OpenBTS with GPRS....trouble with SGSN and PCU

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altaf sk altaf329 at gmail.com
Thu Jun 13 15:29:01 UTC 2013


Hello everybody.

Log from Osmo-SGSN

<0010> gprs_ns.c:171 NSVCI=65534 Creating NS-VC
<0010> gprs_ns.c:171 NSVCI=65535 Creating NS-VC
<0010> gprs_ns.c:819 Creating NS-VC for BSS at 192.168.111.144:23000
<0010> gprs_ns.c:692 NSEI=65535 Rx NS RESET (NSVCI=0, cause=O&M
intervention)
<0010> gprs_ns.c:547 NSEI=101 Tx NS RESET ACK (NSVCI=101)
<0010> gprs_ns.c:863 NSEI=101 Rx NS RESET ACK
<0010> gprs_ns.c:692 NSEI=101 Rx NS RESET (NSVCI=101, cause=O&M
intervention)
<0010> gprs_ns.c:547 NSEI=101 Tx NS RESET ACK (NSVCI=101)
<0010> gprs_ns.c:863 NSEI=101 Rx NS RESET ACK

These set of statements repeats as the NS reset timer timed out.
When a reset request is made to the NS, According to the code and specs the
NS-VC is blocked and made Alive.


Here is the log from PCU
<0001> pcu_l1_if.cpp:296 RACH request received: sapi=1 qta=4, ra=124,
fn=784700
<0008> gprs_rlcmac.cpp:1794 LLC [PCU -> SGSN] TFI: 0 TLLI: 0x7b9af47b len=44
<0007> gprs_rlcmac_meas.cpp:102 UL RSSI of TLLI=0x7b9af47b: -74 dBm

<0001> pcu_l1_if.cpp:296 RACH request received: sapi=1 qta=4, ra=124,
fn=785415
<0008> gprs_rlcmac.cpp:1794 LLC [PCU -> SGSN] TFI: 0 TLLI: 0x797c478f len=47
<0007> gprs_rlcmac_meas.cpp:102 UL RSSI of TLLI=0x797c478f: -58 dBm

These set of statements repeat.

As I receive a UL TBF on TS1 and when a request from PCU that calls
gprs_ns_sendmsg() inorder to send data to SGSN, it fails because the NS-VC
is still blocked and I also checked whether it is ALIVE or not, I find it
is Dead.

The MS (requesting for GPRS attach keeps on requesting for RACH and
responds on TS:1 with a TBF)

I am using
Libosmocore->jolly/trx
Openbsc->jolly/testing
OsmoBTS->jolly/trx
OsmoPCU->Master
OsmocomBB->Jolly/trx

I start as ./osmo-nitb   ./osmo-sgsn   ./Osmo-pcu
 ./transceiver(osmocom_bb) ./osmo-bts-trx

I compiled PCU as ./configure --enable--sysmocom-bts and osmo-bts as
./configure --enable-trx
If I dont compile PCU this way its not connecting with Osmo-BTS
and in OpenBSC I specified as sysmobts in the openbsc.cfg

Can you please guide and correct me in making the NS-VC alive and unblocked
and how can the PDU reach sgsn.

best regards,

Altaf


On Tue, Jun 11, 2013 at 4:50 PM, altaf sk <altaf329 at gmail.com> wrote:

