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4217 discussions

SDP API choices
by Neels Hofmeyr 26 Feb '24

26 Feb '24

Hi all, I'm currently working on 2G to 3G TrFO voice negotiation. In practice, that means, to be able to negotiate a set of AMR rates via SDP. And that, in turn, means that we handle fmtp properly in SDP strings. SDP is not only used in SIP to the other call leg, but also in the MGCP to the media gateway. - So we have a bunch of SDP and fmtp related code in osmo-mgw.git. - Separately, we have an SDP implementation in osmo-msc.git, because the SDP code in osmo-mgw.git was too tightly coupled with other code to be able to reuse it for MNCC->SIP. For fmtp negotiation, I now want similar things in both mgw and msc. What I want to do now, is move the SDP implementation from osmo-msc.git to osmo-mgw.git/libosmo-mgcp-client and make it public API: a common place that will also enable all other MGCP clients to work with AMR fmtp. All of this was just the intro =) the question I would like to put out there is about API design: static or dynamic, and opaque or transparent. Am I overthinking this? Or would you like to overthink it with me? == static or dynamic == In osmo-msc.git, the SDP structs so far are fully static and self-contained. The cool thing is that they can be copied around quite easily and there is no need for passing talloc ctx pointers, no need to worry about ownership, memleaks and double frees. But it also means that it uses fixed sizes: - char encoding_name[16], - char fmtp[256], - struct sdp_audio_codec codecs[32] and so on. Unfortunately, RFC-8866 does not define any limits whatsoever on number of characters or number of codecs in an SDP message. Quoting: "although no length limit is given, it is recommended that they be short" Thanks for nothing! >:( So for static API design, we need to now pick a good size for every single item in advance. When fmtp has max 256 bytes and codec lists have max 32 entries, even an empty list will use 32 * 256+ bytes: lots of heap allocations. And the limits are hard: anyone wanting to correctly express more than 32 different codec variants can simply not use this library. Dynamic seems a much better fit for RFC-8866. There is practically no limit at all on string length / list length. Also the caller allocates not one byte more memory than is actually needed. The argument has been going back and forth in my head for weeks. Static makes things so much simpler. But what sizes should we dictate. Ok then dynamic. But these days we have "infinite" memory, the bottleneck is CPU time, so if we can be static, we are gracious on very cheap real estate (memory) while saving a lot of the precious stuff (cycles). Ok then static. But with all those AMR variants that are coming up, I want to at least be able to represent all of them in one list, so I need at least 64 entries. And let's allow long fmtp strings, who knows. Then we'll end up with ~20kb of data that every codec list out there will use up, even if it is empty. Even if it is just a temporary local variable. Even if it is just dragged along for a rare use case and never actually needed. Is it really faster to allocate 100 times more memory statically versus allocating just enough but dynamically? In the end I decided for dynamic allocation. When I started adding talloc ctx args, I wanted the API to be simple, so every single part of the puzzle is now its own dynamic allocation: struct osmo_sdp_msg { char *username; // talloc_strdup() char *session_name; // talloc_strdup() [...] struct osmo_sdp_codec_list *codecs; // osmo_sdp_codec_list_alloc() // llist_head // -> osmo_sdp_codec_alloc() // \___ char *encoding_name -> talloc_strdup() // _ char *fmtp -> talloc_strdup() // -next-> osmo_sdp_codec_alloc() // \___ ... // -next-> osmo_sdp_codec_alloc() // \___ ... }; All of this used to be just a single self-contained struct. You might ask, why is 'codecs', which is just the llist_head, a separate allocation? Because I want the API to trivially figure out the talloc parent context to allocate items from: osmo_codec_list_add(my_list, my_codec); and not have to worry about the individual code paths' parent context to allocate new entries from: osmo_codec_list_add(&my_obj->my_list, my_obj->backpointer.backpointer.ctx, my_codec); So the only functions with a talloc ctx argument are osmo_codec_alloc(ctx) and osmo_codec_list_alloc(ctx) This style has a tendency to spread: Now I want to also make osmo-msc's struct codec_filter a dynamic allocation, because the