users per PRI

Answered Question
Apr 4th, 2007

we are moving our NOC and i need to figure out how many users we should allow per PRI.

we have 400 users so i need to figure out how many PRI's we'll need. I think i remember reading 5 users per one phone line.

I have this problem too.
0 votes
Correct Answer by rob.huffman about 9 years 8 months ago

Hi Jerry,

Just wanted to add a note to Sankar and Paolo's good onfo here. The old telco rule is called the "1 in 10" Trunking rule. 1 Trunk/Channel per 10 users. Given the fact that a NOC would probably have a much higher usage rate than your average business your "1 in 5" thought might be perfect. You can always engage your service provider to do a Traffic Study that will also include busyhour averages in your current setup. It is probably good to be over-trunked rather than under-trunked, especially with an environment like yours :)

Hope this helps!

Rob

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jerry.mcrae Wed, 04/04/2007 - 15:02

im not sure how to monitor the PRI. i run solar winds for the ppp t-1's.

Paolo Bevilacqua Wed, 04/04/2007 - 15:06

Telnet to the router during a peak hour. Do "show isdn status" and note the number of used channels.

Correct Answer
rob.huffman Thu, 04/05/2007 - 06:08

Hi Jerry,

Just wanted to add a note to Sankar and Paolo's good onfo here. The old telco rule is called the "1 in 10" Trunking rule. 1 Trunk/Channel per 10 users. Given the fact that a NOC would probably have a much higher usage rate than your average business your "1 in 5" thought might be perfect. You can always engage your service provider to do a Traffic Study that will also include busyhour averages in your current setup. It is probably good to be over-trunked rather than under-trunked, especially with an environment like yours :)

Hope this helps!

Rob

Tommer Catlin Thu, 04/05/2007 - 08:54

I agree with Rob. I usually do a 1-10 ratio on PRIs. Even that sometimes is a little much, but id rather be over than under if you can. CDR systems will help you alot, the local telco will probably never help you on your traffic patterns, no matter how much you ask, and they use 1-4 ratio (so they can sell more PRIs to you!)

If it's a call center, it's almost a 1-1 ratio with extra for admin personel, etc.

cheers!

jerry.mcrae Thu, 04/05/2007 - 08:59

thanks everyone - i'll get on it.

speaking of these PRI's there down - a fun morning at work.

letmeinnn Thu, 04/05/2007 - 13:54

hey

the real time monitoring tool tells you whats in use...

Very useful tool

Cheers

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