CN117676730A

CN117676730A - Session migration method and device

Info

Publication number: CN117676730A
Application number: CN202211031201.9A
Authority: CN
Inventors: 周军平; 席国宝
Original assignee: Huawei Technologies Co Ltd
Current assignee: Huawei Technologies Co Ltd
Priority date: 2022-08-26
Filing date: 2022-08-26
Publication date: 2024-03-08

Abstract

The embodiment of the application provides a session migration method and a communication device, wherein the method comprises the following steps: the session management network element sends an address and downlink tunnel information of a terminal device to a first user plane network element, the terminal device is served by a second user plane network element, the downlink tunnel information and the address are corresponding to a first session, and the first session is established for the terminal device by the second user plane network element; the session management network element sends uplink tunnel information corresponding to a second session to the access network device, the uplink tunnel information is used for establishing a transmission channel of the second session between the access network device and the first user plane network element, the second session is established for the terminal device by the first user plane network element, and the address and the downlink tunnel information are both corresponding to the second session. According to the method and the device, the first session of the second user plane network element can be migrated to the first user plane network element, so that service interruption of the terminal equipment is avoided.

Description

Session migration method and device

Technical Field

The embodiment of the application relates to the field of communication, and more particularly relates to a method and a device for session migration.

Background

In the fifth generation (5th generation,5G) communication system, before the terminal device performs service transmission, the terminal device first accesses the user plane function (user plane function, UPF) of the 5G core network through the access network device, and creates a session through the UPF, so that the terminal device can perform service transmission through the created session. In the process of carrying out service transmission by the terminal equipment, if the UPF connected with the terminal equipment cannot continue to provide service for the terminal equipment, for example, the UPF fails, or the UPF needs to be upgraded, the session of the terminal equipment is disconnected from the UPF, so that the service transmission of the terminal equipment is interrupted.

Disclosure of Invention

The embodiment of the application provides a session migration method and device, so as to avoid interruption of service transmission of terminal equipment.

In a first aspect, a method for session migration is provided, which may be performed by a session management network element, or may also be performed by a component (such as a chip or a circuit) of the session management network element, which is not limited to this, and for convenience of description, will be described below with reference to the embodiment performed by the session management network element.

The method comprises the following steps: the session management network element sends an address and downlink tunnel information of a terminal device to a first user plane network element, the terminal device is served by a second user plane network element, the downlink tunnel information and the address are corresponding to a first session, and the first session is established for the terminal device by the second user plane network element; the session management network element sends uplink tunnel information corresponding to a second session to the access network device, the uplink tunnel information is used for establishing a transmission channel of the second session between the access network device and the first user plane network element, the second session is established for the terminal device by the first user plane network element, and the downlink tunnel information and the address both correspond to the second session.

Based on the technical scheme, the session management network element sends the address of the terminal equipment and the downlink tunnel information of the first session to the first user plane network element, so that the first user plane network element can establish a second session for the terminal equipment according to the address and the downlink tunnel information, and the session management network element sends the uplink tunnel information of the second session to the access network equipment, so that the access network equipment can establish an uplink transmission channel of the second session between the access network equipment and the first user plane network element according to the uplink tunnel information, and the session of the terminal equipment is migrated from the second user plane network element to the first user plane network element. Because the first session and the second session correspond to the same address, the service transmitted by the terminal equipment based on the session will not be interrupted in the process of migrating the session of the terminal equipment from the second user plane network element to the first user plane network element.

In addition, even if the second user plane network element fails, based on the above technical solution, the terminal device does not need to be disconnected (i.e. release the session) and then be disconnected again (i.e. reestablish the session), so that the service transmitted by the terminal device can be prevented from being interrupted for a long time.

With reference to the first aspect, in certain implementations of the first aspect, the method further includes: the session management network element receives the uplink tunnel information from the first user plane network element.

With reference to the first aspect, in certain implementations of the first aspect, the method further includes: the session management network element receives first indication information from the second user plane network element or the first user plane network element, where the first indication information is used to indicate migration of at least one session of the second user plane network element, and the at least one session includes the first session.

Wherein the at least one session of the second user plane network element is a session established by the second user plane network element.

Based on the above technical solution, the session management network element may determine to migrate at least one session of the second user plane network element according to the first indication information.

With reference to the first aspect, in certain implementations of the first aspect, the first indication information includes at least one data network name (data network name, DNN), the at least one session corresponding to the at least one DNN.

Wherein, the at least one DNN included in the first indication information is used for the session management network element to determine at least one session corresponding to the at least one DNN. In other words, in case that the first indication information includes at least one DNN, the first indication information is used to indicate migration of at least one session corresponding to the at least one DNN. The at least one session corresponding to the at least one DNN includes all sessions corresponding to each DNN of the at least one DNN.

Based on the technical scheme, the first indication information comprises at least one DNN, so that the session corresponding to the appointed DNN can be migrated.

With reference to the first aspect, in certain implementations of the first aspect, the method further includes: the session management network element receives a first instruction from a user, the first instruction being for instructing migration of at least one session of a second user plane network element, the at least one session comprising the first session.

Based on the above technical solution, the session management network element may determine to migrate at least one session of the second user plane network element according to the received first instruction.

With reference to the first aspect, in certain implementations of the first aspect, the first instruction includes at least one DNN, and the at least one session corresponds to the at least one DNN.

Wherein the first instruction includes at least one DNN for the session management network element to determine at least one session corresponding to the at least one DNN. In other words, in case the first instruction comprises at least one DNN, the first instruction is configured to instruct migration of at least one session corresponding to the at least one DNN.

Based on the technical scheme, the first instruction comprises at least one DNN, so that the migration of the session corresponding to the appointed DNN can be realized.

With reference to the first aspect, in certain implementations of the first aspect, the second user plane network element fails.

Based on the technical scheme, the session management network element can migrate the session of the second user plane network element under the condition of the second user plane network element fault, so that the service interruption caused by the second user plane network element fault can be avoided for a long time.

