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动态时隙分配算法一、概述动态时隙分配算法（Dynamic Slot Allocation Algorithm）是一种用于移动通信网络的调度方法，其主要目的是最大化信道的利用率和保证通信质量。
在无线通信中，由于信道资源有限，如何优化资源的利用率成为了一个重要问题。
动态时隙分配算法可以针对特定的应用场景进行参数优化，从而达到较好的效果。
二、算法分类1. 静态时隙分配算法静态时隙分配算法是指在通信网络中，按照一定的规律预先分配时隙，从而实现对信道资源的有效利用。
该算法优点在于可以在实现过程中保证通信质量，缺点则是不能适应复杂的网络环境调度。
2. 动态时隙分配算法动态时隙分配算法是针对静态时隙分配的缺点而发展的一种更为灵活的调度方法。
它在通信网络中不断地重新分配时隙，以根据当前的网络负载情况优化资源利用的效果。
三、算法原理动态时隙分配算法能够快速适应网络环境的变化，主要原理是通过不断地监测网络的状态和分类指标，以便进行时隙的动态分配。
该算法通常包含以下几个步骤：1. 预测网络状态针对移动通信网络中各种状态的不同，动态时隙分配算法需要通过预测的方式对网络状态进行预测和分类。
2. 时隙分配根据当前的网络状态预测，动态时隙分配算法会自动分配信道资源，并根据这些资源对网络进行调度。
3. 监测网络状态动态时隙分配算法会在不断监测网络状态的前提下，尽可能地根据网络的实际性能进行自我调节和优化。
四、算法应用动态时隙分配算法在无线通信中具有很强的应用前景，尤其是在移动宽带通信中的应用更为广泛。
它可以适应不同类型的应用，如语音通信、视频传输、数据传输等，并能够保证及时快速地适应网络环境的变化，从而保证了用户通信的质量和网络资源的利用效率。
五、算法局限动态时隙分配算法在实际应用中还存在一些局限，例如：1. 复杂性动态时隙分配算法的实现需要考虑多种移动通信应用场景，难以应对各种情况的需求。
2. 实时性在移动通信中，网络的状态会发生不断的变化，因此动态时隙分配算法必须具有高度的实时性，否则就无法保证通信的质量。
HINOC网络中的动态带宽调度算法作者：彭武熹施韵万立来源：《电脑知识与技术》2013年第05期摘要：该文首先介绍了动态带宽分配算法的必要性，而后对HINOC网络中动态带宽分配算法进行了讨论，最后提出一种基于HINOC网络环境的动态带宽算法。
关键词： HINOC；动态带宽分配；三网融合中图分类号：TP393 文献标识码：A 文章编号：1009-3044（2013）05-1008-021 综述同轴电缆宽带接入技术（HIgh performanceNetwork Over Coax， HINOC），在光纤到楼（FTTB）的网络结构基础上，利用小区楼道和户内已经敷设、分布广泛的有线电视同轴电缆，构建高速的信息接入网，目前已被我国正式确定为三网融合标准之一[1]。
在HINOC网络中，单信道能提供的最大理论带宽为112Mbps，最多支持32个用户，信道接入采用时分复用方式。
用户在线时间不同，带宽需求也各不相同，为保证各个用户能有较好的用户体验，必须要设计一种高效、公平、稳定的带宽动态分配算法（Dynamic Bandwidth Allocation，DBA）[1]。
2 基于HINOC网络的DBA算法研究HINOC网络由一个HB（HINOC Bridge）及若干个HM（HINOC Modem）组成，HB上联广域网，HM连接用户家内上网终端，二者之间通过同轴电缆连接。
逻辑拓扑采用星型结构，如图1所示：其中HB为主节点，HM为从节点，HINOC网络链路接入采用时分复用方式，以64毫秒为一个周期，以下简称PD周期。
各PD周期之间是相互独立的，每周期进行一次网同步。
HB 和HM间使用MAP帧（Media Access Packet）完成DBA功能，HB下发MAP帧发布信道规划，HM根据MAP帧的规划进行数据收发，以避免信道冲突[3]。
本文提出的HINOC网络DBA算法基于令牌桶设计。
以HM的发送接收时间作为带宽的衡量标准，单位为ms。
gpon dba原理GPON DBA原理一、引言GPON（Gigabit Passive Optical Network）是一种基于光纤传输的无源光网络技术，它通过光纤将光信号传输到用户处，实现高速宽带接入。
在GPON中，DBA（Dynamic Bandwidth Allocation）是一项关键技术，用于实现光纤上下行带宽的动态分配。
本文将介绍GPON DBA的原理和作用。
二、GPON DBA的作用GPON DBA的主要作用是根据用户的需求和网络的实际情况，合理分配上下行带宽资源，以提高网络的效率和带宽利用率。
通过动态分配带宽，DBA可以根据用户的实际需求，在不同的时间段和不同的用户之间进行公平的带宽分配，从而优化网络性能。
三、GPON DBA的原理1. 网络中的OLT（Optical Line Terminal）设备负责与用户终端进行通信。
OLT通过PON（Passive Optical Network）光纤将信号传输到ONU（Optical Network Unit）终端。
2. OLT设备根据ONU上报的带宽需求和网络负载情况，动态分配上下行带宽资源。
DBA算法根据不同的因素进行带宽分配决策，如用户的业务类型、优先级、剩余带宽等。
3. DBA算法根据实时的带宽需求进行调整，以适应网络的变化。
当网络负载较小时，DBA会分配更多的带宽给用户，提高用户的传输速率；当网络负载较大时，DBA会进行动态的带宽调整，以保证网络的稳定性和公平性。
4. DBA算法会根据OLT设备和ONU终端的能力进行带宽分配，以充分利用网络资源。
例如，对于具有高速上行需求的用户，DBA 会优先分配更多的上行带宽；对于具有高速下行需求的用户，DBA 会优先分配更多的下行带宽。
5. DBA算法还可以对不同类型的业务进行优先级排序，以保证重要业务的带宽需求得到满足。
例如，对于视频会议或在线游戏等对时延敏感的业务，DBA会优先分配更多的带宽，以确保业务的稳定运行。
通信行业英语中英对照手册(D)D-A Digital-Analog 数模D-D Digital-Digital 数数D/A Digital / Analog 数字/模拟DA Data Access 数据存取DA Data Acquisition 数据采集DA Demand Assignment 按需分配DA Destination Address 目的地址DAA Data Access Arrangement 数据存取装置DAB Digital Audio Broadcast 数字音频广播DAC Data Acquisition Center 数据采集中心DAC Data Acquisition Computer 数据采集计算机DAC Data Acquisition Controller 数据采集控制器DAC Digital Analog Converter 数模转换器DACI Direct Adjacent Channel Interference 相邻信道的直接干扰DACN Desk Area Computer Network 桌域计算机网DACS Digital Access & Cross-connect System 数字接入交叉连接系统DAD Digital Audio Disk 数字音频磁盘DAE Data Acquisition Equipment 数据采集设备DAE Distributed Agent Environment 分布式代理环境DAF Destination Address Field 目的地址字段DAI Data Adapter Interface 数据适配器接口DAI Distributed Artificial Intelligence 分布式人工智能DAL Data Access Line 数据存取线路DAM Data Addressed Memory 数据定址存储器DAM DECT Authentication Module DECT认证模块DAMA Demand Assigned Multiple Access 按需分配多址访问DAMPS Digital Adanced Mobile Phone System 数字高级移动电话系统DAP Data Access Point 数据接入点DAP Data Access Protocol 数据存取协议DAP Data Acquisition Processor 数据采集处理器DAP Directory Access Protocol 目录访问协议DAR Dynamic Alternate Routing 动态迂回路由DARC DAta Radio Channel 数据无线信道DAT Digital Audio Tape 数据音频磁带DAVIC Digital Audio / Video International Council 国际数字音频/视频理事会DAVID Digital Audio / Video Interactive Decoder 数字音频/视频交互式解码器DAWS Digital Advanced Wireless Service 数字高级无线服务DB DataBase 数据库DBA DataBase Administrator 数据库管理程序DBA Dynamic Bandwidth Allocation 动态带宽分配DBC Dynamic Bandwidth Controller 动态带宽控制器DBMS DataBase Management System 数据库管理系统DBN DataBase Network 数据库网络DBPSK Differentially coherent Binary PSK 差分相干二进制相移键控DBR Deterministic Bit Rate 确定性比特率DBS Direct Broadcast Satellite 直播卫星DBS Domestic Base Station 国内基站DBX Digital Branching & CroSs-connect equipment 数字分路和交叉连接设备DC Data Compression 数据压缩DC Digital Convergence 数字汇聚DC Dispersion Compensation 色散补偿DC Down Compatibility 向下兼容DC Driving Circuit 驱动电路DC Drop Cable 引入缆DCA Dynamic Channel Allocation 动态信道分配DCC Data Communication Channel 数据通信信道DCC Data Country Code 数据国家码DCC Digital Control Channel 数字控制信道DCC Digital Cross Connect 数字交叉连接DCCH Dedicated Control CHannel 专用控制信道DCCN Distributed Computer Communication Network 分布式计算机通信网络DCD Data Communication Device 数据通信装置DCE Data Circuit Equipment 数据电路设备DCE Data Circuit terminating Equipment 数据电路端接设备DCE Data Communication Equipment 数据通信设备DCE Data Connection Equipment 数据连接设备DCE Distributed Computing Environment 分布式计算环境DCF Data Communication Function 数据通信功能DCF Dispersion Compensation Fiber 色散补偿光纤DCL Digital Channel Link 数字信道链路DCLU Digital Carrier Line Unit 数字载波线路单元DCM Data Communication Module 数据通信模块DCM Data Communication Multiplexer 数据通信复用器DCM Dispersion Compensator Module 色散补偿模块DCM Dynamic Connection Management 动态连接管理DCMA Data Communication Mesh Architecture 数据通信网状结构DCME Digital Circuit Multiplication Equipment 数字线路多路复用器DCN Data Communication Network 数据通信网DCN Digital Communication Network 数字通信网DCNA Data Communication Network Architecture 数据通信网络体系结构DCOM Distributed Component Object Model 分布式构件对象模型DCP Data Communication Processor 数据通信处理器DCP Data Coordinating Point 数据协调点DCP Digital Communication Protocol 数字通信协议DCP Distributed Communication Processor 分布式通信处理器DCPA Distributed Call Processing Architecture 分布式呼叫处理结构DCPN Domestic Customer Premises Network 国内用户驻地网DCPS Data Compression Processing System 数据压缩处理系统DCPSK Differentially Coherent Phase-Shift Keying 差分相干相移键控DCR Destination Call Routing 按目标选择路由DCR Dynamically Controlled Routing 动态控制路由DCS Desktop Conferencing System 桌式会议系统DCS Digital Cellular System 数字蜂窝系统DCS Digital Communication System 数字通信系统DCS Digital Cross-connect System 数字交叉连接系统DCS Dynamic Channel Selection 动态信道选择DCS Dynamic Channel Stealing 动态信道挪用DCT Data Communication Terminal 数据通信终端DCT Discrete Cosine Transformation 离散余弦变换DCTU Directly Connected Test Unit 直接连接测试单元DCU Digital Connection Unit 数字连接单元DCU Dual Carrier Unit 双载波单元DD-EDFA Dispersion-Decreasing Erbium Doped Fiber Amplifier 低色散掺铒光纤放大器DDB Distributed DataBase 分布式数据库DDC Digital Data Communication 数字数据通信DDC Digital Data Converter 数字数据转换器DDCMP Digital Data Communications Message Protocol 数字数据通信消息协议DDD Digital Data Demodulator 数字数据解调器DDD Direct Distance Dialing 长途直拨DDE Dynamic Data Exchange 动态数据交换DDF Digital Distribution Frame 数字配线架DDF Dispersion-Decreasing Fiber 低色散光纤DDHB Distributed Dynamic Hypermedia Browser 分布式动态超媒体浏览器DDI Direct-Dialing-In 直接拨入DDL Digital Data Line 数字数据线DDL Digital Data Link 数字数据链路DDN Digital Data Network 数字数据网DDN Distributed Data Network 分布式数据网DDNS Dynamic Domain Name System 动态域名系统DDOS Distributed Deny Of Service 分布式拒绝服务DDOV Digital Data Over Voice 话音传送数字数据DDP Datagram Delivery Protocol 数据报投递协议DDP Distributed Data Processing 分布数据处理DDP Distributed Data Processor 分布式数据处理器DDS Digital Data Service 数字数据服务DDS Digital Data System 数字数据系统DDS Direct Digital Satellite 直播数字卫星DECT Digital Enhanced Cordless Telecommunications 数字增强型无绳电信DED Dynamically Established Data link 动态建立数据链路DEDF Distributed Erbium-Doped Fiber 分布式掺铒光纤DEDFA Distributed Erbium-Doped Fiber Amplifier 分布式掺铒光纤放大器DEK Data Encryption Key 数据加密密钥DEN Directory-Enabled Networking 基于目录的连网DES Data Encryption Standard 数据加密标准DFAS Distributed Frame Alignment Signal 分布式帧排列信号DFB Distributed Feed Back 分布反馈DFC Data Flow Control 数据流控制DFCF Dispersion Flat Compensation Fiber 色散平坦补偿光纤DFE Decision Feedback Equalizer 判决反馈均衡器DFF Dispersion Flattened Fiber 色散平坦光纤DFG Differential-Frequency-Generation 差分频率产生DFI Digital Facility Interface 数字设备接口DFL Data Flow Controller 数据流控制器DFOS Distributed Fiber Optic Sensing 