網(wǎng)絡(luò)通信基礎(chǔ)

網(wǎng)絡(luò)通信基礎(chǔ)

workshop智能軟件研究所LiXC@ext:65262/6/20231AmoiCorporation前言滄海一粟網(wǎng)絡(luò)需要“網(wǎng)絡(luò)人才”Allinterconnecting…任何問(wèn)題大家都可以參與討論2/6/20232AmoiCorporation內(nèi)容綜述通信技術(shù)網(wǎng)絡(luò)結(jié)構(gòu)TCP/IP協(xié)議總結(jié)2/6/20233AmoiCorporation網(wǎng)絡(luò)通訊發(fā)展趨勢(shì)一個(gè)目標(biāo)：建成完善的信息基礎(chǔ)設(shè)施，使得任何人在任何地點(diǎn)、任何時(shí)間都可以接入聲音、多媒體、信息等服務(wù)。兩個(gè)支撐：微電子和光技術(shù)三個(gè)融合：計(jì)算機(jī)、通信、信息內(nèi)容的融合四個(gè)熱點(diǎn)：多媒體、寬帶網(wǎng)、移動(dòng)通信、信息安全2/6/20234AmoiCorporation現(xiàn)有的媒體服務(wù)http://www.ebu.ch/trev_293-ribas.pdf2/6/20235AmoiCorporation移動(dòng)通信的發(fā)展趨勢(shì) 系統(tǒng)、業(yè)務(wù)和覆蓋的無(wú)縫性移動(dòng)性、高用戶(hù)容量、寬帶化、IP化2/6/20236AmoiCorporation內(nèi)容綜述通信技術(shù)傳輸技術(shù)交換技術(shù)網(wǎng)絡(luò)結(jié)構(gòu)TCP/IP協(xié)議總結(jié)2/6/20237AmoiCorporation傳輸技術(shù)種類(lèi)：模擬，數(shù)字三個(gè)組成部分?jǐn)?shù)據(jù)信號(hào)傳輸方式2/6/20238AmoiCorporation模擬數(shù)據(jù)傳輸http://sunsite.queensu.ca/rmc/BUSADM/desc384/Slides/Week2-B.PPT2/6/20239AmoiCorporation對(duì)模擬信號(hào)的數(shù)字編碼脈沖編碼調(diào)制（pulse-codemodulation，PCM）基于采樣定理當(dāng)然還有其他的編碼：非線(xiàn)性編碼2/6/202310AmoiCorporation數(shù)字?jǐn)?shù)據(jù)傳輸http://sunsite.queensu.ca/rmc/BUSADM/desc384/Slides/Week2-B.PPT2/6/202311AmoiCorporation對(duì)數(shù)字信號(hào)的數(shù)字編碼最簡(jiǎn)單的方式用不同的電平來(lái)表示二進(jìn)制：負(fù)電平=1，正電平=0（NRZ-Lnonreturn-to-zerolevel）問(wèn)題：難以決定一位的結(jié)束和開(kāi)始無(wú)法定時(shí)或同步有累積的直流分量（電腐蝕等）2/6/202312AmoiCorporation數(shù)字編碼方式UsedinToken-ringUsedinEthernet自同步碼http://sunsite.queensu.ca/rmc/BUSADM/desc384/Slides/Week2-B.PPT2/6/202313AmoiCorporation問(wèn)題Ethernet?GSM?ADSL?2/6/202314AmoiCorporationServerInternetCORENetworkADSLExistingCopperADSL64Kbps-1.5to8Mbps16to768kbpsADSLConnection/pub/people/laf/Talks-2000-nonames/ADSL.PPTAsymmetricDigitalSubscriberLine

(ADSL)2/6/202315AmoiCorporationADSL簡(jiǎn)介Fullratestandard:

G.dmt=ITUG.992.1=ANSIT1.413,Iss.2Downstream(DS):64kbps-8.192MbpsUpstream(US):16kbps-768kbps"Splitterless",lowpowerstandard:

G.lite=ITUG.992.2DS:64kbps-1.5MbpsUS:16kbps-368kbps2/6/202316AmoiCorporationADSL接入框圖/lyii/lyii/kuanp/11-1-03.htm2/6/202317AmoiCorporationFDMPOTSPOTSUpstreamUpstreamDownstreamDownstreamEchoCancellationFrequencyFrequency1Mhz1MhzCreateMultipleChannel/pub/people/laf/Talks-2000-nonames/ADSL.PPTADSL頻譜示意圖2/6/202318AmoiCorporationADSL信道分配圖/products/adsl/techappqa.html2/6/202319AmoiCorporation信道帶寬BandwidthsPOTS:300Hzto3.4kHzISDN70kHz(2B1Q)140kHz(4B3T)G.dmtUS:25kHzto138kHz(7to31DMTtones)DS:138kHzto1.1MHz(FDM,32-255DMTtones)

25kHzto1.1MHz(EchoCancellation,7-255DMTtones)G.liteUS:25kHzto138kHzDS:138kHzto550kHz

