柳州电信cdma2000网络室分小区PN优化研究

近年来,中国电信在原中国联通CDMA网络基础上进行了大规模的网络升级和扩容,将CDMA 1x网络升级至cdma2000。在覆盖建设已基本完成的情况下,用户集中区域的室分网络建设和优化逐渐成为CDMA网络发展重点。其中,PN规划对cdma2000网络质量影响重大,是cdma2000网络优化中必不可少的一部分。本文基于以上背景,结合柳州cdma2000网络现状,分析和研究了现有cdma2000网络室分小区PN方案中PN资源紧张、同PN-Offset和邻PN-Offset干扰等问题,提出了一种PN规划优化方案,以减弱网络信号干扰、提高通信质量、打造高品质3G网络。     

Klonet:面向技术创新的网络模拟实验平台

网络关键技术的创新是推动网络未来发展和整个行业进步的使能条件,为此亟须一个能对创新技术进行方便、快捷验证的网络实验平台,以有效降低创新门槛、促进创新趋势。通过分析网络模拟技术在网络实验中的优势,结合网络技术创新对网络实验平台的需求,提出了面向技术创新的网络模拟实验平台Klonet。该平台可以灵活地扩展规模、全方位地对实验网络进行模拟、细粒度地管理模拟网络,并促进实验的工作流程。结合两个具体的用例,分析了在Klonet上进行实验的方法,验证了Klonet支持网络技术创新的能力。     

The design policy for a GSM-based IMT-2000 network

The third-generation mobile network has been a topic of considerable interest worldwide and has begun to be commercialized throughout the world. The 3G mobile network has evolved from two types of 2G networks; one type has evolved from GSM and another from ANSI-41. We operate the Personal Digital Cellular network as a 2G network and have designed a GSM-based IMT-2000 network as a 3G network. This article gives our design policy for the GSM-based IMT-2000 network and the technology that enabled us to develop the network based on this policy (e.g., ATM switching in the core network). Furthermore, the foundations for 2G/3G dual network operation (e.g., number portability and succession of 2G services in a 3G network) and efficient transition from a 2G network to a 3G network are also considered.     

Development of Trusted Network and Challenges It Faces

As the information network plays a more and more important role globally, the traditional network theories and technologies, especially those related to network security, can no longer meet the network development requirements. Offering the system with secure and trusted services has become a new focus in network research. This paper first discusses the meaning of and aspects involved in the trusted network. According to this paper, the trusted network should be a network where the network’s and users’ behaviors and their results are always predicted and manageable. The trustworthiness of a network mainly involves three aspects: service provider, information transmission and terminal user. This paper also analyzes the trusted network in terms of trusted model for network/user behaviors, architecture of trusted network, service survivability and network manageability, which is designed to give ideas on solving the problems that may be faced in developing the trusted network.     

IP核心网的BGP增量规划

BGP协议的研究是目前IP核心网中的一个研究热点,对IP核心网的规划有重要意义.随着网络通信业务的广泛应用,越来越多的通信网络无法满足日益增长的业务需求.除了不断建设新的网络,还需要对旧网络进行改造.而对IP核心网的增量规划的研究对于旧网络向IP核心网的改造具有重要的指导作用.本文首先分析了IP核心网的上BGP协议的组...     

Learning with handoff cost constraint for network selection in heterogeneous wireless networks

In heterogeneous wireless networks, network selection algorithms provide the user with the optimum network access choice. The optimal network is evaluated according to network parameters. Considering that the network parameters are dynamic and unavailable for the user in realistic heterogeneous wireless network environments, most existing network selection algorithms cannot work effectively. Learning‐based algorithms can address the problem of uncertain network parameters, while they commonly need considerable network handoff, resulting in unbearable handoff cost. In order to tackle the uncertainty of network parameters, we formulate the network selection problem as a multi‐armed bandit problem. Moreover, two online learning‐based network selection algorithms with a special consideration on reducing network handoff cost are proposed. By updating in a block manner, both algorithms achieve optimal logarithmic‐order regret and limited network handoff cost. The simulation indicates that the two algorithms can significantly reduce the network handoff cost and improve the transmission performance compared with existing algorithms, simultaneously. Copyright © 2014 John Wiley & Sons, Ltd.     

