OpenBSC May 2013

openbsc@lists.osmocom.org

18 participants
18 discussions

Testing Openbsc without a BTS
by Priyanka Behl 22 May '13

22 May '13

Hi everyone, I am trying to test Openbsc without a BTS. I need your help as I am very new to Openbsc. After doing the configurations for openbsc-multitrx.cfg file this is how I started the process: cd openbsc/openbsc src/osmo-nitb -c doc/examples/osmo-nitb/nanobts/openbsc-multitrx.cfg -C And the output I received was: <0019> input/ipaccess.c:925 enabling ipaccess BSC mode DB: Database initialized. DB: Database prepared. <0001d> sms_queue.c:220 Attempting to send 20 SMS After this I added a subscriber in the hlr and the subscriber was added in the output: <0019> ipaccess.c:841 enabling ipaccess BSC mode DB: Database initialized. DB: Database prepared. <001d> sms_queue.c:232 Attempting to send 20 SMS <0002> gsm_subsciber.c:390 Expiring inactive subscriber Testing(ID 1) After this I used the following commands on the osmo-nitb console and receive the following output: Openbsc>show subscrber id 1 ID: 1, Authorized: 1 Name: 'Testing' Extension: 9999999999 LAC: 0/0x0 IMSI: 404012345678903 TMSI: 0012D681 Pending: 0 Usecount: 1 Openbsc> subscriber id 1 send sms Hello Openbsc> subscriber id 1 silent call start any %subscriber not attached Am I doing the right thing, are there some more configurations that I am required to do and is this the only output that can be achieved without a BTS? Also the lac is being displayed as 0/0x0, is this how it should have been? Please let me know, I really need help on this. Thanks and regards Priyanka

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New handover algorithm
by jolly 16 May '13

16 May '13

Hi, Jean-Samuel and me developed an advanced handover algorithm for OpenBSC. Before implementing it, we would like to get any feedback, so I decided to post it in this mailing list. The document that describes the algorithm can be downloaded at: http://home.eversberg.eu/handover-algorithm-v2.3.pdf Regards, Andreas Handover shall ensure that the mobile station is always on the best cell during a call. This results in best speech quality and allows a lower TX level (up-link) to save battery and reduce interference. Sometimes this is not desirable, especially if a cell with large coverage becomes congested after handover. In this situation it makes sense to balance the usage between cells to prevent congestion. If a cell is congested, one or several mobile stations need to be handovered to a different cell, even if that cell is not the best cell for these mobile station. In case that a mobile station needs to handover to prevent a loss of radio link, it makes sense to handover it to a cell that is congested afterwards. In this situation, a different mobile station on the congested target cell must be handovered to a non-congested neighbor cell, to solve or balance the congestion. In order to negotiate used codec and TCH rate during call setup, Immediate Assignment shall assign an SDCCH channel, if available. After negotiation is complete, assignment to the available TCH slot is made.

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Testing Openbsc with software BTS
by Priyanka Behl 14 May '13

