6.1.8 Feature Negotiation

29.5183GPP5G SystemAccess and Mobility Management ServicesRelease 16Stage 3TS

The feature negotiation mechanism specified in clause 6.6 of 3GPP TS 29.500 [4] shall be used to negotiate the optional features applicable between the AMF and the NF Service Consumer, for the Namf_Communication service, if any.

The NF Service Consumer shall indicate the optional features it supports for the Namf_Communication service, if any, by including the supportedFeatures attribute in payload of the HTTP Request Message for following service operations:

– N1N2MessgeTransfer, as specified in clause 5.2.2.3.1;

– N1N2MessageSubscribe, as specified in clause 5.2.2.3.3;

– NonUeN2InfoSubscribe, as specified in clause 5.2.2.4.2;

– UeContextTransfer, as specified in clause 5.2.2.2.1;

– CreateUEContext, as specified in clause 5.2.2.2.3

The AMF shall determine the supported features for the service operations as specified in clause 6.6 of 3GPP TS 29.500 [4] and shall indicate the supported features by including the supportedFeatures attribute in payload of the HTTP response for the service operation.

The syntax of the supportedFeatures attribute is defined in clause 5.2.2 of 3GPP TS 29.571 [6].

The following features are defined for the Namf_Communication service.

Table 6.1.8-1: Features of supportedFeatures attribute used by Namf_Communication service

Feature Number

Feature

M/O

Description

1

DTSSA

O

Deployments Topologies with specific SMF Service Areas.

An AMF that supports this feature shall support the procedures specified in clause 5.34 of 3GPP TS 23.501 [2] and in clause 4.23 of 3GPP TS 23.502 [3].

2

ENS

O

This feature bit indicates whether the AMF supports procedures related to Network Slicing (see 3GPP TS 23.501 [2] clause 5.15.7). This includes supporting the RelocateUEContext service operation (see clause 5.2.2.2.5).

3

CIOT

O

Cellular IoT

Support of this feature implies the support of all the CIoT features specified in clause 5.31 of 3GPP TS 23.501 [2], including in particular corresponding service’s extensions to support:

– NB-IoT and LTE-M RAT types;

– Control Plane CIoT 5GS Optimisation;

– Rate control of user data.

4

MAPDU

O

This feature bit indicates whether the AMF supports Multi-Access PDU session procedures related to Access Traffic Steering, Switching and Splitting (see clauses 4.2.10 and 5.32 of 3GPP TS 23.501 [2]).

5

NPN

O

Non-Public Network

Support of this feature implies support of NPN information and receipt of a Create UE context error response with a binary part during an Inter-AMF N2 Handover.

6

ELCS

O

This feature indicates supports of enhanced LCS, including the capability for the AMF to send an LCS message through the target access type requested by the LMF.

7

ES3XX

M

Extended Support of HTTP 307/308 redirection

An NF Service Consumer (e.g. SMF) that supports this feature shall support handling of HTTP 307/308 redirection for any service operation of the Namf_Communication service. An NF Service Consumer that does not support this feature does only support HTTP redirection as specified for 3GPP Release  15.

Feature number: The order number of the feature within the supportedFeatures attribute (starting with 1).

Feature: A short name that can be used to refer to the bit and to the feature.

M/O: Defines if the implementation of the feature is mandatory ("M") or optional ("O").

Description: A clear textual description of the feature.