3Com Switch 7750 Configuration Guide

Link Aggregation Configuration 191
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For a static LACP aggregation group or a manual aggregation group, you are
recommended not to cross cables between the two devices at the two ends of the
aggregation group. For example, suppose port 1 of the local device is connected
to port 2 of the peer device. To avoid cross-connecting cables, do not connect port
2 of the local device to port 1 of the peer device. Otherwise, packets may be lost.
Note that:
■ LACP cannot be enabled on an existing port in a manual aggregation group.
■ You can add a LACP-enabled port to a manual aggregation group. In this case,
the system will disable LACP on the port automatically. Similarly, when you add
a LACP-disabled port to a static aggregation group, the system will enable
LACP on the port automatically.
Configuring a Dynamic
LACP Aggregation
Group
A dynamic LACP aggregation group is automatically created by the system based
on LACP-enabled ports. The adding and removing of ports to/from a dynamic
aggregation group are automatically accomplished by LACP.
You need to enable LACP on the ports whom you want to participate in dynamic
aggregation of the system, because, only when LACP is enabled on those ports at
both ends, can the two parties reach agreement in adding/removing ports to/from
dynamic aggregation groups.
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Enabling LACP on a member port of a manual aggregation group will not take
effect.
■ If an existing aggregation group contains no port, the type of the aggregation
group is set to the latest set type.
■ If an aggregation group contains ports, you can only change a dynamic
aggregation group or static aggregation group into a manual aggregation
group, or change a dynamic aggregation group into a static aggregation
group.
Table 124 Configure a dynamic LACP aggregation group
Operation Command Description
Enter system view system-view -
Configure a description for an
aggregation group
link-aggregation group
agg-id description agg-name
Optional
By default, an aggregation
group has no description.
Configure the system priority lacp system-priority
system-priority
Optional
By default, the system priority
is 32,768.
Enter Ethernet port view interface interface-type
interface-number
-
Enable LACP on the port lacp enable Required
By default, LACP is disabled
on a port.
Configure the port priority lacp port-priority
port-priority
Optional
By default, the port priority is
32,768.