2/6/202320AmoiCorporationADSL調(diào)制技術(shù)目前被廣泛采用的ADSL調(diào)制技術(shù)有3種：QAM(quadatureampli-tudemodulation)CAP(carrierlessamplitude-phasemodulation)DMT(discretemultitone)其中ＤＭＴ調(diào)制技術(shù)被ＡＮＳＩ標(biāo)準(zhǔn)化小組T1E1.4制訂的國(guó)家標(biāo)準(zhǔn)所采用。2/6/202321AmoiCorporationSplitterADSLmodemPhonePhoneTelephonelineVoice+ADSLVoice(only)ADSL(only)ADSL連接（1）/pub/people/laf/Talks-2000-nonames/ADSL.PPT2/6/202322AmoiCorporationADSL連接（2）http://rs1.szif.hu/~heckenas/okt/ADSL.pdf2/6/202323AmoiCorporation交換技術(shù)電路交換（circuitswitch）Telephoneswitch,2Gmobileswitch分組交換（packetswitch）Ethernetswitch,ATMswitch面向連接（虛電路，virtualcircuit）無(wú)連接（數(shù)據(jù)報(bào)，datagram）2/6/202324AmoiCorporation電路交換2/6/202325AmoiCorporation電路交換優(yōu)缺點(diǎn)優(yōu)點(diǎn)固定帶寬(保證容量)延遲變換小(基本不變)一般用于圖像和聲音的傳輸缺點(diǎn)線(xiàn)路利用率低，浪費(fèi)資源擴(kuò)展性差2/6/202326AmoiCorporation包交換2/6/202327AmoiCorporation包交換優(yōu)缺點(diǎn)優(yōu)點(diǎn)利用率高無(wú)需事先建立鏈路靈活缺點(diǎn)延時(shí)和帶寬無(wú)法保證(qualityofservice，QoS)2/6/202328AmoiCorporation內(nèi)容綜述通信技術(shù)網(wǎng)絡(luò)結(jié)構(gòu)局域網(wǎng)（LAN）廣域網(wǎng)（WAN）因特網(wǎng)（Internet）通信協(xié)議TCP/IP協(xié)議總結(jié)2/6/202329AmoiCorporation網(wǎng)絡(luò)概述網(wǎng)絡(luò)的作用：通過(guò)網(wǎng)絡(luò)來(lái)連接計(jì)算機(jī)，提供不同的服務(wù)網(wǎng)絡(luò)中的計(jì)算機(jī)起著不同的作用，來(lái)完成一個(gè)任務(wù)他們之間的關(guān)系可以是對(duì)等的，也可以是服務(wù)/客戶(hù)的模式常見(jiàn)的網(wǎng)絡(luò)結(jié)構(gòu)：局域網(wǎng)和廣域網(wǎng)局域網(wǎng)的互聯(lián)構(gòu)成廣域網(wǎng)2/6/202330AmoiCorporation局域網(wǎng)(LANs)

局域網(wǎng)的覆蓋范圍相對(duì)有限，如家庭，辦公室或者校園速度較快通常采用廣播的方式可以按照它的拓?fù)浣Y(jié)構(gòu)，使用的協(xié)議和傳輸介質(zhì)來(lái)分類(lèi)/~enda/ITFN1501/chapter07.ppt2/6/202331AmoiCorporation局域網(wǎng)絡(luò)的拓?fù)鋱D拓?fù)洌壕钟蚓W(wǎng)的組成分布，它定義了網(wǎng)絡(luò)的結(jié)構(gòu)物理拓?fù)洌何锢磉B接邏輯拓?fù)洌捍嫒鬏斀橘|(zhì)的方式2/6/202332AmoiCorporation總線(xiàn)結(jié)構(gòu)/~enda/ITFN1501/chapter07.ppt2/6/202333AmoiCorporation星形結(jié)構(gòu)/~enda/ITFN1501/chapter07.ppt2/6/202334AmoiCorporationStar-WiredRing

混合結(jié)構(gòu)

/~enda/ITFN1501/chapter07.ppt2/6/202335AmoiCorporation邏輯拓?fù)?~enda/ITFN1501/chapter07.ppt2/6/202336AmoiCorporation局域網(wǎng)(LANs)

局域網(wǎng)的覆蓋范圍相對(duì)有限，如家庭，辦公室或者校園速度較快通常采用廣播的方式可以按照它的拓?fù)浣Y(jié)構(gòu)，使用的協(xié)議和傳輸介質(zhì)來(lái)分類(lèi)/~enda/ITFN1501/chapter07.ppt2/6/202337AmoiCorporation協(xié)議?定義：協(xié)議是兩個(gè)或多個(gè)系統(tǒng)為了完成特定的任務(wù)而定義并交換的一系列消息（等價(jià)于通用語(yǔ)言）協(xié)議規(guī)范定義了這一消息序列，以及消息的格式/schools/nkhs/staff/jim_viner/A+/IT%201%20presentations/ITE-I-PPTs/ITE-I-ch09.ppt2/6/202338AmoiCorporationInternetworkPacket

