Marc Abrams, Stephen Williams, Ghaleb Abdulla, Shashin Patel,
Randy Ribler, Edward A. Fox
Computer Science Department, Virginia Tech, Blacksburg, VA
24061-0106
{abrams,williams,abdulla,spatel,ribler,fox}@cs.vt.edu
Abstract:
We describe how to investigate collections of trace data representing
network delivery of multimedia information with CHITRA95, a tool that
allows a user to visualize, query, statistically analyze and test,
transform, and model collections of trace data. CHITRA95 is applied
to characterize World Wide Web (WWW) traffic from three workloads:
students in a classroom of network-connected workstations, graduate
students browsing the Web, undergraduates browsing educational and
other materials, as well as traffic on a courseware repository server.
We explore the inter-access time of files on a server (i.e., recency),
the hit rate from a proxy server cache, and the distributions of file
sizes and media types requested. The traffic study also yields
statistics on the effectiveness of caching to improve transfer rates.
In contrast to past WWW traffic studies, we analyze client as well as
server traffic; we compare three workloads rather than drawing
conclusions from one workload; and we analyze tcpdump logs to
calculate the performance improvement in throughput that an end user
sees due to caching.