HP 316095-B21 - StorageWorks Edge Switch 2/24 Service Manual page 292

Glossary
logical port address
In a Director or Edge 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 Edge 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 wavelengths around 1300 nm.
When using single mode (9 nm) fiber, longwave 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. Contrast with
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.
Glossary–32
protective plug. Synonymous with
edge switch 2/24 service manual
wrap