Data Tech Institute Fundamentals Of Data Communications And Local Area Networks Seminar Workbook (1991)

276 Pages·1991·45.6 MB·English

by  Jay D. McGuire

FUNDAMENTALS
OF
DATA COMMUNICATIONS
AND
LOCAL AREA NETWORKS
I
=DATA-TECH
..... INSTITUTE
Lakeview Plaza• P.O. Box 2429 • Clifton, NJ 07015 • [phone]
DATA-TECH
INSTITUTE
429 Getty Avenue• P.O. Box 2429
Clifton, New Jersey 07015
SEMINAR_ ____L OCATJON ----DATE, _____I NSTRUCTOR ----
NAME ______________T ITLE ______________
COMPANY CITY _____________
1. FUNCTION (AREAS OF RESPONSIBILITY)
2. WHAT DO YOU EXPECT TO LEARN IN THIS SEMINAR?
3. PLEASE CHOOSE SEVERAL TOPICS FROM THE TABLE OF CONTENTS IN THE SEMINAR
WORKBOOK ANO PRIORITIZE REGARDING IMPORTANCE TO YOU TO BE EMPHASIZED
DURING THE SEMINAR.
4. WHY IS THIS TRAINING IMPORTANT TO YOU AND YOUR ORGANIZATION?
5. HOW WOULD YOU CATEGORIZE YOUR CURRENT UNDERSTANDING/KNOWLEDGE OF THE
SUBJECT?
FUNDAMENTALS
OF
DATA COMMUNICATIONS
AND
LOCAL AREA NETWORKS
Copyright 1991 Jay D. McGuire, 1st Edition
All Rights Reserved, Reproduction Prohibited
COURSE TOPICS
SECTION:
1. DATA COMMUNICATIONS CONCEPTS AND COMPONENTS
I 2. STORAGE OF DATA
3. TRANSMISSION RULES AND CONTROLS
4. WIRING AND DISTRIBUTION
5. PC LOCAL AREA NE1WORKS
6. COMMON NE1WORK STRUCTURES
7. LINKING LANS
8. LAN OPERATING SYSTEMS
9. LAN SERVERS
10. LAN MANAGEMENT
11. APPENDIX
Copyright 1991 Jay D. McGuire, 1st Edition
All Rights Reserved, Reproduction Prohibited
}
J
1
1
SECTION 1.0
}
DATA COMMUNICATIONS
CONCEPTS AND COMPONENTS
J
} Copyright 1991 Jay D. McGuire, 1st Edition
All Rights Reserved, Reproduction Prohibited
J
LOCAL AREA NETWORK EVOLUTION
MAINFRAME INTERACTIVE/TIME SHARING
BY THE 1960s, TIMESHARING ALLOWED
INTERACTION WITH THE COMPUTER
USING TELETYPEWRITER AND DATA
TRANSMISSION TECHNOLOGIES. THIS
ADVANCED TO INTERACTIVE PROGRAMS
THAT "TALKED" TO THE USER THROUGH
MORE ADVANCED TERMINALS.
J
BATCH PROCESSING
EARLY ON, IN THE 1950s USERS
BROUGHT THEIR JOBS TO THE MACHINE
TO BE RUN - THEY DID NOT DURING THE 1970s THE USE OF
INTERACT DIRECTLY WITH THE VERSATILE AND INEXPENSIVE MINI
PROGRAMS. NO DIRECT COMPUTERS GREW AS USERS DEMANDED
COMMUNICATIONS WAS COMPUTING POWER WHERE THE WORK
INVOLVED. WAS BEING PERFORMED. USERS BEGAN
TO SHARE FILES, PROGRAMS, STORAGE
AND DEVICES LEADING TO EARLY
DISTRIBUTED PROCESSING APPLICATIONS.
DISTRIBUTED PROCESSING
80% OF THE INFORMATION USED
COMES FROM WITHIN THE
ENVIRONMENT.
80%
80/20
RULE!
20%
1.01
NEED FOR INTEGRATED LOCAL COMMUNICATIONS
1980s SHOW RESULTS OF
0
YERY LARGE ~CALE INTEGRATION
(VLSI) TECHNOLOGY IN THE
PERSONAL COMPUTER.
ADVANTAGES IN NETWORKING IN
0
AND AROUND THE OFFICE·FOR
LOCAL:
DATA PROCESSING
DATABASE MANAGEMENT
PROCESS CONTROL
TYPESETTING
WORD PROCESSING
ELECTRONIC MAIL
SHARING ORj RESOURCES
STATEGIC VALUE OF NETWORKS
INFLUENCE (ECONOMIC)
INTEGRATION OF PROCESSES
INFORMATION AVAILABILITY
INTERCONNECTION/SHARING
INTERCOMMUNICATIONS
INTERRELATIONSHIPS
BUSINESS ARGUMENTS FOR LANS
INTERCONNECTION FLEXIBILITY
INTEGRATION SHARING RESOURCES
OBJECTIVES
CONTROL SUPLEMENTAL
0 IMPROVE PRODUCTIVITY ECONOMY VALUES (NON-
THROUGH MORE AUTOMATION UTILITY DATA USES)
OF ROUTINE FUNCTIONS. STABILITY STRATEGIC VALUE
0 IMPROVE MANAGEABILITY OF
INFORMATION THROUGH REDUCED DUPLICATION AND IMPROVED ACCESSIBILITY.
0 IMPROVE EMPLOYEE INTERACTION THROUGH SHARING OF INFORMATION.
0 REDUCE OR CONTROL COSTS BY USING COST EFFECTIVE COMMUNICATIONS.
