Outline Objective 5 G System Architecture Network Slicing

Outline • • • Objective 5 G System Architecture Network Slicing Registration Network Slicing PDU session Network Slicing Handover Network Slicing Qo. S

3 Objective • The objective of this course is to learn the definition, registration, PDU session, handover, security, and enhancement of network slicing in 5 G 3 GGP specification.

教育部補助 5 G行動寬頻跨校教學聯盟 5 G Network Slicing 5 G System Architecture

5 Non-Roaming 5 G System Architecture Reference Point Representation NSSF N 13 AUSF N 22 UDM N 8 N 12 N 10 N 11 AMF N 1 N 2 UE (R)AN SMF N 15 N 14 N 7 PCF N 5 N 4 UPF N 3 N 6 DN N 9 • • • Authentication Server Function (AUSF) Access and Mobility Management Function (AMF) Data Network (DN) 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) Application Function (AF) User Equipment (UE) (Radio) Access Network ((R)AN) AF

6 5 G System Architecture - Non-Roaming Service-Based Interface Representation Network Function (NF) Service Based Interface (SBI) NSSF Nnssf NEF Nnef NRF Npcf Nnrf Namf Nausf Service Based AUSF Architecture (SBA) UE • Authentication Server Function (AUSF) Access and Mobility Management Function (AMF) • • Network Exposure Function (NEF) • Network Repository Function (NRF) • Network Slice Selection Function (NSSF) • • Policy Control Function (PCF) UDM AF Nudm Naf Nsmf AMF N 1 • • • PCF SMF N 2 (R)AN N 4 N 3 UPF Session Management Function (SMF) Unified Data Management (UDM) Unified Data Repository (UDR) User Plane Function (UPF) Application Function (AF) User Equipment (UE) (Radio) Access Network ((R)AN) N 6 DN Data Network

7 PLMN Introduction IMSI stored in UE SIM card MCC : Mobile Country Code • Include MCC and MNC : Mobile Network Code PLMN : Public Land Mobile Network • MCC + MNC HPLMN : Home PLMN HPLMN VPLMN : Visited PLMN • PLMN same as UE MCC and MNC VPLME • UE visited PLMN with difference MCC and MNC from UE UE IMSI • MCC = 466 • MNC = 11 VPLMN = 46000 HPLMN = 46611

8 5 G System Architecture - Local Breakout Scenario Service-Based Interface Representation SEcurity Protection Proxy (SEPP) NSSF Nnssf NEF NRF Npcf Nnrf Nnef PCF AF Naf v. SEPP Namf Nsmf AMF N 1 UE (R)AN N 32 Nudm Nausf h. SEPP Nnrf Nnef SMF N 2 AUSF UDM NEF NRF N 4 N 3 UPF N 6 DN N 9 VPLMN HPLMN Npcf PCF

9 5 G System Architecture - Home Routed scenario Service-Based Interface Representation NSSF Nnssf NEF NRF v. SEPP Namf N 1 UE N 32 Nsmf AMF (R)AN UPF N 9 VPLMN AF Naf Nnssf Nnef Nnrf Npcf NEF NRF N 4 N 9 NSSF h. SEPP SMF N 4 N 3 Nausf Nudm Nsmf SMF N 2 AUSF UDM Npcf Nnrf Nnef PCF UPF N 6 N 9 HPLMN DN PCF

10 5 G Service Based Architecture Control plane function group NSSF Nnssf NRF NEF Nnef Npcf Nnrf Namf Nausf N 1 UDM Nudm AF Naf Nsmf AMF AUSF UE PCF SMF N 4 N 2 (R)AN N 3 UPF N 9 User plane function N 6 DN

11 5 G Service Based Architecture User Plane Function (UPF) Control plane function group N 3 UE NG Radio Access Network Non-3 GPP Access Network (N 3 IWF functions ) g. Node. B UPF N 9 User plane function DN N 6

12 User Plane Function (UPF) Functionalities • Anchor point for Intra-/Inter-RAT mobility • External PDU Session point of interconnect to Data Network Packet routing & forwarding • – When applicable • • – support of Uplink classifier to route traffic flows to an instance of a data network, support of Branching point to support multi-homed PDU Session • Packet inspection – Application detection based on service data flow template and the optional PFDs received from the SMF in addition • User Plane part of policy rule enforcement – Gating, Redirection, Traffic steering • Lawful intercept – UP collection • Traffic usage reporting Qo. S handling for user plane – UL/DL rate enforcement, Reflective Qo. S marking in DL Uplink Traffic verification – SDF to Qo. S Flow mapping • • Transport level packet marking in the uplink and downlink Downlink packet buffering and downlink data notification triggering Sending and forwarding of one or more "end marker" to the source NG-RAN node ARP proxying and / or IPv 6 Neighbour Solicitation Proxying functionality for the Ethernet PDUs – The UPF responds to the ARP and / or the IPv 6 Neighbour Solicitation Request by providing the MAC address corresponding to the IP address sent in the request

13 User Plane Function (UPF) Endpoints Access Network N 3 Edge Network I-UPF N 9 I-UPF : Intermediate PDU Core Network UPF (PSA) N 6 DN PSA : PDU session anchor

14 5 G Service Based Architecture Session Management Function (SMF) Control plane function group Nsmf SMF N 4 N 3 UE NG Radio Access Network Non-3 GPP Access Network (N 3 IWF functions ) g. Node. B UPF N 9 User plane function DN N 6

15 Session Management Function (SMF) Functionalities • Session Management – Session Establishment, modify and release, including tunnel maintain between UPF and AN node • DHCPv 4 and DHCPv 6 functions • ARP proxying and / or IPv 6 Neighbour Solicitation Proxying functionality for the Ethernet PDUs – The SMF responds to the ARP and / or the IPv 6 Neighbour Solicitation Request by providing the MAC address corresponding to the IP address sent in the request • Selection and control of UP function, – Including controlling the UPF to proxy ARP or IPv 6 Neighbour Discovery, or to forward all ARP/IPv 6 Neighbour Solicitation traffic to the SMF, for Ethernet PDU Sessions • Configures traffic steering at UPF to route traffic to proper destination Termination of interfaces towards Policy control functions Lawful intercept – • – Server and client • • UE IP address allocation & management – Including optional Authorization • • For SM events and interface to LI System 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, sent via AMF over N 2 to AN Determine SSC mode of a session. Roaming functionality: – – Handle local enforcement to apply Qo. S SLAs (VPLMN). Charging data collection and charging interface (VPLMN). Lawful intercept (in VPLMN for SM events and interface to LI System). Support for interaction with external DN for transport of signalling for PDU Session authorization/authentication by external DN.

16 Session Management Function (SMF) PCF The foundation of a policy framework • Typical Qo. S and charging rules • Network Slice selection Namf AMF UDM Npcf N 7 N 10 Nsmf Add, modify or delete a PDU session N 11 The subscriber profile information Nudm SMF sends messages to the UPF using the N 4 Packet Forwarding Control Protocol UPF • Role of DHCP server • IP Address Management • Maintains a record of PDU session state together with the UPF

17 5 G Service Based Architecture Access and Mobility Management Function (AMF) Control plane function group Namf Nsmf AMF N 1 SMF N 4 N 2 N 3 UE NG Radio Access Network Non-3 GPP Access Network (N 3 IWF functions ) g. Node. B UPF N 9 User plane function DN N 6

Access and Mobility Management Function (AMF) Functionalities • Termination of RAN CP interface (N 2) • Termination of NAS (N 1) , NAS ciphering and integrity protection • Registration management • Connection management • Reachability management • Mobility Management • Lawful intercept – For AMF events and interface to LI System • Provide transport for SM messages between UE and SMF • Transparent proxy for routing SM messages 18 • Access Authentication • Access Authorization • Provide transport for SMS messages between UE and SMSF • Security Anchor Functionality (SEAF) • Location Services management for regulatory services • Provide transport for Location Services messages between UE and LMF as well as between RAN and LMF • EPS Bearer ID allocation for interworking with EPS • UE mobility event notification

19 Access and Mobility Function (AMF) Context Diagram

20 5 G Service Based Architecture Authentication Server Function (AUSF) Control plane function group Namf Nausf Nsmf AMF AUSF N 1 SMF N 4 N 2 N 3 UE NG Radio Access Network Non-3 GPP Access Network (N 3 IWF functions ) g. Node. B UPF N 9 User plane function DN N 6

21 Authentication Server Function (AUSF) Functionalities • Supports authentication for 3 GPP access and untrusted non 3 GPP access

22 5 G Service Based Architecture Network Slice Selection Function (NSSF) Control plane function group NSSF Nnssf Namf Nausf Nsmf AMF AUSF N 1 SMF N 4 N 2 N 3 UE NG Radio Access Network Non-3 GPP Access Network (N 3 IWF functions ) g. Node. B UPF N 9 User plane function DN N 6

23 Network Slice Selection Function (NSSF) Functionalities • Selecting the set of Network Slice instances serving the UE • Determining the Allowed NSSAI and, if needed, the mapping to the Subscribed S-NSSAIs • Determining the Configured NSSAI and, if needed, the mapping to the Subscribed S-NSSAIs • 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

24 Network Slice Selection Function (NSSF) NSSAI 1 2 3 NSSAI Network Slice Selection Assistance Information 1 3 1 2 3 AMF NSSF • Determining the Allowed NSSAI and Configured NSSAI • Select the appropriate Network Slice instance • Based on Allowed S-NSSAIs, PLMN ID, etc. • Re-allocate AMF if needed Network Slice instances • Common resource • Logically belong to each slice AMF UE 2 NSSAI SMF PCF UPF … DN

25 5 G Service Based Architecture Network Exposure Function (NEF) Control plane function group NSSF Nnssf NEF Nnef Namf Nausf Nsmf AMF AUSF N 1 SMF N 4 N 2 N 3 UE NG Radio Access Network Non-3 GPP Access Network (N 3 IWF functions ) g. Node. B UPF N 9 User plane function DN N 6

26 Network Exposure Function (NEF) Functionalities • Exposes capabilities and events • Secure provision of information from an external application to 3 GPP network • Translation of internal/external information • Control plane parameter provisioning • Packet Flow Description (PFD) management – A PFD is a tuple of protocol, server-side IP and port number

27 Network Exposure Function (NEF) AF 1 AF 2 AF n N 33 • Reference point between NEF and AF API 1 API 2 API 3 NEF SBI between NF and NEF • N 29 interface between NEF and SMF • N 30 interface between NEF and PCF • N 37 interface between NEF and UDR. . . NF 1 . . . API n NEF . . . NF 2 NF n

28 5 G Service Based Architecture Network Repository Function (NRF) Control plane function group NSSF Nnssf NRF NEF Nnrf Nnef Namf Nausf Nsmf AMF AUSF N 1 SMF N 4 N 2 N 3 UE NG Radio Access Network Non-3 GPP Access Network (N 3 IWF functions ) g. Node. B UPF N 9 User plane function DN N 6

29 Network Repository Function (NRF) Functionalities • 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

30 Network Repository Function (NRF) Non-Roaming NRF Network Function Repository Function NF Service Consumer (2) NF Service Discovery NF Service Authorization (3) NF Service Request NF Service Authorization (1) NF Service Registration NF Service Producer Roaming v. NRF Visited Network Function Repository Function (3) NF Service Discovery NF Service Authorization (2) NF Service Discovery NF Service Authorization NF Service Consumer VPLMN h. NRF Home Network Function Repository Function (1) NF Service Registration (4) NF Service Request NF Service Authorization NF Service Producer HPLMN

