Editing Universal Plug and Play (section)

===Discovery===
Once a device has established an IP address, the next step in UPnP networking is discovery. The UPnP discovery protocol is known as the [[Simple Service Discovery Protocol]] (SSDP). When a device is added to the network, SSDP allows that device to advertise its services to control points on the network. This is achieved by sending SSDP alive messages. When a control point is added to the network, SSDP allows that control point to actively search for devices of interest on the network or listen passively to the SSDP alive messages of devices. The fundamental exchange is a discovery message containing a few essential specifics about the device or one of its services, for example, its type, identifier, and a pointer (network location) to more detailed information.