 Contains services or interfaces that can be accessed over Internet.  Provides certain functionalities and attributes for other applications.  Application requests function from Web service, and it replies back.  Popular in business-to-business interaction.

 Currency conversion application request.  Publisher side- › Create application using common programming language such as Java/J2EE. › Publish interface in WSDL › Publishes WSDL interface in a UDDI registry.  Caller side- › Business requests application by searching UDDI registry. › Obtains URL to access application. › Common Protocol like SOAP would link both sides in a request/response method.

 Stands for Simple Object Access Protocol  Builds further structure on top of XML to make suitable for object access.  Has Envelopes that include Headers and Body.

 Must be encoded using XML.  Must include Envelope and Encoding namespace.  Does not contain DTD references or XML Processing Instructions.  RPC style- › Contains information about the remote method used such as name, type, and value.  Document style- › Only a pure document message is sent. › Example of this would be a purchase order document.  Attachments

 POST /InStock HTTP/1.1 Host: Content-Type: application/soap+xml; charset=utf-8 Content-Length: nnn IBM

 HTTP/ OK Content-Type: application/soap+xml; charset=utf-8 Content-Length: nnn 34.5

 Envelope element tells XML document that it’s a SOAP message.  Header element contains the header information.  Body element contains functions to send and receive information.  Fault element contains information about any errors occurred.

 env:Sender m:MessageTimeout Sender Timeout P5M

 Governed by World Wide Web Consortium.  Sent as an official recommendation in 2003 from version 1.1 to version 1.2.  Became final ‘Recommendation’  Constantly reviewed and has changes made to it.  Version 1.2 is much cleaner, faster, and more versitile.

 Started in very early version. Began with XML version 1.0.  Did not ship right away because of Microsoft politics and other projects.  XML-RPC was later developed, which became SOAP type system.  Today, any changes must be requested to the W3C.

 Addressed around 400 problems.  Clearer processing model – better testing and report generating.  Based on clear XML Information Set - optimization and performance gains.  Works off of existing Web technologies, such as HTTP and HTTP binding.  Much more extensible because of new processing model.  Much more robust in terms of its features.  More flexible – rework features in Envelope or protocol binding.

 Message passes through multiple SOAP nodes – vulnerable to man-in-the-middle attacks.  Vendors need to make sure SOAP node knows what message it is processing.  Malicious code can be placed in XML infoset properties.  HTTP can be a problem with system administrators.

 SOAP is an easy to use standard – use with many different languages.  Easy use with protocols such as HTTP or STMP.  Lightweight – replaces heavy RPC’s such as DCOM and CORBA.  Versatile- works with both versions 1.1 and 1.2.  Multiple operating systems.  Flexibility – opens up different services running on different platforms for third party applications.