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Solution for missed call indication on multiple registration

Posted: Wed Nov 26, 2014 8:35 am
by ozimarco
Hi Aaron,

When we have the same SS account registered on a number of devices and an incoming call is answered on one device, every other device will show this as a 'missed call', even though it was answered, just not on those particular units. Someone on Whirlpool (http://whrl.pl/Rd9mwj) suggested this:
They should be sending a cancel message with a "call completed elsewhere" reason code and the call should not be logged as a missed call at any handset.
I never realised that this solution was technically possible and am still not convinced that it is. What is your opinion? I mean, it would be awesome if this could be implemented but I am not getting my hopes up.

Thanks,
Mark

Re: Solution for missed call indication on multiple registra

Posted: Wed Nov 26, 2014 9:24 am
by Aaron
To the best of my knowledge it's almost certainly not possible. When one of the forked calls is answered the CANCEL request is sent to any other forked call still in progress which is what causes them to stop ringing. The missed call indication comes from the device itself. The SIP standard does not distinguish between a CANCEL request that was generated because the calling party gave up (in this case that would be a genuine missed call) and a CANCEL request that was generated because the call was answered elsewhere.

It would be possible to add an extra header to the CANCEL request to distinguish between the two cases but no device will support it because it's not part of the standard.

I have the same problem. Calls that get answered on my Siemens handset leave a missed call indication on my Cisco IP Phone.

Re: Solution for missed call indication on multiple registra

Posted: Wed Nov 26, 2014 12:48 pm
by ozimarco
Thanks, Aaron. That clears it up for me.