31 5 G Service Based Architecture Policy Control Function (PCF) Control plane function group NSSF Nnssf NRF NEF PCF Npcf Nnrf Nnef Namf Nausf Nsmf AMF AUSF N 1 SMF N 4 N 2 N 3 UE NG Radio Access Network Non-3 GPP Access Network (N 3 IWF functions ) g. Node. B UPF N 9 User plane function DN N 6

32 Policy Control Function (PCF) • Supports unified policy framework to govern network behaviour • Provides policy rules to Control Plane function(s) to enforce them • Accesses subscription information relevant for policy decisions in a Unified Data Repository (UDR)

33 5 G Service Based Architecture Unified Data Management (UDM) Control plane function group NSSF Nnssf NRF NEF PCF Npcf Nnrf Nnef Namf Nausf N 1 SMF N 4 N 2 N 3 UE NG Radio Access Network Non-3 GPP Access Network (N 3 IWF functions ) Nudm Nsmf AMF AUSF UDM g. Node. B UPF N 9 User plane function DN N 6

34 Unified Data Management (UDM) Functionalities • Generation of 3 GPP AKA Authentication Credentials • User Identification Handling – Storage and management of SUPI for each subscriber in the 5 G system • Support of de-concealment of privacy-protected subscription identifier (SUCI) • Access authorization based on subscription data – Roaming restrictions • UE's Serving NF Registration Management – Storing serving AMF for UE, storing serving SMF for UE's PDU Session • Support to service/session continuity – By keeping SMF/DNN assignment of ongoing sessions • MT-SMS delivery support. • Lawful Intercept Functionality – especially in outbound roaming case where UDM is the only point of contact for LI • Subscription management • SMS management

35 5 G Service Based Architecture Application Function (AF) Control plane function group NSSF Nnssf NRF NEF PCF Npcf Nnrf Nnef Namf Nausf N 1 NG Radio Access Network Non-3 GPP Access Network (N 3 IWF functions ) Naf SMF N 4 N 2 N 3 UE Nudm AF Nsmf AMF AUSF UDM g. Node. B UPF N 9 User plane function DN N 6

36 Application Function (AF) Functionalities • Application influence on traffic routing • Accessing Network Exposure Function • Interacting with the Policy framework for policy control • Application Functions not allowed by the operator to access directly the Network Functions shall use the external exposure framework via the NEF to interact with relevant Network Functions • The functionality and purpose of Application Functions are only defined in this specification with respect to their interaction with the 3 GPP Core Network.

37 Network Slicing NG Radio Access Network Non-3 GPP Access Network (N 3 IWF functions ) Core Network Control Plane User Plane Network Functions Public Land Mobile Network (PLMN)

38 Network Slice Selection Assistance Information (NSSAI) • A set of one or more S-NSSAIs is called the NSSAI • Default Configured NSSAI – Default NSSAI setting by HPLMN • Configured NSSAI 7 6 5 4 3 2 1 0 NSSAI IEI 0 Length of NSSAI contents 1 List of S-NSSAI 1 – Configure by current PLMN – With PLMN identity – Stored in the UE is a set composed of at most 16 S-NSSAIs 2~n • Requested NSSAI – NSSAI provided by the UE to the Serving PLMN during registration • Allowed NSSAI – NSSAI provided by the Serving PLMN during • A Registration procedure, indicating the S-NSSAIs values the UE could use in the Serving PLMN for the current registration area – Stored in the UE is a set composed of at most 8 S-NSSAIs • Rejected NSSAI – NSSAI reject by the Serving PLMN during – With PLMN identity

Single Network Slice Selection Assistance Information (S-NSSAI) • Identifies a Network Slice • Subscribed S-NSSAIs – S-NSSAI based on subscriber information, which a UE is subscribed to use in a PLMN • Mapped S-NSSAI – In roaming scenarios, a mapping S-NSSAI values between HPLMN and Serving PLMN • A Slice/Service type (SST) 7 6 5 4 3 2 1 0 S-NSSAI IEI 0 Length of S-NSSAI contents 1 SST 2 SD Mapped configured SST Mapped configured SD – The expected Network Slice behavior in terms of features and services • A Slice Differentiator (SD) – Optional information that complements the Slice/Service type(s) to differentiate amongst multiple Network Slices of the same Slice/Service type • Network may at any one time serve the UE with only one Network Slice instance associated with this S-NSSAI 3 5 6 7 9 39

40 S-NSSAI values • Standard SST Slice/Service type SST value Characteristics. e. MBB 1 Slice suitable for the handling of 5 G enhanced Mobile Broadband. URLLC 2 Slice suitable for the handling of ultra- reliable low latency communications. MIo. T 3 Slice suitable for the handling of massive Io. T. • Standard SST values and no SD • Standardised SST and an SD • Standardised SST value and no SD • S-NSSAI with a non-standard value – Identifies a single Network Slice within the PLMN with which it is associated – Shall not be used by the UE in access stratum procedures in any PLMN other than the one to which the S-NSSAI is associated

教育部補助 5 G行動寬頻跨校教學聯盟 5 G Network Slicing Registration

42 UE select the slice of the requirement 3 GPP SA 2 #121 國際標準會議報告

43 Network Slice Registration UE g. NB AMF UDM 1. Registration Request 2. AMF Selection 3. Registration Request 4 a. Subscriber Data Request 4 b. Subscriber Data Response 5 a. Network Slice Selection Request 5 b. Network Slice Selection Response 6. AMF Re-allocation 7. Authentication / Security 8. Registration Accept NSSF AUSF

44 Network Slice Registration (Step 1) UE g. NB AMF UDM 1. Registration Request 2. AMF Selection RRCSetup. Complete └ Registration Request 3. Registration Request └ Requested NSSAI 4 a. Subscriber Data Request • If UE has Configured NSSAI and/or Allowed NSSAI for the current PLMN • Select S-NSSAI from Configured NSSAI and Allowed NSSAI 4 b. Subscriber Data Response • If UE has neither Allowed NSSAI nor Configured NSSAI for the current PLMN and has Default Configured NSSAI 5 a. Network Slice Selection Request • Select S-NSSAI from Default Configured NSSAI and Allowed NSSAI • Otherwise 5 b. Network Slice Selection Response • No S-NSSAI • 6. AMF Re-allocation Roaming scenarios • UE shall also provide the Mapped S-NSSAI(s) for the requested NSSAI, if available 7. Authentication / Security 8. Registration Accept NSSF AUSF

45 Network Slice Registration (Step 2) UE g. NB AMF UDM 1. Registration Request 2. AMF Selection 3. Registration Request g. NB select AMF base on Requested NSSAI • If RAN cannot make a choice or no Requested NSSAI 4 a. Subscriber Data Request • Send to default AMF 4 b. Subscriber Data Response 5 a. Network Slice Selection Request 5 b. Network Slice Selection Response 6. AMF Re-allocation 7. Authentication / Security 8. Registration Accept NSSF AUSF

46 Network Slice Registration (Step 3) UE g. NB AMF UDM 1. Registration Request 2. AMF Selection 3. Registration Request 4 a. Subscriber Data Request Initial UE Message └ Registration Request 4 b. Subscriber Data Response • Initial UE Message include Registration Request same as Step 1 5 a. Network Slice Selection Request • g. NB sends the Initial UE Message to the AMF selected in step 2 5 b. Network Slice Selection Response 6. AMF Re-allocation 7. Authentication / Security 8. Registration Accept NSSF AUSF

47 Network Slice Registration (Step 4) UE g. NB AMF UDM NSSF AUSF 1. Registration Request 2. AMF Selection 3. Registration Request UDM Services Type Key └ Nudm_SDM_Get Inputs AMF ID, Slice Selection Subscription data , SUPI Outputs Subscribed S-NSSAI(s) 4 a. Subscriber Data Request 4 b. Subscriber Data Response 5 a. Network Slice Selection Request 5 b. Network Slice Selection Response Conditions • The initial AMF needs UE's subscription information to decide whether to reroute the Registration Request 6. AMF Re-allocation • UE's slice selection subscription information was not provided by old AMF 7. Authentication / Security Actions • Get the Network Slices that the UE subscribes to 8. Registration Accept • In roaming case, it indicates the subscribed network slices applicable to the serving PLMN

48 Network Slice Registration (Step 5) UE g. NB AMF UDM NSSF AUSF 1. Registration Request 2. AMF Selection NSSF Services └ Nnssf_NSSelection_Get 3. Registration Request Inputs • Requested NSSAI • Roaming : [Mapping Of Requested NSSAI] • Subscribed S-NSSAI(s) • With default S-NSSAI indication • TAI (tracking area identity ) of UE • Allowed NSSAI for the other access type (if any) • Roaming : [Mapping of Allowed NSSAI] • PLMN ID of the SUPI 4 a. Subscriber Data Request 4 b. Subscriber Data Response 5 a. Network Slice Selection Request 5 b. Network Slice Selection Response Outputs 6. AMF Re-allocation • AMF Set or list of AMF addresses, • Allowed NSSAI per access type (may be more than one allowed NSSAI) 7. Authentication / Security • Roaming : [Mapping Of Allowed NSSAI] • [NSI ID(s)], [NRF(s)], • [List of rejected (S-NSSAI(s), cause value(s))], 8. Registration Accept • [Configured NSSAI for the Serving PLMN] • Roaming : [ Mapping Of Configured NSSAI] Conditions • AMF cannot serve all the S-NSSAI(s) from the Requested NSSAI permitted by the subscription information Actions • NSSF provide the relevant Network Slice information to AMF

49 Network Slice Registration (Step 6) UE g. NB AMF UDM NSSF 1. Registration Request 2. AMF Selection 3. Registration Request 4 a. Subscriber Data Request 4 b. Subscriber Data Response 5 a. Network Slice Selection Request 5 b. Network Slice Selection Response 6. AMF Re-allocation AMF select a target AMF and executes the re-allocation process 7. Authentication / Security 8. Registration Accept AUSF

50 Network Slice Registration (Step 7) UE g. NB AMF UDM 1. Registration Request 2. AMF Selection 3. Registration Request 4 a. Subscriber Data Request 4 b. Subscriber Data Response • • • 5 a. Network Slice Selection Request AMF send authentication request to AUSF selects a UDM and gets the authentication data from UDM 5 b. Network Slice Selection Response If NAS security context does not exist, the NAS security initiation is performed g. NB stores the security context and acknowledges to the AMF g. NB uses the security context to protect the messages exchanged with the UE 6. AMF Re-allocation 7. Authentication / Security 8. Registration Accept NSSF AUSF

51 Network Slice Registration (Step 8) UE g. NB AMF UDM NSSF AUSF 1. Registration Request 2. AMF Selection 3. Registration Request AMF -> g. NB 4 a. Subscriber Data Request Initial Context Setup Request └ Registration Accept 4 b. Subscriber Data Response └ Old AMF (If g. NB does not participate in AMF Re-allocation ) 5 a. Network Slice Selection Request g. NB -> UE RRCReconfiguration. Complete 5 b. Network Slice Selection Response └ Registration Accept 6. AMF Re-allocation Registration Accept • PDU Session status Allowed NSSAI 7. Authentication • / Security • Roaming : [Mapping Of Allowed NSSAI] • [Configured NSSAI for the Serving PLMN] 8. Registration Accept • Roaming : [Mapping Of Configured NSSAI] • [rejected S-NSSAIs]

52 AMF Re-allocation UE have 3 Network Slice (S-NSSAI) Find a AMF to service Network Slice 1, 2, and 3 Network Slice 1 Network Slice 2 AMF A Network Slice 3 AMF B Initial AMF C Select AMF C as Target AMF to service all Network Slice Re-allocate initial AMF to AMF C

