Communication system, communication method and communication device

Abstract

The present application provides a communication system, a communication method, and a communication device. The communication system is deployed in a first network, and the first network and the second network communicate with each other through a communication interface; the communication system includes: a first control plane device and a first communication device. When the second control plane device provides services to the terminal device, the first control plane device is used to forward the control plane signaling of the terminal device transmitted between the first communication device and the second control plane device, and the second control plane device is used to provide control plane functions for the above-mentioned terminal device, wherein the second control plane device is a device deployed in the second network; when the second control plane device no longer provides services to the terminal device, the first control plane device is used to transmit control plane signaling between the first communication device, and the first control plane device is also used to provide control plane functions for the above-mentioned terminal device. Through this application, the network can provide services to users.

Description

Technical Field

[0001] The present application relates to the field of communications, and more particularly, to a communication system, a communication method, and a communication device. Background Art

[0002] Currently, more and more enterprises are demanding independent network construction. One possible deployment method for enterprise private networks is public network integrated non-public network (PNI-NPN). Specifically, the public land mobile network (PLMN) deploys dedicated network slices for enterprises. Taking into account the localized nature of enterprise services, user plane function (UPF) network elements are deployed in enterprise campuses, and control plane network elements are deployed in operator core nodes (such as city-level computer rooms). The public network and the enterprise private network communicate through network interfaces to jointly provide services to users.

[0003] The network interface between the public network and the enterprise private network may fail, which may cause the PNI-NPN to be unable to serve its users. Once the user is disconnected from the PNI-NPN, the user's current business will be interrupted, causing significant losses to the enterprise's product line. Summary of the Invention

[0004] The present application provides a communication system, a communication method, and a communication device, which enable a network to provide services to users.

[0005] In a first aspect, a communication system is provided. The communication system is deployed in a first network, and the first network and a second network communicate via a communication interface. The communication system includes: a first control plane device and a first communication device. When the second control plane device provides services for a terminal device, the first control plane device is configured to forward control plane signaling of the terminal device transmitted between the first communication device and the second control plane device, and the second control plane device is configured to provide control plane functions for the terminal device, wherein the second control plane device is a device deployed in the second network. When the second control plane device no longer provides services for the terminal device, the first control plane device is configured to transmit control plane signaling to and from the first communication device, and the first control plane device is further configured to provide control plane functions for the terminal device.

[0006] In one example, the situation where the second control plane provides services to the terminal device may include: the situation where the above-mentioned communication interface connection is normal; correspondingly, the situation where the second control plane no longer provides services to the terminal device may include: the situation where the above-mentioned communication interface connection fails.

[0007] As another example, the situation where the second control plane provides services to the terminal device may include: the situation where the security and privacy of the terminal device's business is low; correspondingly, the situation where the second control plane no longer provides services to the terminal device may include: the situation where the security and privacy of the terminal device's business is high.

[0008] As another example, the situation where the second control plane provides services to the terminal device may include: the situation where the second network is not congested; accordingly, the situation where the second control plane no longer provides services to the terminal device may include: the situation where the second network is congested. Alternatively, the situation where the second control plane provides services to the terminal device may include: the situation where the first network is congested; accordingly, the situation where the second control plane no longer provides services to the terminal device may include: the situation where the first network is not congested.

[0009] Based on the above solution, by deploying a first control plane device on the first network, when the second control plane device provides services to the terminal device, the first control plane device can act as a proxy device (or proxy node) between the first communication device and the second control plane device, forwarding signaling between the first communication device and the second control plane device. When the second control plane device no longer provides services to the terminal device, the first control plane device can perform control plane functions to control the terminal device. This enables the network to provide services to users, thereby ensuring the stability of user services as much as possible and achieving user service continuity. Taking the communication interface as an example, when the communication interface between two networks (such as the first network and the second network) is connected normally, the first control plane device can act as a proxy device (or proxy node) between the first communication device and the second control plane device, forwarding signaling between the first communication device and the second control plane device. When the communication interface between the first network and the second network fails, the first control plane device can perform control plane functions to control the terminal device, preventing the terminal device from being unable to connect to the first network after the communication interface between the first network and the second network fails. Therefore, not only will the normal communication between the first communication device and the second control plane device not be affected when the communication interface connection between the first network and the second network is normal, but also when the communication interface connection between the first network and the second network fails, the business of the terminal device can continue to operate normally.

[0010] In combination with the first aspect, in some implementations of the first aspect, when the second control plane device provides services for the terminal device, the first control plane device is further configured to obtain an association identifier of the terminal device.

[0011] Based on the above solution, the second control plane device obtains the terminal device's association identifier when providing services to the terminal device. Therefore, after the second control plane device no longer provides services to the terminal device, it can identify the terminal device's signaling based on the terminal device's association identifier to provide services to the terminal device. Furthermore, identifying the terminal device's signaling based on the terminal device's association identifier is simple and easy.

[0012] In combination with the first aspect, in some implementations of the first aspect, the first control plane device is further used to obtain the association identifier of the above-mentioned terminal device, including: the first control plane device is used to receive the association identifier of the terminal device from the second control plane device.

[0013] Based on the above solution, the first control plane device can obtain the association identifier of the terminal device from the second control plane device when the second control plane device provides services for the terminal device. The first control plane device does not need to generate or establish the association identifier of the terminal device, and the requirements for the first control plane device are not high.

[0014] In combination with the first aspect, in certain implementations of the first aspect, when the second control plane device provides services for the terminal device, the first control plane device is further used to receive a first message from the second control plane device; the first control plane device is further used to save the context information of the terminal device based on the above-mentioned first message, wherein the context information of the terminal device is associated with the association identifier of the terminal device.

[0015] Based on the above scheme, the first control plane device saves the context information of the terminal device, and the context information of the terminal device has an association relationship with the association identifier of the terminal device, so that the first control plane device can quickly obtain the context information of the terminal device based on the association identifier of the terminal device and the association relationship between the context information of the terminal device and the association identifier of the terminal device.

[0016] In combination with the first aspect, in certain implementations of the first aspect, when the second control plane device no longer provides services for the terminal device, the method also includes: the first control plane device is further used to obtain the context information of the above-mentioned terminal device through the association identifier of the terminal device.

[0017] Based on the above solution, after the second control plane device no longer provides services for the terminal device, it can quickly obtain the context information of the terminal device based on the association identifier of the terminal device and the association relationship between the context information of the terminal device and the association identifier of the terminal device to maintain normal business operation.

[0018] In combination with the first aspect, in certain implementations of the first aspect, the associated identifier of the terminal device is any one of the following: a user permanent identifier, a globally unique temporary identifier, a dedicated identifier, and an N3 tunnel identifier.

[0019] In combination with the first aspect, in certain implementations of the first aspect, the first communication device includes a source access network device, and the communication system also includes a target access network device. When the second control plane device no longer provides services for the terminal device, the first control plane device is also used to switch the terminal device from the source access network device to the target access network device.

[0020] Based on the above solution, the first control plane device can execute the switching process for the terminal device, thereby avoiding as much as possible the situation where the terminal device is unable to switch from the source access network device to the target access network device after the second control plane device no longer provides services for the terminal device.

[0021] In combination with the first aspect, in certain implementations of the first aspect, the first communication device also includes a user plane functional network element and a first control plane device, and is also used to switch the terminal device from the source access network device to the target access network device, including: a first control plane device, used to receive a switching request message from the target access network device, the switching request message including the N3 tunnel information allocated by the target access network device to the terminal device; a first control plane device, used to obtain an association identifier of the terminal device; and the first control plane device, used to send the above-mentioned N3 tunnel information to the user plane functional network element based on the association identifier of the above-mentioned terminal device.

[0022] In combination with the first aspect, in some implementations of the first aspect, the first control plane device includes a first mobility management network element and a first session management network element; the first control plane device is used to obtain the association identifier of the terminal device, including: the first mobility management network element is used to obtain the association identifier of the terminal device and send the association identifier of the terminal device to the first session management network element; the first session management network element is used to receive the association identifier of the terminal device from the first mobility management network element; the first control plane device is used to send N3 tunnel information to the user plane function network element based on the association identifier of the terminal device, including: the first session management network element is used to obtain the context information of the terminal device according to the association identifier of the terminal device, and send a session modification request message to the user plane function network element, and the session modification request message includes the N3 tunnel information.

[0023] In combination with the first aspect, in certain implementations of the first aspect, when the second control plane device no longer provides services for the terminal device, if the second control plane device resumes providing services for the terminal device, the first control plane device is also used to trigger a path switching process for the terminal device so that the terminal device establishes a communication connection with the second control plane device.

[0024] In combination with the first aspect, in certain implementations of the first aspect, the first control plane device is used to provide control plane functions for the terminal device based on security parameters, where the security parameters are security parameters when the above-mentioned second control plane device provides control plane functions for the terminal device.

[0025] Based on the above solution, the first control plane device does not need to generate new security parameters (such as intermediate keys) for the terminal device. Therefore, not only can the first control plane device provide control plane functions for the terminal device when the second control plane device no longer provides services for the terminal device, but the requirements for the first control plane device can also be reduced, and the changes to the existing protocol are minimal.

[0026] In combination with the first aspect, in some implementations of the first aspect, the first control plane device includes: a first mobility management network element and / or a first session management network element.

[0027] In combination with the first aspect, in some implementations of the first aspect, the first network is a local network in which a public network is integrated with a non-public network, and the second network is a central network in which a public network is integrated with a non-public network.

[0028] In combination with the first aspect, in certain implementations of the first aspect, the above-mentioned communication interface includes an N2 interface and / or an N4 interface.

[0029] In combination with the first aspect, in certain implementations of the first aspect, the first communication device includes a user plane function network element. When the second control plane device no longer provides services for the terminal device, if the second control plane device resumes providing services for the terminal device, the user plane function network element provides user plane functions for the terminal device based on the N3 tunnel identifier, and the N3 tunnel identifier is the previous identifier.

[0030] Based on the above solution, when the second control plane device no longer provides services for the terminal device, if the second control plane device resumes providing services for the terminal device, the user plane function network element can provide user plane functions for the terminal device based on the original N3 tunnel identifier, so that the first session management network element in the first control plane device does not need to perform a session modification process with the user plane function network element, or the first session management network element does not need to send the N3 tunnel identifier to the user plane function network element when performing a session modification process with the user plane function network element.

[0031] In a second aspect, a communication method is provided. The method includes: when a second control plane device deployed in a second network provides services for a terminal device, a first control plane device deployed in a first network forwards control plane signaling of the terminal device transmitted between a first communication device and the second control plane device deployed in the first network, and the second control plane device is used to provide control plane functions for the terminal device; when the second control plane device no longer provides services for the terminal device, control plane signaling is transmitted between the first control plane device and the first communication device, and the first control plane device provides control plane functions for the terminal device.

[0032] Based on the above solution, by deploying a first control plane device on the first network, when the second control plane device provides services to the terminal device, the first control plane device can act as a proxy device (or proxy node) between the first communication device and the second control plane device, forwarding signaling between the first communication device and the second control plane device. When the second control plane device no longer provides services to the terminal device, the first control plane device can perform control plane functions to control the terminal device. This enables the network to provide services to users, thereby ensuring the stability of user services as much as possible and achieving user service continuity. Taking the communication interface as an example, when the communication interface between two networks (such as the first network and the second network) is connected normally, the first control plane device can act as a proxy device (or proxy node) between the first communication device and the second control plane device, forwarding signaling between the first communication device and the second control plane device. When the communication interface between the first network and the second network fails, the first control plane device can perform control plane functions to control the terminal device, preventing the terminal device from being unable to connect to the first network after the communication interface between the first network and the second network fails. Therefore, not only will the normal communication between the first communication device and the second control plane device not be affected when the communication interface connection between the first network and the second network is normal, but also when the communication interface connection between the first network and the second network fails, the business of the terminal device can continue to operate normally.

[0033] In combination with the second aspect, in some implementations of the second aspect, when the second control plane device provides services for the terminal device, the method further includes: the first control plane device obtains an association identifier of the terminal device.

[0034] In combination with the second aspect, in some implementations of the second aspect, the first control plane device obtains the association identifier of the terminal device, including: the first control plane device receives the association identifier of the terminal device from the second control plane device.

[0035] In combination with the second aspect, in certain implementations of the second aspect, when the second control plane device provides services for the terminal device, the method also includes: the first control plane device receives a first message from the second control plane device; the first control plane device saves the context information of the terminal device based on the first message, wherein the context information of the terminal device is associated with the association identifier of the terminal device.

[0036] In combination with the second aspect, in some implementations of the second aspect, when the second control plane device no longer provides services for the terminal device, the method further includes: the first control plane device obtains the context information of the terminal device through the association identifier of the terminal device.

[0037] In combination with the second aspect, in certain implementations of the second aspect, the associated identifier of the terminal device is any one of the following: a user permanent identifier, a globally unique temporary identifier, a dedicated identifier, and an N3 tunnel identifier.

[0038] In combination with the second aspect, in certain implementations of the second aspect, the first communication device includes a source access network device, the first network also includes a target access network device, and when the second control plane device no longer provides services for the terminal device, the method also includes: the first control plane device switches the terminal device from the source access network device to the target access network device.

[0039] In combination with the second aspect, in certain implementations of the second aspect, the first communication device also includes a user plane functional network element, and the first control plane device switches the terminal device from the source access network device to the target access network device, including: the first control plane device receives a switching request message from the target access network device, the switching request message includes the N3 tunnel information allocated by the target access network device to the terminal device; the first control plane device obtains the association identifier of the terminal device; the first control plane device sends the N3 tunnel information to the user plane functional network element based on the association identifier of the terminal device.

[0040] In combination with the second aspect, in some implementations of the second aspect, the first control plane device includes a first mobility management network element and a first session management network element; the first control plane device obtains the association identifier of the terminal device, including: the first mobility management network element obtains the association identifier of the terminal device and sends the association identifier of the terminal device to the first session management network element; the first session management network element receives the association identifier of the terminal device from the first mobility management network element; the first control plane device sends N3 tunnel information to the user plane function network element based on the association identifier of the terminal device, including: the first session management network element obtains the context information of the terminal device according to the association identifier of the terminal device, and sends a session modification request message to the user plane function network element, and the session modification request message includes the N3 tunnel information.

[0041] In combination with the second aspect, in certain implementations of the second aspect, the method also includes: when the second control plane device no longer provides services for the terminal device, if the second control plane device resumes providing services for the terminal device, the first control plane device triggers a path switching process for the terminal device so that the terminal device is connected to the second control plane device.

[0042] In combination with the second aspect, in certain implementations of the second aspect, the method also includes: the first control plane device provides a control plane function for the terminal device based on a security parameter, and the security parameter is a security parameter when the above-mentioned second control plane device provides the control plane function for the terminal device.

[0043] Based on the above solution, the first control plane device does not need to generate new security parameters (such as intermediate keys) for the terminal device. Therefore, not only can the first control plane device provide control plane functions for the terminal device when the second control plane device no longer provides services for the terminal device, but the requirements for the first control plane device can also be reduced, and the changes to the existing protocol are minimal.

[0044] In combination with the second aspect, in some implementations of the second aspect, the first control plane device includes: a first mobility management network element and / or a first session management network element.

[0045] In combination with the second aspect, in some implementations of the second aspect, the first network is a local network in which a public network integrates a non-public network, and the second network is a central network in which the public network integrates a non-public network.

[0046] In combination with the second aspect, in certain implementations of the second aspect, the above-mentioned communication interface includes an N2 interface and / or an N4 interface.

[0047] In a third aspect, a communication method is provided. The method may be executed by a network device, or by a component of the network device (e.g., a chip or circuit), without limitation. For ease of description, the method is described below using execution by a first mobility management network element as an example.

[0048] The method includes: a first mobility management network element obtains an association identifier of a terminal device, where the association identifier of the terminal device is used to identify the terminal device when a second control plane device deployed in a second network no longer provides services for the terminal device; the first mobility management network element sends the association identifier of the terminal device to a first session management network element; wherein the first mobility management network element and the first session management network element are deployed in the first network.

[0049] Based on the above solution, by deploying the first mobility management network element in the first network, the first mobility management network element sends the association identifier of the terminal device to the first session management network element. The association identifier of the terminal device is used to identify the above terminal device when the second control plane device no longer provides services for the terminal device. Therefore, when the second control plane device no longer provides services for the terminal device, the first mobility management network element and the first session management network element can identify the signaling of the terminal device based on the association identifier of the terminal device, so that when the second control plane device no longer provides services for the terminal device, the terminal device's business can continue to operate normally.

[0050] In combination with the third aspect, in certain implementations of the third aspect, when the second control plane device provides services for the terminal device, the method also includes: the first mobile management network element receives an association identifier of the terminal device from the second mobile management network element, and the second mobile management network element is deployed in the second network.

[0051] Based on the above solution, the first mobile management network element can obtain the association identifier of the terminal device from the second mobile management network element when the second control plane device provides services for the terminal device. The first mobile management network element does not need to generate or establish the association identifier of the terminal device, and the requirements for the first mobile management network element are not high.

[0052] In combination with the third aspect, in certain implementations of the third aspect, when the second control plane device provides services for the terminal device, the method also includes: the first mobility management network element receives a first message from the second mobility management network element; the first mobility management network element saves the context information of the terminal device based on the first message, and the context information of the terminal device is associated with the association identifier of the terminal device.

[0053] Based on the above scheme, the first mobile management network element saves the context information of the terminal device, and the context information of the terminal device has an association relationship with the association identifier of the terminal device. In this way, the first mobile management network element can quickly obtain the context information of the terminal device based on the association identifier of the terminal device and the association relationship between the context information of the terminal device and the association identifier of the terminal device.

[0054] In combination with the third aspect, in certain implementations of the third aspect, the first mobility management network element obtains the association identifier of the terminal device, including: when the second control plane device no longer provides services for the terminal device, the first mobility management network element identifies the context of the terminal device based on the control plane port identifier, wherein the control plane port identifier is the port identifier of the control plane interface between the first mobility management network element and the access network device; the first mobility management network element obtains the association identifier of the terminal device based on the context of the terminal device.

