This document discusses the basics of Globus web services and related standards. It describes how Globus team and IBM proposed merging Globus and web services to form OGSA. OGSA led to specifications like OGSI and WSRF. Key web service standards discussed are WSDL for describing services, SOAP for messaging, and UDDI for service discovery. OGSA defines an architecture for building service-oriented grids based on these web service protocols and standards.

1. Some Basics of Globus Web Services Adarsh Patil http://www.adarshpatil.com/

2. GGF-Globus Grid Forum GGF4 was formed on Feb 2002 Globus team and IBM proposed first OGSA specification to merge Globus and Web Services (globus 2.x to globus 3.x) This is a body for designing standards for the Grid.

3. OGSI-Open Grid Service Implementation It is an technical specification for the implementation of Grid Services as described in the OGSA specification Globus Toolkit 3 and 4 are OGSA complaint and are Service Oriented Grid Systems Grid services are transient and stateful. Due to heavy specifications in one and only OGSI (too many specification in OGSI) it does not fit in web services and xml protocols

4. WSRF-Web Service Resource Framework Globus Alliance + IBM + HP --> introduced WSRF to solve this issue ( many implementations in specification of OGSI) WSRF standard promises this effort

5. Web Services Based on Service Oriented Architecture Clients are service Requestors Servers are service Providers XML, http, SOAP, WSDL, UDDI, WS-Inspection language are used Request, Publish, Registry

6. WSDL-Web Service Description Language It’s a XML based specification It is used to describe Web Service It describes What a service can do? Where is its location? How to invoke it ?

7. SOAP-Simple Object Access Protocol It’s a communication protocol for clients and servers to exchange messages in XML format over http It specifies rules, header, body(URI) The message contains SOAP envelope SOAP schema XML schema definition

8. UDDI- Universal Description, Discovery, and Integration Service discovery and registration Used to advertise services Used to find appropriate services Use to publish/obtain services Provider, User, Registry - white pages, yellow pages , green pages

9. OGSA- Open Grid Service Architecture Architecture to build service oriented Grid. It is based on web services It uses protocols such as xml, http Concept of Grid Services was introduced in OGSA It defines various aspect of Grid Service and interfaces that are needed. OGSA-WG is the work group which works on the design of OGSA specification

10. Credits/Acknowledgements http://www.globus.org http://www.globusconsortium.com/ http://www.globusworld.org/ http://www.ggf.org/ Text Books The Grid 2: Blueprint for a New Computing Infrastructure (The Morgan Kaufmann Series in Computer Architecture and Design) The Grid : Core Technologies Grid Computing: Making The Global Infrastructure a Reality