Content for TS 23.501 Word version: 19.1.0

1… 3… 4.2.3 4.2.4 4.2.5… 4.2.8… 4.2.8.2.2 4.2.8.2.3… 4.2.8.4… 4.2.9… 4.2.15… 4.3… 4.3.3 4.3.4 4.3.5 4.4… 4.4.6… 4.4.8… 5… 5.3… 5.3.3… 5.4… 5.5… 5.6… 5.6.7… 5.7… 5.7.2… 5.7.3… 5.7.4 5.7.5… 5.8… 5.8.2.11… 5.9… 5.10… 5.11… 5.15… 5.15.11… 5.16… 5.17… 5.18… 5.19… 5.21… 5.22… 5.27… 5.28… 5.29… 5.30… 5.31… 5.32… 5.32.6… 5.33… 5.34… 5.35… 5.38… 5.43… 5.49… 6… 6.3… 6.3.8… 7… 7.2… 8… 8.2.4 8.2.5… 8.3… A… D… E… F G… G.3 G.4… H… J K… M… N… O… P… S…

3.1 Definitions 3.2 Abbreviations 4.1 General concepts 4.2 Architecture reference model 4.2.1 General 4.2.2 Network Functions and entities
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3 Definitions and abbreviations p. 30

3.1 Definitions p. 30

For the purposes of the present document, the terms and definitions given in TR 21.905 and the following apply. A term defined in the present document takes precedence over the definition of the same term, if any, in TR 21.905.

5G VN Group:

A set of UEs using private communication for 5G LAN-type service.

5G Access Network:

An access network comprising a NG-RAN and/or non-3GPP AN connecting to a 5G Core Network.

5G Access Stratum-based Time Distribution:

A time synchronization distribution method that is used by an NG-RAN to provide the 5GS time to the UE(s) over the radio interface using procedures specified in TS 38.331.

5G Core Network:

The core network specified in the present document. It connects to a 5G Access Network.

5G LAN-Type Service:

A service over the 5G system offering private communication using IP and/or non-IP type communications.

5G LAN-Virtual Network:

A virtual network over the 5G system capable of supporting 5G LAN-type service.

5G NSWO:

The 5G NSWO is the capability provided by 5G system and by UE to enable the connection to a WLAN access network using 5GS credentials without registration to 5GS.

5G QoS Flow or QoS Flow:

The finest granularity for QoS forwarding treatment in the 5G System. All traffic mapped to the same 5G QoS Flow receive the same forwarding treatment (e.g. scheduling policy, queue management policy, rate shaping policy, RLC configuration, etc.). Providing different QoS forwarding treatment requires separate 5G QoS Flow.

5G QoS Identifier:

A scalar that is used as a reference to a specific QoS forwarding behaviour (e.g. packet loss rate, packet delay budget) to be provided to a 5G QoS Flow. This may be implemented in the access network by the 5QI referencing node specific parameters that control the QoS forwarding treatment (e.g. scheduling weights, admission thresholds, queue management thresholds, link layer protocol configuration, etc.).

5G System:

3GPP system consisting of 5G Access Network (AN), 5G Core Network and UE.

5G-BRG:

The 5G-BRG is a 5G-RG defined in BBF.

5G-CRG:

The 5G-CRG is a 5G-RG specified in DOCSIS MULPI [89].

5G-RG:

A 5G-RG is a RG capable of connecting to 5GC playing the role of a UE with regard to the 5G core. It supports secure element and exchanges N1 signalling with 5GC. The 5G-RG can be either a 5G-BRG or 5G-CRG.

Access Traffic Steering:

The procedure that selects an access network for a new data flow and transfers the traffic of this data flow over the selected access network. Access traffic steering is applicable between one 3GPP access and one non-3GPP access.

Access Traffic Switching:

The procedure that moves all traffic of an ongoing data flow from one access network to another access network in a way that maintains the continuity of the data flow. Access traffic switching is applicable between one 3GPP access and one non-3GPP access.

Access Traffic Splitting:

The procedure that splits the traffic of a data flow across multiple access networks. When traffic splitting is applied to a data flow, some traffic of the data flow is transferred via one access and some other traffic of the same data flow is transferred via another access. Access traffic splitting is applicable between one 3GPP access and one non-3GPP access.

Allowed NSSAI:

Indicating the S-NSSAIs values the UE could use in the Serving PLMN in the current Registration Area.

Allowed Area:

Area where the UE is allowed to initiate communication as specified in clause 5.3.2.3.

Alternative S-NSSAI:

Indicating a compatible S-NSSAI for an S-NSSAI in the Allowed NSSAI that the AMF uses to replace an S-NSSAI when the S-NSSAI is not available or congested, as specified in clause 5.15.19.

AMF Region:

An AMF Region consists of one or multiple AMF Sets.

