测试系统的SpaceWire节点控制器的研发

高分辨率对地观测系统是《国家中长期科学和技术发展规划纲要(2006~2020年)》所确定的16个重大专项之一该系统需要高效率、高可靠性的总线来满足航天器的数据的分布式处理能力。SpaceWire总线是欧空局(ESA)提出新一代智能总线,具备在高可靠性、高安全环境下提供高速通信能力的总线系统。目前,国内大多停留在对SpaceWire相关IP设计及上层协议的开发应用方面,对于SpaceWire设备的性能如何、是否符合SpaceWire总线标准,缺少相应的设备支持。本文基于测试设备的需要,选用标准的SpaceWire IP核,通过扩展时间码功能,设计了一款具有测试SpaceWire标准一致性以及误码率、网络延时的SpaceWire节点控制器设计。     

核心路由器转发体系演进研究

转发体系是核心路由器的关键模块,承担报文转发和网络层协议实现的功能.本文研究路由器转发体系的发展演化,通过研究基于CPU、ASIC、FPGA和NP等技术的转发体系,详细分析了各种转发体系的特点,为路由器结构设计和实现提供参考.     

IP电话及IP电话计费器的检定

一、IP电话简介IP电话,更准确地说应该是数据网络电话。IP(Internet Protocol)本来只是Internet的网络层协议和重要的技术基础。由于它代表了无连接通信方式的本质特性,成为区别于传统通信方式的基本标志。语音信息由固定电话或手机通过本地程控交换机或移动交换机进入因特网并转换成数字信号,以一个个数据包的形式在因特网中传输。这是一个路由器加专线(光缆)的存储转发型网络。IP协议实质上     

解析媒体矩阵(MediaMatrix)(六十一)高性能媒体数据流传输解决方案AVB(1)

我们花费了将近一年的时间学习了基于三层(IP网络层)网络音频传输技术Dante,基本上了解了支持这种技术的两个最基本的技术,一个是IEEE1588精密同步时钟协议,另一个就是零配置方案--Zeroconf技术.     

基于数据融合的无线传感器网络路由协议

在无线传感器网络中,各个协议层的数据融合技术都有各自的算法,而网络层的数据融合技术则主要是与路由协议相结合。本文根据数据融合和路由协议的基本原理,分析了几种结合路由协议的数据融合算法,并对这几种算法进行分析和比较。     

数字化医院网络中负载均衡技术的应用

随着以太网技术的不断成熟,数字化医院网络业务量的迅速增加,在网络吞吐量、网络数据处理能力以及业务服务提供能力出现了瓶颈。解决此问题主要通过两种方式实现:带宽扩容和负载均衡。带宽扩容实现难度大、投资成本比较高,通常采用廉价、透明的负载均衡技术。通常负载均衡技术有数据链路层的负载均衡,主要是通过链路聚合协议,如LACP等;网络层借助于路由协议实现等开销(或者不等开销)路径上的负载均衡;核心服务区的集群技术。     

星载SpaceWire总线及其开发测试技术

作为一项专门面向星载应用的高速数据传输的总线技术,SpaceWire现已被ESA,NASA,JAXA以及其它实体广泛的使用,是已被验证的成熟技术。SpaceWire提供简单适用的标准接口,可以根据应用要求灵活多变的配置最合适的体系结构,同时SpaceWire技术的不断发展提供了更多更强大的功能。现有SpaceWire相关宇航级芯片以及被广泛验证过的IP核可以用来开发SpaceWire设备及系统:并且有一系列的开发测试设备可以用来检测、测试或者分析评估SpaceWire设备、链路和网络。     

基于IPv6的PIM-SMv2协议的设计与实现

在新一代互联网中,支持组播已成为对路由器的基本要求。PIM-SM是一个不依赖于某一特定单播路由协议的组播路由协议,为组播数据转发提供路由信息。本文介绍了高性能：IPv6路由器协议栈软件中基于原始套接字(Raw Socket)通信机制的PIM—SMv2协议的设计与实现,并搭建实验环境对实现的系统进行了测试。实验结果表明,该系统已具备IPv6组播功能。     

网络通信中动态路由协议的应用和漏洞的防范措施

计算机网络通信系统作为一个复杂的系统,路由器在每个网络中起到关键的作用,如果一方路由被破坏或者一方路由被成功的欺骗,网络的完整性将受到严重的破坏,存在着man-in-the-middle攻击、拒绝服务攻击、数据丢失、网络整体性破坏和信息被嗅探等攻击,很多公司的路由器都有自主开发的动态路由协议,而这些协议在网络通信中也有重要的作用,基于对这种路由协议的关注,路由和路由协议的漏洞是亟待解决的问题,如RIP(路由信息协议)、IGP(内部网关协议)、SPF(最短路径优先协议)。     