53 AMF Re-allocation - Step 6 at Registration Initial AMF g. NB NRF 6 a. AMF Discovery Request 6 b. AMF Discovery Response 6 c. Registration Request (A) (B) 6 d. Reroute NAS message 6 e. Registration Request Target AMF

54 AMF Re-allocation - Step 6 at Registration (Step a, b) g. NB Initial AMF NRF 6 a. AMF Discovery Request 6 b. AMF Discovery Response NRF Services 6 c. Registration Request (A) └ Nnrf_NFDiscovery Inputs • NF type=AMF • AMF Set 6 d. Reroute NAS message Outputs (B) • list of ( 6 e. Registration Request • AMF pointer, • AMF address • plus additional selection rules and NF capabilities • ) Conditions • If initial AMF does not locally store the target AMF address that use at AMF Re-allocation Actions • Get the AMF information Target AMF

55 AMF Re-allocation - Step 6 at Registration (Step c) g. NB Initial AMF NRF 6 a. AMF Discovery Request 6 b. AMF Discovery Response (A) (B) 6 c. Registration Request 6 d. Reroute NAS message If the initial AMF, based on local policy and subscription information, decides to forward the NAS message to the target AMF directly 6 e. Registration Request AMF Services └ Namf_Communication_N 1 Message. Notify Inputs • Initial AMF ID • SUPI • N 2 terminating point • Registration Request • information from the NSSF Target AMF

56 AMF Re-allocation - Step 6 at Registration (Step d, e) Initial AMF g. NB NRF Target AMF 6 a. AMF Discovery Request 6 b. AMF Discovery Response 6 c. Registration Request (A) If the initial AMF, based on local policy and subscription information, decides to forward the NAS message to the target AMF via (R)AN (B) 6 d. Reroute NAS message 6 e. Registration Request 6 d. Reroute NAS message • Information about the target AMF • Information about the Registration Request message • Information from the NSSF 6 e. Initial UE Message └ Registration Request

教育部補助 5 G行動寬頻跨校教學聯盟 5 G Network Slicing PDU session

58 PDU session (1) UE has 3 Allows S-NSSAI Network Slice 1 (S-NSSAI = 1) Network Slice 2 (S-NSSAI = 2) Network Slice 3 (S-NSSAI = 3) UE can only setup PDU session for Allows S-NSSAI UPF PDU session ID : 10 S-NSSAI = 1 PDU session ID : 11 S-NSSAI = 1 PDU session ID : 12 S-NSSAI = 3 PDU session ID : 13 S-NSSAI = 2 PDU session ID : 14 S-NSSAI = 1 PDU session ID : 15 S-NSSAI = 2 PDU session ID must be unique DN

59 PDU session (2) N 3 N 3 Uplink data classify by UP CL UPF and forward to difference DN N 6 UPF (PSA) I-UPF N 9 UPF (PSA) 1 N 9 I-UPF N 9 UPF (PSA) 2 N 6 UPF (PSA) UPF UP CL N 3 DN N 4 N 6 DN N 4 SMF N 4 N 6 DN DN PSA : PDU session anchor I-UPF : Intermediate PDU UP CL : Uplink Classifier

60 PDU session establishment Non-roaming and Roaming with Local Breakout UE g. NB AMF UPF SMF 1. PDU Session Establishment Request 2. SMF Selection 3. PDU Session Creation 4. UPF Selection 5. Session Establishment 6. PDU Session Message Transfer 7. PDU Session Request 8. Resource Setup 9. PDU Session Response 10. PDU Session Update Request 11. Session Update 12. PDU Session Update Response

PDU session establishment Non-roaming and Roaming with Local Breakout (Step 1) UE g. NB AMF 61 UPF SMF 1. PDU Session Establishment Request 2. SMF Selection NAS Message PDU Session Establishment • S-NSSAI(s) • PDU session ID 3. PDU Session Creation • Allowed NSSAI of the current access type • Requested PDU Session Type • With Mapping of Allowed NSSAI is exist • Initial Request 4. UPF Selection • Optionally • Existing Session • DNN • PDU session Handover 5. Session Establishment • Optionally • Requested SSC mode • PDU Session ID • 5 GSM Capability PCO 6. PDU Session • Message Transfer • Request type SM PDU DN Request Container • Initial Request • Number Of Packet Filters 7. PDU Session Request • Emergency Request • Number of supported packet filters for • 8. Resource Old PDU Session ID signaled Qo. S rules Setup • N 1 SM container (PDU Session Establishment) 9. PDU Session Response 10. PDU Session Update Request 11. Session Update 12. PDU Session Update Response

62 PDU session establishment Non-roaming and Roaming with Local Breakout (Step 2 -1) UE g. NB AMF UPF SMF 1. PDU Session Establishment Request 2. SMF Selection Determines S-NSSAI • If the NAS message does not contain an S-NSSAI • Default S-NSSAI for the requested PDU Session either according to the UE subscription 3. PDU Session Creation 4. UPF Selection 5. Session Establishment Determines DN 6. PDU Session Message Transfer • If the NAS Message contains an S-NSSAI but it does not contain a DNN 7. PDU Session Request • Default DNN for this S-NSSAI if the default 8. Resource Setup DNN is present in the UE's Subscription Information 9. PDU Session Response • otherwise the serving AMF selects a locally 10. PDU Session Update Request configured DNN for this S-NSSAI Determines SMF • If the AMF cannot select an SMF 12. PDU Session Update Response • Reject PDU Session Establishment Request 11. Session Update

63 PDU session establishment Non-roaming and Roaming with Local Breakout (Step 2 -2) UE g. NB AMF UPF SMF 1. PDU Session Establishment Request 2. SMF Selection 3. PDU Session Creation NSSF Services AMF NSSF NRF └ Nnssf_NSSelection_Get 4. UPF Selection Inputs • S-NSSAI from the Allowed NSSAI requested by the UE 2 a. Network Slice Selection Request 5. Session Establishment • PLMN ID of the SUPI • TAI of the UE 2 b. Network Slice Selection Response • the indication that the request is within a procedure 6. PDU Session Message Transfer of PDU Session establishment 7. PDU Session Request 2 c. AMF Discovery Request Output • NRF 8. Resource Setup 2 d. AMF Discovery Response • optionally may return a NSI ID 9. PDU Session Response 10. PDU Session Update Request Conditions • When the serving AMF is not aware of the appropriate NRF to be used to select NFs/services within the corresponding Network Slice instance Actions 12. PDU Session Update Response • NSSF provide the NRF information to AMF 11. Session Update

64 PDU session establishment Non-roaming and Roaming with Local Breakout (Step 2 -2) UE g. NB AMF SMF UPF 1. PDU Session Establishment Request 2. SMF Selection 3. PDU Session Creation NRF Services 4. UPF Selection AMF NSSF NRF └ Nnrf_NFDiscovery Inputs 5. Session Establishment • NF type=SMF 2 a. Network Slice Selection Request • S-NSSAI from the Allowed NSSAI 6. PDU Session Message Transfer • PLMN ID of the SUPI 2 b. Network Slice Selection Response 7. PDU Session Request • DNN • possibly NSI ID 8. Resource Setup 2 c. SMF Discovery Request Outputs • FQDN or IP address of SMF 9. PDU Session Response 2 d. SMF Discovery Response • Set of the discovered SMF instance(s) or Endpoint Address(es) of SMF service instance(s) 10. PDU Session Update Request • Possibly an NSI ID 11. Session Update 12. PDU Session Update Response

PDU session establishment Non-roaming and Roaming with Local Breakout (Step 3) UE g. NB AMF 65 UPF SMF 1. PDU Session Establishment Request 2. SMF Selection 3. PDU Session Creation SMF Services └ Nsmf_PDUSession_Create. SMContext • Request Type : initial request └ Nsmf_PDUSession_Update. SMContext • Request Type : existing PDU Session Nsmf_PDUSession_Update. SMContext 7. PDU Session Request Inputs SUPI, DNN, PDU Session ID, AMF ID, Request Type 8. Resource Setup • S-NSSAI(s) • Allowed NSSAI 9. PDU Session Response • Roaming : [Mapping Of Allowed NSSAI] • N 1 SM container (PDU Session Establishment Request), User location information, Access Type, RAT type, PEI Outputs • Cause, SM Context ID or N 1 SM container (PDU Session Reject (Cause) 4. UPF Selection 5. Session Establishment Nsmf_PDUSession_Create. SMContext Inputs 6. PDU Session Message Transfer • SUPI, DNN, PDU Session ID, AMF ID, Request Type • S-NSSAI(s) • Allowed NSSAI • Roaming : [Mapping Of Allowed NSSAI] • PCF ID, Priority Access, N 1 SM container (PDU Session Establishment Request), User location information, Access Type, PEI, GPSI, UE presence in LADN service area, Subscription For 10. PDU Session Update Request PDU Session Status Notification, DNN Selection Mode, Trace 11. Session Update Requirements Outputs 12. Session Update Response • PDU Cause, SM Context ID or N 1 SM container (PDU Session Reject (Cause)

PDU session establishment Non-roaming and Roaming with Local Breakout (Step 4) UE g. NB AMF SMF 66 UPF 1. PDU Session Establishment Request PDU Session address Allocation 2. SMF Selection • IPv 4 • IPv 6 3. PDU Session Creation • build its link-local address • IPv 4 v 6 4. UPF Selection • build its link-local address • IPv 6 prefix 5. Session Establishment • Unstructured PDU Session Type • N 6 point-to-point tunnelling • based on UDP/IPv 6 6. PDU Session Message Transfer • MAC SMF NSSF NRF 7. PDU Session Request • Ethernet PDU Session 8. Resource NRF Services Setup └ Nnrf_NFDiscovery_Request 9. PDU Session Response Inputs • NF type=UPF • DNN • S-NSSAI • SMF Area Identity Outputs • FQDN or IP address of UPF 4 a. Network Slice Selection Request 4 b. Network Slice Selection Response 10. PDU Session Update Request 4 c. UPF Discovery Request 11. Session Update 4 d. Update UPF Discovery Response 12. PDU Session Response

PDU session establishment Non-roaming and Roaming with Local Breakout (Step 5) UE g. NB AMF 67 UPF SMF 1. PDU Session Establishment Request 2. SMF Selection 3. PDU Session Creation 4. UPF Selection 5. Session Establishment N 4 Session Establishment 6. PDU Session Message Transfer N 4 Session Establishment/Modification Request • Request Type : initial request • Packet detection 7. PDU Session Request N 4 Session Modification • Enforcement • Otherwise • 8. reporting rules Resource Setup • CN Tunnel Conditions 9. PDU Session Response • If CN Tunnel Info is allocated by the SMF • If the Request Type indicates "Existing PDU • Inactivity Timer Session", and the SMF creates CN Tunnel Info, 10. PDU Session Update Request • If the selective User Plane deactivation is required then this step is skipped 11. Session Update Actions N 4 Session Establishment/Modification Response • SMF initiate N 4 Session • CN Tunnel 12. PDU Session Update Response Establishment/Modification procedure with • If CN Tunnel Info is allocated by the UPF 0 each UPF of the PDU Session

