RESUMO
Grid application frameworks have increasingly aligned themselves with the developments in Web services. Web services are currently the most popular infrastructure based on service-oriented architecture (SOA) paradigm. There are three core areas within the SOA framework: (i) a set of capabilities that are remotely accessible, (ii) communications using messages and (iii) metadata pertaining to the aforementioned capabilities. In this paper, we focus on issues related to the messaging substrate hosting these services; we base these discussions on the NARADABROKERING system. We outline strategies to leverage capabilities available within the substrate without the need to make any changes to the service implementations themselves. We also identify the set of services needed to build Grids of Grids. Finally, we discuss another technology, HPSEARCH, which facilitates the administration of the substrate and the deployment of applications via a scripting interface. These issues have direct relevance to scientific Grid applications, which need to go beyond remote procedure calls in client-server interactions to support integrated distributed applications that couple databases, high performance computing codes and visualization codes.
