PPSP

This document specifies the base Peer-to-Peer Streaming Tracker Protocol (PPSTP) version 1, an application-layer control (signaling) protocol for the exchange of meta information between trackers and peers. The specification outlines the architecture of the protocol and its functionality; it also describes message flows, message processing instructions, message formats, formal syntax, and semantics. The PPSTP enables cooperating peers to form content-streaming overlay networks to support near real-time delivery of structured media content (audio, video, and associated timed text and metadata), such as adaptive multi-rate, layered (scalable), and multi-view (3D) videos in live, time-shifted, and on-demand modes.

The Peer-to-Peer Streaming Peer Protocol (PPSPP) is a protocol for disseminating the same content to a group of interested parties in a streaming fashion. PPSPP supports streaming of both prerecorded (on- demand) and live audio/video content. It is based on the peer-to- peer paradigm, where clients consuming the content are put on equal footing with the servers initially providing the content, to create a system where everyone can potentially provide upload bandwidth. It has been designed to provide short time-till-playback for the end user and to prevent disruption of the streams by malicious peers. PPSPP has also been designed to be flexible and extensible. It can use different mechanisms to optimize peer uploading, prevent freeriding, and work with different peer discovery schemes (centralized trackers or Distributed Hash Tables). It supports multiple methods for content integrity protection and chunk addressing. Designed as a generic protocol that can run on top of various transport protocols, it currently runs on top of UDP using Low Extra Delay Background Transport (LEDBAT) for congestion control.

Peer-to-Peer (P2P) streaming systems becoming more and more popular on the Internet, and most of them are using proprietary protocols. This document identifies problems associated with proprietary protocols; proposes the development of the Peer-to-Peer Streaming Protocol (PPSP), which includes the tracker and peer protocols; and discusses the scope, requirements, and use cases of PPSP.