1 IIS picks up the request 2 searches for server extensions. 3 IIS maps the request to the aspnet_isapi.dll file.(for aspx file) 4 The ASP.NET worker process initializes the HttpPipeline. 5 The HttpPipeline has HttpRuntime, HttpWorkerRequest, HttpApplicationFactory, etc. 6 If an HttpApplication object doesn’t exist, it creates a new one or picks up one from the HttpApplicationFactory’s pool of HttpApplication objects 7 worker process calls the HttpRuntime.ProcessRequest() . 8 The HttpRuntime creates the HttpContext 9 calls the HttpApplicationFactory to create web page 10 The HttpApplication finds type of incoming request and invokes the appropriate 11 PageHandlerFactory. It searches the <httpHandlers> section of the machine.config file. 12 The PageHandlerFactory creates an instance of the page . 13 The page instance is returned to the HttpRuntime with the help of the HttpApplicationFactory.