RIP路由协议分析及配置简述

介绍RIP(Routing Information Protocol)路由协议的基本内容,分析RIP协议的工作原理,路由环路的产生及解决方法,通过实验阐述如何在路由器上配置RIP协议。     

Energy Efficient Ambience Awake Routing with OpenFlow Approach

A major problem in networking has always been energy consumption. Battery life is one parameter which could help improve Energy Efficiency. Existing research on wireless networking stresses on reducing signaling messages or time required for data transfer for addressing energy consumption issues. Routing or Forwarding packets in a network between the network elements like routers, switches, wireless access points, etc., is complex in conventional networks. With the advent of Software Defined Networking (SDN) for 5G network architectures, the distributed networking has embarked onto centralized networking, wherein the SDN Controller is responsible for decision making. The controller pushes its decision onto the network elements with the help of a control plane protocol termed OpenFlow. Decentralized networks have been largely in use because of their ease in physical and logically setting the administrative hierarchies. The centralized controller deals with the policy funding and the protocols used for routing procedures are designated by the decentralized controller. Ambience Awake is a location centered routing protocol deployed in the 5G network architecture with OpenFlow model. The Ambience Awake mechanism relies on the power consumption of the network elements during the packet transmission for unicast and multicast scenarios. The signalling load and the routing overhead witnessed an improvement of 30% during the routing procedure. The proposed routing mechanism run on the top of the decentralized SDN controller proves to be 19.59% more efficient than the existing routing solutions.     

Route computation in large road networks: a hierarchical approach

The optimal route between a given origin and destination needs to be computed in a fast and efficient manner in dynamic route guidance systems. Conventional routing algorithms have been found to be inadequate when applied directly to large road networks. Algorithms based on the concept of hierarchical abstraction make use of the knowledge about the road network to reduce search and provide near-optimal solutions. A generic procedure is presented for organising a given road network as a multiple-layer hierarchy. An efficient hierarchical routing algorithm is proposed, which breaks down the route search into a number of individual searches in small sub-networks. The algorithm incorporates a heuristic layer-switching technique to improve its performance without compromising the accuracy. The hierarchical routing algorithm was tested on the road network of Singapore and the solutions were found to be comparable to the optimal least-cost paths.     

The effects of routing flexibility in a multi-stage pull-type system

The pull-type manufacturing system is known for its need for a frozen schedule, balanced work load and inability to handle fluctuations in demand. But today research and development are addressing ways to handle a pull-type system to accommodate greater fluctuations. One approach is to design the system with machines that have a greater routing flexibility in what work they can perform. However, most of the existing literature dealing with routing flexibility has primarily been devoted to the push-type production systems. This research examined the effects of routing flexibility for a multi-stage kanban-controlled pull-type system.     

基于Ad hoc无线网络的AODV路由协议仿真

利用以Ubuntu为平台的NS2网络仿真器,对AODV路由协议进行仿真.通过分析不同仿真场景的仿真数据,绘制出相应的仿真结果对比图,并对AODV路由协议进行了性能分析.仿真结果表明,在数据流不断增加的情况下,网络平均吞吐量、归一化路由开销以及端到端平均时延等性能指标会相应下降,得出了AODV路由协议适合于中小规模且发包率不高的网络场合的结论.     

The QKD network: model and routing scheme

Quantum key distribution (QKD) technology can establish unconditional secure keys between two communicating parties. Although this technology has some inherent constraints, such as the distance and point-to-point mode limits, building a QKD network with multiple point-to-point QKD devices can overcome these constraints. Considering the development level of current technology, the trust relaying QKD network is the first choice to build a practical QKD network. However, the previous research didn’t address a routing method on the trust relaying QKD network in detail. This paper focuses on the routing issues, builds a model of the trust relaying QKD network for easily analysing and understanding this network, and proposes a dynamical routing scheme for this network. From the viewpoint of designing a dynamical routing scheme in classical network, the proposed scheme consists of three components: a Hello protocol helping share the network topology information, a routing algorithm to select a set of suitable paths and establish the routing table and a link state update mechanism helping keep the routing table newly. Experiments and evaluation demonstrates the validity and effectiveness of the proposed routing scheme.     