基于SDN技术的校园网虚拟网络业务流程实现方案

随着信息技术的快速发展,校园网在现代教育和科研中起着越来越重要的作用。SDN技术作为一种新型的网络架构和管理技术,可以对校园网进行优化和管理,提高网络的灵活性、可靠性和安全性。文中主要介绍了基于SDN技术的校园网虚拟网络业务流程的实现方案,具体包括SDN技术概述、校园网虚拟网络技术概述、SDN技术在校园网虚拟网络中的应用、校园网虚拟网络业务流程设计等。     

一种适用于Ad Hoc K重组播网络的负载均衡路由算法

Ad Hoc网络是一个多跳的无基础设施网络,本文在分析Ad Hoc网络自身特点的基础上,引入了一种多组播业务并存的K重组播网络,这种网络相对传统的组播网络具有节省系统开销,降低能量消耗的优点.文中对K重组播网络中的节点连接度的不同变化情况进行了理论上的详细研究,并在此基础上设计了一种适用于K重组播网络的负载均衡路由算法.仿真结果表明该路由算法拥塞控制性能良好,并能显著提高组播业务的稳定性.本文提出的这种K重组播网络能够广泛的应用于许多实际通信场合.     

无线传感器网络规模可扩展性的实现算法

无线传感器网络是由许多分布的智能传感器节点组成的多跳无线网络.针对无线传感器网络的特点,在能量有效的传感器网络MAC协议下,提出并实现了网络自适应规模扩展的算法.并利用网络仿真工具NS-2(network simulator 2.27版)实现仿真.该算法在无线传感器网络MAC层实现了网络规模的可扩展性,增强了网络自适应网络规模变化的能力.     

面向SDN网络虚拟化平台的控制器放置算法

随着网络技术发展,以网络虚拟化为手段解决TCP/IP网络体系结构僵化问题已成为未来网络领域发展的主流方向之一.SDN(software defined networking,软件定义网络)作为一种新兴的网络体系结构,为网络虚拟化提供了有效的解决方案.首先总结了当前具有代表性的SDN网络虚拟化平台,并对比了SDN与传统网络环境中部署虚拟网的区别,然后针对SDN网络虚拟化平台中的虚拟网络映射问题,提出一种时延敏感的虚拟化控制器放置算法,最后通过实验验证了该算法在提高网络资源的利用效率的同时,保证了控制器与底层交换机的通信时延在可接受范围之内.     

大型IP网络时延的主成分分析

网络时延是评估网络性能的关键指标之一。主成分分析(PCA)是数据挖掘领域常用的一种多变量分析和降维算法。通过对大型IP网络时延进行PCA分析,旨在挖掘网络时延的深层原因及网络各节点间的相互依赖关系,并搭建一个科学合理的网络时延评价体系,最终得到IP网络建设、优化改造的有效建议。对历史网络时延进行离线分析只是主成分分析方法的一种初步应用,今后可结合网络拓扑结构、现网流量流向、路由、距离等相关因素,将主成分分析方法应用到针对网络流量、网络时延、网络丢包等网络性能的实时在线监测分析中,进一步提升网络运营的效率和质量。     

基于CC2430的无线传感器网络的实现

无线传感器网络是一项新兴的技术,具有广泛的应用领域。在简单介绍无线传感器网络的概念及其特点的基础上,着重讨论基于ZigBee技术和433 MHz无线射频技术的无线传感器网络的实现方法,包括无线传感器网络的硬件和软件设计。ZigBee是一种具有全球统一标准的自组织网状网,网络容量大、组网灵活。多个ZigBee网络的协调器节点通过433 MHz无线射频组成星型网,有效地扩大了传感器网络的地理覆盖范围。实验结果表明,网络节点及整体网络均获得了良好的性能,验证ZigBee是实现无线传感器网络的理想解决方案。     

