A mobility-based load control scheme at mobility anchor point in Hierarchical Mobile IPv6 networks

In Hierarchical Mobile IPv6 (HMIPv6) networks, the mobility anchor point (MAP) handles binding update (BU) procedures locally to reduce signaling overhead for mobility. However, as the number of mobile nodes (MNs) handled by the MAP increases, the MAP suffers from the overhead not only to handle signaling traffic (e.g., binding update) but also to process data tunneling traffic. Therefore, it is important to control the number of MNs serviced by the MAP, in order to mitigate the burden of the MAP that results in higher latency. In this paper, we propose a mobility-based load control scheme, which consists of two sub-algorithms: (1) threshold-based admission control algorithm and (2) session-to-mobility ratio (SMR) based replacement algorithm. Here the SMR is defined as a ratio of the session arrival rate to the handoff rate. When the number of MNs at a MAP reaches to the full capacity, the MAP replaces an existing MN at the MAP, whose SMR is high, with an MN that just requests binding update. The replaced MN is redirected to its home agent. We analyze the proposed load control scheme using the Markov chain model in terms of the new MN blocking probability and the ongoing MN dropping probability. By combining the threshold-based admission control with the SMR-based replacement, the above probabilities are lowered significantly compared to the threshold-based admission control alone.