Book Description
An ad hoc network does not require any pre-existing infrastructure or configuration but is formed spontaneously by (possibly mobile) nodes that wish to communicate. Each node in the ad hoc network acts as a router and forwards packets on behalf of other nodes, allowing nodes that are not within wireless range of each other to communicate over multi-hop paths. Example ad hoc network applications include disaster relief scenarios, conference attendees who want to form a network in order to exchange documents, friends involved in a distributed outdoors game, surveillance teams composed of persons or robots exploring a dangerous area, or another planet. Previous efforts to design general-purpose on-demand multicast routing protocols for ad hoc networks have utilized periodic (non-on-demand) mechanisms within some portions of the protocol. The overall on-demand nature of such protocols derives from the fact that significant portions of their operation are active only for active multicast groups. However, the periodic mechanisms within the protocol are responsible for core routing functionality and significantly affect overall protocol performance. My thesis in this dissertation is that on-demand multicast that does not rely on periodic techniques is more efficient and performs better than multicast that utilizes such techniques. To support my thesis statement, in this dissertation I present the design and evaluation of a new multicast protocol, the Adaptive Demand-Driven Multicast Routing protocol (ADMR) for multi-hop wireless ad hoc networks. ADMR uses no periodic control packet network-wide floods, periodic neighbor sensing, or periodic routing table exchanges, and adapts its behavior based on network conditions and application sending pattern, allowing efficient detection of broken links and expiration of routing state that is no longer needed.
