osmo-nitb and osmo-bts-trx problems with voice, no connection (using LimeSDR)

This is merely a historical archive of years 2008-2021, before the migration to mailman3.

A maintained and still updated list archive can be found at https://lists.osmocom.org/hyperkitty/list/OpenBSC@lists.osmocom.org/.

Osmocom Mailing List osmocom at lains.me
Fri Feb 16 20:07:28 UTC 2018


Hi,

Can I see your configuration files? Particularly the OsmoNITB (OpenBSC) 
one.

Here's mine: 
https://gist.github.com/FFY00/ea5fa36435bc31d3d3a02ff3e46abb50

Thanks,
Filipe Laíns <https://github.com/FFY00>

On sex, fev 16, 2018 at 1:14 PM, Pau Espin Pedrol <pespin at sysmocom.de> 
wrote:
> Hi,
> 
> I'm also experincing this issue while using limesdr, also using 
> latest dependencies (soapysdr, limesuite, etc.) and latest osmo-trx.
> 
> The call is established correctly, but after a few seconds (or almost 
> immediately) it is cancelled.
> 
> This explains that the call was closed:
> 
> > <0000> rsl.c:689 (bts=0,trx=0,ts=3,ss=0) Sending Connection Failure:
> > cause = 0x01
> > <0011> lapdm.c:1144 ((nil)) RLL Message 'REL_REQ' received without 
> LAPDm
> > context. (sapi 0)
> > <0000> rsl.c:1433 (bts=0,trx=0,ts=3,ss=0) Sending RTP delete 
> indication:
> > cause = Normal event, unspecified
> 
> The RTP becoming out of sync most probably also explains too that a 
> lot of packets are not being received correctly at l1sap layer:
> 
>> <000e> l1sap.c:96 RTP clock out of sync with lower layer: 1600 vs 
>> 160 (2295960->2296003)
>> <000e> l1sap.c:96 RTP clock out of sync with lower layer: 82594400 
>> vs 160 (2296003->2295973)
>> <000e> l1sap.c:96 RTP clock out of sync with lower layer: 1440 vs 160
> 
> Reproducing a conversation relarted to this topic that I had with 
> Harald, but unfortunately didn't have time to continue on it yet:
> 
> * Pau:
> It seems it comes from osmo-bts l1sap_ph_data_ind with len(msgb)==0, 
> indicating a bad frame. I can reproduce this every time I place a 
> call between 2 MS with a limesdr.
> 
> * Harald:
> well, it's not "a bad frame", but it's a lot of ongoing bad/lost
> signaling blocks.
> 
> So first of all, this entire code path is not traversed for voice 
> (TCH)
> block, only for signalling (FACCH/SACCH) blocks. And then, there's the
> 's' counter implementing the radio link criterion. It is not formally
> specified for the BTS side (see TS 45.008 Section 5.3), but we simply
> implement what's specified for the MS side in TS 45.008 Section 5.2.
> 
> "S" is incremented for every good block by two, and decremented for
> every bad block. And once it reaches a negative value, the
> above-mentioned LINK FAILURE message is sent via RSL. See
> 
> So you must be loosing more than 66.6% of your total number of 
> signaling
> blocks to ever reach this point.
> 
> How do the measurement reports look like? Those are the most valuable
> resource when debugging anything related to RF link issues.
> 
> 
> --
> - Pau Espin Pedrol <pespin at sysmocom.de>         
> http://www.sysmocom.de/
> =======================================================================
> * sysmocom - systems for mobile communications GmbH
> * Alt-Moabit 93
> * 10559 Berlin, Germany
> * Sitz / Registered office: Berlin, HRB 134158 B
> * Geschaeftsfuehrer / Managing Director: Harald Welte


Sent via Migadu.com, world's easiest email hosting
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.osmocom.org/pipermail/openbsc/attachments/20180216/bc562b09/attachment.htm>


More information about the OpenBSC mailing list