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基于千兆以太网的无源光网络系统及其实现技术 总被引:1,自引:0,他引:1
以太网无源光网络EPON是目前光纤到户宽带接入的主流方式.时延补偿、动态带宽分配以及局端桥接等是构建EPON系统的关键技术.为了避免多个ONU发送冲突,实现用户端设备的时延补偿和自动加入,本文采用绝对时标来补偿不同光网络单元(ONU)往返时间的差异,完成其往返时间的计算和动态测距.上行链路动态带宽分配则采用基于逻辑链路标识(LLID)的流量统计算法,结合其服务水平协议(SLA),获得了较低的延时特性和很高的带宽利用率.在EPON光线路终端(OLT)中借助动态过滤数据库技术实现了一个OLT和多个ONU的逻辑链路MAC仿真,解决了EPON和常规以太网IAN的兼容性问题.这些技术方案在武汉邮电科学研究院(WRI)完成的863科技攻关项目中均进行了严格的测试,结果符合预期要求.提供的现场测试数据表明研制的样机系统能很好支持多种业务的综合接入. 相似文献
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消费者对运营商的选择促使运营商开始对其服务质量进行承诺,导致了服务等级协议(SLA)的产生和发展.在建设新的业务支撑系统时,需要按照SLA管理的思路,在用户业务层、用户网络层、运营商内部业务层、运营商网络层和运营商的其它运营、维护和支撑系统之间建立SLA管理系统.在对已经部署的网管进行改造提供SLA支撑时,需要从服务性能数据收集和分析以及服务故障后服务恢复时间的度量两个方面着手进行. 相似文献
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EPON(Ethernet Passive Optical Networks)系统中有两个问题:一是EPON中最关键成分之一--动态带宽分配;二是EPON的上行(ONU到OLT)为多点到点的传输,不能与以太网标准设备兼容.结合这两个问题介绍一种优化的带宽分配方案,它由基于参数的访问权限控制(CAC)机制、平均分配算法(EDA)和带宽预留轮询算法(BGP)组成,并将算法信息加入EPON内部帧,根据网络用户的服务等级(SLA)分配带宽,为EPON与以太网标准设备兼容提供算法支持,优化EPON网络的性能. 相似文献
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消费者对运营商的选择促使运营商开始对其服务质量进行承诺,导致了服务等级协议(SLA)的产生和发展。在建设新的业务支撑系统时,需要按照SLA管理的思路,在用户业务层、用户网络层、运营商内部业务层、运营商网络层和运营商的其它运营、维护和支撑系统之间建立SLA管理系统。在对已经部署的网管进行改造提供SLA支撑时,需要从服务性能数据收集和分析以及服务故障后服务恢复时间的度量两个方面着手进行。 相似文献
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EPON(以太无源光网络)技术已经在我国三大运营商大规模商用,EPON点对多点的拓扑特点及上行时分多址复用方式,对其网络运行维护提出了巨大挑战。文章结合EPON光网络测试的特点,提出一种基于协议分析的EPON光网络测试系统设计方案。该方案设计一种新型的物理接入方式用以实现测试系统的在线测试,同时通过对EPON协议帧的分析、比对可快速得出测试结论,定位故障节点。 相似文献
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消费者对运营商的选择促使运营商开始对其服务质量进行承诺,导致了服务等级协议(SLA)的产生和发展。在建设新的业务支撑系统时,需要按照SLA管理的思路,在用户业务层、用户网络层、运营商内部业务层、运营商网络层和运营商的其它运营、维护和支撑系统之间建立SLA管理系统。在对已经部署的网管进行改造提供SLA支撑时,需要从服务性能数据收集和分析以及服务故障后服务恢复时间的度量两个方面着手进行。 相似文献
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The passive optical network (PON) technology has been drastically improved in recent years. In spite of using the optical technology, the utilization of the entire bandwidth is a very challenging task. The main categories of PON are the Ethernet passive optical network (EPON) and gigabit passive optical network (GPON). These two networks use the dynamic bandwidth allocation (DBA) algorithm to attain the maximum usage of bandwidth, which is provided in the network dynamically according to the need of the customers with the support of the service level agreement (SLA). This paper will provide a clear review about the DBA algorithm of both technologies as well as the comparison. 相似文献
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波分复用技术结合时分复用形成了混合WDM EPON,如何提高系统的带宽利用率和用户服务质量成为关键技术。结合已有算法的优缺点,提出一种新的动态波长带宽分配算法。该算法结合业务等级分类和用户服务等级协议的权重为光网络单元分配相应的带宽和波长,以达到提高服务质量、带宽分配公平性,提高上行带宽利用率和改善网络性能的目的。 相似文献
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一种支持多用户SLA的EPON上行带宽分配算法设计 总被引:6,自引:0,他引:6
在接入网服务等级协定的基础上,分析了以IPACT和CyclicDBA为代表的EPON上行动态带宽分配算法,讨论了其对EPON上多用户SLA支持所存在的固有缺陷。提出了适合SLA应用的EPON控制帧结构:授权帧和请求帧。根据这两种控制帧,设计了一种新型的支持多用户SLA的EPON上行信道带宽分配算法,等级轮询固定周期算法。通过理论分析和计算机仿真测试表明该算法针对EPON不同类型的接入用户均达到了较理想的性能指标,高优先级业务良好的时延和时延抖动特性,各种业务队列的尺度平稳,同时HPFCT还解决了传统轮询算法中低负载时下行带宽浪费明显的问题。 相似文献
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Hongseok Kim Sangtae Ha Mung Chiang Dae Kyung Kang Jin Hee Kim 《Photonic Network Communications》2012,24(2):138-150
In this paper, we propose a new dynamic bandwidth allocation technique, SLIding Cycle Time (SLICT) for TDM-PON, specifically focused on ethernet passive optical network (EPON). Based on the sliding cycle time constraint, the proposed algorithm guarantees the maximum polling interval, an essential property for delay-sensitive applications and interactive services. We then introduce an iterative resource pooling that processes bursty best-effort traffic and achieves high throughput even under non-uniform upstream traffic distribution. We prove that greedy iterative resource pooling converges to equal resource allocation exponentially fast. Extensive numerical simulations show that SLICT outperforms existing techniques in all aspects: throughput, delay, packet loss and average queue size. Finally, SLICT has been implemented on an EPON FPGA board and the performance is confirmed under real traffic. 相似文献