AMF Set:

An AMF Set consists of some AMFs that serve a given area and Network Slice(s). AMF Set is unique within an AMF Region and it comprises of AMFs that support the same Network Slice(s). Multiple AMF Sets may be defined per AMF Region. The AMF instances in the same AMF Set may be geographically distributed but have access to the same context data.

Application Identifier:

An identifier that can be mapped to a specific application traffic detection rule.

AUSF Group ID:

This refers to one or more AUSF instances managing a specific set of SUPIs. An AUSF Group consists of one or multiple AUSF Sets.

Backhaul PLMN/SNPN (BH PLMN/SNPN):

The PLMN or SNPN serving a MWAB-UE. It can be a Terrestrial Network or a Non-Terrestrial Network.

Binding Indication:

Information included by a NF service producer to a NF service consumer in request responses or notifications to convey the scope within which selection/reselection of target NF/NF Services may be performed, or information included by the NF service consumer in requests or subscriptions to convey the scope within which selection/reselection of notification targets or the selection of other service(s) that the NF consumer produces for the same data context may be performed. See clause 6.3.1.0.

BSF Group ID:

This refers to one or more BSF instances managing a specific set of SUPIs or GPSIs. A BSF Group consists of one or multiple BSF Sets.

Configured NSSAI:

NSSAI provisioned in the UE applicable to one or more PLMNs.

CHF Group ID:

This refers to one or more CHF instances managing a specific set of SUPIs.

Credentials Holder:

Entity which authenticates and authorizes access to an SNPN separate from the Credentials Holder.

Default UE credentials:

Information configured in the UE to make the UE uniquely identifiable and verifiably secure to perform UE onboarding.

Data Burst:

A set of multiple PDUs generated and sent by the application in a short period of time.

Default Credentials Server (DCS):

An entity that can perform authentication based on the Default UE credentials or provide means for another entity to perform authentication based on the Default UE credentials.

Delegated Discovery:

This refers to delegating the discovery and associated selection of NF instances or NF service instances to an SCP.

Direct Communication:

This refers to the communication between NFs or NF services without using an SCP.

Disaster Condition:

See definition in TS 22.261.

Disaster Inbound Roamer:

See definition in TS 22.261.

Disaster Roaming:

See definition in TS 22.261.

DN Access Identifier (DNAI):

Identifier of a user plane access to one or more DN(s) where applications are deployed.

Emergency Registered:

A UE is considered Emergency Registered over an Access Type in a PLMN when registered for emergency services only over this Access Type in this PLMN.

Endpoint Address:

An address in the format of an IP address or FQDN, which is used to determine the host/authority part of the target URI. This Target URI is used to access an NF service (i.e. to invoke service operations) of an NF service producer or for notifications to an NF service consumer.

En-gNB:

as defined in TS 37.340.

Expected UE Behaviour:

Set of parameters provisioned by an external party to 5G network functions on the foreseen or expected UE behaviour, see clause 5.20.

Feeder link:

As defined in TS 38.300.

Fixed Network Residential Gateway:

A Fixed Network RG (FN-RG) is a RG that it does not support N1 signalling and it is not 5GC capable.

Fixed Network Broadband Residential Gateway:

A Fixed Network RG (FN-BRG) is a FN-RG specified in BBF TR-124 [90].

Fixed Network Cable Residential Gateway:

A Fixed Network Cable RG (FN-CRG) is a FN-RG with cable modem specified in DOCSIS MULPI [89].

Forbidden Area:

An area where the UE is not allowed to initiate communication as specified in clause 5.3.2.3.

GBR QoS Flow:

A QoS Flow using the GBR resource type or the Delay-critical GBR resource type and requiring guaranteed flow bit rate.

Group ID for Network Selection (GIN):

An identifier used during SNPN selection to enhance the likelihood of selecting a preferred SNPN that supports a Default Credentials Server or a Credentials Holder.

(g)PTP-based Time Distribution:

a method to distribute timing among entities in a (g)PTP domain using PTP messages generated by a GM (in the case the GM is external to 5GS) or by 5GS (in the case the 5GS acts as a GM for a given (g)PTP domain). Possible dependencies between (g)PTP-based Time Distribution and 5G Access Stratum-based Time Distribution are described in clause 5.27.1. The synchronization process is described in clause 5.27.1 and follows the applicable profiles of IEEE Std 802.1AS [104] or IEEE Std 1588 [126].

Home Network Public Key Identifier:

An identifier used to indicate which public/private key pair is used for SUPI protection and de-concealment of the SUCI as specified in TS 23.003.

IAB-donor:

This is a NG-RAN node that supports Integrated access and backhaul (IAB) feature and provides connection to the core network to IAB-nodes. It supports the CU function of the CU/DU architecture for IAB defined in TS 38.401.

IAB-node:

A relay node that supports wireless in-band and out-of-band relaying of NR access traffic via NR Uu backhaul links. It supports the UE function and the DU function of the CU/DU architecture for IAB defined in TS 38.401.