分布式光纤传感DFP Distributed Function Plane 分布式功能平面DFS Decision Feedback System 判决反馈系统DFS Dedicated File Server 专用文件服务器DFS Distributed Fiber Sensor 分布式光纤传感器DFSK Differential Frequency Shift Keying 差分频移键控DFSK Double Frequency Shift Keying 双频移键控DFSM Dispersion Flattened Single Mode 色散平坦单模DFT Delayed-First-Transmission 延迟优先传输DFU Data Facilities Unit 数字设备单元DGPS Difference Global Positioning System 差分全球定位系统DHCP Dynamic Host Configuration Protocol 动态主机配置协议DHCP Dynamic Host Control Protocol 动态主机控制协议DHN Digital Home Network 数字家庭网DHTML Dynamic HTML 动态HTMLDHW Down HighWay 下行公共信道DI Digital Interface 数字接口DI Dispersion-Increasing 色散增加DIB Data Input Bus 数据输入总线DIB Device Independent Bitmap 与设备无关位图DIB Directory Information Base 目录信息库DICH Dedicated Information CHannel 专用信息信道DICS Digital Image Correction System 数字图像校正系统DID Direct In-Dialling 直接拨号DII Dynamic Invocation Interface 动态调用接口DINA DIgital Network Analyzer 数字网络分析程序DINOS DIstributed Network Operating System 分布式网络*作系统DIP Digital Image Processing 数字图像处理DIRMA Digital Impulse Radio Multiple Address 数字脉冲无线多址DIS Digital Identification Signal 数字识别信号DISP Directory Information Shadowing Protocol 目录信息隐匿协议DIT Direct Image Technical 直接成像技术DIT Directory Information Tree 目录信息树DL Data Link 数据链路DL Down Link 下行链路DL Dynamic Link 动态链接DLC Data Link Control 数据链路控制DLC Data-Link-Connection 数据链路连接DLC Digital Loop Carrier 数字环路载波DLC Dynamic Load Control 动态负载控制DLCI Data Link Connection Identifier 数据链路连接标识符DLCI Digital Loop Carrier Interface 数字环路载波接口DLCU Data Link Control Unit 数据链路控制单元DLE Data Link Entity 数据链路实体DLE Digital Local Exchange 本地数字交换DLE Distributed LAN Emulation 分布式局域网仿真DLI Data Link Interface 数据链路接口DLIS Digital Link Interface Software 数字链路接口软件DLL Data Link Layer 数据链路层DLL Delay Lock Loop 延迟锁定环路DLL Digital Leased Line 数字租用线路DLL Digital Local Line 数字本地线路DLL Dynamic Linked Library 动态链接程序库DLN Double Loop Network 双环网络DLS Data Link Service 数据链路服务DLS Digital Line Section 数字线路段DLSAP Data Link Service Access Point 数据链路服务接入点DLSDU Data Link Service Data Unit 数据链路服务数据单元DLT Digital Link T ester 数字链路测试器DLTU Digital Line and Trunk Unit 数字线路和中继线单元DM Data Mining 数据挖掘DM Data Multiplexer 数据多路复用器DM Delta Modulation 增量调制DM Disconnected Mode 断开方式DM Dispersion Management 色散管理DMA Direct Memory Access 存储器直接存取DMAC Distributed Multi-Agent Coordination 分布式多代理协作DMB Digital Media Broadcasting 数字媒体广播DMC Data Multiplex Channel 数据复用信道DMC Digital Media Center 数字媒体中心DMCI Digital Media Control Interface 数字媒体控制接口DMCWS Distributed Multimedia Cooperative Writing System 分布式多媒体协同编著系统DMD Differential Mode Delay 差分模式时延DME Digital Multiplex Equipment 数字复用设备DME Distributed Management Environment 分布式管理环境DMF Dispersion-Managed Fiber 色散管理光纤DMIS Distributed Multimedia Information System 分布式多媒体信息系统吐血推荐：通信英语缩语手册（DMK-DXI）DMK Distributed Multimedia Kiosk 分布式多媒体触摸屏服务DML Data Manipulation Language 数据*作语言DMS Data Multiplexing System 数据复用系统DMS Demand Multimedia System 多媒体点播系统DMS Distributed Multimedia Service 分布式多媒体服务DMSD Digital Multi Standard Decoder 数字多标准译码器DMSD Digital Multi Standard Decoding 数字多制式解码DMSS Data Multiplexing SubSystem 数据复用子系统DMT Discrete Multi-Tone 离散多音DN Destination Network 目标网络DN Directory Number 电话簿号码DN Distributed Network 分布式网络DN Distribution Network 分配网DN Domain Name 域名DN Downstream Node 下行结点DNA Data Network Address 数据网络地址DNA Destination Node Address 目标结点地址DNA Digital Network Architecture 数字网络结构DNA Distributed Network Architectrue 分布式网络结构DNBR Dialing NumBeR 拨号号码DNC Dynamic Network Collection 动态网络收集DNCC Data Network Control Center 数据网络控制中心DNCS Distributed Network Control System 分布式网络控制系统DNG Digital News Gathering 数字新闻采访DNHR Dynamic NonHierarchical Routing 动态无级路由选择DNI Data Network Interface 数据网接口DNI Desktop Network Interface 桌面网络接口DNI Distributed Network Interface 分布式网络接口DNIC Data Network Identification Code 数据网标识码DNM Distributed Network Management 分布式网络管理DNMEP Data Network Modified Emulator Program 数据网络改进型仿真程序DNR Digital Noise Rejection 数字噪声抑制DNS Data Network Service 数据网络业务DNS Distributed Network System 分布式网络系统DNS Domain Name Server 域名服务器DNS Domain Name Service 域名服务DNS Domain Name System 域名系统DNTS Data Network Test System 数据网络测试系统DOD Data On Demand 按需提供数据DOD Direct Outward Dialing 直接向外拨号DOMSAT DOMestic SATellite 国内卫星DONA Decentralized Open Network Architecture 分散开放式网络体系结构DOS Denial Of Service 拒绝服务DOV Data Over Voice 话音传数据DP Data Processing 数据处理DP Detection Point 检测点DP Distribution Point 分配点DPCCH Dedicated Physical Control CHannel 专用物理控制信道DPCM Differential Pulse Code Modulation 差分脉码调制DPCN Digital Private Circuit Network 数字专用电路网DPDCH Dedicated Physical Data CHannel 专用物理数据信道DPE Distributed Processing Environment 分布式处理环境DPG Digital Pair Gain 数字线对增益DPHCH Dedicated PHysical CHannel 专用物理信道DPI Dot Per Inch 每英寸点数DPL Data Protection Layer 数据保护层DPN Dual-Private Network 双向专用网络DPN Dynamical Path Network 动态路径网DPON Domestic PON 国内无源光网络DPS Distributed Packet Switching 分布式分组交换DPS Dynamic Packet State 动态分组状态DPSK Diffential Phase Shift Keying 差分相移键控DPT Dynamic Packet Transport 动态分组传送DQDB Distributed Queue Dual Bus 分布式队列双总线DQPSK Differential Quadrature Phase Shift Keying 差分四相相移键控DR Deflection Routing 改向路由选择DR Direct Route 直达路由DR Disconnect Request 挂断请求DR Dynamic Routing 动态选路DRAM Dynamic Random Access Memory 动态随机存取存储器DRID Destination Routing IDentifier 目的路由选择标识符DRP Distribution Resource Planning 分配资源计划DRP Dynamic Routing Protocol 动态选路协议DRS Digital Radio System 数字无线电系统DS Data Stream 数据流DS Data Switching 数据交换DS Differentiated Service 区分业务DS Direct Sequence 直接序列DS Directory Services 目录服务DS Dispersion Shift 色散位移DS document．nbspStorage 文件存储DS-CDMA Direct Sequence CDMA 直接序列CDMADS-SMF Dispersion Shifted Single Mode Fiber 色散位移单模光纤DSA Digital Signature Algorithm 数字签名算法DSA Directory System Agent 目录系统代理DSAA DECT Standard Authentication Algorithm DECT标准认证算法DSAMA Dynamic Slot Allocation Multiple Access 动态时隙分配多址接入DSAP Data link Service Access Point 数据链路业务接入点DSB Direct Satellite Broadcast 直接卫星广播DSBSC Double Side-Band Suppressed Carrier 双边带抑制载波DSC Decision Support Center 决策支持中心DSC Direct Satellite Communications 直接卫星通信DSCA DECT Standard Cipher Algorithm DECT标准密码算法DSCF Dispersion Slope Compensating Fiber 色散斜率补偿光纤DSE Data Switching Exchange 数据交换机DSF Dispersion Shifted Fiber 色散位移光纤DSI Digital Speech Interpolation 数字话音内插DSL Digital Subscriber Line 数字用户线DSLAM Digital Subscriber Line Access Multiplexer 数字用户线接入复用器DSM Digital Switch Module 数字交换模块DSM Direct-Sequence Modulation 直接序列调制DSM Dynamic Single Mode 动态单模DSN Digital Switching Network 数字交换网络DSN Distributed Switching Node 分布式交换结点DSP Digital Signal Processing 数字信号处理DSP Digital Signal Processor 数字信号处理器DSP Digital Sound Processor 数字声音处理器DSP Directory System Protocol 目录系统协议DSP Domain Specific Part 域专用区DSR Dynamic Source Routing 动态源路由DSRS Data Signal Rate Selection 数据信号速率选择DSS Data Storage System 数据存储系统DSS Decision Support System 决策支持系统DSS Digital Signature Standard 数字签名标准DSS Digital Subscriber Service 数字用户业务DSS Direct Satellite System 直播卫星系统DSS Directory Service System 目录服务系统DSS1 Digital Subscriber Signaling system No.1 1号数字用户信令系统DSS2 Digital Subscriber Signaling system No.2 2号数字用户信令系统DSSG Decision Support System Generator 决策支持系统生成器DSSMAN Data Service Specific MAN 数据业务专用城域网DSSS Direct Sequence Spread Spectrum 直接序列扩频DSSSMA DSSS Multiple Access 直接序列扩频多址接入DST Dispersion Supported Transmission 色散支持传输DST Dynamic Soliton Transmission 动态孤子传输DSTM Dynamic Synchronous Transfer Mode 动态同步转移模式DSU Data Service Unit 数据业务单元DSU Data Switch Unit 数据交换单元DSU Digital Service Unit 数字业务单元DSU Digital Switching Unit 数字交换单元DSV Data Steal into Voice 数据插入语音DSVD Digital Simultaneous Voice & Data 语音和数据同时数字传输DSVMA Data Steal into Voice Multiple Access 数据插入语音多址接入DSX Digital Singals CroSs-connect 数字信号交叉连接DT Data Terminal 数据终端DT Data Transfer 数据传送DT Digital Terminal 数字终端DT-PDU DaT a Protocol Data Unit 数据协议数据单元DT-WDMA Dynamic Time Wavelength Division Multiple Access 动态时间波分多址接入DTE Data Terminating Equipment 数据终端设备DTF Delayed TransFer 延迟转移DTF Digital Transmission Facility 数字传输设备DTF Dispersion-T ailored Fiber 色散预定光纤DTF Dispersion-T apered Fiber 色散锥形光纤DTH Direct To Home 直接到户DTI Data Transmission Interface 数据传输接口DTI Digital Terminal Interface 数字终端接口DTI