云南大學-軟件學院-計算機網(wǎng)絡(luò)原理-期末試題總結(jié)

PAGEPAGE7注意：這是04-05學期王老師出的試題。1．Ethernet使用的MAC協(xié)議是（1）。當發(fā)生沖突時，將進入二進制指數(shù)退避階段，對于第3次沖突，等待重傳的最長時間是512位時間的（2）倍。（1）A．ALOHA B．CSMA/CD C．CSMA/CA D．CSMA/DD（2）A．1 B．3 C．5 D．72．網(wǎng)絡(luò)體系結(jié)構(gòu)定義計算機網(wǎng)絡(luò)的分層結(jié)構(gòu)，TCP/IP模型和ISO/OSI參考模型是兩個主要的網(wǎng)絡(luò)模型，其中TCP/IP協(xié)議傳送層之上的層是（3）層，而ISO/OSI則是一個（4）層的模型。（3）A．應(yīng)用 B．表述 C．會話 D．網(wǎng)絡(luò)（4）A．4 B．5 C．6 D．73．傳統(tǒng)的以太網(wǎng)傳輸介質(zhì)是同軸電纜，其中使用粗同軸電纜的網(wǎng)絡(luò)稱為（5）網(wǎng)絡(luò)，使用細同軸電纜的網(wǎng)絡(luò)稱為（6）網(wǎng)絡(luò)。10Base-T網(wǎng)絡(luò)使用的傳輸介質(zhì)是無屏蔽雙絞線，簡稱為（7）。（5）A．5BASE B．10BASE-10 C．10BASE-5 D．10BASE-2（6）A．5BASE B．10BASE-10 C．10BASE-5 D．10BASE-2（7）A．UPT B．UTP C．UPP D．UUP4．有N個節(jié)點共享一條總傳輸速率為R的通信信道，若采用TDMA協(xié)議，則每個節(jié)點的平均傳輸速率是（8），而瞬時傳輸速率則為（9）；如果采用FDMA協(xié)議，則每個節(jié)點的平均傳輸為（10），而瞬時傳輸速率則為（11）。（8）A．R B．R/N C．NR D．2R（9）A．R B．R/N C．NR D．2R（10）A．R B．R/N C．NR D．2R（11）A．R B．R/N C．NR D．2R5．可靠傳輸協(xié)議rdt3.0的發(fā)送和接收窗口都是1，對其進行改進后的GBN協(xié)議和SR協(xié)議都把發(fā)送窗口尺寸擴大為N（>1）。但GBN協(xié)議的接收窗口為（12），而SR協(xié)議的接收窗口為（13）。對SR協(xié)議，若使用k位的序號，則其發(fā)送窗口尺寸應(yīng)（14）。（12）A．1 B．N/4 C．N/2 D．N（13）A．1 B．N/4 C．N/2 D．N（14）A．不大于2k B．等于2k C．不大于2k-1 D．等于2k-16．PPP協(xié)議可以用在（15）鏈路上，并使用（16）協(xié)議完成鏈路狀態(tài)的管理，使用（17）協(xié)議完成網(wǎng)絡(luò)層地址配置和壓縮方式協(xié)商。（15）A．多點對多點 B．點對點 C．點對多點 D．任何（16）A．CNP B．PLC C．LCP D．NCP（17）A．CNP B．PLC C．LCP D．NCP7．RTP協(xié)議和RTCP協(xié)議是TCP/IP協(xié)議的（18）層的擴充子層，H.323是（19）層協(xié)議。（18）A．應(yīng)用層 B．傳送層 C．網(wǎng)絡(luò)層 D．鏈路層（19）A．應(yīng)用層 B．傳送層 C．網(wǎng)絡(luò)層 D．鏈路層8．在以太網(wǎng)中，增加幀的尺寸將使信道利用率（20）。（20）A．提高 B．降低 C．保持恒定 D．無法斷定二、MatchthefollowingtaskstooneoftheTCP/IPlayers:(10%)Routedetermination (網(wǎng)絡(luò)層)TransmissionofSegment (運輸層)ASCIIchangedtoEBCDIC (鏈路層)Framedefined（鏈路層)Transmissionofdataframe (鏈路層)Provideslog-inandlogoutprocedures（應(yīng)用程)Selectsadestinationnetwork (網(wǎng)絡(luò)層)Providesservicesforthenetworkapplications (應(yīng)用層)Reliableend-to-enddatatransmission（運輸層)ProvidesE-mailandfiletransferservices （應(yīng)用程)三、Answerthefollowingquestions(20%)：（1）PleaseshowanexampleforeveryIPV4addressclasses.(5%)A類地址范圍(55)B類地址范圍(55)C類地址范圍(55)D類地址范圍(55)E類地址范圍(55)（2）ConsiderIPaddress8.Whatarethebroadcastaddressandnetworkaddresswhendefaultnetworkmaskisused?(5%)broadcastaddress:55networkaddress:（3）WhataretheformatandexampleofIPv6address?(5%)Considerplaintext“thisisatest”,andtheCaesarcipherofk=4isused.WhatistheCiphertextafterencrypting?(5%)四、Completefollowproblems.(35%)Supposewewanttotransmitthemessage10101001andprotectitfromerrorsusingtheCRCgeneratorx3+1.Uselongdivisiontodeterminethemessagethatshouldbetransmitted.（10%）2.ConsideraCSMA/CDnetworkrunningat100Mbps,overa1000mcablewithnorepeaters.Thesignalspeedinthecableis2×108m/sec.Whatistheminimumframesizeforcheckcollisionreliably?（10%3.SupposetwoEthernetnodesof10Mbps,AandB,areattachedtooppositeendsofa900mcable,andthereare4repeatersbetweenAandB.Ifthesizeofframeis1000bits,andthesignalpropagationspeedis2×108m/s,andeachrepeaterinserts20-bitdelay.(15%)(1)Whatistheone-waypropagationdelay(includingrepeaterdelays)betweenAandBinsecond?(2)HowlongtimeisnodeA’saframecompletelydeliveredatnodeB?