PDU session establishment Non-roaming and Roaming with Local Breakout (Step 6) UE g. NB AMF 68 UPF SMF 1. PDU Session Establishment Request 2. SMF Selection 3. PDU Session Creation 4. UPF Selection 5. Session Establishment 6. PDU Session Message Transfer AMF Services 7. PDU Session Request └ Namf_Communication_N 1 N 2 Message. Transfer 8. Resource Setup Inputs • • • PDU Session ID 9. PDU Session Response N 1 SM container (PDU Session Establishment Accept (Qo. S Rule(s) and Qo. S Flow level Qo. S parameters if needed for the Qo. S Flow(s) associated with the Qo. S rule(s), selected SSC mode, S-NSSAI(s), DNN, allocated IPv 4 address, 10. PDU Session Update Request interface identifier, Session-AMBR, selected PDU Session Type, Reflective Qo. S Timer (if available), P-CSCF address(es), 11. Session Update [Always-on PDU Session])) N 2 SM information (PDU Session ID, QFI(s), Qo. S Profile(s), CN Tunnel Info, S-NSSAI from the Allowed NSSAI, Session 12. PDU Session Update Response AMBR, PDU Session Type, User Plane Security Enforcement information, UE Integrity Protection Maximum Data Rate)

PDU session establishment Non-roaming and Roaming with Local Breakout (Step 7) UE g. NB AMF 69 UPF SMF 1. PDU Session Establishment Request 2. SMF Selection 3. PDU Session Creation 4. UPF Selection 5. Session Establishment 6. PDU Session Message Transfer 7. PDU Session Request 8. Resource Setup N 2 PDU Session Request • N 2 SM information 9. PDU Session Response • NAS message 10. PDU Session Update Request • PDU Session ID, • N 1 SM container (PDU Session Establishment Accept) 12. PDU Session Update Response 11. Session Update

PDU session establishment Non-roaming and Roaming with Local Breakout (Step 8) UE g. NB AMF 70 UPF SMF 1. PDU Session Establishment Request 2. SMF Selection 3. PDU Session Creation 4. UPF Selection 5. Session Establishment 6. PDU Session Message Transfer 7. PDU Session Request 8. Resource Setup • • • 9. PDU Session Response Setup g. NB for PDU session • g. NB allocates (R)AN N 3 t. Tunnel Info for the PDU Session 10. PDU Session Update Request • QFI setting g. NB Send RRC Connection Reconfiguration to UE RAN Forwards the NAS message to UE • PDU Session ID 12. PDU Session Update Response • N 1 SM container (PDU Session Establishment Accept) 11. Session Update

PDU session establishment Non-roaming and Roaming with Local Breakout (Step 9) UE g. NB AMF 71 UPF SMF 1. PDU Session Establishment Request 2. SMF Selection 3. PDU Session Creation 4. UPF Selection 5. Session Establishment 6. PDU Session Message Transfer 7. PDU Session Request 8. Resource Setup 9. PDU Session Response After this step, uplink channel is sucess. UE can be start to sent Uplink Data 10. PDU Session Update Request N 2 PDU Session Response 11. Session Update • PDU Session ID • Cause 12. PDU Session Update Response • N 2 SM information (PDU Session ID, AN Tunnel Info, List of accepted/rejected QFI(s), User Plane Enforcement Policy Notification)

PDU session establishment Non-roaming and Roaming with Local Breakout (Step 10) UE g. NB AMF 72 UPF SMF 1. PDU Session Establishment Request 2. SMF Selection 3. PDU Session Creation 4. UPF Selection 5. Session Establishment 6. PDU Session Message Transfer 7. PDU Session Request 8. Resource Setup 9. PDU Session Response SMF Services └ Nsmf_PDUSession_Update. SMContext Request Inputs • N 2 SM information • Request Type 10. PDU Session Update Request 11. Session Update If the list of rejected QFI(s) is included in N 2 SM information, the SMF shall release the rejected QFI(s) 12. PDU Session Update Response

PDU session establishment Non-roaming and Roaming with Local Breakout (Step 11) UE g. NB AMF 73 UPF SMF 1. PDU Session Establishment Request 2. SMF Selection 3. PDU Session Creation 4. UPF Selection 5. Session Establishment 6. PDU Session Message Transfer 7. PDU Session Request 8. Resource Setup 9. PDU Session Response N 4 Session Request 10. PDUModification Session Update Request • AN Tunnel Info N 4 Session Modification Response After this step, the UPF delivers any down-link packets to the 12. PDU Session Update Response UE that may have been buffered for this PDU Session. 11. Session Update

PDU session establishment Non-roaming and Roaming with Local Breakout (Step 12) UE g. NB AMF 74 UPF SMF 1. PDU Session Establishment Request 2. SMF Selection 3. PDU Session Creation 4. UPF Selection 5. Session Establishment 6. PDU Session Message Transfer 7. PDU Session Request 8. Resource Setup 9. PDU Session Response SMF Services └ Nsmf_PDUSession_Update. SMContext Response Outputs • Cause 10. PDU Session Update Request 11. Session Update 12. PDU Session Update Response

75 Home-routed Roaming UE visited to VPLMN using Home-routed Roaming AMF VPLMN v. NSSF h. NSSF v. NRF h. NRF v. SMF h. SMF v. UPF h. UPF In Home-routed Roaming • Data Network connection to PLMN • PDU session setup to HPLMN DN

76 PDU session establishment Home-routed Roaming UE g. NB AMF v. UPF v. SMF VPLMN 1. PDU Session Establishment Request h. UPF h. SMF HPLMN 2. SMF Selection 3. PDU Session Create Select v. UPF 2. UPF Selection 4. Session Establishment 5. PDU Session Create Request Select h. UPF 6. UPF Selection 7. Session Establishment 8. PDU Session Create Response 9. PDU Session Message Transfer 10. PDU Session Request 11. Resource Setup 12. PDU Session Response 13. PDU Session Update Request 14. Session Update 15. PDU Session Update Response

77 PDU session establishment Home-routed Roaming UE g. NB AMF v. UPF v. SMF VPLMN 1. PDU Session Establishment Request h. UPF h. SMF HPLMN 2. SMF Selection 3. PDU Session Create AMF Select v. UPF v. NSSF 2. UPF Selection v. NRF h. NSSF 4. Session Establishment 2 a. Network Slice Selection Request 2 c. Network Slice Selection Request 5. PDU Session Create Request Select 2 d. Network Slice Selection Response 2 e. Network Slice Selection Response 6. UPF Selection 2 f. AMF Discovery Request h. NRF h. UPF 7. Session Establishment 8. PDU Session Create Response 2 g. AMF Discovery Request 9. PDU Session Message Transfer 10. PDU Session Request 11. Resource Setup 2 i. AMF Discovery Response 12. PDU Session Response 13. PDU Session Update Request 14. Session Update 15. PDU Session Update Response 2 h. AMF Discovery Response

教育部補助 5 G行動寬頻跨校教學聯盟 5 G Network Slicing Handover

79 Xn based inter NG-RAN handover AMF / UPF NG NG Xn Xn Xn Without Xn interface Xn Cannot do Xn based handover Xn

80 Xn based inter NG-RAN handover Without UPF re-allocation SMF Hand over a UE from a source NG-RAN to target NG-RAN Source NG-RAN have Xn connectivity to the target NG-RAN AMF is unchanged SMF decides to keep the existing UPF and I -UPF I-UPF DN UPF Xn Connectivity Target NG-RAN Source NG-RAN Handover

81 Xn based inter NG-RAN handover Preparation and Execution between g. NB UE Source g. NB Target g. NB UE in RRC_CONNECTED with n slice configured at NAS level and with m PDU sessions active Handover Preparation to Target g. NB Handover Request (All PDU Session with S-NSSAI) Slice Aware Admission Control Handover Response (List of Accepted and Rejected PDU Session) Handover Execution

82 Xn based inter NG-RAN handover Without UPF re-allocation UE Source g. NB Target g. NB AMF UPF SMF Handover Preparation Handover Execution Forwarding of data 1. Path Switch Request 2. PDU Session Update Request 3. Session Modification 4 a. End marker 4 b. End marker 5. PDU Session Update Response 6. Path Switch Response 7. Release Resources

83 Xn based inter NG-RAN handover Without UPF re-allocation (Step 1) UE Source g. NB Target g. NB AMF SMF UPF Handover Preparation Handover Execution Forwarding of data 1. Path Switch Request 2. PDU Session Update Request N 2 Path Switch Request • List of PDU Sessions To Be Switched with N 2 SM Information 3. Session Modification • Include the list of accepted Qo. S Flows • List of PDU Sessions Rejected with for each PDU Session N 2 SM Information including a rejection Cause 4 a. End marker • None of the Qo. S Flows of a PDU Session are accepted by the Target g. NB • Corresponding network slice is not supported in the Target g. NB 4 b. End marker • UE Location Information • Selected PLMN ID 5. PDU Session Update Response S-NSSAI is introduced as part of the PDU Switch session. Response information 6. Path 7. Release Resources

84 Xn based inter NG-RAN handover Without UPF re-allocation (Step 2) UE Source g. NB Target g. NB AMF SMF UPF Handover Preparation Handover Execution Forwarding of data 1. Path Switch Request 2. PDU Session Update Request 3. Session Modification SMF Services └ Nsmf_PDUSession_Update. SMContext Request 4 a. End marker Inputs 4 b. End marker • PDU Session To Be Switched with N 2 SM Information (Secondary RAT usage data, Handover Flag) • PDU Sessions Rejected with a rejection Cause 5. PDU Session Update Response • UE Location Information • UE presence in LADN service area 6. Path Switch Response 7. Release Resources

85 Xn based inter NG-RAN handover Without UPF re-allocation (Step 3) UE Source g. NB Target g. NB AMF UPF SMF Handover Preparation Handover Execution Forwarding of data 1. Path Switch Request 2. PDU Session Update Request 3. Session Modification Modify N 3 tunnel (g. NB <-> UPF) 4 a. End marker N 4 Session 4 b Modification Request • AN Tunnel Info 5. PDU Session Update Response • CN Tunnel Info • UPF used for connection to Target g. NB and connection to Source g. NB 6. Path Switch Response • CN Tunnel Info (on N 3) of UPF need be re-allocated N 4 Session Modification Response 7. Release Resources • CN Tunnel Info • N 3 (R)AN tunnel information is released

86 Xn based inter NG-RAN handover Without UPF re-allocation (Step 4) UE Source g. NB Target g. NB AMF UPF SMF Handover Preparation Handover Execution Forwarding of data 1. Path Switch Request 2. PDU Session Update Request 3. Session Modification 4 a. End marker 4 b. End marker 5. PDU Session Update Response UPF sends one or more "end marker" packets for each N 3 tunnel on the old path immediately after switching the path 6. Path Switch Response The UPF 7. starts sending downlink packets to the Target g. NB Release Resources

87 Xn based inter NG-RAN handover Without UPF re-allocation (Step 5) UE Source g. NB Target g. NB AMF UPF SMF Handover Preparation Handover Execution Forwarding of data 1. Path Switch Request 2. PDU Session Update Request 3. Session Modification 4 a. End marker 4 b. End marker SMF Services └ Nsmf_PDUSession_Update. SMContext Response Outputs 6. Path Switch Response • CN Tunnel Info • Used to setup N 3 tunnel 7. Release Resources • Without including the CN Tunnel Info which user plane resources are deactivated or released 5. PDU Session Update Response

88 Xn based inter NG-RAN handover Without UPF re-allocation (Step 6) UE Source g. NB Target g. NB AMF UPF SMF Handover Preparation Handover Execution Forwarding of data 1. Path Switch Request 2. PDU Session Update Request 3. Session Modification 4 a. End marker 4 b. End marker 5. PDU Session Update Response 6. Path Switch Response 7. Release Resources N 2 Path Switch Response • N 2 SM Information • Failed PDU Sessions

