5G核心网关键技术和功能介绍
目录
1.5G核心网架构和各主要NF功能描述
2.5G核心网关键技术介绍
-基于服务的构架SBA
-控制面和用户面分离CUPS
-计算与存储分离
-网络切片构架和选择NSSF
3.注册管理和连接管理RM/C M
-用户标识
-不同的注册管理流程和功能
-几种不同的连接管理状态分析
4.会话管理SM
-PDU会话的一些特性介绍
-会话和业务连续性模式介绍
-基于流的QoS模型介绍
-边缘计算和本地路由功能
5.5G的关键呼叫流程
-注册流程
-PDU会话建立流程
-切换流程
1.5G核心网架构和各主要NF功能描述
5G Service Based Architecture (SBA)
AUSF UE
(R)AN UPF N2N3N1
N9AMF N4AF PDN
N6
N4PCF SMF UDM USER PLANE CONTROL PLANE Local PDN UPF N1N2UE AP N3IWF N3NEF 3rd party appl.DSF NRF Service based interfaces (APIs) “on demand”Authenti-fication
Access &Mobility Mgmt
Unified data mgmt 5G Core (SBA)
Service Based Architecture
Application Function Session Mgmt Data Storage Function User Plane Function
Policy Ctrl Function Network repository Function Network Exposure function AMF: Access and Mobility management Function
SMF: Session Management Function
UPF: User Plane Function
UDSF: Unstructured Data Storage Function AUSF: Authentication Server Function UDM: Unified Data Management UDR: Unified Data Repository N3IWF: Non-3GPP Interworking Function NRF: Network Repository Function NEF: Network Exposure Function NSSF: Network Slice Selection Function PCF: Policy Control Function
Access and Mobility Management function (AMF)
?Mandatory functionality
?Termination of RAN control interface (N2)
?Termination of NAS (N1), NAS ciphering and integrity protection
?Access authentication and authorization
?Security anchor function and security context mgmt for access security key handling
?Registration, connection, reachability, and mobility management
?Session mgmt message transport and proxy between UE and Session Management Function (SMF)
?SMS transport between UE and SMSF
?Lawful interception
?Optional functionality
?Support of mandatory functionality for non-3GPP access
?N3IWF N2 interface termination and NAS signaling
5G System Architecture
AMF SMF PCF
EIR
AUSF
UE
N1
N2
N3
Internet
UPF
4G/5G
N4
IMS
N3IWF
NSSF
N5
SMSF
NRF UDSF UDR NEF AF
UDM
n3GPP
All network functions can interact with NRF,
UDSF, UDM, UDR, and NEF as necessary
BGW
HSS
TAS
IMS
N6
MRF
LMF
Session Management function (SMF)
?Session establishment, modify and release inc N3 tunnel ?UE IP address allocation & management
?Selection and control of UP function (UPF)
?UPF traffic steering configuration to proper destination ?Termination of interfaces towards Policy control functions ?Control part of policy enforcement and QoS
?Charging data collection and support of charging interfaces ?Control and coordination of charging data collection at UPF ?Termination of SM parts of NAS messages
?Downlink Data Notification
?Initiator of AN specific SM information via AMF over N2?Determine SSC mode of a session
?Lawful intercept
?Roaming functionality (local QoS, charging, LI)
5G System Architecture
AMF SMF PCF
EIR
AUSF
UE
N1
N2
N3
Internet
UPF
4G/5G
N4
IMS
N3IWF
NSSF
N5
SMSF
NRF UDSF UDR NEF AF
UDM
n3GPP
All network functions can interact with NRF,
UDSF, UDM, UDR, and NEF as necessary
BGW
HSS
TAS
IMS
N6
MRF
LMF
User plane function (UPF)
?Anchor point for Intra-/Inter-RAT mobility (when applicable)?External PDU session point of interconnect to Data Network ?Packet routing & forwarding
?Packet inspection and User plane part of Policy rule enforcement
?Lawful intercept (UP collection)
?Traffic usage reporting.
?Uplink classifier to support routing traffic flows to a data network.
?Branching point to support multi-homed PDU session.?QoS handling for user plane, e.g. packet filtering, gating, UL/DL rate enforcement
?Uplink Traffic verification (SDF to QoS flow mapping).?Transport level packet marking in the uplink and downlink.?Downlink packet buffering and downlink data notification triggering.
