Wireless sensor networks are widely used for its flexibility, but they also suffer from problems like limited capacity, large node number and vulnerability to security threats. In this paper, we propose a multi-path r...Wireless sensor networks are widely used for its flexibility, but they also suffer from problems like limited capacity, large node number and vulnerability to security threats. In this paper, we propose a multi-path routing protocol based on the credible cluster heads. The protocol chooses nodes with more energy remained as cluster heads at the cluster head choosing phase, and then authenticates them by the neighbor cluster heads. Using trust mechanisms it creates the credit value, and based on the credit value the multi-path cluster head routing can finally be found. The credit value is created and exchanged among the cluster heads only. Theoretical analysis combined with simulation results demonstrate that this protocol can save the resource, prolong the lifetime, and ensure the security and performance of the network.展开更多
The routing protocols play an important role for ad hoc networks performance.As some problems with DSR,SMR,and AMR protocols were analyzed,a new routing protocol suitable for UWB Ad hoc networks was proposed in this p...The routing protocols play an important role for ad hoc networks performance.As some problems with DSR,SMR,and AMR protocols were analyzed,a new routing protocol suitable for UWB Ad hoc networks was proposed in this paper.The new routing protocol utilize an act of orientation of UWB and tries to get sufficient route information and decrease the network load caused by route discovery at the same time.Simulation results show that the routing load of the new protocol is lower and throughput is higher than that of DSR.While the node’s mobility increases,these advantages become more obvious.展开更多
Many ＂rich - connected＂ topologies with multiple parallel paths between smwers have been proposed for data center networks recently to provide high bisection bandwidth, but it re mains challenging to fully utilize t...Many ＂rich - connected＂ topologies with multiple parallel paths between smwers have been proposed for data center networks recently to provide high bisection bandwidth, but it re mains challenging to fully utilize the high network capacity by appropriate multi- path routing algorithms. As flow-level path splitting may lead to trafl＇ic imbalance between paths due to flow- size difference, packet-level path splitting attracts more attention lately, which spreads packets from flows into multiple available paths and significantly improves link utilizations. However, it may cause packet reordering, confusing the TCP congestion control algorithm and lowering the throughput of flows. In this paper, we design a novel packetlevel multi-path routing scheme called SOPA, which leverag- es OpenFlow to perform packet-level path splitting in a round- robin fashion, and hence significantly mitigates the packet reordering problem and improves the network throughput. Moreover, SOPA leverages the topological feature of data center networks to encode a very small number of switches along the path into the packet header, resulting in very light overhead. Compared with random packet spraying （RPS）, Hedera and equal-cost multi-path routing （ECMP）, our simulations demonstrate that SOPA achieves 29.87%, 50.41% and 77.74% higher network throughput respectively under permutation workload, and reduces average data transfer completion time by 53.65%, 343.31% and 348.25% respectively under production workload.展开更多
In wavelength division multiplexing (WDM) networks without wavelengthconversion functionality, we convert the dynamic routing and wavelength assignment problem formulti-lightpath demands to the edge-disjoint paths pro...In wavelength division multiplexing (WDM) networks without wavelengthconversion functionality, we convert the dynamic routing and wavelength assignment problem formulti-lightpath demands to the edge-disjoint paths problem, and propose a new algorithm. Thecomputer simulations show that the proposed algorithm has better blocking probability performancethan a sequential algorithm, which first separates a multi-lightpath demand into mutilplesingle-lightpath demands, then uses the fixed-alternate routing-first fit wavelength assignment(AR-FF) algorithm for each single-lightpath demand.展开更多
