Reference port, Lacp protocol – H3C Technologies H3C S12500 Series Switches User Manual
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warning message every time you attempt to change a class-two configuration setting on a member
port.
•
Class-one configurations—Include settings that do not affect the aggregation state of the member
port even if they are different from those on the aggregate interface. GVRP and MSTP settings are
examples of class-one configurations.
Reference port
When setting the aggregation state of the ports in an aggregation group, the system automatically picks
a member port as the reference. This port is called the reference port of the aggregation group. The port
attribute and class-two configurations of every other member port are compared with those of the
reference port.
LACP protocol
The IEEE 802.3ad Link Aggregation Control Protocol (LACP) enables dynamic aggregation of physical
links. It uses link aggregation control protocol data units (LACPDUs) for exchanging aggregation
information between LACP-enabled network devices.
1.
LACP functions
Based on the fields carried in LACPDUs, the functions delivered by the IEEE 802.3ad LACP include
basic LACP functions and extended LACP functions, as described in
.
Table 13 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 aggregation 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 Type/Length/Value (TLV)
fields. This is how the LACP multi-active detection (MAD) mechanism of the
Intelligent Resilient Framework (IRF) feature is implemented.
•
If a switch supports both LACP extensions and IRF, it can participate in LACP
MAD either as an IRF member switch or an intermediate switch.
•
If a switch supports LACP extensions but not IRF, it can participate in LACP
MAD only as an intermediate switch.
For more information about IRF, IRF member switches, intermediate switches, and the LACP MAD
mechanism, see IRF Configuration Guide.
2.
LACP priorities
There are two types of LACP priorities: system LACP priority and port aggregation priority, as
described in