[0055] In combination with the third aspect, in certain implementations of the third aspect, the method also includes: when the second control plane device no longer provides services for the terminal device, if the second control plane device resumes providing services for the terminal device, the first mobility management network element triggers a path switching process for the terminal device so that the terminal device establishes a communication connection with the second session management network element and / or the second mobility management network element, wherein the second session management network element and the second mobility management network element are deployed in the second network.

[0056] In combination with the third aspect, in certain implementations of the third aspect, the method also includes: the first mobile management network element provides a control plane function for the terminal device based on a security parameter, and the security parameter is the security parameter when the above-mentioned second mobile management network element provides the control plane function for the terminal device.

[0057] Based on the above solution, the first mobile management network element does not need to generate new security parameters (such as intermediate keys) for the terminal device. Therefore, not only can the first mobile management network element provide control plane functions for the terminal device when the second control plane device no longer provides services for the terminal device, but the requirements for the first mobile management network element can also be reduced, and the changes to the existing protocol are minimal.

[0058] In combination with the third aspect, in certain implementations of the third aspect, the associated identifier of the terminal device is any one of the following: a user permanent identifier, a globally unique temporary identifier, a dedicated identifier, and an N3 tunnel identifier.

[0059] In a fourth aspect, a communication method is provided. The method may be executed by a network device, or by a component of the network device (e.g., a chip or circuit), without limitation. For ease of description, the method is described below using execution by a first session management network element as an example.

[0060] The method includes: a first session management network element receives an association identifier of a terminal device from a first mobility management network element, where the association identifier of the terminal device is used to identify the terminal device when a second control plane device deployed in a second network no longer provides services for the terminal device; when the second control plane device no longer provides services for the terminal device, the first session management network element identifies a session context associated with the association identifier of the terminal device based on the association identifier of the terminal device; wherein the first session management network element and the first mobility management network element are deployed in the first network.

[0061] Based on the above solution, by deploying a first session management network element in the first network, the first session management network element receives the association identifier of the terminal device from the first mobility management network element. The association identifier of the terminal device is used to identify the above terminal device when the second control plane device no longer provides services for the terminal device. Therefore, when the second control plane device no longer provides services for the terminal device, the first session management network element can identify the session context associated with the association identifier of the terminal device based on the association identifier of the terminal device, so that when the second control plane device no longer provides services for the terminal device, the terminal device's business can continue to operate normally.

[0062] In combination with the fourth aspect, in certain implementations of the fourth aspect, when the second control plane device provides services for the terminal device, the method also includes: the first session management network element receives the association identifier of the terminal device from the second session management network element, and the second mobility management network element is deployed in the second network.

[0063] In combination with the fourth aspect, in certain implementations of the fourth aspect, when the second control plane device provides services for the terminal device, the method also includes: the first session management network element receives a first message from the second session management network element, and the second session management network element is deployed in the second network; the first session management network element saves the context information of the terminal device based on the first message, and the context information of the terminal device is associated with the association identifier of the terminal device.

[0064] Based on the above scheme, the first session management network element saves the context information of the terminal device, and the context information of the terminal device has an association relationship with the association identifier of the terminal device. In this way, the first session management network element can quickly obtain the context information of the terminal device based on the association identifier of the terminal device and the association relationship between the context information of the terminal device and the association identifier of the terminal device.

[0065] In combination with the fourth aspect, in certain implementations of the fourth aspect, when the second control plane device no longer provides services for the terminal device, the method also includes: the first session management network element obtains the context information of the terminal device based on the association identifier of the terminal device, and sends a session modification request message to the user plane function network element.

[0066] In combination with the fourth aspect, in certain implementations of the fourth aspect, the associated identifier of the terminal device is any one of the following: a user permanent identifier, a globally unique temporary identifier, a dedicated identifier, and an N3 tunnel identifier.

[0067] In a fifth aspect, a communication method is provided. The method may be executed by a network device, or may be executed by a component of the network device (e.g., a chip or circuit), without limitation. For ease of description, the method is described below using execution by a second mobility management network element as an example.

[0068] The method includes: a second mobility management network element determines an association identifier of a terminal device, where the association identifier of the terminal device is used to identify the terminal device when a second control plane device deployed in a second network no longer provides services for the terminal device; the second mobility management network element sends the association identifier of the terminal device to a first mobility management network element; wherein the first mobility management network element is deployed in the first network, and the second mobility management network element is deployed in the second network.

[0069] Based on the above scheme, the second mobile management network element deployed in the second network sends the association identifier of the terminal device to the first mobile management network element deployed in the first network. The association identifier of the terminal device is used to identify the above terminal device when the second control plane device no longer provides services for the terminal device. Therefore, when the second control plane device no longer provides services for the terminal device, the first mobile management network element can identify the signaling of the terminal device based on the association identifier of the terminal device, so that when the second control plane device no longer provides services for the terminal device, the terminal device's business can continue to operate normally.

[0070] In combination with the fifth aspect, in certain implementations of the fifth aspect, the second mobility management network element determines the association identifier of the terminal device, including: if the network slice supported by the terminal device and / or the first network has robustness requirements, the second mobility management network element determines the association identifier of the terminal device.

[0071] In combination with the fifth aspect, in some implementations of the fifth aspect, the method further includes: the second mobility management network element sends an association identifier of the terminal device to a second session management network element, and the second session management network element is deployed in the second network.

[0072] In combination with the fifth aspect, in certain implementations of the fifth aspect, the associated identifier of the terminal device is any one of the following: a user permanent identifier, a globally unique temporary identifier, and a dedicated identifier.

[0073] In combination with the fifth aspect, in certain implementations of the fifth aspect, when the second control plane device no longer provides services for the terminal device, if the second control plane device resumes providing services for the terminal device, the second mobility management network element provides control plane functions for the terminal device based on security parameters, and the security parameters are the security parameters when the second mobility management network element provides control plane functions for the terminal device before the second control plane device no longer provides services for the terminal device.

[0074] In a sixth aspect, a communication method is provided. The method can be executed by a network device, or by a component of the network device (such as a chip or circuit), without limitation. For ease of description, the following description is based on an example of execution by a second session management network element.

[0075] The method includes: a second session management network element obtains an association identifier of a terminal device, where the association identifier of the terminal device is used to identify the terminal device when a second control plane device deployed in a second network no longer provides services for the terminal device; the second session management network element sends the association identifier of the terminal device to a first session management network element; wherein the first session management network element is deployed in the first network, and the second session management network element is deployed in the second network.

[0076] Based on the above solution, the second session management network element deployed in the second network sends the association identifier of the terminal device to the first session management network element deployed in the first network. The association identifier of the terminal device is used to identify the above terminal device when the second control plane device no longer provides services for the terminal device. Therefore, when the second control plane device no longer provides services for the terminal device, the first session management network element can identify the signaling of the terminal device based on the association identifier of the terminal device, so that when the second control plane device no longer provides services for the terminal device, the terminal device's business can continue to operate normally.

[0077] In combination with the sixth aspect, in certain implementations of the sixth aspect, the method also includes: if the network slice supported by the terminal device or the first network has robustness requirements, the second session management network element sends the association identifier of the terminal device to the user plane function network element, and the user plane function network element is deployed in the first network.

[0078] In combination with the sixth aspect, in certain implementations of the sixth aspect, the second session management network element obtains the association identifier of the terminal device, including: the second session management network element receives the association identifier of the terminal device from the second mobility management network element, and the second mobility management network element is deployed in the second network.

[0079] In combination with the sixth aspect, in certain implementations of the sixth aspect, the associated identifier of the terminal device is any one of the following: a user permanent identifier, a globally unique temporary identifier, and a dedicated identifier.

[0080] In a seventh aspect, a communication device is provided, the device being configured to execute the method of any possible implementation of aspects 2 to 6. Specifically, the device may include units and / or modules, such as a processing unit and / or a communication unit, for executing the method of any possible implementation of aspects 2 to 6.

[0081] In one implementation, the apparatus is a network device (e.g., a control plane device, a mobility management network element, or a session management network element). When the apparatus is a network device, the communication unit may be a transceiver or an input / output interface; and the processing unit may be at least one processor. Optionally, the transceiver may be a transceiver circuit. Optionally, the input / output interface may be an input / output circuit.

[0082] In another implementation, the apparatus is a chip, chip system, or circuit for a network device (e.g., a control plane device, a mobility management network element, or a session management network element). When the apparatus is a chip, chip system, or circuit for a network device, the communication unit may be an input / output interface, interface circuit, output circuit, input circuit, pin, or related circuit on the chip, chip system, or circuit; and the processing unit may be at least one processor, processing circuit, or logic circuit.

[0083] In an eighth aspect, a communication device is provided, comprising: at least one processor configured to execute a computer program or instruction stored in a memory to perform the method of any possible implementation of aspects 2 to 6. Optionally, the device further comprises a memory configured to store the computer program or instruction. Optionally, the device further comprises a communication interface, through which the processor reads the computer program or instruction stored in the memory.

[0084] In one implementation, the apparatus is a network device (eg, a control plane device, a mobility management network element, or a session management network element).

[0085] In another implementation, the apparatus is a chip, a chip system, or a circuit for a network device (such as a control plane device, such as a mobility management network element, such as a session management network element).

[0086] In a ninth aspect, the present application provides a processor for executing the methods provided in the above aspects.

[0087] For the operations such as sending and acquiring / receiving involved in the processor, unless otherwise specified, or if they do not conflict with their actual functions or internal logic in the relevant descriptions, they can be understood as processor output, reception, input and other operations, and can also be understood as sending and receiving operations performed by the radio frequency circuit and antenna. This application does not limit this.

[0088] In a tenth aspect, a computer-readable storage medium is provided, which stores a program code for execution by a device, wherein the program code includes a method for executing any possible implementation of the second to sixth aspects above.

[0089] In the eleventh aspect, a computer program product comprising instructions is provided, which, when run on a computer, enables the computer to execute the method in any possible implementation of the second to sixth aspects above.

[0090] In a twelfth aspect, a communication system is provided, comprising one or more of the aforementioned first mobility management network element, second mobility management network element, first session management network element, and second session management network element.

[0091] In a thirteenth aspect, a communication system is provided, comprising one or more of the aforementioned first control plane device, the second mobility management network element, and the second session management network element. BRIEF DESCRIPTION OF THE DRAWINGS

[0092] Figure 1 A schematic diagram of a network architecture applicable to an embodiment of the present application is shown.

[0093] Figure 2 A schematic diagram of a non-public network is shown.

[0094] Figure 3 A schematic diagram of a PNI-NPN is shown.

[0095] Figure 4 4 is a schematic diagram of a communication system 400 provided in an embodiment of the present application.

[0096] Figure 5 A schematic diagram of a network architecture provided according to an embodiment of the present application is shown.

[0097] Figure 6 A schematic diagram of a communication method 600 provided in an embodiment of the present application is shown.

[0098] Figure 7 A schematic flow chart of a communication method 700 provided in an embodiment of the present application is shown.

[0099] Figure 8 A schematic flow chart of a communication method 800 provided in an embodiment of the present application is shown.

[0100] Figure 9 A schematic flow chart of a communication method 900 provided in an embodiment of the present application is shown.

[0101] Figure 10 A schematic flowchart of a communication method 1000 provided in an embodiment of the present application is shown.

[0102] Figure 11 A schematic flowchart of a communication method 1100 provided in an embodiment of the present application is shown.

[0103] Figure 12 A schematic block diagram of a communication device 1200 provided in an embodiment of the present application is shown.

[0104] Figure 13 A schematic block diagram of another communication device 1300 provided in an embodiment of the present application is shown.

[0105] Figure 14 A schematic diagram of a chip system 1400 provided in an embodiment of the present application is shown. DETAILED DESCRIPTION

[0106] The technical solution in this application will be described below with reference to the accompanying drawings.

[0107] The technical solutions of the embodiments of the present application can be applied to various communication systems, such as: fifth generation (5G) or new radio (NR) systems, satellite communications, long term evolution (LTE) systems, LTE frequency division duplex (FDD) systems, LTE time division duplex (TDD) systems, etc. The technical solutions provided in the present application can also be applied to future communication systems, such as the sixth generation mobile communication system. The technical solutions of the embodiments of the present application can also be applied to device to device (D2D) communication, vehicle-to-everything (V2X) communication, machine to machine (M2M) communication, machine type communication (MTC), industrial control, intelligent transportation system (ITS), mobile broadband, multimedia and Internet of Things (IoT) communication systems or other communication systems.

[0108] To facilitate understanding of the embodiments of this application, first Figure 1 and Figure 2 A detailed description of the network architecture applicable to the embodiments of the present application is given.

[0109] As an example, Figure 1 Schematic diagram of a network architecture applicable to an embodiment of the present application is shown. Figure 1As shown, the network architecture may, for example, include but is not limited to the following: network slice selection function (NSSF) (i.e., an example of a slice management network element), authentication server function (AUSF) (i.e., an example of an authentication server function network element), unified data management (UDM) (i.e., an example of a data management network element), access and mobility management function (AMF) (i.e., an example of an access management network element), session management function (SMF) (i.e., an example of a session management network element), policy control function (PCF) (i.e., an example of a policy control network element), application function (AF) (i.e., an example of an application network element), user equipment (UE), access network (AN), user plane function (UPF) (i.e., an example of a user plane network element), data network (DN), etc.

[0110] Below Figure 1 A brief introduction is given to each network element shown in FIG.

[0111] 1. UE: may also be referred to as terminal equipment, access terminal, user unit, user station, mobile station, mobile station, remote station, remote terminal, mobile device, user terminal, terminal, wireless communication device, user agent or user device.

[0112] The terminal device can be a device that provides voice / data to users, for example, a handheld device or vehicle-mounted device with a wireless connection function. At present, some examples of terminals are: mobile phones, tablet computers, laptop computers, PDAs, mobile internet devices (MIDs), wearable devices, virtual reality (VR) devices, augmented reality (AR) devices, wireless terminals in industrial control, wireless terminals in self-driving, wireless terminals in remote medical surgery, wireless terminals in smart grids, wireless terminals in transportation safety, wireless terminals in smart cities, wireless terminals in smart homes, cellular phones, cordless phones, session initiation protocol (SIP) phones, wireless local loop (WLL) stations, personal digital assistants (PDAs), handheld devices with wireless communication capabilities, computing devices or other processing devices connected to wireless modems, wearable devices, terminal devices in 5G networks or future evolved public land mobile communication networks (PLMNs). The terminal equipment in the network (PLMN), etc., is not limited to this in the embodiments of the present application.

[0113] As an example and not a limitation, in the embodiment of the present application, the terminal device may also be a wearable device. Wearable devices may also be called wearable smart devices, which are a general term for wearable devices that are intelligently designed and developed using wearable technology for daily wear, such as glasses, gloves, watches, clothing, and shoes. A wearable device is a portable device that is worn directly on the body or integrated into the user's clothes or accessories. Wearable devices are not only hardware devices, but also achieve powerful functions through software support, data interaction, and cloud interaction. Broadly speaking, wearable smart devices include those that are fully functional, large in size, and can achieve complete or partial functions without relying on smartphones, such as smart watches or smart glasses, as well as those that only focus on a certain type of application function and need to be used in conjunction with other devices such as smartphones, such as various smart bracelets and smart jewelry for vital sign monitoring.

[0114] In addition, in the embodiments of the present application, the terminal device can also be a terminal device in an IoT system. IoT is an important part of the future development of information technology. Its main technical feature is to connect objects to the network through communication technology, thereby realizing an intelligent network of human-machine interconnection and object-to-object interconnection.

[0115] It should be noted that the terminal device and the access network device can communicate with each other using a certain air interface technology (such as NR or LTE technology). The terminal devices can also communicate with each other using a certain air interface technology (such as NR or LTE technology).

[0116] In the embodiments of the present application, the device for implementing the function of the terminal device can be the terminal device, or it can be a device that can support the terminal device to implement the function, such as a chip system or chip, which can be installed in the terminal device. In the embodiments of the present application, the chip system can be composed of a chip, or it can include a chip and other discrete devices.

[0117] 2. (Radio) Access Network (R)AN) equipment: This equipment provides access to the communications network for authorized users in a specific area. Specifically, it can include wireless network equipment in 3rd Generation Partnership Project (3GPP) networks as well as access points in non-3GPP networks. For ease of description, the term "AN" is used below.

[0118] AN equipment can adopt different wireless access technologies. There are currently two types of wireless access technologies: 3GPP access technology (for example, the wireless access technology used in the third generation (3rd generation, 3G), fourth generation (4G) or 5G systems) and non-3GPP (non-3GPP) access technology. 3GPP access technology refers to access technology that complies with 3GPP standard specifications. For example, the access network equipment in the 5G system is called the next generation NodeBase station (gNB) or RAN equipment. Non-3GPP access technologies may include air interface technologies represented by access points (APs) in wireless fidelity (WiFi), worldwide interoperability for microwave access (WiMAX), code division multiple access (CDMA), etc. AN equipment can allow terminal devices and the 3GPP core network to interconnect and communicate using non-3GPP technologies.

[0119] AN equipment is responsible for radio resource management, quality of service (QoS) management, data compression and encryption, etc. on the air interface side. AN equipment provides access services to terminal devices and forwards control signals and user data between terminal devices and the core network.

[0120] AN equipment may include, for example, but is not limited to: a macro base station, a micro base station (also known as a small station), a radio network controller (RNC), a node B (NB), a base station controller (BSC), a base transceiver station (BTS), a home base station (e.g., home evolved NodeB, or home Node B, HNB), a baseband unit (BBU), an AP in a WiFi system, a wireless relay node, a wireless backhaul node, a transmission point (TP) or a transmission and reception point (TRP), etc. It may also be a gNB or transmission point (TRP or TP) in a 5G (e.g., NR) system, one or a group (including multiple antenna panels) of antenna panels of a base station in a 5G system, or a network node constituting a gNB or transmission point, such as a distributed unit (DU), or a base station in a next-generation communication 6G system. The embodiments of the present application do not limit the specific technology and specific device form adopted by the AN equipment.

