Question

Question 3 Link Utilization (15 points) For a Ikm wired link, the data rate is 12Mbits/s and an idle AQR scheme is adopted. 1) If packets are sent in the size of N 2048 bits, calculate the link utilization efficiency where P, 1.1 x 10 2) Assume chanel becomes better resulting in a P, 1 x 10-6. To keep the same link utilization, how can you adjust the data rate, Ri, while keeping the packet length, N, as the same

Answer 1

$\eta$=T/B

TRANSMISSION SPEED (T)=DATA SIZE(N) / RTT

N=2048

PD=1.1*10^-6

RTT=2*PD=2.2*10^-6

T=2048 / 2.2*10^-6=931 MBPS

$\eta$=931*10^6 / 12*10^6 = 77.5 ANS

2)

NOW RTT=2*10^-6

T=2048/ 2*10^-6=1024 MBPS

77.5=1024*10^6 / B

B=13.21 MBPS ANS