ns2仿真步骤与新协议添加课件

NS2网络仿真平台李春明2008-12-08.1IntroductiontoNS-2NS2网络仿真软件概述创建基本的仿真网络一个完整的仿真例程模型说明运行和结果分析高级主题如何添加新协议.2NS-2,网络仿真器是一个具有10+年历史的科研项目成果开源、可自由分发目前主要由ISI(InformationSciencesInstitute)维护隶属DARPA+NSF项目目前，代码约~200K,手册约400页具有大量的用户主要是学术界人士是网络研究领域的事实标准主页:/nsnam/ns.3NS功能特性它是一个离散事件驱动型仿真器提供如下网络模拟组件流量模型和应用层程序Web,FTP,telnet,audio,sensornets传输层协议TCP(Reno,SACK,etc),UDP,multicast路由协议和队列管理staticrouting,DVrouting,multicast,ad-hocroutingqueueingdisciplines:drop-tail,RED,FQ链路层协议wired,wireless,satellite提供的辅助工具tracing,visualization,errormodels,etcmodifyorcreateyourownmodules.4NS2组件NS,仿真器本身NAM,可视化界面工具visualizeNS(orother)outputGUIinputsimpleNsscenarios辅助工具:trafficandtopologygenerators结果处理:simpletraceanalysis,ofteninAwk,Perl,orTclTutorial:/nsnam/ns/tutorialNSbyexample:/NS/.5NS体现架构:C++andOTCL主要采用两种语言C++实现NS仿真器的功能如数据包处理、路由算法实现等优点：运行速度快，效率高OTCL用来编写脚本，完成具体仿真[ourfocus]如建立仿真场景、参数修改配置等优点：易于编写和修改.6仿真步骤编写OTCL脚本nodes,links,trafficsources,sinks,等.确定各个对象的参数Links:queuesizes,linkspeeds,…TransportProtocols:TCPflavorandparameters(morethan30),…运行脚本，收集数据dumpeverythingtotrace,postprocessitgatherstatsduringsimulationwithinOTCLscriptmodifyNssourcecode重复多次运行NSconfidenceintervals.7创建一个基本的仿真场景CreateeventschedulerCreatenodesandlinksCreateconnectionsCreatetrafficsources/sinksEnabletracing.8CreateaBasicNSSimulationCreatetheeventschedulerCreatenodesandlinksCreateconnectionsCreatetrafficsources/sinksEnabletracing.9Step1:CreatingEventSchedulerCreateschedulersetns[newSimulator]Scheduleevent$nsat<time><event><event>:anylegitimateNs/TCLcommandsStartscheduler$nsrun.10CreateaBasicNSSimulationCreatetheeventschedulerCreatenodesandlinksCreateconnectionsCreatetrafficsources/sinksEnabletracing.11Step2:CreatingNetwork(Nodes+Links)Nodessetn0[$nsnode]setn1[$nsnode]Links:connecttogethertwonodes$nsduplex-link$n0$n1<bandwidth><delay><queue_type><delay>determinespropagationdelay<queue_type>determinesqueueingpolicyDropTail,RED,CBQ,FQ,SFQ,DRR.12CreateaBasicNSSimulationCreatetheeventschedulerCreatenodesandlinksCreateconnectionsCreatetrafficsources/sinksEnabletracing.13Step3:CreateConnectionsTransports:TCP,UDP,multicast,etc.transportprotocolinstancesattachtonodes.14CreatingTransportChannels:UDPsourceandsinksetu_src[newAgent/UDP]setu_dst[newAgent/NULL]attachthemtonodes,thenconnecttoeachother$nsattach-agent$n0$u_src$nsattach-agent$n1$u_dst$nsconnect$u_src$u_dst.15CreatingTransportChannels:TCPsourceandsinksett_src[newAgent/TCP/Newreno]sett_dst[newAgent/TCPSink]attachtonodesandeachother$nsattach-agent$n0$t_src$nsattach-agent$n1$t_dst$nsconnect$t_src$t_dst.16CreateaBasicNSSimulationCreatetheeventschedulerCreatenodesandlinksCreateconnectionsCreatetrafficsources/sinksEnabletracing.17Step4:CreateTrafficModelsTraffic(applications):Web,ftp,telnet,audio,etc.applicationobjectsattachtotransportprotocolobjectsgeneratestrafficintotransportprotocol.18CreatingTrafficoverTCPChannelsHowtocreateaFTPsessionoverTCP?createtrafficmodelsetftp[newApplication/FTP]defaultis“infinite”filesizeattachtoTCPchannel$ftpattach-agent$t_srcschedulestarttime$nsat<time>“$ftpstart”.19CreatingTrafficoverUDPChannelsHowtocreateaCBR(ConstantBitRate)modeloverUDP?setcbr[newApplication/Traffic/CBR]$cbrsetpacketSize_512$cbrsetinterval_0.250$cbrattach-agent$u_src$nsat<time>“$cbrstart”.20CreateaBasicNSSimulationCreatetheeventschedulerCreatenodesandlinksCreateconnectionsCreatetrafficsources/sinksEnabletracing.21Step5：dumpeverythingintoatracefileOpenatracefile(defaultout.tr)andrecordtheinfoyouwanttotrace