89 Xn based inter NG-RAN handover Without UPF re-allocation (Step 7) UE Source g. NB Target g. NB AMF UPF SMF Handover Preparation Handover Execution Forwarding of data 1. Path Switch Request 2. PDU Session Update Request 3. Session Modification 4 a. End marker 4 b. End marker 5. PDU Session Update Response 6. Path Switch Response 7. Release Resources Target g. NB confirms success of the handover Target g. NB triggers the release of resources with the Source g. NB

90 Xn based inter NG-RAN handover With insertion of intermediate UPF Hand over a UE from a source NG-RAN to target NG-RAN Source NG-RAN have Xn connectivity to the target NG-RAN AMF is unchanged SMF decides that insertion of a new additional I-UPF is needed UPF (PSA) SMF DN I-UPF Xn Connectivity Target NG-RAN Source NG-RAN Handover

91 Xn based inter NG-RAN handover With insertion of intermediate UPF UE Source g. NB Target g. NB AMF SMF UPF (PSA) new I-UPF Handover Preparation Handover Execution Forwarding of data 1. Path Switch Request 2. PDU Session Update Request 3. I-UPF selection 4. Session Modification 5. Session Establishment 6. Session Modification 7 a. End marker 7 b. End marker 8. PDU Session Update Response 9. Path Switch Response 10. Release Resources

92 Xn based inter NG-RAN handover With insertion of intermediate UPF (Step 3) UE Source g. NB Target g. NB AMF SMF UPF (PSA) new I-UPF Handover Preparation Handover Execution Forwarding of data 1. Path Switch Request 2. PDU Session Update Request 3. I-UPF selection 4. Session Modification SMF selects a new UPF to act as intermediate UPF for the PDU Session 5. Session Establishment 6. Session Modification 7 a. End marker 7 b. End marker 8. PDU Session Update Response 9. Path Switch Response 10. Release Resources

93 Xn based inter NG-RAN handover With insertion of intermediate UPF (Step 4) UE Source g. NB Target g. NB AMF SMF UPF (PSA) new I-UPF Handover Preparation Handover Execution Forwarding of data 1. Path Switch Request 2. PDU Session Update Request 3. I-UPF selection Conditional • Different CN Tunnel Info need be used • CN Tunnel Info is allocated by the UPF Modify and Get N 9 tunnel by UPF (UPF <-> UPF) • Uplink 4. Session Modification 5. Session Establishment 6. Session Modification N 4 Session Modification 7 b. End. Request marker • CN Tunnel 8. PDU Session Update Response N 4 Session Modification Response 9. Path Switch Response • CN Tunnel Info • UPF (PSA) allocates CN Tunnel Info (on N 9) of UPF (PSA) 10. Release Resources • Provides CN Tunnel Info (on N 9) to the SMF 7 a. End marker

94 Xn based inter NG-RAN handover With insertion of intermediate UPF (Step 5) UE Source g. NB Target g. NB AMF SMF UPF (PSA) new I-UPF Handover Preparation Handover Execution Forwarding of data 1. Path Switch Request 2. PDU Session Update Request 3. I-UPF selection Establish N 9 tunnel by UPF(UPF <-> UPF) • Uplink and Downlink 4. Session Modification 5. Session Establishment N 4 Session Establishment Request 6. Session Modification • Target g. NB Tunnel Info • CN Tunnel Info of the PDU Session Anchor (PSA) 7 a. End marker • Used to setup N 9 tunnel • If the CN Tunnel Info of the I-UPF is allocated by the SMF, 7 b. End marker provides the UL and DL CN Tunnel Info of I-UPF to the I-UPF 8. PDU Session Update Response N 4 Session Establishment Response 9. Path Switch Response • CN Tunnel • If the CN Tunnel Info of the I-UPF is allocated by the UPF, the 10. Release Resources UL and DL CN Tunnel Info of I-UPF is sent to the SMF

95 Xn based inter NG-RAN handover With insertion of intermediate UPF (Step 6) UE Source g. NB Target g. NB AMF SMF UPF (PSA) new I-UPF Handover Preparation Handover Execution Forwarding of data 1. Path Switch Request 2. PDU Session Update Request 3. I-UPF selection Modify N 9 tunnel by SMF (UPF <-> UPF) • Downlink • Uplink and Downlink • If CN Tunnel Info is allocated by the SMF (without Step 4) N 4 Session Modification Request • DL CN Tunnel Info of the I-UPF 7 b. End marker • UL CN Tunnel Info N 4 Session Modification Response 4. Session Modification 5. Session Establishment 6. Session Modification 7 a. End marker 8. PDU Session Update Response 9. Path Switch Response PDU Session Anchor starts sending downlink packets to the Target g. NB 10. Release Resources via I-UPF

96 Xn based inter NG-RAN handover With re-allocation of intermediate UPF Hand over a UE from a source NG-RAN to target NG-RAN Source NG-RAN have Xn connectivity to the target NG-RAN SMF AMF is unchanged SMF decides that the I -UPF is to be changed Source I-UPF Target I-UPF (PSA) Xn Connectivity Target NG-RAN Source NG-RAN Handover DN

97 Xn based inter NG-RAN handover With re-allocation of intermediate UPF UE Source g. NB Target g. NB SMF / v. SMF AMF UPF (PSA) h. SMF Target I-UPF Handover Preparation Handover Execution Forwarding of data 1. Path Switch Request 2. PDU Session Update Request 3. I-UPF selection 4. Session Modification 5. Session Establishment 6. Session Modification 7. PDU Session Update 8 a. End marker 9 b. End marker 10. PDU Session Update Response 11. Path Switch Response 12. Release Resources 13. Session Release Source I-UPF

Xn based inter NG-RAN handover With re-allocation of intermediate UPF (Step 6, 7) UE Source g. NB Target g. NB AMF SMF / v. SMF h. SMF UPF (PSA) Target I-UPF Handover Preparation Handover Execution Forwarding of data 1. Path Switch Request 2. PDU Session Update Request 3. I-UPF selection 4. Session Modification 5. Session Establishment Re-allocation of UPF (Non-roaming and Roaming with Local 6. Session Modification Breakout ) • Do step 6 and skip step 7 7. PDU Session Update • SMF send Session Modification to modify the PDU Session 8 a. End marker • Modify N 9 tunnel. End (In marker Re-allocation 9 b of v. UPF case of home routed 10. roaming) PDU Session Update Response • Do step 7 and skip step 6 11. Path Switch Response • UPF (PSA) allocate at HPLMN 12. Release Resources • v. SMF sent PDU Session Update to notify the h. SMF to 13. Session Release modify PDU Session 98 Source I-UPF

Xn based inter NG-RAN handover With re-allocation of intermediate UPF (Step 13) UE Source g. NB Target g. NB SMF / v. SMF AMF h. SMF UPF (PSA) Target I-UPF Handover Preparation Handover Execution Forwarding of data 1. Path Switch Request 2. PDU Session Update Request 3. I-UPF selection 4. Session Modification 5. Session Establishment 6. Session Modification 7. PDU Session Update The timer is started in step 5 if the source UPF is not the PSA UPF 8 a. End marker When this timer is expired, the SMF initiates Source UPF Release procedure 9 b. End marker 10. PDU Session Update Response N 4 Session Release Request 11. Path Switch Response • Release Cause 12. Release Resources N 4 Session Release Response 13. Session Release 99 Source I-UPF

100 Inter NG-RAN node N 2 based handover New radio conditions or load balancing SMF No Xn connectivity to the target NG-RAN Error indication from the target NG-RAN after an unsuccessful Xn-based handover Target AMF Source AMF may be change at handover If AMF changed • SMF hold any signalling messages targeted towards AMF until handover completed, cancelled or expiry of the guard timer in handover preparation phase SMF decides that the I-UPF or UPF (PSA) is to be changed Source I-UPF Target I-UPF (PSA) Xn Connectivity (May be not exist) Target NG-RAN Source NG-RAN Handover DN

101 Inter NG-RAN node N 2 based handover Preparation phase SMF Preparing the control plane channel for handover • Determine AMF and I-UPF Target AMF Source g. NB detects that the UE is being Handover, then it notify Source AMF to handover the UE Source I-UPF Target I-UPF (PSA) Setup Uplink Data plane channel Xn Connectivity (May be not exist) Target NG-RAN Source NG-RAN Handover DN

102 Inter NG-RAN node N 2 based handover Preparation phase UE Source g. NB Target g. NB Source AMF Target I-UPF SMF / v. SMF Source I-UPF (PSA) / h. SMF 1. Handover Request 2. Target AMF Selection 3. Communication Create Request 4. PDU Session Update Request 5. UPF Selection 6 b. Session Establishment 6 a. Session Modification 7. PDU Session Update Response 8 a. Handover Request 8 b. Handover Response 9. PDU Session Update Request 10. Session Modification 11. PDU Session Update Response 12. Communication Create Response

103 Inter NG-RAN node N 2 based handover Preparation phase (Step 1) UE Source g. NB Target g. NB Source AMF Target I-UPF SMF / v. SMF Source I-UPF (PSA) / h. SMF 1. Handover Request 2. Target AMF Selection Handover Reqest 3. Communication Create Request • Target ID • Includes the selected PLMN ID 4. PDU Session Update Request • Source to Target transparent container • SM N 2 info list 5. UPF Selection • PDU Session IDs 6 a. Session Modification 6 b. Session Establishment • intra system handover indication 7. PDU Session Update Response 8 a. Handover Request 8 b. Handover Response 9. PDU Session Update Request 10. Session Modification 11. PDU Session Update Response 12. Communication Create Response

104 Inter NG-RAN node N 2 based handover Preparation phase (Step 2) UE Source g. NB Target g. NB Source AMF Target I-UPF SMF / v. SMF Source I-UPF (PSA) / h. SMF 1. Handover Request 2. Target AMF Selection 3. Communication Create Request Conditional 4. PDU Session Update Request When the S-AMF can't serve the UE anymore, the Source AMF selects the Target AMF 5. UPF Selection The AMF selection functionality in the 5 G-AN may consider the following factors for selecting the AMF Set • AMF Region ID and AMF Set ID derived from GUAMI 6 b. Session Establishment 6 a. Session Modification • Requested NSSAI • Local operator policies 7. PDU Session Update Response AMF Set ID 8 a. Handover Request • locally configured on AMF 8 b. Handover Response • Utilizing the NRF to discover the AMF instances 9. PDU Session Update Request 10. Session Modification 11. PDU Session Update Response 12. Communication Create Response

105 Inter NG-RAN node N 2 based handover Preparation phase (Step 3) UE Source g. NB Target g. NB Source AMF Target I-UPF SMF / v. SMF Source I-UPF (PSA) / h. SMF 1. Handover Request 2. Target AMF Selection 3. Communication Create Request AMF Services └ Namf_Communication_Create. UEContext Request 4. PDU Session Update Request Conditional 5. UPF Selection • When the Source AMF selects the Target AMF to serve 6 a. Session Modification 6 b. Session Establishment the UE, Source AMF initiates Handover resource allocation to the target AMF Inputs • N 2 Information • Target ID 7. PDU Session Update Response • Source to Target transparent container • SM N 2 information list 8 a. Handover Request • PDU Session IDs 8 b. Handover Response • Service area restriction • UE context information 9. PDU Session Update Request • SUPI • Allowed NSSAI for each Access Type if available 10. Session Modification • Tracing Requirements • List of PDU Session IDs along with the corresponding SMF information 11. PDU Session Update Response • Corresponding S-NSSAI(s) • PCF ID(s) 12. Communication Create Response • DNN

