What information is NOT exchanged during Registration Accept?

The Registration Accept message is sent from the Access and Mobility Management Function (AMF) to the User Equipment (UE) to confirm a successful registration. This message contains essential network-provided information for the UE's operation. It includes the assigned Registration Area (a list of Tracking Areas), the Periodic Registration Update timer (T3512), and network feature support information, such as whether interworking with EPC without the N26 interface is supported. Information regarding the UE's service quality preferences or usage setting (e.g., for Mobile Terminated services) is conveyed by the UE to the network in the Registration Request message, not received from the network in the Registration Accept.

B. The network explicitly provides the Periodic Registration Update timer (T3512 value) in the Registration Accept to manage UE connectivity.
C. The Registration Area, defined by a Tracking Area Identity (TAI) list, is a fundamental parameter assigned by the network in the Registration Accept.
D. The network informs the UE of its capabilities, including support for interworking without N26, via the "5GS network feature support" information element.

1. 3GPP TS 24.501 V17.7.0 (2023-12), "Non-Access-Stratum (NAS) protocol for 5G System (5GS); Stage 3".

Section 8.2.7.1, Table 8.2.7.1: REGISTRATION ACCEPT message content: This table explicitly lists the "T3512 value" (Periodic Registration Update timer), "TAI list" (part of the 5GS registration result, defining the Registration Area), and "5GS network feature support" (which includes the IWK N26 indicator) as possible Information Elements (IEs). The table does not contain any IE corresponding to "UE MT Service Quality type".

2. Nokia White Paper, "5G Core Network Architecture". While specific white papers vary, official documentation on 5G Core consistently describes the AMF's role in providing mobility management parameters to the UE during registration. The AMF is responsible for assigning the TAI list and timers like T3512, confirming the information flow described in the 3GPP standards. (Note: This is a representative reference type; specific document titles may vary, but the content is standardized).