Interconnecting multiple home networks services

Universal Plug and Play (UPnP) is a set of protocols for automatic service discovery in a Local Area Network (LAN). UPnP is suitable for home networking environments, where consumers, e.g., can buy a new device, plug it into the network and the device automatically configures itself in order to access the resources of the network. UPnP can be used only in a single LAN because the UPnP protocols use link-local multicast to announce their presence and there is no global Internet-wide multicast backbone available for multicast service discovery. Consequently, the devices and services of one LAN will not be available to another LAN. In this paper we describe a solution for connecting multiple home networks and their UPnPbased services together over the public Internet, without relying on global multicast. We have implemented the solution and tested it using UPnP capable devices such as Nokia mobile phones and a PDA. We discuss the security of the system, e.g., how firewall rules can be set up in the gateway to allow only authorized hosts to access the devices and services.