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SIGMETRICS 2001 / Performance 2001Characterization of User Access to Streaming Media Files |
| Authors |
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Jussara M. Almeida <jussara@cs.wisc.edu> Jeffrey Krueger <jkrueger@cs.wisc.edu> Mary K. Vernon <vernon@cs.wisc.edu>
Computer Sciences Department, University of Wisconsin-Madison
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| Abstract |
| This paper presents an analysis of server log data for two real-time streaming media servers that deliver education content at two different major U.S. Universities. Our analysis reveals some interesting observations regarding file access characteristics on these servers. For example, during periods of stable request arrival rate, the client session arrival process is approximately Poisson, but the inter-request times for interactive requests are better approximated by a Pareto distribution. The distribution of file popularity are well modeled by the concatenation of two Zipf-like distributions. Furthermore, a significant fraction of the files, or file segments, that are requested in a given hour but not in the previous hour, are not requested again for several hours, which motivates the need to reevaluate the traditional cache-on-first-miss strategy for streaming media files. Finally, high client interactivity in these environments leads to large numbers of partial video file accesses. Nevertheless, the requirements on remote server and network bandwidth can be reduced by 40 to 60% by using multicast delivery. |