H3C Technologies H3C S10500 Series Switches - Manual (Page 45)

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NOTE:
•
Class-two configurations made on an aggregate interface are automatically synchronized to all
member ports of the interface. These configurations are retained on the member ports even after the
aggregate interface is removed.
• Any class-two configuration change might affect the aggregation state of link aggregation member
ports and ongoing traffic. To be sure that you are aware of the risk, the system displays a warning
message every time you attempt to change a class-two configuration setting on a member port.
• Class-one configurations 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.
NOTE:
The class-one configuration for a member port is effective only when the member port leaves the
aggregation group.
Reference port
When setting the aggregation state of the ports in an aggregation group, the system automatically picks
a member port as the reference port. A Selected port must have the same port attributes and class-two
configurations as the reference port.
LACP
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 devices.
1. LACP functions
The IEEE 802.3ad 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 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.
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. The S10500 Switch Series can participate in LACP MAD as
either an IRF member switch or an intermediate device.
NOTE:
For more information about IRF, member switches, intermediate devices, and the LACP MAD mechanism,
see
IRF Configuration Guide.
2. LACP priorities
LACP priorities have the following types: system LACP priority and port aggregation priority.