1 An Introduction to the Open Grid Services Architecture (OGSA) and the Open Grid Services Infrastructure (OGSI)

2 Outline Why OGSA? OGSA History OGSI Concepts –Soft State, Discovery, Notification, Naming and Grouping –State Management Debate OGSI Specification –GSH, GSR, Service Data –OGSI interfaces Grid Service, Factory, Notification, HandleResolver, ServiceGroup

3 Why OGSA? Common Architecture for Grid Applications and Middleware Focus on System Integration and Interoperability Best Practises, Defacto standards -> Community Standards Collaboration between Industry and Academia Ubiquituos - Based on Service Oriented Architecture (SOA) and Web Services

4 OGSA History Grid Blueprints (1998) Anatomy of the Grid (2001) Physiology of the Grid New Infrastructure/Protocol Framework for Globus IBM Eliza – Mainframe technology GGF Working Groups split between OGSA and OGSI (proposed recommendation July 2003)

5 OGSI Concepts Utilizes and Extends Web services Soft State, Discovery, Notification, Naming and Grouping State Management Debate –Encapsulation vs Contextualization

6 OGSI Specification: Naming and State Management Primitives Grid Service Handle (GSH) Grid Service Reference (GSR) Service Data Elements (SDE)

7 OGSI Specification: Interfaces Defined Using WSDL –Grid Service, Factory, Notification (Source,Sink,Subscription), HandleResolver, ServiceGroup (Entry, Registration) GridService interface only one mandatory for all Grid services. All other interfaces extends it (exception NotificationSinks)

8 Further Reading