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GLOSSARY OF NETWORKING & TELECOM - PART 1
ONLINE LIBRARIES AND MICROCOMPUTERS
APRIL 1989
Msg. G0069  Category: NEWS & TRENDS

BRIEF GLOSSARY OF NETWORKING & TELECOMMUNICATIONS, PART 1

Telecommunications and networking of library computer systems has become a
major  trend.  It  is  virtually  impossible  to  read  about  any library
automation project without being bombarded with a  plethora of specialized
terminology, technical terms and acronyms. The scope of telecommunications
technology is immense and it is impossible to  provide a complete  list of
terms.However,  this brief glossary is intended  to offer non-technical
definitions to some commonly used terms.Even this brief  listing is too
lengthy to  fit in  one issue of  Online Libraries  and Microcomputers, so
that the definitions will be finished in the May 1989 issue.

Combining  Parts 1  and  2  of this  series  will  provide the information
manager with a very useful list of terms which may be useful to keep  as a
reference tool.


FILE SERVER -  A device on  a LAN that  provides central  storage for data
files.

FREQUENCY DIVISION MULTIPLEXING -  Divides the bandwidth of a data channel
into two or more subchannels.  See multiplexing.

FTAM -  File Transfer,  Access, and Management.  An application utility in
OSI that offers access to files on the network no matter what  file format
or host operating system.

FTP - File Transfer Protocol.  An application utility in TCP/IP.

FULL DUPLEX - Simultaneous independent transmission in two directions.

GATEWAY -  A device connecting between two dissimilar  networks  that adds
security,  flow  control,  and protocol conversion.It requires software

ACCESS CHANNELS -  Used to connect a local subscribers equipment to a long
distance network (often phone lines).

ACCUMASTER INTEGRATOR -  AT&T's UNIX-based system capable of automatically
uploading information from  other element management  systems via  the NMP
interface.

ACCUMASTER CONSOLIDATED  WORKSTATION (ACW)  -  An MS-DOS based system that
displays  a consolidated  network  view  by  providing  separate windowing
sessions to various AT&T EMSs.

ACOUSTIC COUPLER -  A  device into which one puts  a telephone  headset to
receive and transmit data.These are outmoded devices and are now rarely
sold although many are still in use with  microcomputers  and terminals in
homes.

ASYNCHRONOUS TRANSMISSION  -  Bytes  (characters)  of information are sent
with  special starting  bits and stop bits  which are identifiable  by the
sending and receiving devices.  Since characters can be sent one at a time
itrequires  aless  sophisticatedinterfacethana  synchronous
transmission.  Contrast with synchronous transmission.

AIX - a form of UNIX that operates on an IBM RT PC workstation.

ANALOG SIGNALS - Signals that vary continuously by amplitude or frequency.
Historically older transmission systems  have been analog  (e.g. the phone
service)  although most newer systems are digital in  nature. Compare with
digital signals.

ANSI - American National Standards Institute.

API  -  Application  Program Interface.This is  a program  which allows
applications  programs to talk  to communications software,  thus allowing
particular applications to be developed separately from communications.

APPC -  Advanced Program-to-Program Communication.  This API was developed
by  IBM to  allow its SNA networks  to  communicate without the need  of a
mainframe (also called LU6.2).

APPLICATION LAYER -  In the OSI model this is the 7th  layer (highest) and
is responsible for providing application programs for the end user.

ARCNET -  Datapoint has developed this low-cost LAN which  operates at 2.5
Mbps per second.

ARPANET -  The  Defense Advanced  Research Projects Agency  developed this
packet-switching  network  to  connect  computing  facilities  between the
federal government  and academia.TCP/IP  was originally  developed as a
part of the ARPANET project.

ATTENUATION  -  The  amount  by  which  an  electrical  signal  (including
microwave,  radio,  infrared, and light waves) weakens over distance as it
moves through the transmission media.

AUTO-DIAL -  The ability of a  computer to automatically dial  a telephone
number through a modem.

