Method and apparatus for selecting a user plane function

Abstract

The present application relates to a method and apparatus for selecting a user plane function. One embodiment of the present disclosure provides a method for selecting a user plane function (UPF), comprising: obtaining, by a session management function (SMF), application information in a protocol data unit (PDU) session during a PDU session establishment procedure or during a domain name system (DNS) query processing; and selecting, by the SMF, the UPF based on the application information.

Description

TECHNICAL FIELD

[0001] This application relates to 3rd Generation Partnership Project (3GPP) 5G New Radio (NR), and in particular to a method and apparatus for selecting a User Plane Function (UPF). BACKGROUND

[0002] During a Protocol Data Unit (PDU) session establishment procedure, a Session Management Function (SMF) selects a UPF for the PDU session. However, the selected UPF can not be the appropriate UPF, and thus reselection of the selected UPF can be needed.

[0003] Therefore, it is desirable to provide a solution for more efficiently selecting a UPF. SUMMARY

[0004] The present disclosure provides some embodiments for selecting a UPF.

[0005] Some embodiments of the present application provide a method for selecting a User Plane Function (UPF), comprising: obtaining, by a Session Management Function (SMF), application information in a Protocol Data Unit (PDU) session during a PDU session establishment procedure or during a Domain Name System (DNS) query processing; and selecting, by the SMF, the UPF based on the application information.

[0006] Other embodiments of the present application provide an apparatus, a device comprising: a non-transitory computer readable medium having stored thereon computer executable instructions; and one or more processors coupled to the non-transitory computer readable medium, wherein the computer executable instructions cause the one or more processors to implement a method for selecting a User Plane Function (UPF), the method comprising: obtaining, by a Session Management Function (SMF), application information in a Protocol Data Unit (PDU) session during a PDU session establishment procedure or during a Domain Name System (DNS) query processing; and selecting, by the SMF, the UPF based on the application information. BRIEF DESCRIPTION OF DRAWINGS

[0007] Figure 1 Information elements contained in a conventional Application Function (AF) request are depicted.

[0008] Figure 2 A flowchart 200 is depicted illustrating that an AF request affects traffic routing for a session identified by a UE address.

[0009] Figure 3 A flowchart 300 is depicted illustrating that an AF request affects traffic routing for a session not identified by a UE address, affecting future PDU sessions.

[0010] Figure 4 Flowchart 400 depicts a procedure illustrating AF request impact on traffic routing for sessions not identified by UE address, thereby impacting ongoing PDU sessions.

[0011] Figure 5 Flowchart 500 depicts a scenario where different applications have different traffic routing requirements due to application deployment.

[0012] Figure 6 Flowchart 600 depicts a procedure illustrating a method for selecting a UPF according to preferred embodiments of the present disclosure.

[0013] Figure 7 Flowchart 700 depicts another procedure illustrating a method for selecting a UPF according to preferred embodiments of the present disclosure.

[0014] Figure 8 Flowchart 800 depicts yet another procedure illustrating a method for selecting a UPF according to preferred embodiments of the present disclosure.

[0015] Figure 9 Flowchart 900 depicts still another procedure illustrating a method for selecting a UPF according to preferred embodiments of the present disclosure.

[0016] Figure 10 Method 1000 illustrates a method for selecting a UPF according to preferred embodiments of the present disclosure. DETAILED DESCRIPTION

[0017] The detailed description of the drawings is intended as a description of the current preferred embodiments of the application and is not intended to represent the only forms in which the present application can be practiced. It is understood that the same or equivalent functions can be accomplished by different embodiments that are intended to be encompassed within the spirit and scope of the application.

[0018] Embodiments provide a method and apparatus for selecting a UPF. To facilitate understanding, embodiments are provided under a specific network architecture and new service scenarios, e.g. 3GPP 5G. It is clear to those skilled in the art that embodiments in the present disclosure can also be applicable to similar technical problems as network architecture and new service scenarios are developed.

[0019] In the present application, several network functions are involved. Specifically, the present application is not intended to limit the names of network functions to apply the described method, and the present application mainly involves the following functions:

[0020] i) SMF: SMF contains various functionalities related to user sessions, such as session establishment, modification and release.

[0021] ii) UPF: The UPF plays a similar role as the serving / packet gateway in the 4G LTE system. The UPF supports features and capabilities that facilitate user plane operations. Examples include: packet routing and forwarding, interworking with data networks, policy enforcement, and data buffering.

[0022] iii) Access and Mobility Management Function (AMF), the main tasks of the AMF include: registration management, connection management, reachability management, mobility management, and various functions related to security and access management and authorization.

[0023] iv) AF: The AF is a logical element of the 3GPP PCC framework that provides session-related information to the PCRF to support PCC rule generation.

