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Bug #4879

open

endless pdch.cpp:809 Got CS-N RLC block: R=0, SI=0, TFI=0, CPS=0, RSB=0, rc=264

Added by fixeria over 3 years ago. Updated 8 months ago.

Status:
Stalled
Priority:
High
Assignee:
Target version:
-
Start date:
11/30/2020
Due date:
% Done:

0%

Spec Reference:

Description

I just upgraded all osmo-{ran,cni} components to the recent master, and now quite often run into a situation when the MS (at least Sony Ericsson K800i, TEMS) keeps sending the same Uplink block again and again. I am not sure what exactly causes it, but I can reproduce it more or less reliably by starting Opera Mini (http://people.osmocom.org/fixeria/j2me/opera_mini.jar). When started for the first time, Opera initiates the installation process, and this is where the problem usually shows up.

DRLCMACUL INFO pdch.cpp:809 Got CS-2 RLC block: R=0, SI=0, TFI=0, CPS=0, RSB=0, rc=264
DRLCMACUL INFO pdch.cpp:809 Got CS-2 RLC block: R=0, SI=0, TFI=0, CPS=0, RSB=0, rc=264
DRLCMACUL INFO pdch.cpp:809 Got CS-2 RLC block: R=0, SI=0, TFI=0, CPS=0, RSB=0, rc=264
DRLCMACUL INFO pdch.cpp:809 Got CS-2 RLC block: R=0, SI=0, TFI=0, CPS=0, RSB=0, rc=264
DRLCMACUL INFO pdch.cpp:809 Got CS-2 RLC block: R=0, SI=0, TFI=0, CPS=0, RSB=0, rc=264
DRLCMACUL INFO pdch.cpp:809 Got CS-2 RLC block: R=0, SI=0, TFI=0, CPS=0, RSB=0, rc=264
DRLCMACUL INFO pdch.cpp:809 Got CS-2 RLC block: R=0, SI=0, TFI=0, CPS=0, RSB=0, rc=264
DRLCMACUL INFO pdch.cpp:809 Got CS-2 RLC block: R=0, SI=0, TFI=0, CPS=0, RSB=0, rc=264
DRLCMACUL INFO pdch.cpp:809 Got CS-2 RLC block: R=0, SI=0, TFI=0, CPS=0, RSB=0, rc=264
DRLCMACUL INFO pdch.cpp:809 Got CS-2 RLC block: R=0, SI=0, TFI=0, CPS=0, RSB=0, rc=264
DRLCMACUL INFO pdch.cpp:809 Got CS-2 RLC block: R=0, SI=0, TFI=0, CPS=0, RSB=0, rc=264
DRLCMACUL INFO pdch.cpp:809 Got CS-2 RLC block: R=0, SI=0, TFI=0, CPS=0, RSB=0, rc=264
DRLCMACUL INFO pdch.cpp:809 Got CS-2 RLC block: R=0, SI=0, TFI=0, CPS=0, RSB=0, rc=264
DRLCMACUL INFO pdch.cpp:809 Got CS-2 RLC block: R=0, SI=0, TFI=0, CPS=0, RSB=0, rc=264
DRLCMACUL INFO pdch.cpp:809 Got CS-2 RLC block: R=0, SI=0, TFI=0, CPS=0, RSB=0, rc=264
DRLCMACUL INFO pdch.cpp:809 Got CS-2 RLC block: R=0, SI=0, TFI=0, CPS=0, RSB=0, rc=264
DRLCMACUL INFO pdch.cpp:809 Got CS-2 RLC block: R=0, SI=0, TFI=0, CPS=0, RSB=0, rc=264
DRLCMACUL INFO pdch.cpp:809 Got CS-2 RLC block: R=0, SI=0, TFI=0, CPS=0, RSB=0, rc=264
DRLCMACUL INFO pdch.cpp:809 Got CS-2 RLC block: R=0, SI=0, TFI=0, CPS=0, RSB=0, rc=264
DRLCMACUL INFO pdch.cpp:809 Got CS-2 RLC block: R=0, SI=0, TFI=0, CPS=0, RSB=0, rc=264
DRLCMACUL INFO pdch.cpp:809 Got CS-2 RLC block: R=0, SI=0, TFI=0, CPS=0, RSB=0, rc=264
DRLCMACUL INFO pdch.cpp:809 Got CS-2 RLC block: R=0, SI=0, TFI=0, CPS=0, RSB=0, rc=264
DRLCMACUL INFO pdch.cpp:809 Got CS-2 RLC block: R=0, SI=0, TFI=0, CPS=0, RSB=0, rc=264
DRLCMACUL INFO pdch.cpp:809 Got CS-2 RLC block: R=0, SI=0, TFI=0, CPS=0, RSB=0, rc=264
DRLCMACUL INFO pdch.cpp:809 Got CS-2 RLC block: R=0, SI=0, TFI=0, CPS=0, RSB=0, rc=264
DRLCMACUL INFO pdch.cpp:809 Got CS-2 RLC block: R=0, SI=0, TFI=0, CPS=0, RSB=0, rc=264
DRLCMACUL INFO pdch.cpp:809 Got CS-2 RLC block: R=0, SI=0, TFI=0, CPS=0, RSB=0, rc=264
DRLCMACUL INFO pdch.cpp:809 Got CS-2 RLC block: R=0, SI=0, TFI=0, CPS=0, RSB=0, rc=264
DRLCMACUL INFO pdch.cpp:809 Got CS-2 RLC block: R=0, SI=0, TFI=0, CPS=0, RSB=0, rc=264
DRLCMACMEAS INFO gprs_rlcmac_meas.cpp:108 MS(TLLI=0xc5849e78, IMSI=901990000000021, TA=0, 10/0, UL DL) UL RSSI: -29 dBm

Please see the attached capture file. Some highlights:

43585 RACH!
43591 IMM ASS (single block)
43731 UL Packet Resource Request
43799 DL Packet Uplink Assignment (TS=6 USF=0)
...
43910 UL DATA (BSN=0 CV=15)
...
43915 UL DATA | TCP FIN,ACK (Opera Mini closes connection to the server)
...
43918 UL DATA (BSN=3 CV=15)
43955 UL DATA (BSN=5 CV=14)  <-- 14 RLC blocks left
...
44070 UL DATA (BSN=14 CV=5)
...
44146 UL DATA (BSN=19 CV=0)  <-- 0 RLC blocks left
...
44149 UL DATA (BSN=19 CV=0)  <-- re-transmission
44152 UL DATA (BSN=19 CV=0)  <-- re-transmission

starting from frame 44149, the MS keeps transmitting the same RLC/MAC block ('35bdc794cd2b631285b2d43513'O). Interestingly enough, after each re-transmission the PCU logs "GPRS DL CTRL: PACKET_UPLINK_ACK_NACK", but does not actually send it (dummy RLC/MAC frames are not recorded). And this goes like that unless I turn off the phone. At the same time, Downlink blocks are received and accepted by the MS on the same timeslot.

OsmoPCU 58cd1d2f8a0474de45112e8d6e460051494eba79
OsmoBTS def24f0d9af2463a5ef557d35f23abd5b4d07120


Files

pcu_loop.pcap.gz pcu_loop.pcap.gz 1.28 MB fixeria, 11/29/2020 11:11 PM
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