Glossary-6 Fabric Watch User’s Guide
Hub A fibre channel wiring concentrator that collapses a loop topology into a physical
star topology. Nodes are automatically added to the loop when active and
removed when inactive.
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.
Initiator A server or workstation on a fibre channel network that initiates communications
with storage devices. See also Targe t.
Integrated
Fabric The fabric created by a SilkWorm 6400, consisting of six SilkWorm 2250
switches cabled together and configured to handle traffic as a seamless group.
IOD In-order Delivery; a parameter that, when set, guarantees that frames are either
delivered in order or dropped.
ISL Interswitch Link; a fibre channel link from the E_Port of one switch to the E_Port
of another. See also E_Port, Cascade.
Isolated
E_Port An E_Port that is online but not operational due to overlapping domain IDs or
nonidentical parameters (such as E_D_TOVs). See also E_Port.
IU Information Unit; a set of information as defined by either upper-level process
protocol definition or upper-level protoco l mapping.
JBOD Just a Bunch Of Disks; indicates a number of disks connected in a single chassis
to one or more controllers. See also RAID.
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.
L_Port Loop Port; a node port (NL_Port) or fabric port (FL_Port) that has arbitrated loop
capabilities. An L_Port can be in one of two modes:
•Fabric mode Connected to a port that is not loop capable, and using fabric
protocol.
•Loop mode In an arbitrated loop and using loop protocol. An L_Port in loop
mode can also be in participating mode or non-participating mode.
See also Non-participating Mode, Participating Mode.
Latency The period of time required to transmit a frame, from the time it is sent until it
arrives.
Link As applies to fibre channel, a physical connection between two ports, consisting
of both transmit and receive fibres. See also Circuit.
Link Services A protocol for link-related actions.
LIP Loop Initialization Primitive; the signal used to begin initialization in a loop.
Indicates either loop failure or resetting of a node.
LM_TOV Loop Master Time-out Value; the minimum time that the loop master waits for a
loop initialization sequence to return.
Loop Failure Loss of signal within a loop for any period of t i me, or loss of synchronization for
longer than the time-out value.
Loop
Initialization The logical procedure used by an L_Port to discover its environment. Can be used
to assign AL_PA addresses, detect loop failure, or reset a node.