1. Introduction
In recent years, the number of people using mobile terminals has increased. In the future, it is expected that the number of people who use the Internet in outside will increase because it will become easier to access there. Handover is a technique which is used for continuing the communication of the mobile terminals. It is important for the handover technique to maintain communication even if the mobile terminals move between base stations. There are some protocols which support the handover technique. Proxy Mobile IPv6 (PMIPv6) [1] is one of the protocols which is used for performing a network-based handover to switch the communication path of the mobile terminals. However, there is a problem that all communication of the mobile terminals pass through a proxy server called Local Mobility Anchor (LMA).