Influence of the Document Validation/Replication Methods on Cooperative Web Proxy Caching Architectures

摘要

Nowadays cooperative web caching has shown to improve the performance in Web document access. That is why the interest in works related to web caching architectures designs has been increasing. This paper discusses and compares performances of some cooperative web caching designs (hierarchy, mesh, hybrid) using different document validation/replication methods (TTL, invalidation, pushing, etc). It is shown how the performance in a cooperative web proxy caching architecture is affected by the document validation method that is implemented. Comparing typical caching scenarios we found that speedups for some combinations of distributed caching with validation methods can be between 1.3 and 2.5. If the only criteria of decision to construct a cooperative caching system is response time then it is easily to decide that the combination with a speedup of 2.5 is the best one. However, we found that the bandwidth consumption and the number of stale documents in that combination could be prohibitive. That is why we cannot decide to construct a specific cooperative caching system based on a limited number of decision criterions. This paper shows some trade-off and possible alternatives for constructing a cooperative caching system using different combinations of document validation methods with distributed caching architectures.