Switchport packet-rate – Brocade Communications Systems Brocate Ethernet Access Switch 6910 User Manual

Page 320

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270

Brocade 6910 Ethernet Access Switch Configuration Guide

53-1002581-01

Interface Commands

12

switchport packet-rate

This command configures broadcast, multicast and unknown unicast storm control. Use the no
form to restore the default setting.

Syntax

switchport {broadcast | multicast | unicast} packet-rate rate

no switchport {broadcast | multicast | unicast}

broadcast - Specifies storm control for broadcast traffic.

multicast - Specifies storm control for multicast traffic.

unicast - Specifies storm control for unknown unicast traffic.

rate - Threshold level as a rate; i.e., kilobits per second.
(Range: 64-100000 Kbps for Fast Ethernet ports,
64-1000000 Kbps for Gigabit Ethernet ports)

Default Setting

Broadcast Storm Control: Enabled, packet-rate limit: 64 kbps
Multicast Storm Control: Disabled
Unknown Unicast Storm Control: Disabled

Command Mode

Interface Configuration (Ethernet)

Command Usage

When traffic exceeds the threshold specified for broadcast and multicast or unknown unicast
traffic, packets exceeding the threshold are dropped until the rate falls back down beneath the
threshold.

Traffic storms can be controlled at the hardware level using this command or at the software
level using the

auto-traffic-control

command. However, only one of these control types can be

applied to a port. Enabling hardware-level storm control on a port will disable automatic storm
control on that port.

The rate limits set by this command are also used by automatic storm control when the control
response is set to rate limiting by the

auto-traffic-control action

command.

Using both rate limiting and storm control on the same interface may lead to unexpected
results. For example, suppose broadcast storm control is set to 500 Kbps by the command
“switchport broadcast packet-rate 500,” and the rate limit is set to 20000 Kbps by the
command “rate-limit input 20000" on a Fast Ethernet port. Since 20000 Kbps is 1/5 of line
speed (100 Mbps), the received rate will actually be 100 Kbps, or 1/5 of the 500 Kbps limit set
by the storm control command. It is therefore not advisable to use both of these commands on
the same interface.

Example

The following shows how to configure broadcast storm control at 600 kilobits per second:

Console(config)#interface ethernet 1/5

Console(config-if)#switchport broadcast packet-rate 600

Console(config-if)#

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