Building Telephony Systems with OpenSIPS 1.6 Illustrated Edition

I've been working in the telephony industry for several years now, mainly with Asterisk based systems.My company is currently in need of a SIP proxy to handle load balancing, and least cost routing, so I decided to go with OpenSIPS (which is the most active version of the original OpenSER project today).This book is the best reference on OpenSIPS available (the official documentation on their website is lacking in many regards), and is worth purchasing if you need to learn how to setup and configure OpenSIPS.I'll try to give an honest breakdown of my thoughts on the book.PROS- Contains extremely detailed configuration file directives. This is probably the bulk of the book (snippets of code from the configuration files). This makes the book worth its purchase price.- A great introduction to SIP, which discusses the protocol in an unusually simple manner.- Contains a section on managing OpenSIPS through two different web panels, which is nice for IT people who may need to handle configuration changes from time to time.- Contains a section on LCR, which is obviously extremely important for modern SIP proxies.- Contains a section on billing, which is equally important. Most people setting up SIP proxies are VoIP providers, and need to charge for access.CONS- Lots of typos and grammatical errors. It is obvious that the author is not a native English speaker. While the text was well written, it should have been heavily edited. A lot of the sentences / paragraphs don't make sense, aren't clear, and are confusing.- There is not a good explanation of why configuration directives work the way they do. The author presents valid configuration examples, then just reads off short 1 sentence descriptions of each field. I thought that this could have been written much better, as this is the primary reason most people will purchase the book.Overall, this is a necessary reference for anyone who is using OpenSIPS. It is definitely worth the money, if only for the rather complex configuration samples inside.I hope that the next version of the book has a much more strict review and editing process.

It explains the principles of OpenSIPS pretty well. The thing I wish it would do is give examples of full configurations for a variety of scenarios, but there's always the "osipsconfig" utility that installs with OpenSIPS, so maybe we don't need the book to go through it.I guess it's kind of the norm with software books that they don't quite tell you the thing you want to know, or show you the example you want to see. Maybe the authors know something I don't, and there's no such thing as one-size-fits-all examples.

Easy to read. The author begins by explaining in detail the SIP protocol, abstracting the reader of the always painful RFCs. Then he takes us into the world of OpenSIPS together with a number of practical examples.The book also covers some aspects of the integration of OpenSIPS with Asterisk, which was precisely what I was looking for.I highly recommend this book. Worth the money.

Its a great read, but more importantly, when your stuck trying to figure something out with the config, you can go back to this and find what you need .

Being the only book on opensips and fairly well written, I had to give this 5 stars. But it does have a couple of flaws. It refers to other sections occasionally which if it included the page or section number, it would help considerably. On one occasion, the section does not exist.If I remember right (I've had it 10 months) at least one of the code samples was not modified correctly when he converted his openser version of the book, but generally he brings together lots of information available on the internet into one readable book and his code examples are pretty good.I nearly gave it 4 stars, because I feel he could have so easily added an advanced section. How about developing your own modules, integrating perl, NOTIFY and SUBSCRIBES, load balancing, connecting to other VOIP services etc.Still, the section on NAT is very good (and essential reading for anybody intending to use Opensips across the Internet). The integration with Asterisk is also pretty good.I used this book time and time again but only recently have moved onto reading RFCs for the in depth information I need.If Flavio wrote an advanced opensips (or even a real life SIPS implementation book) I would buy that also.

Libro imprescindible para aquellos que se dediquen al opensource con VoIP. Muy bueno. Lo recomiendo, de verdad. Para mi coleccion tecnica y como consulta lo he utilizado muy a menudo.