WO2020155021A1

WO2020155021A1 - Method for session establishment and terminal device

Info

Publication number: WO2020155021A1
Application number: PCT/CN2019/074190
Authority: WO
Inventors: 丁明; 段小嫣; 泮凯翔; 余迪虎
Original assignee: 华为技术有限公司
Priority date: 2019-01-31
Filing date: 2019-01-31
Publication date: 2020-08-06
Also published as: CN112771903A; CN112771903B

Abstract

The present application provides a method for session establishment and a terminal device. The method for session establishment comprises: the terminal device sends a registration request message to an access management function network element, the registration request message being used for requesting registration into a network belonging to a preset public land mobile network (PLMN); the terminal device receives a first message sent by the access management function network element, the first message carrying a first parameter, and the first parameter indicating the maximum number of PDU sessions supported to be established by the terminal device under the preset PLMN; after the terminal device obtains the first parameter, the terminal device can accurately obtain the maximum number of PDU sessions supported to be established by the terminal device per se under the preset PLMN. By means of the technical solution provided in the present application, the terminal device can accurately obtain the maximum number of PDU sessions supported to be established by the terminal device per se under the preset PLMN, thereby improving the performance of the terminal device in establishing the PDU session.

Description

Method and terminal equipment for session establishment

Technical field

This application relates to the field of communications, and more specifically, to a method and terminal device for session establishment.

Background technique

The 5th generation (5G) communication protocol stipulates that the maximum number of packet data unit (PDU) sessions that a terminal device can establish is the maximum number of PDU identifiers (identify, ID) defined by the 5G communication protocol Value, the maximum number of PDU sessions supported by the terminal device under the public land mobile network (PLMN) to which the core network registered by the terminal device belongs, and the maximum number of PDU sessions actually supported by the terminal device, among the three Minimum value.

For the terminal device, the maximum number of PDU session IDs defined by the 5G communication protocol is clear, and the maximum number of PDU sessions actually supported by the terminal device is also clear. However, the maximum number of PDU sessions supported by the terminal device under different PLMNs cannot be accurately known by the terminal device. In the prior art, if the terminal device establishes a PDU session under a PLMN during the establishment of a PDU session, the value of the number of PDU sessions established by the terminal device exceeds the size of the maximum number of PDU sessions supported by the terminal device under the PLMN specified by the operator. The network device sends an indication message to the terminal device to indicate that the maximum number of PDU sessions supported by the terminal device under the PLMN has been reached.

Since multiple PDU sessions can be established in a 5G system at the same time, in some cases, it may happen that when a network device sends the above-mentioned indication information, the maximum number of PDU sessions supported by the terminal device has not been reached, which causes the terminal device to determine The value of the number of PDU sessions established under a certain PLMN is inaccurate, which further affects the terminal device to determine the maximum number of PDU sessions that it can establish. Therefore, how the terminal device accurately learns the number of PDU sessions that can be established under a certain PLMN to establish PDU sessions has become an urgent problem to be solved.

Summary of the invention

This application provides a method and terminal device for session establishment. The terminal device indicates the maximum number of packet data unit PDU sessions that the terminal device supports to establish under a preset PLMN by receiving an access management function network element sent by the terminal device. It can accurately know the value of the number of PDU sessions established under a certain PLMN.

In a first aspect, a method for session establishment is provided, including: a terminal device sends a registration request message to the network side, the registration request message is used to request registration to a network belonging to a preset public land mobile communication network PLMN; The device receives the first message sent by the access management function network element, where the first message carries the first parameter, and the first parameter indicates the maximum number of packet data unit PDU sessions established by the terminal device under the preset PLMN.

According to the method for session establishment provided by the embodiments of this application, when the terminal device is registered to the core network belonging to the preset public land mobile communication network PLMN, the access management function network element on the core network side will indicate the preset The first parameter of the maximum number of packet data unit PDU sessions that the terminal device under the PLMN supports to establish is carried in the first message and notified to the terminal device. Furthermore, after receiving the first message, the terminal device can accurately learn the maximum number of packet data unit PDU sessions that it supports under the preset PLMN to which the registered core network belongs.

It should be understood that the foregoing indication information indicating the maximum number of packet data unit PDU sessions that can be established by the terminal device under the preset PLMN is called the first parameter, which is only an example and does not constitute any limitation on the protection scope of this application. The indication information indicating the maximum number of packet data unit PDU sessions supported by the terminal device under the preset PLMN are all within the protection scope of this application. For example, the first parameter may also be called first information, information element, and so on.

It should also be understood that the above-mentioned calling the message carrying the first parameter the first message is only an example, and cannot constitute any limit to the protection scope of this application. Any message that can carry the first parameter falls within the protection scope of this application. within. For example, the first message may be the signaling between the terminal device and the access management function network element in the flow of the existing communication method, or the first message may also be added for notifying the terminal device of the first parameter. The signaling between the terminal equipment and the access management function network element.

With reference to the first aspect, in some implementations of the first aspect, the above-mentioned first parameter is a preset value of the maximum number of PDU sessions allowed to be established by the terminal device under the PLMN, and the terminal device sets the first parameter and the PDU session defined by the protocol The minimum value of the number of identifiers and the maximum number of PDU sessions actually supported by the terminal device is determined as the maximum number of PDU sessions that the terminal device is allowed to establish; the method for session establishment provided in this application also includes: The maximum number of PDU sessions to establish a PDU session.

According to the method for session establishment provided by the embodiments of the present application, after the terminal device receives the above-mentioned first parameter, it can be determined based on the first parameter, the number of PDU session identifiers defined by the protocol, and the maximum number of PDU sessions actually supported by the terminal device The maximum number of PDU sessions allowed by itself. And in the subsequent process of establishing a PDU session, the PDU session is established according to the maximum number of PDU sessions allowed to be established by itself. Since the terminal device can know the maximum number of PDU sessions that it is allowed to establish, it can clarify the number of PDU sessions that it can establish during the process of establishing a PDU session. There is no need to initiate blindly when the number of PDU sessions that it can establish cannot be accurately known. PDU session establishment request, thereby improving the performance of establishing PDU session.

It should be understood that the aforementioned terminal device can determine the maximum number of PDU sessions that it allows to establish based on the first parameter, the number of PDU session identifiers defined by the protocol, and the maximum number of PDU sessions actually supported by the terminal device. This is because the first parameter indicates the maximum number of PDU sessions supported by the terminal device under the preset PLMN, and when the terminal device determines the maximum number of PDU sessions allowed to be established by itself, it is the maximum number of PDU sessions supported by the terminal device under the preset PLMN. The minimum of the number of PDU sessions, the number of PDU session identifiers defined by the protocol, and the maximum number of PDU sessions actually supported by the terminal device is determined as the maximum number of PDU sessions allowed to be established by itself. Therefore, after receiving the first parameter, the terminal device can accurately determine the maximum number of PDU sessions supported by the terminal device under the preset PLMN. The number of PDU session identifiers defined by the protocol and the maximum number of PDU sessions actually supported by the terminal device are The value known in advance by the terminal device, and then the method for session establishment provided by the embodiment of this application, informs the terminal device of the preset maximum number of PDU sessions established by the terminal device under the PLMN through the first parameter, so that the terminal device can clearly determine The maximum number of PDU sessions allowed by itself.

In combination with the first aspect and the foregoing implementation manners, in another implementation manner of the first aspect, the terminal device establishes a PDU session according to the maximum number of PDU sessions that the terminal device allows to establish, including: when the terminal device has established the number of PDU sessions When the number is equal to the maximum number of PDU sessions allowed to be established by the terminal device, the terminal device refuses to establish a PDU session, or the terminal device establishes a PDU session after releasing any of the established PDU sessions.

According to the method for session establishment provided by the embodiments of the present application, in the process of establishing a PDU session, the terminal device has already clarified the maximum number of PDU sessions allowed to be established by itself, so when initiating the establishment of a PDU session, the terminal device has already established When the number of PDU sessions is equal to the maximum number of PDU sessions allowed to be established by itself, the terminal device does not need to blindly initiate the next PDU session establishment request like the existing PDU session establishment method. It is possible to refuse to establish the next PDU session, or to release one PDU session in an already established PDU session, so that the next PDU session can be successfully established. Further improve the performance of establishing PDU sessions.

It should be understood that the foregoing release of an established PDU session should avoid releasing an emergency service PDU session, or a service PDU session with a higher priority.

With reference to the first aspect and the foregoing implementation manners, in another implementation manner of the first aspect, the first message is a registration reception message, and the registration reception message is used to indicate that the terminal device is successfully registered.

According to the method for establishing a session provided by the embodiment of the present application, the above-mentioned first message may be a registration reception message received in the registration process of the terminal device. That is to say, in the method for session establishment provided by the embodiment of this application, the message carrying the first parameter sent by the access management function network element to the terminal device may be the reuse of the access management in the existing terminal device registration process The functional network element needs to send the registration reception message to the terminal device without adding new interactive signaling to reduce resource overhead.

It should be understood that when the first parameter is carried in the registration reception message to notify the terminal device, the first parameter is equivalent to a newly added information element in the registration reception message. In this application, the information that should be carried in the registration reception message in the prior art will not be repeated. Specifically, when the first parameter is carried in the registration reception message, the message load of the registration reception message is increased.

In combination with the first aspect and the foregoing implementation manners, in another implementation manner of the first aspect, before the terminal device sends the registration request message to the access management function network element, the method for session establishment provided in the embodiment of the present application is It also includes: the terminal device switches from the first communication system to the second communication system, wherein the number of PDU sessions established by the terminal device in the first communication system is M, and M is a positive integer.

The method for establishing a session according to the embodiments of the present application can be applied to a scenario where a terminal device has a different system handover. It can be understood that the terminal device may be from the first communication system before the second communication system initiates the registration request message. Switched to the second communication system, and the terminal device in the first communication system can also establish a PDU session. That is to say, the method for session establishment provided by the embodiment of the present application can be applied to the scenario of switching between different systems, and the application scope of the method for session establishment provided by the embodiment of the present application is improved.

It should be understood that the above-mentioned first communication system and second communication system are only examples of different communication systems, and do not limit the protection scope of the present application.

In combination with the first aspect and the foregoing implementation manners of the first aspect, in another implementation manner of the first aspect, the method for establishing a session provided in an embodiment of the present application further includes: there is a difference between the first communication system and the second communication system. When the system switches the interface, the registration request message carries the first status indication information, the first status indication information is used to indicate the status after the M-channel PDU session is transferred to the second communication system; the registration reception message carries the second status indication information, The second state indication information is used to indicate the N PDU sessions in the active state among the M PDU sessions, and N is a positive integer less than or equal to M; the terminal device determines that the N PDU sessions are in the active state according to the second state indication information.

According to the method for session establishment provided by the embodiments of the present application, if the terminal device is switched from the first communication system to the second communication system, there is a different system switching interface between the first communication system and the second communication system. Then the PDU session established by the terminal device in the first communication system can be directly transferred to the second communication system through the different system switching interface. That is to say, for the PDU session established by the terminal device in the first communication system, the terminal device does not need to In the second communication system, the PDU session establishment process is initiated again. However, when the terminal device initiates the registration process in the second communication system, it needs to notify the access management function network in the second communication system of the status information of the multiple PDU session transferred from the first communication system to the second communication system. yuan. After the access management function network element learns the status of the multiple PDU session, it determines which PDU sessions in the multiple PDU session can be in the second communication system according to the maximum number of PDU sessions that the terminal device supports under the preset PLMN. In the active state, the terminal device is notified of the PDU session information that can be in the active state in the second communication system. After the terminal device is switched between the different systems, it is clear that the active PDU session among the multiple PDU sessions transferred from the first communication system to the second communication system is the existence between the first communication system and the second communication system. The different system switches the interface, and the terminal device switches from the first communication system to the second communication system to provide a solution for PDU session establishment. In combination with the first aspect and the foregoing implementation manners, in another implementation manner of the first aspect, the first message is a PDU session establishment rejection message, and the PDU session establishment rejection message is used to refuse to establish a PDU session. The embodiment of this application provides The method for session establishment further includes: the terminal device sends at least one PDU session establishment request message to the access management function network element.

According to the method for session establishment provided in the embodiment of the present application, the above-mentioned first message may be a PDU session establishment rejection message received in the process of establishing a PDU session by the terminal device. That is to say, in the method for session establishment provided by the embodiment of this application, the message carrying the first parameter sent by the access management function network element to the terminal device may be the connection in the process of establishing a PDU session by the existing terminal device. The PDU session establishment rejection message that the access management function network element may send to the terminal device can reduce resource overhead without adding new interactive signaling.

In combination with the first aspect and the foregoing implementation manners, in another implementation manner of the first aspect, the PDU session establishment rejection message includes: the downlink non-access layer direct transmission rejection 5G large-scale multiple input multiple output 5GMM reason code #65.

According to the method for session establishment provided by the embodiments of this application, the aforementioned PDU session establishment rejection message may be an existing one used to indicate that the maximum number of PDU sessions has reached, and the downlink non-access layer direct transmission rejects 5G large-scale multi-input Multiple output 5GMM reason code #65.

With reference to the first aspect and the foregoing implementation manners of the first aspect, in another implementation manner of the first aspect, the method for establishing a session provided in an embodiment of the present application further includes: a terminal device receives an update message sent by an access management network element, The update message carries the second parameter, and the second parameter is the parameter after the first parameter changes.

