Neels,

A reason could be that osmo-trx is losing connection with the SDR. Are you running this on bare metal or a VM?

USB based SDRs like USRP B2x0 have hard time keeping the Tx/Rx alignment when there are any disturbances. So osmo-trx features a sophisticated algorithm to maintain this alignment for USB based devices. Thomas has spent tremendous effort tuning it to perform well, but may be there are edge cases which are not handled there yet. Let's wait for his comments.

(That's one the primary reasons we use Ethernet in UmTRX, btw - it's much more robust to issues like this)

Please excuse typos. Written with a touchscreen keyboard.

--
Regards,
Alexander Chemeris
CTO/Founder Fairwaves, Inc.
https://fairwaves.co

On Jun 14, 2017 04:34, "Neels Hofmeyr" <nhofmeyr@sysmocom.de> wrote:

Hi Tom and others,

in our testing setup, we have sporadic failures (~2 out of 10 times) with:

DOML <0001> bts.c:208 Shutting down BTS 0, Reason No clock from osmo-trx

What would be possible reasons for this failure, and how can we go about fixing
it? Some more logging around it:

20170614032014399 DRSL <0000> rsl.c:2333 (bts=0,trx=0,ts=0,ss=2) Fwd RLL msg EST_IND from LAPDm to A-bis
20170614032018533 DL1C <0006> scheduler_trx.c:1451 PC clock skew: elapsed uS 4136730
20170614032018533 DOML <0001> bts.c:208 Shutting down BTS 0, Reason No clock from osmo-trx
20170614032018533 DL1C <0006> scheduler.c:240 Exit scheduler for trx=0
20170614032018533 DL1C <0006> scheduler.c:216 Init scheduler for trx=0
20170614032018533 DOML <0001> oml.c:280 OC=RADIO-CARRIER INST=(00,00,ff) AVAIL STATE OK -> Off line
[...]
Shutdown timer expired

(We're using an external 10MHz OCXO timing source)

It appears there's four seconds of nothing from osmo-trx?

Most curious is that the next run will be completely fine, until some time
later we get this same failure.

We wait until osmo-trx logs

-- Transceiver active with 1 channel(s)

and then we "immediately" or up to a second later launch osmo-bts-trx. Would it
help to give it more grace time??

Thanks!

~N