Method and apparatus for session management

Abstract

Embodiments of the present disclosure provide methods and apparatus for session management. A method includes receiving a request from a user equipment (UE) for establishing another session to a data network identified by a data network identifier. At least one existing session of the UE to the data network has been established. The method also includes checking whether subscription data or policy data for the UE includes a first indication, wherein the first indication indicates that the same session management node is required for multiple sessions to the data network identified by the same data network identifier. The method also includes selecting the same session management node as the at least one existing session of the UE when the subscription data or policy data includes the first indication. The method also includes sending a session establishment request to the selected session management node.

Description

Technical Field

[0001] Non-limiting and exemplary embodiments of the present disclosure relate generally to the field of communication technology, and in particular to methods and apparatus for session management. Background Art

[0002] This section introduces various aspects that may contribute to a better understanding of the present disclosure. Therefore, the statements in this section should be read in this light and should not be understood as an admission about what is or is not in the prior art.

[0003] Core network architectures for fifth generation (5G) systems such as New Radio (NR) have been proposed. Figure 1 is a diagram showing an exemplary 5G system architecture, which is a third generation partnership project (3GPP) TS 23.501 V16.0.2 Figure 4 .2.3-1, the disclosure of which is incorporated herein by reference in its entirety. Figure 1 As shown, the 5G system architecture may include multiple network functions (NFs), such as authentication server function (AUSF), access and mobility management function (AMF), data network (DN) (such as operator service, Internet access or third-party service), network exposure function (NEF), network repository function (NRF), network slice selection function (NSSF), policy control function (PCF), session management function (SMF), unified data management (UDM), user plane function (UPF), application function (AF), user equipment (UE), (radio) access network ((R)AN), etc.

[0004] As described in clause 6.3.2 of 3GPP TS 23.501v16.0.2, if there is an existing protocol data unit (PDU) session and the UE requests to establish another PDU session to the same data network name (DNN) and single network slice selection assistance information (S-NSSAI) and the UE subscription data indicates that interworking with the evolved packet system (EPS) is supported for the DNN and S-NSSAI, the same SMF should be selected. Otherwise, if the UE subscription data does not indicate that interworking with EPS is supported for the DNN and S-NSSAI, a different SMF may be selected. For example, to support SMF load balancing or to support graceful SMF shutdown (e.g., the SMF starts to no longer accept new PDU sessions).

[0005] As described in clause 6.3.7.1 of 3GPP TS 23.501v16.0.2, SMF can use NRF to discover candidate PCF instances (multiple) for PDU sessions. In addition, PCF information can also be configured locally in SMF. Depending on the operator's policy, SMF selects PCF instance based on available PCF instances obtained from NRF or information configured locally in SMF. Summary of the invention

[0006] This Summary is provided in a simplified form to introduce selected concepts that are further described below in the Detailed Description. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter.

[0007] There are some problems with the existing SMF selection and PCF selection for multiple PDU sessions of UEs to the same DNN and S-NSSAI. For example, when the UE establishes multiple PDU sessions to the same DNN and S-NSSAI, if interworking with EPS is not supported, there is no mechanism for the AMF to select the same SMF. In addition, when the AMF selects the same SMF for additional PDU sessions (multiple) of the UE to the same DNN and S-NSSAI, there is no mechanism to ensure that the SMF selects the same PCF. Due to these problems, it may not be possible to monitor the usage of DNN and S-NSSAI for the UE, and the UE may consume more quota than allowed in its policy subscription.

[0008] In order to overcome or alleviate the above-mentioned problems or other problems or provide a useful solution, the embodiments of the present disclosure propose a session management solution, which can ensure that: when the subscription data or policy data associated with the data network identifier for the UE requires the access and mobility management node (such as AMF) to select the same session management node (such as SMF) for multiple sessions of the UE to the same data network identified by, for example, DNN and S-NSSAI, the access and mobility management node (such as AMF) selects the same session management node (such as SMF) for multiple sessions of the UE to the same data network identified by, for example, DNN and S-NSSAI. In addition, the proposed session management solution can ensure that: when the access and mobility management node (such as AMF) selects the same session management node (such as SMF) for multiple sessions of the UE to the same data network identifier (such as DNN and S-NSSAI), the session management node (such as SMF) selects the same policy control node (such as PCF) based on the instruction from the access and mobility management node (such as AMF).

[0009] In a first aspect of the present disclosure, a method at an access and mobility management node is provided. The method includes receiving a request from a user equipment (UE) for establishing another session to a data network identified by a data network identifier. At least one existing session of the UE to the data network has been established. The method also includes checking whether subscription data or policy data for the UE includes a first indication, wherein the first indication indicates that the same session management node is required for multiple sessions to the data network identified by the same data network identifier. The method also includes selecting the same session management node as the at least one existing session of the UE when the subscription data or policy data includes the first indication. The method also includes sending a session establishment request to the selected session management node.

[0010] In one embodiment, the session establishment request may include a second indication to select the same policy control node as at least one existing session.

[0011] In one embodiment, the first indication may also indicate that the same policy control node is required for multiple sessions of the UE to the data network identified by the data network identifier.

[0012] In one embodiment, the data network identifier may be identified by a data network name (DNN) and single network slice selection assistance information (S-NSSAI).

[0013] In one embodiment, the method according to the first aspect of the present disclosure may further include obtaining subscription data from the data management node during a registration process of the UE or when the data management node updates subscription data.

[0014] In one embodiment, the data management node may be a unified data management (UDM) node.

[0015] In one embodiment, the subscription data may be obtained from a Nudm_SDM_Get service operation or from a Nudm_SDM_Notification service operation.

[0016] In one embodiment, the method according to the first aspect of the present disclosure may further include obtaining policy data from the policy control node during a registration procedure of the UE or when the policy control node updates the policy data.

[0017] In one embodiment, policy data may be obtained from an Npcf_AMPolicyControl_Create service operation and / or from an Npcf_AMPolicyControl_Update service operation.

[0018] In one embodiment, the session establishment request may be a protocol data unit (PDU) session establishment request including the second indication.

[0019] In one embodiment, the access and mobility management node may be an access and mobility management function (AMF) node, the session management node may be a session management function (SMF) node, and the policy control node may be a policy control function (PCF) node.

[0020] In a second aspect of the present disclosure, a method at a session management node is provided. The method includes receiving a session establishment request, the session establishment request including a second indication of selecting a policy control node that is the same as at least one existing session of a user equipment (UE). The session establishment request is used to establish another session of the UE to a data network identified by a data network identifier, and at least one existing session of the UE to the data network has been established. The method also includes selecting the same policy control node as at least one existing session of the UE.

[0021] In a third aspect of the present disclosure, a method at a policy control node is provided. The method includes obtaining policy data of a user equipment (UE), the policy data including a first indication indicating that a same session management node is required for multiple sessions of the UE to a data network identified by a data network identifier. The method also includes storing the policy data.

[0022] In one embodiment, the method according to the third aspect of the present disclosure may further include sending the policy data to the access and mobility management node during a registration procedure of the UE or when the policy control node updates the policy data.

[0023] In a fourth aspect of the present disclosure, a method at a data management node is provided. The method includes obtaining subscription data of a user equipment (UE), the subscription data including a first indication indicating that the same session management node is required for multiple sessions of the UE to a data network identified by a data network identifier. The method also includes storing the subscription data.

[0024] In one embodiment, the method according to the fourth aspect of the present disclosure may further include sending the subscription data to the access and mobility management node during the registration process of the UE or when the data management node updates the subscription data.

[0025] In a fifth aspect of the present disclosure, a device at an access and mobility management node is provided. The device includes a processor; and a memory coupled to the processor, the memory storing instructions executable by the processor, whereby the device is operable to receive a request from a user equipment (UE) to establish another session to a data network identified by a data network identifier. At least one existing session of the UE to the data network has been established. The device further operates to check whether subscription data or policy data for the UE includes a first indication, the first indication indicating that the same session management node is required for multiple sessions to the data network identified by the same data network identifier. The device further operates to select the same session management node as at least one existing session for the UE when the subscription data or policy data includes the first indication. The device further operates to send a session establishment request to the selected session management node.

[0026] In a sixth aspect of the present disclosure, a device at a session management node is provided. The device includes a processor; and a memory coupled to the processor, the memory storing instructions executable by the processor, whereby the device is operable to receive a session establishment request, the session establishment request including a second indication of selecting the same policy control node as at least one existing session of a user equipment (UE), wherein the session establishment request is used to establish another session of the UE to a data network identified by a data network identifier, and at least one existing session of the UE to the data network has been established. The device further operates to select the same policy control node as at least one existing session of the UE.

[0027] In a seventh aspect of the present disclosure, a device at a policy control node is provided. The device includes a processor; and a memory coupled to the processor, the memory storing instructions executable by the processor, whereby the device is operable to obtain policy data for a user equipment (UE), the policy data including a first indication indicating that the same session management node is required for multiple sessions of the UE to a data network identified by a data network identifier. The device further operates to store the policy data.

[0028] In an eighth aspect of the present disclosure, a device at a data management node is provided. The device includes a processor; and a memory coupled to the processor, the memory storing instructions executable by the processor, whereby the device further operates to obtain subscription data of a user equipment (UE), the subscription data including a first indication indicating that the same session management node is required for multiple sessions of the UE to a data network identified by a data network identifier. The device further operates to store the subscription data.

[0029] In a ninth aspect of the present disclosure, a computer program product comprising instructions is provided. When the instructions are executed on at least one processor, the instructions cause the at least one processor to perform the method according to the first aspect of the present disclosure.

[0030] In a tenth aspect of the present disclosure, a computer program product comprising instructions is provided. When the instructions are executed on at least one processor, the instructions cause the at least one processor to perform the method according to the second aspect of the present disclosure.

[0031] In an eleventh aspect of the present disclosure, a computer program product comprising instructions is provided. When the instructions are executed on at least one processor, the instructions cause the at least one processor to perform the method according to the third aspect of the present disclosure.

[0032] In a twelfth aspect of the present disclosure, a computer program product comprising instructions is provided. When the instructions are executed on at least one processor, the instructions cause the at least one processor to perform the method according to the fourth aspect of the present disclosure.

[0033] In a thirteenth aspect of the present disclosure, a computer-readable storage medium storing instructions is provided, wherein when the instructions are executed by at least one processor, the at least one processor performs the method according to the first aspect of the present disclosure.

[0034] In a fourteenth aspect of the present disclosure, a computer-readable storage medium storing instructions is provided, wherein when the instructions are executed by at least one processor, the at least one processor causes the at least one processor to perform the method according to the second aspect of the present disclosure.

[0035] In a fifteenth aspect of the present disclosure, a computer-readable storage medium storing instructions is provided, wherein the instructions, when executed by at least one processor, cause the at least one processor to perform a method according to the third aspect of the present disclosure.

[0036] In a sixteenth aspect of the present disclosure, a computer-readable storage medium storing instructions is provided, wherein the instructions, when executed by at least one processor, cause the at least one processor to perform a method according to the fourth aspect of the present disclosure.

[0037] Many advantages can be achieved by applying the proposed solution according to the embodiments of the present disclosure. For example, the proposed solution can ensure that: the same session management node (e.g., SMF) is selected for multiple sessions (e.g., PDU sessions) of the UE to the same data network identified by the data network identifier (e.g., DNN and S-NSSAI), and then the same policy control node (e.g., PCF) is selected. The proposed solution can facilitate the monitoring of the usage of the data network identified by the data network identifier such as DNN and S-NSSAI for the UE, and ensure that the UE does not consume more than the quota allowed in its policy subscription. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] The above and other aspects, features and benefits of various embodiments of the present disclosure will become more apparent from the following detailed description with reference to the accompanying drawings by way of example, wherein like reference numerals or letters are used to designate similar or equivalent elements. The illustrated drawings are not necessarily drawn to scale in order to facilitate a better understanding of the embodiments of the present disclosure, wherein:

[0039] Figure 1 is a diagram illustrating an exemplary 5G system architecture according to an embodiment of the present disclosure;

[0040] Figure 2 A flowchart of a method according to an embodiment of the present disclosure is shown;

[0041] Figure 3 A flowchart of a method according to another embodiment of the present disclosure is shown;

[0042] Figure 4 A flowchart of a method according to another embodiment of the present disclosure is shown;

[0043] Figure 5 A flowchart of a method according to another embodiment of the present disclosure is shown;

[0044] Figure 6 A flowchart of a method according to another embodiment of the present disclosure is shown;

[0045] Figure 7 A flowchart of a method according to another embodiment of the present disclosure is shown;

[0046] Figure 8 A flowchart of a method according to another embodiment of the present disclosure is shown;

[0047] Fig. 9 A flowchart of a method according to another embodiment of the present disclosure is shown;

[0048] Fig.10 A flowchart of a method according to another embodiment of the present disclosure is shown;

[0049] Fig.11 A flowchart showing a method according to another embodiment of the present disclosure; and

[0050] Fig.12a -d illustrates a simplified block diagram of an apparatus according to an embodiment of the present disclosure. DETAILED DESCRIPTION

[0051] Embodiments of the present disclosure are described in detail with reference to the accompanying drawings. It should be understood that these embodiments are discussed only for the purpose of enabling those skilled in the art to better understand and thus realize the present disclosure, rather than suggesting any limitation on the scope of the present disclosure. References to features, advantages or similar language throughout the specification do not mean that all features and advantages that can be implemented with the present disclosure should be in or in any single embodiment of the present disclosure. On the contrary, the language referring to features and advantages should be understood to mean that specific features, advantages or characteristics described in conjunction with the embodiments are included in at least one embodiment of the present disclosure. In addition, in one or more embodiments, the features, advantages and characteristics described in the present disclosure may be combined in any suitable manner. Those skilled in the relevant art will recognize that the present disclosure may be practiced without one or more of the specific features or advantages of a particular embodiment. In other cases, additional features and advantages may be recognized in certain embodiments, and the additional features and advantages may not exist in all embodiments of the present disclosure.

