Hi,
I am trying to setup a simple Network In The Box 2G network. I am only interested in CS capabilities (voice calls, SMS, USSD). I am currently running the following elements with the default configurations:
- osmo-bts-trx (connecting to osmo-trx-uhd driving a USRP B205mini-i)
- osmo-bsc
- osmo-msc
- osmo-hlr
- osmo-mgw
- osmo-stp
I built all the programs from source on Ubuntu 22.04. Everything is running locally on one machine.
Everything seems to function correctly at first, but I noticed that sometimes when I try to execute an USSD code or make a call, my Channel Requests are not being responded. I noticed when this happens, osmo-bts shows the following notice:
DPCU notice PCU socket not connected, dropping message (pcu_sock.c:1018)
As I understand from the documentation (https://osmocom.org/projects/cellular-infrastructure/wiki/Osmocom_Network_I…), this component is not required for circuit switched services as the ones I am requesting, so I do not understand why this is happening. I assume something in the configuration files is telling the BTS or some network element that the PS side of the network is active, but I haven't found anything related to PCU in any of configuration files.
