HP 1910 User Manual page 233

CAUTION:
A port that joins the aggregation group after the limit on the number of Selected ports has been reached
will not be placed in Selected state even if it should be in normal cases. This can prevent the ongoing traffic
on the current Selected ports from being interrupted. You should avoid the situation however, as this may
cause the Selected/Unselected state of a port to change after a reboot.
Dynamic aggregation mode
LACP is enabled on member ports in a dynamic aggregation group.
In a dynamic aggregation group,
A Selected port can receive and transmit LACPDUs.
•
• An Unselected port can receive and send LACPDUs only if it is up and with the same configurations
as those on the aggregate interface.
In a dynamic aggregation group, the system sets the ports to Selected or Unselected state in the following
steps:
The local system (the actor) negotiates with the remote system (the partner) to determine port state
1.
based on the port IDs on the end with the preferred system ID. The following negotiation procedure
applies:
Compare the system ID (comprising the system LACP priority and the system MAC address) of
the actor with that of the partner. The system with the lower LACP priority wins. If they are the
same, compare the system MAC addresses. The system with the smaller MAC address wins.
Compare the port IDs of the ports on the system with the smaller system ID. A port ID comprises
a port LACP priority and a port number. First compare the port LACP priorities. The port with the
lower LACP priority wins. If two ports are with the same LACP priority, compare their port
numbers. The port with the smaller port number is selected as the reference port.
If a port (in up state) is with the same port attributes and class-two configuration as the
reference port, and the peer port of the port is with the same port attributes and class-two
configurations as the peer port of the reference port, consider the port as a candidate selected
port; otherwise set the port to the Unselected state.
The number of Selected ports that an aggregation group can contain is limited. When the
number of candidate selected ports is under the limit, all the candidate selected ports are set
to Selected state. When the limit is exceeded, the system selects the candidate selected ports
with smaller port IDs as the Selected ports, and set other candidate selected ports to
Unselected state. At the same time, the peer device, being aware of the changes, also changes
the state of its ports.
Set the ports that cannot aggregate with the reference port to the Unselected state, for example, as
2.
the result of the inter-board aggregation restriction.
NOTE:
For static and dynamic aggregation modes:
• 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.
Changing a port attribute or class-two configuration setting of a port may cause the select state of the
•
port and other member ports to change and affect services. HP recommends that you do that with
caution.
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