> Hello Andreas
>
> 1.
> As you mentioned use OpenBSC -> master and OsmoBTS -> jolly/trx branch.
> Compiling OsmoBTS results in compilations errorrs.
>
> Log from OsmoBTS:
>
> rsl.c:138:2: warning: #warning merge lchan_lookup with OpenBSC [-Wcpp]
> rsl.c: In function ‘rsl_rx_chan_activ’:
> rsl.c:744:53: error: ‘struct gsm_lchan’ has no member named ‘mr_bts_lv’
> rsl.c:748:15: error: ‘struct gsm_lchan’ has no member named ‘mr_bts_lv’
> rsl.c: In function ‘rsl_rx_mode_modif’:
> rsl.c:991:53: error: ‘struct gsm_lchan’ has no member named ‘mr_bts_lv’
> rsl.c:995:15: error: ‘struct gsm_lchan’ has no member named ‘mr_bts_lv’
> rsl.c: In function ‘rsl_rx_ipac_XXcx’:
> rsl.c:1304:7: warning: passing argument 3 of ‘osmo_rtp_get_bound_ip_port’
> from incompatible pointer type [enabled by default]
> /usr/local/include/osmocom/trau/osmo_ortp.h:71:5: note: expected ‘int *’
> but argument is of type ‘uint16_t *’
> make[2]: *** [rsl.o] Error 1
> make[2]: Leaving directory `/home/cinterion/alt_cint/osmo-bts/src/common'
> make[1]: *** [all-recursive] Error 1
> make[1]: Leaving directory `/home/cinterion/alt_cint/osmo-bts/src'
> make: *** [all-recursive] Error 1
>
> 2.
>
> No errors when OpenBSC -> jolly/testing and OsmoBTS->jolly/trx. But cannot
> start OsmoSGSN when OpenBSC is on Jolly/tetsing.
>
> OsmoSGSN says :
>
> <0010> gprs_ns.c:171 NSVCI=65534 Creating NS-VC
> <000f> sgsn_libgtp.c:571 Failed to create GTP: -1
> <000f> sgsn_main.c:346 Cannot bind/listen on GTP socket
>
>
> So after compiling OsmoBTS, I switch OpenBSC->master and then start
> OsmoSGSN and it starts.
>
> Then OsmoSGSN  says :
> <0010> gprs_ns.c:171 NSVCI=65534 Creating NS-VC
>
> 3.
>
> I was able to connect the PCU to OsmoBTS... I compiled PCU with sysmo-bts
> support then it connected to osmoBTS.  I could also use the second phone
> for TS1 and was able to send a IMM ASS (for packet channel). I verified
> this on the MS (requesting for GPRS attach). And by observing log from PCU
> it shows MS has responded in TS-1 and sent data.
>
> OsmoNITB is also working good.
>
> Log from PCU when a GPRS attch request is received
>
> ./osmo-pcu -c osmo-pcu.cfg -m 234 -n 06
> <0001> sysmo_sock.cpp:292 PCU-SYSMO socket has been connected
> <0001> pcu_l1_if.cpp:375 BTS available
> <0001> pcu_l1_if.cpp:91 Sending activate request: trx=0 ts=1
> <0001> pcu_l1_if.cpp:502 PDCH: trx=0 ts=1
> <0001> pcu_l1_if.cpp:296 RACH request received: sapi=1 qta=4, ra=120,
> fn=741687
> <0008> gprs_rlcmac.cpp:1793 LLC [PCU -> SGSN] TFI: 0 TLLI: 0x7b15c7c4
> len=41
> <0007> gprs_rlcmac_meas.cpp:102 UL RSSI of TLLI=0x7b15c7c4: -59 dBm
> <0001> pcu_l1_if.cpp:296 RACH request received: sapi=1 qta=4, ra=120,
> fn=744933
> <0008> gprs_rlcmac.cpp:1793 LLC [PCU -> SGSN] TFI: 0 TLLI: 0x7b15c7c4
> len=41
> <0007> gprs_rlcmac_meas.cpp:102 UL RSSI of TLLI=0x7b15c7c4: -60 dBm
>
>
> Log from OsmoBTS when GPRS attch request is received
> When a UL data received on PDTCH
>
> <000a> trx_if.c:178 No response from transceiver
> <0006> scheduler.c:1169 Received RACH fn=754683 toa=1.51
> <0006> scheduler.c:1338 Received bad PDTCH block ending at fn=754809
> (81/104) for
>             PDTCH
> <000a> trx_if.c:178 No response from transceiver
>
> After this OsmoBTS results in
>
> Segmentation fault (core dumped)
>
>
> Can you please tell how can I compile OsmoBTS correctly by using
> OpenBSC->master.
>
>
> regards,
>
> Altaf
>
>
>
>
>
> On Wed, Jun 5, 2013 at 6:37 PM, altaf sk <altaf329 at gmail.com> wrote:
>
>> Hello andreas,
>>
>> thanks a lot for your help.
>>
>> I resulted successful in running the osmoBTS with calypso phones.
>> Currently I did (register) with 1 phone but will do it with 2 also.  yes I
>> am using the debugging option.
>>
>> Can you kindly tell me how should I enable the PCU support. I have the
>> osmo-pcu (master) installed and I start it before  starting osmoBTS.
>>
>> I tried to use jolly_test in osmo-pcu git, but errors concerning sysmobts.
>>
>> I tried looking around sockets and vty but could not figure it out. I
>> looked at the osmo-bts-sysmo code which has the command line option (-M
>> --pcu-direct) to enable pcu support.
>> I looked at the code and I found that pcu_direct is set to 1
>> (pcu_direct=1) when -M option is used.
>>
>> using this as a reference in the main.c of osmo-bts-trx i directly
>> defined pcu_direct=1 and then tried. The socket /tmp/pcu-bts is open but
>> still I dont see any response from PCU.
>>
>> Can you suggest me in this regard.
>>
>> regards,
>>
>> Altaf
>>
>>
>> On Tue, Jun 4, 2013 at 5:13 PM, altaf sk <altaf329 at gmail.com> wrote:
>>
>>> Yes, I understand how trx uses two phones by reading your previous
>>> commits. I will study them
>>>
>>>
>>> regards,
>>>
>>> altaf
>>>
>>>
>>>
>>> On Tue, Jun 4, 2013 at 4:53 PM, altaf sk <altaf329 at gmail.com> wrote:
>>>
>>>> ok. Thank you...
>>>>
>>>> I will look into this and will post if any success..
>>>>
>>>>  You say that using jolly/testing branch it is possible to use two
>>>> phones.  I am not sure how to use two phones and connect and how is the
>>>> sync b/w them. Can you please give some brief idea before you write
>>>> documentation.
>>>>
>>>> isnt it possible with 1 phone, Just for minimal functions.?
>>>>
>>>> I don't find the branch jolly/trx in git clone git://
>>>> github.com/chemeris/openbts-p2.8.git. Should I clone from a different
>>>> git.
>>>>
>>>>
>>>>
>>>>
>>>> On Tue, Jun 4, 2013 at 4:13 PM, jolly <andreas at eversberg.eu> wrote:
>>>>
>>>>> altaf sk wrote:
>>>>> > PCU -> master
>>>>> > bts   -> gprs-work
>>>>> > os_BB -> sylvain/testing
>>>>> > openbsc -> master
>>>>> pcu master is ok (everything merged).
>>>>> openbsc master is ok.
>>>>> bts gprs-work? i don't know this branch, please use jolly/trx.
>>>>> osmocom_bb you should use jolly/testing branch, because you need to use
>>>>> two phones, one for broadcast and one for timeslot 1 (gprs). i think i
>>>>> need to write a documentation for that. but in your case, the IMM.ASS
>>>>> problem must be solved first.
>>>>>
>>>>
>>>>
>>>
>>
>
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