5G System Architecture
AMF SMF PCF
EIR
AUSF
UE
N1
N2
N3
Internet
UPF
4G/5G
N4
IMS
N3IWF
NSSF
N5
SMSF
NRF UDSF UDR NEF AF
UDM
n3GPP
All network functions can interact with NRF,
UDSF, UDM, UDR, and NEF as necessary
BGW
HSS
TAS
IMS
N6
MRF
LMF
Network Repository Function (NRF)
?Supports service discovery function
?Receive NF Discovery Request from NF instance, and provides the information of the discovered NF instances (be discovered) to the NF instance
?Maintains the NF profile of available NF instances and their supported services (e.g. ID, Type, PLMN, Slice, FQDN,
capabilities, authorization information, service names)
?All network functions interact with NRF
?Multiple NRFs can be deployed in network slicing per PLMN, per group of slices, or slice specific
?In roaming cases VPLMN and HPLMN may be used
5G System Architecture
AMF SMF PCF
EIR
AUSF
UE
N1
N2
N3
Internet
UPF
4G/5G
N4
IMS
N3IWF
NSSF
N5
SMSF
NRF UDSF UDR NEF AF
UDM
n3GPP
All network functions can interact with NRF,
UDSF, UDM, UDR, and NEF as necessary
BGW
HSS
TAS
IMS
N6
MRF
LMF
Unstructured Data Storage Function (UDSF)
?Storage and retrieval of information as unstructured data by any NF (e.g. context, state, session)
?All network functions can interact with UDSF (via N18/Nudsf interface)
?NFs may share a UDSF for storing their respective unstructured data or may each have their own UDSF ?Deployments can choose to collocate UDSF with UDR
Unstructured Data Storage Function (UDSF)
Context State Session
Any NF
N18/Nudsf
5G System Architecture
AMF SMF PCF
EIR
AUSF
UE
N1
N2
N3
Internet
UPF
4G/5G
N4
IMS
N3IWF
NSSF
N5
SMSF
NRF UDSF UDR NEF AF
UDM
n3GPP
All network functions can interact with NRF,
UDSF, UDM, UDR, and NEF as necessary
BGW
HSS
TAS
IMS
N6
MRF
LMF
Unified Data Repository (UDR)
?Storage and retrieval of subscription data by the UDM FE ?Storage and retrieval of policy data by the PCF.
?Storage and retrieval of structured data for exposure, and application data (including Packet Flow Descriptions (PFDs) for application detection, application request information for multiple UEs), by the NEF
?Deployments can choose to collocate UDSF with UDR
Unified Data Repository (UDR)
Subscription Policy Exposure Application
UDM FE PCF FE NEF FE
Nudr
5G System Architecture
AMF SMF PCF
EIR
AUSF
UE
N1
N2
N3
Internet
UPF
4G/5G
N4
IMS
N3IWF
NSSF
N5
SMSF
NRF UDSF UDR NEF AF
UDM
n3GPP
All network functions can interact with NRF,
UDSF, UDM, UDR, and NEF as necessary
BGW
HSS
TAS
IMS
N6
MRF
LMF
Unified Data Management (UDM)
?3GPP AKA Authentication Credential Processing
?User Identification Handling
?Access Authorization
?Registration/Mobility management
?Subscription management
?SMS management
?UDM uses subscription data and authentication data that may be stored in UDR
5G System Architecture
AMF
UPF
SMF
PCF
EIR
AUSF
UE
N1
N2
N3
Internet
UPF
4G/5G
N4
N9
IMS
N4
N3IWF
NSSF
N5
N7
N11
N22N12
SMSF
N20
NRF UDSF UDR NEF AF
N17
N15
UDM
N8
n3GPP
All network functions can interact with NRF,
UDSF, UDM, UDR, and NEF as necessary
BGW
HSS
TAS
IMS
N6
MRF
Network Exposure Function (NEF)?Securely expose the services and capabilities provided by
3GPP network functions for e.g 3rd party, internal
exposure/re-exposure, Application Functions, Edge
Computing
?Provides a means for the Application Functions to securely provide information to 3GPP network, e.g. Mobility Pattern, communication pattern
?Authenticate, authorize and throttle the Application Functions
?Translation information between AF and internal network function
?Receives information from other network functions (based on exposed capabilities of other network functions)
?May implement a Front End (NEF FE) to store the received information as structured data using a standardized
interface to a Unified Data Repository (UDR). The stored
information can be accessed and "re-exposed" by the NEF to other network functions and Application Functions, and used for other purposes such as analytics.
