CN116074801A

CN116074801A - Communication system, communication method, and communication device

Info

Publication number: CN116074801A
Application number: CN202111276789.XA
Authority: CN
Inventors: 应江威; 杨艳梅; 张万强; 谭仕勇
Original assignee: Huawei Technologies Co Ltd
Current assignee: Huawei Technologies Co Ltd
Priority date: 2021-10-29
Filing date: 2021-10-29
Publication date: 2023-05-05
Also published as: WO2023071974A1

Abstract

The 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 a second network communicate through a communication interface; the communication system includes: the control plane device is used for forwarding 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 for providing control plane functions for the terminal device, wherein the second control plane device is a device deployed in a second network; and under the condition that the second control plane device no longer provides service for the terminal device, the first control plane device is used for transmitting control plane signaling with the first communication device, and the first control plane device is also used for providing control plane functions for the terminal device. By the method and the device, the network can provide services for the user.

Description

Communication system, communication method, and communication device

Technical Field

The present application relates to the field of communications, and more particularly, to a communication system, a communication method, and a communication apparatus.

Background

Currently, more and more enterprises have the described solution of independently networking. One possible deployment of enterprise private networks is a public network integrated non-public network (PNI-NPN). Specifically, the public land mobile network (public land mobile network, PLMN) deploys dedicated network slices for enterprises and deploys user plane function (user plane function, UPF) network elements to the enterprise campus and control plane network elements to operator core nodes (e.g., city-level machine rooms) taking into account the localization characteristics of the enterprise traffic. The public network and the enterprise private network communicate through a network interface to jointly provide services to the user.

The network interface between the public network and the enterprise private network may fail, which may result in the PNI-NPN not serving its users. Once the user and PNI-NPN are disconnected, it may result in interruption of the service currently in progress by the user, causing significant loss of the enterprise product line.

Disclosure of Invention

The application provides a communication system, a communication method and a communication device, which enable a network to provide services for users.

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 through a communication interface; the communication system includes: the control plane device is used for forwarding 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 for providing control plane functions for the terminal device, wherein the second control plane device is a device deployed in a second network; and under the condition that the second control plane device no longer provides service for the terminal device, the first control plane device is used for transmitting control plane signaling with the first communication device, and the first control plane device is also used for providing control plane functions for the terminal device.

In an example, the case where the second control plane provides services for the terminal device may include: the communication interface is connected normally; accordingly, the case where the second control plane no longer provides services for the terminal device may include: the above-mentioned communication interface connection failure.

As yet another example, the case where the second control plane provides services for the terminal device may include: the security privacy of the business of the terminal equipment is lower; accordingly, the case where the second control plane no longer provides services for the terminal device may include: and the security privacy of the service of the terminal equipment is higher.

As yet another example, the case where the second control plane provides services for the terminal device may include: a situation in which the network of the second network is not congested; accordingly, the case where the second control plane no longer provides services for the terminal device may include: and (3) a network congestion situation of the second network. Alternatively, the case where the second control plane provides services for the terminal device may include: a network congestion condition of the first network; accordingly, the case where the second control plane no longer provides services for the terminal device may include: and (3) a situation that the network of the first network is not congested.

Based on the above scheme, by deploying the first control plane device in the first network, when the second control plane device provides services for the terminal device, the first control plane device may act as a proxy device (or referred to as a proxy node) between the first communication device and the second control plane device, and forward signaling between the first communication device and the second control plane device. The first control plane device may perform control plane functions to control the terminal device when the second control plane device is no longer providing services to the terminal device. Therefore, the network can provide service for the user, so that the stable operation of the user service can be ensured as much as possible, and the continuity of the user service is realized. Taking the communication interface as an example, when the communication interface between two networks (such as the first network and the second network) is normal, the first control plane device may serve as a proxy device (or referred to as a proxy node) between the first communication device and the second control plane device, and forward 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 execute the control plane function to control the terminal device, so that the situation that the terminal device cannot be connected to the first network after the communication interface between the first network and the second network fails is avoided. Therefore, when the communication interface connection between the first network and the second network is normal, normal communication between the first communication equipment and the second control plane equipment is not affected, and when the communication interface connection between the first network and the second network is faulty, the service of the terminal equipment can be continuously and normally performed.

With reference to the first aspect, in some implementations of the first aspect, in a case that the second control plane device provides a service for the terminal device, the first control plane device is further configured to obtain an association identifier of the terminal device.

Based on the above scheme, the second control plane device obtains the association identifier of the terminal device when providing service for the terminal device, so that after the second control plane device no longer provides service for the terminal device, the signaling of the terminal device can be identified based on the association identifier of the terminal device, so as to provide service for the terminal device. In addition, the signaling of the terminal equipment is identified based on the association identifier of the terminal equipment, and the method is simple and easy to implement.

With reference to the first aspect, in some implementation manners of the first aspect, the first control plane device is further configured to obtain an association identifier of the terminal device, and the method includes: and the first control plane device is used for receiving the association identifier of the terminal device from the second control plane device.

Based on the above scheme, when the second control plane device provides service for the terminal device, the first control plane device can acquire the association identifier of the terminal device from the second control plane device, and the first control plane device is not required to generate or establish the association identifier of the terminal device, so that the requirement on the first control plane device is not high.

With reference to the first aspect, in some implementations of the first aspect, in a case where the second control plane device provides a service for the terminal device, the first control plane device is further configured to receive a first message from the second control plane device; and the first control plane device is further used for storing the context information of the terminal device according to the first message, wherein the context information of the terminal device has an association relationship with the association identifier of the terminal device.

Based on the scheme, the first control plane device stores 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 acquire 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.

With reference to the first aspect, in some implementations of the first aspect, in a case where the second control plane device no longer provides a service for the terminal device, the method further includes: the first control plane device is further configured to obtain context information of the terminal device through an association identifier of the terminal device.

Based on the above scheme, after the second control plane device no longer provides service for the terminal device, the context information of the terminal device can be quickly obtained 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, so as to maintain the normal operation of the service.

With reference to the first aspect, in certain implementations of the first aspect, the association identifier of the terminal device is any one of the following: user permanent identity, globally unique temporary identity, private identity, N3 tunnel identity.

With reference to the first aspect, in some implementations of the first aspect, the first communication device includes a source access network device, the communication system further includes a target access network device, and the first control plane device is further configured to switch the terminal device from the source access network device to the target access network device in a case where the second control plane device no longer provides services for the terminal device.

Based on the above scheme, the first control plane device can execute a switching process for the terminal device, so that the occurrence that the terminal device cannot switch from the source access network device to the target access network device after the second control plane device no longer provides service for the terminal device can be avoided as far as possible.

With reference to the first aspect, in certain implementation manners of the first aspect, the first communication device further includes a user plane function network element, and the first control plane device 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 used for receiving a switching request message from the target access network device, wherein the switching request message comprises N3 tunnel information distributed by the target access network device for the terminal device; the first control plane device is used for acquiring the association identifier of the terminal device; and the first control plane device is used for sending the N3 tunnel information to the user plane function network element based on the association identifier of the terminal device.

With reference to the first aspect, in certain 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 configured to obtain an association identifier of the terminal device, and includes: the first mobile management network element is used for acquiring the association identifier of the terminal equipment and sending the association identifier of the terminal equipment to the first session management network element; the first session management network element is used for receiving the association identifier of the terminal equipment from the first mobile management network element; the first control plane device is configured to send N3 tunnel information to the user plane functional network element based on the association identifier of the terminal device, and includes: the first session management network element is configured to obtain 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, where the session modification request message includes N3 tunnel information.

With reference to the first aspect, in some implementations of the first aspect, if the second control plane device does not provide services for the terminal device any more, the first control plane device is further configured to trigger a path switching procedure for the terminal device, so that the terminal device establishes a communication connection with the second control plane device.

With reference to the first aspect, in some implementations of the first aspect, the first control plane device is configured to provide a control plane function for a terminal device based on a security parameter, where the security parameter is a security parameter when the second control plane device provides the control plane function for the terminal device.

Based on the above scheme, the first control plane device may not generate a new security parameter (such as an intermediate key) for the terminal device, so that when the second control plane device no longer provides services for the terminal device, the first control plane device provides a control plane function for the terminal device, and the requirement on the first control plane device can be reduced, and the change on the existing protocol is small.

With reference to the first aspect, in certain implementations of the first aspect, the first control plane device includes: the first mobility management network element and/or the first session management network element.

With reference to the first aspect, in certain implementation manners of the first aspect, the first network is a local network of a public network integrated non-public network, and the second network is a central network of the public network integrated non-public network.

With reference to the first aspect, in certain implementation manners of the first aspect, the communication interface includes an N2 interface and/or an N4 interface.

With reference to the first aspect, in some implementations of the first aspect, the first communication device includes a user plane function network element, and if the second control plane device does not provide service for the terminal device any more, the user plane function network element provides the user plane function for the terminal device based on an N3 tunnel identifier, where the N3 tunnel identifier is a previous identifier, after the second control plane device provides service for the terminal device again.

Based on the above scheme, if the second control plane device does not provide service for the terminal device any more, after the second control plane device provides service for the terminal device again, the user plane function network element may provide the user plane function 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 may not need to perform a session modification procedure with the user plane function network element, or may not need to send the N3 tunnel identifier to the user plane function network element when the first session management network element performs a session modification procedure with the user plane function network element.

In a second aspect, a communication method is provided. The method comprises the following steps: in the case that the second control plane device deployed in the second network provides services for the terminal device, forwarding, by the first control plane device deployed in the first network, control plane signaling of the terminal device transmitted between the first communication device and the second control plane device deployed in the first network, where the second control plane device is configured to provide control plane functions for the terminal device; and under the condition that the second control plane equipment does not provide service for the terminal equipment any more, the control plane signaling is transmitted between the first control plane equipment and the first communication equipment, and the first control plane equipment provides control plane functions for the terminal equipment.

With reference to the second aspect, in some implementations of the second aspect, 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.

With reference to the second aspect, in some implementations of the second aspect, the first control plane device obtains an association identifier of the terminal device, including: the first control plane device receives the association identification from the terminal device of the second control plane device.

With reference to the second aspect, in some implementations of the second aspect, 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; and the first control plane device stores the context information of the terminal device according to the first message, wherein the context information of the terminal device has an association relationship with the association identifier of the terminal device.

With reference to the second aspect, in some implementations of the second aspect, 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.

With reference to the second aspect, in certain implementations of the second aspect, the association identifier of the terminal device is any one of the following: user permanent identity, globally unique temporary identity, private identity, N3 tunnel identity.

With reference to the second aspect, in some implementations of the second aspect, the first communication device includes a source access network device, the first network further includes a target access network device, and 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 switches the terminal device from the source access network device to the target access network device.

With reference to the second aspect, in some implementations of the second aspect, 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 switching request message from the target access network device, wherein the switching request message comprises N3 tunnel information distributed by the target access network device for the terminal device; the first control plane device acquires the association identifier of the terminal device; 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.

With reference to the second aspect, in certain 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 an association identifier of the terminal device, including: the first mobile management network element acquires the association identifier of the terminal equipment and sends the association identifier of the terminal equipment to the first session management network element; the first session management network element receives the association identifier of the terminal equipment from the first mobile 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, and the method includes: the first session management network element obtains the context information of the terminal equipment according to the association identifier of the terminal equipment, and sends a session modification request message to the user plane function network element, wherein the session modification request message comprises N3 tunnel information.

With reference to the second aspect, in certain implementations of the second aspect, the method further includes: and under the condition that the second control plane equipment does not provide service for the terminal equipment any more, if the second control plane equipment provides service for the terminal equipment again, the first control plane equipment triggers a path switching flow for the terminal equipment so that the terminal equipment is connected to the second control plane equipment.

With reference to the second aspect, in certain implementations of the second aspect, the method further includes: the first control plane device provides a control plane function for the terminal device based on a security parameter, wherein the security parameter is the security parameter when the second control plane device provides the control plane function for the terminal device.

With reference to the second aspect, in certain implementations of the second aspect, the first control plane device includes: the first mobility management network element and/or the first session management network element.

With reference to the second aspect, in some implementations of the second aspect, the first network is a local network of a public network integrated non-public network, and the second network is a central network of the public network integrated non-public network.

With reference to the second aspect, in certain implementations of the second aspect, the communication interface includes an N2 interface and/or an N4 interface.

In a third aspect, a communication method is provided. The method may be performed by the network device or may be performed by a component (e.g. a chip or a circuit) of the network device, which is not limited, and is described below as being performed by the first mobility management element for convenience of description.

The method comprises the following steps: the first mobility management network element acquires an association identifier of the terminal equipment, wherein the association identifier of the terminal equipment is used for identifying the terminal equipment when second control plane equipment deployed in a second network does not provide service for the terminal equipment any more; the first mobile management network element sends the association identifier of the terminal equipment to the 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.

Based on the above scheme, 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, where the association identifier of the terminal device is used to identify the terminal device when the second control plane device no longer provides service for the terminal device, so that when the second control plane device no longer provides service for the terminal device, the first mobility management network element and the first session management network element can identify 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 service for the terminal device, the service of the terminal device can continue to be performed normally.

With reference to the third aspect, in some implementations of the third aspect, 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 an association identification from a terminal device of a second mobility management network element, the second mobility management network element being deployed in the second network.

Based on the above scheme, when the second control plane device provides service for the terminal device, the first mobility management network element can obtain the association identifier of the terminal device from the second mobility management network element, and the first mobility management network element is not required to generate or establish the association identifier of the terminal device, so that the requirement on the first mobility management network element is not high.

With reference to the third aspect, in some implementations of the third aspect, 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 stores the context information of the terminal equipment according to the first message, and the context information of the terminal equipment has an association relationship with the association identifier of the terminal equipment.

Based on the above scheme, the first mobility management network element stores 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 mobility management network element can quickly acquire 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.

With reference to the third aspect, in some implementations of the third aspect, the first mobility management network element obtains an association identifier of the terminal device, including: under the condition that the second control plane equipment does not provide service for the terminal equipment any more, the first mobile management network element identifies the context of the terminal equipment according to the control plane port identification, wherein the control plane port identification is the port identification of the control plane interface between the first mobile management network element and the access network equipment; the first mobility management network element obtains the association identifier of the terminal equipment according to the context of the terminal equipment.

With reference to the third aspect, in certain implementations of the third aspect, the method further includes: and under the condition that the second control plane equipment does not provide service for the terminal equipment any more, if the second control plane equipment provides service for the terminal equipment again, the first mobile management network element triggers a path switching flow for the terminal equipment so as to establish communication connection between the terminal equipment and the second session management network element and/or the second mobile management network element, wherein the second session management network element and the second mobile management network element are deployed in a second network.

With reference to the third aspect, in certain implementations of the third aspect, the method further includes: the first mobility management network element provides a control plane function for the terminal device based on a security parameter, wherein the security parameter is a security parameter when the second mobility management network element provides the control plane function for the terminal device.

Based on the above scheme, the first mobility management network element may not generate a new security parameter (such as an intermediate key) for the terminal device, so that not only can the first mobility management network element provide a control plane function for the terminal device when the second control plane device no longer provides services for the terminal device, but also the requirement on the first mobility management network element can be reduced, and the modification on the existing protocol is small.

With reference to the third aspect, in some implementations of the third aspect, the association identifier of the terminal device is any one of the following: user permanent identity, globally unique temporary identity, private identity, N3 tunnel identity.

