Provisioning multicast QoS for WDM-based optical wireless networks

Wavelength division multiplexing (WDM)-based optical technique is becoming the right choice for the next-generation Internet infrastructure to transport high-speed Internet Protocol traffic. Today, wireless asynchronous transfer mode (WATM) network plays the leading role; undoubtedly it will be replaced with wireless WDM (WWDM) network to provide higher quality of service for mobile users. In addition many conventional and emerging applications, such as teleconferencing and distributed games, require multicasting increasingly. Many efforts to support multicasting for WATM networks have been offered, yet there are rarely addressed on WWDM networks. Moreover, conventional operations to set up and tear down optical connections in WDM networks are unable to apply directly to WWDM networks. User's mobility may make the operating optical-multicast-tree to change into very inefficient. The tree may expand and consume excessive resources, and even lost connection due to violating the associated QoS constraints. In this paper, a Constrained Optical Tree Migration Scheme (COTMS) is proposed to support real-time multicast services for WWDM networks. COTMS efficiently deals with the constrained tree migration problem and adapts easily to the operations of WDM. Simulation results reveal that COTMS can markedly reduce the resources used by per optical tree, thus achieving both low handoff-dropping/join-blocking rate and high-resource utilization. Moreover, COTMS is also suitable for ad-hoc networks with multiple different frequencies for multicast routing. (C) 2004 Elsevier B.V.. All rights reserved.