OpenBSC February 2025

openbsc@lists.osmocom.org

8 participants
11 discussions

Issues with writing adoc manual for contributed library

by Mychaela Falconia

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~

1 week, 2 days

cmd2 update causing pySim-shell to fail

by bryan coxwell

Hi all, Just wanted to share an issue and a quick workaround I found for it in case anyone else has the same problem. I believe a cmd2 update is causing pySim-shell to fail. After installing it on a fresh install of Ubuntu Server 20.04 and getting the following error when I run "python3 pySim-shell -p0": >Using PC/SC reader interface >Autodetected card type: sysmoUSIM-SJS1 >AIDs on card: > USIM: a0000000871002ffffffff8907090000 >Traceback (most recent call last): > File "pySim-shell.py", line 512, in <module> > app = PysimApp(card, rs, opts.script) > File "pySim-shell.py", line 59, in __init__ > super().__init__(persistent_history_file='~/.pysim_shell_history', allow_cli_args=False, use_ipython=True, auto_load_commands=False, command_sets=basic_commands, >startup_script=script) >TypeError: __init__() got an unexpected keyword argument 'use_ipython' If you run into this you can fix it by uninstalling cmd2 and reinstalling cmd2 with "pip3 install cmd2==1.5". Best, Bryan

1 week, 5 days

Re: Help with sccp library

by mosbah abdelkader

> 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.

1 month, 1 week

dynamic traffic channels

by Neels Hofmeyr

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

1 month, 2 weeks

Adding doxygen style comments to header files

by Alexander 'lynxis' Couzens

Hi, it came up again in gerrit again. Currently the osmocom style states doxygen style comments should be done in the .c file. Doxygen are those comments: /*! a brief description of the function * \param something Some description of the use * \return 0 if ... */ Doxygen takes those comments and generates a html documentation of the code. I would like to change it to have those in the headers files instead (when the function in included in a header file). When using the doxygen comments only for doyxen, for sure, there isn't a difference between having it in .c or in .h files. But when using IDEs or language servers, they usually only parses headers files and the .c files of the current active project (e.g. osmo-sgsn), but not the .c files of other projects (libosmocore). On the downside I only see the problem of increasing the size of header files, but I don't see an issue in here. Any thoughts? Best, lynxis

4 months

certificate bypass in osmoepdg

by subhajit.chatterjee

Hi, I was going through the features of osmoepdg solution and thought to ask few questions regarding the implementations. 1. In most of deployment tunnel authentication is bypassed. So, even if UE send CERTREQ, it is getting ignored at ePDG. ePDG also doesn't send anything to UE. Do you have any idea of how to implement that in strongswan or have you explored that earlier? I saw that in 3gpp 33.402 and RFC 5996, certificate things are optional. However, I know that strongswan authentication is tightly coupled, so just trying understand if you have already bypass it by doing any changes in strongswan or atleast know how it should be done. 2. There are many error and status codes written in ePDG standard 24.302 clause 8. Have you mapped all EPC core error to corresponding IKEv2 error or status codes? Thanks & Regards Subhajit Chatterjee New Delhi

4 months, 2 weeks

BSC graceful shutdown

by Sipos Csaba

Dear List, With Domi we are working on some improvements on the Nokia Site E1 based BTS types, mainly focusing on the OML side. Among many things (see the upcoming patches), one thing we would like to add is to lock all TRX-es at BSC shutdown. The OML command structures we already have, but when we added this part to the shutdown_om() function we noticed that only the first TRX receives the command, the rest does not. When we looked at the E1 capture even more surprise: the capture file lacks the OML command of the first TRX which we locked successfully (cross checked with BTS manager). Enabling LAPD debug also indicates that there is no graceful shutdown of the lapd links as well, which is my suspicion for the failing locking of TRXes except of TRX1: the connection is just cut before the last couple TRX lock commands can pass and we got just lucky with the first one timing-wise. I think Harald or Pau mentioned a new FSM which is likely not implemented/backported for the Nokia BTS variant. The question is: does the new FSM does a graceful shutdown or maybe handles it better than the current code? I looked at the rbs2000 as an example also but I don't see that the shutdown part is handled any different/ better. At this point I have no idea if this is the expected behavior, a bug or a missing feature? The fact we are missing an OML message in the PCAP which clearly passed the E1 line kind of indicates a bug at least there. I am not sure but likely other BTS types might also benefit from a graceful shutdown (eg. at least lock all TRXes). The Nokia variants clearly do: without the TRXes locked, at the next BSC startup all the unlocked TRXes inadvertently start random RSL bootstraps, even in the middle of a site reset, filling the log with random errors. Please let me know if there is any example code we should look at, and/or what your opinion is about this subject in general. Regards, Csaba

4 months, 2 weeks

EFR and AMR voice calls

by Sipos Csaba

Dear list, FR calls between mobile phones are working fine, but when I change the codec-list to "codec-list fr2 fr1 fr3" or "codec-list fr3 fr1 fr2", I am getting a Remote Transcoder Failure: lchan(0-0-1-TCH_F-0)[0x630d01c78b80]{ESTABLISHED}: (type=TCH_F) CONNECTION FAIL (cause=Remote Transcoder Failure [ 28 ]) In the BSC config: codec-support fr efr amr codec-list fr2 fr1 fr3 In the MSC config: mncc-int default-codec tch-f fr default-codec tch-h hr Both the phones and the BTS is FR/EFR/AMR capable. I am fairly sure with Osmo-NITB at least EFR was working with these phones and BTS some years ago. If needed, I can provide a pcap. If someone has an idea, please let me know. Regards, Csaba

4 months, 4 weeks

The Importance of Freight Forwarding Service for My Manufacturing Business

by olivianaylor322＠gmail.com

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5 months

The Importance of Freight Forwarding Service for My Manufacturing Business

by olivianaylor322＠gmail.com

As the owner of a manufacturing business, I’ve come to realize how crucial efficient logistics are. When I first started exporting products overseas, handling shipping on my own was a constant struggle. After partnering with a <a href="https://www.cfipak.com/">freight forwarding service</a>, everything changed. They handle the complexities of shipping, customs, and delivery, allowing me to focus on production and growth. With their expertise, my shipments are now timely and cost-effective. If you're in manufacturing or any business with global reach, investing in a freight forwarding service will save you time and stress, helping your business thrive.

5 months

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OpenBSC February 2025