Indirect Communication:

This refers to the communication between NFs or NF services via an SCP.

Initial Registration:

UE registration in RM-DEREGISTERED state as specified in clause 5.3.2.

Intermediate SMF (I-SMF):

An SMF that is inserted to support a PDU session as the UE is located in an area which cannot be controlled by the original SMF because the UPF(s) belong to a different SMF Service Area.

Local Area Data Network:

a DN that is accessible by the UE only in specific locations, that provides connectivity to a specific DNN, and whose availability is provided to the UE.

Local Break Out (LBO):

Roaming scenario for a PDU Session where the PDU Session Anchor and its controlling SMF are located in the serving PLMN (VPLMN).

LTE-M:

a 3GPP RAT type Identifier used in the Core Network only, which is a sub-type of E-UTRA RAT type, and defined to identify in the Core Network the E-UTRA when used by a UE indicating Category M.

MA PDU Session:

A PDU Session that provides a PDU connectivity service, which can use one access network at a time, or simultaneously one 3GPP access network and one non-3GPP access network.

Mobile Base Station Relay:

A mobile base station acts as a relay between a UE and the 5G network. Such mobile base station relay can for example be mounted on a moving vehicle and serve UEs that can be located inside or outside the vehicle (or entering/leaving the vehicle). See description of TS 22.261. A mobile Base Station Relay is supported in 5GS with the IAB-architecture with mobility as specified in clause 5.35A and that described in TS 38.401.

Mobile gNB with Wireless Access Backhauling (MWAB):

A NG-RAN device comprised of a UE (MWAB-UE) and a gNB (MWAB-gNB). The MWAB provides an NR access link to UEs and connects wirelessly to the 5GC (using NR) of a PLMN or SNPN broadcasted by its cell(s), through an IP connectivity provided by a Backhaul (BH) PDU sessions established by the MWAB-UE via the NG-RAN of a Backhaul(BH) PLMN/SNPN. Such device may be mobile, e.g. it may be mounted on a moving vehicle and serve UEs that can be located inside or outside the vehicle (or entering/leaving the vehicle).

MWAB Broadcasted PLMN/SNPN:

A PLMN or SNPN whose identifier a MWAB-gNB cell(s) is(are) configured to broadcast in the system information. This is a PLMN/SNPN the MWAB-gNB provides access to.

Master RAN node:

A Master node as defined in TS 37.340.

Mobility Pattern:

Network concept of determining within the AMF the UE mobility parameters as specified in clause 5.3.2.4.

Mobility Registration Update:

UE re-registration when entering new TA outside the TAI List as specified in clause 5.3.2.

MPS-subscribed UE:

A UE having a USIM with MPS subscription.

Multi-USIM UE:

A UE with multiple USIMs, capable of maintaining a separate registration state with a PLMN for each USIM at least over 3GPP Access and supporting one or more of the features described in clause 5.38.

NB-IoT UE Priority:

Numerical value used by the NG-RAN to prioritise between different UEs accessing via NB-IoT.

NGAP UE association:

The logical per UE association between a 5G-AN node and an AMF.

NGAP UE-TNLA-binding:

The binding between a NGAP UE association and a specific TNL association for a given UE.

Network Function:

A 3GPP adopted or 3GPP defined processing function in a network, which has defined functional behaviour and 3GPP defined interfaces.

Network Instance:

Information identifying a domain. Used by the UPF for traffic detection and routing.

Network Slice:

A logical network that provides specific network capabilities and network characteristics.

Network Slice Area of Service (NS-AoS):

The area where a network slice is available i.e. the UE can access and get service of a particular network slice as more than zero resources are allocated to the network slice in the NG-RAN cells. This area may be, depending on the specific network slice, the whole PLMN, one or more TAs, or one or more cells when the NS-AoS does not match deployed TAs as defined in clause 5.15.18.

Network Slice instance:

A set of Network Function instances and the required resources (e.g. compute, storage and networking resources) which form a deployed Network Slice.

Non-GBR QoS Flow:

A QoS Flow using the Non-GBR resource type and not requiring guaranteed flow bit rate.

NSI ID:

an identifier for identifying the Core Network part of a Network Slice instance when multiple Network Slice instances of the same Network Slice are deployed, and there is a need to differentiate between them in the 5GC.

NF instance:

an identifiable instance of the NF.

NF service:

a functionality exposed by a NF through a service based interface and consumed by other authorized NFs.

NF service instance:

an identifiable instance of the NF service.

NF service operation:

An elementary unit a NF service is composed of.

NF Service Set:

A group of interchangeable NF service instances of the same service type within an NF instance. The NF service instances in the same NF Service Set have access to the same context data.

NF Set:

A group of interchangeable NF instances of the same type, supporting the same services and the same Network Slice(s). The NF instances in the same NF Set may be geographically distributed but have access to the same context data.

