[Asterisk-Users] 5,000 concurrent calls system rollout question

[C F]

On 1/31/06, Damon Estep <damon at suburbanbroadband.net> wrote:
>
>
> > -----Original Message-----
> > From: asterisk-users-bounces at lists.digium.com [mailto:asterisk-users-
> > bounces at lists.digium.com] On Behalf Of C F
> > Sent: Tuesday, January 31, 2006 4:03 PM
> > To: Asterisk Users Mailing List - Non-Commercial Discussion
> > Subject: Re: [Asterisk-Users] 5,000 concurrent calls system rollout
> > question
> >
> > I don't know how much 1+1 by you is, but lets recalculate this for a
> > moment:
> > First the bandwidth per channel:
> > http://www.airewaves.com/aire/support/bandwidth_explain.php
> > 1.5mbps (mega *BITS* not BYTES per second) to a full T1, which equals
> > 1536 Kbits, each channel then takes 64kbps.
> > 64*5,000=320,000kbps.
> > 32,000/1,024=312.5 Mbps (round off to Mbps), no where close to a Gb.
> > Every single PC made in the last 4 years I came across, can handle
> > this type of bandwidth.
> > BTW, this all amounts to just over 39 MBYTES per second.
> 312.5/8=39.0625
> >
>
> Not that I disagree with your point, the bandwidth is not huge, but the
> math is a little fuzzy;

No it's not, the math was meant for the T1 calculations, reread the
post I replied to.

>
> First of all, a g.711u stream over UDP is closer 80k than 64k, the
> payload is 64k + udp overhead + IP overhead.
>
> Now consider that the call is originated as SIP (llok back a few days in
> the thread), and lets assume the call goes to an external hard or
> softphone, and lets also assume that there is a reason to keep the RTP
> stream running through asterisk (monitoring, recording, transferring,
> dtmf, ability to re-enter IVR, etc).
>
> I make all the assumptions safely since the thread was started by
> someone looking to set up a large call center and I have followed thread
> out of curiosity.
>
> So a 80k full duplex RTP stream originates on media gateway somewhere,
> hits the asterisk box, is internally bridged, and is sent back out to a
> phone somewhere. My math says this puts a 160kbps full duplex load in
> the NIC.
>
> Ok, now lets go for 5000 of them. 160kbps*5000=800000kbps or 800mbps -
> full duplex.
>
> Have you ever seen a NIC or switch that can run GigE full duplex at 80%
> utilization and not at least start to fall apart?
>
> To get to a comfortable load you would need 2x GigE NICs (for ~40%
> utilization), of course now we are adding additional overhead for the
> bonded NIC trunking protocol.
>
> Is still contend this is not practical without multiple very high end
> servers and round robin call origination from the upstream provider
> delivered over something like GigE or OCx.
>
> Maybe someone will step up and post some real-world application limits
> based on experience...
>
>
>
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>
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>
>
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