Path Set Selection in Mobile Ad Hoc Networks
Topological changes in mobile ad hoc networks frequently render routing paths unusable. Such recurrent path failures have detrimental effects on the network ability to support QoS-driven services. A promising technique for addressing this problem is to use multiple redundant paths between the source and the destination. However,while multipath routing algorithms can tolerate network failures well,their failure resilience only holds if the paths are selected judiciously. In particular,the correlation between the failures of the paths in a redundant path set should be as small as possible. However,selecting an optimal path set is an NPcomplete problem. Heuristic solutions proposed in the literature are either too complex to be performed in real-time, or too ineffective,or both. This paper proposes a multipath routing algorithm,called Disjoint Pathset Selection Protocol (DPSP),based on a novel heuristic that, in nearly linear time on average,pic ks a set of highly reliable paths. The convergence to a highly reliable path set is very fast, and the protocol provides flexibility in path selection and routing algorithm. Furthermore,DPSP is suitable for real-time execution,with nearly no message exchange overhead and with minimal additional storage requirements. This paper presents evidence that multipath routing can mask a substantial number of failures in the network compared to single path routing protocols,and that the selection of paths according to DPSP can be beneficial for mobile ad hoc networks, since it dramatically reduces the rate of route discoveries.