Infrastructure-independent applications using haggle

Haggle is a software architecture for mobile devices, such as smart phones, PDAs and laptops, allowing ap-plications to use peer-to-peer and mobility-based con-nectivity as easily as they currently use infrastructure. This is an important capability for many UbiComp ap-plications due to the dynamic connectivity environment faced by the mobile devices employed. We illustrate Haggle’s benefits using the examples of email and web browsing. BACKGROUND Ubiquitous computing applications are often set against a backdrop of highly mobile people and devices, where the network connectivity varies greatly over time. How-ever, existing network architectures for these devices are unable to make full use of the connectivity available. Even current-day applications are hobbled by this — one ubiquitous example is that of two people with lap-tops sitting next to each other, who cannot email a file they wish to share because infrastructure is either un-available, not working properly, or too costly. Recent efforts have started to alleviate such problems. The Delay Tolerant Networking (DTN) [2] research group is creating protocols for scenarios where TCP/IP net-working is not feasible, such as when there is no con-temporaneous end-to-end link or the delays are very long. Networking methods making use of planned or opportunistic node mobility have been discussed, e.g. “message ferries ” [6]. Also, recent sensor network de-ployments on mobile animals have made use of animal mobility in this way [4]. Our focus is on the scenario of Pocket Switched Net-working [3], which describes the networking environ-ment experienced by the devices carried by mobile users. These devices typically have one or more local network-ing interfaces (e.g. 802.11, Bluetooth), with which they can exchange data with neighbours. Devices may also have access to the Internet through one or more global connectivities, e.g. through 802.11 or GPRS; these dif-fer in price, bandwidth, and availability. User mobil-ity [1] means that the set of neighbouring devices and the availability of Internet connectivity is dynamic