[Asterisk-biz] voip termination deployment models

[alex at pilosoft.com]

On Wed, 27 Apr 2005, Jon Lobley wrote:

> Is SER more appropriate as an intermediary proxy with asterisk at the
> core, or is SER at the core with Asterisk providing supplimentary
> services such as VM & IVR more common?
Let's reformulate the question in more proper terms: Using Asterisk as
Media Gateway (the actual gatewaying TDM-VoIP) and using Asterisk as Media 
Gateway Controller (the "proxy" that controls the MG).

Asterisk *can* serve as MG. However, the density still is somewhat weak,
and it may take quite a bit of work to make Asterisk handle lots of
concurrent calls without problems (I'm taking dozens of spans).  
Comparatively, used TNT or AS53xxx does job for about the same money but
less headache. Since MG is a 'dumb' device (controlled by MGC), you don't
lose much by using a proprietary solution.

With regard to MGC, it is also a big question whether Asterisk is 
appropriate. Keep in mind, Asterisk SIP stack wasn't designed to be a 
proxy, it is still a B2BUA at heart. (Recent SIPP work notwithstanding). 

With SIPP, you can sort of use Asterisk as a MGC/proxy, but ser has
performance an order of magnitude higher (of course, ser doesn't have as
many features as Asterisk).

Asterisk really shines as a feature server, and that's I think where it 
belongs at this point. 

Our architecture is TNT's and AS53xx as MG, ser as MGC, Asterisk as a 
voicemail/other feature server. 

-alex