast, multicast, or unknown unicast storm on one of the interfaces. This feature monitors incoming traffic statistics over a time period and compares the measurement with a predefined suppression level threshold. The threshold represents the percentage of the total available bandwidth of the port. If the threshold of a traffic type is reached, the system takes the appropriate storm control action until the incoming traffic falls below the threshold level.

Storm control also acts as a policer, and it drops only the storms that breaches the configured storm level.

This feature supports the following:

•Ethernet port: per port configuration for broadcast, multicast, and unknown unicast traffic.

•10 GigabitEthernet interfaces.

•SNMP trap and SYSLOG messages: indicating storm control detection.

•Individual dropped packet counters: for broadcast, multicast, and unknown unicast flows.

•Error disable recovery feature with storm control shutdown action.

Configuring Storm Control

To configure Storm Control feature, complete the following steps:

Note This feature is disabled by default.

	Cisco ASR 901 Series Aggregation Services Router Software Configuration Guide
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