Owing to the long propagation delay and high error rate of acoustic channels, it is very challenging to provide reliable data transfer for underwater sensor networks. Moreover, network coding is proved to be an effect...Owing to the long propagation delay and high error rate of acoustic channels, it is very challenging to provide reliable data transfer for underwater sensor networks. Moreover, network coding is proved to be an effective coding technique for throughput and robustness of networks. In this paper, we propose a Reliable Braided Multipath Routing with Network Coding for underwater sensor networks （RBMR-NC）. Disjoint multi-path algorithm is used to build independent actual paths, as called main paths. Some braided paths on each main path are built according to the braided multi-path algorithm, which are called logic paths. When a data packet is transmitted by these nodes, the nodes can employ network coding to encode packets coming from the same group in order to further reduce relativity among these packets, and enhance the probability of successful decoding at the sink node. Braided multi-path can make the main paths to be multiplexed to reduce the probability of long paths. This paper mainly employs successful delivery rate to evaluate RBMR-NC model with theoretical analysis and simulation methods. The results indicate that the proposed RBMR-NC protocol is valuable to enhance network reliability and to reduce system redundancy.展开更多
The support for multiple video streams in an ad-hoc wireless network requires appropriate routing and rate allocation measures ascertaining the set of links for transmitting each stream and the encoding rate of the vi...The support for multiple video streams in an ad-hoc wireless network requires appropriate routing and rate allocation measures ascertaining the set of links for transmitting each stream and the encoding rate of the video to be delivered over the chosen links. The routing and rate allocation procedures impact the sustained quality of each video stream measured as the mean squared error (MSE) distortion at the receiver, and the overall network congestion in terms of queuing delay per link. We study the trade-off between these two competing objectives in a convex optimization formulation, and discuss both centralized and dis- tributed solutions for joint routing and rate allocation for multiple streams. For each stream, the optimal allocated rate strikes a balance between the selfish motive of minimizing video distortion and the global good of minimizing network congestions, while the routes are chosen over the least-congested links in the network. In addition to detailed analysis, network simulation results using ns-2 are presented for studying the optimal choice of parameters and to confirm the effectiveness of the proposed measures.展开更多
It is a challenging problem to provide quality-of-service （QoS） guarantees in next generation high-speed network, and the QoS routing is one of the key issues of the problem. For the problem of multi-constrained QoS...It is a challenging problem to provide quality-of-service （QoS） guarantees in next generation high-speed network, and the QoS routing is one of the key issues of the problem. For the problem of multi-constrained QoS routing in high-speed network, especially under the inaccurate link state information, the success ratio of the different constraint combination is analyzed statistically, and a constraint analysis method based on the computer simulation is proposed. Furthermore, the approximately equal loose-tight order relation between each two constraints is constructed, and then an algorithm based on the experimental analysis is presented. Finally, the simulation result demonstrates that the algorithm has the higher success ratio, and the theoretical analysis proves its correctness and universality.展开更多
A quality of service （QoS） or constraint-based routing selection needs to find a path subject to multiple constraints through a network. The problem of finding such a path is known as the multi-constrained path （MC...A quality of service （QoS） or constraint-based routing selection needs to find a path subject to multiple constraints through a network. The problem of finding such a path is known as the multi-constrained path （MCP） problem, and has been proven to be NP-complete that cannot be exactly solved in a polynomial time. The NPC problem is converted into a multiobjective optimization problem with constraints to be solved with a genetic algorithm. Based on the Pareto optimum, a constrained routing computation method is proposed to generate a set of nondominated optimal routes with the genetic algorithm mechanism. The convergence and time complexity of the novel algorithm is analyzed. Experimental results show that multiobjective evolution is highly responsive and competent for the Pareto optimum-based route selection. When this method is applied to a MPLS and metropolitan-area network, it will be capable of optimizing the transmission performance.展开更多