[0052] As used herein, the term "network" refers to a network that complies with any suitable communication standard, such as new radio (NR), or a next generation communication standard. In the following description, the terms "network" and "system" can be used interchangeably. In addition, the communication between two devices in the network can be carried out according to any suitable communication protocol, including but not limited to communication protocols defined by some standardization organizations (such as 3GPP, International Telecommunication Union (ITU), Institute of Electrical and Electronics Engineers (IEEE), and Internet Engineering Task Force (IETF), etc.). For example, the communication protocol defined by 3GPP may include a 5G communication protocol, and / or any other protocol currently known or to be developed in the future.

[0053] The term "network equipment" refers to a network equipment in a communication network, through which a terminal device accesses the network and receives services from the network. For example, in a wireless communication network such as a 3GPP type cellular network, the network equipment may include access network equipment and core network equipment. For example, the access network equipment may include a base station (BS), an integrated access backhaul (IAB) node, an access point (AP), a multi-cell / multiple access coordination entity (MCE), etc. The BS may be, for example, a Node B (NodeB or NB), an evolved NodeB (eNodeB or eNB), a next generation NodeB (gNodeB or gNB), a remote radio unit (RRU), a radio head (RH), a remote radio head (RRH), a repeater, a low-power node (such as a femto base station, a pico base station), etc. The core network equipment may include a plurality of network devices that may provide a variety of services to customers interconnected through the access network equipment. Each access network device may be connected to the core network device via a wired or wireless connection.

[0054] The term "network function (NF)" refers to any suitable function that can be implemented in a network device of a wireless / wired communication network. For example, in a 5G network, the network functions may include AUSF, AMF, DN, NEF, NRF, NSSF, PCF, SMF, UDM, UPF, AF, UE, (R)AN, 5G Equipment Identity Register (5G-EIR), Security Edge Protection Proxy (SEPP), Network Data Analysis Function (NWDAF), Unified Data Repository (UDR), Unstructured Data Repository Function (UDSF), etc.

[0055] The term "terminal device" refers to any terminal device that can access a wireless communication network and receive services from the wireless communication network. As an example and not a limitation, in a wireless communication network, a terminal device may refer to a mobile terminal, a user equipment (UE), a terminal device, or other suitable equipment. The terminal device may be, for example, a subscriber station (SS), a portable subscriber station, a mobile station (MS), or an access terminal (AT). The terminal device may include, but is not limited to, a portable computer, an image capture device such as a digital camera, a game terminal device, a music storage and playback device, a mobile phone, a cellular phone, a smart phone, a voice over IP (VoIP) phone, a wireless local loop phone, a tablet computer, a wearable device, a personal digital assistant (PDA), a portable computer, a desktop computer, a wearable device, a vehicle-mounted wireless device, a wireless endpoint, a mobile station, a laptop embedded device (LEE), a laptop mounted device (LME), a USB dongle, a smart device, a wireless customer premises equipment (CPE), etc. In the following description, the terms "terminal device", "terminal", "user equipment" and "UE" may be used interchangeably. As an example, a UE may represent a terminal device configured to communicate in accordance with one or more communication standards published by 3GPP (such as 3GPP's LTE standard or NR standard). As used herein, a "user equipment" or "UE" may not necessarily have a "user" in terms of a human user who owns and / or operates the associated device. In some embodiments, a terminal device may be configured to send and / or receive information without direct human interaction. For example, when triggered by an internal or external event, or in response to a request from a wireless communication network, a UE may be designed to send information to the network on a predetermined schedule. Alternatively, a UE may represent a device that is intended to be sold to or operated by a human user but may not initially be associated with a specific human user.

[0056] As another example, in an Internet of Things (IOT) scenario, a terminal device may represent a machine or other device that performs monitoring and / or measurement and sends the results of such monitoring and / or measurement to another terminal device and / or network device. In this case, the UE may be a machine-to-machine (M2M) device, which may be referred to as a machine type communication (MTC) device in the 3GPP context. As a specific example, the terminal device may be a terminal device that implements the 3GPP Narrowband Internet of Things (NB-IoT) standard. Specific examples of such machines or devices are sensors, metering devices (e.g., power meters), industrial machinery, or household or personal appliances (e.g., refrigerators, televisions), personal wearable devices (e.g., watches), etc. In other cases, a UE may represent a vehicle or other device that is capable of monitoring and / or reporting its operating status or other functions associated with its operation.

[0057] References in the specification to "one embodiment," "an embodiment," "an example embodiment," etc. indicate that the described embodiment may include a particular feature, structure, or characteristic, but not every embodiment necessarily includes the particular feature, structure, or characteristic. Moreover, such phrases do not necessarily refer to the same embodiment. In addition, when a particular feature, structure, or characteristic is described in conjunction with an embodiment, whether or not explicitly described, it is considered to be within the knowledge of those skilled in the art to affect such feature, structure, or characteristic in conjunction with other embodiments.

[0058] It should be understood that although the terms "first" and "second" etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, without departing from the scope of the exemplary embodiments, the first element may be referred to as the second element, and similarly, the second element may be referred to as the first element. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed terms.

[0059] The terms used herein are for the purpose of describing specific embodiments only, and are not intended to limit the exemplary embodiments. As used herein, the singular forms "a", "an", and "the" are also intended to include the plural forms unless the context clearly indicates otherwise. It will be further understood that when used herein, the terms "include", "comprising", "having", "containing", "covering", and / or "having" specify the presence of stated features, elements, and / or components, etc., but do not exclude the presence or addition of one or more other features, elements, components, and / or combinations thereof.

[0060] As used herein, the phrase "at least one of A and B" should be understood to mean "only A, only B, or both A and B." The phrase "A and / or B" should be understood to mean "only A, only B, or both A and B."

[0061] In the following description and claims, unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs.

[0062] Although the subject matter described herein may be implemented in any suitable type of system using any suitable components, the embodiments disclosed herein are directed to systems that conform to Figure 1 The exemplary system architecture shown is described. Figure 1 The diagram in may represent a high-level architecture in a next generation network such as 5G. For simplicity, Figure 1The system architecture of FIG. 1 depicts only some exemplary elements, such as AUSF, AMF, DN, NEF, NRF, NSSF, PCF, SMF, UDM, UPF, AF, UE, (R)AN. In practice, the communication system may also include any additional elements suitable for supporting communication between terminal devices or between a wireless device and another communication device (e.g., a landline phone, a service provider, or any other network node or terminal device). The communication system may provide communication and various types of services to one or more terminal devices to facilitate terminal devices to access and / or use services provided by or via the communication system.

[0063] like Figure 1 As further shown, the exemplary system architecture also includes service-based interfaces such as Nnrf, Nnef, Nausf, Nudm, Npcf, Namf, and Nsmf, which are exposed by NFs such as NRF, NEF, AUSF, UDM, PCF, AMF, and SMF. In addition, Figure 1 Some reference points, such as N1, N2, N3, N4, N6 and N9, are also shown, which can support the interaction between NF services in the NF. For example, these reference points can be implemented through corresponding NF service-based interfaces and by specifying some NF service consumers and providers and their interactions in order to perform specific system processes.

[0064] Figure 1 The various NFs shown may be responsible for functions such as session management, mobility management, authentication, and security. AUSF, AMF, DN, NEF, NRF, NSSF, PCF, SMF, UDM, UPF, AF, UE, (R) AN may include functions defined in, for example, 3GPP TS 23.501 V16.0.2.

[0065] As used herein, the term "access and mobility management node" may implement access and mobility functions and other suitable functions. The term "session management node" may implement session management functions and other suitable functions. The term "policy control node" may implement policy functions and other suitable functions. Please note that the terms "access and mobility management node", "session management node", "policy control node", etc. used herein are only used to facilitate the description of nodes, devices or networks, etc. and the distinction between nodes, devices or networks, etc. As technology develops, other terms with similar / same meanings may also be used.

[0066] Figure 2 A flowchart of a method 200 according to an embodiment of the present disclosure is shown. The method 200 may be performed by an access and mobility management node (eg, Figure 1The method 200 may be performed by a device implemented in or at the AMF shown in the figure or by a device communicatively coupled to the access and mobility management node. Therefore, the access and mobility management node may provide components for completing various parts of the method 200 and components for completing other processes in combination with other components.

[0067] At box 202, the access and mobility management node receives a request from the UE to establish another session to the data network identified by the data network identifier. At least one existing session of the UE to the data network has been established. For example, depending on the specified network, the data network identifier can be identified in any suitable manner. For example, in the fifth generation system (5GS), the data network identifier can be identified by a data network name (DNN) and a single network slice selection auxiliary information (S-NSSAI). DNN and S-NSSAI may have similar meanings as described in 3GPP TS 23.501V16.0.2. For example, depending on the specified network, the session of the UE to the data network may be any suitable session. For example, in 5GS, the session may be a PDU session. In other communication networks, the session may have similar or different names. In addition, the session may be associated with a specified access technology (e.g., 3GPP access or non-3GPP access). Typically, the establishment of a first session to a UE of a data network may be similar to an existing session establishment as described, for example, in clause 4.3.2 of 3GPP TS 23.502 V16.0.2 (the disclosure of which is incorporated herein by reference in its entirety). The establishment of a second, third, etc. session to a UE of a data network may use the method of an embodiment of the present disclosure.

[0068] In block 204, the access and mobility management node checks whether the subscription data or policy data associated with the data network identifier for the UE includes a first indication that the same session management node and the same policy control node are required for multiple sessions to the data network. The policy data may include policy information associated with the UE. The subscription data may include subscription information associated with the UE. The access and mobility management node may obtain the subscription data or policy data associated with the data network identifier for the UE in a variety of ways. For example, the access and mobility management node (such as AMF) may obtain the subscription data from a data management node such as UDM during the registration process of the UE or when the data management node (such as UDM) updates the subscription data. The access and mobility management node (such as AMF) may obtain the policy data from the policy control node during the registration process of the UE or when the policy control node updates the policy data. The first indication may take any suitable form, such as a bit. For example, a bit "1" may indicate that the same session management node and the same policy control node are required for multiple sessions to the data network, while a bit "0" may indicate that the same session management node and the same policy control node are not required for multiple sessions to the data network. Typically, when the subscription data or policy data is created or updated, the first indication may be created or updated accordingly. Typically, during establishment of a first session of the UE to the data network, the access and mobility management node may obtain the subscription data or policy data.

[0069] In one embodiment, at block 204, the access and mobility management node may check whether subscription data or policy data of the UE includes a first indication that the same session management node is required for multiple sessions to a data network identified by the same data network identification.

[0070] In one embodiment, the first indication further indicates that the same policy control node is required for multiple sessions of the UE to the data network identified by the data network identifier.

[0071] At block 206, when the subscription data or the policy data includes the first indication, the access and mobility management node selects the same session management node as at least one existing session for the UE. For example, when at least one existing session is managed by session management node "A", the access and mobility management node selects the same session management node "A" to serve another session of the UE to the data network.

[0072] In box 208, the access and mobility management node sends a session establishment request to the same session management node as at least one existing session, and the session establishment request includes a second indication of selecting the same policy control node as at least one existing session. For example, depending on the specified network, the session establishment request can be any suitable session establishment request. In 5GS, the session establishment request can be a PDU session establishment request including the second indication. The PDU session establishment request can be similar to the PDU session establishment request described in clause 4.3.2 of 3GPP TS 23.502V16.0.2, except that it can further include a second indication. The second indication can take any suitable form, such as a bit. For example, a bit "1" can indicate to the same session management node as at least one existing session that the same policy control node as at least one existing session is selected, and a bit "0" can indicate to the same session management node as at least one existing session that the same policy control node as at least one existing session does not need to be selected.

[0073] In one embodiment, at block 208, the access and mobility management node sends a session establishment request to the selected session management node.

[0074] In one embodiment, the session establishment request includes a second indication to select the same policy control node as at least one existing session.

[0075] Figure 3 A flowchart of a method 300 according to another embodiment of the present disclosure is shown. The method 300 may be performed by an access and mobility management node (eg, Figure 1 The method 300 may be performed by a device implemented in or at the AMF shown in the figure, or by a device communicatively coupled to the access and mobility management node. Therefore, the access and mobility management node may provide components for completing various parts of the method 300 and components for completing other processes in combination with other components. For some parts that have been described in the above embodiments, they will not be repeated here for the sake of brevity.

[0076] At box 302, the access and mobility management node obtains subscription data from the data management node during the registration process of the UE or when the data management node updates the subscription data. The data management node can be any suitable data management node that can store or access subscription data. For example, in 5GS, the data management node can be a unified data management (UDM) node. In one embodiment, the subscription data can be obtained by the access and mobility management node (e.g., AMF) from the Nudm_SDM_Get service operation or from the Nudm_SDM_Notification service operation. The Nudm_SDM_Get service operation can be similar to the corresponding service operation described in clause 5.2.3.3.2 of 3GPP TS 23.502 V16.0.2. The Nudm_SDM_Notification service operation can be similar to the corresponding service operation described in section 5.2.3.3.3 of 3GPP TS 23.502 V16.0.2. In this embodiment, the subscription data may include a first indication that multiple sessions of the UE to the data network require the same session management node and the same policy control node.

