Dear All,   I am running a GSM stack:   osmo-stp smo-msc osmo-hlr osmo-bsc osmo-bts-trx osmo-trx-lms   It seems that my transmitter is emitting radio-waves into air (osmo-bts-trx and osmo-trx-lms communicate with each other through ports 5702 / 5802 — pls see attached printscreen), however i could not make GSMTAP tracing. Osmo-bts-trx does not send GSMTAP messages to port 4729.   In most recent version of osmo-bts, GSMTAP tracing is arranged through config file:   bts 0   gsmtap-remote-host 127.0.0.1   gsmtap-sapi ccch     I could not run the GSMTAP tracing even in previous verions of osmo-bts where you have to specify in synopsis when you call a program:   /usr/bin/osmo-bts-trx -s -c /etc/osmocom/osmo-bts-trx.cfg --gsmtap-ip 127.0.0.1     I thought may be i am having some issues in stack components behind osmo-bts for example in osmo-bsc or behind and i tried to run virtual bts. When i tried to run osmo-bts-virtual GSMTAP messages were visible in wireshark (please see attached file osmo-bts-virtual), therefore bts-bsc communication is good.   However I still could not figure out why my osmo-bts-trx does not send GSMTAP messages. Or would you advise what log might be helpful to see what i am doing wrong ….   Thank you for your always helpful assistance   -- Mario Lucas   ----------------------------------------------------------------------   -- Mario Lucas