H3C Technologies H3C WX6000 Series Access Controllers - Manual (Page 127)

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Link Aggregation Overview
The term switch in this document refers to a switch in a generic sense or an access controller
configured with the switching function unless otherwise specified.
This chapter covers these topics:
z
Link Aggregation
z
Approaches to Link Aggregation
z
Load Sharing in a Link Aggregation Group
z
Aggregation Port Group
Link Aggregation
Link aggregation allows you to increase bandwidth by distributing traffic on the member ports in an
aggregation group. In addition, it provides reliable connectivity because these member ports can
dynamically back up each other.
LACP
Link Aggregation Control Protocol (LACP) is defined in IEEE 802.3ad. Link aggregation control protocol
data unit (LACPDU) is used for exchanging information among LACP-enabled devices.
After LACP is enabled on a port, the port sends LACPDUs to notify the remote system of its system
LACP priority, system MAC address, port LACP priority, port number, and operational key. Upon receipt
of an LACPDU, the remote system compares the received information with the information received on
other ports to determine the ports that can operate as selected ports. This allows the two systems to
reach agreement on the states of the related ports
When aggregating ports, link aggregation control automatically assigns each port an operational key
based on its rate, duplex mode, and other basic configurations. In an LACP aggregation group, all ports
share the same operational key; in a manual or static LACP aggregation, the selected ports share the
same operational key.
Consistency Considerations for Ports in an Aggregation
To participate in traffic sharing, member ports in an aggregation group must use the same
configurations with respect to STP, QoS, GVRP, Q-in-Q, BPDU tunnel, VLAN, port attributes, MAC
address learning, and so on as shown in the following table.