Voice over WLANs, The Complete GuideVoice over WLANs, The Complete Guide
When a new technology or application of a technology surfaces, there are usually many books published about the technology and how it works. Less frequently, there a books that do not tell you how to build the technology, but inform you how to operate and administer the technology. The latter case is Mike Finneran's new book "Voice over WLANs, The Complete Guide", published by Newnes, an imprint of Elsevier (Amazon link here ). This is NOT a book for the hardware/software designer.
May 20, 2008
When a new technology or application of a technology surfaces, there are usually many books published about the technology and how it works. Less frequently, there a books that do not tell you how to build the technology, but inform you how to operate and administer the technology. The latter case is Mike Finneran's new book "Voice over WLANs, The Complete Guide", published by Newnes, an imprint of Elsevier (Amazon link here). This is NOT a book for the hardware/software designer.
When a new technology or application of a technology surfaces, there are usually many books published about the technology and how it works. Less frequently, there a books that do not tell you how to build the technology, but inform you how to operate and administer the technology. The latter case is Mike Finneran's new book "Voice over WLANs, The Complete Guide", published by Newnes, an imprint of Elsevier (Amazon link here). This is NOT a book for the hardware/software designer.You may have met Mike at Voicecon, Interop or one of his seminars or read his BCR columns and nojitter.com postings. He is full of energy and wants to impart as much practical knowledge as possible in the allotted time. He carries this energy over into the WLAN book.
Mike set three goals for himself when writing this book:
Fill in the necessary technical background (VoIP issues, 802.11a/b/g/i/e/etc, fixed mobile convergence)
Provide a practical perspective of how to manage an unmanageable job
Make it readable rather than intimidating
If you collect and read many of the existing VoWLAN books, they are either so "thin" on content that they are "not worth the effort it takes to turn the pages" (Mike's words), or they are so concerned with esoteric technical issues, they avoid the fundamentals. For example, if you're going to be building a network of any significant scale, you should be using a centrally-controlled WLAN switch solution. None of the books Mike read mentions something as basic, obvious and important as that. Mike's book has a chapter on WLAN switches, their common characteristics, and some of the important architectural differences.
Mike commented to me, "VoWLAN is a tough subject because it sits at the convergence of two rapidly evolving disciplines, VoIP and WLANs. On the VoIP front, we have been able to determine what's important in terms of providing acceptable voice quality, and the performance levels we have to reach to meet user expectations. However, achieving that given the inherent vagaries of indoor wireless transmission is a high-order challenge. Add to that the fact that there are very few real high-capacity VoWLAN networks that have been built, so the base of expertise is pretty thin." Mike provides a whole range of practical steps in the book to deal with those real-world challenges.
Mike, who is never shy in making provocative comments, went on to say, "When you look at the level of incompetence that has gone into the initial wave of WLAN deployments, I'm amazed any of these things worked at all! That kind of deployment is not going to support any significant volume of decent-quality voice calling. One of the biggest challenges in VoWLAN is network management. We have no idea where people are going to be when they need to make or receive a phone call. As we will probably 'guess wrong' on the first iteration, we'll need a management system that identifies areas where we are blocking calls or where poor radio coverage is reducing the number of calls we can support (which, of course, results in blocked or dropped calls)." Think of the roaming and signal loss issues when a user changes WLAN access points.
Chapters 1 through 7 of Mike's book cover the wireless technology, access protocols and security. The second half of the book is where the real value lies. This half focuses on the VoWLAN environment. My favorite chapters are:
Chapter 8 - "Quality Issues in IP Telephony" (if you have little or no knowledge or experience with VoIP, then do not skip this chapter)
Chapter 9 - "Voice Network Design and Traffic Engineering" (traffic engineering is something that some voice people know but is absolutely foreign to data network designers)
Chapter 14 - "Network Management in Wireless LANs" (this practical chapter is what is missing in the other VoWLAN books. Do not skip it just because it is at the end of the book.
At the end of the book is an appendix on 802.11 WLAN and related standards. This is followed by a glossary of acronyms and another glossary of terms. Even if you do not read this book to the end, the VoWLAN operator and administrator should have it on the shelf as a continual reference.
If you collect and read many of the existing VoWLAN books, they are either so "thin" on content that they are "not worth the effort it takes to turn the pages" (Mike's words), or they are so concerned with esoteric technical issues, they avoid the fundamentals. For example, if you're going to be building a network of any significant scale, you should be using a centrally-controlled WLAN switch solution. None of the books Mike read mentions something as basic, obvious and important as that. Mike's book has a chapter on WLAN switches, their common characteristics, and some of the important architectural differences.
Mike commented to me, "VoWLAN is a tough subject because it sits at the convergence of two rapidly evolving disciplines, VoIP and WLANs. On the VoIP front, we have been able to determine what's important in terms of providing acceptable voice quality, and the performance levels we have to reach to meet user expectations. However, achieving that given the inherent vagaries of indoor wireless transmission is a high-order challenge. Add to that the fact that there are very few real high-capacity VoWLAN networks that have been built, so the base of expertise is pretty thin." Mike provides a whole range of practical steps in the book to deal with those real-world challenges.
Mike, who is never shy in making provocative comments, went on to say, "When you look at the level of incompetence that has gone into the initial wave of WLAN deployments, I'm amazed any of these things worked at all! That kind of deployment is not going to support any significant volume of decent-quality voice calling. One of the biggest challenges in VoWLAN is network management. We have no idea where people are going to be when they need to make or receive a phone call. As we will probably 'guess wrong' on the first iteration, we'll need a management system that identifies areas where we are blocking calls or where poor radio coverage is reducing the number of calls we can support (which, of course, results in blocked or dropped calls)." Think of the roaming and signal loss issues when a user changes WLAN access points.
Chapters 1 through 7 of Mike's book cover the wireless technology, access protocols and security. The second half of the book is where the real value lies. This half focuses on the VoWLAN environment. My favorite chapters are:
Chapter 8 - "Quality Issues in IP Telephony" (if you have little or no knowledge or experience with VoIP, then do not skip this chapter)
Chapter 9 - "Voice Network Design and Traffic Engineering" (traffic engineering is something that some voice people know but is absolutely foreign to data network designers)
Chapter 14 - "Network Management in Wireless LANs" (this practical chapter is what is missing in the other VoWLAN books. Do not skip it just because it is at the end of the book.
At the end of the book is an appendix on 802.11 WLAN and related standards. This is followed by a glossary of acronyms and another glossary of terms. Even if you do not read this book to the end, the VoWLAN operator and administrator should have it on the shelf as a continual reference.
At the end of the book is an appendix on 802.11 WLAN and related standards. This is followed by a glossary of acronyms and another glossary of terms. Even if you do not read this book to the end, the VoWLAN operator and administrator should have it on the shelf as a continual reference.
