The most important notation that summarizes a queue:
• ρ: utilization ratio = λ / μ
Examples:
• ρ = 1 means the arrival rate is equal to the service rate; the queue is staying the same size.
• ρ > 1 means the arrival rate is greater than the service rate; the queue is getting larger.
• ρ < 1 means the arrival rate is less than the service rate; the queue is getting smaller.
