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Hello Jenkins Builder,

I'd like you to reexamine a change. Please visit

https://gerrit.osmocom.org/c/osmo-msc/+/33472

to look at the new patch set (#2).

Change subject: CC: don't start guard timer on mid-call MNCC messages ......................................................................

CC: don't start guard timer on mid-call MNCC messages

The intent of the guard timer is to clear hung or stuck states during call setup or teardown. However, there are some MNCC messages that will be exchanged between OsmoMSC (passing CC messages to and from the MS) and the external MNCC agent during the active call state, not related to setup or teardown: DTMF start and stop, plus call hold and retrieve operations for call waiting. Unpatched OsmoMSC restarts the guard timer on every received MNCC message, even those that pass through to CC without affecting any state, and the result is breakage for users.

Consider the case of an IVR where you have to press some DTMF keys before you can be transferred to a human operator. You press the needed keys, get the human operator, and start talking. Then 3 minutes into your conversion (default guard timer duration) your call unceremoniously disconnects without any warning.

Fix: look at the MNCC message type, and skip the call to start the guard timer for known-benign MNCC messages.

Change-Id: Ibe2dd53f8e9e06d175b64df67d2a2e3e2d4155aa --- M src/libmsc/gsm_04_08_cc.c 1 file changed, 49 insertions(+), 1 deletion(-)

git pull ssh://gerrit.osmocom.org:29418/osmo-msc refs/changes/72/33472/2