Quality of service （QoS） routing algorithms have been hardly discussed in the scientific community, most previous work on QoS routing concentrates on the performance of the single route. Cognitive packet network （...Quality of service （QoS） routing algorithms have been hardly discussed in the scientific community, most previous work on QoS routing concentrates on the performance of the single route. Cognitive packet network （CPN） has been designed for providing QoS routing. In this paper, to balance the loads among networks, we present a multi-path routing algorithm based on load-balance （MPRLB）, which is carried out in two steps. The algorithm with low computational complexity is firstly applied to establish multi path routing for each source and destination node pairs （SD-pair） nodes in the network. Then, we propose the hopfield neural network algorithm, which is applied to improve the efficiency of the flow deviation method for fast flow allocation among the links of the network based on load balance. Extensive simulation results demonstrate that the proposed scheme significantly improves the performance compared with the existing scheme that ignores load balancing.展开更多
As an important secure routing mechanism, multi-path routing is one of the major ways to improve network efficiency and to guarantee the network security, which ensures the reliability of data transmission by using ba...As an important secure routing mechanism, multi-path routing is one of the major ways to improve network efficiency and to guarantee the network security, which ensures the reliability of data transmission by using backup paths when the primary one is unavailable due to local node or link failures. Most current studies on multi-path routing mechanism are based on experiments or simulations. The resulta are usually specific application scenarios oriented heuristic algorithms, lacking universal significance. In this paper, a theoretic analysis is performed on the relationship between the multi-path routing policy, the network efficiency and its survivability. Starting with point-to-point communication network, an impactoriented analysis is made on the network interference under multi-path routing mechanism. Based on the analysis, the upper-limit of network performance under interference impact is also discussed.展开更多
为了减少建立路由所产生的延时,AODV路由协议允许拥有积极路由的中间节点响应路由请求,而不考虑该节点当时的负荷,这样虽然快速地建立了路由,但并不一定能有效地传输数据。针对这一问题,在AODV的基础上对一种多路径路由方法MP-AOMDV进...为了减少建立路由所产生的延时,AODV路由协议允许拥有积极路由的中间节点响应路由请求,而不考虑该节点当时的负荷,这样虽然快速地建立了路由,但并不一定能有效地传输数据。针对这一问题,在AODV的基础上对一种多路径路由方法MP-AOMDV进行了优化。这种优化的协议我们称为EMP-AOMDV(Enhanced Ad hoc On-demand Multi-path Vector Routing Protocol)。结果表明改进的协议和原协议相比,降低了端到端的延时和丢包率,提高了传输效率。展开更多
OSPF（Open Shortest Path First Protocol）协议是目前Internet上广泛使用的自治系统内部交换路由信息的动态路由协议。文章介绍了在清华大学研制的国产高性能路由器中分布式路由协议OSPF－2的具体实现。为了实现这一复杂的动态协议，...OSPF（Open Shortest Path First Protocol）协议是目前Internet上广泛使用的自治系统内部交换路由信息的动态路由协议。文章介绍了在清华大学研制的国产高性能路由器中分布式路由协议OSPF－2的具体实现。为了实现这一复杂的动态协议，文章提出了基于事件驱动的虚拟多任务机制的设计和实现方法。这种机制能够有效支持复杂系统的分解，在实时性要求不高的前提下提供一种简便有效的并行机制，方便基于状态机的软件实现，提高了软件的可移植性。该方法对于其它的Internet高层协议的设计和实现也有一定的参考价值。展开更多
文摘Wireless sensor networks are widely used for its flexibility, but they also suffer from problems like limited capacity, large node number and vulnerability to security threats. In this paper, we propose a multi-path routing protocol based on the credible cluster heads. The protocol chooses nodes with more energy remained as cluster heads at the cluster head choosing phase, and then authenticates them by the neighbor cluster heads. Using trust mechanisms it creates the credit value, and based on the credit value the multi-path cluster head routing can finally be found. The credit value is created and exchanged among the cluster heads only. Theoretical analysis combined with simulation results demonstrate that this protocol can save the resource, prolong the lifetime, and ensure the security and performance of the network.
基金National Nature Science Foundation of China (No. 60496311)Nature Science Foundation of Jiangsu Province (No. BK2004067&BK2005409)Foundation of Huawei Technology (No. YJCB2004018NP).
文摘The routing protocols play an important role for ad hoc networks performance.As some problems with DSR,SMR,and AMR protocols were analyzed,a new routing protocol suitable for UWB Ad hoc networks was proposed in this paper.The new routing protocol utilize an act of orientation of UWB and tries to get sufficient route information and decrease the network load caused by route discovery at the same time.Simulation results show that the routing load of the new protocol is lower and throughput is higher than that of DSR.While the node’s mobility increases,these advantages become more obvious.
