OpenBSC July 2015

openbsc@lists.osmocom.org

14 participants
20 discussions

GPRS - local and foreign TLLIs
by Luca Melette 04 Feb '26

04 Feb '26

Hello everybody, after setting up a nanoBTS with OpenBSC/SGSN/GGSN, I had some troubles trying to connect my smartphone to the GPRS cell. Investigating the BTS-to-SGSN traffic, I saw that the frames sent by the SGSN were all marked with the same N(U) value (at LLC layer), the value was 0. With some debug, I found that the there was a mismatch in the TLLI storage, used to keep the status of attached terminals. The mentioned code is contained in gprs_llc.c, involving LL Entity functions and gprs_llc_tx_ui(). /* look-up or create the LL Entity for this (TLLI, SAPI) tuple */ lle = lle_by_tlli_sapi(msgb_tlli(msg), sapi); if (!lle) { struct gprs_llc_llme *llme; LOGP(DLLC, LOGL_ERROR, "LLC TX: unknown TLLI 0x%08x, " "creating LLME on the fly\n", msgb_tlli(msg)); llme = llme_alloc(msgb_tlli(msg)); lle = &llme->lle[sapi]; } The TX function uses the previously received TLLI to lookup for the LLE. The lle_by_tlli_sapi() performs the search, but preliminary it applies a foreign2local TLLI conversion to ensure to have a local one. Since no valid entry for the searched TLLI is found, a new one is created. And the problem is here. The new entry has the foreign TLLI. Next time the lookup fails again, and a new entry is created. This way, the counter N(U) is always reset, and the mobile do not recognize the message sequence and no attach is possible. My question is about foreign and local TLLIs. I patched the lookup, avoiding the conversion, so that the LLE is found and everything works fine... but... What is the sense of the conversion? Should the TLLI be always stored as a local one? Can this problem be solved with another foreign2local while allocating new entries? Actually, my problem has been solved with that workaround. But I'm curious to know what is the right way. Hope somebody can answer :) Thanks. Cheers, LM

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Pysim error: SW match failed
by Martin Nagy 16 Aug '25

16 Aug '25

Hi all, After buying a super Sim Kit (16 in 1) from China, I tried the reader (green PCB inside a blue transparent plastic case with a blue LED) and SIM (identified as a fakesupersim) with pysim tool. However i am getting the following error: /pySim-prog.py -n 26C3 -c 49 -x 262 -y 42 -z 1234 -j 1 -t auto Insert card now (or CTRL-C to cancel) Autodetected card type fakemagicsim Generated card parameters : > Name : 26C3 > SMSP : e1ffffffffffffffffffffffff058100945555ffffffffffff000000 > ICCID : 8949262427518313026 > MCC/MNC : 262/42 > IMSI : 262422461512085 > Ki : 7b74741a1ee14337ec23f9ab92a13648 > OPC : ccd867d60797d8d45354a51b3ef568ff Programming ... Traceback (most recent call last): File "./pySim-prog.py", line 530, in <module> card.program(cp) File "/home/nadicek/pysim/pysim/pySim/cards.py", line 231, in program self._scc.update_binary('6f30', hplmn + 'ff' * (tl-3)) File "/home/nadicek/pysim/pysim/pySim/commands.py", line 53, in update_binary return self._tp.send_apdu_checksw(pdu) File "/home/nadicek/pysim/pysim/pySim/transport/__init__.py", line 87, in send_apdu_checksw raise RuntimeError("SW match failed ! Expected %s and got %s." % (sw.lower(), rv[1])) RuntimeError: SW match failed ! Expected 9000 and got 9804. I checked mailing lists and haven’t found anybody who had similar problem with pysim. Also I have tried forcing different models of SIM, but nothing is working. Obviously I can remove this check from the script file (__init__.py in /pySim/transport), however somebody had a reason to put such condition there. I would like to ask if it is safe to remove that line of code and the purpose of that line of code. Thanks a lot and best regards Martin

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Re: Help with sccp library
by mosbah abdelkader 08 Jul '25

08 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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[PATCH 0/4] core/conv: Fast Viterbi decoding
by Thomas Tsou 27 Apr '16

