A network slicing admission control method and apparatus

Abstract

This application provides a network slice admission control method and apparatus. The method includes: a first network element obtaining first information from a second network element, the first information being used to associate a first session of a user equipment (UE), the first network element supporting control over the number of users accessing the network slice, the first session being associated with the network slice, and the second network element serving the first session; the first network element receiving a first request message from the second network element, the first request message being used to instruct a reduction in the number of users already accessing the network slice; and the first network element determining, based on the first information, whether to reduce the number of users already accessing the network slice. This method enables control over the number of users accessing the network slice and the number of sessions established within the network slice, thus facilitating network slice admission control.

Description

Technical Field

[0001] This application relates to the field of communications, and more specifically, to a network slicing admission control method and apparatus. Background Technology

[0002] With the development of communication technology, hundreds of billions of IoT devices will be connected to the network. Different types of application scenarios have different, and sometimes even conflicting, network requirements. Using a single network to simultaneously provide services for different types of application scenarios would lead to an exceptionally complex network architecture and low network management and resource utilization efficiency. Network slicing technology provides isolated network environments for different application scenarios by creating virtual independent logical networks on the same network infrastructure. This allows different application scenarios to customize network functions and characteristics according to their own needs, effectively guaranteeing the quality of service (QoS) requirements of different services.

[0003] In real-world network slicing deployments, due to network resource limitations, the number of users a network slice can accommodate and the number of sessions it can establish are finite. Therefore, controlling the number of users accessing a network slice and the number of sessions established on that slice becomes a pressing issue. Summary of the Invention

[0004] This application provides a network slice admission control method and apparatus, which can control the number of users accessing a network slice and the number of sessions established in a network slice, thus facilitating network slice admission control.

[0005] In a first aspect, this application provides a network slice admission control method, the method comprising: a first network element obtaining first information from a second network element, the first information being used to associate a first session of a user equipment, the first network element supporting control over the number of users accessing the network slice, the first session being associated with the network slice, and the second network element serving the first session; the first network element receiving a first request message from the second network element, the first request message being used to instruct a reduction in the number of users already accessing the network slice; and the first network element determining, based on the first information, whether to reduce the number of users already accessing the network slice.

[0006] The first network element supports controlling the number of users accessing the network slice. It can also be described as the first network element supporting counting the number of UEs accessing the network slice or the first network element having the ability to control the number of users accessing the network slice.

[0007] The aforementioned first information is used to associate a first session of a user equipment, or it can be described as information related to a first session of a user equipment. As an example, the first information is used to identify the first session; for instance, the first information may include at least one of an identifier for the first session or an identifier for a second network element. The identifier for the second network element can be the ID of the second network element, and the identifier for the first session is used to identify the first session, such as a Protocol Data Unit (PDU) session ID.

[0008] Optionally, the first network element can be a network slice admission control function (NSACF) network element, and the second network element can be a session management function (SMF) + packet data network (PDN) gateway-control plane (PGW-C) network element, i.e., SMF+PGW-C.

[0009] In one possible implementation, after the first network element obtains the first information, it can also save the first information, the network slice, and the corresponding relationship of the user equipment.

[0010] In the above technical solution, the second network element sends session-related information to the first network element so that the first network element can store the correspondence between user equipment, network slices, and session-related information. When the first network element receives an instruction to reduce the number of users accessing the network slice, it can determine whether the number of users accessing the network slice can be reduced based on this correspondence. This enables network slice admission control.

[0011] In conjunction with the first aspect, in one possible implementation, the first network element obtains the first information from the second network element, including: the first network element obtaining the first information during the process of the second network element requesting an increase in the number of users already connected to the network slice.

[0012] For example, when a user equipment establishes a PDN connection in an evolved packet core (EPC) network, and a second network element determines the network slice corresponding to the PDN connection, thereby triggering user number control and session number control for the network slice, the second network element can first interact with a first network element that supports controlling the number of users accessing the network slice, triggering the first network element to increase the number of users accessing the network slice, and sending first information to the first network element during the interaction with the first network element; if the number of users accessing the network slice is not exceeded, it means that the number of users accessing the network slice has not reached the maximum number (such as the first threshold), and the network slice allows new users to access, and the second network element then interacts with a third network element that supports controlling the number of sessions established on the network slice, triggering the third network element to increase the number of sessions established on the network slice; if the second network element learns from the third network element that the network slice... If the number of sessions already established in a network slice has not exceeded the limit, it means that the number of sessions already established in that network slice has not reached the maximum number (such as the second threshold). In this case, the network slice allows the establishment of new sessions. This can also be understood as the second network element learning from the third network element that the session count control has been successful. In this case, the second network element can stop interacting with the first network element and continue to execute other steps of the PDN connection establishment process. If the second network element learns from the third network element that the number of sessions already established in that network slice has exceeded the limit, it means that the number of sessions already established in that network slice has reached the maximum number (such as the second threshold). In this case, the network slice does not allow the establishment of new sessions. This can also be understood as the second network element learning from the third network element that the session count control has failed. In this case, the second network element can interact with the first network element again to trigger the first network element to control the number of users accessing that network slice, such as triggering the first network element to reduce the number of users accessing that network slice.

[0013] In the above technical solution, the first network element obtains the first information during the process of the second network element requesting an increase in the number of users already connected to the network slice. In this way, when the second network element learns from the third network element that the session number control is successful, it does not need to interact with the first network element again, which helps to reduce signaling overhead.

[0014] In conjunction with the first aspect or any of its implementations, in another possible implementation, the first network element obtains first information from the second network element, including: if the number of sessions established on the network slice does not exceed the maximum number of sessions allowed to be established on the network slice, the first network element receives a second request message from the second network element, the second request message including the first information.

[0015] For example, when a user equipment establishes a PDN connection in an EPC network, and the second network element determines the network slice corresponding to the PDN connection, thereby triggering user number control and session number control for the network slice, the second network element can first interact with the first network element that supports controlling the number of users accessing the network slice, triggering the first network element to increase the number of users accessing the network slice. If the number of users accessing the network slice is not exceeded, it means that the number of users accessing the network slice has not reached the maximum number (such as the first threshold), and the network slice allows new users to access. The second network element then interacts with the third network element that supports controlling the number of sessions established on the network slice, triggering the third network element to increase the number of sessions established on the network slice. If the second network element learns from the third network element that the number of sessions already established on the network slice is not exceeded, it means that the number of sessions already established on the network slice... If the maximum number of sessions has not been reached (e.g., the second threshold), the network slice allows new sessions to be established. This can also be understood as the second network element learning from the third network element that session count control has been successful. In this case, the second network element can send a second request message to the first network element, carrying the first information in the second request message so that the first network element can store the first information and continue to execute other steps of the PDN connection establishment process. If the second network element learns from the third network element that the number of sessions already established in the network slice exceeds the limit, it means that the number of sessions already established in the network slice has reached the maximum number (e.g., the second threshold). In this case, the network slice does not allow new sessions to be established. This can also be understood as the second network element learning from the third network element that session count control has failed. In this case, the second network element can interact with the first network element again to trigger the first network element to control the number of users accessing the network slice, such as triggering the first network element to reduce the number of users accessing the network slice.

[0016] In the above technical solution, the first network element obtains the first information when the number of sessions established on the network slice does not exceed the maximum number of sessions allowed to be established on the network slice. In this way, when the second network element learns from the third network element that the session number control has failed, it is not necessary to instruct the first network element to delete the first information, which simplifies the process.

[0017] In conjunction with the first aspect or any of its implementations, in another possible implementation, the first network element determines whether to reduce the number of users already connected to the network slice based on the first information. This includes: if the user equipment has established a session on the network slice other than the first session, the first network element determines to maintain the number of users already connected to the network slice; if the user equipment has only established the first session on the network slice, the first network element determines to reduce the number of users already connected to the network slice. This allows for more accurate control over the number of users already connected to the network slice.

[0018] In conjunction with the first aspect or any of its implementations, in another possible implementation, the method further includes: after the first network element determines whether to reduce the number of users already connected to the network slice, the first network element deletes the first information.

[0019] In conjunction with the first aspect or any of its implementations, in another possible implementation, the first session is a PDN connection established by the user equipment in the EPC network, or it can also be described as the first session being the session corresponding to the PDN connection established by the user equipment in the EPC.

[0020] Secondly, this application provides a network slice admission control method, the method comprising: a second network element determining a network slice associated with a first session of a user equipment; the second network element sending first information to a first network element, the first information being used to associate the first session, the first network element supporting control over the number of users accessing the network slice, the second network element serving the first session; the second network element sending a first request message to the first network element, the first request message being used to instruct a reduction in the number of users already accessing the network slice; wherein, the first information is used to determine whether to reduce the number of users already accessing the network slice.

[0021] The second network element serves the first session. This can be understood as the second network element being associated with the first session when it is established, or the first session being established through the network slice resources supported by the second network element.

[0022] The network slice associated with the first session can be understood as the network slice on which the first session is established, or the network slice used to establish the first session.

[0023] The first network element supports controlling the number of users accessing the network slice. It can also be described as the first network element supporting counting the number of users accessing the network slice or the first network element having the ability to control the number of users accessing the network slice.

[0024] The aforementioned first information is used to associate a first session of a user equipment, and can also be described as information related to a first session of a user equipment. As an example, the first information is used to identify the first session; for instance, the first information may include at least one of an identifier for the first session or an identifier for a second network element. The identifier for the second network element may be the ID of the second network element, and the identifier for the first session is used to identify the first session, such as a PDU session ID.

[0025] Optionally, the first network element can be NSACF, and the second network element can be SMF+PGW-C.

[0026] In the above technical solution, the second network element sends session-related information to the first network element so that the first network element can store the correspondence between user equipment, network slices, and session-related information. Therefore, when the first network element receives an instruction to reduce the number of users accessing the network slice, it can determine whether the number of users accessing the network slice can be reduced based on this correspondence. This enables network slice admission control.

[0027] In conjunction with the second aspect, in one possible implementation, the second network element sends the first information to the first network element, including: during the process of requesting an increase in the number of users already connected to the network slice, the second network element sends the first information to the first network element.

[0028] For example, when a user equipment establishes a PDN connection in an EPC network, and a second network element determines the network slice corresponding to the PDN connection, thereby triggering user number control and session number control for the network slice, the second network element can first interact with a first network element that supports controlling the number of users accessing the network slice, triggering the first network element to increase the number of users accessing the network slice, and sending first information to the first network element during the interaction with the first network element; if the number of users accessing the network slice is not exceeded, it means that the number of users accessing the network slice has not reached the maximum number (such as the first threshold), then the network slice allows new users to access, and the second network element then interacts with a third network element that supports controlling the number of sessions established on the network slice, triggering the third network element to increase the number of sessions established on the network slice; if the second network element learns from the third network element that the network slice has not exceeded the limit, it means that the number of users accessing the network slice has not reached the maximum number (such as the first threshold), then the network slice allows new users to access, and the second network element then interacts with a third network element that supports controlling the number of sessions established on the network slice, triggering the third network element to increase the number of sessions established on the network slice; if the second network element learns from the third network element that the network slice has not exceeded the limit, it can then further interact with the third network element to control the number of users accessing the network slice. If the number of sessions already established in a network slice is not exceeded, it means that the number of sessions already established in that network slice has not reached the maximum number (such as the second threshold). In this case, the network slice allows the establishment of new sessions. This can also be understood as the second network element learning from the third network element that the session count control has been successful. In this case, the second network element can stop interacting with the first network element and continue to execute other steps of the PDN connection establishment process. If the second network element learns from the third network element that the number of sessions already established in that network slice has exceeded the limit, it means that the number of sessions already established in that network slice has reached the maximum number (such as the second threshold). In this case, the network slice does not allow the establishment of new sessions. This can also be understood as the second network element learning from the third network element that the session count control has failed. In this case, the second network element can interact with the first network element again to trigger the first network element to control the number of users accessing that network slice, such as triggering the first network element to reduce the number of users accessing that network slice.

[0029] In the above technical solution, the first network element obtains the first information during the process of the second network element requesting an increase in the number of users already connected to the network slice. In this way, when the second network element learns from the third network element that the session number control is successful, it does not need to interact with the first network element again, which helps to reduce signaling overhead.

[0030] In conjunction with the second aspect or any of its implementations, in another possible implementation, the second network element sends first information to the first network element, including: when the number of sessions established on the network slice does not exceed the maximum number of sessions allowed to be established on the network slice, the second network element sends a second request message to the first network element, the second request message including the first information.

[0031] For example, when a user equipment establishes a PDN connection in an EPC network, and the second network element determines the network slice corresponding to the PDN connection, thereby triggering user number control and session number control for the network slice, the second network element can first interact with the first network element that supports controlling the number of users accessing the network slice, triggering the first network element to increase the number of users accessing the network slice. If the number of users accessing the network slice is not exceeded, it means that the number of users accessing the network slice has not reached the maximum number (such as the first threshold), and the network slice allows new users to access. The second network element then interacts with the third network element that supports controlling the number of sessions established on the network slice, triggering the third network element to increase the number of sessions established on the network slice. If the second network element learns from the third network element that the number of sessions already established on the network slice is not exceeded, it means that the number of sessions already established on the network slice... If the maximum number of sessions has not been reached (e.g., the second threshold), the network slice allows new sessions to be established. This can also be understood as the second network element learning from the third network element that session count control has been successful. In this case, the second network element can send a second request message to the first network element, carrying the first information in the second request message so that the first network element can store the first information and continue to execute other steps of the PDN connection establishment process. If the second network element learns from the third network element that the number of sessions already established in the network slice exceeds the limit, it means that the number of sessions already established in the network slice has reached the maximum number (e.g., the second threshold). In this case, the network slice does not allow new sessions to be established. This can also be understood as the second network element learning from the third network element that session count control has failed. In this case, the second network element can interact with the first network element again to trigger the first network element to control the number of users accessing the network slice, such as triggering the first network element to reduce the number of users accessing the network slice.

[0032] In the above technical solution, the first network element obtains the first information when the number of sessions established on the network slice does not exceed the maximum number of sessions allowed to be established on the network slice. In this way, when the second network element learns from the third network element that the session number control has failed, it is not necessary to instruct the first network element to delete the first information, which simplifies the process.

[0033] In conjunction with the second aspect or any of its implementations, in another possible implementation, the method further includes: the second network element learning from the third network element that the number of sessions established on the network slice has reached the maximum number of sessions allowed to be established on the network slice, wherein the third network element supports controlling the number of sessions established on the network slice; the second network element sending a first request message to the first network element, including: after the second network element learns that the number of sessions established on the network slice has reached the maximum number of sessions allowed to be established on the network slice, the second network element sends the first request message to the first network element.

[0034] In conjunction with the second aspect or any of its implementations, in another possible implementation, the second network element sends a first request message to the first network element, including: when releasing the first session, the second network element sends the first request message to the first network element.

[0035] In conjunction with the second aspect or any of its implementations, in another possible implementation, the first session is a PDN connection established by the user equipment in the EPC network, or it can also be described as the first session being the session corresponding to the PDN connection established by the user equipment in the EPC.

[0036] Thirdly, this application provides a network slice admission control method, the method comprising: a second network element determining a network slice associated with a first session of a user equipment; the second network element sending a third request message to a network storage function network element, the third request message being used to request information from a fourth network element, the third request message including an identifier of the network slice and second information, the second information being used to instruct the fourth network element to support control over the number of users accessing the network slice and to support control over the number of sessions established on the network slice; the second network element receiving a third response message from the network storage function network element, the third response message including information from the fourth network element; and the second network element sending a fourth request message to the fourth network element, the fourth request message being used to request the fourth network element to control over the number of users accessing the network slice and to control over the number of sessions established on the network slice.

[0037] In the above technical solution, the second network element requests the network storage function network element to select a fourth network element that simultaneously supports controlling the number of users accessing the network slice and controlling the number of sessions established on the network slice. This allows the fourth network element to determine, when identifying the number of users and sessions corresponding to a network slice, whether the user equipment has already accessed the network slice or whether all of the user equipment's sessions should be released, thereby accurately controlling the number of users accessing the network slice and the number of sessions established on the network slice. This achieves network slice admission control.

[0038] In conjunction with the third aspect, in one possible implementation, the fourth request message includes the identifier of the user equipment, first information, third information, fourth information, and the identifier of the network slice. The first information is used to associate the first session, wherein: when the user equipment requests to establish the first session, the third information is used to indicate an increase in the number of users already connected to the network slice, and the fourth information is used to indicate an increase in the number of sessions already established in the network slice; when the user equipment requests to release the first session, the third information is used to indicate a decrease in the number of users already connected to the network slice, and the fourth information is used to indicate a decrease in the number of sessions already established in the network slice.

[0039] In conjunction with the third aspect or any of its implementations, in another possible implementation, the first information includes at least one of the identifier of the second network element or the identifier of the first session.

[0040] In conjunction with the third aspect or any of its implementations, in another possible implementation, the first session is a PDN connection established by the user equipment in the EPC network, or it can also be described as the first session being the session corresponding to the PDN connection established by the user equipment in the EPC.

[0041] Fourthly, this application provides a network slice admission control method, the method comprising: a network storage function network element receiving a third request message from a second network element, the third request message being used to request information from a fourth network element, the third request message including an identifier of the network slice and second information, the second information being used to instruct the fourth network element to support controlling the number of users accessing the network slice and to support controlling the number of sessions established on the network slice; the network storage function network element sending a third response message to the second network element, the third response message including information from the fourth network element.

[0042] In the above technical solution, the second network element requests the network storage function network element to select a fourth network element that simultaneously supports controlling the number of users accessing the network slice and controlling the number of sessions established on the network slice. This allows the fourth network element to determine, when identifying the number of users and sessions corresponding to a network slice, whether the user equipment has already accessed the network slice or whether all of the user equipment's sessions should be released, thereby accurately controlling the number of users accessing the network slice and the number of sessions established on the network slice. This achieves network slice admission control.

[0043] Fifthly, this application provides a network slice admission control method, the method comprising: a fourth network element receiving a fourth request message from a second network element, the fourth network element supporting control over the number of users accessing the network slice and supporting control over the number of sessions established on the network slice, the second network element serving a first session of a user equipment, the first session being associated with the network slice; the fourth network element performing control over the number of users already accessing the network slice and the number of sessions already established on the network slice according to the fourth request message; and the fourth network element sending a fourth response message to the second network element, the fourth response message indicating the result of performing control over the number of users already accessing the network slice and the result of performing control over the number of sessions already established on the network slice.

[0044] In the above technical solution, the second network element requests the network storage function network element to select a fourth network element that simultaneously supports controlling the number of users accessing the network slice and controlling the number of sessions established on the network slice. This allows the fourth network element to determine, when identifying the number of users and sessions corresponding to a network slice, whether the user equipment has already accessed the network slice or whether all of the user equipment's sessions should be released, thereby accurately controlling the number of users accessing the network slice and the number of sessions established on the network slice. This achieves network slice admission control.

[0045] In conjunction with the fifth aspect, in one possible implementation, the fourth request message includes an identifier of the user equipment, first information, third information, fourth information, and an identifier of the network slice. The first information is used to associate the first session, wherein: when the user equipment requests to establish the first session, the third information is used to indicate an increase in the number of users already connected to the network slice, and the fourth information is used to indicate an increase in the number of sessions already established in the network slice; when the user equipment requests to release the first session, the third information is used to indicate a decrease in the number of users already connected to the network slice, and the fourth information is used to indicate a decrease in the number of sessions already established in the network slice.

[0046] Sixthly, this application provides a communication device, the device comprising:

[0047] The transceiver unit is configured to obtain first information from a second network element, the first information being used to associate a first session of a user equipment, the first network element supporting control over the number of users accessing a network slice, the first session being associated with the network slice, and the second network element serving the first session; and to receive a first request message from the second network element, the first request message being used to instruct a reduction in the number of users already accessing the network slice.

[0048] The processing unit is configured to determine, based on the first information, whether to reduce the number of users already connected to the network slice.

[0049] In one possible implementation, after obtaining the first information, the device can also save the first information, the network slice, and the corresponding relationship of the user equipment.

[0050] In conjunction with the sixth aspect, in one possible implementation, the transceiver unit is specifically used to: obtain the first information during the process of the second network element requesting an increase in the number of users already connected to the network slice.

[0051] In conjunction with the sixth aspect or any of its implementations, in another possible implementation, the transceiver unit is specifically configured to: receive a second request message from the second network element, wherein the second request message includes the first information, provided that the number of sessions established on the network slice does not exceed the maximum number of sessions allowed to be established on the network slice.

[0052] In conjunction with the sixth aspect or any of its implementations, in another possible implementation, the processing unit is specifically configured to: if the user equipment establishes a session other than the first session on the network slice, determine to maintain the number of users already connected to the network slice; if the user equipment establishes only the first session on the network slice, determine to reduce the number of users already connected to the network slice.

