Migrating constrained optical tree in wireless WDM systems

As WDM-based optical networks are becoming the right choice for the next-generation Internet networks to transport high-speed IP traffic, the leading role of wireless ATM (WATM) networks will be undoubtedly replaced with wireless WDM (WWDM) networks for providing high quality of services to mobile users. Meanwhile, multicasting has played an increasingly important role in many conventional and emerging applications, such as teleconferencing and distributed games. In this paper, a constrained optical tree migration scheme (COTMS) is proposed to support multicast services in WWDM networks. COTMS is an enhancement of our previous work, called CTMS, for adapting to the characteristic of WDM-based backbone networks. CTMS can properly deal with the constrained tree migration problem for generic wireless networks, and COTMS inherits the efficiencies of CTMS entirely. Simulation results show that COTMS can markedly reduce the resources used per multicast tree, thus achieving both low handoff-dropping/join-blocking rate and high resource utilization. More importantly, we demonstrate how COTMS incorporating crossover optical switch discovery can be used to support real-time traffic for heterogeneous (i.e., unicast and multicast) connections in a uniform and unified manner. The proposed scheme is also suitable for routing over fully mobile (ad hoc) networks in which multiple frequencies are used for data communications.