基于IP over WDM的光城域网

提出了基于IP over WDM的光城域网方案,详细阐述了波长选路WDM光城域网的多级网络拓扑及波长配置方式,并分析了波长配置方式对波长选路由策略的影响。     

未来城域网中的光包交换技术

光交换是全光网络的核心技术。由于全光包交换将极大地提高网络交换和路由分配的灵活性、增加交换用户的数量、实现网络节点的自动识别等功能，使得全光包交换成为下一代城域网技术的有力竞争者。本文详细讨论了全光包交换技术，具体包括包的结构、节点结构、应用于城域网中的接口和路由问题、包的同步与碰撞问题、包交换技术发展的现状以及在实现过程中仍存在的技术问题等。     

Ad-hoc网络的关键技术——MAC层协议研究

介绍了无线Ad-hoc网络MAC层协议面临的问题，重点分析了隐蔽终端问题和暴露终端问题产生的原因以及解决这些问题相应的策略。在此基础上提出了一种结合了定向天线、RTS／C3S握手和信道分割的新的MAC协议。     

全光包交换技术原理及其应用

全光包交换技术对带宽的利用率很高，其特有的优点（高容量、灵活性、高透明性及可伸缩性等）将会给下一代全光网络带来广阔的应用前景。文中讨论了光包交换的包结构、节点结构和网络结构，以及实现包交换的关键技术，最后就全光包交换技术在下一代城域网中的应用作了论述。     

波分复用技术在城域网中应用探讨

本文首先简要介绍了WDM的发展和特点，以及城域网的业务特点和传输要求。针对城域网的特性要求介绍了适于城域组网的CWDM技术，并对未来城域WDM技术发展进行展望。     

DWDM技术在城域网中的应用

介绍了城域网中引入DWDM技术的必要性，以及DWDM技术的应用和发展趋势。     

WDM应用于城域网

波分复用(WDM)技术的出现使得光传输网络的容量有了上百倍的增长。但早期的WDM光传输系统只应用于长途话音和数据传输,在接入网和城域网中应用较少。目前的城域网基础设施主要由专门为话音传输而设计的SONET/SDH设备所组成,很难适应快速发展的用户需求,从而成了通信网络上的瓶颈,限制了宽带业务的快速发展。WDM在长途网的成功应用使得不少运营商把目光投向将WDM应用于城域网的建设。1.WDM技术的优势在新一代的网络中,WDM技术将在超大容量、高度灵活、安全可靠的宽带信息网络建设中扮演极为重要的角色。WDM技术为运营商提供了源…     

城域WDM技术及展望

由于路由业务不可预计,因此城域以太网不支持对时延很敏感的业务(语音/图像等)。由于IP的WAN(广域网)接口非常昂贵,若采用IP光接口直接互联组成星型网络结构,不但造价高,而且也无法支持有效的保护(即保护倒换时间<50ms),从而不能很好地提供电信级服务。     

新一代超高速光纤通信--光波分复用WDM系统

简要介绍光波分复用系统的基本原理、结构组成、功能配置、关键技术部件和技术特点，说明光波分复用WDM系统是今后光通信发展的方向。     

WDM光传输系统2.5Gbit／s光发送模块研究

本文介绍了作者设计，调试的２．５Ｇｂｉｔ／ｓ光发送模块的工作原理、关键技术、典型性能参数，该模块通过控制激光器温度来稳定其中心波长，为波分复用系统的应用提供了具备稳定中心波长特性的光源。     

A MAC Protocol for IP Differentiated Services in a WDM Metropolitan Area Network

This paper presents a Media Access Control (MAC) protocol for a WDM passive optical star. The protocol supports scalable service differentiation for Internet traffic in the spirit of the IETF's Diffserv architecture. We describe the functional elements of the protocol (signaling, arbitration, service disciplines and buffer management techniques) and the way they interact to support the Diffserv's Expedited Forwarding (EF) PHB and Assured Forwarding (AF) PHB group, where PHB stands for Per-Hop-Behavior. Extensive simulation results give quantitative estimations of the performance of the protocol under combined EF/AF traffic.     