[0077] At block 304 , the access and mobility management node receives a request from the UE to establish another session to the data network identified by the data network identification, wherein at least one existing session of the UE to the data network is already established. Block 304 is similar to block 202 .

[0078] At block 306 , the access and mobility management node checks whether the subscription data associated with the data network identity for the UE includes a first indication that the same session management node and the same policy control node are required for multiple sessions to the data network. Block 306 is similar to block 204 .

[0079] At block 308 , when the subscription data includes the first indication, the access and mobility management node selects the same session management node as the at least one existing session. Block 308 is similar to block 206 .

[0080] At block 310 , the access and mobility management node sends a session establishment request to the same session management node as the at least one existing session, the session establishment request including a second indication to select the same policy control node as the at least one existing session. Block 310 is similar to block 208 .

[0081] Figure 4 A flowchart of a method 400 according to another embodiment of the present disclosure is shown. The method 400 may be performed by an access and mobility management node (eg, Figure 1The method 400 is performed by a device implemented in or at the AMF shown in the figure, or by a device communicatively coupled to the access and mobility management node. Therefore, the access and mobility management node can provide components for completing various parts of the method 400 and components for completing other processes in combination with other components. For some parts that have been described in the above embodiments, they are not repeated here for the sake of brevity.

[0082] At box 402, the access and mobility management node obtains policy data from the policy control node during the registration process of the UE or when the policy control node updates the policy data. The policy control node can be any suitable policy control node that can store or access policy data. For example, in 5GS, the policy control node can be a PCF node. In one embodiment, the policy data can be obtained by the access and mobility management node (e.g., AMF) from the Npcf_AMPolicyControl_Create service operation and / or the Npcf_AMPolicyControl_Update service operation. The Npcf_AMPolicyControl_Create service operation can be similar to the corresponding service operation described in Clause 4.16.1.2 of 3GPP TS 23.502 V16.0.2. The Npcf_AMPolicyControl_Update service operation can be similar to the corresponding service operation described in Clause 4.16.2 of 3GPP TS 23.502 V16.0.2. In this embodiment, the policy data may include a first indication that the same session management node and the same policy control node are required for multiple sessions to the data network.

[0083] At block 404 , the access and mobility management node receives from the UE a request to establish another session to the data network identified by the data network identification, wherein at least one existing session of the UE to the data network is already established. Block 404 is similar to block 202 .

[0084] At block 406 , the access and mobility management node checks whether the policy data associated with the data network identity for the UE includes a first indication that the same session management node and the same policy control node are required for multiple sessions to the data network. Block 406 is similar to block 204 .

[0085] At block 408 , when the policy data includes the first indication, the access and mobility management node selects the same session management node as the at least one existing session. Block 408 is similar to block 206 .

[0086] At block 410 , the access and mobility management node sends a session establishment request to the same session management node as the at least one existing session, the session establishment request including a second indication to select the same policy control node as the at least one existing session. Block 410 is similar to block 208 .

[0087] In various embodiments, the access and mobility management node may obtain subscription data and policy data. The access and mobility management node may select the same session management node as at least one existing session only if one of the subscription data or policy data associated with the data network identity for the UE includes the first indication.

[0088] Figure 5 A flowchart of a method 500 according to another embodiment of the present disclosure is shown. The method 500 may be performed by, for example, Figure 1 The method 500 is performed by a device implemented in or at a session management node of the SMF shown in the figure or by a device communicatively coupled to the session management node. Therefore, the session management node can provide components for completing various parts of the method 500 and components for completing other processes in combination with other components. For some parts that have been described in the above embodiments, they are not repeated here for the sake of brevity.

[0089] At block 502, a session management node receives a session establishment request, the session establishment request including a second indication to select a policy control node that is the same as at least one existing session of a user equipment (UE). The session establishment request may be used to establish another session of the UE to a data network identified by a data network identifier, where at least one existing session of the UE to the data network has been established. For example, the access and mobility management node may be configured to select a policy control node that is the same as at least one existing session of the user equipment (UE). Figure 2-4 The session establishment request including a second indication of selecting the same policy control node as at least one existing session of the UE is sent to the session management node at blocks 208, 310 and 410 of the UE, and the session management node may then receive the session establishment request.

[0090] In block 504, the session management node selects a policy control node that is the same as at least one existing session of the UE.

[0091] Figure 6 A flowchart of a method 600 according to another embodiment of the present disclosure is shown. The method 600 may be performed by, for example, Figure 1 The method 600 is performed by a device implemented in or at a policy control node of the PCF shown in the figure or by a device communicatively coupled to the policy control node. Therefore, the policy control node can provide components for completing various parts of the method 600 and components for completing other processes in combination with other components. For some parts that have been described in the above embodiments, they will not be repeated here for the sake of brevity.

[0092] At block 602, the policy control node obtains policy data for the UE, the policy data for the UE including a first indication that the same session management node and the same policy control node are required for multiple sessions of the UE to a data network identified by a data network identifier. The policy control node may obtain the policy data for the UE in a variety of ways. For example, the policy data for the UE may be entered or updated into the policy control node. The policy control node may obtain the policy data for the UE from another network device, such as a UDR, for example, by retrieving the policy data for the UE from the other network device or receiving a notification from the other network device, for example, when the policy data for the UE has changed.

[0093] In one embodiment, at block 602, a policy control node obtains policy data for a user equipment (UE), the policy data comprising a first indication that the same session management node is required for multiple sessions of the UE to a data network identified by a data network identifier.

[0094] In one embodiment, the first indication further indicates that the same policy control node is required for multiple sessions of the UE to the data network identified by the data network identifier.

[0095] At block 604, the policy control node stores the policy data, for example in its local memory.

[0096] Figure 7 A flowchart of a method 700 according to another embodiment of the present disclosure is shown. The method 700 may be performed by, for example, Figure 1 The method 700 may be performed by a device implemented in or at a policy control node such as the PCF shown in the figure or by a device communicatively coupled to the policy control node. Therefore, the policy control node may provide components for completing various parts of the method 700 and components for completing other processes in combination with other components. For some parts that have been described in the above embodiments, they will not be repeated here for the sake of brevity. Blocks 702 and 704 are similar to Figure 6 Frames 602 and 604.

