Integrated Multicast for Ad Hoc Networks (IMAHN-NSF)

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This proposal will investigate, design and deploy a suite of novelmulticast protocols aimed primarily at ad hoc networks. The investigatorsmaintain that, due to the inherent broadcast capability, wireless networksare well suited for multicast communication. The contributions of theproposed suite of multicast packet routing and forwarding protocols (IMAHN)can be summarized as follows: (1) design, evaluation, prototyping anddeployment of a suite of multicast routing and packet forwarding protocolsfor ad hoc networks, and (2) development of an integrated multicastrouting solution for the mixed-media internetwork of the future; thisincludes investigation, evaluation, prototyping, and deployment ofmechanisms providing seamless multicast service.IMAHN will emphasize the following: (1) robustness vs efficiency: manyexisting multicast routing approaches rely on state in routers to keeptrack of multicast group members. This, coupled with the high volume ofrouting information exchanges and slow convergence, makes traditionalmulticast approaches untenable in highly dynamic ad hoc networks (AHNs)composed of anemic (low-power, low storage capacity) hosts. We propose anew technique, adaptive flooding, that stresses rapid and robust delivery.IMAHN will consist of a suite of adaptive protocols addressing a range ofAHNs and mobility patterns. In constantly changing AHNs, redundantbroadcasting may be appropriate, while, in less dynamic AHNs, a range ofmore bandwidth-efficient multicast protocols will be considered; (2)adaptability: hosts should be able to (and will) migrate freely among adhoc, fixed-infrastructure mobile, and traditional wired networks. In orderto function appropriately -- when faced with changes in the underlyinginfrastructure -- hosts need switch on-the-fly among multiple multicastmechanisms; (3) unlimited mobility: some existing solutions are gearedtowards discrete mobility where periods of movement are interspersed withperiods of rest. Others assume certain limits on direction, speed andnumber of simultaneously moving hosts. In contrast, we stress universal,unlimited mobility of all network components; (4) integrated multicast:multicast solutions for AHNs will most likely differ substantially fromthose for fixed networks (one of the main reasons is the marked differencein transmission rates). In order to offer seamless and integrated multicastservice for the mixed-media internetwork of the future, IMAHN will developnovel mechanisms for inter-operation of fixed and wireless multicastsolutions.