Hi I any suggestion is welcome, I am bit stuck don't know how to proceed. regrads I am using OpenBSC/GPRS with nanoBTS. Thanks everybody for the great work. GPRS works well with many cell phone, but for particular cell phone its not working. I saw Olaf Schulz posting (subject: GPRS problems with Nokia Handsets dated 4th May 2012). Saw his pcap file and mine is similar too. Frank Mass suggested a patch to overcome this problem in his posting (subject gprs_llc.c foreighn TLLI is stored but not searched, dated 30 April 2012). I have implemented that patch but still not working. Can any body suggest something. Please find the osmo-sgsn trace <0011> gprs_bssgp.c:376 BSSGP TLLI=0xabfafd41 Rx UPLINK-UNITDATA <0012> gprs_llc.c:551 LLC SAPI=1 C FCS=0x76d7d9CMD=UI DATA <0012> gprs_llc.c:95 TLLI 0xabfafd41 is foreign, converting to local TLLI 0xebfafd41 <0012> gprs_llc.c:245 LLC RX: unknown TLLI 0xabfafd41, creating LLME on the fly <0011> gprs_bssgp.c:753 BSSGP BVCI=2 Rx Flow Control BVC <0011> gprs_bssgp.c:376 BSSGP TLLI=0xabfafd41 Rx UPLINK-UNITDATA <0012> gprs_llc.c:551 LLC SAPI=1 R FCS=0x57768eCMD=XID DATA <0011> gprs_bssgp.c:376 BSSGP TLLI=0xabfafd41 Rx UPLINK-UNITDATA <0012> gprs_llc.c:551 LLC SAPI=1 C FCS=0x9ab10aCMD=UI DATA <0012> gprs_llc.c:598 TLLI=abfafd41 dropping UI, N(U=0) not in window V(URV(UR:3). <0011> gprs_bssgp.c:753 BSSGP BVCI=2 Rx Flow Control BVC <0011> gprs_bssgp.c:753 BSSGP BVCI=2 Rx Flow Control BVC <0011> gprs_bssgp.c:376 BSSGP TLLI=0x7d3b00c1 Rx UPLINK-UNITDATA <0012> gprs_llc.c:551 LLC SAPI=1 C FCS=0xfd5011CMD=UI DATA <0012> gprs_llc.c:245 LLC RX: unknown TLLI 0x7d3b00c1, creating LLME on the fly <0011> gprs_bssgp.c:753 BSSGP BVCI=2 Rx Flow Control BVC <0011> gprs_bssgp.c:376 BSSGP TLLI=0x7d3b00c1 Rx UPLINK-UNITDATA <0012> gprs_llc.c:551 LLC SAPI=1 C FCS=0x11fb2fCMD=UI DATA <0011> gprs_bssgp.c:376 BSSGP TLLI=0x7d3b00c1 Rx UPLINK-UNITDATA <0012> gprs_llc.c:551 LLC SAPI=1 C FCS=0xea1c55CMD=UI DATA <0011> gprs_bssgp.c:753 BSSGP BVCI=2 Rx Flow Control BVC <0011> gprs_bssgp.c:753 BSSGP BVCI=2 Rx Flow Control BVC <0011> gprs_bssgp.c:376 BSSGP TLLI=0xe23c0990 Rx UPLINK-UNITDATA <0012> gprs_llc.c:551 LLC SAPI=1 C FCS=0x2a6a81CMD=UI DATA <000f> sgsn_libgtp.c:126 Create PDP Context <000f> sgsn_libgtp.c:379 libgtp cb_conf(type=16, cause=128, pdp=0x7feafc152320, cbp=0x6bcf50) <000f> sgsn_libgtp.c:265 Received CREATE PDP CTX CONF, cause=128(Request accepted) <0013> gprs_sndcp.c:297 SNSM-ACTIVATE.ind (lle=0x6bbe60 TLLI=e23c0990, SAPI=3, NSAPI=5) <0011> gprs_bssgp.c:753 BSSGP BVCI=2 Rx Flow Control BVC <0011> gprs_bssgp.c:753 BSSGP BVCI=2 Rx Flow Control BVC <0011> gprs_bssgp.c:753 BSSGP BVCI=2 Rx Flow Control BVC <0011> gprs_bssgp.c:376 BSSGP TLLI=0xe23c0990 Rx UPLINK-UNITDATA <0012> gprs_llc.c:551 LLC SAPI=1 C FCS=0x819789CMD=UI DATA <000f> sgsn_libgtp.c:212 Delete PDP Context <000f> sgsn_libgtp.c:402 PDP Context was deleted <000f> sgsn_libgtp.c:379 libgtp cb_conf(type=20, cause=128, pdp=(nil), cbp=0x6bcf50) <000f> sgsn_libgtp.c:321 Received DELETE PDP CTX CONF, cause=128(Request accepted) <0013> gprs_sndcp.c:320 SNSM-DEACTIVATE.ind (lle=0x6bbe60, TLLI=e23c0990, SAPI=3, NSAPI=5) John