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Catalyst 2960 Switch SoftwareConfiguration Guide
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Chapter30 Configuring EtherChannels
Configuring EtherChannels
Determining which ports are active and which are hot standby is a two-step p rocedure. First the system
with a numerically lower system priority and system-id is placed in charge of the decision. Next, that
system decides which ports are active and which are hot standby, based on its values for port priority and
port number. The port-priority and port-number values for the other system are not used.
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 30-15 and the “Configuring the LACP Port Priority” section on
page 30-15.
Configuring the LACP System Priority
You can configure the system priority for all 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 a ffect 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.
Configuring the LACP Port Priority
By default, all ports use the same port priority. If the local system has a lower value for the system
priority and the system ID than the remote system, you can affect which of the hot-standby links become
active first by changing the port priority of LACP EtherChannel ports to a lower value than the default.
The hot-standby ports that have lower port numbers become active in the cha nnel first. 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).
Command Purpose
Step1 configure terminal Enter global configuration mode.
Step2 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.
Step3 end Return to privileged EXEC mode.
Step4 show running-config
or
show lacp sys-id
Verify your entries.
Step5 copy running-config startup-config (Optional) Save your entries in the configuration file.