[0053] In conjunction with the sixth aspect or any of its implementations, in another possible implementation, the processing unit is further configured to: delete the first information after determining whether to reduce the number of users already connected to the network slice.

[0054] In conjunction with the sixth aspect or any of its implementations, in another possible implementation, the first session is a PDN connection established by the user equipment in the EPC network.

[0055] In a seventh aspect, this application provides a communication device, the device comprising:

[0056] Processing unit, used to determine the network slice associated with the first session of the user equipment;

[0057] The transceiver unit is configured to send first information to a first network element, the first information being associated with the first session, the first network element supporting control over the number of users accessing the network slice, and a second network element serving the first session; and to send a first request message to the first network element, the first request message being used to instruct a reduction in the number of users already accessing the network slice; wherein, the first information is used to determine whether to reduce the number of users already accessing the network slice.

[0058] In conjunction with the seventh aspect, in one possible implementation, the transceiver unit is specifically used to: send the first information to the first network element during the process of requesting an increase in the number of users already connected to the network slice.

[0059] In conjunction with the seventh aspect or any of its implementations, in another possible implementation, the transceiver unit is specifically configured to: send a second request message to the first network element when the number of sessions established on the network slice does not exceed the maximum number of sessions allowed to be established on the network slice, the second request message including the first information.

[0060] In conjunction with the seventh aspect or any of its implementations, in another possible implementation, the transceiver unit is specifically configured to: learn from a third network element that the number of sessions established on the network slice has reached the maximum number of sessions allowed to be established on the network slice, wherein the third network element supports control over the number of sessions established on the network slice; and after the second network element learns that the number of sessions established on the network slice has reached the maximum number of sessions allowed to be established on the network slice, send the first request message to the first network element.

[0061] In conjunction with the seventh aspect or any of its implementations, in another possible implementation, the transceiver unit is specifically used to: when the first session is released, the second network element sends the first request message to the first network element.

[0062] In conjunction with the seventh aspect or any of its implementations, in another possible implementation, the first session is a PDN connection established by the user equipment in the EPC network.

[0063] Eighthly, this application provides a communication device, the device comprising:

[0064] Processing unit, used to determine the network slice associated with the first session of the user equipment;

[0065] The transceiver unit is configured to send a third request message to a network storage function network element, the third request message being used to request information from a fourth network element, the third request message including the identifier of the network slice and second information, the second information being used to instruct the fourth network element to support controlling the number of users accessing the network slice and to support controlling the number of sessions established on the network slice; receive a third response message from the network storage function network element, the third response message including information from the fourth network element; and send a fourth request message to the fourth network element, the fourth request message being used to request the fourth network element to control the number of users accessing the network slice and to control the number of sessions established on the network slice.

[0066] In conjunction with the eighth aspect, in one possible implementation, the fourth request message includes an identifier of the user equipment, first information, third information, fourth information, and an identifier of the network slice. The first information is used to associate the first session, wherein: when the user equipment requests to establish the first session, the third information is used to indicate an increase in the number of users already connected to the network slice, and the fourth information is used to indicate an increase in the number of sessions already established in the network slice; when the user equipment requests to release the first session, the third information is used to indicate a decrease in the number of users already connected to the network slice, and the fourth information is used to indicate a decrease in the number of sessions already established in the network slice.

[0067] In conjunction with the eighth aspect or any of its implementations, in another possible implementation, the first information includes at least one of the identifier of the second network element or the identifier of the first session.

[0068] In conjunction with the eighth aspect or any of its implementations, in another possible implementation, the first session is a PDN connection established by the user equipment in the EPC network.

[0069] Ninthly, this application provides a communication device, the device comprising:

[0070] The transceiver unit is configured to receive a third request message from a second network element, the third request message being used to request information from a fourth network element, the third request message including the identifier of the network slice and second information, the second information being used to instruct the fourth network element to support controlling the number of users accessing the network slice and to support controlling the number of sessions established on the network slice; and to send a third response message to the second network element, the third response message including information from the fourth network element.

[0071] In a tenth aspect, this application provides a communication device, the device comprising:

[0072] The transceiver unit is used to receive a fourth request message from a second network element. The fourth network element supports controlling the number of users accessing the network slice and controlling the number of sessions established on the network slice. The second network element serves a first session of the user equipment, and the first session is associated with the network slice.

[0073] The processing unit is configured to control the number of users who have accessed the network slice and the number of sessions that have been established in the network slice according to the fourth request message.

[0074] The transceiver unit is further configured to send a fourth response message to the second network element, the fourth response message being used to indicate the result of the control performed on the number of users already connected to the network slice and the result of the control performed on the number of sessions already established in the network slice.

[0075] In conjunction with the tenth aspect, in one possible implementation, the fourth request message includes an identifier of the user equipment, first information, third information, fourth information, and an identifier of the network slice. The first information is used to associate the first session, wherein: when the user equipment requests to establish the first session, the third information is used to indicate an increase in the number of users already connected to the network slice, and the fourth information is used to indicate an increase in the number of sessions already established in the network slice; when the user equipment requests to release the first session, the third information is used to indicate a decrease in the number of users already connected to the network slice, and the fourth information is used to indicate a decrease in the number of sessions already established in the network slice.

[0076] The sixth to tenth aspects are device embodiments corresponding to the first to fifth aspects, which can realize the methods described in the first to fifth aspects and achieve the beneficial effects described in the first to fifth aspects. For specific descriptions, please refer to the first to fifth aspects, which will not be repeated here.

[0077] Eleventhly, this application provides a communication device including a processor. The processor is coupled to a memory and can be used to execute instructions in the memory to cause the device to perform the methods provided in any one of the first to fifth aspects, or to perform the methods in any possible implementation of the first to fifth aspects. Optionally, the device further includes a memory. Optionally, the device further includes interface circuitry, and the processor is coupled to the interface circuitry.

[0078] In a twelfth aspect, this application provides a processor, including: an input circuit, an output circuit, and a processing circuit. The processing circuit is configured to receive signals through the input circuit and transmit signals through the output circuit, causing the processor to execute the method provided in any one of the first to fifth aspects, or to execute the method in any possible implementation of the first to fifth aspects.

[0079] In specific implementation, the processor can be a chip, the input circuit can be an input pin, the output circuit can be an output pin, and the processing circuit can be a transistor, gate circuit, flip-flop, and various logic circuits. The input signal received by the input circuit can be received and input by, for example, but not limited to, a receiver, and the signal output by the output circuit can be output to, for example, but not limited to, a transmitter and transmitted by the transmitter. Furthermore, the input circuit and the output circuit can be the same circuit, which is used as the input circuit and the output circuit at different times. This application does not limit the specific implementation of the processor and various circuits.

[0080] In a thirteenth aspect, this application provides a processing apparatus, including a processor and a memory. The processor is configured to read instructions stored in the memory, receive signals via a receiver, and transmit signals via a transmitter to execute the method provided in any one of the first to fifth aspects, or to execute the method in any possible implementation of the first to fifth aspects.

[0081] Optionally, the processor may be one or more, and the memory may be one or more.

[0082] Alternatively, the memory can be integrated with the processor, or the memory can be set separately from the processor.

[0083] In specific implementation, the memory can be a non-transitory memory, such as read-only memory (ROM), which can be integrated with the processor on the same chip or set on different chips. The embodiments of this application do not limit the type of memory or the way the memory and processor are set.

[0084] The processing device in the thirteenth aspect above can be a chip. The processor can be implemented in hardware or software. When implemented in hardware, the processor can be a logic circuit or an integrated circuit. When implemented in software, the processor can be a general-purpose processor that reads software code stored in a memory. The memory can be integrated into the processor or located outside the processor and exist independently.

[0085] In a fourteenth aspect, this application provides a computer program product comprising: a computer program (also referred to as code or instructions) that, when run, causes a computer to perform the method provided in any one of the first to fifth aspects, or to perform the method in any one of the possible implementations of the first to fifth aspects.

[0086] In a fifteenth aspect, this application provides a computer-readable medium storing a computer program (also referred to as code or instructions) that, when run on a computer, causes the computer to perform the method provided in any of the first to fifth aspects, or to perform the method in any of the possible implementations of the first to fifth aspects.

[0087] In a sixteenth aspect, this application provides a communication system including at least one of the means provided in any of the foregoing aspects or possible implementations thereof. Attached Figure Description

[0088] Figure 1 This is a schematic architecture diagram of a communication system that can be applied to this application.

[0089] Figure 2 This is another schematic architecture diagram of a communication system that can be applied to this application.

[0090] Figure 3 This is another schematic architecture diagram of a communication system that can be applied to this application.

[0091] Figure 4 This is a schematic flowchart of the network slice admission control method provided in this application.

[0092] Figure 5 This is a schematic flowchart of another network slice admission control method provided in this application.

[0093] Figure 6 This is an example of the network slice admission control method provided in this application.

[0094] Figure 7 This is another example of the network slice admission control method provided in this application.

[0095] Figure 8 This is another example of the network slice admission control method provided in this application.

[0096] Figure 9 This is another example of the network slice admission control method provided in this application.

[0097] Figure 10 This is another example of the network slice admission control method provided in this application.

[0098] Figure 11 This is a schematic diagram of the structure of the device provided in the embodiments of this application.

[0099] Figure 12 This is another schematic diagram of the device provided in the embodiments of this application. Detailed Implementation

[0100] The technical solutions in this application will now be described with reference to the accompanying drawings.

[0101] The technical solutions of this application embodiment can be applied to various communication systems, such as: Long Term Evolution (LTE) systems, LTE Frequency Division Duplex (FDD) systems, LTE Time Division Duplex (TDD) systems, Universal Mobile Telecommunication System (UMTS), Worldwide Interoperability for Microwave Access (WiMAX) systems, 5th Generation (5G) systems, New Radio (NR) systems, or satellite communication systems. The communication system may include non-standalone (NSA) and / or standalone (SA) networking.

[0102] The technical solutions provided in this application can also be applied to machine-type communication (MTC), Long Term Evolution-machine (LTE-M) communication, device-to-device (D2D) networks, machine-to-machine (M2M) networks, Internet of Things (IoT) networks, or other networks. Among these, IoT networks may include, for example, vehicle-to-everything (V2X) networks.

[0103] The technical solutions provided in this application can also be applied to future mobile communication systems, such as the sixth-generation mobile communication system, but this application does not limit them.

[0104] The following is based on Figures 1 to 3 For example, a communication system to which this application can be applied will be described.

[0105] Figure 1 This is a schematic architecture diagram of a communication system that can be applied to this application. Figure 1 This is a schematic diagram of a 5G network architecture based on a service-oriented architecture. Figure 1The 5G network architecture shown can be divided into three parts: user equipment (UE), data network (DN), and operator network. The operator network can include one or more of the following network elements: radio access network (RAN), user plane function (UPF) element, authentication server function (AUSF) element, NSACF element, access and mobility management function (AMF) element, SMF element, network slice selection function (NSSF) element, network exposure function (NEF) element, network repository function (NRF) element, policy control function (PCF) element, unified data management (UDM) element, and application function (AF) element. The portion of the operator network excluding the RAN can be referred to as the core network. In the following text, user equipment, radio access network, UPF network element, AUSF network element, AMF network element, SMF network element, NEF network element, NRF network element, PCF network element, UDM network element, NSSF network element, NSACF network element, and AF network element will be referred to as UE, RAN, UPF, DN, AUSF, AMF, SMF, NEF, NRF, PCF, UDM, NSSF, NSACF, and AF, respectively.

[0106] In this network architecture, Nnssf is the service-based interface presented by NSSF, Nnef is the service-based interface presented by NEF, Nnrf is the service-based interface presented by NRF, Npcf is the service-based interface presented by PCF, Nudm is the service-based interface presented by UDM, Naf is the service-based interface presented by AF, Nausf is the service-based interface presented by AUSF, Namf is the service-based interface presented by AMF, Nsmf is the service-based interface presented by SMF, and Nnsacf is the service-based interface presented by NSACF. N1 is the interface between UE and AMF; N2 is the interface between RAN and AMF, used for sending NAS messages; N3 is the interface between RAN and UPF, used for transmitting user plane data; N4 is the interface between SMF and UPF, used for transmitting information such as tunnel identification information for N3 connection, data buffer indication information, and downlink data notification messages; N6 is the interface between UPF and DN, used for transmitting user plane data; and N9 is the interface between UPFs.

[0107] The following is about Figure 1 The network elements involved are briefly described.

[0108] 1. UE

[0109] The UE primarily accesses the 5G network and obtains services through the radio air interface. The UE interacts with the RAN through the air interface and with the AMF of the core network through non-access stratum signaling (NAS).

[0110] In the embodiments of this application, the UE can also be referred to as terminal equipment, user, access terminal, user unit, user station, mobile station, mobile station, remote station, remote terminal, mobile device, user terminal, terminal, wireless communication equipment, user agent, or user device. UE can be a cellular phone, smartwatch, wireless data card, mobile phone, tablet computer, personal digital assistant (PDA) computer, wireless modem, handheld device, laptop computer, machine type communication (MTC) terminal, computer with wireless transceiver capability, Internet of Things (IoT) terminal, virtual reality terminal device, augmented reality terminal device, wearable device, vehicle, terminal in device-to-device (D2D) communication, terminal in vehicle-to-everything (V2X) communication, terminal in machine-type communication (MTC), terminal in Internet of Things (IoT), terminal in smart office, terminal in industrial control, terminal in autonomous driving, terminal in remote surgery, terminal in smart grid, terminal in transportation safety, terminal in smart city, terminal in smart home, or terminal in satellite communication (e.g., satellite phone or satellite terminal). The UE can also be a customer-premises equipment (CPE), a telephone, a router, a network switch, a residential gateway (RG), a set-top box, a fixed-mobile converged product, a home network adapter, and an internet access gateway. The embodiments of this application do not limit the specific technologies or device forms used in the UE.

[0111] 2. Access network equipment

[0112] The access network equipment in this application can be a device used for communication with the UE, primarily responsible for radio resource management, quality of service management, data compression, and encryption functions on the air interface side. This access network equipment can be a base station (BTS) in a Global System for Mobile Communication (GSM) or Code Division Multiple Access (CDMA) system, a base station (nodeB, NB) in a Wideband Code Division Multiple Access (WCDMA) system, an evolved NodeB (eNB or eNodeB) in an LTE system, a base station in a Worldwide Interoperability for Microwave Access (WiMAX) communication system, a radio controller in a cloud radio access network (CRAN) scenario, an access point in a wireless fidelity system, a relay station, vehicle-mounted equipment, or a wearable device. Alternatively, the access network equipment can be a terminal performing base station functions in D2D or machine-to-machine communication. Alternatively, the access network equipment can be a network device in a 5G network or a network device in a future evolved PLMN network. Furthermore, the access network equipment can also be a module or unit that performs some of the functions of the base station. For example, it can be a central unit (CU) or a distributed unit (DU). The embodiments of this application do not limit the specific technology or specific equipment form used in the access network equipment.

[0113] 3. UPF

[0114] UPF is a user plane function network element that supports all or some of the following functions: interconnecting protocol data unit (PDU) sessions with DNs; packet routing and forwarding (e.g., supporting uplink classifiers for traffic before forwarding to DNs, and supporting branching points to support multi-homed PDU sessions); and packet inspection.

[0115] 4. DN

[0116] The DN is the destination for a user's PDU session. The DN is the operator's network that provides data transmission services to users, such as Internet Protocol (IP) multimedia services (IMS) and the Internet. The UE can access the DN by establishing a PDU session between the UE, RAN, UPF, and DN.

[0117] 5. AUSF

[0118] AUSF is a core network control plane element, mainly responsible for authenticating and authorizing users to ensure that users are legitimate.

[0119] 6. AMF

[0120] AMF is a mobility management function network element responsible for user mobility management, including mobility state management, assigning temporary user identities, authenticating and authorizing users.

[0121] 7. SMF

[0122] SMF is a session management function network element responsible for user plane network element selection, user plane network element redirection, IP address allocation, bearer establishment, modification and release, and QoS control.

[0123] 8. NEF

[0124] The NEF (Network Element Framework) is a core network control plane element responsible for exposing mobile network capabilities and services to the outside world.

[0125] 9. NRF

[0126] NRFs belong to the core network control plane network elements and are responsible for the registration and discovery functions of network elements, as well as maintaining information about the network elements, such as the instance identifier, type, PLMN, slice-related identifier, IP address or FQDN, the capabilities of the network element, and the services it supports.

[0127] 10. PCF

[0128] PCF includes policy control decision-making and flow-based charging control functions, including user subscription data management, policy control, charging policy control, and QoS control. It mainly supports providing a unified policy framework to control network behavior, providing policy rules to the control layer network functions, and is also responsible for obtaining user subscription information related to policy decisions.

[0129] 11. UDM

[0130] UDM is a core network control plane element belonging to the user server. It is responsible for managing subscription data and notifying the relevant network elements when the subscription data is modified.

[0131] 12. NSSF

[0132] NSSF is responsible for selecting network slices.

[0133] 13. NSACF

[0134] The NSACF is responsible for admission control of network slices. For example, when admission control is required for a network slice, the NSACF can control the number of users accessing each network slice. The maximum number of UEs per network slice can be configured on the NSACF. When increasing the number of currently registered users in a network slice, the NSACF first determines whether the number of currently connected users in that network slice has reached the maximum number of users for that network slice.

[0135] NSACF can also control the number of sessions established on each network slice. The maximum number of PDU sessions per network slice can be configured on NSACF. When increasing the current number of sessions on a network slice, NSACF first determines whether the number of sessions already established on that network slice has reached the maximum number of sessions for that network slice.

[0136] 14. AF

[0137] The Application Provider (AF) is responsible for providing certain application-layer services to the User Equipment (UE). When providing services to the UE, the AF has requirements for QoS (policy) and charging policies, and needs to notify the network. At the same time, the AF also needs application-related information from the core network.

[0138] Figure 2 This is another schematic architecture diagram of a communication system that can be applied to this application. Figure 2 This is a schematic diagram of a 5G network architecture based on a point-to-point interface. Figure 2 and Figure 1 The main difference is Figure 2 The interfaces between the various network elements are point-to-point interfaces, not service-oriented interfaces. Descriptions of each network element can be found in [reference needed]. Figure 1 This will not be elaborated upon here.

[0139] Figure 3 This is another schematic architecture diagram of a communication system that can be applied to this application. Figure 3 It is used in fifth-generation communication systems (5G). thA non-roaming architecture for interoperability between the EPS (Evolved Universal Terrestrial Radio Access Network) and the 5G generation system (5GS) and the EPC / evolved universal terrestrial radio access network (e-UTRAN). In this architecture, some network elements of the EPC network and some network elements of the 5G network can be deployed on the same physical entity, enabling the EPS network and the 5G network to interact. For example... Figure 3 As shown, the Home Subscriber Server (HSS) network element and the Unified Data Management (UDM) network element can be deployed on the same physical entity. The Control Plane Function (PGW-C) and Session Management Function (SMF) network elements of the Packet Data Network Gateway (PGW) can be deployed on the same physical entity. The User Plane Function (PGW-U) and User Plane Function (UPF) network elements of the Packet Data Network Gateway (PGW) can be deployed on the same physical entity. These network elements can also be separate network elements; this embodiment does not limit this. The N26 interface is an inter-CN interface between the Mobility Management Entity (MME) and the 5GS AMF, used to achieve interoperability between the EPC and the 5G core network. Supporting the N26 interface is optional for achieving interoperability between 5GS and EPC / E-UTRAN. N26 supports a subset of the functions supported by S10 (basic interconnection functions). HSS+UDM network elements are network elements with both HSS and UDM network element functions, capable of storing user subscription data. For example, user subscription data includes mobility management-related subscription data and session management-related subscription data. The HSS+UDM network element can also be referred to as an HSS+UDM device, HSS+UDM entity, UDM+HSS network element, UDM+HSS device, or UDM+HSS entity. SMF+PGW-C network elements have SMF and PGW-C functions, while UPF+PGW-C network elements have UPF and PGW-U functions. UEs camped on the EPC can obtain 5G core network services or EPC services through SMF+PGW-C when establishing a PDN connection. Figure 3 The 5G component involved can be... Figure 1 or Figure 2 As shown.

[0140] It should be understood that Figures 1 to 3 The names given for each network element shown are merely names and do not limit the function of the network element itself. In different networks, these network elements may have other names, and this embodiment does not specifically limit this. For example, in a 6G network, some or all of the above network elements may use the terminology from 5G, or they may have other names, etc. This is explained uniformly here and will not be repeated below. Similarly, Figures 1 to 3 The interfaces between network elements shown are merely examples. In 5G networks and other future networks, the interfaces between network elements may not be those shown in the figure, and this application does not limit this. It should also be understood that the embodiments of this application are not limited to... Figures 1 to 3 In the system architecture shown. For example, a communication system to which this application can be applied may include more or fewer network elements or devices. Figures 1 to 3 The devices or network elements in the network can be hardware, software based on function, or a combination of both. Figures 1 to 3 Devices or network elements within the network can communicate with each other through other devices or network elements.

