On using BPEL extensibility to implement OGSI and WSRF Grid workflows

Workflow is a critical part of the emerging Grid Computing Environments and captures the linkage of constituent services together in a hierarchical fashion to build larger composite services. As an indispensable element in workflow systems for Grid services, Grid workflow language (and its enactor) serves as the basis for specifying and executing collaborative interactive workflows in Grids. Since Open Grid Services Architecture (OGSA) is built on Web services technology, it is natural to expect that the existing orchestration standards designed for Web services can be leveraged in OGSI based Grids. In this paper we propose a Grid workflow language called Grid Services Workflow Execution Language (GSWEL), which is based on OGSA and provides an extension to Business Process Execution Language for Web Services (BPEL4WS) in order to better support Grid characteristics.