Exchange/SequencedPacketExchangeInternetworkPacketExchange/SequencedPacketExchange(IPX/SPX)是由Novell公司提出的用于NovellNetware網(wǎng)絡(luò)IPX/SPX分別和IP/TCP對(duì)應(yīng)NWLink協(xié)議是微軟版IPX/SPX協(xié)議，從而可以和Novell網(wǎng)絡(luò)兼容2/6/202339AmoiCorporationNetBEUINetBIOSExtendedUserInterface(NetBEUI)主要用于小型網(wǎng)絡(luò)NetBEUI是一個(gè)簡(jiǎn)單的協(xié)議，只需配置它的計(jì)算機(jī)名字NetBEUI不具有路由功能2/6/202340AmoiCorporationAppleTalkAppleTalkiscomprisedofaesetofprotocolsthatspanthesevenlayersoftheOSIreferencemodel.AppleTalk可以運(yùn)行在Ethernet,TokenRing和Apple公司的LocalTalk網(wǎng)絡(luò)上/schools/nkhs/staff/jim_viner/A+/IT%201%20presentations/ITE-I-PPTs/ITE-I-ch09.ppt2/6/202341AmoiCorporationNetBIOSNetBIOS(網(wǎng)絡(luò)基本輸入/輸出系統(tǒng))：最初由IBM開(kāi)發(fā)，MS利用NetBIOS作為構(gòu)建LAN的上層協(xié)議NetBIOS使得程序和網(wǎng)絡(luò)之間有了標(biāo)準(zhǔn)的接口，方便應(yīng)用程序的開(kāi)發(fā)。并且可以移植到其他的網(wǎng)絡(luò)中NetBIOS位于OSI模型的會(huì)話(huà)層，也位于TCP/IP之上NetBIOS有兩種通訊模式–會(huì)話(huà)模式，一對(duì)一進(jìn)行通訊，LAN中的機(jī)器之間建立會(huì)話(huà)，可以傳輸較多的信息，并且可以檢查傳輸錯(cuò)誤–數(shù)據(jù)報(bào)模式。可以進(jìn)行廣播或者一對(duì)多的通訊，傳輸數(shù)據(jù)大小受限制，沒(méi)有錯(cuò)誤檢查機(jī)制，也不必建立通訊會(huì)話(huà)?NetBIOSoverTCP/IP，支持三種服務(wù)–名字服務(wù)–會(huì)話(huà)服務(wù)–數(shù)據(jù)包服務(wù)2/6/202342AmoiCorporationNetBIOS和WINSWINS是名字服務(wù)它是實(shí)現(xiàn)NetBIOS名字解析的一種方式(P-node)NetBIOS實(shí)現(xiàn)名字解析方式：B-node,P-node,M-node,H-mode2/6/202343AmoiCorporationIEEE802/~enda/ITFN1501/chapter07.ppt2/6/202344AmoiCorporationIEEE802.3幀結(jié)構(gòu)幀結(jié)構(gòu)描述數(shù)據(jù)包的格式/~enda/ITFN1501/chapter07.ppt2/6/202345AmoiCorporationEthernet標(biāo)準(zhǔn)一覽/~enda/ITFN1501/chapter07.ppt2/6/202346AmoiCorporation以太網(wǎng):10Base210:10Mbps;2:under200metersmaxcablelength采用細(xì)纜傳輸，總線(xiàn)拓?fù)浣Y(jié)構(gòu)repeatersusedtoconnectuptomultiplesegmentsrepeaterrepeatsbitsithearsononeinterfacetoitsotherinterfaces:physicallayerdeviceonly!http://www.swen.uwaterloo.ca/~kostas/ECE428/supporting-docs/chapter5-lan.ppt2/6/202347AmoiCorporation10BaseT和100BaseT10/100Mbps傳輸速率;后者稱(chēng)為“快速以太網(wǎng)”;T代表雙絞線(xiàn)（Twistedpair）它通常采用HubSwitch來(lái)連接不同的節(jié)點(diǎn)，因此是星形結(jié)構(gòu)（startopology）CSMA/CDimplementedathubMaxdistancefromnodetoHubis100meters2/6/202348AmoiCorporation局域網(wǎng)中要用到的設(shè)備2/6/202349AmoiCorporationEthernetHub物理層設(shè)備，和Repeater的功能類(lèi)似連接計(jì)算機(jī)和其他Ethernet網(wǎng)段無(wú)法阻止沖突/~cs458/slides/module16-lanswitchingV2.ppt2/6/202350AmoiCorporationEthernetHubsvs.EthernetSwitchesAnEthernetswitch是以太網(wǎng)的幀交換機(jī)Bufferingofframespreventscollisions.EachportisisolatedandbuildsitsowncollisiondomainAnEthernetHubdoesnotperformbuffering:Collisionsoccuriftwoframesarriveatthesametime.HubSwitch2/6/202351AmoiCorporation網(wǎng)橋（Bridges）網(wǎng)橋工作在DataLinkLayer(Layer2)層/~cs458/slides/module16-lanswitchingV2.ppt2/6/202352AmoiCorporation路由器（router）路由器工作在NetworkLayer(Layer3)層用于互聯(lián)IP網(wǎng)絡(luò)/~cs458/slides/module16-lanswitchingV2.ppt2/6/202353AmoiCorporation網(wǎng)關(guān)（Gateway）“Gateway”具有多重含義“Gateway”一般指路由器(Level3)，比如：defaultgateway“Gateway”也指用于連接具有不同第三層協(xié)議的多協(xié)議路由器，此時(shí)它還負(fù)責(zé)不同協(xié)議間的轉(zhuǎn)換(“Multi-protocolrouter”)。/~cs458/slides/module16-lanswitchingV2.ppt2/6/202354AmoiCorporation組網(wǎng)的趨勢(shì)1980s:LANs通過(guò)網(wǎng)橋互聯(lián)80年代末到90年代初:大量使用路由器90年代中期:LAN交換機(jī)取代了大多數(shù)的路由器2/6/202355AmoiCorporationInternet采用路由器組網(wǎng)RouterHubFDDIFDDI/~cs458/slides/module16-lanswitchingV2.ppt2/6/202356AmoiCorporationInternet采用交換機(jī)/網(wǎng)橋組網(wǎng)RouterSwitch/~cs458/slides/module16-lanswitchingV2.ppt2/6/202357AmoiCorporation原因？交換機(jī)vs.路由器Routers每個(gè)計(jì)算機(jī)的IPaddress必須配置如果網(wǎng)絡(luò)重構(gòu)，所有的IP地址都需要重新設(shè)定通過(guò)路由協(xié)議來(lái)建立路由表，如RIP或OSPF每個(gè)路由器都要處理數(shù)據(jù)包頭(如減少TTL域)Bridges/switchMAC地址是固化在硬件中無(wú)需網(wǎng)絡(luò)配置不需要路由協(xié)議learningbridgealgorithmspanningtreealgorithm無(wú)需對(duì)幀進(jìn)行操作2/6/202358AmoiCorporation無(wú)線(xiàn)局域網(wǎng)（WLAN）.au/documents/040120%20Wireless%20LAN.pdf2/6/202359AmoiCorporation802.11LANarchitecture無(wú)線(xiàn)主機(jī)和通過(guò)基站建立連接基站=接入點(diǎn)(AP)BasicServiceSet(BSS)(aka“cell”蜂窩)在基站模式下:無(wú)線(xiàn)主機(jī)接入點(diǎn)(AP)adhoc模式:只包含主機(jī)Multi-cell構(gòu)成了ExtendedServiceSet（ESS）BSS1BSS2Internethub,switchorrouterAPAPAllmaterialcopyright1996-2004，J.FKuroseandK.W.Ross,AllRightsReserved2/6/202360AmoiCorporationAd-hoc/~enda/ITFN1501/chapter07.ppt2/6/202361AmoiCorporation內(nèi)容綜述通信技術(shù)網(wǎng)絡(luò)結(jié)構(gòu)局域網(wǎng)（LAN）廣域網(wǎng)（WAN）移動(dòng)性（Mobility）因特網(wǎng)（Internet）TCP/IP協(xié)議總結(jié)2/6/202362AmoiCorporation廣域網(wǎng)(WANs)WAN是一個(gè)數(shù)據(jù)通信網(wǎng)絡(luò)，它的覆蓋范圍較大，因此通常采用一些廣域的通信方式一般涵蓋OSI的低三層，即:物理層，鏈路層，網(wǎng)絡(luò)層通過(guò)WAN接入方式互聯(lián)，可以是固定的或者是臨時(shí)的由于傳輸范圍較大，因此必須使用modem或CSU/DSU來(lái)建立連接2/6/202363AmoiCorporationWide-AreaNetwork(WAN)接入方式調(diào)制解調(diào)器ModemsIntegratedServicesDigitalNetwork(ISDN)Digitalsubscriberline(DSL):AsymmetricDSL(ADSL)HighDataRateDSL(HDSL)SymmetricDSL(SDSL)VeryHighDataRateDSL(VDSL)幀中繼FrameRelayAsynchronousTransferMode(ATM)TheT(US)andE(Europe)Carrierseries(T1,E1,T3,E3,andsoon)SynchronousOpticalNetwork(SONET)SDHGPRS，EGDE，3G數(shù)字微波2/6/202364AmoiCorporationWAN接入技術(shù)圖Allmaterialcopyright1996-2004，J.FKuroseandK.W.Ross,AllRightsReserved2/6/202365AmoiCorporationUMTS遠(yuǎn)景Seamlessend-to-endServiceInternetworkRoamingSatelliteGlobalSuburbanUrbanIn-BuildingPico-CellMicro-CellMacro-CellAudio/visualTerminalsHome-Cell