NG-RAN:

A radio access network that supports one or more of the following options with the common characteristics that it connects to 5GC:

Standalone New Radio.
New Radio is the anchor with E-UTRA extensions.
Standalone E-UTRA.
E-UTRA is the anchor with New Radio extensions.

Non-3GPP QoS Assistance Information:

A set of QoS assistance information provided to the UE (e.g. PEGC) to enable the UE to perform QoS differentiation for the connected devices in the non-3GPP network behind the UE.

Non-Allowed Area:

Area where the UE is allowed to initiate Registration procedure but no other communication as specified in clause 5.3.2.3.

Non-Public Network:

See definition in TS 22.261.

Non-Seamless Non-3GPP offload:

The offload of user plane traffic via non-3GPP access without traversing either N3IWF/TNGF or UPF.

Non-Seamless WLAN offload:

Non-Seamless Non-3GPP offload when the non-3GPP access network is WLAN.

Onboarding Network:

Either a PLMN enabling Remote Provisioning for a registered UE, or an Onboarding SNPN.

Onboarding Standalone Non-Public Network:

An SNPN providing Onboarding access and enabling Remote Provisioning for a UE registered for Onboarding as specified in clause 4.2.2.2.4 of TS 23.502.

Partially Allowed NSSAI:

Indicating the S-NSSAIs values the UE could use in the Serving PLMN or SNPN in some of the TAs in the current Registration Area. Each S-NSSAI in the Partially Allowed NSSAI is associated with a list of TAs where the S-NSSAI is supported.

PCF Group ID:

This refers to one or more PCF instances managing a specific set of SUPIs. A PCF Group consists of one or multiple PCF Sets.

PDU Connectivity Service:

A service that provides exchange of PDUs between a UE and a Data Network.

PDU Session:

Association between the UE and a Data Network that provides a PDU connectivity service.

PDU Session Type:

The type of PDU Session which can be IPv4, IPv6, IPv4v6, Ethernet or Unstructured.

PDU Set:

One or more PDUs carrying the payload of one unit of information generated at the application level (e.g. frame(s) or video slice(s) etc. for eXtended Reality (XR) Services). All the PDUs of a PDU set are transmitted within the same QoS Flow.

Pending NSSAI:

NSSAI provided by the Serving PLMN during a Registration procedure, indicating the S-NSSAI(s) for which the network slice-specific authentication and authorization procedure is pending.

Periodic Registration Update:

UE re-registration at expiry of periodic registration timer as specified in clause 5.3.2.

Personal IoT Network (PIN):

A network with group of elements (i.e. UE or non-3GPP device) that are able to communicate with each other directly, communicate with each other via intermediate element(s), communicate with each other via 5GS, or communicate with external DN via 5GS.

PIN Element (PINE):

A UE or non-3GPP device that is part of the group of elements in a PIN.

PIN Element with Gateway Capability (PEGC):

A PINE with the ability to provide DN connectivity via the 5G network for other PINEs and/or a PINE with the ability to provide relay functionality for communication between PINEs. Only a UE is able to act as a PEGC. A PIN includes at least one PEGC.

PIN Element with Management Capability (PEMC):

A PINE with capability to manage the PIN and the management is supported by an AF if deployed. A PIN includes at least one PEMC.

PIN management traffic:

The traffic among PINE, PEGC, PEMC and AF for PIN related to the management of PIN.

PIN-DN communication:

The communication between PINE and DN via a PEGC and 5G network, as well as the communication between PEGC and DN via 5G network. The communication includes both the data traffic and the PIN management traffic (e.g. the data traffic towards the internet or the PIN management traffic towards the AF for PIN).

PIN direct communication:

The communication without traversing 5G network between two PINEs (e.g. between a PINE and a PEGC, between a PINE and a PEMC, between a PEMC and a PEGC and between two PEGCs). The communication traverses intermediate PINE(s) or not. The communication includes both the data traffic and the PIN management traffic (e.g. the data traffic between 2 PINEs or the PIN management traffic between PINE and PEMC).

PIN indirect communication:

The communication with traversing 5G network between PINEs connected to different PEGCs of the same PIN, and between a PINE and a PEMC via PEGC and 5G network. The communication includes both the data traffic and the PIN management traffic (e.g. the data traffic between 2 PINEs or the PIN management traffic between PINE and PEMC).

PLMN with Disaster Condition:

A PLMN to which a Disaster Condition applies.

Pre-configured 5QI:

Pre-defined QoS characteristics configured in the AN and 5GC and referenced via a non-standardized 5QI value. Corresponding to Operator-specific 5QI in TS 24.501.

Primary cell:

as defined in TS 36.331.

Primary RAT:

RAT of the Master RAN node, when Dual Connectivity is used; otherwise RAT of the RAN node.

Private communication:

See definition in TS 22.261.

Provisioning Server:

Entity that provisions network credentials and other data in the UE to enable SNPN access.

PTP domain:

As defined in IEEE Std 1588 [126].