[0024] v) Policy Control Function (PCF): The PCF supports a unified policy framework that governs network behavior. When doing so, it provides policy rules to control plane function(s) to enforce the policy rules. To facilitate subscription, information is collected from a unified data management function.

[0025] vi) Network Exposure Function (NEF): The NEF provides a means for securely exposing services and capabilities provided by 3GPP network functions.

[0026] vii) Unified Data Repository (UDR), the UDR is an aggregated repository of user information and can be used to serve several network functions.

[0027] viii) PSA (PDU Session Anchor): The PSA is a UPF that provides access to a Data Network (DN). PSA selection / reselection / relocation is a subset of UPF selection / reselection / relocation.

[0028] It should be noted that the names of the parameters in this application are only for the purpose of explaining the function of the parameters and are not limited to the names themselves. Any parameter that has the function of a parameter as described in this application should be considered the same parameter. For example, an application identifier or a traffic routing requirement. An application identifier is information to identify an application, which can also be called AppID, AppId, or application identity, etc.

[0029] Figure 1 Information elements contained in a regular Application Function (AF) request are depicted. The AF request is sent by the AF to influence SMF routing decisions for PDU session traffic. The AF request can influence UPF (re)selection and allow user traffic to be routed to a local access to a data network identified by a Data Network Access Identifier (DNAI). To allow the AF to interact with the PCF directly or via the NEF, the AF request can contain as Figure 1The following information contained in the AF request: i) Service description; ii) Potential application location; iii) Target UE identifier(s); iv) Spatial validity conditions; v) AF transaction identifier; vi) Service routing requirements; vii) Application relocation possibility; viii) UE IP address preservation indication; ix) Time validity conditions, etc.

[0030] The information contained in the AF request has information to identify the service. For example, the service can be identified in the AF request by: 1) Data Network Name (DNN) and possibly slice information, e.g. Single Network Slice Selection Assistance Information (S-NSSAI) or AF service identifier; and 2) Application identifier or service filtering information, e.g. 5-tuple. When the AF provides an AF service identifier, i.e. an identifier of the service on behalf of which the AF is making the request, the 5G Core maps this identifier into a target DNN and slice information, i.e. S-NSSAI. The AF service identifier can be used to authorize the AF request when the NEF processes the AF request. The application identifier refers to the application handling the UP traffic and is used by the UPF to detect the application's traffic. When the AF request is for influencing SMF routing decisions, the information is used to identify the traffic to be routed. When the AF request is for subscribing to notifications about UP path management events, the information is used to identify the traffic related to the event.

[0031] The information contained in the AF request also has information about the UE(s). This can correspond to: i) Individual UEs identified using GPSI or IP address / prefix or MAC address; ii) Group of UEs identified by an external group identifier when the AF interacts via the NEF or by an internal group identifier when the AF directly interacts with the PCF; or iii) Any UE accessing the combination of DNN, S-NSSAI and DNAI(s).

[0032] When the AF request is for any UE or group of UEs, the AF request can influence multiple PDU Sessions that can be served by multiple SMFs and PCFs.

[0033] When the AF request is for a group of UEs, the AF provides one or several group identifiers in its request. The group identifier provided by the AF is mapped to an internal group identifier. The members of the group have this group identifier in their subscription. The internal group identifier is stored in the Unified Data Management (UDM), retrieved by the SMF from the UDM and passed to the PCF by the SMF at PDU Session establishment. The PCF can then map the AF request to the user subscription and determine whether the AF request for the group of users applies to a PDU Session.

[0034] AF requests can be for individual UE addresses or for PDU sessions not identified by a UE address. When AF requests are for individual UE addresses: such requests are routed to individual PCFs by the AF or by the NEF, using the Binding Support Function (BSF) or by configuration as described in Figure 2 clause 5.5.3.2. Such requests are for ongoing PDU sessions. Whether the AF needs to use the NEF depends on local deployment.

[0035] When AF requests are for PDU sessions not identified by a UE address: for such requests, the AF shall contact the NEF and the NEF stores the AF request information in the UDR. The PCF(s) that have subscribed to AF request information modification receive corresponding notification from the UDR. Such requests can be for ongoing or future PDU sessions as described in Figure 3 and 4 clauses 5.5.3.1 and 5.5.3.2 respectively.

[0036] Figure 2 A flow diagram 200 illustrating the traffic routing for AF requests affecting sessions not identified by a UE address, affecting future PDU sessions is depicted. A similar flow diagram is also described in 3GPP TS 29.513 in clause 5.5.3.2. In Figure 2 clause 5.5.3.2, five different network functions are involved, which are: SMF, PCF, BSF, NEF and AF.

[0037] In step 201A, the AF sends an AF request to the PCF via the NEF. In step 201B, the AF sends an AF request directly to the PCF.