14 May '13

Hi, As per your mails about a pure software BTS when I tried installing it as: root@server:~# echo 'deb http://download.opensuse.org/repositories/home:/zecke23/Debian_6.0/ ./' > /etc/apt/sources.list.d/ I got the following error bash: /etc/apt/sources.list.d/: Is a directory so next i tried installing it as: root@server:~# echo 'deb http://download.opensuse.org/repositories/home:/zecke23/Debian_6.0/ ./' > /etc/apt/sources.list root@server:~# apt-get update Get:1 http://download.opensuse.org/ ./ Release.gpg [189 B] Ign http://download.opensuse.org/repositories/home:/zecke23/Debian_6.0/ ./ Translation-en Ign http://download.opensuse.org/repositories/home:/zecke23/Debian_6.0/ ./ Translation-en_IN Get:2 http://download.opensuse.org/ ./ Release [463 B] Ign http://download.opensuse.org/ ./ Release Ign http://download.opensuse.org/ ./ Packages/DiffIndex Ign http://download.opensuse.org/ ./ Packages Hit http://download.opensuse.org/ ./ Packages Fetched 190 B in 1s (145 B/s) Reading package lists... Done W: GPG error: http://download.opensuse.org/ ./ Release: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 7E816D4EB59F3637 root@server:~# gpg --keyserver pool.sks-keyservers.net --recv-keys 7E816D4EB59F3637 gpg: requesting key B59F3637 from hkp server pool.sks-keyservers.net gpgkeys: key 7E816D4EB59F3637 not found on keyserver gpg: no valid OpenPGP data found. gpg: Total number processed: 0 do you know how to troubleshoot this? Thanks and regards Priyanka ________________________________ From: Holger Hans Peter Freyther <holger(a)freyther.de> To: Priyanka Behl <priyankabehl(a)ymail.com> Cc: "openbsc(a)lists.osmocom.org" <openbsc(a)lists.osmocom.org> Sent: Thursday, 9 May 2013 1:59 PM Subject: Re: Testing Openbsc without a BTS On Thu, May 09, 2013 at 02:24:55PM +0800, Priyanka Behl wrote: Hi, > Hi everyone, > I am trying to test Openbsc without a BTS. I need your help as I am very new to Openbsc. > After doing the configurations for openbsc-multitrx.cfg file this is how I started the process: you might want to look at my mails about a pure software BTS used to test OpenBSC. The mails are here[1][2]. > cd openbsc/openbsc > src/osmo-nitb -c doc/examples/osmo-nitb/nanobts/openbsc-multitrx.cfg -C > Openbsc> subscriber id 1 send sms Hello > Openbsc> subscriber id 1 silent call start any > %subscriber not attached This is to be expected. Our system enforces a periodic location updating procedure and if a subscriber will not do that, it will be expired. Your subscriber needs to make a Location Updating Procedure. holger [1] http://lists.osmocom.org/pipermail/openbsc/2012-October/004210.html [2] http://lists.osmocom.org/pipermail/openbsc/2012-October/004250.html

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[PATCH] nat: fix use after free in forward_sccp_to_bts
by pablo＠gnumonks.org 12 May '13

12 May '13

From: Pablo Neira Ayuso <pablo(a)gnumonks.org> valgrind detected an use after free in the path of forward_sccp_to_bts. The 'parsed' object is referenced from update_con_authorize. --- openbsc/src/osmo-bsc_nat/bsc_nat.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/openbsc/src/osmo-bsc_nat/bsc_nat.c b/openbsc/src/osmo-bsc_nat/bsc_nat.c index b9bf36c..be8d56a 100644 --- a/openbsc/src/osmo-bsc_nat/bsc_nat.c +++ b/openbsc/src/osmo-bsc_nat/bsc_nat.c @@ -718,15 +718,18 @@ static int forward_sccp_to_bts(struct bsc_msc_connection *msc_con, struct msgb * LOGP(DNAT, LOGL_ERROR, "Unknown connection for msg type: 0x%x from the MSC.\n", parsed->sccp_type); } - talloc_free(parsed); - if (!con) + if (!con) { + talloc_free(parsed); return -1; + } if (!con->bsc->authenticated) { + talloc_free(parsed); LOGP(DNAT, LOGL_ERROR, "Selected BSC not authenticated.\n"); return -1; } update_con_authorize(con, parsed, msg); + talloc_free(parsed); bsc_send_data(con->bsc, msg->l2h, msgb_l2len(msg), proto); return 0; -- 1.7.10.4

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Silent Call vs Test Call vs A-bis Proxy (ip.access-proxy)
by j h 08 May '13

08 May '13

Could someone explain to me the difference between Silent Call, Test Call, and A-bis proxy (ip.access-proxy). To my understanding Test Call opens a pass through UDP port straight to the MS. While SilentCall just creates just creates a open channel. My confusion I believe comes from where you're "sitting" in the eco-system between Silent Call and Test Call. I also am confused after looking at ip.access-proxy. It clearly opens a port for injection either towards the BSC or BTS. However, does a silent-call need to be active to get data to the MS? When I try to inject a simple SMS using ip.access-proxy, (via copying traffic seen across ip.access), I get length disagrees with header. What is ip.access injection expecting in terms of data format? Thanks

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Stress-testing sysmobts of osmo-bts
by Holger Hans Peter Freyther 06 May '13

