基于QoS的EPON系统动态带宽分配机制

通过阐述以太网无源光网络（EPON）系统信道传输数据方式以及动态带宽分配的工作原理,进一步研究了动态带宽分配算法（DBA）在EPON系统中的应用。提出一种基于服务质量（QoS）的EPON系统动态带宽分配机制,该机制根据不同业务的优先级和动态带宽分配算法,灵活地分配上行带宽,提高了带宽利用率,改善了服务质量。     

EPON关键技术及其展望

无源光网络接入技术由于其支持高带宽和长距离等特性,将成为解决最后一公里问题的最佳方案.文章对以太无源光网络(EPON)的ONU自动发现、ONU测距、动态带宽分配等关键技术进行了分析和研究,最后对其技术发展方向10G EPON以及WDM-PON进行了展望.     

三种无源光网络的关键技术分析

介绍无源光网络的系统结构,分别从突发信号同步,测距以及带宽分配三个方面对基于ATM的PON（APON）,以太网PON（EPON）和GPON三种无源光网络进行分析。     

EPON加密系统的设计和实现

基于以太网的无源光网络（EPON）是一个点到多点的光接入网,由于其成本低、网络结构简单、高带宽等特点,被普遍认为是下一代宽带光接入网技术的最好选择。文中通过对EPON原理与技术的研究,分析了EPON系统的安全隐患,并结合EPON特点,提出了集成式EPON加密系统的设计和实现思路,并从原理、优劣势等方面进行了论述。     

博通推出业界首款10G EPON芯片

Broadcom（下称＂博通＂）公司宣布,正式推出业界首款10Gb以太网无源光网络（EPON）光网络单元（ONU）单芯片系统（SoC）解决方案.Broadcom的10GbpsBCM55030单芯片系统解决方案提供的带宽是现有1GEPON解决方案的10倍。非常适用于4G／LTE移动回传,既支持QoS有保证的带宽,也支持时序分配。     

基于千兆以太网的无源光网络系统及其实现技术

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．     

EPON中保证QoS的高效动态带宽分配算法

由于EPON系统上行链路多个ONU共享带宽的拓扑结构,系统的上行带宽分配算法一直是EPON系统讨论的热点。本文分析了现有带宽分配的算法,基于网络流量的自相似特性,提出了一种新的固定周期的轮询动态带宽分配算法。本算法不仅保证了上行带宽的高效利用率,同时保证了不同业务的QOS。为了验证算法的性能,本文给出了基于本算法的系统仿真结构和相关结果。     

EPON上行带宽动态分配算法的研究

讨论和分析了实现EPON系统的关键技术之一上行信道的复用技术,并针对EPON多点到点的拓扑结构特点介绍了一种动态的带宽分配方案。     

基于固定长度的EPON帧结构和MAC协议设计

以太无源光网络(EPON)已成为国内外接入网技术的最新研究热点,而EPON标准正在制定。针对EPON系统的核心关键技术之一的上行信道带宽动态分配问题,参照APON的G.983建议,提出了一种基于固定长度的EPON上下行传输帧结构和媒质接入控制(MAC)协议。该方案以APON为借鉴,将EPON中以太网帧长度固定下来;考虑到实时业务对时延敏感,MAC协议对实时业务实行优先带宽分配,对其他类型业务则采用动态带宽分配方案。最后通过建模防真分析了协议的信元时延(CD)特性。     

一种基于固定长度的EPON动态带宽分配方案

文中介绍了以太无源光网络(EPON),在此基础上提出了EPON的上下行帧结构,以及基于固定长度的一种EPON动态带宽分配方案。该方案以APON为借鉴,将EPON中以太网帧长度固定下来,采用对业务分时延优先级的动态分配算法。并对此方案的性能进行了分析。     

在工业网中EPON的DBA算法研究

EPON系统中,上行数据传输的动态带宽分配（DBA）算法是关键技术之一。针对EPON在工业网络通信中的应用,对现有的DBA算法进行了分析和改进,以保证监控和报警等特殊业务的实时送达,消除交叉轮询的带宽浪费,并对该算法进行了仿真实验。仿真结果表明,该算法的带宽利用率高,业务时延抖动低,并且在低负载时无轻载惩罚现象。     

EPON和WiMAX融合架构下带宽分配和调度机制的研究

以太网无源光网络(EPON)和IEEE 802.16(WiMAX)的融合网络在固定移动混合接入网中被认为是很有前景的接入方式.文中提出了3种WiMAX无线网络与EPON网络系统融合架构,融合系统同时具有光网络的高带宽和无线网络的灵活性.为了在接入网中支持QoS,本文为融合结构提出了一种动态带宽分配算法(DBA)和调度机...     

A survey of dynamic bandwidth allocation algorithms for Ethernet Passive Optical Networks

Ethernet Passive Optical Network (EPON) has been widely considered as a promising technology for implementing the FTTx solutions to the “last mile” bandwidth bottleneck problem. Bandwidth allocation is one of the critical issues in the design of EPON systems. In an EPON system, multiple optical network units (ONUs) share a common upstream channel for data transmission. To efficiently utilize the limited bandwidth of the upstream channel, an EPON system must dynamically allocate the upstream bandwidth among multiple ONUs based on the instantaneous bandwidth demands and quality of service requirements of end users. This paper introduces the fundamental concepts on EPONs, discusses the major issues related to bandwidth allocation in EPON systems, and presents a survey of the state-of-the-art dynamic bandwidth allocation (DBA) algorithms for EPONs.     