[0038] In steps 202 and 203, upon receiving the AF request, the PCF invokes the Npcf_SMPolicyControl_UpdateNotify service operation by sending an HTTP POST request to the resource URI “{Notification URI} / update” to update the SMF with the corresponding policy and charging control (PCC) rule(s). If the AF subscribes to user plane path change event, the PCF will include the relevant subscription information within the corresponding PCC rule(s).

[0039] In step 204A, corresponding to step 201A, if the SMF observes (several) PDU session related events that the AF has subscribed to, the SMF invokes Nsmf_EventExposure_Notify via the NEF by sending an HTTP POST request. Upon receiving the Nsmf_EventExposure_Notify service operation, the NEF performs information mapping, e.g. AF transaction internal ID to AF transaction ID, Subscription Permanent Identifier (SUPI) to GPSI, etc., and invokes the Nnef_TrafficInfluence_Notify service operation to forward the notification to the AF. These steps are the same as steps 307-310 in Figure 3 .

[0040] In step 204B, corresponding to step 201B, if the SMF observes (several) PDU session related events that the AF has subscribed to, the SMF invokes Nsmf_EventExposure_Notify directly to the AF by sending an HTTP POST request to the resource URI “{notifUri}”, and the AF sends a “204 No Content” response to the SMF.

[0041] Figure 3 A flow diagram 300 illustrating an AF requesting influence on traffic routing for a session not identified by a UE address, thus influencing future PDU sessions, is depicted. A similar flow diagram is also described in 5.5.3.3 in 3GPP TS 29.513. In Figure 3 , five different network functions are involved, which are: SMF, PCF, UDR, NEF, and AF. The detailed procedure is executed as follows:

[0042] In step 301, the AF invokes the Nnef_TrafficInfluence_Create service operation, the Nnef_TrafficInfluence_Update service operation, or the Nnef_TrafficInfluence_Delete service operation to the NEF to create a new AF request, update an existing AF request, or remove an existing AF request, respectively.

[0043] In step 302, upon receiving the AF request, the NEF authorizes it and then maps from the information provided by the AF to the information required by the 5G core network.

[0044] In steps 303 and 304, the UDR sends responses to the NEF. In particular, when receiving the Nnef_Trafficlnfluence_Create request, the NEF invokes the Nudr_DataRepository_Create service operation to store the AF request information in the UDR and sends a "201 Created" response. When receiving the Nnef_Trafficlnfluence_Update service operation, the NEF invokes the Nudr_DataRepository_Update service operation to modify the AF request information in the UDR and sends a "200 OK" or "204 No Content" response accordingly. When receiving the Nnef_Trafficlnfluence_Delete request, the NEF invokes the Nudr_DataRepository_Delete service operation to delete the AF requirement from the UDR and sends a "204 No Content" response.

[0045] In step 305, the NEF sends the HTTP response message to the AF accordingly.

[0046] In step 306, the PCF retrieves the stored AF request in the UDR by invoking the Nudr_DataRepository_Query service operation during the SM Policy Association Setup procedure. The PCF generates the PCC rule(s) based on the AF request and provides it to the SMF. If the AF subscribes to the user plane path change event, the PCF includes the notification URI pointing to the NEF and the notification related ID assigned by the NEF, i.e. the AF transaction internal ID, in the corresponding PCC rule(s). If the AF unsubscribes from the user plane path change event, the PCF removes the related subscription information from the corresponding PCC rule(s).

[0047] In step 307, if the SMF observes the PDU session related event(s) that the AF has subscribed, the SMF invokes the Nsmf_EventExposure_Notify service operation towards the NEF by sending a HTTP POST request to the resource URI "{notifUri}".

[0048] In step 308, when receiving the Nsmf_EventExposure_Notify service operation, the NEF performs information mapping, i.e. maps the AF transaction internal ID with the AF transaction ID, and invokes the Nnef_Trafficlnfluence_Notify service operation by sending a HTTP request to the resource URI "notificationDestination" to forward the notification to the AF.

[0049] In step 309, the AF sends an HTTP "204 No Content" response to the NEF.

[0050] In step 310, the NEF sends an HTTP "204 No Content" response to the PCF.

[0051] Figure 4 Flowchart 400 depicts the procedure for an AF requesting an impact on traffic routing for sessions not identified by a UE address, thus impacting future PDU sessions. A similar flowchart is also described in 5.5.3.3 in 3GPP TS 29.513. In Figure 4 , five different network functions are involved, which are: SMF, PCF, UDR, NEF and AF, and the detailed procedure is executed as follows:

[0052] In step 401, the PCF subscribes to changes in traffic routing requirements in the UDR during the SM policy association procedure. Steps 402-406 are the same as steps 301-305 in Figure 3 .

[0053] In steps 407 and 408, the UDR invokes the Nudr_DataRepository_Notify service operation to the (several) PCF(s) that have subscribed to the AF request modification by sending an HTTP POST request to the resource URI "{notificationUri}", and the PCF sends a "204 No Content" response to the UDR.