Traffic Engineering in Dynamic Hybrid Segment Routing Networks

The emergence of Segment Routing (SR) provides a novel routing paradigm that uses a routing technique called source packet routing. In SR architecture, the paths that the packets choose to route on are indicated at the ingress router. Compared with shortest-path-based routing in traditional distributed routing protocols, SR can realize a flexible routing by implementing an arbitrary flow splitting at the ingress router. Despite the advantages of SR, it may be difficult to update the existing IP network to a full SR deployed network, for economical and technical reasons. Updating partial of the traditional IP network to the SR network, thus forming a hybrid SR network, is a preferable choice. For the traffic is dynamically changing in a daily time, in this paper, we propose a Weight Adjustment algorithm WASAR to optimize routing in a dynamic hybrid SR network. WASAR algorithm can be divided into three steps: firstly, representative Traffic Matrices (TMs) and the expected TM are obtained from the historical TMs through ultra-scalable spectral clustering algorithm. Secondly, given the network topology, the initial network weight setting and the expected TM, we can realize the link weight optimization and SR node deployment optimization through a Deep Reinforcement Learning (DRL) algorithm. Thirdly, we optimize the flow splitting ratios of SR nodes in a centralized online manner under dynamic traffic demands, in order to improve the network performance. In the evaluation, we exploit historical TMs to test the performance of the obtained routing configuration in WASAR. The extensive experimental results validate that our proposed WASAR algorithm has superior performance in reducing Maximum Link Utilization (MLU) under the dynamic traffic.     

Reactive and proactive routing in labelled optical burst switching networks

Optical burst switching architectures without buffering capabilities are sensitive to burst congestion. The existence of a few highly congested links may seriously aggravate the network throughput. Proper network routing may help in congestion reduction. The authors focus on adaptive routing strategies to be applied in labelled OBS networks, that is, with explicit routing paths. In particular, two isolated alternative routing algorithms that aim at network performance improvement because of reactive route selection are studied. Moreover, a nonlinear optimisation method for multi-path source-based routing, which aims at proactive congestion reduction is proposed. Comparative performance results are provided and some implementation issues are discussed.     

An expert system for network management control

Abstract

Due to the varying time and the complexity of the commercial telecommunication network configuration, routing of the communication traffic becomes very important for telecommunication systems. No one can keep in mind all the complex routing plans used in networks, so it is hard to quickly take proper actions while the switching node is being blocked.

In this paper, we propose an expert system which can collect traffic data, monitor network status, reason and take appropriate actions for extreme traffic congestion on a network just as a network management expert can do. It would certainly streamline the whole network control procedure, and. provide dynamic routing functions based on the original static routing method adopted in Taiwan. It does improve both network efficiency and network reliability.     

EAMTR: energy aware multi-tree routing for wireless sensor networks

IEEE 802.15.4 is the prevailing standard for low-rate wireless personal area networks. It specifies the physical layer and medium access control sub-layer. Some emerging standards such as ZigBee define the network layer on top of these lower levels to support routing and multi-hop communication. Tree routing is a favourable basis for ZigBee routing because of its simplicity and limited use of resources. However, in data collection systems that are based on spanning trees rooted at a sink node, non-optimal route selection, congestion and uneven distribution of traffic in tree routing can adversely contribute to network performance and lifetime. The imbalance in workload can result in hotspot problems and early energy depletion of specific nodes that are normally the crucial routers of the network. The authors propose a novel light-weight routing protocol, energy aware multi-tree routing (EAMTR) protocol, to balance the workload of data gathering and alleviate the hotspot and single points of failure problems for high-density sink-type networks. In this scheme, multiple trees are formed in the initialisation phase and according to network traffic, each node selects the least congested route to the root node. The results of simulation and performance evaluation of EAMTR show significant improvement in network lifetime and traffic distribution.     

Multi-level supply chain network design with routing

Recently, the multi-level and multi-facility industrial problem in supply chain management (SCM) has been widely investigated. One of the key issues, central to this problem in the current SCM research area is the interdependence among the location of facilities, the allocation of facilities, and the vehicle routing for the supply of raw materials and products. This paper studies the supply chain network design problem, which involves the location of facilities, allocation of facilities, and routing decisions. The proposed problem has some practical applications. For example, it is necessary for third party logistics (3PL) companies to manage the design of the network and to operate vehicle transportation. The purpose of this study is to determine the optimal location, allocation, and routing with minimum cost to the supply chain network. The study proposes two mixed integer programming models, one without routing and one with routing, and a heuristic algorithm based on LP-relaxation in order to solve the model with routing. The results show that a developed heuristic algorithm is able to find a good solution in a reasonable time.