UPnP

(Universal Plug aNd Play) A family of protocols that enables data transfer between computers, mobile devices and A/V equipment. Introduced in 1999 by the UPnP Forum (www.upnp.org), UPnP provides automatic discovery of devices in an IP network (see SSDP). It is widely used to stream music to playback devices (see DLNA).

Supporting quality of service, which prioritizes transmission (see QoS), UPnP is also used in security camera, lighting, heating and air conditioning applications.

Automatic IP Assignment
UPnP can assign an IP address to a device if it does not already have one and no DHCP server is available in the network to assign one (see DHCP and IP address).

UPnP vs. Zeroconf
UPnP is similar to Zeroconf, a zero configuration technology implemented in Apple's Bonjour software and by others. UPnP and Zeroconf both provide service discovery and IP assignment but use different protocols (see Zeroconf and link-local address).

Port Forwarding (Port Mapping)
UPnP has been used to open ports in a router to let a party from the outside world contact a user inside the network. For example, opening ports for voice and video calling facilitates two-way communications no matter which side initiates the call. See TCP/IP port.

UPnP Is Not PnP
Although related in concept because they both provide automatic configuration of devices, UPnP is not the same as PnP (see Plug and Play).