With reference to the first aspect, in certain implementations of the first aspect, the method further includes: the session management network element sends first notification information to the first user plane network element, wherein the first notification information is used for indicating that at least one session to be migrated of the second user plane network element has been migrated to the first user plane network element, and the at least one session to be migrated comprises the first session.

Based on the above technical solution, if the first user plane network element and the second user plane network element have a primary-backup relationship, the session management network element may send first notification information to the first user plane network element to indicate that the session to be migrated of the second user plane network element has been migrated to the first user plane network element, so that the first user plane network element may be upgraded from the backup user plane network element to the primary user plane network element according to the first notification information. After the first user plane network element is upgraded to the main user plane network element, the roundabout flow can be avoided, namely, the user plane data is directly transmitted between the terminal equipment and the data network through the first user plane network element without passing through the second user plane network element, and the short interruption of the service caused by the fact that the first user plane network element is upgraded to the main user plane network element after detecting the failure of the second user plane network element through the heartbeat information is avoided.

With reference to the first aspect, in certain implementations of the first aspect, the method further includes: the session management network element receives second notification information from the first user plane network element, where the second notification information is used to indicate that the first user plane network element has been upgraded from a standby user plane network element to a primary user plane network element.

Based on the technical scheme, after the first user plane network element is upgraded from the standby user plane network element to the active user plane network element, the second notification information is sent to the session management network element, so that the session management network element can determine that the first user plane network element is upgraded to the active user plane network element according to the second notification information.

With reference to the first aspect, in certain implementations of the first aspect, the method further includes: the session management network element sends second indication information to the second user plane network element, where the second indication information is used to indicate that the second user plane network element is degraded from the active user plane network element to the standby user plane network element.

Based on the above technical solution, if the first user plane network element and the second user plane network element have a primary-backup relationship, the session management network element may send second indication information to the second user plane network element to indicate that the second user plane network element is degraded to a backup user plane network element. If the second user plane network element is downgraded into the standby user plane network element, the first user plane network element is upgraded into the active user plane network element, so that the roundabout flow can be avoided, that is, the user plane data is directly transmitted between the terminal equipment and the data network through the first user plane network element without passing through the second user plane network element, and the short interruption of the service caused by the fact that the first user plane network element is upgraded into the active user plane network element after detecting the failure of the second user plane network element through the heartbeat information is avoided.

With reference to the first aspect, in certain implementations of the first aspect, the method further includes: the session management network element receives third notification information from the second user plane network element, where the third notification information is used to indicate that the second user plane network element has been degraded from the primary user plane network element to the standby user plane network element.

Based on the above technical solution, after the second user plane network element is downgraded from the active user plane network element to the standby user plane network element, the third notification information is sent to the session management network element, so that the session management network element can determine that the second user plane network element has been downgraded to the standby user plane network element according to the third notification information.

With reference to the first aspect, in certain implementations of the first aspect, the method further includes: the session management network element sends third indication information to the second user plane network element, where the third indication information is used to instruct the second user plane network element to delete the session context of the first session.

Based on the technical scheme, after the session management network element migrates the first session, third indication information is sent to the second user plane network element to indicate the second user plane network element to delete the session context of the first session, so that storage resources of the second user plane network element can be saved.

In a second aspect, a method for session migration is provided, which may be performed by the second user plane network element, or may also be performed by a component (such as a chip or a circuit) of the second user plane network element, which is not limited herein, and is described below by taking the second user plane network element as an example for convenience of description.

The method comprises the following steps: the second user plane network element receives a second instruction from the user; the second user plane network element sends first indication information to the session management network element according to the second instruction, wherein the first indication information is used for indicating migration of at least one session of the second user plane network element.

Based on the above technical solution, the second user plane network element may send the first indication information to the session management network element according to the received second instruction, so as to instruct the session management network element to migrate at least one session of the second user plane network element, thereby avoiding service interruption caused by that the second user plane network element cannot work normally. For example, before the second user plane network element upgrades or restarts, the second user plane network element receives the second instruction, and then the second user plane network element can send the first instruction information to the session management network element according to the received second instruction, so that service interruption caused by the upgrade or restart of the second user plane network element can be avoided.

With reference to the second aspect, in certain implementations of the second aspect, the second instruction includes at least one DNN, the first indication information includes at least one DNN, and the at least one session corresponds to the at least one DNN.

Based on the technical scheme, the second instruction and the first instruction information comprise at least one DNN, so that the session corresponding to the appointed DNN can be migrated.

With reference to the second aspect, in certain implementations of the second aspect, the method further includes: the second user plane network element receives third indication information from the session management network element, where the third indication information is used to instruct the second user plane network element to delete the at least one session.

Based on the above technical solution, the second user plane network element may delete the session context of at least one session according to the received third indication information, so that storage resources of the second user plane network element may be saved.

With reference to the second aspect, in certain implementations of the second aspect, the method further includes: the second user plane network element sends fourth indication information to the session management network element, where the fourth indication information is used to indicate that the at least one session is migrated from the first user plane network element to the second user plane network element.

Based on the above technical solution, after the second user plane network element resumes, for example, after the second user plane network element completes upgrading or completes restarting, fourth indication information may be sent to the session management network element, so as to instruct the session management network element to migrate at least one session to the second user plane network element.

With reference to the second aspect, in certain implementations of the second aspect, the method further includes: the second user plane network element issues (advertisement) second routing information, the second routing indicated by the second routing information has a higher priority than the first routing indicated by the first routing, the first routing corresponds to the second routing information issued by the first user plane network element, the first routing information and the second routing information correspond to a first address segment, and the first address segment includes an address corresponding to the at least one session.

Based on the above technical solution, after the second user plane network element issues the second routing information, the second user plane network element is upgraded to the active user plane network element, so that traffic roundabout can be avoided, that is, user plane data is directly transmitted between the terminal device and the data network through the second user plane network element without passing through the first user plane network element, and short interruption of service caused by the fact that the second user plane network element is upgraded to the active user plane network element after detecting the first user plane network element fault through the heartbeat information is avoided.

