IPv6网络环境中的多约束QoS路由算法

充分利用IPv6支持QoS的潜能,设计了一种基于扩散的多约束QoS路由算法。算法中利用IPv6数据包基本报头中的流标签字段唯一标识业务流并加速数据流的包分类,利用扩展报头中的逐跳扩展头记录业务流需求并完成接入控制,利用路由头记录扩散包的转发路径并实现及时反馈,解决民IPv4扩散算法很难同时支持多度量参数、很难及时反馈等问题,提高了实时流数据包的转发效率。     

Congestion Adaptive Routing in Mobile Ad Hoc Networks

Mobility, channel error, and congestion are the main causes for packet loss in mobile ad hoc networks. Reducing packet loss typically involves congestion control operating on top of a mobility and failure adaptive routing protocol at the network layer. In the current designs, routing is not congestion-adaptive. Routing may let a congestion happen which is detected by congestion control, but dealing with congestion in this reactive manner results in longer delay and unnecessary packet loss and requires significant overhead if a new route is needed. This problem becomes more visible especially in large-scale transmission of heavy traffic such as multimedia data, where congestion is more probable and the negative impact of packet loss on the service quality is of more significance. We argue that routing should not only be aware of, but also be adaptive to, network congestion. Hence, we propose a routing protocol (CRP) with such properties. Our ns-2 simulation results confirm that CRP improves the packet loss rate and end-to-end delay while enjoying significantly smaller protocol overhead and higher energy efficiency as compared to AODV and DSR     

针对大规模无线多跳网络的鱼眼机会路由协议

考虑到无线网络中广播特性、丢包特性、节点移动等对网络性能的影响,提出一种针对大规模无线多跳网络的鱼眼机会路由协议。在机会路由的基础上加入鱼眼技术,减少链路状态更新信息。在鱼眼路由表中加入链路传输概率,得到转发列表,并且简化机会路由协议的报文头结构,从而实现高效的数据传输。NS2仿真结果表明,该协议能降低网络端到端延时,提高网络吞吐量。     

三维水声传感器网络中高效路由协议的研究

近年来,三维水声传感器网络在学术界和工业界引起了极大的关注.在被监测海域部署三维水声传感器网络,可以解决二维水声传感器网络节点无法充分观测的问题.为了实现三维水声传感器网络在新环境中的水下监测,需要解决一系列的问题.其中,由于监测区域环境的限制以及水声传感器节点的特殊性,需要设计高效的路由协议来保证数据包在各节点之间正确转发.首先提出一种基本地理位置路由协议.在此基础上,设计一种自适应路由协议,以较好地适应三维水声传感器网络中部分节点失效的情况.通过仿真实验发现,自适应路由协议可以在数据包传送率、端到端延时和网络吞吐量指标上达到平衡,而基本地理位置路由协议在端到端延时指标上可获得更好的性能.     

无线移动自组织网路由协议性能研究

路由是无线移动自组织网的关键技术之一。目前已经提出的MANET路由协议有很多种,因此如何针对一定应用场景选择一个最佳的路由协议,是人们十分关心的一个问题。该文对已经通过IETF认可的三种MANET路由协议：DSR、AODV和OLSR进行了仿真对比分析。设计了大量的场景,通过对路由协议的分组传送率、端到端时延和所选路径长度等指标的比较,得出了在不同的网络环境下MANET最佳路由协议选择方案。仿真中发现同是采用按需的路由发现策略的DSR和AODV在高移动、高负荷的网络环境下的性能存在较大差异,对此原因进行了深入分析,并根据分析对DSR提出了改进方案。     

智能电网中电力线通信网络负载均衡的机会路由协议

针对智能电网（SG）中电力线通信（PLC）网络中负载均衡的问题,提出了一个自适应机会路由协议——负载均衡的机会路由协议（LBORP）。在LBORP中,所有收到数据包的候选转发节点都有机会参与到数据包的转发中,不再局限于一条路由路径,避免了流量仅从一条链路经过导致的负载不均衡现象;而且候选转发节点的转发优先级不仅考虑到转发节点到目的节点的距离,还考虑到了PLC链路的不稳定性以及流量的变化。除此之外,在LBORP中采用一种隐式确认方案,进一步减少协议的端到端时延。在仿真实验中,与基于有序树的PLC路由协议（PLC-TR）和PLC机会路由协议（PLC-OR）相比,LBORP在时延上分别降低了19.7%和45.8%,在丢包率上分别降低了23.4%和32.5%。实验结果表明,LBORP能够实现网络的负载均衡,提升网络的可靠性并减小端到端时延。     

