Project

General

Profile

Bug #3244

dyn TS: if the config is 'gprs mode none', dyn TS are stuck

Added by neels almost 3 years ago. Updated almost 3 years ago.

Status:
Resolved
Priority:
Normal
Assignee:
Category:
-
Target version:
-
Start date:
05/07/2018
Due date:
% Done:

100%

Spec Reference:

Description

Configure TCH/F_TCH/H_PDCH timeslots, keep 'gprs mode none'.

(bts=0,trx=0,ts=2,pchan=TCH/F_TCH/H_PDCH as NONE): GPRS mode is 'none': not activating PDCH.

subsequently dyn TS fail to register as TCH.

1. Activate TCH even if the dyn TS is in none state. (This should fix the situation even if 2 and 3 below are not implemented)
2. When GPRS is none, activate TCH from the start.
3. When GPRS is none and a voice call is done, keep TCH, don't switch over to PDCH.

Associated revisions

Revision 4281b7da (diff)
Added by Neels Hofmeyr almost 3 years ago

dyn TS: allow any pchan type changes, fix for gprs mode none

In rsl_chan_activate_lchan(), remove a condition to also allow switching pchan
modes when not in PDCH mode, which is actually not needed and would hinder
switching from pchan=NONE or between TCH/F <-> TCH/H.

Refactor the part where lchan_alloc() decides to switch a pchan mode into a
separate function, ts_usable_as_pchan(), which transparently checks both dyn TS
kinds for:

- Already in switchover? (missing check for ip.access style dyn TS)
- Is the lchan->state in error? (missing check for ip.access style dyn TS)
- Switch from pchan=NONE? (missing feature for Osmocom style dyn TS, for proper
handling with gprs mode none)
- Switch between TCH/F <-> TCH/H when all subslots are unused?
(missing feature for Osmocom style dyn TS, also useful for gprs mode none)

Always pass the desired pchan in the dyn_as_pchan argument to the lc_find*
functions to make switchover decisions transparent. Use the _lc_dyn_find_bts()
function for ip.access style dyn TS for the same reason.

Related: OS#3244
Change-Id: I72d5d833b186b1e1925d513885b405d8c19aa496

History

#1 Updated by neels almost 3 years ago

  • Tracker changed from Bug to Feature
  • Priority changed from Normal to Low

actually, we can require users to enable GPRS to be able to use dynamic timeslots, so this is more like a feature in the line of "if you have dyn TS, no need to change timeslot config if you disable GPRS".

So, an alternative way to resolve this would be to reject dyn ts timeslot config with GPRS disabled, or maybe just changing the log level to 'ERROR' could be enough?

#2 Updated by laforge almost 3 years ago

[osmocom style] dynamic timeslots make a lot of sense even without GPRS
in place. You can dynamically switch between TCH/F and TCH/H
dynamically, based on your need (or on whatever policy the BSC/MSC may
have). So I would argue it is very much valid to use them without GPRS.

On Mon, May 07, 2018 at 04:14:03PM +0000, neels [REDMINE] wrote:

So, an alternative way to resolve this would be to reject dyn ts
timeslot config with GPRS disabled, or maybe just changing the log
level to 'ERROR' could be enough?

For IPA style dynamic timeslots that could work, but for Osmocom-style,
see above comment.

Also, switching GPRS off administratively (e.g. temporarily, to debug
something) by using "gprs mode none" is quite common procedure. It's
not really nice if we force users to rewrite half of their config file
every time they want to enable or disable GPRS.

#3 Updated by laforge almost 3 years ago

  • Tracker changed from Feature to Bug
  • Priority changed from Low to Normal

#4 Updated by laforge almost 3 years ago

neels wrote:

1. Activate TCH even if the dyn TS is in none state. (This should fix the situation even if 2 and 3 below are not implemented)

sounds reasonable to me.

2. When GPRS is none, activate TCH from the start.

not a good idea, as you don't yet know if you'd need TCH/F or TCH/H at that point. I suggest to keep it in NONE until needed.

3. When GPRS is none and a voice call is done, keep TCH, don't switch over to PDCH.

I would rather suggest to switch to NONE in that situation. Otherwise the initial type (TCH/F or TCH/H) becomes permanent and not really dynamic anymore.

#5 Updated by neels almost 3 years ago

  • Priority changed from Normal to Low

indeed, thanks for correcting my too quick conclusions.

#6 Updated by neels almost 3 years ago

  • Priority changed from Low to Normal

what, when I commented, the UI for some reason switched back to "Low". That was not intended.

#7 Updated by neels almost 3 years ago

  • Status changed from New to Resolved
  • % Done changed from 0 to 100

Also available in: Atom PDF

Add picture from clipboard (Maximum size: 48.8 MB)