[asterisk-users] PRI: sometimes Asterisk drop calls

Giorgio Incantalupo gincantalupo at fgasoftware.com
Wed Sep 13 02:37:39 MST 2006

Hi Steve,

I agree with you..telco knows better!
If telco sends a ring on channel X  and asterisk has already used it, 
couldn't asterisk "shift" that call on another channel Y or it is 
obliged to answer on channel X?
In other words, if asterisk get a ring on channel 3 and channel 3 is in 
use, Asterisk should use channel 6 to answer the call and so connect 
channel 3 to 6. Isn't it? Or I have not correctly understood how telco 
and Asterisk speak between them?

My PBX configuration is (may change due to upgrades):

Debian Sarge 3.1 r0a
asterisk-install: v6
Zaptel: 1.2.6
Libpri: 1.2.3
BRI: install-misdn-mqueue 0.3.1-rc23

Giorgio Incantalupo

Steve Davies wrote:
> On 9/12/06, Giorgio Incantalupo <gincantalupo at fgasoftware.com> wrote:
>> I'm interested to understand why I many messages like:
>> WARNING[21314] chan_zap.c: Ring requested on channel 0/1 already in use
>> on span 1.  Hanging up owner
>> How can a channel be already in use??? That means the channel is
>> busy...if it is so then it is all right...but maybe that shouldn't be a
>> warning but a notice or something else...should it?
> What this means is that a call has arrived from your Telco on a Zap
> channel. Asterisk THINKS that this channel is already in use - In my
> case, asterisk is wrong. Sadly, asterisk hangs up the new call (so
> no-one can call you anymore!) and does not have an option to clean up
> the call data to show the channel as free. Outbound calls are fine,
> but will never be placed on this "hung" channel.
> IMHO, 99% of the time, if the telco says a channel is free, they know 
> best!!!
> As per my other email, I see this problem on one site. Sadly I have
> not been able to identify where it comes from (although I suspect
> broken SIP clients upsetting Asterisk)
> What versions of zaptel/asterisk do you use? What hardware, and what
> phone devices? Perhaps people with this problem have something in
> common.
> To start the ball rolling:
>  Software: Zaptel 1.0.9, Asterisk 1.0.9, BRIstuff-0.2.0, wanpipe-2.3.2
>  PRI interface: Sangoma A101U (UK E1)
>  Phones on sites with NO problems: snom, elmeg, Aastra, Linksys/Sipura
>  Phones on problem site: Hitachi WIP3000, Zyxel F1000 (?)
> Regards,
> Steve
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