User manual

iSCSI GbE to SAS/SATA II RAID Subsystem
User Manual
99
4.9 Trunking and LACP
Link aggregation is the technique of taking several distinct Ethernet links to let them
appear as a single link. It has a larger bandwidth and provides the fault tolerance ability.
Beside the advantage of wide bandwidth, the I/O traffic remains operating until all
physical links fail. If any link is restored, it will be added to the link group automatically.
iSCSI subsystem implements link aggregation as LACP and Trunking.
1. LACP (IEEE 802.3ad): The Link Aggregation Control Protocol (LACP) is a part of
IEEE specification 802.3ad. It allows bundling several physical ports together to
form a single logical channel. A network switch negotiates an automatic bundle by
sending LACP packets to the peer. Theoretically, LACP port can be defined as active
or passive. iSCSI subsystem controller implements it as active mode which means
that LACP port sends LACP protocol packets automatically. Please notice that using
the same configurations between iSCSI subsystem controller and gigabit switch.
The usage occasion of LACP:
A. It’s necessary to use LACP in a network environment of multiple switches. When
adding new devices, LACP will separate the traffic to each path dynamically.