MintRoute-HNLB:一种支持负载均衡的无线传感器网络路由协议

针对无线传感器网络中的负载均衡问题,提出并在TinyOS系统上实现了MintRout-HNLB协议算法。Mint-Rout-HNLB引入了热度申明和热点节点规避机制,选择次优父节点分担热点节点的数据转发任务,均衡网络负载,并提出了同级节点路由均衡性能指标SLN-LBEIn作为负载均衡性判据,通过TOSSI M模拟仿真表明Mint-Rout-HNLB比MintRoute协议能有效地实现网络负载均衡,均衡同级节点能量消耗。     

实时响应物联网中基于查询的数据转发方案

在许多基于传感器网络技术的物联网应用中,用户需要快速的查询响应,比如智能交通物联网应用中,行驶在路上的司机即时查询附近的空停车位信息.如何为此类物联网设计一种符合传感器网络特性(如能量有效等)的快速数据转发方案是一项重要的挑战性工作.已有的传感器网络实时数据转发协议大都因未解决好转发断路带来的额外开销、孤立节点处理耗时、难以适应网络拓扑动态变化等关键性问题而未取得理想的实时性效果.为此,该文提出一种新的基于查询的快速数据转发方案,利用查询消息为每个传感器节点建立最快速的数据转发路径(有向无环图),此外文中给出的综合路径代价模型可以均衡网络能量和减少网络拥塞延时,最后设计了贪婪的分布式数据转发算法及其改进算法,并用仿真实验验证了该方案的有效性和高效性.     

Comparative packet-forwarding measurement of three popular operating systems

This papers measures and compares the network performance (with respect to packet forwarding) of three popular operating systems when used in today's Gigabit Ethernet networks. Specifically, the paper compares the performance in terms of packet forwarding of Linux, Windows Server and Windows XP. We measure both kernel- and user-level packet forwarding when subjecting hosts to different traffic load conditions. The performance is compared and analyzed in terms of throughput, packet loss, delay, and CPU availability. Our evaluation methodology is based on packet-forwarding measurement which is a standard and popular benchmark and evaluation methodology to assess the performance of network elements such as servers, gateways, routers, and switches. Our evaluation methodology considers different configuration setups and utilizes open-source software tools to generate relatively high traffic rates. We consider today's typical network hosts of modern processors and Gigabit network cards. Our measurements show that in general Linux exhibits superior overall performance in the case of kernel (or IP) packet forwarding, whereas Windows Server exhibits superior performance in the case of user-level packet forwarding.     

Extending next generation network (NGN) architecture for connection-oriented transport

Next Generation Network (NGN) is the architecture of the International Telecommunication Union-Telecommunication Standardization Sector (ITU-T in short) supporting the provisioning of Quality of Service (QoS)-guaranteed services over different packet transport technologies. Such capability derives from the effectiveness of a dynamic resource control performed by the Resource Admission Control Function (RACF) at service set-up.Control Plane (CP)-enabled connection-oriented transport networks can guarantee the QoS support for new bandwidth-greedy NGN services across the optical transport segment thanks to the ability of automatic path set-up and traffic segregation. But the Internet Engineering Task Force (IETF) standard for the CP in transport networks, i.e., the Generalized Multi-Protocol Label Switching (GMPLS) is not yet included within the NGN supported transport technologies.In this work, we outline architectural guidelines and design strategies for ITU-T RACF employment across GMPLS-controlled networks while providing a viable solution for dynamic resource control that takes into account operational issues for the integration of GMPLS capabilities within NGN architecture (i.e., supported interfaces, actual node capabilities).An NGN prototype implementing the proposed architectural enhancement is also presented as a proof of concept. The prototype highlights how the extended ITU-T NGN can set-up Multimedia over IP (MoIP) services using GMPLS-controlled transport objects.     

