OpenBSC April 2025

openbsc@lists.osmocom.org

9 participants
20 discussions

pycrate repo update
by benoit michau 22 Jul '25

22 Jul '25

Dear osmocom developpers, This is just to let you know that the Python library pycrate has a new home : https://github.com/pycrate-org/pycrate. The packages on Pypi are now feeded from there. This library can be used in many cases dealing with mobile signalling. I wanted to let you know, as even if I am not aware of any osmocom projects depending on it, some of you may use the library from time to time, or could have local applications depending on it. Best Regards Benoit

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Re: Help with sccp library
by mosbah abdelkader 07 Jul '25

07 Jul '25

> I don't understand. This callback will be called with data you need to write > to the network. In case of MTP Level3 you will need to wrap that around the > msgb you got. I means: is the interaction with mtp3 layer implemented (is sending sccp data by mtp3 implemented by the library?)? Also, what about the reception of data from mtp3 layer. is that implemented in the sccp lib. I am asking these questions because I see the code of mtp3 in the lib but no significant call is present in the sccp part of the lib. Thank you for your help.

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Issues with writing adoc manual for contributed library
by Mychaela Falconia 27 Jun '25

27 Jun '25

Hello Osmocom community, Over the past several months I developed my own RTP endpoint implementation library (alternative to libortp), and I seek to get it merged into libosmo-netif so it can be used by OsmoBTS as an option: https://gerrit.osmocom.org/c/libosmo-netif/+/39280 https://gerrit.osmocom.org/c/libosmo-netif/+/39281 https://gerrit.osmocom.org/c/libosmo-netif/+/39291 I am now working on documentation, which I need to finish before I can lift these patches out of WIP in Gerrit. The last of the 3 WIP patches linked above is the one adding an adoc manual, built with the same tools as other Osmocom manuals, and I need some help with this one: 1) When I run './configure --enable-manuals' followed by 'make' on the Debian machine which Vadim provided to me for Osmocom documentation work, everything seems successful and I get a PDF rendering of my WIP manual. However, as soon as I uploaded this patch to Gerrit, I see a build failure in Jenkins. What am I doing wrong? I'm afraid that my knowledge of Autotools is not good enough to figure this one out. 2) My progress in writing the actual manual has reached the point where I need to insert some graphical diagrams showing the flow of RTP packets and the latency and jitter they experience in transit. I am thinking of one horizontal axis showing regularly spaced packets as they are emitted by the source, then forward-and-down arrows showing their transit with fixed or variable latency, then another horizontal axis below showing the receiver's view of time, with marked arrival times of packets (endpoints of latency arrows) and fixed-spacing times when the GSM or TDM system polls the jitter buffer. Question: what is the appropriate tool within the accepted Osmocom adoc suite for drawing such diagrams? If I weren't trying to get my RTP implementation accepted into Osmocom, I would have written this manual in troff on my favorite 1980s UNIX system, using pic preprocessor in the troff suite for graphical drawings like this one - but I reason that I need to write my manual within Osmocom documentation framework in order to maximize the chance of the associated code library being accepted into libosmo-netif, with follow-on patches to osmo-bts to use it optionally as an alternative to libortp. 3) When I do successful test builds on Vadim's Debian machine and get a PDF rendering of my WIP manual, the cover page in the PDF features both Sysmocom and Osmocom logos just like the mainstream Osmocom manuals, with Sysmocom logo on top. While this arrangement is probably appropriate for the existing manuals which were written predominantly by members of Sysmocom crew, it seems quite wrong for an external contributor's manual that does not contain a single sentence written by Sysmocom. How do I tweak things to remove that Sysmocom logo from the cover page, or even better, put San Diego 2G Association logo in its place? My contributions to Osmocom are directly linked to my efforts to build a new GSM network in San Diego, hence there is some symmetry between Sysmocom and SD2G in terms of Osmocom FLOSS project contributions, except for the rather big asymmetry in that SD2G is strictly non-profit. M~

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Possible Bug Issue - BAND_INDICATOR bit value is reversed
by Volkan Akkuş 27 May '25

27 May '25

Dear Sir/Ma'am, I kindly ask you to check on information below for a possible error. The claim is that the return bit value of the following function is reversed. It is supposed to be 1 instead of 0 and 0 instead of 1. https://gitea.osmocom.org/cellular-infrastructure/osmo-bsc/src/commit/2b718… Following sources are presented as proof for the claim. - Image_1 https://www.etsi.org/deliver/etsi_ts/145000_145099/145014/06.02.00_60/ts_14… - Image_2 https://www.etsi.org/deliver/etsi_ts/145000_145099/145014/06.02.00_60/ts_14… - Image_3 https://data.epo.org/publication-server/rest/v1.2/publication-dates/2016062… Thank you for your time and effort. Sorry if I have wasted your time. Volkan from Turkiye

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dynamic traffic channels
by Neels Hofmeyr 20 May '25

