[Asterisk-Users] IVR and db

[Jean-Michel Hiver]

>I am not sure to understand your question. Why on earth do you need 240 
>channels for 1,000 calls an hour? How long is each call projected to be?
>
>20 minutes (makes with 2 QUAD E1, 240*3 = 720 calls/hour)
>  
>
Wow, so you expect your busiest hour traffic (BHT) to be in the order of 
1,000 calls of 20 minutes each, that is 333 hours and 20 minutes?

If so, you should consider (according to erlang calculations) around 400 
circuits, that is more than 10 E1 capacity.

I thought there was 5,000 employees worldwide; are you sure about this 
evaluation? It seems such a monstruous capacity compared with the amount 
of users needed.

At any rate, in this case I would make a 1 E1 PC prototype (each server 
being around $2k including E1 card) and then clone it as many time as 
necessary. Have a separate DB server to store the results. Clone the PC 
as many times as required and hook all of this up on a LAN.

I don't think much - other than hardware failure, which can be monitored 
- can go wrong with this setup in terms of dimensioning. Just add as 
many boxes as required. And once you have your first prototype working, 
it is very easy to duplicate it. Just use mondo or some other backup / 
restore tool...

Cheers,
Jean-Michel.



>  
>
>>Cluster ? DNS ? Anyhow the voices playback can only be done on the maschine
>>having the E1 cards connected I suppose ?
>> 
>>
>>    
>>
>Well, you could have a dedicated CPE gateway and do everything through 
>IP. Considering it's a "one time" survey, I would argue it would be 
>faster and cheaper to have a toll free DID forwared from NuFone to your 
>asterisk box - especially if you're prototyping.
>
>5,000 employees survey = 5,000 phones calls, 5 minutes each, at 0.02 per 
>minute, comes to $500 plus bandwith costs. Compare that with the price 
>of a PRI, including PRI cards and such...
>
>If you go for PRI lines, then you don't even need to cluster - I was 
>thinking "VoIP setup" there. Just have 1 PC per E1 and a common database 
>server, it should work fine. I do not think Asterisk will have any 
>issues handling 30 simultaneous calls (i.e. 1 E1) - even with AGI 
>processing - on decent PC hardware.
>
>4 PC's :(
>
>How many channels are you planning for? From what you said I would plan 
>for 2 E1s. Provided you use these newer cards with hardware echo cancel, 
>and don't do fancy transcoding, I would assume that you might not even 
>need multiple boxes since the CPU usage shouldn't be so high...
>
>According to the voip-info.org litterature, the two CPU hungry things are:
>
>1/ Transcoding
>2/ Echo cancellation
>
>So... with decent hardware I would argue you should be just fine... no 
>warranties given though. If you want to be sure that your system is 
>correctly dimensioned first time you probably should write down some 
>specs and ask Digium to sell you a turn key system which will Just Work...
>
>Cheers,
>Jean-Michel.
>
>
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