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)
#3 Updated by neels about 2 years ago
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)
#4 Updated by keith about 2 years ago
For 35c3 congress, this would be interesting to clarify...
#3518 would also bite us at congress methinks..
and there's also a workaround: