GMPLS(generalized multi protocol label switching)网络中的多约束QoS路由问题是要在诸如带宽、代价和延迟的约束条件下找到一条优化的路径.这个问题通常被认为是一个NP-完全问题.在研究共享风险链路组具有的启发信息的基础上,提出了...GMPLS(generalized multi protocol label switching)网络中的多约束QoS路由问题是要在诸如带宽、代价和延迟的约束条件下找到一条优化的路径.这个问题通常被认为是一个NP-完全问题.在研究共享风险链路组具有的启发信息的基础上,提出了一种具有共享风险链路启发信息的多约束预计算算法.该算法包含预计算和搜索两个部分.预计算主要是能创建和更新每个节点上的路由表.而后,搜索部分则可以在层次化的结构中选择满足约束条件的优化的路径.大量仿真数据表明,相应的方法能够取得满意的结果,可以有效地解决GMPLS网络中多约束的QoS路由问题.展开更多
This paper investigates the performability of hierarchical Wireless Networked Control Systems (WNCS). The WNCS studied can operate in two modes: passive supervisor and active supervisor. It is first shown that the Mar...This paper investigates the performability of hierarchical Wireless Networked Control Systems (WNCS). The WNCS studied can operate in two modes: passive supervisor and active supervisor. It is first shown that the Markov models for both modes are identical. Performability models are then developed and a case study shows how to use these models to help make design decisions. More specifically, it is observed that the performability of a passive supervisor system increases in time while that of an active supervisor system decreases in time.展开更多
We present an effective routing solution for the backbone of hierarchical MANETs. </span></span><span><span><span style="font-family:""><span style="font-family:Ver...We present an effective routing solution for the backbone of hierarchical MANETs. </span></span><span><span><span style="font-family:""><span style="font-family:Verdana;">Our solution leverages the storage and retrieval mechanisms of a Distributed Hash Table (DHT) common to many (structured) P2P overlays. Th</span><span style="font-family:Verdana;">e DHT provides routing information in a decentralized fash</span><span style="font-family:Verdana;">ion, while supporting different forms of node and network mobility. We split a flat network into clusters, each having a gateway who participates in a DHT overlay. These g</span><span style="font-family:Verdana;">ateways interconnect the clusters in a backbone network. Two routing </span><span style="font-family:Verdana;">approaches for the backbone are explore</span><span style="font-family:Verdana;">d: floodi</span><span style="font-family:Verdana;">ng and a new solution exploit</span><span style="font-family:Verdana;">ing the storage and retrieval capabilities of a P2P overlay based on a DHT.</span><span style="font-family:Verdana;"> We </span><span style="font-family:Verdana;">implement both approaches in a net</span><span style="font-family:Verdana;">work simulator and thoroughly evaluate th</span><span style="font-family:Verdana;">e performance of the proposed scheme using a range of stati</span><span style="font-family:Verdana;">c and mobile scenarios. We also compare our solution against flooding. The simulation results show that our solution, even in the presence of mobility, achieved well abo</span><span style="font-family:Verdana;">ve 90% success rates and maintained very low and constant round tr</span><span style="font-family:Verdana;">ip times, unlike the flooding approach. In fact, the performance of the proposed </span><span style="font-family:Verdana;">inter-cluster routing solution, in many cases, is comparable to the perfo</span><span style="font-family:Verdana;">rma</span><span style="font-family:Verdana;">nce of the intra-cluster routing case. The ad展开更多
In hierarchical networks, nodes are separated to play different roles such as CHs and cluster members. Each CH collects data from the cluster members within its cluster, aggregates the data and then transmits the data...In hierarchical networks, nodes are separated to play different roles such as CHs and cluster members. Each CH collects data from the cluster members within its cluster, aggregates the data and then transmits the data to the sink. Each algorithm that is used for packet routing in quality of service (QoS) based applications should be able to establish a tradeoffs between end to end delay parameter and energy consumption. Therefore, enabling QoS applications in sensor networks requires energy and QoS awareness in different layers of the protocol stack. We propose a QoS based and Energy aware Multi-path Hierarchical Routing Algorithm in wireless sensor networks namely QEMH. In this protocol, we try to satisfy the QoS requirements with the minimum energy via hierarchical methods. Our routing protocol includes two phase. In first phase, performs cluster heads election based on two parameters: node residual energy and node distance to sink. In second phase, accomplishes routes discovery using multiple criteria such as residual energy, remaining buffer size, signal-to-noise ratio and distance to sink. When each node detect an event can send data to the CH as single hop and CH to the sink along the paths. We use a weighted traffic allocation strategy to distribute the traffic amongst the available paths to improve the end to end delay and throughput. In this strategy, the CH distributes the traffic between the paths according to the end to end delay of each path. The end to end delay of each path is obtained during the paths discovery phase. QEMH maximizes the network lifetime as load balancing that causes energy consume uniformly throughout the network. Furthermore employs a queuing model to handle both real-time and non-real-time traffic. By means of simulations, we evaluate and compare the performance of our routing protocol with the MCMP and EAP protocols. Simulation results show that our proposed protocol is more efficient than those protocols in providing QoS requirements and minimizing energy consumption.展开更多
文摘GMPLS(generalized multi protocol label switching)网络中的多约束QoS路由问题是要在诸如带宽、代价和延迟的约束条件下找到一条优化的路径.这个问题通常被认为是一个NP-完全问题.在研究共享风险链路组具有的启发信息的基础上,提出了一种具有共享风险链路启发信息的多约束预计算算法.该算法包含预计算和搜索两个部分.预计算主要是能创建和更新每个节点上的路由表.而后,搜索部分则可以在层次化的结构中选择满足约束条件的优化的路径.大量仿真数据表明,相应的方法能够取得满意的结果,可以有效地解决GMPLS网络中多约束的QoS路由问题.
