Abstract：Disruption Tolerant Network (DTN) attempts to transfer messages via intermittently connected nodes. The difficulty lies in that the routing connectivity is opportunistic, and the network topology information is lacking between nodes. Spray and Wait is an efficient routing scheme in such environment, it "sprays" a number of copies into the network, and then "waits" till one of these nodes meets the destination. Compared with epidemic routing, Spray and Wait consumes less network resources, but still suffers from severe contention under high network load. Therefore, based on the analysis of Spray and Wait routing, an ACK-mechanism was used to remove the redundant messages which lead to less network resource consumption. Meanwhile, token forwarding was adopted in order to improve the bandwidth utilization. The improved routing scheme was simulated on ONE platform and the simulation results show that it has higher average delivery rate and consumes fewer network resources though it has slight higher average delivery delay. The scheme works well in intermittently connected mobile networks without any priori connectivity knowledge.
郑恩 罗秋霞. 容断网络中基于ACK机制的喷射等待路由[J]. 计算机应用, 2012, 32(02): 367-369.
ZHENG En LUO Qiu-xia. Spray and Wait routing based on ACK-mechanism in disruption tolerant networks. Journal of Computer Applications, 2012, 32(02): 367-369.
FALL K. A delay-tolerant network architecture for challenged Internets[C]// SIGCOMM '03: Proceedings of the 2003 Conference on Applications, Technologies, Architectures, and Protocols for Computer Communications. New York: ACM, 2003：27-34.
JAIN S，FALL K，PATRA R. Routing in a delay tolerant network[C]// SIGCOMM '04: Proceedings of the 2004 Conference on Applications, Technologies, Architectures, and Protocols for Computer Communications. New York: ACM, 2004：145-158.
[5]
VAHDAT A, BECKER D. Epidemic routing for partially-connected Ad Hoc networks, CS-2000-06 [R]. Durham, NC: Duke University，2000.
[6]
SPYROPOULOS T, PSOUNIS K, RAGHAVENDRA C S. Spray and wait: an efficient routing scheme for intermittently connected mobile networks[C]// WDTN '05: Proceedings of the 2005 ACM SIGCOMM Workshop on Delay-tolerant Networking. New York：ACM，2005：252-259.
[7]
SPYROPOULOS T，PSOUNIS K，RAGHAVENDRA C S. Efficient routing in intermittently connected mobile networks: the multiple-copy case [J]. IEEE/ACM Transactions on Networking，2008，16(1)：77-90.
[8]
SPYROPOULOS T，PSOUNIS K，RAGHAVENDRA C S. Efficient routing in intermittently connected mobile networks: the single-copy case [J]. IEEE/ACM Transactions on Networking，2008，16(1)：63-76.
[9]
KERNEN A. Opportunistic network environment simulator[R]. Helsinki: Helsinki University of Technology, Department of Communications and Networking，2008.
[10]
KERNEN A, OTT J, KRKKINEN T. The ONE Simulator for DTN protocol evaluation[C]// Simutools '09: Proceedings of the 2nd International Conference on Simulation Tools and Techniques. Brussels, Belgium: ICST, 2009: 720-730.
2012, Vol. 32 
