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Analysing the communication between the BSC and the MSC in a sysmoBTS
by Yann R. Moupinda 04 Oct '12

04 Oct '12

Hello everybody First of all, let me introduce myself. My name is Yann Moupinda and I'm a student doing his Master thesis in the field of GSM technology. For my thesis, the company for which i'm working now, bought a sysmoBTS from sysmocom. The sysmoBTS is configured as a stand alone GSM network in a box (NITB) running the osmo-nitb and the osmo-bts programs. An important part of my thesis is to understand how the sysmoBTS works and therefore I did some measurements with wireshark to analyse the data flow between the BTS,BSC and MSC/HLR/VLR/EIR. This is also to see the main differences between a sysmoBTS and a conventional GSM Network. I used the " tcpdump " - command on the loopback interface lo0 to capture the data flow between the GSM components and then, the analysis with wireshark shows me only the data flow between BTS and BSC. It's possible to see such messages like LOCATION UPDATING REQUEST and IDENTITY REQUEST wich are normally, transparently exchanged between Mobile Station (MS) and the Network subsystem (MSC/HLR/VLR/EIR). All these messages are always addressed to, or from the same BSC TCP-port 3003. So i can not see what happens behind this port (behind BSC). In order to get the communication between BSC and MSC, i decided to have a deeper look on the logging messages of the sysmoBTS. Even there, i cannot recognize how the data transmission between BSC and MSC works. Does anyone know how to get this information? Any guidance would be appreciated. I have included one .pcap file and a text file of the logging messages taken while i powered on the mobile phone. Best regards, Yann.

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OpenBSC and 3G
by John Otten 02 Oct '12

02 Oct '12

Hello Everyone, I now have OpenBSC (including GPRS) up and running with a fair amount of stability, using an IP.Access 2G BTS. Now I am looking towards the next stage - getting a 3G system operating. I have the use of an IP.Access NodeB that I would like get running with OpenBSC. In performing my due diligence, I found Harald's 3G road map from December 2010 or so. I am wondering what the current state of development is. I see that IP.Access' URSL protocol was an issue back then, because it is proprietary. Has anyone managed to get far enough in their development that they have implemented the protocol? I also see from Dieter Spaar's blog that he is making some progress, but he states his code is not ready for public release. Since I don't see much about 3G on the OpenBSC wiki, I am assuming that no one has any code that they would want to share at this point. I imagine I may have to forge ahead on my own. I am fairly new to GSM development, and I haven't really delved into the OpenBSC source yet (other than to discern what might have caused some problems I encountered), so if anyone has any suggestions on where to begin, or has some issues where I might be able to assist in order to move development further down the road, please let me know. Thanks! John

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Bounce action notification
by mailman＠lists.osmocom.org 30 Sep '12

30 Sep '12

This is a Mailman mailing list bounce action notice: List: OpenBSC Member: jledet07(a)student.aau.dk Action: Subscription disabled. Reason: Excessive or fatal bounces. The triggering bounce notice is attached below. Questions? Contact the Mailman site administrator at mailman(a)lists.osmocom.org.

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BS-11 to sell
by Harald Welte 30 Sep '12

30 Sep '12

Hi! In case anyone on this list is interested in owning a BS-11, I have decided to sell off one more of the units that I still had here for my personal use. I'm also able to sell a compatible HFC-E1 or DAHDI/Digium card along with it. Price is up to negotiation. I don't intend to give it away for free, unless it is somebody with a known track record of osmocom.org contributions. Regards, Harald -- - Harald Welte <laforge(a)gnumonks.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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Help needed with CSD/V.110 decoding
by Tobias Engel 27 Sep '12

