Load balancing policies for multiple home agents mobile IP networks

Abstract

In a continuously expanding mobile and wireless networking environment, Mobile IP is the preferred standard responsible for providing Internet connectivity to roaming mobile nodes. Under certain conditions of traffic, such as in Mobile IP networks supporting multimedia applications, overhead can cause delays at the mobility agents, i.e. foreign and home agents. While the Mobile IP standard does not exclude the possibility of using multiple home agents, it does not impose any particular model either; therefore using only one home agent in a classic home network configuration can significantly bottleneck the IP data packet streams destined to the mobile nodes. In this paper we consider a multiple home agent extension of the Mobile IP protocol. We develop a simulator in order to evaluate its performance, and we compare several results obtained during a comprehensive simulation study of the system. We introduce a realistic double-threshold load balancing policy, and compare its behaviour with that of other dynamic/static policies. Using simulation, we also analyze the impact of modifying the number of load balanced home agents on the overall system performance. The results show that some load balancing policies, expected to perform better than others, occasionally have an opposite behavior The behaviour proves out to be highly dependent on the degree of burstiness of the traffic. Under an unbalanced traffic configuration, the proposed double threshold policy performs better than the other static, dynamic load balancing schemes considered in our study.