[0054] In steps 409 and 410, upon receiving the AF request from the UDR, the PCF determines whether existing PDU sessions can be impacted by the AF request. For each of these PDU sessions, the PCF invokes the Npcf_SMPolicyControl_UpdateNotify service operation to update the SMF with the corresponding PCC rule(s) by sending an HTTP POST request to the resource URI "{Notification URI} / update". If the AF subscribes to user plane path change events, the PCF includes the notification URI pointing to the NEF and the notification related ID, i.e. the AF transaction internal ID, within the corresponding PCC rule(s). If the AF unsubscribes from user plane path change events, the PCF removes the related subscription information from the corresponding PCC rule(s).

[0055] Steps 411-414 are the same as steps 307-310 in Figure 3 .

[0056] Figure 5Scenario 500 is depicted in which different applications have different traffic routing requirements due to application deployment, in accordance with a preferred embodiment of the present disclosure. Note that traffic routing requirements can have different names transmitted over different interfaces or stored in different network functions. Traffic routing requirements can include a routing profile ID and / or N6 traffic routing information corresponding to each DNAI. It should be noted that any parameter referring to the above parameters should be considered as a traffic routing requirement of the present disclosure and the present disclosure is not intended to limit it.

[0057] In Figure 5 which an edge platform is deployed to provide different services, thus different applications have different traffic routing requirements due to different application deployment. Specifically, a user equipment (UE) is connected to a (radio) access network ((R)AN), the (R)AN is connected to different UPFs (UPF PSA1, UPF PSA2, UPF PSA3 and UPF PSA4) via interface N3, the UPF PSA1, UPF PSA2, UPF PSA3 and UPF PSA4 are connected to data networks including central data networks and edge data networks (EDNs), e.g. EDN1, EDN2 and EDN3, respectively, via interface N6. A core network control plane (CN CP) interacts with an EDN configuration server (EDN CS) / edge enablement server (ESS), EDN1, EDN2 and EDN3 for control plane signaling, and a centralized EDN CS / EES or a distributed EES can act as an AF for interacting with the CN CP. EDN1 can be accessed via a data network access identifier (DNAI), i.e. DNAI1, and includes a first edge enablement client (ESS) ESS1, and an edge application server (EAS) 11 is configured on ESS1 for a first application (e.g. App1), and EAS 12 is also configured on ESS1 for a second application (e.g. App2). EDN2 can be accessed via DNAI2 and includes a second ESS (e.g. ESS2), and EAS 21 is configured on ESS2 for a first application (e.g. App1) and EAS 22 for a third application (e.g. App3). EDN3 can be accessed via DNAI3 and includes a third ESS (e.g. ESS3), and EAS 31 is configured on ESS3 for a second application (e.g. App2) and EAS 32 for a third application (e.g. App3). Note that Figure 5 Only an example of edge network, there can be other numbers of UEs, (R)ANs, etc., and the EDNs can include other numbers of EASs, the present disclosure is not intended to limit the structure of edge network.

[0058] Each application configuration traffic routing requirement means different applications can have different deployments, and this information can be sent from the AF. However, when the PCF invokes a service, e.g., Nudr_DataRepository_Query service to retrieve stored AF impact data during a session management (SM) policy association establishment procedure, the retrieved AF impact data can include S-NSSAI and DNN and / or internal group identifier or SUPI. The PCF will retrieve all traffic routing requirements related to S-NSSAI & DNN and / or internal group identifier or SUPI. Therefore, the following cases can have some problems:

[0059] The first case: During a PDU session establishment procedure, the SMF can select one UPF for the PDU session. Although the PCF can get all related traffic routing requirements, the SMF cannot retrieve the traffic routing requirements and cannot decide which one is the best PDU for the PDU session, and even if the SMF can get all traffic routing requirements, it cannot decide which one is the best PDU for the PDU session because the SMF does not know which application is requesting the service. For example, in Figure 5 if PSA2 is selected (PSA2 is connected to EDN1 on which App1 and App2 are provided), App3 is triggered immediately after the PDU session is established, so PSA needs to be relocated or PSA is selected for the second time.

[0060] The second case: The PDU session establishment procedure is triggered by App1. Although the SMF can get all related traffic routing requirements, the SMF does not know which application the UE will use. In Figure 5 PSA1 is not connected to EDN on which App1 is provided (if PSA1 is selected by the SMF), it cannot provide the service required by the UE, so PSA relocation is needed immediately after App1 starts to deliver user data.

[0061] It can be seen that the above two cases cause the SMF to select the UPF again. That is, these problems reduce the efficiency of UPF selection for applications deployed in edge environments. The present disclosure aims to improve the UPF selection of a PDU session for the case where different applications have different traffic routing requirements due to application deployment.

[0062] In particular, the present disclosure aims to solve the following problems:

[0063] i) How does the SMF decide to select which UPF will be efficient for a specific application?