基金supported by the National Basic Research Program of China(973 program)under Grant No.2014CB347800 and No.2012CB315803the National High-Tech R&D Program of China(863 program)under Grant No.2013AA013303+1 种基金the Natural Science Foundation of China under Grant No.61170291,No.61133006,and No.61161140454ZTE IndustryAcademia-Research Cooperation Funds
文摘Many ＂rich - connected＂ topologies with multiple parallel paths between smwers have been proposed for data center networks recently to provide high bisection bandwidth, but it re mains challenging to fully utilize the high network capacity by appropriate multi- path routing algorithms. As flow-level path splitting may lead to trafl＇ic imbalance between paths due to flow- size difference, packet-level path splitting attracts more attention lately, which spreads packets from flows into multiple available paths and significantly improves link utilizations. However, it may cause packet reordering, confusing the TCP congestion control algorithm and lowering the throughput of flows. In this paper, we design a novel packetlevel multi-path routing scheme called SOPA, which leverag- es OpenFlow to perform packet-level path splitting in a round- robin fashion, and hence significantly mitigates the packet reordering problem and improves the network throughput. Moreover, SOPA leverages the topological feature of data center networks to encode a very small number of switches along the path into the packet header, resulting in very light overhead. Compared with random packet spraying （RPS）, Hedera and equal-cost multi-path routing （ECMP）, our simulations demonstrate that SOPA achieves 29.87%, 50.41% and 77.74% higher network throughput respectively under permutation workload, and reduces average data transfer completion time by 53.65%, 343.31% and 348.25% respectively under production workload.
基金Supported by the National High Technology Development 863 Program of China(2001AA122023)
文摘In wavelength division multiplexing (WDM) networks without wavelengthconversion functionality, we convert the dynamic routing and wavelength assignment problem formulti-lightpath demands to the edge-disjoint paths problem, and propose a new algorithm. Thecomputer simulations show that the proposed algorithm has better blocking probability performancethan a sequential algorithm, which first separates a multi-lightpath demand into mutilplesingle-lightpath demands, then uses the fixed-alternate routing-first fit wavelength assignment(AR-FF) algorithm for each single-lightpath demand.
基金supported by the National Natural Science Foundation of China (Grant Nos.60472060 and 60473039)the National High Technology Research and Development Programof China (863 Program,Grant No.2006AA01Z119)the Innovation Fund of Chinese Academy of Space Technology (Grant No.CAST20090801)
文摘Owing to the long propagation delay and high error rate of acoustic channels, it is very challenging to provide reliable data transfer for underwater sensor networks. Moreover, network coding is proved to be an effective coding technique for throughput and robustness of networks. In this paper, we propose a Reliable Braided Multipath Routing with Network Coding for underwater sensor networks （RBMR-NC）. Disjoint multi-path algorithm is used to build independent actual paths, as called main paths. Some braided paths on each main path are built according to the braided multi-path algorithm, which are called logic paths. When a data packet is transmitted by these nodes, the nodes can employ network coding to encode packets coming from the same group in order to further reduce relativity among these packets, and enhance the probability of successful decoding at the sink node. Braided multi-path can make the main paths to be multiplexed to reduce the probability of long paths. This paper mainly employs successful delivery rate to evaluate RBMR-NC model with theoretical analysis and simulation methods. The results indicate that the proposed RBMR-NC protocol is valuable to enhance network reliability and to reduce system redundancy.
基金Project (No. CCR-0325639) partially supported by the National Science Foundation, USA
文摘The support for multiple video streams in an ad-hoc wireless network requires appropriate routing and rate allocation measures ascertaining the set of links for transmitting each stream and the encoding rate of the video to be delivered over the chosen links. The routing and rate allocation procedures impact the sustained quality of each video stream measured as the mean squared error (MSE) distortion at the receiver, and the overall network congestion in terms of queuing delay per link. We study the trade-off between these two competing objectives in a convex optimization formulation, and discuss both centralized and dis- tributed solutions for joint routing and rate allocation for multiple streams. For each stream, the optimal allocated rate strikes a balance between the selfish motive of minimizing video distortion and the global good of minimizing network congestions, while the routes are chosen over the least-congested links in the network. In addition to detailed analysis, network simulation results using ns-2 are presented for studying the optimal choice of parameters and to confirm the effectiveness of the proposed measures.
