Customer Reviews

ADSL and DSL Technologies (Standards & Protocols)

5 star:		(4)
4 star:		(3)
3 star:		(3)
2 star:		(1)
1 star:		(1)

 

 

Writing a popular book about xDSL technology is a daunting task, but one that Walter Goralski largely accomplishes in his book "ADSL and DSL technologies." The book begins with a global view of the US telecommunications network, how the Internet is challenging this network, and what technologies are being developed to address the problems. This world view does an excellent job of placing xDSL technologies in perspective: they are solutions to digital data transport over portions of a telecommunications network designed specifically for analog voice traffic.

The author has provide an excellent summary of how the American telephone network began, how it evolved, the various regulatory actions along the way, and the current state of affairs. For example, many people familiar with load coils and bridge taps know they can cause problems for xDSL technologies. Goralski explains how these devices got into the network in the first place, and the specific problems they pose for digital high-speed technologies. As part of this discussion the author describes the first analog systems, later digital systems, multiplexing and trunk topologies, different switching technologies (packet and circuit) and the first wave of digital services such as ISDN.

After a brief discussion of modems, the author launches into the main subject, which is the xDSL family of products and technology. He gives a brief high-level descriptions of HDSL, SDSL, RADSL, CDSL, IDSL, ADSL, and VDSL. Up to this point the number of acronyms is relatively manageable, but once he begins discussing xDSL in earnest the acronyms emerge exponentially. Fortunately, Goralski has a list of about 250 acronyms in the back of the book. This list is especially useful later in the book where the author uses them with abandon. Though extensive, the list is not complete. For example, the acronyms PCM and STU are not included. Of course, the author says there is "really no such thing as an `STU,' at least not as a standard device." This only adds to the confusion of the use of such an acronym, and contributes to the "acronym overload" one often feels when reading this book.

After the brief introduction to the xDSL family, the author devotes a full chapter each to HDSL and then to ADSL. After this, the book deals almost exclusively with ADSL-related issues (except for a chapter on VDSL at the back of the book).

I was disappointed the author spent so little time describing the digital coding techniques that are so important for DSL technologies. Except for a brief mention of QAM, the author leaves his audience almost entirely in the dark as to how the digital codes work, and what are their individual strengths and weaknesses.

The author goes into considerable detail (more than any other individual topic) describing the ADSL architecture and interface systems. Chapter nine, dealing with ADSL interfaces, is confusing and would benefit from more diagrams. Several subjects are discussed without proper introduction, leading to questions people might ask if they are not already familiar with the terminology. Additional topics in the book's midsection include descriptions of transport classes, bearer channels, frames, super frames, frame structure, interleaved data, and overhead. The author also provides considerable high-level detail about various configurations in which ADSL can be deployed.

The book ends with three of its most important chapters. Chapter 13 describes migration scenarios from the various derivatives of xDSL to ADSL, and from ADSL to VDSL. Chapter 14 describes VDSL in more detail, since the author apparently concludes VDSL will be the ultimate mechanism by which telecommunications companies will provide truly broadband services. Chapter 15 finishes with a discussion about the major outstanding issues for DSL. These last chapters are especially useful for global thinking and positioning.

Goralski discusses some market issues for the deployment of ADSL, but most of the book centers on technical topics. The author clearly favors xDSL technologies, with the apparent conclusion it will win the day over cable modems. It would be useful, however, to see more detailed analysis in this area, especially regarding cost for deployment. Though Internet access (e.g. as offered via xDSL) is important, Internet access alone will be unable to compete against true broadband services offering video on demand in addition to fast Internet access. Goralski seems to recognize this when he discusses VDSL, but even here he fails to address economic issues and whether VDSL can compete on price with cable modems.

Goralski has a clear, readable style, and the book has many figures that greatly help in assimilating ideas. On the negative side, the index is inadequate. When reading my copy I used lots of colored markers and sticky tabs so I could go back and find important information. The book also has many typographical errors. Clearly, this book went to print in a hurry, though this might be somewhat unavoidable given the subject matter and rate with which technology is progressing. None of the typographical errors cause significant problems with comprehension. Most are like the one on page 12, where the word "enabled" was spelled as "abled." Overall, however, I really enjoyed reading this book. If you are just learning about ADSL technologies, or want to brush up on the subject I highly recommend it.

Duwayne Anderson

The book is well written (by computer book standards :) ), and offers a surprising amount of information about the current US phone system (europeans, africans, etc. are out of luck....). It would have been interesting if there had been information about say Covad, Cisco and others who are actually implementing these technologies.

This book is not good for technical people (they should read Thomas Starr "Understanding Digital Subscriber Line Technology" as the best technical reference book), but this may be a good one for marketing and management people, and for general reading.

As a sales person of department ADSL, I reference new sales people within our company who want to know more on ADSL to read this book first. It starts at the basics, then explains the migration paths, DSL forms, and ends with open issues. It doesn't state, but explains, and gives both the advantages and downsides.

I've read what there was to read on DSL: magazines, whitepapers, books. In the end, I kept coming back to this great book.

This book is exceptionally well-written. xDSL is being touted as 'the next big thing' in telco/internetworking and Mr Goralski does an oustanding job of presenting historical, technical and conceptual information that is complete yet accessible to the non-engineer.

I do technical sales - which is to say being able to translate the telco-arcane to the 'real world' customer and being able to communicate customer needs to central office engineering and product development. Mr Goralski provides a great example of how this can be done well.

This is a very wordy book which dwells more on history than necessary. The technichal information presented is poorly written and lacks depth.
The best part of this book is I bought it used ..., so I didn't loose as much as I could have.

If you read through this book you will get agood understanding of DSL technologies. If youre interested in how it works, then this is the book for you. Well written and easy to read. I would recommend this title.

This book takes you from ground zero to explain how the many protocols and technologies work. There are plenty of diagrams with extensive explanations on each variant with their advantages and disadvantages.

Much of the information in this book is how the basic telephone system is structures and can apply to many areas besides DSL.

There is way too much detail to scratch the surface with this review so I will just cover some of the highlights.

He covers the emergence of the Internet and web sites with information about ISP's. From there the Public Switched Telephone Network (PSTN) is covered well enough to actually use. Loops and Trunks are covered. This is the mystery boxes in the phone room at work. The differences between analog and digital trunks are described. ISDN and DAML are covered along with the "Law of Large Numbers." Alright now he moves in to the world of Circuit use and Packet Switching. MODEMs yep all kinds 56K, Cable, MMDS, KMDS, and Satellite Systems. DSL's and T1's and so on and so on.

This book is packed with diagrams and statistics. Want to delve deeper then
Appendix A Case studies

Appendix B Sources of Standards and Specification Information
Don't ask me how all this can be packed in one book but it is and I use most of this technologies at work and could not find any slipups.

This book is the most atrociously 'edited' book I've encountered in years. It wouldn't be so bad were it just grammar and punctuation. No, instead, you'll find numerous errors with inconsistent nomenclature, tables, and so on, all of which can't help but confuse one who is encountering the material for the first time.

This book gives a good background on the Remote access market place and how it has evolved. The author includes all the variants of DSL technology and presents the information in a readable style. I would have given it 5 stars but the final editing was poor in that there are many type-setting errors throughout the book.