[0064] ii) What information does the SMF need to select the UPF?

[0065] iii) What is the UE / network (NW) behavior to support the selection?

[0066] The present application is intended to provide a method for improving UPF selection of applications deployed in edge environment by: 1) SMF acquiring the applications in a PDU session during PDU session establishment procedure or during DNS query processing; and 2) SMF selecting or reselecting UPF based on the application information.

[0067] Figure 6 A flowchart 600 illustrating a method for selecting a UPF according to a preferred embodiment of the present disclosure is depicted.

[0068] Figure 6 The method in FIG. 1 assumes that: 1) a service provider deploys services into an EDN and different applications have different deployments, 2) an EES / EDN CS sends each DNN and NSSAI / AF service ID and traffic routing requirements of an application to a 3GPP network, and an AF request includes that AF transaction identifier, and 3) an AF request is for future protocol data unit (PDU) sessions of any UE of each application.

[0069] In step 601, an AF request with traffic routing requirements is sent to a core network of each application without a need of individual UE address, such as IP address or MAC address of a UE. Specifically, an AF can send a Nef_TrafficInfluence_Create request (AnyUE, traffic filter (DNN & NSSAI / AF-service-ID / application ID), traffic routing (RouteToLocation1 (DNAI-1, routeInfor1…), …)) to a NEF.

[0070] In step 602, the NEF stores the traffic routing requirements into a UDR. The traffic routing requirements can include an AF transaction internal ID, S-NSSAI and DNN and / or internal group identifier or SUPI. In step 603, a response message is sent out for the AF request. For example, the response can be a Nnef_TrafficInfluence_Create response.

[0071] In step 604, a UE registers into a 5G system. In step 605, the UE initiates a PDU session establishment procedure. Specifically, the UE sends a PDU establishment request message. When the procedure is triggered by initiating one of the applications, application information, such as application identifier (if available), is included. The SMF acquires the application identifier and stores the application information.

[0072] In steps 606 and 607, the SMF retrieves the SM policy using the SM Policy Association Establishment procedure during the PDU Session Establishment procedure. For example, in step 606 the SMF sends a Npcf_SMPolicyControl_Create message to the PCF and receives a Npcf_SMPolicyControl response (SmPolicyDecision(pccRules(flowlnfos, appId, precedence, appReloc, addrPreserind, refTcData(routeToLocs(dnai, routeInfo, routePfid's reference))), which provides the PCC rules in step 607. The Application information obtained in step 605 is used as input for retrieving the SM policy. If the PCF does not have the subscription data for the SUPI and DNN, the PCF invokes the Nudr_DataRepository_Query service to retrieve the stored AF impact data from the UDR. The PCF then makes the SM policy decision for the PDU session and includes the traffic routing requirements of the application information in the SM policy.

[0073] In step 608, the SMF selects a UPF for the PDU session taking into account the traffic routing requirements and the application information. If the application that triggered this PDU session establishment can access an edge data network, the relevant DNAI and PSA will be selected.

[0074] In step 609, the SMF initiates the N4 Session Establishment procedure with the selected UPF. The SMF provides the packet detection, enforcement and reporting rules to be installed on the UPF for this PDU session.

[0075] In step 610, the PDU session is established with the PSA that is suitable for the application that triggered this PDU session establishment.

[0076] Figure 7 Another flowchart 700 illustrating a method for selecting a UPF according to a preferred embodiment of the disclosure is depicted.

[0077] Figure 7 The method in assumes: 1) a PDU session has been established; 2) a service provider has deployed a service, e.g. a new application, into the EDN; 3) the EES / EDN CS sends the traffic routing requirements per DNN & NSSAI / AF service ID and application to the 3GPP network, the AF request includes an AF transaction identifier; 4) the service provider has deployed the service into the EDN and different applications have different deployments; and 5) the AF request is for an ongoing PDU session of the UE per application.

[0078] In steps 701 and 702, the PDU session is established. During the PDU session establishment procedure, the application information (if available) is included and the initial UPF selection can take into account the traffic routing requirements related to the application information, as described in the solution of Figure 6

[0079] In steps 703 to 705, the AF request with traffic routing requirements is sent to the core network per application without the need for individual UE address and traffic routing requirements into the UDR. The Fully Qualified Domain Name (FQDN) information for each application is also included in the AF request. More specifically, in step 703 the AF transmits the Nef_TrafficInfluence_Create request (Any UE, traffic filter (DNN & NSSAI / AF service ID / application ID with FQDN), traffic routing (RouteToLocation 1 (DNAI-1, routeInfo1...),,, ) to the NEF, then in step 704 the NEF stores the information in the UDR and the UDR updates the information to the PCF, and in step 705 the NEF sends the Nef_TrafficInfluence_Create response. That is, the traffic routing requirements can include the AF transaction internal ID, S-NSSAI and DNN and / or internal group identifier or SUPI.