PON业务常见故障的处理

无源光网络(PON,Passive Optical Network)采用无源光分/合路器或光耦合器分配/汇聚各光网络单元(ONU,Optical Network Unit)信号的光接入网。PON系统系由光线路终端(OLT,Optical Line Terminal)、光分配网(ODN,Optical Distribution Network)、光网络单元(ONU)组成的信号传输系统,简称PON系统。目前主流PON综合接入系统根据采用的技术分为以太网无源光网络(EPON,Ethernet Passive Optical Network)和吉比特无源光网络(GPON,Gigabit-capable Passive Optical Networks)。     

Convergence of ethernet PON and IEEE 802.16 broadband access networks and its QoS-aware dynamic bandwidth allocation scheme

IEEE 802.16 and Ethernet Passive Optical Network (EPON) are two promising broadband access technologies for high-capacity wireless access networks and wired access networks, respectively. They each can be deployed to facilitate connection between the end users and the Internet but each of them suffers from some drawbacks if operating separately. To combine the bandwidth advantage of optical networks with the mobility feature of wireless communications, we propose a convergence of EPON and 802.16 networks in this paper. First, this paper starts with presenting the converged network architecture and especially the concept of virtual ONU-BS (VOB). Then, it identifies some unique research issues in this converged network. Second, the paper investigates a dynamic bandwidth allocation (DBA) scheme and its closely associated research issues. This DBA scheme takes into consideration the specific features of the converged network to enable a smooth data transmission across optical and wireless networks, and an end-toend differentiated service to user traffics of diverse QoS (Quality of Service) requirements. This QoS-aware DBA scheme supports bandwidth fairness at the VOB level and class-of-service fairness at the 802.16 subscriber station level. The simulation results show that the proposed DBA scheme operates effectively and efficiently in terms of network throughput, average/maximum delay, resource utilization, service differentiation, etc.     

QoS Control Schemes for Two-Stage Ethernet Passive Optical Access Networks

Ethernet passive optical networks (EPONs) have emerged as the one of the most promising candidates for next-generation access networks. These new architectures couple low-cost optics with advanced edge electronics to offer vastly improved scalability over competing digital subscriber line and cable modem offerings. This paper proposes several novel architectural enhancements for EPON, which will help increase the viability of optical access over a broader range of subscriber access scenarios. Specifically, this paper proposes a two-stage EPON architecture that allows more end-users to share an optical line terminal link, and enables longer access reach/distances (beyond the usual 25 km distance). In addition, a new dynamic bandwidth allocation (DBA) algorithm is proposed to effectively allocate bandwidths between end users. This DBA algorithm can support differentiated services in a network with heterogeneous traffic. We conduct detailed simulation experiments to study the performance and validate the effectiveness of the proposed architecture and algorithms.     

有线电视双向网接入技术选择

EPON技术因其高带宽、无源分配、易维护、支持多业务等优势,近年来正在成为宽带接入的主要技术之一,也非常适合于有线电视网络开展双向数据业务。在接入技术方面有EoC、LAN,部分广电有线电视网络已经进行了基于Cable Modem方式的HFC双向网改造,那么如何选择宽带接入方式呢？对HFC、EPON以及几种接入技术做技术分析、投入成本分析以及网络现状分析,以此选择适合有线电视网宽带接入的技术方式。     

Dynamic bandwidth allocation for quality-of-service over Ethernet PONs

Ethernet-based passive optical network (EPON) technology is being considered as a promising solution for next-generation broadband access networks due to the convergence of low-cost Ethernet equipment and low-cost fiber infrastructures. A major feature for this new architecture is the use of a shared transmission media between all users; hence, medium access control arbitration mechanisms are essential for the successful implementation of EPON: i.e., to ensure a contention-free transmission and provide end users with equal access to the shared media. We propose to use the multipoint control protocol defined by the IEEE 802.3ah task force to arbitrate the transmission of different users, and we present different dynamic bandwidth allocation (DBA) algorithms to allocate bandwidths effectively and fairly between end users. These DBA algorithms are also augmented to support differentiated services, a crucial requirement for a converged broadband access network with heterogeneous traffic. We show that queueing delays under strict bandwidth allocation algorithms result in an unexpected behavior for certain traffic classes, and we suggest the use of DBA with appropriate local queue management to alleviate this inappropriate behavior. We conduct detailed simulation experiments to study the performance and validate the effectiveness of the proposed protocols.     

一种WDM-EPON的DBA算法及其改进

介绍了一种WDM-EPON的DBA算法并对其进行改进,改进的算法能根据ONU端不同的业务类型情况对波长和带宽进行分配,以支持多业务接入的QoS,从而使整个网络带宽的得到更公平有效地分配,最后用OPNET进行仿真,结果表明改进的算法能为不同等级的业务流提供相应的带宽,时延等QoS保证.     

Review on Dynamic Bandwidth Allocation of GPON and EPON

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.