1、5G核心网关键技核心网关键技术术和和功能功能介绍介绍2目录目录1.5G核心网架构和各主核心网架构和各主要要NF功能功能描描述述2.5G核心网关键技术介绍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NSSF3.注册管理和连接管理注册管理和连接管理RM/CM-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
2、核心网架构和各各主主要要NF功功能能描描述述5G Service Based Architecture (SBA)AUSFUE(R)ANUPFN2N3N1N9AMFN4AFPDNN6N4SMFUDMUSER PLANELocal PDNUPFN1N2UEAPN3IWFN3NEF3rd partyappl.DSFPCFNRFCONTROL PLANEAuthenti-ficationAccess & Mobility MgmtUnified data mgmt5G Core (SBA)Service Based ArchitectureApplicationSession FunctionMgm
3、tData Storage FunctionUser Plane FunctionPolicy Ctrl FunctionNetwork repository FunctionService based interfaces (APIs) “on demand”Network Exposure functionAMF: Access and Mobility management FunctionSMF: Session Management Function UPF: User Plane FunctionUDSF: Unstructured Data Storage FunctionAUS
4、F: Authentication Server Function UDM: Unified Data Management UDR: Unified Data RepositoryN3IWF: Non-3GPP Interworking FunctionNRF: Network Repository Function NEF: Network Exposure Function NSSF: Network Slice Selection Function PCF: Policy Control Function4Access and Mobility Management function
5、(AMF)Mandatory functionalityTermination of RAN control interface (N2)Termination of NAS (N1), NAS ciphering and integrity protectionAccess authentication and authorizationSecurity anchor function and security context mgmt for access security key handlingRegistration, connection, reachability, and mo
6、bility managementSession mgmt message transport and proxy between UE and Session Management Function (SMF)SMS transport between UE and SMSFLawful interceptionOptional functionalitySupport of mandatory functionality for non-3GPP accessN3IWF N2 interface termination and NAS signaling5G System Architec
7、tureAMFSMFPCFAUSFUEN1N2N3UPF4G/5GN4IMSN3IWFNSSFN5SMSFEIRNRFUDSFUDMUDRNEFn3GPPAll network functions can interact with NRF, UDSF, UDM, UDR, and NEF as necessaryBGWHSSTASN6MRFLMF5 Nokia 2018Session Management function (SMF)Session establishment, modify and release inc N3 tunnelUE IP address allocation
8、& managementSelection and control of UP function (UPF)UPF traffic steering configuration to proper destinationTermination of interfaces towards Policy control functionsControl part of policy enforcement and QoSCharging data collection and support of charging interfacesControl and coordination of cha
9、rging data collection at UPFTermination of SM parts of NAS messagesDownlink Data NotificationInitiator of AN specific SM information via AMF over N2Determine SSC mode of a sessionLawful interceptRoaming functionality (local QoS, charging, LI)5G System ArchitectureAMFSMFPCFAUSFUEN1N2N3UPF4G/5GN4IMSN3
10、IWFNSSFN5SMSFEIRNRFUDSFUDMUDRNEFn3GPPAll network functions can interact with NRF, UDSF, UDM, UDR, and NEF as necessaryBGWHSSTASN6MRFLMF6 Nokia 2018User plane function (UPF)Anchor point for Intra-/Inter-RAT mobility (when applicable)External PDU session point of interconnect to Data NetworkPacket rou
11、ting & forwardingPacket inspection and User plane part of Policy rule enforcementLawful 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 fi
12、ltering, gating, UL/DL rate enforcementUplink 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 ArchitectureAMFSMFPCFAUSFUEN1N2N3UPF4G/5GN4IMSN3IWFNSSFN5SMSFEIRNRFUDSF
13、UDMUDRNEFn3GPPAll network functions can interact with NRF, UDSF, UDM, UDR, and NEF as necessaryBGWHSSTASN6MRFLMF7 Nokia 2018Network Repository Function (NRF)Supports service discovery functionReceive NF Discovery Request from NF instance, and provides the information of the discovered NF instances (
14、be discovered) to the NF instanceMaintains 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 NRFMultiple NRFs can be deployed in network slicing per PLMN,
15、 per group of slices, or slice specificIn roaming cases VPLMN and HPLMN may be used5G System ArchitectureAMFSMFPCFEIRAUSFUEN1N2N3UPF4G/5GN4IMSN3IWFNSSFN5SMSFNRFUDSFUDRNEFUDMn3GPPAll network functions can interact with NRF, UDSF, UDM, UDR, and NEF as necessaryBGWHSSTASN6MRFLMF8 Nokia 2018Unstructured
16、 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 UDSFDepl
17、oyments can choose to collocate UDSF with UDRUnstructured Data Storage Function (UDSF)ContextStateSessionAny NFN18/Nudsf5G System ArchitectureAMFSMFPCFAUSFUEN1N2N3UPF4G/5GN4IMSN3IWFNSSFN5SMSFNRFUDSFUDMUDRNEFn3GPPAll network functions can interact with NRF, UDSF, UDM, UDR, and NEF as necessaryBGWHSST
18、ASN6MRFEIRLMF9 Nokia 2018Unified Data Repository (UDR)Storage and retrieval of subscription data by the UDM FEStorage 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 detecti
