3Com Baseline 2928 PWR Plus User Manual page 250

Reference port: Select a port as the reference port from the ports that are in up state and with the
same class-two configurations as the corresponding aggregate interface. The selection order is as
follows: full duplex/high speed, full duplex/low speed, half duplex/high speed, and half duplex/low
speed, with full duplex/high speed being the most preferred. If two ports with the same duplex
mode/speed pair are present, the one with the lower port number wins out.
Port attribute configuration includes the configuration of the port rate, duplex mode, and link state.
For details about class-two configurations, see section Class-two configurations.
To guarantee a successful static aggregation, ensure that the ports at the two ends of each link to
be aggregated are consistent in the selected/unselected state; to guarantee a successful dynamic
aggregation, ensure that the peer ports of the ports aggregated at one end are also aggregated.
The two ends can automatically negotiate the selected state of the ports.
Removing a Layer 2 aggregate interface also removes the corresponding aggregation group.
Meanwhile, the member ports of the aggregation group, if any, leave the aggregation group.
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