SIP Trunking – Review

When I first got started working with Voice-over-IP (VoIP), I was excited about all the possibilities of making calls over the Internet and moving away from my old reliance on Ma Bell.  However, the reality of my continued dependence on the good old phone company is an ever-present reminder that sometimes technology needs to mature a little before I can make bigger leaps.  That’s why the idea behind SIP trunking has me excited.  It brings back a little bit of that hopeful magic from my early days of VoIP possibilities.  Thanks to Christina Hattingh, Darryl Sladden, and ATM Zakaria Swapan and the good folks over at Cisco Press, I got my feet wet with SIP Trunking:

This is the “pound cake” of Cisco Press books.  It’s only about 300 pages and a bit on the thin size, but it’s a very dense read.  Part 1 covers the differences between traditional Time-Division Multiplexing (TDM) trunking and SIP trunking.  There is discussion of the cost and benefit of moving to a hybrid model or even to a pure SIP environment.  This is a good part to focus on if you aren’t familiar with SIP trunking in general or you are trying to convince your decision makers to give it a try.

Part 2 is all about planning.  One hundred plus pages of modeling and design and checklists.  An engineer’s dream.  You are going to spend a lot of time in here dissecting the cutover strategies and the list of questions that you need to ask your provider before delving into the SIP-infested waters.  In fact, I would recommend this book for Chapter 9 alone, the checklist chapter.  It goes into great detail about all the questions you need to ask your provider, along with a description of each question and why the answer would be so important to you.

Part 3 is the deployment guide.  No Cisco Press book is complete without some code examples, and Chapter 10 has them in spades.  One thing I did like about their examples of AT&T and Verizon configuration is that they are appropriately annotated with notes to be sure you understand why a particular setting was configured.  I want to see more of this in the networking-focused Cisco Press books, not just the planning ones.  There are also case studies to help you make decisions and a chapter on the future of Unified Communications.  This one’s kind of dubious, though, as most of the time the predictions either end up looking hilariously obvious in hindsight or wide of the mark.  You can’t fault the authors for wanting to put a little bit of vision in at the end of this read, though.

Tom’s Take

If you want to learn a little more about SIP trunking or you are planning to put one in in the next 6-8 months, grab a copy of this book.  Have a cup of coffee before you jump into it, as the material could be a little dry if you aren’t focused on the task at hand.  Make sure to dog-ear the first page of Chapter 9, as you’ll find yourself coming back here more and more as you start implementing your SIP trunk.


This book was provided to me as a perk at Cisco Live for being a NetVet.  I chose this book from a list of the available titles and it was provided to me at no charge above the cost of the conference.  Cisco Press did not ask for nor did I promise any kind of consideration in the above review.  The thoughts and opinions expressed above represent my true and honest opinion of the material.

2 thoughts on “SIP Trunking – Review

  1. Pingback: Show 87 – A SIP of Voice

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