In a fourth aspect, a communication method is provided. The method may be performed by the network device or may be performed by a component (e.g., a chip or a circuit) of the network device, which is not limited thereto, and is described below as being performed by the first session management network element for convenience of description.

The method comprises the following steps: the first session management network element receives an association identifier of a terminal device from the first mobility management network element, wherein the association identifier of the terminal device is used for identifying 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 service for the terminal device, the first session management network element identifies the session context associated with the association identifier of the terminal device according to 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.

Based on the above scheme, by deploying the 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, where the association identifier of the terminal device is used to identify the terminal device when the second control plane device no longer provides service for the terminal device, so that when the second control plane device no longer provides service 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 service for the terminal device, the service of the terminal device can continue to be performed normally.

With reference to the fourth aspect, in some implementations of the fourth aspect, 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 an association identification from a terminal device of a second session management network element, the second mobility management network element being deployed in the second network.

With reference to the fourth aspect, in some implementations of the fourth aspect, 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, the second session management network element being deployed in a second network; the first session management network element stores the context information of the terminal equipment according to the first message, and the context information of the terminal equipment has an association relationship with the association identifier of the terminal equipment.

Based on the above scheme, the first session management network element stores 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 session management network element can quickly acquire 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.

With reference to the fourth aspect, in some implementations of the fourth aspect, 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 equipment according to the association identifier of the terminal equipment, and sends a session modification request message to the user plane function network element.

With reference to the fourth aspect, in some implementations of the fourth aspect, the association identifier of the terminal device is any one of the following: user permanent identity, globally unique temporary identity, private identity, N3 tunnel identity.

In a fifth aspect, a communication method is provided. The method may be performed by the network device or may be performed by a component (e.g. a chip or a circuit) of the network device, which is not limited, and is described below as being performed by the second mobility management element for convenience of description.

The method comprises the following steps: the second mobility management network element determines an association identifier of the terminal device, wherein the association identifier of the terminal device is used for identifying the terminal device when a second control plane device deployed in a second network no longer provides service for the terminal device; the second mobility management network element sends the association identifier of the terminal equipment to the first mobility management network element; wherein the first mobility management network element is deployed in a first network and the second mobility management network element is deployed in a second network.

Based on the above scheme, the second mobility management network element deployed in the second network sends the association identifier of the terminal device to the first mobility management network element deployed in the first network, where the association identifier of the terminal device is used to identify the terminal device when the second control plane device no longer provides service for the terminal device, so that when the second control plane device no longer provides service for the terminal device, the first mobility management network element can identify 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 service for the terminal device, the service of the terminal device can continue to be performed normally.

With reference to the fifth aspect, in certain implementation manners of the fifth aspect, the determining, by the second mobility management network element, the association identifier of the terminal device includes: if the network slice supported by the terminal device and/or the first network has a robustness requirement, the second mobility management network element determines the association identifier of the terminal device.

With reference to the fifth aspect, in certain implementations of the fifth aspect, the method further includes: the second mobility management network element sends the association identifier of the terminal device to a second session management network element, which is deployed in the second network.

With reference to the fifth aspect, in certain implementations of the fifth aspect, the association identifier of the terminal device is any one of the following: user permanent identification, globally unique temporary identification, private identification.

With reference to the fifth aspect, in some implementations of the fifth aspect, in a 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 second mobility management network element provides the control plane function for the terminal device based on a security parameter, where the security parameter is a security parameter when the second mobility management network element provides the control plane function for the terminal device before the second control plane device no longer provides services for the terminal device occurs.

In a sixth aspect, a communication method is provided. The method may be performed by the network device or may be performed by a component (e.g., a chip or a circuit) of the network device, which is not limited, and is described below as being performed by the second session management network element for convenience of description.

The method comprises the following steps: the second session management network element obtains an association identifier of the terminal equipment, wherein the association identifier of the terminal equipment is used for identifying the terminal equipment when second control plane equipment deployed in a second network does not provide service for the terminal equipment any more; the second session management network element sends the association identifier of the terminal equipment to the first session management network element; wherein the first session management network element is deployed in a first network and the second session management network element is deployed in a second network.

Based on the above scheme, 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, where the association identifier of the terminal device is used to identify the terminal device when the second control plane device no longer provides service for the terminal device, so that when the second control plane device no longer provides service for the terminal device, the first session management network element can identify 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 service for the terminal device, the service of the terminal device can continue to be performed normally.

With reference to the sixth aspect, in certain implementations of the sixth aspect, the method further includes: if the network slice supported by the terminal equipment or the first network has the robustness requirement, the second session management network element sends the association identifier of the terminal equipment to the user plane function network element, and the user plane function network element is deployed in the first network.

With reference to the sixth aspect, in some implementations of the sixth aspect, the second session management network element obtains an association identifier of the terminal device, including: the second session management network element receives the association identification from the terminal device of the second mobility management network element, the second mobility management network element being deployed in the second network.

With reference to the sixth aspect, in certain implementations of the sixth aspect, the association identifier of the terminal device is any one of the following: user permanent identification, globally unique temporary identification, private identification.

A seventh aspect provides a communication device for performing the method of any one of the possible implementations of the second to sixth aspects. In particular, the apparatus may comprise means and/or modules, such as a processing unit and/or a communication unit, for performing the method in any of the possible implementations of the second aspect to the sixth aspect.

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

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

In an eighth aspect, there is provided a communication apparatus comprising: at least one processor configured to execute a computer program or instructions stored in a memory to perform a method according to any one of the possible implementations of the second to sixth aspects described above. Optionally, the apparatus further comprises a memory for storing a computer program or instructions. Optionally, the apparatus further comprises a communication interface through which the processor reads the computer program or instructions stored in the memory.

In one implementation, the apparatus is a network device (e.g., a control plane device, such as a mobility management network element, such as a session management network element).

In another implementation, the apparatus is a chip, a system-on-chip, or a circuit for a network device (e.g., a control plane device, such as a mobility management network element, such as a session management network element).

In a ninth aspect, the present application provides a processor configured to perform the method provided in the above aspects.

The operations such as transmitting and acquiring/receiving, etc. related to the processor may be understood as operations such as outputting and receiving, inputting, etc. by the processor, or may be understood as operations such as transmitting and receiving by the radio frequency circuit and the antenna, if not specifically stated, or if not contradicted by actual function or inherent logic in the related description, which is not limited in this application.

In a tenth aspect, a computer readable storage medium is provided, the computer readable storage medium storing program code for execution by a device, the program code comprising instructions for performing the method of any one of the possible implementations of the second to sixth aspects described above.

In an eleventh aspect, there is provided a computer program product comprising instructions which, when run on a computer, cause the computer to perform the method of any one of the possible implementations of the second to sixth aspects described above.

A twelfth aspect provides a communication system comprising one or more of the aforementioned first mobility management element, second mobility management element, first session management element, second session management element.

In a thirteenth aspect, a communication system is provided, which includes one or more of the aforementioned first control plane device, the second mobility management element, and the second session management element.

Drawings

Fig. 1 shows a schematic diagram of a network architecture suitable for use in embodiments of the present application.

Fig. 2 shows a schematic diagram of a non-public network.

Figure 3 shows a schematic diagram of PNI-NPN.

Fig. 4 is a schematic diagram of a communication system 400 according to an embodiment of the present application.

Fig. 5 shows a schematic diagram of a network architecture provided according to an embodiment of the present application.

Fig. 6 shows a schematic diagram of a communication method 600 provided in an embodiment of the present application.

Fig. 7 shows a schematic flow chart of a communication method 700 provided in an embodiment of the present application.

Fig. 8 shows a schematic flow chart of a communication method 800 provided in an embodiment of the present application.

Fig. 9 shows a schematic flow chart of a communication method 900 provided in an embodiment of the present application.

Fig. 10 shows a schematic flow chart of a communication method 1000 provided in an embodiment of the present application.

Fig. 11 shows a schematic flow chart diagram of a communication method 1100 provided by an embodiment of the present application.

Fig. 12 shows a schematic block diagram of a communication apparatus 1200 provided in an embodiment of the present application.

Fig. 13 shows a schematic block diagram of another communication device 1300 provided by an embodiment of the present application.

Fig. 14 shows a schematic diagram of a chip system 1400 provided in an embodiment of the present application.

Detailed Description

The technical solutions in the present application will be described below with reference to the accompanying drawings.

The technical solution of the embodiment of the application can be applied to various communication systems, for example: fifth generation (5th generation,5G) or New Radio (NR) systems, satellite communications, long term evolution (long term evolution, LTE) systems, LTE frequency division duplex (frequency division duplex, FDD) systems, LTE time division duplex (time division duplex, TDD), and the like. The technical scheme provided by the application can also be applied to future communication systems, such as a sixth generation mobile communication system. The technical solutions of the embodiments of the present application may also be applied to device-to-device (D2D) communication, vehicle-to-device (V2X) communication, machine-to-machine (machine to machine, M2M) communication, machine type communication (machine type communication, MTC), industrial control, intelligent transportation systems (intelligent transportation system, ITS), mobile broadband, multimedia and internet of things (internet of things, ioT) communication systems or other communication systems.

To facilitate understanding of embodiments of the present application, a network architecture suitable for use in embodiments of the present application will be described in detail first with reference to fig. 1 and 2.

As an exemplary illustration, fig. 1 shows a schematic diagram of a network architecture suitable for use in embodiments of the present application. As shown in fig. 1, the network architecture may include, for example, but is not limited to, the following: a network slice selection function (network slice selection function, NSSF) (i.e., one instance of a slice management network element), AN authentication service function (authentication server function, AUSF) (i.e., one instance of AN authentication server function network element), unified data management (unified data management, UDM) (i.e., one instance of a data management network element), access and mobility management functions (access and mobility management function, AMF) (i.e., one instance of AN access management network element), session management functions (session management function, SMF) (i.e., one instance of a session management network element), policy control functions (policy control function, PCF) (i.e., one instance of a policy control network element), application functions (application function, AF) (i.e., one instance of AN application network element), user Equipment (UE), access Networks (AN), user plane functions (user plane function, UPF) (i.e., one instance of a user plane network element), data networks (data networks, DN), etc.

The following briefly describes the network elements shown in fig. 1.

1. UE: a terminal device, access terminal, subscriber unit, subscriber station, mobile station, remote terminal, mobile device, user terminal, wireless communication device, user agent, or user equipment may be referred to as a terminal device.

The terminal device may be a device that provides voice/data to a user, e.g., a handheld device with wireless connection, an in-vehicle device, etc. Currently, some examples of terminals are: a mobile phone, tablet, laptop, palmtop, mobile internet device (mobile internet device, MID), wearable device, virtual Reality (VR) device, augmented reality (augmented reality, AR) device, wireless terminal in industrial control (industrial control), wireless terminal in unmanned (self driving), wireless terminal in teleoperation (remote medical surgery), wireless terminal in smart grid (smart grid), wireless terminal in transportation security (transportation safety), wireless terminal in smart city (smart city), wireless terminal in smart home (smart home), cellular phone, cordless phone, session initiation protocol (session initiation protocol, SIP) phone, wireless local loop (wireless local loop, WLL) station, personal digital assistant (personal digital assistant, PDA), handheld device with wireless communication function, computing device or other processing device connected to wireless modem, wearable device, terminal device in 5G network or terminal in future evolved land mobile communication network (public land mobile network), and the like, without limiting the present application.

By way of example, and not limitation, in embodiments of the present application, the terminal device may also be a wearable device. The wearable device can also be called as a wearable intelligent device, and is a generic name for intelligently designing daily wear by applying wearable technology and developing wearable devices, such as glasses, gloves, watches, clothes, shoes and the like. The wearable device is a portable device that is worn directly on the body or integrated into the clothing or accessories of the user. The wearable device is not only a hardware device, but also can realize a powerful function through software support, data interaction and cloud interaction. The generalized wearable intelligent device includes full functionality, large size, and may not rely on the smart phone to implement complete or partial functionality, such as: smart watches or smart glasses, etc., and focus on only certain types of application functions, and need to be used in combination with other devices, such as smart phones, for example, various smart bracelets, smart jewelry, etc. for physical sign monitoring.

In addition, in the embodiment of the application, the terminal device may also be a terminal device in an IoT system, where IoT is an important component of future information technology development, and the main technical feature is to connect the article with a network through a communication technology, so as to implement man-machine interconnection and an intelligent network for interconnecting the articles.

It should be noted that, some air interface technology (such as NR or LTE technology) may be used to communicate between the terminal device and the access network device. The terminal equipment and the terminal equipment can also communicate with each other by adopting a certain air interface technology (such as NR or LTE technology).

In the embodiment of the present application, the device for implementing the function of the terminal device may be the terminal device, or may be a device capable of supporting the terminal device to implement the function, for example, a chip system or a chip, and the device may be installed in the terminal device. In the embodiment of the application, the chip system may be formed by a chip, and may also include a chip and other discrete devices.

2. (radio) access network (R) AN) device: the authorized users of the specific area may be provided with the functionality to access the communication network, which may specifically include wireless network devices in a third generation partnership project (3rd generation partnership project,3GPP) network or may include access points in a non-3GPP (non-3 GPP) network. The following description will be presented using AN apparatus for convenience of description.

AN device may employ different radio access technologies. There are two types of current radio access technologies: 3GPP access technologies (e.g., third generation (3rd generation,3G), fourth generation (4th generation,4G), or wireless access technologies employed in 5G systems) and non-3GPP (non-3 GPP) access technologies. The 3GPP access technology refers to an access technology conforming to the 3GPP standard specification, for example, access network devices in a 5G system are referred to as next generation base station nodes (next generation Node Base station, gNB) or RAN devices. Non-3GPP access technologies can include air interface technologies typified by an Access Point (AP) in Wireless Fidelity (wireless fidelity, wiFi), worldwide interoperability for microwave Access (worldwide interoperability for microwave access, wiMAX), code division multiple Access (code division multiple access, CDMA), and so forth. The AN device may allow interworking between the terminal device and the 3GPP core network using non-3GPP technology.

The AN device can be responsible for radio resource management, quality of service (quality of service, qoS) management, data compression, encryption, and other functions on the air interface side. The AN equipment provides access service for the terminal equipment, and further, the forwarding of control signals and user data between the terminal equipment and the core network is completed.

AN devices may include, for example, but are not limited to: macro base stations, micro base stations (also called small stations), radio network controllers (radio network controller, RNC), node bs (Node bs, NB), base station controllers (base station controller, BSC), base transceiver stations (base transceiver station, BTS), home base stations (e.g., home evolved NodeB, or home Node bs, HNB), base Band Units (BBU), APs in WiFi systems, wireless relay nodes, wireless backhaul nodes, transmission points (transmission point, TP), or transmission reception points (transmission and reception point, TRP), etc., as well as a gNB or transmission points (TRP or TP) in 5G (e.g., NR) systems, an antenna panel of one or a group (including multiple antenna panels) of base stations in 5G systems, or as well as network nodes constituting a gNB or transmission point, such as a Distributed Unit (DU), or a base station in next generation communication 6G systems, etc. The embodiment of the application does not limit the specific technology and the specific equipment form adopted by the AN equipment.

