Application pools in IIS (internet information service) can run in one of two modes
1)Integrated 2)classic
Web server will process the request based on the selected mode. if you selected integrated mode , then iis will use the new request processing pipelines of iis and asp.net. if you selected classic mode then server will route request processing pipelines of iis 6.0 through aspnet_isapi.
Thanks & Regards G.Renganathan Nothing is mine ,Everything is yours!!!