Losing ACKs due TLLI changes?

Andreas Eversberg andreas at eversberg.eu
Tue Nov 5 07:14:05 UTC 2013

Holger Hans Peter Freyther wrote:
> <0007> gprs_rlcmac_meas.cpp:103 UL RSSI of TLLI=0x88661bc6: -67 dBm
> <0002> bts.cpp:945 Got ACK, but UL TBF is gone TLLI=0xe512eba3
> <0007> gprs_rlcmac_meas.cpp:158 DL packet loss of IMSI=274080000004765 / TLLI=0xe512eba3: 0%
> <0002> tbf.cpp:668 TBF TFI=0 TLLI=0x88661bc6 T3169 timeout during transsmission
> <0002> tbf.cpp:690 - Assignment was on PACCH
> <0002> tbf.cpp:694 - No uplink data received yet
> So there is an ACK for TLLI=0xe512eba3 but at the same time the tlli
> 0x88661bc6 is timing out.
> PCU->SGSN TLLI=0x88661bc6 Attach Request
> SGSN->PCU TLLI=0x88661bc6 Attach Accept (new P-TMSI)
> PCU->SGSN TLLI=0xe512eba3 Attach Complete (new TLLI) (6s later)
hi holger,

can you provide the complete log, starting with the attach request? i
looked at the gprs_rlcmac_rcv_control_block() function which already
handles some TLLI change, but i am not sure if there is a bug or if
there must be some other way to handle TLLI change.



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