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  • #33265
    Eddie M

    I am assessing the suitability of CPE equipment for our business. The vendors quote BHCC (Busy Hour Call Connections) and BHCA (Busy Hour Call Attempts) in their literature. I was wondering whether someone knew how these figures are calculated?
    What I would like to do is workout these figures for our current business and and then compare “apples with apples” with the vendors figures

    Francois Rust

    I certainly dont know how these figures are calculated, but the actual application on the switch will have an impact on the figure, i.e. :- Analog, Digital, ISDN, CTI, ETC..
    I have a question. BHCA = BHCC x 3
    Does this rule still apply?

    Jeff Coomans

    Typically, these figures can be misleading. Often, they are calculated under the best of circumstances (i.e. the PBX is equipped with the fastest processor, maximum number of DTMF receivers, and largest amount of memory), and may not reflect your configuration. However, generally, they are a means of evaluating the pure call processing horsepower that the switch can provide. BHCA simply refers to the number of calls that the system is capable of processing in it’s busiest hour of traffic, while BHCC refers to the number of calls that the system is capable of terminating under this busy hour load. Unless you’re a call center, hospital, or municipality, most PBXs from the major manufacturers (i.e. Nortel, Avaya, NEC, etc.) are more than adaquate at processing the average office call load. Purists may disagree, but these statistics are often secondary buying decisions. I’d only worry about it if you’re in a particularly heavy calling environment.

    Joe Golden

    As I recall, CA includes all call events that impact processor real-time. The major category is all actions required for the successfully completed call. The smaller components of CA would be mis-dial, abandoned calls, etc.

    Another related topic is how real-time is assigned to a “call”. RT/ call varies with call type. A simple desk-desk call type without billing and other features would have the smallest RT demand. A call going over IXC trunk and requiring billing and other features actions would require more RT. RT is generally expressed in milliseconds/ call

    Switch suppliers generally state their CA capacity by :Call Mix”: 50% POTS/ 50% Business”

    Telcordias’ model for call capacity is:

    [(3.6 M millisec/hour) * (max. % processor occupancy)]/(millisecond/call


    Regarding BHCA and BHCC Can somebody help me understand the relationship of this metrics with the effective traffic in Erlangs carried in the Network during the busy hour?

Viewing 5 posts - 1 through 5 (of 5 total)
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