ASP.NET Site Navigation
ASP.NET site navigation is a set of classes that enable you to provide a consistent way for users to navigate your site. As your site grows, and as you move pages around in the site, it quickly becomes difficult to manage all of the links. ASP.NET site navigation enables you to store links to all of your pages in a central location, and render those links in lists or navigation menus on each page by including a SiteMapDataSource control to read site information and navigation Web server control such as the TreeView, or Menu controls to display site information.
ASP.NET site navigation consists primarily of site map providers, which communicate with the site map data source, and the classes that expose the functionality of the site map providers. For example, the default ASP.NET site map provider obtains site map data from an XML file named Web.sitemap, and communicates that data to the SiteMapPath Web server control directly.