Adaptive integrated approach to group communications in multi-hop ad-hoc networks

In recent years, Mobile Ad Hoc networks (MANETs) have been extensively studied as an alternative to infrastructure networks because of their ease of deployment. The targeted environments for ad hoc networks are typically inhospitable regions where it is difficult to set up infrastructure or environments where the existing infrastructure has collapsed temporarily or permanently. MANETs maintain dynamic interconnection between mobile users through multi-hopping. MANET nodes may be highly mobile or stationary and may vary widely in terms of their capabilities and applications. All these features pose serious challenges to routing.; Since group-oriented services are one of the key classes of applications targeted by MANETs, several multicast protocols have been proposed by the ad-hoc network community. In this dissertation, we propose techniques to provide seamless, integrated multicast service whereby a single multicast group can span different network types (e.g., fixed, fixed mobile, and different types of MANETs). Our goal is to develop an integrated, adaptive framework whereby nodes can communicate across various ad-hoc clouds running different multicast protocols. This will allow a given host to partake in multicast communication regardless of the underlying routing protocol and may require hosts to adaptively switch routing mechanisms as they move from one network to another. To our knowledge, there is little or no experience in the network research community in multicast protocol interoperation or adaptation (albeit, some proposals have been floated in the IETF) [1-3].; As a first step, we have studied both mesh based and tree based protocols and evaluated their performance relative to flooding. Our study shows that, although these protocols perform well under very specific scenarios of mobility, traffic load and network conditions no single protocol is optimal in all scenarios. In particular, we investigate the performance of On-demand Multicast Routing Protocol (ODMRP) and Multicast Ad Hoc On-demand Distance Vector (MAODV) and compare the performance with baseline flooding. Based on an extensive comparative study we also propose two flooding variations i.e. scoped flooding and hyper flooding as means to reduce overhead and increase reliability respectively. An important contribution from this initial study was a qualitative and quantitative comparison of mesh and tree based protocols and the proposed flooding variations. (Abstract shortened by UMI.)...