Public network integrated NPN:

A non-public network deployed with the support of a PLMN.

(Radio) Access Network:

See 5G Access Network.

RAT type:

Identifies the transmission technology used in the access network for both 3GPP accesses and non-3GPP Accesses, for example, NR, NB-IOT, Untrusted Non-3GPP, Trusted Non-3GPP, Trusted IEEE 802.11 Non-3GPP access, Wireline, Wireline-Cable, Wireline-BBF, etc.

NR RedCap:

a 3GPP RAT type Identifier used in the Core Network only, which is a sub-type of NR RAT type, and defined to identify in the Core Network the NR when used by a UE indicating NR RedCap.

NR eRedCap:

a 3GPP RAT type Identifier used in the Core Network only, which is a sub-type of NR RAT type, and defined to identify in the Core Network the NR when used by a UE indicating NR eRedCap.

Requested NSSAI:

NSSAI provided by the UE to the Serving PLMN during registration.

Residential Gateway:

The Residential Gateway (RG) is a device providing, for example voice, data, broadcast video, video on demand, to other devices in customer premises.

Routing Binding Indication:

Information included in a request or notification and that can be used by the SCP for discovery and associated selection to of a suitable target. See clauses 6.3.1.0 and 7.1.2

Routing Indicator:

Indicator that allows together with SUCI/SUPI Home Network Identifier to route network signalling to AUSF and UDM instances capable to serve the subscriber.

RRC_IDLE, RRC_CONNECTED, RRC_INACTIVE:

As defined in TS 38.331 and TS 38.306.

SCP Domain:

A configured group of one or more SCP(s) and zero or more NF instances(s). An SCP within the group can communicate with any NF instance or SCP within the same group directly, i.e. without passing through an intermediate SCP.

Secondary RAN node:

A Secondary node as defined in TS 37.340.

Secondary RAT:

RAT of the secondary RAN node.

Service link:

As defined in TS 38.300.

SNPN-enabled UE:

A UE configured to use stand-alone Non-Public Networks.

SNPN access mode:

A UE operating in SNPN access mode only selects stand-alone Non-Public Networks over Uu, Yt, NWu.

Service based interface:

It represents how a set of services is provided/exposed by a given NF.

Service Continuity:

The uninterrupted user experience of a service, including the cases where the IP address and/or anchoring point change.

Service Data Flow Filter:

A set of packet flow header parameter values/ranges used to identify one or more of the (IP or Ethernet) packet flows constituting a Service Data Flow.

Service Data Flow Template:

The set of Service Data Flow filters in a policy rule or an application identifier in a policy rule referring to an application detection filter, required for defining a Service Data Flow.

Session Continuity:

The continuity of a PDU Session. For PDU Session of IPv4 or IPv6 or IPv4v6 type "session continuity" implies that the IP address is preserved for the lifetime of the PDU Session.

SMF Service Area:

The collection of UPF Service Areas of all UPFs which can be controlled by one SMF.

SNPN ID:

PLMN ID and NID identifying an SNPN.

Stand-alone Non-Public Network:

A non-public network not relying on network functions provided by a PLMN

Subscribed S-NSSAI:

S-NSSAI based on subscriber information, which a UE is subscribed to use in a PLMN

Subscription Owner Standalone Non-Public Network:

A Standalone Non-Public Network owning the subscription of a UE and providing subscription data to the UE via a Provisioning Server during the onboarding procedure.

Survival Time:

The time that an application consuming a communication service may continue without an anticipated message.

Target NSSAI:

NSSAI provided by the Serving PLMN to the NG-RAN to cause the NG-RAN to attempt to steer the UE to a cell supporting the Network Slices identified by the S-NSSAIs in this NSSAI. See clause 5.3.4.3.3 for more details.

Time Sensitive Communication (TSC):

A communication service that supports deterministic communication (i.e. which ensures a maximum delay) and/or isochronous communication with high reliability and availability. It is about providing packet transport with QoS characteristics such as bounds on latency, loss, and reliability, where end systems and relay/transmit nodes may or may not be strictly synchronized.

TSN working domain:

Synchronization domain for a localized set of devices collaborating on a specific task or work function in a TSN network, corresponding to a gPTP domain defined in IEEE 802.1AS [104].

UDM Group ID:

This refers to one or more UDM instances managing a specific set of SUPIs. An UDM Group consists of one or multiple UDM Sets.

UDR Group ID:

This refers to one or more UDR instances managing a specific set of SUPIs. An UDR Group consists of one or multiple UDR Sets.

UE-DS-TT Residence Time:

The time taken within the UE and DS-TT to forward a packet, i.e. between the ingress of the UE and the DS-TT port in the DL direction, or between the DS-TT port and the egress of the UE in the UL direction. UE-DS-TT Residence Time is provided at the time of PDU Session Establishment by the UE to the network.