[0080] In step 706, the PCF triggers the SMF to set the application detection rule for the application and / or the forwarding action rule for the DNS query of the application. The FQDN can be included in the Packet Detection Information (PDI) as a separate parameter or as part of the application ID parameter.

[0081] In step 707, if the PCF decides that the PDU session is affected, the SMF is informed of the SM policy updated by the PCF, for example the PCF can invoke the Npcf_SMPolicyControl_UpdateNotify service operation to update the SM policy.

[0082] ​In step 708, when the UE initiates a DNS query and transmits it to the UPF, the UPF detects the application ID based on the FQDN included in the DNS query due to the UPF being configured with the application detection rule applied, in addition, the forwarding action rule for the application's DNS query can also be configured to the UPF, then reports the application detection. If the forwarding action rule for the application's DNS query is set that the application's DNS query should be forwarded to the SMF, the pre-configured DNS query of the application ID / FQDN is forwarded to the SMF for further handling. Alternatively, if the forwarding action rule for the application's DNS query is set that the application's DNS query should be transmitted to the (dedicated) DNS server, the pre-configured DNS query of the application ID / FQDN is forwarded according to the rule.

[0083] In step 709, the SMF handles the DNS query upon receiving it. Based on the UE's location (e.g. UE's cell ID or Tracking Area Identity (TAI)) and the application's routing information, the SMF decides whether the DNAI needs to be changed or whether PSA relocation is needed. The SMF also stores the application ID.

[0084] In steps 710 and 711, if a first uplink packet is sent by the UE, the UPF detects the start of the application and reports the application detection to the SMF based on the application detection rule. Specifically, in step 710, the UE transmits uplink data, and in step 711, the UPF detects the application and sends an application detection report.

[0085] In step 712, the SMF forwards the application detection information to the PCF and the PCF updates the traffic routing requirements to the SMF. Based on the UE's location (e.g. UE's cell ID or TAI) and the application's routing information, the SMF decides whether the DNAI needs to be changed or whether PSA relocation is needed.

[0086] Figure 8 Another flowchart 800 illustrating a method for selecting a UPF according to a preferred embodiment of the present disclosure is depicted.

[0087] In step 801, the UE initiates a PDU session establishment procedure (which is triggered by initiating one of the applications), includes application information, e.g. application identifier, in the PDU session establishment request message if available. The SMF obtains and stores the application information.

[0088] In steps 802 and 803, the SMF retrieves the SM policy using the SM Policy Association Establishment procedure during the PDU session establishment procedure. The application information obtained in step 801 is used as input for retrieving the SM policy. If the PCF does not have the subscription data for the SUPI and DNN, the PCF invokes the Nudr_DataRepository_Query service operation to retrieve the stored AF impact data from the UDR. The PCF then makes the SM policy decision for the PDU session and includes the traffic routing requirements of the application information in the SM policy. In this solution, Figure 1 The traffic routing requirements described in the table in Figure 1 include the routing profile ID and / or N6 traffic routing requirements corresponding to each DNAI, which can be included in the AF request. Furthermore, the traffic routing requirements can also be configured to the PCF or to the SMF.

[0089] In step 804, the SMF selects a PSA for the PDU session taking into account the traffic routing requirements. If the application that triggered this PDU session establishment can access an edge data network, the relevant DNAI and PSA will be selected.

[0090] Figure 9 Another flowchart 900 illustrating a method for selecting a UPF according to a preferred embodiment of the disclosure is depicted.

[0091] In step 901, the SMF sets the application detection rules of the application and the forwarding action rules of the DNS query of the application to the UPF. The FQDN can be included in the PDI as a separate parameter or as part of the application ID parameter. In this solution, Figure 1 The traffic routing requirements described in the table in Figure 1 include the routing profile ID and / or N6 traffic routing requirements corresponding to each DNAI, and can be included in the AF request. Furthermore, the traffic routing requirements can also be configured to the PCF or to the SMF.

[0092] In step 902, the UE initiates a DNS query and transmits it to the UPF. Since the UPF is configured with the application detection rules of the application and the forwarding action rules of the DNS query of the application, the UPF detects the application identifier based on the FQDN included in the DNS query, then forwards the pre-configured DNS query of the application ID / FQDN to the SMF.

[0093] In step 903, the SMF handles the DNS query upon reception. Based on the location of the UE (e.g. cell ID or TAI of the UE) and the routing information of the application (whose traffic routing requirements are available on the SMF or retrieved from the PCF), the SMF decides whether the DNAI needs to be changed or whether a PSA relocation is needed. The SMF also stores the application ID.

[0094] Figure 10 The method 1000 for selecting a UPF is performed is explained according to a preferred embodiment of the present disclosure.