codec_filter_foo() currently have no ctx argument; they still use the static SDP structs. When the codec_filter pointer itself is the neat logical talloc parent of the codec lists it uses, then I don't need to add a separate ctx arg everywhere now. Am I taking this too far now? Am I overthinking it and either way is fine? == opaque vs transparent == I can either have the full struct definition in the .h file = transparent, or I can hide the struct in the .c file and provide lots of getter and setter functions = opaque. Both ways have a major advantage over the other: - opaque means that we can freely extend the API without any ABI breakage, ever. - transparent means that callers can easily define const arrays of data structures. In my case, I want to keep const lists of const codecs for e.g. test data in unit tests, for listing known codecs in codec_mapping.c, for defining default codec configuration. transparent allows: const struct osmo_sdp_codec ran_defaults = { { .encoding_name = "AMR", .rate = 8000, .fmtp = "octet-align=1;mode-set=0,2,4,7", .payload_type = 112, }, { .encoding_name = "AMR", .rate = 8000, .fmtp = "octet-align=1;mode-set=0,2,4", .payload_type = 112, }, { .encoding_name = "AMR", .rate = 8000, .fmtp = "mode-set=0,2,4,7", .payload_type = 112, }, { .encoding_name = "AMR", .rate = 8000, .fmtp = "mode-set=0,2,4", .payload_type = 112, }, { .encoding_name = "GSM-EFR", .rate = 8000, .payload_type = 110, }, { .encoding_name = "GSM", .rate = 8000, .payload_type = 3, }, { .encoding_name = "GSM-HR-08", .rate = 8000, .payload_type = 111, }, }; int i; for (i = 0; i < ARRAY_SIZE(ran_defaults); i++) osmo_sdp_codec_list_add(g_ran_codecs_cfg, &defaults[i]) printf("%s", codec->encoding_name); if (!strcmp(codec->encoding_name, "AMR")) printf(":%s", codec->fmtp); same in opaque: osmo_sdp_codec_list_add(g_ran_codecs_cfg, "AMR", 8000, "octet-align=1;mode-set=0,2,4,7", 112); osmo_sdp_codec_list_add(g_ran_codecs_cfg, "AMR", 8000, "octet-align=1;mode-set=0,2,4", 112); osmo_sdp_codec_list_add(g_ran_codecs_cfg, "AMR", 8000, "mode-set=0,2,4,7", 112); osmo_sdp_codec_list_add(g_ran_codecs_cfg, "AMR", 8000, "mode-set=0,2,4", 112); osmo_sdp_codec_list_add(g_ran_codecs_cfg, "GSM-EFR", 8000, NULL, 110); osmo_sdp_codec_list_add(g_ran_codecs_cfg, "GSM", 8000, NULL, 3); osmo_sdp_codec_list_add(g_ran_codecs_cfg, "GSM-HR-08", 8000, NULL, 111); printf("%s", osmo_sdp_codec_get_encoding_name(codec)); if (!strcmp(osmo_sdp_codec_get_encoding_name(codec), "AMR")) printf(":%s", osmo_sdp_codec_get_ftmp(codec)); The opaque looks alright in comparison, but - being able to enlist a struct osmo_sdp_codec in a const array is powerful, allowing the paradigm to replace code complexity by good data structures. So used in codec_mapping.c in osmo-msc. - requiring getters and setters for each end every member creates a long list of API functions: 'get' and 'set' for each orthogonal member; we might be tempted to "dupe" many llist_*() functions for osmo_sdp_codec_list. - having to call functions for each end every member makes the code a lot more noisy. - it forces all allocation decisions down onto the caller = only using the API author's favorite dynamic allocation, hello memleaks etc. IMHO, opaque APIs are often lots of code with very low density of actually important stuff. /* This function gets foo. */ struct foo *get_foo(x) { return x->foo; } This is so plump and boring!! Currently I am following the transparent way, and putting 'bool v2;' extension flags for a distant future in the structs' ends. But there has been a discussion here that the truly good APIs are opaque. talloc, libSDL, libsndfile come to mind. == both == Finally, these two aspects are interdependent: An opaque API *has* to be dynamic. So far, I am moving from the transparent+static implementation to transparent+dynamic. Should I also go the "next" step to opaque+dynamic? I don't really want to... I've had these considerations many times in my life, and there never seems to be the one best way. Thanks for your thoughts! If you need more code reference for what I am talking about: old static: https://cgit.osmocom.org/osmo-msc/tree/include/osmocom/msc/sdp_msg.h?id=1b1… https://cgit.osmocom.org/osmo-msc/tree/src/libmsc/sdp_msg.c?id=1b1a39bea1c5… new dynamic+transparent: https://cgit.osmocom.org/osmo-mgw/tree/include/osmocom/sdp?h=neels/sdp&id=2… https://cgit.osmocom.org/osmo-mgw/tree/src/libosmo-sdp?h=neels/sdp&id=24c09… ~N -- - Neels Hofmeyr <nhofmeyr(a)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 * Geschäftsführer / Managing Directors: Harald Welte

