Erich Dachleger <edachleger(a)yahoo.com> wrote:
Sorry for a real stupid question,
but could this call waiting code somehow establist a third connection
to an ongoing gsm voice traffic channel ?
The software that talks MNCC to OsmoMSC needs to be written properly
in this regard: specifically, in the case of MT calls delivered to
OsmoMSC, the MNCC agent must not send MNCC_RTP_CONNECT until and
unless it receives MNCC_SETUP_CNF. If the MNCC agent were to send
MNCC_RTP_CONNECT right away, then indeed it would disrupt (intrude
upon) the existing voice TCH - however, if the MS sends a CC CONNECT
message which OsmoMSC turns into MNCC_SETUP_CNF, then the MS indicates
that the user would like to accept the new call, in which case
switching the existing TCH to the new call (which is what
MNCC_RTP_CONNECT will do) is appropriate. OTOH, if the user rejects
the new call, then there will never be an MNCC_SETUP_CNF for that
rejected call, and the MNCC agent must never send MNCC_RTP_CONNECT.
osmo-sip-connector appears to behave correctly in this regard, based
on my reading of the code, and of course my own themwi-system-sw is
correct too.
M~