Design and analysis of optimal multi-level hierarchical mobile IPv6 networks

Hierarchical Mobile IPv6 (HMIPv6) is an enhanced version of Mobile IPv6 designed to reduce signaling overhead and to support seamless handoff in IP-based wireless/mobile networks. To support more scalable services, HMIPv6 networks can be organized as the form of a multi-level hierarchy architecture (i.e., tree structure). However, since multi-level HMIPv6 networks incur additional packet processing overhead at multiple mobility agents, it is important to find the optimal hierarchy level to minimize the total cost, which consists of the location update cost and the packet delivery cost. In this paper, we investigate this problem, namely the design of an optimal multi-level HMIPv6 (OM-HMIPv6) network. To accomplish this, we design a function to represent the location update cost and the packet delivery cost in multi-level HMIPv6 networks. Based on these formulated cost functions, we calculate the optimal hierarchy level in multi-level HMIPv6 networks, in order to minimize the total cost. In addition, we investigate the effects of the session-to-mobility ratio (SMR) on the total cost and the optimal hierarchy. The numerical results, which show various relationships among the network size, optimal hierarchy, and SMR, can be utilized to design an optimal HMIPv6 network. In addition, the analytical results are validated by comprehensive simulations.