Walkabout: Asynchronous Messaging Support for Mobile Devices

We propose Walkabout, an asynchronous Internet messag-ing architecture designed to support data transmission between mobile devices with intermittent connections. A Walkabout-enabled device sends data messages via a proxy within its lo-cal network. The proxy creates a peer-to-peer overlay with other proxies in remote networks to deliver each message to the destination device(s). The overlay caches the message if a destination device is unavailable, migrates the message to follow devices as they move, and allows devices to resume uploads or downloads from different locations if interrupted. In this paper, we present the design of the architecture and its associated protocols. We present some potential applications, and show through simulation that Walkabout maximises local network use and provides significantly faster delivery times than the existing alternative methods under a range of device mobility patterns