Internet telephony: architecture and protocols - an IETF perspective

Internet telephony offers the opportunity to design a global multimedia com munications system that may eventually replace the existing telephony infra structure. We describe the upper-layer protocol components that are specifi c to Internet telephony services: the Real-Time Transport Protocol (RTP) to carry voice and video data, and the Session Initiation Protocol (SIP) for signaling. We also mention some complementary protocols, including the Real Time Streaming Protocol (RTSP) for control of streaming media, and the Wid e Area Service Discovery Protocol (WASRV) for location of telephony gateway s. (C) 1999 Published by Elsevier Science B.V. All rights reserved.