UPNP

Universal Plug and Play (UPnP) is a family of networking protocols that enables devices on a local network to discover each other and establish functional network services automatically. It is designed for consumer electronics, computers, printers, and other networked devices to work together without manual configuration.

UPnP operates on a device and service model. Devices, called UPnP devices, expose one or more services that define actions and state information. Control points, typically software or other devices, can discover devices and services using the Simple Service Discovery Protocol (SSDP), retrieve device and service descriptions in XML, and invoke actions using the Simple Object Access Protocol (SOAP). State changes and events are communicated via the General Event Notification Architecture (GENA). This architecture supports dynamic addition and removal of devices on the network.

Key features include automatic device discovery, network service control, eventing for state changes, and, in many implementations, NAT traversal through the Internet Gateway Device (IGD) service to map ports automatically. UPnP has been extended with UPnP AV for media sharing and streaming, as well as device type definitions and service templates to cover a wide range of consumer devices.

UPnP is widely used in home networks to enable tasks such as media streaming, printer sharing, gaming, and device interoperation. However, it has faced security concerns due to limited authentication and access control in some implementations, leading to recommendations to disable UPnP on networks where security is a priority.