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msc: inter-MSC HO test: use CGI cell ID, not LAI 

Fixes inter-MSC handover tests: in the inter-MSC 'Handover Required', do
not send a LAI cell identifier, but a CGI one.

This is analogous to the fix applied to inter-BSC HO in
I48276acf923626db171683dfa03ef43614a71380.

Rationale:

As explained in OS#5188, 3GPP TS 48.008 allows a LAI identification only
in the Cell Identifier List IE, but not in the single Cell Identifier
IE.

In the inter-MSC HO test's Handover Required message, we so far send a
LAI identifier in a List IE to osmo-msc. And so far, osmo-msc simply
echos that in the Handover Request message's single Cell Id IE.

The LAI is, as actually defined in the spec, omitted from the single IE
in deps/titan.ProtocolModules.BSSMAP/src/BSSAP_Types.ttcn, and when
osmo-msc sends the non-standard LAI Id, ttcn3 fails to parse the BSSMAP
Handover Request message: the Cell Identifier IE gets wrong values, and
all remaining IEs are parsed as 'omit' even though they are present on
the wire. So as long as osmo-msc sends back a LAI Id, we cannot sanely
verify the Handover Request received from the MSC.

The CGI identifier type is supported in both IEs. So when the test sends
a CGI identifier in the Handover Required, osmo-msc will also reflect a
CGI identifier in the Handover Request, and ttcn3 parsing works.

Related: OS#5188 SYS#5324
Change-Id: I525b5deaa9634fcdb63fbd2c97c767aff045767c
This commit is contained in:
Neels Hofmeyr 2021-06-23 03:20:32 +02:00
parent 4b2330474d
commit 36ebc33153
1 changed files with 1 additions and 1 deletions
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msc/MSC_Tests.ttcn
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@ -5985,7 +5985,7 @@ private function f_tc_ho_inter_msc_out(charstring id, BSC_ConnHdlrPars pars) run
var BssmapCause cause := enum2int(cause_val);
var template BSSMAP_FIELD_CellIdentificationList cil;
cil := { cIl_LAI := { ts_BSSMAP_CI_LAI('017'H, '017'H, 1) } };
cil := { cIl_CGI := { ts_BSSMAP_CI_CGI('017'H, '017'H, 1, 1) } };
/* old BSS sends Handover Required */
BSSAP.send(ts_BSSMAP_HandoverRequired(cause, cil));