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Guest · Posted: Wed Sep 28, 2005 2:32 am Post subject: Fast Busy

We have a Nortel Nortsar MICS using a PRI with 23 channels.
Occasionaly (once a week) when someone tries to dial out to a local or
long distance number they get a fast busy signal. Like wise when I
have tried to dial in to either a DID number or the general company
number I received a fast busy.

I have had the telco company check the line as well as the company that
supports our phone system and no one has any idea.

What could be causing this?

Thanks

Ryan

Michael Andrews · Guest

Does this happen at very busy times? It seems possible (from the
amount of information I have gleaned) that all the lines coming into
the Norstar are full. Although now that I think of it, I'm not sure
that would return a fast busy signal (I can't remember exactly what
happened the last time we had full PRI blockage at this site).

Guest · Posted: Wed Sep 28, 2005 9:37 pm Post subject: Re: Fast Busy

Actually we have 12 employees and 23 lines so nealy impossible unless
everyone was on the phone and receiving a call. I beleive we have 22
or 23 inbound line with the PRI, correct?

Thanks for your response.

Ryan

Michael Andrews · Guest

Yes, a PRI has 23 "B" (bearer) channels and 1 "D" (data) channel. It's
possible, however improbable, that all the lines could be used. If you
have 10 people making outbound calls, and 13 people trying to call in,
leaving/checking voicemail, connecting to modems, sending faxes, etc,
you could have some blockage there.

I would call telco and ask them for a traffic report on the circuit for
a specific day that you know you experienced the issue. While this is
likely not the cause with such a small (and probably over-trunked)
office it may point you in the right direction.

I'll be interested to know what you find out!

~ Michael

Guest · Posted: Fri Sep 30, 2005 4:19 am Post subject: Re: Fast Busy

Michael,

Thanks for your comments and concern. Our Nortel phone support company
came out for a few hours this morning. Last night before I left I
turned on the PC based syslog for our Adtran Atlas 550 that sits
between the Nortel and the Telco. This morning when I came in not much
info was revealed except for this attempt that was captured:

Sep 29 08:29:24 10.0.0.126 ATLAS 550[ADTRAN]:ISDN|Ntw2|1|Call to
ATLAS:'719xxxx' received.
Sep 29 08:29:24 10.0.0.126 ATLAS 550[ADTRAN]:ISDN|Ntw1|1|Dialing
719xxxx
Sep 29 08:29:24 10.0.0.126 ATLAS 550[ADTRAN]:ISDN|Ntw1|1|Gate opened
to name by Proceeding Msg.
Sep 29 08:29:25 10.0.0.126 ATLAS 550[ADTRAN]:ISDN|Ntw1|1|Call
clearing: UNASSIGNED_NUMBER : Loc=U
Sep 29 08:29:25 10.0.0.126 ATLAS 550[ADTRAN]:ISDN|Ntw1|1|Call to
'719xxxx' failed
Sep 29 08:29:25 10.0.0.126 ATLAS 550[ADTRAN]:ISDN|Ntw2|1|Call to
'719xxxx' busy after switchboard has connected it.
Sep 29 08:29:25 10.0.0.126 ATLAS 550[ADTRAN]:ISDN|Ntw2|1|Busy
destination: UNSPECIFIED_CAUSE : Loc=LN
Sep 29 08:29:26 10.0.0.126 ATLAS 550[ADTRAN]:ISDN|Ntw2|1|Call to
'719xxxx' disconnected by far end.

Adtran tech support is sending a new chassis. No idea, but tomorrow
the Nortel company is coming back to take the Adtran out of the loop
(we will lose out fax machine for a few days) to see if we can isolate
while we wait for the replacement chassis.

Will let you know what happens.

Ryan

Michael Andrews · Guest

Very interesting, thanks for the follow-up.

Michael Andrews · Guest

Because I was interested (and someone else reading this might be)
here's the link to Adtran's product information page on the Atlas 550:

http://www.adtran.com/adtranpx/Rooms/DisplayPages/LayoutInitial_webrQS
_UHJvZHVjdENhdGVnb3J5PWNvbS53ZWJyaWRnZS5lbnRpdHkuRW50aXR5JTVCT0lEJTVCNDI5OTMzNkQwMTFFQzA0MkEwNUYxRDBDN0IzRTJBRDkl/NUQlNUQmUHJvZHVjdD1jb20ud2VicmlkZ2UuZW50aXR5LkVudGl0eSU1Qk9JRCU1QkI0NkJGRUJBQTc1OEY0NDI5NDZGOUI5RjE2MDlFMUMyJTVEJTVEJkNvbnRhaW5lcj1jb20ud2VicmlkZ2UuZW50aXR5LkVudGl0eSU1Qk9JRCU1QkFGOTVGNzRBRTJCMzExNDU4QUVEMUVFN0RCNTBDMTQzJTVEJTVE/

What a strange little device! Looks like a mini-PBX or something to
that effect (although it's listed as a router... well I guess that's
what a PBX is though, right? :). I can't really make heads or tails of
it myself. :D

Guest · Posted: Wed Oct 05, 2005 4:21 pm Post subject: Re: Fast Busy

The Atlas 550 is amazing. I know it does many other things, but I use
it to allow the break out the PRI into analog circuits. I have 16
analog ports on the 550 that I connect to analog modems to dial out at
night when there is zero phone system traffic. It dynamically uses and
release the 23 lines from the PRI that feed the Nortel phone system.
It will also band together 2-4 T1s into a single channel for increased
throughput (I believe). Pretty cool tool and there Tech support is
better than Cisco!

Anyways, seems the problem is the 550 as we removed it while we waited
for a replacement from Atlas and the problem has disappeared.

Thanks for the help.

Ryan

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