rene Shannon, Tom Siracusa, Greg Stiegler, Satyendra Tripathi, and Jennifer Yates. The authors would also like to acknowledge the contributions of Tom Restaino and Gretchen Venditto in the editing of the book. All royalties will be donated to the AT&T Foundation and will be used to support STEM education. Taylor & Francis Taylor & Francis Group http://taylorandfrancis.com Authors John Donovan is chief strategy officer and group president AT&T Technology and Operations (ATO). Donovan was executive vice president of product, sales, marketing, and operations at VeriSign Inc., a technology company that provides Internet infrastructure services. Prior to that, he was chairman and CEO of inCode Telecom Group Inc. Mr. Donovan was also a partner with Deloitte Consulting, where he was the Americas Industry Practice director for telecom. Krish Prabhu retired as president of AT&T Labs and chief technology officer for AT&T, where he was responsible for the company's global technology direction, network architecture and evolution, and service and product design. Krish has an extensive background in technology innovation from his time at AT&T Bell Laboratories, Alcatel, Morgenthaler Ventures, and Tellabs. He also served as COO of Alcatel, and CEO of Tellabs. Taylor & Francis Taylor & Francis Group http://taylorandfrancis.com The Need for Change John Donovan and Krish Prabhu CONTENTS References Although the early history of electrical telecommunication systems dates back to the 1830s, the dawn of modern telecommunications is generally viewed as Alexander Graham Bell's invention of the telephone in 1876. For the first 100 years, the telecom network was primarily "fixed"-the users were restricted to being stationary (other than some limited mobility offered by cordless phones) in locations that were connected to the telecom infrastructure through fixed lines. The advent of mobile telephony in the 1980s, made it possible to move around during a call, eventually ushering in the concept of "personal communication services," allowing