According to the method for session establishment provided by the embodiment of the present application, when the maximum number of PDU sessions supported by the terminal device under the preset PLMN changes, that is to say, the terminal device under the preset PLMN is used to indicate When the first parameter that supports the maximum number of PDU sessions to be established is changed to the second parameter. The access management network element can notify the terminal device through an update message, so that the terminal device can timely know the change of the maximum number of PDU sessions that the terminal device supports under the preset PLMN, and then accurately and timely determine the maximum number of PDU sessions that it allows to establish. The accuracy of the terminal device in determining the maximum number of PDU sessions established by the terminal device under the preset PLMN can be improved.

Combining the first aspect and the foregoing implementation manners, in another implementation manner of the first aspect, the preset maximum number of PDU sessions supported by the terminal device under the PLMN is customized for the terminal device by the operator according to the contract data of the terminal device of.

According to the method for session establishment provided by the embodiments of this application, the preset maximum number of PDU sessions supported by the terminal device under the PLMN can be customized by the operator for the terminal device according to the contract data of the terminal device, that is to say The embodiment of the present application proposes a possible solution that can specifically determine the maximum number of PDU sessions established by the terminal device under the PLMN for different PLMNs of different terminal devices.

In a second aspect, a method for session establishment is provided, which is characterized in that it includes: an access management function network element receives a registration request message sent by a terminal device, and the registration request message is used for the terminal device to request registration to a preset In the network of the public land mobile communication network PLMN; the access management function network element determines the first parameter, and the first parameter indicates the maximum number of packet data unit PDU sessions that the terminal device supports under the preset PLMN; the access management function network element The first parameter is saved; the access management function network element sends a first message to the terminal device, and the first message carries the first parameter.

According to the method for session establishment provided by the embodiments of the present application, when a terminal device requests to register to a core network belonging to a preset public land mobile communication network PLMN, the access management function network element on the core network side will indicate the preset It is assumed that the first parameter of the maximum number of packet data unit PDU sessions that the terminal device under the PLMN supports to establish is carried in the first message and notified to the terminal device, and the local access management function network element in the access management function network element will The first parameter is saved. Furthermore, after receiving the first message, the terminal device can accurately learn the maximum number of packet data unit PDU sessions that it supports under the preset PLMN to which the registered core network belongs.

With reference to the second aspect and the foregoing implementation manners, in another implementation manner of the second aspect, the first message is a registration reception message, and the registration reception message is used to indicate that the terminal device is successfully registered.

According to the method for session establishment provided by the embodiment of the present application, the above-mentioned first message may be a registration reception message sent by the access management function network element to the terminal device in the terminal device registration process. That is to say, in the method for session establishment provided by the embodiment of this application, the message carrying the first parameter sent by the access management function network element to the terminal device may be the reuse of the access management in the existing terminal device registration process The functional network element needs to send the registration reception message to the terminal device without adding new interactive signaling to reduce resource overhead.

In combination with the second aspect and the foregoing implementation manners of the second aspect, in another implementation manner of the second aspect, the registration request message carries first status indication information, and the first status indication information is used to indicate the status of the M-channel PDU session, where: The M-channel PDU session is the number of PDU sessions established by the terminal device in the first communication system and transferred to the second communication system when the terminal device switches from the first communication system to the second communication system; this embodiment provides The method for session establishment further includes: the access management function network element determines the active N PDU sessions in the M PDU session according to the first parameter; the registration reception message carries the second state indication information and the second state indication information Used for N-way PDU sessions, M is a positive integer, and N is a positive integer less than or equal to M.

According to the method for session establishment provided by the embodiments of the present application, if the terminal device is switched from the first communication system to the second communication system, there is a different system switching interface between the first communication system and the second communication system. Then the PDU session established by the terminal device in the first communication system can be directly transferred to the second communication system through the different system switching interface. That is to say, for the PDU session established by the terminal device in the first communication system, the terminal device does not need to In the second communication system, the PDU session establishment process is initiated again. However, when the terminal device initiates the registration process in the second communication system, it needs to notify the access management function network in the second communication system of the status information of the multiple PDU session transferred from the first communication system to the second communication system. yuan. After the access management function network element learns the status of the multiple PDU session, it determines which PDU sessions in the multiple PDU session can be in the second communication system according to the maximum number of PDU sessions that the terminal device supports under the preset PLMN. In the active state, the terminal device is notified of the PDU session information that can be in the active state in the second communication system. After the terminal device is switched between the different systems, it is clear that the active PDU session among the multiple PDU sessions transferred from the first communication system to the second communication system is the existence between the first communication system and the second communication system. The different system switches the interface, and the terminal device switches from the first communication system to the second communication system to provide a solution for PDU session establishment.

In combination with the second aspect and the foregoing implementation manners of the second aspect, in another implementation manner of the second aspect, the first message is a PDU session establishment rejection message, the PDU session establishment rejection message is used to refuse to establish a PDU session, and the method further includes: access The management function network element receives at least one PDU session establishment request message sent by the terminal device.

According to the method for session establishment provided by the embodiment of the present application, the above-mentioned first message may be a PDU session establishment rejection message sent by the access management function network element to the terminal device in the process of establishing a PDU session by the terminal device. That is to say, in the method for session establishment provided by the embodiment of this application, the message carrying the first parameter sent by the access management function network element to the terminal device may be the connection in the process of establishing a PDU session by the existing terminal device. The PDU session establishment rejection message that the access management function network element may send to the terminal device can reduce resource overhead without adding new interactive signaling.

In combination with the second aspect and the foregoing implementation manners, in another implementation manner of the second aspect, the PDU session establishment rejection message includes: the downlink non-access layer direct transmission rejects 5G large-scale multiple input multiple output 5GMM reason code #65.

With reference to the second aspect and the foregoing implementation manners, in another implementation manner of the second aspect, the access management function network element determining the first parameter includes: the access management function network element sends a query message to the data management network element to query The message is used to query the first parameter; the access management function network element receives a feedback message sent by the data management network element, and the feedback message includes the first parameter; or the access management function network element determines the first parameter based on a local policy.

According to the method for session establishment provided by the embodiment of the present application, the first parameter determined by the access management function network element may be obtained by querying the data management network element, or may be determined according to the local policy of the access management function network element. Different solutions are provided for the access management function network element to determine the first parameter, so that the access management function network element can flexibly select a solution capable of determining the first parameter according to different situations.

In combination with the second aspect and the foregoing implementation manners, in another implementation manner of the second aspect, the query message is an access authentication message; the feedback message is the subscription data of the terminal device.

According to the method for session establishment provided by the embodiment of the present application, the process of the access management function network element querying the data management network element to obtain the first parameter may be implemented in the existing access authentication process. That is, it is possible to reuse the existing interactive signaling between the access management function network element and the data management network element, saving resource overhead.

With reference to the second aspect and the foregoing implementation manners, in another implementation manner of the second aspect, the method further includes: the access management network element sends an update message to the terminal device, the update message carries a second parameter, and the second parameter is The parameter after the first parameter has changed.

In combination with the second aspect and the foregoing implementation manners, in another implementation manner of the second aspect, the preset maximum number of PDU sessions supported by the terminal device under the PLMN is customized for the terminal device by the operator according to the contract data of the terminal device of.

In a third aspect, a method for session establishment is provided, which is characterized in that it includes: a data management network element receiving a query message sent by an access management function network element, the query message is used to query a first parameter, and the first parameter indicates The preset maximum number of packet data unit PDU sessions established by the terminal equipment under the public land mobile communication network PLMN; the data management network element sends a feedback message to the access management function network element, and the feedback message carries the first parameter.

According to the method for session establishment provided by the embodiments of the present application, after receiving the query message sent by the access management function network element, the data management network element can indicate the maximum number of PDU sessions that the terminal device under the preset PLMN supports to establish The first parameter is carried in the feedback message and notified to the access management function network element, that is, in the embodiment of this application, it is clear that the data management network element can realize the notification that the access management function network element can realize the maximum supported establishment of terminal equipment under the PLMN preset by the access management function network element. The function of the number of PDU sessions.

In combination with the third aspect and the foregoing implementation manners, in another implementation manner of the third aspect, the query message is an access authentication message; the feedback message is subscription data of the terminal device.

According to the method for session establishment provided by the embodiment of the present application, the process of the data management network element feeding back the first parameter to the access management function network element may be implemented in the existing access authentication process. That is, it is possible to reuse the existing interactive signaling between the access management function network element and the data management network element, saving resource overhead.

In combination with the third aspect and the foregoing implementation manners, in another implementation manner of the third aspect, the preset maximum number of PDU sessions supported by the terminal device under the PLMN is customized for the terminal device by the operator according to the contract data of the terminal device of.

In a fourth aspect, a terminal device is provided, including: one or more processors; memory; multiple application programs; and one or more programs, wherein one or more programs are stored in the memory, and when one or more When each program is executed by the processor, the terminal device is caused to perform the following steps: send a registration request message to the access management function network element, the registration request message is used to request registration to a network belonging to the preset public land mobile communication network PLMN Receiving a first message sent by the access management function network element, the first message carrying a first parameter, the first parameter indicating the maximum packet data that the terminal device supports to establish under the preset PLMN The number of unit PDU sessions. In a fifth aspect, a terminal device is provided. The terminal device includes a processor and a transceiver. Among them, the processor and the transceiver communicate with each other through an internal connection path.

With reference to the fourth aspect and the foregoing implementation manners, in another implementation manner of the fourth aspect, when the one or more programs are executed by the processor, the terminal device is caused to execute the following steps: The first parameter, the value of the number of PDU session identifiers defined by the protocol and the value of the maximum number of PDU sessions actually supported by the terminal device are determined as the maximum number of PDU sessions allowed to be established by the terminal device; according to the maximum number of PDU sessions allowed to be established by the terminal device Quantity, establish PDU session.

With reference to the fourth aspect and the foregoing implementation manners, in another implementation manner of the fourth aspect, establishing a PDU session according to the maximum number of PDU sessions allowed to be established by the terminal device includes: when the terminal device has established a PDU session When the number is equal to the maximum number of PDU sessions allowed to be established by the terminal device, the terminal device refuses to establish the PDU session, or the terminal device releases any of the established PDU sessions and then establishes all PDU sessions. The PDU session.

With reference to the fourth aspect and the foregoing implementation manners thereof, in another implementation manner of the fourth aspect, the first message is a registration reception message, and the registration reception message is used to indicate that the terminal device is successfully registered.

With reference to the fourth aspect and the foregoing implementation manners, in another implementation manner of the fourth aspect, before sending a registration request message to the access management function network element, when the one or more programs are processed by the When the device is executed, the terminal device is caused to perform the following steps: switching from the first communication system to the second communication system, wherein the number of PDU sessions established by the terminal device in the first communication system is M, and M is Positive integer.

With reference to the fourth aspect and the foregoing implementation manners, in another implementation manner of the fourth aspect, when a different system switching interface exists between the first communication system and the second communication system, the registration request message Carrying first status indication information, the first status indication information is used to indicate the status of the M-way PDU session after it is transferred to the second communication system; the registration reception message carries second status indication information, the second The status indication information is used to indicate the active N PDU sessions in the M PDU session, where N is a positive integer less than or equal to M; when the one or more programs are executed by the processor, all The terminal device performs the following steps: the terminal device determines that the N-way PDU session is in an active state according to the second state indication information.

With reference to the fourth aspect and the foregoing implementation manners, in another implementation manner of the fourth aspect, when there is no different system switching interface between the first communication system and the second communication system, when the one or When multiple programs are executed by the processor, the terminal device is caused to perform the following steps: according to the maximum number of PDU sessions allowed to be established by the terminal device, it is determined that the M-channel PDU session can be used in the second communication system For the established N PDU sessions, the N is a positive integer less than or equal to M.

With reference to the fourth aspect and the foregoing implementation manners, in another implementation manner of the fourth aspect, the first message is a PDU session establishment rejection message, and the PDU session establishment rejection message is used to refuse to establish a PDU session. When the one or more programs are executed by the processor, the terminal device is caused to perform the following steps: send at least one PDU session establishment request message to the access management function network element.

With reference to the fourth aspect and the foregoing implementation manners thereof, in another implementation manner of the fourth aspect, when the one or more programs are executed by the processor, the terminal device is caused to perform the following steps: receiving the An update message sent by an access management network element, where the update message carries a second parameter, and the second parameter is a parameter after the first parameter changes.

In combination with the fourth aspect and the foregoing implementation manners, in another implementation manner of the fourth aspect, the preset maximum number of PDU sessions supported by the terminal device under the PLMN is customized for the terminal device by the operator according to the contract data of the terminal device of.

In a fifth aspect, a computer-readable storage medium is provided, on which a computer program is stored, and when the program is executed by a processor, the method in the first aspect or any of the possible implementation manners of the first aspect is implemented.

In a sixth aspect, a computer program product is provided. The computer program product includes: computer program code. When the computer program code is executed by the communication unit, processing unit or transceiver, or processor of a terminal device, the terminal device executes the foregoing The first method.

In a seventh aspect, a chip system is provided, including a processor, configured to support a terminal device to implement the method of the first aspect.

In an eighth aspect, an access management function network element is provided, including: one or more processors; a memory; multiple application programs; and one or more programs, wherein one or more programs are stored in the memory, when When one or more programs are executed by the processor, the access management function network element causes the access management function network element to perform the following steps: receiving a registration request message sent by a terminal device, where the registration request message is used by the terminal device to request registration to a preset public In the network of the land mobile communication network PLMN; determine a first parameter, the first parameter indicating the maximum number of packet data unit PDU sessions that the terminal device supports to establish under the preset PLMN; save the first parameter; Send a first message to the terminal device, where the first message carries the first parameter.