五、ConsideraLANshownbelowandoneclassCaddress/24isavailableonly.Pleaseaccomplishthefollowingquestions:(15%)AssignIPNetworknumberandnetmaskforallLANs.R11R113ABHUBEFHUBCDHUB2R212allnetworkinterfaces.DeterminetheroutetableonrouterR1.Answer:（1）網(wǎng)絡(luò)地址分配網(wǎng)絡(luò)網(wǎng)絡(luò)地址網(wǎng)絡(luò)掩碼A、B、R1-1/26C、D、R1-24/26R1-3、R2-128/26E、F、R2-292/26（2）端口IP地址分配端口IP地址端口IP地址端口IP地址AC5E93BD6F94R1-13R1-226R2-254R1-390R2-189（3）R1上的路由表Dest.NetworknextrouterNhopsInterface三、Answerfollowquestions.(20%)（1）HowbigistheEthernetaddressspace?TheIPv4addressspace?(5%)（2）Compareandcontrastlink-stateanddistance-vectorroutingalgorithm.(5%)（3）Foracommunicationsessionbetweentwohosts,whichhostistheclientandwhichistheserver?(5%)（4）Considerciphertext“wklvlvdwhvw”,andtheCaesarcipherofk=3isused.Whatistheplaintextaccordingly?(5%)五、Completefollowproblems.(35%)1.Supposewewanttotransmitthemessage10110001.FindtheCRCfieldofpacketthatshouldbetransmittedwhengeneratorx3+x+1isused.(10%)2.Supposetheround-trippropagationdelayforETHERNETis51.2μs.Thisyieldsaminimumpacketsizeof64bytes.Whatistheminimumpacketsizeifthedelaytimeheldconstant(i.e.51.2μs)whenthetransmissionraterisesto100Mbps?Why?(10%)SupposetwoEthernetnodesof10Mbps,AandB,areattachedtooppositeendsofa900mcable,andthereare4repeatersbetweenAandB.Ifthesizeofframeis1000bits,andthesignalpropagationspeedis2×108m/s,andeachrepeaterinserts20-bitdelay.HowlongtimeisnodeA’saframecompletelydeliveredatnodeB?(15%)//howbigistheethernetaddressspaceandtheIPv4addressspace?//consideclassCIPaddress202.203.208.*,supposeitbesubnetingintotwosubnets.Pleaseshowbeginaddress,endaddressandsubnetmaskofeverysubnet.24~255~12324、、pleaseenumeratethecharactersoflink-stateroutingalgorithmbriefly.paeaseenumeratethecharacteristicsofCSMA/CDprotocolbriefly計算：//1supposewewaretotransmitthemessage11011110.findtheCRCchechsumfieldofframethatshouldbetransmittedwhengeneratora=1101isused.010//2.considersendinga3000IPdatagramintoalinkthathasanMTVof600bytes.Howmanyftagmentsaregenerated?Whatateeneryfragment’sfragment-offset?討論//路由器的3種交換結(jié)構(gòu)(switchingfabrics)進行討論，指出他們的結(jié)構(gòu)，特點，適用性//討論Internet電子郵件應(yīng)用及相關(guān)協(xié)議，各相關(guān)協(xié)議的工作原理，在電子郵件中傳輸7位ASCII內(nèi)容的原理。討論TCP/IP協(xié)議集中的地址，各層地址的作用及尋址范圍//Dijkstras最短傳輸路徑大題//Considerarouterthatinterconnectsthreesubnets:subnet1,subnet2andsubnet3.supposethereisoneclassCIPaddress223.1.17.Xonly,subnet1isrequiredtosupportupto125interfaces,andsubnet2andsubnet3areeachrequiredtosuppsrtupto60interfaces.drawthenetworktopologgdiagram.Providethreenetworkaddresses(oftheforma,b,c,d/X)thatsatisfytheseconstraints.AssignIPaddresstoallnetworkinterfaceoftherouter.AssignIPaddresstotwonetworkinterfacesofeverysubnet期中重點第一章OSImodelTCP層次及各層次上的協(xié)議和設(shè)備數(shù)據(jù)封裝與解封裝的步驟（PDU）各種全稱（IPHTTPTCPUDP）domainname的組成網(wǎng)絡(luò)協(xié)議的定義組成部分（語法語義時序）delayinpacket-switched和nopers及tentconnection及相關(guān)計算（持續(xù)連接和非持續(xù)連接）（據(jù)說時延的計算一定會考）

第二章IPV4地址分類范圍IPV6地址簡介郵件的協(xié)議（SMTPPOP3。。。）SMTP會話的情景操作過程及名狀態(tài)行和命令行的作用NIME協(xié)議的作用

第三章網(wǎng)絡(luò)應(yīng)用進程尋址過程記住各種常見端口號（2021255380）TCP與UDP的特點可靠數(shù)據(jù)傳輸協(xié)議發(fā)送接收方的基本任務(wù)TCP連接建立