HP 6125G Configuration Manual page 40

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. You can configure
the LACP timeout interval as either the short timeout interval (1 second) or the long timeout interval
(30 seconds).
Link aggregation modes
Link aggregation has the following modes: dynamic and static. Dynamic link aggregation uses LACP
and static link aggregation does not.
Table 5 A comparison between static and dynamic aggregation modes
Aggregation
mode
Static
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 multi-active detection (MAD) mechanism of the Intelligent Resilient Framework
(IRF) feature is implemented. The 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.
Table 5
LACP status on
Pros
member ports
Aggregation is stable. Peers do
Disabled not affect the aggregation state of
the member ports.
compares the two aggregation modes.
31
Remarks
The smaller the
priority value,
the higher the
priority.
Cons
The member ports do not adjust the
aggregation state according to
that of the peer ports. The
administrator must manually
maintain link aggregations.