OpenBSC January 2026

openbsc@lists.osmocom.org

23 participants
36 discussions

Re: AMR on E1 BTS with tw-e1abis-mgw
by Sipos Csaba 17 Apr '26

17 Apr '26

Hi Mychaela, The AMR capability works great with your drop-in MGW implementation, voice quality improved a lot. I also tested the FR/EFR part earlier, which also works as expected. CSD is definitely interesting, once I have at least two CSD capable devices, I will give that a try as well. We already tried with a Nokia MetroSite, and early next year I am planning to try with our UltraSite setup at the museum as well. Would be nice to be able to send fax on top of GSM :-) The OML dialect we have in Osmocom now (called "nokia_site") despite its name it supports old Nokia equipment up to Felxi EDGE, Multiradio and Multiradio10 (on E1), if anyone else is interested, so OML support is not limited to just the Nokia *Site family. Some of this stuff is still running in less fortunate countries... Little bit of tweaking will likely needed, but at least it is not a completely unknown part like AoIP. Regards, Csaba

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Need nano3G (S8 - Model 237A)
by Akib Sayyed 16 Apr '26

16 Apr '26

Dear List I am extremely sorry for off the topic question. I am willing to buy nano3G Nodeb. Is anyone in list have spare which can be sold. Please let me know. -- Akib Sayyed Matrix-Shell akibsayyed(a)gmail.com akibsayyed(a)matrixshell.com Mob:- +91-966-514-2243 <https://www.avast.com/sig-email?utm_medium=email&utm_source=link&utm_campai…> Virus-free. www.avast.com <https://www.avast.com/sig-email?utm_medium=email&utm_source=link&utm_campai…> <#DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2>

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Front and back sides of an MSC
by Mychaela Falconia 16 Apr '26

16 Apr '26

Hello Osmocom community, I have a question about terminology that is not really specific to Osmocom, but is specific to GSM/3G/etc cellular industry, or whatever is left of it. An MSC in a GSM or 3G or any other circuit-switched cellular network has two sides: one side facing the RAN (A interface in GSM, IuCS in 3G), the other side facing PSTN or ISDN or BICC or SIP-I or whatever the fixed telephone network may be. My question: is there a general industry-wide agreement as to which side should be called the front and which should be called the back? To me it seems intuitive to refer to the A/IuCS side of an MSC as the front and the PSTN/ISDN/BICC/SIP-I side of the same MSC as the back. However, I am just one person, and I have no idea whether or not my view is intuitive to others. And it would even worse if the opposite convention happens to be widely used... Hence I am asking this community, in the hope that someone with more industry experience would know how telco network engineers casually refer to RAN-facing and fixed-network-facing sides of an MSC. For a long time I had the idea of building ThemWi MSC as a modular system (multiple processes talking to each other via sockets) with a stripped-down OsmoMSC derivative as the "central" component, and with a radically different placement of MSC-MGW. However, as I started working on more detailed design, I realized a major flaw in my originally envisioned architecture: my original approach to MSC-MGW would break TFO for AMR, specifically the dialogue between TFO-aware BTS and the TRAU equivalent in the MGW. I am now spinning a new architecture in my head, one which tentatively includes two dissimilar MGWs in the MSC. If my front vs back terminology is valid, then the front MGW (talking to AoIP user plane) would perform speech transcoding but become a transparent pass-through for CSD (basically a software-only, IP-based equivalent of a hardware TCSM colocated at the MSC site), while the back MGW would be a transparent pass-through for speech calls, but turn into a complex IWF for CSD. This tentative architecture exactly matches the placement of speech transcoding and CSD IWF functions in traditional hardware MSCs of TDM-based, before-AoIP world. But I need to know if I should keep these front and back terms, or swap them the other way around. M~

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Splitting out M3UA and MTP3 out of Open BSC into a separate library
by Arran Cudbard-Bell 15 Apr '26

