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osmo-bts-trx + osmo-trx: dummy burst filling
by Vadim Yanitskiy 01 Aug '20

01 Aug '20

Hi all, as some of you may know, I am currently working on baseband frequency hopping implementation for osmo-bts-trx (see OS#4546). I've already submitted more or less final implementation to Gerrit [1], and in general it works fine [2]. The idea is quite simple: you have several RF carriers (transceivers) with fixed frequencies, so on hopping timeslots osmo-bts-trx distributes bursts between them according to the configured hopping sequence. However, when it comes to hopping timeslots on C0, the burst distribution algorithm gets a bit more complicated. The problem is that on C0 the BTS has to maintain constant power level, even if there is nothing to transmit, so the phones can detect it reliably during the power scan. This is achieved by sending dummy bursts. When frequency hopping is not in use, the scheduler in osmo-bts-trx sends a dummy burst immediately. When it is in use, sending dummy bursts needs to be postponed until all transceivers are processed, because some other transceiver might need to send a normal burst on the frequency of C0, and there would be no need to send a dummy burst in that case. So I came up with [3] (any comments regarding potential optimizations and further improvements are welcome). While working on this, I stumbled upon the burst filling feature in osmo-trx [4], that is disabled by default. If enabled, osmo-trx would be sending dummy bursts itself, so there is no need to send them from osmo-bts-trx, and thus no need to complicate the burst distribution logic. I am now wondering why don't we enable this feature by default? From the VTY reference: > Send a dummy burst when there is nothing to send on C0 (TRX0) and > empty burst on other channels. Use for OpenBTS compatibility only, > don’t use with OsmoBTS as it breaks encryption. it's unclear how sending dummy bursts would break encryption... [1] https://gerrit.osmocom.org/c/osmo-bts/+/19030 [2] https://www.youtube.com/watch?v=tGMVNYo9s7E [3] https://gerrit.osmocom.org/c/osmo-bts/+/19029 [4] http://ftp.osmocom.org/docs/latest/osmotrx-vty-reference.pdf#subsection.1.9… Best regards, Vadim. -- - Vadim Yanitskiy <vyanitskiy 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

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libosmocore / osmo_fd / select() / performance
by Harald Welte 21 Jul '20

21 Jul '20

Hi all, it has been coming up in at least two contexts recently: Select is showing up a lot in system-level profiles particularly on osmo-bts. This is hardly surprising, as select() is not particularly known for efficiency. It was used back in 2008 for the *BSC*, in a context where we were talking about 1-10 BTS with each no more than 1-2 TRX. Now we are using the same osmo_fd abstraction on the BTS, where the number of messages per second is much higher, particularly in osmo-bts-trx with its TRXD protocol, and particularly with higher number of TRX per BTS. There is an older feature request to introduce epoll support in https://osmocom.org/issues/1579 but unfortunately nobody has been finding the resources and/or time to implement it. Meanwhile, 1.5 years ago, the Linux kernel received a new sub-system called io_uring, which I would personally love to support. Here are some pointers for those who are interested: https://lwn.net/Articles/776703/ https://kernel.dk/io_uring.pdf https://lwn.net/Kernel/Index/#io_uring As unfortunately not everyone is using half-way recent kernels, we will likely have to fall back to epoll or something like that. Regards, Harald -- - 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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Osmocom scheduled outage on *2020-07-19 9am CEST*
by Harald Welte 19 Jul '20

19 Jul '20

There is an urgent need to migrate our most important public infrastructure to a new server, and I will be doing that on *Sunday, July 19 2020*, starting about 9am CEST. The migration involves redmine (main osmocom.org website), jenkins, gerrit, git, and cgit. In theory, the migration should be quick. I would expect (significantly) less than one hour of downtime. However, we all know Murphys law. Services not affected are mail (including mailman lists), ftp, dns. So in case of doubt, we can still use mailing lists to communicate. In case anyone urgently needs osmocom source code on Sunday morning during the downtime: There are public mirrors available on github. Regards, Harald -- - 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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OsmoCBC Status?
by Nick Jones 05 Jul '20

05 Jul '20

Hi all, Just wondering what the status of OsmoCBC is? I started compiling from source, but I couldn't find any docs on interfacing with it other than that it's via a HTTP REST API, If there aren't any docs are there packet captures or examples I can work from that'd be quicker than trying to reverse it from the source code, Happy to contribute some docs once I work it out, Cheers, Nick

