[asterisk-users] PSTN to SIP line ratio

[Steve Edwards]

>> On Thu, 15 Oct 2009, Shahnawaz Mir wrote:
>>
>>> I am planning to deploy an Asterisk PBX for 100-200 users. I am not 
>>> sure about PSTN incoming/outgoing line ratio for SIP users. I mean if 
>>> you recall dial up internet the common line ratio is 1:10 (one line 
>>> for 10 users on access server or an E1 for 300 users). Can somebody 
>>> tell me what is the good ratio for incoming and outgoing analogue/ 
>>> digital PSTN lines.

> ----- "Steve Edwards" <asterisk.org at sedwards.com> wrote:
>>
>> 42[:1]
>>
>> (The fact that you ask such a generic question implies you have a high 
>> probability of failure. You should hire somebody with a bit more clue 
>> and learn from them.)

On Thu, 15 Oct 2009, Tim Nelson wrote:

> Ignoring unhelpful snobbish remarks from the peanut gallery...

Really? Seriously?

Maybe facetious and direct, but not intended to be snobbish or unhelpful.

> Your ratio will depend largely on the usage by your users. In a busy 
> contact center where your users/agents will be on calls nearly 100% of 
> the time, your ratio will need to be closer to 1:1. However, if the 
> installation is for a school where most of the staff (teachers) are 
> instructing in the classroom or otherwise away from their desks, you can 
> get by with a higher ratio like 4:1.

Assuming the OP meant "how many PSTN lines (incoming and outgoing) for 
every x SIP users" (and that you meant 1:4), without knowing the 
application, 42:1 (or 1:42) is just as relevant as 1:1 or 1:4.

(As a parent, if 25% of the teachers are yakking to somebody off-campus, 
I'd raise holy hell.)

> As always, you build your system with room for expansion in the event 
> you need additional resource availability. Also, ensure your 
> customer/client understands the limitations of the number simultaneous 
> calls. If you don't tell them and they find out the hard way, you'll be 
> in a world of hurt.

Without the guidance of someone who has been down the road before, he is 
likely to hit every pothole.

I still think hiring some talent to either "do the job" or "mentor" the OP 
is the most helpful advice I could give.

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