19、on, application request information for multiple UEs), by the NEFDeployments can choose to collocate UDSF with UDRUnified Data Repository (UDR)SubscriptionPolicyExposureApplicationNEF FENudrUDM FEPCF FE5G System ArchitectureAMFSMFPCFEIRAUSFUEN1N2N3UPF4G/5GN4IMSN3IWFNSSFN5SMSFUDRNEFNRFUDSFUDMn3GPPAll
20、 network functions can interact with NRF, UDSF, UDM, UDR, and NEF as necessaryBGWHSSTASN6MRFLMF10 Nokia 2018Unified Data Management (UDM)3GPP AKA Authentication Credential ProcessingUser Identification HandlingAccess AuthorizationRegistration/Mobility managementSubscription managementSMS managementU
21、DM uses subscription data and authentication data that may be stored in UDR5G System ArchitectureAMFUPFSMFPCFEIRAUSFUEN1N2N3UPF4G/5GN4N9N4N3IWFNSSFN5N7N11N22SMSFN20NRFUDSFUDRNEFAFN15UDMN12N8N17n3GPPAll network functions can interact with NRF, UDSF, UDM, UDR, and NEF as necessaryIMSInternetN611 Nokia
22、 2018Network 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 ComputingProvides a means for the Application Functions to securely provide information to 3GPP network,
23、e.g. Mobility Pattern, communication patternAuthenticate, authorize and throttle the Application FunctionsTranslation information between AF and internal network functionReceives information from other network functions (based on exposed capabilities of other network functions)May implement a Front
24、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
25、 System ArchitectureAMFSMFPCFEIRAUSFUEN1N2N3UPF4G/5GN4IMSN3IWFNSSFN5SMSFNRFUDSFUDRNEFUDMn3GPPAll network functions can interact with NRF, UDSF, UDM, UDR, and NEF as necessaryBGWHSSTASN6MRFLMF12 Nokia 2018Network Slice Selection Function (NSSF)Selecting the set of network slice instances serving the
26、UEDetermining the Allowed NSSAIDetermining 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 ArchitectureAMFSMFPCFEIRAUSFUEN1N2N3UPF4G/5GN4IMSN3IWFNSSFN5SMSFNRFUDSFUDRNEFUDMn3GPPAll network functions can interact wi
27、th NRF, UDSF, UDM, UDR, and NEF as necessaryBGWHSSTASN6MRFLMF13 Nokia 2018Authentication Server Function (AUSF)Supports Authentication Server Function (AUSF) as specified by SA WG35G System ArchitectureAMFSMFPCFEIRAUSFUEN1N2N3UPF4G/5GN4IMSN3IWFNSSFN5SMSFNRFUDSFUDRNEFUDMn3GPPAll network functions can
28、 interact with NRF, UDSF, UDM, UDR, and NEF as necessaryBGWHSSTASN6MRFLMF14 Nokia 2018Policy Control Function (PCF)Supports unified policy framework to govern network behaviorProvides policy rules to Control Plane function(s) to enforce themImplements a Front End (PCF FE) to access subscription info
29、rmation relevant for policy decisions in a Unified Data Repository (UDR)5G System ArchitectureAMFSMFPCFEIRAUSFUEN1N2N3UPF4G/5GN4IMSN3IWFNSSFN5SMSFNRFUDSFUDRNEFUDMn3GPPAll network functions can interact with NRF, UDSF, UDM, UDR, and NEF as necessaryBGWHSSTASN6MRFLMF15 Nokia 2018Non-3GPP InterWorking
30、Function (N3IWF)UE IPSEC/IKE tunnel terminationTermination of N2 and N3 interfaces to 5G Core Network for Control-Plane and user-plane respectivelyRelaying uplink and downlink control-plane NAS (N1) signaling between the UE and AMFHandling of N2 signaling from SMF (relayed by AMF) related to PDU ses
31、sions and QoSEstablishment of IPsec Security Association (IPsec SA) to support PDU Session trafficRelaying 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
32、account QoS requirements associated to such marking received over N2N3 user-plane packet marking in the uplink.Local mobility anchor within untrusted non-3GPP accessnetworks using MOBIKESupporting AMF selection5G System ArchitectureAMFSMFPCFEIRAUSFUEN1N2N3UPF4G/5GN4IMSN3IWFNSSFN5SMSFNRFUDSFUDRNEFUDM
33、n3GPPAll network functions can interact with NRF, UDSF, UDM, UDR, and NEF as necessaryBGWHSSTASN6MRFLMF16 Nokia 20182. 5G核心网关键技核心网关键技术术介绍介绍 Nokia 2018基于服务的构架SBA Nokia 2018Technology behind: Modularity and SBA19 Nokia 2018 Control Plane An NF service is one type of capability NF Service Producer Auth
34、orized NF Service Consumer Network Function may expose one or more NF services through a service-based interface, two mechanisms- Request-response“- Subscribe-NotifyNetwork Function Service Framework20 Nokia 2018SBA requires service framework and identification of services21 Nokia 2018FrameworkConce
35、ptDiscoveryNF discovery, NF service discovery enables a CP NF to discover a NF instance(s) that provides theexpected NF service(s). It is implemented either via configuration or optionally by using the NRFThe requester NF performs the selection if the NRF returns more than one optionsThe requester N