[0141] In 5G communication systems, network slicing has been introduced. Network slicing is a logical concept that reorganizes resources, allowing multiple isolated logical subnets with different characteristics to be virtually created on the same physical infrastructure to provide targeted services to users. Different logical subnets are identified and distinguished by single network slice selection assistance information (S-NSSAI). In actual network slicing deployment scenarios, due to network resource limitations, the number of users a single network slice can accommodate and the number of sessions it can support are limited.

[0142] According to current 5G standards, if network slicing requires admission control, this can be implemented through the NSACF (Network Access Control Function). For example, the NSACF can control the number of UEs accessing a network slice or the number of sessions established within that slice. Specifically, taking the NSACF's control over the number of UEs accessing a network slice as an example, the NSACF can configure the network slice's quota and store the number of users currently connected to that slice, controlling the number of UEs accessing the network slice during the UE registration or deregistration process. Taking the control of the number of UEs accessing a network slice during the registration process as an example, the UE can carry a requested NSSAI; the AMF determines whether the requested NSSAI contains a network slice that requires network slice admission control (NSAC). If the requested NSSAI contains a network slice that requires NSAC, the AMF can determine the target NSSAI, which is the set of all network slices that the UE requests to access and that require NSAC; the AMF interacts with the NSACF network element to trigger the NSACF to determine whether the current network slice quota allows the UE to access the network slice. If the current quota for a network slice included in the target NSSAI is still available, the UE can access that network slice. Simultaneously, the NSACF counts the number of users for network slices with available quotas and returns a "quota available" indication to the AMF. Network slices with "quota available" in the AMF are included in the allowed NSSAIs. Conversely, if the current quota for a network slice included in the target NSSAI is unavailable, the UE cannot access that network slice. The NSACF returns a "no quota available" indication to the AMF, and network slices with "no quota available" in the AMF are included in the rejected NSSAIs. Similarly, the number of sessions established by a network slice can also be controlled through the NSACF. Specifically, NSACF can configure network slice quotas and save the number of sessions currently established in the network slice. NSACF can control the number of sessions established in the network slice in the UE's PDU session management process. The specific process is similar to the process of controlling the number of UEs accessing the network slice, and will not be described in detail here.

[0143] It is important to note that the NSACF responsible for controlling the number of users accessing each network slice and the NSACF responsible for controlling the number of sessions established on each network slice can be the same or different.

[0144] for Figure 3 In the interoperability scenario shown, when a UE initiates a PDN connection establishment procedure, this PDN connection is associated with a core network element of a network slice, such as SMF+PGW-C. This can be understood as the UE using the network slice resources of SMF+PGW-C to establish a PDN connection. When a UE initiates a PDN connection release procedure, the resources of SMF+PGW-C associated with that PDN connection are released. When a UE residing on an EPC initiates a PDN connection establishment or release procedure, it simultaneously triggers control over the number of UEs accessing the network slice and the number of sessions established within the network slice. In this situation, how to control the number of users accessing the network slice and the number of sessions established within the network slice becomes a pressing issue.

[0145] To address the aforementioned issues, this application provides a network slice admission control method and apparatus, which can control the number of users accessing a network slice and the number of sessions established within a network slice, thereby facilitating network slice admission control.

[0146] Before describing the technical solution of this application, the terminology involved in this application will be described first.

[0147] The UE quota for network slices shown in this application can also be understood as: the number of UEs accessing the network slice, or the maximum number of UEs accessing the network slice, or the number of UEs allowed to access the network slice, or the number of UEs allowed to register in the network slice. The unavailability of the UE quota for network slices can also be understood as: the UE quota for network slices is exceeded, or the number of UEs accessing the network slice exceeds the quota, or the number of UEs already accessing the network slice exceeds the quota, or the number of UEs accessing the network slice exceeds the maximum value, or the number of UEs accessing the network slice has reached the maximum allowed number of UEs, or the number of UEs accessing the network slice is greater than or equal to a preset threshold, or the number of UEs already accessing the network slice is greater than or equal to a preset threshold. The availability of the UE quota for network slices can also be understood as: the number of UEs accessing the network slice does not exceed the maximum number, or the number of UEs accessing the network slice has not reached the maximum allowed number of UEs, or the number of UEs already accessing the network slice is less than or equal to a preset threshold, or the number of UEs already accessing the network slice is less than a preset threshold.

[0148] Similarly, the session quota for network slices shown in this application can also be understood as: the number of sessions already established in the network slice, or the maximum number of sessions already established in the network slice, or the number of sessions allowed to be established in the network slice, or the number of PDN connections allowed to be established in the network slice. The unavailability of the network slice session quota can be understood as: the network slice session quota is exceeded, or the number of sessions allowed to be established in the network slice exceeds the quota, or the number of sessions already established on the network slice exceeds the maximum value, or the number of sessions already established in the network slice has reached the maximum allowed number of sessions, or the number of sessions already established in the network slice is greater than or equal to a preset threshold, or the number of sessions already established in the network slice is greater than a preset threshold. The availability of the network slice session quota can also be understood as: the number of sessions established in the network slice does not exceed the maximum number, or the number of sessions established in the network slice does not reach the maximum allowed number of sessions, or the number of sessions established in the network slice is less than a preset threshold, or the number of sessions established in the network slice is less than or equal to a preset threshold.

[0149] In this application, failure to control or count the number of users accessing a network slice indicates that the number of users accessing the network slice has not changed, or the number of users accessing the network slice remains the same, or the update of the number of users accessing the network slice has failed. Similarly, failure to control or count the number of sessions established on a network slice indicates that the number of sessions established on the network slice has not changed, or the number of sessions established on the network slice remains the same, or the update of the number of sessions established on the network slice has failed.

[0150] It should be noted that, in this application, the number of users accessing a network slice can also be described as the number of users already connected to the network slice or the number of users corresponding to the network slice. The number of sessions established in a network slice can also be described as the number of sessions already established in the network slice or the number of sessions corresponding to the network slice. In this application, a session can be a PDU session or a PDN connection. The following describes a network slice admission control method provided by this application.

[0151] Figure 4 This is a schematic flowchart of the network slice admission control method provided in this application. Figure 4 The method shown can be executed by the first network element and the second network element, or by a module or unit within the first network element and the second network element; this application does not impose any restrictions. The technical solution of this application is described below using the first network element and the second network element as the executing entities.

[0152] exist Figure 4In the method shown, the network element that controls the number of users accessing the network slice (hereinafter referred to as the first network element, for example, NSACF_1, which controls the number of users accessing the network slice) and the network element that controls the number of sessions established on the network slice (hereinafter referred to as the third network element, for example, NSACF_2, which controls the number of sessions established on the network slice) are different.

[0153] Step 401: The second network element determines the network slice associated with the first session of the user equipment.

[0154] The second network element serves the first session.

[0155] The second network element serves the first session. This can be understood as associating the first session with the second network element when establishing the first session, or establishing the first session through the network slice resources supported by the second network element.

[0156] The network slice associated with the first session can be understood as the network slice on which the first session is established, or the network slice used to establish the first session.

[0157] One possible implementation is that the first session is a PDN connection, and the second network element is SMF+PGW-C. Specifically, SMF+PGW-C can determine the network slice associated with the PDN connection based on the access point name (APN) carried in the session creation request message received during the PDN connection establishment process.

[0158] Step 402: The second network element sends first information to the first network element. Correspondingly, the first network element receives the first information from the second network element.

[0159] The first network element supports controlling the number of users accessing the network slice. This control can also be described as the first network element supporting UE counting or having the capability to control the number of users accessing the network slice. The aforementioned first information is used to associate a first session of a user equipment (UE), or can be described as information related to a first session of the UE. As an example, the first information is used to identify the first session; for example, the first information may include at least one of an identifier for the first session or an identifier for a second network element. The identifier for the second network element can be its ID, and the identifier for the first session is used to identify the first session, such as a PDU session ID.

[0160] Optionally, the first network element can be NSACF, and the second network element can be SMF+PGW-C.

[0161] This application does not limit the timing of the second network element sending the first information.

[0162] In some implementations, the second network element can send first information to the first network element during the process of requesting an increase in the number of users accessing the network slice determined in step 401. For example, in the control process of the number of UEs and sessions triggered by the establishment of a PDN connection, the second network element can first interact with the first network element that supports controlling the number of users accessing the network slice, triggering the first network element to increase the number of users accessing the network slice, and sending first information to the first network element during the interaction with the first network element; if the number of users accessing the network slice is not exceeded, the second network element then interacts with the third network element that supports controlling the number of sessions established on the network slice, triggering the third network element to increase the number of sessions established on the network slice. In this example, if the second network element learns from the third network element that the session number control is successful, the second network element does not need to interact with the first network element again, which can reduce signaling overhead.

[0163] In other implementations, the second network element can send a second request message to the first network element when the number of sessions established on the network slice determined in step 401 does not exceed the maximum number of sessions allowed to be established on that network slice, and the second request message carries the first information. For example, in the control process of the number of UEs and sessions triggered by the establishment of a PDN connection, the second network element can first interact with the first network element that supports the control of the number of users accessing the network slice, triggering the first network element to increase the number of users accessing the network slice; if the number of users accessing the network slice does not exceed the limit, the second network element then interacts with the third network element that supports the control of the number of sessions established on the network slice, triggering the third network element to increase the number of sessions established on the network slice; if the second network element learns from the third network element that the session number control is successful, the second network element can send a second request message to the first network element, and the second request message carries the first information, so that the first network element can store the first information.

[0164] The aforementioned third network element can be an NSACF (Network Assisted Function), which differs from the first network element. The first network element is responsible for controlling the number of users accessing the network slice, while the third network element is responsible for controlling the number of sessions established on the network slice. The third network element supports controlling the number of sessions established on the network slice; this can also be described as the third network element supporting the counting of sessions established on the network slice, or the third network element possessing the capability to control the number of sessions established on the network slice.

[0165] In some other implementations, after receiving the first information, the first network element can also save the first information, the network slice, and the corresponding relationship of the user equipment.

[0166] Step 403: The second network element sends a first request message to the first network element. Correspondingly, the first network element receives the first request message from the second network element.

[0167] The first request message is used to instruct a reduction in the number of users already connected to the network slice.

[0168] Optionally, the first request message may be an Nnsacf_NumberOfUEsPerSliceAvailabilityCheckAnd Update request.

[0169] This application does not limit the timing of the second network element sending the first request message.

[0170] In some implementations, the second network element can send a first request message to the first network element during the release of the first session, so that the first network element can control the number of users already connected to the network slice. For example, after a PDN connection is successfully established, it is released at some point. During the control process of the number of UEs and sessions triggered by the release of the PDN connection, the second network element can interact with a third network element that supports controlling the number of sessions established on the network slice, triggering the third network element to reduce the number of sessions established on the network slice; the second network element can also send a first request message to the first network element that supports controlling the number of users connected to the network slice, triggering the first network element to reduce the number of sessions established on the network slice.

[0171] In other implementations, the second network element can send a first request message to the first network element when it learns from the third network element during the PDN connection establishment process that the session count control for the network slice has failed. This allows the first network element to control the number of users already connected to the network slice. For example, in the UE and session count control process triggered by the establishment of a PDN connection, the second network element can first interact with the first network element that supports controlling the number of users connected to the network slice, triggering the first network element to increase the number of users connected to the network slice. If the number of users connected to the network slice is not exceeded, the second network element then interacts with the third network element that supports controlling the number of sessions established on the network slice, triggering the third network element to increase the number of sessions established on the network slice. If the second network element learns from the third network element that the session count control has failed, the second network element can send a first request message to the first network element that supports controlling the number of users connected to the network slice, triggering the first network element to reduce the number of users established on the network slice.

[0172] Step 404: The first network element determines whether to reduce the number of users already connected to the network slice based on the first information.

[0173] In some implementations, the first network element determines whether the user equipment (UE) has established a session other than the first session on the network slice. For example, the first network element stores a correspondence between the UE, the network slice, and the sessions established by the UE on the network slice. The first network element can determine whether the UE has a session other than the first session on the network slice based on whether there is such a correspondence. If the UE has established a session other than the first session on the network slice, the first network element determines to maintain the number of users already connected to the network slice, that is, the first network element determines not to reduce the number of users already connected to the network slice. If the UE has only established the first session on the network slice, the first network element determines that the number of users already connected to the network slice can be reduced.

[0174] In other implementations, after receiving the first request message or determining whether to reduce the number of users already connected to the network slice, the first network element can also delete the first information. That is, regardless of whether the first network element determines to reduce or maintain the number of users already connected to the network slice, the first network element can delete the first information.

[0175] It should be noted that, for the first network element, whether the user equipment has established a certain session on the network slice can be understood as whether the first network element has stored relevant information about the session, such as the identifier of the session or the identifier of the session management network element serving the session.

[0176] Optionally, the first request message may also carry first information so that the first network element can determine the session that needs to be deleted.

[0177] It should be noted that, Figure 4 The first session in the network can also be a PDU session, and the second network element can also be an SMF, i.e. Figure 4 The method shown is also applicable to 5G communication systems.

[0178] In the above technical solution, the second network element sends session-related information to the first network element so that the first network element can store the correspondence between user equipment, network slices, and session-related information. When the first network element receives an instruction to reduce the number of users accessing the network slice, it can determine whether the number of users accessing the network slice can be reduced based on this correspondence. This enables network slice admission control.

[0179] Figure 5 This is a schematic flowchart of another network slice admission control method provided in this application. Figure 5The method shown can be executed by the second network element, the fourth network element, and the NRF, or by a module or unit within the second network element, the fourth network element, and the NRF; this application does not impose any restrictions. The technical solution of this application is described below using the second network element, the fourth network element, and the NRF as the executing entities.

[0180] exist Figure 5 In the method shown, the network element that controls the number of users accessing the network slice and the network element that controls the number of sessions established on the network slice are the same, hereinafter referred to as the fourth network element. In other words, the fourth network element can control both the number of users accessing the network slice and the number of sessions established on the network slice.

[0181] Step 501: The second network element determines the network slice associated with the first session of the user equipment.

[0182] The second network element serves the first session.

[0183] The second network element serves the first session. This can be understood as associating the first session with the second network element when establishing the first session, or establishing the first session through the network slice resources of the second network element.

[0184] The network slice associated with the first session can be understood as the network slice on which the first session is established, or the network slice used to establish the first session.

[0185] One possible implementation is that the first session is a PDN connection, and the second network element is SMF+PGW-C. Specifically, SMF+PGW-C can determine the network slice associated with the PDN connection based on the APN carried in the session creation request message received during the PDN connection establishment process.

[0186] Step 502: The second network element sends a third request message to the NRF. Correspondingly, the NRF receives the third request message from the second network element.

[0187] The third request message is used to request information from the fourth network element.

[0188] Optionally, the third request message includes the identifier of the network slice and second information. The second information indicates that the fourth network element requested by the second network element supports controlling the number of users accessing the network slice and controlling the number of sessions established on the network slice. The second information can also be referred to as network element capability information, indicating that the second network element requests a fourth network element with the capability to control the number of users accessing the network slice and the number of sessions established on the network slice.

[0189] In some implementations, the second network element can send a third request message during the establishment of a PDN connection.

[0190] One possible implementation is that the second network element can call the NRF service operation Nnrf_NFDiscoveryrequest.

[0191] Optionally, the second network element can be SMF+PGW-C, and the fourth network element can be NSACF.

[0192] Step 503: The NRF sends a third response message to the second network element. Correspondingly, the second network element receives the third response message from the NRF.

[0193] The third response message includes information about the fourth network element. For example, the third response message carries the address information of the fourth network element. The fourth network element supports controlling the number of users accessing the network slice and controlling the number of sessions established on the network slice.

[0194] One possible implementation is that NRF can send an Nnrf_NFDiscovery response to the second network element.

[0195] In step 504, the second network element sends a fourth request message to the fourth network element. Correspondingly, the fourth network element receives the fourth request message from the second network element.

[0196] The fourth request message is used to request the fourth network element to control the number of users accessing the network slice and to control the number of sessions established by the network slice. The fourth network element can be determined based on the third response message.

[0197] In some implementations, the fourth request message includes the user equipment's identifier, first information, third information, fourth information, and the network slice's identifier. The first information is used to associate the user equipment's first session; a detailed description of the first information can be found in step 402 and will not be repeated here. When the user equipment requests to establish a first session, the third information indicates an increase in the number of users already connected to the network slice, and the fourth information indicates an increase in the number of sessions already established in the network slice. When the user equipment requests to release a first session, the third information indicates a decrease in the number of users already connected to the network slice, and the fourth information indicates a decrease in the number of sessions already established in the network slice.

[0198] One possible implementation is that the second network element sends an Nnsacf_NumberOfUEsPerSliceAvailabilityCheckAndUpdate request to the fourth network element, or the second network element sends an Nnsacf_NumberOfPDUsPerSliceAvailabilityCheckAndUpdate request to the fourth network element.

[0199] Step 505: The fourth network element performs admission control on the network slice according to the fourth request message.

[0200] In some implementations, the fourth network element performs admission control on network slices, including admission control of the number of users and the number of sessions. This can also be described as counting the number of UEs and sessions, ensuring that the total number of UEs currently connected to the network slice does not exceed the maximum number of terminal devices allowed to access the network slice, and that the total number of sessions currently established in the network slice does not exceed the maximum number of sessions allowed to be established in the network slice. This application does not restrict the order in which the fourth network element performs user counting and session counting. The fourth network element can store the number of users currently connected to the network slice, or store a list of UE identifiers currently connected to the network slice, where the identifiers identify the UEs currently connected to the network slice. The fourth network element can also store the number of sessions currently established in the network slice. Furthermore, the fourth network element can configure the maximum number of users allowed to access the network slice and the maximum number of sessions allowed to be established in the network slice; that is, the fourth network element can configure the maximum number of users allowed to access the network slice and the maximum number of sessions allowed to be established in the network slice.

[0201] When a user equipment (UE) requests to establish a first session, the third information is used to indicate the increase in the number of users already connected to the network slice, and the fourth information is used to indicate the increase in the number of sessions already established on the network slice. The fourth network element determines whether the number of users connected to the network slice exceeds the maximum number of users allowed to access the network slice, and whether the number of sessions established on the network slice exceeds the maximum number of sessions allowed to be established on the network slice. If the fourth network element determines that the number of users corresponding to the network slice does not exceed the maximum number of users allowed to access the network slice, and the UE's ID is not stored in the list of UE identifiers already connected to the network slice, then the fourth network element can increase the number of users corresponding to the network slice according to the third information and add the UE's ID to the list of UE identifiers already connected to the network slice, thereby saving the correspondence between the UE's ID and the network slice. Simultaneously, if the fourth network element determines that the number of sessions corresponding to the network slice does not exceed the maximum number of sessions allowed to be established on the network slice, the fourth network element can increase the number of sessions corresponding to the network slice according to the fourth information and save the correspondence between the first information and the network slice. If the number of users corresponding to the network slice exceeds the maximum number of users allowed to access the network slice and / or the number of sessions exceeds the maximum number of sessions allowed to be established by the network slice, then the fourth network element may not change the number of users corresponding to the network slice or the number of sessions corresponding to the network slice.

[0202] When a user equipment (UE) requests to release the first session, the third information is used to indicate a reduction in the number of users already connected to the network slice, and the fourth information is used to indicate a reduction in the number of sessions already established on the network slice. The fourth network element reduces the number of sessions corresponding to the network slice based on the fourth information and deletes the first information from the context information. The fourth network element determines whether the UE has established any sessions on the network slice other than the first session. For example, the first network element stores the correspondence between the UE, the network slice, and the sessions established by the UE on the network slice. The first network element can determine whether the UE has any sessions on the network slice other than the first session based on whether there are any sessions other than the first session in this correspondence. If the UE has established any sessions on the network slice other than the first session, the first network element determines to maintain the number of users already connected to the network slice, i.e., the first network element determines not to reduce the number of users already connected to the network slice. If the UE has only established the first session on the network slice, the first network element determines that the number of users already connected to the network slice can be reduced.

[0203] Step 506: The fourth network element sends a fourth response message to the second network element. Correspondingly, the second network element receives the fourth response message from the fourth network element.

