Voice over IP fundamentals, 2nd Edition (2007) was authored by Jonathan Davidson with contributions from four other persons and gives detailed information on how voice signals can be transmitted over the internet through IP-based networks. The book details the technology behind the VoIP technology and is relevant to my research question ‘How can voice be transmitted over internet protocol?’
Jonathan Davidson is an employee at Cisco Systems. According to Cisco System’s website, he is the director of product marketing for the Edge Routing Business Unit and has worked at the company for more than 10 years. He has written several books such as Deploying Cisco Voice over IP Solutions and has also written articles on web communication such as VoIP: An in-depth Analysis and Understanding Traffic Analysis.
The four people who contributed to the book are also employees at Cisco systems and hold various positions. James Peters is the director of product marketing and co-authored the first edition of this book, Manoj Bhatia is a technical marketing engineer for the company, Satish Kalidindi is an experienced software engineer with Cisco, and Sudipto Mukherjee is a software development engineer for various telecommunication devices.
Relevance of Book for academic Purposes
Davidson’s contribution to the paper is very important as it comes from someone with more than 10 years experience in the telecommunication industry. When we combine this with the contribution of the other four persons, the book becomes complete and very informative. Each of these five individuals is qualified in a different field of communication technology, but they all come together to combine this knowledge in one book. This makes the book a highly credible source for use as an academic source. Furthermore, the book is published internally by the firm’s own publishing house: Cisco Press, this reduces the errors associated with book publishers. The book was written in 2007and this conforms to the 5-year requirement within which scientific information remains relevant.
Book Summary
Voice over IP fundamentals is divided into 16 chapters that are grouped into 4 parts. The first part covers the first five chapters and centers on Public Switched Telephone Network (PSTN) and its comparison to VoIP. Part 2 covers the next four chapters introduces the audience to the VoIP technology and gives an in-depth analysis of how it works and the role of the different components in a complete VoIP system. Part 3 covers chapters 10, 11, 12 and 13 (Davidson 2007, p. 209). This part covers signaling protocols such as Session Initiation Protocol (SIP), gateway control Protocols and the H.323 protocol. Part 4 is the last part and covers the last two chapters. This section discusses the various applications of the VoIP technology. I will focus on Part 2: Voice over IP Technology as it discusses how the technology works. I will refer to all chapters in my report as they all explain the different components of the VoIP infrastructure. However the report will focus on chapter 7, VoIP: An In-depth Analysis, as it discusses fundamental and complex aspects of the VoIP technology that is useful to both users and developers and is most relevant to my paper (Davidson 2007, p. 370).
How VoIP Works
To make a VoIP call, a person must have a broadband connection, an analogue telephone adaptor (VoIP adaptor) and must be connected to the VoIP provider. The VoIP adaptor is an analog-to digital converter and makes it possible to connect a normal PSTN phone or computer for use with VoIP. It converts analog signals to digital format for transmission (Davidson 2007, p. 213).
The VoIP device, or the VoIP service provider, assigns an IP address to each customer. When a call is made, signals are converted to digital format, then decoded back to analog at the destination by the VoIP provider. The VoIP system assigns an IP address to each phone number so that anytime one makes a call, it is transmitted through an IP address and when it reaches the destination, the provider at the other end directs it to a PSTN (in analogue format).
To enable faster transmission of voice communications, VoIP encodes and compresses the signals in such a way that some components of the voice are lost. However, this process does not affect voice quality, for example, sound signals with frequencies that can not be heard by the human ear are removed. Moments of silence are also removed before the data is sent. If used well, compression of voice calls can elevate VoIP among other forms of voice communication due to its low cost.
Voice over IP fundamentals explains almost every facet of the VoIP technology from the basic operations of PSTN to gate control protocols used to access the VoIP infrastructure. Therefore, it remains the only reference that I’ll use for the paper.
Reference
Davidson, J. (2007). Voice over IP fundamentals, 2nd Edition. Indianapolis, IN: Cisco Press.