IBM 8265 Nways ATM Switch, Руководство пользователя

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communication systems, and associated equipment.
The ASCII set consists of control characters and
graphics characters. (A)
ARP. Address Resolution Protocol.
ASCII. American National Standard Code for
Information Interchange.
Asynchronous Transfer Mode (ATM). A transfer
mode in which the information is organized into cells. It
is asynchronous in the sense that the recurrence of
cells containing information from an individual user is
not necessarily periodic.
ATM. Asynchronous Transfer Mode.
ATM campus network. A union of privately-owned
ATM subsystems interconnected by network node
interfaces (PNNIs). See also
private network node
interface (PNNI).
ATM device. An end system that encapsulates data
into ATM cells and forwards them to the ATM
subsystem in the 8265 across an UNI interface.
ATM subnetwork. A set of ATM subsystems
interconnected by ATM interfaces (UNI, IISP, PNNI).
ATM subsystem. The ATM components in an ATM
switch.
attach. To make a device a part of a network logically.
Contrast with
connect, which implies physically
connecting a device to a network.
Authority and Format Identifier. One byte in an ATM
address.
available bit rate (ABR). ABR is an ATM layer service
category for which the limiting ATM layer transfer
characteristics provided by the network may change
subsequent to connection establishment. A flow control
mechanism is specified which supports several types of
feedback to control the source rate in response to
changing ATM layer transfer characteristics.
B
bandwidth. The bandwidth of a link designates the
information-carrying capacity of the link and is related to
the maximum bit rate that a link can support.
BER. Bit Error Rate.
bit error rate (BER). The ratio of the number of bits
experiencing error on a telecommunications link divided
by the number of bits sent over the link.
bits per second (bps). The rate at which bits are
transmitted per second. Contrast with
baud.
bridge. (1) An attaching device that connects two LAN
segments to allow the transfer of information from one
LAN segment to the other. A bridge may attach the LAN
segments directly by network adapters and software in
a single device, or may connect network adapters in
two separate devices through software and use of a
telecommunications link between the two adapters.
(2) A functional unit that connects two LANs that use
the same logical link control (LLC) procedures but may
use the same or different medium access control (MAC)
procedures. (T)
Contrast with gateway and router.
broadband. A frequency band divisible into several
narrower bands so that different kinds of transmissions
such as voice, video, and data transmission can occur
at the same time. Synonymous with
wideband.
broadcast. Simultaneous transmission of data to more
than one destination.
BUS. Broadcast and Unknown Server.
byte. (1) A string that consists of a number of bits,
treated as a unit, and representing a character. (T)
(2) A binary character operated upon as a unit and
usually shorter than a computer word. (A) (3) A string
that consists of a particular number of bits, usually 8,
that is treated as a unit, and that represents a
character. (4) A group of 8 adjacent binary digits that
represent one extended binary-coded decimal
interchange code (EBCDIC) character.
C
CBR. Constant Bit Rate.
CCITT. Comité Consultatif International Télégraphique
et Téléphonique. The International Telegraph and
Telephone Consultative Committee.
cell loss ratio (CLR). CLR is a negociated QoS
parameter and acceptable values are network-specific.
The objective is to minimize CLR provided the
end-system adapts the traffic to changing ATM layer
transfer characteristics. The CLR is defined for a
connection as Cells Lost/total Transmitted Cells. The
CLR parameter is the value of CLR that the network
agrees to offer as an objective over the lifetime of the
connection. It is expressed as an order of magnitude,
having a range of 10-1 to 10-15, and unspecified.
CLP. Cell Loss Priority.
CLR. Cell Loss Ratio.
configuration. (1) The arrangement of a computer
system or network as defined by the nature, number,
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IBM 8265: User's Guide