Operation Manual – Link Aggregation
H3C S3610&S5510 Series Ethernet Switches
Chapter 1 Link Aggregation Overview
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Chapter 1 Link Aggregation Overview
This chapter covers these topics:
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Approaches to Link Aggregation
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Load Sharing in a Link Aggregation Group
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1.1 Link Aggregation
Link aggregation allows you to increase bandwidth by distributing incoming/outgoing
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.
1.1.1 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.
1.1.2 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.
