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Specifying the lag threshold for a lag group – Brocade FastIron Ethernet Switch Platform and Layer 2 Switching Configuration Guide User Manual

Page 143

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To designate the primary port for the static LAG "blue", use the following command.

device(config)# lag blue static

device(config-lag-blue)# primary-port 1/3/2

Syntax: [no] primary-port stack/slot/port

Once a primary port has been configured for a LAG, all configurations that apply to the primary port are
applied to the other ports in the LAG.

NOTE
This configuration is only applicable for configuration of a static or dynamic LAGs.

Specifying the LAG threshold for a LAG group

You can configure the Brocade device to disable all of the ports in a LAG group when the number of
active member ports drops below a specified threshold value. When a LAG is shut down because the
number of ports drops below the configured threshold, the LAG is kept intact and it is re-enabled if
enough ports become active to reach the threshold. For example, if a LAG group has 8 ports, and the
threshold for the LAG group is 5, then the LAG group is disabled if the number of available ports in the
LAG group drops below 5. If the LAG group is disabled, then traffic is forwarded over a different link or
LAG group.

NOTE
This configuration is only applicable for only the configuration of static LAGs.

For example, the following commands establish a LAG group consisting of 4 ports, then establish a
threshold for this LAG group of 3 ports.

device(config)# lag blue static

device(config-lag-blue)# ports ethernet 1/3/1 to 1/3/4

device(config-lag-blue)# trunk-threshold 3

In this example, if the number of active ports drops below 3, then all the ports in the LAG group are
disabled.

Syntax: [no] trunk-threshold number

You can specify a threshold from 1 (the default) up to the number of ports in the LAG group.

When a LAG is shut down because the number of ports drops below the configured threshold, the LAG
is kept intact and it is re-enabled if enough ports become active to reach the threshold.

NOTE
The trunk-threshold command should be configured only at one end of the trunk. If it is set on both
sides, link failures will result in race-conditions and the will not function properly.

NOTE
The trunk-threshold command cannot be used in conjunction with protected link groups.

NOTE
Use a short LACP timeout when setting the trunk-threshold value equal to the number of links in the
LAG or connecting to third party devices. See

Configuring an LACP timeout

on page 144.

Specifying the LAG threshold for a LAG group

FastIron Ethernet Switch Platform and Layer 2 Switching Configuration Guide

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