3. Access management network element: the method is mainly used for the functions of access control, mobility management, attachment and detachment and the like. The access management network element may also serve as an anchor point for connection of N1 signaling (i.e., signaling of the N1 interface, abbreviated as N1 signaling for brevity) and N2 signaling (i.e., signaling of the N2 interface, abbreviated as N2 signaling for brevity), and provide routing of N1/N2 session management (session management, SM) messages for the session management network element. The access management network element may also maintain and manage state information for the UE.

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

4. Session management network element: the method is mainly used for user plane network element selection, user plane network element redirection, internet protocol (internet protocol, IP) address allocation of terminal equipment, session establishment, modification and release and QoS control.

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.

5. User plane network element: the method is mainly used for receiving and forwarding the user plane data. For example, the user plane network element may receive user plane data from the DN and send the user plane data to the terminal device through the AN device. The user plane network element may also receive user plane data from the terminal device through the AN device and forward to the DN.

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.

6. Policy control network element: the unified policy framework is mainly used for guiding network behaviors, and provides policy rule information and the like for control plane network elements (such as access management network elements, session management network elements and the like).

In a 4G communication system, the policy control network element may be a policy and charging rules function (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.

7. Application network element: the method is mainly used for providing services for the 3GPP network, such as interaction with a policy control network element for policy control and the like.

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.

8. Data management network element: the method is mainly used for subscription data management of the UE, and comprises storage and management of the UE identification, access authorization of the UE and the like. The data management network element may also generate authentication credentials for the UE for 3 GPP. The data management network element may also register to maintain the network element currently serving the UE (e.g., AMF represented by AMF ID1 is the current service AMF (serving AMF) of the UE).

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

9. Data network: the method is mainly used for an operator network for providing data services for the UE. Such as the Internet, a third party's service network, an IP Multimedia Services (IMS) network, etc.

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.

10. Authentication server function network element: the method is mainly used for user authentication and the like, such as safety authentication of the UE when the UE accesses the network.

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 is not limited in this application.

11. Slice management network element: the method is mainly used for selecting a slice instance set for the UE, determining an AMF set and allowed network slice selection auxiliary information (network slice selection assistance information, NSSAI) (NSSAIs) for the UE.

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.

In the network architecture shown in fig. 1, the network elements may communicate through interfaces shown in the figure, and part of the interfaces may be implemented by using a service interface. As shown in fig. 1, communication between the UE and the AMF may be performed through an N1 interface. Communication between the RAN and the AMF may be via an N2 interface. Communication between the RAN and the UPF may be performed through an N3 interface, and the N3 interface may be used to transmit data of the user plane, etc. The SMF and the UPF may communicate through an N4 interface, and the N4 interface may be used to transmit information such as tunnel identification information of the N3 connection, data buffer indication information, and a downlink data notification message. The relationship between his interface and the various network elements is shown in fig. 1 and will not be described in detail here for the sake of brevity.

It should be understood that the network architecture shown above is merely an exemplary illustration, and the network architecture to which the embodiments of the present application apply is not limited, and any network architecture capable of implementing the functions of the various network elements described above is applicable to the embodiments of the present application.

It should also be understood that AMF, SMF, UPF, PCF, UDM, NSSF, AUSF and the like shown in fig. 1 may be understood as network elements for implementing different functions, for example, may be combined into network slices as required, where the network elements may be independent devices, may be integrated into the same device to implement different functions, or may be network elements in hardware devices, may be software functions running on dedicated hardware, or be virtualized functions instantiated on a platform (for example, a cloud platform), and the specific form of the network elements is not limited in this application.

It should also be appreciated that the network elements or functions described above may be partitioned into one or more services, and further that services that exist independently of the network functions may also occur. In this application, an instance of the above-described function, or an instance of a service included in the above-described function, or an instance of a service existing independently of a network function may be referred to as a service instance. In addition, in actual deployment, network elements with different functions can be combined. For example, the access and mobility management network element may be collocated with the session management network element; the session management network element may be co-located with the user plane network element. When two network elements are combined, the interaction between the two network elements provided in the embodiments of the present application becomes the internal operation of the combined network element or may be omitted.

It should also be understood that the above designations are merely defined to facilitate distinguishing between different functions and should not be construed as limiting the present application in any way. The present application does not exclude the possibility of using other designations in 6G networks as well as other networks in the future. For example, in a 6G network, some or all of the individual network elements may follow the terminology in 5G, possibly by other names, etc.

It should also be understood that the names of interfaces between the network elements in fig. 1 are only an example, and the names of interfaces in the specific implementation may be other names, which are not specifically limited in this application. Furthermore, the names of the transmitted messages (or signaling) between the various network elements described above are also merely an example, and do not constitute any limitation on the function of the message itself.

As an exemplary illustration, fig. 2 shows a schematic diagram of a non-public network (NPN).

Currently, more and more enterprises have the described solution of independently networking. The non-public network is mainly used for the vertical industry scene of enterprises and serves the business of the enterprises. As shown in fig. 2, the NPN deployment configuration includes at least the following two types.

1) Independent NPN (stand alone NPN, SNPN): NPN enterprise business services are provided independently of the PLMN public network of the operator. The SNPN can be deployed and operated by an NPN operator or a PLMN operator. As shown in fig. 2 (1), in the SNPN, the SNPN has an independent radio access network (radio access network, RAN) (e.g., gNB) and a core network (core net, CN) (control plane (e.g., referred to as SNPN CP), and user plane (e.g., referred to as SNPN UP)).

2) Public network integrated NPN (public network integrated NPN, PNI-NPN): non-independent NPN, deployment by PLMN operators, without establishing a physical network node dedicated to NPN, NPN can be defined using nsai or data network name (data network name, DNN). As shown in fig. 2 (2), services provided by a central network (or referred to as a public network, i.e., PLMN public network) may be identified by a PLMN Identification (ID), such as PLMN a, and services provided by a local network (or referred to as an enterprise private network or PNI-NPN) may be identified by a closed access group identification (closed access group, CAG) ID, such as CAG X.

Hereinafter, for convenience of description, a home network (or referred to as an enterprise private network) is denoted by PNI-NPN, and a center network (or referred to as a public network) of PNI-NPN is denoted by PLMN.

It should be understood that the two deployment approaches described above are exemplary only and are not limiting.

To meet widely varying traffic demands, communication networks will be constructed in a flexible manner. One possible way of constructing this is network function separation, such as Control Plane (CP) and User Plane (UP) function separation, MM and SM functions in CP separation. One common technique for implementing network function separation is the network slice (netslice) technique. Network slicing is a technique of cutting a physical network into multiple virtual end-to-end networks, each of which is logically independent. Each network slice is formed by an independent network function or function combination instantiation, has different functional characteristics, and is oriented to different requirements and services. The separation of the network slices enables different users and user groups to flexibly and dynamically define and customize network capacity according to different application scenes and requirements of the users and the user groups without affecting each other.

As an exemplary illustration, fig. 3 shows a schematic diagram of PNI-NPN.

As shown in fig. 3, PLMNs deploy dedicated network slices for enterprises and UPF network elements are deployed to enterprise parks considering the localization characteristics of enterprise traffic, but control plane network elements (e.g., AMFs, SMFs, etc.) are also at operator core nodes (e.g., city-level machine rooms). The public network and the enterprise private network can be connected through interfaces. For example, interworking is achieved between a UPF network element deployed in the enterprise campus and an SMF network element in the PLMN through an N4 interface, and interworking is achieved between a RAN (e.g., a gNB) deployed in the enterprise campus and an AMF network element in the PLMN through an N2 interface.

However, the physical interface between the public network and the enterprise private network may fail, e.g., the N2 interface is disconnected and/or the N4 interface is disconnected. After the N2 interface is disconnected and/or the N4 interface is disconnected, the UE cannot be connected to the network any more, i.e. it will fall back to an IDLE (IDLE) state, i.e. the UE and the PNI-NPN are disconnected. Once the UE and the PNI-NPN are disconnected, the service currently in progress by the UE will be interrupted, resulting in significant loss of the factory product line, failing to meet the requirements of the non-public network (or private network) for service robustness.

In view of this, the embodiment of the present application provides a solution, which can continuously maintain normal operation of basic services of the private network after a connection between the public network and the private network of the enterprise fails (e.g. the N2 interface and the N4 interface are disconnected).

It will be appreciated that the term "and/or" is merely one association relationship describing the associated object, and means that three relationships may exist, for example, a and/or B may mean: a exists alone, A and B exist together, and B exists alone. In addition, the character "/" herein generally indicates that the front and rear associated objects are an "or" relationship.

Various embodiments provided herein will be described in detail below with reference to the accompanying drawings.

The communication system 400 is deployed between a first network, where the first network and a second network communicate via a communication interface, or where interworking is achieved between the first network and the second network via a communication interface.

The communication system 400 includes: a first control plane device 410 and a first communication device 420.

In the case that the second control plane device provides services for the terminal device, the first control plane device 410 is configured to forward 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 configured to provide control plane functions for the terminal device, where the second control plane device is a device deployed in the second network.

In case the second control plane device no longer serves the terminal device, the first control plane device 410 is configured to transmit control plane signaling with the first communication device 420, and the first control plane device 410 is further configured to provide control plane functions for the terminal device.

It will be appreciated that the control plane signaling used by the first control plane device 410 to forward when the second control plane device provides a service (e.g., a control plane service) for the terminal device is identical to the control plane signaling used by the first control plane device 410 to transmit the control plane signaling with the first communication device 420 when the second control plane device no longer provides a service for the terminal device, where the control plane signaling mentioned in both locations is a generic term, and the application is not limited to the control plane signaling mentioned in both locations. As an example, the control plane signaling referred to herein may be identical, may be completely different, or may be partially identical.

It will be further understood that, in the case where the second control plane device provides service for the terminal device, the control plane function provided by the second control plane device for the terminal device is identical to the control plane function provided by the first control plane device 410 for the terminal device in the case where the second control plane device no longer provides service for the terminal device, where the two mentioned control plane functions are all generic terms, and the application is not limited to the two mentioned control plane functions being identical. As an example, the control plane functions mentioned in the two places may be identical, may be completely different, or may be partially identical.

Based on the above scheme, by deploying the first control plane device in the first network, when the second control plane device provides services for the terminal device, the first control plane device may serve as a proxy device (or referred to as a proxy node) between the first communication device and the second control plane device, and forward signaling between the first communication device and the second control plane device. The first control plane device may perform control plane functions to control the terminal device when the second control plane device is no longer providing services to the terminal device. Therefore, the network can provide service for the user, so that the stable operation of the user service can be ensured as much as possible, and the continuity of the user service is realized. 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 may act as a proxy device (or referred to as a proxy node) between the first communication device and the second control plane device, and forward 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 execute the control plane function to control the terminal device, so that the situation that the terminal device cannot be connected to the first network after the communication interface between the first network and the second network fails is avoided. Therefore, when the communication interface connection between the first network and the second network is normal, normal communication between the first communication equipment and the second control plane equipment is not affected, and when the communication interface connection between the first network and the second network is faulty, the service of the terminal equipment can be continuously and normally performed.

The second control plane device provides service for the terminal device, and the second control plane device no longer provides service for the terminal device, which means that in some cases, the second control plane device provides service for the terminal device, and in some cases, the second control plane device no longer provides service for the terminal device.

For example, the case where the second control plane provides services for the terminal device may include: the communication interface is connected normally; accordingly, the case where the second control plane no longer provides services for the terminal device may include: the above-mentioned communication interface connection failure. That is, the "case where the second control plane provides service to the terminal device" may be replaced with the "case where the communication interface between the first network and the second network is normal", the "case where the second control plane no longer provides service to the terminal device", and the "case where the communication interface between the first network and the second network is failed".

For another example, the case where the second control plane provides services for the terminal device may include: the security privacy of the business of the terminal equipment is lower; accordingly, the case where the second control plane no longer provides services for the terminal device may include: and the security privacy of the service of the terminal equipment is higher. That is, the "case where the second control plane provides services to the terminal device" may be replaced with the "case where the security privacy of the service of the terminal device is low", the "case where the second control plane no longer provides services to the terminal device", and the "case where the security privacy of the service of the terminal device is high".

For another example, the case where the second control plane provides services for the terminal device may include: a situation in which the network of the second network is not congested; accordingly, the case where the second control plane no longer provides services for the terminal device may include: and (3) a network congestion situation of the second network. That is, the "case where the second control plane provides the service to the terminal device" may be replaced with the "case where the network of the second network is not congested", the "case where the second control plane no longer provides the service to the terminal device", and the "case where the network of the second network is congested".

For another example, the case where the second control plane provides services for the terminal device may include: a network congestion condition of the first network; accordingly, the case where the second control plane no longer provides services for the terminal device may include: and (3) a situation that the network of the first network is not congested. That is, the "case where the second control plane provides service to the terminal device" may be replaced with "case where the network of the first network is congested", "case where the second control plane no longer provides service to the terminal device", and may be replaced with "case where the network of the first network is not congested".

It will be appreciated that the several cases described above are illustrative and the present application is not limited thereto. For example, any modification which belongs to the above-described case is applicable to the present application.

It will also be appreciated that the above-mentioned "the second control plane device no longer serves the terminal device" is not limited to "the second control plane device never serves the terminal device anymore", i.e. it means that in some cases the second control plane device temporarily no longer serves the terminal device.

Hereinafter, for convenience of understanding, the communication interface is mainly exemplified, and it will be understood that "the case where the communication interface is normally connected" may be replaced by "the case where the second control plane provides the service for the terminal device" and "the case where the communication interface is faulty" may be replaced by "the case where the second control plane no longer provides the service for the terminal device" hereinafter.

Alternatively, the first network is a non-public network (alternatively referred to as an enterprise private network, alternatively referred to as a local network), and the second network is a public network. Therefore, when the communication interface between the public network and the non-public network fails, the first control plane device in the non-public network provides a control plane function for the terminal device, thereby ensuring that the enterprise service continues to normally run and meeting the requirement of robustness of the non-public network.

For example, the first network is a local network of PNI-NPN and the second network is a central network of PNI-NPN (e.g. PLMN). The first network may be deployed by a second network, such as the second network deploys the UPF to the first network, with the control plane network element (i.e., the second control plane device) on the second network. The second control plane device may for example comprise a mobility management network element (for distinction called second mobility management network element) and a session management network element (for distinction called second session management network element). As an example, the second mobility management network element is an AMF. As an example, the second session management network element is an SMF.

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

For example, interworking is achieved between a UPF deployed in a first network and an SMF deployed in a second network via an N4 interface; as another example, interworking is achieved between a RAN (e.g., a gNB) deployed in a first network and an AMF in a second network via an N2 interface.

The communication interfacing failure between the first network and the second network may include, for example: communication interface disconnection, such as N2 interface disconnection and/or N4 interface disconnection; or may also include: the second network fails without limitation.

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., 3GPP standards) for communication between devices. In this regard, the description thereof will not be repeated.

The first control plane device 410, alternatively referred to as a Light-weight control plane (L-CP) function, may provide a control plane function for the terminal device. The control plane functions may be part or all of the functions of the second control plane device, such as may include mobility management functions and session management functions. The first control plane device 410 provides control plane functions for the terminal device, which may include, for example, the first control plane device 410 performing part of the control plane functions to control the terminal device. Wherein a partial function of the control plane, i.e. a partial function of the control plane functions, is represented. In addition, the first control plane device 410 provides a control plane function for the terminal device, and may further include transmitting control plane signaling of the terminal device between the first control plane device 410 and the first communication device 420.

