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

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altaf sk altaf329 at gmail.com
Tue Jun 11 14:50:55 UTC 2013


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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