Syxaw: Data Synchronization Middleware for the Mobile Web

In this paper, we present a middleware for synchronization of opaque and structured data in a mobile and resource-constrained environment. The presented Syxaw (Synchronizer with XML-awareness) system distinguishes itself from related proposals in that it interoperates transparently with resources on the World Wide Web, and by exhibiting a model of synchronization that is both easy to understand and well suited for weak devices in a mobile and ubiquitous environment. We demonstrate the feasibility of the proposed system by considering several usage scenarios, including working on the Web and collaborative XML editing. We consider system performance on a mobile wireless device, and examine the impact of different optimization techniques to the performance. According to our analysis, Web interoperability suggests that the data share model be kept simple and conservative, and that moving functionality onto the client is advantageous. We find that the techniques of operation bundling and concurrent use of network downlink and uplink improve network utilization, but that achieving full bandwidth usage with a weak client is challenging in practice.