osmo-nitb/osmo-bts-trx: Logging traffic on A-bis interface

Hi all, I wanted to check if the bts - bsc communication works properly with my configuration. For example, if my osmo-nitb does send the system information messages to the bts. I tried the vty logging interface of osmo-bts and logged some messages, but they were not the messages I expected. I configured the groups rsl, oml, rll, rr and abis to "notice", all to "everything" and everything else to "error" and got following log output (lots of these and nothing else): ... <0006> scheduler.c:405 PH-RTS.ind: chan=CCCH chan_nr=0x90 link_id=0x00 fn=993588 ts=0 trx=0 <0006> scheduler.c:341 PH-DATA.req: chan_nr=0x90 link_id=0x00 fn=993588 ts=0 trx=0 ... PH-RTS.ind and PH-DATA.req seem to come from layer1 SAP, the osmo-trx and have probably nothing to do with the SI messages. Is traffic on abis generally not logged or is my log config faulty? I ended up configuring the gsmtap interface for osmo-bts and could so see the uplink/downlink in wireshark and could see that the SI information is properly sent. But gsmtap only works for the air interface. What is the best way for logging/sniffing the communication on the A-bis interface? With kind regards, Sebastian Stumpf