[asterisk-bugs] [LibPRI 0016859]: answer() accepted without receiving CONNECT ACKNOWLEDGE from the ISDN network

[Asterisk Bug Tracker]

The following issue has been UPDATED. 
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https://issues.asterisk.org/view.php?id=16859 
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Reported By:                lsimoes
Assigned To:                rmudgett
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Project:                    LibPRI
Issue ID:                   16859
Category:                   General
Reproducibility:            always
Severity:                   major
Priority:                   normal
Status:                     closed
Asterisk Version:           SVN 
JIRA:                       SWP-1684 
libpri Version:             1.4.10.2 
SVN Branch (only for SVN checkouts, not tarball releases): N/A 
SVN Revision (number only!):  
Disclaimer on File?:        N/A 
Request Review:              
Resolution:                 not fixable
Fixed in Version:           
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Date Submitted:             2010-02-18 00:34 CST
Last Modified:              2010-07-22 19:12 CDT
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Summary:                    answer() accepted without receiving CONNECT
ACKNOWLEDGE from the ISDN network
Description: 
Hello,

Our system is composed by:
   linux - 2.6.26
   Asterisk - 1.6.2.0-rc2
   dahdi-linux - 2.2.0.2
   libpri - 1.4.10.2
   HW Digium TE420

We verified that some calls are considered correctly accepted and
registered in the CDR as ANSWERED, even when there is not a CONNECT
ACKNOWLEDGE received from the E1 line, as you can see from the signalling
traces. Included are 3 traces.

We have found several of these situations.

This appears to be related to periods of intense calls receiving.

Also it appears that there are no response to STATUS messages from the
network.

Thanks in advance for any help to solve this issue.

Regards,
Leonel

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 (0124886) rmudgett (administrator) - 2010-07-22 19:12
 https://issues.asterisk.org/view.php?id=16859#c124886 
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The main item you have here is that the CDR is recording a call as
ANSWERED when the ISDN network has not sent a CONNECT ACKNOWLEDGE message
in response to the CONNECT message sent by Asterisk.  This is expected
behavior.  Asterisk has answered the call.

The other question you had was about the STATUS message.  The STATUS
message does not expect a reply.  It is the current status of the sender.
The only time a STATUS message requires a response by the receiver is
when
the STATUS message indicates that the call state is NULL.  If the sender
indicates his call state is NULL then the receiver is supposed to
immediately discard the indicated call because the sender does not think
a
call exists.

The STATUS message in trace two is because the network sent the
DISCONNECT
message before it processed the CONNECT message from Asterisk.  This kind
of situation can come about because of heavy load on the network side
delaying the processing of signaling messages. 

Issue History 
Date Modified    Username       Field                    Change               
====================================================================== 
2010-07-22 19:12 rmudgett       Note Added: 0124886                          
2010-07-22 19:12 rmudgett       Status                   assigned => closed  
2010-07-22 19:12 rmudgett       Resolution               open => not fixable 
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