DocumentCode :
813859
Title :
Limitations and benefits of cooperative proxy caching
Author :
Dykes, Sandra G. ; Robbins, Kay A.
Author_Institution :
Dept. of Comput. Sci., Texas Univ., San Antonio, TX, USA
Volume :
20
Issue :
7
fYear :
2002
fDate :
9/1/2002 12:00:00 AM
Firstpage :
1290
Lastpage :
1304
Abstract :
Cooperating proxy caches are groups of HTTP proxy servers that organize to share cached objects. This paper develops analytical models for proxy cooperation which use speedup in user response time as the performance metric. Speedup expressions are derived for the cooperation upper bound, a proxy mesh, and a three-level proxy hierarchy. The equations compare fundamental design approaches by separating the proxy organization for object delivery from the mechanism for object discovery. Discovery mechanisms analyzed for the mesh and hierarchy models include ideal discovery, Internet cache protocol (ICP) query, and distributed metadata directories. Equations are evaluated using parameter estimates from experiments and from analysis of cache trace logs. Results indicate that proxy cooperation is marginally viable from the standpoint of average user response time, and that the miss penalty for the hierarchy renders it less viable than the mesh. Proxy cooperation can, however, reduce the variability in user response time and the number of long delays. A trace-driven simulation shows that caching constraints have little effect on cooperation performance due to request filtering by lower level caches.
Keywords :
Internet; cache storage; distributed databases; meta data; parameter estimation; protocols; HTTP proxy servers; ICP query; Internet cache protocol query; cache trace logs; caching constraints; cooperation upper bound; cooperative proxy caching; discovery mechanisms; distributed metadata directories; ideal discovery; miss penalty; object delivery; object discovery; parameter estimates; performance metric; proxy cooperation; proxy mesh; proxy organization; request filtering; share cached objects; speedup expressions; three-level proxy hierarchy; trace-driven simulation; user response time; Analytical models; Cache memory; Delay; Equations; Internet; Measurement; Parameter estimation; Protocols; Upper bound; Web server;
fLanguage :
English
Journal_Title :
Selected Areas in Communications, IEEE Journal on
Publisher :
ieee
ISSN :
0733-8716
Type :
jour
DOI :
10.1109/JSAC.2002.801750
Filename :
1031902
Link To Document :
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