Hi Kristian,
On Wed, Dec 07, 2016 at 05:52:15PM +0100, Kristian Martens wrote:
two UEs (A and B) are successfully registered in a network. Now A tries to call B. B is paged by the core via A interface but the sysmoBSC/BTS does not seem to page the UE (or UE does not answer paging). What could be the reason for this behaviour? How could the problem be debugged? Please find the attached pcap for your reference.
Most important is to find out what is actually happening on the air interface vs. the Abis interface.
If you have an air-interface protocol tracer, or are familiar with OsmocomBB, or you have a phone with Qualcomm DIAG + QXDM, or a Sagem OT phone, etc. you could get a protocol trace of the phone side. This is the most reliable method to know what arrives at the phone or not.
Next best to that, you can enable GSMTAP generation in osmo-bts, which I believe is sufficiently documented in the manual. Using that, particulary for the PCH L1 SAPI, you will get a 'pseudo air interface trace' consisting of anything that the BTS hands to the PHY for transmission.