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Aggregating links in static mode, Choosing a reference port – H3C Technologies H3C WX5500E Series Access Controllers User Manual

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The smaller the priority value, the higher the priority.

Table 5 LACP priorities

Type Description

System LACP
priority

Used by two peer devices (or systems) to determine which one is superior in link
aggregation.
In dynamic link aggregation, the system that has higher system LACP priority sets
the Selected state of member ports on its side first, and then the system that has

lower priority sets the port state accordingly.

Port aggregation
priority

Determines the likelihood of a member port to be selected on a system. The higher
the port aggregation priority, the higher the likelihood.

LACP timeout interval
The LACP timeout interval specifies how long a member port waits to receive LACPDUs from the
peer port. If a local member port fails to receive LACPDUs from the peer within three times the

LACP timeout interval, the member port assumes that the peer port has failed. You can configure
the LACP timeout interval as either the short timeout interval (1 second) or the long timeout interval

(30 seconds).

Aggregating links in static mode

LACP is disabled on the member ports in a static aggregation group. You must manually maintain the

aggregation state of the member ports.
When you aggregate links in static mode, follow these guidelines:

To make sure that you have stable aggregation state and service continuity, do not change port

attributes or class-two configurations on any member port.

If 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 current Selected ports. Avoid this

situation, however, because it might cause the aggregation state of a port to change after a reboot.

The static link aggregation process comprises the following tasks:

Choosing a reference port

Setting the aggregation state of each member port

Choosing a reference port

The system chooses a reference port from the member ports that:

Are in up state.

Have the same class-two configurations as the aggregate interface.

The candidate ports are sorted by aggregation priority, duplex, and speed in the following order:

Lowest aggregation priority value

Full duplex/high speed

Full duplex/low speed

Half duplex/high speed

Half duplex/low speed