BACKBONE NETWORK -  a high speed network that links smaller or lower-speed
networks.

BANDWIDTH  -  The  range of  frequencies  that  can  be  transmitted  in a
communications  medium  (cable,  fiber,  radio,  etc.).The  higher  the
bandwidth, the more data that can be transmitted.

BASEBAND -  A single channel  network that transmits  digital signals (see
broadband).  An example is an Ethernet data link channel.

BAUD RATE - One signal element transmission per second. A baud and Bps are
not necessarily the same  although  they may be.With various modulation
techniques it  is  possible  to  encode more than  one bit of  data into a
single signal element.  Compare with Bps.

BITNET -  An electronic  mail  system  that  has been  established between
academic institutions through the auspices of EDUCOM.

Bps -  Bit Per Second.Transmission at one bit per second.  Compare with
baud rate.

BRIDGE - A device similar to a gateway except it connects similar networks
to one another and is  normally  self-programmed.  Bridges function at the
data link layer of the OSI model.

BROADBAND - A multiple channel network that carries information by carrier
waves  rather than directly as digital signals providing greater capacity.
Such backbones can carry data, radio, video and voice signals.

BSD -  Berkeley Software Distribution.  A version of UNIX developed by the
University of California at Berkeley.

BUS - In LANs this is a topology in which devices are attached to a single
strand of cable running between two points.

CARRIER  -  A signal on  a communications  media that does not  carry data
until  it  is  modified  in  some  way  (frequency  modulation,  amplitude
modulation).

CCITT-ComiteConsultatifInternationaledeTelegraphique  et
Telephonique.  An international body that develops standards.

CENTRAL SUPPORT UNIT  -  a  department  that  has the staff  and technical
expertise  to  provide  high-levelsupport  for  agiven  computer  or
communications system.

CHANNEL  CAPACITY  -  The  volume of data  that can be transmitted  over a
particular circuit or line.

CHEAPERNET - A name variation for Thin Ethernet.

CMIP -  Common  Management  Information  Protocol.An  OSI  standard for
network management.

CMIS - Common Management Information Services. An OSI standard for network
management. CMIS services are provided by CMIP.

COAX  -  Coaxial  cable is  a type  of  electrical  cable  which  has high
bandwidth,  low cost,  and low susceptibility to interference. However, it
is often difficult and expensive to install.

COMMON CARRIER - A government regulated private company that furnishes the
public with telecommunications services (e.g. phone companies).

CONCENTRATOR -  A device used to divide a data channel into two or more at
a lower speed.  Also called an asynchronous time division multiplexor.

CONNECTIVITY -  The ability of computer  devices to send and  receive data
with  one  another. However,  this  does  not  mean  that  two  devices
necessarily interoperate.

CORPORATION  FOR OPEN  SYSTEMS -  A group of computer  companies which are
developing  support for OSI-based  products  with  a  special  emphasis on
conformance testing.

CROSSTALK -  A leakage of a transmitted signal whena signal on one path
escapes onto another transmission path causing distortion.

CSMA/CD -  Carrier Sense Multiple Access with Collision  Detection.  A LAN
access method in which if data is being sent by one node and  it detects a
collision with other data,  it waits and then retransmits.  This method is
used in Ethernet.

DAA -  Data Access Arrangement.  Data communications equipment approved or
furnished by a common carrier that permits the attachment of a computer to
the common carrier network (usually phone line).

DARPA -  Defense Advanced Research Projects Agency.  A U.S. federal agency
which was responsible  for the development of the ARPANET  network and the
development of the TCP/IP protocols.

DATA CLOCK  -  The  signal  timing  element  which  is  necessary  for the
detection and decoding of a received signal.  This can be derived from the
incoming signals.

DATAGRAM  -  Data which is  transmitted as  an  isolated  entity  across a
network.This data does not need to be transmitted in order and  in this
type of  service any error checking  must be accomplished  by higher-layer
protocols or by the end user.