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ERROR Trying to dispatch event 17 to non-existent FSM instance!
by JPichel 08 Feb '24

08 Feb '24

Hi, I hope this is the place to ask this, if not I will delete this post. I am trying to run my own 2G network for researching purposes. I am running the following elements: - osmo-bts-trx (connecting to osmo-trx-uhd driving a USRP B205mini-i) - osmo-bsc - osmo-msc - osmo-hlr - osmo-mgw I built all the programs from source on Ubuntu 22.04. Everything is running locally on one machine. Everything seems to be running OK. I was able to register two different subscribers by IMSI (without providing K and OPc) and assign MSISDN tothem. They can use the default USSD codes for seeing their IMSI and their MSISDN and I can make voice calls between both subscribers. I am mostly using the default config files provided with the installation, the only changes I made to them was to point IPs to 127.0.0.1 to run everything on the same machine. But when starting osmo-bsc and osmo-msc I get the same error on both: jonathan@em680:~/tfg/osmo/config$ osmo-msc -c osmo-msc.cfg DLGLOBAL NOTICE Available via telnet 127.0.0.1 4254 (telnet_interface.c:88) DLCTRL NOTICE CTRL at 127.0.0.1 4255 (control_if.c:1014) DLGSUP NOTICE GSUP connecting to 127.0.0.1:4222 (gsup_client.c:74) DDB NOTICE Init database connection to 'sms.db' using SQLite3 lib version 3.37.2 (db.c:521) DLMGCP NOTICE MGW(mgw) MGCP client: using endpoint domain '@mgw' (mgcp_client.c:933) DMSC NOTICE MGW pool with 1 pool members configured, (ignoring MGW configuration in VTY node 'msc'). (msc_main.c:596) DLSCCP NOTICE OsmoMSC-A: Creating SS7 instance (sccp_user.c:536) DLSCCP NOTICE OsmoMSC-A: Using SS7 instance 0, pc:0.23.1 (sccp_user.c:563) DLSCCP NOTICE OsmoMSC-A: Creating AS instance (sccp_user.c:570) DLSCCP NOTICE OsmoMSC-A: Using AS instance as-clnt-OsmoMSC-A (sccp_user.c:581) DLSCCP NOTICE OsmoMSC-A: Creating default route (sccp_user.c:587) DLSCCP NOTICE OsmoMSC-A: No unassociated ASP for m3ua, creating new ASP asp-clnt-OsmoMSC-A (sccp_user.c:626) DLGLOBAL ERROR Trying to dispatch event 17 to non-existent FSM instance! (osmo_ss7_as.c:118) DLGLOBAL ERROR backtrace() returned 11 addresses (backtrace.c:42) DLGLOBAL ERROR /usr/local/lib/libosmocore.so.21(osmo_log_backtrace+0x24) [0x7fc1ddd9fdcc] (backtrace.c:53) DLGLOBAL ERROR /usr/local/lib/libosmocore.so.21(_osmo_fsm_inst_dispatch+0x144) [0x7fc1dddaade7] (backtrace.c:53) DLGLOBAL ERROR /usr/local/lib/libosmo-sigtran.so.9(osmo_ss7_as_add_asp+0x1f9) [0x7fc1ddcfb80c] (backtrace.c:53) DLGLOBAL ERROR /usr/local/lib/libosmo-sigtran.so.9(osmo_sccp_simple_client_on_ss7_id+0xa48) [0x7fc1ddd1dd5e] (backtrace.c:53) DLGLOBAL