||Due: Thursday, October 12, 2006
||Write a simulation program that simulates the behavior
of a queuing system that consists of a single queue with
finite capacity K and a single server. The arrival process
consists of two classes for customers (packets) say class
1 and class 2 or green and red. The arrival processes are
both Poisson distributed with parameters ë1 and ë2. The
service time is exponentially distributed with parameters
ì1 and ì2. There are two possible serving policies
- Threshold policy (with threshold B
< K )
When a class 1 customer arrives (e.g. high priority),
it is accommodated as long as there is enough buffer space,
i.e., as long as |x| < K where |x| is the number of
customers currently in the queue.
When a class 2 customer arrives (e.g. low priority), it
is accommodated only if the number of customers currently
in the queue does not exceed B, i.e., as long as |x| <
- Push-out Policy
When a class 2 (low priority) customer arrives, it is
accommodated if |x| < K.
When a class 1 (high priority) customer arrives, it is
accommodated at the end of the queue if |x| < K. However,
if |x| = K then, the last low priority customer from the
queue (if one is present) is removed and the new customer
is accommodated the at the tail of the queue.
- The parameters ë1, ë2, ì1, ì2.
- The Capacity of the queue
- If threshold policy is used then the threshold B.
- The sample path of the system (sequence of events with
their corresponding time).
- Also determine the average time that each class of customers
spends in the system as well as the number of lost customers
- Make a plot of the system average delay of each class
of customers as a function of the queue capacity for both
policies (for the threshold policy use various values
- What can you say about the average delay of the two
classes of customers. What would you do if you were responsible
for a switch that needed to handle data and voice packets.
Note that in general data packets are not considered delay
sensitive. On the other hand the quality of voice calls
drops as delay increases.