Configuring LACP
LACP Operation
4-94 Matrix NSA Series Configuration Guide

4.5 CONFIGURING LACP

Using multiple links simultaneously to increase bandwidth is a desirable switch feature, which can
be accomplished if both sides agree on a set of ports that are being used as a Link Aggregation
Group (LAG). Once a LAG is formed from selected ports, prob lems with looping can be avoi ded
since the Spanning Tree can treat this LAG as a single port.
Enabled by default on Matrix devices, the Link Aggregation Control Protocol (LACP) logically
groups interfaces together to create a greater bandwidth uplink, or link aggregation, according to
the IEEE 802.3ad standard. This standard allows the swit ch to determine which ports are in LAGs
and configure them dynamically. Since the protocol is based on the IEEE 802.3ad specification,
any switch from any vendor that supports this standard can aggregate links automatically.
802.3ad LACP aggregations can also be run to end-users (i.e.; a server) or to a router.

4.5.1 LACP Operation

For each aggregatable port in the device, LACP:
•Maintains configuration information (reflecting the inherent properties of the individual links as
well as those established by management) to control aggregation.
•Exchanges configuration information with other devices to allocate the link to a Link
Aggregation Group (LAG).
•Attaches the port to the aggregator used by the LAG, and detaches the port from the aggre gator
when it is no longer used by the LAG.
•Uses information from the partner device’s link aggregation control entity to decide whether to
aggregate ports.
CAUTION: Link aggregati on configura tion sh ou ld only be pe rformed by person ne l who
are knowledgeable about S pannin g T ree and Link Aggregation, and fully un derstand the
ramifications of modifications beyond device defaults. Otherwise, the pr op e r oper at ion
of the network coul d be at risk.
NOTE: Earlier (proprietary) implementations of port aggregation referred to groups of
aggregated ports as “trunks”.
NOTE: A given link is allocated to, at most, one Link Aggregation Group (LAG) at a
time. The allocation mechanism attempts to maximize aggregation, subject to
management controls.