Abstract
In this paper, the main issues of wireless LAN Emulation over ATM networks are addressed and investigated. One of the most important issues is to support the transparent services for the mobile terminals. We show that the conventional LAN Emulation service, defined by the ATM Forum, for the legacy LANs (Ethemet/FDDUToken ring) is not efficient enough to handle the handoff of the wireless LANs. The communication path will be elongated as the mobile terminals move into the neighboring cells. This is undesirable since an elongated path not only consumes too much bandwidth but also introduces additional delay. To overcome this problem, a seamless handoff scheme is proposed for the ATM-based wireless LANs. This scheme not only meets the basic handoff requirements (data continuity and transparency), but also offers a shorter path. A path migration scheme is also suggested to migrate an inefficient path to a better one, if any. The effectiveness of the proposed handoff/migration schemes to the wireless LAN Emulation service is demonstrated via simulation. Simulation results show that the proposed handofUmigration schemes perform much better than the conventional LAN Emulation scheme in terms of the average number of hops consumed per virtual connection.