Installation guide

ISR651101-00 H Glossary-5
iSR6200 QLogic intelligent Storage Router (iSR)
Installation Guide
ioctl
Input/output control. A system call in
UNIX
®
/Linux systems that allows an appli-
cation to control or communicate with a
device driver outside usual read/write
operations.
IP
Internet Protocol. A method by which data
is sent from one computer to another over
the Internet. IP specifies the format of
packets, also called datagrams, and the
addressing scheme.
iSCSI
Internet small computer system interface.
Protocol that encapsulates data into IP
packets to send over Ethernet connec-
tions.
iSNS
Internet simple name service (iSNS) is
used for discovery and management of
IP-based SANs.
L_Port
Loop port. Does arbitrated loop functions
and protocols. NL_Ports and FL_Ports are
examples of loop-capable ports. See
E_Port, F_Port, FL_Port, G_Port, N_Port,
NL_Port.
latency
A measure of how fast a transaction
travels through the router.
LED
Light emitting diode. Status indicator on a
switch or other device.
light emitting diode
See LED.
LIP
Loop initialization process. The initializa-
tion process in an arbitrated loop that
occurs when the loop is powered up or a
new device is added. One function of a LIP
is to assign addresses. All data transmis-
sion on the loop is suspended during a LIP.
load balancing
A software feature that improves system
performance by balancing device access
between multiple ports for maximum
resource efficiency.
logical unit number
See LUN.
loop initialization process
See LIP.
loopback
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.
maintenance button
Multifunction momentary switch on the
front panel of the router.