This document provides an introduction to web services and how to consume them using PHP. It defines a web service as a distributed unit of business logic that can be accessed over the internet using standard protocols like HTTP and XML. Web services allow businesses to publish, discover and aggregate services over the internet and solve interoperability issues. The document outlines the architecture of web services, including layers like the service listener, interface and implementation. It also describes different ways to consume web services using SOAP, XML-RPC or REST and provides an overview of how to consume a web service using PHP by making SOAP requests via HTTP POST.

1. Introduction to Web Services and HOW-TO in php

5. Web Service VS Web Pages Network Transport Messaging Description Discovery UDDI, WSIL, ebXML WSDL, RDF, ebXML SOAP, XML-RPC(XML)‏ HTTP, SMTP, FTP TCP/IP, UDP LAYERS PROTOCOL/STANDARD

6. Consuming Web Services Service Listener Service Interface Service Implementation Network Calls SOAP Response Execution Return Values/Result Php code SOAP implementation & WSDL Description Apache HTTP server SOAP request via HTTP POST

7. Consuming Web Services Way: SOAP: Simple Object Access Protocol XML-PRC: XML Remote Procedure Call REST : Representational State Transfer