Stream composition for highly adaptive and reconfigurable mobile middleware

Using gateway proxies is one important approach to facilitating adaptation across wireless and mobile environments. Importantly, augmented service entities deployed within the gateway proxy residing on the wired network can be composed and deployed to shield mobile clients from the effects of poor network characteristics. The usual approach to the static composition of service entities on the gateway proxy is to have these service entities interact with each other by explicitly invoking procedures on the named interface. The tight coupling of interfaces inhibits the flexible composition and adaptation of the service entities to the dynamic operating characteristics of wireless networks. We present a Mobile GATEway for the Active deployment of Transport Entities or MobiGATE (pronounced as Mobi-Gate) for short. MobiGATE is a mobile middleware framework that supports the robust and flexible composition of transport entities, known as streamlets. The flow of data traffic is subjected to processing by a chain of streamlets. Each streamlet encapsulates a service entity that serves to adapt the flow of traffic across the wireless network. To facilitate the dynamic reconfiguration of the streamlets, we advocate applying the concept of coordination as the unifying approach to composing these transport service entities. Importantly, MobiGATE delineates a clear separation of interdependency parts from the service-specific computational codes of those service entities by using a separate coordination language to describe the coordination among streamlet service entities. To this end, we have defined a compositional language called MobiGATE Coordination Language (MCL) that provides rich constructs to support the definition of compositions, with constrained type validation and checking.