Multipath RTP

Multipath TCP enables communicating nodes to use different interfaces and paths to reliably exchange data. In today’s Internet, most applications use TCP and can benefit from Multipath TCP. However, multimedia applications often use the Real Time Transport (RTP) on top of UDP. A few years after the initial work on Multipath TCP, researchers at Aalto university analyzed how RTP to be extended to support multiple path. Thanks to their work, there is now a backward compatible extension of RTP that can be used on multihomed hosts. This extension will be important to access mobile streaming websites that use the Real Time Streaming Protocol (RTSP).

Like Multipath TCP, Multipath RTP allows an RTP flow to be split in several RTP subflows that are exchanged over different paths. Each subflow has its own sequence numbering space to detect transmission error and the RTCP protocol has been adapted to provide feedback about the different subflows.

In a recent paper, Varun Singh and his colleagues describe in more details the algorithms used by Multipath RTP and analyze its performance through measurements with an implementation in the Gstreamer library.


[1] V. Singh, S. Ahsan, J. Ott, MPRTP: Multipath Considerations for Real-time Media, MMSys2013 February 26-March 1, 2013, Oslo, Norway.