[0121] 3. Access Management NE: This element is primarily responsible for access control, mobility management, and attach and detach functions. It also serves as the anchor point for N1 signaling (i.e., signaling on the N1 interface, referred to as N1 signaling for simplicity) and N2 signaling (i.e., signaling on the N2 interface, referred to as N2 signaling for simplicity), routing N1 / N2 session management (SM) messages for the session management NE. It also maintains and manages UE status information.

[0122] In the 5G communication system, the access management network element may be AMF. In future communication systems, the access management network element may still be AMF, or may have other names, which are not limited in this application.

[0123] 4. Session management network element: mainly used for user plane network element selection, user plane network element redirection, Internet protocol (IP) address allocation for terminal devices, as well as session establishment, modification and release and QoS control.

[0124] In a 5G communication system, the session management network element may be an SMF. In future communication systems, the session management network element may still be an SMF, or may have other names, which are not limited in this application.

[0125] 5. User plane network element: This element is primarily responsible for receiving and forwarding user plane data. For example, a user plane network element can receive user plane data from a DN and send it to a terminal device via an AN. It can also receive user plane data from a terminal device via an AN and forward it to the DN.

[0126] In a 5G communication system, the user plane network element may be a UPF. In future communication systems, the user plane network element may still be a UPF, or may have other names, which are not limited in this application.

[0127] 6. Policy control network element: It is mainly used to guide the unified policy framework of network behavior and provide policy rule information for control plane network elements (such as access management network element, session management network element, etc.).

[0128] In a 4G communication system, the policy control network element may be a policy and charging rules function (PCRF). In a 5G communication system, the policy control network element may be a PCF. In future communication systems, the policy control network element may still be a PCF, or may have other names, which are not limited in this application.

[0129] 7. Application network element: Mainly used to provide services to the 3GPP network, such as interacting with the policy control network element to perform policy control.

[0130] In a 5G communication system, the application network element may be an AF. In future communication systems, the application network element may still be an AF, or may have other names, which are not limited in this application.

[0131] 8. Data Management NE: This element is primarily used for UE subscription data management, including storage and management of UE identities and UE access authorization. The data management NE also generates 3GPP authentication credentials for the UE. The data management NE also registers and maintains the NE currently serving the UE (for example, the AMF represented by AMF ID1 is the UE's current serving AMF).

[0132] In a 5G communication system, the data management network element may be a UDM. In future communication systems, unified data management may still be a UDM, or may have other names, which are not limited in this application.

[0133] 9. Data network: Operator network mainly used to provide data services to UE, such as the Internet, third-party service networks, and IP Multimedia Service (IMS) networks.

[0134] In a 5G communication system, the data network may be a DN. In future communication systems, the data network may still be a DN, or may have other names, which are not limited in this application.

[0135] 10. Authentication server functional network element: mainly used for user authentication, such as security authentication of UE when UE accesses the network.

[0136] In the 5G communication system, the authentication server may be an AUSF. In future communication systems, the authentication server function network element may still be an AUSF, or may have other names, which are not limited in this application.

[0137] 11. Slice management network element: mainly used to select a slice instance set for the UE, determine the AMF set and allowed network slice selection assistance information (NSSAIs) for the UE.

[0138] In a 5G communication system, the slice management network element may be an NSSF. In future communication systems, the slice management network element may still be an NSSF, or may have other names, which are not limited in this application.

[0139] exist Figure 1 In the network architecture shown in the figure, each network element can communicate with each other through the interfaces shown in the figure, and some interfaces can be implemented in the form of service-oriented interfaces. Figure 1 As shown, the UE and AMF can communicate through the N1 interface. The RAN and AMF can communicate through the N2 interface. The RAN and UPF can communicate through the N3 interface, which can be used to transmit user plane data, etc. The SMF and UPF can communicate through the N4 interface, which can be used to transmit information such as tunnel identification information of the N3 connection, data cache indication information, and downlink data notification messages. The relationship between other interfaces and each network element is as follows. Figure 1 For the sake of brevity, they are not described in detail here.

[0140] It should be understood that the network architecture shown above is only an exemplary illustration, and the network architecture applicable to the embodiments of the present application is not limited to this. Any network architecture that can realize the functions of the above-mentioned network elements is applicable to the embodiments of the present application.

[0141] It should also be understood that Figure 1The AMF, SMF, UPF, PCF, UDM, NSSF, AUSF, etc. shown in the specification can be understood as network elements used to implement different functions. For example, they can be combined into network slices as needed. These network elements can be independent devices, or they can be integrated into the same device to implement different functions. They can also be network elements in hardware devices, or they can be software functions running on dedicated hardware, or they can be virtualized functions instantiated on a platform (for example, a cloud platform). This application does not limit the specific form of the above network elements.

[0142] It should also be understood that the above-mentioned network elements or functions can be divided into one or more services. Furthermore, there may be services that exist independently of the network functions. In the present application, instances of the above-mentioned functions, or instances of services included in the above-mentioned functions, or service instances that exist independently of the network functions can all be referred to as service instances. In addition, in actual deployment, network elements with different functions can be co-located. For example, the access and mobility management network element can be co-located with the session management network element; the session management network element can be co-located with the user plane network element. When two network elements are co-located, the interaction between the two network elements provided in the embodiment of the present application becomes an internal operation of the co-located network element or can be omitted.

[0143] It should also be understood that the above naming is defined only to facilitate the distinction between different functions and should not constitute any limitation to this application. This application does not exclude the possibility of adopting other naming in 6G networks and other future networks. For example, in a 6G network, some or all of the above network elements may continue to use the terminology used in 5G, or may adopt other names.

[0144] It should also be understood that Figure 1 The interface names between the various network elements in the embodiment are only examples. The names of the interfaces in the specific implementation may be other names, and this application does not specifically limit this. In addition, the names of the messages (or signaling) transmitted between the above-mentioned network elements are only examples and do not constitute any limitation on the function of the messages themselves.

[0145] As an example, Figure 2 A schematic diagram of a non-public network (NPN) is shown.

[0146] Currently, more and more enterprises have the demand to build independent networks. Non-public networks are mainly used in vertical industry scenarios to serve enterprise business. Figure 2 As shown in the figure, the deployment forms of NPN include at least the following two types.

[0147] 1) Standalone NPN (SNPN): Independent of the operator's PLMN public network, providing NPN enterprise business services. SNPN can be deployed and operated by both NPN operators and PLMN operators. Figure 2 As shown in (1), in SNPN, SNPN has an independent radio access network (RAN) (such as gNB) and core network (CN) (control plane (such as SNPN CP), and user plane (such as SNPN UP)).

[0148] 2) Public network integrated NPN (PNI-NPN): A non-independent NPN that is deployed and operated by a PLMN operator. It does not require the establishment of a dedicated physical network node for the NPN. NPNs can be defined using NSSAI or data network name (DNN). Figure 2 As shown in (2), the services provided by the central network (or public network, i.e., PLMN public network) can be identified by the PLMN identifier (identify, ID) (such as PLMN A), and the services provided by the local network (or enterprise private network or PNI-NPN) can be identified by the closed access group identifier (CAG) ID (such as CAG X).

[0149] In the following, for the convenience of description, PNI-NPN is used to represent the local network (or enterprise private network), and PLMN is used to represent the central network of PNI-NPN (or public network).

[0150] It should be understood that the above two deployment methods are merely exemplary and not limiting.

[0151] To meet widely varying business needs, communication networks must be built in a flexible manner. One possible approach is to separate network functions, such as the control plane (CP) and user plane (UP) functions, and the MM and SM functions within the CP. A common technology for achieving network function separation is network slicing. Network slicing divides a physical network into multiple virtual end-to-end networks, each logically independent. Each network slice consists of an independent instantiation of a network function or combination of functions, with distinct functional characteristics and tailored to specific needs and services. This separation of network slices allows different users and user groups to flexibly and dynamically define and customize network capabilities based on their specific application scenarios and needs, without interfering with each other.

[0152] As an example, Figure 3 A schematic diagram of a PNI-NPN is shown.

[0153] like Figure 3 As shown, the PLMN deploys dedicated network slices for enterprises. Considering the localized nature of enterprise services, the UPF network elements are deployed in the enterprise campus. However, the control plane network elements (such as the AMF and SMF) remain in the operator's core nodes (such as city-level computer rooms). Network elements can be connected between the public network and the enterprise private network via interfaces. For example, the UPF network elements deployed in the enterprise campus and the SMF network elements in the PLMN communicate via the N4 interface, and the RAN (such as the gNB) deployed in the enterprise campus and the AMF network elements in the PLMN communicate via the N2 interface.

[0154] However, the physical interface between the public network and the enterprise private network may fail, for example, if the N2 interface and / or the N4 interface are disconnected. After the N2 and / or N4 interfaces are disconnected, the UE will no longer be able to connect to the network and will revert to the idle state, disconnecting the UE from the PNI-NPN. Once the UE and PNI-NPN are disconnected, the UE's ongoing services will be interrupted, causing significant losses to the factory's product line and failing to meet the service robustness requirements of non-public (or private) networks.

[0155] In view of this, an embodiment of the present application provides a solution that can maintain the normal operation of basic enterprise private network services after a connection failure occurs between the public network and the enterprise private network (such as disconnection of the N2 interface and the N4 interface).

[0156] It should be understood that the term "and / or" in this document simply describes an association between related objects, indicating that three possible relationships exist. For example, "A and / or B" can represent: A exists alone, A and B exist simultaneously, or B exists alone. Furthermore, the character " / " in this document generally indicates that the related objects are in an "or" relationship.

[0157] The various embodiments provided in this application will be described in detail below with reference to the accompanying drawings.

[0158] Figure 4 4 is a schematic diagram of a communication system 400 provided in an embodiment of the present application.

[0159] The communication system 400 is deployed in the first network. The first network and the second network communicate with each other through a communication interface. In other words, the first network and the second network are interconnected through the communication interface.

[0160] The communication system 400 includes a first control plane device 410 and a first communication device 420 .

[0161] When the second control plane device provides services for the terminal device, the first control plane device 410 is used to forward the control plane signaling of the terminal device transmitted between the first communication device 420 and the second control plane device in the second network, and the second control plane device is used to provide control plane functions for the terminal device, wherein the second control plane device is a device deployed in the second network.

[0162] When the second control plane device no longer provides services for the terminal device, the first control plane device 410 is used to transmit control plane signaling with the first communication device 420, and the first control plane device 410 is also used to provide control plane functions for the terminal device.

[0163] It can be understood that the control plane signaling used by the first control plane device 410 to forward when the second control plane device provides a service (such as a control plane service) to the terminal device, and the control plane signaling used by the first control plane device 410 to transmit between the first communication device 420 when the second control plane device no longer provides a service to the terminal device, are both general references, and this application does not limit the control plane signaling mentioned in the two places to be exactly the same. As an example, the control plane signaling mentioned in the two places can be exactly the same, completely different, or partially the same.

[0164] It can also be understood that the control plane function provided by the second control plane device for the terminal device when the second control plane device provides services to the terminal device, and the control plane function provided by the first control plane device 410 for the terminal device when the second control plane device no longer provides services to the terminal device, are both general references to the control plane functions mentioned in the two places, and this application does not limit the control plane functions mentioned in the two places to being exactly the same. As an example, the control plane functions mentioned in the two places may be exactly the same, completely different, or partially the same.

[0165] Based on the above solution, by deploying a first control plane device on the first network and the second control plane device providing services to the terminal device, the first control plane device can act as a proxy device (or proxy node) between the first communication device and the second control plane device, forwarding signaling between the first communication device and the second control plane device. When the second control plane device no longer provides services to the terminal device, the first control plane device can perform control plane functions to control the terminal device. This enables the network to provide services to users, thereby ensuring the stability of user services as much as possible and achieving user service continuity. Taking the communication interface as an example, when the communication interface between two networks (such as the first network and the second network) is connected normally, the first control plane device can act as a proxy device (or proxy node) between the first communication device and the second control plane device, forwarding signaling between the first communication device and the second control plane device. When the communication interface between the first network and the second network fails, the first control plane device can perform control plane functions to control the terminal device, preventing the terminal device from being unable to connect to the first network after the communication interface between the first network and the second network fails. Therefore, not only will the normal communication between the first communication device and the second control plane device not be affected when the communication interface connection between the first network and the second network is normal, but also when the communication interface connection between the first network and the second network fails, the business of the terminal device can continue to operate normally.

[0166] Among them, the situation where the second control plane device provides services to the terminal device, and the situation where the second control plane device no longer provides services to the terminal device, mean that in some cases, the second control plane device provides services to the terminal device, and in some cases, the second control plane device no longer provides services to the terminal device.

[0167] For example, the situation where the second control plane provides services to the terminal device may include: the situation where the aforementioned communication interface connection is normal; correspondingly, the situation where the second control plane no longer provides services to the terminal device may include: the situation where the aforementioned communication interface connection is faulty. In other words, "the situation where the second control plane provides services to the terminal device" can be replaced by "the situation where the communication interface between the first network and the second network is normal," and "the situation where the second control plane no longer provides services to the terminal device" can be replaced by "the situation where the communication interface between the first network and the second network is faulty."

[0168] For another example, the situation where the second control plane provides services to a terminal device may include a situation where the security and privacy of the terminal device's services are low; correspondingly, the situation where the second control plane no longer provides services to the terminal device may include a situation where the security and privacy of the terminal device's services are high. In other words, "the situation where the second control plane provides services to the terminal device" can be replaced by "the situation where the security and privacy of the terminal device's services are low," and "the situation where the second control plane no longer provides services to the terminal device" can be replaced by "the situation where the security and privacy of the terminal device's services are high."

[0169] For another example, the situation where the second control plane provides services to the terminal device may include: the situation where the second network is not congested; correspondingly, the situation where the second control plane no longer provides services to the terminal device may include: the situation where the second network is congested. In other words, "the situation where the second control plane provides services to the terminal device" can be replaced by "the situation where the second network is not congested", and "the situation where the second control plane no longer provides services to the terminal device" can be replaced by "the situation where the second network is congested."

[0170] For another example, the situation where the second control plane provides services to a terminal device may include: a situation where the first network is congested; correspondingly, the situation where the second control plane no longer provides services to the terminal device may include: a situation where the first network is not congested. In other words, "a situation where the second control plane provides services to the terminal device" can be replaced by "a situation where the first network is congested," and "a situation where the second control plane no longer provides services to the terminal device" can be replaced by "a situation where the first network is not congested."

[0171] It is understood that the above-mentioned situations are exemplary and the present application is not limited thereto. For example, any variation of the above-mentioned situations is applicable to the present application.

[0172] It can also be understood that the above “the second control plane device no longer provides services for the terminal device” does not limit “the second control plane device never provides services for the terminal device”, that is, it means that in some cases, the second control plane device temporarily stops providing services for the terminal device.

[0173] In the following text, for ease of understanding, the communication interface is mainly used as an example for illustrative explanation. It can be understood that the "situation where the communication interface connection is normal" mentioned below can be replaced by "the situation where the second control plane provides services for the terminal device", and the "situation where the communication interface connection fails" can be replaced by "the situation where the second control plane no longer provides services for the terminal device".

[0174] Optionally, the first network is a non-public network (also known as an enterprise private network or a local network), and the second network is a public network. Therefore, if a failure occurs in the communication interface between the public and non-public networks, the first control plane device in the non-public network provides control plane functions for the terminal device, thereby ensuring that the enterprise's business continues to operate normally and meeting the robustness requirements of the non-public network.

[0175] For example, the first network is the local network of the PNI-NPN, and the second network is the central network of the PNI-NPN (such as a PLMN). The first network can be deployed and operated by the second network. For example, the second network deploys the UPF to the first network, and the control plane network element (i.e., the second control plane device) is in the second network. The second control plane device may include, for example, a mobility management network element (referred to as a second mobility management network element for distinction) and a session management network element (referred to as a second session management network element for distinction). As an example, the second mobility management network element is an AMF. As an example, the second session management network element is an SMF.

[0176] Optionally, the communication interface includes: an N2 interface and / or an N4 interface.

[0177] For example, the UPF deployed in the first network and the SMF in the second network are interconnected through the N4 interface; for another example, the RAN (such as gNB) deployed in the first network and the AMF in the second network are interconnected through the N2 interface.

[0178] The communication interface connection failure between the first network and the second network may include, for example, a communication interface disconnection, such as N2 interface disconnection and / or N4 interface disconnection; or may also include a failure of the second network, without limitation.

[0179] It should be understood that the communication interface may include wires for coupling a wired connection or terminals and / or pins for coupling a wireless transceiver for a wireless connection. In some embodiments, the communication interface may include a transmitter, a receiver, a transceiver, and / or an antenna. The communication interface may be configured to use any available protocol (e.g., a 3GPP standard) for communication between devices. This will not be discussed further below.

[0180] The first control plane device 410, or referred to as a lightweight control plane (Light-CP, L-CP) function, can provide control plane functions for the terminal device. The control plane function can be part or all of the functions of the second control plane device, such as mobility management functions and session management functions. The first control plane device 410 provides control plane functions for the terminal device, for example, it can include that the first control plane device 410 performs part of the functions of the control plane to control the terminal device. Among them, the partial functions of the control plane refer to part of the functions in the control plane function. In addition, the first control plane device 410 provides control plane functions for the terminal device, and can also include transmitting control plane signaling of the terminal device between the first control plane device 410 and the first communication device 420.

[0181] Optionally, the first control plane device 410 includes a mobility management network element (referred to as a first mobility management network element for distinction) and a session management network element (referred to as a first session management network element for distinction). As an example, the first mobility management network element is an AMF. As an example, the first session management network element is an SMF. For distinction, this application refers to the AMF and SMF deployed in the first network as L-AMF and L-SMF, respectively.

