2nd UE PDU Session fails: "CreateSmContextRequest Error: undefined response type" (v3.4.3)

Q/A
1

Running free5GC v3.4.3 + UERANSIM v3.2.8, core and RAN on separate hosts.

Issue: First UE registers and establishes a PDU session successfully every time. Any additional UE — provisioned by cloning the first UE’s subscriber data across all relevant MongoDB collections (authenticationSubscription, amData, smData, smfSelectionSubscriptionData, identityData, policyData.ues.*, subscribers) — registers fine, but PDU Session Establishment never gets a response. UERANSIM retries via T3580 5x then fails permanently.

AMF log at failure point:

getSmDataProcedure: SUPI[imsi-…] …
Allocated PDUAdress[…]
CreateSmContextRequest Error: undefined response type

UE-side log: retries 5x via T3580, then PDU Session Establishment procedure failure, no response from the network after 5 attempts → Aborting SM procedure.

Already ruled out: cloned subscriber data is byte-identical to the working UE (checked across 4 collections), full reboots don’t change the outcome, staggered/non-overlapping UE startup timing doesn’t change the outcome, OAuth on/off in nrfcfg.yaml makes no difference.

  1. free5GC version: v3.4.3
  2. OS: Ubuntu 22.04.5 LTS
  3. gtp5g: installed, loaded
  4. Native, ARM aarch64
  5. Kernel: 5.15.0-1102
2

IMSI must be unique per UE. If you simply cloned every data structure, the resulting database would contain duplicated IMSI etc, causing errors when the UEs start.

Please see these lines in my integration script for reference: