ASP.NET System.Web.SiteMapProvider class that provides a common base class for all site map data providers, and a way for developers to implement custom site map data providers that can be used with the ASP.NET site map infrastructure as persistent stores for SiteMap objects.
The StaticSiteMapProvider and XmlSiteMapProvider classes represent the default implementations of the abstract SiteMapProvider class. The XmlSiteMapProvider uses an XML file named Web.sitemap to store site map data.
The SiteMapProvider class supports the concept of a site map provider hierarchy, by declaring the RootProvider and ParentProvider properties. A SiteMapProvider can be a child or parent of another provider. This enables scenarios where different content areas of a site are owned or implemented by different development groups that maintain their own site maps and site map providers.
http://msdn.microsoft.com/en-us/library/system.web.sitemapprovider.aspx