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Bug #3506

closed

FACCH LAPDm sequence error (state LAPD_STATE_MF_EST)

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

Status:
Closed
Priority:
High
Assignee:
Category:
osmo-bts-trx
Target version:
-
Start date:
08/28/2018
Due date:
% Done:

20%

Spec Reference:

Description

During a voice call (either TCH/F, or TCH/H), any FACCH activity (DTMF, call hold/retrieve) causes the following messages:

<0011> lapd_core.c:1556 N(S) sequence error: N(S)=7, V(R)=0 (dl=0x7fa23038d478 state LAPD_STATE_MF_EST) # Key press
<0011> lapd_core.c:1556 N(S) sequence error: N(S)=0, V(R)=1 (dl=0x7fa23038d478 state LAPD_STATE_MF_EST) # Key release
...
<0011> lapd_core.c:1556 N(S) sequence error: N(S)=3, V(R)=4 (dl=0x7fa23038d478 state LAPD_STATE_MF_EST) # Call hold
<0004> measurement.c:563 (bts=0,trx=0,ts=2,ss=0) No measurements for SUB!!!
<0004> measurement.c:563 (bts=0,trx=0,ts=2,ss=0) No measurements for SUB!!!
<0004> measurement.c:563 (bts=0,trx=0,ts=2,ss=0) No measurements for SUB!!!
<0004> measurement.c:563 (bts=0,trx=0,ts=2,ss=0) No measurements for SUB!!!
<0011> lapd_core.c:1556 N(S) sequence error: N(S)=4, V(R)=5 (dl=0x7fa23038d478 state LAPD_STATE_MF_EST) # Call retrieve
...

osmo-bts-trx 08062e6dcc8a0d1f869a1ce0b88238c8218546c3
Observed with both OsmocomBB and a regular phone.

Please see A-bis/RSL traffic capture attached to this report.


Files

facch.pcapng.gz facch.pcapng.gz 3.41 KB fixeria, 08/28/2018 10:24 AM
lapdm_seq_error.pcapng.gz lapdm_seq_error.pcapng.gz 3.83 KB fixeria, 04/04/2019 10:32 AM
lapdm_seq_error_facch.pcapng.gz lapdm_seq_error_facch.pcapng.gz 2.41 KB fixeria, 04/04/2019 06:33 PM

Related issues

Related to OsmoBTS - Feature #3906: Automatically adjust LAPDm timer values with 'fn-advance' parameterResolvedlaforge04/06/2019

Actions
Related to OsmoBTS - Bug #4466: " N(S) sequence error" when operating osmo-bts-trxRejectedsysmocom03/20/2020

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