Publishing and finding web service descriptions Appendix 1: Web Services and a Service-Oriented Architecture Application End user Applications service layer Service provider Service: Service: Service: services authentication billing services Other Services Database services bank account Credit card services Credit card Credit card service other services Figure A1.2 An application that is composed from different sources Most web service applications will, most likely, be built on new or existing web tech- nologies, including HTTP, XML, SOAP, SSL, WSDL, and UDDI. (See glossary). SOAP (Simple object access protocol) allows a program running in one kind of operating system to communicate with a program in the same or another kind of an operating system (e.g. Linux Vs Windows) by using HTTP and XML as the mechanisms for information exchange. In effect SOAP is a platform-independent access protocol. The request for a web service is sent to an HTTP server. There are different methods to translate the information carried by HTTP (over TCP/IP) to XML protocol. A service-oriented architecture may have impact on network design and QoS. When the end user requests a service the main issue is to analyse the required capabilities and choose proper process handling based on a viable architecture. Choice of appropriate service enablers is part of such process handling. The 'software as a service' concept offers advantages and disadvantages. Sharing resources would normally imply cost benefits. Regarding QoS the remote access is a drawback, also for the security, but the possibility to provide alternative remote accesses as back-up will instead have a positive impact. Obviously the service-oriented architecture can solve many network architecture problems, when using service resources on demand across the network. This is an interesting area for network architects and designers. Among the main challenges are no doubt the QoS and security issues. Appendix 2 Financial Calculations FINANCIAL CALCULATIONS AND INVESTMENT ANALYSIS Impor