基于WDM技术的宽带无源光网络

为了进一步满足接入网增加带宽的需求,同时考虑到WDM器件的局限性,提出了一种基于WDM与现行的功率分束无源光网络（PS－PON）技术的新型光纤接入网络结构,并设计了IP数据报在PON中传送具体优化实施方案。     

Performance evaluation of CSMA/ID MAC protocol for IP over WDM ring networks

In this paper, a packet pre‐classification media access control protocol based on a carrier sense multiple access with idle detection (CSMA/ID) scheme is investigated for supporting IP packets over all‐optical WDM ring networks. The purpose of the protocol is to increase throughput and to decrease the packet transmission delay of IP packets over optical networks in a metropolitan area network. This protocol avoids both packet collision and packet fragmentation. In order to improve the utilization of the network, the packets transmitted from a local area network are first pre‐classified into various class queues of an access point (AP) according to their length. After checking the available space based on the wavelength received by the receivers of the AP, the packets in the queues are transmitted. An analytical model is developed to evaluate the performance of the protocol, with simulation results showing good network efficiency. The proposed network has short‐term variations that introduce unfairness conditions. This problem could be overcome by assigning a quota on individual queues to allow all queues fair access. Copyright © 2008 John Wiley & Sons, Ltd.     

城域波分组网的若干关键因素考虑

在结合技术原理与实际经验的基础上,基于城域波分技术的特点,论述了城域波分组网设计时的功能和性能要求,重点探讨了保护方式、OSNR指标、功率和色散预算等方面的技术要求。     

Fair MAC protocol for optical ring network of wavelength-shared access nodes

In this paper, a WDM optical ring consisting of access nodes with fixed transmitter-n fixed receivers (FT—FR ⁿ ) is considered. As access nodes share a wavelength channel there is trade-off between node throughput and fairness among them. In order to abbreviate the transmission unfairness and to increase the throughput, we propose p-persistent medium access control (MAC) protocol. Each node uses the carrier sense multiple access with collision avoidance (CSMA/CA) protocol to transmit packets, and decides whether to use a local empty slot with probability p when a transferred packet based on source-stripping is dropped and emptied. Numerical prediction for the proposed MAC protocol is introduced to compute the maximum node throughput under uniform traffic condition. For more detail results, we use network simulation with self-similar traffic and introduce various results. The proposed MAC protocol gives better node throughput than non-persistent protocol and shows an improved fairness factor than 1-persistent protocol. Through simulation, we also find the reasonable probability of p-persistent protocol for a given architecture.     

基于令牌的无线传感器网络MAC协议

为了更进一步减少信道冲突和网络能耗,提出一种基于令牌的链式无线传感器网络MAC协议.协议自定义信标帧和数据帧,在传感器节点完成时间同步后,以信标帧中的令牌为控制信息对相邻两个传感器节点进行收发控制,实现数据从链尾节点到链头节点的顺序上传.研究表明,该协议不仅能够满足系统的稳定性要求而且能够有效降低功耗.     

基于网络编码与空时编码的协作MAC协议

针对无线ad hoc网络中协作造成的中继效率低以及不同QoS需求难以满足等问题,提出了一种联合网络编码和空时编码的协作MAC协议(NSTCMAC)。NSTCMAC将网络编码与空时编码技术相结合,设计出区分业务类型的协作MAC协议传输机制,以满足不同业务类型的QoS需求;进一步通过马尔科夫链模型分析了区分业务类型的协作机制及性能。仿真结果表明,相比传统的DCF、COOPMAC以及CD-MAC协议,NSTCMAC协议能更好地保证不同的QoS需求,并能有效地解决协作造成的中继效率低的问题。     

Dynamic survivable mapping through reconfiguration in IP over WDM network

A new approach for network survivability problem in Intemet protocol （IP） over wavelength division multiplexing （WDM） optical network is proposed to enhance the IP layer restorability under physical link failure through logical topology reconfiguration. More specifically, after traffic arrival and departure, reconfiguring the logical topology correspondingly is helpful to minimize the traffic disruption after physical link failure. So, in this paper, this problem is proposed for first time and formulated as an integer linear programming （ILP） problem. And then, two heuristic algorithms are proposed. The performance of proposed algorithms have been evaluated through simulations, and the results show that reconfiguring the logical topology dynamically could achieve more than 20% improvement of the restorability of traffic in IP layer, but with acceptable resource cost.