With reference to the eighth aspect and the foregoing implementation manners, in another implementation manner of the eighth aspect, the first message is a registration reception message, and the registration reception message is used to indicate that the terminal device is successfully registered.

With reference to the eighth aspect and the foregoing implementation manners, in another implementation manner of the eighth aspect, the registration request message carries first status indication information, and the first status indication information is used to indicate the status of the M-channel PDU session, where: M-channel PDU session refers to the number of PDU sessions established by the terminal device in the first communication system and transferred to the second communication system when the terminal device switches from the first communication system to the second communication system; when one or more programs When executed by the processor, the access management function network element is caused to perform the following steps: determine the active N PDU session in the M PDU session according to the first parameter; the registration reception message carries the second state indication information, the second state The indication information is used for N PDU sessions, M is a positive integer, and N is a positive integer less than or equal to M.

In combination with the eighth aspect and the foregoing implementation manners, in another implementation manner of the eighth aspect, the first message is a PDU session establishment rejection message, and the PDU session establishment rejection message is used to refuse to establish a PDU session, when one or more programs When executed by the processor, the access management function network element is caused to perform the following steps: receiving at least one PDU session establishment request message sent by the terminal device.

With reference to the eighth aspect and the foregoing implementation manners, in another implementation manner of the eighth aspect, the PDU session establishment rejection message includes: the downlink non-access layer direct transmission rejects 5G large-scale multiple input multiple output 5GMM reason code #65.

With reference to the eighth aspect and the foregoing implementation manners of the eighth aspect, in another implementation manner of the eighth aspect, determining the first parameter includes: sending a query message to a data management network element, where the query message is used to query the first parameter; and receiving the data management network The feedback message sent by the meta, the feedback message includes the first parameter; or the first parameter is determined based on a local policy.

With reference to the eighth aspect and the foregoing implementation manners, in another implementation manner of the eighth aspect, the query message is an access authentication message; the feedback message is the subscription data of the terminal device.

With reference to the eighth aspect and the foregoing implementation manners, in another implementation manner of the eighth aspect, when one or more programs are executed by the processor, the access management function network element is caused to perform the following steps: send an update to the terminal device Message, the update message carries the second parameter, and the second parameter is the parameter after the first parameter changes.

In combination with the eighth aspect and the foregoing implementation manners, in another implementation manner of the eighth aspect, the preset maximum number of PDU sessions supported by the terminal device under the PLMN is customized for the terminal device by the operator according to the contract data of the terminal device of.

In a ninth aspect, a computer-readable storage medium is provided, on which a computer program is stored, and when the program is executed by a processor, the second aspect or the method in the possible implementation manner of any aspect of the second aspect is implemented.

In a tenth aspect, a computer program product is provided, the computer program product includes: computer program code, when the computer program code is applied to a communication unit, a processing unit or a transceiver, or a processor of a network element to make the access management The functional network element executes the method of the second aspect described above.

In an eleventh aspect, a chip system is provided, including a processor, configured to support an access management function network element to implement the method of the second aspect.

In a twelfth aspect, a data management network element is provided, including: one or more processors; a memory; multiple application programs; and one or more programs, wherein one or more programs are stored in the memory, and when a Or when multiple programs are executed by the processor, the access management function network element is caused to perform the following steps: receiving a query message sent by the access management function network element, the query message is used to query the first parameter, and the first parameter indicates a preset public The maximum number of packet data unit PDU sessions that the terminal device under the land mobile communication network PLMN supports; sends a feedback message to the access management function network element, and the feedback message carries the first parameter.

In combination with the twelfth aspect and the foregoing implementation manners, in another implementation manner of the twelfth aspect, the query message is an access authentication message; the feedback message is the subscription data of the terminal device.

In combination with the twelfth aspect and the foregoing implementation manners, in another implementation manner of the twelfth aspect, the preset maximum number of PDU sessions supported by the terminal device under the PLMN is the operator based on the terminal device's contract data, which is the terminal Equipment customized.

In a thirteenth aspect, a computer-readable storage medium is provided, on which a computer program is stored, and the program is executed by a processor to implement the third aspect or the method in the possible implementation manners of any aspect of the third aspect.

In a fourteenth aspect, a computer program product is provided. The computer program product includes: computer program code, when the computer program code is run by the communication unit, processing unit or transceiver, or processor of the applied network element, the data management The network element executes the method of the third aspect described above.

In a fifteenth aspect, a chip system is provided, including a processor, configured to support a data management network element to implement the method of the third aspect.

In a sixteenth aspect, a communication system is provided, which includes one or more of the aforementioned terminal equipment, access management function network element, and data management network element.

In a possible design, the communication system may also include other devices that interact with terminal devices, access management function network elements, and data management network elements in the solution provided in the embodiments of the present application, and so on.

Exemplarily, implementing the foregoing method for session establishment in the communication system includes:

The terminal device sends a registration request message to the access management function network element, where the registration request message is used to request registration to a network belonging to the preset public land mobile communication network PLMN, where the access management function network element is sent to the network Core network equipment in

After the access management function network element receives the registration request message sent by the terminal device, it queries the data management network element for the maximum number of packet data unit PDU sessions supported by the terminal device under the preset PLMN; or, After the access management function network element receives the registration request message sent by the terminal device, it determines the maximum number of PDU sessions that the terminal device supports to establish under the preset PLMN according to a local policy;

After the access management function network element determines the maximum number of PDU sessions supported by the terminal device under the preset PLMN, the access management function network element downloads the terminal device to the preset PLMN The maximum number of PDU sessions that can be established is saved locally;

Further, the access management function network element carries the first parameter that can indicate the maximum number of PDU sessions that the terminal device supports to establish under the preset PLMN in a registration reception message and sends it to the terminal device;

After receiving the first parameter, the terminal device determines the maximum number of PDU sessions allowed to be established by the terminal device based on the first parameter, the number of PDU session identifiers defined by the protocol, and the maximum number of PDU sessions actually supported by the terminal device;

The terminal device can establish a PDU session according to the determined maximum number of PDU sessions allowed to be established by the terminal device.

The method and terminal device for session establishment provided by the embodiments of the present application are used to indicate the maximum number of packet data unit PDU sessions established by the terminal device under the preset PLMN sent by the access management function network element , Can accurately know the value of the number of PDU sessions established under a certain PLMN.

Description of the drawings

FIG. 1 is a system architecture diagram applicable to an embodiment of the application;

FIG. 2 is a flowchart of registration of a terminal device according to an embodiment of the present application;

FIG. 3 is a schematic flowchart of a method for session establishment according to an embodiment of the present application;

FIG. 4 is a schematic flowchart of a method for updating a first parameter according to an embodiment of the present application;

FIG. 5 is a schematic flowchart of another method for updating a first parameter according to an embodiment of the present application;

FIG. 6 is a schematic diagram of a session establishment provided by an embodiment of the present application;

FIG. 7 is a schematic diagram of a registration receiving message provided by an embodiment of the present application;

FIG. 8 is a schematic diagram of another session establishment provided by an embodiment of the present application;

FIG. 9 is a schematic diagram of another session establishment provided by an embodiment of the present application. ；

FIG. 10 is a schematic diagram of yet another session establishment provided by an embodiment of the present application;

FIG. 11 is a schematic diagram of the terminal device 10 proposed in this application;

FIG. 12 is a schematic structural diagram of a terminal device 20 applicable to an embodiment of the present application;

FIG. 13 is a schematic block diagram of an access management function network element 100 provided by an embodiment of the present application;

FIG. 14 is a schematic block diagram of a data management network element 200 provided by an embodiment of the present application.

detailed description

The technical solution in this application will be described below in conjunction with the drawings.

Figure 1 is a network architecture applied to an embodiment of the present application. As shown in Figure 1, the various parts involved in the network architecture are described below.

1. Terminal device 110: It can include various handheld devices with wireless communication functions, vehicle-mounted devices, wearable devices, computing devices or other processing devices connected to wireless modems, as well as various forms of terminals, mobile stations, MS), terminal (terminal), user equipment (UE), soft terminal, etc. For example, water meters, electricity meters, sensors, etc.

2. (Radio access network, (R)AN) network element 120: used to provide network access functions for authorized terminal equipment in a specific area, and can use different qualities according to the level of terminal equipment and service requirements Transmission tunnel.

(R)AN network elements can manage wireless resources, provide access services for terminal devices, and then complete the forwarding of control signals and terminal device data between the terminal devices and the core network. (R)AN network elements can also be understood as traditional networks Base station in.

3. User plane network element 130: used for packet routing and forwarding and quality of service (QoS) processing of user plane data, etc.

In a 5G communication system, the user plane network element may be a user plane function (UPF) network element. In the future communication system, the user plane network element can still be a UPF network element, or it can have other names, which is not limited by this application.

4. Data network element 140: used to provide a network for transmitting data.

In a 5G communication system, the data network element may be a data network (DN) network element. In the future communication system, the data network network element may still be a DN network element, or may also have other names, which is not limited in this application.

5. Access management network element 150: Mainly used for mobility management and access management, etc., and can be used to implement other functions other than session management in the mobility management entity (mobility management entity, MME) function, for example, legal Monitoring and access authorization/authentication functions.

In a 5G communication system, the access management network element may be an access management function (access and mobility management function, AMF) network element. In the future communication system, the access management network element may still be an AMF network element, or may also have other names, which is not limited in this application.

6. Session management network element 160: Mainly used for session management, terminal equipment Internet Protocol (IP) address allocation and management, selection of end points that can manage user plane functions, policy control and charging function interfaces, and downlink Data notification, etc.

In a 5G communication system, the session management network element may be a session management function (session management function, SMF) network element. In the future communication system, the session management network element may still be an SMF network element, or may also have other names, which are not limited by this application.

7. Policy control network element 170: a unified policy framework used to guide network behavior, and provide policy rule information for control plane function network elements (such as AMF, SMF network elements, etc.).

In a 4G communication system, the policy control network element may be a policy and charging rules function (PCRF) network element. In a 5G communication system, the policy control network element may be a policy control function (PCF) network element. In the future communication system, the policy control network element may still be a PCF network element, or may also have other names, which is not limited in this application.

8. Authentication server 180: used for authentication services, generating keys to implement two-way authentication for terminal devices, and supporting a unified authentication framework.

In a 5G communication system, the authentication server may be an authentication server function (authentication server function, AUSF) network element. In the future communication system, the authentication server function network element may still be an AUSF network element, or may also have other names, which is not limited by this application.

9. Data management network element 190: used to process terminal device identification, access authentication, registration, and mobility management.

In a 5G communication system, the data management network element may be a unified data management (UDM) network element; in a 4G communication system, the data management network element may be a home subscriber server (HSS) network In the future communication system, the unified data management can still be a UDM network element, or it can have other names, which is not limited in this application.

10. Application network element 1100: used for data routing affected by applications, access to network open function network elements, and interaction with the policy framework for policy control.

In a 5G communication system, the application network element may be an application function (AF) network element. In the future communication system, the application network element may still be an AF network element, or may also have other names, which is not limited by this application.

11. Network storage network element: used to maintain real-time information of all network functions and services in the network.

In a 5G communication system, the network storage network element may be a network repository function (NRF) network element. In the future communication system, the network storage network element may still be an NRF network element, or may also have other names, which are not limited by this application.

It is understandable that the aforementioned network elements or functions may be network elements in hardware devices, software functions running on dedicated hardware, or virtualization functions instantiated on a platform (for example, a cloud platform). For the convenience of description, in the follow-up of this application, the access management network element is the AMF network element, the data management network element is the UDM network element, the session management network element is the SMF network element, and the user plane network element is the UPF network element.

Further, the AMF network element is abbreviated as AMF, the UDM network element is abbreviated as UDM, the SMF network element is abbreviated as SMF, and the UPF network element is abbreviated as UPF. That is, the AMF described later in this application can be replaced with access management network elements, UDM can be replaced with data management network elements, SMF can be replaced with session management network elements, and UPF can be replaced with user plane network elements.

For convenience of description, in the embodiments of the present application, the device is an AMF entity and a UDM entity as examples to describe the method for establishing a session. For the implementation method of the device being a chip in the AMF entity and a chip in the UDM entity, refer to The specific descriptions of the devices being the AMF entity and the UDM entity will not be repeated.

In the network architecture shown in Figure 1, the terminal equipment is connected to the AMF through the N1 interface, the RAN is connected to the AMF through the N2 interface, and the RAN is connected to the UPF through the N3 interface. The UPFs are connected through the N9 interface, and the UPFs are interconnected through the N6 interface DN. SMF controls UPF through the N4 interface. AMF interfaces with SMF through N11 interface. AMF obtains terminal equipment subscription data from the UDM unit through the N8 interface, and SMF obtains terminal equipment subscription data from the UDM unit through the N10 interface.

It should be understood that the foregoing network architecture applied to the embodiments of the present application is only an example, and the network architecture applicable to the embodiments of the present application is not limited to this. Any network architecture that can implement the functions of the foregoing network elements is applicable to the present application. Application examples.

For example, in some network architectures, network function network element entities such as AMF network elements, SMF network elements, PCF network elements, BSF network elements, and UDM network elements are all called network function (NF) network elements; or, In some other network architectures, a collection of network elements such as AMF network elements, SMF network elements, PCF network elements, BSF network elements, UDM network elements, etc. can all be called control plane function network elements.

