When registering many UE’s (with UERANSIM), some are not registered. This is not systematic, but this always happens after some UE’s rebooting. Unregistered UEs are due to unhandled PFCP Session Establishment Request. These requests can be seen in PCAP traces but not UPF’s log.
UERANSIM v3.2.2
[info] UE switches to state [MM-DEREGISTERED/PLMN-SEARCH]
[debug] New signal detected for cell[1], total [1] cells in coverage
[info] Selected cell plmn[208/93] tac[1] category[SUITABLE]
[info] UE switches to state [MM-DEREGISTERED/PS]
[info] UE switches to state [MM-DEREGISTERED/NORMAL-SERVICE]
[debug] Initial registration required due to [MM-DEREG-NORMAL-SERVICE]
[debug] UAC access attempt is allowed for identity[0], category[MO_sig]
[debug] Sending Initial Registration
[info] UE switches to state [MM-REGISTER-INITIATED]
[debug] Sending RRC Setup Request
[info] RRC connection established
[info] UE switches to state [RRC-CONNECTED]
[info] UE switches to state [CM-CONNECTED]
[debug] Authentication Request received
[debug] Sending Authentication Failure due to SQN out of range
[debug] Authentication Request received
[debug] Security Mode Command received
[debug] Selected integrity[2] ciphering[0]
[debug] Registration accept received
[info] UE switches to state [MM-REGISTERED/NORMAL-SERVICE]
[debug] Sending Registration Complete
[info] Initial Registration is successful
[debug] Sending PDU Session Establishment Request
[debug] UAC access attempt is allowed for identity[0], category[MO_sig]
[warning] Retransmitting PDU Session Establishment Request due to T3580 expiry
[debug] UAC access attempt is allowed for identity[0], category[MO_sig]
[warning] Retransmitting PDU Session Establishment Request due to T3580 expiry
[debug] UAC access attempt is allowed for identity[0], category[MO_sig]