• Summary
• Related Documents
  • Active Bibliography
  • Co-citation
• Version History

Abstract:

This paper investigates an architecture and implementation for the use of a TCP-friendly protocol in a scalable video distribution system for hierarchically encoded layered video. The design supports a variety of heterogeneous clients, because recent developments have shown that access network and client capabilities differ widely in today’s Internet. The distribution system presented here consists of videos servers, proxy caches and clients that make use of a TCP-friendly rate control (TFRC) to perform congestion controlled streaming of layer encoded video. The data transfer protocol of the system is RTP compliant, yet it integrates protocol elements for congestion control with protocols elements for retransmission that is necessary for lossless transfer of contents into proxy caches. The control protocol RTSP is used to negotiate capabilities, such as support for congestion control or retransmission. By tests performed with our experimental platform in a lab test and over the Internet, we show that congestion controlled streaming of layer encoded video through proxy caches is a valid means of supporting heterogeneous clients. We show that filtering of layers depending on a TFRC-controlled permissible bandwidth allows the preferred delivery of the most relevant layers to end-systems while additional layers can be delivered to the cache server. We experiment with uncontrolled delivery from the proxy cache to the client as well, which may result in random loss and bandwidth waste but also a higher goodput, and compare these two approaches.

Citations