DATA LINK LAYER -  In the OSI model this is  layer 2  which represents the
physical medium.The IEEE splits this layer into two  sections:  LLC and
MAC.

DCNA -  Data Communication Network Architecture.  A communications network
developed by  IBM/Japan and  Nippon  Telegraph  and  Telephone Corporation
(NTT).

DECNET -  Digital Equipment Corporation's proprietary networking protocol.
Phase V which will be available in late 1989 will be OSI compliant.

DE FACTO STANDARD  -  An unofficial  standard  that is widely  used in the
industry because manufacturers choose to use it.

DE JURE STANDARD -  An official standard developed and adopted by a formal
standards making body such as IEEE, ANSI, CCITT, ISO, etc.

DEDICATED LINE -  A dedicated or leased line is a communication  line used
exclusively by one customer.In a  telephone leased line the  line often
does not pass through inter-exchange  switching equipment and the  line is
leased on a flat monthly fee regardless of how much data is transmitted.

DIGITAL SIGNALS -  Signals which consist of a series  of discrete elements
that have only one value at  a time.Digital transmission  systemsare
the heart of  most  modern  communication  systems.  Contrast  with analog
signals.

DIALNET  -  DIALOG  Information  Service'sproprietary  packet switching
network.

DNA -  Digital Network Architecture.The network architecture of Digital
Equipment Corporation of which DECnet is one implementation.

DNS -  Domain Name Server.A system that provides for the translation of
computer names to individual TCP/IP addresses.

DS1  -  An AT&T standard for the transmission of  high speed  data over T1
facilities.

DSU/CSU -  The DSU is a synchronous data  line  driver for short-distances
and a  CSU is an access  arrangement that  offers local-loop equalization,
protectionfrom  electricaltransients,self-testing,and  circuit
isolation.Thus a DSU/CSU is used to connect digital data  devices  to a
digital network. These devices are commonly bundled.

ELEMENT MANAGEMENT SYSTEM (EMS)  - A system that manages network elements.
This encompasses a host of devices such as modems, multiplexers and DSUs.

EMA -  Enterprise Management Architecture.  Digital Equipment Corporations
OSI-based  network  management  strategy.Like  UNMA,  EMA  provides for
multivendor network management using  interfaces based on OSI standards.

END-TO-END -  Communication between the source and destination nodes  on a
network.The transport layer handles end-to-end communications (contrast
with point-to-point).

ETHERNET -  A comprehensive baseband CSMA/CD  data communications standard
that  interconnects  computers  and  local  area  networks.The standard
version of  Ethernet  is defined by IEEE  in 802.3,  10BASE5.  A broadband
version is defined in  10BASE36;  Thin Ethernet using RG-58  coax cable is
defined in 10BASE2  and a version using twisted pair cable is specified in
10BASET.

FCC -  Federal Communications Commission.A U.S. Government agency which
regulates many aspects of communications.

FDDI -  Fiber Distributed Data Interface. This is ANSI standard X3T9.5 and
was developed to allow a cluster  of large computers  to  communicate with
each other and peripheral  devices with  100-Mbps bandwidth for  up to 500
station connections over  an optical fiber.  Dual rings can support  up to
1000 nodes.

FIBER  OPTIC CABLE -  A  transmission  medium  that  uses  light  waves to
transmit  data over glass fibers.  This medium  offers higher transmission
rates  and  better  security  than  electromagnetic  signals  but  is more
expensive.
programming and central management.

GOSIP -  Government OSI Profile.An OSI  based  standard  that  the U.S.
federal government has specified as an information processing standard for
government contracts.

HALF DUPLEX - A circuit that permits data communications in two directions
but not at the same time.

HANDSHAKING -  The exchange of predetermined signals for  the  purposes of
control between two devices.

HIGH  LEVEL DATA LINK CONTROL (HDLC)  -  A bit oriented data  link control
developed by ISO.

