It is required to design a communication link running from A to B. The link parameters are as follows: - Distance, d = 1000 km with a propagation delay of 5 micro seconds per km - The frame size, F, is equal to 3000 bits - Sliding window protocol with W = 7. - The link bit rate R b/s is to be determined/designed.

a) Plot the link utilization as a function of the link transmission rate R. Identify the transmission bit rate R* where the link utilization is less than 100% for rates greater than R*.

b) Plot the link throughput in frames per second.

c) Compute the maximum possible throughput (in frames per second) of such link for the above given parameters.

d) Specify the changes in the design required to increase the maximum throughput of such a link.