Optionally, the first control plane device 410 comprises a mobility management network element (for distinction, referred to as a first mobility management network element) and a session management network element (for distinction, referred to as a first session management network element). 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, the AMF and SMF deployed in the first network are referred to herein as L-AMF and L-SMF, respectively.

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

It should be appreciated that the present application is not limited to 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.). As 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.).

Optionally, in case 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 association Identifier (ID) of the terminal device. The associated identifier of the terminal device may be used to identify the terminal device, or may be used to identify the terminal device in the event of a failure of the communication interface connection between the first network and the second network. For brevity, the association identifier of the terminal device will be referred to as UE ID hereinafter. Thus, in case of a failure of the communication interface connection between the first network and the second network, the first control plane device 410 may perform a signaling interaction on the communication interface for the terminal device based on the UE ID.

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 may instruct the first communication device 420 to regulate (or manipulate) the corresponding terminal device based on the UE ID.

For another example, when the first control plane device 410 includes multiple devices, for example, the first control plane device 410 includes L-AMF and L-SMF, the L-AMF and the L-SMF may perform signaling interaction, and thus the L-AMF and the L-SMF may identify the same terminal device through the UE ID.

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 has an association relationship (or correspondence relationship) with the UE ID. Therefore, when the communication interface between the first network and the second network fails, the first control plane device may be configured to acquire the context information of the corresponding terminal device through the UE ID.

Wherein, the association form of the context information about 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 UE ID is associated with the context information of the terminal device. It should be understood that the present application is not limited in terms of the specific form of association, as long as the UE ID associated with the context information of the terminal device can be known from the context information of the terminal device; or, according to the UE ID, acquiring the context information of the terminal equipment associated with the UE ID is applicable to the application.

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 configured to obtain, from the second control plane device, context information of a terminal device, where the context information of the terminal device has an association relationship with the UE ID. For another example, when the communication interface between the first network and the second network is normal, the first control plane device 410 is configured to receive a first message (such as a context establishment request message, and also such as a session establishment request message) from the second control plane device, and establish context information of the terminal device according to the first message, and store the context information of the terminal device, where the context information of the terminal device has an association relationship with the UE ID.

The first control plane device 410 obtains the UE ID and performs signaling interaction on the communication interface for the terminal device based on the UE ID, which will be described in detail later with reference to fig. 7 to 10.

Optionally, the UE ID is any one of the following: a user permanent identity (e.g., subscription permanent identifier (subscription permanent identifier, SUPI)), a globally unique temporary identity (globally unique temporary identifier, GUTI), a private identity, an N3 tunnel identity (N3 tunnel ID) (or UPF N3 tunnel ID).

Wherein the dedicated identification may represent an identification for use in case of a communication interface connection failure. The specific form of the dedicated identifier is not limited. For example, the private identification may be represented numerically; as another example, the unique identifier may be represented by letters (e.g., english letters).

It will be appreciated that the present application is primarily exemplified by a UE ID as any of the above. For example, the present application is not limited thereto, and any ID that can identify a UE is applicable to the present application. As another example, the UE ID may also include a plurality of UE IDs, for example, the UE ID may include SUPI and a dedicated identifier, etc., without limitation.

Optionally, the first communication device 420 comprises a source access network device (e.g. a source RAN), the communication system 400 further comprises a target access network device, and the first control plane device 410 is further configured to switch the terminal device from the source access network device to the target access network device in case of a communication interface connection failure between the first network and the second network. Thus, in a network handover scenario, i.e. a scenario in which a terminal device is handed over from a source access network device to a target access network device, the first control plane device 410 may replace the second control plane device to regulate the flow of the terminal device handed over from the source access network device to the target access network device. The handover may mean that the terminal device is handed over from the source access network device to the target access network device, where "handover" may be replaced by "mobile", "cell reselection" or "cell selection" in the description. As will be described in detail later with reference to fig. 7 to 10.

Optionally, in case of a failure recovery of the communication interface connection between the first network and the second network, the first control plane device 410 is further configured to trigger a path switching procedure for the terminal device, so that the terminal device is connected to the second control plane device. As will be described in detail later with reference to fig. 11.

Assuming that the first network is a PNI-NPN and the second network is a central network PLMN of the PNI-NPN, fig. 5 shows a schematic diagram of a network architecture provided according to an embodiment of the present application. As shown in fig. 5, the communication system deployed in PNI-NPN includes: a first control plane device L-CP, and a first communication device UPF and RAN. The L-CP may include L-AMF and L-SMF, among others. The following description is made in connection with two cases.

In case 1, the N2 interface and the N4 interface do not fail.

When the N2 interface and the N4 interface are not malfunctioning, the L-CP may act as a proxy node between the PNI-NPN device and the PLMN device, the proxy transmitting signaling between the PNI-NPN device and the PLMN device.

As shown in fig. 5, for the N2 interface, the L-CP may be considered as one AMF for the RAN, and the L-CP may be considered as one RAN for the AMF. For example, the RAN sending information to the AMF may include: the RAN firstly transmits the information to the L-CP, and then the L-CP forwards the information to the AMF; the AMF sends information to the RAN, which may include: the AMF sends the information to the L-CP first, which then forwards the information to the RAN.

As shown in fig. 5, for the N4 interface, the L-CP may be considered a SMF for the UPF, and the L-CP may be considered a UPF for the SMF. For example, the UPF sending information to the SMF may include: the UPF firstly transmits the information to the L-CP, and then the L-CP forwards the information to the SMF; the SMF sends information to the UPF, which may include: the SMF sends the information to the L-CP first, and then the L-CP forwards the information to the UPF.

For example, when the N2 interface and the N4 interface are not failed, the L-CP may also acquire a UE ID used on the N2 connection and a UE ID used on the N4 connection. For example, when the N2 connection is normal, the L-AMF in the L-CP acquires UE context information including a UE ID used on the N2 connection and saves the UE context information. For another example, when the N4 connection is normal, the L-SMF in the L-CP obtains UE context information and saves the UE context information, where the UE context information includes a UE ID used on the N4 connection.

Case 2, N2 interface and/or N4 interface fail.

When the N2 interface or the N4 interface fails, the L-CP executes part of the functions of the control surface to control the terminal equipment, thereby ensuring that the business of enterprises continues to normally run and meeting the requirement of PNI-NPN robustness. Wherein part of the functions of the control surface include, for example: the function of L-AMF, and/or the function of L-SMF. Regarding the functions of the L-AMF and the functions of the L-SMF, reference may be made to the functions of the foregoing AMF and SMF, and a detailed description thereof will not be given here.

As an example, when the N2 interface or the N4 interface fails, the L-CP may perform signaling interactions on the N2 interface or the N4 interface for the UE. For example, the L-CP performs signaling interactions on the N2 interface or the N4 interface for the UE according to the previously saved UE context information.

Through the network architecture provided in fig. 5, when a communication interface (such as an N2 interface and/or an N4 interface) between the PLMN and the PNI-NPN fails, the L-CP in the PNI-NPN performs part of the functions of the control plane to control the terminal device, so as to ensure that the enterprise service continues to be performed normally, and satisfy the requirement of the PNI-NPN network robustness.

The network architecture provided in the embodiments of the present application is described above in connection with fig. 4 and 5. Based on the network architecture in fig. 4 and fig. 5, the communication method provided in the embodiment of the present application is described below with reference to fig. 6 to fig. 11.

Fig. 6 is a schematic diagram of a communication method 600 according to an embodiment of the present application. The method 600 may be used for a first network as in fig. 4 or fig. 5. The method 600 may include the following steps.

601, in case that the second control plane device provides services for the terminal device, the first control plane device forwards control plane signaling of the terminal device transmitted between the first communication device and the second control plane device, where 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 a second network. Regarding the first control plane device, the second control plane device, and the first communication device, reference may be made to the foregoing description, and no further description is provided herein.

602, in the case that the second control plane device no longer provides services for the terminal device, transmitting control plane signaling of the terminal device between the first control plane device and the first communication device, and providing a control plane function for the terminal device by the first control plane device.

As an example, in case the second control plane device no longer provides services for the terminal device, the transmission of control plane signaling of the terminal device between the first control plane device and the first communication device may for example comprise: signaling over the N2 interface (e.g., signaling between RAN and AMF) and/or signaling over the N4 interface (e.g., signaling between SMF and UPF).

Based on the above scheme, when the second control plane device provides service for the terminal device, the first control plane device may serve as a proxy device (or referred to as a proxy node) between the first communication device and the second control plane device, and forward signaling between the first communication device and the second control plane device. The first control plane device may perform control plane functions to control the terminal device when the second control plane device is no longer providing services to the terminal device. Therefore, the network can provide service for the user, so that the stable operation of the user service can be ensured as much as possible, and the continuity of the user service is realized. 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 may act as a proxy device (or referred to as a proxy node) between the first communication device and the second control plane device, and forward 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 execute the control plane function to control the terminal device, so that the situation that the terminal device cannot be connected to the first network after the communication interface between the first network and the second network fails is avoided. Therefore, when the communication interface connection between the first network and the second network is normal, normal communication between the first communication equipment and the second control plane equipment is not affected, and when the communication interface connection between the first network and the second network is faulty, the service of the terminal equipment can be continuously and normally performed.

The second control plane device provides service for the terminal device, and the second control plane device no longer provides service for the terminal device, which means that in some cases, the second control plane device provides service for the terminal device, and in some cases, the second control plane device no longer provides service for the terminal device. Reference may be made specifically to the foregoing description, and details are not repeated here. Hereinafter, for convenience of understanding, the communication interface is mainly exemplified, and it will be understood that "the case where the communication interface is normally connected" may be replaced by "the case where the second control plane provides the service for the terminal device" and "the case where the communication interface is faulty" may be replaced by "the case where the second control plane no longer provides the service for the terminal device" hereinafter.

Optionally, the first control plane device acquires the UE ID in case the communication interface connection between the first network and the second network is normal. Thus, in case of a failure of the communication interface connection between the first network and the second network, the first control plane device may perform a signaling interaction on the communication interface for the terminal device based on the UE ID. Specifically, reference may be made to the foregoing description, and no further description is given here.

There are many ways for the first control plane device to acquire the UE ID, which is not limited.

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 setup request message to the first control plane device, the context setup request message carrying the UE ID. In another example, during PDU session establishment, the second control plane device sends a session establishment request message to the first control plane device, where the session establishment request message carries the UE ID. The manner in which the second control plane device determines the UE ID is described below in connection with fig. 7 to 10.

In a second possible way, the first control plane device receives the UE ID from the first communication device. For example, the UE ID is a UPF N3 tunnel ID, the first communication device includes a UPF, and if the UPF allocates the UPF N3 tunnel ID, the UPF sends the UPF N3 tunnel ID to the first control plane device. If in the PDU session establishment process, after receiving the session establishment request message from the second control plane device, the UPF sends a session establishment response message to the second control plane device through the first control plane device, where the session establishment response message carries the UPF N3 tunnel ID.

In a third possible way, the UE IDs are interacted between the first control plane devices. For example, the first control plane device includes an AMF and an SMF, and after the AMF acquires the UE ID, the AMF sends the UE ID to the SMF, and accordingly, the SMF receives the UE ID from the AMF. Further, when the communication interface connection fails, the SMF may identify a session context of the terminal device according to the UE ID. The AMF obtains the UE ID, which may include: the AMF identifies the context of the terminal device according to the control plane port identifier (such as the tunnel port identifier), and obtains the UE ID according to the context of the terminal device. The control plane port identifier is the port identifier of the control plane interface between the AMF and the access network equipment. The context information of the terminal equipment includes a UE ID, or the context information of the terminal equipment has an association relationship with the UE ID, and further the AMF may acquire the corresponding UE ID according to the context of the terminal equipment. It should be understood that the several possible ways described above are merely illustrative and the present application is not limited thereto.

Optionally, the method 600 further comprises: the first control plane device switches the terminal device from the source access network device to the target access network device. Thus, the first control plane device may replace the second control plane device, switching the terminal device from the source access network device to the target access network device. Based on the method provided in fig. 6, the flow of the first control plane device for switching the terminal device from the source access network device to the target access network device will be described in detail with reference to fig. 7 to 10.

Optionally, in case of a failure recovery of the communication interface connection between the first network and the second network, the first control plane device triggers a path switching procedure for the terminal device so that the terminal device is connected to the second control plane device. As will be described in detail later with reference to fig. 11.

For ease of understanding, a possible flow applicable to the embodiments of the present application is described below with reference to fig. 7 to 11, taking the communication interface as an example. As mentioned above, the UE ID may have different forms, and fig. 7 to 10 mainly describe possible flows of providing the control plane function for the terminal device by the first control plane device when the UE ID is in different forms; fig. 11 mainly illustrates a possible flow of the first control plane device triggering the path switching flow for the terminal device after the communication interface between the first network and the second network is failed to recover (i.e. the second control plane device provides services for the terminal device again). The method 700 shown in fig. 7 may be used in a scenario where the UE ID is SUPI, that is, when the communication interface between the first network and the second network fails in connection (i.e., the second control plane device no longer provides services for the terminal device), the first control plane device may perform signaling interaction on the communication interface for the terminal device based on the SUPI. The method 800 shown in fig. 8 may be used in a scenario where the UE ID is GUTI or S-TMSI, i.e. when the communication interface between the first network and the second network fails (i.e. the second control plane device no longer provides service to the terminal device), the first control plane device may perform signaling interaction on the communication interface for the terminal device based on GUTI or S-TMSI. The method 900 shown in fig. 9 may be used in a scenario where the UE ID is a dedicated identifier, i.e. when the communication interface between the first network and the second network fails (i.e. the second control plane device is no longer providing services to the terminal device), the first control plane device may perform signaling interaction on the communication interface for the terminal device based on the dedicated identifier. The method 1000 shown in fig. 10 may be used in a scenario where the UE ID is a UPF N3 tunnel ID, i.e. when the communication interface between the first network and the second network fails (i.e. the second control plane device is no longer providing service to the terminal device), the first control plane device may perform signaling interaction on the communication interface for the terminal device based on the UPF N3 tunnel ID. The method 1100 shown in fig. 11 may be used for the first control plane device to trigger a path switch procedure for the terminal device after the communication interface connection between the first network and the second network is failed, so that the terminal device is reconnected to the second control plane device.

Assume in the following example that the first control plane device L-CP includes L-SMF and L-AMF; a second control plane device deployed in a second network (e.g., PLMN) includes an SMF, referred to as PLMN-SMF, and an AMF, referred to as PLMN-AMF; the first communication device includes a UPF, an S-RAN, and a T-RAN; the terminal equipment is UE, the access network equipment of the UE before switching is S-RAN, and the access network equipment of the UE after switching is T-RAN.

Fig. 7 shows a schematic flow chart of a communication method 700 provided in an embodiment of the present application. The method 700 may include the following steps.

701, a communication connection is established between the l-CP and other devices.

The other devices include devices deployed in the first network, including S-RAN and UPF, for example, and devices deployed in the second network, which may include PLMN-SMF and PLMN-AMF, for example.

As an example, step 701 may include the following:

1) And 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.

The L-AMF establishes a node-level (or device-level) N2 signaling connection with the S-RAN in the role of AMF, including establishing a network protocol security (internet protocol address security, IPsec) security tunnel. 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 tunnel.

