MSC is not sending a payload_type to MNCC?
The SDP created by osmo-sip-connector is invalid:
Freeswitch rejects this.
Looks like the MSC is sending 0 for payload_type.
See mncc.c:check_rtp_create() in the sip cxtr
This works with legacy nitb:
You get this line in sip-connector's debug log:
mncc.c:393 RTP cnt leg(5010) ip(172.16.0.15), port(16412) pt(3) ptm(768)
With osmo-msc it will be:
mncc.c:393 RTP cnt leg(5010) ip(172.16.0.15), port(16412) pt(0) ptm(768)
let me copy the dirty hack mentioned on the ML here for later reference
(I haven't tested but wanted to find this if I need it.)
a quick and dirty hack for the osmo-sip-connector, to (probably) get your calls running through FreeSwitch: Hardcode override the pt in sdp_create_file() in sdp.c by adding other->payload_type = 98; (or for full rate GSM, it would be other->payload_type = 3;) somewhere in the top of that function, at line 170 for example, here: http://git.osmocom.org/osmo-sip-connector/tree/src/sdp.c#n170)
For 35c3 congress, this would be interesting to clarify...
#3518 would also bite us at congress methinks..
and there's also a workaround: