Table Of ContentCommunications Technology Guide for Business
Preface
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Part I: Technology
Chapter 1: Communication Services and Networks
Chapter 2: Communication Principles
Chapter 3: PBXs
Chapter 4: Local Area Networks
Chapter 5: The Telephone Network
Chapter 6: ISDN
Chapter 7: Public Data Networks
Chapter 8: The Internet
Chapter 9: Mobile Communication
Chapter 10: Value-Added Services
Chapter 11: Communication Equipment
Chapter 12: LAN Interconnect
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Part II: Managing Business Solutions
Chapter 13: A Business Approach to Communication
Chapter 14: Developing a Communication Solution
Chapter 15: Supplier Selection and Management
Chapter 16: Tariffs
Glossary
Communications Technology Guide for Business
by Richard Downey, Sean Boland and Philip Walsh ISBN: 0890068275
| Artech House © 1998 , 408 pages
Communications Technology Guide for Business
Richard Downey
Seán Boland
Philip Walsh
Cover design by Deborah Dutton and Joseph Sherman Design
Microsoft and Lotus Freelance clip art is used in this book, with permission.
©1998 ARTECH HOUSE,INC.
685 Canton Street
Norwood, MA 02062
All rights reserved. Printed and bound in the United States of America. No part of this book may be
reproduced or utilized in any form or by any means, electronic or mechanical, including
photocopying, recording, or by any information storage and retrieval system, without permission in
writing from the author
All terms mentioned in this book that are known to be trademarks or service marks have been
appropriately capitalized. Artech House cannot attest to the accuracy of this information. Use of a
term in this book should not be regarded as affecting the validity of any trademark or service mark.
International Standard Book Number: 0-89006-827-5
Library of Congress Catalog Card Number: 97-32245
10 9 8 7 6 5 4 3 2 1
Preface
Overview
In today’s telecommunications industry, there is a somewhat bewildering set of technologies and
services available. Some of these are destined to change the world we live in, others have
enormous significance in niche markets, while others will inevitably be relegated to the status of
“old technology” and disappear slowly or rapidly.
Most business managers already sense that they could be making better use of communications
technology. They have seen and heard examples of success elsewhere, but they do not feel
qualified to make a plan for their own business. Employing a consultant or inhouse expert to make
a plan is one option. However, ideally the manager should be taking an active part in the planning
process and must at least understand what the experts are proposing.
In business, there is often an inertia towards the adoption of new technologies. Delayed
implementation contains an implicit risk of a missed, or at least delayed, opportunity. Many want
evidence of concrete success stories and monitor how others get on with a technology. Others
wait to allow time for any initial problems to be solved and for costs to fall. However, often the
reason for not implementing new technologies is a lack of understanding of their capabilities and
the opportunities that they create. In today’s world of constant change and continuous
improvement, unwarranted delays may well leave a business at a significant disadvantage.
The growth of the Internet is probably the best known example of the way communications
technology is creating new opportunities for business. Many have already embraced it
wholeheartedly. Others, however, have been slower or less informed in their approach to this
technology. If this is the case for such a visible technology, it is not surprising that the situation is
much worse for technologies that do not attract such media hype. Video conferencing, for
example, has great potential to save time and money and is already a relatively mature
technology, but the number of adopters is still quite low.
The situation is even more confused when it comes to distinguishing between such services as
X.25, ISDN, and frame relay. Some of the newer services have the potential to significantly reduce
communication expenditure in certain instances, but this may go unrecognized for quite some time
if some basic knowledge is not available inhouse.
Security is an issue that some tend to overlook in their eagerness to gain some business
advantage, while others are paralyzed into doing nothing for fear of major problems. An
understanding of security issues will help to avoid either extreme.
Aim of This Book
This book aims to give managers with communication responsibilities and indeed general business
managers a broad view of the technologies available today, so they can deal knowledgeably with
consultants, suppliers, and inhouse experts and make informed choices. We expect our primary
readership to include business managers and financial personnel. With this in mind, we believe
that this will be a useful text for many business courses, particularly those that include modules on
the application of technology to business. We also envisage that this book will provide a useful
introduction/overview for communication managers, IT managers, and telecommunication
engineers. Finally, we expect sales and marketing personnel and many others who work in the
telecommunications industry to benefit from this book.