2) And a communication connection is established between the L-SMF and the UPF, and a communication connection is established between the L-SMF and the SMF.

The L-SMF establishes a node level (or device level) N4 signaling connection between the SMF's role and the UPF, including establishing an IPsec security tunnel. 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 security channel.

It will 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 one AMF, establishes a node level N2 signaling connection with the S-RAN. Other similarities, which are not described in detail herein.

The ue requests access to the network 702.

The UE requests access to the network, and transmits a registration request or a Service Request (SR) to the network.

Taking the example that the UE sends a registration request to the network, one possible procedure includes: the UE sends a registration request to the S-RAN, and after the S-RAN receives the registration request from the UE, the S-RAN sends an initial UE message (initial UE message) to the L-AMF to trigger the L-AMF to initiate the establishment of the N2 signaling connection corresponding to the UE (for simplicity, the establishment of the per UE N2 signaling connection); the 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 the per UE N2 signaling connection and forwarding (or transparent) the registration request to the PLMN-AMF.

Wherein, the establishment of the per UE N2 signaling connection initiated by the L-AMF may include, for example: establishment of per UE N2 signaling connection between L-AMF and S-RAN, and establishment of per UE N2 signaling connection between L-AMF and 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.

Wherein, PLMN-AMF initiates the establishment of per UE N2 signaling connection, which may include: establishment of per UE N2 signaling connection between PLMN-AMF and S-RAN, and establishment of per UE N2 signaling connection between PLMN-AMF and L-AMF. One possible procedure, the PLMN-AMF sends an initial context setup request (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. Accordingly, the S-RAN returns an initial context setup response (initial context setup response) message to the L-AMF, which then forwards the initial context setup response message to the PLMN-AMF.

And 703, performing security authentication and key negotiation between the PLMN-AMF and the UE.

And if the PLMN-AMF does not store the security context information of the UE, or the UE and the network do not carry out security authentication and key negotiation, the PLMN-AMF and the UE execute security authentication and key negotiation flow.

The specific procedure for performing security authentication and key agreement between PLMN-AMF and UE may refer to the description in the prior art, and is not limited.

The plmn-AMF determines 704 the SUPI as the UE ID.

UE ID for L-CP may identify and manage (or handle) the UE based on the UE ID in case of a connection failure of a communication interface (N2 interface and/or N4 interface) between the first network and the second network.

One possible way, after successfully authenticating the UE securely, the PLMN-AMF may determine whether the slice corresponding to the network slice selection assistance information (network slice selection assistance information, nsai) of the UE is an enterprise slice or whether there is a robustness solution, or whether there is a robustness solution for the first network (i.e. private network). If the PLMN-AMF judges that the slice corresponding to NSSAI of the UE is an enterprise slice or the robustness requirement exists or the first network has the robustness requirement, the PLMN-AMF knows that the service under the fault needs to be considered for the UE to normally operate, and the PLMN-AMF determines SUPI as the UE ID.

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 carries the SUPI.

705, the plmn-AMF returns registration accept information or service accept information to the UE.

Taking PLMN-AMF to return registration accept information to UE as an example, in a possible manner, the initial context setup request message sent by PLMN-AMF to L-AMF carries the registration accept information, and the initial context setup request message sent by L-AMF to S-RAN carries the registration accept information, and S-RAN sends the registration accept information to UE through RRC message.

Optionally, the initial context setup request message sent by the PLMN-AMF to the L-AMF and the initial context setup request message sent by the L-AMF to the S-RAN include information for establishing a UE context (UE context). The L-AMF and S-RAN may create the RAN UE context from the initial context setup request message, respectively.

The information for establishing the UE context may include, but is not limited to, one or more of the following: UE aggregate maximum bit rate (aggregate maximum bit rate), UE security capability (security capability), security keys (security keys), UE radio capability (radio capability), allowed network slice selection assistance information (allowed nsai), mobility restriction list (mobility restriction list), frequency selection priority (frequency selection priority, RFSP), RRC inactivity assistance information (RRC-inactive assistance information).

The l-AMF saves 706 the created RAN UE context.

The RAN UE context has an association (or correspondence) with SUPI. The RAN UE context has an association with SUPI, one possible form is: the RAN UE context includes SUPI; another possible form is: the RAN UE context associates the SUPI. It should be understood that the present application is not limited as to the specific form of association, as long as the SUPI associated with the RAN UE context can be known from the RAN UE context; or, according to SUPI, acquiring the RAN UE context associated with the SUPI is applicable to the application.

707, the ue initiates a protocol data unit (protocol data unit, PDU) session establishment.

After the UE accesses the network, the PDU session is established, for example, the UE sends a PDU session establishment request message to the L-AMF, which forwards the PDU session establishment request message to the PLMN-AMF. The UE may access an application server in the DN network through the established PDU session. It can be appreciated that after the PDU session is established, that is, the data transmission channels of the UE and DN are established.

708, the PLMN-AMF sends a PDU session establishment request message to the PLMN-SMF.

After receiving the PDU session establishment request message from the UE, the PLMN-AMF may select an appropriate PLMN-SMF for the UE and send the PDU session establishment request message to the PLMN-SMF.

709, the plmn-SMF sends an N4 session setup request message to the UPF.

After receiving the PDU session establishment request message of the UE sent by the PLMN-AMF, the PLMN-SMF sends an N4 session establishment request message to the UPF, wherein the N4 session establishment request message carries SUPI. For example, the PLMN-SMF sends an N4 session setup request message to the L-SMF, which forwards the N4 session setup request message to the UPF.

The upf sends an N4 session setup response message to the PLMN-SMF 710.

After receiving the N4 session establishment request message from the PLMN-SMF, the UPF sends an N4 session establishment response message to the PLMN-SMF. For example, the UPF sends an N4 session setup response message to the L-SMF, which forwards the N4 session setup response message to the PLMN-SMF.

Wherein, after receiving the N4 session establishment response message, the L-SMF saves the session management (session management, SM) context information of the UE. The SM context information of the UE has an association relationship (or correspondence relationship) with the SUPI, e.g., the SM context information of the UE includes the SUPI; or SM context information of the UE associates SUPI.

After receiving the N4 session establishment response message, the PLMN-SMF continues to execute the PDU session establishment procedure, which may include: the PLMN-SMF sends PDU session resource establishment request message to the S-RAN and PDU session establishment acceptance message to the UE. Wherein the PDU session resource establishment request message is operable to establish an N3 interface data transmission channel and an air interface data radio bearer (data radio bearer, DRB (s)) for the PDU session.

The steps 701 to 710 are possible flows before the N2 interface and/or the N4 interface fail. Possible flows after the N2 interface and/or the N4 interface fail are described below in connection with steps 711 to 718.

711 When the N2 interface and/or the N4 interface are/is in fault, the L-CP provides a control surface function for the UE.

For example, when the N2 interface fails, the L-AMF performs proxy N2 interface functions instead of PLMN-AMF to regulate the UE.

For another example, when the N4 interface fails, the L-SMF performs proxy N4 interface functions instead of PLMN-SMF to regulate the UE.

For another example, when both the N2 interface and the N4 interface fail, the L-AMF performs the proxy N2 interface function, the L-SMF performs the proxy N4 interface function, and the L-AMF and the L-SMF replace PLMN-AMF and PLMN-SMF respectively to regulate the UE.

In the following, a network switching scenario is mainly taken as an example, namely, the UE is switched from the S-RAN to the T-RAN, and the flow of controlling the UE by using the L-AMF and the L-SMF instead of the PLMN-AMF and the PLMN-SMF, respectively, is introduced.

712, the t-RAN sends a path switch (path switch) request message to the L-AMF.

One possible way is for the T-RAN to initiate a path switch for the UE, i.e. the T-RAN sends a path switch request message to the L-AMF.

It should be appreciated that prior to step 712, the method 700 may also include handover preparation between S-RAN, T-RAN, UE, and the present application is not limited.

713, the l-AMF identifies the RANUE context and obtains the SUPI associated with the RANUE context.

After the L-AMF receives the path switch request message from the T-RAN, the L-AMF may identify the RANUE context based on the AMF NG-AP tunnel port identification (tunnel endpoint identifier, TEID). The L-AMF may obtain the SUPI associated with the RAN UE context (or the SUPI corresponding to the RAN UE context) according to the RAN UE context.

In one possible scenario, the RAN UE context includes SUPI in step 706. In this case, the SUPI associated with the RAN UE context is acquired, which may be understood as acquiring the SUPI included in the RAN UE context.

In yet another possible scenario, in step 706, the RAN UE context associates with SUPI. In this case, the SUPI associated with the RAN UE context is acquired, which may be understood as acquiring the SUPI associated with the RAN UE context.

714, the L-AMF sends a PDU session management context update request (Nsmf_PDUSion_ UpdateSMContext Request) message to the L-SMF.

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

It should be appreciated that the PDU session management context update request message is only one possible way, and the names of its messages are not limited. Any message that can implement this message function is suitable for use in the embodiments of the present application.

715, the L-SMF obtains the SM context associated with the SUPI according to the SUPI.

The L-SMF obtains the SM context associated with the SUPI according to the SUPI so as to send N3AN tunnel info distributed by the T-RAN for the UE to the UPF.

In a possible case, in step 710, the SM context information of the UE includes SUPI. In this case, the SM context information associated with the SUPI is acquired, which may be understood as acquiring SM context information including the SUPI.

In yet another possible scenario, in step 710, the SM context information of the UE associates with SUPI. In this case, the SM context information associated with the SUPI is acquired, which may be understood as acquiring the SM context information associated with the SUPI.

716, an N4session modification (N4 session modification) procedure is performed between the l-SMF and the UPF.

For example, the L-SMF sends AN N4session modification request (N4 session modification request) message to the UPF using the per UE N4 signaling connection previously established with the UPF, the N4session modification request message carrying N3AN tunnel info allocated by the T-RAN for the UE. Accordingly, the UPF can send an N4session modification response (N4 session modification response) message to the L-SMF.

717, the L-SMF sends a PDU session management context update response (Nsmf_PDUSation_ UpdateSMContext Response) message to the L-AMF.

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

It should be appreciated that PDU session management context update response messages are only one possible way, and the names of their messages are not limited. Any message that can implement this message function is suitable for use in the embodiments of the present application.

718, the l-AMF returns a path update reply message to the T-RAN.

Considering that in the case of a communication interface failure, the L-AMF may not need to generate a new security parameter (such as an intermediate key NH) for the UE, and the path update response message may not carry the security parameter NH. The L-AMF can not generate new security parameters for the UE, so that the L-AMF can provide a control surface function for the terminal equipment when the communication interface between the first network and the second network fails, and the requirement on the L-AMF can be reduced, and the change on the existing protocol is small.

Based on the above scheme, when the communication interface between the first network and the second network is connected normally, the L-SMF and the L-AMF may act as proxy devices (or referred to as proxy nodes) between the first communication device and the second control plane device, and forward 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 L-SMF and the L-AMF can replace PLMN-SMF and PLMN-AMF to control the terminal equipment based on SUPI, so that the terminal equipment can not be connected to the first network any more after the communication interface between the first network and the second network fails. Therefore, when the communication interface connection between the first network and the second network is normal, normal communication between the first communication equipment and the second control plane equipment is not affected, and when the communication interface connection between the first network and the second network is faulty, the service of the terminal equipment can be continuously and normally performed.

Fig. 8 shows a schematic flow chart of a communication method 800 provided in an embodiment of the present application. The method 800 may include the following steps.

801, a communication connection is established between the l-CP and other devices.

802, the ue requests access to the network.

803, security authentication and key agreement is performed between the plmn-AMF and the UE.

Steps 801 to 803 are similar to steps 701 to 703, and will not be described here.

At 804, the PLMN-AMF determines the GUTI as the UE ID.

Alternatively, the PLMN-AMF determines a serving temporary Mobile subscriber identity (S-TMSI) as the UE ID. The method 800 is mainly described by way of example in terms of a GUTI, it being understood that the "GUTI" in the method 800 may also be replaced by "S-TMSI".

One possible way, after successfully authenticating the UE securely, the PLMN-AMF may determine whether the slice corresponding to the nsai of the UE is an enterprise slice or whether there is a robustness requirement, or whether there is a robustness requirement for the first network (i.e., private network). If the PLMN-AMF judges that the slice corresponding to NSSAI of the UE is an enterprise slice or the robustness requirement exists or the first network has the robustness requirement, the PLMN-AMF knows that the service under the fault needs to be considered for the UE to normally operate, and the PLMN-AMF determines the GUTI as the UE ID.

The PLMN-AMF may send the GUTI to the L-AMF via N2 signaling. For example, an initial context setup request message sent by the PLMN-AMF to the L-AMF carries the GUTI.

805, the plmn-AMF returns registration accept information or service accept information to the UE.

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

806, the l-AMF saves the created RAN UE context.

The RAN UE context has an association (or correspondence) with GUTI. The RAN UE context has an association with GUTI, one possible form is: the RAN UE context includes GUTI; another possible form is: the RAN UE context is associated with the GUTI. It should be understood that the present application is not limited as to the specific form of association, as long as the GUTI associated with the RAN UE context can be known from the RAN UE context; alternatively, according to the GUTI, the RAN UE context associated with the GUTI is known, which is suitable for the present application.

807, the ue initiates PDU session establishment.

Step 807 is similar to step 707 and is not described in detail herein.

808, the PLMN-AMF sends a PDU session establishment request message to the PLMN-SMF.

If the PLMN-AMF determines that the NSSAI or data network name (data network name, DNN) of the UE has the robustness requirement, or that the first network (i.e., private network) has the robustness requirement, the PLMN-AMF may send the GUTI to the selected PLMN-SMF. For example, the GUTI may be carried in a PDU session establishment request message.

809, the plmn-SMF sends an N4 session setup request message to the UPF.

After receiving a PDU (protocol data unit) session establishment request message of the UE sent by the PLMN-SMF, the PLMN-SMF sends an N4 session establishment request message to the UPF, wherein the N4 session establishment request message carries GUTI. For example, the PLMN-SMF sends an N4 session setup request message to the L-SMF, which forwards the N4 session setup request message to the UPF.

810, the upf sends an N4 session setup response message to the PLMN-SMF.

After receiving the response message of establishing the N4 session, the L-SMF saves SM context information of the UE. The SM context information of the UE has an association relationship (or a corresponding relationship) with the GUTI, for example, the SM context information of the UE comprises the GUTI; or the SM context information of the UE associates GUTI.

And after receiving the N4 session establishment response message, the PLMN-SMF continues to execute the PDU session establishment flow. Specifically, reference may be made to the description in step 710, and no further description is given here.

The steps 801 to 810 are possible flows before the N2 interface and/or the N4 interface fail. Possible flows after the N2 interface and/or the N4 interface fail are described below in connection with steps 811 to 818.

811 When the N2 interface and/or the N4 interface are/is in fault, the L-CP provides a control surface function for the UE.

The t-RAN sends 812 a path switch request message to the L-AMF.

Steps 811-812 are similar to steps 711-712 and are not described here.

813, the l-AMF identifies the RAN UE context and obtains the GUTI associated with the RAN UE context.

After the L-AMF receives the path switch request message from the T-RAN, the L-AMF may identify the RANUE context according to the AMF NG-AP TEID. The L-AMF may obtain, according to the RAN UE context, a GUTI associated with the RAN UE context (or a GUTI corresponding to the RAN UE context).