文摘This paper investigates the performability of hierarchical Wireless Networked Control Systems (WNCS). The WNCS studied can operate in two modes: passive supervisor and active supervisor. It is first shown that the Markov models for both modes are identical. Performability models are then developed and a case study shows how to use these models to help make design decisions. More specifically, it is observed that the performability of a passive supervisor system increases in time while that of an active supervisor system decreases in time.
文摘We present an effective routing solution for the backbone of hierarchical MANETs. </span></span><span><span><span style="font-family:""><span style="font-family:Verdana;">Our solution leverages the storage and retrieval mechanisms of a Distributed Hash Table (DHT) common to many (structured) P2P overlays. Th</span><span style="font-family:Verdana;">e DHT provides routing information in a decentralized fash</span><span style="font-family:Verdana;">ion, while supporting different forms of node and network mobility. We split a flat network into clusters, each having a gateway who participates in a DHT overlay. These g</span><span style="font-family:Verdana;">ateways interconnect the clusters in a backbone network. Two routing </span><span style="font-family:Verdana;">approaches for the backbone are explore</span><span style="font-family:Verdana;">d: floodi</span><span style="font-family:Verdana;">ng and a new solution exploit</span><span style="font-family:Verdana;">ing the storage and retrieval capabilities of a P2P overlay based on a DHT.</span><span style="font-family:Verdana;"> We </span><span style="font-family:Verdana;">implement both approaches in a net</span><span style="font-family:Verdana;">work simulator and thoroughly evaluate th</span><span style="font-family:Verdana;">e performance of the proposed scheme using a range of stati</span><span style="font-family:Verdana;">c and mobile scenarios. We also compare our solution against flooding. The simulation results show that our solution, even in the presence of mobility, achieved well abo</span><span style="font-family:Verdana;">ve 90% success rates and maintained very low and constant round tr</span><span style="font-family:Verdana;">ip times, unlike the flooding approach. In fact, the performance of the proposed </span><span style="font-family:Verdana;">inter-cluster routing solution, in many cases, is comparable to the perfo</span><span style="font-family:Verdana;">rma</span><span style="font-family:Verdana;">nce of the intra-cluster routing case. The ad
文摘In hierarchical networks, nodes are separated to play different roles such as CHs and cluster members. Each CH collects data from the cluster members within its cluster, aggregates the data and then transmits the data to the sink. Each algorithm that is used for packet routing in quality of service (QoS) based applications should be able to establish a tradeoffs between end to end delay parameter and energy consumption. Therefore, enabling QoS applications in sensor networks requires energy and QoS awareness in different layers of the protocol stack. We propose a QoS based and Energy aware Multi-path Hierarchical Routing Algorithm in wireless sensor networks namely QEMH. In this protocol, we try to satisfy the QoS requirements with the minimum energy via hierarchical methods. Our routing protocol includes two phase. In first phase, performs cluster heads election based on two parameters: node residual energy and node distance to sink. In second phase, accomplishes routes discovery using multiple criteria such as residual energy, remaining buffer size, signal-to-noise ratio and distance to sink. When each node detect an event can send data to the CH as single hop and CH to the sink along the paths. We use a weighted traffic allocation strategy to distribute the traffic amongst the available paths to improve the end to end delay and throughput. In this strategy, the CH distributes the traffic between the paths according to the end to end delay of each path. The end to end delay of each path is obtained during the paths discovery phase. QEMH maximizes the network lifetime as load balancing that causes energy consume uniformly throughout the network. Furthermore employs a queuing model to handle both real-time and non-real-time traffic. By means of simulations, we evaluate and compare the performance of our routing protocol with the MCMP and EAP protocols. Simulation results show that our proposed protocol is more efficient than those protocols in providing QoS requirements and minimizing energy consumption.
