在MANET中,通信节点的移动会造成端到端通信路由的时常中断.传统TCP协议只有拥塞控制机制,对由于节点移动造成的数据包传输丢失和超时也作为拥塞处理,使得端到端传输性能低下.为解决这一问题,采用跨层设计思想,将传输控制与链路稳定性...在MANET中,通信节点的移动会造成端到端通信路由的时常中断.传统TCP协议只有拥塞控制机制,对由于节点移动造成的数据包传输丢失和超时也作为拥塞处理,使得端到端传输性能低下.为解决这一问题,采用跨层设计思想,将传输控制与链路稳定性路由结合,提出了一种基于链路生存时间概率的传输控制协议(transmissioncontrol protocol based on probability of link residual lifetime,简称TCP-PLRT).该协议通过在路由稳定时跨层收集路由层链路生存时间概率信息来实现对端到端连接稳定性的认知,并针对路由不稳定、路由中断、路由恢复,分别制定了路由切换、数据存储转发、ACK再确认三大机制.这使得TCP-PLRT协议具有对由移动造成的路由中断进行提前预判和有效处理的能力.仿真结果表明,TCP-PLRT协议能够极大地减小由节点移动带来的端到端传输性能的下降,减少分组重传,提高端到端的吞吐量.展开更多
There were many contradictory evaluation criteria to select next-hop in the delay-disruption tolerance networks(DTN).To solve this problem,an attribute hierarchical model was proposed,in which the predefined criteria ...There were many contradictory evaluation criteria to select next-hop in the delay-disruption tolerance networks(DTN).To solve this problem,an attribute hierarchical model was proposed,in which the predefined criteria were summarized as static identity attributes,forwarding desire attributes and delivery capability attributes(IDC).Based on this model,a novel multi-attributes congestion aware routing(MACAR) scheme with uncertain information for next-hop selection was presented,by adopting an decision theory to aggregate attributes with belief structure and computing partial ordering relations.The simulation results show that MACAR presents higher successful delivery rate,lower average delay and effectively alleviate congestion.展开更多
Delay/disruption tolerant networking （DTN） is an approach to networking where intermittent connectivity exists： it is often afforded by a store and forward technique. Depending on the capability of intermediary nod...Delay/disruption tolerant networking （DTN） is an approach to networking where intermittent connectivity exists： it is often afforded by a store and forward technique. Depending on the capability of intermediary nodes to carry and forward messages, messages can be eventually delivered to their destination by mobile nodes with an appropriate routing protocol. To have achieved a successful delivery, most DTN routing protocols use message duplication methods. Although messages are rapidly transferred to the destination, the redundancy in the number of message copies increases rapidly. This paper presents a new routing scheme based on a stochastic process for epidemic routing. Message redundancy is efficiently reduced and the number of message copies is controlled reasonably. During the contact process of nodes in the network, the number of message copies changes, and according to the variability in the number of copies, we construct a special Markov chain, birth and death process, on the number of message copies then calculate and obtain a stationary distribution of the birth and death process. Comparing the theoretical model with the simulation we have performed we see similar results. Our method improves on time-to-live （TTL） and antipacket methods, in both redundancy and delivery success efficiency.展开更多
文摘在MANET中,通信节点的移动会造成端到端通信路由的时常中断.传统TCP协议只有拥塞控制机制,对由于节点移动造成的数据包传输丢失和超时也作为拥塞处理,使得端到端传输性能低下.为解决这一问题,采用跨层设计思想,将传输控制与链路稳定性路由结合,提出了一种基于链路生存时间概率的传输控制协议(transmissioncontrol protocol based on probability of link residual lifetime,简称TCP-PLRT).该协议通过在路由稳定时跨层收集路由层链路生存时间概率信息来实现对端到端连接稳定性的认知,并针对路由不稳定、路由中断、路由恢复,分别制定了路由切换、数据存储转发、ACK再确认三大机制.这使得TCP-PLRT协议具有对由移动造成的路由中断进行提前预判和有效处理的能力.仿真结果表明,TCP-PLRT协议能够极大地减小由节点移动带来的端到端传输性能的下降,减少分组重传,提高端到端的吞吐量.
基金Project(60973127) supported by the National Natural Science Foundation of ChinaProject(09JJ3123) supported by the Natural Science Foundation of Hunan Province,China
文摘There were many contradictory evaluation criteria to select next-hop in the delay-disruption tolerance networks(DTN).To solve this problem,an attribute hierarchical model was proposed,in which the predefined criteria were summarized as static identity attributes,forwarding desire attributes and delivery capability attributes(IDC).Based on this model,a novel multi-attributes congestion aware routing(MACAR) scheme with uncertain information for next-hop selection was presented,by adopting an decision theory to aggregate attributes with belief structure and computing partial ordering relations.The simulation results show that MACAR presents higher successful delivery rate,lower average delay and effectively alleviate congestion.
文摘Delay/disruption tolerant networking （DTN） is an approach to networking where intermittent connectivity exists： it is often afforded by a store and forward technique. Depending on the capability of intermediary nodes to carry and forward messages, messages can be eventually delivered to their destination by mobile nodes with an appropriate routing protocol. To have achieved a successful delivery, most DTN routing protocols use message duplication methods. Although messages are rapidly transferred to the destination, the redundancy in the number of message copies increases rapidly. This paper presents a new routing scheme based on a stochastic process for epidemic routing. Message redundancy is efficiently reduced and the number of message copies is controlled reasonably. During the contact process of nodes in the network, the number of message copies changes, and according to the variability in the number of copies, we construct a special Markov chain, birth and death process, on the number of message copies then calculate and obtain a stationary distribution of the birth and death process. Comparing the theoretical model with the simulation we have performed we see similar results. Our method improves on time-to-live （TTL） and antipacket methods, in both redundancy and delivery success efficiency.
