Answer:
1. Arrival process
2. Service mechanism
3. Queue discipline
Step-by-step explanation:
Arrival Process
Arrivals may originate from one or several sources referred to as the calling population.
The calling population can be limited or 'unlimited'. An example of a limited calling
population may be that of a fixed number of machines that fail randomly. The arrival
process consists of describing how customers arrive to the system. If Ai is the interarrival time between the arrivals of the (i-1)th and ith customers, we shall denote the
mean (or expected) inter-arrival time by E(A) and call it (λ ); = 1/(E(A) the arrival
frequency.
Service Mechanism
The service mechanism of a queuing system is specified by the number of servers
(denoted by s), each server having its own queue or a common queue and the probability distribution of customer's service time. let Si be the service time of the ith customer, we
shall denote the mean service time of a customer by E(S) and µ = 1/(E(S) the service rate
of a server.
Queue Discipline
Discipline of a queuing system means the rule that a server uses to choose the next
customer from the queue (if any) when the server completes the service of the current
customer. Commonly used queue disciplines are:
FIFO - Customers are served on a first-in first-out basis.
LIFO - Customers are served in a last-in first-out manner.
Priority - Customers are served in order of their importance on the basis of their service
requirements.