sentences:  The Windows Communication Foundation (WCF) executes managed code and offers enterprise-level services for Web Services solutions on Windows XP and Windows Vista.To support Simple Service Discovery Protocol (SSDP) and WS-Discovery, and for extensible discovery to support other protocols, Windows Vista includes the "Function Discovery" API.Function Discovery serves as an abstraction layer between applications and devices, allowing applications to discover devices by referencing the device's function, rather than by its bus type or the nature of its connection.