H3C S5120-EI Series, Operation Manual

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1-5
aggregation group, while a link aggregation group operating in dynamic mode is called a dynamic link
aggregation group.
Table 1-4 compares the two aggregation modes.
Table 1-4
A comparison between static and dynamic aggregation modes
Aggregation
mode
LACP status
on member
ports
Pros Cons
Static Disabled
Aggregation is stable. The
aggregation state of the member
ports is not affected by their
peers.
The member ports cannot
change their aggregation
state in consistent with their
peers. The administrator
needs to manually maintain
link aggregations.
Dynamic Enabled
The administrator does not need
to maintain link aggregations. The
peer systems maintain the
aggregation state of the member
ports automatically.
The aggregation state of
member ports is easily
affected by the network
environment, which makes
dynamic aggregation
instable.
In a dynamic link aggregation group:
z
A selected port can receive and send LACPDUs.
z
An unselected port can receive and send LACPDUs only if it is up and have the same class-two
configurations as the aggregate interface.
Aggregating Links in Static Mode
LACP is disabled on the member ports in a static aggregation group. The aggregation state of the
member ports must be maintained manually.
Static link aggregation comprises:
z
Selecting a reference port
z
Setting the aggregation state of each member port
Selecting a reference port
The system selects a reference port from the member ports that are in the up state and have the same
class-two configurations as the aggregate interface.
The candidate ports are sorted by duplex and speed in this order: full duplex/high speed, full duplex/low
speed, half duplex/high speed, and half duplex/low speed. The one at the top is selected as the
reference port. If two ports have the same duplex mode and speed, the one with the lower port number
wins out.
Setting the aggregation state of each member port
After selecting the reference port, the static aggregation group sets the aggregation state of each
member port as shown in
Figure 1-2 .