The technical solutions of the embodiments of this application can be applied to various communication systems, such as: global system for mobile communications (GSM) system, code division multiple access (CDMA) system, broadband code division multiple access (wideband code division multiple access, WCDMA) system, general packet radio service (GPRS), long term evolution (LTE) system, LTE frequency division duplex (FDD) system, LTE Time division duplex (TDD), universal mobile telecommunication system (UMTS), worldwide interoperability for microwave access (WiMAX) communication system, the future fifth generation (5th generation, 5G) system or new radio (NR), etc.

The terminal equipment in the embodiments of this application may refer to user equipment, access terminals, user units, user stations, mobile stations, mobile stations, remote stations, remote terminals, mobile equipment, user terminals, terminals, wireless communication equipment, user agents, or User device. The terminal device can also be a cellular phone, a cordless phone, a session initiation protocol (session initiation protocol, SIP) phone, a wireless local loop (WLL) station, a personal digital assistant (personal digital assistant, PDA), with wireless communication Functional handheld devices, computing devices or other processing devices connected to wireless modems, in-vehicle devices, wearable devices, terminal devices in the future 5G network, or future evolution of the public land mobile network (PLMN) Terminal equipment, etc., this embodiment of the application does not limit this.

The network device in the embodiment of the application may be a device used to communicate with a terminal device. The network device may be a global system for mobile communications (GSM) system or code division multiple access (CDMA) The base transceiver station (BTS) in the LTE system can also be the base station (NodeB, NB) in the wideband code division multiple access (WCDMA) system, or the evolved base station (evolved) in the LTE system. NodeB, eNB or eNodeB), it can also be a wireless controller in a cloud radio access network (CRAN) scenario, or the network device can be a relay station, access point, vehicle-mounted device, wearable device, and future The network equipment in the 5G network or the network equipment in the future evolved PLMN network, etc., are not limited in the embodiment of the present application.

In the embodiments of the present application, the terminal device or the network device includes a hardware layer, an operating system layer running on the hardware layer, and an application layer running on the operating system layer. The hardware layer includes hardware such as a central processing unit (CPU), a memory management unit (MMU), and memory (also referred to as main memory). The operating system may be any one or more computer operating systems that implement business processing through processes, for example, Linux operating system, Unix operating system, Android operating system, iOS operating system, or windows operating system. The application layer includes applications such as browsers, address books, word processing software, and instant messaging software. In addition, the embodiments of the application do not specifically limit the specific structure of the execution body of the method provided in the embodiments of the application, as long as the program that records the codes of the methods provided in the embodiments of the application can be provided according to the embodiments of the application. For example, the execution subject of the method provided in the embodiments of the present application may be a terminal device or a network device, or a functional module in the terminal device or network device that can call and execute the program.

In addition, various aspects or features of the present application can be implemented as methods, devices, or products using standard programming and/or engineering techniques. The term "article of manufacture" used in this application encompasses a computer program that can be accessed from any computer-readable device, carrier, or medium. For example, computer-readable media may include, but are not limited to: magnetic storage devices (for example, hard disks, floppy disks, or tapes, etc.), optical disks (for example, compact discs (CD), digital versatile discs (DVD)) Etc.), smart cards and flash memory devices (for example, erasable programmable read-only memory (EPROM), cards, sticks or key drives, etc.). In addition, various storage media described herein may represent one or more devices and/or other machine-readable media for storing information. The term "machine-readable medium" may include, but is not limited to, wireless channels and various other media capable of storing, containing, and/or carrying instructions and/or data.

With the development of 5G communication technology, the number of PDU sessions corresponding to upper-layer applications will inevitably increase. The ability of terminal devices to establish more PDU sessions is a business-driven need. Operators can customize different PLMN terminal device support according to the contract information of terminal devices The maximum number of PDU sessions. For a terminal device, the maximum number of PDU session IDs defined by the 5G communication protocol, the maximum number of PDU sessions actually supported by the terminal device, and the maximum number of PDU sessions supported by the terminal device under PLMN determine the maximum PDU that can be established When quantity, you need to know the three quantity values clearly.

Specifically, the maximum number of PDU session IDs defined by the 5G communication protocol has been described in the version number 24.501 6.4.1.5, which will not be repeated in this application; the maximum number of PDU sessions supported by terminal equipment under PLMN is based on the operator’s The subscription information of the terminal device is customized, which is equivalent to the value preset by the operator based on different PLMNs and different terminal devices; the maximum number of PDU sessions supported by the terminal device is a value known by the terminal device itself, which can be the manufacturing of the terminal device Specified by the manufacturer.

Specifically, in the process of communication between the terminal device and the network device, the network device does not notify the terminal device of the value of the maximum PDU session number supported by the terminal device under the aforementioned PLMN. But when the terminal device establishes a PDU session, when the network device receives a request message sent by the terminal device requesting the establishment of a PDU session, if it is determined that the maximum number of PDU sessions supported by the terminal device under the PLMN has reached, the network device will The terminal device sends indication information to notify the terminal device that the number of PDU sessions currently established has reached the maximum number of PDU sessions supported by the terminal device under the PLMN. Among them, the indication information is the rejection reason code #65 in the downlink non-access stratum transport (DL NAS TRANSPORT) message stipulated in the protocol, where the rejection reason code #65 indicates that the maximum number of PDU sessions has reached . Hereinafter, it can be referred to as reason code #65.

It should be understood that the description of the above solution is related to the existing 5G protocol. For example, 24.501 6.4.1.5 The maximum number of PDU sessions which a UE can establish in a PLMN is limited by whichever is the lowest of: the maximum number of PDU session IDs allowed by the protocol(as 11specified TS 24.007 [as 11specified] subclause 11.2.3.1b),the PLMN's maximum number of PDU sessions and the UE's implementation-specific maximum number of PDU sessions.24.5015.4.5.2.4Upon reception of a UL NAS TRANSPORT message to type, if the Payload IE N1 SM information", the Request type IE is set to "initial request"or"existing PDU session", and the AMF determines that the PLMN's maximum number of PDU sessions has already been already back to the F UE, the hall reached for the F UE UE the 5GSM message which was not forwarded and 5GMM cause#65"maximum number of PDU sessions reached" as specified in subclause 5.4.5.3.1 case h).24.501 6.4.1.5 NOTE1: In established several situations, when multiple sessions, when PDU ,the number of active PDU sessions that the UE has when 5GMM cause#65 is received Is not equal to the maximum number of PDU sessions reached in the network.

Further, after receiving the instruction information of the network device, the terminal device will not trigger the establishment of the PDU session by default. If the terminal device needs to re-establish a high-priority or emergency service PDU session, the terminal device needs to choose to release the established PDU session by itself, thereby establishing a new PDU session. The terminal tries to establish the PDU session again, and it does not guarantee the success of the PDU session establishment, which will consume the signaling interaction between the terminal device and the network device. Among them, the terminal device choosing to release an established PDU session generally does not choose a high-priority or emergency service PDU session for release.

However, since multiple PDU sessions can be established at the same time in a 5G system, when a terminal device initiates multiple PDU session establishment requests at the same time, it may happen that the network device sends the above indication information to the terminal device, but the maximum PDU session supported by the terminal device The number value is not reached, which leads to inaccuracy in the terminal device determining the number of PDU sessions established under the PLMN.

For example, if the PDU session ID defined by the 5G communication protocol is 0-15, the terminal device #1 knows that the maximum number of PDU session IDs defined by the 5G communication protocol is 16, or it is understood that 16 PDU session IDs are defined; further The terminal device #1 knows that the maximum number of PDU sessions actually supported by the terminal device #1 is 6; the operator determines that the maximum number of PDU sessions supported by the terminal device #1 under the PLMN is 5. When terminal device #1 is communicating with the network device, it cannot be determined that the maximum number of PDU sessions supported by terminal device #1 under the PLMN is 5. In the process of establishing a PDU session for the terminal device #1, according to the above-mentioned maximum number of PDU session IDs of 16 and the actual maximum number of PDU sessions supported by 6, it is preliminarily determined that the number of PDU sessions that can be established by the terminal device #1 is 6.

Assume that the terminal device #1 simultaneously initiates the 5th and 6th PDU session establishment requests after establishing the 4 PDU sessions. When the network device receives the multi-path PDU session establishment request, it is determined that if the multi-path PDU session is allowed to be established, the maximum number of PDU sessions supported by the terminal device #1 under the PLMN will be exceeded. Furthermore, the network device sends the aforementioned indication information to the terminal device #1, indicating that the maximum number of PDU sessions supported by the terminal device #1 under the PLMN has been reached.

After the terminal device #1 receives the indication information, it cannot be determined that the maximum number of PDU sessions supported by the terminal device #1 under the PLMN is 5. Instead, it is considered that the establishment of the fifth and sixth PDU sessions after the establishment of a 4-way PDU session is not successful, and it is concluded that the maximum number of PDU sessions that can be established by terminal device #1 is 4, which leads to the final determination of the maximum PDU session that can be established The quantity is wrong. Furthermore, the terminal device #1 was able to successfully establish the fifth PDU session. Due to a judgment error, when the terminal device #1 needs to establish the fifth PDU session, the fifth PDU session may not be established, or the fifth PDU session may be released. One PDU session of the non-emergency service in the established 4-way PDU session, and then the fifth PDU session is established.

In order to facilitate the understanding of the method for session establishment provided in the embodiments of this application, first briefly introduce several basic concepts involved in the embodiments of this application:

1. PLMN.

The PLMN involved in this application is a network established and operated by the government or an operator approved by the government to provide the public with land mobile communication services. For example, China Mobile, China Unicom, etc.

In other words, the operator maintains the network with the PLMN as the granularity for network maintenance. For different PLMNs and for different terminal equipment subscription data, the maximum number of packet data unit PDU sessions that the terminal equipment under the PLMN supports to establish is customized.

Specifically, the home PLMN (home public land mobile network, HPLMN) and visited PLMN (visited public land mobile network, VPLMN) are mainly involved in this application. Among them, HPLMN is the country's PLMN, and VPLMN refers to the PLMN in the roaming scenario.

It should be understood that the above-mentioned maximum number of PDU sessions supported by the terminal device under the PLMN is just a commonly used term, and does not constitute a limitation on this application. For example, it can also be referred to as the maximum number of PDU sessions supported by the terminal equipment at the PLMN level, or the maximum number of PDU sessions supported by the PLMN’s terminal equipment.

2. Terminal device registration process.

A terminal device that wants to obtain the services provided by the network device must first register with the network device. The registration process of the terminal device involved in the embodiment of this application is similar to that specified in the existing agreement. include:

1) Initial registration;

2) Mobile update registration;

3) Periodic registration.

Among them, the initial registration refers to the terminal device registering with the network device for the first time; the mobile update registration refers to the terminal device once it moves to a new time advanced (TA) cell, the new TA cell no longer belongs to the terminal If the registration area of the device is established, the terminal device will trigger mobile update registration; periodic registration refers to the periodical registration timer in the terminal device that expires and triggers periodic registration. This kind of registration is similar to the heartbeat mechanism, which is to let the network device know The terminal device is also turned on in the service area.

In the following, the registration process of the terminal device will be briefly introduced in conjunction with Figure 2. Fig. 2 is a flowchart of registration of a terminal device according to an embodiment of the present application.

S110: The terminal device sends a registration request message to the access network.

Wherein, the registration request message may be the registration request message in the aforementioned initial registration, mobile update registration or periodic registration process. It should be understood that the parameters carried in the registration request message in different registration types and scenarios are different. This application is not limited to this, and it may be a parameter that needs to be carried as stipulated in the existing agreement, which will not be repeated here.

S120: The access network selects an appropriate access management network element (destination access management network element) according to the parameters carried in the registration request message sent by the terminal device. Specifically, the process for the access network to select the access management network element is the selection method specified in the existing protocol, which is not limited in this application.

S130: The access network forwards the registration request message to the destination access management network element.

Specifically, the access network forwards the registration request message of the NAS layer to the access management network element through the N2 interface.

S140: The destination access management network element sends a request message for acquiring context information of the terminal device to the source access management network element.

The destination access management network element is an access management network element selected by the access network based on the parameters carried in the registration request message sent by the terminal device. The source access management network element is an access management network element selected based on the parameters carried in the registration request message sent by the terminal device once on the access network.

It should be understood that the foregoing destination access management network element and source access management network element are only examples, and the source access management network element may not be included when the terminal device registers for the first time.

S150: The source access management network element sends a response message to the destination access management network element, which carries the context information of the terminal device.

S160: The destination access management network element sends a request message for acquiring ID information of the terminal device to the terminal device.

S170: The terminal device sends a response message to the target access management network element, which carries ID information of the terminal device.

S180, the destination access management network element selects the authentication server function AUSF network element.

S190, an authentication process between the terminal device and the core network.

Specifically, the authentication process between the terminal device and the core network is the selection method specified in the existing agreement, which is not limited in this application.

S1100: The destination access management network element notifies the source access management network element of the registration result of the terminal device.

S1120: The destination access management network element selects a data management network element.

S1130: The destination access management network element registers the terminal device with the data management network element.

S1140: The destination access management network element obtains terminal device access and mobile subscription data, SMF selection subscription data, and context information of the terminal device in the SMF from the data management network element.

S1150: The data management network element notifies the source to access the management network element to register the terminal device.

S1160: The destination access management network element sends a registration reception message to the terminal device.

