The term Plug-and-Play (PnP) has various meanings. In the broad sense it is just auto-configuration where one just plugs in a device and it configures itself. With the addition of Device Plug and Play (PnP) capabilities to the operating system it became a great deal easier to setup, configure, and add peripherals to a PC. Universal Plug and Play (UPnP) extends this simplicity to include the entire network, enabling discovery and control of devices, including networked devices and services, such as network-attached printers, Internet gateways, and consumer electronics equipment.
UPnP is more than just a simple extension of the Plug and Play peripheral model. It is designed to support zero-configuration, "invisible" networking, and automatic discovery for a breadth of device categories from a wide range of vendors. With UPnP, a device can dynamically join a network, obtain an IP address, convey its capabilities, and learn about the presence and capabilities of other devices—all automatically; truly enabling zero configuration networks. Devices can subsequently communicate with each other directly; thereby further enabling peer to peer networking.
The varieties of device types that can benefit from a UPnP enabled network are large and include intelligent appliances, wireless devices, and PCs of all form factors. The scope of UPnP is large enough to encompass many existing, as well as new and exciting scenarios including home automation, printing and imaging, audio/video entertainment, kitchen appliances, automobile networks, and proximity networks in public venues.
UPnP uses standard TCP/IP and Internet protocols, enabling it to seamlessly fit into existing networks. Using these standardized protocols allows UPnP to benefit from a wealth of experience and knowledge, and makes interoperability an inherent feature. UPnP technology is broad in scope in that it targets home networks, proximity networks, and networks in small businesses and commercial buildings. It enables data communication between any two devices under the command of any control device on the network. UPnP technology is independent of any particular operating system, programming language, or physical medium.