asterisk users - Sep 2006 - is chanisavail command reliable?

Hi,
I have an Asterisk box on a Debian Sarge distro with a Sangoma a102 PRI 
card and I have a big problem: Asterisk drops a lot of outbound calls.
I do not use groups, I want to use a free channel given from Asterisk.

What I do is:
1) use "chanisavail" command to ask Asterisk for a free channel to use
2) use that channel to dial outbound calls

Asterisk gives me the free channel but when I make a call Asterisk tells 
me the channel is not available (I check variable ${AVAILSTATUS}). I 
checked but that channel is not busy on another call.
How can it be possible? Is there anybody who can help me?

TIA


Giorgio Incantalupo

If you have a PRI, why are you telling asterisk which channel to use?
why don't you set groups in zapata.conf and just use g1 or the like?

On 9/18/06, Giorgio Incantalupo <gincantalupo@fgasoftware.com>
wrote:
> Hi,
> I have an Asterisk box on a Debian Sarge distro with a Sangoma a102 PRI
> card and I have a big problem: Asterisk drops a lot of outbound calls.
> I do not use groups, I want to use a free channel given from Asterisk.
>
> What I do is:
> 1) use "chanisavail" command to ask Asterisk for a free channel
to use
> 2) use that channel to dial outbound calls
>
> Asterisk gives me the free channel but when I make a call Asterisk tells
> me the channel is not available (I check variable ${AVAILSTATUS}). I
> checked but that channel is not busy on another call.
> How can it be possible? Is there anybody who can help me?
>
> TIA
>
>
> Giorgio Incantalupo
>
>
>
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On Mon, 2006-09-18 at 10:53 +0200, Giorgio Incantalupo
wrote:
> Hi,
> I have an Asterisk box on a Debian Sarge distro with a Sangoma a102 PRI 
> card and I have a big problem: Asterisk drops a lot of outbound calls.
> I do not use groups, I want to use a free channel given from Asterisk.
> 
> What I do is:
> 1) use "chanisavail" command to ask Asterisk for a free channel
to use
> 2) use that channel to dial outbound calls
I think this is not a good idea since an inbound call could arrive
between 1) and 2) making the channel no longer available (the app isn't
named ChanIsAvailAndReserveForOutgoingCall). Use ZAP/g1 (or whatever
your group is) - works for me on PRI (both as net and as cpe) -
depending on the behaviour of the other side ZAP/G1 could reduce the
likelihood of the same channel being used by both sides.
-- 
Dr. Michael Neuhauser                              mailto:mike@firmix.at
Firmix Software GmbH                                  sip:mike@firmix.at
Vienna/Austria/Europe                               tel:+43-1-7890849-30
Linux Development and Services                     http://www.firmix.at/

On Monday 18 September 2006 04:53, Giorgio Incantalupo
wrote:
> What I do is:
> 1) use "chanisavail" command to ask Asterisk for a free channel
to use
> 2) use that channel to dial outbound calls
The problem is that a race condition exists; the channel could be available at 
time (1), but something could snag it at time (2).  There (currently) is no 
way to lock a channel after it's been detected as free so that something 
later could use it.

My suggestion isn't to use ChanIsAvail() at all; simply Dial and catch 
${DIALSTATUS}, like so:

exten => foo,1,Dial(Tech/exten,,g)
exten => foo,n,Goto(foo-${DIALSTATUS},1)

exten => foo-CHANUNAVAIL,1,NoOp(Nope, wasn't available, gotta do
something
else...)
exten => foo-BUSY,1,NoOp(busy...)
exten => foo-NOANSWER,1,NoOp(no answer...)

that way there is no race condition.  What would maek this better is if you 
could group a bunch of channels, irrespective of technology, together and 
dial that group... something like this

(assume a groups.conf)
1 => SIP/500, IAX2/user@peer/${EXTEN}, Zap/g1
2 => Zap/1,Zap/3,Zap/5
3 => SIP/${EXTEN}@peer

and then do something like this:

exten => _NXXNXXXXXX,1,Dial(GROUP/1,,g)

which would dial SIP/500, IAX2/user@peer/9165551212 and the first available 
channel in the Zaptel group 1...  (assuming 9165551212 was what matched)...

variable expansion would be crucial in this kind of design.  :-)

-A.
>
> Asterisk gives me the free channel but when I make a call Asterisk tells
> me the channel is not available (I check variable ${AVAILSTATUS}). I
> checked but that channel is not busy on another call.
> How can it be possible? Is there anybody who can help me?
>
> TIA
>
>
> Giorgio Incantalupo
>
>
>
> _______________________________________________
> --Bandwidth and Colocation provided by Easynews.com --
>
> asterisk-users mailing list
> To UNSUBSCRIBE or update options visit:
>    http://lists.digium.com/mailman/listinfo/asterisk-users