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Ericsson RBS 6402
by Caleb Pal 01 Jul '20

01 Jul '20

Good Afternoon, I recently acquired a NIB Ericsson RBS 6402. The specific model number appears to be KRD 901 060/83. I see that the osmocom crew has integrated this RBS with NextEPC at the 2019 CCC Camp event. I have used other vendors eNodeB's with NextEPC, and would like to try the RBS with it as well. So far, I have booted up the RBS, and set my machine with a 10.1.1.1/24 IP address. The limited documentation I found online said the RBS should respond to http at 10.1.1.11, at which point an XML site configuration file can be uploaded. I see arp responses in WireShark from 10.1.1.11, but cannot ping, or access http @ 10.1.1.11. If I place the RBS on a network with a DHCP server, it obtains an address, but in the same state, no response to pings, and no http access. Also tried ssh on the standard port, with no response. I see the wiki has information that appears to be output from a terminal. Is that SSH or serial to the board itself? I do have a rasbpi available on the network with a GPS/1PPS source for timing. Is this as simple as setting opt 042 in the DHCP server that the RBS will use? Any guidance is appreciated! v/r, Caleb

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shutdown FSM breaks ttcn3-bsc-test
by Neels Hofmeyr 25 Jun '20

25 Jun '20

dear Pau, please fix either osmo-bts or ttcn3-bsc-tests so that running ttcn3-bsc-tests works again. The failure I get for each and every BSC test: Verdict: fail reason: "Timeout waiting for BTS0 oml-connection-state ""degraded" When I downgrade osmo-bts to 580a27e97c3f0e139dfd7b0c10de24463d4b5294 (just before the shutdown FSM was introduced), the tests work again. (I didn't bisect, just picked that commit.) This failure is particularly harmful now because we're currently struggling with quite a couple of other reasons that cause the ttcn3-bsc-tests to fail. So when we fix those, jenkins won't show the fix, but yet a different error. I'm reluctant to revert your patches now, hopefully you can find a fix quickly to move forward instead. BTW, I also have introduced another new segfault in osmo-bsc myself, testing the fix now and merging it directly when successful, so that we don't all go insane. ~N

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Introducing E1 / Abis support to osmo-mgw
by Harald Welte 20 Jun '20

20 Jun '20

Hi Philipp (and lurkers on this list), I've just pushed an update to the @laforge/trau@ branch of libosmo-abis, which contains the new code modules for E1 / TRAU usage, and also a small test program and test data. The test program takes a raw binary dump created from an E1 timeslot with TRAU frames captured of a BS-11 and converts that to RTP packets. You can feed those RTP packets into osmo-gapk to play them back. The audio is clear, there are just a few seconds of quiet at the beginning before anything is audible. The patches also add an "I460" mode to e1_input. So from the osmo-mgw side, I think we need to * link against libosmo-abis and call e1inp_init + e1inp_vty_init() * use existing VTY code to configure E1 line numbers / drivers / ports * call e1inp_ts_config_i460() on every timeslot we want to use (this should *not* happen on all timeslots, as some of them are used for signalling by the BSC) * call osmo_i460_subchan_add() / osmo_i460_subchan_del() for each i.460 sub-slot we want to use * build the processing chain like in libosmo-abis/contrib/trau2rtp/trau2rtp.c via i460 -> trau_sync -> osmo_trau_frame_decode_16k/osmo_trau_frame_decode_8k -> osmo_trau2rtp I believe this should be at a stage where it can be integrated into osmo-mgw. The API may not be 100% stable yet, but it shouldn't change completely. The main missing bits are: * allow selection of sync pattern in trau_sync.c (or auto-detect?) * handling of T-bits for alignment of air-interface timing with downlink TRAU frame timing I will next be hacking on a small tool that will speak the 'osmo-e1d' protocol but use binary capture files that are looped over and over again. This way you should be able to use libosmo-abis e1_input without any physical card and still get TRAU frame data. At a lower priority, I'd like to look into support for HRv1 and AMR TRAU frames on 16k sub-slots. -- - 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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updated videos / presentations on setting up Osmocom CNI
by Harald Welte 03 Jun '20