[0182] Optionally, the first communication device 420 includes a RAN and a UPF.

[0183] It should be understood that the present application does not limit the number of first control plane devices 410 and the number of first communication devices 420. For example, the first control plane device 410 may include one or more devices (or one or more network elements, or one or more network slices, etc.). For another example, the first communication device 420 may include one or more devices (or one or more network elements, or one or more network slices, etc.).

[0184] Optionally, when the communication interface connection between the first network and the second network is normal, the first control plane device 410 is further configured to obtain an associated identifier (ID) of the terminal device. The associated identifier of the terminal device can be used to identify the terminal device, or in other words, can be used to identify the terminal device when the communication interface connection between the first network and the second network fails. For simplicity, the associated identifier of the terminal device is referred to as the UE ID hereinafter. Therefore, when the communication interface connection between the first network and the second network fails, the first control plane device 410 can perform signaling interaction on the communication interface for the terminal device based on the UE ID.

[0185] For example, the first control plane device 410 identifies which terminal device the signaling from the first communication device 420 belongs to based on the UE ID, and the first control plane device 410 can instruct the first communication device 420 to manage (or control) the corresponding terminal device based on the UE ID.

[0186] For example, when the first control plane device 410 includes multiple devices, such as the first control plane device 410 includes L-AMF and L-SMF, L-AMF and L-SMF may perform signaling interaction, so L-AMF and L-SMF can identify the same terminal device through the UE ID.

[0187] Optionally, the first control plane device 410 is configured to obtain the UE ID from the second control plane device. As an example, the context information of the terminal device is associated with the UE ID (or a corresponding relationship). Therefore, when the communication interface connection between the first network and the second network fails, the first control plane device can be configured to obtain the context information of the corresponding terminal device using the UE ID.

[0188] The form of association between the context information of the terminal device and the UE ID is not limited. One possible form is: the context information of the terminal device includes the UE ID; another possible form is: the context information of the terminal device is associated with the UE ID. It should be understood that this application does not limit the specific form of association. As long as the UE ID associated with the context information of the terminal device can be obtained based on the context information of the terminal device; or, based on the UE ID, the context information of the terminal device associated with the UE ID can be obtained, it is applicable to this application.

[0189] Among them, the specific manner in which the first control plane device 410 obtains the context information of the terminal device is not limited. For example, the first control plane device 410 is used to obtain the context information of the terminal device from the second control plane device, and the context information of the terminal device is associated with the UE ID. For another example, when the communication interface between the first network and the second network is connected normally, the first control plane device 410 is used to receive a first message (such as a context establishment request message, such as a session establishment request message) from the second control plane device, and establish the context information of the terminal device according to the first message, and save the context information of the terminal device, and the context information of the terminal device is associated with the UE ID.

[0190] Regarding the first control plane device 410 obtaining the UE ID and performing signaling interaction on the communication interface for the terminal device based on the UE ID, the following is combined with Figures 7 to 10 Detailed description.

[0191] Optionally, the UE ID is any one of the following: a user permanent identifier (such as a subscription permanent identifier (SUPI)), a globally unique temporary identifier (GUTI), a dedicated identifier, an N3 tunnel identifier (N3 tunnel ID) (or a UPF N3 tunnel ID).

[0192] The dedicated identifier may be an identifier used in the event of a communication interface connection failure. The specific form of the dedicated identifier is not limited. For example, the dedicated identifier may be represented by a number; or, for example, by a letter (e.g., an English letter).

[0193] It will be understood that this application mainly uses the UE ID as any of the above-mentioned items for illustrative purposes. For example, this application is not limited thereto, and any ID that can identify the UE is applicable to this application. For another example, the UE ID may include multiple items, such as the UE ID may include a SUPI and a dedicated identifier, etc., without limitation to this.

[0194] Optionally, the first communication device 420 includes a source access network device (such as a source RAN), and the communication system 400 also includes a target access network device. In the event of a failure in the communication interface connection between the first network and the second network, the first control plane device 410 is also used to switch the terminal device from the source access network device to the target access network device. Therefore, in a network switching scenario, that is, in a scenario where the terminal device switches from the source access network device to the target access network device, the first control plane device 410 can replace the second control plane device to control the process of switching the terminal device from the source access network device to the target access network device. Among them, switching can mean that the terminal device switches from the source access network device to the target access network device, and "switching" in the description can be replaced by "moving", "cell reselection" or "cell selection". Later combined Figures 7 to 10 Detailed description.

[0195] Optionally, when the communication interface connection failure between the first network and the second network is restored, the first control plane device 410 is further configured to trigger a path switching process for the terminal device so that the terminal device is connected to the second control plane device. Figure 11 Detailed description.

[0196] Assume that the first network is PNI-NPN and the second network is the central network PLMN of PNI-NPN. Figure 5 Schematic diagram of the network architecture provided according to the embodiment of the present application is shown. Figure 5As shown, the communication system deployed in the PNI-NPN includes: a first control plane device L-CP, a first communication device UPF, and a RAN. The L-CP may include an L-AMF and an L-SMF. The following describes two scenarios.

[0197] In case 1, the N2 and N4 interfaces are not faulty.

[0198] When the N2 interface and the N4 interface are not faulty, the L-CP can serve as a proxy node between the devices in the PNI-NPN and the devices in the PLMN, and transmit signaling between the devices in the PNI-NPN and the devices in the PLMN.

[0199] like Figure 5 As shown in the figure, for the N2 interface, the L-CP can be considered as an AMF for the RAN, and the L-CP can be considered as a RAN for the AMF. For example, when the RAN sends information to the AMF, it may include: the RAN first sends the information to the L-CP, and then the L-CP forwards the information to the AMF; when the AMF sends information to the RAN, it may include: the AMF first sends the information to the L-CP, and then the L-CP forwards the information to the RAN.

[0200] like Figure 5 As shown in the figure, for the N4 interface, the L-CP can be considered as an SMF for the UPF, and the L-CP can be considered as a UPF for the SMF. For example, when the UPF sends information to the SMF, it may include: the UPF first sends the information to the L-CP, and then the L-CP forwards the information to the SMF; when the SMF sends information to the UPF, it may include: the SMF first sends the information to the L-CP, and then the L-CP forwards the information to the UPF.

[0201] For example, when the N2 interface and the N4 interface are not faulty, the L-CP may also obtain the UE ID used on the N2 connection and the UE ID used on the N4 connection. For example, when the N2 connection is normal, the L-AMF in the L-CP obtains and stores UE context information, including the UE ID used on the N2 connection. For another example, when the N4 connection is normal, the L-SMF in the L-CP obtains and stores UE context information, including the UE ID used on the N4 connection.

[0202] Case 2: The N2 interface and / or the N4 interface fails.

[0203] If the N2 or N4 interface fails, the L-CP performs some control plane functions to control the terminal device, ensuring that enterprise services continue normally and meeting the robustness requirements of the PNI-NPN. These control plane functions include, for example, the L-AMF and / or L-SMF functions. For details on the L-AMF and L-SMF functions, refer to the AMF and SMF functions described above and are not detailed here.

[0204] As an example, when an N2 interface or an N4 interface fails, the L-CP may perform signaling interaction on the N2 interface or the N4 interface for the UE. For example, the L-CP performs signaling interaction on the N2 interface or the N4 interface for the UE based on previously stored UE context information.

[0205] pass Figure 5 In the provided network architecture, when a communication interface (such as the N2 interface and / or the N4 interface) between the PLMN and the PNI-NPN fails, the L-CP in the PNI-NPN performs some functions of the control plane to control the terminal device, thereby ensuring that the enterprise business continues to operate normally and meeting the robustness requirements of the PNI-NPN network.

[0206] Combined with the above Figure 4 and Figure 5 The network architecture provided by the embodiment of this application is introduced. Figure 4 and Figure 5 The network architecture in Figures 6 to 11 The communication method provided in the embodiments of the present application is introduced.

[0207] Figure 6 600 is a schematic diagram of a communication method 600 provided in an embodiment of the present application. The method 600 can be used as follows: Figure 4 or Figure 5 The method 600 may include the following steps.

[0208] 601. When the second control plane device provides services for the terminal device, the first control plane device forwards the control plane signaling of the terminal device transmitted between the first communication device and the second control plane device, and the second control plane device is used to provide control plane functions for the terminal device.

[0209] The second control plane device is a device deployed in the second network. For the first control plane device, the second control plane device, and the first communication device, please refer to the previous description and will not be repeated here.

[0210] 602. When the second control plane device no longer provides services for the terminal device, the first control plane device transmits control plane signaling of the terminal device to the first communication device, and the first control plane device provides control plane functions for the terminal device.

[0211] As an example, when the second control plane device no longer provides services for the terminal device, the control plane signaling of the terminal device transmitted between the first control plane device and the first communication device may include: signaling on the N2 interface (such as signaling between RAN and AMF) and / or signaling on the N4 interface (such as signaling between SMF and UPF).

[0212] Based on the above solution, when the second control plane device provides services to the terminal device, the first control plane device can act as a proxy device (or proxy node) between the first communication device and the second control plane device, forwarding signaling between the first communication device and the second control plane device. When the second control plane device no longer provides services to the terminal device, the first control plane device can perform control plane functions to control the terminal device. This enables the network to provide services to users, thereby ensuring the stability of user services as much as possible and achieving continuity of user services. Taking the communication interface as an example, when the communication interface between the first network and the second network is connected normally, the first control plane device can act as a proxy device (or proxy node) between the first communication device and the second control plane device, forwarding signaling between the first communication device and the second control plane device. When the communication interface between the first network and the second network fails, the first control plane device can perform control plane functions to control the terminal device to prevent the terminal device from being unable to connect to the first network after the communication interface between the first network and the second network fails. Therefore, not only will the normal communication between the first communication device and the second control plane device not be affected when the communication interface connection between the first network and the second network is normal, but also when the communication interface connection between the first network and the second network fails, the business of the terminal device can continue to operate normally.

[0213] Among them, the situation where the second control plane device provides services for the terminal device, and the situation where the second control plane device no longer provides services for the terminal device, which means that in some cases, the second control plane device provides services for the terminal device, and in some cases, the second control plane device no longer provides services for the terminal device. For details, please refer to the previous description, which will not be repeated here. In the following, for ease of understanding, the communication interface is mainly used as an example for illustrative explanation. It can be understood that the "situation where the communication interface connection is normal" mentioned below can be replaced with "the situation where the second control plane provides services for the terminal device", and the "situation where the communication interface connection fails" can be replaced with "the situation where the second control plane no longer provides services for the terminal device".

[0214] Optionally, when the communication interface between the first network and the second network is connected normally, the first control plane device obtains the UE ID. Therefore, when the communication interface between the first network and the second network fails, the first control plane device can perform signaling interaction on the communication interface for the terminal device based on the UE ID. For details, please refer to the previous description and will not be repeated here.

[0215] There are many ways for the first control plane device to obtain the UE ID, which are not limited.

[0216] In a first possible manner, the first control plane device receives the UE ID from the second control plane device. For example, the second control plane device sends a context establishment request message to the first control plane device, and the context establishment request message carries the UE ID. For another example, during the PDU session establishment process, the second control plane device sends a session establishment request message to the first control plane device, and the session establishment request message carries the UE ID. Regarding the manner in which the second control plane device determines the UE ID, the following text will be combined with Figures 7 to 10 Provide explanation.

[0217] In a second possible approach, the first control plane device receives the UE ID from the first communications device. For example, if the UE ID is a UPF N3 tunnel ID and the first communications device includes a UPF, and if the UPF assigns a UPF N3 tunnel ID, the UPF sends the UPF N3 tunnel ID to the first control plane device. For example, during a PDU session establishment process, after the UPF receives a session establishment request message from a second control plane device, the UPF sends a session establishment response message to the second control plane device via the first control plane device. The session establishment response message carries the UPF N3 tunnel ID.

[0218] The third possible way is that the UE ID is exchanged between the first control plane devices. For example, the first control plane device includes AMF and SMF. After AMF obtains the UE ID, it sends the UE ID to SMF. Correspondingly, SMF receives the UE ID from AMF. Furthermore, when the communication interface connection fails, SMF can identify the session context of the terminal device based on the UE ID. Wherein, AMF obtains the UE ID, which may include: AMF identifies the context of the terminal device based on the control plane port identifier (such as the tunnel port identifier), and obtains the UE ID based on the context of the terminal device. Wherein, the control plane port identifier is the port identifier of the control plane interface between the AMF and the access network device. Wherein, the context information of the terminal device includes the UE ID, or the context information of the terminal device is associated with the UE ID, and then AMF can obtain the corresponding UE ID based on the context of the terminal device. It should be understood that the above possible ways are only exemplary descriptions, and the present application is not limited to this.

[0219] Optionally, the method 600 further includes: the first control plane device switches the terminal device from the source access network device to the target access network device. Therefore, the first control plane device can replace the second control plane device to switch the terminal device from the source access network device to the target access network device. Figure 6 The method provided is about the process of the first control plane device switching the terminal device from the source access network device to the target access network device, and then combined with Figures 7 to 10 Detailed description.

[0220] Optionally, when the communication interface connection failure between the first network and the second network is restored, the first control plane device triggers a path switching process for the terminal device so that the terminal device is connected to the second control plane device. Figure 11 Detailed description.

[0221] For ease of understanding, take the communication interface as an example. Figures 7 to 11 Introducing possible processes applicable to embodiments of the present application. As mentioned above, UE ID can have different forms, Figures 7 to 10 This section mainly introduces the possible processes by which the first control plane device provides control plane functions for the terminal device when the UE ID is in different forms; Figure 11 This section mainly introduces the possible process of the first control plane device triggering the path switching process for the terminal device after the communication interface connection failure between the first network and the second network is restored (that is, the second control plane device resumes providing services to the terminal device). Figure 7The method 700 shown can be used in a scenario where the UEID is SUPI, that is, when the communication interface connection between the first network and the second network fails (that is, an example in which the second control plane device no longer provides services for the terminal device), the first control plane device can perform signaling interaction on the communication interface for the terminal device based on SUPI. Figure 8 The method 800 shown can be used in a scenario where the UE ID is a GUTI or S-TMSI, that is, when the communication interface connection between the first network and the second network fails (that is, an example in which the second control plane device no longer provides services for the terminal device), the first control plane device can perform signaling interaction on the communication interface for the terminal device based on the GUTI or S-TMSI. Figure 9 The method 900 shown can be used in a scenario where the UE ID is a dedicated identifier, that is, when the communication interface connection between the first network and the second network fails (that is, an example in which the second control plane device no longer provides services for the terminal device), the first control plane device can perform signaling interaction on the communication interface for the terminal device based on the dedicated identifier. Figure 10 The method 1000 shown can be used in a scenario where the UE ID is a UPF N3 tunnel ID, that is, when the communication interface connection between the first network and the second network fails (that is, an example in which the second control plane device no longer provides services for the terminal device), the first control plane device can perform signaling interaction on the communication interface for the terminal device based on the UPF N3 tunnel ID. Figure 11 The method 1100 shown can be used to trigger a path switching process for a terminal device after a communication interface connection failure between a first network and a second network is restored, so that the terminal device can reconnect to the second control plane device.

[0222] In the following example, it is assumed that the first control plane device L-CP includes L-SMF and L-AMF; the second control plane device deployed in the second network (such as PLMN) includes SMF and AMF, the SMF is called PLMN-SMF, and the AMF is called PLMN-AMF; the first communication device includes UPF, S-RAN, and T-RAN; the terminal device is UE, the access network device of the UE before switching is S-RAN, and the access network device of the UE after switching is T-RAN.

[0223] Figure 7 A schematic flow chart of a communication method 700 provided in an embodiment of the present application is shown. The method 700 may include the following steps.

[0224] 701, establish a communication connection between the L-CP and other devices.

[0225] Among them, other devices include devices deployed in the first network, such as S-RAN and UPF, and other devices also include devices deployed in the second network, such as PLMN-SMF and PLMN-AMF.

[0226] As an example, step 701 may include the following:

[0227] 1) A communication connection is established between the L-AMF and the S-RAN, and a communication connection is established between the L-AMF and the AMF.

[0228] The L-AMF establishes a node-level (or device-level) N2 signaling connection with the S-RAN in the role of AMF, including establishing an Internet Protocol Address Security (IPsec) security channel. Similarly, the L-AMF establishes a node-level (or device-level) N2 signaling connection with the AMF in the role of RAN, including establishing an IPsec security channel.

[0229] 2) A communication connection is established between L-SMF and UPF, and a communication connection is established between L-SMF and SMF.

[0230] The L-SMF establishes a node-level (or device-level) N4 signaling connection with the UPF in the role of SMF, including establishing an IPsec secure channel. Similarly, the L-SMF establishes a node-level (or device-level) N4 signaling connection with the SMF in the role of UPF, including establishing an IPsec secure channel.

[0231] It can be understood that "the L-AMF establishes a node-level N2 signaling connection with the S-RAN in the role of an AMF" means that the L-AMF, as an AMF, establishes a node-level N2 signaling connection with the S-RAN. Other details are similar and are not repeated here.

[0232] 702. UE requests to access the network.

[0233] The UE requests to access the network and sends a registration request or a service request (SR) to the network.

[0234] Taking the UE sending a registration request to the network as an example, a possible process includes: the UE sends a registration request to the S-RAN, and after the S-RAN receives the registration request from the UE, it sends an initial UE message to the L-AMF to trigger the L-AMF to initiate the establishment of an N2 signaling connection corresponding to the UE (for simplicity, it can be referred to as the establishment of a per UE N2 signaling connection); L-AMF acts as a proxy node, forwarding the initial UE message to the PLMN-AMF to trigger the PLMN-AMF to initiate the establishment of a per UE N2 signaling connection, and forwarding (or transparently transmitting) the registration request to the PLMN-AMF.

