The SAP Enterprise Portal supports navigation between various types of portal content. For example, a Web Dynpro application can navigate to the portal content as well as to another Web Dynpro application that is set up differently. Portal content can be, for example, a BSP or an ITS application.
Class IF_WD_APPLICATION provides method GET_CLIENT_ENVIRONMENT, which you can use to determine the client environment and find out whether the portal is active.
As well as being object-based, page navigation can be absolute or relative.