According to TS 23.502, 4.2.2.2.2, AMF sends Registration event to UDM
in the following cases:
- If the AMF has changed since the last Registration procedure, or
- if the UE provides a SUPI which doesn't refer to a valid context in
the AMF,
- or if the UE registers to the same AMF it has already registered
to a non- 3GPP access (i.e. the UE is registered over a non-3GPP access
and initiates this Registration procedure to add a 3GPP access).
In case that UE re-registers to the network with a GUTI, it bypasses
authentication check to the AUSF. In this case, AMF does not send
Registration event to UDM.
Consequently, when UE deregisters again, AMF would send a Deregistration
Event to a UDM, which does not have a context for it.
3GPP standard does not say when AMF sends Deregistration Event to UDM,
only that it is optional.
These (De-)Registration events are for (de-)registering AMF to the UDM
for serving the UE. And not for (de-)registering UE itself for purpose
of tracking when UE is registered on the network.
This partially reverts commit 7be7029ac4
* [SBI] Fix converting PatchItem to JSON
* [UDR] Add support for endpoint for patching subscription data
Add support for PATCH HTTP method for the following endpoint:
/subscription-data/{ueId}/context-data/amf-3gpp-access
Currently does not change any data in the database.
* [UDM] Add support for endpoint for patching subscription data
Add support for the following endpoint, HTTP PATCH method:
/nudm-uecm/v1/{ueId}/registrations/amf-3gpp-access
The endpoint is used when UE deregisters from the core, and AMF
sends a subscription modification request with "purgeFlag" set.
* [UDM] Add check for same GUAMI when patching subscription data
* [AMF] Send deregistration event to UDM
When UE sends deregistration request, AMF needs to send a
Nudm_UECM_Deregistration request to UDM.
The order of requests is now the following:
- send PDU session release to SMF
- send deregistration event to UDM
- send AM policy control release to PCF
During PDU Session Establishment,
if gNB sends PDUSessionResourceReleaseResponse,
AMF was crashed.
In this case, AMF/SMF remove Session Context and sends ErrorIndication.
TS24.501
8.2.11 DL NAS transport
8.2.11.4 5GMM cause
The AMF shall include this IE when the Payload container IE
contains an uplink payload which was not forwarded and
the Payload container type IE is not set to "Multiple payloads".
-0-
As such, this function 'nas_5gs_send_gsm_reject()' must be used
only when an N1 SM message has been forwarded to the SMF.
All process will be forcely exited if it failed to encode the S1AP/NGAP/GTP/PFCP message. It is to make sure there was no problem with the encoding of open5gs.
1. UE sends PDU session establishment request to the AMF.
2. AMF initiates Release Due to Duplicate Session ID.
3. SMF cannot find the session by SM-Context-Ref.
For the above condition, AMF sends NGAP ErrorIndication to the UE.
o Tester
1. UE registered to 5GS and can connect to internet.
2. Turn off the UE and turn on the UE immediately
3. UE send PDU session request message
without sending registration complete
o Analysis Result
1. UE sends registration request with unknown GUTI
2. AMF send registration accept without GUTI
3. UE skips the registration complete
So, we need the handler UL NAS Transport in this state.
Sukchan Lee
Bostjan Meglic
Bostjan Meglic