GPRS - local and foreign TLLIs

[Nico Golde]

Hi,
* Harald Welte <laforge at gnumonks.org> [2011-01-25 14:59]:
> On Fri, Jan 21, 2011 at 06:44:03AM +0100, Luca Melette wrote:
> 
> > after setting up a nanoBTS with OpenBSC/SGSN/GGSN,
> > I had some troubles trying to connect my smartphone
> > to the GPRS cell.
> > 
> > Investigating the BTS-to-SGSN traffic, I saw that the
> > frames sent by the SGSN were all marked with the same
> > N(U) value (at LLC layer), the value was 0.
> > 
> > With some debug, I found that the there was a mismatch
> > in the TLLI storage, used to keep the status of attached
> > terminals.
> 
> This is probably related to some recent changes like
> f6bd340df6bcac716da78da8e35f379a7b853027 where I tried to fix the TLLI lookup
> in case a MS moves from one RA to another.  It seems instead of fixing it,
> I have made things worse.  Try to revert that patch...

I'm not completely sure if my problem is from the same 
origin (I just started to look into using openbsc with 
gprs). However this patch did not resolve my problem. What I 
see in osmo-sgsn is:
<0016> gprs_bssgp.c:346 BSSGP TLLI=0xa2d141c3 UPLINK-UNITDATA
<0017> gprs_llc.c:428 LLC SAPI=1 C   FCS=0x797ccfCMD=UI DATA
<0017> gprs_llc.c:117 TLLI 0xa2d141c3 is foreign, converting to local TLLI 0xe2d141c3
<0017> gprs_llc.c:700 LLC RX: unknown TLLI 0x08x, creating LLME on the fly
<0017> gprs_llc.c:117 TLLI 0xa2d141c3 is foreign, converting to local TLLI 0xe2d141c3
<0017> gprs_llc.c:342 LLC TX: unknown TLLI 0xa2d141c3, creating LLME on the fly
<0016> gprs_bssgp.c:346 BSSGP TLLI=0xa2d141c3 UPLINK-UNITDATA
<0017> gprs_llc.c:428 LLC SAPI=1 C   FCS=0xcd35c4CMD=UI DATA
<0017> gprs_llc.c:117 TLLI 0xa2d141c3 is foreign, converting to local TLLI 0xe2d141c3
<0017> gprs_llc.c:700 LLC RX: unknown TLLI 0x08x, creating LLME on the fly
<0017> gprs_llc.c:117 TLLI 0xa2d141c3 is foreign, converting to local TLLI 0xe2d141c3
<0017> gprs_llc.c:342 LLC TX: unknown TLLI 0xa2d141c3, creating LLME on the fly
<0017> gprs_llc.c:117 TLLI 0xa2d141c3 is foreign, converting to local TLLI 0xe2d141c3
<0017> gprs_llc.c:342 LLC TX: unknown TLLI 0xa2d141c3, creating LLME on the fly
<0017> gprs_llc.c:117 TLLI 0xa2d141c3 is foreign, converting to local TLLI 0xe2d141c3
<0017> gprs_llc.c:342 LLC TX: unknown TLLI 0xa2d141c3, creating LLME on the fly
<0016> gprs_bssgp.c:346 BSSGP TLLI=0xa2d141c3 UPLINK-UNITDATA
<0017> gprs_llc.c:428 LLC SAPI=1 C   FCS=0x804229CMD=UI DATA
<0017> gprs_llc.c:117 TLLI 0xa2d141c3 is foreign, converting to local TLLI 0xe2d141c3
<0017> gprs_llc.c:700 LLC RX: unknown TLLI 0x08x, creating LLME on the fly
<0002> gprs_gmm.c:213 Starting MM timer 3370 while old timer 3370 pending
<0017> gprs_llc.c:117 TLLI 0xa2d141c3 is foreign, converting to local TLLI 0xe2d141c3
<0017> gprs_llc.c:342 LLC TX: unknown TLLI 0xa2d141c3, creating LLME on the fly
<0017> gprs_llc.c:117 TLLI 0xa2d141c3 is foreign, converting to local TLLI 0xe2d141c3
<0017> gprs_llc.c:342 LLC TX: unknown TLLI 0xa2d141c3, creating LLME on the fly
<0017> gprs_llc.c:117 TLLI 0xa2d141c3 is foreign, converting to local TLLI 0xe2d141c3
<0017> gprs_llc.c:342 LLC TX: unknown TLLI 0xa2d141c3, creating LLME on the fly
<0016> gprs_bssgp.c:346 BSSGP TLLI=0xa2d141c3 UPLINK-UNITDATA
<0017> gprs_llc.c:428 LLC SAPI=1 C   FCS=0xfcdd5aCMD=UI DATA
<0017> gprs_llc.c:117 TLLI 0xa2d141c3 is foreign, converting to local TLLI 0xe2d141c3
<0017> gprs_llc.c:700 LLC RX: unknown TLLI 0x08x, creating LLME on the fly
<0002> gprs_gmm.c:213 Starting MM timer 3370 while old timer 3370 pending

openbsc before:
<0005> abis_nm.c:537 OC=GPRS-CELL(f1) INST=(00,00,ff) STATE CHG: OP_STATE=Enabled AVAIL=OK(ff) 

Which will repeat over and over again as long as the MS tries to connect.
There is only one RA in this scenario.

As mentioned I just started looking into gprs so any pointer 
on how to debug this further or add missing information are 
welcome. Apologies for hijacking this thread if this is a 
different problem.

Cheers
Nico