[0097] At block 706, the policy control node sends the policy data to an access and mobility management node such as the AMF during the registration process of the UE or when the policy control node updates the policy data. The policy data may be sent in any suitable message (e.g., an existing message or a new message). For example, in 5GS, the policy data may be sent in an Npcf_AMPolicyControl_Create service operation and / or an Npcf_AMPolicyControl_Update service operation.

[0098] Figure 8A flowchart of a method 800 according to another embodiment of the present disclosure is shown. The method 800 may be performed by, for example, Figure 1 The method 800 is performed by a device implemented in or at a data management node of the UDM shown in the figure or by a device communicatively coupled to the data management node. Therefore, the data management node can provide components for completing various parts of the method 800 and components for completing other processes in combination with other components. For some parts that have been described in the above embodiments, they are not repeated here for the sake of brevity.

[0099] At block 802, the data management node obtains subscription data for the UE, the subscription data comprising a first indication that the same session management node and the same policy control node are required for multiple sessions of the UE to a data network identified by a data network identifier. The data management node may obtain the subscription data of the UE in a variety of ways. For example, the subscription data of the UE may be entered or updated into the data management node. The data management node may obtain the subscription data of the UE from another network device, such as a UDR, for example, by retrieving the subscription data of the UE from the other network device or receiving a notification from the other network device, for example, when the subscription data of the UE has changed.

[0100] In one embodiment, at block 802, a data management node obtains subscription data of a user equipment (UE), the subscription data comprising a first indication indicating that the same session management node is required for multiple sessions of the UE to a data network identified by a data network identifier.

[0101] In one embodiment, the first indication further indicates that the same policy control node is required for multiple sessions of the UE to the data network identified by the data network identifier.

[0102] At block 804, the data management node stores the subscription data, for example, in its local memory.

[0103] Fig. 9 A flowchart of a method 900 according to another embodiment of the present disclosure is shown. The method 900 may be performed by, for example, Figure 1 The method 900 may be performed by a device implemented in or at a data management node of the UDM shown in the figure or by a device communicatively coupled to the data management node. Therefore, the data management node may provide components for completing various parts of the method 900 and components for completing other processes in combination with other components. For some parts that have been described in the above embodiments, they will not be repeated here for the sake of brevity. Blocks 902 and 904 are similar to Figure 8 Frames 802 and 804.

[0104] In block 906, the data management node sends the subscription data to the access and mobility management node during the registration process of the UE or when the data management node updates the subscription data. The subscription data may be sent in any suitable message (e.g., an existing message or a new message). For example, in 5GS, the subscription data may be sent in a Nudm_SDM_Get service operation and / or a Nudm_SDM_Notification service operation.

[0105] In various embodiments, the access and mobility management node may be an AMF node, the session management node may be an SMF node, and the policy control node may be a PCF node.

[0106] Fig.10 FIG. 1 is a flow chart of a method according to another embodiment of the present disclosure. In this embodiment, the method can be implemented in 5GS. Fig.10 The message shown in is similar to the corresponding message described in clause 4.2.2.2 of 3GPP TS 23.502 V16.0.2, except that the Nudm_SDM_Get response at step 1008 may include an indication that the same SMF and the same PCF are required for multiple PDU sessions to the DNN and S-NSSAI, and the Npcf_AMPolicyControl_Create response at step 1012 may include an indication that the same SMF and the same PCF are required for multiple PDU sessions to the DNN and S-NSSAI.

[0107] Fig.11 FIG. 1 is a flow chart of a method according to another embodiment of the present disclosure. In this embodiment, the method can be implemented in 5GS. Fig.11 The message shown in is similar to the corresponding message described in clause 4.2.2.2 of 3GPP TS 23.502V16.0.2, except that in step 1a, AMF checks whether multiple PDU sessions for DNN and S-NSSAI require the same SMF and the same PCF. If so, AMF selects the same SMF. If so, AMF selects the same SMF, and AMF sends a new indication to SMF; in step 1b, AMF sends a PDU session establishment request to SMF, which includes a new indication that the same PCF should be selected for the PDU session; in step 1c, if a new indication is received, SMF selects the same PCF as the first PDU session of the UE to DNN and S-NSSAI.

[0108] Fig.12a A simplified block diagram of an apparatus 1210 that may be embodied in / as an access and mobility management node according to an embodiment of the present disclosure is illustrated. Figure 12bAn apparatus 1220 that may be embodied in / as a session management node according to an embodiment of the present disclosure is illustrated. Fig.12c An apparatus 1230 that may be embodied in / as a policy control node according to an embodiment of the present disclosure is illustrated. Fig.12d An apparatus 1240 that may be embodied in / serving as a data management node according to an embodiment of the present disclosure is illustrated.

[0109] The device 1210 may include at least one processor 1211, such as a data processor (DP), and at least one memory (MEM) 1212 coupled to the processor 1211. The device 1210 may also include a transmitter TX and a receiver RX 1213 coupled to the processor 1211. The MEM 1212 stores a program (PROG) 1214. The PROG 1214 may include instructions that, when executed on the associated processor 1211, enable the device 1210 to operate according to embodiments of the present disclosure, for example, to perform any method related to the access and mobility management node described above. The combination of at least one processor 1211 and at least one MEM 1212 may form a processing device 1215 suitable for implementing various embodiments of the present disclosure.

[0110] The device 1220 includes at least one processor 1221, such as a DP, and at least one MEM 1222 coupled to the processor 1221. The device 1220 may also include a transmitter TX and a receiver RX 1223 coupled to the processor 1221. The MEM 1222 stores a PROG 1224. The PROG 1224 may include instructions that, when executed on the associated processor 1221, enable the device 1220 to operate according to embodiments of the present disclosure, such as performing any method related to the session management node as described above. The combination of at least one processor 1221 and at least one MEM 1222 may form a processing device 1225 suitable for implementing various embodiments of the present disclosure.

[0111] The device 1230 may include at least one processor 1231, such as a data processor (DP), and at least one memory (MEM) 1232 coupled to the processor 1231. The device 1230 may also include a transmitter TX and a receiver RX 1233 coupled to the processor 1231. The MEM 1232 stores a program (PROG) 1234. The PROG 1234 may include instructions that, when executed on the associated processor 1231, enable the device 1230 to operate according to an embodiment of the present disclosure, such as performing any method related to the above-mentioned policy control node. The combination of at least one processor 1231 and at least one MEM 1232 may form a processing device 1235 suitable for implementing various embodiments of the present disclosure.

[0112] The device 1240 may include at least one processor 1241, such as a data processor (DP), and at least one memory (MEM) 1242 coupled to the processor 1241. The device 1240 may also include a transmitter TX and a receiver RX 1243 coupled to the processor 1241. The MEM 1242 stores a program (PROG) 1244. The PROG 1244 may include instructions that, when executed on the associated processor 1241, enable the device 1240 to operate according to an embodiment of the present disclosure, such as performing any method related to the above-mentioned data management node. The combination of at least one processor 1241 and at least one MEM 1242 may form a processing device 1245 suitable for implementing various embodiments of the present disclosure.