UPF Service Area:

An area consisting of one or more TA(s) within which PDU Session associated with the UPF can be served by (R)AN nodes via a N3 interface between the (R)AN and the UPF without need to add a new UPF in between or to remove/re-allocate the UPF.

Uplink Classifier:

UPF functionality that aims at diverting Uplink traffic, based on filter rules provided by SMF, towards Data Network.

WB-E-UTRA:

In the RAN, WB-E-UTRA is the part of E-UTRA that excludes NB-IoT. In the Core Network, WB-E-UTRA also excludes LTE-M.

Wireline 5G Access Network:

The Wireline 5G Access Network (W-5GAN) is a wireline AN that connects to a 5GC via N2 and N3 reference points. The W-5GAN can be either a W-5GBAN or W-5GCAN.

Wireline 5G Cable Access Network:

The Wireline 5G Cable Access Network (W-5GCAN) is the Access Network defined in CableLabs.

Wireline BBF Access Network:

The Wireline 5G BBF Access Network (W-5GBAN) is the Access Network defined in BBF.

Wireline Access Gateway Function (W-AGF):

The Wireline Access Gateway Function (W-AGF) is a Network function in W-5GAN that provides connectivity to the 5G Core to 5G-RG and FN-RG.

3.2 Abbreviations p. 37

For the purposes of the present document, the abbreviations given in TR 21.905 and the following apply. An abbreviation defined in the present document takes precedence over the definition of the same abbreviation, if any, in TR 21.905.

5GC

5G Core Network

5G DDNMF

5G Direct Discovery Name Management Function

5G LAN

5G Local Area Network

5GS

5G System

5G-AN

5G Access Network

5G-AN PDB

5G Access Network Packet Delay Budget

5G-EIR

5G-Equipment Identity Register

5G-GUTI

5G Globally Unique Temporary Identifier

5G-BRG

5G Broadband Residential Gateway

5G-CRG

5G Cable Residential Gateway

5G GM

5G Grand Master

5G NSWO

5G Non-Seamless WLAN offload

5G-RG

5G Residential Gateway

5G-S-TMSI

5G S-Temporary Mobile Subscription Identifier

5G VN

5G Virtual Network

5QI

5G QoS Identifier

ADRF

Analytics Data Repository Function

Application Function

AI/ML

Artificial Intelligence/Machine Learning

AKMA

Authentication and Key Management for Applications

AnLF

Analytics Logical Function

AMF

Access and Mobility Management Function

AoI

Area of Interest

Access Stratum

ATSSS

Access Traffic Steering, Switching, Splitting

ATSSS-LL

ATSSS Low-Layer

AUSF

Authentication Server Function

BMCA

Best Master Clock Algorithm

BSF

Binding Support Function

CAG

Closed Access Group

CAPIF

Common API Framework for 3GPP northbound APIs

Credentials Holder

CHF

Charging Function

CN PDB

Core Network Packet Delay Budget

Control Plane

CQRCI

Clock Quality Reporting Control Information

DAPS

Dual Active Protocol Stacks

DCCF

Data Collection Coordination Function

DCS

Default Credentials Server

DetNet

Deterministic Networking

Downlink

Data Network

DNAI

DN Access Identifier

DNN

Data Network Name

DRX

Discontinuous Reception

DS-TT

Device-side TSN translator

EAC

Early Admission Control

ePDG

evolved Packet Data Gateway

EBI

EPS Bearer Identity

EUI

Extended Unique Identifier

FAR

Forwarding Action Rule

Federated Learning

FN-BRG

Fixed Network Broadband RG

FN-CRG

Fixed Network Cable RG

FN-RG

Fixed Network RG

FQDN

Fully Qualified Domain Name

GBA

Generic Bootstrapping Architecture

GEO

Geostationary Orbit

GFBR

Guaranteed Flow Bit Rate

GIN

Group ID for Network Selection

GMLC

Gateway Mobile Location Centre

GPSI

Generic Public Subscription Identifier

GUAMI

Globally Unique AMF Identifier

HMTC

High-Performance Machine-Type Communications

Home Routed (roaming)

IAB

Integrated access and backhaul

IMEI/TAC

IMEI Type Allocation Code

IPUPS

Inter PLMN UP Security

I-SMF

Intermediate SMF

I-UPF

Intermediate UPF

LADN

Local Area Data Network

LBO

Local Break Out (roaming)