03 Jun '20

Hi! I just realized that since OsmoCon was discontinued after 2018 didn't result in sufficient turn-out, and only the 2017 incarnation contained some entry-level talks, we actually only have introductory level presentations / videos about a setup that still covers OsmoNITB. (https://media.ccc.de/v/osmocon17-4002-running_a_basic_circuit_switched_osmo…) This may or may not be a reason why some people still want to set up OsmoNITB in 2020. While our wiki and user manuals all have deprecated OsmoNITB years ago, people who only look for videos might be mislead. Also, I'm sure that several other presentation (like the one about 3G / osmo-iuh before the CNI split) would similarly benefit from an update. So I think we should try to create/update some slide decks and record related lectures / tutorials at some point this year. I wouldn't bother setting up a virtual conference or some kind of remote interaction at this point. Recording some talks and/or screencasts allows us to create and release them one-by-one. I would like to get started by collecting a list of topics at https://osmocom.org/issues/4578 before we start to actually work on the presentations. One question is also how to record, but let's first work on the content before we worry about recording and publication. Regards, Harald -- - 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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ttcn3-bsc-test: LCLS test cases broken since build #987 (May 29)
by Vadim Yanitskiy 03 Jun '20

03 Jun '20

Hi all, as was noticed during the weekly review, all TTCN-3 BSC test cases from LCLS group are failing since build #987 (May 29) [1], so I am trying to investigate this. Until now I thought that it's somehow related to my IPA/RSL refactoring patch set, so I spent half of a day reading the code of those test cases and trying to figure out what could be the reason. But then I checked ttcn3-bsc-test-latest [2]. I should have done this first, of course. Magically all LCLS test cases are green there. So I assume that it's not related to the recent IPA/RSL changes, and most likely caused by recent changes to osmo-bsc and/or libosmo-*. I already tried to downgrade osmo-bsc to v1.6.0 (Jan 3) with no luck. If anyone was working on something related to RSL, MGCP or LCLS, please let me know - this might help to find the problem faster. Thanks! [1] https://jenkins.osmocom.org/jenkins/view/TTCN3/job/ttcn3-bsc-test/ [2] https://jenkins.osmocom.org/jenkins/view/TTCN3/job/ttcn3-bsc-test-latest/ -- - Vadim Yanitskiy <vyanitskiy 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

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Osmo-SIP-Connector Version 6
by Sonny Lafuente 30 May '20