In a third aspect, a method for session migration is provided, where the method may be performed by the first user plane network element, or may also be performed by a component (such as a chip or a circuit) of the first user plane network element, and this is not limited to this, and for convenience of description, the following is described with reference to the embodiment performed by the first user plane network element.

The method comprises the steps that a first user plane network element receives first notification information from a session management network element, wherein the first notification information is used for indicating that at least one session to be migrated of a second user plane network element is migrated to the first user plane network element; the first user plane network element is updated to the main user plane network element from the standby user plane network element according to the first notification information.

Based on the above technical solution, the first user plane network element can be upgraded from the standby user plane network element to the active user plane network element according to the first notification information, so that traffic roundabout, that is, user plane data is directly transmitted between the terminal device and the data network through the first user plane network element without passing through the second user plane network element, and short service interruption caused by that the first user plane network element is upgraded to the active user plane network element after detecting the failure of the second user plane network element through the heartbeat information, can be avoided.

With reference to the third aspect, in certain implementations of the third aspect, the method further includes: the first user plane network element sends second notification information to the session management network element, wherein the second notification information is used for indicating that the first user plane network element is updated from a standby user plane network element to a main user plane network element.

With reference to the third aspect, in some implementations of the third aspect, upgrading the first user plane network element from a standby user plane network element to a primary user plane network element includes: the first user plane network element issues first routing information, the priority of a first routing indicated by the first routing information is higher than the priority of a second routing corresponding to second routing information issued by the second user plane network element, the first routing information and the second routing information correspond to a first address segment, and the address segment comprises an address corresponding to the at least one session.

With reference to the third aspect, in certain implementations of the third aspect, the method further includes: the first user plane network element receives second indication information from the session management network element, wherein the second indication information is used for indicating the first user plane network element to be degraded from the main user plane network element to the standby user plane network element; and degrading the first user plane network element into a standby user plane network element by the active user plane network element according to the second indication information.

Based on the above technical solution, if the session of the first user plane network element is migrated to another user plane network element, for example, to the second user plane network element, the first user plane network element may be degraded to a standby user plane network element according to the second indication information. If the first user plane network element is downgraded into a standby user plane network element, the second user plane network element is upgraded into a main user plane network element, so that the roundabout flow can be avoided, namely, the user plane data is directly transmitted between the terminal equipment and the data network through the second user plane network element without passing through the first user plane network element, and the short interruption of the service caused by the fact that the second user plane network element is upgraded into the main user plane network element after detecting the failure of the first user plane network element through the heartbeat information is avoided.

With reference to the third aspect, in certain implementations of the third aspect, the method further includes: the first user plane network element sends third notification information to the session management network element, where the third notification information is used to indicate that the first user plane network element has been degraded from the active user plane network element to the standby user plane network element.

Based on the technical scheme, after the first user plane network element is degraded from the main user plane network element to the standby user plane network element, third notification information is sent to the session management network element, so that the session management network element can determine that the first user plane network element is degraded to the standby user plane network element according to the third notification information.

In a fourth aspect, a communication device is provided, where the communication device includes a transceiver unit configured to send, to a first user plane network element, an address of a terminal device and downlink tunnel information, where the terminal device is served by a second user plane network element, where the downlink tunnel information and the address both correspond to a first session, where the first session is established by the second user plane network element for the terminal device; the transceiver unit is further configured to send uplink tunnel information corresponding to a second session to the access network device, where the uplink tunnel information is used to establish a transmission channel between the access network device and the first user plane network element for the second session, where the second session is established by the first user plane network element for the terminal device, and the downlink tunnel information and the address both correspond to the second session.

With reference to the fourth aspect, in some implementations of the fourth aspect, the transceiver unit is further configured to receive the uplink tunnel information from the first user plane network element.

With reference to the fourth aspect, in some implementations of the fourth aspect, the transceiver unit is further configured to receive first indication information from the second user plane network element or the first user plane network element, where the first indication information is used to indicate migration of at least one session of the second user plane network element, and the at least one session includes the first session.

With reference to the fourth aspect, in certain implementations of the fourth aspect, the first indication information includes at least one data network name DNN, and the at least one session corresponds to the at least one DNN.

With reference to the fourth aspect, in some implementations of the fourth aspect, the transceiver unit is further configured to receive a first instruction from a user, where the first instruction is configured to instruct migration of at least one session of the second user plane network element, where the at least one session includes the first session.

With reference to the fourth aspect, in certain implementations of the fourth aspect, the first instruction includes at least one DNN, and the at least one session corresponds to the at least one DNN.

With reference to the fourth aspect, in some implementations of the fourth aspect, the second user plane network element fails.

With reference to the fourth aspect, in some implementations of the fourth aspect, the transceiver unit is further configured to send first notification information to the first user plane network element, where the first notification information is used to indicate that at least one session to be migrated of the second user plane network element has been migrated to the first user plane network element, and the at least one session to be migrated includes the first session.

With reference to the fourth aspect, in some implementations of the fourth aspect, the transceiver unit is further configured to receive second notification information from the first user plane network element, where the second notification information is used to indicate that the first user plane network element has been upgraded from a standby user plane network element to a primary user plane network element.

With reference to the fourth aspect, in some implementations of the fourth aspect, the transceiver unit is further configured to send second indication information to the second user plane network element, where the second indication information is used to indicate that the second user plane network element is degraded from the active user plane network element to the standby user plane network element.

With reference to the fourth aspect, in some implementations of the fourth aspect, the transceiver unit is further configured to receive third notification information from the second user plane network element, where the third notification information is used to indicate that the second user plane network element has been downgraded from the active user plane network element to the standby user plane network element.

With reference to the fourth aspect, in some implementations of the fourth aspect, the transceiver unit is further configured to send third indication information to the second user plane network element, where the third indication information is used to instruct the second user plane network element to delete a session context of the first session.