车载网中一种利用静态节点辅助的路由方法

车载自组织网络(Vehicular Ad Hoc Network,VANET)越来越引起人们的广泛关注,虽然该网络与传统的自组织网络有类似的地方,比如网络中的节点可以自组织和自管理。但是它有自己重要特征:网络中的节点具有很快的移动速度,由于这种高速的移动,造成车载网络拓扑结构频繁的变化,导致网络中多跳路由的频繁断开,进而对路由的可靠性和数据传输的质量带来很大的挑战。路由选择是实现VANET的关键。我们提出一种利用静态节点辅助的路由方法(Static-Node Assisted Routing,SNAR)来提高数据包的传输效率。模拟实验显示,SNAR在端到端延时等方面要优于其它的多跳路由方法。     

无线传感网络中基于自动学习机的数据传输策略

尽管多径路由能够提高数据包传输成功率,但是其增加参与数据传输的节点数,提升了网络能耗。为此,提出基于自动学习机的单径路由(Single Path-based Learning Automation Routing,SPLAR)。设计SPLAR路由的主旨在于以最少能耗实现数据包传递率的最大化和端到端传输时延的最小化。通过自动学习机构建每个节点的动作集,并依据环境学习更新每个动作的概率。再选择具有最高概率的动作传输数据。仿真结果表明,提出的SPLAR路由在数据包传递率和端到端传输时延具有较好的性能。     

On the implications of routing metric staleness in delay tolerant networks

Delay Tolerant Network (DTN) routing addresses challenges of providing end-to-end service where end-to-end data forwarding paths may not exist. The performance of current DTN routing protocols is often limited by routing metric “staleness”, i.e., routing information that becomes out-of-date or inaccurate because of long propagation delays. Our previous work, ParaNets, proposed a new opportunistic network architecture in which the data channel is augmented by a thin end-to-end control channel. The control channel is adequate for the exchange of control traffic, but not data. In this paper we present Cloud Routing, a routing solution for the ParaNets architecture. We motivate the need for such a solution, not only because of stale routing metrics, but also because of congestion that can occur in DTNs. Unable to use up-to-date routing metrics to limit congestion, existing DTN routing solutions suffer from low goodput and long data delivery delays. We show how Cloud Routing avoids congestion by smart use of forwarding opportunities based on up-to-date routing metrics. We evaluate our solution using extensive OPNET simulations. Cloud Routing extends network performance past what is currently possible and motivates a new class of globally cognizant DTN routing solutions.     

Quality of Service Support in RPL Networks: Standing State and Future Prospects

The development of IP-based Internet of Things (IoT) networks would facilitate more effective end-to-end IP network architectures, but it remains a challenge. Network routing needs to be effectively addressed in the IoT environments of scarce computational and energy resources. Accordingly, the Internet Engineering Task Force (IETF) has specified the IPv6 Routing Protocol for Low Power and Lossy Network (RPL) to provide a bespoke IPv6-based routing framework for IoT networks. However, RPL comes with no Quality of Service (QoS) support which is an essential requirement for many IoT applications. The network research community has introduced a number of research proposals enhancing RPL with different QoS solutions. This paper presents a review of these proposed solutions and aims to establish a firm understanding of recent QoS developments for RPL and possible areas for future IoT routing research. The focus is on comprehending the protocol and networking properties that can affect QoS performance in RPL networks. Consideration is also given to different objective functions developed for addressing varying QoS aspects such as throughput, delay, and packet loss. RPL is also extended in a number of QoS solutions following different approaches at the MAC, network, and application layers. However, there is still a need for further developments to address effective QoS support, particularly for dynamic RPL networks.     

