[asterisk-users] pstn failback

Shawn Kelley shawn at sellersaide.com
Fri Sep 29 08:39:44 MST 2006

I agree with the comment below, we switched from analog lines to a PRI and
it's not always as reliable as some people think. We are in a somewhat rural
location and we have outages regularly. 1-4 hour outages every few months
are not uncommon for us. Outages of 60 seconds or so are even more common.
I'm told this is because the T1 line is running somewhat noisy/dirty and
after so many CRC errors the equipment is resetting.

Make sure you negotiate a good SLA so that you can get credit when it does
go down!

You also have to be careful like mentioned below, if you get 2 PRI's, even
from different CLECS, the will normally still come out of the same Central
Office and travel side by side on the cable. So it's likely if 1 goes down
then the other one will also. 

Summary:  It's a good idea to have a few analog lines since they can take a
whole lot more abuse than the digital T1 can handle. (Static/Noise doesn't
make your call drop!)

-----Original Message-----
From: Lacy Moore [mailto:lists-away at aspendoratechnologies.com] 
Sent: Friday, September 29, 2006 4:23 AM
To: Asterisk Users Mailing List - Non-Commercial Discussion
Subject: Re: [asterisk-users] pstn failback

Hash: SHA1

stan ford wrote:
> On fonalities web page, i see they offer pstn failback as a feature of
their asterisk package. i've also heard before of failing back to a pri line
if your t1 voip line fails. my question is. in order to have pstn or pri
failback, dont you basically have to have all the equipment there on
standby, a PRI line, TDM cards, PRI/T1 cards, a bunch of digital or analong
phones. it just seems like a whole lot of hardware to be sitting there
waiting for a disaster. unless im just not understanding pstn/pri failback.
can someone shed some light?
>   also, if you've got a dedicated full t1 line for voice, and have a low
amount of users for that t1, is there really to worry about failing back to
a pstn? seeing how reliable a t1 is. is anyone out here using full voip
telelphony solution only?
Having had our XO connection go down within a week or so of switching to
a PRI, I can see how having a fallback would be good.  It was down for
about 4 hours.  However, that was back in May or June and hasn't been
down since.  I couldn't justify having something on standby for our
business.  But, our clients can reach us by phone in the office or cell,
and we can easily make outgoing calls on our cellphones. Our type of
business is not really dependent on absolutely having the phones up 100%
of the time.

If you do get a fallback, get it from different providers.  If your T1
from provider X is down, chances are a PRI from provider X will be
following the same path and be down as well.
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