[asterisk-bugs] [Asterisk 0015770]: [patch] faxing with T.38 fails

[Asterisk Bug Tracker]

A NOTE has been added to this issue. 
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https://issues.asterisk.org/view.php?id=15770 
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Reported By:                Had
Assigned To:                kpfleming
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Project:                    Asterisk
Issue ID:                   15770
Category:                   Channels/chan_sip/T.38
Reproducibility:            always
Severity:                   major
Priority:                   normal
Status:                     feedback
Asterisk Version:           1.4.26.1 
Regression:                 No 
SVN Branch (only for SVN checkouts, not tarball releases): N/A 
SVN Revision (number only!):  
Request Review:              
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Date Submitted:             2009-08-24 12:10 CDT
Last Modified:              2009-08-25 19:51 CDT
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Summary:                    [patch] faxing with T.38 fails
Description: 
I have asterisk 1.4.26.1 setup with T.38 passthrough. I have linksys 2102
ATA and my provider use Cisco gateway with T.38 support enabled. Everytime
I send fax this fail with no apparent reason. 
In sip debug logs it looks that T.38 negotiation was successfull, later I
receive SIP BYE packet from provider and the call si hangup but no fax is
sent.
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 (0109659) Had (reporter) - 2009-08-25 19:51
 https://issues.asterisk.org/view.php?id=15770#c109659 
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OK, I've done couple of tests. 

Before I applied the patch I reverse to the last WM snapshot (which I've
done after I installed and setup asterisk 1.4.26.1). For no particular
reason I tried to send fax before applying of the second patch and I was
very surprised when the fax was sent OK. I've send another 8-10 faxes and
about 50% were successfull. Than I applied the patch and all faxes failed.


But what I found out was:
After the called fax answers and I can hear the modem noise:
- fax is sent OK when the noise is longer and it sounds that it finished
without being broken(before patch)
- fax failed with Comms Error when the noise is cut in the middle and
after short while of quiet period the noise continue and finish (before
patch)
- fax failed without any error message when the noise is cut in the middle
and doesn't continue (after patch)

I also have done traces:

File "before_patch2_good.pcap" is trace from sucessfull fax 
Files "before_patch2_bad.pcap and txt" are trace and logs from
unsucessfull fax
File "patch2.txt" and "patch2trace.pcap" are traces and logs after
applying patch

I hope this make sense.

Thanks 

Issue History 
Date Modified    Username       Field                    Change               
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2009-08-25 19:51 Had            Note Added: 0109659                          
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