[0235] The establishment of a per UE N2 signaling connection initiated by the L-AMF may include, for example, the establishment of a per UE N2 signaling connection between the L-AMF and the S-RAN, and the establishment of a per UE N2 signaling connection between the L-AMF and the PLMN-AMF. The per UE N2 signaling connection between the L-AMF and the S-RAN and the per UE N2 signaling connection between the L-AMF and the PLMN-AMF may be two different independent N2 connections.

[0236] The PLMN-AMF initiates the establishment of a per UE N2 signaling connection, which may include, for example, the establishment of a per UE N2 signaling connection between the PLMN-AMF and the S-RAN, and the establishment of a per UE N2 signaling connection between the PLMN-AMF and the L-AMF. In one possible process, the PLMN-AMF sends an initial context setup request message to the L-AMF, after which the L-AMF forwards the initial context setup request message to the S-RAN. In response, the S-RAN returns an initial context setup response message to the L-AMF, after which the L-AMF forwards the initial context setup response message to the PLMN-AMF.

[0237] 703: PLMN-AMF and UE perform security authentication and key negotiation.

[0238] If the PLMN-AMF does not store the UE's security context information, or if security authentication and key agreement are not performed between the UE and the network, the PLMN-AMF and the UE perform a security authentication and key agreement process.

[0239] Among them, the specific process of performing security authentication and key agreement between the PLMN-AMF and the UE can refer to the description in the prior art and is not limited.

[0240] 704. PLMN-AMF determines to use SUPI as UE ID.

[0241] UE ID, used for identifying the UE and managing (or controlling) the UE based on the UE ID in the event of a connection failure in the communication interface (N2 interface and / or N4 interface) between the first network and the second network.

[0242] One possible way is that after successfully securely authenticating the UE, the PLMN-AMF can determine whether the slice corresponding to the UE's network slice selection assistance information (NSSAI) is an enterprise slice or whether there is a robustness claim, or whether there is a robustness claim in the first network (i.e., private network). If the PLMN-AMF determines that the slice corresponding to the UE's NSSAI is an enterprise slice or there is a robustness claim, or there is a robustness claim in the first network, then the PLMN-AMF learns that the normal operation of the service under fault conditions needs to be considered for the UE, and the PLMN-AMF determines to use the SUPI as the UE ID.

[0243] The PLMN-AMF may send the SUPI to the L-AMF via N2 signaling. For example, the Initial Context Setup Request message sent by the PLMN-AMF to the L-AMF may carry the SUPI.

[0244] 705. PLMN-AMF returns registration acceptance information or service acceptance information to the UE.

[0245] Taking the PLMN-AMF returning the registration acceptance information to the UE as an example, one possible way is that the initial context establishment request message sent by the PLMN-AMF to the L-AMF carries the registration acceptance information, the initial context establishment request message sent by the L-AMF to the S-RAN carries the registration acceptance information, and the S-RAN sends the registration acceptance information to the UE through the RRC message.

[0246] Optionally, the initial context establishment request message sent by the PLMN-AMF to the L-AMF, and the initial context establishment request message sent by the L-AMF to the S-RAN, include information for establishing a UE context. The L-AMF and the S-RAN may each create a RAN UE context based on the initial context establishment request message.

[0247] Among them, the information used to establish the UE context may include, but is not limited to, one or more of the following: UE aggregate maximum bit rate, UE security capability, security keys, UE radio capability, allowed network slice selection assistance information (allowed NSSAI), mobility restriction list, frequency selection priority (RFSP), and RRC-inactive assistance information.

[0248] 706. The L-AMF saves the created RAN UE context.

[0249] The RAN UE context is associated with (or corresponds to) a SUPI. The RAN UE context and the SUPI are associated, in one possible form: the RAN UE context includes the SUPI; in another possible form: the RAN UE context is associated with the SUPI. It should be understood that this application does not limit the specific form of association; as long as the SUPI associated with the RAN UE context can be obtained based on the RAN UE context, or the RAN UE context associated with the SUPI can be obtained based on the SUPI, the present application is applicable.

[0250] 707. The UE initiates a protocol data unit (PDU) session establishment.

[0251] After the UE accesses the network, a PDU session is established. For example, the UE sends a PDU session establishment request message to the L-AMF, which then forwards the message to the PLMN-AMF. Through this established PDU session, the UE can access the application server in the DN network. It can be understood that once a PDU session is established, a data transmission channel is established between the UE and the DN.

[0252] 708. PLMN-AMF sends a PDU session establishment request message to PLMN-SMF.

[0253] After the PLMN-AMF receives the PDU session establishment request message from the UE, the PLMN-AMF can select an appropriate PLMN-SMF for the UE and send a PDU session establishment request message to the PLMN-SMF.

[0254] 709. PLMN-SMF sends an N4 session establishment request message to UPF.

[0255] After the PLMN-SMF receives the UE's PDU Session Establishment Request message from the PLMN-AMF, the PLMN-SMF sends an N4 Session Establishment Request message to the UPF. The N4 Session Establishment Request message carries the SUPI. For example, the PLMN-SMF sends the N4 Session Establishment Request message to the L-SMF, and the L-SMF forwards the N4 Session Establishment Request message to the UPF.

[0256] 710. The UPF sends an N4 session establishment response message to the PLMN-SMF.

[0257] After the UPF receives the N4 Session Setup Request message from the PLMN-SMF, the UPF sends an N4 Session Setup Response message to the PLMN-SMF. For example, the UPF sends an N4 Session Setup Response message to the L-SMF, and the L-SMF forwards the N4 Session Setup Response message to the PLMN-SMF.

[0258] After receiving the N4 session establishment response message, the L-SMF saves the UE's session management (SM) context information. The UE's SM context information is associated with (or corresponds to) the SUPI, for example, the UE's SM context information includes the SUPI; or the UE's SM context information is associated with the SUPI.

[0259] After receiving the N4 Session Establishment Response message, the PLMN-SMF continues to execute the PDU session establishment process, which may include: sending a PDU Session Resource Establishment Request message to the S-RAN and sending a PDU Session Establishment Accept message to the UE. The PDU Session Resource Establishment Request message can be used to establish the N3 interface data transmission channel and air interface data radio bearer (DRB(s)) for the PDU session.

[0260] The above steps 701 to 710 are possible processes before the N2 interface and / or N4 interface fails. The following describes possible processes after the N2 interface and / or N4 interface fails, in conjunction with steps 711 to 718.

[0261] 711. When the N2 interface and / or the N4 interface fails, the L-CP provides a control plane function for the UE.

[0262] For example, when the N2 interface fails, the L-AMF performs the proxy N2 interface function and replaces the PLMN-AMF to control the UE.

[0263] For example, when the N4 interface fails, the L-SMF performs the proxy N4 interface function and replaces the PLMN-SMF to control the UE.

[0264] For example, when both the N2 interface and the N4 interface fail, the L-AMF performs the proxy N2 interface function, and the L-SMF performs the proxy N4 interface function. The L-AMF and L-SMF replace the PLMN-AMF and PLMN-SMF respectively to control the UE.

[0265] The following mainly takes the network handover scenario as an example, that is, the UE switches from S-RAN to T-RAN, to introduce the process of L-AMF and L-SMF replacing PLMN-AMF and PLMN-SMF respectively to control the UE.

[0266] 712. T-RAN sends a path switch request message to L-AMF.

[0267] In one possible way, the T-RAN initiates a path switch for the UE, that is, the T-RAN sends a path switch request message to the L-AMF.

[0268] It should be understood that, before step 712, method 700 may further include handover preparation between the S-RAN, the T-RAN, and the UE, which is not limited in this application.

[0269] 713. The L-AMF identifies the RANUE context and obtains the SUPI associated with the RANUE context.

[0270] After the L-AMF receives the Path Switch Request message from the T-RAN, it can identify the RAN UE context based on the AMF NG-AP Tunnel Endpoint Identifier (TEID). Based on the RAN UE context, the L-AMF can obtain the SUPI associated with the RAN UE context (or the SUPI corresponding to the RAN UE context).

[0271] In one possible scenario, the RAN UE context includes a SUPI in step 706. In this case, obtaining the SUPI associated with the RAN UE context can be understood as obtaining the SUPI included in the RAN UE context.

[0272] In another possible scenario, the RAN UE context is associated with a SUPI in step 706. In this case, obtaining the SUPI associated with the RAN UE context can be understood as obtaining the SUPI associated with the RAN UE context.

[0273] 714. L-AMF sends a PDU session management context update request (Nsmf_PDUSession_UpdateSMContext Request) message to L-SMF.

[0274] The PDU session management context update request message carries SUPI, and the PDU session management context update request message can be used to establish a signaling association between the L-AMF and the L-SMF for the UE.

[0275] It should be understood that the PDU session management context update request message is only one possible method, and the name of the message is not limited. Any message that can achieve the function of the message is applicable to the embodiments of the present application.

[0276] 715. The L-SMF obtains the SM context associated with the SUPI according to the SUPI.

[0277] The L-SMF obtains the SM context associated with the SUPI based on the SUPI, so as to send the N3ANtunnelinfo allocated by the T-RAN to the UE to the UPF.

[0278] In one possible scenario, in step 710, the UE's SM context information includes a SUPI. In this case, obtaining the SM context information associated with the SUPI can be understood as obtaining the SM context information including the SUPI.

[0279] In another possible scenario, in step 710, the UE's SM context information is associated with the SUPI. In this case, obtaining the SM context information associated with the SUPI can be understood as obtaining the SM context information associated with the SUPI.

[0280] 716, the L-SMF and the UPF execute the N4 session modification process.

[0281] For example, the L-SMF uses the per UE N4 signaling connection previously established with the UPF to send an N4 session modification request message to the UPF. The N4 session modification request message carries the N3 AN tunnel info allocated by the T-RAN to the UE. Correspondingly, the UPF can send an N4 session modification response message to the L-SMF.

[0282] 717. L-SMF sends a PDU session management context update response (Nsmf_PDUSession_UpdateSMContext Response) message to L-AMF.

[0283] The PDU session management context update response message is a response to the PDU session management context update request message in step 714 .

[0284] It should be understood that the PDU session management context update response message is only one possible method, and the name of the message is not limited. Any message that can achieve the function of the message is applicable to the embodiments of the present application.

[0285] 718. The L-AMF returns a path update response message to the T-RAN.

[0286] Taking into account the scenario where the communication interface fails, the L-AMF does not need to generate new security parameters (such as the intermediate key NH) for the UE, and the path update response message does not need to carry the security parameter NH. The L-AMF does not need to generate new security parameters for the UE. Therefore, not only can the L-AMF provide control plane functions for the terminal device when the communication interface connection between the first network and the second network fails, but it can also reduce the requirements for the L-AMF and make little changes to the existing protocol.

[0287] Based on the above scheme, when the communication interface connection between the first network and the second network is normal, L-SMF and L-AMF can act as proxy devices (or proxy nodes) between the first communication device and the second control plane device to forward signaling between the first communication device and the second control plane device. When the communication interface connection between the first network and the second network fails, L-SMF and L-AMF can control the terminal device based on SUPI instead of PLMN-SMF and PLMN-AMF to avoid the terminal device being unable to connect to the first network after the communication interface between the first network and the second network fails. Thus, not only does it not affect the normal communication between the first communication device and the second control plane device when the communication interface connection between the first network and the second network is normal, but also when the communication interface connection between the first network and the second network fails, the business of the terminal device can continue normally.

[0288] Figure 8 A schematic flow chart of a communication method 800 provided in an embodiment of the present application is shown. The method 800 may include the following steps.

[0289] 801: A communication connection is established between the L-CP and other devices.

[0290] 802. UE requests to access the network.

[0291] 803: PLMN-AMF and UE perform security authentication and key negotiation.

[0292] Among them, steps 801-803 are similar to steps 701-703 and are not repeated here.

[0293] 804. PLMN-AMF determines to use the GUTI as the UE ID.

[0294] Alternatively, the PLMN-AMF determines to use the serving-temporary mobile subscriber identity (S-TMSI) as the UE ID. Method 800 is mainly described using the GUTI as an example. It is understood that the "GUTI" in method 800 can also be replaced by "S-TMSI".

[0295] In one possible way, after successfully securely authenticating the UE, the PLMN-AMF can determine whether the slice corresponding to the UE's NSSAI is an enterprise slice or whether there is a robustness claim, or whether the first network (i.e., private network) has a robustness claim. If the PLMN-AMF determines that the slice corresponding to the UE's NSSAI is an enterprise slice or there is a robustness claim, or there is a robustness claim in the first network, then the PLMN-AMF learns that the normal operation of the service under fault conditions needs to be considered for the UE, and the PLMN-AMF determines to use the GUTI as the UE ID.

[0296] The PLMN-AMF may send the GUTI to the L-AMF via N2 signaling. For example, the Initial Context Setup Request message sent by the PLMN-AMF to the L-AMF may carry the GUTI.

[0297] 805. PLMN-AMF returns registration acceptance information or service acceptance information to the UE.

[0298] Step 805 is similar to step 705 and will not be described again here.

[0299] 806. The L-AMF saves the created RAN UE context.

[0300] The RAN UE context has an association relationship (or a corresponding relationship) with the GUTI. The RAN UE context and the GUTI have an association relationship, one possible form of which is: the RAN UE context includes the GUTI; another possible form is: the RAN UE context is associated with the GUTI. It should be understood that this application does not limit the specific form of association. As long as the GUTI associated with the RAN UE context can be obtained based on the RAN UE context; or, the RAN UE context associated with the GUTI can be obtained based on the GUTI, both are applicable to this application.

[0301] 807. The UE initiates PDU session establishment.

[0302] Step 807 is similar to step 707 and will not be repeated here.

[0303] 808. PLMN-AMF sends a PDU session establishment request message to PLMN-SMF.

[0304] After the PLMN-AMF receives the PDU session establishment request message from the UE, the PLMN-AMF can select an appropriate PLMN-SMF for the UE and send a PDU session establishment request message to the PLMN-SMF.

[0305] If the PLMN-AMF determines that the UE's NSSAI or data network name (DNN) has a robustness claim, or if the first network (i.e., private network) has a robustness claim, the PLMN-AMF may send the GUTI to the selected PLMN-SMF. For example, the GUTI may be carried in the PDU Session Establishment Request message.

[0306] 809. PLMN-SMF sends an N4 session establishment request message to UPF.

[0307] After the PLMN-SMF receives the UE's PDU Session Establishment Request message from the PLMN-AMF, the PLMN-SMF sends an N4 Session Establishment Request message to the UPF. The N4 Session Establishment Request message carries the GUTI. For example, the PLMN-SMF sends the N4 Session Establishment Request message to the L-SMF, and the L-SMF forwards the N4 Session Establishment Request message to the UPF.

[0308] 810. UPF sends an N4 session establishment response message to PLMN-SMF.

[0309] After the UPF receives the N4 Session Setup Request message from the PLMN-SMF, the UPF sends an N4 Session Setup Response message to the PLMN-SMF. For example, the UPF sends an N4 Session Setup Response message to the L-SMF, and the L-SMF forwards the N4 Session Setup Response message to the PLMN-SMF.

[0310] After receiving the N4 session establishment response message, the L-SMF saves the UE's SM context information. The UE's SM context information has an association relationship (or a corresponding relationship) with the GUTI, such as the UE's SM context information includes the GUTI; or the UE's SM context information is associated with the GUTI.

[0311] After receiving the N4 session establishment response message, the PLMN-SMF continues to execute the PDU session establishment process. Specifically, please refer to the description in step 710, which will not be repeated here.

[0312] The above steps 801 to 810 are possible processes before the N2 interface and / or N4 interface fails. The following describes possible processes after the N2 interface and / or N4 interface fails, in conjunction with steps 811 to 818.

[0313] 811, when the N2 interface and / or the N4 interface fails, the L-CP provides control plane functions for the UE.

[0314] 812. T-RAN sends a path switch request message to L-AMF.

[0315] Among them, steps 811-812 are similar to steps 711-712 and will not be repeated here.

[0316] 813. The L-AMF identifies the RAN UE context and obtains the GUTI associated with the RAN UE context.

[0317] After the L-AMF receives the Path Switch Request message from the T-RAN, it can identify the RAN UE context based on the AMF NG-AP TEID. Based on the RAN UE context, the L-AMF can obtain the GUTI associated with the RAN UE context (or the GUTI corresponding to the RAN UE context).

[0318] In one possible scenario, the RAN UE context includes a GUTI in step 806. In this case, obtaining the GUTI associated with the RAN UE context can be understood as obtaining the GUTI included in the RAN UE context.

[0319] In another possible case, the RAN UE context and the GUTI have an association relationship (or a corresponding relationship) in step 806. In this case, obtaining the GUTI associated with the RAN UE context can be understood as obtaining the GUTI associated with the RAN UE context.

[0320] 814. L-AMF sends a PDU session management context update request message to L-SMF.

[0321] The PDU session management context update request message carries the GUTI, and the PDU session management context update request message can be used to establish a signaling association between the L-AMF and the L-SMF for the UE.

[0322] 815. The L-SMF obtains the SM context associated with the GUTI according to the GUTI.

[0323] The L-SMF obtains the SM context associated with the GUTI based on the GUTI, so as to send the N3 ANtunnel info allocated by the T-RAN to the UE to the UPF.

[0324] In one possible scenario, in step 810, the UE's SM context information includes a GUTI. In this case, obtaining the SM context information associated with the GUTI can be understood as obtaining the SM context information including the GUTI.

[0325] In another possible case, in step 810, the UE's SM context information has an association relationship (or a corresponding relationship) with the GUTI. In this case, obtaining the SM context information associated with the GUTI can be understood as obtaining the SM context information associated with the GUTI.

[0326] 816, the N4 session modification process is executed between the L-SMF and the UPF.

[0327] 817. L-SMF sends a PDU session management context update response message to L-AMF.

[0328] 818. The L-AMF returns a path update response message to the T-RAN.

[0329] Among them, steps 816-818 are similar to steps 716-718 and are not repeated here.

