Analysis of Link Reversal Routing Algorithms for Mobile Ad Hoc Networks
Résumé
Link reversal (LR) algorithms provide a simple mechanisme for routing in communication networks whose topology is frequently changing, such as in mobile and ad hoc networks. A LR algorithm routes by imposing a direction on each network link such that the resulting graph is destination oriented (DAG). Whenever a node loses routes to the destination, is reacts by reversing some (or all) of its incident links. This survey presents the worst-case performance analysis of LR algorithms from the excellent work of Costas Busch and Srikanta Tirthapura (SIAM J. on Computing, 35(2):305- 326, 2005). The LR algorithms are studied in terms of work (number of node reversals) and time needed until the algorithm stabilizes to a state in which all the routes are reestablished. The full reversal algorithm and the partial reversal algorithm are considered. • The full reversal algorithm requires O(n2) work and time, where n is the number of nodes that have lost routes to the destination. This bound is tight in the worst case. • The partial reversal algorithm requires O(na*r + n2) work and time, where a*r is a non-negative integral function of the initial state of the network. Further, the partial reversal algorithm requires (na*r + n2) work and time. • There is an inherent lower bound on the worst-case performance of LR algorithms: \Omega(n2). Therefore, surprisingly, the full reversal algorithm is asymptotically optimal in the worst-case, while the partial reversal algorithm is not; since a*r can be arbitrarily larger than n.
Origine : Fichiers produits par l'(les) auteur(s)