The basic principles are explained so that the reader is better able to distinguish between
technologies. Typical applications are described and cost issues are discussed. The inevitable
limitations—so often missing from sales literature—are also explained. Security issues are
discussed so that the reader will know what parts of a communication system are vulnerable to
attack and can arrange appropriate protection.
The development of appropriate communication solutions and their subsequent implementation
are also discussed. A business-planning process is described, followed by recommendations on
developing a solution, procurement, and supplier management. The impact of tariffs on any
proposed solution is also addressed. We strongly recommend that readers who are more
technically minded do not skip over this part of the book, as it introduces topics that are sadly
missing from many communication projects driven primarily by technical considerations.
This book has grown out of a seminar entitled “Business Communications” developed and
delivered by the authors in conjunction with Telecom Ireland International, the contracting and
consultancy wing of Telecom Eireann. Through these seminars, the authors have gained an
insight into the material of most interest to an audience of business managers and communication
managers. The opinions expressed in the book are those of the authors and not necessarily those
of Telecom Eireann.
Telecom Ireland International specializes in providing training, consultancy, and operations support
in the telecommunications industry and can be contacted by sending email to [email protected].
Reading Guidelines
This book has been arranged to facilitate the reader who wishes to read it from start to finish. We
realize that such a reading plan will not suit many busy readers, and thus we have tried to write
individual chapters in such a way that they could be read on their own aided by a few cross-
references and glossary lookups. In order to gain the most from this approach we recommend that
such a reader would first familiarize themselves with the contents of Chapter 2. Furthermore we
suggest that a newcomer to communications technology might also read the first few pages of
each chapter in the first part of the book in order to get a better overview of things.
The glossary has been compiled with the “chapter at a time” reading plan very much in mind. We
have limited the contents of the glossary to terms which crop up in multiple chapters. Thus, for
example, if you were to launch into the book at Chapter 6 on ISDN, you would find ISDN
terminology explained within the chapter, and most general telephony jargon that appears
unexplained would be found in the glossary. Much of the ISDN-specific terminology is not,
however, included in the glossary. If necessary these terms can be found using the index.
The references at the end of the chapters contain many web references. It is the nature of the web
that these references will no longer be valid in the future. Where this is the case it may still be
possible to find the reference through the use of a general search engine such as AltaVista.
Alternatively, you could find the home page of the particular site and browse from there to find the
article. You might also check if the particular site has its own search engine. This way you may find
an update to the original article. You can find the home page of most sites by typing in the web
reference ignoring everything after the domain name (e.g., typing http://www.domainname.com
instead of, say, http://www.domainname.com/bla/bla/bla).
In many of the diagrams we represent networks using a cloud symbol. Newcomers may find this
confusing. The cloud is simply used to represent a more or less complex network in the same way
as a box might be used to represent a complex piece of equipment. This is quite a standard
approach, which some jokingly refer to as cloud technology.
Acknowledgments
First, we would like to thank Paul Thornton, LAN administrator, pricing division, Telecom Eireann,
who wrote Chapter 12 on LAN interconnection and helped a lot with the material on LANs in
Chapter 4. We also appreciate all at Artech House for their patience and perseverence with the
project. A special word of thanks to the Artech House technical reviewer for his helpful and
pertinent comments and his assistance in giving a U.S. slant on the subjects and to Glenn Powell,
vice president of Valuecom for his help in reviewing the chapter on tariffs. We also wish to thank
Telecom Eireann for their support.
We are grateful to those who checked our work for relevance and readability, including Luis
Lasalla, Barry O’Grady, Daniel Dorn, Carlo Papa, Juan Martinez, James Hurley, John Cahir, Aidan
Scanlon, and Pat Feenan. We are also glad to acknowledge the technical input received from the
staff of Telecom Eireann, including Sean Abraham, Tim Flynn, Paul Dervan, Denis Curran, Derik
Frier, Vincent Hendrick, Liam O’Connor, Pamela Harisson, Pat Duggan, Philip Maguire, Charlie
Tone, Neil O’Sullivan, Paul Grealy, and all those who contributed indirectly by sharing their
knowledge and experience with us over the years.
