Web&: an architecture for non-interactive Web

Abstract

The profile of Web use has changed from information access to e-commerce. The current interactive (synchronous) model is time-consuming. Web browsing can become frustrating if the network or servers incur delays or are not accessible, or if the same interaction must be repeated many times. It is even more painful for clients who are disconnected most of the time or are accessing the Web via low-bandwidth connections and resource-constrained devices. Therefore, there is a need to support non-interactive (asynchronous) transactions between clients and servers on the Web. Such a model is more efficient because: (i) there is reduced sensitivity to network latencies/unavailability, (ii) Web activities can be performed concurrently, and (iii) client mobility can be easily supported. We propose a novel non-interactive service architecture for the Web, called "Web&". The architecture incorporates server and service discovery, support for disconnected and heterogeneous clients, Web transactions via a uniform server interface and a persistent client state. We present a prototype, implemented using Java, XML and JDBC, which consists of client proxies that can store the client state and perform Web queries on a client's behalf, and server proxies that provide a uniform XML-based interface to Web servers. A directory service provides a schema server and service discovery. Even on a single-processor Sun workstation with 512 MB, we can support 25,000 tasks with a peak throughput of 150 tasks/sec. Two applications (IsItLate for flight tracking and IsItThere for package tracking) are currently being run.