Data Dissemination on the Web: Speculative and Unobtrusive

The Web rapid growth results in heavier loads on servers/network and in increased latency experienced while retrieving Web documents. Internet traffic is further complicated by its burtiness, which complicates the design and allocation of network components. Bursty traffic alternates peak periods with lulls. The paper presents a framework that exploits idle periods in data traffic to satisfy future HTTP requests speculatively, opportunistically, and unobtrusively. Our proposal differs from previous schemes in that it is server-initiated and it is explicitly aware of current traffic loads (unobtrusive). This paper highlights several design trade-offs and details two issues: (1) server arbitration among several candidate documents, and (2) client/proxy caching. We present a theoretical analysis of arbitration, and we propose an integrated caching strategy for both requested and disseminated documents. Our approach is validated by extensive simulation on server logs, and substantial performance improvements are observed over pure on-demand strategies. (Also cross-referenced as UMIACS-TR-99-23