[asterisk-users] Hardware advice for 100 extensions, routing via ISDN

[Gordon Henderson]

On Sun, 5 Aug 2007, Rory Campbell-Lange wrote:

> In the O'Reilly Asterisk book it suggests that it is important to allow
> BIOS specification of the PCI slot IRQs -- the Tyan won't let us do that
> I don't think. Is this an issue with the Sangoma card?

Probably not. Once the system is built, have a a look at /proc/interrupts 
to see what's on what. Sometimes moving a card into a different PCI slot 
helps.

Turn off *ALL* unused hardware in the BIOS. Eg. Serial ports, printer, 
on-board sound, 2nd Ethernet port (if possible), and so on.

> Also comments about how suitable this machine is would also be
> gratefully received.

If you root around the inteweb, you'll find success stories of people 
running more than 100 SIP extensions on much lesser hardware - eg. on a 
1Ghz Via type motherboard. One site by our very own Tzafrir Cohen has some 
excellent data on it - see
   http://www.xorcom.com/support/xorcom_ts_1/test_results_for_xorcom_ts_1

The killer is transcoding - and my guess is that you're not doing any (or 
at the very minimal just support for a very small number of home/remite 
users) - you are basically a "classic" PBX type scenario - so make sure 
all the phones are using ulaw (if you're in the US, alaw elsewhere) and 
off you go.

I don't know *exactly* what happens to the digital data stream when it's 
bridged between a PRI channel and a SIP channel, but I'd hope if you made 
sure all your SIP phones used the same codec as the PRI then life will be 
simple (and transcoding from ulaw to alaw isn't at all cpu intensive 
anyway, so even if it's wrong, it's not a big issue I reckon)

I'd pick a motherboard based more on what you're familiar with than pure 
spec. So as I have a lot of experience with Asus motherboards, I choose 
them, in particular, I have a few servers based on a "barebones" mini 
tower server from Asus, the TS100 and with a dual-core processor running 
"LAMP" type applications extremely well, so I'm looking to to roll out a 
few for some Asterisk projects soon. (The key with them is remote bios 
access via a serial line, which for remotely hosted boxes is a good 
feature to have IMO!)

So basically any modern server type box will be fine, so go with what 
you're familiar with.

I'd also suggest sticking to 32-bit Debian too - no real reason other than 
(again) familiarity - I have a lot of servers running 32-bit Debian and 
they "just work". I'm not convinced there's much advantage right now in 
moving to 64-bit stuff (unless you're heavilly into scientific stuff and 
lots & lots of memory, and I worked in a place recently where they needed 
just that - 64-bit Suse, 64GB of RAM, 8 CPUs... but it was a bit 
specialist!!!)

But if you've got a lot of experience with 64-bit debian, then go for 
it...

I'd strongly suggest getting the Asterisk sources and compiling them than 
using the supplied packages which are a bit out of date by now, and I'd 
also suggest compiling up a custom kernel too and removing all the hotplug 
nonsense - no modules in the kernel other than the zap, etc. ones. It can 
make booting quicker and you only have loaded exactly what gets used, but 
again, this is personal preferance - I've been doing it since the year 
dot, so I keep on doing it.

Gordon


  >
> Rory
>
> On 04/08/07, Rory Campbell-Lange (rory at campbell-lange.net) wrote:
>> I would be grateful for some comments on our proposed machine specs for
>> a new Asterisk installation at a client with an initial 70 extensions.
>> The system should be able to handle 100 extensions. The system will have
>> the following main features:
>>
>>     - PSTN connection via ISDN 30, dealing with all incoming calls.
>>       Outgoing will be through ISDN initially
>>     - 70-100 Snom 300 handsets
>>     - 1-2 Snom 370 reception phones
>>     - voicemail & voicemail to email
>>     - occasional conferencing requirements
>>
>> This is a normal office environment (architects) and we do not
>> anticipate exceptionally heavy call volumes; on the other hand some
>> conversations will last a very long time.
>>
>> I've had a look at http://voip-info.org/wiki/view/Asterisk+dimensioning
>>
>> We are presently intending to put in 2 number
>>
>>     CHASSIS/CASE: 2U 2HotSwap Bay 510W PSU
>>     MOTHERBOARD: Tyan s5197G2NR
>>     CPU(s): Core2Due E6600 (2*2.4GHz)
>>     MEMORY: 4GB 667 ECC (2*2048)
>>     HDD: 2*150GB Raptor HDD
>>     CD/DVD: DVD/RW
>>     OTHER: Sangoma A101PCI Card
>>
>>     We will be running on 64 bit Debian.
>>
>> The second machine is to be used in place of the first in case of
>> failure.
>
> -- 
> Rory Campbell-Lange
> Campbell-Lange Workshop Ltd.
> <rory at campbell-lange.net>
> <www.campbell-lange.net>
>
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