HP V1910 Switch Series User Manual page 226

 In an aggregation group, the port to be a selected port must be the same as the reference port in
port attributes, and class-two configurations. To keep these configurations consistent, you should
configure the port manually.
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 more information about class-two configurations, see

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. At the
same time, all member ports leave the aggregation group.
"Class-two
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configurations."