Adapting the Internet and other IP-based networks to carry voice communications, in addition to traditional data, is an enormous challenge that demands the attention of engineers working on problems ranging from quality of service (QoS) to reservation standards. Taken as a whole, this effort, which encompasses a broad spectrum of high- and low-level technologies, is known as Internet or IP telephony. Volume one of the 'Big Book of IP Telephony' collects the bulk of current IETF documents relating to this critical area of research, providing readers in this rapidly evolving field with the most complete and up-to-date information. Subsequent volumes will be devoted to future IP telephony RFCs, many of which are already under development. This book begins with an incisive introduction to Internet telephony technology, including a look at its likely future directions, as suggested by the most recent efforts of relevant IETF working groups. The RFCs are followed by an extensive index that lets readers pursue specific topics and terms across multiple documents.