In one possible scenario, the RAN UE context includes GUTI in step 806. In this case, the GUTI associated with the RAN UE context is obtained, which is understood to be the GUTI included in the RAN UE context is obtained.

In yet another possible scenario, the RAN UE context has an association (or correspondence) with GUTI in step 806. In this case, the GUTI associated with the RAN UE context is obtained, which can be understood as the GUTI associated with the RAN UE context is obtained.

The L-AMF sends 814 a PDU session management context update request message to the L-SMF.

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

815, the L-SMF obtains the SM context associated with the GUTI according to the GUTI.

The L-SMF acquires the SM context associated with the GUTI according to the GUTI, so that N3 AN tunnel info distributed by the T-RAN for the UE is sent to the UPF.

In a possible scenario, in step 810, the SM context information for the UE includes GUTI. In this case, the SM context information associated with the GUTI is obtained, which may be understood as obtaining SM context information including the GUTI.

In yet another possible scenario, in step 810, the SM context information of the UE has an association (or correspondence) with the GUTI. In this case, the SM context information associated with the GUTI is acquired, which may be understood as acquiring the SM context information associated with the GUTI.

816, an N4 session modification procedure is performed between the l-SMF and the UPF.

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

818, the l-AMF returns a path update reply message to the T-RAN.

Steps 816-818 are similar to steps 716-718, and are not described in detail herein.

Based on the above scheme, when the communication interface between the first network and the second network is connected normally, the L-SMF and the L-AMF may act as proxy devices (or referred to as proxy nodes) between the first communication device and the second control plane device, and forward 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 L-SMF and the L-AMF can replace PLMN-SMF and PLMN-AMF to control the terminal equipment based on GUTI or S-TMSI, so that the terminal equipment can not be connected to the first network any more after the communication interface between the first network and the second network fails. Therefore, when the communication interface connection between the first network and the second network is normal, normal communication between the first communication equipment and the second control plane equipment is not affected, and when the communication interface connection between the first network and the second network is faulty, the service of the terminal equipment can be continuously and normally performed.

Fig. 9 shows a schematic flow chart of a communication method 900 provided in an embodiment of the present application. The method 900 may include the following steps.

901, a communication connection is established between the l-CP and other devices.

The ue requests access to the network 902.

903, security authentication and key agreement is performed between the plmn-AMF and the UE.

Steps 901-903 are similar to steps 701-703 and are not described here.

904, the plmn-AMF configures a dedicated identity for the UE.

I.e. the UE ID is a dedicated identity. The dedicated identity is used for identifying the UE and controlling (or handling) the UE based on the dedicated identity in case of a failure of a communication interface (N2 interface and/or N4 interface) connection between the first network and the second network. The specific form of the dedicated identifier is not limited. For example, the dedicated identity may be represented by an ID, e.g., different UEs correspond to different IDs; as another example, the unique identifier may be represented by letters (e.g., english letters).

One possible way, after successfully authenticating the UE securely, the PLMN-AMF may determine whether the slice corresponding to the nsai of the UE is an enterprise slice or whether there is a robustness requirement, or whether there is a robustness requirement for the first network (i.e., private network). If the PLMN-AMF determines that the slice corresponding to the nsai of the UE is an enterprise slice or the robustness requirement exists, or the first network has the robustness requirement, the PLMN-AMF knows that the service under the fault needs to be considered for the UE to operate normally, and the PLMN-AMF can configure (or generate) a dedicated identifier for the UE.

The PLMN-AMF may send the dedicated identity to the L-AMF via N2 signaling. For example, the PLMN-AMF includes the dedicated identity in an initial context setup request message sent to the L-AMF.

It should be understood that the method 900 is mainly illustrated by taking PLMN-AMF as an example for configuring a dedicated identifier for a UE, and the application is not limited thereto. For example, the specific identifier may be a specific identifier predefined by a protocol, or may be a specific identifier preconfigured by other network devices, or may be a specific identifier pre-stored in PLMN-AMF.

905, the plmn-AMF returns registration accept information or service accept information to the UE.

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

906, the l-AMF saves the RAN UE context.

The RAN UE context has an association (or correspondence) with a dedicated identity. The RAN UE context has an association with a dedicated identity, one possible form is: the RAN UE context includes a dedicated identity; another possible form is: the RAN UE context is associated with the dedicated identity. It should be understood that the present application is not limited in terms of the specific form of association, as long as the dedicated identity associated with the RAN UE context can be known from the RAN UE context; alternatively, the RAN UE context associated with the dedicated identifier is known according to the dedicated identifier, which is suitable for the present application.

907, ue initiates PDU session establishment.

Step 907 is similar to step 707 and will not be described again here.

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

If the PLMN-AMF determines that the NSSAI or DNN of the UE has the robustness requirement, or that the first network (i.e., private network) has the robustness requirement, the PLMN-AMF may send a dedicated identity to the selected PLMN-SMF. For example, the dedicated identification may be carried in a PDU session establishment request message.

909, the plmn-SMF sends an N4 session setup request message to the UPF.

After receiving the PDU session establishment request message of the UE sent by the PLMN-SMF, the PLMN-SMF sends an N4 session establishment request message to the UPF, wherein the N4 session establishment request message carries a special identifier. For example, the PLMN-SMF sends an N4 session setup request message to the L-SMF, which forwards the N4 session setup request message to the UPF.

The upf sends an N4 session setup response message to the PLMN-SMF 910.

After receiving the response message of establishing the N4 session, the L-SMF saves SM context information of the UE. The SM context information of the UE has an association relationship (or a corresponding relationship) with the special identifier, for example, the SM context information of the UE comprises the special identifier; or the SM context information of the UE associates a dedicated identity.

The steps 901 to 910 are possible flows before the N2 interface and/or the N4 interface fail. Possible flows after the N2 interface and/or the N4 interface fail are described below in connection with steps 911 through 918.

911 When the N2 interface and/or the N4 interface are/is in fault, the L-CP provides a control surface function for the UE.

The t-RAN sends a path switch request message to the L-AMF 912.

Steps 911-912 are similar to steps 711-712 and are not repeated here.

913, the l-AMF identifies the RAN UE context and obtains the dedicated identity associated with the RAN UE context.

After the L-AMF receives the path switch request message from the T-RAN, the L-AMF may identify the RANUE context according to the AMF NG-AP TEID. The L-AMF may obtain, according to the RAN UE context, a dedicated identifier associated with the RAN UE context (or referred to as a dedicated identifier corresponding to the RAN UE context).

In one possible scenario, the RAN UE context includes a dedicated identity in step 906. In this case, the private identity associated with the RAN UE context is acquired, which may be understood as acquiring the private identity included in the RAN UE context.

In yet another possible scenario, in step 906, the RAN UE context has an association (or correspondence) with a dedicated identity. In this case, the private identity associated with the RAN UE context is acquired, which may be understood as acquiring the private identity associated with the RAN UE context.

914, the L-AMF sends a PDU session management context update request message to the L-SMF.

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

915, the L-SMF obtains the SM context associated with the special identifier according to the special identifier.

The L-SMF obtains the SM context associated with the special identifier according to the special identifier so as to send N3 AN tunnel info distributed by the T-RAN for the UE to the UPF.

In a possible scenario, in step 810, the SM context information of the UE includes a dedicated identity. In this case, the SM context information associated with the dedicated identity is acquired, which may be understood as acquiring SM context information including the dedicated identity.

In yet another possible case, in step 810, the SM context information of the UE has an association (or correspondence) with the dedicated identity. In this case, the SM context information associated with the dedicated identity is acquired, which may be understood as acquiring the SM context information associated with the dedicated identity.

And 916, performing an N4 session modification procedure between the L-SMF and the UPF.

917, the L-SMF sends a PDU session management context update response message to the L-AMF.

918, the l-AMF returns a path update reply message to the T-RAN.

Steps 916-918 are similar to steps 716-718, and are not described herein.

Based on the above scheme, when the communication interface between the first network and the second network is connected normally, the L-SMF and the L-AMF may act as proxy devices (or referred to as proxy nodes) between the first communication device and the second control plane device, and forward 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 L-SMF and the L-AMF can replace PLMN-SMF and PLMN-AMF to control the terminal equipment based on the special identification, so that the terminal equipment can not be connected to the first network any more after the communication interface between the first network and the second network fails. Therefore, when the communication interface connection between the first network and the second network is normal, normal communication between the first communication equipment and the second control plane equipment is not affected, and when the communication interface connection between the first network and the second network is faulty, the service of the terminal equipment can be continuously and normally performed.

Fig. 10 shows a schematic flow chart of a communication method 1000 provided in an embodiment of the present application. The method 1000 may include the following steps.

1001, a communication connection is established between the l-CP and other devices.

At 1002, the ue requests access to the network.

And 1003, carrying out safety authentication and key negotiation between the PLMN-AMF and the UE.

Steps 1001-1003 are similar to steps 701-703, and will not be described here.

At 1004, the plmn-AMF returns registration accept information or service accept information to the UE.

Step 1004 is similar to step 705 and is not described in detail herein.

1005, the L-AMF saves the RAN UE context.

At 1006, the ue initiates PDU session establishment.

Step 1006 is similar to step 707 and is not described in detail herein.

1007, the PLMN-AMF sends a PDU session establishment request message to the PLMN-SMF.

At 1008, the plmn-SMF sends an N4 session setup request message to the UPF.

After receiving the PDU session establishment request message of the UE sent by the PLMN-SMF, the PLMN-SMF sends an N4 session establishment request message to the UPF. For example, the PLMN-SMF sends an N4 session setup request message to the L-SMF, which forwards the N4 session setup request message to the UPF.

1009, the upf sends an N4 session setup response message to the PLMN-SMF.

If, as a possible scenario, the PLMN-SMF allocates a UPF N3tunnel ID, the N4 session setup request message in step 1008 carries the UPF N3tunnel ID. For example, the PLMN-SMF sends an N4 session setup request message to the L-SMF, which forwards the N4 session setup request message to the UPF. After receiving the request message of establishing N4 session, L-SMF saves SM context information of UE. The SM context information of the UE has an association relationship (or a corresponding relationship) with the UPF N3tunnel ID, for example, the SM context information of the UE comprises the UPF N3tunnel ID; or the SM context information of the UE associates a UPF N3tunnel ID.

In another possible scenario, if the UPF assigns a UPF N3tunnel ID, then in step 1009, the UPF sends an N4 session setup response message to the PLMN-SMF carrying the UPF N3tunnel ID. For example, the UPF sends an N4 session setup response message to the L-SMF, which forwards the N4 session setup response message to the PLMN-SMF. After receiving the response message of establishing the N4 session, the L-SMF saves SM context information of the UE. The SM context information of the UE has an association relationship (or a corresponding relationship) with the UPF N3tunnel ID, for example, the SM context information of the UE comprises the UPF N3tunnel ID; or the SM context information of the UE associates a UPF N3tunnel ID.

In addition, after receiving the N4 session establishment response message, the PLMN-SMF continues to execute the PDU session establishment procedure, which may include: the PLMN-SMF sends PDU session resource establishment request to the S-RAN and PDU session establishment acceptance message to the UE. The PDU session resource establishment request includes a UPF N3 tunnel ID. The L-AMF acquires the UPF N3 tunnel ID from the PDU session resource establishment request message sent to the S-RAN by the PLMN-SMF, and performs association storage with the NG-AP AMF ID.

The steps 1001 to 1009 are possible flows before the N2 interface and/or the N4 interface fail. The following describes a possible flow after the N2 interface and/or the N4 interface fails in connection with steps 1010 to 1017.

1010 When the N2 interface and/or the N4 interface are/is in fault, the L-CP provides a control surface function for the UE.

1011, the t-RAN sends a path switch request message to the L-AMF.

Steps 1010-1011 are similar to steps 711-712 and are not described here.

1012, the l-AMF identifies the RAN UE context and obtains the UPF N3 tunnel ID associated with the RAN UE context.

After the L-AMF receives the path switch request message from the T-RAN, the L-AMF may identify the RAN UE context according to the AMF NG-AP TEID. The L-AMF may obtain the UPF N3 tunnel ID associated with the RAN UE context according to the RAN UE context.

1013, the L-AMF sends a PDU session management context update request message to the L-SMF.

1014, the L-SMF obtains the SM context associated with the UPF N3 tunnel ID according to the UPF N3 tunnel ID.

The L-SMF acquires the SM context associated with the UPF N3 tunnel ID according to the UPF N3 tunnel ID so as to send N3 AN tunnel info distributed by the T-RAN for the UE to the UPF.

In a possible case, in step 1009, the SM context information of the UE includes a UPF N3 tunnel ID. In this case, the SM context information associated with the UPF N3 tunnel ID is acquired, which may be understood as acquiring SM context information including the UPF N3 tunnel ID.

In yet another possible case, in step 1009, the SM context information of the UE has an association (or correspondence) with the UPF N3 tunnel ID. In this case, the SM context information associated with the UPF N3 tunnel ID is acquired, which can be understood as acquiring the SM context information associated with the UPF N3 tunnel ID.

1015, an N4 session modification procedure is performed between the l-SMF and the UPF.

1016, the L-SMF sends a PDU session management context update response message to the L-AMF.

1017, the l-AMF returns a path update reply message to the T-RAN.

Steps 1015-1017 are similar to steps 716-718 and are not described herein.

Based on the above scheme, when the communication interface between the first network and the second network is connected normally, the L-SMF and the L-AMF may act as proxy devices (or referred to as proxy nodes) between the first communication device and the second control plane device, and forward 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 L-SMF and the L-AMF can control the terminal equipment based on the UPF N3 tunnel ID instead of the PLMN-SMF and the PLMN-AMF, so that the terminal equipment can not be connected to the first network any more after the communication interface between the first network and the second network fails. Therefore, when the communication interface connection between the first network and the second network is normal, normal communication between the first communication equipment and the second control plane equipment is not affected, and when the communication interface connection between the first network and the second network is faulty, the service of the terminal equipment can be continuously and normally performed.

The above description mainly describes the flow of the L-SMF and L-AMF to control the terminal device instead of the PLMN-SMF and PLMN-AMF when the communication interface connection between the first network and the second network fails, with reference to fig. 7 to 10, and the following description describes the flow after the communication interface connection failure recovery with reference to fig. 11.

Fig. 11 shows a schematic flow chart diagram of a communication method 1100 provided by an embodiment of the present application. The method 1100 may include the following steps.

1101, the l-AMF detects a communication interface connection failure recovery.

If the L-AMF detects that the communication interface (N2 interface and/or N4 interface) connection fails to recover, the L-AMF triggers a path flow for the UE so that the UE can reappear to connect to the PLMN-AMF and/or the PLMN-SMF.

1102, the l-AMF sends a path switch request message to the PLMN-AMF.

1103, the PLMN-AMF sends a PDU session context update request message to the PLMN-SMF.

1104, an N4 session modification procedure is performed between the plmn-SMF and the L-SMF.

If the L-SMF knows that the N4 session modification procedure is the first N4 procedure after the failure recovery, the L-SMF does not send the N3 RAN tunnel ID to the UPF, i.e. the L-SMF does not execute the N4 session modification procedure with the UPF.

In another possible case, if the L-SMF knows that the N4 session modification procedure is the first N4 procedure after the failure recovery, the L-SMF and the UPF execute the N4 session modification procedure, and in the process that the L-SMF and the UPF execute the N4 session modification procedure, the N3 RAN tunnel ID is not sent to the UPF.

