Erlang

- Free Erlang Calculator English version

Download Erlang Calculator Ver2.2Dec. 12, 2007 Erlang Calculator is a tabbed calculator that includes Erlang B, Extended Erlang B and Erlang C traffic calculators for dimensioning telecommunications trunk groups, calculating Voice over IP bandwidth and estimating staffing requirements of a call center. *Erlang B is a formula for blocking no retrial sources. *Extended Erlang B is a formula for blocking retrial sources. *Erlang C is delay formula for queueing infinite sources.

***Erlang B calculator Ver4.0**Nov. 8, 2007 Erlang B is a formula for blocking no retrial sources. High speed Erlang B calculator, calculate Probability of blocking, Lines(Number of servers), Traffic mutually by Erlang B Formula. Lines and Traffic can set more than 10,000,000. Erlang B Formula B = (a^n/n!)/(1+a/1!+a^2/2!+a^3/3!+...+a^n/n!) B:Probability of blocking a:Traffic n:Lines(Number of servers)***Extended Erlang B calculator Ver2.1**Dec. 12, 2007 Extended Erlang B is a formula for blocking retrial sources. Extended Erlang B calculator, calculate Probability of blocking, Lines(Number of servers), Traffic mutually by Extended Erlang B. Lines and Traffic can set more than 10,000,000, but large number calculation will need long time. ERL-B:Probability of blocking by Erlang B ERL-B(a,n) a:Traffic n:Lines Be:Blocked Erlangs Be=a*ERL-B(a,n) C:Carried Traffic C=a-Be=a*(1-ERL-B(a,n)) R:Recall Traffic R=Be*r r:Recall factor B:Overflow Traffic B=Be*(1-r) a:Traffic a=ao+R C+B -> =ao:Initial Traffic(Offerd Load) C+B=a-Be+Be*(1-r)=a-Be*r=a-a*ERL-B(a,n)*r =a*(1-ERL-B(a,n)*r) Calculate a:Traffic which is satisfy C+B=a*(1-ERL-B(a,n)*r) -> =ao. At that ERL-B(a,n) is Extended Erlang B Probability of blocking. Erlang B Formula B = (a^n/n!)/(1+a/1!+a^2/2!+a^3/3!+...+a^n/n!) B:Probability of blocking a:Traffic n:Lines(Number of servers)***Erlang C calculator Ver2.1**Nov. 11, 2007 Erlang C is delay formula for queueing infinite sources. Erlang C calculator, calculate Probability of a Delay>0, Lines(Number of servers), Traffic mutually. In addition, calculate Wq:Average wait time in queue, Lq:Average number of callers in queue, P(>T):Probability of a Delay>T mutually. Lines and Traffic can set less than 500,000,000. P(>0):Probability of a Delay>0 P(>0) = (a^n/n!)*n/(n-a)/((1+a/1!+a^2/2!+a^3/3!+©¥+a^(n-1)/(n-1)!)+(a^n/n!)*n/(n-a)) = 1/((n-a)/n*(n/a+n*(n-1)/a^2+...+n*(n-1)*...2/a^(n-1)+n!/a^n)+1) Wq:Average wait time in queue =P(0>)*h/(n-a) Lq:Average number of callers in queue =P(0>)*a/(n-a) P(>T):Probability of a Delay>T =P(>0)*e^(-(n-a)*T/h) h:Average call time