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Cisco Systems IntelligentGigabit Ethernet Switch Modules for the IBMBladeCenter, Software Configuration Guide
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Chapter24 Configuring EtherChannels and Layer2 Trunk Failover
Configuring EtherChannels
If more than eight links are configured for an EtherChannel group, the so ftware determines which of the
hot standby ports to make active based on LACP port-priority and Port ID.
All ports default to the same port priority. You can change the port priority of LACP EtherChannel ports
to specify which hot standby links become active first by using the lacp port-priority interface
configuration command to set the port priority to a value lower than the default of 32768.
The hot standby ports that have lower port ID numbers become active in the channel first unless the port
priority is configured to be a lower number than the default value o f 32768.
Note If LACP cannot aggregate all the ports that are compatible (for example, the remote system might have
more restrictive hardware limitations), all the ports that cannot be actively included in the EtherChannel
are put in a hot standby state. They are used only if one of the channeled ports fails.
Configuring the LACP System Priority
You can set the system priority for all of the EtherChannels that are configured for LACP by using the
lacp system-priority privileged EXEC command. The range is from 1 to 65535.
Note The lacp system-priority command is global. You cannot set a system priority for each
LACP-configured channel separately.
We recommend using this command only when there are a combination of LACP-configured
EtherChannels that are in both active and standby modes.
Beginning in privileged EXEC mode, follow these steps to configure the LACP system priority:
Command Purpose
Step1 configure terminal Enter global configuration mode.
Step2 lacp system-priority priority-value Select the LACP system priority value.
For priority-value, the range is 1 to 65535. By default, the priority
value is 32768. The lower the range, the higher the system priority.
The switch with the lower system priority value determines which
links between LACP partner switches are active and which are in
standby for each LACP EtherChannel.
Step3 end Return to privileged EXEC mode.
Step4 show running-config
or
show lacp channel-group-number internal
Verify your entries.
Step5 copy running-config startup-config (Optional) Save your entries in the configuration file.