Source:ITUAllmaterialcopyright1996-2004，J.FKuroseandK.W.Ross,AllRightsReserved2/6/202366AmoiCorporation無(wú)線(xiàn)標(biāo)準(zhǔn)384Kbps56Kbps54Mbps5-11Mbps1Mbps802.15802.11b802.11{a,g}IS-95CDMA,GSMUMTS/WCDMA,CDMA2000

.11p-to-plink2G3GIndoor10–30mOutdoor50–200mMidrangeoutdoor200m–4KmLongrangeoutdoor5Km–20KmAllmaterialcopyright1996-2004，J.FKuroseandK.W.Ross,AllRightsReserved2/6/202367AmoiCorporationPAN(PersonalAreaNetwork)LAN(LocalAreaNetwork)WAN(WideAreaNetwork)MAN(MetropolitanAreaNetwork)PANLANMANWANStandardsBluetooth802.11HiperLAN2802.11MMDS,LMDSGSM,GPRS,CDMA,2.5-3GSpeed<1Mbps11to54Mbps11to100+Mbps10to384KbpsRangeShortMediumMedium-LongLongApplicationsPeer-to-PeerDevice-to-DeviceEnterprisenetworksT1replacement,lastmileaccessMobilePhones,cellulardataWirelessTechnologiesProvidedbyCisco,Inc.?Copyright20032/6/202368AmoiCorporation移動(dòng)性?從網(wǎng)絡(luò)角度看移動(dòng)性:沒(méi)有移動(dòng)性高移動(dòng)性用戶(hù)使用一個(gè)AP用戶(hù)在移動(dòng)中保持連接（經(jīng)過(guò)多個(gè)AP）用戶(hù)從網(wǎng)絡(luò)連接/斷開(kāi)，并通過(guò)DHCP獲得IP設(shè)置數(shù)據(jù)連接會(huì)中斷Allmaterialcopyright1996-2004，J.FKuroseandK.W.Ross,AllRightsReserved2/6/202369AmoiCorporation移動(dòng)性的構(gòu)成單元homenetwork:

移動(dòng)終端固定的家(e.g.,128.119.40/24)Permanentaddress:

固定的IP地址,永遠(yuǎn)有效e.g.,86homeagent:當(dāng)移動(dòng)終端不在home時(shí)，代替其執(zhí)行的單元wideareanetworkcorrespondentAllmaterialcopyright1996-2004，J.FKuroseandK.W.Ross,AllRightsReserved2/6/202370AmoiCorporation移動(dòng)性的構(gòu)成單元Care-of-address:

在訪問(wèn)網(wǎng)絡(luò)中的地址(e.g.,79,129.13.2)wideareanetworkvisitednetwork:

移動(dòng)終端目前所在網(wǎng)絡(luò)(e.g.,79.129.13/24)Permanentaddress:

