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 UPnP-based 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.