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Catalyst 2960 Switch SoftwareConfiguration Guide
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Chapter30 Configuring EtherChannels
Configuring EtherChannels
To return the priority to its default setting, use the no pagp port-priority interface configuration
command. To return the learning method to its default setting, use the no pagp learn-method interface
configuration command.
Configuring LACP Hot-Standby Ports
When enabled, LACP tries to configure the maximum number of LACP-compatible ports in a channel,
up to a maximum of 16 ports. Only eight LACP links can be active at one time. The software places any
additional links in a hot-standby mode. If one of the active links becomes inactive, a link that is in the
hot-standby mode becomes active in its place.
If you configure more than eight links for an EtherChannel group, the software automatically decides
which of the hot-standby ports to make active based on the LACP priority. To every link between systems
that operate LACP, the software assigns a unique priority made up of these elements (in priority order):
•LACP system priority
•System ID (the switch MAC address)
•LACP port priority
•Port number
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.
Step3 pagp learn-method physical-port Select the PAgP learning method.
By default, aggregation-port learning is selected, which means
the switch sends packets to the source by using any of the ports
in the EtherChannel. With aggregate-port learning, it is not
important on which physical port the packet arrives.
Select physical-port to connect with another switch that is a
physical learner. Make sure to configure the port-channel
load-balance global configuration command to src-mac as
described in the “Configuring EtherChannel Load Balancing”
section on page 30-12.
The learning method must be configured the same at both ends
of the link.
Step4 pagp port-priority priority Assign a priority so that the selected port is chosen for packet
transmission.
For priority, the range is 0 to 255. The default is 128. The higher
the priority, the more likely that the port will be used for PAgP
transmission.
Step5 end Return to privileged EXEC mode.
Step6 show running-config
or
show pagp channel-group-number internal
Verify your entries.
Step7 copy running-config startup-config (Optional) Save your entries in the configuration file.
Command Purpose