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Partha Bhaumik Saigopal Thota Kira Zhangli Jim Chen Hesham ElBakoury Liming Fang Biswanath Mukherjee 《Photonic Network Communications》2014,28(2):178-189
We present different mechanisms for downstream transmissions in the coax segment of Ethernet Passive Optical Network (EPON) Protocol over Coax (EPoC). EPoC is the transparent extension of EPON over a cable operator’s Hybrid Fiber-Coax network. For managing and controlling such a hybrid network, a network operator prefers to have a unified scheduling, management, and quality of service environment that includes both the optical and coax portions of the network. In EPoC, this is achieved by extending the EPON Medium Access Control to run over the coax physical layer, to have a centralized end-to-end network control from the cable head-end to the end users premises. In this paper, we focus on the downstream transmissions in EPoC. We study three different framing approaches for downstream coax frames based on how sub-carriers in an orthogonal frequency division multiplexed symbol are modulated. We discuss the merits and demerits of each approach and then compare them based on their control overheads and the maximum average data transmission rates each of them can achieve. We analyze how different parameters such as modulation profile, symbol duration, number of sub-carriers and length of resource blocks affect the data rates and the performance of downstream transmissions. We present simulation results to examine the implications of these factors on packet-level performance, such as delay. The results indicate that dynamic and hybrid framing approaches tend to perform better than static approaches, when traffic and usage pattern are identical to those in real-world scenarios. Finally, we outline the important engineering and research problems in this area which can be topics of future research. 相似文献
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As one of the most promising next-generation access network techniques, the user-oriented Ethemet passive optical network (EPON) should pay more attention to its quality of service (QoS). However, now the EPON adopts mostly differentiated services model (Diffserv) that only provides quality control on traffic aggregation, whereas, the quality of user session cannot be guaranteed when the network is overloaded with substantial connections. This article proposes to apply integrated services model (lntserv) in Diffserv-based EPON, which uses per-flow processing to guarantee QoS. In the simulation, a framework of combined Diffserv and lntserv model is employed in an EPON system, with a dynamic bandwidth allocation algorithm that adapts to it. The simulation results demonstrate that the EPON system with the combined models can provide more flexible, various control for user-oriented service quality. 相似文献
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A generalized protection framework using a new link-State availability model for reliable optical networks 总被引:1,自引:0,他引:1
Yurong Huang Wushao Wen Heritage J.P. Mukherjee B. 《Lightwave Technology, Journal of》2004,22(11):2536-2547
This paper investigates a generalized protection framework for availability-guaranteed connection provisioning in an optical wavelength-division-multiplexed (WDM) network. Reliability is a crucial concern in high-speed optical networks. A service level agreement (SLA), which mandates high service availability even in the face of network failures must be met in provisioning a reliable connection. In this study, a new link-state-modeling mechanism is developed to form a dynamic link-state parameter called link and resource availability (LRA), which represents physical-layer availability and resource status for an optical link. Such up-to-date link-state information can be used by a standard link-state routing protocol to efficiently provision reliable connections. Based on the link-state availability model, LRA, a connection-provisioning algorithm is then proposed which can guarantee customers' availability requirements. A new generalized protection model is developed through dynamic LRA-based provisioning. Numerical results demonstrate the performance of the proposed provisioning approach to be promising. 相似文献