Customer Reviews

SIP Beyond VoIP: The Next Step in the IP Communications Revolution

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

 

 

My first comment is about the title, which promises the book is about SIP beyond VoIP. But the book is virtually all about SIP circa 2003, and almost exclusively about SIP for VoIP transport. Other than a brief excursion into potential uses of SIP in emergency services and mobile communications (still for VoIP, however), the authors never deliver on the promise in the title.

The authors' discussion of SIP is competent, but not remarkable. There are better descriptions available from other authors (e.g. "IP Telephony: Deploying Voice-over-IP Protocols", Hersent et. al, ISBN 0470023597). When the authors talk about current SIP usage, they seem woefully out of touch. For example, they never once mention the open source SIP-based PBX software Asterisk, even though the book has a section on open source software. Asterisk has been a force of nature in the VoIP world since 2004. You'd have to be in a very high ivory tower to miss that.

Much of the book is a rehash of stuff you can read in the SIP RFCs. Sometimes the authors make simple things unclear, as when they say "A SIP transaction consists of a request and a final response." What about the intermediate 1xx responses? Aren't they part of the SIP transaction? The RFC says they are.

Other times the authors express puzzling opinions, such as "[We] believe the IP-PSTN telephony model does not qualify as true VoIP either." What, then, do you call the VoIP services sold by the likes of AT&T, Covad, Sunrocket, and Vonage offering cheap local and long distance phone service to PSTN destinations? I stand perplexed.

When the authors do roll up their sleeves to talk tech, they write a few intriguing paragraphs about a topic and then inexplicably stop, switching gears to the next subject. For example, the discussion on PSTN interactions begins to explain how early media, ringback and other in-band signalling works, then suddenly stops the discussion. Yes, one can scour the Internet for such information, but it would be nice for the authors to simply explain each topic to a consistent level of detail. If they aren't going to talk about things Beyond VoIP, as originally promised, they can at least give readers consistent depth of coverage.

All three authors have impecable credentials, each with a track record in the field and deep involvement in SIP's development. Beyond the misleading title, I expected more quantity and quality from these three experts.

A note on Amazon reviews. Whenever I see a five-star review I always check to see the reviewer's other reviews. It's amazing how often they have none.

The book is a must" for everybody working in the Internet and telecommunication industry and having to do with SIP, from engineers interested in SIP functional, architectural and protocol aspects to product managers looking for new ideas to build innovative communication products.

For SIP engineers, the book is an excellent, very good structured guide through the SIP protocol and its, meanwhile, quite numerous extensions, from basic SIP to SIP-based Presence, Location, Conferencing and Identity services and to the currently emerging peer-to-peer SIP technology. For each topic, the book contains the functional architecture description, the most important protocol aspects and examples. For readers interested to get more technical details, the book also refers, for each topic, to the relevant IETF SIP documents, which are free available at www.ietf.org.

For product managers, the book is a very good overview on the technical possibilities offered by the SIP technology to build new, innovative services, to offer secure VoIP services or to reduce the costs of the SIP infrastructure using an adequate architecture.

This book presents the most complete and up-to-date overview of the SIP technology I am aware of. The SIP technology has become quite complex over the years and the book has shown it is possible to cover the complexity in 300+ pages.

What I particularly credit the book for is it shows the whole SIP roadmap beginning with current status (basics of the sip protocol, sip services, presence, etc.) both deployment-wise and standardization-wise, work-in-progress in the industry (xcon conferencing,xcap provisioning), and ending with 'hot topics' such as peer-2-peer, interconnection of 'sip islands' and multi-network mobility. Even very tricky aspects such as NAT traversal have been addressed in this single book. The presented concepts are well provided with underlying details such as traces of SIP messages, call-flows and snapshots of devices in the market. Despite I consider my own SIP knowledge level over-average, I like to refer to the book for SIP aspects I don't deal with every day. With that, this book is a must-have for bookshelf of anyone who is seriously looking at SIP.

This book provides an excellent knowledge bridge between technicalities of the IETF specifications and the real world experiences. The knowledge shared in 15 chapters is both an excellent introduction for new-comers and a refreshing experience for those who are looking for better understanding what SIP is and how is shaping the communications landscape. I am lucky to have followed the authors at several shows and congresses where their presentations opened the sessions every time with a fresh update from IETF activities and commercial solutions. You can find in this book up to date information, which is seldom found in similar titles. Chapter 5 about Presence, which provides more than a buddy list and offline/online indication, is a good example of explaining something, which everyone heard about, but few understand. The shift from centralized and server based infrastructure to pure Peer-to-Peer systems where intelligence is delegated to the end-point based on the end-to-end principle of the Internet is a view of the future to come, businesses will definitely find the advices exposed in this Chapter 14 as a new niche of developments where competition is still scarce. Chapter 13 about NAT traversal summarizes accurately the problems and the solutions for crossing Network Address Translators. Chapter 10 about how to use SIP by people with disabilities is a proof that SIP can fulfill requirements that PSTN was never able to. Interaction between SIP systems and PSTN is well described and explained Chapter 7 where ENUM is given an accurate X-ray The book balances well excerpts of technical message tracing, configuration samples with clear diagrams, examples of applications and real-life devices.

A must read for software developers, solution implementers as well as business decision makers.

This book is lacking details on everything it tries to cover. If you are looking for SIP protocol level details and understanding as I was, this book is not for you.