Cellular Network Infrastructure » Core Network (CN) » OsmoMSC

I'll try to implement some basic test coverage.

As I understand, we need to emulate the following:

• subscribers, sending and receiving USSDs at the same time (according to 3GPP TS 04.80);
• TTCN-3 based external USSD gateway (as soon as I finish the GSUP interface);
  • network initiated USSD-sessions;
  • subscriber initiated USSD-sessions;
  • error cases during USSD-sessions (e.g. losing connection with USSD gateway);
  • multiple USSD-sessions with a single subscriber (on both MM and transaction levels);

The current plan of this work is:

1. (DONE) Implement abstract functions for GSM 04.80 coding
2. (DONE) TC: single request with known code (`*#100#`)
3. (DONE) TC: single request with unknown code (`*#999#`)
4. (DONE) TC: USSD request during an active call
5. TC: invalid initial request with DCS != 0x0f
6. TC: network originated USSD notification
7. Multiple requests within a session:
7.1. Emulate the USSD GW on the HLR side
7.2. TC: REQ_MS, REQ_NET, RSP_MS, RSP_NET
7.3. TC: MS initiated RELEASE_COMPLETE

Patches for both 1. and 2. have been sent to review:

https://gerrit.osmocom.org/#/q/status:open+project:osmo-ttcn3-hacks+topic:ussd
https://gerrit.osmocom.org/#/c/osmo-ttcn3-hacks/+/9372/

Two new testcases have been submitted:

TC: single request with unknown code (`*#999#`)
https://gerrit.osmocom.org/9470/

TC: USSD request during an active call:
https://gerrit.osmocom.org/9471/

As we are about to finish the GSM 09.11 implementation, i.e. 'SS/USSD over GSUP' in our case,
the existing test cases were updated in order to expect and reply GSUP messages:

https://gerrit.osmocom.org/9685/

Also, a new tests cases for network-initiated transactions have been sent to review:

https://gerrit.osmocom.org/9686/

Finally, the test case, which was intended to check the reaction on unknown USSD-code, is going to be dropped:

https://gerrit.osmocom.org/9683/

Future plans:

• Test case for MS-initiated RELEASE
• Test case for a few concurrent SS/USSD transactions
• Test cases for abnormal cases, e.g.
  • referencing a non-existing transaction
  • interrupting an active transaction
  • no response to Paging Request

Regarding the inactivity timeout, please see https://gerrit.osmocom.org/#/c/osmo-ttcn3-hacks/+/11985/

https://gerrit.osmocom.org/c/osmo-ttcn3-hacks/+/14450 MSC_Tests.ttcn: introduce TC_mt_ussd_for_unknown_subscr

https://gerrit.osmocom.org/c/osmo-ttcn3-hacks/+/14460 MSC_Tests.ttcn: introduce TC_proc_ss_for_unknown_session
https://gerrit.osmocom.org/c/osmo-ttcn3-hacks/+/14503 MSC_Tests.ttcn: introduce TC_mo_ussd_for_unknown_trans

https://gerrit.osmocom.org/c/osmo-ttcn3-hacks/+/14474 MSC_Tests.ttcn: introduce TC_proc_ss_paging_fail
https://gerrit.osmocom.org/c/osmo-msc/+/14475 libmsc/gsm_09_11.c: inform HLR/EUSE if Paging has failed

https://gerrit.osmocom.org/c/osmo-ttcn3-hacks/+/14476 MSC_Tests.ttcn: introduce TC_proc_ss_abort

[ ] Test case for a few concurrent SS/USSD transactions

I guess I will need to implement a TTCN-3 component for that, as we do in the HLR_Tests.ttcn.

See https://gerrit.osmocom.org/r/I2fb1c5d285163d5245d92fa24c197a5027ecbe6f MSC: add test cases for concurrent MO/MT SS/USSD transactions