保持不變(e.g.,86)foreignagent:訪問(wèn)網(wǎng)絡(luò)中累似homeagent的單元correspondent:希望和移動(dòng)終端通信的主機(jī)Allmaterialcopyright1996-2004，J.FKuroseandK.W.Ross,AllRightsReserved2/6/202371AmoiCorporation注冊(cè)結(jié)果：Foreignagent知道移動(dòng)終端存在Homeagent知道移動(dòng)終端目前的CoA通信采用UDPwideareanetworkhomenetworkvisitednetwork1ICMP路由通告移動(dòng)終端選擇CoA并注冊(cè)2foreignagent聯(lián)系homeagent通知移動(dòng)終端的位置，homeagent確認(rèn)注冊(cè)Allmaterialcopyright1996-2004，J.FKuroseandK.W.Ross,AllRightsReserved2/6/202372AmoiCorporationIndirectRouting傳輸wideareanetworkhomenetworkvisitednetwork3241correspondent采用移動(dòng)終端Permanentaddress作為目的地址homeagent把整個(gè)IP包封裝進(jìn)另一個(gè)IP包發(fā)給foreignagentforeignagent取出原來(lái)的IP包，轉(zhuǎn)發(fā)給移動(dòng)終端移動(dòng)終端采用correspondent地址直接回復(fù)，源地址仍為PAAllmaterialcopyright1996-2004，J.FKuroseandK.W.Ross,AllRightsReserved2/6/202373AmoiCorporationDirectRouting傳輸wideareanetworkhomenetworkvisitednetwork4251correspondent請(qǐng)求并得到FA地址correspondent轉(zhuǎn)發(fā)至foreignagentforeignagent轉(zhuǎn)發(fā)給移動(dòng)終端移動(dòng)終端直接回復(fù)correspondent3Allmaterialcopyright1996-2004，J.FKuroseandK.W.Ross,AllRightsReserved2/6/202374AmoiCorporationMobileIPv4:indirectrouting（RFC3220）Permanentaddress:86Care-ofaddress:dest:86packetsentbycorrespondentdest:dest:86packetsentbyhomeagenttoforeignagent:apacketwithinapacketdest:86foreign-agent-to-mobilepacketAllmaterialcopyright1996-2004，J.FKuroseandK.W.Ross,AllRightsReserved2/6/202375AmoiCorporationCareofAddress（CoA，RFC3220）有兩種CoAforeignagentcare-ofaddressanIPaddressoftheforeignagentInthismode,theforeignagentistheendpointofthetunnelGood：don’tplaceunnecessarydemandsonthealreadylimitedIPv4addressspaceBad：amobilenodeandthecurrentforeignagentMUSTbeabletoexchangedatagramswithoutrelyingonstandardIProutingmechanismsco-locatedcare-ofaddressacare-ofaddressacquiredbythemobilenodeasalocalIPaddress，suchasthroughDHCPthemobilenodeservesastheendpointofthetunnelGood：functionwithoutaforeignagentBad：placeadditionalburdenontheIPv4addressspace2/6/202376AmoiCorporation內(nèi)容綜述通信技術(shù)網(wǎng)絡(luò)結(jié)構(gòu)局域網(wǎng)（LAN）廣域網(wǎng)（WAN）因特網(wǎng)（Internet）通信協(xié)議TCP/IP協(xié)議總結(jié)2/6/202377AmoiCorporation因特網(wǎng)（Internet）使用TCP/IP協(xié)議廣域網(wǎng)發(fā)展階段：20世紀(jì)70年代初期ARPANET20世紀(jì)80年代NSFNET1987年以后，引進(jìn)一些商業(yè)網(wǎng)絡(luò)（如UUNET等）1994，進(jìn)入大規(guī)模商業(yè)運(yùn)作2/6/202378AmoiCorporationInternet的發(fā)展歷史1958:ARPA(高級(jí)研究規(guī)劃署)formedwithintheUSDept.ofDefensetofostertechnologicaladvanceswithmilitaryapplications1961:LeonardKleinrock’sPh.Dthesisdiscussespacketswitchingtheory1960-1965:PaulBaranconductsresearchonsurvivable,packetswitchednetworks1966-1967:ARPANET,thefirstwide-areapacketswitchednetwork,isproposed1971:23hostsonARPANET1972:Firstemailprogramisabighit1973:InternationalARPANETconnectionstoEnglandandNorwayBobMetcalfeinventsEthernetFTPspecification2/6/202379AmoiCorporationInternet的發(fā)展歷史（cont）1974:AnearlyversionofTCP/IPspecifiedbyVintCerfandRobertKahn1981:TCP/IPdistributedwithBSDUNIX1983:TCP/IPstandardizedforallARPANEThosts“Internet”termused1984:1000hostsonARPANETDNSintroduced1986:NSFNETcreated（usingTCP/IP）tolink5USsupercomputercenters（T1=1.544Mb/s）IETFcreated（Firstmeetinghad15attendees）2/6/202380AmoiCorporationInternet的發(fā)展歷史（cont）1990:ARPANETturnedoffFirstcommercialconsumerorientedISPfounded（TheWorld;）1991:NSFNETupgradedtoT3WWWreleasedbyCERN1993:NCSAMosaicreleasedasfirstgraphicalWWWbrowser1994:Firstwaveofmassivecommercialization1995:NSFNETturnedoffCommercialbackboneproviders(e.g.,MCI,Sprint,UUNET,etc.)replaceit2/6/202381AmoiCorporation今天的Internet架構(gòu)(概念)/mike/MITP432/01%20introduction.pdf2/6/202382AmoiCorporationExampleBackbone:AT&T2/6/202383AmoiCorporation加入Internet/mike/MITP432/01%20introduction.pdf2/6/202384AmoiCorporationInternet的規(guī)模（保守估計(jì)）/mike/MITP432/01%20introduction.pdf2/6/202385AmoiCorporation我們需要標(biāo)準(zhǔn)和協(xié)議標(biāo)準(zhǔn)就是一致同意的規(guī)則，包括設(shè)計(jì)、處理和通信目的：確保不同廠家設(shè)備在數(shù)據(jù)處理、通信上的互操作性Internet要求使用TCP/IP協(xié)議族Internet的標(biāo)準(zhǔn)都是由InternetEngineeringTaskForce(IETF)制定的，并且是開(kāi)放的主要制定Layer3到Layer72/6/202386AmoiCorporationInternet管理結(jié)構(gòu)ICANNIANAISOC（Internet協(xié)會(huì)）IESG（工程指導(dǎo)小組）IRTFIETFIABFundingReview.au/DTF/talks/ArnoldProtocols.ppt#258,6,Structure域名和地址管理長(zhǎng)期研究項(xiàng)目技術(shù)顧問(wèn)工程部2/6/202387AmoiCorporation主要的標(biāo)準(zhǔn)制定組織IETF:–Internetprotocolsandapplications()–RequestForComments(RFCs)whichdescribehowtheInternetprotocolsworkITU(formerlyCCITT):–Manyaspectsoftelecommunications()IEEE:–Mostlyphysicalanddatalink;e.g.,802.xseries()3GPP,3GPP2,OMA:–WirelessRFandIPstandards,leveragingIETFworkManyothers…–Cablelabs,DSLForum,ATMForum,SoftswitchForum,etc.2/6/202388AmoiCorporationhttp://www.cs.ucy.ac.cy/courses/EPL653/papers/IETF%20standards%20process.ppt2/6/202389AmoiCorporation一些重要的RFCRFC768–UserDatagramProtocol(UDP)RFC791–InternetProtocol(IP)RFC792–InternetControlMessageProtocol(ICMP)RFC793–TransmissionControlProtocol(TCP)RFC826–AddressResolutionProtocol(ARP)RFC1035–DomainNames–ImplementationandSpecificationRFC1112–HostExtensionsforIPMulticasting(IGMP)RFC2131–DynamicHostConfigurationProtocol(DHCP)RFC2616–HypertextTransferProtocol(HTTP)…andmanymore/rfcs2/6/202390AmoiCorporation內(nèi)容綜述通信技術(shù)網(wǎng)絡(luò)結(jié)構(gòu)TCP/IP協(xié)議TCP/IP基礎(chǔ)HTTP示例DNS/DHCP應(yīng)用工具Socket編程IPv6總結(jié)2/6/202391AmoiCorporationTCP/IPSuiteandOSIReferenceModel/schools/nkhs/staff/jim_viner/A+/IT%201%20presentations/ITE-I-PPTs/ITE-I-ch09.ppt2/6/202392AmoiCorporationOSI各層簡(jiǎn)介物理層（PhysicalLayer）：主要功能為定義了網(wǎng)絡(luò)的物理結(jié)構(gòu)，傳輸?shù)碾姶艠?biāo)準(zhǔn)，Bit流的編碼及網(wǎng)絡(luò)的時(shí)間原則，如分時(shí)復(fù)用及分頻復(fù)用。決定了網(wǎng)絡(luò)連接類(lèi)型（端到端或多端連接）及物理拓?fù)浣Y(jié)構(gòu)。說(shuō)的通俗一些，這一層主要負(fù)責(zé)實(shí)際的信號(hào)傳輸。據(jù)鏈路層（DataLinkReview）：在兩個(gè)主機(jī)上建立數(shù)據(jù)鏈路連接，向物理層傳輸數(shù)據(jù)信號(hào)，并對(duì)信號(hào)進(jìn)行處理使之無(wú)差錯(cuò)并合理的傳輸。

