Enhanced Dynamic Bandwidth Allocation Algorithm in Ethernet Passive Optical Networks

As broadband access is evolving from digital subscriber lines to optical access networks, Ethernet passive optical networks (EPONs) are considered a promising solution for next generation broadband access. The point‐to‐multipoint topology of EPONs requires a time‐division multiple access MAC protocol for upstream transmission. In this paper, we propose a new enhanced dynamic bandwidth allocation algorithm with fairness called EFDBA for multiple services over EPONs. The proposed algorithm is composed of a fairness counter controller and a fairness system buffer in the optical line terminal. The EFDBA algorithm with fairness can provide increased capability and efficient resource allocation in an EPON system. In the proposed EFDBA algorithm, the optical line termination allocates bandwidth to the optical network units in proportion to the fairness weighting counter number associated with their class and queue length. The proposed algorithm provides efficient resource utilization by reducing the unused remaining bandwidth made by idle state optical network units.     

Cyclic Polling-Based Dynamic Bandwidth Allocation for Differentiated Classes of Service in Ethernet Passive Optical Networks

Ethernet passive optical networks (EPONs) are an emerging access network technology that provides a low-cost method of deploying optical access lines between a carrier's central office and customer sites. Dynamic bandwidth allocation (DBA) provides statistical multiplexing between the optical network units for efficient upstream channel utilization. To support dynamic bandwidth distribution, a cyclic polling-based DBA algorithm for differentiated classes of service in EPONs is proposed. It is shown that an interleaved polling scheme severely decreases downstream channel capacity for user traffic when the upstream network load is low. To obtain realistic simulation results, synthetic traffic that exhibits the properties of self-similarity and long-range dependence is used. Network performance under various loads is analyzed. Specifically, frame delays for different classes of traffic are considered.     

EPON系统的动态带宽分配算法

针对EPON系统上行链路多个ONU共享带宽的拓扑结构,分析了制定带宽分配策略所需考虑的基本因素,介绍了一种新的动态带宽分配算法,通过动态请求分配机制,实现上行链路的高效利用。     

一种EPON-WiMAX融合网络带宽分配算法

文中提出了一种应用于EPON和WiMAX的融合网络,实现用户多优先级业务区分并保证用户QoS的动态带宽分配算法。算法让EPON网络和WiMAX网络协同分配带宽,在EPON网络带宽分配的过程中加入WiMAX网络的带宽分配。整体算法使得因得不到足够带宽而受到影响的用户数保持在最小,同时加入令牌机制兼顾了用户之间的公平性。文中在现有融合网络框架的基础上提出算法,并给出了算法的具体设计步骤,详细分析了带宽申请和分配的过程,讨论了算法的优越性。     

提高带宽利用率和降低延时的动态带宽分配算法

EPON(Ethernet Passive Optical Network)由于它的低成本和高带宽,一直被人们认为是下一代接入网的解决方案.而动态带宽分配算法(DBA)一直是人们研究的热点.本论文回顾了最近几年已提出的DBA算法,并提出一种新的提高带宽利用率和降低延时的DBA算法.OLT依据接收到的REPORT帧判断ONU缓存队列的大小,如果队列小于最大传输窗口则先授权.在仿真中可以看到采取此算法可以降低延时并提高了带宽利用率.     

基于Ethernet无源光接入网关键技术的研究

以Ethernet为基础的无源光网络（Ethernet－PON）是未来实现宽带，多业务综合接入的重要技术手段，本文分析了EPON系统的基础结构和个组成部分，所支持的业务，实现系统所需要解决的关键技术及实现方法，同时对系统设计时所需考虑的一些重要问题进行了探讨。     

以太网无源光网络中的突发模式

以太网无源光网络可以实现低成本、远距离的宽带接入。本阐述了以太网无源光网络(EPON)的结构、原理并提出上行突发模式方案。     

Priority-based dynamic bandwidth allocation in Ethernet Passive Optical Networks

In this article, new Dynamic Bandwidth Allocation (DBA) algorithms which give high priority to some ONUs corresponding to important agencies are studied in order to manage emergency cases causing severe network traffic. In order to deal with such cases, the network state is divided into two states, namely the normal and the emergency states. We apply the Weighted Round Robin (WRR)-based algorithm to the normal state, and three priority-based DBA algorithms are applied to the emergency state. These algorithms are different from each other according to the mode of protecting non-priority ONUs from starving. Each algorithm is analyzed in terms of utilization of the uplink bandwidth and the average packet delay. Simulation and theoretical results show that the proposed algorithms are working properly at the emergency state and can satisfy more stringent QoS requirements than WRR algorithms.

光接入网中动态带宽分配算法（DBA）分析

主要分析3种DBA算法：间插轮询（IPACT）带宽分配算法算法、BGP算法、基于比例分配的支持服务等级区分带宽分配算法。分析其原理、上行通道的利用率、时延特性及对不同业务等级之间公平性的影响。并通过对3种算法的性能进行分析得出各自优缺点的结论。     

基于国际标准的新型EPON动态带宽分配方案

提出一种新的基于国际标准和区分服务(Differentiated Service)的以太无源光网络(EPON)动态带宽分配(dynamic bandwidth allocation,DBA)方案,该方案不仅能够在上行方向为多个光网络单元(Optical Network Unit,ONU)高效并公平地分配有限的带宽,而且能够最大限度地保证不同ONU间及不同通信等级间的公平性以及高等级通信的服务质量(QoS)要求.仿真结果证明,与现有算法相比,本算法在延时和利用率方面均有改进,在重负荷情况下改进更明显.     