15 Apr '26

Hi, Developing a module for FreeRADIUS to support EAP-SIM and EAP-AKA authentication against a HLR. The HLR we were targeting only supported a SCTP/M3UA/SCCP/TCAP/MAP stack, so we couldn't use SUA. Ripping the M3UA/MTP3 code out of OpenBSC worked surprisingly well. We ended up running the event loop in a separate thread to work around the threading issues. Unfortunately the HLR implements the ANSI variant of everything, whereas OpenBSC and supporting libraries seem to have been written to be compatible with the ITU standards. ...but the differences are fairly minor at MTP3 and SCCP layers, and i've started work on a patchset for libosmo-sccp. https://gerrit.osmocom.org/#/c/73/ Anyway, trying to gauge interest in splitting those layers out of Open BSC into a separate library, would be happy to take on M2UA as well for consistency. It would almost certainly get more projects using the code. There's very little out there even in Perl land for working with SS7. Thanks, -Arran Arran Cudbard-Bell <a.cudbardb(a)freeradius.org> FreeRADIUS Development Team FD31 3077 42EC 7FCD 32FE 5EE2 56CF 27F9 30A8 CAA2

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GSM Silent call
by samir 15 Apr '26

15 Apr '26

Hi, I have read that silent-calls in GSM can be used to make a call to a target MS and listen to it without having the target knowing it. Is this theoretically possible ? If yes, can it be done in OpenBSC ?

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[PATCH 4/4] core/conv: Add optimized Viterbi decoding
by Vadim Yanitskiy 15 Apr '26

15 Apr '26

Hi Tom and all, After a quick look at the 4th patch, related to your optimized Viterbi decoder, I have noticed that currently the convolutional code definitions from the 'src/gsm/gsm0503_conv.c' are out of the 'tests/conv' test coverage... So, I would like to extend the test coverage. All I need are the test vectors, which I'll add to existing ones. Some of them I already found in your 4th patch, but some pending I need to write myself. Right now I have a simple question... Let's look at one example: { .name = "GSM RACH (non-recursive, flushed, not punctured)", .code = &gsm_conv_rach, .in_len = 14, .out_len = 36, // ??? .has_vec = 0, .vec_in = { }, .vec_out = { }, } As I noticed, the 'in_len' may be taken from the code definition: const struct osmo_conv_code gsm0503_rach = { .N = 2, .K = 5, .len = 14, // The 'in_len' is here! .next_output = xcch_output, .next_state = xcch_state, }; But I don't know how to calculate the 'out_len'... Could you please give me some hint? I already started to work on your 4th patch: https://gerrit.osmocom.org/1542 https://gerrit.osmocom.org/1543 With best regards, Vadim Yanitskiy.

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ip.access nano 3G S8 Configuration
by John Thewlis - Meath Broadband 10 Apr '26

10 Apr '26

We are trying to setup this AP as part of the 3.5G Osmocom project. We have the software stack operational and are now preparing the nano for testing. When we try to login via telnet at port 8090 we are getting a constant refusal to connect:- root@osm/openbsc/openbsc/src/ipaccess# telnet 192.168.192.30 8090 Trying 192.168.192.30... telnet: Unable to connect to remote host: Connection refused The device seems to be locked as indicated by the leds on the front panel. We have tried resetting the nano to see if this would help but to no avail. Any ideas as to how to access the device for initial configuration?. Thanks John

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Is It Worth It to Pay Someone to Take My Online CompTIA Exam?
by olivianaylor322＠gmail.com 09 Apr '26

09 Apr '26

I’ve been struggling with my CompTIA exam prep and honestly, it's been hard to manage everything. The idea of asking someone to take my online CompTIA exam for me https://www.theresearchguardian.com/take-my-comptia-exam-for-me/ seemed a bit extreme at first, but after seeing how many students do it, I’m starting to consider it seriously. If anyone has tried this service, I’d love to hear your thoughts. Was it worth the investment? How reliable were the test takers? I just want to make sure I'm making the right choice.

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Managing Complicated Laws in BSC Implementations
by Fennellmarian018＠gmail.com 09 Apr '26

09 Apr '26

The complexities of Base Station Controller (BSC) integration in open-source mobile networks have presented me with a number of overlapping areas pertaining to telecommunications legislation and regulatory compliance. In order to better comprehend how international legal standards affect open BSC installations in various jurisdictions, this intersection has unanticipatedly prompted me to seek [url=https://dissertationwritinghelp.uk/law-dissertation-help/]law dissertation help[/url]. I would love to hear from anyone else who has studied legal issues in their OpenBSC-related academic or practical work, as well as suggest some books.

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Artvigil Australia: A Trusted Solution for Enhanced Focus and Wakefulness
by csheldon756＠gmail.com 31 Mar '26

31 Mar '26

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OpenBSC January 2026