Cellular Network Infrastructure » Core Network (CN) » OsmoHNBGW

osmo-hnbgw expects a new RUA ctx to start with a RUA procedureCode = Connect.
Instead, while testing with the nano3G, I see a RUA procedureCode DirectTransfer.
osmo-hnbgw reacts to it as expected:

20231204023951411 DCN ERROR unexpected RANAP PDU in RUA Connect message: Direct Transfer (hnbgw_l3.c:313)
20231204023951411 DCN NOTICE Failed to extract Mobile Identity from RUA Connect message's RANAP payload (hnbgw_rua.c:202)
20231204023951411 DCN DEBUG (192.168.2.218:29169 000295-0000154153@ap.ipaccess.com) RUA-23 SCCP-0 PS MI=NONE: NONE NRI(10bit)=0x0=0: No sgsn found for this NRI, doing round-robin (hnbgw_cn.c:1086)

Do we need to allow a DirectTransfer message to initiate a RUA context?

It seems that the particular RUA context retries to do a GMM Attach,
and it seems that it starts out with a procedureCode Connect.
But when that fails, the RNC apparently keeps the RUA context open and re-sends another GMM Attach Request, in a DirectTransfer.

So for this scenario, we should also be able to extract the mobile identity.

In attached pcap iuup_init_fail4.pcapng, see packet 1307.

While capturing the pcap, there was no SGSN running, hence no PS attach can work,
but still the log shows that osmo-hnbgw is not able to handle this situation properly,
even if the SGSN is running to accept IuPS.