IBM SAN32M1, Installation And Service Manual

Page: 590 / 626

SAN32M1 Fabric Switch Installation and Service Manual 558
logical partition
LPAR. A processor hardware subset defined to support the operation
of a system control program, and can be used without affecting any of
the applications in another partition (D).
logical port address In a director or switch, the address used to specify port connectivity
parameters and to assign link addresses for the attached channels
and control units.
logical switch number LSN. A two-digit number used by the I/O configuration program
(IOCP) to identify a director or switch (D).
logical unit number LUN. In Fibre Channel addressing, a logical unit number is a number
assigned to a storage device which, in combination with the storage
device’s node port’s world-wide name, represents a unique identifier
for a logical device on a storage area network. Peripherals use LUNs
to represent addresses. A small computer system interface (SCSI)
device’s address can have up to eight LUNs.
login server Entity within the Fibre Channel fabric that receives and responds to
login requests.
longwave Lasers or light-emitting diodes (LEDs) that emit light with wave-
lengths around 1300 nm. When using single mode (9 nm) fiber, long-
wave lasers can be used to achieve lengths greater than 2 Km.
loopback plug In a fiber optic environment, a type of duplex connector used to wrap
the optical output signal of a device directly to the optical input. Con-
trast with
protective plug . Synonymous with wrap plug .
loopback test Test that checks attachment or control unit circuitry, without checking
the mechanism itself, by returning the output of the mechanism as
input.
LPAR See logical partition .
LSN See logical switch number .
LUN See logical unit number .
M
MAC address
See media access control address .