Web Services is fundamentally an application development framework, which includes a holistic set of guidelines and specifications that provide The Ultimate Guide to Building and Delivering OSS/BSS platforms, tools and programming environments for addressing the design, integration, performance, security and reliability of distributed and multi- tiered applications. An application framework includes the presentation services, server-side processing, session management, business logic framework, application data caching, application logic, persistence, transactions, security and logging services for applications. There are multiple providers of application framework, such as IBM, BEA and Microsoft. Application frameworks for client-server and Web-based applications can broadly be classified into two distinct fundamental physical architectures and technologies - Microsoft .NET and Java 2 Platform, Enterprise Edition (J2EE). The war between .NET and J2EE is well under way and expect the Web Services technology to be the winner. What Are the ISVs Doing? In the midst of all these next-generation network advancements and a revolution towards component-based architectures, what are the OSS Independent Software Vendors (ISVs) doing? ISVs have been a little slow in providing software that can effectively manage next-generation networks. However, there is a definite trend towards ISVs "componentizing" their software, separating order management from inventory from activation for example. They are also providing open APIs, though hardly any of them support the Web services standards XML and SOAP. There are three distinct categories of ISVs: First category being the ISVs that have application built on old technology (C and C++) and still continue to provide mainly CORBA-based interfaces with a well-defined fielded structure format. These are usually some of the ISVs that have been in the market for a while are basically morphing their voice-OSS into next- generation systems. The second category of ISVs have traditional back-