The Integrated Pipeline is one of the new features of Internet Information Services (IIS) version 7. It allows your HttpModules to participate in all requests, including those for static content, PHP pages and images.
The Classic Pipeline works just like IIS 6.0. All requests pass through the IIS pipeline first, and then if the file extension is mapped to ASP.NET ISAPI extension, then the request is handed to aspnet_isapi.dll and passes through the ASP.NET request pipeline. If the file is static file, ASP or PHP, it is handled by something else.
The following information will guide you on how to change the application pool to use either one of these pipelines.
To begin, launch the Internet Information Services Manager.
Click Start, then Run, then Type: InetMgr.exe , and click ok to launch.
Once displayed, please double-click the server name to expand it.
Click once on Application Pools in the left window pane to display them.
Click once on the application pool you would like to change.
Now, click on Basic Settings… on the right side.
A window will pop up that will give you access to change the Pipeline mode to either Classic or Integrated.