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User’s Guide—Converged Network Adapters and Intelligent Ethernet Adapters
FastLinQ 3400 and 8400 Series
Layer 2
Refers to the data link layer of the multilay-
ered communication model, Open
Systems Interconnection (OSI). The
function of the data link layer is to move
data across the physical links in a network,
where a switch redirects data messages at
the layer 2 level using the destination MAC
address to determine the message desti-
nation.
LED
Light-emitting diode. Status indicator on a
switch, router, adapter, or other device.
light-emitting diode
See
load balancing
Adjusting components to spread demands
evenly across a system’s physical
resources, and thereby optimizing perfor-
mance. Load balancing can be done
manually or programmatically.
local area network
See
logical unit number
See
loopback
A diagnostic tool that routes transmit data
through a loopback connector back to the
same adapter.
LUN
Logical unit number, a subdivision of a
SCSI target. It is the small integer handle
that differentiates an individual disk drive
or partition (volume) within a common
SCSI target device such as a disk array.
Technically, a LUN can be a single
physical disk drive, multiple physical disk
drives, or a portion (volume) of a single
physical disk drive. However, LUNs are
typically not entire disk drives but rather
virtual partitions (volumes) of a RAID set.
Using LUNs, the Fibre Channel host can
address multiple peripheral devices that
may share a common controller.
MAC
Media access control. A data communica-
tion protocol sublayer, also known as the
medium access control, is a sublayer of
the Data Link Layer specified in the
seven-layer OSI model (Layer 2). It
provides addressing and channel access
control mechanisms that make it possible
for several terminals or network nodes to
communicate within a multipoint network,
typically a local area network (LAN) or
metropolitan area network (MAN). The
hardware that implements the MAC is
referred to as a medium access controller.
management information base
maximum transmission unit
.
media
Physical-layer information carriers. Fibre
Channel supports several different
physical media: copper, multimode optical,
and single-mode optical. All Fibre Channel
protocols are supported on all media.
media access control
.
message signaled interrupts