[0113] Various embodiments of the present disclosure may be implemented by a computer program, software, firmware, hardware, or a combination thereof that is executable by one or more of the processors 1211 , 1221 , 1231 , and 1241 .

[0114] MEMs 1212, 1222, 1232 and 1242 may be of any type suitable to the local technical environment and may be implemented using any suitable data storage technology such as, by way of non-limiting examples, semiconductor-based memory devices, magnetic memory devices and systems, optical memory devices and systems, fixed memory and removable memory.

[0115] Processors 1211, 1221, 1231 and 1241 may be of any type suitable for the local technical environment, and may include one or more of the following: as non-limiting examples, a general-purpose computer, a special-purpose computer, a microprocessor, a digital signal processor DSP, and a processor based on a multi-core processor architecture.

[0116] According to one aspect of the present disclosure, there is provided a computer program product tangibly stored on a computer-readable storage medium and comprising instructions, which, when executed on at least one processor, cause the at least one processor to perform any method related to the above-mentioned access and mobility management node.

[0117] According to one aspect of the present disclosure, there is provided a computer program product tangibly stored on a computer-readable storage medium and comprising instructions, which, when executed on at least one processor, cause the at least one processor to perform any method related to the above-mentioned session management node.

[0118] According to one aspect of the present disclosure, there is provided a computer program product tangibly stored on a computer-readable storage medium and comprising instructions, which, when executed on at least one processor, cause the at least one processor to perform any method related to the above-mentioned policy control node.

[0119] According to one aspect of the present disclosure, there is provided a computer program product tangibly stored on a computer-readable storage medium and comprising instructions, which, when executed on at least one processor, cause the at least one processor to perform any method related to the above-mentioned data management node.

[0120] According to one aspect of the present disclosure, there is provided a computer-readable storage medium storing instructions, which, when executed by at least one processor, causes the at least one processor to perform any method related to access and mobility management as described above.

[0121] According to one aspect of the present disclosure, a computer-readable storage medium storing instructions is provided. When the instructions are executed by at least one processor, the instructions cause the at least one processor to perform any method related to the session management node as described above.

[0122] According to one aspect of the present disclosure, a computer-readable storage medium storing instructions is provided. When the instructions are executed by at least one processor, the instructions cause the at least one processor to perform any method related to the policy control node as described above.

[0123] According to one aspect of the present disclosure, a computer-readable storage medium storing instructions is provided. When the instructions are executed by at least one processor, the instructions cause the at least one processor to perform any method related to the data management node as described above.

[0124] Many advantages can be achieved by applying the proposed solution according to the embodiments of the present disclosure. For example, the proposed solution can ensure that: the same session management node (e.g., SMF) is selected for multiple sessions (e.g., PDU sessions) of the UE to the same data network identified by the data network identifier (e.g., DNN and S-NSSAI), and then the same policy control node (e.g., PCF) is selected. The proposed solution can facilitate the monitoring of the usage of the data network identified by the data network identifier such as DNN and S-NSSAI for the UE, and ensure that the UE does not consume more than the quota allowed in its policy subscription.

[0125] In addition, the present disclosure may also provide a carrier containing the computer program as described above, wherein the carrier is one of the following: an electric signal, an optical signal, a radio signal or a computer-readable storage medium. The computer-readable storage medium may be, for example, an optical disc or an electronic storage device (such as RAM (random access memory), ROM (read-only memory), flash memory), a magnetic tape, a CD-ROM, a DVD, a Blu-ray disc, etc.

[0126] The techniques described herein may be implemented by various components, so that the device implementing one or more functions of the corresponding device described in the embodiments includes not only the components of the prior art, but also the components for implementing one or more functions of the corresponding device described in the embodiments, and it may include a separate component for each separate function or a component that can be configured to perform two or more functions. For example, these techniques may be implemented in hardware (one or more devices), firmware (one or more devices), software (one or more modules), or a combination thereof. For firmware or software, it may be implemented by a module (e.g., a process, a function, etc.) that performs the functions described herein.

[0127] The example embodiments of the present invention have been described above with reference to block diagrams and flowchart illustrations of methods and apparatus. It will be understood that each block of the block diagrams and flowcharts and combinations of blocks of the block diagrams and flowcharts can be implemented by various components including computer program instructions, respectively. These computer program instructions can be loaded onto a general-purpose computer, a special-purpose computer, or other programmable data processing device to produce a machine, so that the instructions executed on the computer or other programmable data processing device create components for implementing the functions specified in the flowchart block or blocks.

[0128] In addition, although the operations are depicted in a particular order, this should not be understood as requiring such operations to be performed in the particular order shown or in a continuous order, or performing all the operations shown, to achieve the desired result. In some cases, multitasking and parallel processing can be advantageous. Similarly, although several specific implementation details are included in the above discussion, these specific implementation details should not be interpreted as limitations on the scope of the subject matter described herein, but should be interpreted as descriptions of features that can be specific to a particular embodiment. Certain features described in the context of a separate embodiment may also be implemented in a single embodiment in combination. On the contrary, the various features described in the context of a single embodiment may also be implemented in multiple embodiments or in any suitable sub-combination, respectively.

[0129] Although this specification contains many specific implementation details, these should not be interpreted as limitations on the scope of any embodiment or the scope that may be claimed, but should be interpreted as descriptions of features of specific embodiments that may be specific to a particular embodiment. Certain features described in this specification in the context of separate embodiments may also be implemented in a single embodiment in combination. Conversely, the various features described in the context of a single embodiment may also be implemented in multiple embodiments or in any suitable sub-combination, respectively. Moreover, although features may be described above as working in certain combinations, and even initially claimed as such, in some cases, one or more features from the claimed combination may be removed from the combination, and the claimed combination may be directed to a sub-combination or a variation of a sub-combination.

[0130] It is obvious to those skilled in the art that, with the advancement of technology, the concept of the present invention can be implemented in various ways. The above embodiments are given to describe the present disclosure rather than to limit the present disclosure, and it should be understood that, as those skilled in the art will readily appreciate, modifications and variations can be made without departing from the spirit and scope of the present disclosure. Such modifications and variations are considered to be within the scope of the present disclosure and the appended claims. The scope of protection of the present disclosure is defined by the appended claims.

Claims

1. A method at an access and mobility management node, comprising: receiving, from a user equipment (UE), a request to establish another session to a data network identified by a data network identifier, wherein at least one existing session of the UE to the data network is already established; checking whether subscription data or policy data for the UE includes a first indication indicating that the same session management node is required for multiple sessions to the data network identified by the same data network identifier; When the subscription data or the policy data includes the first indication, selecting the same session management node as that used for the at least one existing session of the UE; as well as A session establishment request is sent to the selected session management node.