06 May '13

Hi, I have pushed zecke/work/msgq-reading2 with a work in progress improvement for handling a load from a stress-test. The stress test is to allocate all lchan's at the same time (then let them fail through the radio link timeout) and re-allocate them. This forces the BTS to constantly need to open/close the logical channel resources and also send some (idle) frames (LAPDm is not established in this case). The BTS was sending frames too late and after looking at it with perf it looked like a latency issue (no one is really using the CPU). I have implemented various changes, not all of them are ready: * Change the Bad-Frame-Indicator level to have radio link timeouts with no phone being present. In the above test-case channels remained open as there was no bad-frame-indication on these channels. Pro: There is a constant load for all open channels Bad: We could do this as part of the MphTimeInd but then need to add a bit to the counter to remember if the counter was modified and we need to handle bad frame in two places. * Use writev for the write_queue. This code should/could move into the libosmocore. So for our primitives queue all primitives are the same length and we can use writev to write several frames as the same time. 1.) We go through the queued messages and add them to the iovec 2.) We use writev 3.) We do written / prim_size to see how many buffers were written 4.) We go throuh the queued messages with llist_for_each_entry_safe and remove the count of messages sent. 5.) We check if there are messages left and re-set the notify on writable bit. * Use readv for reading from the queue. This means that we need to allocate N msgb's, call readv, dispatch the messages, free the extra msgb's. Pro: In idle mode there is at least one message to read, with channels open it is likely we will read several messages at once. Bad: Allocating memory is not free. We could start using talloc pools, we could add a msgb_alloc_headroom that does not memset (talloc_zero) the memory. * The above made noticable differences but I also had to get the realtime hammer. I have decided to use SCHED_RR (instead of SCHED_FIFO). This is done with osmo-pcu in mind that needs to read from queues as well and both bts/pcu should be able to inerrupt each other. * For the ts_meas_check_compute we can stop processing the entire TS once we reach a lchan of type lchan == GSM_LCHAN_NONE. (We still need to add a memset of the lchan array into the oml.c code in case there is a re-config). TCH/F: Only lchan[0] is used. TCH/H: Only lchan[0,1] are used. SDCCH8: All of them are used CCCH: lchan[4] is used but we will have no power measurements anyway CCCH/SDCCH4: lchan[0-3] are used. What is not done: * Change the l1if primitive to either use or 'steal' the msgb. All the msgb_free could be removed, only if we forward the MSGB to the PCU socket we would 'steal' it. This would allow us to avoid calling msgb_alloc and msgb_free most of the time. * Add SCHED_RR to the pcu code as well. * Create a talloc pool for the primitives (or re-use the msgb across multiple reads). please review and comment holger

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[EVENT ANNOUNCEMENT] Boston Open GSM Meetup on Friday 10 May 2013
by Robin Coxe 04 May '13

04 May '13

(Apologies for cross-posting. We wanted to reach everyone who might be interested in attending. Please respond responsibly.) Anders Brownworth (Switchcoder), Alexander Chemeris (Fairwaves), and Robin Coxe (Close-Haul Communications & Analog Devices) invite those interested in open GSM hardware and software development to an informal gathering in Cambridge, MA on Friday 10 May 2013 from 6-8 pm. Alexander will be visiting the Boston area from Moscow. If you are interested in participating in any capacity in the Boston-area open source GSM development community, we look forward to meeting you. Our goal is to identify like-minded people involved in or interested in learning more about projects such as OpenBTS, OsmocomBTS, OsmocomBB, and OpenBSC. If you have a portable, self-contained demo, feel free to bring it with you. When: Friday 10 May 2013, 6-8 pm EDT Where: Cambridge Innovation Center, 1 Broadway, 4th Floor, Cambridge, MA 02142 USA Photo ID required for building entry. Please RSVP on Eventbrite: http://opengsmboston.eventbrite.com/

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Uncaught bounce notification
by mailman-bounces＠lists.osmocom.org 01 May '13

01 May '13

The attached message was received as a bounce, but either the bounce format was not recognized, or no member addresses could be extracted from it. This mailing list has been configured to send all unrecognized bounce messages to the list administrator(s). For more information see: https://lists.osmocom.org/mailman/admin/openbsc/bounce

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OpenBSC May 2013