Experimental Grid Access for Dynamic Discovery and Data Transfer in Distributed Interactive Simulation Systems

Interactive Problem Solving Environments (PSEs) offer an integrated approach for constructing and running complex systems, such as distributed simulation systems. New distributed infrastructures, like the Grid, support the access to a large variety of core services and resources that can be used by interactive PSEs in a secure environment. We are experimenting with Grid access for interactive PSEs built on top of the High Level Architecture (HLA), a middleware for interactive simulations. Our current approach is such that once a PSE simulation has been executed in the framework, mechanisms from both HLA and Grid middleware are used to broker resources, for job submission services, performance monitoring services, and security services for efficient and transparent execution. We are experimenting with the Web-based Open Grid Services Architecture (OGSA) for HLA RTI Federate registration and discovery, as well as for data transmission. We have found that Grid Services give the possibility to allow for dynamic modification capabilities of HLA Federates, though the dynamic discovery of Federates and the use of Service Data (metadata) for service introspection is not trivial. Also, we have found that opening many data transmission channels between HLA Federates to one destination affects the number of connections you can make with other destinations.