Customer Reviews

ADSL Standards, Implementation, and Architecture (Advanced & Emerging Communications Technologies)

5 star:		(1)
4 star:		(1)
3 star:		(1)
2 star:		(1)
1 star:		(0)

 

 

There are several "ADSL" titles on the market and most discuss the spectrum of xDSL services, focused on the wire itself. This book is notably different. I have to partially agree with some things that the previous reviewer wrote... this book does not appear to focus on ADSL and the editing is spotty. BUT, like many CRC texts, this book takes a rather technical perspective and focuses more on the protocols *over* ADSL than on the ADSL physical layer itself. This is not an ADSL primer nor is it an xDSL broad survey book, and it is not intended for the neophyte. It does a pretty good job, IMO, of covering the higher layer and implementation aspects for an ADSL product developer. Here's where you'll learn about ADSL frame formats, ATM over ADSL, and signaling protocols, but you won't see ADSL business applications, sample products, nor a debate about CAP vs. DMT.

This book provides a concise, readable treatment of ADSL, and is useful in placing ADSL within the context of a total implementation. The book begins with a short, intuitive treatment of analog and digital communications that highlight some of the key design issues. Then there is a good survey of alternative DSL techniques. Chapter 3 covers the ADSL transmission technology. At only 20 pages, the chapter necessarily sticks to a concise overview. The reader looking for a detailed examination of ADSL will not find it here. However, the remainder of the book looks at other communications design issues that must be addressed in implementing ADSL. This include the communications software that rides on top of the ADSL physical layer, the buffering required at each end of the line, signaling protocols, and interface chipset design. The book also introduces the topic of ATM over ADSL and looks at the issues involved there. For the reader looking for this type of broad treatment, covering related issues as well as ADSL design, this book is a good choice.

I have no idea just what the one reviewer thought that he "knew to be the truth" about ADSL, or where he learned it -- but the technical information in the book seemed to be both accurate and relevant -- from the context of comparison with other ADSL technical references -- Chen, Rauschmayer, ADSL Forum, and ANSI and ITU-T specifications. It contains less information about the ADSL trasmission protocol than Chen or Rauschmayer but much more than Goralski and presents a greater breadth than Rauschmayer. It IS, however, a technical book rather than a marketing book and, therefore, does not cover the political aspects or business applications in great depth.

The book does have a problem, however, in that the chapters dealing with the physical layer make assumptions about the readers background. If the reader is familiar with digital transmission framing architectures, the chapter on ADSL presents a well-written and organized summary of ADSL-specific physical layer attributes. Without this background, the material can become very confusing. For example, he talks about the ADSL control channel commands without really explaining what a control channel is. In an apparent attempt to avoid the mathematical formulas needed, the distinction between QAM and CAP is blurred somewhat. If this ranking system had 1/2 stars, I would deduct a half star for this.

It is too bad that the one reviewer did not bother to read the rest of the book -- ADSL is of very little practical use without the surrounding protocols and applications -- and the physical layer will normally be handled transparently by the hardware anyway. I haven't read "Implementing ADSL" yet but,from the description, it also looks like a book that takes a system point of view of ADSL.

If this book ever does go to a second edition, I hope the assumptions are better eliminated and specific products are added as examples.

I found that this book did not contain very much information about ADSL. What was covered was unclear, poorly written and poorly edited, if edited at all. The book contains 10 chapters, only two of which were geared towards ADSL. Other chapters contained lots of general information about communications, such as: basics of analog & digital comm, various flavors of xDSL, OSI model, physical layer semiconductors, memory maps, state machines, routers, IP, and networking. I often found statements that the author put on paper about the ADSL physical layer which seemed to be contrary to what I know to be the truth, or at least worded poorly enough that they seemed to be so. Complex diagrams were copied from the ADSL standards with little explanation of what they meant. My general impression was that the author attempted to write a book containing material that was more technical than his background could support. After reading the small amount of material in it that had very much to do with ADSL, I put the book down and did not finish it.