LEO

Low Earth Orbit

LMF

Location Management Function

LoA

Level of Automation

LPP

LTE Positioning Protocol

LRF

Location Retrieval Function

L4S

Low Latency, Low Loss and Scalable Throughput

MBS

Multicast/Broadcast Service

MBSF

Multicast/Broadcast Service Function

MBSR

Mobile Base Station Relay

MBSTF

Multicast/Broadcast Service Transport Function

MB-SMF

Multicast/Broadcast Session Management Function

MB-UPF

Multicast/Broadcast User Plane Function

MEO

Medium Earth Orbit

MFAF

Messaging Framework Adaptor Function

MCX

Mission Critical Service

MDBV

Maximum Data Burst Volume

MFBR

Maximum Flow Bit Rate

MICO

Mobile Initiated Connection Only

MINT

Minimization of Service Interruption

Machine Learning

MPQUIC

Multi-Path QUIC

MPS

Multimedia Priority Service

MPTCP

Multi-Path TCP Protocol

MTLF

Model Training Logical Function

MWAB

Mobile gNB with wireless access backhauling

N3IWF

Non-3GPP InterWorking Function

N3QAI

Non-3GPP QoS Assistance Information

N5CW

Non-5G-Capable over WLAN

NAI

Network Access Identifier

NAT

Network Address Translation

NCR

Network Controlled Repeater

NCR-MT

NCR Mobile Termination

NEF

Network Exposure Function

Network Function

NGAP

Next Generation Application Protocol

NID

Network identifier

NPN

Non-Public Network

New Radio

NRF

Network Repository Function

NS-AoS

Network Slice Area of Service

NSAC

Network Slice Admission Control

NSACF

Network Slice Admission Control Function

NSAG

Network Slice AS Group

NSI ID

Network Slice Instance Identifier

NSSAA

Network Slice-Specific Authentication and Authorization

NSSAAF

Network Slice-specific and SNPN Authentication and Authorization Function

NSSAI

Network Slice Selection Assistance Information

NSSF

Network Slice Selection Function

NSSP

Network Slice Selection Policy

NW-TT

Network-side TSN translator

NSSRG

Network Slice Simultaneous Registration Group

NSWO

Non-Seamless WLAN offload

NSWOF

Non-Seamless WLAN offload Function

NWDAF

Network Data Analytics Function

ONN

Onboarding Network

ON-SNPN

Onboarding Standalone Non-Public Network

PCF

Policy Control Function

PDB

Packet Delay Budget

PDR

Packet Detection Rule

PDU

Protocol Data Unit

PDV

Packet Delay Variation

PEGC

PIN Element with Gateway Capability

PEI

Permanent Equipment Identifier

PEMC

PIN Element with Management Capability

PER

Packet Error Rate

PFD

Packet Flow Description

Personal IoT Network

PINE

PIN Element

PLR

Packet Loss Rate

PNI-NPN

Public Network Integrated Non-Public Network

PPD

Paging Policy Differentiation

PPF

Paging Proceed Flag

PPI

Paging Policy Indicator

PSA

PDU Session Anchor

PSDB

PDU Set Delay Budget

PSER

PDU Set Error Rate

PSIHI

PDU Set Integrated Handling Information

PTP

Precision Time Protocol

PVS

Provisioning Server

QFI

QoS Flow Identifier

QMC

QoE Measurement Collection

QoE

Quality of Experience

RACS

Radio Capabilities Signalling optimisation

(R)AN

(Radio) Access Network

Residential Gateway

RIM

Remote Interference Management

RQA

Reflective QoS Attribute

RQI

Reflective QoS Indication

RSN

Redundancy Sequence Number

RTT

Round Trip Time

SA NR

Standalone New Radio

SBA

Service Based Architecture

SBI

Service Based Interface

SCP

Service Communication Proxy

Slice Differentiator

SEAF

Security Anchor Functionality

SEPP

Security Edge Protection Proxy

Service Function

SFC

Service Function Chain

SMF

Session Management Function

SMSF

Short Message Service Function

Sequence Number

SNPN

Stand-alone Non-Public Network

S-NSSAI

Single Network Slice Selection Assistance Information

SO-SNPN

Subscription Owner Standalone Non-Public Network

SSC

Session and Service Continuity

SSCMSP

Session and Service Continuity Mode Selection Policy

SST

Slice/Service Type

SUCI

Subscription Concealed Identifier

SUPI

Subscription Permanent Identifier

Software Version

Tracking Area

TAI

Tracking Area Identity

TNAN

Trusted Non-3GPP Access Network

TNAP

Trusted Non-3GPP Access Point

TNGF

Trusted Non-3GPP Gateway Function

TNL

Transport Network Layer

TNLA

Transport Network Layer Association

TSC

Time Sensitive Communication

TSCAC

TSC Assistance Container

TSCAI

Traffic Assistance Information

TSCTSF

Time Sensitive Communication and Time Synchronization Function

TSN

Time Sensitive Networking

TSN GM

TSN Grand Master

TSP

Traffic Steering Policy

TSS

Timing Synchronization Status

TSN Translator

TWIF

Trusted WLAN Interworking Function

UAS NF

Uncrewed Aerial System Network Function

UCMF

UE radio Capability Management Function

UDM

Unified Data Management

UDR

Unified Data Repository

UDSF

Unstructured Data Storage Function

Uplink

UL CL

Uplink Classifier

UPF

User Plane Function

URLLC

Ultra Reliable Low Latency Communication

URRP-AMF

UE Reachability Request Parameter for AMF

URSP

UE Route Selection Policy

VID

VLAN Identifier

VLAN

Virtual Local Area Network

W-5GAN

Wireline 5G Access Network

W-5GBAN

Wireline BBF Access Network

W-5GCAN

Wireline 5G Cable Access Network

W-AGF

Wireline Access Gateway Function

4 Architecture model and concepts p. 41

4.1 General concepts p. 41

The 5G System architecture is defined to support data connectivity and services enabling deployments to use techniques such as e.g. Network Function Virtualization and Software Defined Networking. The 5G System architecture shall leverage service-based interactions between Control Plane (CP) Network Functions where identified. Some key principles and concept are to:

Separate the User Plane (UP) functions from the Control Plane (CP) functions, allowing independent scalability, evolution and flexible deployments e.g. centralized location or distributed (remote) location.
Modularize the function design, e.g. to enable flexible and efficient network slicing.
Wherever applicable, define procedures (i.e. the set of interactions between network functions) as services, so that their re-use is possible.
Enable each Network Function and its Network Function Services to interact with other NF and its Network Function Services directly or indirectly via a Service Communication Proxy if required. The architecture does not preclude the use of another intermediate function to help route Control Plane messages (e.g. like a DRA).
Minimize dependencies between the Access Network (AN) and the Core Network (CN). The architecture is defined with a converged core network with a common AN - CN interface which integrates different Access Types e.g. 3GPP access and non-3GPP access.
Support a unified authentication framework.
Support "stateless" NFs, where the "compute" resource is decoupled from the "storage" resource.
Support capability exposure.
Support concurrent access to local and centralized services. To support low latency services and local access to data networks, UP functions can be deployed close to the Access Network.
Support roaming with both Home routed traffic as well as Local breakout traffic in the visited PLMN.

4.2 Architecture reference model p. 42

4.2.1 General p. 42

This specification describes the architecture for the 5G System. The 5G architecture is defined as service-based and the interaction between network functions is represented in two ways.

A service-based representation, where network functions (e.g. AMF) within the Control Plane enables other authorized network functions to access their services. This representation also includes point-to-point reference points where necessary.
A reference point representation, shows the interaction exist between the NF services in the network functions described by point-to-point reference point (e.g. N11) between any two network functions (e.g. AMF and SMF).

Service-based interfaces are listed in clause 4.2.6. Reference points are listed in clause 4.2.7.

Network functions within the 5GC Control Plane shall only use service-based interfaces for their interactions.

NFs and NF services can communicate directly, referred to as Direct Communication, or indirectly via the SCP, referred to as Indirect Communication. For more information on communication options, see Annex E and clauses under clause 6.3.1 and clause 7.1.2.

In addition to the architecture descriptions in clause 4, the following areas are further described in other specifications:

NG-RAN architecture is described in TS 38.300 and TS 38.401.
Security architecture is described in TS 33.501 and TS 33.535.
Charging architecture is described in TS 32.240.
5G Media streaming architecture is described in TS 26.501.

4.2.2 Network Functions and entities p. 42

The 5G System architecture consists of the following network functions (NF):

Authentication Server Function (AUSF).
Access and Mobility Management Function (AMF).
Data Network (DN), e.g. operator services, Internet access or 3rd party services.
Unstructured Data Storage Function (UDSF).
Network Exposure Function (NEF).
Network Repository Function (NRF).
Network Slice Admission Control Function (NSACF).
Network Slice-specific and SNPN Authentication and Authorization Function (NSSAAF).
Network Slice Selection Function (NSSF).
Policy Control Function (PCF).
Session Management Function (SMF).
Unified Data Management (UDM).
Unified Data Repository (UDR).
User Plane Function (UPF).
UE radio Capability Management Function (UCMF).
Application Function (AF).
User Equipment (UE).
(Radio) Access Network ((R)AN).
5G-Equipment Identity Register (5G-EIR).
Network Data Analytics Function (NWDAF).
CHarging Function (CHF).
Time Sensitive Networking AF (TSN AF).
Time Sensitive Communication and Time Synchronization Function (TSCTSF).
Data Collection Coordination Function (DCCF).
Analytics Data Repository Function (ADRF).
Messaging Framework Adaptor Function (MFAF).
Non-Seamless WLAN Offload Function (NSWOF).

NOTE:
The functionalities provided by DCCF and/or ADRF can also be hosted by an NWDAF.
Edge Application Server Discovery Function (EASDF).

The 5G System architecture also comprises the following network entities:

Service Communication Proxy (SCP).
Security Edge Protection Proxy (SEPP).

The functional descriptions of these Network Functions and entities are specified in clause 6.

Non-3GPP InterWorking Function (N3IWF).
Trusted Non-3GPP Gateway Function (TNGF).
Wireline Access Gateway Function (W-AGF).
Trusted WLAN Interworking Function (TWIF).