Assumptions in Queuing system:
• Flow balance implies that the number of arrivals in an observation period is equal to the number of completions in the same period (λ = X)
• One step behavior asserts that no two jobs in the system "change state" (i.e., finish processing at some device or arrive to the system) at exactly the same time
• Homogeneity means that the average job-arrival rate and the average service rate are independent of the system’s state. Furthermore the probability of moving between two servers is independent of the numbers of jobs at the source and destination servers. Unlike the other two assumptions, violating the homogeneity assumptions introduces considerable error in the calculations.