In a fifth aspect, a communication device is provided, the communication device comprising a transceiver unit for receiving a second instruction from a user; the transceiver unit is further configured to send first indication information to a session management network element according to the second instruction, where the first indication information is used to indicate migration of at least one session of the second user plane network element.

With reference to the fifth aspect, in certain implementations of the fifth aspect, the second instruction includes at least one DNN, the first indication information includes at least one DNN, and the at least one session corresponds to the at least one DNN.

With reference to the fifth aspect, in some implementations of the fifth aspect, the transceiver unit is further configured to receive third indication information from the session management network element, where the third indication information is used to instruct the second user plane network element to delete the at least one session.

With reference to the fifth aspect, in some implementations of the fifth aspect, the transceiver unit is further configured to send fourth indication information to the session management network element, where the fourth indication information is used to indicate that the at least one session is migrated from the first user plane network element to the second user plane network element.

With reference to the fifth aspect, in some implementations of the fifth aspect, the transceiver unit is further configured to issue second routing information, where a priority of a second route indicated by the second routing information is higher than a priority of a first route, where the first route corresponds to the second routing information issued by the first user plane network element, and where the first routing information and the second routing information correspond to a first address segment, and where the first address segment includes an address corresponding to the at least one session.

In a sixth aspect, a communication device is provided, where the communication device includes a transceiver unit and a processing unit, where the transceiver unit is configured to receive first notification information from a session management network element, where the first notification information is configured to indicate that at least one session to be migrated of a second user plane network element has been migrated to the first user plane network element; the processing unit is used for upgrading the standby user plane network element into the active user plane network element according to the first notification information.

With reference to the sixth aspect, in some implementations of the sixth aspect, the transceiver unit is further configured to send second notification information to the session management network element, where the second notification information is used to indicate that the first user plane network element has been upgraded from a standby user plane network element to a primary user plane network element.

With reference to the sixth aspect, in some implementations of the sixth aspect, the transceiver unit is further configured to issue first routing information, where a priority of a first route indicated by the first routing information is higher than a priority of a second route, where the second route corresponds to second routing information issued by the second user plane network element, and the first routing information and the second routing information correspond to a first address segment, where the address segment includes an address corresponding to the at least one session.

With reference to the sixth aspect, in some implementations of the sixth aspect, the transceiver unit is further configured to receive second indication information from the session management network element, where the second indication information is used to indicate that the first user plane network element is downgraded from a primary user plane network element to a standby user plane network element; the processing unit is configured to downgrade from the active user plane network element to the standby user plane network element according to the second indication information.

With reference to the sixth aspect, in some implementations of the sixth aspect, the transceiver unit is further configured to send third notification information to the session management network element, where the third notification information is used to indicate that the first user plane network element has been downgraded from a primary user plane network element to a standby user plane network element.

In a seventh aspect, a communication device is provided that includes a processor. The processor is coupled to the memory and operable to execute instructions in the memory to implement the method of the first aspect and any one of the possible implementations of the first aspect. Optionally, the communication device further comprises a memory. Optionally, the communication device further comprises a communication interface, and the processor is coupled to the communication interface.

In one implementation, the communication device is a session management network element. When the communication device is a session management network element, the communication interface may be a transceiver, or an input/output interface.

In another implementation, the communication device is a chip configured in a session management network element. When the communication device is a chip configured in a session management network element, the communication interface may be an input/output interface.

Alternatively, the transceiver may be a transceiver circuit. Alternatively, the input/output interface may be an input/output circuit.

In an eighth aspect, a communications apparatus is provided that includes a processor. The processor is coupled to the memory and operable to execute instructions in the memory to implement the method of the second aspect and any one of the possible implementations of the second aspect. Optionally, the communication device further comprises a memory. Optionally, the communication device further comprises a communication interface, and the processor is coupled to the communication interface.

In one implementation, the communication device is a second user plane network element. When the communication device is a second user plane network element, the communication interface may be a transceiver, or an input/output interface.

In another implementation, the communication device is a chip configured in a second user plane network element. When the communication device is a chip configured in the second user plane network element, the communication interface may be an input/output interface.

In a ninth aspect, a communications apparatus is provided that includes a processor. The processor is coupled to the memory and operable to execute instructions in the memory to implement the method of any one of the possible implementations of the third aspect and the third aspect. Optionally, the communication device further comprises a memory. Optionally, the communication device further comprises a communication interface, and the processor is coupled to the communication interface.

In one implementation, the communication device is a first user plane network element. When the communication device is a first user plane network element, the communication interface may be a transceiver, or an input/output interface.

In another implementation, the communication device is a chip configured in the first user plane network element. When the communication device is a chip configured in the first user plane network element, the communication interface may be an input/output interface.

In a tenth aspect, there is provided a processor comprising: input circuit, output circuit and processing circuit. The processing circuit is configured to receive a signal via the input circuit and transmit a signal via the output circuit, such that the processor performs the method of any one of the possible implementations of the first to third aspects.

In a specific implementation process, the processor may be one or more chips, the input circuit may be an input pin, the output circuit may be an output pin, and the processing circuit may be a transistor, a gate circuit, a flip-flop, various logic circuits, and the like. The input signal received by the input circuit may be received and input by, for example and without limitation, a receiver, the output signal may be output by, for example and without limitation, a transmitter and transmitted by a transmitter, and the input circuit and the output circuit may be the same circuit, which functions as the input circuit and the output circuit, respectively, at different times. The embodiments of the present application do not limit the specific implementation manner of the processor and the various circuits.

In an eleventh aspect, a processing apparatus is provided that includes a processor and a memory. The processor is configured to read instructions stored in the memory and is configured to receive signals via the receiver and to transmit signals via the transmitter to perform the method of any one of the possible implementations of the first to third aspects.

Optionally, the processor is one or more, and the memory is one or more.

Alternatively, the memory may be integrated with the processor or the memory may be separate from the processor.

In a specific implementation process, the memory may be a non-transient (non-transitory) memory, for example, a Read Only Memory (ROM), which may be integrated on the same chip as the processor, or may be separately disposed on different chips.