Digital Transmission Interface 数字传输接口DTI Digital Trunk Interface 数字中继接口DTIM Digital Transmission Interface Module 数字传输接口模块DTL Data Transmission Line 数据传输线路DTLM Digital Trunk Line Module 数字中继线路模块DTM Digital Trunk Module 数字中继模块DTM Dynamic synchronous Transfer Mode 动态同步转移模式DTMF Dual Tone Multiple Frequency 双音多频DTO Data Transfer Operation 数据转移*作DTP Data Transfer Phase 数据转移阶段DTP Data Transfer Protocol 数据转移协议DTR Digital Trunked Radio 数字无线中继DTS Data Transmission System 数据传输系统DTS Digital Termination Service 数字终端业务DTS Digital Transmission System 数字传输系统DTSA Dynamic Time Slot Allocation 动态时隙分配DTSWCH Digital Trunk SWitCH 数字中继交换DTT Data Transmission Technique 数据传输技术DTU Data Terminal Unit 数据终端单元DTV DeskTop Video 桌面视频DTV Digital TeleVision 数字电视DU Dispersion-Unshifted 非色散位移光纤DUA Directory User Agent 目录用户代理DUI Data Unit Interface 数据单元接口DUP Data User Part 数据用户部分DUP Destination User Prompter 目的用户提示器DV Desktop Video-conference 桌面型视频会议系统DV Digital Video 数字视频DV-MCI Digital Video-Media Control Interface 数字视频媒体控制接口DVB Digital Video Broadcast 数字视频广播DVC Desktop Video Conference 桌面型视频会议系统DVC Digital Video Compression 数字视频压缩DVC Digital Video Controller 数字视频控制器DVD Digital Versatile Disc 数字通用光盘DVD Digital Video Disk 数字影碟DVDS Digital Video Display System 数字视频显示系统DVE Digital Video Effect 数字视频效果DVHT Digital Video Home Terminal 数字电视家庭终端DVI Digital Video Interactive 交互式数字视频DVM Data Voice Multiplexer 数据语音复用器DVMP Data Voice MultiPlex 数据话音多路复用DVN Digital Video Network 数字视频网DVO Data Voice Outlet 数据语音引线(出口)DVP Deterministic Virtual Path 确定性虚通路DVS Desktop Video Studio 桌面视频演播室DVS Digital Video System 数字视频系统DVVI Data Voice Video Integration 数据话音视频集成DVXS Digital Visual eXchange Service 数字可视交换业务DW Data Warehouse 数据仓库DWDM Dense Wavelength Division Multiplexing 密集波分复用DWMS Data Warehouse Management System 数据仓库管理系统DWMT Discrete Wavelet Multi-T one 离散小波多音DWRR Dynamic Weighted Round-Robin 动态加权循环法DWS Dialable Wideband Service 可拨号的宽带业务DWT Discrete Wavelet Transform 离散小波变换DXC Digital CrosS Connection 数字交叉连接DXC Digital CrosS Connect system 数字交叉连接系统DXI Data eXchange Interface 数据交换接口。
第六章常用术语缩写1.C-FTTH（Cable-FTTH，有线电视网络光纤到户）2.3.4.5.6.CPE（Customer Premise Equipment，客户终端设计）7.AES（Advanced Encryption Standard，高级加密标准）8.DES（Data Encryption Algorithm，数据加密算法）9.FTTX（Fiber-To-The-X，光纤接入）10.P2P（Point to Point，点对点形式拓扑）11.FTTH（Fiber To The Home，光纤到户）12.P2MP（Point to Multi-Point，点对多点形式拓扑）13.FTTP（Fiber To The Premise，光纤到用户所在地）14.FTTZ（Fiber To The Zone，光纤到小区）15.AON （Active Optical Network，有源光网络）16.TDM（Time Division Multiplexing，时分复用）17.MAC（Media Access Control，媒体访问控制）18.GPON（Gigabit Passive Optical Network，千兆无源光网络）19.20.21.ODN（Optical Distribution Network，光配线网）22.DBA（Dynamic Bandwidth Allocation，动态带宽分配）23.WRED（Weighted Random Early Detection，加权随机先期检测）24.LLID（Logical Link Identifier，逻辑链路标记）25.TDMA（Time Division Multiple Access，时分多址接入技术）26.MDI（Medium Dependent Interface，媒质相关接口）27.PMD（Physical Medium Dependent，物理媒质相关子层）28.PMA（Physical Medium Attachment，物理媒质附加子层）29.PCS（Physical Coding Sublayer，物理编码子层）30.GMII（Gigabit Media Independent Interface，吉比特媒质无关接口）31.RS（Reconciliation Sublayer，协调子层）32.LLC（Logical Link Control，逻辑链路控制子层）33.MPCP（Multi-Point Control Protocol多点控制协议）34.APC（Automatic Power Control自动功率控制）35.OBN（Optical Broadcast Network，光广播电视网络）36.OIN（Optical IP Network光IP数据网络）37.38.39.PLC（Power Line Communication，电力线通信）40.CLT（Coax Line Terminal，同轴电缆线路头端）U（Coax Network Unit，同轴网络单元）42.MIMO（Multiple-Input Multiple-Output，多入多出）43.OFDM（Orthogonal Frequency Division Multiplexing，正交频分复用）44.CSMA/CA（Carrier Sense Multiple Access with Collision Avoidance，载波侦听多点接入/冲突避免）45.Home Plug（Home Plug PowerLine Alliance，家庭插座电力线联盟）46.HomePNA（Home Phoneline Networking Alliance，家庭电话线网络联盟）47.MoCA（Multimedia over Coax Alliance，同轴电缆多媒体联盟）48.TDD（Time Division Duplex，时分双工）49.HiNOC（High Performance Network Over Coax，基于同轴的高性能网络）50.NMS（Network Management System，网络管理系统）51.DECO（Data transmission with EPON MAC and Coded OFDM，基于EPON媒体介入控制和编码正交频分复用的数据传输技术）52.ECAN（Ethernet Over Caox Access Network，基于同轴电缆接入网的以太网）53.EPOC（Ethernet Passive network Over Coax，基于同轴电缆的无源以太网络）54.SNMP（Simple Network Management Protocol，简单网络管理协议）。
引用本文：朱悦,何荣希，陈晓静.FiWi网络低延迟分布式动态带宽分配算法［J］.光通信技术，2020,44(7):40-46.FiWi网络低延迟分布式动态带宽分配算法朱悦何荣希"，陈晓静(1.大连海事大学信息科学技术学院，辽宁大连116026&2.大连科技学院，辽宁大连116052)摘要:针对光纤无线网络已有动态带宽分配算法时延较大、信道利用率较低的问题，提出一种低延迟分布式动态带宽分配算法.该算法每个轮询周期包含无线请求报告和上行数据传输两个子周期，可在无线信道和上行信道并行进行.无线请求报告子周期采用双向轮询方式，而且节点回传Gate帧与上传数据也并行进行.仿真结果表明：该算法可降低数据包平均时延和节点平均队列长度，提高上行信道利用率.关键词：光纤无线网络;动态带宽分配;分布式;双向轮询；并行中图分类号：TN929.il文献标志码：A文章编号：1002-5561(2020)07-0040-07D01：10.13921/ki.issn1002-5561.2020.07.010开放科学(资源服务)标识码！OSID)：詠拿羅回謎磁回Low latency distributed dynamicbandwidth allocation algorithm in FiWi networksZHU Yue1,HE Rongxi1*,CHEN Xiaojing1-2(1.College of Information Science and Technology,Dalian Maritime University,Dalian Liaoning116026,China;2.Dalian University of Science and Technology,Dalian Liaoning116052,China#Abstract:In order to solve the problems of large delay and low channel utilization of existing dynamic bandwidth allocation (DBA)algorithms in fiber-wireless(FiWi)networks,a low latency distributed DBA(LLD-DBA)algorithm is proposed.Each polling cycle of LLD-DBA consists of two sub-cycles of wireless reporting and upstream data transmission,which can be carried out in parallel on the wireless channel and the upstream channel,respectively.The bidirectional polling is adopted in the sub-cycle of wireless reporting,and each node can transmit the Gate frame to its neighbor node and upload its data in parallel.Extensive simulation results show that compared with the existing algorithms,the proposed algorithm can reduce the average packet delay, average queue length of nodes,and improve the utilization of upstream channel.Key words:fiber-wireless networks;dynamic bandwidth allocation;distributed;bidirectional polling;parallel0引言典型的光纤无线(FiWi)网络由后端的无源光网络(P0N)和前端的无线网络(如WiFi、Wimax、蜂窝网络等)构成，其中P0N的光网络单元(0NU)可与无线网络的基站(BS)或接入点(AP)集成在一起，形成0NU-BS或0NU-AP节点为有线或无线用户提供宽带接入收稿日期：2019-12-31*基金项目：国家自然科学基金项目(61371091(61801074)资助；大连市科技创新基金项目(2019J11CY015)资助*作者简介：朱悦(1995—),女,辽宁大连人，硕士生，2017年获得大连海事大学电子信息工程工学学士学位，现就读于大连海事大学信息科学技术学院信息与通信工程专业，主要从事光纤无线网络动态带宽分配算法的研究*@通信作者：何荣希(Email:************.cn)*服务：1-2＜。
Abstract: In the competitive broadband access environment, providing access to “triple play” services (voice, video, and high-speed data) is an important way for both telephone and CATV network providers to increase their revenue. Pas-sive Optical Networks (PONs) are a cost-effective, flexible, and future-proof medium for providing triple play services. The 1 Gbit/s IEEE 802.3ah Ethernet PON (EPON) and ITU-T G.984 2.5 Gbit/ s PON (GPON) are currently being deployed for triple play service access. However, high defini-tion switched digital video service such as IPTV will require more bandwidth. This paper provides a tutorial overview of the IEEE 802.3av 10Gbit/s Ethernet PON (10G EPON) standard, including the ways in which it differs from EPON.i. introduCtionPassive optical networks (PONs) have become popular as a way to reduce the number of optical transceivers and fibers in access networks by mov-ing the splitters closer to the subscriber[2]. The most popular PON protocols being deployed today are the IEEE 802.3ah Ethernet PON (EPON) and ITU-T Gigabit PON (GPON)[3]. The emerging IEEE 802.3av 10G EPON [1] standard is the latest and highest speed PON protocol using time divi-sion multiple access (TDMA). At least two broad factors are already at work to push a migration to 10G EPON. The first is the increased bandwidth of home networks. Both the IEEE 802.11 wire-less networks and the wireline home networks are increasing in capacity beyond 100 Mbit/s. Part of this factor is the decreasing cost and increasing availability of 802.11n and 1 Gbit/s Ethernet inter-faces on new personal computers. The other fac-tor is the expectation of increased customer desire for more on-demand digital video delivery. While the current generation of PON systems can satisfy some of this demand, the migration to HD video will require higher speed PONs.After a brief introduction to the concepts of TDMA