Universal Plug and Play (UPnP)

See also plug and play , an earlier, proprietary Microsoft approach.

Universal Plug and Play (UPnP) is a standard that uses Internet and Web protocol s to enable devices such as PCs, peripherals, intelligent appliances, and wireless devices to be plugged into a network and automatically know about each other. With UPnP, when a user plugs a device into the network, the device will configure itself, acquire a TCP/IP address, and use a discovery protocol based on the Internet's Hypertext Transfer Protocol ( HTTP ) to announce its presence on the network to other devices. For instance, if you had a camera and a printer connected to the network and needed to print out a photograph, you could press a button on the camera and have the camera send a "discover" request asking if there were any printers on the network. The printer would identify itself and send its location in the form of a universal resource locator ( URL ).

The camera and printer would use Extensible Markup Language ( XML ) to establish a common language, or "protocol negotiation", to talk to each other and determine capabilities. Once a common language was established, the camera would control the printer and print the photograph you selected. Microsoft, one of 29 companies sponsoring UPnP, hopes that UPnP will make it as easy to plug a device or appliance into a home or small business data network as it is to plug a lamp into an electrical outlet.

Universal Plug and Play is an open industry standard that Microsoft, a leading promoter of the standard, describes as "seamless proximity networking" that provides "standardization on the wire rather than in the devices," using existing Internet standards.