20 May '25

On Tue, Jun 28, 2016 at 10:05:28AM +0200, Harald Welte wrote: > [translated from german] > is it certain that we switch a channel to PDCH only when > gprs mode != none? A TS can be GSM_PCHAN_TCH_F_PDCH; those are the only ones for which we send a PDCH ACT message. We send a PDCH ACT message - during init (CHANNEL OML's state changed to enabled -> send PDCH ACT), - and upon channel release ack when pchan == GSM_PCHAN_TCH_F_PDCH. So the question is, when we receive a channel release ack, could that be the PDCH release and we switch PDCH right back on by accident? No, because we only receive a chan rel ack when the *TCH/F* is being released. That is because the PDCH release is initiated "internally" from the PDCH DEACT, and thus this condition in common/rsl.c rsl_tx_rf_rel_ack() catches on, which existed before dyn PDCH: if (lchan->rel_act_kind != LCHAN_REL_ACT_RSL) { LOGP(DRSL, LOGL_NOTICE, "%s not sending REL ACK\n", gsm_lchan_name(lchan)); return 0; } In rsl_rx_rf_chan_rel() the rel_act_kind is set to LCHAN_REL_ACT_RSL, but not in the rsl_rx_dyn_pdch(). This is analogous to the ip.access way -- the ip.access nanobts replies to a PDCH DEACT with a PDCH DEACT ACK and doesn't send a separate channel release ack. Maybe we could set rel_act_kind to some new LCHAN_REL_ACT_IPAC_DYN_PDCH for clarity? (But we shouldn't actually send a release ack, to stay compatible.) Even though it works as-is, we should indeed add another flag check: - We do check the flags that no ACT/DEACT is already pending; - And we do send a PDCH DEACT only if ts->flags & TS_F_PDCH_ACTIVE; - But we would send a PDCH ACT despite ts->flags & TS_F_PDCH_ACTIVE. This should never happen, but it would make sense to ensure that. ~Neels

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How to Uniquely Identify SCCP CO Sessions Over M3UA/SCTP?
by nmdbzk＠gmail.com 25 Apr '25

25 Apr '25

Hello community! I'm currently exploring the inspection of BSC/RNC<->MSC signaling traffic. At this stage, I'm focusing on dissecting SCCP connection-oriented (CO) signaling carried over SCTP (with multi-homing and multi-streaming) and M3UA. I'd appreciate any insights or suggestions. To uniquely identify individual SCCP virtual connections in a traffic dump, I'm using parameters like SLR/DLR (from CR, CC, DF1, RLSD, and RLC messages), along with lower-layer protocol details: SCTP ports, stream ID, M3UA OPC/DPC, and SLS. However, this parameter set doesn't always guarantee uniqueness—some SCCP connections appear to share the same values, leading to mix-ups, such as DTAP CC and SMS messages being interleaved. What additional indicators could I use to reliably distinguish SCCP connections? Or how do MSCs and BSCs typically differentiate and route them?

1 0

Bug Issue - BAND_INDICATOR bir value is reversed
by Volkan Akkuş 24 Apr '25

24 Apr '25

Dear Sir/Ma'am, I kindly ask you to check information below for a possible error. The claim is that the return bit value of the following function is reversed. It is supposed to be 1 instead of 0 and 0 instead of 1. https://gitea.osmocom.org/cellular-infrastructure/osmo-bsc/src/commit/2b718… Following sources are presented as proofs for the claim. - Image_1https://www.etsi.org/deliver/etsi_ts/145000_145099/145014/06.02.00_6…

1 0

LMSDevice / Bug 5338 : Power parameters requested before Tx Frequency
by jheyrendt.ext＠orange.com 23 Apr '25

23 Apr '25

Hi Sorry (perhaps it is not the right diffusion list) but We work with Osmocom with happyness and, after upgrading Debian packages AMD64, we encounter this error, and We can see that a bug has been opened. Do you know how to correct this ? in the configuration file ? or Do we have to wait for a package upgrade ? Many thanks in advance Best regards Yann 5338 OsmoTRX Bug New Normal LMSDevice.cpp:261 Power parameters requested before Tx Frequency was set! Providing band 900 by default... 03/11/2025 07:48 PM

1 0

Running hardware without internet- Setup information
by Ben Butter 08 Apr '25

08 Apr '25

Hello. So I'm trying to grasp all of these concepts. Is there a setup that doesn't require wifi to use for a cellular network after building setup? I want to use this without internet. Is that covered on any of your materials? Could you point me in the right direction? Would that be RAN?

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[libosmocore] testsuite: 61 87 failed on s390x
by Jaroslav Škarvada 08 Apr '25

08 Apr '25

Hi, I built libosmocore head (commit 84dcf73625513af44e711b2c99e21ee2c33b7eff at that time) on Fedora 43 (rawhide) and on s390x 4 tests failed. Iit's s390x running in qemu on x86_64, but it also fails on native s390 - there I saw failures of tests 25 26 69 90 (unfortunately I don't have the log from the native run). So probably more tests can coredump, to see all the problematic tests, it would probably require running through the valgrind. I am reporting it according to the provided instructions thanks & regards Jaroslav

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OpenBSC April 2025