It will be appreciated that the associated data interaction procedure, for example, sending an address may be a procedure for outputting an address from a processor, and receiving an address may be a procedure for receiving an input address by a processor. Specifically, the data output by the processor may be output to the transmitter, and the input data received by the processor may be from the receiver. Wherein the transmitter and receiver may be collectively referred to as a transceiver.

The processing means in the above eleventh aspect may be one or more chips. The processor in the processing device may be implemented by hardware or may be implemented by software. When implemented in hardware, the processor may be a logic circuit, an integrated circuit, or the like; when implemented in software, the processor may be a general-purpose processor, implemented by reading software code stored in a memory, which may be integrated in the processor, or may reside outside the processor, and exist separately.

In a twelfth aspect, there is provided a computer program product comprising: a computer program (which may also be referred to as code, or instructions) which, when executed, causes a computer to perform the method of any one of the possible implementations of the first to third aspects.

In a thirteenth aspect, a computer readable storage medium is provided, storing a computer program (which may also be referred to as code, or instructions) which, when run on a computer, causes the method of any one of the possible implementations of the first to third aspects described above to be performed.

A fourteenth aspect provides a communication system, including the foregoing session management network element, a second user plane network element, and a first user plane network element, where the session management network element is configured to perform the method in any one of the foregoing first aspect and any one of the foregoing possible implementation manners of the first aspect, and the second user plane network element is configured to perform the method in any one of the foregoing second aspect and any one of the foregoing possible implementation manners of the second aspect, and the first user plane network element is configured to perform the method in any one of the foregoing possible implementation manners of the third aspect and the third aspect.

Drawings

Fig. 1 is a schematic diagram of a communication system suitable for use in the method for session migration provided in an embodiment of the present application;

FIG. 2 is a schematic flow chart of a method of session migration provided by an embodiment of the present application;

FIG. 3 is a schematic flow chart of a method of session migration provided by an embodiment of the present application;

FIG. 4 is a schematic flow chart of a method of session migration provided by an embodiment of the present application;

FIG. 5 is a schematic diagram of session migration provided by an embodiment of the present application;

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

fig. 7 is a schematic diagram of a communication device provided in an embodiment of the present application;

FIG. 8 is a schematic block diagram of a communication device provided in another embodiment of the present application;

fig. 9 is a schematic diagram of a chip system according to an embodiment of the present application.

Detailed Description

The technical solution of the embodiment of the application can be applied to various communication systems, for example: a long term evolution (long term evolution, LTE) system, an LTE frequency division duplex (frequency division duplex, FDD) system, an LTE time division duplex (time division duplex, TDD) system, a fifth generation (5th generation,5G) system or New Radio (NR) system, a sixth generation (6th generation,6G) system or future communication system, and the like. The 5G mobile communication system described in the present application includes a non-independent Networking (NSA) 5G mobile communication system or an independent networking (SA) 5G mobile communication system. The communication system may also be a public land mobile network (public land mobile network, PLMN), a device-to-device (D2D) communication system, a machine-to-machine (machine to machine, M2M) communication system, an internet of things (internet of things, ioT) communication system, a internet of things (vehicle to everything, V2X) communication system, an unmanned aerial vehicle (uncrewed aerial vehicle, UAV) communication system, or other communication system.

The technical solutions in the embodiments of the present application will be described below with reference to the drawings in the embodiments of the present application. Wherein, in the description of the present application, "/" means that the related objects are in a "or" relationship, unless otherwise specified, for example, a/B may mean a or B; the term "and/or" in this application is merely an association relation describing an association object, and means that three kinds of relations may exist, for example, a and/or B may mean: there are three cases where a alone exists, where a and B exist together, and where B alone exists, where a, B may be singular or plural. Also, in the description of the present application, unless otherwise indicated, "a plurality" means two or more than two. In addition, in order to clearly describe the technical solutions of the embodiments of the present application, in the embodiments of the present application, the words "first", "second", and the like are used to distinguish the same item or similar items having substantially the same function and effect. It will be appreciated by those of skill in the art that the words "first," "second," and the like do not limit the amount and order of execution, and that the words "first," "second," and the like do not necessarily differ. Meanwhile, in the embodiments of the present application, words such as "exemplary" or "such as" are used to mean serving as examples, illustrations, or descriptions. Any embodiment or technique described herein as "exemplary" or "e.g." is not to be construed as preferred or advantageous over other embodiments or techniques. Rather, the use of words such as "exemplary" or "such as" is intended to present related concepts in a concrete fashion that may be readily understood.

In addition, the network architecture and the service scenario described in the embodiments of the present application are for more clearly describing the technical solution of the embodiments of the present application, and do not constitute a limitation on the technical solution provided in the embodiments of the present application, and as a person of ordinary skill in the art can know, with evolution of the network architecture and appearance of a new service scenario, the technical solution provided in the embodiments of the present application is also applicable to similar technical problems.

Fig. 1 is a network architecture suitable for use in embodiments of the present application, as shown in fig. 1, the network architecture may include:

1. user Equipment (UE): may be referred to as a terminal device, terminal, access terminal, subscriber unit, subscriber station, mobile station, remote terminal, mobile device, user terminal, wireless communication device, user agent, or user equipment. The terminal device may also be a cellular telephone, a cordless telephone, a session initiation protocol (session initiation protocol, SIP) phone, a wireless local loop (wireless local loop, WLL) station, a personal digital processor (personal digital assistant, PDA), a handheld device with wireless communication capabilities, a computing device or other processing device connected to a wireless modem, an in-vehicle device, an unmanned aerial vehicle, a wearable device, or a terminal device in a future communication system, etc., as the embodiments of the present application are not limited in this regard.

2. Access Network (AN): the network access function is provided for authorized users in a specific area, and transmission tunnels with different qualities can be used according to the level of the users, the requirements of services and the like. The access network may be an access network employing different access technologies. Current access network technologies include: radio access network technology employed in third generation (3rd generation,3G) systems, radio access network technology employed in fourth generation (4th generation,4G) systems, or next generation radio access network (next generation radio access network, NG-RAN) technologies (e.g., radio access technology employed in 5G systems, etc.).