30 May '20

Hi Community, Does anyone here tried to upgrade the your working OSMO environment to its latest version? I have the experience where I upgraded my working osmo to the latest version and I have encountering some problem between the connection of osmo-nitb and osmo-sip-connector. For the latest sip connector update it will communicate the connection going to osmo-msc. Since I don’t use the osmo-msc instead I am using the osmo-nitb for the standalone project. Below is the error I have experiencing right now in the osmo-sip-connector and osmo-nitb. SIP Connector Logs: <0001> mncc.c:845 Incompatible version(5) expected 6 <0001> mncc.c:936 Reconnected to /tmp/msc_mncc <0001> mncc.c:841 Got hello message version 5 <0001> mncc.c:845 Incompatible version(5) expected 6 <0001> mncc.c:936 Reconnected to /tmp/msc_mncc <0001> mncc.c:841 Got hello message version 5 <0001> mncc.c:845 Incompatible version(5) expected 6 OSMO-NITB Logs: Fri May 29 13:13:16 2020 <0006> mncc_sock.c:84 MNCC Socket has LOST connection Fri May 29 13:13:16 2020 <0001> gsm_04_08.c:463 Clearing all currently active transactions!!! Fri May 29 13:13:21 2020 <0006> mncc_sock.c:271 MNCC Socket has connection with external call control application Fri May 29 13:13:21 2020 <0006> mncc_sock.c:84 MNCC Socket has LOST connection Fri May 29 13:13:21 2020 <0001> gsm_04_08.c:463 Clearing all currently active transactions!!! Here are the configuration file of osmo-nitb and osmo-sip-connector and how we run the command. SIP Connector: Command to run: ./osmo-sip-connector -c ~/osmo-sip-connector.cfg Config File: # sip local 192.168.1.166 5062 remote 192.168.1.166 5060 sofia-sip log-level 2 mncc socket-path /tmp/msc_mncc app OSMO NITB: Command to run: ./osmo-nitb -C -c ~/osmo-nitb.cfg -T -P -l /home/hlr.sqlite3 -M /tmp/msc_mncc Config File: line vty no login ! e1_input e1_line 0 driver ipa e1_line 0 port 0 no e1_line 0 keepalive network network country code 94 mobile network code 1 short name 1 long name 1 auth policy accept-all authorized-regexp .* location updating reject cause 13 encryption a5 0 neci 1 paging any use tch 0 rrlp mode none mm info 1 handover 0 handover window rxlev averaging 10 handover window rxqual averaging 1 handover window rxlev neighbor averaging 10 handover power budget interval 6 handover power budget hysteresis 3 handover maximum distance 9999 timer t3109 1 timer t3105 1 timer t3113 60 timer t3103 1 timer t3122 10 timer t3101 10 dyn_ts_allow_tch_f 0 subscriber-keep-in-ram 1 bts 0 type sysmobts band GSM900 cell_identity 1 location_area_code 1 base_station_id_code 63 ms max power 0 cell reselection hysteresis 4 rxlev access min 0 periodic location update 30 radio-link-timeout 32 channel allocator descending rach tx integer 9 rach max transmission 7 channel-descrption attach 1 channel-descrption bs-pa-mfrms 5 channel-descrption bs-ag-blks-res 1 early-classmark-sending forbidden ip.access unit_id 1000 0 oml ip.access stream_id 255 line 0 neighbor-list mode automatic codec-support fr hr efr amr amr tch-h modes 0 amr tch-h start-mode auto gprs mode gprs gprs 11bit_rach_support_for_egprs 0 gprs routing area 1 gprs network-control-order nc0 gprs cell bvci 2 gprs cell timer blocking-timer 3 gprs cell timer blocking-retries 3 gprs cell timer unblocking-retries 3 gprs cell timer reset-timer 3 gprs cell timer reset-retries 3 gprs cell timer suspend-timer 10 gprs cell timer suspend-retries 3 gprs cell timer resume-timer 10 gprs cell timer resume-retries 3 gprs cell timer capability-update-timer 10 gprs cell timer capability-update-retries 3 gprs nsei 101 gprs ns timer tns-block 3 gprs ns timer tns-block-retries 3 gprs ns timer tns-reset 3 gprs ns timer tns-reset-retries 3 gprs ns timer tns-test 30 gprs ns timer tns-alive 3 gprs ns timer tns-alive-retries 10 gprs nsvc 0 nsvci 101 gprs nsvc 0 local udp port 23000 gprs nsvc 0 remote udp port 23000 gprs nsvc 0 remote ip 127.0.0.2 gprs nsvc 1 nsvci 0 gprs nsvc 1 local udp port 0 gprs nsvc 1 remote udp port 0 gprs nsvc 1 remote ip 0.0.0.0 no force-combined-si trx 0 rf_locked 0 arfcn 74 nominal power 0 rsl e1 tei 0 timeslot 0 phys_chan_config CCCH+SDCCH4 hopping enabled 0 timeslot 1 phys_chan_config TCH/F hopping enabled 0 timeslot 2 phys_chan_config TCH/F hopping enabled 0 timeslot 3 phys_chan_config TCH/F hopping enabled 0 timeslot 4 phys_chan_config TCH/F hopping enabled 0 timeslot 5 phys_chan_config TCH/F hopping enabled 0 timeslot 6 phys_chan_config TCH/F hopping enabled 0 timeslot 7 phys_chan_config TCH/F hopping enabled 0 trx 1 rf_locked 0 arfcn 65 nominal power 0 rsl e1 tei 0 timeslot 0 phys_chan_config CCCH+SDCCH4 hopping enabled 0 timeslot 1 phys_chan_config TCH/F hopping enabled 0 timeslot 2 phys_chan_config TCH/F hopping enabled 0 timeslot 3 phys_chan_config TCH/F hopping enabled 0 timeslot 4 phys_chan_config TCH/F hopping enabled 0 timeslot 5 phys_chan_config TCH/F hopping enabled 0 timeslot 6 phys_chan_config TCH/F hopping enabled 0 timeslot 7 phys_chan_config TCH/F hopping enabled 0 mncc-int default-codec tch-f fr default-codec tch-h amr nitb subscriber-create-on-demand subscriber-create-on-demand random 100000 199999 no assign-tmsi smpp local-tcp-ip 127.0.0.1 2776 system-id password policy closed smpp-first esme root password password default-route Thank you. Sonny

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