Performance Enhancements for Distributed Information Systems

This talk will discuss some preliminary results concerning object dissemination in the context of the WWW.

Abstract

The interest in distributed information systems seems to be irreversible. The World-Wide Web (WWW) is a live example of one such system. The WWW component of the Internet traffic profile suggests it will dominate traffic in the near future.

From the client side, one way to help users in terms of system response is to predict what users will want and to prefetch it. We present some insights on how the prediction can be performed. The technique we suggest is sensitive to the user browsing strategy and we will present some examples to illustrate this fact.

Traditionally, caching on the user end has been considered for reducing traffic and latency. This type of caching has been shown to have limitations due to the amount of sharing of WWW objects. Server initiated object dissemination has some benefits over this kind of caching, as the server is able to collect statistics that can be used to decide the worth of caching an object. Questions to be addressed are: "what to replicate," "how much to replicate," "where to replicate," and "how many replicas." The "what to replicate" and "how much to replicate" questions have been previously addressed.

The optimal answer to "where to replicate" and "how many replicas" that minimizes the network load requires full knowledge of the network (topology and functionality), which is intractable with the current network size. In this talk, we present our work on developing a practical approach for object dissemination and present some preliminary results.