An access network implementing access network functions based on wireless communication technology may be referred to as a radio access network (radio access network, RAN). The radio access network can manage radio resources, provide access service for the terminal, and further complete the forwarding of control signals and user data between the terminal and the core network.

The radio access network device may be, for example, a base station (NodeB), an evolved NodeB (eNB or eNodeB), a next generation base station node (next generation Node Base station, gNB) in a 5G mobile communication system, a base station in a future mobile communication system, or an Access Point (AP) in a wifi wireless hotspot system, or the like, or may be a radio controller in a cloud radio access network (cloud radio access network, CRAN) scenario, or may be a relay station, an access point, an in-vehicle device, a drone, a wearable device, a network device in a future communication system, or the like. The embodiment of the application does not limit the specific technology and the specific equipment form adopted by the wireless access network equipment.

3. Access management network element: the method is mainly used for mobility management and access management, is responsible for transferring user policies between user equipment and policy control function (policy control function, PCF) network elements, and the like, and can be used for realizing other functions except session management in the functions of a mobility management entity (mobile management entity, MME). For example, access authorization (authentication) functions.

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

4. Session management network element: the method is mainly used for session management, allocation and management of internet protocol (Internet protocol, IP) addresses of user equipment, selection of termination points of manageable user plane functions, policy control and charging function interfaces, downlink data communication and the like.

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

5. User plane network element: for packet routing and forwarding, quality of service (quality of services, qoS) handling of user plane data, completion of user plane data forwarding, session/flow level based billing statistics, bandwidth limiting functions, etc.

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

6. Data network element: for providing a network for transmitting data.

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

7. Policy control network element: for guiding the network behavior through a unified policy framework, providing policy rule information for control plane function network elements (e.g., AMF, SMF network elements, etc.), etc.

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

In the architecture shown in fig. 1, the interface names and functions between the network elements are as follows:

1. n1: the interface between the AMF and the UE may be used to communicate QoS control rules, etc. to the UE.

2. N2: the interface between the AMF and the RAN may be used to transfer radio bearer control information, etc., from the core network side to the RAN.

3. And N3: and the interface between the RAN and the UPF is used for transmitting uplink and downlink user plane data between the RAN and the UPF.

4. N4: the interface between SMF and UPF can be used to transfer information between control plane and user plane, including control plane-oriented forwarding rule, qoS control rule, flow statistics rule, etc. and user plane information reporting.

5. N6: the interface between UPF and DN is used to transfer the uplink and downlink user data flow between UPF and DN.

6. N7: the interface between the SMF and PCF is used to deliver user policies, etc.

7. N9: the user interface between UPF and UPF is used to transfer the uplink and downlink user data flow between UPF.

8. N14: the interface between the AMFs is used for transferring UE context, etc.

9. N15: and an interface between the AMF and the PCF is used for transmitting access network discovery strategies, user routing strategies and the like.

It should be understood that the network architecture applied to the embodiments of the present application is merely illustrative, and the network architecture applicable to the embodiments of the present application is not limited thereto, and any network architecture capable of implementing the functions of the network elements described above is applicable to the embodiments of the present application.

It should also be understood that AMF, SMF, UPF, PCF and the like shown in fig. 1 may be understood as network elements in the core network for implementing different functions, e.g. may be combined into network slices as required. The core network elements may be independent devices, or may be integrated in the same device to implement different functions, and the specific form of the network elements is not limited in this application.

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 employing other naming in 5G networks as well as other networks in the future. For example, in a 6G network, some or all of the above networks may follow the terminology in 5G, other names may also be used, etc. 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. In addition, the names of the information (or signaling) transmitted between the above-mentioned network elements are also merely examples, and the functions of the information itself are not limited in any way.

Based on the network architecture shown in fig. 1, before the UE performs service transmission, the UE first accesses the UPF of the 5G core network through the access network device, and creates a session through the UPF, so that the UE may perform service transmission through the created session. In the process of service transmission of the UE, if the UPF connected to the UE cannot continue to provide services for the UE, for example, the UPF fails, or the UPF needs to be upgraded, a session of the UE is disconnected from the UPF, so that the service transmission of the UE is interrupted.

In view of this, the embodiments of the present application provide a method for session migration in order to avoid interruption of service transmission of a UE.

Fig. 2 shows a schematic flow chart of a method 200 for session migration provided in an embodiment of the present application, the method 200 may include the following steps:

s210, the session management network element sends the address and the downlink tunnel information to the first user plane network element.

Correspondingly, the first user plane network element receives the address and the downlink tunnel information from the session management network element.

The address is an address of a terminal device served by the second user plane network element, and the address corresponds to a first session established by the second user plane network element for the terminal device, that is, the first session is used for transmitting a data packet, when the data packet is a downlink data packet, a destination address of the downlink data packet is the address, and when the data packet is an uplink data packet, a source address of the uplink data packet is the address. Illustratively, the address is an IP address.

The downlink tunnel information corresponds to the first session, and the downlink tunnel information includes an interface address of the access network device. Optionally, the downlink tunnel information further includes an identifier of a downlink transmission channel, where the downlink transmission channel is a downlink transmission channel of the first session between the access network device and the second user plane network element. For example, in a 5G communication system, the downlink tunnel information is downlink N3 tunnel information, the interface address of the access network device is an N3 interface address of the access network device, and the identification of the downlink transmission channel includes a tunnel endpoint identification (tunnel endpoint identifier, TEID) of the downlink transmission channel. The access network device is an access network device to which the terminal device accesses. The first session may also be referred to as a session to be migrated.

After the first user plane network element receives the address and the downlink tunnel information, a second session can be established for the terminal device according to the address and the downlink tunnel information. For example, the first user plane network element may establish a second session corresponding to the address for the terminal device according to the address, and establish a downlink transmission channel between the access network device and the first user plane network element for the second session according to the downlink tunnel information. The address corresponds to the second session, and it is understood that the destination address of the downstream data packet of the second session is the address, or the source address of the upstream data packet of the second session is the address. The second session may also be understood as a session after the session management network element migrates the first session to the first user plane network element.