ERROR osmo-msc(+0x26fd8) [0x55fa5388bfd8] (backtrace.c:53) DLGLOBAL ERROR osmo-msc(+0x27043) [0x55fa5388c043] (backtrace.c:53) DLGLOBAL ERROR osmo-msc(+0x27bed) [0x55fa5388cbed] (backtrace.c:53) DLGLOBAL ERROR /lib/x86_64-linux-gnu/libc.so.6(+0x29d90) [0x7fc1dd95fd90] (backtrace.c:53) DLGLOBAL ERROR /lib/x86_64-linux-gnu/libc.so.6(__libc_start_main+0x80) [0x7fc1dd95fe40] (backtrace.c:53) DLGLOBAL ERROR osmo-msc(+0x26565) [0x55fa5388b565] (backtrace.c:53) DLSCCP NOTICE OsmoMSC-A: Using ASP instance asp-clnt-OsmoMSC-A (sccp_user.c:695) DLSS7 NOTICE 0: Creating SCCP instance (osmo_ss7.c:408) DSGS NOTICE SGs socket bound to r=NULL<->l=0.0.0.0:29118 (sgs_server.c:186) DMSC NOTICE A-interface: SCCP user OsmoMSC-A:RI=SSN_PC,PC=(no PC),SSN=BSSAP, cs7-instance 0 ((null)) (msc_main.c:806) DLINP NOTICE 127.0.0.1:4222 connection done (ipa.c:141) DLINP NOTICE received ID_GET for unit ID 0/0/0 (ipaccess.c:919) DLM3UA NOTICE 0: asp-asp-clnt-OsmoMSC-A: Received NOTIFY Type State Change:AS Inactive () (m3ua.c:625) DLSS7 NOTICE xua_default_lm(asp-clnt-OsmoMSC-A)[0x55fa542bb080]{ACTIVE}: Ignoring primitive M-ASP_ACTIVE.confirm (xua_default_lm_fsm.c:400) DLM3UA NOTICE 0: asp-asp-clnt-OsmoMSC-A: Received NOTIFY Type State Change:AS Active () (m3ua.c:625) DLM3UA NOTICE 0: asp-asp-clnt-OsmoMSC-A: Rx DAVA() for 0.23.3/0, (xua_snm.c:403) ... jonathan@em680:~/tfg/osmo/config$ osmo-bsc -c osmo-bsc.cfg DLGLOBAL NOTICE Available via telnet 127.0.0.1 4242 (telnet_interface.c:88) DLINP NOTICE enabling ipaccess BSC mode on 0.0.0.0 with OML 3002 and RSL 3003 TCP ports (ipaccess.c:1055) DLCTRL NOTICE CTRL at 127.0.0.1 4249 (control_if.c:1014) DLMGCP NOTICE MGW(mgw) MGCP client: using endpoint domain '@mgw' (mgcp_client.c:933) DNM NOTICE MGW pool with 1 pool members configured, (ignoring MGW configuration in VTY node 'msc'). (osmo_bsc_main.c:889) DMSC NOTICE To auto-configure msc 0, creating cs7 instance 0 implicitly (osmo_bsc_sigtran.c:600) DMSC NOTICE Initializing SCCP connection for A/m3ua on cs7 instance 0 (osmo_bsc_sigtran.c:647) DLSCCP ERROR SS7 instance 0: no primary point-code set, using default point-code (sccp_user.c:557) DLSCCP NOTICE A-0-m3ua: Using SS7 instance 0, pc:0.23.3 (sccp_user.c:563) DLSCCP NOTICE A-0-m3ua: Creating AS instance (sccp_user.c:570) DLSCCP NOTICE A-0-m3ua: Using AS instance as-clnt-A-0-m3ua (sccp_user.c:581) DLSCCP NOTICE A-0-m3ua: Creating default route (sccp_user.c:587) DLSCCP NOTICE A-0-m3ua: No unassociated ASP for m3ua, creating new ASP asp-clnt-A-0-m3ua (sccp_user.c:626) DLGLOBAL ERROR Trying to dispatch event 17 to non-existent FSM instance! (osmo_ss7_as.c:118) DLGLOBAL ERROR backtrace() returned 10 addresses (backtrace.c:42) DLGLOBAL ERROR /usr/local/lib/libosmocore.so.21(osmo_log_backtrace+0x24) [0x7f990ff0ddcc] (backtrace.c:53) DLGLOBAL ERROR /usr/local/lib/libosmocore.so.21(_osmo_fsm_inst_dispatch+0x144) [0x7f990ff18de7] (backtrace.c:53) DLGLOBAL ERROR /usr/local/lib/libosmo-sigtran.so.9(osmo_ss7_as_add_asp+0x1f9) [0x7f990fe9380c] (backtrace.c:53) DLGLOBAL ERROR /usr/local/lib/libosmo-sigtran.so.9(osmo_sccp_simple_client_on_ss7_id+0xa48) [0x7f990feb5d5e] (backtrace.c:53) DLGLOBAL ERROR osmo-bsc(+0x144035) [0x556b310d7035] (backtrace.c:53) DLGLOBAL ERROR osmo-bsc(+0x2aef0) [0x556b30fbdef0] (backtrace.c:53) DLGLOBAL ERROR /lib/x86_64-linux-gnu/libc.so.6(+0x29d90) [0x7f990fc55d90] (backtrace.c:53) DLGLOBAL ERROR /lib/x86_64-linux-gnu/libc.so.6(__libc_start_main+0x80) [0x7f990fc55e40] (backtrace.c:53) DLGLOBAL ERROR osmo-bsc(+0x28265) [0x556b30fbb265] (backtrace.c:53) DLSCCP NOTICE A-0-m3ua: Using ASP instance asp-clnt-A-0-m3ua (sccp_user.c:695) DLSS7 NOTICE 0: Creating SCCP instance (osmo_ss7.c:408) DMSC NOTICE A-0-m3ua msc-0: local (BSC) SCCP address: RI=SSN_PC,PC=0.23.3,SSN=BSSAP (osmo_bsc_sigtran.c:703) DMSC NOTICE A-0-m3ua msc-0: remote (MSC) SCCP address: RI=SSN_PC,PC=0.23.1,SSN=BSSAP (osmo_bsc_sigtran.c:705) DMSC NOTICE A-0-m3ua msc-0: binding SCCP user (osmo_bsc_sigtran.c:710) DLSS7 ERROR XUA_AS(as-clnt-A-0-m3ua)[0x556b31b42cc0]{AS_INACTIVE}: Event AS-TRANSFER.req not permitted (m3ua.c:510) DLM3UA NOTICE 0: asp-asp-clnt-A-0-m3ua: Received NOTIFY Type State Change:AS Inactive () (m3ua.c:625) DLSS7 NOTICE xua_default_lm(asp-clnt-A-0-m3ua)[0x556b31b445c0]{ACTIVE}: Ignoring primitive M-ASP_ACTIVE.confirm (xua_default_lm_fsm.c:400) DLM3UA NOTICE 0: asp-asp-clnt-A-0-m3ua: Received NOTIFY Type State Change:AS Active () (m3ua.c:625) DMSC NOTICE RESET ACK from MSC: RI=SSN_PC,PC=0.23.1,SSN=BSSAP (osmo_bsc_bssap.c:84) DRESET NOTICE bssmap_reset(msc-0)[0x556b31b45790]{CONNECTED}: link up (bssmap_reset.c:83) DMSC NOTICE (msc0) BSSMAP association is up (a_reset.c:45) DLINP NOTICE 0.0.0.0:3002 accept()ed new link from 127.0.0.1:38477 (ipa.c:318) DLINP NOTICE Keepalive is set: 0 (ipaccess.c:612) DNM NOTICE OC=BTS(01) INST=(00,ff,ff): Get Attributes Response: feature 'GPRS' is supported (abis_nm.c:599) DNM NOTICE OC=BTS(01) INST=(00,ff,ff): Get Attributes Response: feature 'EGPRS' is supported (abis_nm.c:599) DNM NOTICE OC=BTS(01) INST=(00,ff,ff): Get Attributes Response: feature 'HOPPING' is supported (abis_nm.c:599) DNM NOTICE OC=BTS(01) INST=(00,ff,ff): Get Attributes Response: feature 'MULTI_TSC' is supported (abis_nm.c:599) DNM NOTICE OC=BTS(01) INST=(00,ff,ff): Get Attributes Response: feature 'OML_ALERTS' is supported (abis_nm.c:599) DNM NOTICE OC=BTS(01) INST=(00,ff,ff): Get Attributes Response: feature 'CBCH' is supported (abis_nm.c:599) DNM NOTICE OC=BTS(01) INST=(00,ff,ff): Get Attributes Response: feature 'SPEECH_F_V1' is supported (abis_nm.c:599) DNM NOTICE OC=BTS(01) INST=(00,ff,ff): Get Attributes Response: feature 'SPEECH_H_V1' is supported (abis_nm.c:599) DNM NOTICE OC=BTS(01) INST=(00,ff,ff): Get Attributes Response: feature 'SPEECH_F_EFR' is supported (abis_nm.c:599) DNM NOTICE OC=BTS(01) INST=(00,ff,ff): Get Attributes Response: feature 'SPEECH_F_AMR' is supported (abis_nm.c:599) DNM NOTICE OC=BTS(01) INST=(00,ff,ff): Get Attributes Response: feature 'SPEECH_H_AMR' is supported (abis_nm.c:599) DNM NOTICE OC=BTS(01) INST=(00,ff,ff): Get Attributes Response: feature 'ETWS_PN' is supported (abis_nm.c:599) DNM NOTICE OC=BTS(01) INST=(00,ff,ff): Get Attributes Response: feature 'PAGING_COORDINATION' is supported (abis_nm.c:599) DNM NOTICE OC=BTS(01) INST=(00,ff,ff): Get Attributes Response: feature 'IPV6_NSVC' is supported (abis_nm.c:599) DNM NOTICE OC=BTS(01) INST=(00,ff,ff): Get Attributes Response: feature 'ACCH_REP' is supported (abis_nm.c:599) DNM NOTICE OC=BTS(01) INST=(00,ff,ff): Get Attributes Response: feature 'CCN' is supported (abis_nm.c:599) DNM NOTICE OC=BTS(01) INST=(00,ff,ff): Get Attributes Response: feature 'VAMOS' is supported (abis_nm.c:599) DNM NOTICE OC=BTS(01) INST=(00,ff,ff): Get Attributes Response: feature 'ABIS_OSMO_PCU' is supported (abis_nm.c:599) DNM NOTICE OC=BTS(01) INST=(00,ff,ff): Get Attributes Response: feature 'BCCH_PWR_RED' is supported (abis_nm.c:599) DNM NOTICE OC=BTS(01) INST=(00,ff,ff): Get Attributes Response: feature 'DYN_TS_SDCCH8' is supported (abis_nm.c:599) DNM NOTICE OC=BTS(01) INST=(00,ff,ff): Get Attributes Response: feature 'ACCH_TEMP_OVP' is supported (abis_nm.c:599) DNM NOTICE OC=BTS(01) INST=(00,ff,ff): Get Attributes Response: feature 'VBS' is supported (abis_nm.c:599) DNM NOTICE OC=BTS(01) INST=(00,ff,ff): Get Attributes Response: feature 'VGCS' is supported (abis_nm.c:599) DNM NOTICE OC=BTS(01) INST=(00,ff,ff): ARI reported sw[0/2]: osmobts is 1.7.0.54-82a2 (abis_nm.c:652) DNM NOTICE OC=BTS(01) INST=(00,ff,ff): Reported variant: osmo-bts-trx (abis_nm.c:534) DNM ERROR OC=RADIO-CARRIER(02) INST=(00,00,ff): Attribute SW Configuration is unreported (abis_nm.c:557) DNM ERROR OC=BASEBAND-TRANSCEIVER(04) INST=(00,00,ff): Attribute Manufacturer Dependent State is unreported (abis_nm.c:557) DNM NOTICE OC=BASEBAND-TRANSCEIVER(04) INST=(00,00,ff): ARI reported sw[0/1]: TRX_PHY_VERSION is Unknown (abis_nm.c:652) DLINP NOTICE 0.0.0.0:3003 accept()ed new link from 127.0.0.1:37491 (ipa.c:318) DLINP NOTICE Keepalive is set: 0 (ipaccess.c:612) ... Is it something I should worry about? Thanks