網(wǎng)絡(luò)層（NetworkLayer）：主要負(fù)責(zé)路由，選擇合適的路徑，進(jìn)行阻塞控制等功能。

傳輸層（TransferLayer）：最關(guān)鍵的一層，向擁護(hù)提供可靠的端到端（End-to-End）服務(wù)，它屏蔽了下層的數(shù)據(jù)通信細(xì)節(jié)，讓用戶(hù)及應(yīng)用程序不需要考慮實(shí)際的通信方法。

會(huì)話(huà)層（SessionLayer）：主要負(fù)責(zé)兩個(gè)會(huì)話(huà)進(jìn)程之間的通信，即兩個(gè)會(huì)話(huà)層實(shí)體之間的信息交換，管理數(shù)據(jù)的交換。

表示層（PresentationLayer）：處理通信信號(hào)的表示方法，進(jìn)行不同的格式之間的翻譯，并負(fù)責(zé)數(shù)據(jù)的加密解密，數(shù)據(jù)的壓縮與恢復(fù)。

應(yīng)用層（ApplicationLayer）：保持應(yīng)用程序之間建立連接所需要的數(shù)據(jù)記錄，為用戶(hù)服務(wù)。2/6/202393AmoiCorporation分層的益處便于討論和學(xué)習(xí)協(xié)議規(guī)范的細(xì)節(jié)。標(biāo)準(zhǔn)化層之間的界面，使得不同的產(chǎn)品可以在相同的層相同的功能。建立更好的互操作性。降低了復(fù)雜性。易于排錯(cuò)。每一層都在用戶(hù)數(shù)據(jù)周?chē)由项^和尾，排錯(cuò)失可以察看這些信息。每一層都給其上一層提供服務(wù)。所以，可以清晰的區(qū)分每一層的功能。2/6/202394AmoiCorporationTCP/IP分層模型TCP/IP采用分層模型四層：應(yīng)用層傳輸層網(wǎng)絡(luò)層（IP層）網(wǎng)絡(luò)接口層每個(gè)主機(jī)會(huì)實(shí)現(xiàn)所有的四層功能，中間結(jié)點(diǎn)（如Gateways/Routers)只實(shí)現(xiàn)低兩層的功能/~cs458/slides/module02-reviewV2.ppt2/6/202395AmoiCorporation每層的功能DataLinkLayer:Service: 提供可靠的幀傳輸和媒體控制協(xié)議（沒(méi)有指定，因此它可 以基于LAN,MAN,WAN中的技術(shù)）Functions: 組幀,媒體接入控制,糾錯(cuò)NetworkLayer:Service: 將包從源端發(fā)到接收端Functions: 路由，地址TransportLayer:Service: 提供端到端的數(shù)據(jù)傳輸Functions: 建立連接/終止連接,流控和錯(cuò)誤控制ApplicationLayer:Service: 特定的應(yīng)用(收發(fā)email,存取HTML文件,交換文件Functions: 和特定的應(yīng)用相關(guān)2/6/202396AmoiCorporation協(xié)議族和分層模型相對(duì)應(yīng)/~cs458/slides/module02-reviewV2.ppt2/6/202397AmoiCorporationTCP/IP所使用的地址端口地址IP地址物理地址2/6/202398AmoiCorporation端口地址定義：給計(jì)算機(jī)上的進(jìn)程所指派的標(biāo)號(hào)（16位長(zhǎng)）Internet上的許多服務(wù)都有特定的端口號(hào)，稱(chēng)為well-knownports，例如：ftp 21 finger 79telnet 23 http 80smtp 25 nntp 119TheWellKnownPorts是由IANA來(lái)指定和管理的，它的范圍是0-1023.Well-knowports的RFC17002/6/202399AmoiCorporation90012085“OntheInternet…”