文摘It is a challenging problem to provide quality-of-service （QoS） guarantees in next generation high-speed network, and the QoS routing is one of the key issues of the problem. For the problem of multi-constrained QoS routing in high-speed network, especially under the inaccurate link state information, the success ratio of the different constraint combination is analyzed statistically, and a constraint analysis method based on the computer simulation is proposed. Furthermore, the approximately equal loose-tight order relation between each two constraints is constructed, and then an algorithm based on the experimental analysis is presented. Finally, the simulation result demonstrates that the algorithm has the higher success ratio, and the theoretical analysis proves its correctness and universality.
基金the Natural Science Foundation of Anhui Province of China (050420212)the Excellent Youth Science and Technology Foundation of Anhui Province of China (04042069).
文摘A quality of service （QoS） or constraint-based routing selection needs to find a path subject to multiple constraints through a network. The problem of finding such a path is known as the multi-constrained path （MCP） problem, and has been proven to be NP-complete that cannot be exactly solved in a polynomial time. The NPC problem is converted into a multiobjective optimization problem with constraints to be solved with a genetic algorithm. Based on the Pareto optimum, a constrained routing computation method is proposed to generate a set of nondominated optimal routes with the genetic algorithm mechanism. The convergence and time complexity of the novel algorithm is analyzed. Experimental results show that multiobjective evolution is highly responsive and competent for the Pareto optimum-based route selection. When this method is applied to a MPLS and metropolitan-area network, it will be capable of optimizing the transmission performance.
基金supported by the Ministry of Industry and Information Technology of China (2011ZX03001-007-03)the Nature Science Foundation of Beijing (4102044)the National Science Foundation for Young Scientists of China (61001115)
文摘Quality of service （QoS） routing algorithms have been hardly discussed in the scientific community, most previous work on QoS routing concentrates on the performance of the single route. Cognitive packet network （CPN） has been designed for providing QoS routing. In this paper, to balance the loads among networks, we present a multi-path routing algorithm based on load-balance （MPRLB）, which is carried out in two steps. The algorithm with low computational complexity is firstly applied to establish multi path routing for each source and destination node pairs （SD-pair） nodes in the network. Then, we propose the hopfield neural network algorithm, which is applied to improve the efficiency of the flow deviation method for fast flow allocation among the links of the network based on load balance. Extensive simulation results demonstrate that the proposed scheme significantly improves the performance compared with the existing scheme that ignores load balancing.
基金the National Basic Research Development Program of China (Grant No. 2003CB314805)the National Nature Science Foundation of China (Grant No. 60603022)
文摘As an important secure routing mechanism, multi-path routing is one of the major ways to improve network efficiency and to guarantee the network security, which ensures the reliability of data transmission by using backup paths when the primary one is unavailable due to local node or link failures. Most current studies on multi-path routing mechanism are based on experiments or simulations. The resulta are usually specific application scenarios oriented heuristic algorithms, lacking universal significance. In this paper, a theoretic analysis is performed on the relationship between the multi-path routing policy, the network efficiency and its survivability. Starting with point-to-point communication network, an impactoriented analysis is made on the network interference under multi-path routing mechanism. Based on the analysis, the upper-limit of network performance under interference impact is also discussed.
文摘为了减少建立路由所产生的延时,AODV路由协议允许拥有积极路由的中间节点响应路由请求,而不考虑该节点当时的负荷,这样虽然快速地建立了路由,但并不一定能有效地传输数据。针对这一问题,在AODV的基础上对一种多路径路由方法MP-AOMDV进行了优化。这种优化的协议我们称为EMP-AOMDV(Enhanced Ad hoc On-demand Multi-path Vector Routing Protocol)。结果表明改进的协议和原协议相比,降低了端到端的延时和丢包率,提高了传输效率。
文摘OSPF（Open Shortest Path First Protocol）协议是目前Internet上广泛使用的自治系统内部交换路由信息的动态路由协议。文章介绍了在清华大学研制的国产高性能路由器中分布式路由协议OSPF－2的具体实现。为了实现这一复杂的动态协议，文章提出了基于事件驱动的虚拟多任务机制的设计和实现方法。这种机制能够有效支持复杂系统的分解，在实时性要求不高的前提下提供一种简便有效的并行机制，方便基于状态机的软件实现，提高了软件的可移植性。该方法对于其它的Internet高层协议的设计和实现也有一定的参考价值。
