Engset loss - compulsory test

Consider an M/M/2/2/4 Engset systems. Let lambda=0.5 and mu=1.

a) Assume that the system is idle. What is the expected time until the next request arrival? Motivate your answer.

b) Draw the Markov chain of the system, calculate the state probabilities in steady state.

c) Calculate the time blocking probability and the call blocking probability.

d) Calculate the average number of customers in the system.