[asterisk-ss7] ANM without ACM

[Bryan Scott]

I've seen this before too.

I have a couple of Asterisk boxes hanging off a switch using SIP.  I also used to explicitly Answer() as the call came in from the switch.  My guess is our switch converts SIP signaling straight to SS7, because anytime a call came in from a specific in-state AT&T tandem, they released the call as soon as I answered it.  

Turns out putting a Ringing() before Answer() solved the problem.  It is likely that certain carriers have equipment that is not tolerant of out-of-order messages.  I say that because calls from all other operators were successful, as were calls from AT&T wireless originating on out-of-state tandems.

-- Bryan

On May 6, 2010, at 5:30 PM, Horacio J. Peña wrote:
> 
> Thanks for the answer!
> 
> Should the asterisk user be aware of each protocol intricacies? Shouldn't
> it be the channel task to send the needed messages? Conversely, should
> the user be able to make asterisk to do things not allowed by the
> protocols?
> 
> Saludos!
> H
> 
> On Thu, May 06, 2010 at 11:18:56PM +0000, gustavomarsico at gmail.com wrote:
>> Is not legal to send an ANM without ACM. You can send a CON instead of ANM.
>> Try to put a Proceeding() in the dial plan.
>> 
>> 
>> Sent via BlackBerry by AT&T
>> 
>> -----Original Message-----
>> From: Horacio J. Peña <horape at compendium.com.ar>
>> Date: Thu, 6 May 2010 20:03:43 
>> To: <asterisk-ss7 at lists.digium.com>
>> Subject: [asterisk-ss7] ANM without ACM
>> 
>> Hola!
>> 
>> I'm playing with libss7 and found that if I make a dialplan like:
>> 
>> exten => 08231451010,1,Answer
>> ...
>> 
>> the result is:
>> 
>> 105  12.024960         2146 -> 639          ISUP(ITU) IAM (CIC 2)
>> 107  12.028962          639 -> 2146         ISUP(ITU) ANM (CIC 2)
>> 109  12.065962         2146 -> 639          ISUP(ITU) RSC (CIC 2)
>> 111  12.068958          639 -> 2146         ISUP(ITU) RLC (CIC 2)
>> 113  12.103963         2146 -> 639          ISUP(ITU) RSC (CIC 54)
>> 
>> It seems that the switch I'm connecting to doesn't accept ANM without a
>> previous ACM. Who is wrong? asterisk (libss7) sending ANM directly or
>> the other switch not allowing that?
>> 
>> Thanks!