In another possible case, if the L-SMF knows that the N4 session modification procedure is the first N4 procedure after the failure recovery, the L-SMF and the UPF execute the N4 session modification procedure, and in the process that the L-SMF and the UPF execute the N4 session modification procedure, send the N3 RAN tunnel ID to the UPF, where the N3 RAN tunnel ID is the previous N3 RAN tunnel ID.

In either case, the UPF will still use the original N3 RAN tunnel ID.

1105, the plmn-AMF returns a path switch reply message to the L-AMF.

If the PLMN-AMF identifies that the RAN with fault recovery belongs to a device in a non-public network and the path is switched to the first path switch after 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 with fault recovery belongs to a device in a non-public network, and the path is switched to the first path after fault recovery, the PLMN-AMF may not generate new security parameters for the UE, which not only saves resources, but also has little modification to the existing protocol.

1106, the L-CP stops controlling the UE.

That is, the L-AMF and the L-SMF do not perform control plane functions to control the terminal device in place of the PLMN-AMF and the PLMN-SMF.

1107, l-CP acts as a proxy node, forwarding signaling transmitted between RAN/UPF and PLMN-AMF and PLMN-SMF.

After the UE is reconnected to the PLMN-AMF and the PLMN-SMF, the L-AMF forwards (or refers to as transit) signaling transmitted between the RAN and the PLMN-AMF as a proxy node, and the L-SMF forwards (or refers to as transit) signaling transmitted between the UPF and the PLMN-SMF as a proxy node.

It is to be appreciated that method 1100 and methods 700-1000 can be used in combination. For example, prior to step 1101, the method 1100 may further include steps in methods 700-1000.

Based on the above scheme, after the communication interface connection between the first network and the second network is recovered, the L-AMF and the L-SMF may trigger a path switching procedure for the terminal device, so that the terminal device is reconnected to the PLMN-AMF and the PLMN-SMF. The L-AMF and L-SMF may act as proxy nodes forwarding signaling for transmissions between the RAN/UPF and the PLMN-AMF and PLMN-SMF. Therefore, when the communication interface between the first network and the second network is normally connected, normal communication between the first communication equipment and the second control plane equipment is not influenced, and normal transmission of the service of the terminal equipment is ensured.

It will be appreciated that the examples in fig. 7-11 in the embodiments of the present application are merely for convenience of understanding the embodiments of the present application by those skilled in the art, and are not intended to limit the embodiments of the present application to the specific scenarios illustrated. From the examples of fig. 7-11, it will be apparent to those skilled in the art that various equivalent modifications or variations may be made, and such modifications or variations are intended to be within the scope of the embodiments of the present application. For example, in fig. 7 to 11, "the case where the communication interface connection is normal" may be replaced with "the case where the second control plane provides service to the terminal device", and "the case where the communication interface connection fails" may be replaced with "the case where the second control plane no longer provides service to the terminal device".

It will also be appreciated that some optional features of the various embodiments of the application may, in some circumstances, be independent of other features, or may, in some circumstances, be combined with other features, without limitation.

It is also to be understood that the aspects of the embodiments of the present application may be used in any reasonable combination, and that the explanation or illustration of the terms presented in the embodiments may be referred to or explained in the various embodiments without limitation.

It should be further understood that the magnitude of the various numerical numbers in the embodiments of the present application do not imply any order of execution, but are merely convenient to distinguish between the embodiments, and should not be construed as limiting the implementation of the embodiments of the present application.

It will be further appreciated that in embodiments of the present application, some message names are referred to, such as path switch request messages or PDU session management context update request messages, etc., and that the naming thereof is not intended to limit the scope of the embodiments of the present application.

It will also be appreciated that in some of the above embodiments, the communication interface is mainly exemplified, and the present application is not limited thereto. The "normal connection condition of the communication interface" may be replaced by the "condition that the second control plane provides service for the terminal device", and the "condition that the communication interface connection fails" may be replaced by the "condition that the second control plane no longer provides service for the terminal device".

It should also be understood that in some embodiments, the mobile management network element is mainly exemplified by the AMF, and the session management network element is exemplified by the SMF, which is not limited to this application, and any network element capable of implementing the AMF, or any network element capable of implementing the SMF, is suitable for the application.

It should also be understood that, in the foregoing embodiments of the methods and operations implemented by a device or a network element (e.g., a first control plane device, and also e.g., a second control plane device), the methods and operations may also be implemented by a component (e.g., a chip or a circuit) of the device or the network element.

Corresponding to the methods given by the above method embodiments, the embodiments of the present application also provide corresponding apparatuses, where the apparatuses include corresponding modules for performing the above method embodiments. The module may be software, hardware, or a combination of software and hardware. It will be appreciated that the technical features described in the method embodiments described above are equally applicable to the device embodiments described below.

Fig. 12 is a schematic block diagram of a communication device provided in an embodiment of the present application. The apparatus 1200 comprises a transceiver unit 1210, which transceiver unit 1210 may be adapted to implement corresponding communication functions. The transceiving unit 1210 may also be referred to as a communication interface or a communication unit.

Optionally, the apparatus 1200 may further include a processing unit 1220, where the processing unit 1220 may be configured to perform data processing.

Optionally, the apparatus 1200 further includes a storage unit, where the storage unit may be configured to store instructions and/or data, and the processing unit 1220 may read the instructions and/or data in the storage unit, so that the apparatus implements the actions of the network device (e.g., the control plane device, such as the mobility management network element, such as the session management network element) in the foregoing method embodiments.

The apparatus 1200 may be configured to perform the actions performed by the network device (e.g., the first control plane device, and also e.g., the second control plane device) in the above method embodiments, where the apparatus 1200 may be the network device or a component of the network device, the transceiver unit 1210 is configured to perform the operations related to the transceiver on the network device side in the above method embodiments, and the processing unit 1220 is configured to perform the operations related to the processing on the network device side in the above method embodiments.

As a design, the apparatus 1200 is configured to perform the actions performed by the first control plane device in the above method embodiments.

In one possible implementation manner, the apparatus 1200 is disposed in a first network, where the second control plane device provides services for the terminal device, and the transceiver 1210 is configured to forward control plane signaling of the terminal device transmitted between the first communication device disposed in the first network and the second control plane device disposed in the second network, where the second control plane device is configured to provide a control plane function for the terminal device, and the second control plane device is a device disposed in the second network; in case the second control plane device no longer serves the terminal device, the transceiver unit 1210 is configured to transmit control plane signaling with the first communication device, and the apparatus 1200 is configured to provide control plane functions for the terminal device.

In some possible embodiments, in case the second control plane device provides services for the terminal device, the transceiver unit 1210 is further configured to obtain the association identifier of the terminal device.

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 a terminal device from the second control plane device.

Illustratively, in the case that the second control plane device provides services for the terminal device, the transceiver unit 1210 is further configured to receive a first message from the second control plane device; the processing unit 1220 is configured to store context information of the terminal device according to the first message, where the context information of the terminal device has an association relationship with an association identifier of the terminal device.

In some possible embodiments, in a case where the second control plane device no longer provides services for the terminal device, the transceiver unit 1210 is further configured to obtain the context information of the terminal device through the association identifier of the terminal device.

Optionally, the association identifier of the terminal device is any one of the following: user permanent identity, globally unique temporary identity, private identity, N3 tunnel identity.

In some possible embodiments, the first communication device comprises a source access network device, the first network further comprises a target access network device, and the processing unit 1220 is configured to switch the terminal device from the source access network device to the target access network device in case the second control plane device no longer provides services for the terminal device.

Illustratively, the first communication device further includes a user plane function network element, and the transceiver unit 1210 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 transceiver unit 1210 is further configured to obtain an association identifier of the terminal device; the transceiver unit 1210 is configured to send N3 tunnel information to a user plane function network element based on an association identifier of the terminal device.

In some possible embodiments, if the second control plane device does not provide service to the terminal device any more, the processing unit 1220 is further configured to trigger the path switching procedure for the terminal device, so that the terminal device is connected to the second control plane device, if the second control plane device provides service to the terminal device again.

Optionally, the first control surface device includes: the first mobility management network element and/or the first session management network element.

Optionally, the first network is a local network of the public network integrated non-public network, and the second network is a central network of the public network integrated non-public network.

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

The apparatus 1200 may implement steps or processes corresponding to those performed by the first control plane device in the method embodiment according to the embodiment of the present application, and the apparatus 1200 may include a unit for performing the method performed by the first control plane device in the embodiment shown in fig. 6, or include a unit for performing the method performed by the L-AMF and the L-SMF in any one of the embodiments shown in fig. 7 to 11.

As another design, the apparatus 1200 is configured to perform the actions performed by the first mobility management network element (e.g., L-AMF) in the above method embodiments.

A possible implementation manner, the transceiver unit 1210 is configured to obtain an association identifier of the terminal device, where 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 1210 is further configured to send an association identifier of the terminal device to the first session management network element; wherein the apparatus 1200 and the first session management network element are deployed in a first network.

In some possible embodiments, in case 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, where the second mobility management network element is deployed in the second network.

Illustratively, in the case that the second control plane device provides services for the terminal device, the transceiver unit 1210 is further configured to receive a first message from the second mobility management network element; a processing unit 1220, configured to save context information of the terminal device according to the first message, where the context information of the terminal device has an association relationship with an association identifier of the terminal device.

In some possible embodiments, in a case that the second control plane device no longer provides services for the terminal device, the processing unit 1220 is configured to identify a context of the terminal device according to a control plane port identifier, where the control plane port identifier is a port identifier of a control plane interface between the first mobility management network element and the access network device; and acquiring the association identifier of the terminal equipment according to the context of the terminal equipment.

In some possible embodiments, if the second control plane device does not provide services for the terminal device any more, the processing unit 1220 is configured to trigger a path switching procedure 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, where the second session management network element and the second mobility management network element are deployed in the second network.

The apparatus 1200 may implement steps or procedures performed corresponding to the first mobility management network element in the method embodiments according to the embodiments of the present application. Such as the elements of a method that the apparatus 1200 may perform with an L-AMF in any one of the embodiments shown in fig. 7-11.

As another design, the apparatus 1200 may be configured to perform the actions performed by the first session management network element (e.g., L-SMF) in the various method embodiments above.

A possible implementation manner, the transceiver unit 1210 is configured to receive an association identifier of a 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 the 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 processing unit 1220 is configured to identify, according to the association identifier of the terminal device, a session context associated with the association identifier of the terminal device; wherein the apparatus 1200 and the first mobility management element are deployed in a first network.

In some possible embodiments, in case 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.

In some possible embodiments, in case the second control plane device provides services for the terminal device, the transceiver unit 1210 is further configured 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; a processing unit 1220, configured to save context information of the terminal device according to the first message, where the context information of the terminal device has an association relationship with an association identifier of the terminal device.

In some possible embodiments, when the second control plane device no longer provides services for the terminal device, the transceiver 1210 is further configured to obtain 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.

The apparatus 1200 may implement steps or flows performed corresponding to the first session management network element in the method embodiments according to the embodiments of the present application. The apparatus 1200 includes means for performing the method of L-SMF in any of the embodiments shown in fig. 7-11.

As another design, the apparatus 1200 is configured to perform the actions performed by the second mobility management network element (e.g., PLMN-AMF) in the above method embodiments.

A possible implementation manner, the processing unit 1220 is configured to determine, by using the second mobility management network element, an association identifier of the terminal device, where 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; a transceiver unit 1210, configured to send an association identifier of the terminal device to the first mobility management network element; wherein the first mobility management element is deployed in a first network and the apparatus 1200 is deployed in a second network.

Illustratively, the processing unit 1220 is configured to determine an association identifier of the terminal device, including: if the network slice supported by the terminal device and/or the first network has a robustness requirement, the processing unit 1220 is configured to determine the association identifier of the terminal device.

In some possible embodiments, the transceiver unit 1210 is further configured to send 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.

Optionally, the association identifier of the terminal device is any one of the following: user permanent identification, globally unique temporary identification, private identification.

The apparatus 1200 may implement steps or procedures performed corresponding to the second mobility management network element in the method embodiment according to the embodiment of the present application. The apparatus 1200 comprises means for performing the method of PLMN-AMF in any one of the embodiments shown in fig. 7 to 11.

As another design, the apparatus 1200 is configured to perform the actions performed by the second session management network element (e.g., PLMN-SMF) in the method embodiments above.

A possible implementation manner, the transceiver unit 1210 is configured to obtain an association identifier of the terminal device, where 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 1210 is further configured to send an association identifier of the terminal device to the first session management network element; wherein the first session management network element is deployed in a first network and the apparatus 1200 is deployed in a second network.

In some possible embodiments, if a network slice supported by the terminal device or the first network has a robustness requirement, the transceiver unit 1210 is further configured to send the association identifier of the terminal device to the user plane function network element, where the user plane function network element is deployed in the first network.

Illustratively, a processing unit 1220 is configured to determine an association identifier of the 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.

The apparatus 1200 may implement steps or procedures performed corresponding to the second session management network element in the method embodiment according to the embodiment of the present application. The apparatus 1200 comprises means for performing the method of PLMN-SMF in any of the embodiments shown in fig. 7 to 11.

It should be understood that the specific process of each unit performing the corresponding steps has been described in detail in the above method embodiments, and is not described herein for brevity.

It should also be appreciated that the apparatus 1200 herein is embodied in the form of functional units. The term "unit" herein may refer to an application specific integrated circuit (application specific integrated circuit, ASIC), an electronic circuit, a processor (e.g., a shared, dedicated, or group processor, etc.) and memory that execute one or more software or firmware programs, a combinational logic circuit, and/or other suitable components that support the described functionality. In an alternative example, it will be understood by those skilled in the art that the apparatus 1200 may be specifically configured as the network device (e.g., the first control plane device and the second control plane device) in the foregoing embodiment, and may be used to perform each flow and/or step corresponding to the network device (e.g., the first control plane device and the second control plane device) in the foregoing method embodiments, which is not described herein for avoiding repetition.

The apparatus 1200 of each of the above aspects has a function of implementing the corresponding steps performed by the network device (e.g., the first control plane device, and also e.g., the second control plane device) in the above method. The functions may be implemented by hardware, or may be implemented by hardware executing corresponding software. The hardware or software comprises one or more modules corresponding to the functions; for example, the transceiver unit may be replaced by a transceiver (e.g., a transmitting unit in the transceiver unit may be replaced by a transmitter, a receiving unit in the transceiver unit may be replaced by a receiver), and other units, such as a processing unit, etc., may be replaced by a processor, to perform the transceiver operations and related processing operations in the various method embodiments, respectively.

The transceiver 1210 may be a transceiver circuit (e.g., may include a receiving circuit and a transmitting circuit), and the processing unit may be a processing circuit.

It should be noted that the apparatus in fig. 12 may be a network element or a device in the foregoing embodiment, or may be a chip or a chip system, for example: system on chip (SoC). The receiving and transmitting unit can be an input and output circuit and a communication interface; the processing unit is an integrated processor or microprocessor or integrated circuit on the chip. And are not limited herein.