无线传感网中数据传输延时优化的路由协议

针对无线传感器网络中存在的数据包丢失严重以及端到端延时较高的问题,提出了一种数据传输延时优化的路由协议（RPODTD）。首先,根据数据包传输结果对信道探测情况进行分类,引入有效探测占比与传输效率作为节点的评价指标;然后,通过实际延时以及理论延时的差值估算数据包的排队延时;最后,给定最大和最小排队延时阈值,根据排队延时所属的区间判断是否更改传输路径。在OMNeT++上进行的仿真实验中,与基于链路质量和延时的复合负载均衡路由协议（ComLoB）和拥塞避免多路径路由协议（CA-RPL）相比,RPODTD节点的平均端到端延时分别降低了78.87%和51.81%,节点丢包率分别降低了40.71%和68.43%,节点的死亡率分别降低了25.42%和44.62%。仿真结果表明,RPODTD能有效地减少端到端延时,降低丢包率,延长网络生命周期。     

A fuzzy queue-aware routing approach for wireless mesh networks

Recent advances in Wireless Mesh Networks (WMNs) have overcome the drawbacks of traditional wired and ad-hoc networks and now they are seen as a means of allowing last mile communications with quality level assurance in Future Multimedia Systems. However, new routing schemes are needed to provide end-to-end Quality of Service (QoS) and Quality of Experience (QoE) support for delay/loss/jitter-sensitive multimedia applications. The well-known OLSR (Optimized Link State Routing) protocol with ETX (Expected Transmission Count) metric brings many benefits to the path selection process, but has a drawback with regard to queue availability management, which reduces the system performance. This problem is caused when OLSR-EXT control messages are exchanged and the queues of mesh routers along the end-to-end communication path are overloaded. As a result, multimedia-related packets will suffer from loss/delay/jitter and the overall system performance will decrease. This paper proposes the Optimized Link State Routing-Fuzzy ETX Queue (OLSR-FEQ) protocol to overcome the limitations of OLSR-ETX regarding queue availability, QoS and QoE assurance. OLSR-FEQ optimizes network and user-based parameters by coordinating queue availability, QoS and fuzzy issues in the routing decision process as a way of allocating the best paths for multimedia applications. Performance evaluations were carried out with the Network Simulator (NS-2.34) to show the benefits of the proposed solution when compared with existing routing schemes, namely OLSR-ETX, OLSR-FLC, OLSR-MD and HWMP (IEEE 802.11s standard), regarding QoS (unsuccessful packet delivery and throughput) and QoE (PSNR, SSIM, VQM and MOS) parameters.     

WSNs中基于可变夹角动态路由的源位置隐私保护方案

2014年,Spachos等人提出了保护原节点位置隐私的基于夹角的动态路由方案(ADRS),但此方案是对固定夹角区域进行数据传输,不能动态改变夹角给出最优路径。为了进一步增强源节点位置隐私安全,提出动态地改变ADRS中固定夹角的新方案——基于可变夹角的动态路由方案(VADRS)。该方案通过对每一跳选择最优角度进行数据传输,改进了ADRS的安全性能。实验表明,在不显著增加网络平均端到端延迟下,新方案能够延长网络的平均安全周期,增强源节点位置隐私的安全性。     

A new approach for delay-constrained routing

Delay-constrained routing protocols are used to find paths subject to a delay constraint while efficiently using network resources. Many of the delay-constrained routing protocols that have been proposed in the literature give priority to cost minimization during the path computing process. With this approach, paths with end-to-end delays too close to the delay constraint are obtained. We believe that such paths are prone to delay constraint violations during load variations in the network. The root of such violations can be found in the imprecision of delay information during the routing process. In this paper, we propose a new approach for delay-constrained routing which captures the tradeoff between cost minimization and the risk level regarding to the delay constraint. We propose a protocol called Parameterized Delay-Constrained Routing protocol that implements our approach using a simple and efficient parameterized selection function. We expand this work to multicasting by proposing three new delay-constrained multicast routing protocols based on the source (Naïve), destination (Greedy) and mixed multicast routing techniques. Our simulations show that our protocols produce paths and trees which are stable, less risky and suitable for various network conditions.     

A pulse switching paradigm for ultra low power cellular sensor networks

This paper presents a novel energy-efficient and fault-tolerant pulse switching protocol for ultra-light-weight wireless cellular network applications. The key idea of pulse switching is to abstract a single pulse, as opposed to multi-bit packets, as the information exchange mechanism. In this paper it is shown to be sufficient for event and target tracking applications with binary sensing in terms of cellular localization. Event monitoring and target tracking with conventional packet transport can be prohibitively energy-inefficient due to the communication, processing, and buffering overheads of the large number of bits within a packet’s data, header, and preambles. Additionally, both of them can be unreliable without protection from errors and faults occurrence. The paper presents a joint MAC and Routing architecture for pulse switching with a novel cellular event localization in the presence of errors and faults. Through analytical modeling and simulation experiments, it is shown that cellular pulse switching can be an effective means for event based networking, which can potentially replace the packet transport when the information is binary in nature.     