27 Sep '12

Hi, I have been trying to implement some basic CSD functionality into openbsc. V.110 transparent mode, to be specific, since this should be the most simple to implement. At first I tried with a nanobts, but that didn't seem to work at all. Now I am using a bs-11. The two phones I use establish a connection, but they cannot exchange data and what I see on the Abis link also doesn't really make sense to me. (Needless to say everything works as expected when using the same phones on a production network.) I attached a pcap of a CSD call I made via the bs-11. The second attachment is the raw dump of the traffic frames I received from the BS-11 for _one_ of the phones. (It looks pretty much the same for the other phone.) The first idle data frames received look ok: 00000000 00 00 c5 ff ff ff ff ff fd ff ff ff ff ff ff ff 00000010 ff fd ff ff ff ff ff ff ff ff fd ff ff ff ff ff 00000020 ff ff ff fd ff ff ff ff C bits (Uplink data), D bits (all set to "1" == idle) and E bits (9.6 kbit/s) are all set as expected. But after the synchronisation phase, things start to get strange. The idle frames suddenly look like this: 00000460 00 00 8a ff ff fe fe fe fa fe fe fe fe fe fe fe 00000470 fe fa ff fe fe fe fe fe fe fe fa ff fe fe fe fe 00000480 fe fe fe fa ff fe fe fe The BTS "forgets" to set the first bit of every octet to "1" on most (but not all) octets. Also, the C bits now state that this is a 14.5kbit/s data frame. The E bits say the user rate now is 7.2 kbit/s. There are only four frames with actual payload data in the dump. These frames are at the positions I expect them to be (40600, 60520, 80440, 100400 - they were sent in intervals of 10 seconds). They look like this: 00009e90 00 00 8a ff 2b a2 fa aa 00009ea0 fa 86 02 22 22 6e fe 1a 26 fa d7 4e d6 52 36 56 00009eb0 4e d6 fa 53 36 56 4e d6 52 36 56 fa 4f d6 52 36 What has been sent by the phone is an eight byte timestamp followed by 22 bytes of 0xaa. But I only get one data frame for each of these transmissions (30 bytes of payload don't fit into one data frame), and if I parse it as V.110 data, I get these 20 bytes: 00000000 15 7d 0d 10 d5 ff 33 fb ae f5 ff ae ba ef fd ba 00000010 ef ae ba ff So no 0xaa bytes there... Does anybody have any idea what I might be doing wrong here? Thanks, -Tobias

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OpenBSC unsubscribe notification
by mailman-bounces＠lists.osmocom.org 26 Sep '12

26 Sep '12

akwonghk(a)gmail.com has been removed from OpenBSC.

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Re: OpenBSC Digest, Vol 45, Issue 15
by TAUFIQ WAHYUDI 25 Sep '12

25 Sep '12

@peter i have already installed libosmocore,libosmo-aabis,and openBsc,and have been clone and integrated all the items into eclipse via egit. i am a newbie in telco, does anyone in this forum know how to start up openBSC ? i do want to know how does the Box work, and really confuse how to start from.Would you guys send me a technical startup document globally, so then i have an understanding regarding this stuff Best Regards On 9/24/12, openbsc-request(a)lists.osmocom.org <openbsc-request(a)lists.osmocom.org> wrote: > Send OpenBSC mailing list submissions to > openbsc(a)lists.osmocom.org > > To subscribe or unsubscribe via the World Wide Web, visit > https://lists.osmocom.org/mailman/listinfo/openbsc > or, via email, send a message with subject or body 'help' to > openbsc-request(a)lists.osmocom.org > > You can reach the person managing the list at > openbsc-owner(a)lists.osmocom.org > > When replying, please edit your Subject line so it is more specific > than "Re: Contents of OpenBSC digest..." > > > Today's Topics: > > 1. new comer (TAUFIQ WAHYUDI) > 2. Re: new comer (Peter Stuge) > > > ---------------------------------------------------------------------- > > Message: 1 > Date: Sun, 23 Sep 2012 21:36:30 -0700 > From: TAUFIQ WAHYUDI <taufiq.wahyudi.12(a)gmail.com> > To: openbsc(a)lists.osmocom.org > Subject: new comer > Message-ID: > <CACxKs184Ma=PeW5sPi=HWWJm6xb+sqywmHBEgMs+XKKqiXEy+g(a)mail.gmail.com> > Content-Type: text/plain; charset="iso-8859-1" > > hi all, > > i am new comer in this group, i already have installed openbsc until to > this step, i have problems would you mind all giving me a hand in the > future? > > thank you very much > > Best Regards >

