Usage

To use the Port Estimator:

1. Type in your expected Call Arrival Rate, and Average Call Duration.
2. Click Recalculate.
3. Scroll down to view the table.

This simple port capacity estimator uses an Erlang B queueing model (M/M/k/1) to estimate the number of ports needed to support a given quality of service.

The Erlang B model assumes:

• The Call Arrival Rate is Poisson distributed.
• The Service Rate (Average Call Duration) is exponentially distributed.
• The Number of Callers is much larger than the number of ports.
• When a caller finds all ports in use (busy signal), the caller hangs up and does not redial. (There is no queue).

Call arrival rate		calls/hour
Average call duration		seconds/call
Number of ports
Busy signals		% of callers turned away

Call Arrival Rate	Average Call Duration	Ports	Callers Turned Away
(calls/hour)	(seconds)		(%)