The Role of IIS in the Client/Server Relationship

Before delving into the details of building a Web-based application, it might be helpful to review the architectural model of the Web, and the roles of the browser and server in that model.

The User Experience

Sharing information on the Internet is a simple process of a user (or client) using a Web browser such as Internet Explorer (IE) to request a file from a Web server such as IIS.

The Web server sends the browser a response that contains the requested file as well as headers that contain connection information. The Web browser uses the HTML tags in the file to properly format and display the data in the file. A Web browser that displays HTML has the capacity to mimic any user interface.

Static Files Compared to Dynamic Files

If the file that the Web browser receives looks the same as the file that is stored on the Web server, the file is considered to be static content. Static content does not allow for changes based on variables like time or individual user data that is stored in a database.

The following illustration shows the transmission of a static file where the displayed date will never change.

Content can be generated dynamically, either on the side of the Web client (using client-side scripting, DHTML, XML, or other client applications) or on the side of the Web server (using ASP, ASP.NET, COM components, ISAPI, or other server interfaces).

The following illustration shows the transmission of dynamically generated content where the displayed date reflects the date at the time of the request.

The Role of IIS

IIS fulfills the role of the Web server, responding to requests for files from Web clients such as IE, and logging activity.

IIS maintains information about the location of content files, what security identities have access to those files, how content files are separated into applications, and what URLs are mapped to those applications. This information can be configured manually or programmatically by using one of the IIS administration technologies.

IIS can communicate with software such as Microsoft SharePoint, Microsoft Visual Studio.NET, and Web Distributed Authoring and Versioning (WebDAV) to make Web content creation fast and easy. Web content can be created to take advantage of one of the IIS development technologies.