McDATA 3032, 3232 M

g-32 McDATA® Sphereon 3032 and 3232 Fabric Switches Installation and Service Manual

Glossary

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.

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.