[asterisk-bugs] [Asterisk 0017071]: When using another SIP Trunk, Asterisk generates the initial ring RING as a response to "SIP SESSION PROGRESS"

[Asterisk Bug Tracker]

A NOTE has been added to this issue. 
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https://issues.asterisk.org/view.php?id=17071 
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Reported By:                Alex Oniciuc
Assigned To:                
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Project:                    Asterisk
Issue ID:                   17071
Category:                   Channels/chan_sip/General
Reproducibility:            always
Severity:                   minor
Priority:                   normal
Status:                     new
Asterisk Version:           Older 1.6.0 - please test a newer version 
JIRA:                        
Regression:                 No 
Reviewboard Link:            
SVN Branch (only for SVN checkouts, not tarball releases): N/A 
SVN Revision (number only!):  
Request Review:              
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Date Submitted:             2010-03-22 05:43 CDT
Last Modified:              2010-03-22 11:29 CDT
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Summary:                    When using another SIP Trunk, Asterisk generates the
initial ring RING as a response to "SIP SESSION PROGRESS"
Description: 
I’m having a strange problem with the VoIP Gateway that I’m using to go
on the PSTN: if the number on the other end is busy or unavailable I hear
an initial RING, generated by Asterisk from what I’m seeing and after
that the line goes down with busy signal:

Here is the scenario:

    Softphone    *ASTERISK                PATTON                   PSTN
[BUSY]

1   INVITE     >  INVITE              >   INVITE
2.	                              <   SIP/2.0 100 Trying
3.  RING      <  SIP/2.0 180 Ringing  <   SIP/2.0 183 Session Progress
4.	      <  SIP/2.0 603 Declined <   SIP/2.0 406 Not Acceptable

Is this regular? Asterisk isn’t supposed to generate the RING  only
after the first one received from the PATTON?

This can be very annoying because the calling party may have the
impression that the remote party hang up.
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 (0119658) Alex Oniciuc (reporter) - 2010-03-22 11:29
 https://issues.asterisk.org/view.php?id=17071#c119658 
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I've attached the log from Asterisk 1.6.1.6 and a PATTON SN 4961. This
version of Asterisk has the same issue: generates the RING after SESSION
PROGRESS.

To test this I've removed the battery from my cell phone, this way my
mobile operator returns the voicemail after 15 secs of silence. If I call
with a mobile phone or another PBX (Cisco) I'm getting 15 seconds of
silence and the voicemail after.
Passing thru Asterisk I'm getting 3 "RING"'s (during these 15 seconds) and
the voicemail. 

Issue History 
Date Modified    Username       Field                    Change               
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2010-03-22 11:29 Alex Oniciuc   Note Added: 0119658                          
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