~COOPERATIVE .PROCESSING BETWEEN PERSONAL COMPUTERS AND MAINFRAMES.
0 STANDARDIZE COMPUTER AND COMMUNICATIONS USAGE. 1.02
THE BASIC ELEMENTS
I.TRANSMITTER/RECEIVER TRANSMITTER/RECEIVER
' 2.TRANSMISSION MEDIA /
'
' T R /
' /
' /
R ' / T
'
/
' /
DTE ·. . . . . . . . . DTE
DATA TERMINAL EQUIPMENT • • • • • • •
3. "SIGNALS"
A-B-C-D-E-F-G-H-I-J-K-L-M-N-0-P
4. "CODES"
5. -"PRO-T·O -CO-LS4" --~--.
•
6 .• ARCHITECTURES"
]
...................................................................
BATCH DTE INTELLIGENT DTE INTERACTIVE DTE
PRINTER MICROCOMPUTER PERSONAL COMPUTER
RJE MINICOMPUTER "TERMINAL"
FILE TRANSFER MAINFRAME
3270
TAPE TRANSFER FRONT-END PROCESSOR
REPORT TRANSFER
TTY
VTlOO
ADM3
IBM 3101
IBM 2740
1.03
Analog and Digital Transmission
,:-
---l
Analog Signals
1 0 0 0 1 1 0
Digital Equipment Signals
J
ANALOG AND DIGITAL TRANSMISSION FACILITIES
There are three signalling methods that should be understood:
ANALOG, UNIPOLAR DIGITAL, and BIPOLAR DIGITAL.
]
An analog signal is a continuous wave of energy which carries
information on every part of the wave. A good example of analog
is sound waves passing through air. The same sound, if converted
to an equivalent electrical signal can be passed through a wire.
The original telephone network was analog, and a considerable
amount of it remains so today. Most of the diagrams in this book
will represent an analog electrical signal as a simple sine wave;
however, an actual voice, video, or modem-data signal is much
more complex.
The voice band analog facilities obtained from the telephone
company, both private line and dial-up, are limited in terms of
the electrical properties supported. For example, the range of
frequencies that are allowed to pass over these lines is between
300 hz (hertz or cycles per second) and 3300 hz. This yields a
BANDWIDTH of the difference or 3000 hz. There are about a dozen
more properties that describe how the line operates. These are
the specifications of the circuit and can be found in telephone
company technical specification manuals. Analog lines have no
data speed restrictions only electrical properties. They are
bandwidth restricted. Modems (described later) are used to send
data over these lines in accordance with these specifications.
Computers and other such equipment use on and off pulses of
electricity to communicate internally, with a binary 1 and 0
logically representing these on and off states. In such hardware
these are implemented by very short pulses at a level of about
zero vol ts ( logical O) or about 4. 0 vol ts ( logical 1) • This
format is called digital signalling, specifically using UNIPOLAR
digital format.
BIPOLAR digital format is better suited for transmission over
long distances. Bipolar means that some of the pulses alternate
between positive and negative voltages, or logical 1, and a zero
voltage level, or logical O. This is cal led ALTERNATE MARK
INVERSION signalling.
Telephone companies have offered digital transmission lines since
the early 1970s as an alternative to analog lines. AT&T's popular
DDS ( Dataphone Digital Service) and Tl CARRIERS are examples.
Digital transmission usually provides a much higher quality
transmission compared to analog. All signals must be regenerated
every mile or so due to line resistance. Digital repeaters in the
network filter out noise; however, the analog network uses
amplifiers which carry the noise to the end.
1.05