For example, the session management network element sends the address and the downlink tunnel information to the first user plane network element through N4 session establishment request (N4 session establishment request) information.

Optionally, before the session management network element sends the address and the downlink tunnel information to the first user plane network element, the method 200 further includes S230: the session management network element determines to migrate at least one session of the second user plane network element, the at least one session comprising the first session. The at least one session may include all sessions of the second user plane network element, or may include a portion of the sessions of the second user plane network element, which is not limited in this embodiment of the present application. The at least one session may also be referred to as at least one session to be migrated.

The method for determining the migration of at least one session of the second user plane network element by the session management network element is not limited.

In a possible implementation manner, the session management network element determines a manner of migrating at least one session of the second user plane network element, including: the session management network element receives first indication information from the second user plane network element or the first user plane network element, wherein the first indication information is used for indicating migration of at least one session of the second user plane network element; and the session management network element determines to migrate the at least one session according to the first indication information.

Illustratively, the first indication information includes at least one data network name (data network name, DNN), and is used to indicate that a session of the second user plane network element corresponding to each DNN of the at least one DNN is migrated.

The first indication information is used for indicating that at least one session of the second user plane network element is migrated to the first user plane network element. The identification of the first user plane network element comprises one or more of: an Identifier (ID) of the first user plane network element, an IP address of the first user plane network element, or a full-size domain name (fully qualified domain name, FQDN) of the first user plane network element.

The second user plane element sends the first indication information to the session management element according to a second instruction received from the user, where the second instruction is received by the second user plane element through a User Interface (UI). The second instructions are for indicating to migrate at least one session of the second user plane network element.

Illustratively, the second instruction received by the second user plane network element through the UI includes at least one DNN, and the second instruction is configured to instruct the second user plane network element to migrate a session corresponding to each DNN in the at least one DNN.

For example, the second instruction received by the second user plane network element through the UI may further include an identifier of the first user plane network element, where the second instruction is used to instruct migration of at least one session of the second user plane network element to the first user plane network element.

The second instruction received by the second user plane network element through the UI may be input by the user through the UI. For example, the second instruction input by the user through the UI may be any one of the following: "migrate session of the second user plane network element", "migrate session of the second user plane network element corresponding to dnn#1", "identity of the second user plane network element and dnn#1", or "identity of the second user plane network element and identity of the first user plane network element". Wherein the identification of the second user plane network element comprises one or more of: the ID of the second user plane network element, the IP address of the second user plane network element, or the FQDN of the second user plane network element. The second instruction input by the user through the UI may also be in other forms, which are not limited in the embodiment of the present application.

For example, the second instruction received by the second user plane network element is used for indicating to migrate at least one session of the second user plane network element, and then the second user plane network element sends first indication information to the session management network element according to the second instruction, where the first indication information is used for indicating to migrate at least one session of the second user plane network element. For example, the second instruction is used for indicating to migrate the session corresponding to each DNN in at least one DNN of the second user plane network element, and then the second user plane network element sends first indication information to the session management network element according to the second instruction, where the first indication information is used for indicating to migrate the first session set of the second user plane network element, and the session in the first session set is the session corresponding to each DNN in at least one DNN in the second instruction.

Similarly, the first user plane element sends the first indication information to the session management element according to a third instruction received from the user, where the third instruction is received by the first user plane element through the UI. The manner in which the first user plane network element sends the first indication information to the session management network element according to the third instruction may refer to the manner in which the second user plane network element sends the first indication information to the session management network element according to the second instruction. The third instruction may be input by the user through the UI, and the form of the third instruction input by the user through the UI may refer to the form of the second instruction above.

For example, the first user plane network element or the second user plane network element may send the first indication information to the session management network element by means of packet forwarding control protocol (packet forwarding control protocol, PFCP) node reporting request (PFCP node report request) information.

In a possible implementation manner, the session management network element determines a manner of migrating at least one session of the second user plane network element, including: the session management network element receives a first instruction from a user, wherein the first instruction is used for indicating to migrate at least one session of the second user plane network element; the session management network element determines to migrate the at least one session according to the first instruction.

Illustratively, the first instruction received by the session management network element includes at least one DNN, and the first instruction is configured to instruct migration of a session of the second user plane network element corresponding to each DNN of the at least one DNN.

For example, the first instruction received by the session management network element may further include an identifier of the first user plane network element, and the first instruction is used to instruct migration of at least one session of the second user plane network element to the first user plane network element.

The first instruction received by the session management network element may be input by the user through the UI, and the form of the first instruction input by the user through the UI may refer to the form of the second instruction above.

In a possible implementation manner, the session management network element determines a manner of migrating at least one session of the second user plane network element, including: if the second user plane network element fails, the session management network element determines to migrate at least one session of the second user plane network element. It will be appreciated that in the event of a failure of the second user plane network element, the at least one session includes all sessions of the second user plane network element.

The session management network element may determine whether the second user plane network element is malfunctioning by detecting an N4 link between the session management network element and the second user plane network element. For example, after the session management network element sends the heartbeat request (heartbeat request) information to the second user plane network element through the N4 link, if the session management network element does not receive the heartbeat response (heartbeat response) information from the second user plane network element, the session management network element determines that the second user plane network element fails.

The first user plane network element is not limited in the embodiment of the present application.

In a possible implementation manner, if the second user plane network element is a primary user plane network element, and the first user plane network element is a standby user plane network element, that is, when the first user plane network element and the second user plane network element are primary and standby, if the session management network element determines to migrate at least one session of the primary user plane network element (i.e., the second user plane network element), the session management network element migrates the at least one session to the standby user plane network element (i.e., the first user plane network element). It should be particularly understood that the first user plane network element and the second user plane network element are primary and secondary, including two different situations, the first is that the first user plane network element is a primary user plane network element, the second user plane network element is a secondary user plane network element, the second is that the first user plane network element is a secondary user plane network element, the second user plane network element is a primary user plane network element, and both situations can be referred to as "the first user plane network element and the second user plane network element are primary and secondary" each other. The above description is applicable to any embodiment of the present application, and will not be repeated.

