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Erlang traffic models

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The calculations performed by CC-Excel are based on the Erlang traffic models developed in the first half of the last century. Two models are used:

 

The Erlang C traffic model is used for estimating call handling performance where calls are queued and makes the following assumptions:

 

       Calls are offered randomly to a queue (Poisson arrivals).

       Users wait if they find the system busy.

       Service times are exponential.

       Users are served in the order of arrival.

       Users are directed to the first available server (agent).

       Queue sizes are unlimited.

 

The Erlang B traffic model is used for estimating the number of lines required into a call centre facility and makes the following assumptions:

 

       Calls are presented randomly to a trunk group (Poisson arrivals).

       Call times are fixed or are exponentially distributed.

       Blocked calls are cleared.

 

See also

 

Important notice