Voice over IP Fundamentals

Rating:
Summary: Basic, but maybe useful if you are new to the subject
Review: This book is properly titled: It only covers Fundamentals. It is obviously not written by polished writers, and I cringed when the word "it's" was misused in the first paragraph. But, unless you want detailed, well-written technical documentation, the book might be OK for you.

Rating:
Summary: Very good book on VoIP fundamentals
Review: This book is the one to read if you want to know something about the basics of Voice Over IP and the protocols which are involved like H.323. It also gives you an introduction to the POTS ( plain old telephony service ) standards. So, if you are new to VoIP and want to read about it from the ground, buy this.

But it is not the right choice if you are searching for preparation material for the cisco #640-647 cvoice exam. For that exam you also have to know something about VoFR and VoATM, which is not covered deeply enough here.