It should be understood that FIG. 2 is only a simple example, and does not all show the registration process of the terminal device, and mainly involves the steps and network elements that may be involved in the embodiments of the present application. The complete registration process of the terminal device can be obtained based on the existing protocol, and will not be repeated in this application.

3. PDU session.

The communication system supports the PDU connection service. The PDU connection service is the service of exchanging PDU data packets between the terminal device and the DN; the PDU connection service is implemented by the terminal device initiating the establishment of a PDU session. After a PDU session is established, a data transmission channel between the terminal device and the DN is established.

In order to solve the above-mentioned problem that the terminal device cannot accurately know the maximum number of PDU sessions that it can establish, this application provides a method for session establishment, in which the terminal device is notified through the AMF that the terminal device supports the establishment of the PLMN to which the core network belongs The maximum number of packet data unit PDU sessions enables the terminal device to accurately learn the maximum number of PDU sessions that can be established by itself, and improves the performance of the terminal device for establishing PDU sessions.

The following describes in detail the method for session establishment provided by the embodiments of the present application with reference to FIGS. 3-10.

The following describes the method for session establishment provided by the embodiment of the application from the flow of signaling interaction. FIG. 3 is a schematic flowchart of the method for session establishment provided by the embodiment of the application. Including terminal equipment and access management network elements, and steps S210-S220, these steps are described in detail below.

S210: The terminal device sends a registration request message to the access management function network element.

The registration request message is used to request the terminal device to be registered in the network belonging to the preset public land mobile communication network PLMN. Among them, the registration request message can be the initial registration request message sent when the terminal device registers with the network device for the first time, or the registration request message can be the terminal device moving to the new maximum timing advance TA cell, which has already If it does not belong to the registration area of the terminal device, the mobile update registration request message triggered by the terminal device, or the registration request message may be a periodic registration request message triggered by a periodic registration timer in the terminal device that expires. Specifically, the registration request message sent by the terminal device to the access management function network element in this application is a registration request message sent by the terminal device to the access management function network element via the access network. Specifically, the registration process of the terminal device is shown in Fig. 2 and will not be repeated here.

Exemplarily, when the method for establishing a session provided by the embodiment of this application is applied to a 5G communication system, the above-mentioned access management function network element may be the aforementioned AMF network element, or when the embodiment of this application provides When the method for establishing a session is applied to an LTE communication system, the aforementioned access management function network element may be the aforementioned MME network element.

S220: The terminal device receives the first message sent by the access management function network element.

Wherein, the first message carries a first parameter, and the first parameter indicates the maximum number of packet data unit PDU sessions that the terminal device supports to establish under a preset public land mobile communication network PLMN.

Exemplarily, the first parameter is a value of the maximum number of PDU sessions that the terminal device supports to establish under a preset PLMN. Or, there is a one-to-one correspondence between the first parameter and the maximum number of PDU sessions supported by the terminal device under the preset PLMN, and the one-to-one correspondence is stored in the terminal device and the access management function network element, namely The terminal device and the access management function network element can determine the maximum number of PDU sessions supported by the terminal device under the preset PLMN based on the first parameter and the one-to-one correspondence.

For example, the preset maximum number of PDU sessions supported by the terminal device under the PLMN is 5. The first parameter is 5, or the first parameter is X, and the one-to-one correspondence between the first parameter and the maximum number of PDU sessions supported by the terminal device under the preset PLMN indicates that when the first parameter is X At this time, the preset maximum value of the number of PDU sessions supported by the terminal device under the PLMN is 5.

For example, the one-to-one correspondence may be: the maximum number of PDU sessions supported by the terminal device under the preset PLMN=first parameter-1.

It should be understood that the above-mentioned first parameter being 5 or X is just an example. Other terminal devices can clearly obtain the first parameter of the maximum number of PDU sessions supported by the terminal device under the preset PLMN based on the first parameter. All the first parameters are within the protection scope of this application, and the first parameters will not be listed here. A possible form of a parameter.

Exemplarily, the first message is a registration reception message.

Exemplarily, the first message is a PDU session establishment rejection message. For example, the PDU session establishment rejection message may be the aforementioned indication information (reason code #65), or the PDU session establishment rejection message may also be existing signaling other than the reason code #65. Then, the flow of the method for session establishment shown in FIG. 3 further includes: the terminal device sends a PDU session establishment request message to the access management function network element. Wherein, the terminal device described in this application sending the PDU session establishment request message to the access management function network element may be a PDU session establishment request sent by the existing terminal device to the access management function network element when it needs to establish a PDU session news. This application does not limit the PDU session establishment request message.

Exemplarily, the first message is a message sent to the terminal device after the access management function network element determines the first parameter. That is, the first message is the interaction signaling between the newly added access management function network element and the terminal device, and is used to notify the terminal device of the above-mentioned first parameter.

It should be understood that the above-mentioned first message may be newly-added interactive signaling between the access management function network element and the terminal device, or the first message may also be the reuse of existing signaling. The first message may be the existing interactive signaling between the access management function network element and the terminal device. The embodiment of the present application only adds an information element (information element, IE) to the existing interactive signaling. IE is the first parameter mentioned above. The embodiment of the present application does not limit the specific form of the first message, as long as the first message carrying the above-mentioned first parameter is within the protection scope of the present application. In addition, the first message involved in the embodiments of the present application is not limited to only the registration reception message or the PDU session establishment rejection message when the existing signaling is reused, and it can also be other existing signaling. , This is no longer an example one by one.

Specifically, the process of the method for session establishment provided by the embodiment of the application before S220 further includes S221, the access management function network element determines the foregoing first parameter, and S222, the access management function network element saves the foregoing first parameter.

The access management function network element may determine the foregoing first parameter in the following two ways:

method one:

The maximum number of PDU sessions supported by the terminal device under the aforementioned preset PLMN is customized for the terminal device by the operator according to the subscription data of the terminal device. In addition, the maximum number of PDU sessions supported by the terminal device under the PLMN and the subscription data of the terminal device are stored in the data management network element together. So in terms of mode, the method flow shown in FIG. 3 also includes S212 and S213. The access management function network element sends a query message to the data management network element, and the query message is used to query the data management network element for the maximum number of PDU sessions supported by the terminal device under the preset PLMN; the data management network element Send a feedback message to the access management function network element, that is, after receiving the query message, the data management network element carries the first parameter used to indicate the maximum number of PDU sessions established by the terminal device under the preset PLMN in the feedback message Informing the access management function network element. Then, in the first mode, the access management function network element needs to obtain the above-mentioned first parameter from the data management network element, save the first parameter in the local memory, and then carry the first parameter in the first message to notify Terminal Equipment.

Exemplarily, when the method for establishing a session provided by the embodiment of the present application is applied to a 5G communication system, the aforementioned data management network element may be the aforementioned UDM network element, or when the method provided by the embodiment of the present application is used When the session establishment method is applied to an LTE communication system, the above-mentioned data management network element may be the aforementioned HSS network element.

Optionally, the query message may be an access authentication message. For example, when the access management function network element is in the process of authenticating with the data management network element, the data management network element carries the above-mentioned first parameter in the signaling that transmits the subscription data of the terminal device and informs the access management function network. yuan. Furthermore, the access management function network element receives the signaling sent by the data management network element, obtains the first parameter, and records the first parameter in the access management function network element. And notify the terminal device through the above-mentioned first message.

Way two:

The foregoing first parameter is determined by the access management function network element according to the local policy in the access management function network element. Among them, the local policy in the network element of the access management function is preset by the operator, which is not limited in this application.

For example, in a roaming scenario, a visited, V-AMF (visited, V-AMF) network element can determine the maximum number of PDU sessions supported by the terminal device under the PLMN under the VPLMN according to a local policy.

It should be understood that after receiving the first message, the terminal device can determine the maximum number of PDU sessions that the terminal device can establish according to the first parameter in the first message, that is, the terminal device determines the maximum number of PDU sessions that the terminal device is allowed to establish based on the first parameter. The number of PDU sessions.

Specifically, it can be known from the foregoing that the maximum number of PDU sessions that a terminal device can establish is based on the maximum number of PDU session IDs defined by the 5G communication protocol, the maximum number of PDU sessions supported by the terminal device under PLMN, and the terminal device The minimum value among the maximum number of PDU sessions actually supported is determined. Among them, the maximum number of PDU session IDs defined by the 5G communication protocol is clear, and the maximum number of PDU sessions actually supported by the terminal device is also clear. After the terminal device receives the first message and obtains the first parameter, the value of the maximum number of PDU sessions supported by the terminal device under the PLMN is also clear. Furthermore, the terminal device determines the minimum of the three values based on the three known values as the maximum number of PDU sessions that the terminal device can establish.

For example, the maximum number of PDU session IDs defined by the 5G communication protocol is 16, the maximum number of PDU sessions actually supported by the terminal device is 6, and the first parameter is 5. According to 16, 6 and 5, the terminal device determines that the maximum number of PDU sessions that the terminal device can establish is min{16, 6, 5}=5.

further. When the terminal device needs to establish the first PDU session, it can determine whether to establish the first PDU session according to the maximum number of PDU sessions that the terminal device can establish.

Situation 1:

When the first message is a registration to receive message. That is, the terminal device has learned the maximum number of PDU sessions that can be established before initiating the session establishment procedure.

Exemplarily, when the number of PDU sessions that the terminal device has established is less than the maximum number of PDU sessions allowed by the terminal device, the terminal device establishes the first PDU session.

For example, the maximum number of PDU sessions that a terminal device can establish is 5. When the first PDU session needs to be established, the number of PDU sessions that the terminal device has established is 4. Then the terminal device continues to initiate the PDU session establishment process to establish the aforementioned first PDU session.

Exemplarily, when the number of PDU sessions that the terminal device has established is equal to the maximum number of PDU sessions that the terminal device is allowed to establish, the terminal device refuses to establish the first PDU session.

For example, the maximum number of PDU sessions that a terminal device can establish is 5. When the first PDU session needs to be established, the number of PDU sessions that the terminal device has established is 5. Then the terminal device refuses to initiate the PDU session establishment process and refuses to establish the aforementioned first PDU session.

Exemplarily, when the number of PDU sessions that the terminal device has established is equal to the maximum number of PDU sessions allowed by the terminal device, the terminal device establishes the first PDU session after releasing the second PDU session, wherein the second PDU The session is any one of the PDU sessions established by the terminal device.

For example, the maximum number of PDU sessions that a terminal device can establish is 5. When the first PDU session needs to be established, the number of PDU sessions that the terminal device has established is 5. Then the terminal device releases the second PDU session among the established PDU sessions, and establishes the aforementioned first PDU session. In order to ensure the smooth progress of the emergency service, the second PDU session should be a PDU session other than the emergency service PDU session in addition to the established PDU sessions.

Situation 2:

When the first message is a PDU session establishment rejection message. That is, the terminal device does not clearly determine the maximum number of PDU sessions that the terminal device can establish before initiating the session establishment process.

In the following, after activating a multi-channel session, the terminal device simultaneously initiates the establishment of two PDU sessions (PDU session #1 and PDU session #2) as an example to illustrate how the terminal device determines whether to establish a two-channel PDU session.

After the access management function network element receives the two-way PDU session establishment request message, it is determined according to the first parameter cached locally that the number of PDU sessions requested to be established by the terminal device has reached the first parameter. Then, the access management function network element sends a PDU session establishment rejection message to the terminal device, and carries the first parameter in the PDU session establishment rejection message. The terminal device clarifies the maximum number of PDU sessions that it can establish based on the first parameter.

For example, first, the maximum number of PDU session IDs defined by the terminal device based on the 5G communication protocol is 16, and the maximum number of PDU sessions actually supported by the terminal device is 6, and the maximum number of PDU sessions that can be established by the terminal device is 6. Then, the terminal device only needs to have the number of established PDU sessions less than or equal to 4 before initiating the PDU session #1 and PDU session #2 establishment request.

Secondly, suppose that the terminal device successfully establishes a 4-way PDU session connection and initiates a request for establishing PDU session #1 and PDU session #2 at the same time.

Furthermore, after the access management function network element receives the PDU session #1 and PDU session #2 establishment request message, according to the size of the locally cached first parameter (for example, the first parameter is 5), it determines that it exceeds the size of the terminal device connected to The value of the maximum number of PDU sessions supported by the terminal device under the PLMN to which the PLMN belongs. Then, the access management function network element sends a PDU session establishment rejection message to the terminal device, and the PDU session establishment rejection message carries the first parameter.

According to the received first parameter of 5, and the maximum number of PDU session IDs defined by the 5G communication protocol, the terminal device determines that the maximum number of PDU sessions that the terminal device actually supports is 6 5.

Finally, the terminal device here judges whether to initiate a PDU session establishment request based on the maximum number of PDU sessions that can be established by itself is 5. Specifically, determining whether to initiate a PDU session establishment request is similar to the above-mentioned situation 1, and will not be repeated here.

Exemplarily, when the foregoing first parameter changes, the access management function network element sends an update message to the terminal device, and the update message includes the second parameter. Among them, the second parameter is the first parameter after the change.

For example, because the package of the terminal device has changed, that is, the maximum number of PDU sessions that can be established under the preset PLMN described above has changed, the access management function network element, after learning that the first parameter has changed, will change the first parameter after the change. The second parameter is carried in the update message to notify the terminal device.

Optionally, the update message is a registration reception message in a mobile or periodic registration update process.