[0095] In step 1001, the SMF obtains application information in a Protocol Data Unit (PDU) session during a PDU session establishment procedure or during a DNS query handling. In step 1002, the SMF selects a UPF based on the application information. For example, in Figure 6 , the SMF obtains an application ID in step 605, and selects a UPF based on a DNAI selected from traffic routing requirements in step 608. The traffic routing requirements can be retrieved based on the application information, e.g. the application ID. Alternatively, the traffic routing requirements can be configured to the PCF or configured to the SMF.

[0096] In one embodiment, the application information is an application identifier. In another embodiment, the application information is included in a PDU session establishment request message during a PDU session establishment procedure. For example, the application ID is included in a PDU session establishment procedure in Figure 6 .

[0097] In a preferred embodiment, the SMF obtains a PCC rule for the PDU session based on the application information. The SMF further selects a UPF based on the PCC rule. In detail, the SMF decides whether a DNAI needs to be changed or whether a PSA relocation is needed based on the location of the UE (e.g. the cell ID or TAI of the UE) and the routing information of the application. The routing information in the SMF can also be retrieved from the PCF based on the application information or configured to the SMF. The routing information in the PCF can be obtained from an AF request sent from the AF directly or indirectly, or configured to the PCF. For example, in Figure 6 , the SMF obtains a PCC rule using a SM policy association establishment procedure during a PDU session establishment procedure in steps 606 and 607, where the application information obtained in step 605 is used as input for retrieving the PCC rule.

[0098] In one preferred embodiment, during the DNS query handling, the UPF detects an application identifier based on a FQDN included in the DNS query according to an application detection rule; and the UPF reports the application identifier to the SMF. For example, in Figure 7 , the UPF detects an application ID based on the FQDN in step 708, and reports the application ID to the SMF.

[0099] In another embodiment, the SMF provides a FQDN corresponding to the application identifier to the application detection rule. The SMF provides a forwarding action rule for the FQDN corresponding to the application identifier; and the UPF forwards a DNS query with the application information and / or the FQDN to the SMF according to the forwarding action rule. For example, inFigure 7 In step 706 in, the SMF sets the application detection rule of the application and the forwarding operation rule of the application's DNS query to the UPF. The application's DNS query forwarding action rule can also be configured to the UPF, the UPF detects the application ID based on the FQDN contained in the DNS query, then reports the application detection. If the application's DNS query forwarding action rule is set to the application's DNS query should be forwarded to the SMF, the pre-configured DNS query of the application ID / FQDN is forwarded to the SMF for further handling. Alternatively, if the forwarding operation rule of the application's DNS query is set, the application's DNS query should be transmitted to the (dedicated) DNS server, then the pre-configured DNS query of the application ID / FQDN is forwarded according to the rule. For example, in Figure 7 In step 708 in, the UE sends the DNS query to the UPF, and the UPF forwards the DNS query to the SMF.

[0100] In another embodiment, the SMF selects the UPF based on the application information and / or the FQDN. For example, in Figure 7 In step 709 in, the SMF selects the UPF based on the application ID and / or the FQDN. In detail, the SMF decides whether the DNAI needs to be changed or whether the PSA relocation is needed based on the UE's location (e.g. the UE's cell ID or TAI) and the routing information of the application. The routing information in the SMF can also be retrieved from the PCF based on the application information or configured to the SMF. The routing information in the PCF can be obtained from the AF request sent from the AF directly or indirectly or configured to the PCF.

[0101] The FQDN is received from the AF and provided to the SMF by the PCF, the FQDN is included in the PDI as a separate parameter or as part of the application information. In addition, the FQDN of the application can also be configured to the SMF or the PCF.

[0102] The SMF of the present application can include a non-transitory computer- readable medium having stored thereon computer-executable instructions, and one or more processors coupled to the non-transitory computer-readable medium. The computer-executable instructions can be programmed to implement a method, for example, the method in Figure 6

[0103] ​The processor can acquire application information in a protocol data unit (PDU) session during a PDU session establishment procedure or during DNS query processing, and further select a UPF based on the application information. The processor can also be implemented on a general or special purpose computer, a programmed microprocessor or microcontroller and peripheral integrated circuit elements, an integrated circuit, a hardware electronic or logic circuit such as a discrete element circuit, a programmable logic device, or the like. In general, processing functions of the disclosure can be implemented with any device including a finite state machine that executes a set of instructions that are arranged in the form of flowcharts. The processor can acquire application information in a protocol data unit (PDU) session during a PDU session establishment procedure or during DNS query processing, and further select a UPF based on the application information. The processor can also be implemented on a general or special purpose computer, a programmed microprocessor or microcontroller and peripheral integrated circuit elements, an integrated circuit, a hardware electronic or logic circuit such as a discrete element circuit, a programmable logic device, or the like. In general, processing functions of the disclosure can be implemented with any device including a finite state machine that executes a set of instructions that are arranged in the form of flowcharts.

