HP 5820X Series

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Table 5 Basic and extended LACP functions
Category Description
Basic LACP functions
Implemented through the basic LACPDU fields, including the system LACP priority,
system MAC address, port LACP priority, port number, and operational key.
Each member port in a LACP-enabled aggregation group exchanges the above
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.
Extended LACP
functions
Implemented by extending the LACPDU with new TLV fields. This is how the LACP
multi-active detection (MAD) mechanism of the IRF feature is implemented. HP
5800 and HP 5820X switch series can participate in LACP MAD either as an IRF
member device or an intermediate device.
For more information about IRF, member devices, intermediate devices, and the LACP MAD mechanism,
see IRF Configuration Guide.
2. LACP priorities
LACP priorities have two types: system LACP priority and port LACP priority, as described in Table 6.
Table 6 LACP priorities
Type Description
Remarks
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 port state accordingly.
Port LACP priority
Determines the likelihood of a member port to be selected on a
system. The higher port LACP priority, the higher likelihood.
The smaller the
priority value,
the higher the
priority.
3. 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. Configure the LACP timeout interval either as the
short timeout interval (1 second) or long timeout interval (30 seconds).
Link aggregation modes
Link aggregation has two modes: dynamic and static. Dynamic link aggregation uses LACP and static link
aggregation does not. Table 7 c
ompares the two aggregation modes.