Poisson

Poisson is the simplest traffic model and is used to work out how many lines are required if the traffic figure (in Erlang) during the busiest hour is known. The Poisson distribution is based on the following assumptions:

• Calls are served in random order. 
• There are an infinite number of sources. 
• Blocked calls are held. 
• Holding time is exponential or constant.

The usage of Poisson in ForecastX™ is similar to Erlang B. See below for information on Erlang B.

To use the Poisson forecasting technique:

1. Click the Forecast Method tab.
2. From the Forecast Technique menu, scroll through the list of methods and select Poisson. The Poisson Forecasting technique appears.
   
3. Enable the Edit Parameters checkbox to activate Poisson’s parameters. 
4. In the Compute Type section, select either N to A, or A to N. 
5. In the Lost Possibility section, select one of the options for the percentage of loss that is possible. 
6. Click Finish.