Link Aggregation Overview; Link Aggregation - 3Com Switch 4800G 24-Port Configuration Manual

18

Link Aggregation

LACP
Consistency
Considerations for Ports
in an Aggregation
L A
INK GGREGATION
This chapter covers these topics:
"Link Aggregation" on page 161
■
"Approaches to Link Aggregation" on page 162
■
"Load Sharing in a Link Aggregation Group" on page 165
■
"Service Loop Group" on page 165
■
"Aggregation Port Group" on page 166
■
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.
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.
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.
O
VERVIEW