Attention is currently required from: fixeria, laforge.

lynxis lazus has posted comments on this change by lynxis lazus. ( https://gerrit.osmocom.org/c/osmo-ttcn3-hacks/+/38397?usp=email )

Change subject: SGSN: BSSGP_ConnHdlr: GMM Service Request: handle PMM IDLE UE correct ......................................................................

Patch Set 4:

(1 comment)

File sgsn/BSSGP_ConnHdlr.ttcn:

https://gerrit.osmocom.org/c/osmo-ttcn3-hacks/+/38397/comment/266d95e9_46bf9... : PS4, Line 640: } else {

So in the case of `exp_service_acc := false`, this altstep repeats and will keep waiting for what ki […]

The SGSN (and this testcase) implemented Service Accept in the wrong way.

If a UE wants to transfer data in PMM_IDLE (meaning it is attached, but doesn't has an active channel), the phone will do an Service Request. But the correct flow would be:

(UE/RNC - SGSN) Service Req -> SecurityModeCommand <- SecurityModeCommandComplete ->

There isn't a Service Accept, because it is implicit by the SecurityCommand.

But if the phone is in PMM_CONNECTED, meaning it already has a active signalling channel it would be:

Service Req -> Service Accept <-