asterisk users - Nov 2007 - Asterisk on Zonbu, impact of transcoding

Zonbu.com sells a little box I was planning to use as a router, but I 
couldn't resist putting Asterisk on it just for fun. It may never see its 
intended purpose.

The box costs US$249 (and was delivered 40 hours after being orderd!), but 
you can get it for less if you subscribe to their service. I didn't.

The box is an Intel compatible processor (VIA Esther processor 1200MHz) 
with 512mb ram and 4gb of cf for storage. It's silent because it has no 
moving parts.

I installed CentOS 5.0, Asterisk 1.2.24, and Zaptel 1.2.21.

I started loading up calls using this call file from my dev box (P4 
1.6ghz, 640mb ram):

 	channel:        sip/zonbu0/760xxxxxxx
 	application:    record
 	data:           /tmp/test.wav
 	maxretries:     0

My dialplan (on zonbu0) consisted of:

         exten = _x.,1,                 
verbose(1,${CONTEXT}:${EXTEN}:${PRIORITY})
         exten = _x.,n,                  playback(demo-congrats)
         exten = _x.,n,                  goto(1)

I loaded 20 calls. "top" said Asterisk (on Zonbu0) was consuming 20%
of
the CPU. I placed a test call from a SIP phone -- sounded fine to me.

I loaded 100 calls. "top" said Asterisk was consuming 99% of the CPU.
I
placed a test call -- still sounded fine.

I loaded 115 calls. Sound quality was very choppy.

I "soxed" demo-congrats.gsm to demo-congrats.ul.

I loaded 100 calls "top" said Asterisk was consuming 20% of the CPU.

I loaded 180 calls. "top" said Asterisk was consuming 35% of the CPU. 
Sound is still fine.

I loaded 197 calls. Something was overloaded. My dev box was 
non-responsive and the Zonbu wouldn't answer any more calls.

I'm impressed with how much load this box handled and the impact of 
eliminating the transcoding.

Thanks in advance,
------------------------------------------------------------------------
Steve Edwards      sedwards at sedwards.com      Voice: +1-760-468-3867 PST
Newline                                             Fax: +1-760-731-3000

> I'm impressed with how much load this box handled and the impact of
> eliminating the transcoding.
> 
> Thanks in advance,
> ------------------------------------------------------------------------
> Steve Edwards      sedwards at sedwards.com      Voice: +1-760-468-3867 PST
> Newline                                             Fax: +1-760-731-3000
Steve,

Thank you very much for the analysis.  This would be great to add to the
wiki under dimensioning or server hardware (I forget my login and it's not
on the sticky note under my keyboard).

I have some experience with VIA embedded devices and running Asterisk on
them, and you are correct with the transcoding, do as little as possible, as
it eats up CPU.  The price on this device is a bit under what you could
build the unit for, so all-in-all Zonbu looks like a good deal.  I'm sure
they are getting volume discounts from their suppliers.  Zonbu running
AstLinux would make for a SOHO SMB SIP PBX market killer.  Hmmmmm very
interesting........says the mad scientist.

JR
---
JR Richardson
Engineering for the Masses