Feature #6050
closedFeature #5759: Support for Mobility between SGSN (2G/3G) and S-GW (4G)
Add missing testcase to test GERAN originated RIM RAN information request towards a 4G cell (EUTRAN)
20%
Description
At the moment we only have a testcase for an EUTRAN originated RAN information request that targets a GERAN cell (TC_rim_eutran_to_geran). We have no testcase that tests the reverse direction, which is equally important. (We also have no testcase for requests that go from EUTRAN to EUTRAN.)
We should add those two missing testcases to the testsuite in order to be sure that RIM message forwarding is working correctly.
Updated by dexter 11 months ago
- % Done changed from 0 to 20
The testcase I am working on now sends a RAN information request on the GB interface. I can see that the SGSN is forwarding this request towards the Gn interface pointing to the MME. The testcase is also verifying this. The next thing would be to model the response.
Updated by dexter 11 months ago
Unfortunately there seems to be a problem with the idea to retrieve EUTRAN system information from a GERAN. I noticed that there is no way to set the reporting cell identifier in the RAN INFORMATION REQUEST to an EUTRAN cell. (The routing info can be set to EUTRAN cell and the messages get properly routed - no problem here).
After investigating what the problem might be I found the following paragraph in 3GPP TS 48.018 section 8c.6.1:
"In the present specification, NACC between UTRAN and GERAN is restricted to the case of a controlling RNS
and a serving BSS (i.e. assistance is provided for MSs moving from UTRAN to GERAN) and NACC between
E-UTRAN and GERAN is restricted to the case of a controlling eNodeB and a serving BSS (i.e. assistance is
provided for MSs moving from E-UTRAN to GERAN). The reporting cell located in the serving BSS is
therefore always a GERAN cell and shall be addressed as such (RAI + CI) in the NACC application containers."
Apparently this means that there is no way for a PCU to retrieve EUTRAN system information, at least not via RIM. I wonder how this is solved in practice since the PacketCellChangeNotification (see also 3GPP TS 44.060, Table 11.2.3a.1) supports an E-UTRAN Target Cell. This is really confusing. I wonder how this is solved in practice, presumably this is done via SON.
Updated by dexter 10 months ago
This task has become obsolete since we have discovered that there is no RAN INFORMATION REQUEST from GERAN to EUTRAN specified. However, since I already have some code for the testcase we could adapt this so that it tests the generic case of a RIM container passed from GERAN to EUTRAN. This would at least increase the test coverage a bit.
