Markdown

RTP

RTP is the Acronym for Real-time Transport Protocol

A network protocol designed for delivering audio, video, and other real-time data over IP networks. Standardized by the IETF, it forms the backbone of many streaming, telephony, and video conferencing systems. RTP itself handles the end-to-end delivery of media streams, ensuring that packets carry timestamps, sequence numbers, and payload type identifiers so that receivers can reconstruct the timing and order of the media. Because RTP is focused on transport rather than security or session control, it is often paired with complementary protocols. For example, RTCP (RTP Control Protocol) provides monitoring, quality-of-service feedback, and synchronization between multiple streams. For secure communications, RTP can be extended with encryption and authentication layers, most notably Secure RTP (SRTP) for confidentiality and integrity and ZRTP, a key agreement protocol for establishing encryption keys directly between endpoints. RTP underpins many modern communication technologies, including VoIP, WebRTC, and video conferencing platforms, making it one of the most widely used standards in real-time communications.

Core Functionality

RTP is used in communication and entertainment systems that involve streaming media, such as telephony, video teleconference applications including WebRTC, television services and web-based push-to-talk features. RTP typically runs over User Datagram Protocol (UDP). RTP is used in conjunction with the RTP Control Protocol (RTCP). While RTP carries the media streams (e.g., audio and video), RTCP is used to monitor transmission statistics and quality of service (QoS) and aids synchronization of multiple streams. RTP is one of the technical foundations of voice over IP and in this context is often used in conjunction with a signaling protocol such as the Session Initiation Protocol (SIP), which establishes connections across the network.

Complementary Protocols

  • RTCP (RTP Control Protocol): Provides monitoring, quality-of-service feedback, and synchronization between multiple streams.
  • SRTP (Secure RTP): Extends RTP with encryption and authentication layers for confidentiality and integrity.
  • ZRTP: A key agreement protocol for establishing encryption keys directly between endpoints.

Applications

  • VoIP (Voice over IP): RTP is a foundational protocol for VoIP systems.
  • WebRTC (Web Real-Time Communication): Enables real-time communication in web browsers.
  • Video Conferencing Platforms: Used extensively in video conferencing applications.