PON protocols, this paper describes the 10G EPON protocol and how it differs from the EPON protocol.ii. introduCtion to PonAs illustrated in Figure 1, a PON system uses a single optical transceiver at the optical line termi-nal (OLT) to serve multiple subscribers over a fiber tree/bus network constructed with passive optical signal splitters. The 10G EPON protocol uses time论文集锦division multiple access (TDMA) in which the OLT broadcasts the downstream data and synchro-nization information to all optical network units (ONUs). The ONUs extract their downstream data based on packet address information. In the upstream direction, the OLT assigns (grants) each ONU time slots in which to transmit its upstream data.A guard time is required between the upstream burst transmissions of different ONUs so that their transmissions don’t overlap at the OLU receiver. Note that the ONUs must turn their lasers off when they are not transmitting in order to prevent spon-taneous emission noise from ONUs closer to the OLT from interfering with data transmissions from ONUs further from the OLT. In order to minimize this guard time, the OLT uses a protocol to deter-mine the round trip delay time between itself and each ONU and takes it into account when assign-ing the ONU upstream transmission times.iii. iEEE 802.3av 10Gbit/s EthErnEt-basEd Pon (10G EPon)10G EPON shares much of its protocol with EPON. A combination of coarse wave division multiplexing (CWDM) and time division multi-plexing (TDM) is used in order to allow EPON and 10G EPON systems to co-exist on the same PON. As with EPON, 10G EPON relies on V oIP for car-rying voice traffic and circuit emulation service (CES) for carrying other TDM client signals.3.1 10G EPON Physical LayerThe downstream data rate of 10G EPON is 10 Gbit/s. Both 1 Gbit/s and 10 Gbit/s rates are sup-ported in the upstream direction. The 64B/66B block line code is used for all of the 10Gbit/s sig-nals with a resulting signal line rate of 10.3125 Gbit/s. The 1 Gbit/s upstream uses the same 8B/10B block line code as EPON, giving a line rate of 1.25 Gbit/s.The downstream and upstream data is trans-mitted over a single PON fiber, using WDM to separate the upstream and downstream signals. The wavelengths used by the different upstream and downstream signals are shown in Figure 2. Since there are many ONUs on the PON and only a single OLT, the wavelength bands were chosen to allow using less expensive lasers at the ONUs. Lasers that operate in the 1270nm and 1310nm re-gions are less expensive than those operating in the 1500-1600nm range due both to the technology re-quired for their fabrication and the relative market volumes for the lasers.For 1 Gbit/s upstream operation, 10G EPON uses the same 1310nm wavelength as the EPON upstream signal. This allows the OLT to use the same receiver for all 1 Gbit/s signals. The 10 Gbit/ s upstream signals use a separate wavelength band, however since it overlaps with the 1 Gbit/s upstream wavelength band, the upstream transmis-sion is time shared between 1 and 10 Gbit/s ONUs.A dynamic bandwidth allocation (DBA) algorithm allocates the bandwidth of the upstream signal be-tween the EPON and 10G EPON ONUs.The advantages to allowing 10G EPON to oper-ate over the same PON optical distribution network that is already being used for EPON include: Allowing customers to use the most cost-effec-tive ONU for the desired serviceAllowing a network to migrate from EPON to 10G EPON by upgrading the OLT then migrating the ONUs as neededContinued operation of the existing network and services during the upgrade of the networkFigure 3. illustrates a network where an OLT supports a mix of EPON ONUs, ONUs with 10Gbit/s downstream and 1Gbit/s upstream, and ONUs with 10Gbit/s upstream and downstream. For convenience, the wavelength color key in Figure 3. is consistent with the key for Figure 2. Note that WDM is used to separate the 1Gbit/s and 10Gbit/s traffic in the downstream direction, and a combination of WDM and TDM is used in the upstream direction. The ONU discovery and other protocol extensions to support the co-existence of EPON and 10G EPON ONUs are discussed in the appropriate sections below.As its reference for the optical link loss budgets, the 802.3av specification uses a split ratio of either 1:16 (i.e., 16 ONUs on a single PON connecting to one OLT interface) or 1:32. In practice, larger split ratios such as 1:64 or 1:128 can be used if the oth-er optical losses (e.g., the length of the fiber) are constrained to offset the additional 3dB loss that is incurred when the split ratio is doubled.(Note that the practical limits on the split ratio are a function of the combination of the optical parameters, such as loss budget, and the desired per-ONU band-width.) All of the interfaces are specified to oper-ate at an uncorrected bit error rate no worse than (BER) 10-3. After FEC correction, the bit error rate will be no worse than 10-12. The nomenclature adopted to identify the different optical interface options may be summarized as follows:PRX interfaces use 10 Gbit/s downstream and 1 Gbit/s upstream transmissionPR interfaces use 10 Gbit/s for both downstream and upstream transmissionPR-D n and PRX-D n (n = 10, 20, 30) refer to the OLT optical interface specificationPR-U n and PRX-U n (n = 10, 20, 30) refer to the ONU optical interface specificationPR10 and PRX10 specifies an optical channel insertion loss of ≤20 dB for ≥10 km reach with 1:16split ratioPR20 and PRX20 specifies an optical channel insertion loss of ≤24 dB for ≥20 km reach with a 1:16 split ratio or ≥10 km reach with a 1:32 splitratioPR30 and PRX30 specifies an optical channel insertion loss of ≤29 dB for ≥20 km reach with a 1:32 split ratioAs with EPON, the 1550-1560nm-wavelength band is reserved for downstream video transmis-sion.Following the same approach as EPON, the up-stream burst timing is relaxed for 10G EPON in order to allow using existing off-the-shelf compo-nents. The standard has mechanisms to allow for future tighter timing to be implemented with better components for increased bandwidth efficiency.论文集锦Dual-rate operationDual-rate operation refers to an OLT that simul-taneously receives upstream signals from ONUs using 1 Gbit/s and 10 Gbit/s rates. The received 1 Gbit/s and 10 Gbit/s streams can either be sepa-rated in the optical domain or electrical domain. Unfortunately, since both signals time-share the same upstream wavelength band, it is not pos-sible to use WDM filters to isolate them in the optical domain. Separating the signals in the opti-cal domain involves using a 1:2 optical splitter. Each of the two splitter outputs goes to its own photodetector followed by a receiver with a filter optimized for its signal rate in order to maximize the receiver’s sensitivity. The drawback with this approach is the roughly 3dB additional optical loss introduced by the 1:2 optical splitter. If this ad-ditional loss cannot be tolerated, a low-gain optical amplifier must be used in the receiver. Splitting in the electrical domain allows using a single photo-detector and introduces no additional optical signal loss. There are different approaches to recovering the 1 and 10 Gbit/s signals in the electrical domain with tradeoffs between performance and complex-ity.3.2 Signal formats and Media Access Control (MAC) protocol3.2.1 Signal formatsWith the exception of the added forward error cor-rection (FEC) coding, the downstream signal is simply a stream of Ethernet frames and Idle char-acters, as with a point-to-point 10 Gbit/s Ethernet signal. The upstream signal is also essentially an Ethernet stream except that, as discussed above, a TDMA burst format is used. The upstream signal also uses FEC.The format of an upstream burst is illustrated in Figure 4. The synchronization patterns at the beginning of an upstream transmission burst allow the OLT to synchronize its receiver to new burst from an ONU. The Burst Delimiter pattern is used by the OLT to determine the start of 66B block transmission and the FEC