HUB - A central server in a star-configured network.

IBM CABLING SYSTEM - The specifications for the types of cables to be used
in connecting IBM products.

IBM  LAN SERVER  -  An IBM network operating system  built around  the LAN
Manager.

IBM PC LAN - An IBM network operating system built around MS-NET.

IBM TOKEN RING NETWORK -  A 2  Mbps LAN from IBM  which uses token-passing
techniques in a ring technology.Higher speed versions at 4  Mbps and 16
Mbps are also available (IEEE 802.5 is the standard).

IEE -  Institution  of  Electrical Engineers.A British-based society of
professional engineers.

IEEE - The Institute of Electrical and Electronic Engineers.  A U.S.-based
society of professional engineers.

IETF - Internet Engineering Task Force.  An organization which updates the
TCP/IP standards.

AN INTERNET - A set of interconnected, logically independent networks.

INTERNET -  The collection of networks that connect government, university
and commercial agencies (e.g. NSFNET, WestNet, etc.).

INTEROPERABILITY -  The  ability of  devices from  different  companies to
exchange information and  to understand and operate on  the data  that are
exchanged.

INTEROPERATOR  -  A hardware device  or software package  which implements
part of OSI standards and can work  with hardware or  software using other
parts of the OSI model.

IP ADDRESS - The address used to define the computer node number according
to the TCP/IP protocol.

ISDN- IntegratedServices Digital Network.  Adigitized
telecommunications network in which data  and voice would be  carried over
the same line using OSI standards.

ISO  -  The International Standards Organization.An international group
which promotes the development of computer (and other) standards.  The OSI
standards have been developed by this organization.

JABBER -  Noise on a network caused by the random transmission of data due
to a malfunction.

Kbps - Kilobits per second.

LAN - Local Area Network.  A cluster of PCs and other computer peripherals
inarelatively  smallarea  interconnected  forthepurpose  of
communications, file transfer and sharing of peripheral hardware.

LAN MANAGER -  A network operating system developed by  3Com and Microsoft
that takes advantage of the OS/2 operating system.  This term is also used
to refer to a person who is responsible  in an organization  for the daily
operations and maintenance of a LAN.

LAN SERVER - A proprietary version of IBM's LAN Manager.

LAT  -  Digital  Equipment  Corporation  has  developed  this  proprietary
protocol for terminal services which provides  communication for terminals
across an Ethernet LAN.

LAYER  -  The  conceptual  level  of  network  processing  functions.  For
example,  in OSI Reference Model the  network processing takes  place in 7
different  layers  from  the  physical  transmission  of  data  up  to the
applications layer.

LAYER INTERFACE -  A means of communication between the different adjacent
layers of the OSI model.

LEASED LINE - See Dedicated Line.

LINE DRIVERS -  A device which boosts a signal between its place of origin
and its destination.

LLC -  Logical Link Control.  The upper sublayer of the data link layer as
defined by IEEE 802.2.The LLC is common to  all IEEE  802 LAN standards
thus allowing different LANs to communicate in the  upper layers.  Compare
with MAC.

LOCAL AREA  DATA  TRANSPORT (LADT)  -  LADT is  based on  the  x.25 packet
switching protocol and allows data to be sent  over voice  lines at higher
frequencies than voice at speeds ranging from 1200 to 9600 bps.

LOCALTALK  -  Apple  Computer's  local area  network  using  the AppleTalk
network architecture and the network operating system called AppleShare.

LOCKING -  The ability to restrict or control access to files so that data
are not destroyed when more than one person tries to simultaneously modify
them.

LSP - Linked Systems Project. This is a development project by the Library
of Congress,  the  Research  Libraries Information Network,  OCLC, and the
Western Library Network to  link  their computer systems  to exchange MARC
authority records and MARC bibliographic records.

LSP  -Linked  SystemsProtocol. A  draftnational  standard  for
bibliographic  information  retrieval  being  developed  by  the  National
Information Standards Organization (NISO), Committee D. (Z39.50).

