[asterisk-users] Asterisk on Zonbu, impact of transcoding

[Steve Edwards]

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