Open Grid Services Architecture (OGSA) is a set of standards defining the way in which information is shared among diverse components of large, heterogeneous grid systems. In this context, a grid system is a scalable wide area network (WAN) that supports resource sharing and distribution. OGSA is a trademark of the Open Grid Forum.
OGSA definitions and criteria apply to hardware, platforms and software in standards-based grid computing. The OGSA is, in effect, an extension and refinement of the service-oriented architecture (SOA). The OGSA addresses ongoing issues and challenges such as authentication, authorization, policy negotiation and enforcement, administration of service-level agreements, management of virtual organizations and customer data integration.
For a Web service to be considered a grid service, it must allow clients to easily discover, update, modify and delete information about the service's state, define how the service evolves and ensure ongoing compatibility with other services. The goal is to optimize communication and interoperability among resources of all types.