Hi I'm still trying to run OpenBSC against a legacy MSC. All is fine, except rtp/mgcp stuff. All other procedures are performed well. Call set up is done properly, both BSSAP and MGCP. At downlink direction, GSM-FR coded messages are reaching endpoints at BSC side, and that's all: no RTP traffic between BSC and BTS. And I also found no control traffic in between osmo-bsc_mgcp and osmo-bsc or BTS Could you please give me a key. I would appreciate your help, and would be glad to write a wiki afterwards. osmo-bsc is configured with --enable-osmo-bsc the only trick here I had to do - to allow GSM FR (version 1) manually, there is a temporary patch to osmo-bsc: could not configure it from a file. Btw, what is the reason to keep such sort of knowledge at BSC side, and what is the proper way to define permitted codecs? osmo-bsc_mgcp is running, answers MGCP commands, allocates endpoints etc. MGCP call setup is done properly, MGCP allocates endpoints at BSC side (at server), but there is no RTP traffic in between BSC and BTS. Thank you, Dmitri rtp path is as follows, all MGCP formalities are met (card) 192.168.50.10:4036 <--G.711--> 172.44.3.2:4036--(transcoding)-- 192.168.1.11:5036 <--GSM FR --> 192.168.1.11:16036 (osmo-bsc_mgcp) where (card) is A-nterface GW, (transcoding) is my software I'm getting an error <000b> mgcp_network.c:348 Endpoint 0x13 data from wrong address 192.168.1.11 vs. 0.0.0.0 CallAgent is at 192.168.50.10, interfaced over OpenVPN tunnel (172.44.2.XX) So, server has two interfaces: 192.168.1.11 and 172.44.3.2 (OpenVPN) BTS is 192.168.1.4 So, mgcp is bind to 0.0.0.0, cause MGCP is controlled over VPN interface mgcp.cfg is bind ip 0.0.0.0 bind port 2427 bind early 1 rtp base 4000 sdp audio payload number 3 sdp audio payload name GSM/8000 number endpoints 31 loop 1 osmo-bsc.fcg is e1_input e1_line 0 driver ipa network network country code 250 mobile network code 07 short name OsmoBSC long name OsmoBSC auth policy closed location updating reject cause 13 ! encryption a5 1 neci 1 paging any use tch 0 rrlp mode none mm info 1 handover 0 handover window rxlev averaging 10 handover window rxqual averaging 1 handover window rxlev neighbor averaging 10 handover power budget interval 6 handover power budget hysteresis 3 handover maximum distance 9999 timer t3101 10 timer t3103 0 timer t3105 0 timer t3107 0 timer t3109 0 timer t3111 0 timer t3113 60 timer t3115 0 timer t3117 0 timer t3119 0 timer t3122 0 timer t3141 0 dtx-used 0 subscriber-keep-in-ram 0 bts 0 type nanobts band PCS1900 cell_identity 2611 location_area_code 51601 training_sequence_code 7 base_station_id_code 63 ms max power 15 cell reselection hysteresis 4 rxlev access min 0 channel allocator ascending rach tx integer 9 rach max transmission 7 ip.access unit_id 1801 0 oml ip.access stream_id 255 line 0 neighbor-list mode manual-si5 gprs mode none trx 0 rf_locked 0 arfcn 800 nominal power 0 max_power_red 20 rsl e1 tei 0 timeslot 0 phys_chan_config CCCH+SDCCH4 hopping enabled 0 timeslot 1 phys_chan_config TCH/F hopping enabled 0 timeslot 2 phys_chan_config TCH/F hopping enabled 0 timeslot 3 phys_chan_config TCH/F hopping enabled 0 timeslot 4 phys_chan_config TCH/F hopping enabled 0 timeslot 5 phys_chan_config TCH/F hopping enabled 0 timeslot 6 phys_chan_config TCH/F hopping enabled 0 timeslot 7 phys_chan_config TCH/F hopping enabled 0 msc ip.access rtp-base 6000 timeout-ping 20 timeout-pong 5 dest 192.168.50.10 5000 0 CRCX 147 0012@mgw MGCP 1.0 M: sendrecv L: p:20, s: off, e: off, a: GSM C: 18 v=0 c=IN IP4 192.168.1.11 m=audio 5036 RTP/AVP 3 200 147 OK I: 6 v=0 o=- 6 23 IN IP4 192.168.1.11 c=IN IP4 192.168.1.11 t=0 0 m=audio 16036 RTP/AVP 3 a=rtpmap:3 GSM/8000