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ASP.NET is the next generation of Active Server Pages (ASP) technology. While ASP.NET is largely syntax compatible with ASP, it also provides a new programming model and infrastructure that allows you to create a powerful new class of applications, and it provides robust XML support.

In ASP.NET, code is compiled. When a user requests a page the first time, the runtime compiles the code and the page itself, and keeps a cached copy of the compiled result. When a user requests the page a second time, the cached copy is used. This results in greatly increased performance because, after this first request, the code can run from the much faster compiled version and the content on the page does not need to be parsed again.

ASP.NET allows you to use and create XML Web services. XML Web services provide the building blocks for constructing distributed Web-based applications. An XML Web service is an application delivered as a service that can be integrated with other XML Web services using Internet standards. For example, a company can assemble an online store by using the Microsoft Passport service to authenticate users, a third-party personalization service to adapt Web pages to each user's preferences, a credit-card processing service, a sales tax service, package-tracking services from each shipping company, and an in-house catalog service that connects to the company's internal inventory management applications.

ASP.NET files have an .aspx file extension, while XML Web services have an .asmx extension. The technologies are similar; however, instead of outputting HTML, an XML Web service outputs a computer-readable answer to the input it receives.

ASP.NET has many benefits over ASP for the system administrator:

• Configuration and deployment are now easier with the use of human-readable configuration files and DLLs that do not need to be registered.
• All the configuration details for all Web applications are kept in human-readable files named Web.config. The standard format for the configuration files is XML, and each application inherits the settings in the default Web.config file.
• All files that a Web site needs are located under the site's root folder. DLLs are in the /bin folder, and the Web.config file is in the root folder. To deploy a Web application, all you need to do is copy the site's root folder by using file copy commands, the Microsoft FrontPage® server extensions, or FTP.
• Files that run from the /bin directory are actually run from copies of the files. If you need to update the ASP.NET application, all you have to do is copy over the old files with the new ones. The DLLs are not locked when in use, and ASP.NET detects the new files and restarts the application using the new DLLs automatically.
• In ASP, the only type of authentication that you can use is Windows authentication, whereas ASP.NET allows different types of logon and user authentication, including Windows, Passport, and cookies.
• ASP.NET has several features that improve reliability, including automatic application recycling. In addition, ASP.NET includes several performance monitors.

The system administrator may be required to update the configuration files that are part of an ASP.NET application. In addition, security settings and machine configuration files may also need to be updated over time. Finally, configuration files may need to be changed when an update to an application is received.

See Also

See the following topics in the .NET Framework SDK documentation: ASP.NET QuickStart, Creating ASP.NET Web Applications.