[asterisk-users] Zap channels unavailable?

[jan.sarin at securia.se]

Hi,

I was talking to a technican at our telco yesterday and he told me that
this problem was most likely caused by our PBX sending "channel
identification" Exclusive when we dial out. If there's a heavy load and
someone is dialing in on the same time on the same channel that we try
to dial out from - it causes a deadlock. He said some Cisco PBXs have
the same problem.

Now, I'm no asterisk expert and I don't quite understand what this
means. I've emailed the list asking if this can be changed to Preferred
or Negotiation as the technican told me to. But I got no response yet.

I did however "solve" the problem by reversing the channels that we dial
out from (so now it tries the last channel first and then backwards to
the first). Since all of our incoming calls come from the first to the
last this minimizes the risk of a "collision" of the incoming/outgoing
calls. This is of cource no long-term solution but anyway.

I need to know if it's possible to change "channel identification"
(whatever that is) to preferred or negotiation.

Regards,
Jan



Martin Smith wrote:

Hello Jan,

We have also been seeing this issue, and we are running Asterisk
1.2.17/Zaptel 1.2.16/LibPRI 1.2.4-r2. We have been informed by our PRI
provider that a "3rd party vendor" has applied firmware to some hardware
along our path, and that it has an unfortunate bug of hanging B-channels
in the PRI flags "resetting" state. We have been assured that the vendor
has been given a 30-day deadline (starting maybe 2 weeks ago) to fix the
problem, and that it will go away soon. In the mean time, we've also had
to restart Asterisk to free our B-channels for use, and any link-level
event potentially re-hangs them.

Keep us posted if you find out anything!

Martin Smith, Systems Developer
martins at bebr.ufl.edu
Bureau of Economic and Business Research
University of Florida
(352) 392-0171 Ext. 221 

 

> -----Original Message-----
> From: asterisk-users-bounces at lists.digium.com 
> [mailto:asterisk-users-bounces at lists.digium.com] On Behalf Of 
> jan.sarin at securia.se
> Sent: Tuesday, July 17, 2007 9:44 AM
> To: asterisk-users at lists.digium.com
> Subject: [asterisk-users] Zap channels unavailable?
> 
> Hi,
> 
> Lately we've noticed that some Zap channels on one of our PRIs are
> unavailable. We have 2 PRI lines with 60 channels in total. 
> On the first
> PRI there are currently 20 channels that are not being used for some
> reason.
> 
> I tried googling around and found some similar problems but 
> there really
> was no solution (?). I'm not sure if this problem has occured now
> because of more load on the pbx but the machine should take 
> it just fine
> (2x3,0 ghz xeon with 1 gb ram etc).
> 
> Restarting asterisk makes the zaps' available again but they get
> "locked" later again. It seems it's always the same channels that are
> unavailable too?
> 
> This one is unavailable and not being used... It's been in PRI Flags
> state "resetting" for hours now. 
> 
> Channel: 1
> File Descriptor: 11
> Span: 1
> Extension:
> Dialing: no
> Context: from-pstn
> Caller ID: 702821667
> Calling TON: 33
> Caller ID name:
> Destroy: 0
> InAlarm: 0
> Signalling Type: PRI Signalling
> Radio: 0
> Owner: <None>
> Real: <None>
> Callwait: <None>
> Threeway: <None>
> Confno: -1
> Propagated Conference: -1
> Real in conference: 0
> DSP: no
> Relax DTMF: no
> Dialing/CallwaitCAS: 0/0
> Default law: alaw
> Fax Handled: no
> Pulse phone: no
> Echo Cancellation: 128 taps unless TDM bridged, currently OFF
> PRI Flags: Resetting
> PRI Logical Span: Implicit
> Hookstate (FXS only): Onhook
> 
> If anyone can help me with this I'd be really glad. Thanks.
> 
> Regards,
> Jan
> 
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