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Catalyst 3560 Switch Software Configuration Guide
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Chapter 29 Configuring EtherChannels
Configuring EtherChannels
In priority comparisons, numerically lower values have higher priority. The priority decides which ports
should be put in standby mode when there is a hardware limitation that prevents all compatible ports
from aggregating.
Ports are considered for active use in aggregation in link-priority order starting with the port attached to
the highest priority link. Each port is selected for active use if the preceding higher priority selections
can also be maintained. Otherwise, the port is selected for standby mode.
You can change the default values of the LACP system priority and the LACP port priority to affect how
the software selects active and standby links. For more information, see the
“Configuring the LACP
System Priority” section on page 29-18
and the
“Configuring the LACP Port Priority” section on
page 29-19
.
Configuring the LACP System Priority
You can configure the system priority for all of the EtherChannels that are enabled for LACP by using
the lacp system-priority global configuration command. You cannot configure a system priority for
each LACP-configured channel. By changing this value from the default, you can affect how the software
selects active and standby links.
You can use the show etherchannel summary privileged EXEC command to see which ports are in the
hot-standby mode (denoted with an H port-state flag).
Beginning in privileged EXEC mode, follow these steps to configure the LACP system priority. This
procedure is optional.
To return the LACP system priority to the default value, use the no lacp system-priority global
configuration command.
Command
Purpose
Step 1
configure terminal
Enter global configuration mode.
Step 2
lacp system-priority priority
Configure the LACP system priority.
For priority, the range is 1 to 65535. The default is 32768.
The lower the value, the higher the system priority.
Step 3
end
Return to privileged EXEC mode.
Step 4
show running-config
or
show lacp sys-id
Verify your entries.
Step 5
copy running-config startup-config
(Optional) Save your entries in the configuration file.