Table of Contents
Advertisement
arbitrate primitive signal (ARB). A primitive signal
that is transmitted as the fill word by a loop port (L_port)
to indicate that the L_port is arbitrating to access to the
loop. Applies only to the arbitrated loop topology.
arbitrated loop. A shared 100 MBps Fibre Channel
transport structured as a loop and supporting up to 126
devices and one fabric attachment. A port must
successfully arbitrate before a circuit can be
established.
arbitrated loop physical address (AL_PA). An 8–bit
value used to uniquely identify an individual port within
a loop. A loop can have one or multiple AL_PAs.
arbitration wait timeout value (AW_TOV). The
minimum time an arbitrating loop port (L_port) waits for
a response before beginning loop initialization.
area number. A number that is assigned to each
potential port location in the switch. Used to distinguish
ports that have the same port number but are on
different port cards.
ASIC. See application-specific integrated circuit.
asynchronous transfer mode (ATM). A broadband
technology for transmitting data over local area
networks (LANs) or wide area networks (WANs), based
on relaying cells of fixed size. Provides any-to-any
connectivity, and nodes can transmit simultaneously.
ATM. See asynchronous transfer mode.
auto-negotiate speed. Process that allows two
devices at either end of a link segment to negotiate
common features, speed (for example, 1 Gbps or 2
Gbps) and functions.
autoranging. A power supply that accommodates
different input voltages and line frequencies.
autosense. Process during which a network device
automatically senses the speed of another device.
AW_TOV. See arbitration wait timeout value.
B
backup FCS switch. The switch or switches assigned
as backup in case the primary fabric configuration
server (FCS) switch fails. See also fabric configuration
server switch and primary FCS switch.
bandwidth. (1) The total transmission capacity of a
cable, link, or system. Usually measured in bits per
second (bps). (2) The range of transmission frequencies
available to a network. See also throughput.
basic input/output system (BIOS). Code that controls
basic hardware operations, such as interactions with
diskette drives, hard disk drives, and the keyboard.
106
IBM TotalStorage SAN Switch: 2109 Model M12 Installation and Service Guide
BB_credit. See buffer-to-buffer credit.
beacon. When all the port light-emitting diodes (LEDs)
on a switch are set to flash from one side of the switch
to the other, to enable identification of an individual
switch in a large fabric. A switch can be set to beacon
by Telnet command or through Web Tools.
beginning running disparity. The disparity at the
transmitter or receiver when the special character
associated with an ordered set is encoded or decoded.
See also disparity.
BER. See bit error rate.
BIOS. See basic input/output system.
BISR. Built-in self-repair.
bit error rate (BER). The rate at which bits are
expected to be received in error. Expressed as the ratio
of error bits to total bits transmitted. See also error.
blade. One component in a system that is designed to
accept some number of components (blades). Blades
could be individual servers that plug into a
multiprocessing system or individual port cards that add
connectivity to a switch. A blade is typically a hot
swappable hardware device. See 16-port card.
blind-mate connector. A two-way connector used in
some switches to provide a connection between the
system board and the power supply.
block. As applies to fibre channel, upper-level
application data that is transferred in a single sequence.
bloom. Application-specific integrated circuit (ASIC)
technology that the 2109 Model M12 is based on.
boot flash. Flash memory that stores the boot code
and boot parameters. The processor runs its first
instructions from boot flash. Data is cached in random
access memory (RAM).
boot monitor. Code used to initialize the control
processor (CP) environment after powering on.
Identifies the amount of memory available and how to
access it, and retrieves information about system buses.
British thermal unit (BTU). A measurement of heat
produced in one hour.
broadcast. The transmission of data from a single
source to all devices in the fabric, regardless of zoning.
See also multicast and unicast.
BTU. See British thermal unit.
buffer-to-buffer credit. The number of frames that
can be transmitted to a directly-connected recipient or
within an arbitrated loop. Determined by the number of
receive buffers available. See also buffer-to-buffer flow
control.
Advertisement
Table of Contents