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GPRS and PDP Context
by John Otten 24 Sep '12

24 Sep '12

Good Day, I have been working with OpenBSC for the past few weeks and I am able to make voice calls and send SMS messages within the private network without issues. I am now attempting to add GPRS to the mix, and have been having less success. I have been able to make it to the internet from my phones occasionally, but in general, there appears to be an issue between osmo-sgsn and OpenGSN. My hope is that it is a simple configuration issue. However, I suspect it may be due to an issue in the code, or perhaps something mentioned last May (I have been scouring the mail archive) regarding foreign vs local TLLIs. My current setup is: One Linux workstation which runs all three pertinent executables: osmo-nitb, osmo-sgsn and ggsn. A nanoBTS 165BU (PCS1900) Two Nokia 6013b phones I am working in an RF chamber. I have some T-Mobile SIMs so, I have the network set to T-Mobile rather than the test network. I had previously been able to connect to the internet perhaps 1 in 10 times, presumably because the PDP contexts were not being created (the ggsn output would not state that it was creating a context when I tried to connect from the phone). I modified gprs_llc.c to handle the issue that Frank Maas mentioned in May, regarding llme_alloc not localizing the TLLI. Now, I can usually connect with a phone more consistently (but not always) on a fresh restart of the three executables. However, after connecting to the internet via the phone, if I cycle the power on the phone, I am usually not able to connect to the internet again. Sometimes the ggsn states that it "Received create PDP context request," and sometimes it doesn't state it when the sgsn (apparently) makes a request. At times, the ggsn reports "Received packet with no destination!!!" During these times, when I check the PDP contexts in osmo-sgsn, I get: OsmoSGSN> show pdp-context all PDP Context IMSI: 310260XXXXXXXXX, SAPI: 3, NSAPI: 5 APN: epc.tmobile.com PDP Address: IPv4 192.168.100.3 SGSN PDP Context Statistics: User Data Messages ( In): 0 (0/s 0/m 0/h 0/d) User Data Messages (Out): 0 (0/s 0/m 0/h 0/d) User Data Bytes ( In): 0 (0/s 0/m 0/h 0/d) User Data Bytes (Out): 0 (0/s 0/m 0/h 0/d) The times when the ggsn does not state that it received a create PDP context request, the "show pdp-context all" command shows nothing. My newbie guess is that osmo-sgsn is saving the state of the phone's connection (based on the IMSI?), and is not releasing or clearing it when the phone is powered off. When the phone is powered back on, it will have different connection parameters, but it will use the original parameters after retrieving them based on the IMSI. I have started to look through the code in the src/gprs directory to see if this is the case. I am wondering if anyone might have some insight into why the connection is not fully restored. Or perhaps they can offer guidance where I might begin to look in the code. I can send logs and pcap files of a typical session if anyone is interested. Thanks! John

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new comer
by TAUFIQ WAHYUDI 24 Sep '12

24 Sep '12

hi all, i am new comer in this group, i already have installed openbsc until to this step, i have problems would you mind all giving me a hand in the future? thank you very much Best Regards

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[PATCH] fix segfault during show running-config
by Max 21 Sep '12

21 Sep '12

--- src/vty/logging_vty.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/src/vty/logging_vty.c b/src/vty/logging_vty.c index 6166f1f..71d926d 100644 --- a/src/vty/logging_vty.c +++ b/src/vty/logging_vty.c @@ -547,7 +547,7 @@ static int config_write_log_single(struct vty *vty, struct log_target *tgt) for (i = 0; i < osmo_log_info->num_cat; i++) { const struct log_category *cat = &tgt->categories[i]; char cat_lower[32]; - + if (!osmo_log_info->cat[i].name) continue; /* stupid old osmo logging API uses uppercase strings... */ osmo_str2lower(cat_lower, osmo_log_info->cat[i].name+1); osmo_str2lower(level_lower, log_level_str(cat->loglevel)); -- 1.7.9.5 --------------080000000307010502010601--

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