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Consensus in Sparse, Mobile Ad-hoc Networks

Lookup NU author(s): Dr Khaled Alekeish, Dr Paul Ezhilchelvan

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Abstract

Consensus is central to several applications including collaborative ones which a wireless ad-hoc network can facilitate for mobile users in terrains with no infrastructure support for communication. We solve the consensus problem in a sparse network in which a node can at times have no other node in its wireless range and useful end-to-end connectivity between nodes can just be a temporary feature that emerges at arbitrary intervals of time for any given node pair. Efficient one-to-many dissemination, essential for consensus, now becomes a challenge: enough number of destinations cannot deliver a multicast unless nodes retain the multicast message for exercising opportunistic forwarding. Seeking to keep storage and bandwidth costs low, we propose two protocols. An eventually relinquishing (<>RC) protocol that does not store messages for long is used for attempting at consensus, and an eventually quiescent (<>QC) one that stops forwarding messages after a while is used for concluding consensus. Use of <>RC protocol poses additional challenges for consensus, when the fraction, (f/n), of nodes that can crash is: (1/4)<=(f/n)<(1/2). Consensus latency and packet overhead are measured through simulations and both decrease considerably even for a modest increase in network density.


Publication metadata

Author(s): Ezhilchelvan P; Alekeish K

Publication type: Report

Series Title: School of Computing Science Technical Report Series

Year: 2010

Pages: 19

Source Publication Date: July 2010

Report Number: 1208

Institution: School of Computing Science, University of Newcastle upon Tyne

Place Published: Newcastle upon Tyne

URL: http://www.cs.ncl.ac.uk/publications/trs/papers/1208.pdf


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