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18th September 1999 at 16:02 #32466Prakarn 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.
Prakarn Korkiatcharoon24th September 1999 at 16:02 #32467Azhar RusliGuest
Looking 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 lost-call 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/(1-B)
The different outcome, I guess would be due to the pactorial function in the formula.
Regards & Thank you,
Azhar.6th December 1999 at 16:03 #32468Justin StrongGuest
I’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.23rd January 2001 at 16:41 #32469Teresa OvallesGuest
I use software ‘SwitchMate’ and I have of follow problem analizing a trunk:
Carried Traffic=10.2167 erlang
Offered Traffic=10.2167 erlang
While, for another way I get that results (I was using this formula:Carried Traffic/1-Percent Block): 10.24 erlang
And with this formula:
Offered Traffic=Carried Traffic/(1-B)=10.3040
Please, help me, I am very confuse.
Thank you forward for your help,
Regards & thank you,