Potential and Limits of Web Prefetching Between Low-Bandwidth Clients and Proxies

Department of Electrical and Computer Engineering Department of Computer Science

University of Wisconsin-Madison University of Wisconsin-Madison

qjacobso@ece.wisc.edu cao@cs.wisc.edu

Abstract:

The majority of the Internet population access the World Wide Web via dial-up modem connections. Studies have shown that limited modem bandwidth is the main contributing factor to the Web access latency perceived by the users. In this paper, we investigate one approach to reduce the user-perceived latency: pre-pushing from the proxy to the browsers. The approach takes advantage of the idle time between user Web requests and uses prediction algorithms to predict what document a user might reference next. It then relies on proxies to send (``push'') the documents to the user. Using existing modem Web access traces, we evaluate the potential of the technique at reducing user latency, examine the design of prediction algorithms and measure their accuracy as well as overhead, and evaluate the latency reduction of pre-push schemes using the algorithms.

Our results show that with perfect predictors, proxy-based Web pre-pushing with a 256K-byte pre-push buffer at the browser side can reduce latency by over 20%. Our results also show that prefix-based prediction algorithms works well for predicting user behavior. Proxy-based web pre-pushing driven by real prediction mechanisms can reduce latency by nearly 10%.