codeword alignment. The 66-bit value of the Burst Delimiter is 0x 4 97 BA C4 69 F0 4C 88 FD (which results in a trans-mission bit sequence of 10 11101001 01011101 00100011 10010110 00001111 00110010 00010001 10111111). The FEC codeword align-ment can be achieved in the presence of transmis-sion errors. This burst delimiter is followed by two 66-bit blocks containing Idle characters. These Idle characters allow the OLT to synchronize its descrambler and delineate the start of the actual data frame. The first two blocks of Idle characters are included in the initial FEC codeword.The preamble and start of frame delimiter (SFD) are modified for EPON and 10G EPON from their normal values for Ethernet. Specifically, the preamble bytes are replaced by the transmitting MAC’s MODE and LLID variables. While the Ethernet 8-character preamble/SFD consists of/ S/, 0x55, 0x55, 0x55, 0x55, 0x55, 0x55, and 0xd5, the EPON and 10G EPON preamble/SFD consists of 0x55, 0x55, SLD, 0x55, 0x55, 2-octet LLID, and CRC-8. The SLD is the Start of LLID Delim-iter, and has the value 0xd5. The LLID is the two-octet logical_link_id field that uniquely identifies the ONU MAC. The MSB of the two octets that contain the LLID is the MODE indication bit. As discussed in section 3.4, the LLID is assigned to the ONU by the OLT during the registration phase of the discovery process. The CRC-8 covers the SLD through the LLID octets, and uses the genera-tor polynomial x8 +x2 + x + 1.The upstream transmission ends with a burst terminator pattern comprised of three 66-bit blocks of alternating zeros and ones (1010 … 10) after the last FEC codeword of the burst. The ONU turns off its laser at the beginning of the burst terminator pattern, which insures that it will be completely off by the end of the burst.Each ONU has one unique Logical Link Identi-fier (LLID) that the OLT associates to the ONU for uni-cast traffic. In other words, these MAC instances are used to emulate a point-to-point con-nection between an ONU and the OLT over the PON. In addition, the OLT has two Single Copy Broadcast (SCB) MAC instances that are used asan efficient mechanism to broadcast downstream traffic to the ONUs. Such a broadcast is used for broadcast data or for when the OLT must commu-nicate with unregistered ONUs. In the upstream direction, an SCB MAC is only used for client registration. The LLID value of 7F-FF is associ-ated with the SCB MAC for 1 Gbit/s downstream operation and the LLID value of 7F-FE is associ-ated with the SCB MAC for 10 Gbit/s downstream operation. An ONU can use higher layer network-ing processing, such as VLAN filtering and IGMP snooping, to narrow the amount of received multi-cast traffic that is passed to applications. It is pos-sible that these higher layers may require addition multicast MAC instances at the OLT, in which case an OLT can have more MACs than two plus the number of ONUs.Multi-Point Control Protocol PDUs (MPCPDUs) are control frames used by the ONUs to make their requests for bandwidth, and by the OLT to assign it. As illustrated in Figure 5, the MPCPDU1 frame is a basic 802.3 MAC control frame containing a 4-byte timestamp and a 40-byte field filled with data and padding as needed. MPCPDU messages are also used for the discovery and ranging proc-esses, as discussed in sections 4.3 and 4.4. MPCP-DUs are layered below the data interface, and have higher priority than any data packet. This ensures that the bandwidth requests and grants are sent in a timely manner.3.2.2 MAC-layer control protocol The 10G EPON MAC-layer control protocol is based on the protocol for EPON and includes enhancements for management of 10G FEC and inter-burst overhead. This MAC protocol oper-ates on the basis of the ONUs informing the OLT of their upstream bandwidth requirements, and the OLT scheduling and granting bandwidth to the ONUs to transmit their upstream data. The details of the MAC protocol are described in this section and are illustrated in Figure 6 with the downstream and upstream data flows.3.2.3 GATE messages for upstream bandwidth论文集锦grantsThe OLT grants bandwidth to an ONU in the GATE MPCPDU message that is transmitted downstream. Gating is the function that controls when the ONUs are allowed to transmit upstream data. The Gating function relies on a local ONU timer that is synchronized to the OLT timer. (See the ranging protocol description in section 3.5 for a further discussion of the timers.) The GATE mes-sage specifies the ONU upstream start time and transmission length. The bandwidth grants from OLT are always made for at least 1024 time quanta into the future so that the ONU has time to process the GATE message and be ready to transmit. An ONU turns its laser on when the local time equalsthe start time specified in the GATE message. The length field gives the length of time that the ONU is allowed to transmit its burst. The time windowis specified with respect to the number of periods of the ONU’s local clock. The start time is a 32-bit number (the same length as the local timer counter), and the length is a 16-bit number. The OLT includes the time required to turn the ONU laser on and off and the time to send the upstream synchronization patterns when it assigns the grant time.The OLT sends GATE messages to each ONU periodically so that they can report their upstream bandwidth needs. The first (left-most) grant in Figure 6 is an example of such a periodic grant. The GATE MPCPDU is illustrated in Figure 5. The ONUs have watchdog timers that are reset whenever a GATE message is received. Note that a flag in the GATE message can be used to force the ONU to respond with the REPORT MPCPDU described below.The number of upstream bandwidth grants in a GATE message can range from 0-4. As discussed in section 4.3, the ONU advertises the number of outstanding grants it can accept during the discov-ery process. A GATE message with no grants is used as a keep-alive for the ONU timeout counters and to communicate the timestamp information. The use of multiple grants in a single GATE mes-sage is illustrated with the first payload transmis-sion from ONUx in Figure 6. For example, the different grants could correspond to different prior-ity queues at the ONU. In practice, however, thisadds considerable complexity to the OLT band-width assignment process. Sending a single grant in the GATE message gives much finer resolution and faster response for the upstream bandwidthassignments, and has only a small impact on thedownstream overhead bandwidth. The preferred approach, especially for per-flow DBA, is for the OLT to send each ONU a single grant in eachGATE message to service its bandwidth requestsand let the ONU decide which data should be sentin that upstream grant.The “Sync Time” field in the GATE MPCPDU is a report from the OLT to communicate theamount of time it needs at the beginning of theupstream transmission burst to synchronize its re-ceiver to the new burst. As illustrated in Figure 4,each burst begins with a synchronization pattern,followed by a Burst Delimiter pattern, followed bytwo blocks of Idle characters. The ONU transmitsthe 66-bit synchronization pattern repeatedly andthen transmits the Burst Delimiter so that the dura-tion of the entire sequence is the same as the SyncTime requested by the OLT.3.2.4 REPORT messages for upstream bandwidth requestsThe ONUs communicate their upstream bandwidthrequirements by sending REPORT MPCPDU mes-sages. The OLT grants the upstream bandwidth forthese REPORT messages in its GATE messages.In addition to the timestamp, the REPORT messageconsists of a summary of its requests for upstream bandwidth, and the specific amount of bandwidth it needs. Like EPON, 10G EPON supports the eight queue priority levels defined in IEEE 802.1Q. The summary field of the REPORT message indicates how many and which, if any, of these queues havedata to send. The summary is followed by binary numbers to indicate the specific number of bits to be transmitted from each queue. The bit count is a 16-bit number, and