5G System Architecture
AMF SMF PCF
EIR
AUSF
UE
N1
N2
N3
Internet
UPF
4G/5G
N4
IMS
N3IWF
NSSF
N5
SMSF
NRF UDSF UDR NEF AF
UDM
n3GPP
All network functions can interact with NRF,
UDSF, UDM, UDR, and NEF as necessary
BGW
HSS
TAS
IMS
N6
MRF
LMF
Network Slice Selection Function (NSSF)
?Selecting the set of network slice instances serving the UE ?Determining the Allowed NSSAI
?Determining the AMF Set to be used to serve the UE, or, based on configuration, a list of candidate AMF(s), possibly by querying the NRF.
5G System Architecture
AMF SMF PCF
EIR
AUSF
UE
N1
N2
N3
Internet
UPF
4G/5G
N4
IMS
N3IWF
NSSF
N5
SMSF
NRF UDSF UDR NEF AF
UDM
n3GPP
All network functions can interact with NRF,
UDSF, UDM, UDR, and NEF as necessary
BGW
HSS
TAS
IMS
N6
MRF
LMF
Authentication Server Function (AUSF)
?Supports Authentication Server Function (AUSF) as specified by SA WG3
5G System Architecture
AMF SMF PCF
EIR
AUSF
UE
N1
N2
N3
Internet
UPF
4G/5G
N4
IMS
N3IWF
NSSF
N5
SMSF
NRF UDSF UDR NEF AF
UDM
n3GPP
All network functions can interact with NRF,
UDSF, UDM, UDR, and NEF as necessary
BGW
HSS
TAS
IMS
N6
MRF
LMF
Policy Control Function (PCF)
?Supports unified policy framework to govern network behavior
?Provides policy rules to Control Plane function(s) to enforce them
?Implements a Front End (PCF FE) to access subscription information relevant for policy decisions in a Unified Data Repository (UDR)
5G System Architecture
AMF SMF PCF
EIR
AUSF
UE
N1
N2
N3
Internet
UPF
4G/5G
N4
IMS
N3IWF
NSSF
N5
SMSF
NRF UDSF UDR NEF AF
UDM
n3GPP
All network functions can interact with NRF,
UDSF, UDM, UDR, and NEF as necessary
BGW
HSS
TAS
IMS
N6
MRF
LMF
Non-3GPP InterWorking Function (N3IWF)?UE IPSEC/IKE tunnel termination
?Termination of N2 and N3 interfaces to 5G Core Network for Control-Plane and user-plane respectively
?Relaying uplink and downlink control-plane NAS (N1) signaling between the UE and AMF
?Handling of N2 signaling from SMF (relayed by AMF) related to PDU sessions and QoS
?Establishment of IPsec Security Association (IPsec SA) to support PDU Session traffic
?Relaying uplink and downlink user-plane packets between the UE and UPF. (De-capsulation/Encapsulation of packets for IPSec and N3 tunneling)
?Enforcing QoS corresponding to N3 packet marking, taking into account QoS requirements associated to such marking received over N2
?N3 user-plane packet marking in the uplink.
?Local mobility anchor within untrusted non-3GPP access networks using MOBIKE
?Supporting AMF selection
5G System Architecture
AMF SMF PCF
EIR
AUSF
UE
N1
N2
N3
Internet
UPF
4G/5G
N4
IMS
N3IWF
NSSF
N5
SMSF
NRF UDSF UDR NEF AF
UDM
n3GPP
All network functions can interact with NRF,
UDSF, UDM, UDR, and NEF as necessary
BGW
HSS
TAS
IMS
N6
MRF
LMF
2.5G核心网关键技术介绍
基于服务的构架SBA
Technology behind: Modularity and SBA