7 Dec
2022
7 Dec
'22
9:18 p.m.
Vadim Yanitskiy <vyanitskiy(a)sysmocom.de> wrote:
[changing order slightly]
Just to clarify: currently when you invoke the
silent-call command, no
Call Control signalling is happening at all. Only paging and then the
RR Assignment procedure. Strictly speaking it's not really a "call",
just a channel assignment without any further commands.
I know, I read the code.
As I already mentioned, the existing silent-call
command is a bit
special in a way that it allows to select a specific TCH rate (full or
half) and a specific codec (if needed). The test-call command I
proposed can by implemented on top of the existing silent-call logic.
And how exactly do you propose implementing an actual MT call (with MT
SETUP CC message to MS) on top of this silent-call logic? The moment
you send that MT SETUP message to an MS, that MS will respond with CALL
CONFIRM and other CC messages to follow - how are you going to handle
them? You will need at least some handling of CC messages from MS: if
the MS sends DTMF start, call hold or call modify messages, the network
MUST respond with either ACK or REJ, and then of course there is
graceful call disconnect and clearing. Likewise in the case of vty-
initiated "hang up" of these test calls, you will also need to send CC
DISCONNECT toward MS and then follow subsequent graceful call clearing
sequence. I invite you to look at the source for themwi-test-mtc as
an example.
Looking at the code in OsmoMSC, it looks to me like a lot of work to
implement the above, given that the current code merely translates
between A interface CC messages and MNCC.
M~