[asterisk-bugs] [LibPRI 0013485]: [patch] Force SIP Ringing when connecting trough a telco that uses NEC Neax InterUrban CO

[Asterisk Bug Tracker]

The following issue has been UPDATED. 
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http://bugs.digium.com/view.php?id=13485 
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Reported By:                alerios
Assigned To:                mattf
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Project:                    LibPRI
Issue ID:                   13485
Category:                   General
Reproducibility:            always
Severity:                   minor
Priority:                   normal
Status:                     closed
Asterisk Version:           Older 1.4 
SVN Branch (only for SVN checkouts, not tarball releases): N/A 
SVN Revision (number only!):  
Disclaimer on File?:        N/A 
Request Review:              
Resolution:                 fixed
Fixed in Version:           
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Date Submitted:             2008-09-15 11:23 CDT
Last Modified:              2008-09-16 11:39 CDT
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Summary:                    [patch] Force SIP Ringing when connecting trough a
telco that uses NEC Neax InterUrban CO
Description: 
This is related to issue http://bugs.digium.com/view.php?id=12153

After several months of tracking and debugging this issue with the Telco
side, we found out that the problem shows up when the broadband PSTN
carrier uses an interurban CO NEC Neax which doesn't handle the ISDN-to-SS7
translation in a proper manner:

- When we send "100 Trying" and then "200 OK", the NEC CO sends a SS7 ACM
message to the other end and triggers a timer waiting for an ANM message,
hence making the call drop after 90 sec.

- When we send "100 Trying", followed by an "180 Ringing", and then "200
OK", the call doesn't get dropped, and everything works fine.

(Also see recommendation Q.2650)


I'm attaching the patch where I forced the sending of "180 Ringing" always
after "100 Trying". Its an awful hard-coded patch, but I hope someone could
adapt it to make it an option in sip.conf in the future.
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Issue History 
Date Modified    Username       Field                    Change               
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2008-09-16 11:39 mattf          Status                   assigned => closed  
2008-09-16 11:39 mattf          Resolution               open => fixed       
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