[asterisk-biz] Outbound Messaging, Voice Broadcasting, Alerts,

[Gerard Hickey]

On Aug 7, 2007, at 1:41 AM, Luki wrote:

>> Does anyone know of a program/code out there for high volume voice
>> broadcasting, the applications include high volume political calling,
>> outbound surveys, emergency notifications, patient reminders, etc,  
>> etc.
>> Looking for a program that can handle small volumes of calls,  
>> example 50
>> to 200 calls for doctors offices to very large call volumes of
>> 1,000,0000 calls per hour for mass messaging.
>
> For a project like this, a distributed solution would be ideal. You
> know, Google-style: lots of low-end machines, cheaper and redundancy
> included. With Asterisk you probably can't squeeze more than 250 calls
> even on a decent hardware, and for 1,000,000 calls per hour, say 2
> minutes in duration (with call setup), you need about 130 decent
> machines. Or like 300 low-end ones... so like 8 racks full.
>
> The code should be pretty simple (this setup is easily distributable).
> One beefy database server (or a small cluster for redundancy) can
> handle ~500-1000 queries/sec you'd need to sustain for 1,000,000 calls
> per hour.

Yes, you definitely need to have a distributed solution to scale up  
to the 1M calls/hour, but the architecture is much more complex than  
you first might think it is.

First you need to have a set of machines as directors to keep track  
of what machines have outdial capabilities. Using a director approach  
allows one to have better control of the systems and receive up to  
the minute reporting concerning the efficiency of the cluster of  
asterisk machines. Arguably you could reverse the solution and have  
the individual asterisk boxes query the database when it has  
capability to place a call, but it is easy to have two or more  
asterisk boxes attempting to dial the same number. You also have the  
problem of not detecting asterisk boxes that are not pulling their  
own weight as easily.

The bigger problem is call scheduling. Your queueing system gets very  
complex very fast when you start servicing multiple clients with  
different requirements and different workloads. Lets take the  
examples from the first email: a doctor's office placing patient  
reminders and a political campaign. Everything is great when the  
system is processing the patient reminders because the system is  
lightly loaded. Then the political campaign starts and the system  
gets flooded with thousands of calls (seems to me that 1M calls is a  
bit much unless you are doing national political campaigns). As the  
campaign calls take over the system, one will find that without the  
proper queuing algorithms the patient reminders are now being placed  
2 days after the appointments.

Finally, blacklists and do not call lists need to be incorporated  
into the system. If  I remember correctly there are a number of  
federal regulations concerning automated calling that also need to be  
addressed in the system along with observing time of day restrictions  
for the destination number.

All in all the solution gets pretty complex pretty fast. Unless you  
do a hack job, just don't care and have not problem treating your  
customers like dirt. Then you have it made.
--
Gerard Hickey                             Kinetic Compute Services
hickey at kinetic-compute.com                694 Allen Ave.
207-318-5646                              Portland, ME   04103-3707

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