《数据通信与计算机网络》课件-03

313-1XI’ANJIAOTONGUNIVERSITY2009-12-142XI’ANJIAOTONGUNIVERSITY¾¾¾ARQ¾HDLCPPP¾¾¾¾ARQ¾ARQ¾HDLCPPP2009-12-143XI’ANJIAOTONGUNIVERSITY3.13.23.3ARQ3.4ARQ3.5HDLC3.6PPP2009-12-144XI’ANJIAOTONGUNIVERSITY3.1linkdatalink2009-12-145XI’ANJIAOTONGUNIVERSITY3.1procedure12345672009-12-146XI’ANJIAOTONGUNIVERSITY3.2ABAP2AP2AP1AP1323-22009-12-147XI’ANJIAOTONGUNIVERSITY3.22009-12-148XI’ANJIAOTONGUNIVERSITY3.2[1]dumb12345[1]11234[1]512009-12-149XI’ANJIAOTONGUNIVERSITY3.2ABDATADATADATADATABBBBABDATABDATAB2009-12-1410XI’ANJIAOTONGUNIVERSITY3.21ACKACKnowledgementACK2NAKNegativeACKACKACKNAK2009-12-1411XI’ANJIAOTONGUNIVERSITY3.23timeouttimer“”No334ACK2009-12-1412XI’ANJIAOTONGUNIVERSITY3.2ABDATA0ACKDATA1ACK(a)ABDATA0DATA0ACK(c)toutABDATA0ACKDATA0ACK(d)toutABDATA0NAKDATA0ACK(b)333-32009-12-1413XI’ANJIAOTONGUNIVERSITY3.2CRCFCSFrameCheckSequenceCRCaccept12009-12-1414XI’ANJIAOTONGUNIVERSITY3.2(1)V(S)←0{}(2)(3)N(S)←V(S){}(4)(5){}(6){(7)~(9)}(7)ACKV(S)←[1-V(S)]{}(3)(8)NAK(4)(9)(4)2009-12-1415XI’ANJIAOTONGUNIVERSITY3.2(1)V(R)←0{}(2)(3)(8)(4)N(S)=V(R){}(7)(5)(6)V(R)←[1-V(R)]{}(7)ACK(2)(8)NAK(2)2009-12-1416XI’ANJIAOTONGUNIVERSITY3.21V(S)N(S)V(S)2N(S)V(R)34NAK5ACKARQAutomaticRepeatreQuest2009-12-1417XI’ANJIAOTONGUNIVERSITY3.2ABDATADATAACKtptprtatptprtTtftout2009-12-1418XI’ANJIAOTONGUNIVERSITY3.23-23-33-4prpaprpouttttttt++++=2outptt=pfoutfTttttt2+=+=pavtTtN343-42009-12-1419XI’ANJIAOTONGUNIVERSITY3.23-53-63-7()()11111iiNippp∞−==−=−∑()1avTTtNttp==−maxλ()max11avTtptλ==−λ()1Tptλ≤−2009-12-1420XI’ANJIAOTONGUNIVERSITY3.23-83-9ARQARQ3-5()11ftpρλα≡≤−αTt1Tfttα≡≥()()111iavTTTitttipptp∞==+−=−∑2009-12-1421XI’ANJIAOTONGUNIVERSITY3.3ARQARQARQARQ2009-12-1422XI’ANJIAOTONGUNIVERSITY3.3ARQDATA0DATA1DATA2DATA3DATA4DATA5DATA2DATA3ACK1ACK2ACK1DATA0ACK2DATA1DATA2DATA3ACK2DATA4ACK2DATA5ACK2ACK3ACK3DATA2ACK4DATA3ACK4DATA5DATA4ABtout…??ACK2ACK2ACK22009-12-1423XI’ANJIAOTONGUNIVERSITY3.3ARQ12ACKnn-1n3ARQ22235Go-back-NARQNARQN2009-12-1424XI’ANJIAOTONGUNIVERSITY3.3ARQ(3-5)ARQ3-113-9ARQ3-123-13Ttft()()()11111iavfTfitttipptppα∞==+−=+−−⎡⎤⎣⎦∑αTtfouttt+{}max1/(1)/[1(1)]avftptpλα==−+−])1(1/[)1(pptf−+−≤=αλρ353-52009-12-1425XI’ANJIAOTONGUNIVERSITY3.3ARQARQ3-83-13ARQARQ()11ftpρλα≡≤−])1(1/[)1(pptf−+−≤=αλρ1α→()1p−α4α=0.01p=0.994ρ≤0.96ρ≤2009-12-1426XI’ANJIAOTONGUNIVERSITY3.3ARQARQTW2009-12-1427XI’ANJIAOTONGUNIVERSITY3.3ARQ1213412RW2009-12-1428XI’ANJIAOTONGUNIVERSITY3.3ARQARQ388No888122009-12-1429XI’ANJIAOTONGUNIVERSITY3.3ARQARQn21nTW≤−13247650ToutfWtt⎢⎥≤⎣⎦2009-12-1430XI’ANJIAOTONGUNIVERSITY3.3ARQ100bpfldlhl()111flbfbpplp=−−≈363-62009-12-1431XI’ANJIAOTONGUNIVERSITY3.3ARQ3-16ARQmaxλ()(){}max111ddfDlpltpλα==−+−⎡⎤⎣⎦C()ffdhtlCllC==+()1111ddhDlpUCllpα⎡⎤⎛⎞−==≤⎢⎥⎜⎟++−⎝⎠⎣⎦2009-12-1432XI’ANJIAOTONGUNIVERSITY3.4ARQARQARQ3-18RTWW≤2nRTWW+≤1222nnRW−≤=2009-12-1433XI’ANJIAOTONGUNIVERSITY3.5IBMBSCBinarySynchronousCommunicationASCIIBSC12341974IBMSNASDLCSynchronousDataLinkControlISOSDLCHDLCHigh-levelDataLinkControl2009-12-1434XI’ANJIAOTONGUNIVERSITY3.5primarystationcommandsecondarystationresponsecombinedstation2009-12-1435XI’ANJIAOTONGUNIVERSITY3.5NormalResponseMode,NRMpollingAsynchronousResponseMode,ARMAsynchronousBalancedModeABM888168InfoFFACFCSFCS2009-12-1436XI’ANJIAOTONGUNIVERSITY3.5FFlagF01001111110001010F51000100111110100010105100010011111010001010373-72009-12-1437XI’ANJIAOTONGUNIVERSITY3.510HDLCIInformationSSupervisoryUUn-nummbered2009-12-1438XI’ANJIAOTONGUNIVERSITY3.5N(S)N(R)N(R)N(R)piggybackingP/FARQRRReceiveReadyN(R)-1ACKRNRReceiveNotReadyN(R)-1REJRejectN(R)N(R)-1SREJSelectiveRejectN(R)N(R)-12009-12-1439XI’ANJIAOTONGUNIVERSITY3.515SNRMSABMSARMDISCUASNRMESABMEFRMRPoll/Final/01P1F1F1SIP1F12009-12-1440XI’ANJIAOTONGUNIVERSITY3.5+N(S)+N(R)P/F2009-12-1441XI’ANJIAOTONGUNIVERSITY3.6PPP(ISP)TCP/IPPPPTCP/IP…PC2009-12-1442XI’ANJIAOTONGUNIVERSITY3.6PPPSLIPSerialLineInternetProtocolSLIPIP1992PPPPPPRFC16611IP82LinkControlProtocol,LCP3NetworkControlProtocol,NCPIPDECnetAppleTalk383-82009-12-1443XI’ANJIAOTONGUNIVERSITY3.6PPPPPPHDLC0x7E01111110B0xFF0x030x0021IP0xC0210x8021IP1211121500PPP7EFF03FACFCSF7E2009-12-1444XI’ANJIAOTONGUNIVERSITY3.6PPPPPPPPP10x7EÆ0x7D,0x5E20x7DÆ0x7D,0x5D;3ASCII0x7DPPP1PPP2IP3FCS2009-12-1445XI’ANJIAOTONGUNIVERSITY3.6PPPPPP1ISPmodem2PCLCPPPP3NCPPCIPPC4NCPIPLCPmodem2009-12-1446XI’ANJIAOTONGUNIVERSITY3.6PPPNCP