sending an XML document in a format called the Simple Object Access Pro- tocol  (SOAP)  over  HTTP.  The  server  has  a  listener  waiting  for  a  SOAP packet. When it receives one, it opens it up, and if everything is in order, it executes the native code. It then takes the results from that code, packages it into another SOAP packet, and returns it to the client. Thats it. So, whats the fuss? Nothing, really; its very simple. What makes it exciting is that this is an industry standard that is being adopted by every major technol- ogy firm. To be concise, Web services are nothing more than code that has been encapsulated by an envelope of reserved words written to a Web Service Definition Language (WSDL) and a Web Service Meta Language (WSML) file. The WSDL and WSML files describe the code, methods, parameters, and data types available for use. This chapter focuses on Web services and SOAP. It discusses the back- ground of Web services, how SOAP fits into the picture, and how distrib- uted programming was accomplished prior to Web services. The chapter discusses the background of Web services and how they are more robust when compared to their RPC predecessors. Furthermore, the chapter dis- cusses  the  pros  and  cons  of  using  SOAP  through  Web  services  and  pro- vides  you  with  information  as  to  what  types  of  businesses  can  benefit using SOAP. Last, the chapter discusses applying security to Web services. This topic is also discussed at length in Chapter 11, Securing the Web Service.” SOAP (The Web Service Protocol) and the General Protocol Pecking Order The Simple Object Access Protocol, better known as SOAP, was introduced to the public in 1998 when Microsoft released its Microsoft SOAP Toolkit 1.0. The objective was to find a simple interoperable technique to receive and transfer a wide range of data across the Internet using well-defined data types. SOAP was created as a collaborative work orchestrated in part by the fol- lowing  companies:  Microsoft,  IBM,  Lotus  Development,  Userland  Soft- ware, and DevelopMentor. Also, a well-known standards body, the W3C (World  Wide  Web  Consortium),  recognizes  and  endorses  the  effort  as  a protocol   that   has   already   received   recommended   status.   Please   read www.w3.og/TR/SOAP/ for more details. Before we delve too far into SOAP, lets discuss the order of nature in the protocol world. Only a fraction of all protocols that exist are listed in the What Are Web Services? 3