IIS 7.0 is made up of several components that form the web server internal core engine. These components include protocol listeners, services such as the w3svc service and the WAS service, protocol adapters, and many more core components. This section will present an overview of some of the protocols and services that handle request processing inside IIS 7.0.
Protocol listeners are services in which each service is configured to listen and process a specific protocol request coming from the network on which the machine hosting the web server resides. For instance, one of the listeners installed on a Windows machine keeps on waiting and listening for any web request arriving on the machine. There are additional listeners also present to listen to other, different protocols. When a request is received by a listener, it forwards it to IIS 7.0 to be processed. Once a request is processed by IIS 7.0, the response generated is sent back to the protocol listener that originally sent the request. Finally, the response is handed back to the requestor.
An example of a protocol listener is the HTTP listener called Hyper Text Protocol Stack. This is the main protocol listener for all HTTP requests arriving on a Windows machine. When an HTTP request is first received by Windows Vista or Windows Server 2008, the initial handling is actually performed by the kernel-mode HTTP driver: http.sys.
In IIS ...