基于标签的POF网络虚拟化技术研究

针对SDN新一代转发控制分离技术——协议无感知转发(POF),提出了协议字段全开放的SDN网络虚拟化架构。该架构提出了基于标签的网络虚拟化技术和POF物理交换机流表分配技术,通过网络虚拟化中间件将POF交换机与POF控制器之间传递的消息进行转换,对物理网络中传输的数据进行标签封装,从而区分不同网络切片与虚拟链路的流量信息。与已有的虚拟化中间件Flow Visor、Open Virtex、Co Visor等相比,该虚拟化中间件全面支持POF协议,通过物理网络中的数据的标签化处理,实现了SDN转发平面全字段开放的网络虚拟化。同时,基于该套架构,实现了POF网络虚拟化中间件系统POFHyper Visor,并验证了该POF网络虚拟化中间件系统的功能与性能,经测试,虚拟化消息处理能力损失在17.1%~29.9%。     

Enhancing the security of blockchain-based software defined networking through trust-based traffic fusion and filtration

With the rapid development of Internet-of-Things (IoT), more smart devices can be connected to the Internet, resulting in a dramatic increase of data transmission and communication. Software-Defined Networking (SDN), which separates the control planes and data planes, is considered as a promising solution to provide the scale and versatility necessary for IoT. However, SDN still suffers from several challenges, i.e., the centralized control plane would be a single point of failure. With the wide adoption of blockchain applications, such technologies can have a positive impact on SDN’s performance, i.e., blockchains allow non-confident individuals to interact with each other without the need for a central authority. However, attackers can still inject traffic to influence blockchain nodes from normal operations. Motivated by the recent development of blockchains and SDN, in this work, we focus on blockchain-based SDN and develop BSDNFilter, an IDS-based security mechanism that builds a trust-based filtration by using traffic fusion and aggregation to handle and reduce malicious traffic. Through collaborating with an IT organization, our evaluation in a real blockchain-based SDN environment demonstrates that our BSDNFilter is able to achieve better filtration performance against flooding attacks than similar approaches.     

AVCOL: Availability-aware information aggregation in large distributed systems under uncollaborative behavior

Aggregation of system-wide information in large-scale distributed systems, such as p2p systems and Grids, can be unfairly influenced by nodes that are selfish, colluding with each other, or are offline most of the time. We present AVCOL, which uses probabilistic and gossip-style techniques to provide availability-aware aggregation. Concretely, AVCOL is the first aggregation system that: (1) implements any (arbitrary) global predicate that explicitly specifies any node’s probability of inclusion in the global aggregate, as a mathematical function of that node’s availability (i.e., percentage time online); (2) probabilistically tolerates large numbers of selfish nodes and large groups of colluders; and (3) scales well with hundreds to thousands of nodes. AVCOL uses several unique design decisions: per-aggregation tree construction where nodes are allowed a limited but flexible probabilistic choice of parents or children, probabilistic aggregation along trees, and auditing of nodes both during aggregation as well as in gossip-style (i.e., periodically). We have implemented AVCOL, and we experimentally evaluated it using real-life churn traces. Our evaluation and our mathematical analysis show that AVCOL satisfies arbitrary predicates, scales well, and withstands a variety of selfish and colluding attacks.     

采用Hull树的贪婪地理位置路由算法的设计

地理位置路由算法是指借助节点获得的地理位置信息进行无线传感网络中的路由发现与数据转发工作。本文提出一种基于Hull树的贪婪地理位置路由算法——Greedy Hull Tree Geographic Routing(GHTGR)。通过图形学中凸包的概念,在网络初始阶段分布式地在各节点上建立Hull树以探查网络局部拓扑结构;同时在数据分组的路由转发阶段,通过Hull树内的搜索,寻找下一跳转发节点,完成数据分组的转发传输。通过仿真实验表明,与现有地理位置路由算法相比,该算法能够正确地寻找数据转发路径,有效地减少网络能耗,提高网络传输性能。     