A strictly nonblocking network based on nonblocking 4×4 optical switches

Recently, the demand for communication has been growing rapidly. Hence, optical multistage network technologies are more appreciated nowadays. A double-layer network is a strictly nonblocking network, and it has the lowest system insertion loss of non-dilated networks. A Beneš network is a rearrangeably nonblocking network, and it has the same system insertion loss as a double-layer network. We have proposed the use of modified polarization selection elements (PSEs). The system insertion loss, number of drivers, and number of required components of a double-layer network could be reduced if it is constructed with modified PSEs. A nonblocking 4×4 optical switch with two stages of polarization selective elements has been presented in our previous study. Based on this nonblocking 4×4 optical switch, we propose a strictly nonblocking network structure which features even lower system insertion loss than those of a double-layer network and a Beneš network. The signal-to-noise ratio of the proposed network structure is a constant, and is higher than the constraint, although it is lower than that of the double-layer network. The number of major components of the proposed network is less than that of a double-layer network and larger than that of a Beneš network, since a Beneš network is rearrangeably nonblocking. We also offer a routing algorithm for the new proposed network; the time complexity of the routing algorithm is O(1).     

校园网常见故障的快速定位及解决方案

随着计算机网络技术的飞速发展，每所大学都建立了具有自己特色的校园网。校园网能满足学校师生网络办公、网上教学、资料共享、电子阅览等多种现代化办公、教学的需求。然而，校园网在带来诸多便利的同时，也逐渐复杂和庞大，网络故障问题越来越隐蔽和频发。在出现网络故障时，需要准确地查找、定位故障源，快速解决网络故障，恢复正常的工作和教学秩序。文中对校园网中常见的网络故障进行了分析，并介绍了解决方法和预防措施，以期为相关人员提供参考。     

基于暗网的蠕虫早期检测技术在专用网络中的应用

为了对网络蠕虫等网络攻击行为进行早期检测,文章设计实现了一个基于暗网的可视化的早期检测系统,并采用原型设计和实际网络实验的方法,在某专用网络中进行了对比实验,结果表明该系统在专用网络中比传统入侵检测系统更早发现蠕虫等网络攻击,且时间提前量十分可观,说明基于暗网的早期检测技术在与国际互联网隔离的专用网络中有着良好的应用前景。     

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.     

智能光网络中的自感知技术

现有的光网络虽然已经能够提供充足的传输容量,但其智能性仍然处于非常初级的阶段,远远不能满足具有随机性和突发性IP业务对承载网络的需求。光网络的自感知技术是实现真正意义上的智能化自组织光网络的首要条件。自组织光网络作为各种业务的承载网络,不仅需要实时监测和动态感知光链路物理参数、光信号质量、光网络拓扑及链路负载等光网络自身特性,还需要感知所承载业务的属性及其对光网络的传送需求（延时、抖动、丢包率等）,为实现动态高效灵活的。即插即用”自组织光网络提供充足的信息。     

未来网络的研究现状与发展前景

扼要阐述未来网络的研究意义,介绍未来网络的发展历程,全面分析未来网络在多媒体网络、网址分配、网络计算、数据中心、网络安全及故障诊断等相关领域的研究现状,并在此基础上预测未来网络在网络规模、开放开源、传输速度等方面的发展前景。最后指出在未来网络发展过程中应当注意的网络安全、网络节能及商业模型构建等问题。     

未来通信网络架构及演进方案

随着互联网的飞速发展,网络承载内容逐渐由以基于连接的信息交互为主的业务,转变为以内容分享为主（视频）的业务,网络传送大量冗余信息,造成非正常的大规模投资,且业务质量难以保障,迫切需要研究构建与业务发展匹配的网络。通过对内容分享连接关系和通信网络架构连接关系的研究,探究二维差时分发或三维分发等实现方式,改造CDN构建内容边缘节点,优化调整核心网、无线网、承载网架构和网元部署,并考虑引入卫星等天基网络,从而在现有通信网络上构建无标度小跳数网络,实现网络架构与内容分发的匹配。     

一种基于暗网的蠕虫早期检测方法

为了对网络蠕虫等网络攻击行为进行早期检测,论文设计实现了一个基于暗网的可视化的早期检测系统,并采用实际网络实验的方法,在某专用网络中进行实验,结果表明该系统在专用网络中比传统入侵检测系统更早发现蠕虫,且时间提前量十分可观。