youarenothingbutanIPAddress!42/resources/data/WoN/itu-seminar-20040211-1.ppt2/6/2023100AmoiCorporationIPv4AddressesFixedlength:32bits（IPv6128bits）Initialclassfulstructure(1981)TotalIPaddresssize:4billion=232ClassA:128networks,16MhostsClassB:16Knetworks,64KhostsClassC:2Mnetworks,256hostsHighOrderBits010110Format7bitsofnet,24bitsofhost14bitsofnet,16bitsofhost21bitsofnet,8bitsofhostClassABC2/6/2023101AmoiCorporationIPAddressClasses

(SomeareObsolete)NetworkIDHostIDNetworkIDHostID816ClassA320ClassB10ClassC110MulticastAddressesClassD1110ReservedforexperimentsClassE111124/afs/cs/academic/class/15441-f01/www/lectures/lecture07.ppt2/6/2023102AmoiCorporation子網(wǎng)劃分RFC917(1984)ForclassB&CnetworksVeryfewLANshavecloseto64KhostsNeedsimplewaytogetmultiple“networks”Usebridging,multipleIPnetworksorsplitupsinglenetworkaddressranges(subnet)Mustreducethetotalnumberofnetworkaddressesthatareassigned2/6/2023103AmoiCorporationSubnettingVariablelengthsubnetmasksCouldsubnetaclassBintoseveralchunksSupernetting？NetworkHostNetworkHostSubnet1111..00000000..1111Mask/afs/cs/academic/class/15441-f01/www/lectures/lecture07.ppt2/6/2023104AmoiCorporationsubnetting/cs143/slides/2004-10-05-ip-addressing-and-dns.pdf2/6/2023105AmoiCorporationSupernettingAsupernetisablockofconsecutivenetworkaddresses/cs143/slides/2004-10-05-ip-addressing-and-dns.pdf2/6/2023106AmoiCorporation地址管理–1990’sEarly1990’s:InternetscalingproblemsAddressdepletionduetoclassfularchitecture(A,B,C)RoutingtableoverloadDuetolackofrouteaggregation2/6/2023107AmoiCorporation地址管理–1990’sInternetwidelyprojectedtofailGrowthwouldstopbymid-’90sUrgentmeasuresrequiredActiontakenbyIETF/Internetcommunity1993:Developmentof“CIDR”addressedbothtechnicalproblemsAddressdepletionThroughmoreaccurateassignmentRoutingtableoverloadThroughaddressspaceaggregationRFC1519RFC1518RFC15172/6/2023108AmoiCorporationNetworkboundariesmayoccuratanybitClassful&Classlessaddressing16Knetworksx64Khosts

128networksx16MhostsAB2Mnetworksx256hostsCObsolete

inefficientdepletionofBspacetoomanyroutesfromCspaceClassfulClasslessBestCurrentPracticeHostsPrefixClassful.........8/2916/2832/2764/26128/25256/241C.........4096/2016C8192/1932C163843276865536

/18/17

/1664C128C1B........./afs/cs/academic/class/15441-f01/www/lectures/lecture07.ppt2/6/2023109AmoiCorporationIPAddresses:Howtodistribute?Network(networkportion):GetallocatedportionofISP’saddressspace:ISP'sblock11001000000101110001000000000000/20Organization011001000000101110001000000000000/23Organization111001000000101110001001000000000/23Organization211001000000101110001010000000000/23...…..….….Organization711001000000101110001111000000000/23

2/6/2023110AmoiCorporation一些特殊的IP地址:localhost(a.k.a.theloopbackaddressHostbits全0:網(wǎng)絡(luò)地址Hostbits全1:廣播地址（直接廣播）32bit全為1的地址用于本網(wǎng)廣播（啟動(dòng)時(shí)使用）為專(zhuān)用網(wǎng)使用的地址10.0.0172.16–172.31192.168.0–192.168.2552/6/2023111AmoiCorporation問(wèn)題地址2/27的網(wǎng)絡(luò)地址？假設(shè)公司申請(qǐng)的地址是150.100，下面網(wǎng)絡(luò)的子網(wǎng)掩碼？H1H2H3H4R128547629ToInternet542/6/2023112AmoiCorporationMAC地址LAN上的每個(gè)網(wǎng)卡都有全球唯一的MAC地址Broadcastaddress=FF-FF-FF-FF-FF-FF=adapter1A-2F-BB-76-09-AD58-23-D7-FA-20-B00C-C4-11-6F-E3-9871-65-F7-2B-08-53

LAN(wiredorwireless)http://www.ia.hiof.no/datane/3rdEditionChapter5-del3.ppt2/6/2023113AmoiCorporationMAC地址MAC地址由IEEE管理每個(gè)網(wǎng)卡制造商占用一部分的MAC地址空間(從而確保唯一性)MACflataddress?可移植性好網(wǎng)卡可以加入任何一個(gè)同型的網(wǎng)絡(luò)2/6/2023114AmoiCorporationARP和RARP要點(diǎn):Internet是基于IP地址Datalink層的協(xié)議(Ethernet,FDDI,ATM)具有不同的MAC地址ARP和RARP協(xié)議用來(lái)轉(zhuǎn)換IP和MAC地址/~cs458/bookslides/module06-arpV2.ppt2/6/2023115AmoiCorporationARP/RARP協(xié)議（RFC826/903）/~cs458/bookslides/module06-arpV2.ppt2/6/2023116AmoiCorporationARP的地址查找過(guò)程ARPRequest:

