Extending the MIAS-Equator Toolkit to Intermittently Available Network Environments

The present service oriented approach to grid compu ting is designed to support synchronous operations on always connected services and cannot easily be used to support asynchronous, intermit- tently connected services on the grid. Middleware, such as the globus toolkit assume the availability of a permanent connection to a grid service. However, many applications require the integration of services and clients which are mobile, and consequently only intermittently connected to the fixed Grid infrast ruc- ture. The Grid Based Medical Devices for Everyday Health project has produced a toolkit designed to expose a wearable medical sensing devices as OGSI grid services, to explore the extent to which the gr id can support remote patient monitoring; intermittent network availability was found to be a critical pr ob- lem for grid based mobile sensing applications. This paper describes a framework for supporting both mobile grid clients and services in an intermit- tently connected network environment. A prototype implementation has been developed and used to support the operation of the wearable medical devic e described above. Initial tests show the framework successfully supporting invocations in the face of intermittent network non-availability. Grid Computing symbolises a vision in which users share and access compute and storage resources, such as databases, processor servers and mobile dev ices, which are distributed across large geographic al areas and multiple organisational boundaries. One a pproach to grid computing utilises a service-oriented architecture in which clients interact with resources through e ntities known as grid services. The Open Grid Services Infrastructure (OGSI) (OGSI) defines a standard set of facilities for interacting with t hese grid services. There are many applications which would benefit from using service-oriented grid techniques to sup- port mobile/remote devices. The Eqautor eScience program has used grid services to facilitate the inter ac- tion with a remote environmental monitoring device deployed in the Antarctic (Antarctic). The Grid Based Medical Devices for Everyday Health project has produced a toolkit designed to expose sensing devices as grid services; this toolkit has been use d to explore the extent to which the grid can be us ed to support wearable mobile sensing devices for health monitoring purposes (Medical). These projects have: demonstrated a clear need for OGSI to support mobile applications; identified that OGSI is designed to support synchronous, always connected services and cannot easily be used to facilitate the interaction with asynchronous, intermittently connected grid se rvices and resources. This workshop paper describes a framework which can be used to support interaction with OGSI grid clients and services on intermittently available de vices. The paper also describes a test scenario in w hich the framework has been used to extend the toolkit d escribed above to support the interactions with a wearable medical sensing device. The work combines techniques from mobile aware protocols and mid- dleware to specifically address Grid requirements a nd idioms.