.Net WCF     ASP.NET gives .NET Framework class libraries and tools for building Web services, as well as services for hosting services within Internet Information Services (IIS). Dot Net Windows Communication Foundation (WCF) provides .NET Framework class libraries, tools and hosting services for enabling software entities to converse using any protocols, including those used by Web services. Migrating ASP.NET Web Services to WCF allows your applications to take benefit of new features and improvements that are exclusive to WCF. Dotnet WCF has many significant benefits relative to ASP.NET Web services. While ASP.NET Web services tools are only for building Web services, WCF gives tools that can be used when software entities must be made to communicate with one another. This will reduce the number of technologies that developers are required to know in order to accommodate different software communication scenarios, which in turn will decrease the cost of software development resources, as well as the time to complete software development projects. Still for Web service development projects, WCF supports more Web service protocols than ASP.NET Web services support. These extra protocols provide for more complicated solutions involving, between other things, dependable sessions and transactions. Benefits of WCF relative to ASP.NET Web services: Carry on to use ASP.NET Web services, and forego the advantages proffered by WCF. Adopt .Net WCF for new development, while continuing to keep your existing ASP.NET Web service applications. It yields the advantages of WCF, while sparing the price of modifying the existing applications to use it. In this situation, new WCF applications can co-exist with existing ASP.NET applications. New .Net WCF applications will be able to use existing ASP.NET Web services, and WCF can be used to program new operational abilities into existing ASP.NET applications by virtue of WCF ASP.NET compatibility mode. Adopt WCF and migrate existing ASP.NET Web service applications to WCF. You may prefer this choice to improve the existing applications with features provided by WCF, or to reproduce the functionality of existing ASP.NET Web services within new, more powerful WCF applications.