[asterisk-bugs] [Asterisk 0014793]: Asterisk shouldn't send dialog NOTIFY <state>early</state> until it receives a 1XX-non100 response from the callee

[Asterisk Bug Tracker]

The following issue has been UPDATED. 
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https://issues.asterisk.org/view.php?id=14793 
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Reported By:                ibc
Assigned To:                
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Project:                    Asterisk
Issue ID:                   14793
Category:                   Channels/chan_sip/Subscriptions
Reproducibility:            always
Severity:                   minor
Priority:                   normal
Status:                     acknowledged
Asterisk Version:           SVN 
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:             2009-03-31 10:52 CDT
Last Modified:              2010-12-20 10:40 CST
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Summary:                    Asterisk shouldn't send dialog NOTIFY
<state>early</state> until it receives a 1XX-non100 response from the callee
Description: 
Escenario:

1) "CALLER" and "CALLEE" are users of the PROXY and exist as friend's in
sip.conf with "host=PROXY".
2) Phone "SUBSCRIBER" is subscribed to dialog status of phone "CALLEE" in
ASTERISK.
3) "CALLER" calls to "CALLEE" throught the PROXY.
4) PROXY routes the INVITE to ASTERISK.
5) Asterisk generates a NOTIFY for SUBSCRIBER with <state>early</state> 
<--- WRONG !
6) The PROXY receives the INVITE and returns 480 since CALLEE is not
registered.
7) Asterisk then sends a NOTIFY <state>terminated</state> to SUBSCRIBER.


Step 5 is wrong. According to RFC 4235, Asterisk *shouldn't* generate a
NOTIFY <state>early</state> until it receives a provisional (non 100)
response from the callee (so containing To_tag).
In the above case, this means that Asterisk shouldn't send a NOTIFY to the
subscriber since the callee didn't ring (it wasn't registered in the proxy
in fact).

I've tested and the behaviour of Asterisk is the *same* when using local
SIP users instead of remote SIP users.

Conclusion: Asterisk should send a dialog NOTIFY <state>early</state> just
in the case it receives a 1XX non100 response from the callee:
- If the user is local and is not registered, Asterisk shouldn't generate
a NOTIFY.
- If the user is local and *is* registered, but doesn't reply to the
Asterisk INVITE (phone crash?), Asterisk shouldn't generate a NOTIFY. 
- If the callee is remote, Asterisk shouldn't generate a NOTIFY if it
doesn't receive a provisional 1XX non100 response from the callee.

I attach a SIP trace showing the above scenario and SIP flow.
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Issue History 
Date Modified    Username       Field                    Change               
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2010-12-20 10:40 lmadsen        Description Updated                          
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