[0204] The fourth response message indicates the result of admission control for the network slice. This result can include: admission control for the network slice was successful or failed. If the second network element determines that the number of users accessing the network slice does not exceed the maximum number of users allowed to access the network slice, and the number of sessions established on the network slice does not exceed the maximum number of sessions allowed to be established on the network slice, then admission control for the network slice is successful. Based on the above description, it can be understood that if admission control for the network slice is successful, it means that both the counting of the number of UEs and the counting of the number of sessions were successful. If the second network element determines that the number of users accessing the network slice exceeds the maximum number of users allowed to access the network slice, but the number of sessions established on the network slice does not exceed the maximum number of sessions allowed to be established on the network slice, then the network slice admission control fails. Based on the above description, it can be understood that if admission control for a network slice fails, it indicates that the count of the number of UEs and / or the count of the number of sessions has failed. In this case, the fourth response message can also carry a failure reason value. If the user equipment requests to establish the first session, the failure reason value can be whether the number of users accessing the network slice exceeds the maximum number of users allowed to access the network slice and / or whether the number of sessions established on the network slice exceeds the maximum number of sessions allowed to be established on the network slice. If the user equipment requests to release the first session, the failure reason value can be that the user equipment still has other sessions on the network slice.

[0205] same, Figure 5 The first session in the network can also be a PDU session, and the second network element can also be an SMF, i.e. Figure 5 The method shown is also applicable to 5G communication systems.

[0206] In the above technical solution, the process of the second network element discovering the fourth network element is first enhanced. Specifically, the second network element requests the NRF to select a fourth network element that simultaneously supports controlling the number of UEs accessing the network slice and controlling the number of sessions established on the network slice. Secondly, when determining the number of users and sessions corresponding to the network slice, the fourth network element also determines whether the user equipment has already accessed the network slice or whether all of the user equipment's sessions should be released. This enables network slice admission control in interoperability scenarios.

[0207] The technical solution of this application will be described in detail below with specific examples.

[0208] Example 1

[0209] In Example 1, the UE initiates the establishment process of multiple PDN connections, and the multiple PDN connections are associated with the same network slice. The NSACF responsible for the quota management of the number of UEs in the network slice is the same NSACF responsible for the quota management of the number of sessions in the network slice. Figure 6 Take the establishment of two PDN connections by the UE as an example.

[0210] Figure 6 This is an example of the network slice admission control method provided in this application. Figure 6 SMF+PGW-C_1 and SMF+PGW-C_2 in the above text can correspond to the above text. Figure 5 The second network element, NSACF, can correspond to the one mentioned above. Figure 5 The fourth network element in the system.

[0211] Step 601: The UE initiates the PDN connection establishment process.

[0212] One possible implementation is that the UE sends a PDN connectivity request message to the MME, which may carry the APN. Upon receiving the PDN connectivity request message, the MME selects the serving gateway (SGW) and the SMF+PGW-C network element based on the APN carried in the message and the UE's location. The MME then sends a create session request message to the SGW, which in turn sends a create session request message to the selected SMF+PGW-C. For ease of description, this PDN connection will be referred to as PDN connection_1, and the selected SMF+PGW-C will be referred to as SMF+PGW-C_1.

[0213] Step 602, SMF+PGW-C_1 determines the network slice associated with the PDN connection.

[0214] One possible implementation is that SMF+PGW-C_1 determines the network slice associated with the PDN connection based on the APN carried in the session creation request message.

[0215] Step 603: SMF+PGW-C_1 determines whether the network slice needs to execute the NSAC process based on the configuration information.

[0216] One possible implementation is that the SMF+PGW-C_1 stores the configuration information of the network slices that need to perform NSAC. After the SMF+PGW-C_1 determines the network slice associated with the PDN connection, it determines whether the network slice needs to perform the NSAC procedure based on the configuration information.

[0217] If SMF+PGW-C_1 determines that the network slice requires the NSAC procedure, then proceed to steps 604-608. If SMF+PGW-C_1 determines that the network slice does not require the NSAC procedure, then skip steps 604-608 and proceed directly to step 609.

[0218] Step 604, SMF+PGW-C_1 sends a third request message_1 to NRF.

[0219] The third request message_1 is used to request an NSACF that serves the network slice associated with PDN connection_1, supports control over the number of UEs accessing the network slice, and supports control over the number of sessions established on the network slice. As an example, the third request message_1 may carry S-NSSAI and NSACF service capability indication information to identify the network slice. The NSACF service capability indication information indicates that the NSACF requested by SMF+PGW-C_1 supports control over the number of UEs accessing the network slice and supports control over the number of sessions established on the control network slice. Figure 5 The second piece of information described in the text.

[0220] It should be noted that NSACF supports controlling the number of UEs accessing a network slice. In other words, NSACF has the capability to control the number of UEs accessing a network slice. The same description applies below. Similarly, NSACF supports controlling the number of sessions established on a network slice.

[0221] One possible implementation is that SMF+PGW-C_1 can call the NRF service operation Nnrf_NFDiscoveryrequest.

[0222] Step 605: NRF sends a third response message _1 to SMF+PGW-C_1 based on the third request message _1.

[0223] The third response message_1 carries information about the NSACF. This information may include the NSACF's address. This NSACF serves the network slice identified by the S-NSSAI carried in the third request message_1, and it simultaneously supports control over the number of UEs accessing the network slice identified by the S-NSSAI and the number of sessions established on the network slice identified by the S-NSSAI.

[0224] One possible implementation is that the NRF returns an Nnrf_NFDiscovery response to the SMF+PGW-C_1, carrying NSACF information, such as the NSACF's address information.

[0225] Optionally, SMF+PGW-C_1 stores the NSACF information returned by NRF in the context.

[0226] Step 606: SMF+PGW-C_1 determines the NSACF based on the third response message_1 and sends the fourth request message_1 to the NSACF.

[0227] The fourth request message_1 may carry the UE ID, update flag_1, S-NSSAI, update flag_2, and session_1 related information. The UE ID can be determined by SMF+PGW-C_1 based on the session creation request message. For example, if the session creation request message carries the UE ID, this UE ID can be a permanent identifier for the UE, such as the International Mobile Subscriber Identity (IMSI). Update flag_1 indicates an increase in the number of UEs corresponding to the network slice identified by S-NSSAI, for example, incrementing the UE count by 1. Update flag_2 indicates an increase in the number of sessions corresponding to the network slice identified by S-NSSAI, for example, incrementing the session count by 1. Information related to session_1 may include the identifier of SMF+PGW-C_1 and / or the identifier of session_1. The identifier of SMF+PGW-C_1 may be the ID of SMF+PGW-C_1. The identifier of session_1 is used to identify the session_1, such as PDU session ID_1. The PDU session ID_1 may be included in the session creation request message.

[0228] One possible implementation is that SMF+PGW-C_1 sends an Nnsacf_NumberOfPDUsPerSliceAvailabilityCheckAndUpdate request to NSACF, or SMF+PGW-C_1 sends an Nnsacf_NumberOfUEsPerSliceAvailabilityCheckAndUpdate request to NSACF; this application does not limit the specific implementation.

[0229] Step 607: NSACF performs admission control on the network slice according to the fourth request message _1.

[0230] One possible implementation is that NSACF performs admission control on network slices, including admission control for the number of UEs and admission control for the number of sessions. This can also be referred to as UE counting and session counting, ensuring that the total number of UEs currently connected to the network slice does not exceed the maximum number of terminal devices allowed to access the network slice, and that the total number of sessions currently established in the network slice does not exceed the maximum number of sessions allowed to be established in the network slice. NSACF can store the number of UEs currently connected to the network slice, or store a list of UE identifiers currently connected to the network slice, where identifiers identify the UEs currently connected to the network slice. NSACF can also store the number of sessions currently established in the network slice. Furthermore, NSACF can configure the maximum number of UEs allowed to access the network slice and the maximum number of sessions allowed to be established in the network slice; that is, NSACF can configure the maximum number of users allowed to access the network slice and the maximum number of sessions allowed to be established in the network slice.

[0231] For example, the NSACF determines whether the quota for the number of UEs corresponding to the network slice identified by S-NSSAI is available (i.e., whether the number of UEs currently accessing the network slice identified by S-NSSAI exceeds the maximum number), and whether the quota for the number of sessions corresponding to the network slice identified by S-NSSAI is available (i.e., whether the number of sessions currently established by the network slice identified by S-NSSAI exceeds the maximum number). If the NSACF determines that the quota for the number of UEs corresponding to the network slice identified by S-NSSAI is available, and the UE ID is not stored in the list of UE IDs already accessed by the network slice identified by S-NSSAI, the NSACF increments the number of UEs corresponding to the network slice according to the update flag _1 (e.g., increments the number of UEs accessing the network slice identified by S-NSSAI by 1), and adds the UE ID to the list of UE IDs already accessed by the network slice, thereby saving the correspondence between the UE ID and S-NSSAI. The NSACF also determines whether the session quota for the network slice identified by S-NSSAI is available. The NSACF increments the session count corresponding to that network slice based on update flag _2 (e.g., incrementing the number of sessions established within the network slice identified by S-NSSAI by 1), and saves the information related to session _1 and the correspondence with S-NSSAI. If the UE quota and / or session quota for the network slice identified by S-NSSAI are unavailable, the NSACF may not change the number of UEs or sessions corresponding to that network slice.

[0232] It should be noted that this application does not restrict the order in which the NSACF performs the UE count and the session count. For example, the UE count can be performed first, followed by the session count. In this case, if the NSACF determines that the session quota is unavailable after determining that the UE quota corresponding to the network slice identified by S-NSSAI is available and incrementing the UE count, the NSACF will update the UE count after determining that the session quota is unavailable, that is, the NSACF will decrement the UE count and remove the UE ID from the list of terminal devices already connected to that network slice. Alternatively, the session count can be performed first, followed by the UE count. In this case, if the NSACF determines that the UE quota is unavailable after determining that the session quota corresponding to the network slice identified by S-NSSAI is available and incrementing the session count, the NSACF will update the session count after determining that the UE quota is unavailable, that is, the NSACF will decrement the session count. For example, the count of UEs and the count of sessions can be performed simultaneously. In this case, NSACF can combine the judgment results of the UE quota and the judgment results of the session quota to update the UE count and the session count in a unified manner.

[0233] because Figure 6Taking the establishment of two PDN connections as an example, this is the establishment of the first PDN connection. Therefore, NSACF will increase the number of UEs corresponding to the network slice (for example, the number of UEs accessing the network slice identified by S-NSSAI is increased by 1) and increase the number of sessions corresponding to the network slice (for example, the number of sessions established within the network slice identified by S-NSSAI is increased by 1), and save the correspondence between UE ID, S-NSSAI and session_1 related information.

[0234] Step 608, NSACF sends the fourth response message _1 to SMF+PGW-C_1.

[0235] The fourth response message_1 is used to indicate the result of admission control for the network slice. This result can include: admission control for the network slice was successful or failed. If admission control for the network slice is successful, it means that both the count of the number of UEs and the count of the number of sessions were successful. If admission control for the network slice fails, it means that the count of the number of UEs and / or the count of the number of sessions failed. The fourth response message_1 can also carry a failure reason value, which can be used to indicate that the number of UEs already connected to the network slice has reached its maximum value and / or that the number of sessions already established in the network slice has reached its maximum value. In this example, the fourth response message_1 can indicate that admission control for the network slice was successful.

[0236] One possible implementation is that NSACF sends an Nnsacf_NumberOfPDUsPerSliceAvailabilityCheckAndUpdate response to SMF+PGW-C_1, or NSACF sends an Nnsacf_NumberOfUEsPerSliceAvailabilityCheckAndUpdate response to SMF+PGW-C_1. This application does not limit the implementation. NSACF carries the result of performing admission control on the network slice in the message it sends.

[0237] Step 609: Execute the remaining procedures for establishing the PDN connection.

[0238] At this point, the establishment of PDN connection_1 is complete, and NSACF has saved the correspondence between UE ID, S-NSSAI, and session_1 related information.

[0239] In step 610, the UE initiates the PDN connection establishment process again.

[0240] The implementation method of step 610 is the same as that of step 601, and can be referred to the description of step 601, which will not be repeated here. For ease of description, the PDN connection will be referred to as PDN connection_2 in the following text, and the selected SMF+PGW-C will be referred to as SMF+PGW-C_2.

[0241] Step 611, SMF+PGW-C_2 determines the network slice associated with the PDN connection.

[0242] One possible implementation is that SMF+PGW-C_2 determines the network slice associated with the PDN connection based on the APN carried in the session creation request message.

[0243] The network slice determined in step 611 is the same as the network slice determined in step 603.

[0244] Step 612: SMF+PGW-C_2 determines whether the network slice needs to execute the NSAC process based on the configuration information.

[0245] One possible implementation is that the SMF+PGW-C_2 stores the configuration information of the network slices that need to perform NSAC. After the SMF+PGW-C_2 determines the network slice associated with the PDN connection, it determines whether the network slice needs to perform the NSAC procedure based on the configuration information.

[0246] If SMF+PGW-C_2 determines that the network slice requires the NSAC procedure, then proceed to steps 613-617. If SMF+PGW-C_2 determines that the network slice does not require the NSAC procedure, then skip steps 613-617 and proceed directly to step 618.

[0247] Step 613, SMF+PGW-C_2 sends a third request message_2 to NRF.

[0248] The third request message_2 is used to request an NSACF that serves the network slice associated with PDN connection_2 and supports control over the number of UEs accessing the network slice and the number of sessions established on the network slice. As an example, the third request message_2 may carry S-NSSAI and NSACF service capability indication information to identify the network slice. The NSACF service capability indication information indicates that the NSACF requested by SMF+PGW-C_2 simultaneously supports control over the number of UEs accessing the network slice identified by the S-NSSAI and the number of sessions established on the network slice identified by the S-NSSAI.

[0249] One possible implementation is that SMF+PGW-C_2 can call the NRF service operation Nnrf_NFDiscoveryrequest.

[0250] Step 614: NRF sends a third response message _2 to SMF+PGW-C_2 based on the third request message _2.

[0251] The third response message _2 carries information about the NSACF. This information may include the NSACF's address. This NSACF serves the network slice identified by the S-NSSAI carried in the third request message _2, and it simultaneously supports control over the number of UEs accessing the network slice identified by the S-NSSAI and the number of sessions established on the network slice identified by the S-NSSAI. The NSACF in step 614 is the same as the NSACF in step 605.

[0252] One possible implementation is that the NRF returns an Nnrf_NFDiscovery response to the SMF+PGW-C_2, carrying NSACF information, such as the NSACF's address information.

[0253] Optionally, SMF+PGW-C_2 stores the NSACF information returned by NRF in the context.

[0254] Step 615: SMF+PGW-C_2 determines the NSACF based on the third response message_2 and sends the fourth request message_2 to the NSACF.

[0255] The fourth request message_2 may carry the UE ID, update flag_1, S-NSSAI, update flag_2, and session_2 related information. The UE ID may be determined by SMF+PGW-C_2 based on the session creation request message. For example, if the session creation request message carries the UE ID, this UE ID may be the UE's IMSI. Update flag_1 indicates an increase in the number of UEs corresponding to the network slice identified by S-NSSAI, for example, incrementing the UE count by 1. Update flag_2 indicates an increase in the number of sessions corresponding to the network slice identified by S-NSSAI, for example, incrementing the session count by 1. Session_2 related information may include the identifier of SMF+PGW-C_2 and / or the identifier of session_2. The identifier of SMF+PGW-C_2 may be the ID of SMF+PGW-C_2, and the identifier of session_2 is used to identify the session_2, such as PDU session ID_2, which may be included in the session creation request message.

[0256] One possible implementation is that SMF+PGW-C_2 sends an Nnsacf_NumberOfPDUsPerSliceAvailabilityCheckAndUpdate request to NSACF, or SMF+PGW-C_2 sends an Nnsacf_NumberOfUEsPerSliceAvailabilityCheckAndUpdate request to NSACF; this application does not limit the specific implementation.

[0257] Step 616: NSACF performs admission control on the network slice according to the fourth request message _2.

[0258] One possible implementation is that NSACF performs admission control on network slices, including admission control of the number of UEs and admission control of the number of sessions on network slices, which can also be referred to as counting the number of UEs and counting the number of sessions.

[0259] Specifically, NSACF determines whether the quota for the number of UEs corresponding to the network slice identified by S-NSSAI is available (i.e., whether the number of UEs currently accessing the network slice identified by S-NSSAI exceeds the maximum number), and whether the quota for the number of sessions corresponding to the network slice identified by S-NSSAI is available (i.e., whether the number of sessions currently established by the network slice identified by S-NSSAI exceeds the maximum number). Based on the mapping between UE IDs and S-NSSAIs stored in the context information (i.e., the mapping between UE IDs and S-NSSAIs stored in step 607), the NSACF determines that the UE ID has been stored in the list of UE identifiers already accessed by the network slice identified by the S-NSSAI. This indicates that the UE has already accessed the network slice identified by the S-NSSAI. In this case, the NSACF does not need to count the number of UEs corresponding to the network slice, meaning the number of UEs in the network slice remains unchanged. Simultaneously, the NSACF determines that the session quota for the network slice identified by the S-NSSAI is available. The NSACF increments the number of sessions corresponding to the network slice according to update flag_2 (e.g., incrementing the number of sessions established within the network slice identified by the S-NSSAI by 1) and saves the session_2-related information and the mapping between the S-NSSAI and the UE IDs. If the quota for the number of UEs and / or the quota for the number of sessions corresponding to the network slice identified by the S-NSSAI is unavailable, the NSACF may not change the number of UEs or the number of sessions corresponding to the network slice.

[0260] Similarly, this application does not restrict the order in which NSACF counts the number of UEs and the number of sessions executed. For details, please refer to the above text, which will not be repeated here.

[0261] because Figure 6 Taking the establishment of two PDN connections as an example, since this is the establishment of the second PDN connection, NSACF will keep the number of UEs corresponding to the network slice unchanged, increase the number of sessions corresponding to the network slice, and continue to save the UE ID, session_2 related information and the correspondence of S-NSSAI.

[0262] Step 617, NSACF sends the fourth response message _2 to SMF+PGW-C_2.

[0263] The fourth response message_2 is used to indicate the result of admission control performed on the network slice. This result can include: admission control performed on the network slice was successful or failed. If admission control was successful, it means both the count of the number of UEs and the count of the number of sessions were successful. If admission control failed, it means the count of the number of UEs and / or the count of the number of sessions failed. In this case, the fourth response message_2 can also carry a failure reason value, for example, indicating that the number of UEs already connected to the network slice has reached its maximum value and / or that the number of sessions already established on the network slice has reached its maximum value. In this example, the fourth response message_2 can indicate that admission control performed on the network slice was successful.

[0264] One possible implementation is that NSACF sends an Nnsacf_NumberOfPDUsPerSliceAvailabilityCheckAndUpdate response to SMF+PGW-C_2, or NSACF sends an Nnsacf_NumberOfUEsPerSliceAvailabilityCheckAndUpdate response to SMF+PGW-C_2. This application does not limit the implementation. NSACF carries the result of performing admission control on the network slice in the message it sends.

[0265] Step 618: Perform the remaining procedures for establishing the PDN connection.

[0266] This completes the establishment of PDN connection_1 and PDN connection_2. The NSACF stores the correspondence between UE ID, S-NSSAI, session_1 related information and session_2 related information.

[0267] As discussed above, in Example 1, the process for determining the number of UEs and sessions triggered by establishing a PDN connection has been enhanced. Specifically, the SMF+PGW-C process for discovering the NSACF has been improved. Specifically, the SMF+PGW-C requests the NRF to select an NSACF that simultaneously supports controlling the number of UEs accessing the network slice and controlling the number of sessions established on the network slice. Secondly, when determining the number of UEs and sessions corresponding to a network slice, the NSACF also checks whether the UE has already accessed the network slice. If the UE has already accessed the network slice, the UE count does not need to be increased. This enables network slice admission control in interoperability scenarios.

[0268] Example 2

[0269] In Example 2, the UE initiates the release process of multiple PDN connections respectively, and the multiple PDN connections are associated with the same network slice. The NSACF responsible for the quota management of the number of UEs in the network slice is the same NSACF responsible for the quota management of the number of sessions in the network slice. Figure 7 Take the example of a UE establishing two PDN connections. Assume that, according to Example 1, the UE has already established two PDN connections (PDN connection_1 and PDN connection_2) for the same network slice. At a certain moment, the UE initiates a PDN connection release procedure to the network.

[0270] Figure 7 This is another example of the network slice admission control method provided in this application. Figure 7 SMF+PGW-C_1 and SMF+PGW-C_2 in the above text can correspond to the above text. Figure 5 The second network element, NSACF, can correspond to the one mentioned above. Figure 5 The fourth network element in the system.

[0271] Step 701: The UE initiates the release procedure for PDN connection_1.