LU 6.2 - See APPC.

[GSM]

-----------------------------------------------------------------------------

GLOSSARY OF NETWORKING & TELECOM - PART 2
ONLINE LIBRARIES AND MICROCOMPUTERS
MAY 1989
Msg. G0079  Category: NEWS & TRENDS

  BRIEF GLOSSARY OF NETWORKING & TELECOMMUNICATIONS, PART 2

This is  part  2  of a telecommunications and networking glossary  for the
librarian  or  informationprofessional.Definitionsare  brief  and
non-technical although it may be necessary to refer to last month's part 1
when acronyms or jargon from last month's list are  used.  The combination
of parts 1  and 2  of this series may provide a useful list of terms  as a
reference tool.

MAC -  Media Access Control.  The lower sublayer of the data link layer as
defined by IEEE 802 LAN standards (see LLC).

routers, or gateways.

more follows -- press <RETURN> (Q to quit)SYNCHRONOUS TRANSMISSION -  A transmitting device sends special characters
(synch characters)  at the beginning of an entire message  and the message
must be sent in sequence.  Contrast with asynchronous transmission.

T1  - A digital communications facility developed by AT&T that operates at
a speed of 1.544 Mbps.

TCP/IP  -  Transmission Control Protocol/Internet  Protocol  is  a  set of
computer programs that enable communication between  similar or dissimilar
computers on  a network.Internet  Protocol  (IP)  is  the  standard for
sending basic units of data through an internet. TCP/IP enjoys wide vendor
MAP/TOP -  Manufacturing  Automation  Protocol/Technical  Office Protocol.
MAP is the,  OSI protocols and application utilities for the manufacturing
environment  which was originally  developed by  General Motors.TOP was
developed by Boeing Corporation but applies to the office environment.

MARC - MAchine Readable Cataloging.

Mbps - Megabits per second.

MICROWAVE  RADIO -  Microwave  data  links can easily  carry  up  to 6,000
telephone circuits per channel but must have  line-of-sight between towers
(every 25-30 miles).

MODEM -  A modulation/demodulation device which allows a digital device to
be connected to an analog transmission network and vice-versa.

MS-NET - A network operating systems developed by Microsoft which operates
with MS-DOS 3.1 or later.

MULTIDROP LINE - A single communications line with several interconnecting
stations.  Using this type of line often requires a polling mechanism.

MULTIPATH DISTORTION -  When signals arrive at slightly different times at
a receiver due to different data paths.

MULTIPLEXING -  A method for transmitting two or more separate channels of
data  on  a  singlefacility. Three  techniques  are  commonly  used:
frequency-division multiplexing  (FDM);  time-division multiplexing (TDM);
and statistical multiplexing.

MULTITASKING -  The ability to run  more than one program at  a time  on a
computer.

NACO  -  Name Authority Cooperative.Name  authority  records  are being
transmitted via the Linked Systems Project.

NAMED PIPES  -  An API for LAN Manager which allows  the transfer  of data
from one application to another.

NCCF -  Network Communication Control Facility.IBM's host-based network
management  software  that  provides  the operator  interface  and network
logging facilities.

NETBIOS -  An API developed for IBM  networks  and  is  widely  used  as a
standard interface to communications protocols.

NETVIEW -  The network management product from  IBM for its  SNA networks.
Data from non-SNA environments can be obtained through NetView/PC.

NETWARE - Novell, Inc.'s network operating system.

NETWORK  FILE  SYSTEM  (NFS)  -  Sun Microsystems, Inc. has developed this
network  service that allows transparent access to  files located anywhere
on the system.

NETWORK LAYER -  In the OSI Reference  Model  this  is  layer  3  which is
responsible for routing data across the network.

NETWORK  MANAGEMENT  PROTOCOL  (NMP)  -  The  protocol  used  in  UNMA  to
communicate information from  various vendors'  element management systems
to the Accumaster Integrating System.  NMP is full compliant with OSI.

