DESIGN OF GLOBAL ROAMING PROCEDUREAMONG INDEPENDENTLY OPERATED MOBILE IP NETWORKS

摘要

Recently, several types of mobile datanetworks, such as cellular phone based data networks andwireless LAN based hot spot networks are available.Accordingly, it becomes common that one terminal hasmultiple subscriptions to different mobile networks andswitches over among those networks. In such anenvironment, it is required that multiple networkscoordinate with each other in such a way thatcommunication continues even after switching from a lowspeed cellular network to a high speed hot spot network.Currently, there are many researches studied on thisglobal roaming among networks, but most of them focusonly on the radio transmission level. However, it isconsidered that different networks are operatedindependently also in a network control level, andtherefore a global roaming procedure must consider thatthere could be a difference between each networksoperation scheme. In this paper, we discuss a globalroaming procedure for independently operated Mobile IPnetworks. Our procedure exploits the co-located care-ofaddress in Mobile IP and realizes the global roamingwithout any modification to the Mobile IP networkelements, such as home or foreign agents.