Server-efficient high-definition media dissemination

Abstract

Internet usage has changed dramatically in the past few years. Content is no longer dominated by static websites, but comprises an increasing number of multimedia streams. With the widespread availability of broadband connections, the quality of the media provided by video-on-demand as well as streaming services increases constantly. Even though today most videos are still encoded with a rather low bit rate, large Internet service providers already foresee high-definition media becoming the predominant format in the near future. However, a larger number of clients requesting media at high bit rates poses a challenge for the server infrastructure. Conventional stream dissemination methods, such as RTP over UDP or HTTP over TCP, result in high server loads due to excessive local data copy, context switching, and interrupt processing overhead. In this paper, we illustrate and discuss this problem in detail through extensive experiments with existing solutions. We then present a new approach based on zero-copy protocol stack implementations in software as well as dedicated RDMA hardware. Our performance experiments indicate that these optimizations allow servers to scale better and remove most of the overhead caused by current approaches. Copyright 2009 ACM.