在容迟网络环境下,文中提出一种基于动态半马尔可夫路径搜索模型的分簇路由方法 CRSMP(Clustering Routing method based on Semi-Markov process and Path-finding strategy),该方法既考虑了节点拥有的社会属性所导致的分簇问题,又考...在容迟网络环境下,文中提出一种基于动态半马尔可夫路径搜索模型的分簇路由方法 CRSMP(Clustering Routing method based on Semi-Markov process and Path-finding strategy),该方法既考虑了节点拥有的社会属性所导致的分簇问题,又考虑到节点间未来一段时间内的最大相遇概率以及对应的相遇时间,结合分簇结果和相遇情况生成动态路由表,完成一种单副本的路由方法.该方法首先依据节点间路径的相似程度进行分簇,然后运用半马尔可夫模型预测节点间未来某一时刻的相遇概率,依据源节点和目的节点所在的分簇确定可以应用到路由中的节点集合,最后根据路径搜索策略找到最优路径,生成与当前时刻有关的动态路由表.仿真结果表明CRSMP在缓存较小的情况下投递成功率远高于DirectDeliveryRouter、FirstContactRouter和SimBetRouter三种单副本路由方式以及Spray and Wait、Epidemic和Prophet三种多副本路由协议.在10M缓存下的CRSMP有着与500M缓存下的Epidemic相近的路由性能.进一步在真实数据集上进行测试,测试结果表明CRSMP算法依然有着较好的路由性能.展开更多
提出了一种DTN多源多宿网络的数据编码分发机制(Data Dissemination Mechanism with Network Coding Based on Ant Colony Algorithm,DDM-NC).在发布/订阅机制的基础上,通过对主题数据的编码运算和传输,充分利用网络容量进行数据多播,...提出了一种DTN多源多宿网络的数据编码分发机制(Data Dissemination Mechanism with Network Coding Based on Ant Colony Algorithm,DDM-NC).在发布/订阅机制的基础上,通过对主题数据的编码运算和传输,充分利用网络容量进行数据多播,使得数据传输具有更好的安全性和传输效率;同时,针对编码包洪泛传输过程中信息冗余大,无效投递较多等问题,设计了基于蚁群算法的编码包路由策略,引导编码包向信宿聚集,降低编码投递过程中的数据冗余,减少投递延迟.仿真实验表明,相比传统的DTN传染病路由策略和随机网络编码传输方法,DDM-NC方法有更好的数据投递性能.展开更多
Delay Tolerant Network (DTN) addresses challenges of providing end-to-end service where end-to-end data forwarding paths may not exist. Security and privacy are crucial to the wide deployments of DTN. Without security...Delay Tolerant Network (DTN) addresses challenges of providing end-to-end service where end-to-end data forwarding paths may not exist. Security and privacy are crucial to the wide deployments of DTN. Without security and privacy guarantees, people are reluctant to accept such a new network paradigm. To address the security and privacy issues in DTNs, we in this paper have discussed the various open issues and challenges which need to be addressed to evolve the secure DTNs.展开更多
Routing is one of the challenging tasks in Delay Tolerant Networks （DTNs）, due to the lack of global knowledge and sporadic contacts between nodes. Most existing studies take a greedy scheme in data forwarding proce...Routing is one of the challenging tasks in Delay Tolerant Networks （DTNs）, due to the lack of global knowledge and sporadic contacts between nodes. Most existing studies take a greedy scheme in data forwarding process, i.e., only nodes with higher utility values than current carriers can be selected as relays. They lack an in-depth investigation on the main features of the optimal paths in Epidemic. These features are vital to any forwarding scheme that tends to make a trade-off between packet delivery delay and cost. This is mainly because Epidemic provides an upper bound on cost and a lower bound on delivery delay. Therefore, a deep understanding of these features is useful to make informed forwarding decisions. In this paper, we try to explore these features by observing the roles of different social relationships in the optimal paths through a set of real datasets. These datasets provide evidence that strangers have two sides in data forwarding process, and that the importance of strangers shows a decreasing trend along the forwarding paths. Using this heuristic knowledge, we propose STRON, a distributed and lightweight forwarding scheme. The distributed feature makes it very suitable for opportunistic scenarios and the low communication and computation features make it easy to be integrated with state-of-the-art work. The trace-driven simulations obviously confirm its effectiveness, especially in terms of packet delivery delay and cost.展开更多
针对容迟网络中节点存储空间有限从而出现大量丢包情况的问题,本文提出了一种适用于节点环境状态的拥塞控制管理策略(congestion control management strategy suitable for the state of the node environment,NEMS):该策略由节点间位...针对容迟网络中节点存储空间有限从而出现大量丢包情况的问题,本文提出了一种适用于节点环境状态的拥塞控制管理策略(congestion control management strategy suitable for the state of the node environment,NEMS):该策略由节点间位置差异相关的控制保留策略和节点自差异相关的丢包策略构成.首先根据节点剩余缓存空间的大小判断节点是处于忙碌状态(BS)还是崩溃状态(CS),当节点处于BS状态时,节点间位置差异相关的控制保留策略结合门限度和连接活跃值的概念分析是否留存新消息.节点自差异相关的丢包策略利用熵权法动态计算各个节点中不同消息属性权重,得到消息丢弃优先级.当拥塞发生,优先删除丢弃优先级大的消息.同时,引入ACK反馈机制,消除网络中已成功投递的冗余消息.仿真结果表明,与无缓存管理的路由策略相比,加入NEMS后使得消息成功投递率增加了约100.93%~200.67%,网络负载降低了约76.05%~81.42%.展开更多
文摘在容迟网络环境下,文中提出一种基于动态半马尔可夫路径搜索模型的分簇路由方法 CRSMP(Clustering Routing method based on Semi-Markov process and Path-finding strategy),该方法既考虑了节点拥有的社会属性所导致的分簇问题,又考虑到节点间未来一段时间内的最大相遇概率以及对应的相遇时间,结合分簇结果和相遇情况生成动态路由表,完成一种单副本的路由方法.该方法首先依据节点间路径的相似程度进行分簇,然后运用半马尔可夫模型预测节点间未来某一时刻的相遇概率,依据源节点和目的节点所在的分簇确定可以应用到路由中的节点集合,最后根据路径搜索策略找到最优路径,生成与当前时刻有关的动态路由表.仿真结果表明CRSMP在缓存较小的情况下投递成功率远高于DirectDeliveryRouter、FirstContactRouter和SimBetRouter三种单副本路由方式以及Spray and Wait、Epidemic和Prophet三种多副本路由协议.在10M缓存下的CRSMP有着与500M缓存下的Epidemic相近的路由性能.进一步在真实数据集上进行测试,测试结果表明CRSMP算法依然有着较好的路由性能.
