Integrated Multicast for Ad Hoc Networks (IMAHN-NSF)

该提案将研究、设计和部署一套主要针对自组织网络的新型组播协议。研究人员认为，由于无线网络固有的广播能力，它非常适合多播通信。提出的组播分组路由和转发协议(IMAHN)的主要贡献可以概括为：(1)设计、评估、原型和部署一套适用于自组织网络的组播路由和分组转发协议；(2)为未来的混合媒体互联网开发一个集成的组播路由解决方案；这包括对提供无缝组播服务的机制的调查、评估、原型和部署。IMAHN将强调以下几个方面：(1)健壮性与效率：许多现有的组播路由方法依赖于路由器的状态来跟踪组播成员。再加上大量的信息交换和缓慢的收敛，使得传统的组播方法在由贫乏(低功率、低存储容量)的主机组成的高度动态的自组织网络(AHN)中无法维持。我们提出了一种新的技术，自适应洪泛，它强调快速和健壮的传输。IMAHN将由一套解决一系列AHN和移动性模式的自适应协议组成。在不断变化的AHN中，冗余广播可能是合适的，而在动态较少的AHN中，将考虑一系列更具带宽效率的组播协议；(2)适应性：主机应该能够(并且将会)在临时、固定基础设施的移动网络和传统有线网络之间自由迁移。为了正常运行--当面对底层基础设施的变化时--主机需要在多个多播机制之间进行即时切换；(3)无限移动性：一些现有的解决方案倾向于离散移动性，在这种移动性中，移动周期与休息周期穿插在一起。另一些则假定同时移动的主机的方向、速度和数量受到一定的限制。相反，我们强调所有网络组件的普遍、无限的移动性；(4)集成多播：AHN的多播解决方案很可能与固定网络的多播解决方案有很大不同(主要原因之一是传输速率的显著差异)。为了为未来的混合媒体互联网提供无缝和集成的组播服务，IMAHN将开发新的机制，实现固定和无线组播解决方案的互操作。

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.