DESIGN OF GLOBAL ROAMING PROCEDURE AMONG INDEPENDENTLY OPERATED MOBILE IP NETWORKS

摘要

Recently, several types of mobile data networks, such as cellular phone based data networks and wireless LAN based hot spot networks are available. Accordingly, it becomes common that one terminal has multiple subscriptions to different mobile networks and switches over among those networks. In such an environment, it is required that multiple networks coordinate with each other in such a way that communication continues even after switching from a low speed cellular network to a high speed hot spot network. Currently, there are many researches studied on this global roaming among networks, but most of them focus only on the radio transmission level. However, it is considered that different networks are operated independently also in a network control level, and therefore a global roaming procedure must consider that there could be a difference between each networks operation scheme. In this paper, we discuss a global roaming procedure for independently operated Mobile IP networks. Our procedure exploits the co-located care-of address in Mobile IP and realizes the global roaming without any modification to the Mobile IP network elements, such as home or foreign agents.