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Bug #3844

Gb SNS implementation uses pre-configured IP/port even if it is not part of the SNS-CONFIG

Added by laforge 9 months ago. Updated 5 months ago.

Status:
Resolved
Priority:
High
Assignee:
Target version:
-
Start date:
03/16/2019
Due date:
% Done:

100%

Spec Reference:

Description

Section 6.2.1 of 3GPP TS 48.016 states:

A pre-configured endpoint shall not be used for NSE data or signalling traffic (with the exception of Size and Configuration procedures) unless it is configured by the SGSN using the auto-configuration procedures.

However, in the current SNS implementation, the initial IP/Port over which we perform the SNS-SIZE + SNS-CONFIG are treated as one of the normal NS-VCs. Specifically, we also perform the NS-ALIVE procedure on it, which is clearly wrong.

History

#1 Updated by laforge 9 months ago

Patch is now in review: https://gerrit.osmocom.org/#/c/libosmocore/+/13291

A test case has been developed in https://gerrit.osmocom.org/#/c/osmo-ttcn3-hacks/+/13292

The pcap file in the attachment shows success:

  • the initial connection to the SGSN (port 23000) is used for SNS procedures
  • the SNS-CONFIG negotiates only ports 23001 and 23002 shall be used
  • NS-ALIVE from PCU are seen to 23001 + 23002 but not to 23000
  • If the simulated SGSN should send anything (like an NS-ALIVE) from 23000 to the PCU, the PCU will reject it with NS-STATUS

#2 Updated by laforge 5 months ago

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

patches were merged months ago, just this ticket was not closed

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