NETWORK OPERATING SYSTEM (NOS)  -  The software that manages file sharing,
security, electronic mail, methods for interfacing with different computer
networks and any other resources of a network.

NETWORK SERVER -  a central computing device on the LAN that  provides for
file storage, printing operations, modem connection, etc.

NODE - a computer or single PC on a network.

NPDA  -Network  Problem  Determination  Application-  IBM's  network
management product that uses a series of panels to provide operators  with
information needed to perform problem determination and resolution.

OCLC - Online Computer Library Center.

OPEN SOFTWARE FOUNDATION -  A group of computer firms which  is working on
developing a standardized UNIX operating system.

OPEN SYSTEM -  A computing  system that uses  publicly available standards
for  its  architecture.This  allows  easy  development  of  third party
products as well as easier networking with this type of system.

OPERATING SYSTEM -  Software which interfaces the physical resources  of a
computer and an applications program.

OPTICAL FIBERS - see FIBER OPTIC CABLE.

OSAK -  OSI Applications Kernel.  A full implementation of the OSI Session
Layer  in  DECnet  phase V that  provides  an API that manages  the dialog
between an applications program on an OSI network.

OS/2  -  An operating system developed by Microsoft for IBM  and  its PS/2
line of computers.

OSI  -  Open Systems Interconnection.The  general name  used  for ISO's
effort  to standardize computer-to-computer communications.The standard
has a seven  layer model for communications  and sections  of the protocol
are still in  development.The OSI model  defines an open system  as one
that obeys OSI standards in  it  communications with other  systems.  This
contrasts with  proprietary  architectures  (such as IBM's  SNA) which are
designed to support one vendor's equipment.

OSI/NETWORK MANAGEMENT FORUM  -  A group of companies which is  focused on
supporting network management standards for the OSI model.

PACKET -  A unit of data which is transmitted at the network layer.  It is
also commonly used to denote an envelope  of data bundled  with addressing
information for transmission through a network.

PACKET  RADIO -  A communications technique in  which packets of  data are
sent via radio waves.

PACKET-SWITCHING  -  A  method  in  data communications in  which data are
divided  into  packets and are routed  to  the final  destination  via the
fastest route.  The final destination node is responsible for reassembling
the packets into the proper order.

PARALLEL TRANSMISSION -  The sending of several bits (making up a byte) at
a time  from  a computer  to  an  external  device.Contrast with serial
transmission.

PBX - Private Branch Exchange. A private switching system often located on
a customer's premises.

PHYSICAL LAYER - In the OSI model this is layer one and is responsible for
the actual sending of the data on the transmission medium.

POINT-TO-POINT -  Data communications that  occurs between two  nodes on a
network without passing through any intermediate nodes.  The network layer
handles this type of communications.

POLLING - A means of controlling terminals on a multidrop line.  Thus each
terminal  is  sequentially  queried to determine  if any data is  ready to
send.

POSIX - A type of UNIX using IEEE standards.

PRESENTATION LAYER - In the OSI model this is layer six and is responsible
for sending data in proper format between the application  program and the
lower layers.

PROPRIETARY  STANDARD -  A standard developed  or owned by one  company or
group.  Some companies license  their proprietary products  to third party
developers.

PROTOCOL -  A collection of rules that control the exchange of information
between the same layers in different nodes on a network.

PROTOCOL STACK (PROTOCOL SUITE) - A set of related protocols.  This phrase
is often used when referring to  the protocols as  implementing the layers
of the OSI model.

PULSE CODE MODULATION (PCM) - Transmission of information by modulation of
an intermittent carrier.Pulse width,  count,  phase or amplitude may be
varied.

REDIRECTOR -  Software that reroutes network commands away from MS-DOS and
onto the network in MS-NET.

REPEATER -  A device which boosts an electrical signal thus increasing the
transmission distance possible.

RING -  A network topology  in which each node  is connected  in series to
form a loop (contrast with BUS and STAR).