它的請(qǐng)求是通過(guò)廣播發(fā)送，回答是單播發(fā)送2/6/2023117AmoiCorporationARP的地址查找過(guò)程ARPReply:

Router137respondswithanARPReplywhichcontainsthehardwareaddress2/6/2023118AmoiCorporationARP包的格式2/6/2023119AmoiCorporationARP/RARPPacketHardwaretype(1=Ethernet)Protocoltype(sameasEthertypefield:0x0806=ARP

request/reply,0x8035=RARPrequest/reply RFC960)HLEN:Hardwareaddresslength:(Ethernet=6)PLEN:Protocoladdresslength(IP=4)Operation:(1=ARPrequest,2=ARPreply,

3=RARPrequest,4=RARPreply)SenderHardwareAddress(RequestedEthernetaddressinARPreply)SenderIPaddressTargetHATargetIP(IPaddressneedingresolutioninARPrequest)2/6/2023120AmoiCorporationARPrequestB.AForouzan,TCP/IPProtocolSuite2/6/2023121AmoiCorporationARPreplyB.AForouzan,TCP/IPProtocolSuite2/6/2023122AmoiCorporationARP2/6/2023123AmoiCorporation例子00105cf6531f000d656c687f08004500MACaddress(Dest)MACaddress(source)Eth.Tp.(IP)0030865d40007f06cdbf0a64fb440a64979e1f90042d3d9c5018d9cd046770124470074e0000020405b4010104022/6/2023124AmoiCorporationIPHeader格式（RFC791）.tw/TANet/info/06.ppt2/6/2023125AmoiCorporationTOS格式Bits0-2:Precedence.0~7.資料傳送的優(yōu)先順序Bits3:0=NormalDelay,1=LowDelayBits4:0=NormalThroughput,1=HighThroughputBits5:0=NormalReliability1=HighReliabilityBits6-7:保留未來(lái)使用2/6/2023126AmoiCorporationAssignedProtocolNumber(RFC790)十進(jìn)制表示：1ICMP6TCP14Telenet17UserDatagram(UDP)2/6/2023127AmoiCorporationFlagsFlags:3bits(VariousControlFlags)Bit0:reserved,mustbezeroBit1:(DF)0=MayFragment,1=Don'tFragment.Bit2:(MF)0=LastFragment,1=MoreFragments.2/6/2023128AmoiCorporation例子00105cf6531f000d656c687f08004500MACaddress(Dest)MACaddress(source)Eth.Tp.(IP)V420tos0030865d40007f06cdbf0a64fb440a64Totl.48BytesId:34397DF=1FrmoffTTL=127TCPChk.sum.8SourceIPaddr.58979e1f90042d3d9c5018d9cd04677012Dest.Addr.4470074e0000020405b4010104022/6/2023129AmoiCorporationTCP:OverviewRFCs:793,1122,1323,2018,2581fullduplexdata:bi-directionaldataflowinsameconnectionMSS:maximumsegmentsize（option）connection-oriented:

handshaking(exchangeofcontrolmsgs)init’ssender,receiverstatebeforedataexchangeflowcontrolled:senderwillnotoverwhelmreceiverpoint-to-point:onesender,onereceiver

reliable,in-orderbytesteam:no“messageboundaries”pipelined:TCPcongestionandflowcontrolsetwindowsizesend&receivebuffershttp://www.cs.tau.ac.il/~natali/OS/OStcp.ppt2/6/2023130AmoiCorporationTCPsegmentstructuresourceport#destport#32bitsapplicationdata(variablelength)sequencenumberacknowledgementnumberrcvrwindowsizeptrurgentdatachecksumFSRPAUheadlennotusedOptions(variablelength)URG:urgentdata(generallynotused)ACK:ACK#validPSH:pushdatanow(generallynotused)RST,SYN,FIN:connectionestab(setup,teardowncommands)#bytesrcvrwillingtoacceptcountingbybytesofdata(notsegments!)Internetchecksum(asinUDP)http://www.cs.tau.ac.il/~natali/OS/OStcp.ppt2/6/2023131AmoiCorporationFlags域ControlBits6bits(fromlefttoright):URG:UrgentPointerfieldsignificantACK:AcknowledgmentfieldsignificantPSH:PushFunctionRST:ResettheconnectionSYN:SynchronizesequencenumbersFIN:Nomoredatafromsender2/6/2023132AmoiCorporation例子00105cf6531f000d656c687f08004500MACaddress(Dest)MACaddress(source)Eth.Tp.(IP)V420tos0030865d40007f06cdbf0a64fb440a64Totl.48BytesId:34397DF=1Frmoff=0TTL=127TCPChk.sum.8SourceIPaddr.58979e1f90042d3d9c5018d9cd04677012Dest.Addr.8080s.port1069d.port1033654296Seq.num3654091879Ack.numDataoffset=28BytesAcksyn4470074e0000020405b401010402Window=17520Chk.Sum.Urg.Ptr.Opt.maxseg=1460…..2/6/2023133AmoiCorporationTCPHandshakeSYNRQSTSYNACKclientserverACKSeq=2121323ACK=2121324,Seq=122222http://www.cs.tau.ac.il/~natali/OS/OStcp.ppt2/6/2023134AmoiCorporationTCPseq.#’sandACKsSeq.#’s:bytestream“number”offirstbyteinsegment’sdataACKs:seq#ofnextbyteexpectedfromothersidecumulativeACKHostAHostBSeq=42,ACK=79,data=‘C’Seq=79,ACK=43,data=‘C’S