Mobile IP route optimization method for next‐generation mobile networks

Abstract Mobile IP has gained attention as a technology that can provide mobility to universal users independently of the access network. The introduction of Mobile IP in mobile core networks is currently under investigation. This paper discusses route optimization methods when Mobile IP technology is applied to mobile core networks. More specifically, it discusses means of resolving the “Triangle Routing” problem, which occurs when communications from a correspondent node to a mobile node must be routed through a Home Agent (HA). This paper first describes the conventional route optimization method being investigated by the Internet Engineering Task Force (IETF) and indicates problems with that method. It then proposes a new Mobile IP Border Gateway (MBG) method for solving the problems of the conventional method. The MBG method enables packets that arrive from another network to be directly received at the mobile node by having a Border Gateway router maintain Binding Information consisting of the care‐of address and home address that were originally being maintained by the Home Agent for the communicating node. This paper also shows that introducing the MBG method enables the mean route length within the network to be shortened and the traffic volume routed through the Home Agent to be reduced. Finally, it shows methods of reducing the burden of registering Binding Information at the Mobile IP Border Gateway and indicates the applicability of the MBG method to large‐scale mobile communications networks. © 2002 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 86(2): 31–41, 2003; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/ecja.1151