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How much blocking?

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How much blocking will a trunk group cause if it is engineered with 10 lines and is offered 8 Erlangs of traffic during its busy hour?

 

An example calculation

An example calculation

 

To find the answer to this question, follow the following steps:

 

Select the Erlang B Calculator using the Tab Control at the top of the window.
Click with your mouse on the radio button marked Unknown which is in the Blocking section of the calculator. This indicates that it is the blocking variable which you wish to calculate.
Enter the figure 10 into the edit box in the Lines section of the calculator.
Enter the figure 8 into the edit box in the B.H.T. section of the calculator.
Press the Calculate button.

 

After a short time, the figure 0.122 will be displayed in the Blocking edit box indicating that if this trunk group is engineered with 10 lines and is offered a traffic level of 10 Erlangs during its busy hour, a blocking figure of 0.122 will be experienced. That is, 12.2% of calls will be blocked if the assumptions associated with the Erlang B traffic model are met.