[0104] The methods of the disclosure can be implemented on a programmed processor. However, the controller, flowcharts, and modules can also be implemented on a general or special purpose computer, a programmed microprocessor or microcontroller and peripheral integrated circuit elements, an integrated circuit, a hardware electronic or logic circuit such as a discrete element circuit, a programmable logic device, or the like. In general, processing functions of the disclosure can be implemented with any device including a finite state machine that executes a set of instructions that are arranged in the form of flowcharts.

[0105] While the disclosure has been described through its particular embodiments, it is evident that numerous alternatives, modifications and variations of the present disclosure will be apparent to those skilled in the art. For example, various components of the described embodiments can be interchanged, added, or removed in other embodiments. Also, not all of the elements illustrated in each figure are required for operation of the disclosed embodiments. For example, those skilled in the art of the disclosed embodiments will be able to devise their own implementation that, although not explicitly described or shown herein, embody the principles of the disclosure. Thus, the embodiments of the disclosure as set forth herein are intended to be illustrative, not limiting. Various changes can be made without departing from the spirit and scope of the disclosure.

[0106] In the disclosure, relational terms such as“first,”“second,” and the like can be used solely to distinguish one entity or action from another, without necessarily requiring or implying any actual such relationship or order between such entities or actions. The terms“comprises,”“comprising,” or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but can include other elements not expressly listed or inherent to such process, method, article, or apparatus. An element preceded by“a” or“one” does not, without further constraints, preclude the existence of additional identical elements in the process, method, article, or apparatus that includes the element. Furthermore, the term“another” is defined as at least a second or more. The terms“including,”“having,” and the like, as used herein, are defined with the same scope as the term“comprising.”

Claims

1. An apparatus comprising: at least one memory; and at least one processor coupled with the at least one memory and configured to cause the apparatus to: obtain, by a session management function (SMF), application information in a protocol data unit (PDU) session during domain name system (DNS) query handling, wherein the application information includes an application identifier; and select, by the SMF, a user plane function (UPF) based on the application information.

2. The apparatus of claim 1, wherein the at least one processor is further configured to cause the apparatus to: obtain, by the SMF, policy and charging control (PCC) rules for the PDU session based on the application information.

3. The apparatus of claim 2, wherein the at least one processor is further configured to cause the apparatus to: select, by the SMF, the UPF based on the PCC rules.

4. The apparatus of claim 1, wherein during the DNS query handling, the at least one processor is further configured to cause the apparatus to: detect, by a user plane function (UPF), the application identifier based on a fully qualified domain name (FQDN) included in the DNS query according to application detection rules; and report, by the UPF, the application identifier to the SMF.

5. The apparatus of claim 4, wherein the at least one processor is further configured to cause the apparatus to: provide, by the SMF, the application detection rules with the FQDN corresponding to the application identifier.

6. The apparatus of claim 4, wherein the at least one processor is further configured to cause the apparatus to: provide, by the SMF, a forwarding action rule for the FQDN corresponding to the application identifier; and forward, by the UPF, the DNS query with the application information and / or FQDN to the SMF according to the forwarding action rule.

7. The apparatus of claim 4, wherein the at least one processor is further configured to cause the apparatus to: select, by the SMF, the UPF based on the application information and / or FQDN.

8. The apparatus of claim 5, wherein the FQDN is received from an application function (AF) and provided to the SMF by a policy control function (PCF), the FQDN included in packet detection information (PDI) as a separate parameter or as part of the application information.

9. A method for selecting a user plane function (UPF) comprising: obtaining, by a session management function (SMF), application information in a protocol data unit (PDU) session during domain name system (DNS) query handling, wherein the application information includes an application identifier; and selecting, by the SMF, the UPF based on the application information.

10. The method of claim 9, further comprising: obtaining, by the SMF, policy and charging control (PCC) rules for the PDU session based on the application information.

11. The method of claim 10, further comprising: selecting, by the SMF, the UPF based on the PCC rules.

12. The method of claim 9, wherein during the DNS query processing, the method further comprises: detecting, by a user plane function (UPF), the application identifier based on a fully qualified domain name (FQDN) included in the DNS query according to an application detection rule; and reporting, by the UPF, the application identifier to the SMF.

13. The method of claim 12, further comprising: providing, by the SMF, the application detection rule with the FQDN corresponding to the application identifier.

14. The method of claim 12, further comprising: providing, by the SMF, a forwarding action rule for the FQDN corresponding to the application identifier; and forwarding, by the UPF, the DNS query with the application information and / or FQDN to the SMF according to the forwarding action rule.

15. The method of claim 12, further comprising: selecting, by the SMF, the UPF based on the application information and / or FQDN.

16. The method of claim 13, wherein the FQDN is received from an application function (AF) and provided to the SMF by a policy control function (PCF), the FQDN included in a packet detection information (PDI) as a separate parameter or as part of the application information.

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