includes Inter-Packet Gap (IPG) characters. Unlike EPON, the bandwidth value carried by the 10G EPON REPORT does not include burst overhead or FEC overhead.Each ONU sends REPORT messages periodi-cally, even if it has no data waiting for transmis-sion, in order to reset a watchdog timer at the OLT. If the watchdog timer expires, the OLT deregisters that ONU from the network.3.3 FEC (Forward Error Correction)FEC allows a link to operate with a higher bit error rate at the receiver. Consequently, FEC effectively increases the optical link budget, which in turn allows increased distance or split ratios. FEC be-comes increasingly important as bit rate increases. For this reason, FEC is mandatory in 10G EPON. Additionally, the 10G EPON FEC differs in two ways from EPON. First, 10G EPON uses a more powerful RS(255, 223) code for error correction of 16 symbols rather than the 8 symbols that can be corrected with the optional RS(255,239) code specified for EPON.2 Second, the 10G EPON FEC is applied to fixed-length sequences of stream-ing data rather than Ethernet frames as illustrated in Figure 7. Figure 7 illustrates the downstream transmission direction, which is a continuous stream of FEC codewords that includes the Ether-net frames and all inter-packet information such as IPG and Ordered Set data. The upstream transmis-sion is similar except, as illustrated in Figure 4, the first FEC codeword of an upstream burst is aligned with the beginning of the burst in order to allow the OLT FEC decoder immediate codeword syn-chronization for each burst.One of the challenges in adding FEC to the论文集锦10GE PON stream is extending the 64B/66B block code format so that a 10GbE receiver can receive and synchronize to the stream that now includes FEC parity data. The method used is illustrated in Figure 8. Each FEC codeword covers a group of 27 64B/66B blocks. The first step of FEC encod -ing is removing the first flag bit of the 64B/66B block.3 The resulting 27x65 = 1755-bit block is padded with 29 leading zeros to get a total of 1784 bits (223 bytes). The RS(255,223) encoding pro-duces 32 parity bytes. In the final stage, the zero pad bits are removed, the original 27 64B/66B blocks are restored, and the parity bytes are con-verted into a sequence of 64B/66B blocks for transmission. Specifically, the 32 FEC parity bytes are treated a four groups of 64 bits. Each of these 64-bit parity groups is then given a pair of leading header bits in order to create 64B/66B blocks. In order to create a recognizable header pattern, the header bits for the four parity blocks are 00, 11, 11, and 00, respectively. The string of 31 64B/66B characters is then transmitted.The receiver can then synchronize to the 64B/66B character stream and extract the original data through the reverse process, performing error correction as it decodes the FEC blocks. 3.4 ONU discovery and activationThe message handshake is illustrated in Figure 9. The OLT periodically opens a Discovery Window in order to allow new ONUs to announce them-selves. This period is implementation dependent. The OLT opens the Window by transmitting a dis-covery GATE message, which includes the length of the Window and its start time. A discovery GATE MPCPDU includes a Discovery information field that communicates to the ONUs whether the OLT is capable of receiving 1Gbit/s upstream sig-nals, capable of receiving 10Gbit/s upstream sig-nals, and whether the discovery window is being opened is for 1Gbit/s or 10Gbit/s upstream signals from the ONUs.The unregistered ONUs respond to the discov-ery GATE message by transmitting a REGISTER_REQ message. The REGISTER_REQ messageincludes the ONU’s MAC address and the number of outstanding grants that it can accept. (See sec-tion 3.2.2 regarding multiple grants.) The REG-ISTER_REQ has been expanded to include fields for Laser On time and Laser Off time to specify the time required by the ONU to turn its laser on and off. A contention algorithm is used in order to minimize the chance of collision when multiple ONUs are attempting to register during the same Discover Time Window. The contention algorithm operates by having each ONU delay its transmis-sion by a random time relative to the beginning of the Discover Window. Note that the upper bound requirement on this hold-off time is that it must be short enough that the ONU can transmit its entire REGISTER_REQ before the end of the Discovery Window.When the OLT receives the REGISTER_REQ, it assigns an LLID to the ONU, bonding the LLID to the ONU’s MAC address. The OLT then sends a REGISTER message to the ONU in order to communicate the ONU’s LLID and the required OLT synchronization time, to echo the maximum number of pending grants that the ONU can ac-cept, and to echo the ONU LaserOn and Lase-rOff time fields. The synchronization time is the amount of time the OLT will require in order to reliably synchronize to the ONU’s upstream trans-mission burst. The synchronization time is speci-fied in multiples of 66-bit data patterns that the ONU sends at the beginning of the burst.After the ONU has processed the Register mes-sage, it sends a Register_ACK message to the OLT in response to a standard GATE message from the OLT.Note that the Discovery GATE, REGISTER_ REQ, and REGISTER messages are sent on the broadcast channel since ONU doesn’t know its LLID until it receives the REGISTER message. After the ONU receives its LLID, the remaining GATE and REGISTER_ACK messages are sent on the unicast channel.Mechanisms exist in the protocol to deregister an ONU (e.g., if a watchdog timer expires) and re-register.3.5 Ranging mechanismThe ranging mechanism makes use of local clocks that are maintained by the OLT and each ONU. A counter has 32 bits, and is incremented once every 16 ns.The OLT counter is the PON master. When the OLT transmits a MPCPDU message, it loads its current counter value into the message’s 32-bit timestamp field. When the ONU receives a MPCPDU, it resets its own local counter to the value contained in the MPCPDU timestamp field. When the ONU sends a MPCPDU to the OLT, the ONU loads its updated counter value into the timestamp field. The OLT then compares the offset between its current count and the value it receives in the MPCPDU timestamp field, with the differ-ence being the round trip time (RTT). The RTT is then used to establish the ONU’s range, which is taken into account when the OLT assigns the start times for upstream bandwidth grants.Some drift may occur in the RTT over time. When the drift exceeds a specified threshold, a timestamp drift error condition is declared. Either论文集锦the ONU or OLT can detect this condition as an offset between the expected value received in the MPCPDU and the one actually received.3.6 EPON OAMEthernet link OAM was developed as part of the same IEEE 802.3ah project that developed EPON. Several Ethernet frames were defined to communi-cate the link OAM information.3.7 Dynamic bandwidth allocationWith Dynamic Bandwidth Allocation (DBA), the OLT assigns the bandwidth to the different ONUs based on the data they have to send rather than a static allocation per ONU. As described above, the ONU REPORT messages inform the OLT of their current bandwidth needs. Their bandwidth re-quests are reported in terms of the number of char-acters they have in the different priority queues awaiting upstream transmission. The OLT can also take into account the service level agreements (SLAs) that have been specified for the service flows associated with an ONU. For example, an ONU with an active V oIP service will need a fixed amount of bandwidth on a regular basis. Conse-quently, the ONU does not need to waste upstream bandwidth reporting bandwidth requests for this service flow. As another example, if the OLT re-ceives upstream bandwidth requests from multiple ONUs, it can grant more bandwidth to ONUs that have been recently consistently requesting more bandwidth than to ONUs that have had few recent requests. In this example, the DBA algorithm needs to insure that nodes