RLIN - Research Library Information Network.

ROUTER - A device which interconnects two networks.  These function at the
network layer of OSI and can determine the most  efficient route  by which
to send data.

RS-232C - A standard developed by EIA (Electronics Industries Association)
which specifies a low-speed interface between computer  equipment such  as
modems or printers and computers.

SAA  -SystemsApplicationArchitecture. IBM  products  use  this
architecture to provide a  common a programming interface,  a common means
of  user  access  and  common  communications  support  for  IBM operating
systems.

SDLC -  Synchronous Data Link Control.  Used by IBM under the SNA with IBM
3270 family of terminals.

SERIAL TRANSMISSION -  The sending of data sequentially one bit at  a time
over a single channel.Modems for microcomputers usually operate in this
mode.

SERVER - See File Server.

SESSION LAYER - In the OSI model this is layer five and is responsible for
directing user commands to a local operating system or to the network.

SHORT HAUL TRANSMISSION DEVICES -  This transmission medium  is commonly 2
or  4  strand twisted pair  wire  which  allows  transmission  from  a few
thousand feet to a few miles.  The range depends on transmission rate, the
transmission mode, and the transmitting and receiving devices.

SIGNAL  TO  NOISE RATIO  -  The  amount  by  which  a  signal  exceeds its
underlying noise.

SMFA -  Specific Management Functional Area.In the OSI model  this will
define individual network management services.

SMTP - Simple Mail Transfer Protocol.  An application utility in TCP/IP.

SNA  -SystemsNetworkArchitecture. IBM'sproprietary  network
architecture for communicating with IBM and non-IBM computers.

SNI -  Standard Network Interconnection.The mechanism that supports the
intersystem communication for the Linked Systems Project.It follows OSI
standards.

SNMP -  Simple Network Management  Protocol.A TCP/IP network management
protocol.

SOCKETS  -  A program which  interfaces TCP/IP with  Berkeley's version of
UNIX.

STAR -  A network topology in which a central device  (Hub)  has all other
devices in the network directly linked to it.  It is also possible to have
several hubs linked forming a hierarchy.

STARLAN - A local area network operating in a star or daisy chain topology
and was originally developed by AT&T.It is now part  of  the IEEE 802.3
standard.

STATISTICAL MULTIPLEXING  (STAT MUX)  -  A multiplexing technique in which
channel  capacity  is  allocated based on  the transmission  of productive
traffic.

STORE AND FORWARD NETWORKS  -  A network in which messages  are collected,
packaged, transmitted, unpackaged and delivered by a network processor.

STREAMS - UNIX v.3's framework for network communications.

SUBNET  -  A network  that is connected to  a larger  network via bridges,
support  particularly  among  universities  and  the  federal  government.
However,  TCP/IP is not compliant with the emerging OSI standard which  is
universally expected  to  be the  standard of the future.Thus migration
paths will need to be developed to move from one protocol to the other.

TELNET - An software application utility for TCP/IP that provides terminal
emulation.

TELENET - A commercial packet switching network.

TERMINAL EMULATION  PROGRAM  -  Software  which  allows  microcomputers to
emulate different terminal types.  Different terminal emulations are often
incorporated into popular communications packages.

TERMINAL SERVER - A device that connects terminals (or other equipment) to
a local area network.A server lets  users of terminals  connect to more
than one computer.

THIN  ETHERNET  -  A  version of Ethernet that  operates on an  RG-58 coax
cable.

3+ - 3Com's popular network operating system.

TIME DIVISION  MULTIPLEXING  -  Divides a data channel by  time to support
several subchannels.  See multiplexing.

TLI - Transport Layer Interface. UNIX System 5 Release 3 incorporates this
application program interface.

TOKEN - A method of passing data bits in a network.

TOKEN BUS - A local area network that uses the token passing method with a
bus topology.The IEEE 802.4  is the standard for this topology  and MAP
specifies token bus as the LAN portion of its protocol stack.