[0330] Based on the above scheme, when the communication interface connection between the first network and the second network is normal, L-SMF and L-AMF can act as proxy devices (or proxy nodes) between the first communication device and the second control plane device to forward signaling between the first communication device and the second control plane device. When the communication interface connection between the first network and the second network fails, L-SMF and L-AMF can replace PLMN-SMF and PLMN-AMF to control the terminal device based on GUTI or S-TMSI to avoid the terminal device being unable to connect to the first network after the communication interface between the first network and the second network fails. Thus, not only does it not affect the normal communication between the first communication device and the second control plane device when the communication interface connection between the first network and the second network is normal, but also when the communication interface connection between the first network and the second network fails, the business of the terminal device can continue normally.

[0331] Figure 9 A schematic flow chart of a communication method 900 provided in an embodiment of the present application is shown. The method 900 may include the following steps.

[0332] 901: Establish a communication connection between the L-CP and other devices.

[0333] 902. UE requests to access the network.

[0334] 903: PLMN-AMF and UE perform security authentication and key negotiation.

[0335] Among them, steps 901-903 are similar to steps 701-703 and are not repeated here.

[0336] 904. PLMN-AMF configures a dedicated identifier for the UE.

[0337] That is, the UE ID is a dedicated identifier. This dedicated identifier is used to identify the UE and manage (or control) the UE based on the dedicated identifier in the event of a connection failure in the communication interface (N2 interface and / or N4 interface) between the first network and the second network. The specific form of the dedicated identifier is not limited. For example, the dedicated identifier can be represented by an ID, such as different UEs corresponding to different IDs; for example, the dedicated identifier can be represented by letters (such as English letters).

[0338] In one possible way, after successfully securely authenticating the UE, the PLMN-AMF can determine whether the slice corresponding to the UE's NSSAI is an enterprise slice or whether there is a robustness claim, or whether the first network (i.e., private network) has a robustness claim. If the PLMN-AMF determines that the slice corresponding to the UE's NSSAI is an enterprise slice or there is a robustness claim, or there is a robustness claim in the first network, then the PLMN-AMF learns that the normal operation of the service under fault conditions needs to be considered for the UE, and the PLMN-AMF can configure (or generate) a dedicated identifier for the UE.

[0339] The PLMN-AMF may send the dedicated identifier to the L-AMF via N2 signaling. For example, the initial context establishment request message sent by the PLMN-AMF to the L-AMF includes the dedicated identifier.

[0340] It should be understood that method 900 is mainly illustrated by taking the example of the PLMN-AMF configuring a dedicated identifier for the UE, and the present application is not limited thereto. For example, it may also be a dedicated identifier pre-defined by the protocol, or it may also be a dedicated identifier pre-configured by other network devices, or it may also be a dedicated identifier pre-stored by the PLMN-AMF.

[0341] 905. The PLMN-AMF returns registration acceptance information or service acceptance information to the UE.

[0342] Step 905 is similar to step 705 and will not be described again here.

[0343] 906. The L-AMF saves the RAN UE context.

[0344] The RAN UE context has an association relationship (or a corresponding relationship) with the dedicated identifier. The RAN UE context has an association relationship with the dedicated identifier. One possible form of the association relationship is: the RAN UE context includes the dedicated identifier; another possible form is: the RAN UE context is associated with the dedicated identifier. It should be understood that this application does not limit the specific form of the association. As long as the dedicated identifier associated with the RAN UE context can be obtained based on the RAN UE context; or the RAN UE context associated with the dedicated identifier can be obtained based on the dedicated identifier, both are applicable to this application.

[0345] 907. The UE initiates PDU session establishment.

[0346] Step 907 is similar to step 707 and will not be repeated here.

[0347] 908. The PLMN-AMF sends a PDU session establishment request message to the PLMN-SMF.

[0348] After the PLMN-AMF receives the PDU session establishment request message from the UE, the PLMN-AMF can select an appropriate PLMN-SMF for the UE and send a PDU session establishment request message to the PLMN-SMF.

[0349] If the PLMN-AMF determines that the UE's NSSAI or DNN has a robustness claim, or that the first network (i.e., private network) has a robustness claim, the PLMN-AMF may send a dedicated identifier to the selected PLMN-SMF. For example, the dedicated identifier may be carried in the PDU Session Establishment Request message.

[0350] 909. PLMN-SMF sends an N4 session establishment request message to UPF.

[0351] After the PLMN-SMF receives the UE's PDU Session Establishment Request message from the PLMN-AMF, the PLMN-SMF sends an N4 Session Establishment Request message to the UPF. The N4 Session Establishment Request message carries a dedicated identifier. For example, the PLMN-SMF sends an N4 Session Establishment Request message to the L-SMF, and the L-SMF forwards the N4 Session Establishment Request message to the UPF.

[0352] 910. UPF sends an N4 session establishment response message to PLMN-SMF.

[0353] After the UPF receives the N4 Session Setup Request message from the PLMN-SMF, the UPF sends an N4 Session Setup Response message to the PLMN-SMF. For example, the UPF sends an N4 Session Setup Response message to the L-SMF, and the L-SMF forwards the N4 Session Setup Response message to the PLMN-SMF.

[0354] After receiving the N4 session establishment response message, the L-SMF saves the UE's SM context information. The UE's SM context information has an association relationship (or a corresponding relationship) with the dedicated identifier, such as the UE's SM context information includes the dedicated identifier; or the UE's SM context information is associated with the dedicated identifier.

[0355] After receiving the N4 session establishment response message, the PLMN-SMF continues to execute the PDU session establishment process. Specifically, please refer to the description in step 710, which will not be repeated here.

[0356] The above steps 901 to 910 are possible processes before the N2 interface and / or N4 interface fails. The following describes possible processes after the N2 interface and / or N4 interface fails, in conjunction with steps 911 to 918.

[0357] 911, when the N2 interface and / or the N4 interface fails, the L-CP provides control plane functions for the UE.

[0358] 912. T-RAN sends a path switch request message to L-AMF.

[0359] Among them, steps 911-912 are similar to steps 711-712 and are not repeated here.

[0360] 913. The L-AMF identifies the RAN UE context and obtains the dedicated identifier associated with the RAN UE context.

[0361] After the L-AMF receives the Path Switch Request message from the T-RAN, it can identify the RAN UE context based on the AMF NG-AP TEID. Based on the RAN UE context, the L-AMF can obtain the dedicated identifier associated with the RAN UE context (or the dedicated identifier corresponding to the RAN UE context).

[0362] In one possible scenario, the RAN UE context includes a dedicated identifier in step 906. In this case, obtaining the dedicated identifier associated with the RAN UE context can be understood as obtaining the dedicated identifier included in the RAN UE context.

[0363] In another possible case, the RAN UE context has an association relationship (or a corresponding relationship) with the dedicated identity in step 906. In this case, obtaining the dedicated identity associated with the RAN UE context can be understood as obtaining the dedicated identity associated with the RAN UE context.

[0364] 914. L-AMF sends a PDU session management context update request message to L-SMF.

[0365] The PDU session management context update request message carries a dedicated identifier, and the PDU session management context update request message can be used to establish a signaling association between the L-AMF and L-SMF for the UE.

[0366] 915. The L-SMF obtains the SM context associated with the dedicated identifier according to the dedicated identifier.

[0367] The L-SMF obtains the SM context associated with the dedicated identifier based on the dedicated identifier, so as to send the N3 AN tunnel info allocated by the T-RAN to the UE to the UPF.

[0368] In one possible scenario, the UE's SM context information includes a dedicated identifier in step 810. In this case, acquiring the SM context information associated with the dedicated identifier can be understood as acquiring the SM context information including the dedicated identifier.

[0369] In another possible case, the UE's SM context information has an association relationship (or a corresponding relationship) with the dedicated identity in step 810. In this case, obtaining the SM context information associated with the dedicated identity can be understood as obtaining the SM context information associated with the dedicated identity.

[0370] 916, execute the N4 session modification process between L-SMF and UPF.

[0371] 917. L-SMF sends a PDU session management context update response message to L-AMF.

[0372] 918. The L-AMF returns a path update response message to the T-RAN.

[0373] Among them, steps 916-918 are similar to steps 716-718 and are not repeated here.

[0374] Based on the above scheme, when the communication interface connection between the first network and the second network is normal, L-SMF and L-AMF can act as proxy devices (or called proxy nodes) between the first communication device and the second control plane device to forward the signaling between the first communication device and the second control plane device. When the communication interface connection between the first network and the second network fails, L-SMF and L-AMF can control the terminal device based on a dedicated identifier instead of PLMN-SMF and PLMN-AMF to avoid the terminal device being unable to connect to the first network after the communication interface between the first network and the second network fails. Thus, not only does it not affect the normal communication between the first communication device and the second control plane device when the communication interface connection between the first network and the second network is normal, but also when the communication interface connection between the first network and the second network fails, the business of the terminal device can continue normally.

[0375] Figure 10 A schematic flow chart of a communication method 1000 provided in an embodiment of the present application is shown. The method 1000 may include the following steps.

[0376] 1001: A communication connection is established between the L-CP and other devices.

[0377] 1002. UE requests to access the network.

[0378] 1003: PLMN-AMF and UE perform security authentication and key negotiation.

[0379] Among them, steps 1001-1003 are similar to steps 701-703 and are not repeated here.

[0380] 1004. PLMN-AMF returns registration acceptance information or service acceptance information to the UE.

[0381] Step 1004 is similar to step 705 and will not be described again here.

[0382] 1005. The L-AMF saves the RAN UE context.

[0383] 1006. The UE initiates PDU session establishment.

[0384] Step 1006 is similar to step 707 and will not be repeated here.

[0385] 1007. PLMN-AMF sends a PDU session establishment request message to PLMN-SMF.

[0386] After the PLMN-AMF receives the PDU session establishment request message from the UE, the PLMN-AMF can select an appropriate PLMN-SMF for the UE and send a PDU session establishment request message to the PLMN-SMF.

[0387] 1008. PLMN-SMF sends an N4 session establishment request message to UPF.

[0388] After the PLMN-SMF receives the UE's PDU session establishment request message from the PLMN-AMF, the PLMN-SMF sends an N4 session establishment request message to the UPF. For example, the PLMN-SMF sends an N4 session establishment request message to the L-SMF, and the L-SMF forwards the N4 session establishment request message to the UPF.

[0389] 1009. UPF sends an N4 session establishment response message to PLMN-SMF.

[0390] After the UPF receives the N4 Session Setup Request message from the PLMN-SMF, the UPF sends an N4 Session Setup Response message to the PLMN-SMF. For example, the UPF sends an N4 Session Setup Response message to the L-SMF, and the L-SMF forwards the N4 Session Setup Response message to the PLMN-SMF.

[0391] In one possible scenario, if the PLMN-SMF assigns a UPF N3 tunnel ID, the N4 session establishment request message in step 1008 carries the UPF N3 tunnel ID. For example, the PLMN-SMF sends the N4 session establishment request message to the L-SMF, which then forwards the message to the UPF. Upon receiving the N4 session establishment request message, the L-SMF saves the UE's SM context information. The UE's SM context information is associated (or corresponds) with the UPF N3 tunnel ID, for example, the UE's SM context information includes the UPF N3 tunnel ID, or the UE's SM context information is associated with the UPF N3 tunnel ID.

[0392] In another possible scenario, if the UPF assigns a UPF N3 tunnel ID, then in step 1009, the N4 session establishment response message sent by the UPF to the PLMN-SMF carries the UPF N3 tunnel ID. For example, the UPF sends the N4 session establishment response message to the L-SMF, and the L-SMF forwards the N4 session establishment response message to the PLMN-SMF. Upon receiving the N4 session establishment response message, the L-SMF saves the UE's SM context information. The UE's SM context information is associated (or corresponds) with the UPF N3 tunnel ID, for example, the UE's SM context information includes the UPF N3 tunnel ID, or the UE's SM context information is associated with the UPF N3 tunnel ID.

[0393] In addition, after receiving the N4 session establishment response message, the PLMN-SMF continues to execute the PDU session establishment process, which may include: sending a PDU session resource establishment request from the PLMN-SMF to the S-RAN, and sending a PDU session establishment accept message to the UE. The PDU session resource establishment request includes the UPF N3 tunnel ID. The L-AMF obtains the UPF N3 tunnel ID from the PDU session resource establishment request message sent by the PLMN-SMF to the S-RAN and associates it with the NG-AP AMF ID for storage.

[0394] The above steps 1001 to 1009 are possible processes before the N2 interface and / or N4 interface fails. The following describes possible processes after the N2 interface and / or N4 interface fails, in conjunction with steps 1010 to 1017.

[0395] 1010. When the N2 interface and / or the N4 interface fails, the L-CP provides a control plane function for the UE.

[0396] 1011. T-RAN sends a path switch request message to L-AMF.

[0397] Among them, steps 1010-1011 are similar to steps 711-712 and will not be repeated here.

[0398] 1012. The L-AMF identifies the RAN UE context and obtains the UPF N3 tunnelID associated with the RAN UE context.

[0399] After the L-AMF receives the Path Switch Request message from the T-RAN, it can identify the RAN UE context based on the AMF NG-AP TEID. Based on the RAN UE context, the L-AMF can obtain the UPF N3tunnel ID associated with the RAN UE context.

[0400] 1013. L-AMF sends a PDU session management context update request message to L-SMF.

[0401] The PDU session management context update request message carries a dedicated identifier, and the PDU session management context update request message can be used to establish a signaling association between the L-AMF and L-SMF for the UE.

[0402] 1014. L-SMF obtains the SM context associated with the UPF N3 tunnel ID based on the UPF N3 tunnel ID.

[0403] The L-SMF obtains the SM context associated with the UPF N3 tunnel ID based on the UPF N3 tunnel ID, so as to send the N3 AN tunnel info allocated by the T-RAN to the UE to the UPF.

[0404] In one possible scenario, in step 1009, the UE's SM context information includes the UPF N3 tunnel ID. In this case, obtaining the SM context information associated with the UPF N3 tunnel ID can be understood as obtaining the SM context information including the UPF N3 tunnel ID.

[0405] In another possible scenario, in step 1009, the UE's SM context information has an association relationship (or a corresponding relationship) with the UPF N3 tunnel ID. In this case, obtaining the SM context information associated with the UPF N3 tunnel ID can be understood as obtaining the SM context information associated with the UPF N3 tunnel ID.

[0406] 1015, execute the N4 session modification process between L-SMF and UPF.

[0407] 1016. L-SMF sends a PDU session management context update response message to L-AMF.

[0408] 1017. L-AMF returns a path update response message to T-RAN.

[0409] Among them, steps 1015-1017 are similar to steps 716-718 and are not repeated here.

[0410] Based on the above solution, when the communication interface connection between the first network and the second network is normal, the L-SMF and L-AMF can act as proxy devices (or proxy nodes) between the first communication device and the second control plane device, forwarding signaling between the first communication device and the second control plane device. When the communication interface connection between the first network and the second network fails, the L-SMF and L-AMF can control the terminal device based on the UPF N3 tunnel ID, replacing the PLMN-SMF and PLMN-AMF, to prevent the terminal device from being unable to connect to the first network after a failure in the communication interface between the first network and the second network. This not only does it not affect normal communication between the first communication device and the second control plane device when the communication interface connection between the first network and the second network is normal, but it also allows the terminal device's services to continue normally when the communication interface connection between the first network and the second network fails.

[0411] Combined with the above Figures 7 to 10 This mainly introduces the process of L-SMF and L-AMF replacing PLMN-SMF and PLMN-AMF to control the terminal device when the communication interface connection between the first network and the second network fails. Figure 11 This section describes the process after a communication interface connection failure is restored.

[0412] Figure 11 A schematic flow chart of a communication method 1100 provided in an embodiment of the present application is shown. The method 1100 may include the following steps.

[0413] 1101, L-AMF detects that the communication interface connection failure is restored.

[0414] If the L-AMF detects that the connection failure of the communication interface (N2 interface and / or N4 interface) is restored, the L-AMF triggers a path process for the UE so that the UE reconnects to the PLMN-AMF and / or PLMN-SMF.

[0415] 1102. L-AMF sends a path switch request message to PLMN-AMF.

[0416] 1103. PLMN-AMF sends a PDU session context update request message to PLMN-SMF.

[0417] 1104. The N4 session modification process is executed between the PLMN-SMF and the L-SMF.

[0418] In one possible scenario, if the L-SMF learns that the N4 session modification process is the first N4 process after fault recovery, the L-SMF does not send the N3 RAN tunnel ID to the UPF, that is, the L-SMF does not perform the N4 session modification process with the UPF.

[0419] In another possible situation, if the L-SMF learns that the N4 session modification process is the first N4 process after fault recovery, the L-SMF and UPF execute the N4 session modification process, and during the execution of the N4 session modification process by the L-SMF and UPF, the N3RAN tunnel ID is not sent to the UPF.

[0420] In another possible situation, if the L-SMF learns that the N4 session modification process is the first N4 process after fault recovery, the L-SMF and UPF execute the N4 session modification process, and during the execution of the N4 session modification process by the L-SMF and UPF, the N3RAN tunnel ID is sent to the UPF, and the N3RAN tunnel ID is the previous N3RAN tunnel ID.

[0421] In either of the above cases, the UPF will still use the original N3 RAN tunnel ID.

[0422] 1105. PLMN-AMF returns a path switching response message to L-AMF.

[0423] If the PLMN-AMF identifies that the RAN after the fault recovery belongs to a device in a non-public network and the path switch is the first path switch after the fault recovery, no new security parameter NH is generated for the UE, and the path switch response message may not carry the security parameter NH. Considering that the RAN after the fault recovery belongs to a device in a non-public network and the path switch is the first path switch after the fault recovery, the PLMN-AMF does not need to generate new security parameters for the UE, which not only saves resources but also minimizes changes to existing protocols.

[0424] 1106. The L-CP stops controlling the UE.