[0272] One possible implementation is that the UE sends a PDN disconnection request to the MME; after receiving the message, the MME determines that the UE wants to release the PDN connection, and the MME sends a delete session request to the SGW serving the PDN connection. The SGW then sends a delete session request to the SMF+PGW-C_1 serving the PDN connection.

[0273] Step 702, SMF+PGW-C_1 sends the fourth request message_3 to NSACF.

[0274] The fourth request message_3 may carry the UE ID, update flag_1, S-NSSAI, update flag_2, and information related to session_1. The UE ID may be determined by SMF+PGW-C_1 based on the session deletion request message; for example, the UE ID may be a permanent identifier for the UE, such as the IMSI. Update flag_1 indicates a reduction in the number of UEs corresponding to the network slice identified by S-NSSAI, for example, decrementing the number of UEs by 1. Update flag_2 indicates a reduction in the number of sessions corresponding to the network slice identified by S-NSSAI, for example, decrementing the number of sessions by 1. Information related to session_1 may include the identifier of SMF+PGW-C_1 and / or the identifier of session_1. The identifier of SMF+PGW-C_1 may be the ID of SMF+PGW-C_1, and the identifier of session_1 is used to identify session_1, such as PDU session ID_1, which may be included in the session creation request message.

[0275] One possible implementation is that if SMF+PGW-C_1 stores NSACF information in the context, then SMF+PGW-C_1 can directly determine the NSACF based on that NSACF information.

[0276] As an alternative implementation, if SMF+PGW-C_1 does not store NSACF information in the context, then SMF+PGW-C_1 can request the NRF to discover the NSACF. This method can be referenced in steps 604 and 605 above.

[0277] One possible implementation is that SMF+PGW-C_1 sends an Nnsacf_NumberOfPDUsPerSliceAvailabilityCheckAndUpdate request to NSACF, or SMF+PGW-C_1 sends an Nnsacf_NumberOfUEsPerSliceAvailabilityCheckAndUpdate request to NSACF; this application does not limit the specific implementation.

[0278] Step 703: NSACF performs admission control on the network slice according to the fourth request message _3.

[0279] One possible implementation is that NSACF performs admission control on network slices, including admission control on the number of UEs and admission control on the number of sessions. This can also be referred to as counting the number of UEs and counting the number of sessions. This application does not restrict the order in which NSACF performs the counting of the number of UEs and the counting of the number of sessions.

[0280] One possible implementation is that the NSACF first performs a session count. Based on the update flag _2, the NSACF reduces the number of sessions corresponding to the network slice identified by S-NSSAI (e.g., the NSACF will decrement the number of sessions established within the network slice identified by S-NSSAI by 1), and deletes the SMF+PGW-C ID_1 identifier from the context information. Since NSACF_1 stores both session_1-related information and session_2-related information for this UE ID, and the UE is currently only releasing the PDN connection_1 corresponding to the session_1-related information, the NSACF determines that the UE still has other sessions. Therefore, there is no need to reduce the number of UEs accessing the network slice identified by S-NSSAI. The NSACF deletes the session_1-related information and continues to maintain the correspondence between the UE ID, session_2-related information, and S-NSSAI. That is, the UE ID is continued to be stored in the list of UE identifiers already accessing the network slice identified by S-NSSAI.

[0281] Step 704, NSACF sends the fourth response message _3 to SMF+PGW-C_1.

[0282] The fourth response message_3 is used to indicate the result of admission control performed on the network slice. This result can include: admission control performed on the network slice was successful or failed. If admission control performed on the network slice was successful, it means that both the count of the number of UEs and the count of the number of sessions were successful. If admission control performed on the network slice failed, it means that the count of the number of UEs and / or the count of the number of sessions failed. In this case, the fourth response message_3 can also carry a failure reason value, which could be that the UE has other sessions on the network slice. In step 704, the fourth response message_3 can indicate that admission control performed on the network slice failed, and the fourth response message_3 can also carry a failure reason value, such as the UE having other sessions on the network slice.

[0283] One possible implementation is that NSACF sends an Nnsacf_NumberOfPDUsPerSliceAvailabilityCheckAndUpdate response to SMF+PGW-C_1, or NSACF sends an Nnsacf_NumberOfUEsPerSliceAvailabilityCheckAndUpdate response to SMF+PGW-C_1. This application does not limit the implementation. NSACF carries the result of performing admission control on the network slice in the message it sends.

[0284] Step 705: Perform the remaining procedures for releasing the PDN connection.

[0285] At this point, the release of PDN connection _1 is complete.

[0286] In step 706, the UE initiates the release process of PDN connection_2 again.

[0287] The implementation method of step 706 is the same as that of step 701. Please refer to the description of step 701, and it will not be repeated here.

[0288] Step 707: SMF+PGW-C_2 sends the fourth request message_4 to NSACF.

[0289] The fourth request message _4 may carry the UE ID, update flag _1, S-NSSAI, update flag _2, and information related to session _2. The UE ID may be determined by SMF+PGW-C_2 based on the session deletion request message; for example, this UE ID may be the UE's IMSI. Update flag _1 indicates a reduction in the number of UEs corresponding to the network slice identified by S-NSSAI, for example, decrementing the number of UEs by 1. Update flag _2 indicates a reduction in the number of sessions corresponding to the network slice identified by S-NSSAI, for example, decrementing the number of sessions by 1. Information related to session _2 may include the identifier of SMF+PGW-C_2 and / or the identifier of session _2. The identifier of SMF+PGW-C_2 may be the ID of SMF+PGW-C_2, and the identifier of session _2 is used to identify the session _2, such as PDU session ID_2, which may be included in the session creation request message.

[0290] One possible implementation is that if SMF+PGW-C_2 stores NSACF information in the context, then SMF+PGW-C_2 can directly determine the NSACF based on that NSACF information.

[0291] As an alternative implementation, if SMF+PGW-C_2 does not store NSACF information in the context, then SMF+PGW-C_2 can request the NRF to discover NSACF. This method can be referenced in steps 613 and 614 above.

[0292] One possible implementation is that SMF+PGW-C_2 sends an Nnsacf_NumberOfPDUsPerSliceAvailabilityCheckAndUpdate request to NSACF, or SMF+PGW-C_2 sends an Nnsacf_NumberOfUEsPerSliceAvailabilityCheckAndUpdate request to NSACF; this application does not limit the specific implementation.

[0293] Step 708: NSACF performs admission control on the network slice according to the fourth request message _4.

[0294] One possible implementation is that NSACF performs admission control on network slices, including admission control on the number of UEs and admission control on the number of sessions. This can also be referred to as counting the number of UEs and counting the number of sessions. This application does not restrict the order in which NSACF performs the counting of the number of UEs and the counting of the number of sessions.

[0295] One possible implementation is that the NSACF first performs a session count. The NSACF then reduces the number of sessions corresponding to the network slice identified by S-NSSAI based on update flag _2 (e.g., the NSACF decrements the number of sessions established within the network slice identified by S-NSSAI by 1), and deletes session_2-related information from the context information. Since the context information only stores session_2-related information for this UE ID, after deleting the session_2-related information, there are no other established sessions for this UE. Therefore, the NSACF can count the UEs based on update flag _1 (i.e., the NSACF reduces the number of UEs accessing the network slice identified by S-NSSAI) and delete the UE ID from the context information. In other words, the NSACF removes the UE ID from the list of UEs already accessing the network slice identified by S-NSSAI.

[0296] Step 709, NSACF sends the fourth response message _4 to SMF+PGW-C_2.

[0297] The fourth response message_4 is used to indicate the result of admission control for the network slice. This result can include: admission control for the network slice was successful or failed. If admission control for the network slice was successful, it means that both the count of the number of UEs and the count of the number of sessions were successful. If admission control for the network slice failed, it means that the count of the number of UEs and / or the count of the number of sessions failed, and the fourth response message_4 can also carry a failure reason value. In step 709, the fourth response message_4 can indicate that admission control for the network slice was successful.

[0298] One possible implementation is that NSACF sends an Nnsacf_NumberOfPDUsPerSliceAvailabilityCheckAndUpdate response to SMF+PGW-C_2, or NSACF sends an Nnsacf_NumberOfUEsPerSliceAvailabilityCheckAndUpdate response to SMF+PGW-C_1. This application does not limit the implementation. NSACF carries the result of performing admission control on the network slice in the message it sends.

[0299] Step 710: Perform the remaining procedures for releasing the PDN connection.

[0300] At this point, the release of PDN connection_1 and PDN connection_2 has been completed.

[0301] As discussed above, in Example 2, regarding the process of determining the number of UEs and sessions triggered by the release of PDN connections, the NSACF, when determining the number of UEs and sessions corresponding to a network slice, also checks whether all PDN connections of that UE should be released. If the UE has no established sessions, the NSACF reduces the number of UEs accessing the network slice identified by S-NSSAI and deletes that UE ID from the context information. This enables network slice admission control in interoperability scenarios.

[0302] Example 3

[0303] In Example 3, the UE initiates the establishment process for multiple PDN connections, and the multiple PDN connections are associated with the same network slice. The NSACF responsible for the quota management of the number of UEs in the network slice is different from the NSACF responsible for the quota management of the number of sessions in the network slice. Figure 8 and Figure 9 Taking the establishment of two PDN connections by the UE as an example, where, Figure 8 The process of establishing the first PDN connection (hereinafter referred to as PDN connection_1) is shown. Figure 9 The process of establishing the second PDN connection (hereinafter referred to as PDN connection_2) is shown.

[0304] Figure 8 This is another example of the network slice admission control method provided in this application. Figure 8 SMF+PGW-C_1 in the above text can correspond to the above. Figure 4 The second network element, NSACF_1, can correspond to the one mentioned above. Figure 4 The first network element in the above, NSACF_2, can correspond to the third network element involved in steps 402-403 above.

[0305] Step 801: The UE initiates the PDN connection establishment process.

[0306] Step 802, SMF+PGW-C_1 determines the network slice associated with the PDN connection.

[0307] Step 803: SMF+PGW-C_1 determines whether the network slice needs to execute the NSAC process based on the configuration information.

[0308] The implementation of steps 801-803 is the same as that of steps 601-603, and can be found in the description of steps 601-603, which will not be repeated here. For ease of description, the selected SMF+PGW-C will be referred to as SMF+PGW-C_1 below.

[0309] If SMF+PGW-C_1 determines that the network slice requires the NSAC procedure, then proceed to steps 804-816. If SMF+PGW-C_1 determines that the network slice does not require the NSAC procedure, then skip steps 804-816 and proceed directly to step 817.

[0310] Step 804: SMF+PGW-C_1 sends the seventh request message_1 to NRF.

[0311] The seventh request message_1 is used to request an NSACF that serves the network slice associated with PDN connection_1 and supports control over the number of UEs accessing the network slice. As an example, the seventh request message_1 may carry S-NSSAI and NSACF service capability indication information to identify the network slice. The NSACF service capability indication information indicates that the NSACF requested by SMF+PGW-C_1 supports control over the number of UEs accessing the network slice. For ease of description, this NSACF will be referred to as NSACF_1 below.

[0312] One possible implementation is that SMF+PGW-C_1 can call the NRF service operation Nnrf_NFDiscoveryrequest.

[0313] Step 805: NRF sends the seventh response message _1 to SMF+PGW-C_1 according to the seventh request message _1.

[0314] The seventh response message_1 carries information about NSACF_1. This information may include the address of NSACF_1. NSACF_1 is an NSACF serving the network slice identified by the S-NSSAI carried in the seventh request message_1, and it supports control over the number of UEs accessing the network slice identified by the S-NSSAI.

[0315] One possible implementation is that the NRF returns an Nnrf_NFDiscovery response to the SMF+PGW-C_1, carrying information about the NSACF_1, such as the address information of the NSACF_1.

[0316] Optionally, SMF+PGW-C_1 stores the information of NSACF_1 returned by NRF in the context.

[0317] Step 806: SMF+PGW-C_1 determines NSACF_1 based on the seventh response message_1 and sends the eighth request message_1 to NSACF_1.

[0318] The eighth request message_1 may carry the UE ID, update flag_1, and S-NSSAI. The UE ID may be determined by SMF+PGW-C_1 based on the session creation request message. For example, if the session creation request message carries the UE ID, this UE ID may be the UE's IMSI. The update flag_1 is used to indicate the increase in the number of UEs corresponding to the network slice identified by S-NSSAI, for example, incrementing the UE number by 1.

[0319] Optionally, the eighth request message_1 may also carry information related to session_1. The information related to session_1 may include the identifier of SMF+PGW-C_1 and / or the identifier of session_1. The identifier of SMF+PGW-C_1 may be the ID of SMF+PGW-C_1, and the identifier of session_1 is used to identify the session_1, such as PDU session ID_1. The PDU session ID_1 may be included in the session creation request message.

[0320] One possible implementation is that SMF+PGW-C_1 sends an Nnsacf_NumberOfUEsPerSliceAvailabilityCheckAndUpdate request to NSACF_1.

[0321] Optionally, in one possible implementation, when SMF+PGW-C_1 determines that PDN connection_1 is the first PDN connection associated with S-NSSAI that SMF+PGW-C_1 serves for the UE, then SMF+PGW-C_1 executes steps 806-808. Specifically, SMF+PGW-C_1 can determine whether PDN connection_1 is the first PDN connection established by the UE associated with the network slice based on the context information stored in SMF+PGW-C_1. For example, SMF+PGW-C_1 stores the context information of all PDN connections currently established by the UE. If there are other PDN connections in the context that are associated with the same network slice as PDN connection_1, it means that PDN connection_1 is not the first PDN connection established by the UE associated with the network slice. For example, the UE has already established PDN connection_1', which is also served by SMF+PGW-C_1 and is associated with the same network slice as PDN connection_1. It should be noted that the APN corresponding to PDN connection_1' can be different from the APN corresponding to PDN connection_1. If there are no other PDN connections in the context that are associated with the same network slice as PDN connection_1, it means that PDN connection_1 is the first PDN connection initiated by the UE that is associated with the network slice and served by SMF+PGW-C_1.

[0322] If, based on the above description, SMF+PGW-C_1 determines that PDN connection_1 is not the first PDN connection associated with S-NSSAI that SMF+PGW-C_1 serves for the UE, for example, if the UE has already established PDN connection_1' on SMF+PGW-C_1 and that PDN connection_1' is associated with the same S-NSSAI, then the UE number control procedure corresponding to the network slice identified by the S-NSSAI has already been executed in the establishment procedure of PDN connection_1'. Since the current PDN connection_1 is established by the same UE and is associated with the same network slice, SMF+PGW-C_1 does not need to request NSACF_1 to perform user number control for the network slice again, that is, steps 806-808 do not need to be executed.

[0323] It should be noted that during the establishment of a PDN connection, SMF+PGW-C_1 can store the PDN connection information in the local context. During the release of a PDN connection, SMF+PGW-C_1 can delete the PDN connection information in the local context.

[0324] Step 807, NSACF_1 performs admission control on the network slice according to the eighth request message_1.

[0325] One possible implementation is that NSACF_1 performs admission control on network slices, including admission control of the number of UEs (User Equipment) within the network slice, also known as UE counting, to ensure that the total number of UEs currently connected to the network slice does not exceed the maximum number of terminal devices allowed to access the network slice. NSACF_1 can store the number of UEs currently connected to the network slice, and the identifiers in this UE identifier list are used to identify the UEs currently connected to the network slice. NSACF_1 can also configure the maximum number of UEs allowed to access the network slice; that is, NSACF_1 can configure the maximum number of users allowed to access the network slice.

[0326] Specifically, if the current quota of the network slice identified by S-NSSAI is still available (i.e., the number of UEs currently accessing the network slice identified by S-NSSAI has not exceeded the maximum number), and the UE ID is not stored in the list of UE IDs already accessed by the network slice identified by S-NSSAI, then the UE can access the network slice identified by S-NSSAI. In this case, NSACF_1 increments the number of UEs accessing the network slice (e.g., increments the number of UEs accessing the network slice identified by S-NSSAI by 1) and adds the UE ID to the list of UE IDs already accessed by the network slice, thereby preserving the correspondence between UE IDs and S-NSSAI. If the current quota of the network slice identified by S-NSSAI is still available, and the UE ID is already stored in the list of UE IDs already accessed by the network slice identified by S-NSSAI, then it means that the UE has already accessed the network slice identified by S-NSSAI. In this case, NSACF_1 does not change the number of UEs in the network slice. If the current quota of the network slice identified by S-NSSAI is unavailable (i.e., the number of UEs currently accessing the network slice identified by S-NSSAI exceeds the maximum number), then the UE cannot access the network slice identified by S-NSSAI. In this case, NSACF_1 will not change the number of UEs in the network slice.

[0327] exist Figure 8 In the process shown, NSACF_1 increases the number of UEs in the network slice and adds the UE ID to the list of UE identifiers that have been accessed in the network slice, thereby saving the correspondence between UE ID and S-NSSAI.

[0328] Optionally, if the eighth request message_1 carries information related to session_1, NSACF_1 can also save the information related to session_1. For example, NSACF_1 stores configuration information or policy information: this configuration information or policy information is used to instruct NSACF_1 to store information related to session_1.

[0329] Step 808, NSACF_1 sends the eighth response message_1 to SMF+PGW-C_1.

[0330] The eighth response message_1 is used to indicate the result of admission control for the network slice. This result can include: admission control for the network slice was successful or failed. If admission control for the network slice was successful, it indicates that the count of the number of UEs was successful; if admission control for the network slice failed, it indicates that the count of the number of UEs failed. The eighth response message_1 can also carry a failure reason value, which indicates that the number of UEs already connected to the network slice has reached its maximum value. In this example, the eighth response message_1 can indicate that admission control for the network slice was successful.

[0331] One possible implementation is that NSACF_1 sends an Nnsacf_NumberOfUEsPerSliceAvailabilityCheckAndUpdate response to SMF+PGW-C_1, and NSACF_1 carries the result of performing admission control on the network slice in the message it sends.

[0332] Step 809, SMF+PGW-C_1 sends the fifth request message_1 to NRF.

[0333] The fifth request message_1 is used to request an NSACF that serves the network slice associated with PDN connection_1 and supports control over the number of sessions established on the network slice. As an example, the fifth request message_1 may carry NS-NSSAI and NSACF service capability indication information to identify the network slice. The NSACF service capability indication information indicates that the NSACF requested by SMF+PGW-C_1 supports control over the number of sessions established on the network slice identified by the S-NSSAI. For ease of description, this NSACF will be referred to as NSACF_2 below.

[0334] One possible implementation is that SMF+PGW-C_1 can call the NRF service operation Nnrf_NFDiscoveryrequest.

[0335] Step 810: NRF sends a fifth response message _1 to SMF+PGW-C_1 based on the fifth request message _1.

[0336] The fifth response message_1 carries information about NSACF_2. This information may include the address of NSACF_2. NSACF_2 is an NSACF serving the network slice identified by the S-NSSAI carried in the fifth request message_1, and it supports control over the number of sessions established on the network slice identified by the S-NSSAI.

[0337] One possible implementation is that the NRF returns an Nnrf_NFDiscovery response to the SMF+PGW-C_1, carrying information about NSACF_2, such as the address information of NSACF_2.

[0338] Optionally, SMF+PGW-C_1 stores the information of NSACF_2 returned by NRF in the context.

[0339] It should be noted that this application does not restrict the order in which SMF+PGW-C_1 requests the discovery of NSACF_1 and NSACF_2 from the NRF. One possible implementation is as follows: Figure 8 As shown, SMF+PGW-C_1 can first request the NRF to discover NSACF_1, and after successfully counting the number of UEs, it can then request the NRF to discover NSACF_2. That is, SMF+PGW-C_1 sends two request messages to the NRF to obtain information about NSACF_1 and NSACF_2 respectively. Another possible implementation is that SMF+PGW-C_1 triggers the NRF to discover NSACF_1 and NSACF_2 with a single request message, and the NRF returns the information about both NSACF_1 and NSACF_2 in a single response message.

[0340] Step 811: SMF+PGW-C_1 determines NSACF_2 based on the fifth response message_1 and sends the sixth request message_1 to NSACF_2.

[0341] The sixth request message_1 may carry an update flag_2, S-NSSAI, and information related to session_1. The update flag_2 indicates an increase in the number of sessions corresponding to the network slice identified by S-NSSAI, for example, incrementing the session count by 1. Information related to session_1 may include the identifier of SMF+PGW-C_1 and / or the identifier of session_1. The identifier of SMF+PGW-C_1 may be the ID of SMF+PGW-C_1, and the identifier of session_1 is used to identify this session_1, such as PDU session ID_1. The PDU session ID_1 may be included in the session creation request message.

[0342] Optionally, the sixth request message_1 may also carry the UE ID, which may be determined by SMF+PGW-C_1 based on the session creation request message or context.

