Adaptive Mode Switching for Internetworking of MANET and WLAN Based on HMIPv6∗

Abstract. For extending of hot-spot of wireless LAN (WLAN), [1] proposes in-ternetworking scheme between WLAN and mobile ad-hoc network (MANET), which employ the same layer-2 protocol with different mode. Compared to in-ternetworking schemes between UMTS (Universal Mobile Telecommunications Systems) and WLAN [3-4], the scheme from [1] has relatively low overhead and latencies because WLAN and MANET are physically and logically similar to each other. However, the mode switching algorithm proposed in [1] for internetworking only considers signal strength and determines handoff, and mobile nodes following a zigzag course in pollution area may frequently per-form handoff at short intervals. Furthermore, [1] employs mobile IPv6 (MIPv6) at base, which brings still high delay on handoff and overhead due to signal message exchange. In this paper, we present optimized internetworking scheme between WLAN and MANET, modified from [1]. To settle ping-pong handoff, we propose adaptive mode switching algorithm. HMIPv6 is employed for IP connectivity and mobility service in WLAN, which solves some shortcomings, such as high handoff overhead and vulnerable security from MIPv6. For routing in MANET, OLSR is employed, which operates with current IP protocol com-patibly with no change or modification. The proposed internetworking scheme based on adaptive mode switching algorithm shows better performance than scheme from [1]. 1