The Internet is changing: Static content is giving way to streaming video, text is being replaced by music and the spoken word, and interactive audio and video is becoming commonplace. These changes require new applications, and they pose new and unique challenges for application designers. This book describes how to build these new applications: voice-over-IP, telephony, teleconferencing, streaming video, and webcasting. It looks at the challenges inherent in reliable delivery of audio and video across an IP network, and it explains how to ensure high quality in the face of network problems, as well as how to ensure that the system is secure. The emphasis is on open standards, in particular those devised by the Internet Engineering Task Force (IETF) and the International Telecommunications Union (ITU), rather than on proprietary solutions. This chapter begins our examination of the Real-time Transport Protocol (RTP) with a brief look at the history of audio/video networking and an overview of RTP and its relation to other standards.
|