Traffic Engineering for wireless connectionless access networks supporting QoS-demanding media applications

This paper focuses on the problem of optimal QoS Traffic Engineering (TE) in Co-Channel Interference (CCI)-affected power-limited wireless access networks that support connectionless services. By exploiting the analytical tool offered by nonlinear optimization and following the emerging “Decomposition as Optimization” paradigm [1], the approach pursued in this paper allows to develop a resource allocation algorithm that is distributed, asynchronous, scalable and self-adaptive. Interestingly, the proposed algorithm enables each node of the network to distribute its outgoing traffic among all feasible next-hops in an optimal way, as measured by an assigned global cost function of general form. This optimal traffic distribution complies with several subjective as well as objective QoS requirements advanced by the supported media flows and involves only minimum information exchange between neighboring nodes. Furthermore, it allows for load-balanced multiple forwarding paths and it is able to self-perform optimal traffic re-distribution (i.e., re-routing) in the case of failure of the underlying wireless links. Finally, actual effectiveness of the overall proposed algorithm is numerically tested via performance comparisons against both DSDV-based single-path routing algorithms and interference-aware multipath routing algorithms.     

Required extra capacity: A comparative estimation of overprovisioning needed for a classless IP backbone

The benefit of Class-of-Service (CoS) is an important topic in the “Network Neutrality” debate. As part of the debate, it has been suggested that over-provisioning is a viable strategy to meet performance targets of future applications, and that there is no need for to worry about provisioning differentiated services in an IP backbone for a small fraction of users needing better-than-best-effort service. In this paper, we quantify the extra capacity requirement for an over-provisioned classless (i.e., best-effort) network compared to a CoS network providing the same delay or loss performance for premium traffic. We first develop a link model that quantifies the required extra capacity (REC). To illustrate key parameters involved in analytically quantifying REC, we start with simple traffic distributions. Then, for more bursty traffic distributions (e.g., long-range dependent), we find the REC using ns-2 simulations of CoS and classless links. We, then, use these link models to quantify the REC for network topologies (obtained from Rocketfuel) under various scenarios including situations with “closed loop” traffic generated by many TCP sources that adapt to the available capacity. We also study the REC under link and node failures. We show that REC can still be significant even when the proportion of premium traffic requiring performance assurances is small, a situation often considered benign for the over-provisioning alternative. We also show that the impact of CoS on best-effort (BE) traffic is relatively small while still providing the desired performance for premium traffic.     

Cored-Based Tree with Forwarding Regions (CBT-FR); A Protocol for Reliable Multicasting in Mobile Ad Hoc Networks

In this paper we propose a new protocol for reliable multicast in a multihop mobile radio network. The protocol is reliable, i.e., it guarantees message delivery to all multicast nodes even when the topology of the network changes during multicasting. The proposed protocol uses a core-based shared tree. The multicast tree may get fragmented due to node movements. The notion of a forwarding region is introduced which is used to glue together fragments of multicast trees. The gluing process involves flooding the forwarding region of only those nodes that witness topology change due to node mobility. Delivery of multicast messages to mobile nodes is expedited through (i) pushing the message by witness nodes in their forwarding regions and (ii) pulling messages by a mobile node during (re)joining process. Hence, the protocol conserves network bandwidth by using a combination of the push–pull approach and by restricting flooding only to the essential parts of the network that are affected by topology change.  We develop a theoretical model to compute the probability of packet loss (as a function of the mobility rate) for our proposed scheme compared to the the core-based tree protocol (CBT); we also evaluate the effectiveness of forwarding regions as compared to traditional flooding. Our analysis shows that the proposed scheme significantly outperforms CBT.     

