An important challenge for "All-IP" wireless networks is the development of solutions for seamless mobility. A lot of mobility management protocols have been developed to match real-time requirements in these networks. Estimation of the cost, resulting from deploying these protocols, is very important. So far, this cost are estimated by developing a mathematical model for each individual protocol. Until now, there is no generic mathematical model that can be used for a wide range of mobility management protocols. In this paper, such a generic mathematical model is proposed. The parameters of the generic model are chosen to reflect the characteristics of the studied protocols, mobility patterns and network topologies. A case study motivates the selected parameters for Mobile IP version 6 (MIPv6) and includes the given network topology and mobility pattern. The main advantage of the developed generic model is the fast, simple and accurate cost estimation.