27 Apr '16

Hi all, This patch set adds to libosmocore an optimized Viterbi decodeer for architecture specific (Intel SSE) and non-specific cases. The implementation covers codes with constraint lengths of K=5 and K=7 and rates 1/4 to 3/4, which make up the majority of GSM use cases. Speedup from the current implementation is in the range of 5 to 20 depending on the processor and code type. API is unchanged. Tested on Haswell (i7-4770K) and Atom (D2550). Additional test codes from osmo-bts are included. Further tests for AWGN bit-error-rate and benchmarks can be found in the following repository. https://github.com/ttsou/osmo-conv-test Here are some examples. Bit error test for GPRS CS2 with SNR of 5 dB and 100000 bursts. $ ./conv_test -c 2 -e -r 5 -i 100000 ================================================= [+] Testing: GPRS CS2 [.] Specs: (N=2, K=5, non-recursive, flushed, not punctured) [.] Input length : ret = 290 exp = 290 -> OK [.] Output length : ret = 588 exp = 588 -> OK [.] BER tests: [..] Testing base: [..] Input BER.......................... 0.042443 [..] Output BER......................... 0.000006 [..] Output FER......................... 0.001350 (135) [..] Testing SIMD: [..] Input BER.......................... 0.042460 [..] Output BER......................... 0.000005 [..] Output FER......................... 0.001240 (124) Timed AFS benchmark with 8 threads and 100000 bursts per thread. $ ./conv_test -b -c 10 -j 8 -i 100000 ================================================= [+] Testing: GSM TCH/AFS 6.7 [.] Specs: (N=4, K=5, recursive, flushed, punctured) [.] Input length : ret = 140 exp = 140 -> OK [.] Output length : ret = 448 exp = 448 -> OK [.] Performance benchmark: [..] Encoding / Decoding 800000 bursts on 8 thread(s): [..] Testing base: [..] Elapsed time....................... 4.320001 secs [..] Rate............................... 25.925920 Mbps [..] Testing SIMD: [..] Elapsed time....................... 0.458272 secs [..] Rate............................... 244.396341 Mbps [..] Speedup............................ 9.426718 -TT

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[PATCH libosmo-netif 00/18] add dummy padding support
by pablo＠gnumonks.org 19 Aug '15

19 Aug '15

From: Pablo Neira Ayuso <pablo(a)netfilter.org> The following patchset, although it looks a bit large, it is composed of many small incremental changes to improve the existing osmux infrastructure and to add dummy padding support. The dummy padding consists of a osmux header and payload that looks like this: OSMUX seq=000 ccid=002 ft=2 ctr=3 amr_f=0 amr_q=0 amr_ft=03 amr_cmr=00 ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ] The frame type is OSMUX_FT_DUMMY (=2) in the batch that whose payload is padded with 0xff. Note that the message above is padding the circuit ID 2. This is used for early bandwidth preallocation in links that involve relatively slow dynamic bandwidth allocation such as Iridium/OpenPort. The osmux test infrastructure has been improved (to resolve some memleaks) and enhanced to cover this new dummy support. The OpenBSC changeset is composed of one very small patch that will come after this batch. If no major concerns, I'll push this initial batch soon into the repository. Thanks. Pablo Neira Ayuso (18): osmux: discard non voice osmux message osmux: add osmux_input_state structure osmux: add circuit helper functions osmux: rename struct batch_list_node to osmux_circuit osmux: rename circuit->list to circuit->rtp_list osmux: pass up struct osmux_batch osmux: count pending messages to be transformed in the batch osmux: introduce osmux_xfrm_input_close_circuit() osmux: introduce osmux_xfrm_input_open_circuit() tests: osmux: adapt it to use the new circuit API tests: osmux: factor out main test loop tests: osmux: test online deactivation of dummy padding tests: osmux: validate dummy padding with no voice data interaction tests: osmux: test circuit reopening after closure osmux: kill osmux_get_hdr() tests: osmux: fix msgb leaks tests: compile tests with debugging symbols, ie. -g tests: osmux: iterate 64 times in osmo_test_loop() include/osmocom/netif/osmux.h | 8 +- src/osmux.c | 374 ++++++++++++++++++++++++++--------------- tests/Makefile.am | 2 +- tests/osmux/osmux_test.c | 80 ++++++--- 4 files changed, 304 insertions(+), 160 deletions(-) -- 1.7.10.4

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Using GPRS
by OMAR RAMADAN 13 Aug '15

13 Aug '15

Hi list, I've installed omsocom for the first time on a USRP B200 and I'm interested in trying out the GPRS stack. I've followed a few pages on the wiki, namely http://openbsc.osmocom.org/trac/wiki/network_from_scratch and http://openbsc.osmocom.org/trac/wiki/OpenBSC_GPRS to get set up and I am not sure how up to date these tutorials are. I have calls working via the LCR, but I cannot get GPRS functioning. I see no activity on the BSC log when attempting GPRS attach using APN openbsc. I also see no traffic between the SGSN and the BSC (listening with tshark on 127.0.0.1:23000). Any help is appreciated. I am currently using osmo-trx/master, osmo-bsc/jolly/testing, libosmo-abis/jolly/multi-trx, omso-bts/jolly/trx, openggsn/master, and osmo-pcu/master. Best, Omar

