計(jì)網(wǎng)實(shí)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.data link layer simulation實(shí)驗(yàn)名稱(chēng)：2.data link layer simulation1.實(shí)驗(yàn)容1.Draw Figure7.12 and 7.13.2.Simulation on Performance of Data Link Control ProtocolsUsing the same assumptions that are used for Figure 7.13 in Appendix 7A, plot line utilization as a function of P, the probabi

2、lity that a single frame is in error for the following error-control techniques:a. Stop-and-waitb. Go-back-N with w=7c. Go-back-N with w=127d. Selective reject with w=7e. Selective reject with w=127Do all of the preceding for the following values of a: 0.1,1, 10, 100. Draw con clusi ons about which

3、tech nique is appropriate for various ran ges of.2.實(shí)驗(yàn)結(jié)果J M4DD4D0>13*IO1'ttpHJJA=0.1&-S-5A=1MS.fl3 5A=10a=0.1時(shí)，W=7或者127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)，那么選擇拒絕和返回N都是一個(gè)分段函數(shù)a=100時(shí)，那么選擇拒絕和返回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;for j = 1:3for i = 1:le ngth(a) if W(j) >= 2*

4、a(i)+1 U(i) = 1;elseU(i) = W(j)/(2*a(i)+1); endend if j = 1W1 = U;endif j = 2W7 = U;endif j = 3W10 = U;endend plot(a,W1); hold on;plot(a,W7); plot(a,W10); set(gca,'xscale','log'); axis(0.1 1000 0 1);Figure7.13a = 0:0.1:1000;W = 1,7,127,127;P=10A(-3);for j = 1:4 for i = 1:length(a)if

5、W(j) =1U(i) = (1-P)/(1+2*a(i);endif W(j)=7 if W(2) >= 2*a(i)+1 U(i) = 1-P; elseU(i) = W(j)*(1-P)/(2*a(i)+1);endendif W(j)=127 if W(j) >= 2*a(i)+1U(i) = (1-P)/(1+2*a(i)*P); Y(i) = 1-P;elseU(i) = W(j)*(1-P)/(2*a(i)+1)*(1-P+W(j)*P); Y(i) = W(j)*(1-P)/(2*a(i)+1);endendif j = 1W1 = U;endif j = 2W7

6、= U;endif j = 3W10 = U;endif j = 4 W = Y;endend end plot(a,W1); hold on; plot(a,W7); plot(a,W10); plot(a,W); set(gca,'xscale','log'); axis(0.1 1000 0 1);2、 Drawfunction U=stopandwait(a,P)U=(1-P)./(1+2*a);endfunction U=selective_reject(a,W,P) U=(1-P).*(W>=2*a+1)+W.*(1-P)./(2.*a+1).

7、*(W<2*a+1);endfunction U=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); endfunction lab2_draw(a)P=0:0.1:1000;U=stopandwait(a,P);semilogx(P,U,'r');hold onU=selective_reject(a,7,P);semilogx(P,U,'g');hold onU=gobackn(a,7,P);semilogx(P,U,'b');hold on U=selective_reject(a,127,P); semilogx(P,U,'k'); hold on U=gobackn(a,127,P); semilogx(P,U,'y'); ylabel('Utilization') ; xlabel('P');legend('Stop-and-wait','Go-back-N with