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Bug #3057

OsmoBTS fails to schedule SACCH filling like SI5

Added by laforge over 1 year ago. Updated over 1 year ago.

Status:
Resolved
Priority:
Normal
Assignee:
Category:
-
Target version:
-
Start date:
03/11/2018
Due date:
% Done:

100%

Spec Reference:

Description

There are cases in which OsmoBTS is failing to schedule SACCH filling such as SYSTEM INFORAMTION 5.

This seems to be what's causing, among other things, #2963.

I've been instrumenting the code and found that the copying from BTS -> LCHAN is working as expected, and the lchan is started with valid information. Still, lchan_sacch_get() returns NULL for all but its first invocation.

It seems there is a corner case when we have exactly only one SACCH filling. If two or more are set, the loop seems to work. If only one SACCH filling is specified, it's transmitted once and then never again.

This bug seems to go back all the way to 2012. It might be that OsmoBSC in earler incarnations always sent SI5+SI6 and therefore the problem only became visible when only SI5 but no other SI is scheduled on SACCH.


Related issues

Related to Cellular Network Infrastructure - Bug #2963: Measurement Reports cease to be useful some time into a voice call / after handover (not sure which project has the bug / bugs yet)Resolved02/19/2018

Related to OpenBSC - Bug #3059: System Information on SACCH missing L2 Pseudo-LengthResolved03/11/2018

History

#1 Updated by laforge over 1 year ago

  • Related to Bug #2963: Measurement Reports cease to be useful some time into a voice call / after handover (not sure which project has the bug / bugs yet) added

#2 Updated by laforge over 1 year ago

  • Status changed from New to In Progress
  • % Done changed from 0 to 20

#3 Updated by laforge over 1 year ago

  • % Done changed from 20 to 80

proposed patch in https://gerrit.osmocom.org/#/c/7218/

TTCN-3 testcase is coming up as BTS_Tests.TC_sacch_filling

#4 Updated by laforge over 1 year ago

  • Status changed from In Progress to Resolved
  • % Done changed from 80 to 100

merged

#5 Updated by laforge over 1 year ago

  • Related to Bug #3059: System Information on SACCH missing L2 Pseudo-Length added

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