[0343] One possible implementation is that SMF+PGW-C_1 sends an Nnsacf_NumberOfPDUsPerSliceAvailabilityCheckAndUpdate request to NSACF_2.

[0344] Step 812, NSACF_2 performs admission control on the network slice according to the sixth request message_1.

[0345] One possible implementation is that NSACF_2 performs admission control on network slices, including session count control, to ensure that the total number of sessions currently established in a network slice does not exceed the maximum number of sessions allowed for that network slice. NSACF_2 can store the number of sessions currently established in a network slice. NSACF_2 can also configure the maximum number of sessions allowed for a network slice; that is, NSACF_2 can configure the maximum number of users allowed to access a network slice and the maximum number of sessions allowed to be established in a network slice.

[0346] Specifically, if the current quota of the network slice identified by S-NSSAI is still available (i.e., the number of sessions currently established by the network slice identified by S-NSSAI has not exceeded the maximum number), the UE can establish a new session within the network slice identified by S-NSSAI. In this case, NSACF_2 increments the number of sessions in the network slice (e.g., the number of sessions accessing the network slice identified by S-NSSAI is increased by 1) and saves the correspondence between session_1 and S-NSSAI. If the current quota of the network slice identified by S-NSSAI is unavailable (i.e., the number of sessions currently established by the network slice identified by S-NSSAI exceeds the maximum number), the UE cannot establish a new session within the network slice identified by S-NSSAI. In this case, NSACF_2 does not change the number of sessions in the network slice with available quota.

[0347] exist Figure 8 In the illustrated process, NSACF_2 increases the number of network slice sessions and saves the correspondence between session_1-related information and S-NSSAI. If the UE ID is carried in the sixth request message_1, NSACF_2 can save the correspondence between the UE ID, S-NSSAI, and session_1-related information.

[0348] Step 813, NSACF_2 sends the sixth response message_1 to SMF+PGW-C_1.

[0349] The sixth response message_1 is used to determine the result of admission control applied to the network slice. This result can include: admission control was successful or failed. If admission control was successful, it indicates that the session count was successful; if admission control failed, it indicates that the session count failed. The sixth response message_1 can also carry a failure reason value, which indicates that the number of sessions established on the network slice has reached its maximum value. Figure 8 In the process shown, the sixth response message _1 can indicate that admission control for the network slice was successfully performed.

[0350] One possible implementation is that NSACF_2 sends an Nnsacf_NumberOfPDUsPerSliceAvailabilityCheckAndUpdate response to SMF+PGW-C_1, with NSACF_2 carrying the result of performing admission control on the network slice in the message it sends.

[0351] Step 814, SMF+PGW-C_1 sends Ninth Request Message_1 to NSACF_1.

[0352] The reason for SMF+PGW-C_1 executing step 814 can be any of the following:

[0353] 1) The eighth request message _1 did not carry information related to session _1;

[0354] 2) The eighth request message _1 carries information related to session _1, but the sixth response message _1 indicates that the session count failed.

[0355] If the reason for SMF+PGW-C_1 executing step 814 is due to reason 1 above, the ninth request message_1 can exist in the following two situations:

[0356] a) If the sixth response message_1 indicates that the session count was successful, then the ninth request message_1 may carry the UE ID, S-NSSAI, and session_1-related information. The UE ID may be determined based on the context. Optionally, the ninth request message_1 may also carry first indication information, used to instruct NSACF_1 to store the session_1-related information; that is, NSACF_1 stores the session_1-related information. This can be understood as follows: if NSACF-2 returns a result indicating that the session count was successful, it means that the current network resources allow the UE to establish a PDN connection on this network slice, then NSACF_1 needs to store the session_1-related information. In this case, the ninth request message_1 may correspond to the second request message involved in step 402 above.

[0357] b) If the sixth response message_1 indicates that the session count has failed, the ninth request message_1 may carry the UE ID, S-NSSAI, and first indication information (such as update flag_1). The UE ID may be determined based on the context. The first indication information indicates a reduction in the number of UEs corresponding to the network slice identified by S-NSSAI, such as decrementing the number of UEs by 1.

[0358] If the reason SMF+PGW-C_1 executes step 814 is due to reason 2 above, then the ninth request message_1 can carry the UE ID, S-NSSAI, and first indication information (such as update flag_1). The UE ID can be determined based on the context. The first indication information indicates a reduction in the number of UEs corresponding to the network slice identified by S-NSSAI, such as decrementing the number of UEs by 1. This can be understood as follows: if NSACF-2 returns a session count failure, it means that the current network resources do not allow the UE to establish a PDN connection on that network slice. Further, this can be understood as the session establishment failing, and the UE no longer accessing that network slice. At this time, the ninth request message_1 can correspond to the above... Figure 4 The first request message in the message.

[0359] One possible implementation is that SMF+PGW-C_1 sends an Nnsacf_NumberOfUEsPerSliceAvailabilityCheckAndUpdate request to NSACF_1.

[0360] Step 815: NSACF_1 determines whether to store session_1 related information based on the ninth request message_1.

[0361] One possible implementation is that if the ninth request message_1 contains information related to session_1, then NSACF_1 can maintain the number of UEs corresponding to the network slice identified by S-NSSAI and save the information related to session_1. If the first indication information in the ninth request message_1 indicates a reduction in the number of UEs, then NSACF_1 determines whether the current UE has other sessions. Since the context stored by NSACF_1 only contains information related to session_1 (i.e., NSACF_1 only stores information about PDN connection_1), NSACF_1 can reduce the number of UEs corresponding to the network slice identified by S-NSSAI, and at the same time, NSACF_1 deletes the information related to session_1.

[0362] Step 816, NSACF_1 sends the ninth response message_1 to SMF+PGW-C_1.

[0363] If the ninth request message_1 contains information related to session_1, then the ninth response message_1 is used to indicate that the session information was successfully stored; if the ninth request message_1 is used to request admission control on the number of UEs accessing the network slice (e.g., to indicate a reduction in the number of UEs corresponding to the network slice identified by S-NSSAI), then the ninth response message_1 is used to indicate the result of admission control on the number of UEs accessing the network slice.

[0364] It should be noted that if NSACF_1 saves information related to session_1 in step 807, steps 814-816 may not be executed when the sixth response message_1 indicates that the session count is successful.

[0365] Step 817: Perform the remaining procedures for establishing the PDN connection.

[0366] Since Example 3 uses the establishment of two PDN connections as an example, and this is the establishment of the first PDN connection, NSACF_1 will increase the number of UEs corresponding to this network slice and save the mapping relationship between UE ID, S-NSSAI, and session_1 related information. NSACF_2 will increase the number of sessions corresponding to this network slice and save the mapping relationship between S-NSSAI and session_1 related information. If the UE ID is carried in the sixth request message_1, NSACF_2 can save the mapping relationship between UE ID, S-NSSAI, and session_1 related information.

[0367] At this point, the establishment of PDN connection_1 is complete, and NSACF_1 stores the correspondence between UE ID, S-NSSAI, and session_1 related information.

[0368] Figure 9 This is another example of the network slice admission control method provided in this application. Figure 9SMF+PGW-C_1 in the above text can correspond to the second network element mentioned above, and NSACF_1 can correspond to the above text. Figure 4 The first network element in the above, NSACF_2, can correspond to the third network element involved in steps 402-403 above.

[0369] according to Figure 8 As shown in the process, the UE has successfully established PDN connection_1, which is provided by SMF+PGW-C_1. The UE can continue to initiate the PDN connection establishment process to the network. For ease of description, the SMF+PGW-C serving PDN connection_2 will be referred to as SMF+PGW-C_2 in the following text.

[0370] Step 901: The UE initiates the PDN connection establishment process.

[0371] Step 902, SMF+PGW-C_2 determines the network slice associated with the PDN connection.

[0372] Step 903: SMF+PGW-C_2 determines whether the network slice needs to execute the NSAC process based on the configuration information.

[0373] The implementation of steps 901-903 is the same as that of steps 601-603. Please refer to the description of steps 601-603 for details.

[0374] If SMF+PGW-C_2 determines that the network slice requires the NSAC procedure, then proceed to steps 904-916. If SMF+PGW-C_2 determines that the network slice does not require the NSAC procedure, then skip steps 904-916 and proceed directly to step 917.

[0375] Step 904: SMF+PGW-C_2 sends the seventh request message_2 to NRF.

[0376] The seventh request message_2 is used to request an NSACF that serves the network slice associated with PDN connection_2 and supports control over the number of UEs accessing the network slice. As an example, the seventh request message_2 may carry S-NSSAI and NSACF service capability indication information to identify the network slice. The NSACF service capability indication information indicates that the NSACF requested by SMF+PGW-C_2 supports control over the number of UEs accessing the network slice. For ease of description, this NSACF will be referred to as NSACF_1 below.

[0377] One possible implementation is that SMF+PGW-C_2 can call the NRF service operation Nnrf_NFDiscoveryrequest.

[0378] Step 905: NRF sends the seventh response message _2 to SMF+PGW-C_2 according to the seventh request message _2.

[0379] The seventh response message_2 carries information about NSACF_1. NSACF_1 is the NSACF serving the network slice identified by the S-NSSAI carried in the seventh request message_2, and it supports control over the number of UEs accessing the network slice identified by the S-NSSAI. The NSACF in step 905 is the same as the NSACF in step 805.

[0380] Optionally, SMF+PGW-C_2 stores the information of NSACF_1 returned by NRF in the context.

[0381] Step 906: SMF+PGW-C_2 determines NSACF_1 based on the seventh response message_2 and sends the eighth request message_2 to NSACF_1.

[0382] The eighth request message_2 may carry the UE ID, update flag_1, and S-NSSAI. The UE ID may be determined by SMF+PGW-C_2 based on the session creation request message. For example, if the session creation request message carries the UE ID, this UE ID may be the UE's IMSI. The update flag_1 is used to indicate the increase in the number of UEs corresponding to the network slice identified by S-NSSAI, for example, incrementing the UE number by 1.

[0383] Optionally, the eighth request message_2 may also carry information related to session_2. The information related to session_2 may include the identifier of SMF+PGW-C_2 and / or the identifier of session_2. The identifier of SMF+PGW-C_2 may be the ID of SMF+PGW-C_2, and the identifier of session_2 is used to identify the session_2, such as PDU session ID_2. The PDU session ID_2 may be included in the session creation request message.

[0384] One possible implementation is that SMF+PGW-C_2 sends an Nnsacf_NumberOfUEsPerSliceAvailabilityCheckAndUpdate request to NSACF_1.

[0385] Optionally, in one possible implementation, when SMF+PGW-C_2 determines that PDN connection_2 is the first PDN connection associated with S-NSSAI served by SMF+PGW-C_2 for the UE, then SMF+PGW-C_2 executes steps 906-908. Specifically, SMF+PGW-C_2 can determine whether PDN connection_2 is the first PDN connection established by the UE associated with the network slice based on the context information stored in SMF+PGW-C_2. For example, SMF+PGW-C_2 stores the context information of all PDN connections currently established by the UE. If there are other PDN connections in the context that are associated with the same network slice as PDN connection_2, then it means that PDN connection_2 is not the first PDN connection established by the UE associated with the network slice. For example, the UE has already established PDN connection_2', which is also served by SMF+PGW-C_2 and is associated with the same network slice as PDN connection_2. It should be noted that the APN corresponding to PDN connection_2' can be different from the APN corresponding to PDN connection_2. If there are no other PDN connections in the context stored by SMF+PGW-C_2 that are associated with the same network slice as PDN connection_2, then PDN connection_2 is the first PDN connection initiated by the UE that is associated with the network slice and served by SMF+PGW-C_2.

[0386] If, based on the above description, SMF+PGW-C_2 determines that PDN connection_2 is not the first PDN connection associated with S-NSSAI that SMF+PGW-C_2 serves for the UE, for example, if the UE has already established PDN connection_2' and the PDN connection_2' is associated with the same S-NSSAI, then the UE number control procedure corresponding to the network slice identified by the S-NSSAI has already been executed in the establishment procedure of PDN connection_2'. Since the current PDN connection_2 is established by the same UE and associated with the same network slice, SMF+PGW-C_2 does not need to request NSACF_1 to perform user number control for the network slice again, that is, steps 906-908 do not need to be executed.

[0387] It should be noted that during the establishment of a PDN connection, SMF+PGW-C_2 can store the PDN connection information in the local context. During the release of a PDN connection, SMF+PGW-C_2 can delete the PDN connection information in the local context.

[0388] Step 907, NSACF_1 performs admission control on the network slice according to the eighth request message_2.

[0389] One possible implementation is that NSACF_1 performs admission control on network slices, including admission control of the number of UEs (User Equipment) within the network slice, also known as UE counting, to ensure that the total number of UEs currently connected to the network slice does not exceed the maximum number of terminal devices allowed to access the network slice. NSACF_1 can store the number of UEs currently connected to the network slice, and the identifiers in this UE identifier list are used to identify the UEs currently connected to the network slice. NSACF_1 can also configure the maximum number of UEs allowed to access the network slice; that is, NSACF_1 can configure the maximum number of users allowed to access the network slice.

[0390] Specifically, if the current quota of the network slice identified by S-NSSAI is still available (i.e., the number of UEs currently accessing the network slice identified by S-NSSAI has not exceeded the maximum number), and the UE ID is not stored in the list of UE IDs already accessed by the network slice identified by S-NSSAI, then the UE can access the network slice identified by S-NSSAI. In this case, NSACF_1 increments the number of UEs accessing the network slice (e.g., increments the number of UEs accessing the network slice identified by S-NSSAI by 1) and adds the UE ID to the list of UE IDs already accessed by the network slice, thereby preserving the correspondence between UE IDs and S-NSSAI. If the current quota of the network slice identified by S-NSSAI is still available, and the UE ID is already stored in the list of UE IDs already accessed by the network slice identified by S-NSSAI, then it means that the UE has already accessed the network slice identified by S-NSSAI. In this case, NSACF_1 does not change the number of UEs in the network slice. If the current quota of the network slice identified by S-NSSAI is unavailable (i.e., the number of UEs currently accessing the network slice identified by S-NSSAI exceeds the maximum number), then the UE cannot access the network slice identified by S-NSSAI. In this case, NSACF_1 will not change the number of UEs in the network slice.

[0391] exist Figure 9 In the process shown, NSACF_1 determines that the UE has accessed the network slice identified by S-NSSAI based on the correspondence between the UE ID and S-NSSAI stored in the context information. In this case, NSACF_1 does not need to count the number of UEs corresponding to the network slice, that is, the number of UEs in the network slice remains unchanged.

[0392] Optionally, if the eighth request message_2 carries information related to session_2, NSACF_1 can also store the session_2 related information. For example, NSACF_1 stores configuration information or policy information: this configuration information or policy information is used to instruct NSACF_1 to store session_2 related information.

[0393] Step 908, NSACF_1 sends the eighth response message_2 to SMF+PGW-C_2.

[0394] The eighth response message_2 is used to indicate the result of admission control for the network slice. This result can include: admission control for the network slice was successful or failed. If admission control for the network slice was successful, it indicates that the count of the number of UEs was successful; if admission control for the network slice failed, it indicates that the count of the number of UEs failed. The eighth response message_2 can also carry a failure reason value, which indicates that the number of UEs already connected to the network slice has reached its maximum value. In this example, the eighth response message_2 can indicate that admission control for the network slice was successful.

[0395] One possible implementation is that NSACF_1 sends an Nnsacf_NumberOfUEsPerSliceAvailabilityCheckAndUpdate response to SMF+PGW-C_2, and NSACF_1 carries the result of performing admission control on the network slice in the message it sends.

[0396] Step 909: If the eighth response message_2 indicates that the UE count is successful, SMF+PGW-C_2 sends the fifth request message_2 to NRF.

[0397] The fifth request message_2 is used to request an NSACF that serves the network slice associated with PDN connection_2 and supports control over the number of sessions established on the network slice. As an example, the fifth request message_2 may carry NS-NSSAI and NSACF service capability indication information to identify the network slice. The NSACF service capability indication information indicates that the NSACF requested by SMF+PGW-C_2 supports control over the number of sessions established on the network slice identified by the S-NSSAI. For ease of description, this NSACF will be referred to as NSACF_2 below.

[0398] One possible implementation is that SMF+PGW-C_1 can call the NRF service operation Nnrf_NFDiscoveryrequest.

[0399] Step 910: NRF sends Fifth Response Message 2 to SMF+PGW-C_2 based on Fifth Request Message 2.

[0400] The fifth response message_2 carries information about NSACF_2. This information may include the address of NSACF_2. NSACF_2 is an NSACF serving the network slice identified by the S-NSSAI carried in the fifth request message_2, and it supports control over the number of sessions established on the network slice identified by the S-NSSAI. The NSACF in step 910 is the same as the NSACF in step 810.

[0401] One possible implementation is that the NRF returns an Nnrf_NFDiscovery response to the SMF+PGW-C_2, carrying information about the NSACF_2, such as the address information of the NSACF_2.

[0402] Optionally, SMF+PGW-C_2 stores the information of NSACF_2 returned by NRF in the context.

[0403] It should be noted that this application does not restrict the order in which SMF+PGW-C_2 requests the discovery of NSACF_1 and NSACF_2 from the NRF. One possible implementation is as follows: Figure 9 As shown, SMF+PGW-C_2 can first request the NRF to discover NSACF_1, and after successfully counting the number of UEs, it can then request the NRF to discover NSACF_2. That is, SMF+PGW-C_2 sends two request messages to the NRF to obtain information about NSACF_1 and NSACF_2 respectively. Another possible implementation is that SMF+PGW-C_2 triggers the NRF to discover NSACF_1 and NSACF_2 with a single request message, and the NRF returns the information about both NSACF_1 and NSACF_2 in a single response message.

[0404] Step 911: SMF+PGW-C_2 determines NSACF_2 based on the fifth response message_2 and sends the sixth request message_2 to NSACF_2.

[0405] The sixth request message_2 may carry an update flag_2, S-NSSAI, and information related to session_2. The update flag_2 indicates an increase in the number of sessions corresponding to the network slice identified by S-NSSAI, for example, incrementing the session count by 1. Information related to session_2 may include the identifier of SMF+PGW-C_2 and / or the identifier of session_2. The identifier of SMF+PGW-C_2 may be the ID of SMF+PGW-C_2, and the identifier of session_2 is used to identify this session_2, such as PDU session ID_2. The PDU session ID_2 may be included in the session creation request message.

[0406] Optionally, the sixth request message_2 may also carry the UE ID, which may be determined by SMF+PGW-C_2 based on the session creation request message or the context.

[0407] One possible implementation is that SMF+PGW-C_2 sends an Nnsacf_NumberOfPDUsPerSliceAvailabilityCheckAndUpdate request to NSACF_2.

[0408] Step 912, NSACF_2 performs admission control on the network slice according to the sixth request message_2.

[0409] One possible implementation is that NSACF_2 performs admission control on network slices, including session count control, to ensure that the total number of sessions currently established in a network slice does not exceed the maximum number of sessions allowed for that network slice. NSACF_2 can store the number of sessions currently established in a network slice. NSACF_2 can also configure the maximum number of sessions allowed for a network slice; that is, NSACF_2 can configure the maximum number of users allowed to access a network slice and the maximum number of sessions allowed to be established in a network slice.

[0410] Specifically, if the current quota of the network slice identified by S-NSSAI is still available (i.e., the number of sessions currently established by the network slice identified by S-NSSAI has not exceeded the maximum number), the UE can establish a new session within the network slice identified by S-NSSAI. In this case, NSACF_2 increments the number of sessions in the network slice (e.g., the number of sessions accessing the network slice identified by S-NSSAI is increased by 1) and saves the correspondence between session_1 and S-NSSAI. If the current quota of the network slice identified by S-NSSAI is unavailable (i.e., the number of sessions currently established by the network slice identified by S-NSSAI exceeds the maximum number), the UE cannot establish a new session within the network slice identified by S-NSSAI. In this case, NSACF_2 does not change the number of sessions in the network slice with available quota.

[0411] exist Figure 9 In the illustrated process, NSACF_2 increases the number of network slice sessions and saves the correspondence between session_2-related information and S-NSSAI. If the UE ID is carried in the sixth request message_2, NSACF_2 can save the correspondence between the UE ID, S-NSSAI, and session_2-related information.

[0412] Step 913, NSACF_2 sends the sixth response message_2 to SMF+PGW-C_2.

[0413] The sixth response message, _2, indicates the result of admission control applied to the network slice. This result can include: admission control was successful or failed. If admission control was successful, it means the session count was successful; if it failed, it means the session count failed. The sixth response message, _2, can also carry a failure reason value, indicating that the number of sessions established on the network slice has reached its maximum. Figure 9 In the process shown, the sixth response message _2 can indicate that admission control for the network slice was successfully performed.