with fewer bandwidth requests don’t become starved or encounter high latency while the ONUs with more bandwidth re-quests are serviced.EPON DBA has the flexibility to customize EPON network behavior to meet various carrier needs. The flexible nature of the EPON DBA is defined in both EPON standards (1G & 10G) and allows quick adaptation to possible carrier chal-lenges, making the EPON infrastructure compli-ant with the ever growing, ever changing carrier's requirements. It is possible to map both user and service flows into specific containers that are managed by the DBA and provide the QoS that is needed for every customer and service. Two straightforward adjustable parameters related to EPON DBA are latency and total system perform-ance (upstream bandwidth utilization). An exam-ple of this is the Service DBA algorithm used in PMC’s EPON OLT devices.One benefit of the 10GEPON system is the ability to overcome system bottlenecks via adjust-ments in the EPON DBA algorithm. The DBA cy-cle length and bandwidth allocation per ONU can be adjusted so that the total OLT upstream trans-mission going into the switch will be "smoother", less bursty in nature, allowing carriers to overcome blocking elements in their network topology (e.g. assigning more bandwidth to the OLT ports than the uplink ports in the switch connected to the OLT to save CAPEX).iv. summary of EPon and 10G EPon fEaturEsTable 1 gives a summary of the key features of EPON and 10G EPON.v. ConClusionsDue to its very high bandwidth capability, fiber is the most flexible medium for broadband serv-ice delivery to the home. After years of being a promising “next generation” technology, FTTH has finally become an economically viable op-tion for providing residential triple-play services. The various technical and operational hurdles that have slowed large-scale deployment of FTTH have largely been resolved.PON is the most cost-effective approach to pro-viding FTTH. By providing a highly flexible plat-form for different services, and by eliminating the active electronics from the access plant, PON pro-vides carriers with substantial ongoing OAM sav-。
电信主管部门,电信管理局 telecommunications administration 电信总局 directorate-general of telecommunications, dgt 电压、电阻和电容等参量 parameter(voltage, resistance and capacitance) vrc 电压表 voltmeter 电压调整器 voltage regulator 电压告警范围 voltage alarm range 电压驻波⽐ voltage standing wave ratio vswr 电影点播 movie on demand mod 电涌吸收器,过压吸收器 surge absorber 电源 power supply 电源插框 power plug-in shelf 电源存储器 electric power storage eps 电源断,切断电源,电源中断,掉电 power-off 电源分配显⽰板 power distribution display card 电源监控 power supply monitoring 电源接地power ground 电源馈线 power feeder 电源连接器 power connector 电源模块 power module 电源软线 power cord 电源系统power system 电⽀路 electric tributary etp 电⽀路插槽 electric tributary pdh etp1s 电⽀路接⼝单元 electrical tributary interface units 电⽀路转换器 electric tributary transformer etp1t 电⼦⽩板 electronic white board 电⼦表格 electronic form 电⼦出版electronic publishing 电⼦交换系统 electronic switching system ess 电⼦期刊 e-journal 电⼦签名 electronic signature 电⼦商务 e-commerce ec 电⼦数据互换 electronic data interchange edi 电⼦现⾦ electronic cash 电⼦信息互换系统 electronic information exchange system eies 电⼦邮件 e-mail, electronic-mail 电⼦杂志 electronic magazine 电⼦资⾦转帐 electronic funds transfer eft 电阻器 resistor 垫⽚ gasket 吊环螺栓 eyebolt 吊扣 suspension clasp 调测配件 fittings for commissioning 调测整机 debugging integrated equipment 调度程序 scheduler 调度通信系统 dispatch communication system 调幅 amplitude modulation am 调试 debug 调停功能 mediation functions 调制/解调 modulator/demodulator modulate/demodulate modem 调制解调器 modem 掉电 power failure 叠加 overlay network ron 叠加写盘 overlap writing 顶侧板 top-side door 顶盖、底盖、盖板 top cover, bottom cover, and cover board 顶门板 top door 顶⾯板 top panel 定（⽅）向增益 directive gain 定标频率beacon frequency 定界和定位 delimiter and localizationdelimiting and locating 定⼒矩扳⼿ torque wrench 定时 timing 定时参考信号 timing reference signal 定时传输管理单元 timing/transmission and management unit tmu 定时调整控制环 time adjustment control loop 定时供给单元 synchronization supply unit ssu 定时器 timer 定时器 timer 定时时长 timing length 定时提前量 timing advance ta 定时信号供给系统 timing system 定位螺钉 positioning screw, set screw 定位⽚,衬垫 spacer 定向天线 directional antenna 定向⽆线电 directional radio 定向⼩区 directional cell 定向重试 directed retry 定制的,定做的customized, tailored 动态带宽分配 dynamic bandwidth allocation dba 动态⾮等级路由选择 dynamic non-hierarchical routing 动态服务器页⾯技术 active server pages asp 动态配置 dynamic configuration 动态随机存取存储器 dynamic random access memory dram 动态信道分配 dynamic channel allocation dca 动态信令跟踪 dynamic signaling tracing dst 动态主机配置协议dynamic host configuration protocol dhcp 动作指⽰符 action indicator ai 抖动 jitter 抖动传递特性 jitter transfer function 抖动容限 jitter toleration 读取值 read-out values 读中继属性失败 fail to read trunk attribute 独⽴的,⾃含的,已配套的,设备齐全的 self-contained 独⽴局，独⽴交换局 standalone exchange 独⽴控制信道 standalone dedicated control channel sdcch 独⽴式standalone 独⽴同步装置 standalone synchronous equipment sase 独⽴系统 stand-alone system 独⽴于业务的构件 service independent building block sib 独⽴专⽤控制信道 stand-alone dedicated control channel sdcch 独⽯电容 leaded multilayer ceramic capacitor 镀铬 chromium electroplating 镀⾦ gild electroplating 镀镍 nickel electroplating 镀铜 copper electroplating 镀锡 tin electroplating 镀锌 zinc electroplating 镀锌板 galvanized sheet 镀银 silver electroplating 端到端 end-to-end ete 端局end office 端⼝ port 短距 short range, short haul 短路光纤 short-circuiting optical fiber 短消息服务（业务） short message service sms 短消息关⼝msc short message service gateway msc sms-gsmc 短消息关⼝互连msc gateway/interworking msc g/iw msc 短消息互联msc short message service interworking msc sms-iwmsc 短消息⼩区⼴播 short message cell broadcast smscb 短消息业务 short message service sms 短消息中⼼ short message service centre sm-sc 短消息中⼼（⽤于短消息业务） short message center (used for sms) smc 段 section 段开销 section overhead soh 断环 broken ring 断开 disconnect disc 断开⽅式 disconnection mode dm 断开模式 disconnected mode dm 断开请求 disconnect request dr 断链 broken link 断纤fiber cut 断续⽐,通断⽐ break-make ratio 队列管理 queues management 对称络,平衡络 balanced network 对等计算 peer-to-peer computing 对地电压 voltage to ground 对端 opposite end 对端局 opposite office 对⽅局 opposite exchange 对告（对端告警） remote alarm 对话框 dialog box 对接 interconnection 对接传输设备 butting transmission system 对接端,相邻端abutting end 对接接头,邻接接头 connector 对象 object ob 对象集 object set 对准,校准,调整定位,排列成⾏ alignment 多波长光放⼤器 multi-wavelength optical repeater 多层介质膜滤波器型光合波器测试 test of optical multiplexer of multi-layer dielectric film filter 多程序加载 multiple program loading 多处理机系统 – 保证系统的可持续发展性 flexible multiprocessor system for reliable system evolution 多串⼝卡 multi-serial-port card 多带宽接⼊ multi-bandwidth digital access 多点控制单元 multipoint control unit mcu 多点通信业务 multipoint communication service mcs 多对⼀ several-for-one 多功能测试电路 multi-function test circuit mtt 多功能移动终端 multi-featured mobile terminal 多呼叫处理设备 multiple call processing unit 多汇接局电话multi-tandem telephone network 多径衰减 multipath fading 多路多点分配业务 multi-channel multi-point distribution service mmds 多路复⽤转换器 transmultiplexer tmux 多路⼴播 multicast 多路⾳频 multiple channel audio 多路⾳频数据接⼊板 multi-channel voice data access card 多路由保护 diverse⼀routed protection drp 多媒体 multimedia 多媒体通信设备 mutlimedia telecom equipment 多模光缆 multimode optical cable 多模光纤 multimode optical fiber 多频 multi-frequency mf 多频带 multi-band 多频互控 multi-frequency compelled mfc 多频互控单元 multiple frequency compelling unit 多频互控信令,多频制信令compelled multi-frequency signaling 多频记发器 multi-frequency coding register 多频脉冲 multi-frequency pulse mfp 多频multiple frequency network mfn 多频终端 multi-band terminal 多任务管理 multi-task management 多通道增益斜度 multi-channel gain tilt 多⽂档界⾯ multiple document interface mdi 多线程应⽤程序 multithreaded application 多信道处理单元multiple channel processing unit mcpu 多信道⾳频 multi-channel audio mcvf 多⽤户号 multiple subscriber number msn 多⽤途插座 multi-purpose socket 多余的位⽤来指⽰n-pdu的最后段 more bit used to indicate the last segment of n-pdu m 多兆⽐特交换数据服务 switched multimegabit data service smds 多址协议 multiple access protocol 多种切换算法 advanced handover algorithms (aha) aha 多重联系控制功能 multiple association control function macf 额定电压 rated voltage 额定负载 rated load 额定值 rated value 额定值 rating 恶意呼叫识别 malicious