Delfos: the Oracle to Predict NextWeb User's Accesses

Abstract

Despite the wide and intensive research efforts focused on web prediction and prefetching techniques aimed to reduce user's perceived latency, few attempts to implement and use them in real environments have been done, mainly due to their complexity and supposed limitations that low user available bandwidths imposed few years ago. Nevertheless, current user bandwidths open a new scenario for prefetching that becomes again an interesting option to improve web performance. This paper presents Delfos, a framework to perform web predictions and prefetching on a real environment that tries to cover the existing gap between research and praxis. Delfos is integrated in the web architecture without modifying the standard HTTP 1.1 protocol, and acts inserting predictions in the web server side, while prefetchs are carried out by the client. In addition, it can be also used as a flexible framework to evaluate and compare existing prefetching techniques and algorithms and to assist in the design of new ones because it provides detailed statistics reports.

Referrer Graph: A cost-effective algorithm and pruning method for predicting web accesses

“…These clients perform requests to a simulated web server implementing di↵erent prediction algorithms, according to the architecture described and implemented in [19]. The server sends the predictions as hints to the clients for them to prefetch.…”

Improving Web Prefetching by Making Predictions at Prefetch

“…In a previous work [1] we showed how web prediction and prefetching techniques can work efficiently in a real environment without modifying the standard HTTP protocol. To this end, we implemented Delfos, which makes predictions on the server side and the hints are reported to the web browser (also referred to as the web client) included on standard HTTP headers.…”

Key factors in web latency savings in an experimental prefetching system

“…These clients perform requests to a simulated web server with a prediction engine that includes a perfect prediction algorithm according to the Delfos architecture (further details can be found in [14]). This predictor is perfect in the sense that it always provides useful hints, that is, those hints that are associated to objects that will be requested later by the user.…”

“…On the other hand, Ossa et al [14] focused on how to implement web prefetching in real environments making it compatible with commercial products and standard protocols.…”

“…To carry out the experiments we used Delfos [14], a framework developed to study prefetching in a real system. This framework allows developing, testing, and evaluating prefetching techniques.…”