Consider the E2/M/1 model with  4 and  5. This model can be formulated as a continuous time Markov chain by dividing each interarrival time into two consecutive phases, each having an exponential distribution with a mean of 1/(2) 0.125, and then defining the state of the system as (n, p), where n is the number of customers in the system (n 0, 1, 2, . . .) and p indicates the phase of the next arrival (not yet in the system) ( p 1, 2).

Construct the corresponding rate diagram (but do not solve further).