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On Multicopy Opportunistic Forwarding Protocols in Nondeterministic Delay Tolerant Networks
June 2012 (vol. 23 no. 6)
pp. 1121-1128
Cong Liu, Sun Yat-sen University, Guangzhou
Jie Wu, Temple University, Philadelphia
Delay Tolerant Networks (DTNs) are characterized by nondeterministic mobility and connectivity. Message routing in DTNs usually employs a multicopy forwarding scheme. To avoid the cost associated with flooding, much effort has been focused on opportunistic forwarding, which aims to reduce the cost of forwarding while retaining high routing performance by forwarding messages only to nodes that have high delivery probabilities. This paper presents two multicopy forwarding protocols, called optimal opportunistic forwarding (OOF) and OOF-, which maximize the expected delivery rate and minimize the expected delay, respectively, while requiring that the number of forwardings per message does not exceed a certain threshold. Our contributions in this paper are summarized as follows: We apply the optimal stopping rule in the multicopy opportunistic forwarding protocol. Specifically, we propose two optimal opportunistic forwarding metrics to maximize delivery probability and minimize delay, respectively, with a fixed number of copies and within a given time-to-live. We implement and evaluate OOF and OOF- as well as several other representative forwarding protocols, i.e., Epidemic, Spray-and-wait, {\rm MaxProp}^\ast, and Delegation. We perform trace-driven simulations using both real and synthetic traces. Simulation results show that, in the traces where nodes have regular intermeeting times, the delivery rates of OOF and OOF- can be 30 percent greater than the compared routing protocols.

[1] V. Cerf, S. Burleigh, A. Hooke, L. Torgerson, R. Durst, K. Scott, K. Fall, and H. Weiss, "Delay Tolerant Networking Architecture," Internet Draft: Draft-irrf-dtnrg-arch.txt, DTN Research Group, 2006.
[2] A. Vahdat and D. Becker, "Epidemic Routing for Partially-Connected Ad Hoc Networks," technical report, Duke Univ., 2002.
[3] C. Liu and J. Wu, "An Optimal Probabilistic Forwarding Protocol in Delay Tolerant Networks," Proc. ACM MobiHoc, 2009.
[4] J. Scott, R. Gass, J. Crowcroft, P. Hui, C. Diot, and A. Chaintreau, "CRAWDAD Data Set Cambridge/Haggle (v. 2006-09-15)," haggle, Sept. 2006.
[5] V. Srinivasan, M. Motani, and W.T. Ooi, "Analysis and Implications of Student Contact Patterns Derived from Campus Schedules," Proc. ACM MobiCom, 2006.
[6] X. Zhang, J.F. Kurose, B. Levine, D. Towsley, and H. Zhang, "Study of a Bus-Based Disruption Tolerant Network: Mobility Modeling and Impact on Routing," Proc. ACM MobiCom, 2007.
[7] T. Spyropoulos, K. Psounis, and C. Raghavendra, "Spray and Wait: An Efficient Routing Scheme for Intermittently Connected Mobile Networks," Proc. ACM SIGCOMM Workshop Delay-Tolerant Networking (WDTN), 2005.
[8] J. Burgess, B. Gallagher, D. Jensen, and B.N. Levine, "MaxProp: Routing for Vehicle-Based Disruption-Tolerant Networking," Proc. IEEE INFOCOM, 2006.
[9] V. Erramilli, M. Crovella, A. Chaintreau, and C. Diot, "Delegation Forwarding," Proc. ACM MobiHoc, 2008.
[10] "Optimal Stopping and Applications," http://www.math.ucla. edu/~/tom/Stopping Contents.html, 2012.
[11] A. Lindgren, A. Doria, and O. Schelen, "Probabilistic Routing in Intermittently Connected Networks," Proc. First Int'l Workshop Service Assurance with Partial and Intermittent Resources (SAPIR '04), pp. 239-254, Aug. 2004.
[12] T. Spyropoulos, K. Psounis, and C. Raghavendra, "Spray and Focus: Efficient Mobility-Assisted Routing for Heterogeneous and Correlated Mobility," Proc. IEEE Fifth Ann. Int'l Conf. Pervasive Computing and Comm. Workshops (PerCom), 2007.
[13] A. Balasubramanian, B.N. Levine, and A. Venkataramani, "DTN Routing as a Resource Allocation Problem," Proc. ACM SIGCOMM, 2007.
[14] H. Dubois-Ferriere, M. Grossglauser, and M. Vetterli, "Age Matters: Efficient Route Discovery in Mobile Ad Hoc Networks Using Encounter Ages," Proc. ACM MobiHoc, 2003.
[15] M. Grossglauser and M. Vetterli, "Locating Nodes with Ease: Last Encounter Routing in Ad Hoc Networks through Mobility Diffusion," Proc. IEEE INFOCOM, 2003.
[16] M.Y. Uddin, H. Ahmadi, T. Abdelzaher, and R. Kravets, "A Low-Energy, Multi-Copy Inter-Contact Routing Protocol for Disaster Response Networks," Proc. IEEE Sixth Ann. Comm. Soc. Conf. Sensor, Mesh, and Ad Hoc Comm. and Networks (SECON '09), 2009.
[17] E. Bulut, S.C. Geyik, and B.K. Szymanski, "Efficient Routing in Delay Tolerant Networks with Correlated Node Mobility," Proc. IEEE Seventh Int'l Conf. Mobile Ad Hoc and Sensor Systems (MASS), 2010.
[18] E. Daly and M. Haahr, "Social Network Analysis for Routing in Disconnected Delay-Tolerant MANETs," Proc. ACM MobiHoc, 2007.
[19] U. Acer, S. Kalyanaraman, and A. Abouzeid, "Weak State Routing for Large Scale Dynamic Networks," Proc. ACM MobiCom, 2007.
[20] C. Liu and J. Wu, "Routing in a Cyclic MobiSpace," Proc. ACM MobiHoc, 2008.

Index Terms:
Delay tolerant networks, optimal stopping rule, routing, simulation.
Cong Liu, Jie Wu, "On Multicopy Opportunistic Forwarding Protocols in Nondeterministic Delay Tolerant Networks," IEEE Transactions on Parallel and Distributed Systems, vol. 23, no. 6, pp. 1121-1128, June 2012, doi:10.1109/TPDS.2011.280
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