8 21

MNCC and LCR
by ☎ 11 Aug '15

11 Aug '15

Hi all. One of the options for call routing for OpenBSC is LCR. They talk to each other over MNCC which is nice versioned protocol. What puzzles me most is the version difference: OpenBSC: openbsc/include/openbsc/mncc.h:166:#define MNCC_SOCK_VERSION 4 LCR: mncc.h:333:#define MNCC_SOCK_VERSION 5 The OpenBSC is latest from git://git.osmocom.org/openbsc master branch, the LCR is latest from git://git.misdn.eu/lcr.git, master branch as well. So, what am I missing? Where does this version difference comes from? On a related note - the MNCC code in OpenBSC is part of libbsc but there's no such package or library when I'm building .deb for example. If we could split off MNCC implementation into separate library (libmncc? libosmocore?) and use it from both LCR, OpenBSC (and whatever else we might want to use in future) than it would solve such versioning and compatibility issues once and for all. What do you think? -- best regards, Max, http://fairwaves.co

3 4

[PATCH 1/2] nitb: Be less strict about the reject cause
by Holger Hans Peter Freyther 06 Aug '15

06 Aug '15

From: Holger Hans Peter Freyther <holger(a)moiji-mobile.com> When we can't find the TMSI then the subscriber is not in our VLR. We have not consulted with the HLR and it is better to not use such a severe error code. --- openbsc/src/libmsc/gsm_04_08.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/openbsc/src/libmsc/gsm_04_08.c b/openbsc/src/libmsc/gsm_04_08.c index 29ab2ba..e380d94 100644 --- a/openbsc/src/libmsc/gsm_04_08.c +++ b/openbsc/src/libmsc/gsm_04_08.c @@ -968,7 +968,7 @@ static int gsm48_rx_mm_serv_req(struct gsm_subscriber_connection *conn, struct m /* FIXME: if we don't know the TMSI, inquire abit IMSI and allocate new TMSI */ if (!subscr) return gsm48_tx_mm_serv_rej(conn, - GSM48_REJECT_IMSI_UNKNOWN_IN_HLR); + GSM48_REJECT_IMSI_UNKNOWN_IN_VLR); if (!conn->subscr) conn->subscr = subscr; -- 2.3.5

3 5

OpenBSC + Huawei BTS 3900B
by Роман Жогов 04 Aug '15

04 Aug '15

Hi all. I'm working on probation on mobile operator as a student. Currently, I'm trying to create site for testing, using Huawei BTS 3900B and OpenBSC software. But I can't set up it. I have a several questions: 1) Huawei BTS uses Abis over IP, how can I connect this BTS to OpenBSC. 2) Are there any examples of configuration in this case? Thanks.

2 1

osmo-nitb hangs with large hlr.sqlite3 file
by F Abdu 04 Aug '15

04 Aug '15

Dear Experts, Hello, I am running a gsm system with followings: OpenBSC version: 0.13.0.319-30e0e LCR version 1.14 astersik version 1.8.10.1 The system is sited is a busy area. The system works fine for few days but hangs once the hlr.sqlite3 file size reaches near 12 MB and that causes the osmo-nitb to take 99% of the cpu usage. I used "./osmo-nitb -m -P -C" to run the system. The hlr.sqlite3 file increases @2MB/Day. The 'Subscriber' table of the hlr.sqlite3 file adds a large number of IMSI with authorized=0. Tables like Counters, Eqipment and EquipmentWatch are filling up with lots of data. Now the only solution to this problem is to manually delete the data from the tables. May I get some light to solve the issue form the experts like you all? With regards. [ Content from the openbsc.cfg file is as following: ! ! OpenBSC configuration saved from vty ! ! password foo ! line vty no login ! e1_input e1_line 0 driver ipa network network country code XXX mobile network code XX short name Test long name Test auth policy closed location updating reject cause 13 encryption a5 0 neci 1 rrlp mode none mm info 0 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 t3101 10 timer t3103 0 timer t3105 0 timer t3107 0 timer t3109 4 timer t3111 1 timer t3113 60 timer t3115 0 timer t3117 0 timer t3119 0 timer t3141 0 bts 0 type sysmobts band GSMXXX cell_identity X location_area_code X training_sequence_code 7 base_station_id_code 63 ms max power 30 cell reselection hysteresis 4 rxlev access min 0 periodic location update 100 channel allocator ascending rach tx integer 9 rach max transmission 7 ip.access unit_id XXXX 0 oml ip.access stream_id 255 line 0 gprs mode none trx 0 rf_locked 0 arfcn XXX nominal power 23 max_power_red XX rsl e1 tei 0 timeslot 0 phys_chan_config CCCH+SDCCH4 timeslot 1 phys_chan_config SDCCH8 timeslot 2 phys_chan_config TCH/F timeslot 3 phys_chan_config TCH/F timeslot 4 phys_chan_config TCH/F timeslot 5 phys_chan_config TCH/F timeslot 6 phys_chan_config TCH/F timeslot 7 phys_chan_config TCH/F

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