Manual Link Aggregation - 3Com MSR 50 Series Configuration Manual

Manual Link Overview
Aggregation
In the manual aggregation approach, aggregation groups are created
administratively. On the ports in a manual aggregation group, LACP is disabled.
Port states in a manual aggregation
In a manual aggregation group, ports are either selected or unselected. Selected
ports can receive and transmit data frames whereas unselected ones cannot.
Among all selected ports, the one with the lowest port number is the master port
and others are member ports.
When setting the state of ports in a manual aggregation group, the system
considers the following:
Select a port from the ports in up state, if any, in the order of full duplex/high
■
speed, full duplex/low speed, half duplex/high speed, and half duplex/low
speed, with the 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. Then, place those ports in up state with the same
speed/duplex pair, link state and basic configuration in selected state and all
others in unselected state.
When all ports in the group are down, select the port with the lowest port
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number as the master port and set all ports (including the master) in unselected
state.
Place the ports that cannot aggregate with the master in unselected state, for
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example, as the result of the cross-board aggregation restriction.
Manual aggregation limits the number of selected ports in an aggregation group.
When the limit is exceeded, the system changes the state of selected ports with
greater port numbers to unselected until the number of selected ports drops
under the limit.
In addition, unless the master port should be selected, a port that joins the group
after the limit is reached will not be placed in selected state even if it should be in
normal cases. This is to prevent the ongoing service on selected ports from being
interrupted. You need to avoid the situation however as the selected/unselected
state of a port may become different after a reboot.
n
The maximum number of selected ports in a manual aggregation group varies by
device.
Port Configuration Considerations in manual aggregation
As mentioned above, in a manual aggregation group, only ports with
configurations consistent with those of the master port can become selected.
These configurations include port rate, duplex mode, link state and other basic
configurations described in
Aggregation" on page
You need to maintain the basic configurations of these ports manually to ensure
consistency. As one configuration change may involve multiple ports, this can
become troublesome if you need to do that port by port. As a solution, you may
add the ports to an aggregation group where you can make configuration for all
member ports.
"Consistency Considerations for Ports in an
346."
Approaches to Link Aggregation 347