Cellular Network Infrastructure » Radio Access Network » OsmoPCU

I am currently looking at the packet capture generated by one of the failing testcases:

https://jenkins.osmocom.org/jenkins/view/TTCN3/job/ttcn3-pcu-test/1479/artifact/logs/pcu-tester/PCU_Tests.TC_nacc_outbound_success.pcap.gz

Base Station Subsystem GPRS Protocol
    PDU Type: RAN-INFORMATION-REQUEST (0x71)
    RIM Routing Information - Destination Cell Identifier - RAI: 23-43-423-2, CI 5
        Element ID: 0x54
        1... .... = ext: 1
        Length: 9
        .... 0000 = Routing Address Discriminator: A Cell Identifier is used to identify a GERAN cell (0)
        Routing area identification: 23-43-423-2
            Mobile Country Code (MCC): Unknown (23)
            Mobile Network Code (MNC): Unknown (43)
            Location Area Code (LAC): 0x01a7 (423)
            Routing Area Code (RAC): 0x02 (2)
        CI: 0x0005
    RIM Routing Information - Source Cell Identifier - RAI: 262-42-13135-0, CI 20960
        Element ID: 0x54
        1... .... = ext: 1
        Length: 9
        .... 0000 = Routing Address Discriminator: A Cell Identifier is used to identify a GERAN cell (0)
        Routing area identification: 262-42-13135-0
            Mobile Country Code (MCC): Germany (262)
            Mobile Network Code (MNC): Vodafone GmbH (42)
            Location Area Code (LAC): 0x334f (13135)
            Routing Area Code (RAC): 0x00 (0)
        CI: 0x51e0

This is what the PCU is sending to us, note the Destination Cell Identifier.

IIUC, we had incorrect encoding of the MCC/MNC in both osmo-pcu.git and osmo-ttcn3-hacks.git, so the tests were passing (incorrect expectancies matching incorrect results). Now that we fixed the encoding in osmo-ttcn3-hacks.git, osmo-pcu still generates incorrect results, and thus the tests are failing.

fixeria wrote in #note-1:

IIUC, we had incorrect encoding of the MCC/MNC in both osmo-pcu.git and osmo-ttcn3-hacks.git, so the tests were passing (incorrect expectancies matching incorrect results). Now that we fixed the encoding in osmo-ttcn3-hacks.git, osmo-pcu still generates incorrect results, and thus the tests are failing.

This is not the correct understanding, please ignore this. I was too quick with this assumption. In reality my patch was not entirely correct, so I submitted a partial revert (more details in the commit message):

https://gerrit.osmocom.org/c/osmo-ttcn3-hacks/+/31276 Revert "library/GSM_Types: fix encoding of BcdMccMnc (3 octets)" [NEW]

With this patch applied I got the NACC testcases passing again. I also submitted some additional improvements to the testsuite:

remote: https://gerrit.osmocom.org/c/osmo-ttcn3-hacks/+/31275 pcu/osmo-pcu.cfg: use the PCUIF for neighbor resolution [NEW]
remote: https://gerrit.osmocom.org/c/osmo-ttcn3-hacks/+/31277 library/GSM_Types: rename f_{enc->build}_BcdMccMnc[_int]() [NEW]
remote: https://gerrit.osmocom.org/c/osmo-ttcn3-hacks/+/31278 library/GSM_Types: add {enc,dec}_BcdMccMnc() functions [NEW]
remote: https://gerrit.osmocom.org/c/osmo-ttcn3-hacks/+/31279 PCU_Tests: improve coding style, use f_build_BcdMccMnc() [NEW]
remote: https://gerrit.osmocom.org/c/osmo-ttcn3-hacks/+/31280 PCU_Tests: define ts_BssgpCellIdDstAddr_default [NEW]
remote: https://gerrit.osmocom.org/c/osmo-ttcn3-hacks/+/31281 PCU_Tests: use real values for c_BssgpCell{Mcc,Mnc} [NEW]

Applied in changeset core-testing-infra:osmo-ttcn3-hacks|25cd0dc4c8a38386ac0873ae3a17ffdee8cc7655.