1. SOAP TECHNOLOGY What is SOAP ? SOAP is a simple, lightweight XML protocol for exchanging exchanging structured and typed information on the Web Extensible No application semantics and no transport semantics

2. Who is drafting SOAP ? u UserLand, Ariba, CommerceOne, Compaq, Developmentor, HP, IBM, IONA, Lotus, Microsoft, SUN and SAP. u SOAP specification v1.1 already a W3C standard. v1.2 has recently been submitted.

3. Why SOAP? u Important need in Internet application development to allow communication between apps. u The politics of serialization : Several large factions each loyal to its own particular RPC ( remote procedure call ) protocol - DCOM, CORBA, Java RMI u SOAP addresses the interoperability issue at the data serialization level

4. Bringing down the walls u These systems could interact using bridges but they add costs and hurt performance. u Made decisions to standardize on one or the other ; then used message-oriented middleware for integration. u If Web browsers can, why not remote services? u SOAP - simplicity, flexibility, platform- neutrality and text-based.

5. RPC revisited u SOAP - a standard way of serializing the info. needed to invoke remote services into a format and transported across the wire, then recreated at destination. u To understand SOAP better : a look at DCOM’s RPC architecture. u Primary design goal of DCOM was “location transparency”.

6. DCOM Architecture u Location transparency in DCOM using the proxy/stub architecture. DCOM uses the NDR serialization scheme. u SOAP uses XML to structure the data serialization.

7. SOAP and...HTTP ?! u More than a data serialization format to do real RPC….transfer messages to the server and return the response. u DCOM and CORBA are incompatible when addressing endpoints, activating remote objects... u HTTP most conducive Internet Protocol for RPC via SOAP msgs : -URLs,Synch. Blocking, Scalable,Secure

8. The Firewall blues u DCOM and CORBA IIOP not firewall friendly, use oddly-numbered ports etc. u HTTP traffic over port 80 usually can talk through firewalls. u SOAP messages treated as a new MIME type to be carried in a HTTP payload : so HTTP headers indicate packet has SOAP request, better firewall control.

9. SOAP building block

10. SOAP Building block ( cont’d ) u A SOAP message is an ordinary XML document. u The XML document contains the following XML elements: u - A SOAP envelope, defines message content u - A SOAP header(optional), contains header information u - A SOAP body, that contains call and response information

11. A SOAP Example u A SOAP request embedded in an HTTP Request: u u IBM u 

12. A SOAP Example (Cont’d ) u A SOAP response embedded in an HTTP Response u u 113.81 u 

13. SOAP Summary u SOAP is u - a lightweight comm. protocol u - is based on XML u - designed to communicate via HTTP u - not tied to any component technology or programming language. u - simple and extensible u - a W3C standard

14. Thankyou!