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Bug #2733

Feature #2724: Improve default timers

T3101 default is way too large at 10s

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

Status:
Closed
Priority:
Normal
Assignee:
Category:
-
Target version:
-
Start date:
12/10/2017
Due date:
% Done:

100%

Spec Reference:

Description

As can be found in literature, 1.5s to 3s is a reasonable default, far away from our 10s.

the result is that we use the radio interface quite inefficiently, particularly in presence of RACH.

One problem is that the BSC doesn't really know when exactly to start T3101, as it doesn't know about
  1. the propagation delay on Abis to the BTS
  2. the queueing delay inside the BTS (due to queue length, AGCH load)
  3. the queueing delay inside the PHY/L1 (e.g. the OsmoTRX TRX/UDP protocol)

In order to cover at least the top two items, we could introduce a vendor-specific RSL message indicating when exactly the IMM.ASS had been sent on the radio interface.

Until such a non-3GPP solution is implemented, T3101 should have some reservation for the above delays. But for sure, 10s is completely over the top

History

#2 Updated by laforge over 1 year ago

  • Status changed from New to In Progress
  • Assignee set to laforge
  • % Done changed from 0 to 80

#3 Updated by laforge over 1 year ago

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

Changed to a more conservative 3s.

#4 Updated by laforge over 1 year ago

  • Status changed from Resolved to Closed

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