UBIQUITOUS NETWORKING SERVER Masugi Inoue 1 , Mikio Hasegawa 1 , Nobuo Ryoki 1 , and Hiroyuki Morikawa 2,1 Abstract A ubiquitous networking server that enables cross-device as well as cross-network mobility with a location sensing system for context-aware seamless network services is introduced. The context includes the user’s presence, position of the user and neighboring devices, network interfaces at- tached to the mobile terminal, availability and available bandwidth of each network, priority in selecting networks, capabilities of the mobile terminal and devices, and installed applications. By integrating these technologies into one packaged system, communication can be initiated in a style that the recipient prefers and connections can be seamlessly handed over from one network to an- other and from one terminal to another. The system allows users to enjoy communicating without being concerned about their positions and the availability and performance specifications of indi- vidual networks and neighboring devices. 1. Introduction In order to create networking technologies that allow users to access the network without being aware of individual networks and devices, we had been developing three separate technologies for cross-network handovers [1], cross-device handovers [2], and a location-sensing platform [3]. Cross-network handover was enabled with a seamless networking platform called MIRAI [4] in which a MIRAI agent provides functions such as location update, paging, and handover manage- ment necessary in heterogeneous networks. Cross-device handover was provided by a service mo- bility proxy (SMP), which switches a connection from one device to another. The previous experi- mental system of cross-network handover was demonstrated at Ubicomp 2004 [1]. Then, we came to integrate those three technologies into one packaged system to provide users with context-based cross-network and cross-device mobility. 2. Design and Implementation We integrated the server functions offered by the MIRAI agent and the SMP by logically re- organizing the software and adding new features to make one functional entity, creating a ubiqui- tous networking server. The client functions of the two systems were also integrated. The ubiquitous networking server is designed to be placed at the entrance of a home or enterprise network (Fig. 1). A mobile phone and a mobile terminal comprise a PAN that moves outside and inside the local network. The PAN is always connected with the ubiquitous networking server through a basic access network (BAN), which is a favorable network selected by each user. The signaling path is shown as the green line, and 3G is used as the BAN. The ubiquitous networking server forwards packets to the PAN through a network, chosen for the position of the PAN, using 1 Mobile Networking Group, National Institute of Information and Communications Technology, 3-4 Hikarino-oka, Yokosuka, Kanagawa, 239-0847 Japan 2 Graduate School of Frontier Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8656 Japan 81