Editing My 3GPP 24.501 notes (section)

=== 5.1.3 5GMM sublayer states ===

==== 5.1.3.1 General ====

In the following subclauses, the 5GS mobility management (5GMM) sublayer of the UE and the network is described by means of different state machines. The 5GMM sublayer states is managed per access type independently, i.e. 3GPP access or non-3GPP access. In subclause 5.1.3.2, the states of the 5GMM sublayer are introduced.

===== 5.1.3.2.1 5GMM sublayer states in the UE =====

See spec, lots of info...

===== 5.1.3.2.2	5GS update status in the UE =====

In order to describe the detailed UE behaviour, the 5GS update (5U) status pertaining to a specific subscriber is defined.

If the UE is not operating in SNPN access operation mode (see 3GPP TS 23.501), the 5GS update status is stored in a non-volatile memory in the USIM if the corresponding file is present in the USIM, else in the non-volatile memory in the ME, as described in annex C.

If the UE is operating in SNPN access operation mode, the 5GS update status for each SNPN whose SNPN identity is included in the "list of subscriber data" configured in the ME (see 3GPP TS 23.122) is stored in the non-volatile memory in the ME as described in annex C.

The 5GS update status value is changed only after the execution of a registration, network-initiated de-registration, 5GS based primary authentication and key agreement, service request, paging procedure or due to change in the current TAI which does not belong to the current registration area while T3346 is running.

:5U1: UPDATED
::The last registration attempt was successful.
:5U2: NOT UPDATED
::The last registration or service request attempt failed procedurally, e.g. no response or reject message was received from the AMF.
:5U3: ROAMING NOT ALLOWED
::The last registration, service request, or registration for mobility or periodic registration update attempt was correctly performed, but the answer from the AMF was negative (because of roaming or subscription restrictions).

===== 5.1.3.2.3 5GMM sublayer states in the network side =====

There are four 5GMM sublayer states in the network side.

; 5GMM-DEREGISTERED : In the state 5GMM-DEREGISTERED, no 5GMM context has been established or the 5GMM context is marked as deregistered. The UE is deregistered. The network may answer to an initial registration procedure initiated by the UE. The network may also answer to a de-registration procedure initiated by the UE.
; 5GMM-COMMON-PROCEDURE-INITIATED : The network enters the state 5GMM-COMMON-PROCEDURE-INITIATED, after it has started a common 5GMM procedure and is waiting for a response from the UE.
; 5GMM-REGISTERED : In the state 5GMM-REGISTERED, a 5GMM context has been established. Additionally, one or more PDU session(s) may be established at the network.
; 5GMM-DEREGISTERED-INITIATED : The network enters the state 5GMM-DEREGISTERED-INITIATED after it has started a de-registration procedure and is waiting for a response from the UE.