This Article 
   
 Share 
   
 Bibliographic References 
   
 Add to: 
 
Digg
Furl
Spurl
Blink
Simpy
Google
Del.icio.us
Y!MyWeb
 
 Search 
   
Consensus in Sparse, Mobile Ad Hoc Networks
March 2012 (vol. 23 no. 3)
pp. 467-474
Khaled Alekeish, Newcastle University, Newcastle upon Tyne
Paul Ezhilchelvan, Newcastle University, Newcastle upon Tyne
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 (\diamondsuit RC) protocol that does not store messages for long is used for attempting at consensus, and an eventually quiescent (\diamondsuit QC) one that stops forwarding messages after a while is used for concluding consensus. Use of the \diamondsuit RC protocol poses additional challenges for consensus, when the fraction, {f\over n}, of nodes that can crash is {1\over 4} \le {f\over n} < {1\over 2}. Consensus latency and packet overhead are measured through simulations and both decrease considerably even for a modest increase in network density.

[1] M.J. Fischer, N.A. Lynch, and M.S. Paterson, "Impossibility of Distributed Consensus with One Faulty Process," J. ACM, vol. 32, no. 2, pp. 374-382, 1985.
[2] W. Wu, J. Cao, and M. Raynal, "Eventual Clusterer: A Modular Approach to Designing Hierarchical Consensus Protocols in MANETS," IEEE Trans. Parallel and Distributed Systems, vol. 20, no. 6, pp. 753-765, June 2009.
[3] W. Wu, J. Cao, J. Yang, and M. Raynal, "Design and Performance Evaluation of Efficient Consensus Protocols for Mobile Ad Hoc Networks," Computers, vol. 56, no. 8, pp. 1055-1070, Aug. 2007.
[4] G. Chockler, M. Demirbas, S. Gilbert, C. Newport, and T. Nolte, "Consensus and Collision Detectors in Wireless Ad Hoc Networks," Proc. 24th Ann. ACM Symp. Principles of Distributed Computing (PODC), pp. 197-206. 2005.
[5] F. Borran, R. Prakash, and A. Schiper, "Extending Paxos/LastVoting with an Adequate Communication Layer for Wireless Ad Hoc Networks," Proc. IEEE 27th Symp. Reliable Distributed Systems (SRDS), pp. 227-236, 2008.
[6] K. Fall, "A Delay Tolerant Network Architecture for Challenged Internets," Proc. ACM Applications, Technologies, Architectures, and Protocols for Computer Comm. (SIGCOMM), pp. 27-34, Aug. 2003.
[7] Z. Zhang, "Routing in Intermittently Connected Mobile Ad Hoc Networks and Delay Tolerant Networks: Overview and Challenges," IEEE Comm. Surveys and Tutorials, vol. 8, no. 1, pp. 24-37, Mar. 2006.
[8] K. Alekeish and P. Ezhilchelvan, "Consensus in Sparse, Mobile Ad-Hoc Networks" IEEE Trans. Parallel and Distributed Systems, vol. PP, no. 99, p. 1, June 2011.
[9] P. Ezhilchelvan, A. Mostefaoui, and M. Raynal, "Randomized Multivalued Consensus," Proc. Fourth Int'l Symp. Object-Oriented Real-Time Computing (ISORC '01), pp. 195-200, 2001.
[10] C. Ho, K. Obraczka, G. Tsudik, and K. Viswanath, "Flooding for Reliable Multicast in Multi-Hop Ad Hoc Networks," Proc. Third ACM Workshop Discrete Algorithms and Methods for Mobile Computing and Comm. (DIALM), pp. 64-71, 1999.
[11] M.K. Aguilera, W. Chen, and S. Toueg, "On Quiescent Reliable Communication," SIAM J. Computing, vol. 29, no. 6, pp. 2040-2073, 2000.
[12] F. Bonnet, P. Ezhilchelvan, and E. Vollset, "Quiescent Consensus in Mobile Ad-Hoc Networks Using Eventually Storage-Free Broadcasts," Proc. 21st ACM Symp. Applied Computing (SAC), pp. 670-674, 2006.
[13] E.W. Vollset and P.D. Ezhilchelvan, "Design and Performance-Study of Crash-Tolerant Protocols for Broadcasting and Reaching Consensus in MANETS," Proc. IEEE 24th Symp. Reliable Distributed Systems (SRDS), pp. 166-178, 2005.
[14] R. Barr, Z.J. Haas, and R. van Renesse, "JiST: An Efficient Approach to Simulation Using Virtual Machines," Software— Practice and Experience, vol. 35, no. 6, pp. 539-576, 2005.
[15] F. Greve and S. Tixeuil, "Knowledge Connectivity versus Synchrony Requirements for Fault-Tolerant Agreement in Unknown Networks," Proc. IEEE 37th Ann. Int'l Conf. Dependable Systems and Networks (DSN), pp. 82-91, 2007.
[16] D. Cavin, Y. Sasson, and A. Schiper, "Consensus with Unknown Participants or Fundamental Self-Organization," Proc. Third Int'l Conf. Ad Hoc Networks and Wireless (ADHOC-NOW), pp. 135-148, 2004.

Index Terms:
Manet, network density, node connectivity, crash tolerance, consensus, quiescent multicasting, coverage assurance.
Citation:
Khaled Alekeish, Paul Ezhilchelvan, "Consensus in Sparse, Mobile Ad Hoc Networks," IEEE Transactions on Parallel and Distributed Systems, vol. 23, no. 3, pp. 467-474, March 2012, doi:10.1109/TPDS.2011.182
Usage of this product signifies your acceptance of the Terms of Use.