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Bug #1817

closed

in-call dtmf broken for iphone

Added by msuraev over 7 years ago. Updated over 7 years ago.

Status:
Closed
Priority:
Normal
Assignee:
Category:
-
Target version:
-
Start date:
10/11/2016
Due date:
% Done:

100%

Spec Reference:

Description

If iphone (tested with modem firmware v 6.01.00) in call (both received and dialed) will send dtmf (press some keys on dial pad while still in call) than it's impossible to terminate this call from iphone. With acer phone (MTK-based baseband) there is no such effect.

Could be some bug in iphone or could be bug on our side which is ignored by MTK. Or both. Further investigation is required.


Files

Iphone-_DTMF-_BlackBerry.pcapng Iphone-_DTMF-_BlackBerry.pcapng 190 KB wirelesss, 10/28/2016 02:47 PM
BlackBerry-_DTMF-_Iphone .pcapng BlackBerry-_DTMF-_Iphone .pcapng 130 KB wirelesss, 10/28/2016 02:47 PM
Iphone-_DTMF-_BlackBerry.pcapng Iphone-_DTMF-_BlackBerry.pcapng 190 KB wirelesss, 10/28/2016 02:47 PM
SonyEricsson-_DTMF-_Iphone.pcapng SonyEricsson-_DTMF-_Iphone.pcapng 81.4 KB wirelesss, 10/28/2016 02:47 PM
0001-mncc_builtin-Properly-reject-DTMF.patch 0001-mncc_builtin-Properly-reject-DTMF.patch 1.51 KB proposed fix for 'dtmf with built-in mncc' laforge, 10/29/2016 08:27 PM
Actions #1

Updated by laforge over 7 years ago

  • Assignee set to wirelesss

wirelesss: Please take A-bis pcap traces of 'DTMF' use of various phones and try to reproduce this behavior. Once we have the traces attached to this ticket we can start to compare them for any differences.

Actions #2

Updated by wirelesss over 7 years ago

Described behavior has been reproduced. It occurs in a situation where iphone is as an A-subscriber and Sony Ericsson G705u or Black Berry Curve 8520 are selected as a B-subscriber. Sending DTMF from iphone side to Black Berry or Sony Ericsson followed by pressing of Hangup button do not release ongoing voice call.

The same test has been done by using Sony Ericsson G705u (SE) / Black Berry Curve (BB) as a A-subscriber. Sending DTMF from SE or BB to Iphone followed by pressing of (Sony Ericsson's or Black Berry's) Hangup button released the call just as it should.

Following four traces are attached.

- Iphone->DTMF->BlackBerry.pcapng (call can not be released by pressing Iphone's Hangup button)
- BlackBerry->DTMF->Iphone .pcapng
- Iphone->DTMF->BlackBerry.pcapng (call can not be released by pressing Iphone's Hangup button)
- SonyEricsson->DTMF->Iphone.pcapng

Actions #3

Updated by laforge over 7 years ago

please have a first look at the protocol traces and see if you can see anything different between the working / non-working case. My guess would have been that we don't properly ack the DTMF message and until that happens, there is a reference count against the radio channel, and thus it is not released - or something like that.

Actions #4

Updated by laforge over 7 years ago

  • Project changed from OsmoBTS to OsmoNITB

I had a quick look at this as I had some time on my flight: As can be seen in the trace, there is a START DTMF from iPhone to network, but we never send a START DTMF ACK back to the phone. See 3GPP TS 23.014 on how the signalling of DTMF should be in GSM networks.

It seems that we convert the START DTMF / STOP DTMF messages into the MNCC primitives MNCC_START_DTMF_IND and MNCC_STOP_DTMF_IND. In case of an external MNCC handler, those are exposed 1:1 and expected to be handled. I suppose lcr implements them. osmo-sip-connector ignores them so far.

In the internal mncc handler, OsmoNITB seems to lack support for DTMF. Normally I would expect that the messages should b e forwarded, so that DTMF tones are played back at the 'B' subscriber. However, only MO-DTMF is implemented in GSM, there is no MT-DTMF :(

Actions #5

Updated by laforge over 7 years ago

  • File mncc.diff added
  • Status changed from New to In Progress

Plase try building openbsc with attached patch and see if that fixes the problem.

Actions #6

Updated by laforge over 7 years ago

  • File deleted (mncc.diff)
Actions #7

Updated by laforge over 7 years ago

attaching proper git format-patch output.

Actions #8

Updated by wirelesss over 7 years ago

  • % Done changed from 10 to 70

The patch fixed reported issue.

Actions #9

Updated by laforge over 7 years ago

  • Status changed from In Progress to Resolved
  • % Done changed from 70 to 100

I have submitted the patch to gerrit + merged it, see https://gerrit.osmocom.org/#/c/1181/

Actions #10

Updated by laforge over 7 years ago

  • Status changed from Resolved to Closed
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