IBM F16 User Manual page 108

IDLE. Continuous transmission of an ordered set over
a Fibre Channel link when no data is being transmitted,
to keep the link active and maintain bit, byte, and word
synchronization.
IETF. Internet Engineering Task Force.
information unit (IU). A set of information as defined
by either upper-level process protocol definition or
upper-lever protocol mapping.
initiator. A server or workstation on a Fibre Channel
network that initiates communications with storage
devices. See also target.
in-order delivery (IOD). A parameter that, when set,
guarantees that frames are either delivered in order or
dropped.
integrated fabric. The fabric created by six switches
cabled together and configured to handle traffic as a
seamless group.
Internet protocol (IP). In the Internet suite of
protocols, a connectionless protocol that routes data
through a network or interconnected networks and acts
as an intermediary between the higher protocol layers
and the physical network.
inter-switch link (ISL). A Fibre Channel link that
connects two switches (a link from the expansion port
(E_port) of one switch to the E_port of another).
IOD. See in-order delivery.
IP. See Internet protocol.
IPA. Initial process associator.
ISL. See inter-switch link.
ISL Trunking. A feature that enables distribution of
traffic over the combined bandwidth of up to four
inter-switch links (ISLs) (between adjacent switches),
while preserving in-order delivery. A set of trunked ISLs
is called a trunking group; each port employed in a
trunking group is called a trunking port. See also master
port.
isolated E_port. An expansion port (E_port) that is
online but not operational between switches due to
overlapping domain ID or nonidentical parameters such
as error delay timeout values (E_D_TOVs). See also
expansion port.
IU. See information unit.
K28.5. A special 10-bit character used to indicate the
beginning of a transmission word that performs Fibre
Channel control and signaling functions. The first seven
bits of the character are the comma pattern. See also
comma.
LAN. See local area network.
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IBM TotalStorage SAN Switch: 2109 Model F16 User's Guide
latency. The period of time required to transmit a
frame, from the time it is sent until it arrives.
LED. See light-emitting diode.
light-emitting diode (LED). A semiconductor chip that
gives off visible or infrared light when activated.
link. As applies to Fibre Channel, a physical
connection between two ports, consisting of both
transmit and receive fibers. See also circuit.
link services. A protocol for link-related services.
LIP. See loop initialization primitive.
LM_TOV. See loop master timeout value.
local area network (LAN). A computer network
located on a user's premises within a limited
geographical area. (T)
logical unit number (LUN). An identifier used on a
small computer systems interface (SCSI) bus to
distinguish among up to eight devices (logical units) with
the same SCSI ID.
long wavelength (LWL). A type of fiber optic cabling
that is based on 1300 mm lasers and supports link
speeds of 1.0625 Gbps. Can also refer to the type of
gigabit interface converter (GBIC) or small form-factor
pluggable (SFP). See also short wavelength.
loop. A configuration of devices that are connected to
the fabric by way of a fabric loop port (FL_port)
interface card.
loop failure. Loss of signal within a loop for any
period of time, or loss of synchronization for longer than
the timeout value.
loop_ID. A hexadecimal value representing one of the
127 possible arbitrated loop physical address (AL_PA)
values in an arbitrated loop.
loop initialization. The logical procedure used by a
loop port (L_port) to discover its environment. Can be
used to assign arbitrated loop physical address (AL_PA)
addresses, detect loop failure, or reset a node.
loop initialization primitive (LIP). The signal used to
begin initialization in a loop. Indicates either loop failure
or resetting of a node.
looplet. A set of devices connected in a loop to a port
that is a member of another loop.
loop master timeout value (LM_TOV). The minimum
time that the loop master waits for a loop initialization
sequence to return.
loop mode. One of the modes for a loop port (L_port).
An L_port is in loop mode when it is in an arbitrated
loop and is using loop protocol. An L_port in loop mode