OpenBSC June 2023

openbsc@lists.osmocom.org

4 participants
16 discussions

code review
by Neels Hofmeyr 03 Jul '23

03 Jul '23

Hi community, I feel a bit frustrated by how code review is going recently at osmocom. Let me compare two larger feature branches: There are weeks of review on 19 patches in osmo-hnbgw/cnpool, and <24h from submit to merge on 14 patches in osmo-msc. That may in some situations be ok and justified, but I feel that it is not: The cnpool patch series for osmo-hnbgw spawned huge discussions and long delays on account of minor issues: log lines, event names and comments. I said so, yet it droned on and even spawned offspring. None of the important features was part of code review: larger design choices of the API, efficiency in handling the actual signalling, correctness of the signalling. Maybe that's because all those were mint perfect and no bugs anywhere, but I doubt that I'm really that good =) And at the same time I was "just now" asked to review some patches for osmo-msc, which changes an API that I have recently added and had ideas and reasons for. Before I get a chance to even glance, I see that all the patches are already merged! It is now basically too late to bring in my feedback, because the patches are in, and why spend more time on it. Suck it up, bygones. This very API that was being changed in osmo-msc in under 24 hours was itself under code review scrutiny for at least three years. Also I have (in my own free time) tried to get an improved logging timestamp into libosmocore. This is tagging along for years and years now, because every time over it is being blocked by minor details that are matters of taste. For years I lose precious moments every time i have to read an 'extended-timestamp' in osmo logging and identify the boundary of hours, minutes and seconds. This I consider important. AFAIR the reasons for blocking the patches were, objectively, all not important. These examples are starkly unbalanced. I'm sure you're aware of the bikeshed phenomenon -- it is a precise description of what is happening. It would be great if we could turn that around a bit? http://www.catb.org/jargon/html/B/bikeshedding.html Let's say, I know from experience that it is hard to give good code review, so count me in on this advice. Let's still give all the code review we can, but let's keep in mind the actual impact the particular code change has. If it goes in the "fringe detail" bucket, let's mention it, but just let it pass if the author disagrees. Hope you understand my frustration and maybe even agree. Thanks, ~N

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Nokia Site (Ultra, Metro)
by Sipos Csaba 30 Jun '23

30 Jun '23

Hi Neels, I checked RF and BB hopping with my MetroSite with my patch added, and they both seem to work, multi-TRX was tested a couple days ago, that also works with 2 TRXes. Obviously I did not tested every possible hopping scenarios, but in both cases the node manager reported the correct hopping states and I also checked with a spectrum analyzer. This means that either my UltraSite still has some issues, or that the config logic for it needs a bit of tuning. The one difference I have noticed is that the MetroSite does starts the RSL LAPD when the TRXes reach a configured state, while the UltraSite needs the BSC to start the RSL LAPD links even after the TRXes reach the same configured state. FYI, I am running exactly the same BTS SW release on both units (latest LTS ever released by the vendor), so they should not behave differently from a pure SW point of view. Anyway, at this point in time I don't see any particular issues that indicates a BSC problem. One feature missing is the ability to configure sectors (Nokia calls a sector a "BTS" while the base station is called "BCF"). My question is, do we have any BTS type that has sector configuration support so I can take a look how this was done (if any) ? Regards, Csaba

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BSC to multiple external MSCs
by Varoon Greedharry 22 Jun '23

22 Jun '23

Hello, I know it's quite a dummy question (Beginner) but I'm actually trying the BSC to two external MSCs but the attempt failed. As per the doc, I did configure the cs7 instance. Is there an example configuration file which I could go through. -- Best Regards, Varoon

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Re: OpenBSC Digest, Vol 104, Issue 1
by Sipos Csaba 21 Jun '23

21 Jun '23

Hi Neels, Sorry for the late response. As there is still a slight chance that the issue on my side is HW related, I digged out my old MetroSite with 4 TRX as that is a little bit smaller and easier to move compared to the Ultra cabinet :-) So I will conduct some tests with it in the next couple days. Lets say the issue is the same: what exactly do you need from me to maybe look into it? I assume E1 pcap and logs. If you have a specific log mask, or you need something else, please let me know. Regards, Csaba

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OsmoDevCall on Jun 21, 2023: FR/HR/EFR voice codecs in Osmocom RAN
by Harald Welte 21 Jun '23

21 Jun '23

Dear Osmocom community, we're happy to announce the next incarnation of OsmoDevCall. when: June 21, 2023 at 20:00 CEST where: https://osmocom.org/OsmoDevCall (Big Blue Button) This time, @falconia will be leading a discussion on FR/HR/EFR voice codecs in Osmocom RAN This meeting will have the following schedule: 20:00 meet + greet 20:10 topic as outlined above 21:00 unstructured supplementary social event [*] Attendance is free of charge and open to anyone with an interest in Osmocom or open source cellular technologies. More information about OsmoDevCall, including the schedule for further upcoming events can be found at https://osmocom.org/projects/osmo-dev-con/wiki/OsmoDevCall Looking forward to meeting you soon! Best regards, Harald [*] this is how we started to call the "unstructured" part of osmocom developer conferences in the past, basically where anyone can talk about anything, no formal schedule or structure. -- - Harald Welte <laforge(a)osmocom.org> http://laforge.gnumonks.org/ ============================================================================ "Privacy in residential applications is a desirable marketing option." (ETSI EN 300 175-7 Ch. A6)

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Nokia UltraSite
by Sipos Csaba 08 Jun '23

08 Jun '23

Hi Harald, I made some progress with the Nokia UltraSite and managed to fix its backplane, so at least I was able to continue with reintroducing hopping control with the first 2 TRX slots of the cabinet. During this process I realized that apparently even multi-TRX support is broken, which was working on the old OpenBSC codebase in 2016. If only the first TRX is configured the BTS bootstraps fine, but when a second TRX is configured, the unit goes into this weird state: the first TRX loops through configurng and waiting for LAPD states and stays in configuring state, while the second TRX is stuck ad supervisory state where TRX test is possible (it does pass the test). I used my old multi-TRX config file that actually worked with UltraSite (and MetroSite) where the second TRX only has TCH/F so nothing fancy, no hopping or anything like that. I wonder if my modification of moving the RSL bootsrap to after CONF_COMPLETE somehow changed something, maybe the BTS requires the RSL LAPD links to be up during the CONF state? Or the new FSM lchan refactoring might have introduced this in 2018... So apparently we have some more basic issues here then hopping :-) Regards, Csaba

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OpenBSC June 2023