[0414] One possible implementation is that NSACF_2 sends an Nnsacf_NumberOfPDUsPerSliceAvailabilityCheckAndUpdate response to SMF+PGW-C_2, with NSACF_2 carrying the result of performing admission control on the network slice in the message it sends.

[0415] Step 914, SMF+PGW-C_2 sends Ninth Request Message_2 to NSACF_1.

[0416] Similarly, the reason for SMF+PGW-C_2 executing step 914 can be any of the following:

[0417] 1) The eighth request message _2 did not carry information related to session _2;

[0418] 2) The eighth request message _2 carries information related to session _2, but the sixth response message _2 indicates that the session count failed.

[0419] If the reason for SMF+PGW-C_2 executing step 914 is the aforementioned reason 1), then the ninth request message_2 can exist in the following two situations:

[0420] a) If the sixth response message_2 indicates that the session count was successful, then the ninth request message_2 may carry the UE ID, S-NSSAI, and session_2-related information. The UE ID may be determined based on the context. Optionally, the ninth request message_2 may also carry first indication information to instruct NSACF_1 to store the session_2-related information; that is, NSACF_1 stores the session_2-related information. This can be understood as follows: if NSACF_2 returns a successful session count, it means that the current network resources allow the UE to establish a PDN connection on this network slice, then NSACF_1 needs to store the session_2-related information. In this case, the ninth request message_2 may correspond to the second request message involved in step 402 above.

[0421] b) If the sixth response message_2 indicates that the session count has failed, the ninth request message_2 may carry the UE ID, S-NSSAI, and first indication information (such as update flag_1). The UE ID may be determined based on the context. The first indication information indicates a reduction in the number of UEs corresponding to the network slice identified by S-NSSAI, such as decrementing the number of UEs by 1.

[0422] If the reason for SMF+PGW-C_2 executing step 914 is reason 2 above, then the ninth request message_2 can carry the UE ID, S-NSSAI, and first indication information (such as update flag_1). The UE ID can be determined based on the context. The first indication information indicates a reduction in the number of UEs corresponding to the network slice identified by S-NSSAI, such as decrementing the number of UEs by 1. This can be understood as follows: if NSACF-2 returns a session count failure, it means that the current network resources do not allow the UE to establish a PDN connection on that network slice. Further, this can be understood as the session establishment failing, and the UE no longer accessing that network slice. At this time, the ninth request message_2 can correspond to the above... Figure 4 The first request message in the message.

[0423] One possible implementation is that SMF+PGW-C_2 sends an Nnsacf_NumberOfUEsPerSliceAvailabilityCheckAndUpdate request to NSACF_1.

[0424] Step 915: NSACF_1 determines whether to store session_2-related information based on the ninth request message_2.

[0425] In one possible implementation, if the ninth request message_2 contains information related to session_2, then NSACF_1 can maintain the number of UEs corresponding to the network slice identified by S-NSSAI and save the information related to session_2. If the first indication information in the ninth request message_2 indicates a reduction in the number of UEs, then NSACF_1 determines whether the current UE has other sessions. Since the context stored by NSACF_1 includes information related to both session_1 and session_2, NSACF_1 cannot reduce the number of UEs corresponding to the network slice identified by S-NSSAI. Simultaneously, NSACF_1 deletes the information related to session_2, i.e., deletes the information related to session_2, and retains the information related to session_1.

[0426] exist Figure 9 In the process shown, NSACF_1 maintains the number of UEs corresponding to the network slice identified by S-NSSAI, and decides whether to save the information related to session_2 based on the parameters carried in the ninth request message_2.

[0427] Step 916, NSACF_1 sends the ninth response message_2 to SMF+PGW-C_2.

[0428] If the ninth request message_2 contains UE session-related information, then the ninth response message_2 is used to indicate that the session information was successfully stored. If the ninth request message_2 is used to perform admission control on the number of UEs in the network slice, then the ninth response message_2 is used to indicate the result of the admission control on the number of UEs in the network slice.

[0429] It should be noted that if NSACF_1 saves information related to session_2 in step 907, steps 914-916 may not be executed when the sixth response message_2 indicates that the session count is successful.

[0430] Step 917: Perform the remaining procedures for establishing the PDN connection.

[0431] This completes the establishment of PDN connection_2. NSACF_1 stores the correspondence between UE ID, S-NSSAI, session_1 related information and session_2 related information.

[0432] As described above, regarding the process of determining the number of UEs and sessions triggered by establishing a PDN connection, in Example 3, SMF+PGW-C first interacts with NSACF_1 (the NSACF responsible for UE count control) to trigger an update of the UE count. If the UE count is not exceeded, SMF+PGW-C then interacts with NSACF_2 (the NSACF responsible for session count control) to trigger an update of the session count. Once the session count update is successful, SMF+PGW-C needs to interact with NSACF_1 again to trigger NSACF_1 to maintain the session count status so that NSACF_1 can subsequently determine whether the number of UEs needs to be reduced. This enables network slice admission control in interoperability scenarios.

[0433] It should be noted that, Figure 8 and Figure 9 The examples all take the SMF+PGW-C interacting first with the NSACF responsible for UE number control, then with the NSACF responsible for session number control, and finally with the NSACF responsible for UE number control. However, the embodiments of this application are not limited to this. For example, the SMF+PGW-C may also interact first with the NSACF responsible for session number control, then with the NSACF responsible for UE number control, and finally with the NSACF responsible for session number control.

[0434] Example 4

[0435] In Example 4, the UE initiates the release process of multiple PDN connections, and the multiple PDN connections are associated with the same network slice. The NSACF responsible for the quota management of the number of UEs in the network slice is different from the NSACF responsible for the quota management of the number of sessions in the network slice. Figure 10 Take the example of a UE establishing two PDN connections. Assume that, according to Example 3, the UE has established two PDN connections (PDN connection_1 and PDN connection_2) for the same network slice. At a certain moment, the UE initiates a PDN connection release procedure to the network.

[0436] Figure 10 This is another example of the network slice admission control method provided in this application. Figure 10 SMF+PGW-C_1 and SMF+PGW-C_2 in the above text can correspond to the above text. Figure 4 The second network element, NSACF_1, can correspond to the one mentioned above. Figure 4 The first network element in the above, NSACF_2, can correspond to the third network element involved in steps 402-403 above.

[0437] Step 1001: The UE initiates the release procedure for PDN connection_1.

[0438] The implementation method of step 1001 is the same as that of step 701. Please refer to the description of step 701, and it will not be repeated here.

[0439] Step 1002, SMF+PGW-C_1 sends the sixth request message_3 to NSACF_2.

[0440] The sixth request message_3 may carry S-NSSAI, update flag_2, and information related to session_1. Update flag_2 indicates a reduction in the number of sessions corresponding to the network slice identified by S-NSSAI, for example, decreasing the number of sessions by 1. Information related to session_1 may include the identifier of SMF+PGW-C_1 and / or the identifier of session_1. The identifier of SMF+PGW-C_1 may be the ID of SMF+PGW-C_1, and the identifier of session_1 is used to identify this session_1, such as PDU session ID_1. PDU session ID_1 may be included in the session creation request message.

[0441] Optionally, the sixth request message_3 may also carry a UE ID, which may be determined by SMF+PGW-C_1 based on the delete session request message. For example, the UE ID may be the UE's IMSI.

[0442] One possible implementation is that if SMF+PGW-C_1 stores the information of NSACF_2 in the context, then SMF+PGW-C_1 can directly determine NSACF_2 based on the information of NSACF_2.

[0443] As an alternative implementation, if SMF+PGW-C_1 does not store NSACF_2 information in the context, then SMF+PGW-C_1 can request the NRF to discover NSACF_2. This method can be referenced from steps 809 and 810 above.

[0444] One possible implementation is that SMF+PGW-C_1 sends an Nnsacf_NumberOfPDUsPerSliceAvailabilityCheckAndUpdate request to NSACF_2.

[0445] Step 1003: NSACF_2 performs admission control on the network slice according to the sixth request message_3.

[0446] One possible implementation is that NSACF_2 performs admission control on network slices, including admission control of the number of sessions on network slices, which can also be called session counting. Specifically, NSACF_2 reduces the number of sessions corresponding to the network slice identified by S-NSSAI (for example, NSACF_2 will decrement the number of sessions established within the network slice identified by S-NSSAI by 1) and removes the SMF+PGW-C ID_1 identifier from the context information.

[0447] Step 1004: NSACF_2 sends the sixth response message_3 to SMF+PGW-C_1.

[0448] The sixth response message_3 is used to indicate the result of admission control applied to the network slice. This result can include: admission control applied to the network slice was successful or failed. If admission control applied to the network slice was successful, it indicates that the session count was successful; if admission control applied to the network slice failed, it indicates that the session count failed. In step 1004, the sixth response message_3 can indicate that admission control applied to the network slice was successful.

[0449] One possible implementation is that NSACF_2 sends an Nnsacf_NumberOfPDUsPerSliceAvailabilityCheckAndUpdate response to SMF+PGW-C_1, with NSACF_2 carrying the result of performing admission control on the network slice in the message it sends.

[0450] Step 1005: SMF+PGW-C_1 sends the first request message_1 to NSACF_1.

[0451] The first request message_1 may carry the UE ID, S-NSSAI, update flag_1, and information related to session_1. The UE ID may be determined by SMF+PGW-C_1 based on the delete session request message or context. The update flag_1 is used to indicate a reduction in the number of UEs corresponding to the network slice identified by S-NSSAI, for example, decrementing the number of UEs by 1. The information related to session_1 may include the identifier of SMF+PGW-C_1 and / or the identifier of session_1. The identifier of SMF+PGW-C_1 may be the ID of SMF+PGW-C_1, and the identifier of session_1 is used to identify the session_1, such as PDU session ID_1, which may be included in the create session request message.

[0452] One possible implementation is that if SMF+PGW-C_1 stores the information of NSACF_1 in the context, then SMF+PGW-C_1 can directly determine NSACF_1 based on the information of NSACF_1.

[0453] As an alternative implementation, if SMF+PGW-C_1 does not store NSACF_1 information in the context, then SMF+PGW-C_1 can request the NRF to discover NSACF_1. This method can be referenced in steps 804 and 805 above.

[0454] One possible implementation is that SMF+PGW-C_1 sends an Nnsacf_NumberOfPDUsPerSliceAvailabilityCheckAndUpdate request to NSACF_1.

[0455] Optionally, in one possible implementation, when SMF+PGW-C_1 determines that PDN connection_1 is the only PDN connection associated with S-NSSAI that SMF+PGW-C_1 serves for the UE, then SMF+PGW-C_1 executes steps 1005-1007. Specifically, SMF+PGW-C_1 can determine whether PDN connection_1 is the only PDN connection associated with S-NSSAI based on context information. For example, SMF+PGW-C_1 stores the context information of all PDN connections currently established by the UE. If there are other PDN connections in the context that have the same network slice as PDN connection_1, it means that after PDN connection_1 is released, there are still other PDN connections. For example, the UE currently also has PDN connection_1', which is also served by SMF+PGW-C_1 and has the same network slice as PDN connection_1. It should be noted that the APN corresponding to PDN connection_1' can be different from the APN corresponding to PDN connection_1. If there are no other PDN connections in the context that are associated with the same network slice as PDN connection_1, then PDN connection_1 is the only PDN connection that the UE initiates to release that is associated with the network slice and served by SMF+PGW-C_1.

[0456] If SMF+PGW-C_1 determines, based on the above description, that PDN connection_1 is not the only PDN connection associated with S-NSSAI released by the UE, for example, if the UE has already established PDN connection_1' and that PDN connection_1' is associated with the same S-NSSAI, then the UE number control procedure corresponding to the network slice identified by the S-NSSAI does not need to be executed. Since the current UE still has other PDN connections associated with the same network slice, SMF+PGW-C_1 does not need to request NSACF_1 to perform user number control on the network slice, that is, steps 1005-1007 can be omitted.

[0457] Step 1006: NSACF_1 performs admission control on the network slice according to the first request message_1.

[0458] One possible implementation is that NSACF_1 performs admission control on network slices, including admission control of the number of UEs within the network slice, which can also be referred to as counting the number of UEs. Specifically, NSACF_1 determines whether the current UE has a session other than session_1. If the session information related to the UE stored in the context of NSACF_1 only contains information related to session_1 (i.e., NSACF_1 only stores information about PDN connection_1), then NSACF_1 can reduce the number of UEs corresponding to the network slice identified by S-NSSAI, and at the same time, NSACF_1 deletes the information related to session_1. If the session information related to the UE stored in the context of NSACF_1 also includes information related to sessions other than session_1 (e.g., information related to session_2), then NSACF_1 deletes the information related to session_1, but does not reduce the number of UEs corresponding to the network slice identified by S-NSSAI.

[0459] Another possible implementation is that NSACF_1 first deletes the information related to session_1 from the stored upper and lower bounds. Then, NSACF_1 determines whether the current UE has other session information. If the current UE does not have other session information, that is, after deleting the information related to session_1 from the session information related to this UE, the session information related to this UE is empty, then NSACF_1 can reduce the number of UEs corresponding to the network slice identified by S-NSSAI. If the current UE has other session information, that is, after deleting the information related to session_1 from the session information related to this UE, the session information related to this UE is not empty, then NSACF_1 does not need to reduce the number of UEs corresponding to the network slice identified by S-NSSAI.

[0460] In this example, since NSACF_1 stores information related to both session_1 and session_2 for this UE ID, and the UE is currently only releasing PDN connection_1 corresponding to the information related to session_1, NSACF_1 determines that the UE still has other sessions. Therefore, there is no need to reduce the number of UEs accessing the network slice identified by S-NSSAI. NSACF_1 deletes the information related to UE session 1 and continues to maintain the mapping between UE ID, S-NSSAI, and the mapping between UE session 2. That is, the UE ID continues to be stored in the list of UE identifiers already accessing the network slice identified by S-NSSAI.

[0461] Step 1007: NSACF_1 sends the first response message_1 to SMF+PGW-C_1.

[0462] The first response message_1 is used to indicate the result of admission control for the network slice. This result can include: successful admission control for the network slice or failure of admission control for the network slice. If admission control for the network slice is successful, it indicates that the count of the number of UEs executed was successful; if admission control for the network slice fails, it indicates that the count of the number of UEs executed failed. The first response message_1 can also carry a failure reason value, which indicates that the UE has other sessions. In step 1007, the first response message_1 can indicate that admission control for the network slice failed because the UE has other sessions.

[0463] One possible implementation is that NSACF_1 sends an Nnsacf_NumberOfPDUsPerSliceAvailabilityCheckAndUpdate response to SMF+PGW-C_1, with NSACF_1 carrying the result of performing admission control on the network slice in the message it sends.

[0464] Step 1008: Perform the remaining procedures for releasing the PDN connection.

[0465] At this point, the release of PDN connection _1 is complete.

[0466] In step 1009, the UE initiates the release process of PDN connection_2.

[0467] The implementation method of step 1009 is the same as that of step 701. Please refer to the description of step 701, and it will not be repeated here.

[0468] Step 1010: SMF+PGW-C_2 sends the sixth request message_4 to NSACF_2.

[0469] The sixth request message _4 may carry S-NSSAI, update flag _2, and information related to session _2. Update flag _2 indicates a reduction in the number of sessions corresponding to the network slice identified by S-NSSAI, for example, decreasing the number of sessions by 1. Information related to session _2 may include the identifier of SMF+PGW-C_2 and / or the identifier of session _2. The identifier of SMF+PGW-C_2 may be the ID of SMF+PGW-C_2, and the identifier of session _2 is used to identify this session _2, such as PDU session ID_2. The PDU session ID_2 may be included in the session creation request message.

[0470] Optionally, the sixth request message_4 may also carry a UE ID, which may be determined by SMF+PGW-C_1 based on the delete session request message. For example, the UE ID may be the UE's IMSI.

[0471] One possible implementation is that if SMF+PGW-C_2 stores the information of NSACF_2 in the context, then SMF+PGW-C_2 can directly determine NSACF_2 based on the information of NSACF_2.

[0472] As an alternative implementation, if SMF+PGW-C_2 does not store NSACF_2 information in the context, then SMF+PGW-C_2 can request the NRF to discover NSACF_2. This method can be referenced from steps 809 and 810 above.

[0473] One possible implementation is that SMF+PGW-C_2 sends an Nnsacf_NumberOfPDUsPerSliceAvailabilityCheckAndUpdate request to NSACF_2.

[0474] Step 1011, NSACF_2 performs admission control on the network slice according to the sixth request message_4.

[0475] One possible implementation is that NSACF_2 performs admission control on network slices, including admission control of the number of sessions on network slices, which can also be called session counting. Specifically, NSACF_2 reduces the number of sessions corresponding to the network slice identified by S-NSSAI (for example, NSACF_2 will decrement the number of sessions established within the network slice identified by S-NSSAI by 1) and removes the SMF+PGW-C ID_2 identifier from the context information.

[0476] Step 1012, NSACF_2 sends the sixth response message_4 to SMF+PGW-C_2.

[0477] The sixth response message_4 is used to indicate the result of admission control applied to the network slice. This result can include: admission control applied to the network slice was successful or failed. If admission control applied to the network slice was successful, it indicates that the session count was successful; if admission control applied to the network slice failed, it indicates that the session count failed. In step 1012, the sixth response message_4 can indicate that admission control applied to the network slice was successful.

[0478] One possible implementation is that NSACF_2 sends an Nnsacf_NumberOfPDUsPerSliceAvailabilityCheckAndUpdate response to SMF+PGW-C_2, with NSACF_2 carrying the result of performing admission control on the network slice in the message it sends.

[0479] Step 1013: SMF+PGW-C_2 sends the first request message_2 to NSACF_1.

[0480] The first request message_2 may carry the UE ID, S-NSSAI, update flag_1, and session_2 related information. The UE ID may be determined by SMF+PGW-C_2 based on the delete session request message or context. The update flag_1 is used to indicate a reduction in the number of UEs corresponding to the network slice identified by S-NSSAI, for example, decrementing the number of UEs by 1. The session_2 related information may include the identifier of SMF+PGW-C_2 and / or the identifier of session_2. The identifier of SMF+PGW-C_2 may be the ID of SMF+PGW-C_2, and the identifier of session_2 is used to identify the session_2, such as PDU session ID_2, which may be included in the create session request message.

[0481] One possible implementation is that if SMF+PGW-C_2 stores the information of NSACF_1 in the context, then SMF+PGW-C_2 can directly determine NSACF_1 based on the information of NSACF_1.

[0482] As an alternative implementation, if SMF+PGW-C_2 does not store NSACF_1 information in the context, then SMF+PGW-C_2 can request the NRF to discover NSACF_1. This method can be referenced in steps 804 and 805 above.

[0483] One possible implementation is that SMF+PGW-C_2 sends an Nnsacf_NumberOfPDUsPerSliceAvailabilityCheckAndUpdate request to NSACF_1.

[0484] Optionally, in one possible implementation, when SMF+PGW-C_2 determines that PDN connection_2 is the only PDN connection associated with S-NSSAI that SMF+PGW-C_2 serves for the UE, then SMF+PGW-C_2 executes steps 1013-1015. Specifically, SMF+PGW-C_2 can determine whether PDN connection_2 is the only PDN connection associated with S-NSSAI based on context information. For example, SMF+PGW-C_2 stores the context information of all PDN connections currently established by the UE. If there are other PDN connections in the context that share the same network slice as PDN connection_2, it indicates that other PDN connections still exist after PDN connection_2 is released. For instance, the UE currently also has PDN connection_2', which is also served by SMF+PGW-C_2 and whose associated network slice is the same as that associated with PDN connection_2. It should be noted that the APN corresponding to PDN connection_2' can be different from the APN corresponding to PDN connection_2. If there are no other PDN connections in the context that are associated with the same network slice as PDN connection_2, then PDN connection_2 is the only PDN connection that the UE initiates to release that is associated with the network slice and served by SMF+PGW-C_2.

[0485] If SMF+PGW-C_2 determines, based on the above description, that PDN connection_2 is not the only PDN connection associated with S-NSSAI released by the UE, for example, if the UE has already established PDN connection_2' and this PDN connection_2' is associated with the same S-NSSAI, then the UE number control procedure corresponding to the network slice identified by the S-NSSAI does not need to be executed. Since the current UE still has other PDN connections associated with the same network slice, SMF+PGW-C_2 does not need to request NSACF_1 to perform user number control on this network slice, that is, steps 1013-1015 can be omitted.

[0486] Step 1014: NSACF_1 performs admission control on the network slice according to the first request message_2.