Our thanks to Peter Cullen at Trinity College Dublin; Donal McGuinness at Lake Electronics; Chris
Coughlan, marketing and strategic planning manager, Digital Equipment International; and Tom
Quinn, regional sales manager at Tellabs. Next, we thank the ever-helpful Mary O’Dowd, librarian
of the Telecom Eireann corporate library, who helped us so much in our search for relevant
material, and Eddie Cahill, who provided much-needed encouragement during the initial
development of the “Business Communications” seminar.
Finally, we thank Mary Boland, Antoinette Walsh, and all the members of our families who have
borne with us patiently and offered us much needed support and encouragement. Our children,
Amy and Ruth Boland and Steven and Brandon Walsh deserve special mention. All will be happy
that the project is finished, and Amy and Ruth can, at last, stop asking, “When will daddy be
finished with ‘the book’?”
About the Authors
Richard Downey joined the Irish Department of Post and Telegraphs* in 1981 as an executive
engineer in the switching department, where he worked on traffic engineering, network
synchronization, and exchange procurement. In 1988 he transferred to the technical training
division, where he designed and delivered a range of courses on PCs and LANs in conjunction
with managing the division’s LAN and information systems. This was followed by the development
and delivery of technical induction training for new telecommunication engineers in Telecom
Eireann, data communication training for internal and external customers, and the design of
documentation standards for the training division. He has a bachelor’s degree in electrical
engineering from the University of Dublin. Mr. Downey can be reached at [email protected].
Seán Boland joined the Irish Department of Post and Telegraphs* in 1977 as a trainee technician.
Af h lifi d h k d h i i i hi d i i i
After he qualified, he worked as a technician on switching systems and customer circuit testing.
During this time, he continued his studies privately and received the full technological certificate
from the City and Guilds of London Institute. He was subsequently awarded a scholarship by
Telecom Eireann and, in 1988, obtained an honors degree in electronic engineering from the
University of Dublin.
His initial appointment was as executive engineer in Telecom Eireann’s technical training division.
During this period, he designed and delivered a wide range of courses dealing with
communications technology. He also developed a close working relationship with Telecom
Eireann’s consultancy wing. This led to the development of many customized courses for external
clients from many backgrounds and industries. It also lead to the development of the
“Communications Technology” seminar, which was the inspiration for this book.
Seán subsequently moved to the Network and Group Technology Directorate within Telecom
Eireann. His current responsibilities include evaluation of new technologies, network development,
and technical support. Seán also has wide experience as a lecturer and examiner in technical
subjects. He has been an open learning tutor with the University of Limerick, and he currently
lectures in the Dublin Institute of Technology and the University of Dublin. His email address is
[email protected].
Philip Walsh currently works with Ericsson Expertise in Dun Laoghaire, Ireland. He joined the Irish
Department of Post and Telegraphs* as a trainee technician in 1980. In 1983 he was awarded a
scholarship by the department to study electronic engineering in the Dublin Institute of Technology.
On graduating in 1987 with an honors degree, he was appointed as an executive engineer in the
technical training division in Telecom Eireann. Between 1987 and 1997, he was responsible for
technology-based training, course design, PC applications training, external plant training, and
switching training at various times within Telecom Eireann. In May 1997, he joined Ericsson
Systems Expertise as an operations and maintenance consultant specializing in intelligent
networks. Mr. Walsh can be reached at [email protected].
Chapter 1: Communication Services and Networks
1.1 Introduction
Communication services, and their associated communication infrastructure, play a vital role in
today’s business environment. The list of potential applications is continually growing, and
businesses that exploit them to their fullest extent can gain a significant competitive advantage
over their rivals. Businesses that do it well are reaping significant benefits when the specified
solutions are finally implemented. They are gaining new customers, accessing new markets, and
generally thriving—often at the expense of their less communication-aware competitors.
