Consideration of Network Selection Criteria on IP Mobility Communications Quality by Real-Time Status and/or Statistical Information

In IP mobility communications, handoff is one of critical points degrading mobile communications quality. To solve this problem, many network selection methods have been proposed. We also proposed a network selection method in handoff and multi-homing to improve IP mobility communications quality. To select the best network interface or communication medium, it is required to obtain QoS criteria such as transmission delay time and packet loss ratio. The mobile node itself may measure real-time network status to obtain the criteria, or the mobile node may obtain statistical information stored in any database on the Internet. Though the criteria collection way affects much on network selection, it is not discussed in detail in the existing research. The purpose of this paper is to consider the difference types of network selection criteria from the viewpoint of effects on IP mobility communications quality. For this purpose, we first designed and implemented two prototype systems to obtain the different types of the criteria. One is a function to measure real-time network status in a mobile node itself. The other one is to obtain the stored statistical information in the database on the Internet. Next, we compare the two kinds of criteria by some field experiments. For the experiments, we also implemented a prototype system using both functions in our proposed IP mobility architecture. Through the experimental evaluations, we showed quantitative comparison of two types of network selection criteria by satisfaction ratio of QoS required by some applications.