計(jì)網(wǎng)試驗(yàn)data-link-layer-simulation

1、計(jì)算機(jī)通信與網(wǎng)絡(luò)實(shí)驗(yàn)課程實(shí)驗(yàn)報(bào)告實(shí)驗(yàn)二:2.datalinklayersimulation實(shí)驗(yàn)名稱(chēng)：2.datalinklayersimulation1.實(shí)驗(yàn)內(nèi)容I.DrawFigure7.12and7.13.2.SimulationonPerformanceofDataLinkControlProtocolsUsingthesameassumptionsthatareusedforFigure7.13inAppendix7A,plotlineutilizationasafunctionofP,theprobabilitythatasingleframeisinerrorforthefollo

2、wingerror-controltechniques:a. Stop-and-waitb. Go-back-Nwithw=7c. Go-back-Nwithw=127d. Selectiverejectwithw=7e. Selectiverejectwithw=127Doalloftheprecedingforthefollowingvaluesofa:0.1,1,10,100.Drawconclusionsaboutwhichtechniqueisappropriateforvariousrangesof.2 .實(shí)驗(yàn)結(jié)果A=0.1240后|一國(guó)自一A=100a=0.1時(shí)，W=7或者127

3、都是大于2a+1;a=1時(shí)，W=7或者127都是大于2a+1;a=10時(shí)，則選擇拒絕和返回N都是一個(gè)分段函數(shù).a=100時(shí)，則選擇拒絕和返回N都是一個(gè)分段函數(shù)。3 .實(shí)驗(yàn)程序Figure7.12a=0:0.1:1000;W=1,7,127;forj=1:3fori=1:length(a)ifW(j)>=2*a(i)+1U(i)=1;elseU(i)=W(j)/(2*a(i)+1);endendifj=1W1=U;endifj=2W7=U;endifj=3W10=U;endendplot(a,W1);holdon;plot(a,W7);plot(a,W10);set(gca,'xs

4、cale','log');axis(0.1100001);Figure7.13a=0:0.1:1000;W=1,7,127,127;P=10A(-3);forj=1:4fori=1:length(a)ifW(j)=1U(i)=(1-P)/(1+2*a(i);endifW(j)=7ifW(2)>=2*a(i)+1U(i)=1-P;elseU(i)=W(j)*(1-P)/(2*a(i)+1);endendifW(j)=127ifW(j)>=2*a(i)+1U(i)=(1-P)/(1+2*a(i)*P);Y(i)=1-P;elseU(i)=W(j)*(1-P)/(

5、2*a(i)+1)*(1-P+W(j)*P);Y(i)=W(j)*(1-P)/(2*a(i)+1);endendifj=1W1=U;endifj=2W7=U;endifj=3W10=U;endifj=4W=Y;endendendplot(a,W1);holdon;plot(a,W7);plot(a,W10);plot(a,W);set(gca,'xscale','log');axis(0.1100001);2、DrawfunctionU=stopandwait(a,P)U=(1-P)./(1+2*a);endfunctionU=selective_reject(

6、a,W,P)U=(1-P).*(W>=2*a+1)+W.*(1-P)./(2.*a+1).*(W<2*a+1);endfunctionU=gobackn(a,W,P)U=(1-P)./(1+2.*a.*P).*(W>=2*a+1)+W.*(1-P)./(2.*a+1)./(1-P+W.*P).*(W<2*a+1);endfunctionlab2_draw(a)P=0:0.1:1000;U=stopandwait(a,P);semilogx(P,U,'r');holdonU=selective_reject(a,7,P);semilogx(P,U,'g');holdonU=gobackn(a,7,P);semilogx(P,U,'b');holdonU=selective_reject(a,127,P);semilogx(P,U,'k');holdonU=gobackn(a,127,P);semilogx(P,U,'y');ylabel('Utilization');xlabel('P');legend('Stop-and-wait','Go-back-Nwithw=7