36、F might cache the results of the discovery request for subsequent use Multiple NRFs can be deployed at different levels:PLMN level (the NRF is configured with information for the whole PLMN)shared-slice level (the NRF is configured with information relevant for the common NFs of a setof Network Slic
37、es)slice-specific level (the NRF is configured with information belonging to an S-NSSAI)AuthorizationEntails Two steps:Check whether the requester NF is permitted to discover the requested NF instance during the NF service discovery procedure NF level granularityCheck whether the requester NF is per
38、mitted to access the requested NF for consuming the NF service. This is either per NF or per UE/roaming agreement granularity. NF Service authorization per UE granularity is embedded in the related NF service logicRegistration and De-registrationRegistration / De-registration of NF profile and NF se
39、rvices with Network repository function viadirect interaction between NF NRF or OAM Uniform solution for all 5G Service-Based Interfaces SBA protocol: HTTP/2 Transport: TCP Serialization protocol: JSON The OpenAPI 3.0.0 is adopted as the Interface Definition Language API design style: RESTful APIs w
40、henever possible, complemented by custom methods for service operations that cannot be designed as CRUD operations22 Nokia 2018SBA protocol solution Nokia 2018控制面和用户面分离CUPSTechnology behind: CP UP SeparationCentralized CP and BUSstructureDistributed UPUPF selection and re-selectionClose to UE (Edge)
41、ULCLBranching-point24 Nokia 2018selective traffic routing25 Nokia 2018 IPv4, IPv6 & Ethernet PDUs Transparent to UE- exist more than one UPF- but one UL CL is connected to RAN Classification rules provided in run time by SMF Classifies based on target characteristics of the flowsUplink Classifier(UL
42、-CL)26 Nokia 2018 multi PDU Session Anchorwith multiple IPv6 prefixes. branch out at a Branching Point UPF- forwarding UL traffic towards different PDU Session Anchors and merge DL traffic to UE The use of multiple IPv6 prefixes :- a Branching Point spread UL traffic based on Source Prefix- to suppo
43、rt make-before-break servicecontinuity SSC mode 3- to support UE access both local service and central serviceUsage of IPv6 multi-homing PDU Session27 Nokia 2018 Nokia 2018计算与存储分离5G Data Storage architecturesAllows any control plane NF to store and retrieve its unstructured data (session state) into
44、/from a UDSF (Unstructured Data Storage Network Function)UDSF belongs to the same PLMN where theNF is locatedCP NFs may share a UDSF or may each have its own UDSF5G phase 1 specifies AMF procedures if UE context is stored in UDSFN18/Nudsf: Protocol will not be specified in Rel. 15Unstructured Data S
45、torage Function (UDSF)Unified Data Repository (UDR)Allows the UDM, PCF, NEF to store data in the UDR (Unified Data Repository)UDR can be deployed in each PLMN. There can be multiple UDRs deployed in a network each accommodating different data sets/subsets. Deployments where a UDR serves a single NF
46、and stores its data and thus can be integrated with this NF, can be possible, e.g. a UDM with build-in UDRData exposed via Nudr (subscription, policy, structured data for exposure, application request information for multiple UEs) shall be standardized. In addition it shall be possible to access ope
47、rator specific data sets/data not standardized. The organization of the data stored in UDR shall not be standardizedNudr: service based interface http2 based. Nudr is always intra-PLMN, Nudm is inter- PLMN in roamingN18/NudsfAny NFUDSFSubscription DataPolicy DataStructured Data for exposureApplicati
48、on DataUDRUDM FEPCF FENEF FENudr29 Nokia 2018Technology behind: Compute Storage Separationstateless NFV30 Nokia 2018 Nokia 2018网络切片构架和选择NSSFNetwork Slice IdentificationN. SSAI identifies a Network Slice,comprised of:A Slice/Service type (SST), refers to the expected Network Slice behaviour in terms
49、of features and services;A Slice Differentiator (SD), optional to differentiate multiple Network Slices of the same Slice/Service type.can have standard values or non-standard valuesThe NSSAI is a collection of S-NSSAIs.a Network Slice instance can be associated with one or more S-NSSAIs, and an S-N
50、SSAI can be associated with one or more Network Slice instances.32 Nokia 2018Slice Examples in 5GC & 5G RANeMBBUPFSMFUPFSMFeMBB CONTROL PLANE USER PLANEAMFUPFSMFeMTCSHAREDDEDICATEDSLICE #1SLICE #2SLICE #3AMFRRC/PDCPN2MACPHYSDAPPDCPSDAPPDCPRRC/PDCPN2SDAPUE 1UE 25G (R)ANN1 ( SST#1, SD#A)N1 ( SST#1, SD