无线传感网络数据转发最佳权重选取算法仿真

为了有效提高无线传感网络数据转发的有效性和可靠性,针对传统的数据转发算法存在的数据转发率低、延时长等问题,提出一种基于蚁群优化的无线传感网络数据转发最佳权重选取算法。选择无线传感网络数据节点负载、剩余能量以及数据转发时延作为网络服务性能评价指标,利用熵权系数法自适应地确定评价指标的权重。引入数据转发链路容量和链路距离等因素建立数据转发时延最小的优化模型,利用蚁群算法的节点概率函数机制找出能同时满足时延带宽和数据转发链路容量要求的评价值最高的邻居节点,通过上述节点选取数据转发最优权重,完成数据转发。实验结果表明,所提算法在节点能量消耗、转发延迟、数据转发率等方面都优于现有无线传感网络数据转发算法。     

An energy-efficient,transport-controlled MAC protocol for wireless sensor networks

In wireless sensor networks (WSNs), one major cause of wasted energy is that the wireless network interface is always on to accept possible traffic. Many medium access control (MAC) protocols therefore adopted a periodic listen-and-sleep scheme to save energy, at sacrifice of end-to-end latency and throughput. Another cause is packet dropping due to network congestion, necessitating a lightweight transport protocol for WSNs. In this paper, we suggest a transport-controlled MAC protocol (TC-MAC) that combines the transport protocol into the MAC protocol with the aims of achieving high performance as well as energy efficiency in multi-hop forwarding. Although TC-MAC also works through a periodic listen-and-sleep scheme, it lowers end-to-end latency by reserving data forwarding schedules across multi-hop nodes during the listen period and by forwarding data during the sleep period, all while increasing throughput by piggybacking the subsequent data forwarding schedule on current data transmissions and forwarding data consecutively. In addition, TC-MAC gives a fairness-aware lightweight transport control mechanism based on benefits of using the MAC-layer information. The results show that TC-MAC performs as well as an 802.11-like MAC in end-to-end latency and throughput, and is more efficient than S-MAC in energy consumption, with the additional advantage of supporting fairness-aware congestion control.     

计算机高速互联网中一类基于速率的PD拥塞控制方法

运用现代控制理论和方法,针对计算机高速互联网中最大努力服务交通流即能控交通 流的调节问题,提出了一种基于速率的具有比例加微分(PD)控制器结构的拥塞控制理论和方法． 在单个节点的交通流的模型基础上,运用控制理论中系统稳定性分析方法,讨论如何利用信终端 节点缓冲占有量的比例加微分的反馈形式来调节信源节点的能控交通流的输入速率,从而使被 控网络节点的缓冲占有量趋于稳定.仿真结果显示,在所设计的PD控制方案下,网络的有关性能 较好.     

一类基于速率的PD拥塞控制方法

运用现代控制理论和方法，针对计算机高速互联网中最大努力服务交通流(即能控交通流)的调节问题，提出了一种基于速率的、具有比例加微分(PD)控制器结构的拥塞控制理论和方法。在多个信源节点、单个信终端节点、交通流的模型基础上，运用控制理论中系统稳定性分析方法，讨论如何利用信终端节点缓冲占有量的比例加微分的反馈形式，来调节信源节点的能控交通流(ABR)的输入速率，从而使被控网络节点的缓冲占有量趋于稳定。仿真结果显示，在所设计的PD控制方案下，网络的有关性能较好。     

无线Mesh网络中基于奖励机制的均衡传输方案

针对无线Mesh网络存在自私节点而造成的双向流量的均衡问题,提出了一种基于奖励机制的均衡传输方案。首先,推导出了每个传输访问点(TAP)的双向目标吞吐量。然后,提出一种奖励机制,通过信用币和代币支付策略来鼓励闲置TAP转发数据,同时使网关尽可能均衡地向TAP传输下行数据。在一个具有3个TAP的无线Mesh网络上仿真结果表明,该方法能够在存在自私节点情况下确保双向流量的均衡。     

Robust and dynamic data aggregation in wireless sensor networks: A cross-layer approach