106 Inter NG-RAN node N 2 based handover Preparation phase (Step 4) UE Source g. NB Target g. NB Source AMF Target I-UPF SMF / v. SMF Source I-UPF (PSA) / h. SMF 1. Handover Request 2. Target AMF Selection 3. Communication Create Request 4. PDU Session Update Request SMF Services └ Nsmf_PDUSession_Update. SMContext Request Inputs • PDU Session ID 8 a. Handover Request • Target ID • T-AMF ID 8 b. Handover Response • N 2 SM Info (Secondary RAT Usage Data) 5. UPF Selection 6 b. Session Establishment 6 a. Session Modification 7. PDU Session Update Response 9. PDU Session Update Request Target AMF does not invoke this message for this PDU Session if the S-NSSAI associated with PDU Session is not available in the Target AMF 10. Session Modification In the case of home routed roaming scenario, the SMF is v. SMF 11. PDU Session Update Response 12. Communication Create Response

107 Inter NG-RAN node N 2 based handover Preparation phase (Step 5) UE Source g. NB Target g. NB Source AMF Target I-UPF SMF / v. SMF Source I-UPF (PSA) / h. SMF 1. Handover Request 2. Target AMF Selection 3. Communication Create Request 4. PDU Session Update Request 5. UPF Selection 6 b. Session Establishment 6 a. Session Modification Based on the Target ID, SMF checks if N 2 Handover for the indicated PDU Session can be accepted 7. PDU Session Update Response If UE has moved out of the service area of the UPF connecting to NG-RAN, SMF 8 a. Handover Request selects a new intermediate UPF 8 b. Handover Response 9. PDU Session Update Request 10. Session Modification 11. PDU Session Update Response 12. Communication Create Response

108 Inter NG-RAN node N 2 based handover Preparation phase (Step 6) UE Source g. NB Target g. NB Source AMF Target I-UPF SMF / v. SMF Source I-UPF (PSA) / h. SMF 1. Handover Request 2. Target AMF Selection 3. Communication Create Request 4. PDU Session Update Request 5. UPF Selection Conditional • If the SMF selects a new I-UPF or reallocate I-UPF for the PDU Session 6 b. Session Establishment 6 a. Session Modification 7. PDU Session Update Response SMF -> UPF (PSA) Modify N 9 tunnel (UPF <-> UPF)8 a. Handover Request • Uplink 8 b. Handover Response SMF -> Target UPF Establish N 9 tunnel (UPF <-> UPF) • Uplink N 4 Session Modification Request • CN Tunnel Info (on N 9) • If the CN Tunnel Info is allocated by the SMF N 4 Session Modification Response • CN Tunnel Info (on N 9) • If the CN Tunnel Info is allocated by the UPF N 4 PDU Session 9. Session. Establishment Update Request • CN Tunnel Info (on N 9) of UPF (PSA) for this PDU Session 10. Session Modification N 4 Session Establishment Response • DL CN Tunnel 11. Session Update Response • PDU UL CN Tunnel 12. Communication Create Response

109 Inter NG-RAN node N 2 based handover Preparation phase (Step 7) UE Source g. NB Target g. NB Source AMF Target I-UPF SMF / v. SMF Source I-UPF (PSA) / h. SMF 1. Handover Request 2. Target AMF Selection 3. Communication Create Request 4. PDU Session Update Request 5. UPF Selection 6 b. Session Establishment SMF Services └ Nsmf_PDUSession_Update. SMContext Response 6 a. Session Modification 7. PDU Session Update Response 8 a. Handover Request Outputs 8 b. Handover Response • PDU Session ID • N 2 SM Information 9. PDU Session Update Request • Include if N 2 handover for the PDU Session is accepted • Only include regarding the PDU Session If the SMF is notified that the UE is only reachable for regulatory 10. Session Modification prioritized services • Avoid establishment of radio resources at the target NG-RAN 11. PDU Session Update Response • Reason for non-acceptance • Include if N 2 handover for the PDU Session is not accepted 12. Communication Create Response

110 Inter NG-RAN node N 2 based handover Preparation phase (Step 8) UE Source g. NB Target g. NB Source AMF Target I-UPF SMF / v. SMF Source I-UPF (PSA) / h. SMF 1. Handover Request 2. Target AMF Selection 3. Communication Create Request 4. PDU Session Update Request 5. UPF Selection 6 b. Session Establishment 6 a. Session Modification 7. PDU Session Update Response 8 a. Handover Request 8 b. Handover Response Handover Request • Source to Target transparent container • N 2 MM Information • N 2 SM Information list • Tracing Requirements Handover Request Response 9. PDU Session Update Request • Target to Source transparent container 10. Session Modification • List Of PDU Sessions to Hand-over • With for each PDU Session N 2 SM information 11. PDU Session Update Response • List Of PDU Sessions failed to be setup • with for each PDU Session N 2 SM information containing the 12. Communication Create Response reason for failure

111 Inter NG-RAN node N 2 based handover Preparation phase (Step 9) UE Source g. NB Target g. NB Source AMF Target I-UPF SMF / v. SMF Source I-UPF (PSA) / h. SMF 1. Handover Request 2. Target AMF Selection 3. Communication Create Request 4. PDU Session Update Request 5. UPF Selection 6 b. Session Establishment 6 a. Session Modification 7. PDU Session Update Response SMF Services 8 a. Handover Request └ Nsmf_PDUSession_Update. SMContext Request 8 b. Handover Response Inputs • PDU Session ID • N 2 SM response received from Target g. NB • Receive from step 8 9. PDU Session Update Request 10. Session Modification 11. PDU Session Update Response If no new T-UPF is selected, SMF stores the N 3 tunnel info of Target g. NB from the N 2 SM response 12. Communication Create Response

112 Inter NG-RAN node N 2 based handover Preparation phase (Step 10) Source Target UE g. NB Modify N 3 tunnel (g. NB <-> UPF) • Uplink 1. Handover Request Source AMF Target I-UPF SMF / v. SMF Source I-UPF (PSA) / h. SMF 2. Target AMF Selection SMF to Target I-UPF If the SMF selected a Target I-UPF 3. Communication Create Request N 4 Session Modification Request 4. PDU Session Update Request • Target g. NB SM N 3 forwarding Information list • Indication to allocate DL forwarding tunnel(s) for 5. UPF Selection indirect forwarding • Use for data forwarding at Execution phase 6 a. Session Modification 6 b. Session Establishment N 4 Session Modification Response • Target I-UPF SM N 3 forwarding Information list 7. PDU Session Update Response SMF to Source I-UPF 8 a. Handover Request N 4 Session Modification Request • Target g. NB SM N 3 forwarding Information list 8 b. Handover Response • If the UPF is not re-allocated • Target I-UPF SM N 3 forwarding Information list 9. PDU Session Update Request • If the UPF is re-allocated 10. Session Modification • Indication to allocate DL forwarding tunnel(s) for indirect forwarding • Use for data forwarding at Execution phase 11. PDU Session Update Response N 4 Session Modification Response 12. Communication Create Response • Source I-UPF SM N 3 forwarding Information list

113 Inter NG-RAN node N 2 based handover Preparation phase (Step 11) UE Source g. NB Target g. NB Source AMF Target I-UPF SMF / v. SMF Source I-UPF (PSA) / h. SMF 1. Handover Request 2. Target AMF Selection 3. Communication Create Request 4. PDU Session Update Request 5. UPF Selection 6 b. Session Establishment 6 a. Session Modification 7. PDU Session Update Response 8 a. Handover Request 8 b. Handover Response SMF Services └ Nsmf_PDUSession_Update. SMContext Response Outputs • N 2 SM Information 9. PDU Session Update Request 10. Session Modification 11. PDU Session Update Response 12. Communication Create Response

114 Inter NG-RAN node N 2 based handover Preparation phase (Step 12) UE Source g. NB Target g. NB Source AMF Target I-UPF SMF / v. SMF Source I-UPF (PSA) / h. SMF 1. Handover Request 2. Target AMF Selection 3. Communication Create Request 4. PDU Session Update Request AMF Services 5. UPF Selection └ Namf_Communication_Create. UEContext Response 6 b. Session Establishment 8 a. Handover Request 8 b. Handover Response 6 a. Session Modification Outputs • N 2 information necessary for S-AMF to send 7. PDU Session Update Response Handover Command to S-RAN • Including Target to Source transparent container (From Step 8 b) • PDU Sessions failed to be setup list 9. • PDUN 2 SM information (From Step 11) Session Update Request • N 3 DL forwarding Information • PCF ID 10. Session Modification 11. PDU Session Update Response 12. Communication Create Response

115 Inter NG-RAN node N 2 based handover Execution phase Release the old and temporary channel SMF Target AMF Source I-UPF Target I-UPF (PSA) Setup Downlink Data plane Notify UE to handover Xn Connectivity (May be not exist) Target NG-RAN Source NG-RAN Handover DN

116 Inter NG-RAN node N 2 based handover Execution phase UE Source g. NB Target g. NB Source AMF Target I-UPF SMF / v. SMF Source I-UPF (PSA) / h. SMF 1. Handover Command 2. Status Transfer 3. Handover Confirm 4. Handover Notify 5. Communication Notify 6. PDU Session Release 7. PDU Session Update Request 8 a. Session Modification 8 b. Session Modification 9. Session Modification 10. PDU Session Update Response 11. Registration Procedure 12 b. UE Context Release Command 12 c. Session Modification 12 a. Session Release

117 Inter NG-RAN node N 2 based handover Execution phase (Step 1) UE Source g. NB Target g. NB Source AMF Target I-UPF SMF / v. SMF Source I-UPF (PSA) / h. SMF 1. Handover Command Source AMF -> Source g. NB 2. Status Transfer Handover Command 3. Handover Confirm • Target to Source transparent container 4. Handover Notify • List Of PDU Sessions to be handed-over • With N 2 SM information containing information 5. Communication Notify • Received from Target g. NB during the handover preparation phase • Direct forwarding : Include T-RAN SM N 3 forwarding info list 6. PDU Session Release • Indirect data forwarding : Include S-UPF SM N 3 forwarding info list • List Of PDU Sessions failed to be setup 7. PDU Session Update Request Source g. NB -> UE 8 a. Session Modification 8 b. Session Modification Handover Command • UE container 9. Session Modification • UE part of the Target to Source transparent container • Sent transparently from T-RAN via AMF to S-RAN and is provided to the UE by the S-RAN 10. PDU Session Update Response 11. Registration Procedure 12 b. UE Context Release Command 12 c. Session Modification 12 a. Session Release

118 Inter NG-RAN node N 2 based handover Execution phase (Step 2 -1) UE Source g. NB Target g. NB Source AMF Target I-UPF SMF / v. SMF Source I-UPF (PSA) / h. SMF If there is an AMF relocation 1. Handover Command 2 a. Uplink RAN Status Transfer message • PDCP PDU Status 2 b. AMF Services └ Namf_Communication_N 1 N 2 Message. Transfer 4. Handover Notify 2 c. Downlink RAN Status Transfer message 5. Communication Notify • PDCP PDU Status 2. Status Transfer 3. Handover Confirm Source g. NB 6. PDU Session Release Target Source Target g. NB AMF I-UPF 7. PDU Session Update Request 2 a. Uplink RAN Status Transfer 8 a. Session Modification 2 b. Communication Transfer Source I-UPF (PSA) / h. SMF 8 b. Session Modification 9. Session Modification 2 c. Downlink RAN Status Transfer 10. PDU Update Response 2 d. Session Downlink User Plane Data 2 e. Direct data forwarding 11. Registration Procedure 2 f. Indirect data forwarding 12 c. Session Modification 12 a. Session Release 12 b. UE Context Release Command 2 g. Uplink User Plane Data

