Real Data Transport (RDT) is a proprietary

transport protocol Transport (in British English), or transportation (in American English), is the intentional movement of humans, animals, and goods from one location to another. Modes of transport include air, land ( rail and road), water, cable, pipelin ...

for the actual audio-video data, developed by RealNetworks in the 1990s. It is commonly used in companion with a control protocol for

streaming media Streaming media is multimedia that is delivered and consumed in a continuous manner from a source, with little or no intermediate storage in network elements. ''Streaming'' refers to the delivery method of content, rather than the content i ...

like the

IETF The Internet Engineering Task Force (IETF) is a standards organization for the Internet and is responsible for the technical standards that make up the Internet protocol suite (TCP/IP). It has no formal membership roster or requirements and ...

Real Time Streaming Protocol The Real Time Streaming Protocol (RTSP) is an application-level network protocol designed for multiplexing and packetizing multimedia transport streams (such as interactive media, video and audio) over a suitable transport protocol. RTSP is ...

(RTSP). A non-proprietary alternative for RDT is IETF's

Real-time Transport Protocol The Real-time Transport Protocol (RTP) is a network protocol for delivering audio and video over IP networks. RTP is used in communication and entertainment systems that involve streaming media, such as telephony, video teleconference applicati ...

(RTP), which is also implemented in RealNetworks players. As reported in a 2002 book about firewalls, RDT used two unidirectional UDP connections, one for the data sent from the server to the client and another in the opposite direction for retransmission requests. The same book reported that RealNetworks' G2 server used RDT in this configuration by default. Another 2003 book reported that RDT was also seen carried over

Transmission Control Protocol The Transmission Control Protocol (TCP) is one of the main protocols of the Internet protocol suite. It originated in the initial network implementation in which it complemented the Internet Protocol (IP). Therefore, the entire suite is common ...

(TCP), as a fall-back mechanism. RDT is now included as part of the

Helix Community Helix DNA is a project to produce computer software that can play audio and video media in various formats and aid in producing such media. It is intended as a largely free and open-source digital media framework that runs on numerous operating ...

project.

References

External links

Helix Community RDT implementation
C++ source code repository.
RDT v2
protocol specs from

RDT v3
protocol specs from

{{compu-network-stub Streaming Application layer protocols Data Transport