文摘提出了一种DTN多源多宿网络的数据编码分发机制(Data Dissemination Mechanism with Network Coding Based on Ant Colony Algorithm,DDM-NC).在发布/订阅机制的基础上,通过对主题数据的编码运算和传输,充分利用网络容量进行数据多播,使得数据传输具有更好的安全性和传输效率;同时,针对编码包洪泛传输过程中信息冗余大,无效投递较多等问题,设计了基于蚁群算法的编码包路由策略,引导编码包向信宿聚集,降低编码投递过程中的数据冗余,减少投递延迟.仿真实验表明,相比传统的DTN传染病路由策略和随机网络编码传输方法,DDM-NC方法有更好的数据投递性能.
文摘Delay Tolerant Network (DTN) addresses challenges of providing end-to-end service where end-to-end data forwarding paths may not exist. Security and privacy are crucial to the wide deployments of DTN. Without security and privacy guarantees, people are reluctant to accept such a new network paradigm. To address the security and privacy issues in DTNs, we in this paper have discussed the various open issues and challenges which need to be addressed to evolve the secure DTNs.
基金supported by the National Basic Research 973 Program of China under Grant No. 2011CB302701the National Science Fund for Distinguished Young Scholars of China under Grant No. 60925010+3 种基金the National Natural Science Foundation of Chinaunder Grant Nos. 61133015, 61003280, and 61272517the Funds for Creative Research Groups of China under Grant No. 61121001the Program for Changjiang Scholars and Innovative Research Team in University of China under Grant No. IRT1049the Research Fund for the Doctoral Program of Higher Education of China under Grant No. 20120005130002
文摘Routing is one of the challenging tasks in Delay Tolerant Networks （DTNs）, due to the lack of global knowledge and sporadic contacts between nodes. Most existing studies take a greedy scheme in data forwarding process, i.e., only nodes with higher utility values than current carriers can be selected as relays. They lack an in-depth investigation on the main features of the optimal paths in Epidemic. These features are vital to any forwarding scheme that tends to make a trade-off between packet delivery delay and cost. This is mainly because Epidemic provides an upper bound on cost and a lower bound on delivery delay. Therefore, a deep understanding of these features is useful to make informed forwarding decisions. In this paper, we try to explore these features by observing the roles of different social relationships in the optimal paths through a set of real datasets. These datasets provide evidence that strangers have two sides in data forwarding process, and that the importance of strangers shows a decreasing trend along the forwarding paths. Using this heuristic knowledge, we propose STRON, a distributed and lightweight forwarding scheme. The distributed feature makes it very suitable for opportunistic scenarios and the low communication and computation features make it easy to be integrated with state-of-the-art work. The trace-driven simulations obviously confirm its effectiveness, especially in terms of packet delivery delay and cost.
文摘针对容迟网络中节点存储空间有限从而出现大量丢包情况的问题,本文提出了一种适用于节点环境状态的拥塞控制管理策略(congestion control management strategy suitable for the state of the node environment,NEMS):该策略由节点间位置差异相关的控制保留策略和节点自差异相关的丢包策略构成.首先根据节点剩余缓存空间的大小判断节点是处于忙碌状态(BS)还是崩溃状态(CS),当节点处于BS状态时,节点间位置差异相关的控制保留策略结合门限度和连接活跃值的概念分析是否留存新消息.节点自差异相关的丢包策略利用熵权法动态计算各个节点中不同消息属性权重,得到消息丢弃优先级.当拥塞发生,优先删除丢弃优先级大的消息.同时,引入ACK反馈机制,消除网络中已成功投递的冗余消息.仿真结果表明,与无缓存管理的路由策略相比,加入NEMS后使得消息成功投递率增加了约100.93%~200.67%,网络负载降低了约76.05%~81.42%.
