RTP: A transport protocol for real-time applications

July 2003

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Standards

Summary

This memorandum describes the Real-Time Transport Protocol (RTP), designed for end-to-end delivery of real-time data such as interactive audio and video. RTP provides key services including payload type identification, sequence numbering, timestamping, and delivery monitoring. It operates typically over UDP, leveraging its multiplexing and checksum functionalities, but can also work with other underlying transport protocols. RTP does not ensure timely delivery, quality-of-service guarantees, or reliable packet delivery, relying instead on the underlying network for these aspects.

RTP consists of two main components:

  • RTP: Handles the real-time data transfer.
  • RTP Control Protocol (RTCP): Monitors the quality of service and participant information during an ongoing session.

While RTP is primarily used for multimedia conferences, it is also applicable to other continuous data applications. RTP is designed to be adaptable and integrated into application processing, with additional specifications provided through companion documents, including profile and payload format specifications. RTP is intentionally designed as a flexible framework, tailored to specific application needs rather than being a complete, standalone protocol.