For example, as shown in FIG. 4, FIG. 4 is a schematic flowchart of a method for updating a first parameter according to an embodiment of the present application. include:

S310: The terminal device sends a registration request message to the access management network element.

The registration request message is a registration request message in the mobile update registration or periodic registration process.

S320: The access management network element determines the second parameter.

The access management network element determines that the aforementioned first parameter value has changed, and calls the changed first parameter the second parameter.

Specifically, the access management network element learning that the first parameter has changed may be: the data management network element determines that the above-mentioned first parameter has changed according to the subscription data of the terminal device, and notifies the access management network of the result of the change of the second parameter Or, the local policy of the access management network element has changed, so that the access management network element determines that the first parameter has changed.

S330: The access management network element sends a registration reception message to the terminal device.

The registration reception message includes the aforementioned second parameter (maximum number of PDU sessions for the UE), and the second parameter indicates the maximum number of PDU sessions that the changed terminal device supports to establish under the preset PLMN.

S340, the registration is completed.

Optionally, the update message is a configuration update command in the terminal configuration update procedure.

For example, as shown in FIG. 5, FIG. 5 is a schematic flowchart of another method for updating a first parameter according to an embodiment of the present application. include:

S410: The access management network element determines the second parameter.

S420: The access management network element sends a configuration update command to the terminal device.

The configuration update command (configuration update) includes the above-mentioned second parameter, and the second parameter indicates the maximum number of PDU sessions that the changed terminal device supports to establish under the preset PLMN.

S430, the configuration update is completed.

Optionally, the update message is newly-added signaling between the terminal device and the access management function network element, and is used to notify that the aforementioned first parameter has changed.

It should be understood that the specific form of the update message in this application is not limited, and it may be any kind of signaling that can be used to carry the above-mentioned second parameter.

Further, the method for establishing a session provided in the embodiment of the present application can also be applied to establish a session after the terminal device switches from one communication system to another communication system.

Exemplarily, the method flow shown in FIG. 3 further includes S211, the terminal device switches from the first communication system to the second communication system.

It should be understood that the "first" and "second" in this application are only used for distinguishing description, and should not constitute any limitation to this application. Among them, the first communication system and the second communication system only distinguish different communication systems.

Optionally, the first communication system may be an LTE system, and the second communication system may be a 5G system;

Optionally, the first communication system may be a 5G system, and the second communication system may be an LTE system;

Optionally, the first communication system may be an LTE system, and the second communication system may be a WCDMA system.

It should be understood that the embodiments of the present application do not limit which two communication systems the first communication system and the second communication system are. It is only restricted that the first communication system and the second communication system are two different communication systems.

Exemplarily, before the terminal device switches from the first communication system to the second communication system, the number of PDU sessions established by the terminal device in the first communication system is M, and M is a positive integer. Furthermore, when the terminal device switches from the first communication system to the second communication system, it is necessary to transfer the M-way PDU session from the first communication system to the second communication system.

Specifically, the switching of the terminal device from the first communication system to the second communication system includes the following two situations:

Case 1: The first communication system and the second communication system have different system switching interfaces.

Wherein, the inter-system switching interface between the first communication system and the second communication system is used to directly transfer the bearer in the first communication system to the second communication system, that is, the terminal device is switched from the first communication system to the second communication system. In the communication system, there is no need to re-establish the PDU session established in the first communication system in the second communication system.

Specifically, in the following situation, when the terminal device switches from the first communication system to the second communication system, a registration process needs to be initiated in the second communication system. The registration process includes:

First, the registration request message sent by the terminal device to the access management function network element carries first status indication information, and the first status indication information is used to indicate the status of the M-channel PDU session after it is transferred to the second communication system;

Secondly, after the access management function network element receives the registration request message, it determines the active N PDU sessions among the M PDU sessions based on the maximum number of PDU sessions supported by the terminal device under the PLMN, where M is a positive integer, and N is A positive integer less than or equal to M;

Then, the access management function network element sends a registration reception message to the terminal device. The registration reception message carries second status indication information and a first parameter indicating the maximum number of PDU sessions established by the terminal device under the PLMN. Wherein, the second status indication information is used to indicate the N PDU sessions in the active state among the M PDU sessions;

Finally, the terminal device determines that the N-way PDU session is in the active state according to the second state indication information.

For example, a terminal device establishes a 10-way PDU session in the first communication system, and after the terminal device switches from the first communication system to the second communication system, it transfers the 10-way PDU session to the second communication system and then The registration process is initiated in the communication system. Among them, the registration request message carries the status information of the 10-way PDU session as the active state, and after the access management function network element receives the registration request message, it determines the number of PDU sessions supported by the terminal device under the PLMN in its own buffer. There are only 5 PDU sessions in the active state among the 10 PDU sessions. The access management function network element informs the terminal device which 5-way PDU session is active. After the terminal device receives the registration reception message, it will notify the 10-way PDU session in addition to the 5-way PDU session notified by the access management function network element. The 5-way PDU session is determined to be inactive.

In summary, in the situation, although the PDU session established in the first communication system can be directly transferred to the second communication system through the different system switching interface between the first communication system and the second communication system, if it is in the active state The number of PDU sessions exceeds the network device’s limit on the maximum number of PDU sessions that the terminal device supports under PLMN. The network device will select some PDU sessions for deactivation. The terminal device will respond accordingly after receiving the notification from the network device. Perform deactivation. Among them, deactivation refers to changing the PDU session in the active state to the inactive state.

Case 2: There is no different system switching interface between the first communication system and the second communication system.

Specifically, in case 2, when the terminal device switches from the first communication system to the second communication system, it still needs to initiate a registration process in the second communication system. The registration process includes:

First, a registration request message sent by the terminal device to the access management function network element;

Secondly, the access management function network element sends a registration reception message to the terminal device. The registration reception message carries a first parameter indicating the maximum number of PDU sessions established by the terminal device under the PLMN.

Finally, the terminal device determines the maximum number of PDU sessions that the terminal device is allowed to establish according to the registration received message. Based on the determined maximum number of PDU sessions allowed to be established by the terminal device, determine the N PDU sessions that can be established in the M PDU sessions.

For example, the terminal device establishes a 10-way PDU session in the first communication system, and after the terminal device switches from the first communication system to the second communication system, it initiates the registration process in the second communication system. It is learned that the maximum number of PDU sessions allowed to be established by the terminal device is 5, the maximum number of PDU session IDs defined based on the 5G communication protocol is 16, and the maximum number of PDU sessions actually supported by the terminal device is 6 to determine the maximum number of PDU sessions allowed by the terminal device Is 5. Furthermore, the terminal device selects 5 PDU sessions among the 10 PDU sessions to initiate a PDU session establishment process.

In summary, in case 2, the PDU session established in the first communication system by the terminal device needs to select the PDU established in the first communication system in the second communication system after switching from the first communication system to the second communication system All or this part of the PDU session in the session re-initiates the PDU session establishment process.

The method for session establishment provided by the embodiments of the present application is described in detail above with reference to FIGS. 3 to 5. The following describes in detail how the method for session establishment of this application is applied in different situations with reference to FIGS. 6-10.

Fig. 6 is a schematic diagram of a session establishment provided by an embodiment of the present application. Applied in a 5G system, it means that the terminal device obtains the above-mentioned first parameter during the registration phase, and determines the maximum number of PDU sessions that it can establish. include:

S510: The UE sends a registration request message to the AMF.

The registration request message (registration request) may be a registration request message in the initial registration, mobile update registration, or periodic registration process. This application does not limit this.

S520, AMF and UDM perform authentication interaction.

In the process of AMF and UDM signaling interaction, the AMF obtains the maximum number of PDU sessions supported by the UE in the PLMN. This information can be included in the UE subscription data and sent by the UDM to the AMF. It should be understood that if it is not included in the subscription data, it can also be obtained from the AMF local policy, and then the AMF informs the terminal through the newly added IE.

The AMF itself buffers the maximum number of PDU sessions supported by the UE under the PLMN.

It should be understood that S510 and S520 are the registration procedures of the terminal device, which have been explained in FIG. 2 and will not be detailed here.

S530: The AMF sends a registration reception message to the UE.

The registration acceptance message (registration accept) adds an IE (PLMN’s maximum allowed number of PDU session), which is used to indicate the maximum number of PDU sessions supported by the UE under the PLMN.

For example, as shown in FIG. 7, FIG. 7 is a schematic diagram of a registration reception message provided by an embodiment of the present application. include:

Original information and the newly added IE, where the original information refers to the information included in the existing registration reception message, for example, the original information includes registration area, network slice subscription change signs, allowing NSSAI and other prior art registration reception messages Some original information is not limited in this application; the newly added IE is for AMF to add 4 bytes of special information to the registration reception message after determining the maximum number of PDU sessions supported by the UE under the PLMN.

Specifically, the number of bytes occupied by the newly added IE may be a number of bytes other than the aforementioned 4 bytes, which is not limited in this application. It should also be understood that FIG. 7 is only a schematic diagram. The newly added IE can be located at any position in the registration reception message. Specifically, the resources occupied by the newly added IE may be the resources reserved in the registration reception message, or It is to carry the newly added IE and allocate the resources to register to receive the message, which will not be illustrated one by one here.

S540: The UE determines the maximum number of PDU sessions allowed to be established.

After receiving the registration reception message, the UE determines the maximum number of PDU sessions supported by the UE in the PLMN based on the newly added IE in the registration reception message.

Further, the UE determines the maximum number of PDU sessions allowed to be established based on the maximum number of PDU session IDs defined by the 5G communication protocol, the maximum number of PDU sessions actually supported by the UE, and the maximum number of PDU sessions supported by the UE under the PLMN.

For example, the new IE in S530 occupies 4 bytes, indicating that the maximum number of PDU sessions supported by the UE under PLMN is 5, the maximum number of PDU session IDs defined by the 5G communication protocol is 16, and the maximum PDU session actually supported by the UE The number value is 6. The UE determines the maximum number of PDU sessions that the UE can establish according to 16, 6, and 5 as min{16, 6, 5}=5.

S550: The UE determines whether to establish a PDU session.

Each time the UE establishes a PDU session, it needs to determine whether it is within the range of the number of PDU sessions allowed to be established.

For example, when one or more PDU sessions need to be established, if the UE determines that the number of established PDU sessions does not exceed the allowed number of PDU sessions, the UE initiates the PDU session establishment process; if the UE determines that the number of established PDU sessions is equal to the allowed establishment The number of PDU sessions. The UE chooses to refuse to establish a PDU session or to establish a new PDU session that needs to be established through an appropriate established PDU session.

Assuming that there is a PDU session that needs to be established, this PD session is the first PDU session, and the number of established PDU sessions does not exceed the allowed number of PDU sessions, and the UE initiates a PDU session establishment process.

S560-S590, the process of establishing a PDU session for the UE, briefly described as follows:

UE sends PDU session establishment request message to AMF (PDU session establishment request)-AMF forwards PDU session establishment request message to SMF-UPF domain SMF interaction signaling, establishes PDU session-SMF sends PDU session establishment reception message to AMF (PDU session establishment) accept)-AMF forwards the PDU session establishment reception message to the UE.

Further, when there are more PDU sessions to be established, if the number of PDU sessions is still not exceeded, repeat the above S550-S590;

If the PDU session that needs to be established exceeds the allowed number of PDU sessions, and the UE determines to refuse to establish the PDU session, repeat the above-mentioned S550 and then execute S591 to refuse to establish the PDU session; and S560-S590 are no longer executed.

If the PDU session that needs to be established exceeds the allowed number of PDU sessions, and the UE determines to release the established PDU session, and when the PDU session is established, repeat the above S550 and then execute S592 to release the PDU session; then execute S560-S590 .

For example, when the UE determines that the number of PDU sessions that can be established is 5, and after the UE successfully establishes a 5-way PDU session, when there is a 6th PDU session to be established, since the UE knows that the number of PDU sessions that can be established is 5, initiate a PDU session again When creating a request, AMF will feed back #65 mentioned above. Therefore, in this embodiment, the UE does not need to blindly try to establish the 6th PDU session again without making any changes; instead, it refuses to establish the 6th PDU session, or releases one of the first 5 PDU sessions. Session, and then establish the sixth PDU session.

Fig. 6 illustrates the specific process in which the UE learns the first parameter and establishes a PDU session in the registration process. It can be seen from the description of FIG. 4 that the UE learning the first parameter may also be learned during the establishment of the PDU session. In the following, in conjunction with FIG. 8, it will be described in detail that the UE learns the above-mentioned first parameter and establishes the PDU session during the PDU session establishment process.

Fig. 8 is a schematic diagram of another session establishment provided by an embodiment of the present application. When applied to a 5G system, it means that the terminal device obtains the above-mentioned first parameter during the PDU session establishment phase, and determines the maximum number of PDU sessions that it can establish. include:

S610: The UE sends a registration request message to the AMF.

The registration request message may be a registration request message in the initial registration, mobile update registration, or periodic registration process. This application does not limit this.

S620, AMF and UDM perform authentication interaction.

It should be understood that S610 and S620 are the registration procedures of the terminal device, which have been explained in FIG. 2 and will not be detailed here.

S630: The AMF sends a registration reception message to the UE.

The difference from that shown in Figure 6 is that the newly added IE is not included in the registration reception message. To receive messages for existing registrations, this application is not limited to this.

S640: The UE establishes a PDU session.

After the UE is successfully registered, a PDU session is established in the communication system.

