Dear baseband developers team, I built home gsm network with Osmo-stp-msc-hlr-bsc-bts, osmo-trx limeSDR. I managed and registered phones. I did send sms between each other. However when i decided to make a call — i noticed following message in terminal: «PCU socket not connected, dropping message». I searched on Osmocom web site and it is said that pcu socket is involved in GPRS things (i.e. in internet). Therefore why does such message appears when i try to make simple call between two mobiles — it has nothing to do with GPRS… And what would you advise me how to resolve this ? P.S. initially when i was about to start osmo-bts-trx i got message «PCU L1 socket failed» and i just renamed the pcu_bts file to some other name and osmo-bts-trx started. Thank you so much for your kind reply. Best regards -- Mario Lucas
Hi,
Indeed PCU is in charge of handling PDCH timeslots which are related to GPRS.
"pcu_bts" is not a regular file, is a unix domain socket which is used to interconnect osmo-bts-trx and osmo-pcu. So having failures there means you either have a configuration problem (path incorrect configured) or a permission/ownership problem, maybe because you run osmo-bts-trx or osmo-pcu with root and the other with regular user, so the unix domain socket is created with permissions which the other process cannot then use.
So, assuming you don't have issues BTS<->PCU issues and everything's fine, seeing "PCU socket not connected, dropping message" could mean PCU crashed at that time and is no longer available. When you start a phone call there may be PCU related traffic because the MS was probably doing data transfers in PDCH timeslots until the exact moment when you page the MS and ask it to go for a call, so the MS needs to "suspend" the GPRS use and notifies the network.
baseband-devel@lists.osmocom.org
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Mario Lucas -
Pau Espin Pedrol