As shown in fig. 13, another communication device 1300 is provided in an embodiment of the present application. The apparatus 1300 includes a processor 1310, the processor 1310 being coupled to a memory 1320, the memory 1320 being for storing computer programs or instructions and/or data, the processor 1310 being for executing the computer programs or instructions stored by the memory 1320 or for reading the data stored by the memory 1320 for performing the methods in the method embodiments above.

Optionally, the processor 1310 is one or more.

Optionally, the memory 1320 is one or more.

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

Optionally, as shown in fig. 13, the apparatus 1300 further comprises a transceiver 1330, the transceiver 1330 being for receiving and/or transmitting signals. For example, the processor 1310 is configured to control the transceiver 1330 to receive and/or transmit signals.

Alternatively, the apparatus 1300 is configured to implement the operations performed by a network device (e.g., a first control plane device, and a second control plane device) in the method embodiments above.

For example, the processor 1310 is configured to execute a computer program or instructions stored in the memory 1320 to implement the operations associated with the first control plane device in the method embodiments above. For example, the first control plane device in the embodiment shown in fig. 4 or fig. 5, or the method performed by the first control plane device in the embodiment shown in any one of fig. 6 to fig. 11.

It should be appreciated that the processors referred to in the embodiments of the present application may be central processing units (central processing unit, CPU), but may also be other general purpose processors, digital signal processors (digital signal processor, DSP), application specific integrated circuits (application specific integrated circuit, ASIC), off-the-shelf programmable gate arrays (field programmable gate array, FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, or the like. A general purpose processor may be a microprocessor or the processor may be any conventional processor or the like.

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

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

It should also be noted that the memory described herein is intended to comprise, without being limited to, these and any other suitable types of memory.

Referring to fig. 14, an embodiment of the present application provides a chip system 1400. The system-on-a-chip 1400 (or may also be referred to as a processing system) includes logic 1410 and an input/output interface 1420.

Logic 1410 may be a processing circuit in system on a chip 1400. Logic 1410 may be coupled to the memory unit and invoke instructions in the memory unit so that system-on-chip 1400 can implement the methods and functions of embodiments of the present application. The input/output interface 1420 may be an input/output circuit in the chip system 1400, and may output information processed by the chip system 1400, or input data or signaling information to be processed into the chip system 1400 for processing.

Alternatively, the system-on-chip 1400 is configured to implement the operations performed by the network device (e.g., the first control plane device, and the second control plane device) in the method embodiments described above.

For example, the logic 1410 is configured to implement the operations related to the processing performed by the first control plane device in the above method embodiment, such as the operations related to the processing performed by the first control plane device in the embodiment shown in any of fig. 6 to 11; the input/output interface 1420 is configured to implement the operations related to transmission and/or reception performed by the first control plane device in the above method embodiments, such as the operations related to transmission and/or reception performed by the first control plane device in any one of the embodiments shown in fig. 6 to 11.

Embodiments of the present application also provide a computer readable storage medium having stored thereon computer instructions for implementing the method performed by the network device (e.g., the first control plane device, and also e.g., the second control plane device) in the above method embodiments.

For example, the computer program, when executed by a computer, enables the computer to implement the method performed by the first control plane device in the above-described method embodiments.

Embodiments of the present application also provide a computer program product containing instructions that, when executed by a computer, implement a method performed by a network device (e.g., a first control plane device, and also e.g., a second control plane device) in the above method embodiments.

The explanation and beneficial effects of the related content in any of the above-mentioned devices can refer to the corresponding method embodiments provided above, and are not repeated here.

In the several embodiments provided in this application, it should be understood that the disclosed apparatus and method may be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative, e.g., the division of the units is merely a logical function division, and there may be additional divisions when actually implemented, e.g., multiple units or components may be combined or integrated into another system, or some features may be omitted or not performed. Furthermore, the coupling or direct coupling or communication connection shown or discussed with each other may be through some interface, device or unit indirect coupling or communication connection, which may be in electrical, mechanical or other form.

In the above embodiments, it may be implemented in whole or in part by software, hardware, firmware, or any combination thereof. When implemented in software, may 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 loaded and executed on a computer, produces a flow or function in accordance with embodiments of the present application, in whole or in part. The computer may be a general purpose computer, a special purpose computer, a computer network, or other programmable apparatus. For example, the computer may be a personal computer, a server, or a network device, etc. The computer instructions may be stored in or transmitted from one computer-readable storage medium to another, for example, by wired (e.g., coaxial cable, optical fiber, digital Subscriber Line (DSL)), or wireless (e.g., infrared, wireless, microwave, etc.). The computer readable storage medium may be any available medium that can be accessed by a computer or a data storage device such as a server, data center, etc. that contains an integration of one or more available media. For example, the aforementioned usable media include, but are not limited to, U disk, removable hard disk, read-only memory (ROM), random access memory (random access memory, RAM), magnetic disk or optical disk and other various media that can store program code.

The foregoing is merely specific embodiments of the present application, but the scope of the present application is not limited thereto, and any person skilled in the art can easily think about changes or substitutions within the technical scope of the present application, and the changes and substitutions are intended to be covered by the scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims

1. A communication system, wherein the communication system is deployed in a first network, the first network and a second network communicating via a communication interface;

the communication system includes: a first control plane device and a first communication device,

in case the second control plane device provides services for the 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, 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;

and under the condition that the second control plane device does not provide service for the terminal device any more, the first control plane device is used for transmitting control plane signaling with the first communication device, and the first control plane device is also used for providing control plane functions for the terminal device.

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

the first control plane device is configured to receive an association identifier of the terminal device from the second control plane device.

4. The communication system of claim 3, wherein, in the case where the second control plane device provides services to 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 configured to store context information of the terminal device according to the first message,

the context information of the terminal equipment and the association identifier of the terminal equipment have an association relationship.

5. The communication system according to claim 4, wherein in case the second control plane device no longer serves the terminal device, the method further comprises:

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. A communication system according to any of claims 2 to 5, characterized in that the association identity of the terminal device is any of the following:

user permanent identity, globally unique temporary identity, private identity, N3 tunnel identity.

7. The communication system according to any one of claims 1 to 6, wherein the first communication device comprises a source access network device, the communication system further comprising a target access network device, wherein, in case the second control plane device no longer serves the terminal device,

the first control plane device is further configured to switch the terminal device from the source access network device to the target access network device.

8. The communication system of claim 7, wherein the first communication device further comprises a user plane function network element, wherein the first control plane device is further configured to switch the terminal device from the source access network device to the target access network device, comprising:

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 used for acquiring the association identifier of the terminal device;

the first control plane device is configured 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 of claims 1 to 8, wherein in case the second control plane device is no longer serving the terminal device, if the second control plane device is again serving the terminal device,

the first control plane device is further configured to trigger a path switching procedure for the terminal device, so that the terminal device and the second control plane device establish communication connection.

10. The communication system according to any one of claims 1 to 9, wherein the first control plane device comprises: the first mobility management network element and/or the first session management network element.

11. The communication system according to any one of claims 1 to 10, characterized in that,

the first network is a local network of a public network integrated non-public network, and the second network is a central network of the public network integrated non-public network.

12. The communication system according to any one of claims 1 to 11, characterized in that,

The communication interface includes an N2 interface and/or an N4 interface.

13. A method of communication, the method comprising:

in the case that a second control plane device deployed in a second network provides services for a terminal device, forwarding, by a first control plane device deployed in a first network, 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 configured to provide a control plane function for the terminal device;

and under the condition that the second control plane equipment does not provide service for the terminal equipment any more, transmitting control plane signaling between the first control plane equipment and the first communication equipment, and providing control plane functions for the terminal equipment by the first control plane equipment.

14. The method according to claim 13, wherein in case the second control plane device provides services for the terminal device, the method further comprises:

and the first control plane device acquires the association identifier of the terminal device.

15. The method of claim 14, wherein the first control plane device obtaining the association identifier of the terminal device comprises:

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, wherein in case the second control plane device provides services for the terminal device, the method further comprises:

the first control plane device receives a first message from the second control plane device;

and the first control plane device stores the context information of the terminal device according to the first message, wherein the context information of the terminal device has an association relationship with the association identifier of the terminal device.

17. The method of claim 16, wherein in the event that the second control plane device no longer serves the terminal device, the method further comprises:

and the first control plane equipment acquires the context information of the terminal equipment through the association identifier of the terminal equipment.

18. The method according to any of claims 14 to 17, wherein the association identity of the terminal device is any of the following:

19. The method according to any of claims 13 to 18, wherein the first communication device comprises a source access network device, the first network further comprising a target access network device, the method further comprising, in case the second control plane device no longer serves the terminal device:

the first control plane device switches the terminal device from the source access network device to the target access network device.

20. The method of claim 19, wherein the first communication device further comprises a user plane function network element, wherein the first control plane device handing over the terminal device from the source access network device to the target access network device comprises:

the first control plane device receives a switching request message from the target access network device, wherein the switching request message comprises N3 tunnel information distributed by the target access network device for the terminal device;

the first control plane device acquires the association identifier of the terminal device;

and the first control plane device sends the N3 tunnel information to the user plane function network element based on the association identifier of the terminal device.

21. The method according to any one of claims 13 to 20, further comprising:

and under the condition that the second control plane equipment does not provide service for the terminal equipment any more, if the second control plane equipment provides service for the terminal equipment again, the first control plane equipment triggers a path switching flow for the terminal equipment so that the terminal equipment is connected to the second control plane equipment.

22. The method of any one of claims 13 to 21, wherein the first control surface device comprises: the first mobility management network element and/or the first session management network element.

23. The method according to any one of claims 13 to 22, wherein,

24. The method according to any one of claims 13 to 23, wherein,

the communication interface includes an N2 interface and/or an N4 interface.

25. A method of communication, the method comprising:

the method comprises the steps that a first mobile management network element obtains an association identifier of terminal equipment, wherein the association identifier of the terminal equipment is used for identifying the terminal equipment when second control plane equipment deployed in a second network does not provide service for the terminal equipment any more;

The first mobility management network element sends the association identifier of the terminal equipment 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.

26. The method of claim 25, wherein in the case where the second control plane device provides services to the terminal device, the method further comprises:

the first mobility management network element receives an association identifier of the terminal device from a second mobility management network element, the second mobility management network element being deployed in the second network.

27. The method of claim 26, wherein in the case where the second control plane device provides services to the terminal device, the method further comprises:

the first mobility management network element receives a first message from the second mobility management network element;

and the first mobility management network element stores the context information of the terminal equipment according to the first message, wherein the context information of the terminal equipment has an association relationship with the association identifier of the terminal equipment.

28. The method according to any of the claims 25 to 27, wherein the first mobility management element obtains an association identity of a terminal device, comprising:

The first mobility management network element identifies the context of the terminal device according to a control plane port identifier under the condition that the second control plane device no longer provides service for the terminal device, wherein the control plane port identifier is a port identifier of a control plane interface between the first mobility management network element and access network equipment;

and the first mobility management network element acquires the association identifier of the terminal equipment according to the context of the terminal equipment.

29. The method according to any one of claims 25 to 28, further comprising:

and if the second control plane device does not provide service for the terminal device any more, if the second control plane device provides service for the terminal device again, the first mobility management network element triggers a path switching procedure for the terminal device so that the terminal device establishes 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. A method of communication, the method comprising:

The method comprises the steps that a first session management network element receives an association identifier of terminal equipment from a first mobile management network element, wherein the association identifier of the terminal equipment is used for identifying the terminal equipment when second control plane equipment deployed in a second network is no longer used for providing services for the terminal equipment;

when the second control plane device no longer provides service for the terminal device, the first session management network element identifies a session context associated with the association identifier of the terminal device according to 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.

31. The method of claim 30, wherein in the case where the second control plane device provides services to the terminal device, the method further comprises:

the first session management network element receives an association identifier of the terminal device from a second session management network element, the second session management network element being deployed in the second network.

32. The method of claim 31, wherein in the case where the second control plane device provides services to the terminal device, the method further comprises:

The first session management network element receives a first message from a second session management network element, the second session management network element being deployed in the second network;

and the first session management network element stores the context information of the terminal equipment according to the first message, wherein the context information of the terminal equipment has an association relationship with the association identifier of the terminal equipment.

33. The method according to any of claims 30 to 32, wherein when the second control plane device is no longer serving the terminal device, the method further comprises:

and the first session management network element acquires the context information of the terminal equipment according to the association identifier of the terminal equipment and sends a session modification request message to the user plane function network element.

34. The method according to any of claims 25 to 33, wherein the association identity of the terminal device is any of the following:

35. A method of communication, the method comprising:

the second mobility management network element determines an association identifier of the terminal device, wherein the association identifier of the terminal device is used for identifying the terminal device when a second control plane device deployed in a second network no longer provides service for the terminal device;

The second mobility management network element sends the association identifier of the terminal equipment to the 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.

36. The method of claim 35, wherein the second mobility management element determining the association identifier of the terminal device comprises:

and if the network slice supported by the terminal equipment and/or the first network has robustness requirements, the second mobility management network element determines the association identifier of the terminal equipment.

37. The method according to claim 35 or 36, characterized in that the method further comprises:

and the second mobile management network element sends the association identifier of the terminal equipment to a second session management network element, wherein the second session management network element is deployed in the second network.

38. A method of communication, the method comprising:

the second session management network element obtains an association identifier of the terminal equipment, wherein the association identifier of the terminal equipment is used for identifying the terminal equipment when second control plane equipment deployed in a second network does not provide service for the terminal equipment any more;

The second session management network element sends the association identifier of the terminal device to the 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.

39. The method of claim 38, wherein the method further comprises:

and if the network slice supported by the terminal equipment or the first network has a robustness requirement, the second session management network element sends the association identifier of the terminal equipment to a user plane function network element, wherein the user plane function network element is deployed in the first network.

40. The method of claim 38 or 39, wherein,

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.

41. The method according to any of claims 35 to 40, wherein the association identity of the terminal device is any of the following:

user permanent identification, globally unique temporary identification, private identification.

42. A communication device, comprising:

a processor for executing a computer program stored in a memory to cause the apparatus to perform the method of any one of claims 13 to 24, or to cause the apparatus to perform the method of any one of claims 25 to 29, or to cause the apparatus to perform the method of any one of claims 30 to 34, or to cause the apparatus to perform the method of any one of claims 35 to 37, or to cause the apparatus to perform the method of any one of claims 38 to 41.

43. The apparatus of claim 42, further comprising the memory.

44. A computer readable storage medium, having stored thereon a computer program, which when run on a computer causes the computer to perform the method of any one of claims 13 to 24, or causes the computer to perform the method of any one of claims 25 to 29, or causes the computer to perform the method of any one of claims 30 to 34, or causes the computer to perform the method of any one of claims 35 to 37, or causes the computer to perform the method of any one of claims 38 to 41.

45. A computer program product comprising instructions for performing the method of any one of claims 13 to 24 or for performing the method of any one of claims 25 to 29 or for performing the method of any one of claims 30 to 34 or for performing the method of any one of claims 35 to 37 or for performing the method of any one of claims 38 to 41.

46. A communication system comprising one or more of the following:

a first control plane device for performing the method of any one of claims 13 to 24;

a second mobility management network element for performing the method of any one of claims 35 to 37; or alternatively, the process may be performed,

a second session management network element for performing the method of any of claims 38 to 41.

47. A communication system comprising one or more of the following:

a first mobility management network element for performing the method of any one of claims 25 to 29;

a first session management network element for performing the method of any of claims 30 to 34;