119 Inter NG-RAN node N 2 based handover Execution phase (Step 2 -2) UE Source g. NB Target g. NB Source AMF Target I-UPF SMF / v. SMF Source I-UPF (PSA) / h. SMF 1. Handover Command • • Source g. NB should start forwarding Data Plane data to 2. Status Transfer Target g. NB 2 e. Direct data forward 3. Handover Confirm • If Source g. NB is allowed to send data direct to Downlink User Plane Data send from UPF(PSA) to Source Target g. NB 4. Handover Notify I-UPF to Source g. NB 2 f. Indirect data forward Uplink User Plane Channel from Target g. NB to Target I 5. Communication Notify • Setup at Preparation phase UPF and UPF(PSA) is success UE should not send Uplink data to Target g. NB and receive Downlink data from Target g. NB since handover process for UE is not finished Source g. NB 6. PDU Session Release Target Source Target g. NB AMF I-UPF 7. PDU Session Update Request 2 a. Uplink RAN Status Transfer 8 a. Session Modification 2 b. Communication Transfer Source I-UPF (PSA) / h. SMF 8 b. Session Modification 9. Session Modification 2 c. Downlink RAN Status Transfer 10. PDU Update Response 2 d. Session Downlink User Plane Data 2 e. Direct data forwarding 11. Registration Procedure 2 f. Indirect data forwarding 12 c. Session Modification 12 a. Session Release 12 b. UE Context Release Command 2 g. Uplink User Plane Data

120 Inter NG-RAN node N 2 based handover Execution phase (Step 3) UE Source g. NB Target g. NB Source AMF Target I-UPF SMF / v. SMF Source I-UPF (PSA) / h. SMF 1. Handover Command 2. Status Transfer 3. Handover Confirm 4. Handover Notify Handover Confirm 5. Communication Notify • After the UE has successfully synchronized to the target cell • Sends a Handover Confirm message to the Target g. NB 6. PDU Session Release • Handover is by this message considered as successful by the UE • UE can be send Uplink data to Target g. NB and receive Downlink data from Target g. NB 7. PDU Session Update Request UE Source Target Source UPF (PSA) / 8 a. Session Modification. Target 8 b. Session Modification g. NB I-UPF h. SMF 2 d. Downlink User Plane Data 9. Session Modification Direct data. Update forwarding 10. 2 e. PDU Session Response 11. Registration Procedure 2 f. Indirect data forwarding 12 b. UE Context Release Command 12 a. Session Release Session 2 g. 12 c. Uplink User Modification Plane Data

121 Inter NG-RAN node N 2 based handover Execution phase (Step 4) UE Source g. NB Target g. NB Source AMF Target I-UPF SMF / v. SMF Source I-UPF (PSA) / h. SMF 1. Handover Command 2. Status Transfer 3. Handover Confirm 4. Handover Notify 5. Communication Notify Handover Confirm • Handover is by this message considered as successful in Target g. NB 6. PDU Session Release 7. PDU Session Update Request 8 a. Session Modification 8 b. Session Modification 9. Session Modification 10. PDU Session Update Response 11. Registration Procedure 12 b. UE Context Release Command 12 c. Session Modification 12 a. Session Release

122 Inter NG-RAN node N 2 based handover Execution phase (Step 5) UE Source g. NB Target g. NB Source AMF Target I-UPF SMF / v. SMF Source I-UPF (PSA) / h. SMF 1. Handover Command 2. Status Transfer 3. Handover Confirm 4. Handover Notify 5. Communication Notify 6. PDU Session Release 7. PDU Session Update Request The Target AMF notifies to the Source AMF about the A timer in Source AMF is started to supervise N 2 handover notify received from the Target g. NB when resources in Source RAN shall be release 8 a. Session Modification Conditional • If there is an AMF relocation 8 b. Session Modification 9. Session Modification 10. PDU Session Update Response AMF Services └ Namf_Communication_N 2 Info. Notify 11. Registration Procedure 12 b. UE Context Release Command 12 c. Session Modification 12 a. Session Release

123 Inter NG-RAN node N 2 based handover Execution phase (Step 6) UE Source g. NB Target g. NB Source AMF Target I-UPF SMF / v. SMF Source I-UPF (PSA) / h. SMF 1. Handover Command 2. Status Transfer 3. Handover Confirm 4. Handover Notify 5. Communication Notify 6. PDU Session Release 7. PDU Session Update Request Conditional • If the PDU Session(s) is not accepted by the Target AMF 8 a. Session Modification SMF Services └ Nsmf_PDUSession_Release. SMContext Request 8 b. Session Modification 9. Session Modification 10. PDU Session Update Response Input • SUPI 11. Registration Procedure • PDU Session ID • N 2 SM Information 12 c. Session Modification 12 a. Session Release 12 b. UE Context Release Command • Secondary RAT Usage Data • Handover Flag

124 Inter NG-RAN node N 2 based handover Execution phase (Step 7) UE Source g. NB Target g. NB Source AMF Target I-UPF SMF / v. SMF Source I-UPF (PSA) / h. SMF 1. Handover Command 2. Status Transfer 3. Handover Confirm 4. Handover Notify 5. Communication Notify 6. PDU Session Release 7. PDU Session Update Request SMF Services └ Nsmf_PDUSession_Update. SMContext Request 8 a. Session Modification 8 b. Session Modification 9. Session Modification 10. PDU Session Update Response Input • Handover Complete indication for PDU Session ID 11. Registration Procedure • Handover Complete indication is sent per each PDU Session to the corresponding SMF • UE presence in LADN service area 12 c. Session Modification 12 a. Session Release 12 b. UE Context Release Command • If the PDU Session is related to a LADN

125 Inter NG-RAN node N 2 based handover Execution phase (Step 9) UE Source g. NB Target g. NB Source AMF Target I-UPF SMF / v. SMF Source I-UPF (PSA) / h. SMF 1. Handover Command SMF <-> Target I-UPF Modify N 3 tunnel (g. NB <-> UPF) 2. Status Transfer • Downlink 3. Handover Confirm N 4 Session Modification Request 4. Handover Notify • DL AN Tunnel Info of Target g. NB N 4 Session Modification Response 5. Communication Notify Conditional 6. PDU Session Release • If new Target UPF is inserted or an existing intermediate Source UPF is re-allocated 7. PDU Session Update Request 8 a. Session Modification SMF <-> Source I-UPF Modify N 3 tunnel (g. NB <-> UPF) • Downlink N 4 Session Modification Request • DL AN Tunnel Info of Target g. NB N 4 Session Modification Response 9. Session Modification 10. PDU Session Update Response 11. Registration Procedure 12 b. UE Context Release Command Conditional • If UPF is not re-allocated 8 b. Session Modification 12 c. Session Modification 12 a. Session Release

126 Inter NG-RAN node N 2 based handover Execution phase (Step 9) Source g. NB UE Target g. NB Source AMF Target I-UPF SMF / v. SMF Source I-UPF (PSA) / h. SMF <-> UPF(PSA)1. Handover Command Modify N 3 tunnel (g. NB <-> UPF) • Downlink 2. Status Transfer 3. Handover Confirm N 4 Session Modification Request • N 3 AN Tunnel Info of T-RAN 4. Handover Notify • if a new T-UPF is inserted • the DL CN Tunnel Info of T-UPF 5. Communication Notify • Existing intermediate S-UPF is re-allocated N 4 Session Modification Response 6. PDU Session Release • UPF (PSA) sends one or more "end marker" packets for each N 3 tunnel on the 7. PDU Session Update Request old path immediately after switching the path, the source NG-RAN shall forward the "end marker" packets to the target NG-RAN 8 a. Session Modification Conditional • If Target UPF is inserted or an existing intermediate Source UPF is re-allocated UE Source g. NB Target I-UPF 8 b. Session Modification 9. Session Modification 10. PDU Session Update Response Source I-UPF (PSA) / h. SMF 11. Registration Procedure Downlink User Plane Data 12 b. UE Context Release Command Uplink User Plane Data 12 c. Session Modification 12 a. Session Release

127 Inter NG-RAN node N 2 based handover Execution phase (Step 10) UE Source g. NB Target g. NB Source AMF Target I-UPF SMF / v. SMF Source I-UPF (PSA) / h. SMF 1. Handover Command 2. Status Transfer 3. Handover Confirm 4. Handover Notify 5. Communication Notify 6. PDU Session Release 7. PDU Session Update Request 8 a. Session Modification 8 b. Session Modification 9. Session Modification 10. PDU Session Update Response SMF Services └ Nsmf_PDUSession_Update. SMContext Response 11. Registration Procedure Input 12 b. UE Context Release Command • PDU Session ID 12 c. Session Modification 12 a. Session Release

128 Inter NG-RAN node N 2 based handover Execution phase (Step 11) UE Source g. NB Target g. NB Source AMF Target I-UPF SMF / v. SMF Source I-UPF (PSA) / h. SMF 1. Handover Command 2. Status Transfer 3. Handover Confirm 4. Handover Notify 5. Communication Notify 6. PDU Session Release 7. PDU Session Update Request 8 a. Session Modification 8 b. Session Modification 9. Session Modification UE initiates Mobility Registration Update procedure 10. PDU Session Update Response 11. Registration Procedure 12 b. UE Context Release Command 12 c. Session Modification 12 a. Session Release

129 Inter NG-RAN node N 2 based handover Execution phase (Step 12) UE Source g. NB Target g. NB Source AMF Target I-UPF 1. Handover Command SMF / v. SMF Source I-UPF 12 a. SMF <-> Source I-UPF Release Source I-UPF resource Release indirect data forwarding resource 2. Status Transfer 3. Handover Confirm 4. Handover Notify 5. Communication Notify 6. PDU Session Release N 4 Session Release Request • Release Cause N 4 Session Release Response Conditional • If there is a source intermediate UPF 7. PDU Session Update Request 12 c. SMF <-> Target I-UPF Release indirect data forwarding 8 a. Session Modification 8 b. Session Modificationresource 12 b. Source g. NB <-> Source AMF Release Source g. NB resource of UE N 4 Session Release Request 9. Session Modification N 4 Session Release Response UE Context Release Command UE Context Release Complete After the timer in step 5 expires UPF (PSA) / h. SMF 10. PDU Session Update Response 11. Registration Procedure 12 b. UE Context Release Command Conditional • If indirect forwarding applies 12 c. Session Modification 12 a. Session Release

131 Qo. S Flow UPF g. NB UE Network Slice GRB : guaranteed flow bit rate PDU Session Data Radio Bearer N 3 Tunnel Qo. S Flow (Non-GBR Qo. S, QFI = 1) Best effort Qo. S Flow (GBR Qo. S, QFI = 2) Skype Video Data Radio Bearer Qo. S Flow (GBR Qo. S, QFI = 3) DN PDU Session Data Radio Bearer Qo. S Flow (GBR Qo. S, QFI = 1) N 3 Tunnel You. Tube Service Data Flow • IP Flow • Ethernet Flow • Other Flow Voice

The principle for classification and User Plane marking for Qo. S Flows and mapping to AN Resources 132

133 Packet processing flow in the UPF SMF N 4 UPF identifies user plane traffic flow based on information received from the SMF Packet Forwarding Control Protocol (PFCP) Packet Detection Rule (PDR) Forwarding Action Rules (FARs) Qo. S Enforcement Rules (QERs) Usage Reporting Rules (URRs)