setnd[openout.trw]$nstrace-all$nd.22TracepacketsonindividuallinksTracefileformat:<event><time><from><to><pkt><size>--<flowid><src><dst><seqno><aseqno>+102tcp900-------10.03.1715-102tcp900-------10.03.1715r1.0023402tcp900-------10.03.1715+enqueue

dequeuerreceiveddroptimenodesinvolvedinthiseventpackettypepacketlengthpacketflagsflowIDsourcedestaddressesseqnumberpacketIDTracing:dumpeverythingintoafile.23IntroductiontoNS-2:NS2网络仿真软件概述创建基本的NS2仿真场景一个完整的例子模型说明运行和结果分析高级主题如何添加新协议.24一个完整的例子acksfullduplexacksfullduplexNode2Node0Node1.25一个完整的例子2FTPsourcesOneOn-OffSource(voice)acks12TCPdestOneOn-OffdestOneCBRdest2Mbpsfullduplex5msecpropdelay100packetbufferDrop-tailpolicyacks1Mbpsfullduplex10msecpropdelay700packetbufferDrop-tailpolicy10FTPsourcesOneUDP2TCPSACKW_max=32MSS=140010TCPNewRenoW_max=32MSS=1400Node0Node1Node2OneUDPOneCBRsource12FTPdestTwoUDPdestfatlinkthinlinkperformancetracing.26NSTracefile(linkn1->n2):

NS-trace.txt...+11.53344112tcp1440-------121.22.4962092r11.53569412tcp1440-------121.22.4651527-11.53721412exp180-------1000.22.132841528-11.53865412cbr1440-------1011.112.141551530r11.54721412tcp1440-------121.22.4661529+11.5472812tcp1440-------121.22.4972095r11.54865412exp180-------1000.22.132841528+11.5512cbr1440-------1011.112.142112096-11.55017412tcp1440-------121.22.4671534r11.56017412cbr1440-------1011.112.141551530-11.56169412exp180-------1000.22.132851532+11.5622212tcp1440-------121.22.4982097-11.56313412tcp1440-------121.22.4681537r11.57169412tcp1440-------121.22.4671534r11.57313412exp180-------1000.22.132851532-11.57465412exp180-------1000.22.132861536...0.0114sec=180*8/(10^6)+0.01.27FlowMonitor(linkn1->n2)Trace:

packet-trace.txt...103561394.693963512362412629060473010.53671575.387577739350313259580815701100113661759.834006166616113841018081570110011.53701944.0583990191849144810780815701100123802131.71086371380415121132081570110012.53822325.178644727122155811760815701100133822516.761545447012416131231081570110013.53952710.8647514290892167612810815702310144212912.34621869907511747132601631150231014.54323130.385842319376918051373016311502310154363344.5896974377333186214260

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15.54623571.381118231159719371475016311502310164773804.6531596587571995151801631150231016.54954049.592932656351920571562016311502310175314303.921177137932321361605016311502310....28.trfileprocessingGawkGnuplot，Xgraph.29Results-FlowStatisticsCongestionWindowsofFlow1andFlow2CumulativedroppedpacketsofFlow1andFlow2Red-TCPflow1Green-TCPflow2.30PerformanceQueueStatistics多次运行取平均值.31IntroductiontoNS-2:NS2网络仿真软件概述创建基本的NS2仿真场景一个完整的例子模型说明运行和结果分析高级主题如何添加新协议.32高级主题Otlc和C+