Specifically, the UE does not know the maximum number of PDU sessions supported by the UE under the PLMN at this time. The UE can only learn the maximum number of PDU session IDs defined by the 5G communication protocol and the maximum number of PDU sessions actually supported by the UE. Then the UE cannot accurately determine the maximum number of PDU sessions that it can establish when establishing a PDU session. It can only be estimated based on the maximum number of PDU session IDs defined by the 5G communication protocol and the maximum number of PDU sessions actually supported by the UE. The maximum number of PDU sessions.

For example, the maximum number of PDU session IDs defined by the 5G communication protocol is 16, and the maximum number of PDU sessions actually supported by the UE is 6. According to 16 and 6, the UE roughly estimates that the maximum number of PDU sessions that the UE can establish is min{16, 6}=6.

The process of UE establishment of PDU session is briefly described as follows:

UE sends PDU session establishment request message to AMF -AMF forwards PDU session establishment request message to SMF -UPF domain SMF exchange signaling, establishes PDU session -SMF sends PDU session establishment reception message to AMF -AMF forwards PDU session establishment reception message to UE .

S650: The UE simultaneously initiates a multiple PDU session establishment request message.

Assume that the maximum number of PDU sessions supported by the UE under the PLMN buffered by the AMF in S620 is 5. After the UE has established a 4-way PDU session, it simultaneously initiates the fifth and sixth PDU session establishment requests. Since the maximum number of PDU sessions supported by the UE under the PLMN learned by the AMF is 5, when the AMF receives the 5th and 6th PDU session establishment request messages, it is determined that the maximum number of PDU sessions supported by the UE under the PLMN has been reached , Will feed back the PDU session establishment rejection message (reason code #65).

S660: The AMF sends a PDU session establishment rejection message to the UE.

An IE is added to the PDU session establishment rejection message, and the IE is used to indicate the maximum number of PDU sessions supported by the UE in the PLMN.

Specifically, the PDU session establishment rejection message (reason code #65) is similar to the registration reception message shown in FIG. 7. The reason code #65 in this application is different from the existing reason code #65 in that IE is added. The original information in the newly added IE and the reason code #65 are carried in the reason code #65, and the specific position of the newly added IE in the reason code #65 is not limited. Among them, the original information refers to the information included in the existing reason code #65, which is not involved in this application, so it will not be repeated.

S670: The UE determines the maximum number of PDU sessions allowed to be established.

After receiving the PDU session establishment rejection message, the UE determines the maximum number of PDU sessions supported by the UE in the PLMN based on the newly added IE in the PDU session establishment rejection message.

For example, the newly added IE in S660 occupies 4 bytes, indicating that the maximum number of PDU sessions supported by the UE under PLMN is 5, the maximum number of PDU session IDs defined by the 5G communication protocol is 16, and the maximum PDU session actually supported by the UE The number value is 6. The UE determines the maximum number of PDU sessions that the UE can establish according to 16, 6, and 5 as min{16, 6, 5}=5.

S680: The UE determines whether to establish a PDU session again.

Before establishing a PDU session again, the UE needs to determine whether it is within the range of the number of allowed PDU sessions to be established.

If the PDU session that needs to be established exceeds the range of the number of PDU sessions allowed to be established, and the UE determines to refuse to establish the PDU session, the session establishment process shown in FIG. 8 ends.

If the PDU session to be established exceeds the range of the number of PDU sessions allowed to be established, and the UE determines to release the established PDU session, the UE releases the PDU session; then S640 is performed again.

For example, when the UE judges that the number of PDU sessions that can be established is 5, and after the UE successfully establishes a 4-way PDU session, when there are 5th and 6th PDU sessions to be established, since the UE knows that the number of PDU sessions that can be established is 5. The UE directly initiates the fifth PDU session establishment request, and for the sixth PDU session, the UE does not need to blindly try to establish the sixth PDU session again without making any changes; instead, it refuses to establish the sixth PDU session. Or, release one of the first five PDU sessions, and then establish a sixth PDU session.

It should be understood that the indication of initiating a multiple PDU session shown in S650 is an example. When a PDU session is initiated, the reason code #65 fed back by the AMF may still carry the aforementioned IE. Taking the initiation of a multi-channel PDU session as an example, it is to highlight that in the prior art, if the UE initiates a multi-channel PDU session establishment request, after receiving the reason code #65, the maximum number of PDU sessions that can be established may be wrong. In the method for session establishment provided by the embodiments of this application, when the UE initiates multiple PDU sessions at the same time, by adding an IE to the reason code #65, it indicates the maximum number of PDU sessions that the UE supports under the PLMN. The newly added IE accurately determines the maximum number of PDU sessions that the UE is allowed to establish.

Exemplarily, the method for establishing a session provided in the embodiment of the present application can also be applied in a load transfer scenario when a different system is switched.

The following briefly introduces how to establish a PDU session when there is a different system handover in conjunction with FIG. 9 and FIG. 10.

FIG. 9 is a schematic diagram of another session establishment provided by an embodiment of the present application. The terminal device is in the LTE system, and without the N26 interface, the network device in the LTE system triggers the terminal device to switch to the 5G system from another system.

S710: The UE implements handover between different systems.

S720. The UE sends a registration request message to the AMF.

The UE initiates the registration process in the 5G system.

S730, AMF and UDM perform authentication interaction.

S740: The AMF sends a registration reception message to the UE.

An IE is added to the registration reception message, and the IE is used to indicate the maximum number of PDU sessions supported by the UE in the PLMN. It is similar to the registration reception message shown in S530 in FIG. 6, and will not be repeated here.

S750: The UE determines the maximum number of PDU sessions allowed to be established.

S760: The UE transfers the PDU session.

The UE transfers the PDU session established in the LTE system to the 5G system.

Specifically, the UE selects which PDU sessions to transfer according to the maximum number of PDU sessions allowed to be established.

For example, when the number of PDU sessions established in LTE after the system switch does not exceed the maximum number of PDU sessions allowed by the UE, the UE directly executes S770 to establish PDU sessions; or,

When the number of PDU sessions established in LTE after the system switch exceeds the maximum number of PDU sessions allowed by the UE, the UE selects the PDU sessions that meet the maximum number of PDU sessions allowed by the UE, and executes S770 to establish a PDU session.

For example, the UE determines that the maximum number of PDU sessions allowed to be established is 5, and the number of PDU sessions established by the UE in the LTE system is 10. Then, the UE selects 5 PDU sessions among the 10 PDU sessions to transfer to the 5G system.

S770: The UE establishes a PDU session.

Specifically, the process of establishing a PDU session by the UE will not be repeated.

S780: The UE determines whether to establish a PDU session.

For example, when one or more PDU sessions need to be established, if the UE determines that the number of established PDU sessions does not exceed the allowed number of PDU sessions, the UE initiates the PDU session establishment process; if the UE determines that the number of established PDU sessions is equal to the allowed establishment The number of PDU sessions. The UE chooses to refuse to establish a PDU session, or to establish a new PDU session to be established by releasing the established PDU session.

Figure 9 shows the process of establishing a PDU session by the UE when there is a handover between different systems and there is no N26 interface. The following briefly explains how the UE establishes a PDU session after a different system handover when there is N26 with reference to FIG. 10.

FIG. 10 is a schematic diagram of yet another session establishment provided by an embodiment of the present application. The terminal device is in the LTE system, and when there is an N26 interface, the network device in the LTE system triggers the terminal device to switch to the 5G system from another system.

S810: The UE implements handover between different systems.

The UE transfers the bearer under the S1 interface in the LTE system to the N1 interface in the 5G system through the N26 interface to complete the PDU session recovery. Among them, PDU session recovery refers to the PDU session that the UE will establish in the LTE system and directly transfer to the 5G system through the N26 interface.

S820: The UE sends a registration request message to the AMF.

The UE initiates the registration process in the 5G system. Specifically, the UE carries the active PDU session status (PDU session status) in the registration request message and sends it to the AMF.

S830, AMF and UDM perform authentication interaction.

S840: The AMF determines whether the PDU session needs to be released.

AMF judges whether the number of activated PDU sessions carried by the UE in the registration request message exceeds the maximum number of PDU sessions supported by the UE under the PLMN. If it exceeds the maximum number of PDU sessions supported by the UE under the PLMN, AMF triggers the network side to release the PDU sessions locally to ensure the maximum number of PDU sessions supported by the UE under the PLMN Limit on the number of PDU sessions.

S850: The AMF sends a registration reception message to the UE.

An IE (PLMN’s maximum allowed number of PDU session) is added to the registration reception message. This IE is used to indicate the maximum number of PDU sessions supported by the UE under the PLMN and the PDU session status of the final active state (PDU session status).

For example, the newly added IE#1 is used to indicate the maximum number of PDU sessions supported by the UE under the PLMN; the newly added IE#2 is used to indicate the PDU session information in the active state.

S860: The UE determines the maximum number of PDU sessions allowed to be established.

S870, the UE performs deactivation.

The UE receives the IE indicating the PDU session information in the active state in the registration message according to the registration. Perform local deactivation to ensure that the number of PDU sessions in the 5G system meets the maximum number of PDU sessions that the UE is allowed to establish after the conversion of different systems.

S880: The UE determines whether to create a new PDU session in the 5G system.

Before establishing a PDU session again in the 5G system, the UE needs to determine whether it is within the range of the number of allowed PDU sessions to be established.

For example, when one or more PDU sessions need to be established, if the UE determines that the number of active PDU sessions does not exceed the number of allowed PDU sessions, the UE initiates the PDU session establishment process; if the UE determines that the number of active PDU sessions is equal to The number of PDU sessions allowed to be established, and the UE chooses to refuse to establish a PDU session, or to establish a new PDU session to be established by releasing the active PDU session.

The method for establishing a session and the application of the method for establishing a session provided by the embodiments of the present application are described in detail above with reference to FIGS. 3-10. The following describes in detail the terminal device provided by the embodiments of the present application with reference to FIGS. 11-14 , Access management function network element and data management network element.

Refer to FIG. 11, which is a schematic diagram of the terminal device 10 proposed in the present application. As shown in Figure 11, the device 10 includes a processor 110 and a memory 120

And one or more programs, wherein the one or more programs are stored in the memory 120, and when the one or more programs are executed by the processor 110, the terminal device is caused to perform the following steps:

Sending a registration request message to the access management function network element, where the registration request message is used to request registration to a network belonging to a preset public land mobile communication network PLMN;

Receive a first message sent by the access management function network element, where the first message carries a first parameter, and the first parameter indicates the maximum packet data unit that the terminal device supports to establish under the preset PLMN The number of PDU sessions. The terminal device 10 completely corresponds to the terminal device in the method embodiment, and the terminal device 10 is used to execute the corresponding steps performed by the terminal device in the method embodiment shown in FIGS. 3 to 10.

Wherein, when the one or more programs are executed by the processor 110, the terminal device 10 executes the steps received in the method embodiment. For example, step 220 of receiving the first message from the access management function network element in FIG. 3 is performed. Referring to FIG. 12, FIG. 12 is a schematic structural diagram of a terminal device 20 applicable to an embodiment of the present application. The terminal device 20 can be applied to the system shown in FIG. 1. For ease of description, FIG. 12 only shows the main components of the terminal device. As shown in FIG. 12, the terminal device 20 includes a processor, a memory, a control circuit, an antenna, and an input and output device. The processor is used to control the antenna and the input and output device to send and receive signals, the memory is used to store a computer program, and the processor is used to call and run the computer program from the memory to execute the corresponding process and/or executed by the terminal device in the communication method proposed in this application. Or operation. I won't repeat them here.

Those skilled in the art can understand that, for ease of description, FIG. 12 only shows a memory and a processor. In actual terminal devices, there may be multiple processors and memories. The memory may also be referred to as a storage medium or a storage device, etc., which is not limited in the embodiment of the present application.

FIG. 13 is a schematic block diagram of an access management function network element 100 according to an embodiment of the present application. The access management function network element includes a processor 101, a memory 102, and one or more programs, wherein the one or more programs Are stored in the memory 102, and when the one or more programs are executed by the processor 101, the access management function network element is caused to perform the following steps: receiving a registration request message sent by a terminal device, and The registration request message is used for the terminal device to request registration to a network belonging to a preset public land mobile communication network PLMN;

Determining a first parameter, where the first parameter indicates the maximum number of packet data unit PDU sessions that the terminal device supports to establish under the preset PLMN;

Save the first parameter;

Send a first message to the terminal device, where the first message carries the first parameter.

The access management function network element 100 completely corresponds to the access management function network element in the method embodiment, and the access management function network element 100 is used to execute the method embodiment shown in FIGS. 3-10. The corresponding steps performed by the meta.

Wherein, when the one or more programs are executed by the processor 101, the access management function network element 100 executes the steps sent in the method embodiment. For example, step 220 of sending the first message to the terminal device in FIG. 3 is performed. It also executes the steps implemented or processed inside the access management function network element in the method embodiment. For example, step 221 of determining the first parameter in FIG. 3 is performed. And perform the steps of access management function network element storage in the method embodiment. For example, step 222 of saving the first parameter in FIG. 3 is executed.

The access management function network element 100 further includes a transceiver 103, where instructions or programs are stored in the memory 102; the processor 101 is configured to execute instructions or programs stored in the memory 102, and the transceiver 103 is configured to perform transceiving operations.

