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Algorithms for Prefix Continuity in IPv6 Ad Hoc Networks

Ad hoc networks are formed by the spontaneous collaboration of wireless nodes when no networking infrastructure is available. When communication to the Internet is desired, one or more nodes must act as gateways for the ad hoc network. In this case, global addressing of ad hoc nodes is required. This article presents and evaluates three algorithms which can be used by an ad hoc node to dynamically select a gateway and create an associated IPv6 global address. The core of our proposal is the concept of prefix continuity. By building and maintaining a forest of logical spanning trees, our proposal ensures that there exists, between a node A and its gateway G, a path of nodes such that each node on this path uses the same prefix P as the node A and its gateway G. This concept results in an organized ad hoc network, in the sense that sub-networks (with respect to prefixes) are automatically created and dynamically maintained when multiple gateways are available. Moreover, the concept of prefix continuity ensures that each sub-network forms a connected graph of nodes which all use an identical prefix. In contrast to traditional wired networks, this feature is not trivial in ad hoc networks.

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