[0425] That is to say, L-AMF and L-SMF no longer replace PLMN-AMF and PLMN-SMF to perform control plane functions to control terminal devices.

[0426] 1107. The L-CP acts as a proxy node and forwards signaling transmitted between the RAN / UPF and the PLMN-AMF and PLMN-SMF.

[0427] After the UE reconnects to the PLMN-AMF and PLMN-SMF, the L-AMF acts as a proxy node to forward (or transfer) the signaling transmitted between the RAN and the PLMN-AMF, and the L-SMF acts as a proxy node to forward (or transfer) the signaling transmitted between the UPF and the PLMN-SMF.

[0428] It is understood that method 1100 and methods 700-1000 can be used in combination. For example, before step 1101, Angfa 1100 can also include the steps in methods 700-1000.

[0429] Based on the above solution, when the communication interface connection failure between the first network and the second network is restored, the L-AMF and L-SMF can trigger a path switching process for the terminal device so that the terminal device can reconnect to the PLMN-AMF and PLMN-SMF. The L-AMF and L-SMF can act as proxy nodes to forward signaling transmitted between the RAN / UPF and the PLMN-AMF and PLMN-SMF. This does not affect the normal communication between the first communication device and the second control plane device when the communication interface connection between the first network and the second network is normal, ensuring the normal transmission of terminal device services.

[0430] It can be understood that the embodiments of this application Figures 7 to 11 The examples are only for the convenience of those skilled in the art to understand the embodiments of the present application, and are not intended to limit the embodiments of the present application to the specific scenarios illustrated. Figures 7 to 11 Obviously, various equivalent modifications or changes can be made to the examples, and such modifications or changes also fall within the scope of the embodiments of the present application. Figures 7 to 11 The "situation where the communication interface connection is normal" can be replaced by "situation where the second control plane provides services for the terminal device", and the "situation where the communication interface connection fails" can be replaced by "situation where the second control plane no longer provides services for the terminal device".

[0431] It can also be understood that some optional features in the various embodiments of the present application may not depend on other features in certain scenarios, and may also be combined with other features in certain scenarios, without limitation.

[0432] It can also be understood that the solutions in the various embodiments of the present application can be reasonably combined and used, and the explanations or descriptions of the various terms appearing in the embodiments can be referenced or explained with each other in the various embodiments, without limitation to this.

[0433] It can also be understood that the sizes of the various numerical serial numbers in the embodiments of the present application do not mean the order of execution, but are only distinguished for the convenience of description and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0434] It can also be understood that some message names are involved in the various embodiments of the present application, such as a path switching request message or a PDU session management context update request message, etc. It should be understood that their naming does not limit the scope of protection of the embodiments of the present application.

[0435] It is also understood that in some of the above embodiments, the communication interface is mainly used as an example for illustrative description, and the present application is not limited thereto. The phrase "a situation in which the communication interface connection is normal" can be replaced with "a situation in which the second control plane provides services to the terminal device," and the phrase "a situation in which the communication interface connection fails" can be replaced with "a situation in which the second control plane no longer provides services to the terminal device."

[0436] It can also be understood that in some of the above embodiments, the mobile management network element is AMF and the session management network element is SMF as an example for illustrative explanation. The present application is not limited to this. Any network element that can implement AMF, or any network element that can implement SMF is applicable to the present application.

[0437] It can also be understood that in the above-mentioned method embodiments, the methods and operations implemented by a device or network element (such as a first control plane device, and also a second control plane device) can also be implemented by components that can be implemented by the device or network element (such as a chip or circuit).

[0438] Corresponding to the methods provided in the above method embodiments, embodiments of the present application also provide corresponding apparatuses, which include modules for executing the corresponding methods in the above method embodiments. The modules may be software, hardware, or a combination of software and hardware. It is understood that the technical features described in the above method embodiments are also applicable to the following apparatus embodiments.

[0439] Figure 12 1 is a schematic block diagram of a communication device provided in an embodiment of the present application. The device 1200 includes a transceiver unit 1210, which can be used to implement corresponding communication functions. The transceiver unit 1210 can also be called a communication interface or a communication unit.

[0440] Optionally, the device 1200 may further include a processing unit 1220 , which may be configured to perform data processing.

[0441] Optionally, the device 1200 also includes a storage unit, which can be used to store instructions and / or data, and the processing unit 1220 can read the instructions and / or data in the storage unit so that the device implements the actions of the network device (such as a control plane device, such as a mobility management network element, such as a session management network element) in the aforementioned method embodiments.

[0442] The device 1200 can be used to execute the actions performed by the network device (such as the first control plane device, and the second control plane device) in the above method embodiments. In this case, the device 1200 can be a network device or a component of a network device. The transceiver unit 1210 is used to execute the transceiver-related operations on the network device side in the above method embodiments, and the processing unit 1220 is used to execute the processing-related operations on the network device side in the above method embodiments.

[0443] As a design, the apparatus 1200 is used to execute the actions performed by the first control plane device in each of the above method embodiments.

[0444] In one possible implementation, the apparatus 1200 is deployed in a first network. When the second control plane device provides services for the terminal device, the transceiver unit 1210 is used to forward control plane signaling of the terminal device transmitted between a first communication device deployed in the first network and a second control plane device deployed in the second network, and the second control plane device is used to provide control plane functions for the terminal device, wherein the second control plane device is a device deployed in the second network; when the second control plane device no longer provides services for the terminal device, the transceiver unit 1210 is used to transmit control plane signaling with the first communication device, and the apparatus 1200 is used to provide control plane functions for the terminal device.

[0445] In some possible implementations, when the second control plane device provides services for the terminal device, the transceiver unit 1210 is further configured to obtain an association identifier of the terminal device.

[0446] For example, the transceiver unit 1210 is configured to obtain an association identifier of a terminal device, including: the transceiver unit 1210 is configured to receive an association identifier of the terminal device from a second control plane device.

[0447] For example, when the second control plane device provides services for the terminal device, the transceiver unit 1210 is also used to receive a first message from the second control plane device; the processing unit 1220 is used to save the context information of the terminal device based on the first message, wherein the context information of the terminal device is associated with the association identifier of the terminal device.

[0448] In some possible implementations, when the second control plane device no longer provides services for the terminal device, the transceiver unit 1210 is further configured to obtain context information of the terminal device through an association identifier of the terminal device.

[0449] Optionally, the associated identifier of the terminal device is any one of the following: a user permanent identifier, a globally unique temporary identifier, a dedicated identifier, and an N3 tunnel identifier.

[0450] In some possible embodiments, the first communication device includes a source access network device, and the first network also includes a target access network device. When the second control plane device no longer provides services for the terminal device, the processing unit 1220 is used to switch the terminal device from the source access network device to the target access network device.

[0451] For example, the first communication device also includes a user plane functional network element, and the transceiver unit 1210 is used to receive a switching request message from the target access network device, the switching request message including the N3 tunnel information allocated by the target access network device to the terminal device; the transceiver unit 1210 is also used to obtain the association identifier of the terminal device; the transceiver unit 1210 is used to send the N3 tunnel information to the user plane functional network element based on the association identifier of the terminal device.

[0452] In some possible implementations, when the second control plane device no longer provides services for the terminal device, if the second control plane device resumes providing services for the terminal device, the processing unit 1220 is further configured to trigger a path switching process for the terminal device so that the terminal device is connected to the second control plane device.

[0453] Optionally, the first control plane device includes: a first mobility management network element and / or a first session management network element.

[0454] Optionally, the first network is a local network in which a public network is integrated with a non-public network, and the second network is a central network in which a public network is integrated with a non-public network.

[0455] Optionally, the communication interface includes an N2 interface and / or an N4 interface.

[0456] The apparatus 1200 may implement the steps or processes executed by the first control plane device in the method embodiment according to the embodiment of the present application. The apparatus 1200 may include a method for executing Figure 6 The unit of the method performed by the first control plane device in the embodiment shown, or including Figures 7 to 11 A unit of the method performed by the L-AMF and L-SMF in any of the illustrated embodiments.

[0457] As another design, the device 1200 is used to execute the actions performed by the first mobility management network element (such as L-AMF) in each of the above method embodiments.

[0458] In one possible implementation, the transceiver unit 1210 is used to obtain an association identifier of a terminal device, and the association identifier of the terminal device is used to identify the terminal device when a second control plane device deployed in a second network no longer provides services for the terminal device; the transceiver unit 1210 is also used to send the association identifier of the terminal device to a first session management network element; wherein, the device 1200 and the first session management network element are deployed in the first network.

[0459] In some possible implementations, when the second control plane device provides services for the terminal device, the transceiver unit 1210 is further configured to receive an association identifier of the terminal device from a second mobility management network element deployed in the second network.

[0460] For example, when the second control plane device provides services for the terminal device, the transceiver unit 1210 is also used to receive a first message from the second mobile management network element; the processing unit 1220 is used to save the context information of the terminal device based on the first message, and the context information of the terminal device is associated with the association identifier of the terminal device.

[0461] In some possible embodiments, when the second control plane device no longer provides services for the terminal device, the processing unit 1220 is used to identify the context of the terminal device based on the control plane port identifier, wherein the control plane port identifier is the port identifier of the control plane interface between the first mobility management network element and the access network device; and obtain the association identifier of the terminal device based on the context of the terminal device.

[0462] In some possible implementations, when the second control plane device no longer provides services for the terminal device, if the second control plane device resumes providing services for the terminal device, the processing unit 1220 is configured to trigger a path switching process for the terminal device so that the terminal device establishes a communication connection with the second session management network element and / or the second mobility management network element, wherein the second session management network element and the second mobility management network element are deployed in the second network.

[0463] Optionally, the associated identifier of the terminal device is any one of the following: a user permanent identifier, a globally unique temporary identifier, a dedicated identifier, and an N3 tunnel identifier.

[0464] The device 1200 can implement the steps or processes performed by the first mobility management network element in the method embodiment according to the embodiment of the present application. Figures 7 to 11 A unit of the method performed by the L-AMF in any of the illustrated embodiments.

[0465] As another design, the device 1200 is used to execute the actions performed by the first session management network element (such as L-SMF) in each of the above method embodiments.

[0466] In one possible implementation, the transceiver unit 1210 is used to receive an association identifier of a terminal device from a first mobility management network element, where the association identifier of the terminal device is used to identify the terminal device when a second control plane device deployed in a second network no longer provides services for the terminal device; when the second control plane device no longer provides services for the terminal device, the processing unit 1220 is used to identify the session context associated with the association identifier of the terminal device based on the association identifier of the terminal device; wherein the device 1200 and the first mobility management network element are deployed in the first network.

[0467] In some possible implementations, when the second control plane device provides services for the terminal device, the transceiver unit 1210 is further configured to receive an association identifier of the terminal device from a second session management network element, where the second mobility management network element is deployed in the second network.

[0468] In some possible implementations, when the second control plane device provides services for the terminal device, the transceiver unit 1210 is further used to receive a first message from a second session management network element, where the second session management network element is deployed in the second network; and the processing unit 1220 is used to save context information of the terminal device based on the first message, where the context information of the terminal device is associated with an association identifier of the terminal device.

[0469] In some possible implementations, when the second control plane device no longer provides services for the terminal device, the transceiver unit 1210 is further used to obtain context information of the terminal device based on the association identifier of the terminal device, and send a session modification request message to the user plane functional network element.

[0470] Optionally, the associated identifier of the terminal device is any one of the following: a user permanent identifier, a globally unique temporary identifier, a dedicated identifier, and an N3 tunnel identifier.

[0471] The apparatus 1200 can implement the steps or processes performed by the first session management network element in the method embodiment according to the embodiment of the present application. Figures 7 to 11 A unit of the method performed by the L-SMF in any of the illustrated embodiments.

[0472] As another design, the device 1200 is used to execute the actions performed by the second mobility management network element (such as PLMN-AMF) in the above method embodiments.

[0473] One possible implementation method is that the processing unit 1220 is used for the second mobility management network element to determine the association identifier of the terminal device, and the association identifier of the terminal device is used to identify the terminal device when the second control plane device deployed in the second network no longer provides services for the terminal device; the transceiver unit 1210 is used to send the association identifier of the terminal device to the first mobility management network element; wherein the first mobility management network element is deployed in the first network, and the device 1200 is deployed in the second network.

[0474] For example, the processing unit 1220 is used to determine the association identifier of the terminal device, including: if the network slice supported by the terminal device and / or the first network has robustness requirements, then the processing unit 1220 is used to determine the association identifier of the terminal device.

[0475] In some possible implementations, the transceiver unit 1210 is further configured to send an association identifier of the terminal device to a second session management network element, where the second session management network element is deployed in the second network.

[0476] Optionally, the associated identifier of the terminal device is any one of the following: a user permanent identifier, a globally unique temporary identifier, or a dedicated identifier.

[0477] The device 1200 can implement the steps or processes performed by the second mobility management network element in the method embodiment according to the embodiment of the present application. Figures 7 to 11 A unit of the method performed by the PLMN-AMF in any of the embodiments shown.

[0478] As another design, the apparatus 1200 is configured to execute the actions executed by the second session management network element (eg, PLMN-SMF) in each of the above method embodiments.

[0479] In one possible implementation, the transceiver unit 1210 is used to obtain an association identifier of a terminal device, and the association identifier of the terminal device is used to identify the terminal device when a second control plane device deployed in a second network no longer provides services for the terminal device; the transceiver unit 1210 is also used to send the association identifier of the terminal device to a first session management network element; wherein the first session management network element is deployed in the first network, and the device 1200 is deployed in the second network.

[0480] In some possible implementations, if the network slice supported by the terminal device or the first network has robustness requirements, the transceiver unit 1210 is also used to send the association identifier of the terminal device to the user plane function network element, and the user plane function network element is deployed in the first network.

[0481] For example, the processing unit 1220 is configured to determine an association identifier of a terminal device; or the transceiver unit 1210 is configured to receive an association identifier of a terminal device from a second mobility management network element, where the second mobility management network element is deployed in the second network.

[0482] Optionally, the associated identifier of the terminal device is any one of the following: a user permanent identifier, a globally unique temporary identifier, or a dedicated identifier.

[0483] The device 1200 can implement the steps or processes performed by the second session management network element in the method embodiment according to the embodiment of the present application. Figures 7 to 11 A unit of the method performed by the PLMN-SMF in any one of the illustrated embodiments.

[0484] It should be understood that the specific process of each unit executing the above corresponding steps has been described in detail in the above method embodiments, and for the sake of brevity, it will not be repeated here.

[0485] It should also be understood that the device 1200 here is embodied in the form of a functional unit. The term "unit" here can refer to an application specific integrated circuit (ASIC), an electronic circuit, a processor (such as a shared processor, a dedicated processor or a group processor, etc.) and a memory for executing one or more software or firmware programs, a combined logic circuit and / or other suitable components that support the described functions. In an optional example, those skilled in the art will understand that the device 1200 can be specifically a network device (such as a first control plane device, such as a second control plane device) in the above-mentioned embodiments, and can be used to execute the various processes and / or steps corresponding to the network device (such as a first control plane device, such as a second control plane device) in the above-mentioned method embodiments. To avoid repetition, they will not be described here.

[0486] The apparatus 1200 of each of the above-mentioned solutions has the function of implementing the corresponding steps performed by the network device (such as the first control plane device, and the second control plane device) in the above-mentioned method. The functions can be implemented by hardware, or the corresponding software can be implemented by hardware. The hardware or software includes one or more modules corresponding to the above-mentioned functions; for example, the transceiver unit can be replaced by a transceiver (for example, the sending unit in the transceiver unit can be replaced by a transmitter, and the receiving unit in the transceiver unit can be replaced by a receiver), and other units, such as the processing unit, can be replaced by a processor to respectively perform the sending and receiving operations and related processing operations in each method embodiment.

[0487] In addition, the transceiver unit 1210 may also be a transceiver circuit (for example, may include a receiving circuit and a transmitting circuit), and the processing unit may be a processing circuit.

[0488] It should be pointed out that Figure 12 The device in the embodiment may be a network element or device as described in the preceding embodiments, or may be a chip or chip system, such as a system on chip (SoC). The transceiver unit may be an input / output circuit or a communication interface; the processing unit may be a processor, microprocessor, or integrated circuit integrated on the chip. This is not limited here.

[0489] like Figure 13 As shown, an embodiment of the present application provides another communication device 1300. The device 1300 includes a processor 1310, which is coupled to a memory 1320. The memory 1320 is used to store computer programs or instructions and / or data. The processor 1310 is used to execute the computer programs or instructions stored in the memory 1320, or read the data stored in the memory 1320, to perform the methods in the above method embodiments.

[0490] Optionally, there are one or more processors 1310 .

[0491] Optionally, there are one or more memories 1320 .

[0492] Optionally, the memory 1320 is integrated with the processor 1310 or provided separately.

[0493] Alternatively, as Figure 13 As shown, the device 1300 further includes a transceiver 1330, which is used to receive and / or send signals. For example, the processor 1310 is used to control the transceiver 1330 to receive and / or send signals.

[0494] As a solution, the apparatus 1300 is used to implement the operations performed by the network device (eg, the first control plane device, or the second control plane device) in the above method embodiments.

[0495] For example, the processor 1310 is configured to execute the computer program or instructions stored in the memory 1320 to implement the relevant operations of the first control plane device in each of the above method embodiments. Figure 4 or Figure 5 The first control plane device in the embodiment shown, or Figures 6 to 11 A method performed by a first control plane device in any one of the embodiments shown.

[0496] It should be understood that the processor mentioned in the embodiments of the present application may be a central processing unit (CPU), or may be other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field programmable gate arrays (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor may be a microprocessor or any conventional processor, etc.

