Cellular Network Infrastructure » OsmoMGW

The MGW endpoint config is
src: VND.3GPP.IUFP
dst: AMR

and we are receiving an IuUP packet that should be converted to AMR/RTP.
osmo-mgw logs this line:

20221018235045922 DRTP DEBUG endpoint:rtpbridge/2@msc can not patch PT because no suitable egress codec was found. (mgcp_network.c:1174)

It reads like an error message, though it does not actually abort sending the RTP packet.
Rather, this log message shows that another mapping attempt is made, which is wrong:

This call to mgcp_send() is from bridge_iuup_to_rtp_peer(),
which means that the payload type is already set correctly for the dst_conn.
Attempting to map the payload type again compares a dst side payload type nr to the src side,
which may randomly match anything, translate to anything else on the dst side
and end up using a wrong payload type nr in the RTP packet sent out.

20221018235045922 DRTP DEBUG (rtpbridge/2@msc I:F002CA7A) RTP: rx 47 bytes from 192.168.10.155:40010 (mgcp_network.c:1468)
20221018235045922 DRTP DEBUG (rtpbridge/2@msc I:F002CA7A) msg ctx: 0 0x61e000002678 02 00 9c 4a c0 a8 0a 9b 00 00 00 00 00 00 00 00  (mgcp_network.c:1494)
20221018235045922 DRTP DEBUG (rtpbridge/2@msc I:F002CA7A) rx_rtp(47 bytes) (mgcp_network.c:1525)
20221018235045922 DLIUUP DEBUG IuUP(F002CA7A)[0x6120000630a0]{SMpSDU_Data_Transfer_Ready}: Received Event IuUP-DATA-ind (iuup.c:924)
20221018235045922 DLMGCP DEBUG Convert IuUP -> AMR: ft 7, len 31 (mgcp_iuup.c:273)
20221018235045922 DRTP DEBUG endpoint:rtpbridge/2@msc delivering RTP packet... (mgcp_network.c:1159)
20221018235045922 DRTP DEBUG endpoint:rtpbridge/2@msc can not patch PT because no suitable egress codec was found. (mgcp_network.c:1174)
20221018235045922 DRTP DEBUG endpoint:rtpbridge/2@msc transcoding disabled (mgcp_network.c:415)
20221018235045922 DRTP DEBUG endpoint:rtpbridge/2@msc process/send to 1 127.0.0.6 rtp_port:10004 rtcp_port:10005 (mgcp_network.c:1237)
20221018235045922 DRTP DEBUG sending 44 bytes length packet to 127.0.0.6:10004 ... (mgcp_network.c:1065)