Global roaming among Mobile IP networks operated by different administrative domains. Support of incoming/outgoing calls for mobile nodes having private addresses

Recently, various mobile networks have been provided for mobile Internet services, and Mobile IP has become a key protocol for location/mobility management for mobile nodes. Although Mobile IP is originally intended to support the mobility of global IP addresses, there are considerable needs for supporting private addresses for mobile nodes due to the rapid growth of mobile terminals and the lack of global addresses. In addition, for global communications, it is also required to realize mobility among several mobile networks operated by different administrative domains. In this paper, we propose an approach to support global roaming among different mobile networks where Mobile IP is used for mobility management of mobile nodes with private addresses in a closed domain. In order to realize global roaming among different mobile IP networks, we have introduced global roaming agent (GRA) for each mobile network. This paper presents detailed roaming procedures using GRA. Implementation and performance evaluation results of our proposed method are also given.