[0497] It should also be understood that the memory mentioned in the embodiments of the present application may be a volatile memory and / or a non-volatile memory. Among them, the non-volatile memory may be a read-only memory (ROM), a programmable read-only memory (PROM), an erasable programmable read-only memory (EPROM), an electrically erasable programmable read-only memory (EEPROM), or a flash memory. The volatile memory may be a random access memory (RAM). For example, RAM can be used as an external cache. By way of example and not limitation, RAM includes the following forms: static random access memory (SRAM), dynamic random access memory (DRAM), synchronous dynamic random access memory (SDRAM), double data rate synchronous dynamic random access memory (DDR SDRAM), enhanced synchronous dynamic random access memory (ESDRAM), synchronous link dynamic random access memory (SLDRAM), and direct rambus RAM (DR RAM).

[0498] 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, discrete hardware component, the memory (storage module) can be integrated into the processor.

[0499] It should also be noted that the memory described herein is intended to comprise, but not be limited to, these and any other suitable types of memory.

[0500] like Figure 14 The embodiment of the present application provides a chip system 1400. The chip system 1400 (or also referred to as a processing system) includes a logic circuit 1410 and an input / output interface 1420.

[0501] Logic circuit 1410 may be a processing circuit within chip system 1400. Logic circuit 1410 may be coupled to a storage unit and invoke instructions within the storage unit, enabling chip system 1400 to implement the methods and functions of various embodiments of the present application. Input / output interface 1420 may be an input / output circuit within chip system 1400, outputting information processed by chip system 1400 or inputting data or signaling information to be processed into chip system 1400 for processing.

[0502] As a solution, the chip system 1400 is used to implement the operations performed by the network device (such as the first control plane device, and such as the second control plane device) in the above various method embodiments.

[0503] For example, the logic circuit 1410 is used to implement the processing-related operations performed by the first control plane device in the above method embodiment, such as Figures 6 to 11 The input / output interface 1420 is used to implement the sending and / or receiving related operations performed by the first control plane device in the above method embodiment, such as Figures 6 to 11 The first control plane device in any one of the embodiments shown in the drawings performs sending and / or receiving related operations.

[0504] An embodiment of the present application further provides a computer-readable storage medium storing computer instructions for implementing the methods executed by a network device (such as a first control plane device or a second control plane device) in the above-mentioned method embodiments.

[0505] For example, when the computer program is executed by a computer, the computer can implement the method performed by the first control plane device in each embodiment of the above method.

[0506] An embodiment of the present application further provides a computer program product comprising instructions, which, when executed by a computer, implement the methods performed by the network device (such as the first control plane device or the second control plane device) in the above-mentioned method embodiments.

[0507] The explanation of the relevant contents and beneficial effects of any of the above-mentioned devices can be referred to the corresponding method embodiments provided above, which will not be repeated here.

[0508] In the several embodiments provided in this application, it should be understood that the disclosed devices and methods can be implemented in other ways. For example, the device embodiments described above are only schematic. For example, the division of the units is only a logical function division. In actual implementation, there may be other division methods, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. In addition, the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0509] In the above embodiments, it can be implemented in whole or in part by software, hardware, firmware or any combination thereof. When implemented using software, it can be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, the process or function described in the embodiment of the present application is generated in whole or in part. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. For example, the computer can be a personal computer, a server, or a network device, etc. The computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another computer-readable storage medium. For example, the computer instructions can be transmitted from one website, computer, server or data center to another website, computer, server or data center by wired (e.g., coaxial cable, optical fiber, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) mode. The computer-readable storage medium can be any available medium that a computer can access or a data storage device such as a server or data center that includes one or more available media integrations. The available medium may be a magnetic medium (e.g., a floppy disk, a hard disk, a magnetic tape), an optical medium (e.g., a DVD), or a semiconductor medium (e.g., a solid state disk (SSD)). For example, the aforementioned available medium includes, but is not limited to, various media that can store program code, such as a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disk.

[0510] The above description is merely a specific embodiment of the present application, but the scope of protection of the present application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in this application should be included in the scope of protection of this application. Therefore, the scope of protection of this application should be based on the scope of protection of the claims.

Claims

1. A communication system, characterized in that: The communication system is deployed in a first network, and the first network and the second network communicate with each other via a communication interface; The communication system includes: a first control plane device and a first communication device, In the case where the second control plane device provides services for the terminal device, the first control plane device is used to forward the control plane signaling of the terminal device transmitted between the first communication device and the second control plane device, and the second control plane device is used to provide control plane functions for the terminal device. The second control plane device is a device deployed in the second network; In the case where the second control plane device no longer provides services for the terminal device, the first control plane device is used to transmit control plane signaling with the first communication device, and the first control plane device is also used to provide control plane functions for the terminal device.

2. The communication system according to claim 1, wherein: In a case where the second control plane device provides services for the terminal device, the first control plane device is further configured to obtain an association identifier of the terminal device.

3. The communication system according to claim 2, wherein: The first control plane device is further configured to obtain an association identifier of the terminal device, including: The first control plane device is configured to receive the association identifier of the terminal device from the second control plane device.

4. The communication system according to claim 3, wherein: In the case where the second control plane device provides services for the terminal device, The first control plane device is further configured to receive a first message from the second control plane device; The first control plane device is further used to save the context information of the terminal device according to the first message, wherein the context information of the terminal device is associated with the association identifier of the terminal device.

5. The communication system according to claim 4, wherein: When the second control plane device no longer provides services for the terminal device, The first control plane device is further configured to obtain context information of the terminal device through an association identifier of the terminal device.

6. The communication system according to claim 2, wherein: The associated identifier of the terminal device is any one of the following: User permanent identifier, globally unique temporary identifier, dedicated identifier, and N3 tunnel identifier.

7. The communication system according to any one of claims 1 to 6, characterized in that: The first communication device includes a source access network device, and the communication system further includes a target access network device. When the second control plane device no longer provides services for the terminal device, The first control plane device is further used to switch the terminal device from the source access network device to the target access network device.

8. The communication system according to claim 7, wherein: The first communication device further includes a user plane function network element and the first control plane device, and is further configured to switch the terminal device from the source access network device to the target access network device, including: The first control plane device is configured to receive a handover request message from the target access network device, where the handover request message includes N3 tunnel information allocated by the target access network device to the terminal device; The first control plane device is configured to obtain an association identifier of the terminal device; The first control plane device is used to send the N3 tunnel information to the user plane functional network element based on the association identifier of the terminal device.

9. The communication system according to any one of claims 1 to 6, characterized in that: In the case where the second control plane device no longer provides services for the terminal device, if the second control plane device provides services for the terminal device again, The first control plane device is further configured to trigger a path switching process for the terminal device so that the terminal device establishes a communication connection with the second control plane device.

10. The communication system according to any one of claims 1 to 6, characterized in that: The first control plane device includes: a first mobility management network element and / or a first session management network element.

11. The communication system according to any one of claims 1 to 6, characterized in that: The first network is a local network in which a public network is integrated with a non-public network, and the second network is a central network in which the public network is integrated with the non-public network.

12. The communication system according to any one of claims 1 to 6, characterized in that: The communication interface includes an N2 interface and / or an N4 interface.

13. A communication method, characterized in that: The method comprises: In a case where a second control plane device deployed in the second network provides services for the terminal device, the first control plane device deployed in the first network forwards control plane signaling of the terminal device transmitted between a first communication device deployed in the first network and the second control plane device, where the second control plane device is used to provide control plane functions for the terminal device; In a case where the second control plane device no longer provides services for the terminal device, control plane signaling is transmitted between the first control plane device and the first communication device, and the first control plane device provides control plane functions for the terminal device.

14. The method according to claim 13, characterized in that In a case where the second control plane device provides a service for the terminal device, the method further includes: The first control plane device obtains the association identifier of the terminal device.

15. The method according to claim 14, characterized in that The first control plane device obtaining the association identifier of the terminal device includes: The first control plane device receives the association identifier of the terminal device from the second control plane device.

16. The method according to claim 15, characterized in that In a case where the second control plane device provides a service for the terminal device, the method further includes: The first control plane device receives a first message from the second control plane device; The first control plane device saves the context information of the terminal device according to the first message, wherein the context information of the terminal device is associated with the association identifier of the terminal device.

17. The method according to claim 16, characterized in that In a case where the second control plane device no longer provides services for the terminal device, the method further includes: The first control plane device obtains the context information of the terminal device through the association identifier of the terminal device.

18. The method according to claim 14, characterized in that The associated identifier of the terminal device is any one of the following: User permanent identifier, globally unique temporary identifier, dedicated identifier, and N3 tunnel identifier.

19. The method according to any one of claims 13 to 18, characterized in that The first communication device includes a source access network device, and the first network also includes a target access network device. When the second control plane device no longer provides services for the terminal device, the method further includes: The first control plane device switches the terminal device from the source access network device to the target access network device.

20. The method according to claim 19, characterized in that The first communication device further includes a user plane function network element, and the first control plane device switches the terminal device from the source access network device to the target access network device, including: The first control plane device receives a handover request message from the target access network device, where the handover request message includes N3 tunnel information allocated by the target access network device to the terminal device; The first control plane device obtains an association identifier of the terminal device; The first control plane device sends the N3 tunnel information to the user plane functional network element based on the association identifier of the terminal device.

21. The method according to any one of claims 13 to 18, characterized in that The method further comprises: In the case where the second control plane device no longer provides services for the terminal device, if the second control plane device provides services for the terminal device again, the first control plane device triggers a path switching process for the terminal device so that the terminal device is connected to the second control plane device.

22. The method according to any one of claims 13 to 18, characterized in that The first control plane device includes: a first mobility management network element and / or a first session management network element.

23. The method according to any one of claims 13 to 18, characterized in that The first network is a local network in which a public network is integrated with a non-public network, and the second network is a central network in which the public network is integrated with the non-public network.

24. The method according to any one of claims 13 to 18, characterized in that The first network and the second network communicate with each other via a communication interface, and the communication interface includes an N2 interface and / or an N4 interface.

25. A communication method, characterized in that: The method comprises: The first mobility management network element obtains an association identifier of the terminal device, where the association identifier of the terminal device is used to identify the terminal device when a second control plane device deployed in the second network no longer provides services for the terminal device; The first mobility management network element sends the association identifier of the terminal device to the first session management network element; The first mobility management network element and the first session management network element are deployed in a first network; In which, when the second control plane device no longer provides services for the terminal device, the first mobility management network element and / or the first session management network element can be used to provide control plane functions for the terminal device; when the second control plane device provides services for the terminal device, the first mobility management network element and / or the first session management network element can be used to forward the control plane signaling of the terminal device transmitted between the first communication device and the second control plane device.

26. The method according to claim 25, characterized in that In a case where the second control plane device provides a service for the terminal device, the method further includes: The first mobility management network element receives the association identifier of the terminal device from a second mobility management network element, and the second mobility management network element is deployed in the second network.

27. The method according to claim 26, characterized in that In a case where the second control plane device provides a service for the terminal device, the method further includes: The first mobility management network element receives a first message from the second mobility management network element; The first mobility management network element saves the context information of the terminal device according to the first message, and the context information of the terminal device is associated with the association identifier of the terminal device.

28. The method according to any one of claims 25 to 27, characterized in that The first mobility management network element obtains the association identifier of the terminal device, including: In a case where the second control plane device no longer provides services for the terminal device, the first mobility management network element identifies the context of the terminal device according to the control plane port identifier, wherein the control plane port identifier is a port identifier of the control plane interface between the first mobility management network element and the access network device; The first mobility management network element obtains the association identifier of the terminal device according to the context of the terminal device.

29. The method according to any one of claims 25 to 27, characterized in that The method further comprises: In a case where the second control plane device no longer provides services for the terminal device, if the second control plane device resumes providing services for the terminal device, the first mobility management network element triggers a path switching process for the terminal device so that the terminal device establishes a communication connection with a second session management network element and / or a second mobility management network element, wherein the second session management network element and the second mobility management network element are deployed in the second network.

30. The method according to any one of claims 25 to 27, characterized in that The associated identifier of the terminal device is any one of the following: User permanent identifier, globally unique temporary identifier, dedicated identifier, and N3 tunnel identifier.

31. A communication method, characterized in that: The method comprises: The first session management network element receives an association identifier of the terminal device from the first mobility management network element, where the association identifier of the terminal device is used to identify the terminal device when a second control plane device deployed in the second network no longer provides services for the terminal device; When the second control plane device no longer provides services for the terminal device, the first session management network element identifies, according to the association identifier of the terminal device, a session context associated with the association identifier of the terminal device; The first session management network element and the first mobility management network element are deployed in a first network; In which, when the second control plane device no longer provides services for the terminal device, the first mobility management network element and / or the first session management network element can be used to provide control plane functions for the terminal device; when the second control plane device provides services for the terminal device, the first mobility management network element and / or the first session management network element can be used to forward the control plane signaling of the terminal device transmitted between the first communication device and the second control plane device.

32. The method according to claim 31, wherein In a case where the second control plane device provides a service for the terminal device, the method further includes: The first session management network element receives the association identifier of the terminal device from a second session management network element, where the second session management network element is deployed in the second network.

33. The method according to claim 31, characterized in that In a case where the second control plane device provides a service for the terminal device, the method further includes: The first session management network element receives a first message from a second session management network element, where the second session management network element is deployed in the second network; The first session management network element saves the context information of the terminal device according to the first message, and the context information of the terminal device is associated with the association identifier of the terminal device.

34. The method according to any one of claims 31 to 33, characterized in that When the second control plane device no longer provides services for the terminal device, the method further includes: The first session management network element obtains the context information of the terminal device according to the association identifier of the terminal device, and sends a session modification request message to the user plane function network element.

35. The method according to any one of claims 31 to 33, characterized in that The associated identifier of the terminal device is any one of the following: User permanent identifier, globally unique temporary identifier, dedicated identifier, and N3 tunnel identifier.

36. A communication method, characterized in that: The method comprises: The second mobility management network element determines an association identifier of the terminal device, where the association identifier of the terminal device is used to identify the terminal device when a second control plane device deployed in the second network no longer provides services for the terminal device; The second mobility management network element sends the association identifier of the terminal device to the first mobility management network element; The first mobility management network element is deployed in the first network, and the second mobility management network element is deployed in the second network; In which, when the second control plane device no longer provides services for the terminal device, the first mobility management network element can be used to provide control plane functions for the terminal device; when the second control plane device provides services for the terminal device, the first mobility management network element can be used to forward the control plane signaling of the terminal device transmitted between the first communication device and the second control plane device.

37. The method according to claim 36, wherein The second mobility management network element determines the association identifier of the terminal device, including: If the network slice supported by the terminal device and / or the first network has robustness requirements, the second mobility management network element determines the association identifier of the terminal device.

38. The method according to claim 36 or 37, characterized in that The method further comprises: The second mobility management network element sends the association identifier of the terminal device to a second session management network element, where the second session management network element is deployed in the second network.

39. The method according to claim 36 or 37, characterized in that The associated identifier of the terminal device is any one of the following: User permanent identification, globally unique temporary identification, and dedicated identification.

40. A communication method, characterized in that: The method comprises: The second session management network element obtains an association identifier of the terminal device, where the association identifier of the terminal device is used to identify the terminal device when a second control plane device deployed in the second network no longer provides services for the terminal device; The second session management network element sends the association identifier of the terminal device to the first session management network element; The first session management network element is deployed in the first network, and the second session management network element is deployed in the second network; In which, when the second control plane device no longer provides services for the terminal device, the first session management network element can be used to provide control plane functions for the terminal device; when the second control plane device provides services for the terminal device, the first session management network element can be used to forward the control plane signaling of the terminal device transmitted between the first communication device and the second control plane device.

41. The method according to claim 40, wherein The method further comprises: If the network slice supported by the terminal device or the first network has robustness requirements, the second session management network element sends the association identifier of the terminal device to the user plane function network element, and the user plane function network element is deployed in the first network.

42. The method according to claim 40 or 41, characterized in that The second session management network element obtains the association identifier of the terminal device, including: The second session management network element receives the association identifier of the terminal device from a second mobility management network element, where the second mobility management network element is deployed in the second network.

43. The method according to claim 40 or 41, characterized in that The associated identifier of the terminal device is any one of the following: User permanent identification, globally unique temporary identification, and dedicated identification.

44. A communication device, characterized in that include: A processor, configured to execute a computer program stored in a memory, so that the apparatus performs the method according to any one of claims 13 to 24, or so that the apparatus performs the method according to any one of claims 25 to 30, or so that the apparatus performs the method according to any one of claims 31 to 35, or so that the apparatus performs the method according to any one of claims 36 to 39, or so that the apparatus performs the method according to any one of claims 40 to 43.

45. The device according to claim 44, characterized in that The apparatus further comprises the memory.

46. ​​A computer-readable storage medium, characterized in that The computer-readable storage medium stores a computer program, which, when executed on a computer, enables the computer to execute the method according to any one of claims 13 to 24, or the method according to any one of claims 25 to 30, or the method according to any one of claims 31 to 35, or the method according to any one of claims 36 to 39, or the method according to any one of claims 40 to 43.

47. A computer program product, characterized in that The computer program product comprises instructions for performing the method of any one of claims 13 to 24, or the computer program product comprises instructions for performing the method of any one of claims 25 to 30, or the computer program product comprises instructions for performing the method of any one of claims 31 to 35, or the computer program product comprises instructions for performing the method of any one of claims 36 to 39, or the computer program product comprises instructions for performing the method of any one of claims 40 to 43.

48. A communication system, characterized in that Include one or more of the following: a first control plane device, wherein the first control plane device is configured to perform the method according to any one of claims 13 to 24; A second mobility management network element, wherein the second mobility management network element is configured to execute the method according to any one of claims 36 to 39; or A second session management network element, wherein the second session management network element is configured to execute the method according to any one of claims 40 to 43.

49. A communication system, characterized in that Include one or more of the following: a first mobility management network element, configured to execute the method according to any one of claims 25 to 30; a first session management network element, configured to perform the method according to any one of claims 31 to 35; A second mobility management network element, wherein the second mobility management network element is configured to execute the method according to any one of claims 36 to 39; or A second session management network element, wherein the second session management network element is configured to execute the method according to any one of claims 40 to 43.

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