134 5 G Qo. S Parameters • • 5 G Qo. S Identifier (5 QI) Allocation and Retention Priority (ARP) Reflective Qo. S Attribute (RQA) Notification control Flow Bit Rates Aggregate Bit Rates Default values Maximum Packet Loss Rate

135 5 G Qo. S characteristics associated with 5 QI Resource Type • GBR (Guaranteed Bit Rate) Delay critical GBR • Packet delayed more than PDB is counted as lost if the data burst is not exceeding the MDBV within the period of PDB and the Qo. S Flow is not exceeding the GFBR Non-GBR Priority Level • Priority in scheduling resources among Qo. S Flows Packet Delay Budget (PDB) • Upper bound for the time that a packet may be delayed between the UE and the UPF that terminates the N 6 interface For GBR, PDB shall be interpreted as a Maximum delay with a confidence level of 98 percent if the Qo. S flow is not exceeding the GFBR Packet Error Rate (PER) • Upper bound for a rate of non-congestion related packet losses Averaging window • • For GBR and Delay-critical GBR resource type only Represents the duration over which the GFBR and MFBR shall be calculated Maximum Data Burst Volume (MDBV) • • For Delay-critical GBR resource type only Denotes the largest amount of data that the 5 G-AN is required to serve within a period of 5 G-AN PDB • • •

Standardized 5 QI to Qo. S characteristics mapping Resource Type - GRB 1 Default Priority Level 20 Packet Delay Budget 100 ms Packet Error Rate 10 -2 Default Maximum Data Burst Volume N/A Default Averaging Window 2000 ms 2 40 150 ms 10 -3 N/A 2000 ms 3 30 50 ms 10 -3 N/A 2000 ms 4 50 300 ms 10 -6 N/A 2000 ms 65 7 75 ms 10 -2 N/A 2000 ms 5 QI Value 66 20 100 ms 10 -2 67 15 100 ms 10 -3 N/A 2000 ms 75 136 Example Services Conversational Voice Conversational Video (Live Streaming) Real Time Gaming, V 2 X messages Electricity distribution – medium voltage, Process automation - monitoring Non-Conversational Video (Buffered Streaming) Mission Critical user plane Push To Talk voice (e. g. , MCPTT) Non-Mission-Critical user plane Push To Talk voice Mission Critical Video user plane

Standardized 5 QI to Qo. S characteristics mapping Resource Type - Non-GRB 5 Default Priority Level 10 Packet Delay Budget 100 ms Packet Error Rate 10 -6 Default Maximum Data Burst Volume N/A Default Averaging Window N/A 6 60 300 ms 10 -6 N/A 7 70 100 ms 10 -3 N/A 8 80 300 ms 10 -6 N/A 9 90 300 ms 10 -6 N/A 69 5 60 ms 10 -6 N/A 70 55 200 ms 10 -6 N/A 79 65 50 ms 10 -2 N/A 80 68 10 ms 10 -6 N/A 5 QI Value 137 Example Services IMS Signalling Video (Buffered Streaming) TCP-based (e. g. , www, e-mail, chat, ftp, p 2 p file sharing, progressive video, etc. ) Voice, Video (Live Streaming) Interactive Gaming Video (Buffered Streaming) TCP-based (e. g. , www, e-mail, chat, ftp, p 2 p file sharing, progressive video, etc. ) Same as 5 QI Value 7 Mission Critical delay sensitive signalling (e. g. , MC-PTT signalling) Mission Critical Data (e. g. example services are the same as 5 QI 6/8/9) V 2 X messages Low Latency e. MBB applications Augmented Reality

Standardized 5 QI to Qo. S characteristics mapping Resource Type - Delay Critical GRB 5 QI Value Default Priority Level Packet Delay Budget Packet Error Rate Default Maximum Data Burst Volume Default Averaging Window 82 19 10 ms 10 -4 255 bytes 2000 ms 83 22 10 ms 10 -4 1354 bytes 2000 ms 84 24 30 ms 10 -5 1354 bytes 2000 ms 85 21 5 ms 10 -5 255 bytes 2000 ms Example Services Discrete Automation (see TS 22. 261 [2]) Intelligent transport systems (see TS 22. 261 [2]) Electricity Distribution- high voltage (see TS 22. 261 [2]) 138

139 Allocation and Retention Priority (ARP) • The Qo. S parameter ARP contains information – Priority level • Deciding whether a new Qo. S Flow may be accepted or needs to be rejected in the case of resource limitations • Used to decide which existing Qo. S Flow to pre-empt during resource limitations • Range : 1 to 15 with 1 as the highest level of priority – Levels 1 -8 should only be assigned to resources for services that are authorized to receive prioritized treatment within an operator domain – Levels 9 -15 may be assigned to resources that are authorized by the home network and thus applicable when a UE is roaming – Pre-emption capability • A service data flow may get resources that were already assigned to another service data flow with a lower priority level – Pre-emption vulnerability • A service data flow may lose the resources assigned to it in order to admit a service data flow with higher priority level

140 Reflective Qo. S Attribute (RQA) • The Reflective Qo. S Attribute (RQA) is an optional parameter which indicates that certain traffic (not necessarily all) carried on this Qo. S Flow is subject to Reflective Qo. S. • Only when the RQA is signalled for a Qo. S Flow, the (R)AN enables the transfer of the RQI for AN resource corresponding to this Qo. S Flow. • Reflective Qo. S – Enables the UE to map UL User Plane traffic to Qo. S Flows without SMF provided Qo. S rules and it applies for IP PDU Session and Ethernet PDU Session – Creating UE derived Qo. S rules in the UE based on the received DL traffic

141 Notification control • Indicates whether notifications are requested from the NGRAN when the GFBR can no longer (or can again) be guaranteed for a Qo. S Flow during the lifetime of the Qo. S Flow • For a GBR Qo. S Flow that enabled notification control – NG-RAN determines that the GFBR can no longer be guaranteed, NGRAN shall send a notification towards SMF and keep the Qo. S Flow • While the NG-RAN is not delivering the requested GFBR for this Qo. S Flow – NG-RAN determines that the GFBR can be guaranteed again for a Qo. S Flow - for which a notification that the GFBR can no longer be guaranteed has been sent), the NG-RAN sends a notification, informing the SMF that the GFBR can be guaranteed again

142 Flow Bit Rates • For GBR Qo. S Flows only • Guaranteed Flow Bit Rate (GFBR) - UL and DL – Denotes the bit rate that is guaranteed to be provided by the network to the Qo. S Flow over the Averaging Time Window • Maximum Flow Bit Rate (MFBR) - UL and DL – Limits the bit rate to the highest bit rate that is expected by the Qo. S Flow • Bit rates above the GFBR value and up to the MFBR value, may be provided with relative priority determined by the Priority Level of the Qo. S Flows

143 Aggregate Bit Rates • For Non-GBR Qo. S Flows only • per Session Aggregate Maximum Bit Rate (Session-AMBR) – Limits the aggregate bit rate that can be expected to be provided across all Non-GBR Qo. S Flows for a specific PDU Session – Each PDU Session of a UE is associated Session-AMBR – Retrieved by the SMF from UDM • SMF may use the subscribed Session-AMBR or modify it based on local policy or use the authorized Session-AMBR received from PCF to get the Session-AMBR • per UE Aggregate Maximum Bit Rate (UE-AMBR) – Limits the aggregate bit rate that can be expected to be provided across all Non-GBR Qo. S Flows of a UE – Each UE is associated UE-AMBR – Retrieved from UDM and provided to the (R)AN by the AMF

144 Default values • For each PDU Session Setup, the SMF retrieves the subscribed default 5 QI and ARP values from the UDM. • The subscribed default 5 QI value shall be a Non-GBR 5 QI from the standardized value range. • The SMF may change the subscribed default 5 QI and ARP values based on local configuration or interaction with the PCF

145 Maximum Packet Loss Rate • Indicates the maximum rate for lost packets of the Qo. S flow that can be tolerated in the uplink and downlink direction • Provided to the Qo. S flow if it is compliant to the GFBR

146 Qo. S Rules and Qo. S Profile N 3 UPF DN N 6 Qo. S Profile A Qo. S Flow may either be 'GBR' or 'Non-GBR' depending on its Qo. S profile GBR Qo. S Flow Non-GBR Qo. S Flow • 5 G Qo. S Identifier (5 QI) • Allocation and Retention Priority (ARP) • Flow Bit Rate • Guaranteed Flow Bit Rate (GFBR) • Maximum Flow Bit Rate (MFBR) • (Optionally) Notification control • (Optionally) Maximum Packet Loss Rate • 5 G Qo. S Identifier (5 QI) • Allocation and Retention Priority (ARP) • (Optionally) Reflective Qo. S Attribute (RQA)

147 Qo. S Rules N 3 UPF DN N 6 Qo. S Rules Contains • QFI of the associated Qo. S Flow • UL Packet Filter Set • precedence value Configuration • Explicitly provided to the UE (PDU Session Establishment/Modification procedure) • Pre-configured in the UE • Implicitly derived by the UE by applying Reflective Qo. S Default Qo. S rule • Required to be sent to the UE for every PDU Session establishment and it is associated with a Qo. S Flow • Default Qo. S rule in IP or Ethernet type PDU Session • The only Qo. S rule of a PDU Session with a “match-all filter” Packet Filter Set that allows all UL packets • Default Qo. S rule in Unstructured type PDU Session • Does not contain a Packet Filter Set • Defines the treatment of all packets in the PDU Session

148 Packet Filter Set • The Packet Filter Set is used in the Qo. S rule and the PDR to identify one or more packet (IP or Ethernet) flow(s) • IP Packet Filter Set (For IP PDU Session Type) – – – – Source/destination IP address or IPv 6 prefix Source / destination port number Protocol ID of the protocol above IP/Next header type Type of Service (TOS) (IPv 4) / Traffic class (IPv 6) and Mask Flow Label (IPv 6) Security parameter index Packet Filter direction • Ethernet Packet Filter Set (For Ethernet PDU Session Type) – – – Source/destination MAC address Ethertype Customer-VLAN tag (C-TAG) and/or Service-VLAN tag (S-TAG) VID fields Customer-VLAN tag (C-TAG) and/or Service-VLAN tag (S-TAG) PCP/DEI fields IP Packet Filter Set, in the case that Ethertype indicates IPv 4/IPv 6 payload Packet Filter direction

149 Qos Flow within PDU session establishment UE g. NB AMF UPF SMF 1. PDU Session Establishment Request Step 1, 3 Number Of Packet Filters • Number of supported packet filters for signaled Qo. S rules 2. SMF Selection Step 6 -8 UE • Qo. S Rule(s) • Qo. S Flow level Qo. S parameters g. NB • QFI(s), Qo. S Profile(s) 3. PDU Session Creation 4. UPF Selection 5. Session Establishment 6. PDU Session Message Transfer Step 5, 11 Setting Packet processing flow in the UPF 7. PDU Session Request 8. Resource Setup 9. PDU Session Response Step 9 -10 List of accepted/rejected QFI(s) SMF release the rejected QFI(s) 10. PDU Session Update Request 11. Session Update

150 Reference • TS 23. 501 System architecture for the 5 G System (5 GS) • TS 23. 502 Procedures for the 5 G System (5 GS) • TS 29. 244 Interface between the Control Plane and the User Plane nodes • TS 38. 300 NR; Overall description; Stage-2 • 3 GPP SA 2_121會議報告