asterisk users - Dec 2006 - Bandwidth requirements for 1, 000, 000 minutes a month

This may expose my ignorance, but here goes :)

I've been asked to figure out how much bandwidth would be needed to handle 
1,000,000 minutes a month.

Here's the environment:

) All calls are received via SIP.

) All calls use the ulaw codec.

) Calls average 10 minutes in duration.

) The "busiest" hour will account for 10% of the daily total.

This is how I'm figuring it...

Casual observation shows that SIP setup and teardown takes about 26 UDP 
packets. Assuming the packets are full (512 bytes) this adds up to about 
13 kilo-bytes for each call.

I've heard that ulaw (including overhead) is supposed to take about 80 
kilo-bits/sec.

Assuming each call takes 10 minutes, each call will take 13 kilo-bytes + 
(80 kilo-bits * 60 * 10) or 48.13 mega-bits. Assuming (to make the math 
easier) 10 bits = 1 byte, each call will take 4.813 mega-bytes.

So, 100,000 calls of 10 minutes (1 million minutes) would consume 481,300 
mega-bytes per month or 3,333 calls consuming 16,043 mega-bytes per day.

Assuming the busiest hour accounts for about 10% of the daily total, that 
hour would consist of 333 calls consuming 1,604 mega-bytes.

So, my "peak" would need 4.5 mega-bits per second of bandwidth.

Am I in the ballpark?

Would anybody venture an estimate of what the peak bandwidth would be if 
we changed to IAX? With trunking?

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

But who in there right state if mind would use ulaw?
Just take them away to the funny farm ha ha ho ho!! :-P

gsm, ilbc, g729 etc are a lot better choice.

Best regards,

Al Bochter
Bochter Services
http://www.BochterServices.com/?t=Email

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Steve Edwards wrote:
> This may expose my ignorance, but here goes :)
>
> I've been asked to figure out how much bandwidth would be needed to 
> handle 1,000,000 minutes a month.
>
> Here's the environment:
>
> ) All calls are received via SIP.
>
> ) All calls use the ulaw codec.
>
> ) Calls average 10 minutes in duration.
>
> ) The "busiest" hour will account for 10% of the daily total.
>
> This is how I'm figuring it...
>
> Casual observation shows that SIP setup and teardown takes about 26 
> UDP packets. Assuming the packets are full (512 bytes) this adds up to 
> about 13 kilo-bytes for each call.
>
> I've heard that ulaw (including overhead) is supposed to take about 80 
> kilo-bits/sec.
>
> Assuming each call takes 10 minutes, each call will take 13 kilo-bytes 
> + (80 kilo-bits * 60 * 10) or 48.13 mega-bits. Assuming (to make the 
> math easier) 10 bits = 1 byte, each call will take 4.813 mega-bytes.
>
> So, 100,000 calls of 10 minutes (1 million minutes) would consume 
> 481,300 mega-bytes per month or 3,333 calls consuming 16,043 
> mega-bytes per day.
>
> Assuming the busiest hour accounts for about 10% of the daily total, 
> that hour would consist of 333 calls consuming 1,604 mega-bytes.
>
> So, my "peak" would need 4.5 mega-bits per second of bandwidth.
>
> Am I in the ballpark?
>
> Would anybody venture an estimate of what the peak bandwidth would be 
> if we changed to IAX? With trunking?
>
> Thanks in advance,
> ------------------------------------------------------------------------
> Steve Edwards      sedwards@sedwards.com      Voice: +1-760-468-3867 PST
> Newline                                             Fax: +1-760-731-3000
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> Inbound (clean). Database: 0659-0, 12/15/2006 - 12/15/2006 9:47:48 PM
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>

> So, my "peak" would need 4.5 mega-bits per second of bandwidth.
> Am I in the ballpark?
Sounds about right. Or the other way around (if you need to know the
peak bandwidth usage):

For audio:

1,000,000 minutes/month = 33,000 minutes/day
10% daily usage in 1 hour = 3,300 minutes used
3,300 minutes used in 60 minutes = 55 concurrent calls

80 kbps / 1 call direction * 55 calls = 4.4 Mbps per direction

Assuming full duplex audio, you need 4.4 Mbps in + 4.4 Mbps out per
call leg. If you route the call so each packet comes in and goes out
the network (2 call legs), then double the bandwidth.

I guess adding 0.1 Mbps for call setup and tear down is safe.

--Luki