最小路径负载度路由协议的研究

DSR协议是Ad hoc网络中典型的路由协议,DSR协议中路由选择策略是基于最短路径的,并未考虑路径的通信量和节点负载等因素,网络中数据流易集中于某些链路,这些链路上的节点承担相对较大的通信量,从而形成热点区域。热点区域的形成会缩短网络的寿命,并且会增加数据包的平均端到端时延,甚至影响数据包的投递率。为了解决上述问题,提出了基于路径负载度的动态源路由协议（LBDSR）,在路由选择时综合考虑了路径长度和路径繁忙度两个因素,有效地解决了热点区域问题,并减小网络中数据包的平均端到端时延,可以有效提高网络的负载平衡性能,延长网络寿命。     

车载网中一种基于链路稳定度的路由方法

车载自组织网络VANET(vehicular ad hoc network)由于车辆高速移动性、分布不均匀、运动行为受交通环境限制等因素的影响,使得VANET具有网络拓扑结构变化频繁、传输信号受干扰大、网络易于断裂等固有特性。路由选择是VANET的重要组成部分。如何选择下一跳节点是实现路由方法的关键,链路稳定度是衡量VANET性能的重要因素。本文通过计算预期路径的链路稳定度来选择下一跳节点,提出一种基于链路稳定度的路由方法。实验结果表明与传统的AODV相比,本文提出的方法在端到端延时,数据包的传递率等方面有较大的提高。     

基于改进Dijkstra算法的配用电通信网流量调度策略

针对配用电通信网中数据汇聚易产生拥塞的问题,提出了一种复合边权值流量调度路由算法。首先,依据跳数建立节点分层模型;然后,划分配用电业务优先级和节点拥塞等级;最后,以跳数、流量负载率和链路利用率为综合指标计算边权值,对需要流量调度的节点根据改进的Dijkstra算法进行路由选择,同时对重度拥塞节点按照配用电业务优先级进行调度。与最短路径（SPF）算法和贪婪背压算法（GBRA）相比,在数据生成率为80 kb/s时,所提算法紧急型业务丢包率分别减少了81.3%和67.7%,关键型业务丢包率分别减少了79%和63.8%。仿真结果表明,所提算法能有效缓解网络拥塞,提高网络有效吞吐量,降低网络端到端时延和高优先级业务的丢包率。     

基于逐跳链接的AODV本地路径修复研究

移动Ad Hoc网络作为一种无线对等自组织网络,具有组网容易、节点可自主移动等特点。无线网络本身的特点以及移动Ad Hoc网络中网络拓扑的动态变化特性使得引起网络故障的原因更加多样,使得保证网络服务质量更加困难。文中针对网络断链问题,基于AODV协议路径修复算法进行研究,提出一种在断点处向下游二跳节点逐跳发起链接请求的路径修复方案。仿真结果表明,改进后的算法能有效减少端到端的平均时延,提高分组投递率,从而达到较稳定的网络服务质量。     

动态源路由协议(DSR)在Linux下的实现

动态源路由协议(DynamicSourceRoutingProtocol,DSR)是由移动节点组成的多跳无线AdHoc网络犤3,4犦中一种简单和行之有效的路由协议犤1犦。协议允许任一结点动态发现到达AdHoc网络中其它任意节点的路由,所有的路由信息由DSR自动地进行维护。每个DSR头部都携带了到达目的节点的完整的路由跃点列表(hoplist),中间节点只需简单地对分组进行转发即可。同时DSR协议完全按需(on-demand)的特性可以显著减少路由协议的开销,节省了电池能量,减少了分组冲突的概率并减少了潜在的大规模的路径更新信息的传播。使用DSR协议可以实现AdHoc网络的完全的自组织和自配置而无需任何已经存在的网络基础设施。论文详细论述了DSR路由协议在Linux操作系统下借助Netfilter的实现。