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Bug #3532

CBCH presence no longer advertised in SI4 since timeslot FSM was merged

Added by laforge about 1 month ago. Updated about 1 month ago.

Status:
Resolved
Priority:
High
Assignee:
Category:
-
Target version:
-
Start date:
09/09/2018
Due date:
% Done:

100%

Spec Reference:
Tags:

Description

It appears that during the merge of the timeslot FSM, CBCH handling in OsmoBSC was broken.

The SI4 message as sent in the RSL BCCH FILL doesn't advertise the CBCH channel description, even if a CBCH-enabled channel combination is configured.


Related issues

Related to OsmoBTS - Bug #1617: osmo-bts-trx doesn't support CBCHIn Progress2016-02-23

History

#1 Updated by laforge about 1 month ago

  • Status changed from New to In Progress
  • % Done changed from 0 to 40

See https://gerrit.osmocom.org/#/c/osmo-bsc/+/10851 for a first patch. However, now osmo-bsc ASSERTs in generate_si4() because gsm48_lchan2chan_desc() is used, which again uses "pchan_is", which is set to NONE at the time :(

One solution would be to postpone/delay RSL initialization to after OML initialization has fully completed.

Right now we're generating SI4 and other SI during bootstrap_rsl()
  • bootstrap_rsl() as a consequence to the RSL TCP connection coming up
  • RSL TCP connection coming up as result of IPA RSL CONNECT being sent via OML
  • and that in turn is a consequence of OPSTART_ACK on the baseband transceiver MO

There is a timeslot FSM now, but there's sill no TRX/BTS FSMs as parent. If we had those, they could receive some kind of indication from their children about completion of OML initialization, and we could delay sending the IPA RSL CONNECT.

#2 Updated by laforge about 1 month ago

  • Priority changed from Urgent to High
  • % Done changed from 40 to 90

see https://gerrit.osmocom.org/#/c/osmo-bsc/+/10854 for the second related patch. If both patches are applied, CBCH presence is again correctly indicated in SI4.

#3 Updated by laforge about 1 month ago

  • Status changed from In Progress to Resolved
  • % Done changed from 90 to 100

patches merged

#4 Updated by laforge about 1 month ago

  • Related to Bug #1617: osmo-bts-trx doesn't support CBCH added

#5 Updated by laforge about 1 month ago

  • Tags set to SMSCB
  • Project changed from OpenBSC to OsmoBSC

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