A dynamical redirection approach to enhancing Mobile IP with fault tolerance in cellular systems

The paper investigates the reliability of Mobile IP in a cellular system. To support the node mobility, a lot of mobility agents are deployed in the packet network of a cellular system to retain the continuous network connectivity while mobile nodes move their locations. If a mobility agent fails, the mobile nodes under its coverage area will be affected. The network connectivity of these mobile nodes will be disrupted. The main goal of this paper is to present an efficient approach to tolerating the failures of mobile agents. Once failures occur in a mobility agent, its in-progress and new-arrival workload can be redirected to other mobility agents. The mobile nodes under the mobility agent´s coverage area do not lose their data executive ability. The overhead of the proposed fault-tolerant approach is also measured in terms of the performance degradation on other mobility agents by using an M/G/m/m queueing mode. The analytic results show that the performance degradation is very low if the workloads of the faulty mobility agent are not too heavy.