What is pipeline mode?
Pipeline mode refers to how a Web server processes client requests. IIS 7 offers two pipeline modes. Integrated pipeline mode handles all requests through a unified pipeline because of the integration of ASP.NET's runtime with the Web server. IIS 7's classic mode behaves in the same manner as IIS 6, using two pipelines to process requests--one for native-code application components and the other for managed code application components.
For information on issues around migrating legacy code, see Migration Issues with IIS 7's Integrated Pipeline Mode.
For information on changing your pipeline mode, see Changing Pipeline Mode on Your Windows IIS 7 Hosting Account.