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Feature #4701

implement OsmoSTP notification of peers disconnecting, e.g. for OsmoBSC to detect that a specific MSC in the pool is disconnected

Added by neels 4 months ago.

Status:
New
Priority:
Normal
Assignee:
-
Target version:
-
Start date:
08/11/2020
Due date:
% Done:

0%

Spec Reference:

Description

This is a spin-off from the discussion in #4619 (where the MSC-pooling tests leave osmo-bsc in a state of assuming presence of MSCs that have disconnected)
and also related to #2623 (which is actually more about sending RESET upon re-connect)

The aim is to be able to immediately notify of disconnected peers across the STP (e.g. BSC <-> MSC).

laforge wrote:

On Fri, Aug 07, 2020 at 01:44:00PM +0000, neels [REDMINE] wrote:

Now I need to pinpoint what exactly the right mechanism would be for osmo-bsc to realize that an MSC is no longer connected.

Without any active calls (SCCP connections) you don't really know.

The only situations are:
  • SCCP connection timers timing out (if there are any active SCCP connections)
  • SCCP network informing the user about unavailability of a given point code
    • we don't imlpement this in Osmocom so far, but there are messages like
      M3UA DUNA/DAVA that can be used by an STP to notify M3UA ASPs like the BSC about
      availability/unavailability of a given point code.
    • libosmo-sigtan would have to parse such messages and send N-NOTICE.indication
      from the SCCP provider to the SCCP user (local SCCP user like MSC, BSC, ...),
      as well as N-INFO.indication for active SCCP connections

Related issues

Related to Cellular Network Infrastructure - Feature #2623: SCCP/M3UA: detect restart of osmo-msc and osmo-sgsnNew11/07/2017

Related to Cellular Network Infrastructure - Bug #4619: ttcn3-bsc-test: all LCLS test cases broken since build #987Resolved06/17/2020

Related to OsmoBSC - Bug #4832: osmo-bsc hard-releases lchan if no MSC is foundFeedback10/25/2020

History

#1 Updated by neels 4 months ago

  • Related to Feature #2623: SCCP/M3UA: detect restart of osmo-msc and osmo-sgsn added

#2 Updated by neels 4 months ago

  • Related to Bug #4619: ttcn3-bsc-test: all LCLS test cases broken since build #987 added

#3 Updated by neels about 1 month ago

  • Related to Bug #4832: osmo-bsc hard-releases lchan if no MSC is found added

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