Hierarchical Dynamic Bandwidth Allocation Algorithm for Multimedia Services over Ethernet PONs

In this paper, we propose a new dynamic bandwidth allocation (DBA) algorithm for multimedia services over Ethernet PONs (passive optical networks). The proposed algorithm is composed of a low‐level scheduler in the optical network unit (ONU) and a high‐level scheduler in the optical line terminal (OLT). The hierarchical DBA algorithm can provide expansibility and efficient resource allocation in an Ethernet PON system in which the packet scheduler is separated from the queues. In the proposed DBA algorithm, the OLT allocates bandwidth to the ONUs in proportion to the weight associated with their class and queue length, while the ONU preferentially allocates its bandwidth to queues with a static priority order. The proposed algorithm provides an efficient resource utilization by reducing the unused remaining bandwidth caused by the variable length of the packets. We also define the service classes and present control message formats conforming to the multi‐point control protocol (MPCP) over an Ethernet PON. In order to evaluate the performance, we designed an Ethernet PON system on the basis of IEEE 802.3ah “Ethernet in the first mile” (EFM) using OPNET and carried out simulations. The results are analyzed in terms of the channel utilization, queuing delay, and ratio of the unused remaining bandwidth.     

LR-PON中改进的节能动态带宽分配算法

长距离无源光网络(Long-reach Passive Optical Networks,LR-PON)的覆盖范围超过100 km,光网络单元(Optical Network Units,ONU)在一个轮询周期中处于空闲状态的时间较长.如果使处于空闲状态的ONU进入低功耗(休眠或假寐)模式,可以降低ONU的能耗.基于此,文章提出一种改进的节能动态带宽分配算法.该算法通过改变ONU的调度顺序,使得ONU在上下行传输结束后能够立刻进入休眠状态,而无需等待授权帧的到达,从而延长ONU的休眠时间.仿真结果表明:所提出算法能够降低ONU能耗和下行数据包平均时延.     

一种在EPON中支持多业务接入的DBA公平算法

上行带宽的动态带宽分配是以太网无源光网络(EPON)系统的一个重要研究领域,文章提出了一种区分业务优先等级的动态周期轮询算法.该算法保证了高优先级业务的实时传输,同时为中、低优先级业务提供了基本的带宽,兼顾了动态带宽分配的效率和公平性.文中通过公式推导,给出了算法的具体实现过程,从理论上证明了新算法的可行性.     

EPON系统中VLAN的设计与实现

EPON(以太无源光网)作为一种新的接入技术,利用VLAN(虚拟局域网)可以满足用户对多种业务的需求,同时也可优化网络性能和满足同一EPON系统多运营商接入的需求。本文首先介绍了EPON中交换芯片对VLAN的支持,接着从用户空间、内核空间和芯片驱动三个层面描述了VLAN的设计,从而实现VLAN的配置与动态管理。     

EPON的OAM协议原理与设计方案

讨论了EPON的OAM协议原理与设计实现,给出了EPON中OAM的链路检测、远程错误指示、远程回环等功能的设计方案。     

EPON中安全机制的研究

基于以太网的无源光网络(EPON)是一个点到多点的系统,面临着很多安全隐患。针对EPON系统中存在的几种安全威胁,提出了一种解决EPON安全隐患的综合性方案。     

一种WDM-PON系统中基于SLA的动态带宽算法

文章提出了一种基于业务等级协议(SLA)的动态带宽分配算法,该算法根据SLA为光网络单元(ONU)分配带宽权重和相应的优先权,确保了ONU的带宽分配和服务质量,改善了网络的性能,满足了网络业务的QoS要求.最后,通过仿真证明了这种算法的正确性.     

一种保证QoS的10G-EPON动态带宽分配算法

随着高清IPTV、在线游戏等业务的发展,用户对于带宽的需求日益增加,10G-EPON技术应运而生。与传统的EPON系统一样,10G-EPON系统的动态带宽分配问题仍然十分关键。带宽分配方式的选择对于如何避免传输冲突,提高系统的带宽利用率且保障服务质量都非常重要。在已有算法的基础之上,提出一种改进型动态带宽分配算法。该算法重点确保高优先级业务的服务要求,在一定程度上体现了不同等级ONU之间的公平性,提高了上行带宽利用率。     

无源光网络标准发展及关键技术研究

无源光网络(Passive Optical Network,PON)作为当今接入网的主要技术解决方案,具有带宽使用效率高、传输距离远、抗干扰能力强等特点.通过研究PON技术的发展动态,本文首先归纳了各种PON技术的产生背景和应用特点,整理出各技术间的连接关系及主要标准;其次介绍了PON技术的帧结构,并对带宽、波长、传输模式等PON技术的主要参数进行了汇总;然后将国内外研究热点进行划分,围绕媒体访问控制协议、帧结构、动态带宽分配算法、节能机制等关键技术,阐述了其研究现状及在PON中的重要作用;最后对PON技术的发展趋势进行了展望.     

Inter‐ONU Bandwidth Scheduling by Using Threshold Reporting and Adaptive Polling for QoS in EPONs

I dynamic bandwidth allocation (DBA) scheme, an inter–optical network unit (ONU) bandwidth scheduling, is presented to provide quality of service (QoS) to different classes of packets in Ethernet passive optical networks (EPONs). This scheme, referred to as TADBA, is based on efficient threshold reporting from, and adaptive polling order rearranging of, ONUs. It has been shown that the network resources are efficiently allocated among the three traffic classes by guaranteeing the requested QoS, adaptively rearranging the polling orders, and avoiding nearly all fragmentation losses. Simulation results using an OPNET network simulator show that TADBA performs well in comparison to the available allocation scheme for the given parameters, such as packet delay and channel utilization.