H3C Technologies H3C S12500-X Series Switches - Manual (Page 48)

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Link aggregation modes
Link aggregation has dynamic and static modes:
• Static aggregation mode—Aggregation is stable. The aggregation state of the member ports are
not affected by the peer ports.
• Dynamic aggregation mode—The peering system automatically maintains the aggregation state of
the member ports, thus reducing the workload of administrators.
An aggregation group in static mode is called a "static aggregation group" and an aggregation group
in dynamic mode is called a "dynamic aggregation group."
Aggregating links in static mode
The static link aggregation process comprises:
• Choosing a reference port
• Setting the aggregation state of each member port
Choosing a reference port
When setting the aggregation state of the ports in an aggregation group, the system automatically picks
a member port as the reference port. A Selected port must have the same operational key and attribute
configurations as the reference port.
The system chooses a reference port from the member ports that are in up state with the same attribute
configurations as the aggregate interface.
The candidate ports are sorted in the following order:
1. Highest port priority
2. Full duplex/high speed
3. Full duplex/low speed
4. Half duplex/high speed
5. Half duplex/low speed
The candidate port at the top is chosen as the reference port. If two ports have the same port priority,
duplex mode, and speed, the original Selected port is chosen. If more than one such original Selected
port exists, the one with the lower port number is chosen.
Setting the aggregation state of each member port
After a static aggregation group has reached the limit on Selected ports, any port that joins the group is
placed in Unselected state to avoid traffic interruption on the existing Selected ports.