Current and emerging technologies now enable even the smallest businesses to take advantage of
a wide range of communication services. This means that, to stay competitive in this environment,
many businesses will have to become significantly more “communication aware” than heretofore.
They will have to make greater use of communications technology as an everyday business tool
and do so in an efficient and innovative manner.
Although this book is primarily about communications technology, the authors are fully aware that a
distinct dividing line between communications technology and information technology (IT) no longer
exists. Throughout the book the term information and communication technologies (ICT) is used as
a general term when dealing with information electronically. The term communications technologyis
used when we wish to highlight the communication-specific aspect of any solution.
1.2 Function of Communications Technology
The basic function of communications technology is to facilitate the transfer of information between
computer systems or end users. Put another way, communication systems provide connectivity.
Ideally this connectivity should be instantaneous—and universally available regardless of time,
distance, or location. It should be transparent to all applications and all types of information, with
no regional, national, or international variations. In this utopian world, communication networks
would be regarded as just another utility analogous to gas or electricity networks. In practice, many
constraints—legal, economic, regulatory, and technological—prohibit such universal connectivity.
1.2.1 Types of Connectivity
Connectivity can be either permanent (as in the case of a fixed communication link) or temporary
(such as a phone call).
Permanent connectivity is used where:
•Information must be transferred on a continuous or near-continuous basis (e.g., a video
surveillance link);
•Immediate connectivity must be available when required (e.g., a link from a financial services
company to an information provider);
•It is more cost-effective than temporary connectivity (e.g., between multiple sites belonging to the
same business).
Temporary connectivity is used where:
•Information is only transferred on an occasional or intermittent basis (e.g., between a retailer and
its suppliers);
•Permanent connectivity is too expensive (e.g., it cannot be afforded or cannot be justified);
•It is a particular requirement of the application (e.g., permanent connectivity cannot be provided
between all users of the public telephone network).
1.2.2 Cost of Connectivity
Communication services are a significant cost to any business. The good news is that these costs
are still falling in most countries. It is also becoming easier to measure communication costs more
accurately. This allows costs be apportioned according to usage or particular requirements
specified. In some businesses it also facilitates passing on communication charges to clients.
However, it is likely that cost constraints will continue to limit how businesses use communications
technology, at least for the moment. Common compromises include restricting the amount of
information transferred or delaying the transfer of information until reduced rate tariffs apply.
Connectivity costs are related to the following:
•Quantity of information: the greater the quantity of information the greater the cost;
•Distances involved: the cost of connectivity increases with distance;
•Mobility requirements: the cost of connectivity is significantly greater for mobile applications;
•Time sensitivity: connectivity is less expensive during off-peak periods;
•Duration: temporary connections are cheaper than permanent connections if the connectivity is
only required for short periods.
1.2.3 Scope of Connectivity
Connectivity may be required within a confined geographic area (e.g., a single site) or may be
required over a geographically dispersed area. Means of providing single site connectivity include
private branch exchanges (PBXs) for voice and local area networks (LANs) for multiple types of
information. These options are covered in Chapters 3 and 4, respectively. Single-site
communication solutions can be completely controlled by a business and, optionally, owned by it.
In addition, due to the short distances involved, high-performance networks can often be installed
cost effectively.
Numerous options are available for intersite connectivity and many of these are discussed in
Chapters 5 through 9. Where temporary connectivity is required, a number of public networks
(such as the public telephone network) are available. These are often referred to as wide area
networks (WANs). They can be further characterized as being either national or international.
Where connectivity is required on a frequent or continuous basis a private WAN can also be used.
Private WANs are expensive to install and operate, more particularly due to the high cost of the
intersite communication links. This means that many businesses cannot afford them. Fewer still can
afford to run information-intensive applications, such as multimedia, at their full potential over
WANs. International WANs represent an even greater challenge as multiple suppliers of equipment
and communication links may be required. Service integrators are often used for such networks
because of their knowledge as to what can and cannot be done in the different countries.
