4 May
2012
4 May
'12
8:25 a.m.
Hello,
I use OpenBSC/GPRS (sw version only few weeks old) with nanoBTS and this works well mith
many mobile devices.
With Nokia devices, however, I do not get a PDP context. Here is an osmo-sgsn trace of
Nokia E65:
<0012> gprs_bssgp.c:347 BSSGP TLLI=0x795b37eb Rx UPLINK-UNITDATA
<0013> gprs_llc.c:478 LLC SAPI=1 C FCS=0xc2ab0aCMD=UI DATA
<0013> gprs_llc.c:742 LLC RX: unknown TLLI 0x795b37eb, creating LLME on the fly
<0002> gprs_gmm.c:636 -> GMM ATTACH REQUEST MI(001011474110317) type="GPRS
attach"
<0002> gprs_gmm.c:351 <- GPRS ATTACH ACCEPT (new P-TMSI=0x78bb36bb)
<0012> gprs_bssgp.c:523 BSSGP BVCI=2 Rx Flow Control MS
<0012> gprs_bssgp.c:523 BSSGP BVCI=2 Rx Flow Control MS
<0012> gprs_bssgp.c:347 BSSGP TLLI=0xf8bb36bb Rx UPLINK-UNITDATA
<0013> gprs_llc.c:478 LLC SAPI=1 C FCS=0xc2ab0aCMD=UI DATA //remark: is a
repetition of GMM ATTACH REQUEST
<0013> gprs_llc.c:525 TLLI=f8bb36bb dropping UI, N(U=0) not in window V(URV(UR:1).
<0012> gprs_bssgp.c:347 BSSGP TLLI=0xf8bb36bb Rx UPLINK-UNITDATA
<0013> gprs_llc.c:478 LLC SAPI=1 C FCS=0x478a8dCMD=UI DATA
<0002> gprs_gmm.c:1047 -> ATTACH COMPLETE
<0012> gprs_bssgp.c:523 BSSGP BVCI=2 Rx Flow Control MS
<0012> gprs_bssgp.c:523 BSSGP BVCI=2 Rx Flow Control MS
<0012> gprs_bssgp.c:347 BSSGP TLLI=0xf8bb36bb Rx UPLINK-UNITDATA
<0013> gprs_llc.c:478 LLC SAPI=1 C FCS=0x478a8dCMD=UI DATA //remark: is a
repetition of ATTACH COMPLETE
<0013> gprs_llc.c:525 TLLI=f8bb36bb dropping UI, N(U=1) not in window V(URV(UR:2).
<0012> gprs_bssgp.c:347 BSSGP TLLI=0xf8bb36bb Rx UPLINK-UNITDATA
<0013> gprs_llc.c:478 LLC SAPI=1 C FCS=0x29e399CMD=UI DATA
<0002> gprs_gmm.c:782 -> GMM DETACH REQUEST TLLI=0xf8bb36bb type=GPRS detach
<0002> gprs_gmm.c:425 <- GPRS DETACH ACCEPT
<0012> gprs_bssgp.c:523 BSSGP BVCI=2 Rx Flow Control MS
<0012> gprs_bssgp.c:523 BSSGP BVCI=2 Rx Flow Control MS
<0012> gprs_bssgp.c:523 BSSGP BVCI=2 Rx Flow Control MS
We see some dropped frames here which are in fact retransmissions sent by the Nokia
device. After the successful GPRS Attach, the Nokia device refuses to send an ACTIVATE PDP
Context REQ. Most Nokia devices get asked for IMSI and IMEI during the GPRS ATTACH, which
her does not happen. However, these retransmissions are characteristical for all Nokia
devices I've tested so far (6021, C5, C7, E65, 3109c).
Is there a timing problem between osmo-sgsn and Nokia devices? Can I tune osmo-sgsn's
parameters to make the connection work?
Any help would be appreciated.
cheers
Olaf
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