TOKEN PASSING - A method in which a token is passed around the network and
is available to each  station in the  network.Only the station that has
the token can transmit on the network (contrast with CSMA/CD)

TOKEN RING -  A local area network that uses the token passing method as a
ring topology.

TOP - See MAP/TOP.

TOPOLOGY  -  The physical layout  of a network.It refers to  the way in
which the transmission media are interconnected to form a complete system.
In LANs the major methods are star, bus and ring.

TP4 - The transport layer protocol in OSI.

TRANSCEIVER -  A device that both transmits and receives.In an Ethernet
system  this  unit  provides  a physical  and electrical  interface to the
network  cable  and  monitors  the  cable  for  activity  toavoid  data
collisions.  This device is also called a media access unit.

TRANSPORT LAYER - In OSI this is layer four and is responsible for keeping
end-to-end communications.

TWISTED PAIR -  Cabling which has two wires wrapped around each other.  It
is most commonly used in  phone systems but is  a low-cost  medium for LAN
connections or directly connecting workstations to a host computer.

TYMNET - A commercial packet switching network.

ULTRIX - A version of UNIX developed by Digital Equipment Corporation.

UNIX -  One  of  the most  popular  multiuser  and  multitasking operating
systems which was originally developed by AT&T.There are many different
versions of  this  operating system and  it is easily  ported to different
kinds of computers.

UNMA -  Unified  Network  Management  Architecture.A  proprietary three
tiered  architecture  for network management  developed by AT&T.  It is an
open architecture which employs interfaces based on OSI standards.

VALUE  ADDED NETWORKS  (VAN)  -  These are usually developed  by companies
which lease  common  carrier  phone  lines  and  develop  different tariff
structures.  Examples in the United States would be Telenet and Tymnet.

VAX FTAM -  In DECnet Phase V,  this file transfer,  access and management
protocol allows file management and transfers to OSI compliant systems.

VINES - VIrtual NEtworking System.  A proprietary network operating system
developed by Banyan Systems, Inc.

VIRTUAL CIRCUIT - A communications link that gives the user the impression
that a dedicated line exists between the remote device and the host.  This
impression is  due to  the fact  that data are processed in  the  order in
which it was sent (just as with a real circuit).  Contrast datagram.

VIRTUAL TERMINAL - A remote terminal emulation utility program for OSI.

VOTS -  VAX OSI Transport Service.  Provides OSI transport layer functions
in DECnet phase V and supports interworking among different subnetworks by
using  the  Internet  Protocol,which  provides  Connectionless  Network
Services over local  area networks and X.25 wide area networks.

WAN -  Wide Area Network.  A communications network that spans large areas
(hundreds  or  thousands  of  miles)  by  using  telecommunications  lines
provided by a common carrier (e.g. the phone company).

WATS -  Wide Area  Telecommunications Service.Allows phone customers to
make long-distance calls and have them billed on a bulk basis  rather than
one-by-one.

WAVE DIVISION MULTIPLEXING - Transmitting two or more separate channels of
data over an optical fiber using different wavelengths of light.

WAVEGUIDES  -  These  microwave pipes can be  used  to  transmit microwave
signals and are often used  to  transmit  microwave  signals  up  and down
microwave antenna towers.

WLN - Western Library Network.

WORKSTATION  -  A  device,  often  a  microcomputer,  which  serves  as an
interface between a user and  a file server or host computer.

X.25  -  A CCITT  standard that defines a protocol  for gaining  access to
public packet switching networks.

X.400  -  A CCITT standard  for electronic mail.  In OSI this would  be an
application utility.

XENIX  -A  version  of  UNIX  developed  forthe  IBM  ATclass  of
microcomputers.

XNS -  Xerox Network Systems.  A local area network architecture developed
by  Xerox  Corporation  but  never  became  popular  as  a  communications
standard.  However, proprietary variations of this architecture are widely
used.
[GSM]