In-network data aggregation is an effective technique to reduce communication cost in wireless sensor networks. Recent studies have focused on two issues respectively: dynamic aggregation to handle event triggered irregular traffic and robust aggregation to handle packet losses. However, how to achieve both the objectives simultaneously, i.e. dynamic and robust aggregation is still not considered. In this paper, by making use of direct support from MAC layer, we propose a cross-layer approach to realize robust and dynamic data aggregation. A new MAC protocol, DA-MAC is delicately designed to serve such purpose. With channel contention information obtained from DA-MAC, a node can dynamically determine where and when to do aggregation. To cope with packet losses, a virtual overlay, Rings is adopted to forward one packet to multiple nodes. We have conducted numerical analysis to optimize the key parameters and implemented our design in TinyOS based sensor networks. Performance evaluation though simulations and experiments shows that our approach can handle both traffic dynamics and packet losses, with less cost than similar solutions.     

一种基于节点位置余弦相似度的机会网络转发算法

针对机会网络中数据送达率较低的问题,文中根据节点历史接触信息即节点相遇次数、相遇时间长度、节点关系稳定性来计算节点转发效用值。首先选择通信范围内效用值最大的邻居节点作为初始转发节点,再根据余弦相似度选择其他转发节点,使得转发节点能够尽可能均匀地分布。在此基础上,提出一种基于节点位置余弦相似度的机会网络转发算法(Opportunistic Network forwarding algorithm based on Node Cosine Similarity,ONNCS)。该算法使得转发节点能够均匀地分布,因此数据报文能够尽快地被转发到目的节点。实验结果表明,ONNCS具有较高的转发成功率和较低的转发能耗,转发成功率高出其他算法5%～8%。     

适合无线自组网的QOS体系结构研究

随着移动无线网络技术的发展和多媒体业务的普及,在无线自组网上保障业务的服务质量（QoS）已成为备受关注和急需解决的热点问题之一。文中提出一种适用于无线自组网的QoS体系——FQAw,试图提升无线自组网的QoS保障能力。首先,说明了在无线自组网中采用QoS体系结构的必要性。然后,详细说明和分析FQAW体系结构的设计理念、网络结构、功能部件和相关机制。分析表明基于分簇网络结构的FQAW可提高无线自组网的可扩展性和服务质量保障水平,但是还需借助于计算机模拟和现场试验等方法来评价QoS网络体系结构的优劣。     

Mobile Fog Computing by Using SDN/NFV on 5G Edge Nodes

Fog computing provides quality of service for cloud infrastructure. As the data computation intensifies, edge computing becomes difficult. Therefore, mobile fog computing is used for reducing traffic and the time for data computation in the network. In previous studies, software-defined networking (SDN) and network functions virtualization (NFV) were used separately in edge computing. Current industrial and academic research is tackling to integrate SDN and NFV in different environments to address the challenges in performance, reliability, and scalability. SDN/NFV is still in development. The traditional Internet of things (IoT) data analysis system is only based on a linear and time-variant system that needs an IoT data system with a high-precision model. This paper proposes a combined architecture of SDN and NFV on an edge node server for IoT devices to reduce the computational complexity in cloud-based fog computing. SDN provides a generalization structure of the forwarding plane, which is separated from the control plane. Meanwhile, NFV concentrates on virtualization by combining the forwarding model with virtual network functions (VNFs) as a single or chain of VNFs, which leads to interoperability and consistency. The orchestrator layer in the proposed software-defined NFV is responsible for handling real-time tasks by using an edge node server through the SDN controller via four actions: task creation, modification, operation, and completion. Our proposed architecture is simulated on the EstiNet simulator, and total time delay, reliability, and satisfaction are used as evaluation parameters. The simulation results are compared with the results of existing architectures, such as software-defined unified virtual monitoring function and ASTP, to analyze the performance of the proposed architecture. The analysis results indicate that our proposed architecture achieves better performance in terms of total time delay (1800 s for 200 IoT devices), reliability (90%), and satisfaction (90%).