Cost analysis of mobility protocols

Increasing demand for mobility in wireless data network has given rise to various mobility management schemes. Most of the analysis on mobility protocols used Random Waypoint mobility model However, the analysis done earlier ignored some major costs, resulting in an incomplete estimation and used random waypoint model which fails to represent realistic movement pattern. In this paper, we have developed an analytical cost model considering all possible costs related to mobility management, and have used city section mobility model, a realistic mobility model, to compute the total costs of two mobility protocols: HIMPv6 and SIGMA. We have defined two novel performance metrics, normalized overhead and efficiency, for mobility protocols based on the signaling costs and used them to evaluate the performance of SIGMA and HMIPv6 protocols varying network size, mobility rate and traffic rate. Results show that the total cost of SIGMA is much less than HMIPv6 due to the higher cost of packet tunneling, even though the mobility signaling cost of SIGMA is higher than HMIPv6. Moreover, mobility signaling costs of both the protocols using city model and random waypoint model are found to be much different, demonstrating the fact that random waypoint model cannot be used as an approximation to a realistic scenario. The analytical framework presented in this paper can be used by the network professionals to estimate amount of load on the network due to mobility protocols and compare them based on the proposed performance metrics to select the best protocol.