[Asterisk-Users] Question about AGI vs. FastAGI vs. straight C/DB development

[Steven Critchfield]

On Mon, 2005-03-07 at 14:21 -0800, beonice wrote:
> Folks,
> 
> I want to build a custom IVR for my setup. I've got it
> working (well, the bells and whistles are not there
> yet, but the basic stuff works) using AGI, but I'm
> worried about how well this will scale.
> 
> I've seen references to FastAGI, and presumably this
> will be more efficient. 
> 
> Question, though: how well do either of these (AGI or
> FastAGI) scale if my system is handling a large number
> of simultaneous calls? I'm assuming that even with
> FastAGI, there's going to be some CPU overhead that
> will increase as the number of simultaneous calls
> increases. 
> 
> Would it make more sense to write a custom application
> in C instead, designing it to work sort-of like the
> built-in app_voicemail.c and others? I do know C, but
> is it worth the effort in terms of ROI? :) 
> 
> I'd like to figure this out in advance rather than
> after all my customers (hopefully there _will_ be
> customers) start yelling at me about performance
> issues. :)

You said a magic word there, customers. You need to become versed in the
ins and outs of licensing. If you write it in C and distribute it, you
must also offer to those you distribute asterisk your modifications and
linked in code.

For AGI and FastAGI, it isn't linked to GPL code in asterisk and
therefore is sheltered from the GPL license of asterisk. But then you
need to verify you aren't using any libraries that are distributed under
a GPL license or you would also have to open source your code upon
distribution.

FastAGI offers faster initial response times than AGI as it will most
likely already be running and ready to accept a new call. FastAGI should
also be capable of being load balanced if that process is doing too much
work to be responsive upon scaling. AGI is not capable of being run from
a different machine.

 
-- 
Steven Critchfield <critch at basesys.com>