ExtErlBLines()

This function estimates the number of lines required in a trunk group if the offered traffic is known.

Format

=ExtErlBLines (Traffic,Blocking,Recall)

Result

A positive integer or zero.

Arguments

Name	Description	Units	Limits
Traffic	The busy hour traffic	Erlangs	Between 0 and 90,000
Blocking	The ratio of calls offered to a trunk group that can be blocked	(Unitless)	Between 0.001 and 0.500
Recall	The percentage of calls that are immediately retried if blocking is encountered	(Unitless)	Between 0 and 95

Example

To estimate how the lines are required for 100 Erlangs at 0.010 (1%) blocking, assuming that 20% of blocked calls are immediately retried, enter:

=ExtErlBLines(100,0.010,20)

The answer should be 118