[0487] One possible implementation is that NSACF performs admission control on network slices, including admission control of the number of UEs per network slice, which can also be called UE counting. Specifically, NSACF_1 determines whether the current UE has a session other than session_2. If the context stored in NSACF_1 only contains information related to session_2 (i.e., NSACF_1 only stores information about PDN connection_2), then NSACF_1 can reduce the number of UEs corresponding to the network slice identified by S-NSSAI, and at the same time, NSACF_1 deletes the information related to session_2. If the context stored in NSACF_1 also includes session-related information other than that related to session_2, then NSACF_1 deletes the information related to session_2, but does not reduce the number of UEs corresponding to the network slice identified by S-NSSAI.

[0488] Another possible implementation is that NSACF_1 first deletes the information related to session_2 from the stored upper and lower bounds. Then, NSACF_1 determines whether the current UE has other session information. If the current UE does not have other session information, that is, after deleting the information related to session_2 from the session information related to this UE, the session information related to this UE is empty, then NSACF_1 can reduce the number of UEs corresponding to the network slice identified by S-NSSAI. If the current UE has other session information, that is, after deleting the information related to session_2 from the session information related to this UE, the session information related to this UE is not empty, then NSACF_1 does not need to reduce the number of UEs corresponding to the network slice identified by S-NSSAI.

[0489] In this example, since NSACF_1 currently only stores information related to session_2 for this UE ID, after deleting the information related to session_2, there are no other established sessions for this UE. Therefore, NSACF_1 can count the UEs (i.e., NSACF_1 reduces the number of UEs accessing the network slice identified by S-NSSAI) and delete the UE ID from the list of UE identifiers already accessed by the network slice in the context information.

[0490] Step 1015, NSACF_1 sends the first response message_2 to SMF+PGW-C_2.

[0491] The first response message_2 is used to indicate the result of admission control for the network slice. This result can include: successful admission control for the network slice or failure of admission control for the network slice. If admission control for the network slice is successful, it indicates that the count of the number of UEs executed was successful; if admission control for the network slice fails, it indicates that the count of the number of UEs executed failed. The first response message_2 can also carry a failure reason value, which indicates that the UE has other sessions. In step 1015, the first response message_2 can indicate that admission control for the network slice was successful.

[0492] One possible implementation is that NSACF_1 sends an Nnsacf_NumberOfPDUsPerSliceAvailabilityCheckAndUpdate response to SMF+PGW-C_2, with NSACF_1 carrying the result of performing admission control on the network slice in the message it sends.

[0493] Step 1016: Perform the remaining procedures for releasing the PDN connection.

[0494] At this point, the release of PDN connection_1 and PDN connection_2 has been completed.

[0495] As discussed above, in Example 4, regarding the process of determining the number of UEs and sessions triggered by the release of PDN connections, the NSACF, responsible for controlling the number of UEs, also determines whether all PDN connections of the UE should be released when determining the number of UEs corresponding to a network slice. If the UE has no established sessions, the NSACF reduces the number of UEs accessing the network slice identified by S-NSSAI and deletes the UE ID from the context information. This enables network slice admission control in interoperability scenarios.

[0496] It should be noted that, Figure 10 Taking the example of SMF+PGW-C first interacting with NSACF, which is responsible for UE number control, and then interacting with NSACF, which is responsible for session number control, the embodiments of this application are not limited to this. For example, SMF+PGW-C may also first interact with NSACF, which is responsible for session number control, and then interact with NSACF, which is responsible for UE number control.

[0497] The above text combined Figures 4 to 10 The present application provides a detailed description of the method embodiments, which will be discussed below in conjunction with... Figure 11 and Figure 12 The present application describes the device embodiments in detail. It is understood that, in order to achieve the functions described in the above embodiments, Figure 11 or Figure 12The apparatus includes hardware structures and / or software modules corresponding to perform various functions. Those skilled in the art will readily recognize that, based on the units and method steps described in conjunction with the embodiments disclosed in this application, this application can be implemented in hardware or a combination of hardware and computer software. Whether a function is executed in hardware or by computer software driving hardware depends on the specific application scenario and design constraints of the technical solution.

[0498] Figure 11 and Figure 12 The diagram illustrates the possible structures of devices provided in the embodiments of this application. These devices can be used to implement the functions of the first network element, the second network element, the fourth network element, and the NRF in the above method embodiments, and thus can also achieve the beneficial effects of the above method embodiments.

[0499] like Figure 11 As shown, the device 1100 includes a transceiver unit 1110 and a processing unit 1120.

[0500] When device 1100 is used to implement the function of the first network element in the method embodiment:

[0501] Transceiver unit 1120 is configured to obtain first information from a second network element, the first information being used to associate a first session of a user equipment, the first network element supporting control over the number of users accessing the network slice, the first session being associated with the network slice, and the second network element serving the first session; and to receive a first request message from the second network element, the first request message being used to instruct a reduction in the number of users already accessing the network slice. Processing unit 1110 is configured to determine, based on the first information, whether to reduce the number of users already accessing the network slice.

[0502] Optionally, after obtaining the first information, the processing unit 1110 may also save the first information, the network slice, and the corresponding relationship of the user equipment.

[0503] Optionally, the transceiver unit is specifically used to: obtain the first information during the process of the second network element requesting an increase in the number of users already connected to the network slice.

[0504] Optionally, the transceiver unit is specifically configured to: receive a second request message from the second network element when the number of sessions established on the network slice does not exceed the maximum number of sessions allowed to be established on the network slice, wherein the second request message includes the first information.

[0505] Optionally, the processing unit is specifically configured to: if the user equipment establishes a session other than the first session on the network slice, determine to maintain the number of users already connected to the network slice; if the user equipment establishes only the first session on the network slice, determine to reduce the number of users already connected to the network slice.

[0506] Optionally, the processing unit is further configured to: delete the first information after determining whether to reduce the number of users already connected to the network slice.

[0507] Optionally, the first session is a packet data network (PDN) connection established by the user equipment in the evolved packet core (EPC) network.

[0508] When device 1100 is used to implement the function of the second network element in the method embodiment:

[0509] In some implementations, processing unit 1110 is used to determine the network slice associated with the first session of the user equipment; transceiver unit 1120 is used to send first information to a first network element, the first information being used to associate the first session, the first network element supporting control over the number of users accessing the network slice, and a second network element serving the first session; and to send a first request message to the first network element, the first request message being used to instruct a reduction in the number of users already accessing the network slice; wherein, the first information is used to determine whether to reduce the number of users already accessing the network slice.

[0510] Optionally, the transceiver unit 1120 is specifically used to: send the first information to the first network element during the process of requesting an increase in the number of users already connected to the network slice.

[0511] Optionally, the transceiver unit 1120 is specifically configured to: send a second request message to the first network element when the number of sessions established on the network slice does not exceed the maximum number of sessions allowed to be established on the network slice, wherein the second request message includes the first information.

[0512] Optionally, the transceiver unit 1120 is specifically configured to: learn from a third network element that the number of sessions established on the network slice has reached the maximum number of sessions allowed to be established on the network slice, wherein the third network element supports controlling the number of sessions established on the network slice; and after the second network element learns that the number of sessions established on the network slice has reached the maximum number of sessions allowed to be established on the network slice, send the first request message to the first network element.

[0513] Optionally, the transceiver unit 1120 is specifically used to: when the first session is released, the second network element sends the first request message to the first network element.

[0514] Optionally, the first session is a packet data network (PDN) connection established by the user equipment in the evolved packet core (EPC) network.

[0515] In other implementations, processing unit 1110 is configured to determine the network slice associated with the first session of the user equipment; transceiver unit 1120 is configured to send a third request message to a network storage function network element, the third request message being used to request information from a fourth network element, the third request message including the identifier of the network slice and second information, the second information being used to instruct the fourth network element to support control over the number of users accessing the network slice and to support control over the number of sessions established on the network slice; receive a third response message from the network storage function network element, the third response message including information from the fourth network element; and send a fourth request message to the fourth network element, the fourth request message being used to request the fourth network element to control over the number of users accessing the network slice and to control over the number of sessions established on the network slice.

[0516] Optionally, the fourth request message includes the identifier of the user equipment, first information, third information, fourth information, and the identifier of the network slice. The first information is used to associate the first session, wherein: when the user equipment requests to establish the first session, the third information is used to indicate an increase in the number of users already connected to the network slice, and the fourth information is used to indicate an increase in the number of sessions already established in the network slice; when the user equipment requests to release the first session, the third information is used to indicate a decrease in the number of users already connected to the network slice, and the fourth information is used to indicate a decrease in the number of sessions already established in the network slice.

[0517] Optionally, the first information includes at least one of the identifier of the second network element or the identifier of the first session.

[0518] Optionally, the first session is a packet data network (PDN) connection established by the user equipment in the evolved packet core (EPC) network.

[0519] When device 1100 is used to implement the NRF function in the method embodiment:

[0520] The transceiver unit 1120 is configured to receive a third request message from a second network element, the third request message being used to request information from a fourth network element, the third request message including the identifier of the network slice and second information, the second information being used to instruct the fourth network element to support controlling the number of users accessing the network slice and to support controlling the number of sessions established on the network slice; and to send a third response message to the second network element, the third response message including information from the fourth network element.

[0521] When device 1100 is used to implement the function of the fourth network element in the method embodiment:

[0522] The transceiver unit 1120 is configured to receive a fourth request message from a second network element, wherein the fourth network element supports controlling the number of users accessing the network slice and controlling the number of sessions established on the network slice, the second network element serving a first session of a user equipment, the first session being associated with the network slice; the processing unit 1110 is configured to control the number of users accessing the network slice and the number of sessions established on the network slice according to the fourth request message; the transceiver unit 1120 is further configured to send a fourth response message to the second network element, the fourth response message indicating the result of controlling the number of users accessing the network slice and the result of controlling the number of sessions established on the network slice.

[0523] Optionally, the fourth request message includes the identifier of the user equipment, first information, third information, fourth information, and the identifier of the network slice. The first information is used to associate the first session, wherein: when the user equipment requests to establish the first session, the third information is used to indicate an increase in the number of users already connected to the network slice, and the fourth information is used to indicate an increase in the number of sessions already established in the network slice; when the user equipment requests to release the first session, the third information is used to indicate a decrease in the number of users already connected to the network slice, and the fourth information is used to indicate a decrease in the number of sessions already established in the network slice.

[0524] A more detailed description of the processing unit 1110 and the transceiver unit 1120 can be obtained directly from the relevant descriptions in the above method embodiments, and will not be repeated here.

[0525] like Figure 12 As shown, device 1200 includes a processor 1210 and an interface circuit 1220. The processor 1210 and the interface circuit 1220 are coupled to each other. It is understood that the interface circuit 1220 can be a transceiver or an input / output interface. In one implementation, device 1200 may further include a memory 1230 for storing instructions executed by the processor 1210, or storing input data required by the processor 1210 to execute instructions, or storing data generated after the processor 1210 executes instructions.

[0526] When the device 1200 is used to implement the method described above, the processor 1210 is used to implement the function of the processing unit 1120, and the interface circuit 1220 is used to implement the function of the transceiver unit 1110.

[0527] When the aforementioned communication device is a chip applied to the first network element, the chip implements the functions of the first network element in the above method embodiments. The chip receives information from other modules (such as radio frequency modules or antennas) in the first network element, which is sent to the first network element by other devices; or, the chip sends information to other modules (such as radio frequency modules or antennas) in the first network element, which is sent to other devices by the first network element.

[0528] When the aforementioned communication device is a chip applied to the second network element, the chip implements the functions of the second network element in the above method embodiments. The chip receives information from other modules (such as radio frequency modules or antennas) in the second network element, which is sent to the second network element by other devices; or, the chip sends information to other modules (such as radio frequency modules or antennas) in the second network element, which is sent to other devices by the second network element.

[0529] When the aforementioned communication device is a chip that applies a fourth network element, the chip implements the function of the fourth network element in the above method embodiments. The chip receives information from other modules (such as radio frequency modules or antennas) in the fourth network element, which is sent to the fourth network element by other devices; or, the chip sends information to other modules (such as radio frequency modules or antennas) in the fourth network element, which is sent to other devices by the fourth network element.

[0530] When the aforementioned communication device is a chip that applies NRF, the chip implements the NRF functions described in the above method embodiments. The chip receives information from other modules (such as radio frequency modules or antennas) in the NRF, which is information sent to the NRF by other devices; or, the chip sends information to other modules (such as radio frequency modules or antennas) in the NRF, which is information sent to other devices by the NRF.

[0531] This application also provides a chip that acquires and executes instructions to implement the above-described method.

[0532] Alternatively, as one implementation, the chip includes a processor and a data interface, through which the processor reads instructions stored in memory and executes the above method.

[0533] Alternatively, as one implementation, the chip may also include a memory storing instructions, and the processor is used to execute the instructions stored in the memory. When the instructions are executed, the processor is used to perform the methods described above.

[0534] This application also provides a communication system, including any of the above-described communication devices or any of the above-described chips.

[0535] This application also provides a computer-readable storage medium storing instructions for use in the methods described in the above-described method embodiments.

[0536] This application also provides a computer program product containing instructions for implementing the methods described in the above method embodiments.

[0537] It is understood that the processor in the embodiments of this application may be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, transistor logic devices, hardware components, or any combination thereof. A general-purpose processor may be a microprocessor or any conventional processor.

[0538] The memory in the embodiments of this application can be volatile memory or non-volatile memory, or may include both volatile and non-volatile memory. The non-volatile memory can be read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), or flash memory. The volatile memory can be random access memory (RAM), which is used as an external cache. By way of example, but not limitation, many forms of random access memory (RAM) are available, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate synchronous DRAM (DDR SDRAM), enhanced synchronous DRAM (ESDRAM), synchronous linked DRAM (SLDRAM), and direct rambus RAM (DR RAM).

[0539] Those skilled in the art will understand that, for the sake of convenience and brevity, the specific working processes of the systems, devices, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0540] In the various embodiments of this application, unless otherwise specified or in case of logical conflict, the terminology and / or descriptions of different embodiments are consistent and can be referenced by each other. The technical features of different embodiments can be combined to form new embodiments according to their inherent logical relationship.

[0541] In this application, "at least one" means one or more, and "more than one" means two or more. "And / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A alone, A and B simultaneously, or B alone, where A and B can be singular or plural. In the textual description of this application, the character " / " generally indicates an "or" relationship between the preceding and following related objects; in the formulas of this application, the character " / " indicates a "division" relationship between the preceding and following related objects.

[0542] It is understood that the various numerical designations used in the embodiments of this application are merely for descriptive convenience and are not intended to limit the scope of the embodiments of this application. The order of the process numbers described above does not imply the order of execution; the execution order of each process should be determined by its function and internal logic.

[0543] Unless otherwise stated, all technical and scientific terms used in the embodiments of this application have the same meaning as commonly understood by one of ordinary skill in the art. The terminology used in this application is for the purpose of describing specific embodiments only and is not intended to limit the scope of this application. It should be understood that the above are illustrative examples, and the examples above are merely to help those skilled in the art understand the embodiments of this application, and are not intended to limit the embodiments of the application to the specific numerical values ​​or specific scenarios exemplified. Those skilled in the art can obviously make various equivalent modifications or variations based on the examples given above, and such modifications and variations also fall within the scope of the embodiments of this application.

[0544] In the several embodiments provided in this application, it should be understood that the disclosed systems, apparatuses, and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between apparatuses or units may be electrical, mechanical, or other forms.

[0545] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0546] In addition, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit.

[0547] If the aforementioned functions are implemented as software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or a portion of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, a server, or a network device) to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0548] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A network slice admission control method, characterized in that, The method includes: The first network element obtains first information from the second network element. The first information is used to associate a first session of a user equipment. The first network element supports controlling the number of users accessing the network slice. The first session is associated with the network slice. The second network element serves the first session. The first network element receives a first request message from the second network element, the first request message being used to instruct a reduction in the number of users already connected to the network slice; Based on the first information, the first network element determines whether to reduce the number of users already connected to the network slice.

2. The method according to claim 1, characterized in that, The first network element obtains first information from the second network element, including: During the process of the second network element requesting an increase in the number of users already connected to the network slice, the first network element obtains the first information.

3. The method according to claim 1, characterized in that, The first network element obtains first information from the second network element, including: If the number of sessions established on the network slice does not exceed the maximum number of sessions allowed to be established on the network slice, the first network element receives a second request message from the second network element, the second request message including the first information.

4. The method according to any one of claims 1 to 3, characterized in that, The method further includes: The first network element stores the first information.

5. The method according to any one of claims 1 to 3, characterized in that, The first network element determines, based on the first information, whether to reduce the number of users already connected to the network slice, including: If the user equipment establishes a session other than the first session on the network slice, the first network element determines to maintain the number of users who have accessed the network slice. If the user equipment has only established the first session on the network slice, then the first network element determines to reduce the number of users already connected to the network slice.

6. The method according to claim 5, characterized in that, The method further includes: After the first network element determines whether to reduce the number of users already connected to the network slice, the first network element deletes the first information.

7. The method according to any one of claims 1 to 3, characterized in that, The first information includes at least one of the identifier of the second network element or the identifier of the first session.

8. The method according to any one of claims 1 to 3, characterized in that, The first session is a packet data network (PDN) connection established by the user equipment in the evolved packet core (EPC) network.

9. A network slice admission control method, characterized in that, The method includes: The second network element determines the network slice associated with the first session of the user equipment. The second network element sends first information to the first network element. The first information is used to associate the first session. The first network element supports controlling the number of users accessing the network slice. The second network element serves the first session. The second network element sends a first request message to the first network element, the first request message being used to instruct a reduction in the number of users already connected to the network slice; The first information is used to determine whether to reduce the number of users who have accessed the network slice.

10. The method according to claim 9, characterized in that, The second network element sends first information to the first network element, including: During the process of requesting an increase in the number of users already connected to the network slice, the second network element sends the first information to the first network element.

11. The method according to claim 9, characterized in that, The second network element sends first information to the first network element, including: When the number of sessions established on the network slice does not exceed the maximum number of sessions allowed to be established on the network slice, the second network element sends a second request message to the first network element, the second request message including the first information.

12. The method according to claim 10, characterized in that, The method further includes: The second network element learns from the third network element that the number of sessions established on the network slice has reached the maximum number of sessions allowed to be established on the network slice, and the third network element supports controlling the number of sessions established on the network slice; The second network element sends a first request message to the first network element, including: After the second network element learns that the number of sessions established on the network slice has reached the maximum number of sessions allowed to be established on the network slice, the second network element sends the first request message to the first network element.

13. The method according to any one of claims 9 to 11, characterized in that, The second network element sends a first request message to the first network element, including: When releasing the first session, the second network element sends the first request message to the first network element.

14. The method according to any one of claims 9 to 11, characterized in that, The first information includes at least one of the identifier of the second network element or the identifier of the first session.

15. The method according to any one of claims 9 to 11, characterized in that, The first session is a packet data network (PDN) connection established by the user equipment in the evolved packet core (EPC) network.

16. A network slice admission control method, characterized in that, The method includes: The second network element determines the network slice associated with the first session of the user equipment. The second network element sends a third request message to the network storage function network element. The third request message is used to request information from the fourth network element. The third request message includes the identifier of the network slice and second information. The second information is used to instruct the fourth network element to support the control of the number of users accessing the network slice and to support the control of the number of sessions established on the network slice. The second network element receives a third response message from the network storage function network element, the third response message including information about the fourth network element; The second network element sends a fourth request message to the fourth network element. The fourth request message is used to request the fourth network element to control the number of users accessing the network slice and to control the number of sessions established by the network slice.

17. The method according to claim 16, characterized in that, The first session is a packet data network (PDN) connection established by the user equipment in the evolved packet core (EPC) network.

18. A network slice admission control method, characterized in that, The method includes: The network storage function network element receives a third request message from the second network element. The third request message is used to request information from the fourth network element. The third request message includes the identifier of the network slice and second information. The second information is used to instruct the fourth network element to support the control of the number of users accessing the network slice and to support the control of the number of sessions established on the network slice. The network storage function network element sends a third response message to the second network element, the third response message including information about the fourth network element.

19. A communication device, characterized in that, include: A processor for executing computer instructions stored in memory to cause the apparatus to perform the method as claimed in any one of claims 1 to 8, or the method as claimed in any one of claims 9 to 17, or the method as claimed in claim 18.

20. The apparatus according to claim 19, characterized in that, The device also includes the memory for storing the computer instructions.

21. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program that, when executed by one or more processors, causes a device including the processor to perform the method as claimed in any one of claims 1 to 8, or the method as claimed in any one of claims 9 to 17, or the method as claimed in claim 18.

22. A computer program product, characterized in that, The computer program product includes computer program code that, when run on a computer, implements the method as described in any one of claims 1 to 8, or the method as described in any one of claims 9 to 17, or the method as described in claim 18.

23. A communication system, characterized in that, Includes the communication device as described in claim 19 or 20.

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