H3C Technologies H3C S7500E Series Switches - Manual (Page 128)

11-4
Table 11-2 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 Type/Length/Value (TLV) fields.
This is how the LACP multi-active detection (MAD) mechanism of the Intelligent
Resilient Framework (IRF) feature is implemented.
Switches of the S7500E series that support extended LACP functions can function
as both member devices and intermediate devices in LACP MAD implementation.
For details about IRF, member devices, intermediate devices, and the LACP MAD mechanism, see
IRF Configuration in the IRF Configuration Guide.
2) LACP priorities
There are two types of LACP priorities: system LACP priority and port LACP priority, as described in
Table 11-3 .
Table 11-3 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.
Link aggregation modes
There are two link aggregation modes: dynamic and static. Dynamic link aggregation uses LACP while
static link aggregation does not. A link aggregation group operating in static mode is called a static link
aggregation group, while a link aggregation group operating in dynamic mode is called a dynamic link
aggregation group.
Table 11-4 compares the two aggregation modes.