 This topic has 3 replies, 1 voice, and was last updated 19 years, 5 months ago by Teresa Ovalles.

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Prakarn KorkiatcharoonGuest
I am working with International Telephone Provider in Thailand. We use software “Metrica NPR, Kingfisher”, to create and analyze Traffic Report of the exchange.
In generate the traffic report, I found one function that can find “Offered Traffic ( Erlang )” by enter “Number of Available Circuit” and “Carried Traffic ( Erlang )” like this:
1.) Offered Traffic = function of ( Number of Available Circuit , Carried Traffic )
But usually, we use difference formula to figure out Offered Traffic as below:
2.) Offered Traffic = Carried Traffic / ( 1 – Blocking factor )
and it get a different out come, that I don’t know how to explain. ( Before that, we use the second formula )
Therefore, please explain how function “Offered Traffic” working and how to apply to an application? What is a Traffic Engineering Concept that this function refered.
Thank you forward for your help, look forward to hearing from you soon.
Yours sincerely,
Prakarn KorkiatcharoonAzhar RusliGuestLooking on the Offered Traffic function stated by the traffic report generation which is Offered Traffic=function of (No. of Available Cct, Carried Traffic) I guess this should refer to the Erlang’s lostcall formula which refers to the call congestion. B, prob. of congestion=(A^N/N!)/(1+(A^1/1!)+(A^2/2!)+…….+(A^N/N!)) where A=Carried Traffc N=Number of circuit Therefore Off. Traff=Carr. Traff/(1B)
The different outcome, I guess would be due to the pactorial function in the formula.
Regards & Thank you,
Azhar.Justin StrongGuestI’m replying to the last article and the formula mentioned for calculating offered traffic only took into consideration No. of Available Cct and Carried Traffic. This formula only works if your offered traffic is less than the total capacity of your trunk group (or whatever is carrying your traffic). To accurately assess offered traffic you need to know how many calls could not complete due to insufficient capacity (e.g. overflows).
I’m going from memory here but if I recall correctly a standard formula is Carried_Traffic / (1 – (overflow/attempts)).
Justin.
Teresa OvallesGuestI use software ‘SwitchMate’ and I have of follow problem analizing a trunk:
For example:
Carried Traffic=10.2167 erlang
Percent Block=0.23%
Circuit Available=24
Offered Traffic=10.2167 erlangWhile, for another way I get that results (I was using this formula:Carried Traffic/1Percent Block): 10.24 erlang
And with this formula:
B=(A^N/N!)/(1+(A^1/1!)+(A^2/2!)+…….+(A^N/N!))
Offered Traffic=Carried Traffic/(1B)=10.3040
Please, help me, I am very confuse.
Thank you forward for your help,
Regards & thank you,Teresa

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