HP A5830 Configuration Manual page 35

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 port attributes and class-two
configurations as the reference port.
LACP
The IEEE 802.3ad LACP enables dynamic aggregation of physical links. It uses LACPDUs for exchanging
aggregation information between LACP-enabled devices.
LACP functions
1.
The IEEE 802.3ad LACP offers basic LACP functions and extended LACP functions, as described in
3.
Table 3 Basic and extended LACP functions
Category
Basic LACP
functions
Extended LACP
functions
For more information about IRF, member switches, intermediate devices, and the LACP MAD mechanism,
see IRF Configuration Guide.
LACP priorities
2.
LACP priorities have the following types: system LACP priority and port aggregation priority.
Table 4 LACP priorities
Type
System LACP
priority
Port aggregation
priority
LACP timeout interval
3.
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. Configure the LACP timeout interval as
either the short timeout interval (1 second) or the long timeout interval (30 seconds).
Description
Implemented through the basic LACPDU fields, including the system LACP priority, system
MAC address, port aggregation priority, port number, and operational key.
Each member port in a LACP-enabled aggregation group exchanges the preceding
information with its peer. When a member port receives an LACPDU, it compares the
received information with the information received on the other member ports. In this way,
the two systems reach an agreement on which ports should be placed in the Selected
state.
Implemented by extending the LACPDU with new Type/Length/Value (TLV) fields. This is
how the LACP MAD mechanism of the IRF feature is implemented. The A5830 Switch
Series can participate in LACP MAD as either an IRF member switch or an intermediate
device.
Description
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
Determines the likelihood of a member port to be selected on a
system
The higher the port aggregation priority, the higher the likelihood
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Table
Remarks
The smaller the
priority value,
the higher the
priority