H3C S5830V2 series, Руководство по настройке, Страница: 63 / 318

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LACP
LACP uses LACPDUs to exchange aggregation information between LACP-enabled devices.
Each member port in an LACP-enabled aggregation group exchanges information with its peer. When a
member port receives an LACPDU, it compares the received information with information received on the
other member ports. In this way, the two systems reach an agreement on which ports are placed in
Selected state.
LACP functions
LACP offers basic LACP functions and extended LACP functions, as described in Table 3 .
Table 3 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 priority, port number, and operational key.
Extended LACP
functions
Implemented by extending the LACPDU with new TLV fields. This is how the LACP
MAD mechanism of the IRF feature is implemented.
The switch series can participate in LACP MAD as either an IRF member device or an
intermediate device.
For more information about IRF and the LACP MAD mechanism, see
IRF
Configuration Guide .
LACP operating modes
LACP can operate in active mode or passive mode.
When LACP is operating in passive mode on a local member port and its peer port, both ports cannot
send LACPDUs. When LACP is operating in active mode on the port on either end of a link, both ports
can send LACPDUs.
LACP priorities
LACP priorities include system LACP priority and port priority, as described in Table 4 . The smaller the
priority value, the higher the priority.
Table 4 LACP priorities
Type Description
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, after which the system that has lower priority
sets port state accordingly.
Port priority
Determines the likelihood of a member port to be a Selected port on a system. The
higher port priority, the higher the likelihood of selection.
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 has not received LACPDUs from the peer within the LACP timeout interval, the
member port considers the peer as failed.