SipDroid not accepting/processing CANCEL

[GoogleCodeExporter]

What steps will reproduce the problem?
1. register the phone against NetSapiens NMS
2. configure a pre existing extension for Synchronous Calling (Follow Me)
3. call the parent linked extension from another phone
4. don't answer the call, hangup the calling phone

What is the expected output? What do you see instead?

I would expect the phone to stop ringing, instead it continues. When I look at 
the trace, I see that the NMS switch is sending a CANCEL to the phone, but it's 
ignoring it, causing retransmissions, and after several, sipdroid responds with 
a 403 Forbidden.

You should be able to see the trace here:

https://boss.netsapiens.com/nsflow/trace/call_trace_admin_versature_com_13517909
77/index_with_frames.html

What version of the product are you using? On what device/operating system?

Version 2.7 Beta, on a Samsung/Google Nexus 7 running Android 4.1.2 (Jelly Bean)

Which SIP server are you using? What happens with PBXes?

NetSapiens SiPBx 1-1215c. Haven't tried with PBXes, but I suspect this problem 
will not occur.

Which type of network are you using?

Tried this and seen the same behaviour over WIND 3G, and via wifi.

Please provide any additional information below.

I suspect this is an issue in the signalling from NetSapiens, since I have used 
this phone in a similar configuration against Asterisk 1.8.x with no issues.

Either NetSapiens or SipDroid is not adhering the RFC properly, and I'd like to 
be able to identify which one, so this can be escalated to NetSapiens if 
necessary.

Original issue reported on code.google.com by squig...@versature.com on 1 Nov 2012 at 5:52

[GoogleCodeExporter]

Just as a followup, I configured and connected a Grandstream ATA to the system 
as well, and configured it to simultaneous ring. I can call from an alternate 
phone, and then cancel, and the polycom and grandstream stop ringing, and 
sipdroid continues.

Original comment by squig...@versature.com on 6 Nov 2012 at 5:21

[GoogleCodeExporter]

Also, I see now that I appear to have created a duplicate issue, since this 
looks similar to 517, 513, 217, 420, but they are all "Fixed" or "Invalid", yet 
I'm still having the issue.

Here's another sip trace:

https://boss.netsapiens.com/nsflow/trace/call_trace_admin_versature_com_13522245
84/index_with_frames.html

Where you can see the CANCEL being sent to all 3 devices, and 2 are responding 
OK and 487, but sipdroid is not responding to the CANCEL.

Original comment by squig...@versature.com on 6 Nov 2012 at 5:58