14 is a schematic block diagram of a data management network element 200 provided by an embodiment of the present application. The data management network element includes a processor 201, a memory 202, and one or more programs, wherein the one or more programs are stored in the In the memory 202, when the one or more programs are executed by the processor 201, the data management network element is caused to perform the following steps: receiving a query message sent by an access management function network element, and the query message is used When querying the first parameter, the first parameter indicates the maximum number of packet data unit PDU sessions that the terminal device under the preset public land mobile communication network PLMN supports;

Send a feedback message to the access management function network element, where the feedback message carries the first parameter.

The data management network element 200 completely corresponds to the data management network element in the method embodiment, and the data management network element 200 is used to execute the corresponding steps performed by the data management network element in the method embodiment shown in FIG. 3 to FIG. 10.

Wherein, when the one or more programs are executed by the processor 201, the data management network element 200 executes the steps sent in the method embodiment. For example, step 213 of sending a feedback message to the access management function network element in FIG. 3 is performed. The data management network element 200 further includes a transceiver 203, where instructions or programs are stored in the memory 202; the processor 203 is configured to execute instructions or programs stored in the memory 202; and the transceiver 203 is configured to perform transceiving operations.

This embodiment also provides a computer storage medium in which computer instructions are stored. When the computer instructions run on a terminal device, the terminal device is caused to execute the above-mentioned related method steps to implement the session establishment in the above-mentioned embodiment. Methods.

This embodiment also provides a computer program product, which when the computer program product runs on a computer, causes the computer to execute the above-mentioned related steps to implement the method for session establishment in the above-mentioned embodiment.

In addition, the embodiments of the present application also provide a communication device. The device may specifically be a chip, component, or module. The device may include a connected processor and a memory; wherein the memory is used to store computer execution instructions, and when the device is running The processor can execute the computer-executable instructions stored in the memory, so that the chip executes the method for session establishment in the foregoing method embodiments.

It should be understood that the processor mentioned in the embodiments of the present invention may be a central processing unit (central processing unit, CPU), or may also be other general-purpose processors, digital signal processors (digital signal processors, DSP), and application-specific integrated circuits ( application specific integrated circuit (ASIC), ready-made programmable gate array (field programmable gate array, FPGA) or other programmable logic devices, discrete gates or transistor logic devices, discrete hardware components, etc. The general-purpose processor may be a microprocessor or the processor may also be any conventional processor or the like.

It should also be understood that the memory mentioned in the embodiments of the present invention may be a volatile memory or a non-volatile memory, or may include both volatile and non-volatile memory. Among them, the non-volatile memory can be read-only memory (ROM), programmable read-only memory (programmable ROM, PROM), erasable programmable read-only memory (erasable PROM, EPROM), and electrically available Erase programmable read-only memory (electrically EPROM, EEPROM) or flash memory. The volatile memory may be random access memory (RAM), which is used as an external cache. By way of exemplary but not restrictive description, many forms of RAM are available, such as static random access memory (static RAM, SRAM), dynamic random access memory (dynamic RAM, DRAM), synchronous dynamic random access memory (synchronous DRAM, SDRAM), double data rate synchronous dynamic random access memory (double data rate SDRAM, DDR SDRAM), enhanced synchronous dynamic random access memory (enhanced SDRAM, ESDRAM), synchronous connection dynamic random access memory (synchlink DRAM, SLDRAM) ) And direct memory bus random access memory (direct rambus RAM, DR RAM).

It should be noted that when the processor is a general-purpose processor, DSP, ASIC, FPGA or other programmable logic device, discrete gate or transistor logic device, or discrete hardware component, the memory (storage module) is integrated in the processor.

It should be noted that the memories described herein are intended to include, but are not limited to, these and any other suitable types of memories.

A person of ordinary skill in the art may be aware that the units and algorithm steps of the examples described in combination with the embodiments disclosed herein can be implemented by electronic hardware or a combination of computer software and electronic hardware. Whether these functions are performed by hardware or software depends on the specific application and design constraint conditions of the technical solution. Professionals and technicians can use different methods for each specific application to implement the described functions, but such implementation should not be considered beyond the scope of this application.

Those skilled in the art can clearly understand that, for the convenience and conciseness of the description, the specific working process of the above-described system and device may refer to the corresponding process in the foregoing method embodiment, which will not be repeated here.

In the several embodiments provided in this application, it should be understood that the disclosed system, device, and method may be implemented in other ways. For example, the device embodiments described above are merely illustrative. For example, the division of the units is only a logical function division, and there may be other divisions in actual implementation, for example, multiple units or components may be combined or It can be integrated into another system, or some features can be ignored or not implemented. In addition, the displayed or discussed mutual coupling or direct coupling or communication connection may be indirect coupling or communication connection through some interfaces, devices or units, and may be in electrical, mechanical or other forms.

The units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they may be located in one place, or they may be distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the objectives of the solutions of the embodiments.

In addition, the functional units in the various embodiments of the present application may be integrated into one processing unit, or each unit may exist alone physically, or two or more units may be integrated into one unit.

If the function is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer readable storage medium. Based on this understanding, the technical solution of this application essentially or the part that contributes to the existing technology or the part of the technical solution can be embodied in the form of a software product, and the computer software product is stored in a storage medium, including Several instructions are used to make a computer device (which may be a personal computer, a server, or a network device, etc.) execute all or part of the steps of the method described in each embodiment of the present application. The aforementioned storage media include: U disk, mobile hard disk, read-only memory (read-only memory, ROM), random access memory (random access memory, RAM), magnetic disk or optical disk and other media that can store program code .

The above are only specific implementations of this application, but the protection scope of this application is not limited to this. Any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed in this application. Should be covered within the scope of protection of this application. Therefore, the protection scope of this application should be subject to the protection scope of the claims.

Claims

A method for session establishment, characterized in that it includes:

The terminal device sends a registration request message to the network side, where the registration request message is used to request registration to a network belonging to a preset public land mobile communication network PLMN;

The terminal device receives a first message, the first message carries a first parameter, and the first parameter indicates the maximum number of packet data unit PDU sessions that the terminal device supports to establish under the preset PLMN.
The method of claim 1, wherein the method further comprises:

The terminal device sets the minimum of the maximum number of PDU sessions supported by the terminal device under the preset PLMN, the number of PDU session identifiers defined by the protocol, and the maximum number of PDU sessions actually supported by the terminal device. Determining the maximum number of PDU sessions allowed to be established by the terminal device;

The terminal device establishes a PDU session according to the maximum number of PDU sessions allowed by the terminal device to be established.
The method according to claim 2, wherein the terminal device establishes a PDU session according to the maximum number of PDU sessions allowed by the terminal device to establish:

When the number of PDU sessions that the terminal device has established is equal to the maximum number of PDU sessions that the terminal device is allowed to establish, the terminal device refuses to establish the PDU session, or the terminal device releases the established PDU After any PDU session in the session, the PDU session is established.
The method according to any one of claims 1 to 3, wherein the first message is a registration reception message, and the registration reception message is used to indicate that the terminal device is successfully registered.
The method according to claim 4, wherein before the terminal device sends a registration request message to the network side, the method further comprises:

The terminal device is switched from the first communication system to the second communication system, wherein the number of PDU sessions established by the terminal device in the first communication system is M, and M is a positive integer.
The method of claim 5, wherein the method further comprises:

When a different system switching interface exists between the first communication system and the second communication system, the registration request message carries first status indication information, and the first status indication information is used to indicate the M-way PDU The state after the session is transferred to the second communication system;

The registration reception message carries second status indication information, where the second status indication information is used to indicate the active N PDU sessions in the M PDU session, and N is a positive integer less than or equal to M;

The terminal device determines that the N-way PDU session is in the active state according to the second state indication information.
The method of claim 5, wherein the method further comprises:

When there is no different system switching interface between the first communication system and the second communication system, the terminal device determines that the M-channel PDU session can be used in the M-channel PDU session according to the maximum number of PDU sessions allowed to be established by the terminal device For N PDU sessions established in the second communication system, the N is a positive integer less than or equal to M.
The method according to any one of claims 1-3, wherein the first message is a PDU session establishment rejection message, and the PDU session establishment rejection message is used to refuse to establish a PDU session. Before receiving the first message, the method further includes:

The terminal device sends at least one PDU session establishment request message to the network side.
8. The method according to any one of claims 1-8, wherein the method further comprises:

The terminal device receives an update message, the update message carries a second parameter, and the second parameter is a parameter after the first parameter changes.
The method according to any one of claims 1-9, wherein the maximum number of PDU sessions supported by the terminal device under the preset PLMN is an operator based on the subscription data of the terminal device, which is The terminal equipment is customized.
A method for session establishment, characterized in that it includes:

The access management function network element receives a registration request message sent by a terminal device, where the registration request message is used by the terminal device to request registration to a network belonging to a preset public land mobile communication network PLMN;

Determining, by the access management function network element, a first parameter, the first parameter indicating the maximum number of packet data unit PDU sessions that the terminal device supports to establish under the preset PLMN;

Storing the first parameter by the access management function network element;

The access management function network element sends a first message to the terminal device, where the first message carries the first parameter.
The method according to claim 11, wherein the registration request message carries first status indication information, and the first status indication information is used to indicate the status of an M-channel PDU session, wherein the M-channel PDU The session is the number of PDU sessions established by the terminal device in the first communication system and transferred to the second communication system when the terminal device switches from the first communication system to the second communication system;

The method also includes:

Determining, by the access management function network element, the N PDU sessions in the active state among the M PDU sessions according to the first parameter;

The first message is a registration reception message, and the registration reception message carries second status indication information. The second status indication information is used for the N-way PDU session, M is a positive integer, and N is less than or equal to M A positive integer.
The method according to claim 11 or 12, wherein the access management function network element determining the first parameter comprises:

Sending, by the access management function network element, a query message to the data management network element, where the query message is used to query the first parameter;

The access management function network element receives a feedback message sent by the data management network element, where the feedback message includes the first parameter; or,

The access management function network element determines the first parameter based on a local policy.
The method according to any one of claims 11-13, wherein the method further comprises:

The access management network element sends an update message to the terminal device, where the update message carries a second parameter, and the second parameter is a parameter after the first parameter changes.
A method for session establishment, characterized in that it includes:

The data management network element receives a query message sent by the access management function network element, where the query message is used to query a first parameter, and the first parameter indicates the largest group supported by the terminal device under the preset public land mobile communication network PLMN. Number of data unit PDU sessions;

The data management network element sends a feedback message to the access management function network element, and the feedback message carries the first parameter.
A terminal device, characterized by comprising: one or more processors; a memory; and one or more programs, wherein the one or more programs are stored in the memory, when the one or more When the program is executed by the processor, the terminal device is caused to execute the following steps:

Sending a registration request message to the network side, where the registration request message is used to request registration to a network belonging to a preset public land mobile communication network PLMN;

A first message is received, where the first message carries a first parameter, and the first parameter indicates the maximum number of packet data unit PDU sessions that the terminal device supports to establish under the preset PLMN.
The terminal device according to claim 16, wherein when the one or more programs are executed by the processor, the terminal device is caused to perform the following steps:

The minimum of the maximum number of PDU sessions supported by the terminal device under the preset PLMN, the number of PDU session identifiers defined by the protocol, and the maximum number of PDU sessions actually supported by the terminal device is determined as the The maximum number of PDU sessions allowed to be established by the terminal device;

Establish a PDU session according to the maximum number of PDU sessions allowed to be established by the terminal device.
The terminal device of claim 17, wherein, according to the maximum number of PDU sessions allowed to be established by the terminal device, establishing a PDU session comprises:

When the number of PDU sessions that the terminal device has established is equal to the maximum number of PDU sessions that the terminal device is allowed to establish, the terminal device refuses to establish the PDU session, or the terminal device releases the established PDU After any PDU session in the session, the PDU session is established.
The terminal device according to any one of claims 16-18, wherein the first message is a registration reception message, and the registration reception message is used to indicate that the terminal device is successfully registered.
The terminal device according to claim 19, wherein, before sending the registration request message to the network side, when the one or more programs are executed by the processor, the terminal device is caused to perform the following steps:

Switching from the first communication system to the second communication system, wherein the number of PDU sessions established by the terminal device in the first communication system is M, and M is a positive integer.
The terminal device according to claim 20, wherein when a different system switching interface exists between the first communication system and the second communication system, the registration request message carries first status indication information, so The first state indication information is used to indicate the state of the M-channel PDU session after it is transferred to the second communication system;

The registration reception message carries second status indication information, where the second status indication information is used to indicate the active N PDU sessions in the M PDU session, and N is a positive integer less than or equal to M;

When the one or more programs are executed by the processor, the terminal device is caused to execute the following steps:

The terminal device determines that the N-way PDU session is in the active state according to the second state indication information.
The terminal device according to claim 20, wherein when there is no different system switching interface between the first communication system and the second communication system,

When the one or more programs are executed by the processor, the terminal device is caused to execute the following steps:

Determine the N PDU sessions that can be established in the second communication system among the M PDU sessions according to the maximum number of PDU sessions allowed to be established by the terminal device, where N is a positive integer less than or equal to M.
The terminal device according to any one of claims 16-18, wherein the first message is a PDU session establishment rejection message, and the PDU session establishment rejection message is used to refuse to establish a PDU session, when the one Or when multiple programs are executed by the processor, the terminal device is caused to execute the following steps:

At least one PDU session establishment request message is sent to the network side.
The terminal device according to any one of claims 16-23, wherein when the one or more programs are executed by the processor, the terminal device is caused to perform the following steps:

An update message is received, the update message carries a second parameter, and the second parameter is a parameter after the first parameter changes.