[Asterisk-Users] 2 4-port T1 cards

[Vincent Choy]

How many simultaneous "sound" channels could the * system operate in a dual
T400P. Is this dependant on the sound card and its' drivers? Would one
require a higher CPU spec? (From my understanding,  onboard sound cards can
also increase CPU load whereas dedicated sound cards like Live/Audilogy take
most of the load.)



----- Original Message ----- 
From: "Mark Spencer" <markster at digium.com>
To: <asterisk-users at lists.digium.com>
Sent: Wednesday, May 28, 2003 2:38 PM
Subject: Re: [Asterisk-Users] 2 4-port T1 cards


> > 3. Dual MB won't help much in pure telephony.
> > In pure telephony, you are basically dealing with serial line
> > IO. A T1 is little more than I long distance serial line. 8 T1s
> > is just 11.7megs per second each way, or 23.4 megs in and out.
> > Not too much for a good machine to do. Granted, if you are doing VoIP
> > then you add another set of ins and outs with compression in the middle
> > of it too. This is where the second CPU comes in handy.
>
> Actually, with Zaptel, and the T400P especially, dual CPU makes a *big*
> difference.  The T400P and E400P are slave-only designs, so the CPU spends
> a lot of time just cramming I/O down the PCI bus.  Having a second CPU
> free to do work will definitely help.
>
> > 4. AGP Video.
> > Make sure not to use the frame buffer, it has been reported that the
> > frame buffer generates large amounts of interupts and will
> > degrade the performance.
>
> Don't underestimate this effect or think that a fast CPU will get around
> it.  frame buffer is a definite no-no because it disables interrupts
> during screen redraws which take an enormous amount of time.  If your call
> quality drops while you're playing quake on your PBX, don't come crying to
> us ;-)
>
> Mark
>
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