call identification mci 恶意呼叫追踪 malicious call tracing mct ⽿机earphone ⼆/四线转换电路 hybrid circuit（2-wire /4-wire conversion）⼆层建链状态 layer 2 link set-up status ⼆叉树 binary tree ⼆次拨号⾳ secondary dial tone ⼆次电源 secondary power supply ⼆次模块电源 secondary power module ⼆次群光收发板 optical transceiver card for secondary group ⼆次群光收发板（光端机） optical transceiver board for secondary group ⼆极管 diode ⼆阶交调失真 crosstalk of second order cso ⼆进制,⼆元制备,⼆进制系统 binary system ⼆进制编码⼗进制数binary coded decimal bcd ⼆纤⾃愈环 two-fiber self-healing ring ⼆相移相键控 binary phase shift keying bpsk ⼆义性,多义性,模糊含糊 ambiguity 发电机组 electric generator set 发端长话局 originating toll exchange 发端国际局 originating international exchange 发端去话篩选 originating call screening ocs 发⽅ originating party 发光⽽极管显⽰器 liquid emitting diod led 发光⼆极管 light emitting diode led 发号 send signals 发货附件 delivery accessories 发起切换的主控msc the controlling msc on which the call was originally established msc-a 发射 transmit xmt 发射机，送话器 transmitter 发射-接收装置 transmit-receive unit 发送端接收端 transmit endreceive end 发送端 transmitting end 发送光功率 transmitting optical power 发送信号眼图transmit signal eye pattern 发送序列号 transmit sequence number ptx 发信/收信机 transceiver trx 发信机 transmitter 法定的标准 de jure standards 法兰盘 ring flange 法⼈ legal person 翻译表,转换表 translation table 反病毒程序 antivirus program 反极性 polarity reversal 反射⾮敏感度 reflection insensitivity 反射损耗 reflection loss 反射增益 reflection gain 反相位 inverse phase 反向 negative 反向拆线 clear backward 反向计费 reverse charging revc 反向搜索 backward search 反向信道,反向通路backward channel 返回 return 返回点 point of return por 泛⾮电讯联盟 pan—african telecommunications union patu ⽅螺母square nut 防潮,防湿 moisture-proof 防腐蚀 corrosion-proof 防滑⼿套 slip-proof glove 防⽕墙 firewall 防静电地板 conductive floor 防静电⼿环 wrist strap 防静电⼿腕 anti-static wrist strap, wrist strap 防雷接地夹 lightning grounding clip 防蚀, 防腐蚀corrosion-proof 防⿏ rodent-resistant net 防⽔尾缆 waterproof pigtail cable 防卫措施 protective measures 访管中断supervisor call interrupt 访问，连接 access 访问地址寄存器 visitor location register vlr 访问控制 access control ac 访问码access code ac 访问⽇志 access log 访问特权，接⼊特许 access privileges 放⼤⾃辐射噪声 amplified self－emission noise ase 放号 number allocation 飞线 jump wire ⾮gprs告警标识 non-gprs alert flag ngaf ⾮标监控物料 non-bid monitor materials ⾮标准的 nonstandard ⾮电话业务 non-voice service ⾮对称数字⽤户线路 asymmetric digital subscriber line adsl ⾮法尝试计数器 wrong attempt counter wac ⾮分组终端 non-packet terminal npt ⾮服务状态 out-of-service ⾮归零码 non return to zero nrz ⾮话终端 non-voice terminal ⾮恢复式通道倒换 non-revertive path switching ⾮挥发性随机读写存储器 non-volatile random access memory nvram ⾮活动链 inactive link ⾮介⼊监控 non-intrusive monitoring ⾮⾦属件 non-metallic components ⾮⾦属件 non-metalware ⾮晶体 non-crystal ⾮平衡接⼝ non-balanced interface ⾮屏蔽双绞线，⽆屏蔽双绞线unshielded twisted-pair utp ⾮同步 asynchronous network ⾮阻塞 non-blocking 菲利浦 philips 费尔码 fire code 费率索引值charge rate index chx 费率修改索引 rate updating index rid 分/插复⽤器 add & drop multiplexer adm 分贝 decibel db 分辨率resolution 分布功能平⾯ distributed functional plane dfp 分布式 distributed 分布式数据库管理系统 distributed relational dbms drdbms 分插,分出/插⼊,分路/插⼊ add/drop d/i 分插⽅式应⽤ add/drop applications 分插复⽤器 add/drop multiplexer adm 分段和重装⼦层 segmentation and re-assembly sub-layer sar 分段类型 segment type st 分光器 optical splitter 分机 extended station, extension 分机代答 pickup 分机号 extension number 分机⽤户缺席通知 absent extension advice 分机⽤户缺席转接absent extension diversion 分机转接 extension transit 分级,系列,分层 hierarchy 分级编码 hierarchical coding 分级控制hierarchical control 分级路由选择 hierarchical routing 分级,分层,层次 hierarchical network 分级主/从同步 hierarchical master/s/slave synchronization 分集射频端⼝ diversity rf port 分检 sort 分离 detach det 分量处理 component handling cha 分流器 current divider 分路器 divider 分配（指信道分配） allocation assignment 分配点 distribution point dp 分配关系数据库管理系统 distributed relational data base management system drdms 分配呼叫路由选择 distribution call routing dcr 分配命令assignment command 分配器 distributor 分配请求 assignment request 分配失败 assignment failure 分配完成 assignment complete 分频器 frequency divider 分频锁相技术 frequency-divided phase locking technology 分散式 decentralized, distributed 分散型控制系统 distributed control system dcs 分摊计费 split charging spl 分线盒 junction box, connection box, connector box 分⽤器,分解器,分离器,去复⽤器 demultiplexer demux 分组（包）交换 packet switching 分组tmsi packet tmsi p-tmsi 分组层 packet layer procedure plp 分组处理函数 packet handler function phf 分组处理交换 packet handling switching phs 分组处理器 packet handler ph 分组电路标识码 packet circuit identity code pcic 分组定时提前控制信道 packet timing advanced control channel ptcch 分组复⽤ packet multiplexing pmx 分组⼴播控制信道 packet broadcast control channel pbcch 分组交换公⽤数据 packet switched public data network pspdn 分组交换机 packet switching exchange pse 分组接⼊允许信道 packet access grant channel pagch 分组控制单元 packet control unit pcu 分组数据信道 packet data channel pdch 分组随机接⼊信道 packet random access channel prach 分组随路控制信道 packet associated control channel pacch 分组寻呼信道 packet paging channel ppch 分组业务数据信道 packet data traffic channel pdtch 分组终端 packet terminal pt 分组装/拆packet assembling/de-assembling pad 风机盒/配电盒 fan box/power distribution box 风机盘 fan unit 风扇盒 fan box 封闭⽤户群 closed user group cug 封装 encapsulation envelop 峰值信元率 peak cell rate pcr 蜂鸣器 buzzer 蜂窝的,蜂窝电话的cellular 蜂窝分裂技术(移动通信) cell splitting technique 蜂窝分组交换 cellular packet switching cps 蜂窝基站天线, ⼩区基站天线 cell base station antenna 蜂窝基站位置, ⼩区站位置 cell base station location both (ln) 蜂窝式移动电话系统 cellular mobile telephone network 蜂窝移动电话系统 cellular mobile telephone system 蜂⾳ buzz。
收稿日期6作者简介甘 苹(),女,讲师。
文章编号:1671-7333(2008)04-0284-06高效公平的EPO N DBA 算法设计原则甘 苹(上海应用技术学院计算机科学与信息工程系,上海 200235)摘要: EPON 系统的动态带宽分配要求达到较高的带宽利用率,同时保证各类业务的服务质量及公平性。
在分析带宽利用率的影响因素的基础上,提出三条提高带宽利用率的DBA 算法设计原则:轮询周期尽可能长,消除信道闲置,避免授权时隙末的空闲。
EPON 中存在三种层次的公平性,保证用户间的公平性在我国具有重要的现实意义。
各用户获得的带宽与他们的S LA 带宽成比例应该是D BA 算法设计的一个原则。
采用两级结构的D BA 机制,为用户的各优先级业务按SLA 协议带宽比例分别授权,采用DiffServ 模型,可以实现支持QoS 的同时保证用户之间和优先级业务之间的公平性。
关键词: 以太无源光网;动态带宽分配;带宽利用率;公平性;S LA 中图分类号:TN 915 文献标识码:ADesign Principles of Fair Dynamic Bandwidth A llocationAlgorithm with H igh E fficiencyGAN Pin g(Depart ment of C o m puter Science and Information Engi neeri ng ,Shanghai Instit ute of Technol o gy ,Shanghai 200235,Chi na )Abstract :An ideal dynamic bandwi dt h allocation scheme must be efficient and fair and support s QoS.On t he base of st udying all factors determi ning li nk ut ilization ,t hree principles are proposed to boost link utiliza 2tion.They are keeping t he cycle lengt h as long as possi ble ,avoiding idle stage of t he upli nk duri ng t he DBA running ,removing unused slot remainder.Practical measures complying wit h t hese pri nciples are also pre 2sented ,such as i nterleaved t ransmission ,grant ing based on frame 2boundary 2report.Fairness in EPON can be defined as t hree types :inter 2ONU fairness ,i nter 2class fairness i n differentiated services and int er 2user fairness.Among t hem ,inter 2user fai rness is of pract ical significance i n China.A feasi ble way to guarantee bot h inter 2user fairness and int er 2class fairness i s to hierarchically grant to each class of each indi vidual sub 2scriber in proportion to service level agreement bandwidt h.Key words :et hernet passive optical networks ;dynamic bandwidt h allocation ;link efficiency ;fairness;SLA 光纤接入网(F TTx )是下一代宽带固定接入的发展方向,其主要实现方式PON 技术包括基于A TM 的B PON/APON 、以太无源光网(EPON )和吉比特无源光网(GPON )三类。
网络优化中的带宽管理与调度随着互联网的普及和发展，网络成为人们日常生活和工作中不可或缺的一部分。
无论是通信、娱乐还是信息搜索，都离不开网络的支持。
然而，随着网络用户数量的增加和网络应用的多样化，网络带宽成为了一个亟待解决的问题。
如何进行有效的带宽管理和调度，成为了网络优化中的重要议题。
一、什么是带宽管理带宽管理是指通过一系列的技术手段和策略，合理分配和调度网络带宽资源，以满足不同用户和应用的需求，并保持网络运行的稳定性和高效性。
带宽管理主要涉及到以下几个方面：1. 流量控制：通过设置流量控制策略，限制用户或应用的带宽占用，以防止某一用户或应用占用过多的带宽资源，导致其他用户访问速度变慢。
2. 拥塞控制：在网络拥塞时，带宽管理需要自动调节传输速率，避免因过量的数据传输导致网络拥堵，进一步影响网络的正常运行。
3. 优先级管理：不同用户和应用对带宽的需求不同，带宽管理需要根据优先级设置，确保重要用户和关键应用的带宽需求得到满足。
二、带宽调度的策略在网络优化中，带宽调度的策略是关键。
以下介绍几种常见的带宽调度策略：1. 公平调度（Fair Scheduling）：公平调度是一种常用的带宽调度策略，通过公平地分配带宽资源，使得各个用户或应用在带宽使用上具有均等的机会。
2. 基于优先级调度（Prioritized Scheduling）：通过为不同用户或应用设置不同的优先级，优先级调度策略可以保证重要用户或关键应用的带宽需求得到优先满足。
3. 预测调度（Predictive Scheduling）：预测调度策略通过分析用户或应用的行为模式和历史数据，预测其未来的带宽需求并相应地分配带宽资源，以提前满足需求。
三、带宽管理与调度方法除了带宽调度策略外，带宽管理与调度还涉及到具体的技术方法。
以下介绍几种常用的带宽管理与调度方法：1. 储备带宽（Bandwidth Reservation）：储备带宽是一种预先为重要用户或关键应用分配带宽资源的方法。