2. The method according to claim 1, wherein: The session establishment request includes a second indication to select the same policy control node as used for the at least one existing session.

3. The method according to claim 2, wherein: The session establishment request is a protocol data unit (PDU) session establishment request including the second indication.

4. The method according to any one of claims 1 to 3, wherein: The data network identifier is identified by a data network name (DNN) and single network slice selection auxiliary information (S-NSSAI).

5. The method according to any one of claims 1 to 3, further comprising: The subscription data is obtained from the data management node during a registration process of the UE or when the data management node updates the subscription data.

6. The method according to claim 5, wherein: The data management node is a unified data management (UDM) node.

7. The method according to claim 6, wherein: The subscription data is obtained from the Nudm_SDM_Get service operation or the Nudm_SDM_Notification service operation.

8. The method according to any one of claims 1-3 and 6-7, further comprising: The policy data is obtained from the policy control node during a registration procedure of the UE or when the policy control node updates the policy data.

9. The method according to claim 8, wherein: The policy data is obtained from the Npcf_AMPolicyControl_Create service operation and / or the Npcf_AMPolicyControl_Update service operation.

10. The method according to any one of claims 1-3, 6-7 and 9, wherein: The access and mobility management node is an access and mobility management function (AMF) node, and the session management node is a session management function (SMF) node.

11. The method according to claim 8, wherein: The policy control node is a Policy Control Function (PCF) node.

12. A method at a session management node, comprising: receiving a session establishment request from an access and mobility management node, the session establishment request comprising a second indication to select the same policy control node as for at least one existing session of a user equipment (UE), wherein the session establishment request is for establishing another session of the UE to a data network identified by a data network identifier, the at least one existing session of the UE to the data network having been established; as well as The same policy control node is selected as that used for the at least one existing session for the UE.

13. The method according to claim 12, wherein: The data network identifier is identified by a data network name (DNN) and single network slice selection auxiliary information (S-NSSAI).

14. The method according to claim 12 or 13, wherein: The session establishment request is a protocol data unit (PDU) session establishment request including the second indication.

15. The method according to claim 12 or 13, wherein: The access and mobility management node is an access and mobility management function (AMF) node, the session management node is a session management function (SMF) node, and the policy control node is a policy control function (PCF) node.

16. A method at a policy control node, comprising: obtaining policy data for a user equipment (UE), the policy data comprising a first indication indicating that a same session management node is required for multiple sessions of the UE to a data network identified by a data network identifier; as well as The policy data is stored.

17. The method according to claim 16, wherein: The data network identifier is identified by a data network name (DNN) and single network slice selection auxiliary information (S-NSSAI).

18. The method according to claim 16 or 17, further comprising: The policy data is sent to an access and mobility management node during a registration procedure of the UE or when the policy control node updates the policy data.

19. The method according to claim 18, wherein: The policy data is sent in the Npcf_AMPolicyControl_Create service operation and / or the Npcf_AMPolicyControl_Update service operation.

20. The method of claim 18, wherein the access and mobility management node is an access and mobility management function (AMF) node, and the policy control node is a policy control function (PCF) node.

21. The method according to any one of claims 16-17 and 19-20, wherein: The first indication further indicates that the same policy control node is required for the multiple sessions of the UE to the data network identified by the data network identifier.

22. A method at a data management node, comprising: Obtaining subscription data of a user equipment (UE), the subscription data comprising a first indication indicating that a same session management node is required for multiple sessions of the UE to a data network identified by a data network identifier; as well as The signing data is stored.

23. The method according to claim 22, wherein: The first indication further indicates that the multiple sessions for the UE to the data network identified by the data network identifier require the same policy control node.

24. The method according to claim 22 or 23, wherein: The data network identifier is identified by a data network name (DNN) and single network slice selection auxiliary information (S-NSSAI).

25. The method according to claim 22 or 23, further comprising: The subscription data is sent to an access and mobility management node during a registration procedure of the UE or when the data management node updates the subscription data.

26. The method according to claim 25, wherein: The subscription data is sent in a Nudm_SDM_Get service operation and / or a Nudm_SDM_Notification service operation.

27. The method according to claim 25, wherein: The access and mobility management node is an access and mobility management function (AMF) node, and the data management node is a unified data management (UDM) node.

28. An apparatus at an access and mobility management node, comprising: processor; as well as a memory coupled to the processor, the memory storing instructions executable by the processor, whereby the apparatus is operable to: receiving, from a user equipment (UE), a request to establish another session to a data network identified by a data network identifier, wherein at least one existing session of the UE to the data network is already established; checking whether subscription data or policy data for the UE includes a first indication indicating that the same session management node is required for multiple sessions to the data network identified by the same data network identifier; When the subscription data or the policy data includes the first indication, selecting the same session management node as that used for the at least one existing session of the UE; as well as A session establishment request is sent to the selected session management node.

29. The device according to claim 28, wherein The apparatus is further operable to perform a method according to any one of claims 2 to 11.

30. An apparatus at a session management node, comprising: processor; as well as a memory coupled to the processor, the memory storing instructions executable by the processor, whereby the apparatus is operable to: receiving a session establishment request from an access and mobility management node, the session establishment request comprising a second indication to select the same policy control node as for at least one existing session of a user equipment (UE), wherein the session establishment request is for establishing another session of the UE to a data network identified by a data network identifier, the at least one existing session of the UE to the data network having been established; as well as The same policy control node is selected as that used for the at least one existing session for the UE.

31. The device according to claim 30, wherein The apparatus is further operable to perform a method according to any one of claims 13 to 15.

32. An apparatus at a policy control node, comprising: processor; as well as a memory coupled to the processor, the memory storing instructions executable by the processor, whereby the apparatus is operable to: obtaining policy data for a user equipment (UE), the policy data comprising a first indication indicating that a same session management node is required for multiple sessions of the UE to a data network identified by a data network identifier; as well as The policy data is stored.

33. The device according to claim 32, wherein: The apparatus is further operable to perform a method according to any one of claims 17 to 21.

34. A device at a data management node, comprising: processor; as well as a memory coupled to the processor, the memory storing instructions executable by the processor, whereby the apparatus is operable to: Obtaining subscription data of a user equipment (UE), the subscription data comprising a first indication indicating that a same session management node is required for multiple sessions of the UE to a data network identified by a data network identifier; as well as The signing data is stored.

35. The device according to claim 34, wherein The apparatus is further operable to perform the method of any one of claims 23 to 27.

36. A computer-readable storage medium storing instructions which, when executed by at least one processor, cause the at least one processor to perform the method of any one of claims 1 to 27.

37. A computer program product comprising instructions which, when executed by at least one processor, cause the at least one processor to perform the method according to any one of claims 1 to 27.

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