Publish/subscribe delay-tolerant message-oriented middleware for resilient communication

The rapid growth of wireless technologies has resulted in mobile phones and wireless devices becoming essential and ubiquitous elements in everyday domestic and business activity. Wireless devices are also used by emergency and support services. While wireless communication is more flexible than wired communication, it is often not robust, and the coverage is not always complete. In this article, we describe a mobile middleware architecture using delay-tolerant network (DTN) technology, and publish/subscribe concepts. The purpose of the middleware is to add resilience and reach to wireless communications, and reduce battery drainage of the mobile devices and hence extend operational lifetime. The same technology has the potential to provide a fallback communication platform providing greater penetration than that which would otherwise be available in situations where the conventional cellular structure is no longer working or access is limited. It can enable mobile users to connect through the help of multiple radio interface technologies and to exploit physical movement using the inherent relaying capability of DTNs. The approach exploits the synergy between publish/subscribe message-oriented middleware (MOM) and DTN, as neither requires an end-to-end connection at one moment in time. Scenarios based on exploiting any available connection, communication even when there is extreme wireless coverage failure, and a prototype developed on the Android mobile platform are presented. Some relevant issues are also analyzed related to the practical deployment, viz. message routing, energy efficiency, and security.