Question

The distance from Earth to a distant planet is approximately 9×109m. What is the channel utilization if a stop-and-wait protocol is used for frame transmission on a 32 Mbps point-to-point link? Assume the frame size is 64 KB.

Answer 1

Answer:

0.266 %

Explanation:

Distance between Earth and distant planet = 9×10⁹ m

Data rate = 32 Mbps

Frame size = 64 KB = 512 Kbits

Propagation speed = Light speed = 3×10⁸ m/s

$\text{Transmission Delay}=\frac{\text{Packet Size}}{\text{Data rate}}\\\Rightarrow T_D=\frac{512}{32}=16\ ms\\\Rightarrow T_D=0.016\ s$

$\text{Propagation Delay}=\frac{\text{Distance}}{\text{Propagation speed}}\\\Rightarrow P_D=\frac{9\times 10^9}{3\times 10^8}\\\Rightarrow P_D=30\ s$

Channel utilization rate

$\text{Utillization}=\frac{T_D}{T_D+2P_D}\\\Rightarrow text{Utillization}=\frac{0.016}{0.016+2\times 30}\\\Rightarrow text{Utillization}=0.00266=0.266\%$

∴ The channel utilization if a stop-and-wait protocol is 0.266 %