how can osmo-mgw send a dummy RTP packet before CRCX ACK?
in CRCX processing of handle_create_con(), we send a dummy packet even before we have responded with the CRCX response. This seems rather odd, as we normally don't yet know the rermote IP/Port, as they might just be passed by the MDCX.
The transmission of dummy packet(s) would only make sense once we have verified that both local and remote ip/port are known to both sides. Am I missing something?
#1 Updated by dexter almost 3 years ago
in protocol.c: send_dummy() is called from handle_create_con(). This generates the early dummy packet. Its indeed odd. It would only make sense for CRCX requests that already include the remote address, otherwise we should be silent, the next chance to send the dummy packet would be the MDCX then.
#2 Updated by pespin over 1 year ago
In some cases (BSC CN-side), we already know the remote during CRCX, and we don't use MDCX there. So in that case it makes sense to send the dummy packet at the same time when we send the CRCX ACK, not matter if found before or after the CRCX ACK by the MGCP client.