光分组交换系统网管设计与实现

介绍了一种光分组交换网的网络管理系统设计与实现.所有的核心节点和边缘节点的控制模块都采用FPGA实现,代理端和管理端采用了简单网络管理协议(Simple Network Management Protoc01,SNMP),提供了图形化的用户界面,实现了配置、性能、故障和安全管理.该系统能够使光分组交换网络稳定、高效地运行.     

北电网络推出OPTera Connect HDX新一代光交换机

北电网络近日宣布在中国正式推出OPTera ConnectHDX新一代光传输交换机。这一业界领先的新一代多太比特级光传输节点设备,通过先进的软件技术实现智能化的大容量端到端的传输带宽管理,可望帮助中国的电信运营商实现高效网络管理,赢取竞争优势。OPTeraConnect HDX是一种多太比特级的智能光传输节点设备,它通过北电网络Preside网络管理系统实现智能化的大容量端到端的智能光交换,能够提供空前的网络扩展能     

基于光宽带端到端智慧运营的光终端全自动开通方法

目前光宽带端到端运营过程中PON光终端录入LOID配置采用人工或者半人工的方式实现,尚无方法和系统真正实现光终端全自动开通.要实现自动开通要求包括业务自动开通局内施工自动化、终端实现即插即用,满足运营维护一体化、终端市场化的需求.提出PON光终端全自动开通的方法和系统,可以有效解决上述“临门一脚”问题,提升光网络端到端智慧运营能力,减少资源浪费,提升用户感知.     

一种支持QoS特性的SpaceFibre接口设计与实现

为了满足航天星载系统中音视频、图像等多样化、复杂化业务数据的无冲突高速传输,以及满足控制信息的实时处理,并实现星载系统SpaceWire-SpaceFibre网络构建,提出了一种支持服务质量(QoS)特性的SpaceFibre接口设计与实现方案。该SpaceFibre接口支持SpaceFibre协议和SpaceWire包层协议,支持带宽预留、优先级和时隙调度QoS机制配置,支持64个时隙和系统时隙同步更新,可同时支持4种业务数据的无冲突和确定性传输,带宽利用率达90%以上。     

北电网络推出OPTeraConnectHDX新一代光交换机

近日 ,北电网络宣布在中国正式推出ＯＰＴｅｒａＣｏｎｎｅｃｔＨＤＸ新一代光传输交换机。这一业界领先的新一代多太比特级光传输节点设备通过先进的软件技术实现智能化的大容量端到端的传输带宽管理 ,可户帮助中国的电信运营商实现高效网络管理 ,赢取竞争优势。作为构建下一代全光网的关键平台 ,ＯＰＴｅｒａＣｏｎｎｅｃｔＨＤＸ是一种多太比特级性能的光传输节点设备 ,它通过北电网络Ｐｒｅ ｓｉｄｅ网络管理系统实现智能化的大容量端到端的智能光交换。ＯＰＴｅｒａＣｏｎｎｅｃｔＨＤＸ能够提供空前的网络扩展能力和业务处理能力 ,带…     

光传送网中的信令网

从光网络管理和控制机制的演变和发展提出了光信令网的概念,分析了光信令网链路及 节点的实现方式和MPλS网络中的信令机制,并着重阐述了通用光信令网(GMPLS)。     

认知无线网络中一种新的反压式传输控制机制

认知无线网络中资源动态变化,必须制定特别的传输控制机制来协调各节点间的传输.该文提出一种新的反压式传输控制机制,充分利用局部节点间的调整能力,将端到端传输中出现的不良网络状况尽量解决在局部,使得源节点可以较温和地做出端到端控制,从而保证端到端传输的高效与平稳.大量仿真证明,该文控制机制能有效适应认知无线网络的动态环境,保证较高效且平稳的端到端传输.     

时间触发总线时间同步和端到端时延测试方法

分析了TTP总线时间同步机制和基于中断方式的端到端数据传输模式,以及节点间时间同步、端到端时延和抖动等参数,设计了同步精度和时延测试方法,构建测试原型系统和配置场景并开发测试用例。结果表明,各节点间的时间偏差小于总线配置场景所允许的同步精度上限5us,端到端时延263.30～267.43us。因时间槽设置为250us,可知主机应用层与总线控制器同步方式下数据传输的端到端时延主要取决于时间槽所占时间。此测试方法和所用的原型系统可用于TTP总线通信系统设计和部署的优化。     

对IPSec VPN进行运营管理的若干问题的研究

网络管理系统是IPSec(IP security,IP安全)VPN(virtual private network,虚拟专用网络)作为一种电信运营业务的关键组成部分.VPN节点设备部署在运营商网络的边缘,这种网络模式使得对节点的管理不同于对传统网络的管理,其中,VPN业务网络拓扑的自动发现和对私有网络中的设备进行管理是两个关键的问题.本文通过在网络管理系统中指定根节点,然后利用根节点中的SA(security association,安全联盟)信息来获得其他VPN节点的地址信息,从而实现VPN拓扑的自动发现;针对私有网络中的设备地址不可达的问题,本文提出了主动注册的技术,并利用主动注册同网络管理代理转发技术相结合的方法实现了对私有网络中设备的管理.     

基于C／S管理模式的统一网络管理系统——OpticalView

介绍自主研制开发的一套基于客户机／服务器(C／S)管理模式的统一网络管理系统——OpticalView,它不但实现了标准的SNMPv2网管接口．可对不同厂商设备实现统一的网络管理;而且还实现了端到端的业务配置和业务故障时自动的网络恢复功能。此外,由于采用Java语言作为开发平台,使系统能支持多种操作系统,实现了灵活跨平台的功能。     

Resource allocation in a dynamically partitionable bus networkusing a graph coloring algorithm

An efficient dynamic graph traversal algorithm is used to identify nonconflicting requests and to allocate network resources in a dynamically partitionable bus network (DPBN). In centralized network control a special processor receives from the control computer of a partitionable bus network an adjacency matrix which indicates conflicts among requests. It applies the dynamic graph traversal algorithm and returns the identified nonconflicting requests to the control computer. The control computer then physically partitions the network into a number of subnetworks for processing the nonconflicting requests in parallel. In distributed control, each station determines conflicts and sets the switches. The results of performance evaluation show a 40% decrease of network delay as compared with a fully utilized, but unpartitioned local area network     

GDSR：一种基于车载自组网的分组路由协议

针对DSR路由协议因节点频繁移动,路由发现和路由维护过程频繁发生,导致数据传输的时延增加和丢包率增加的问题.在DSR路由协议基础上,提出一种带有分组的DSR路由协议（GDSR）.该协议通过K-medoids聚类算法合理地选择组头,使得分组路由协议更加适合车载自组网的多变的拓扑结构.仿真结果表明,带有分组的GDSR路由协议能够降低数据传输的端到端的时延和丢包率.     

Delay Analysis of All-Optical Packet-Switching Ring and Bus Communications Networks

We study the delay performance of all-optical packet communication networks configured as ring and bus topologies employing cross-connect switches (or wavelength routers). Under a cross-connect network implementation, a packet experiences no (or minimal) internal queueing delays. Thus, the network can be implemented by high speed all-optical components. We further assume a packet-switched network operation, such as that using a slotted ring or bus access methods. In this case, a packet's delay is known before it is fed into the network. This can be used to determine if a packet must be dropped (when its end-to-end delay requirement is not met) at the time it accesses the network. It also leads to better utilization of network capacity resources. We also derive the delay performance for networks under a store-and-forward network operation. We show these implementations to yield very close average end-to-end packet queueing delay performance. We note that a cross-connect network operation can yield a somewhat higher queueing delay variance levels. However, the mean queueing delay for all traffic flows are the same for a cross-connect network operation (under equal nodal traffic loading), while that in a store-and-forward network increases as the path length increases. For a ring network loaded by a uniform traffic matrix, the queueing delay incurred by 90% of the packets in a cross-connect network may be lower than that experienced in a store-and-forward network. We also study a store-and-forward network operation under a nodal round robin (fair queueing) scheduling policy. We show the variance performance of the packet queueing delay for such a network to be close to that exhibited by a cross-connect (all-optical) network.     

Improved ant colony-based multi-constrained QoS energy-saving routing and throughput optimization in wireless Ad-hoc networks简

In order to establish a route supporting multi-constrained quality of service（QoS）, increase network throughput and reduce network energy consumption, an improved ant colony-based multi-constrained QoS energy-saving routing algorithm（IAMQER） is proposed. The ant colony algorithm, as one of the available heuristic algorithms, is used to find the optimal route from source node to destination node. The proposed IAMQER algorithm, which is based on the analysis of local node information such as node queue length, node forwarding number of data packets and node residual energy, balances the relationship between the network throughput and the energy consumption, thus improving the performance of network in multi-constrained QoS routing. Simulation results show that this IAMQER algorithm can find the QoS route that reduce average energy consumption and improves network packet delivery ratio under the end-to-end delay and packet loss ratio constraints.     

Security and performance enhancement of AODV routing protocol

A mobile ad hoc networks (MANET) is a decentralized, self‐organizing, infrastructure‐less network and adaptive gathering of independent mobile nodes. Because of the unique characteristics of MANET, the major issues to develop a routing protocol in MANET are the security aspect and the network performance. In this paper, we propose a new secure protocol called Trust Ad Hoc On‐demand Distance Vector (AODV) using trust mechanism. Communication packets are only sent to the trusted neighbor nodes. Trust calculation is based on the behaviors and activities information of each node. It is divided in to trust global (TG) and trust local (TL). TG is a trust calculation based on the total of received routing packets and the total of sending routing packets. TL is a comparison between total received packets and total forwarded packets by neighbor node from specific nodes. Nodes conclude the total trust level of its neighbors by accumulating the TL and TG values. The performance of Trust AODV is evaluated under denial of service/distributed denial of service (DOS/DDOS) attack using network simulator NS‐2. It is compared with the Trust Cross Layer Secure (TCLS) protocol. Simulation results show that the Trust AODV has a better performance than TCLS protocol in terms of end‐to‐end delay, packet delivery ratio, and overhead. Next, we improve the performance of Trust AODV using ant algorithm. The proposed protocol is called Trust AODV + Ant. The implementation of ant algorithm in the proposed secure protocol is by adding an ant agent to put the positive pheromone in the node if the node is trusted. Ant agent is represented as a routing packet. The pheromone value is saved in the routing table of the node. We modified the original routing table by adding the pheromone value field. The path communication is selected based on the pheromone concentration and the shortest path. Trust AODV + Ant is compared with simple ant routing algorithm (SARA), AODV, and Trust AODV under DOS/DDOS attacks in terms of performance. Simulation results show that the packet delivery ratio and throughput of the Trust AODV increase after using ant algorithm. However, in terms of end‐to‐end delay, there is no significant improvement. Copyright © 2014 John Wiley & Sons, Ltd.     

LSAPSP: Load distribution‐based slot allocation and path establishment using optimized substance particle selection in sensor networks

Sensor node energy conservation is the primary design parameters in wireless sensor networks (WSNs). Energy efficiency in sensor networks directly prolongs the network lifetime. In the process of route discovery, each node cooperates to forward the data to the base station using multi‐hop routing. But, the nodes nearer to the base station are loaded more than the other nodes that lead to network portioning, packet loss and delay as a result nodes may completely loss its energy during the routing process. To rectify these issues, path establishment considers optimized substance particle selection, load distribution, and an efficient slot allocation scheme for data transmission between the sensor nodes in this paper. The selection of forwarders and conscious multi‐hop path is selected based on the route cost value that is derived directly by taking energy, node degree and distance as crucial metrics. Load distribution based slot allocation method ensures the balance of data traffic and residual energy of the node in areal‐time environment. The proposed LSAPSP simulation results show that our algorithm not only can balance the real‐time environment load and increase the network lifetime but also meet the needs of packet loss and delay.     

一种新型的光分组交换环网体系结构

提出了一种以波长为标签的新型全光变长分组交换环网的体系结构、网络节点的光分组数据包收发模型,以及防止光分组冲突的多令牌协议。使用多令牌协议的环网在进行光分组交换时,不需要高速的光子器件,无需使用延迟线、电中继以及解决光分组的冲突问题。通过数值仿真,分析了4节点、8节点和16节点环网巾光分组各种的时延特性以及网络的吞吐量特性。结果表明,当网络负载增大时,数据包的平均时延增大,同时网络节点的吞吐量和资源利用率也随之增大;网络节点数目越多,网络的吞吐率也越大。     

认知无线网络中基于主用户行为的联合路由和信道分配算法

针对认知无线网络中主用户行为将导致频谱瞬时变化而影响路由稳定性的问题,提出了一种基于主用户行为的路由和信道联合分配算法。该算法通过采用呼叫模型对主用户行为建模,并根据动态源路由协议的路由寻找机制,在目的节点等待多个路由请求分组后选择受主用户行为影响最小的路由,然后沿着所选定路径的反方向传送路由回复分组并完成信道分配。理论分析证明了算法中的链路平均持续时间期望与主用户活动概率成反比且具有与网络节点数成正比的计算复杂度。仿真结果表明,该算法具有比Gymkhana路由方案更高的分组投递率和更低的平均分组时延。     

A distributed ant-based algorithm for routing and wavelength assignment in an optical burst switching flexible spectrum network with transmission impairments

This work describes a distributed algorithm inspired by ant colony optimisation for a solution to the problem of dynamic routing and wavelength assignment with wavelength continuity constraint in optical burst switched networks. The evaluation was conducted in a wavelength division multiplexed network environment with limited number of wavelength channels and in a flexible spectrum network environment undergoing transmission impairments. The simulations in the flexible spectrum network environment aim to replicate the effects of both linear and nonlinear physical layer impairments. Under these effects, an optical burst control packet could be lost during traversal of the network with no measure in place to notify the network of the loss or to free up optical resource reservations. The optical burst switching acknowledgement protocol has been modified in this work to account for a burst control packet failure by implementing a traversal acknowledgement to cater for its loss. The performance of the distributed ant-based algorithm has been extensively evaluated on several network topologies and compared with that obtained by shortest path routing and ant colony routing and wavelength assignment. The results show that the distributed ant-based algorithm significantly improves the burst transmission success probability in the wavelength division multiplexed network environment and provides a good solution in the flexible spectrum network environment undergoing transmission impairments.     

Network queue scheduling algorithm based on self-similar traffic level grading prediction

Self-similarity characteristic of network traffic will lead to the continuous burstness of data in the network.In order to effectively reduce the queue delay and packet loss rate caused by network traffic burst,improve the transmission capacity of different priority services,and guarantee the service quality requirements,a queue scheduling algorithm P-DWRR based on the self-similarity of network traffic was proposed.A dynamic weight allocation method and a service quantum update method based on the self-similar traffic level grading prediction results were designed,and the service order of the queue according was determined to the service priority and queue waiting time,so as to reduce the queuing delay and packet loss rate.The simulation results show that the P-DWRR algorithm can reduce the queueing delay,delay jitter and packet loss rate on the basis of satisfying the different service priority requirements of the network,and its performance is better than that of DWRR and VDWRR.