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CRM Assignment Help at Your Fingertips
by fa318991＠gmail.com 06 Feb '24

06 Feb '24

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06 Feb '24

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libosmocore/BSC/MSC: MO voice calls rejected from Siemens S11E (patch included)
by Lennart Müller 31 Jan '24

31 Jan '24

Hi, I had a problem placing MO GSM calls from a Siemens S11E: The calls were dropped immediately; Osmo-MSC reports "Cannot compose Channel Type from bearer capabilities" After investigating the SETUP request from the S11E, the phone does not use octet 3a (no extension bit set in IE 3). Wireshark decodes the radio channel requirement as "Full rate support only MS/fullrate speech version 1 supported", so I added a condition to the gsm48_ie.c function of libosmocore to include at least GSM FR in the list of available speech_ver in case octet 3 has no extension. Attached to this message are the Abis-IP PCAP traces of MO calls, and the patch for gsm48_ie.c. Regards, Lennart

6 6

Problem while running NIB on Open Cellular Base sation
by Brackley Casinga 31 Jan '24

31 Jan '24

Hi, My name is Brackley Cassinga Form DRC, we run a community network called pamoja net where we offer gsm services using osmocom open source software and OC Base station. Recently I have tried to install another base station as the same installed but I could not find any resource guiding through all the steps to take to run NIB on a base station. I'm currently running Ubuntu and I will appreciate if you could guide me on the installation of BSC,hlr,MSC , in order to run a basic gsm network. Thank you. Regards -- *Ir Brackley heshima Casinga **Pacifique* *CEO and Founder of kwanzatechnologie* KwanzaTechnologies ,GlobalElectronics +243977265291 | +243977265291 | Pcassinga(a)gmail.com/ brackley(a)ensemblepourladifference.org www.kwantechnologies.jimdosite.com <http://www.kwantechnologies.com/> | Skype: Brackley cassinga <https://webapp.wisestamp.com/#> Av Semliki N 43

2 1

Helping an Australian set up his own personal GSM/2G cell
by Mychaela Falconia 28 Jan '24

28 Jan '24

Hello Osmocom community, I have a contact in Australia who reached out to me with a desire to set up his own personal GSM/2G network. Australia is a nasty anti- retrotechnology country, even worse than USA, where all official 2G networks were shut down back in 2018. As most of you know, I run my own pirate-radio GSM cell in USA, and I tried reaching out to other Vintage Mobile Phone communities, promoting the idea that people can run their own networks using Osmocom CNI plus suitable hw plus my ThemWi add-ons for outside PSTN interconnection, and offering to teach others how to copy what I am doing. When I made the latter offer to the community, I was expecting people from other parts of USA - but right now the only person with an active interest is in Australia. I am currently teaching my Australian contact the "pure physics" aspects of running your own GSM network: what frequencies are usable for GSM, dB and dBm units of measurements, how to use a handheld spectrum analyzer etc. These are all "physics" topics that are independent of where one happens to be geopolitically. But there is another key aspect which I feel he needs to know, but which I won't be able to teach him: country-specific spectrum-political aspects. I know the spectrum-political landscape in USA: how FCC has divvied up PCS1900 and GSM850 bands (or B2 & B5 in modern parlance) between carriers, which spots in these bands are completely unused and thus reasonably safe to squat in, and how one can exploit the overlap between EGSM900 DL and USA ISM band to run a BTS with low probability of getting into trouble. But I have absolutely no such knowledge for any other country in the world, let alone one as remote and foreign to me as Australia. Is there anyone in this community who is based in Australia and knows this topic? I would greatly appreciate any advice from an AU-knowing person that I could pass to my GSM-enthusiast contact: out of the 4 frequency bands that are in-principle suitable for GSM, which is the safest one to squat in for a pirate operator, and which ARFCN range(s)? Obviously I will teach my contact that he needs to pick a spot where the spectrum analyzer shows nothing but noise floor, but just because a spot "looks blank" on an SA doesn't mean that the spot is safe to squat on, without knowing anything at all about the country's spectrum-political landscape... TIA, Mychaela

2 1

Osmocom with limesdr Mini 2.0
by jheyrendt.ext＠orange.com 26 Jan '24

26 Jan '24

Dear all We have a questions for you, experts. Has anyone managed to get Osmocom with limesdr Mini 2.0 ? (USB) We have stability issues, so if someone has tried and can share configuration for osmocom-bsc and osmocom-trx-lms, it woud be great ! Many thanks in advance, Best regards

1 0

Open Source Involvement
by Tanya P 24 Jan '24

24 Jan '24

Good Morning, My name is Tanya and was referred to this email regarding open source involvement. I am genuinely interested in sysmocom and am open to exploring various ways I can support your team. If there are any upcoming opportunities or specific areas where my skills could be of value in a volunteer capacity, I would be grateful for the chance to discuss them further. Please take a look at my GitHub profile: https://github.com/wonntann Thank you again for your consideration. I look forward to the possibility of contributing to sysmocom and will continue to follow your updates. Best, Tanya

2 1

leave
by Roland Martinson 03 Jan '24

03 Jan '24

1 0

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