In a possible implementation manner, if the second user plane network element is a standby user plane network element, and the first user plane network element is a primary user plane network element, that is, when the first user plane network element and the second user plane network element are primary and standby, if the session management network element determines to migrate at least one session of the standby user plane network element (i.e., the second user plane network element), the session management network element migrates the at least one session to the primary user plane network element (i.e., the first user plane network element).

In one possible implementation manner, if there is no user plane network element that is active with the second user plane network element, the first user plane network element may be any one of the available user plane network elements, or the first user plane network element may be the user plane network element with the lowest load.

Optionally, if the first user plane element is a primary user plane element, the second user plane element is a standby user plane element, and since the second user plane element is upgraded to the primary user plane element after the session of the first user plane element is migrated to the second user plane element, the session management element determines that at least one session of the second user plane element is migrated, the method 200 further includes S240: the session management network element sends second indication information to the second user plane network element, wherein the second indication information is used for indicating the second user plane network element to be degraded from the active user plane network element to the standby user plane network element. For example, the session management network element sends the second indication information to the second user plane network element through the heartbeat request information.

And after the second user plane network element receives the second indication information, degrading the second indication information into a standby user plane network element by the active user plane network element. For example, the second user plane network element issues (advertisement) second routing information according to the second indication information, the second routing indicated by the second routing information is lower in priority than the first routing indicated by the first routing, and the first routing corresponds to the first routing information issued by the first user plane network element. The second route instructs the first node to send the downlink data packet with the destination address being the first address segment to the second user plane network element, and the first node is the last hop node of the second user plane network element. The first route instructs the second node to send the downlink data packet with the destination address being the first address segment to the first user plane network element, and the second node is the last hop node of the first user plane network element. The first address field includes an address of the terminal device.

Optionally, after the second user plane network element is downgraded from the active user plane network element to the standby user plane network element according to the second indication information, the method 200 further includes S250: the second user plane network element sends third notification information to the session management network element, wherein the third notification information is used for indicating that the second user plane network element is degraded from the active user plane network element to the standby user plane network element.

Optionally, after the first user plane network element establishes the second session for the terminal device according to the address and the downlink tunnel information, the method 200 further includes S260: the first user plane network element sends uplink tunnel information to the session management network element, wherein the uplink tunnel information corresponds to the second session. The uplink tunnel information includes an interface address of the first user plane network element. Optionally, the uplink tunnel information further includes an identifier of an uplink transmission channel, where the uplink transmission channel is an uplink transmission channel of the second session between the access network device and the second user plane network element. For example, in the 5G communication system, the uplink tunnel information is uplink N3 tunnel information, the interface address of the first user network element is an N3 interface address of the first user plane network element, and the identifier of the uplink transmission channel includes the TEID of the uplink transmission channel. For example, the first user plane network element may send uplink N3 tunnel information to the session management network element through N4 session setup response (N4 session establishment response) information.

Optionally, after the first user plane network element establishes the second session for the terminal device according to the address and the downlink tunnel information, the method 200 further includes: the first user plane network element issues third routing information, the third routing information indicates a third route, and the third route indicates the second node to send a downlink data packet with the destination address being the address to the first user plane network element.

S220, the session management network element sends the uplink tunnel information to the access network device.

Correspondingly, the access network device receives the uplink tunnel information from the session management network element.

After the access network equipment receives the uplink tunnel information, an uplink transmission channel of the second session between the access network equipment and the first user plane network element is established according to the uplink tunnel information.

The session management network element sends the uplink tunnel information to the access network device through the access management network element. For example, the session management network element may send uplink tunnel information to the access management network element through AMF server interface_communication_n1n2 message forwarding (namf_communication_n1n2message transfer) information. The AMF servitization interface_communication_n1n2 message forwarding information includes N2 session management (session management, SM) information and N1 SM container (container), and the N2 SM information includes uplink tunnel information. Further, the access management network element may send uplink tunnel information to the access network device via protocol data unit (protocol data unit, PDU) session resource modification request (PDU session resource modify request) information. For example, the PDU session resource modification request information includes N2 SM information, and the N2 SM information includes uplink tunnel information. Correspondingly, after receiving the PDU session resource modification request information, the access network device analyzes the N2 SM information to obtain uplink tunnel information.

The method for the session management network element to acquire the uplink tunnel information is not limited in the embodiment of the application. For example, the session management network element is preconfigured with uplink tunnel information. Or before the session management network element sends the address and the downlink tunnel information to the first user plane network element, the session management network element receives the uplink tunnel information from the first user plane network element. Or after the session management network element sends the address and the downlink tunnel information to the first user plane network element, the session management network element receives the uplink tunnel information from the first user plane network element.

Optionally, after S210, or after S220, the method 200 further includes S270: the session management network element sends third indication information to the second user plane network element, wherein the third indication information is used for indicating the second user plane network element to delete the session context of the first session. For example, the session management network element sends third indication information to the second user plane network element through N4 session delete (N4 session delete) information.

It may be appreciated that in case the second user plane network element is not malfunctioning, the session management network element may send the third indication information to the second user plane network element.

It should be noted that, if the session management network element determines to migrate the plurality of sessions of the second user plane network element, the session management network element sequentially migrates the plurality of sessions of the second user plane network element according to the manner described in S210 and S220.

Optionally, after the session management network element migrates the session to be migrated of the second user plane network element, the method 200 further includes S280: the session management network element sends first notification information to the first user plane network element, wherein the first notification information is used for indicating that at least one session to be migrated of the second user plane network element has been migrated to the first user plane network element. For example, the session management network element may send the first notification information to the first user plane network element through the heartbeat request information.

Optionally, if the first user plane network element and the second user plane network element are active and standby, and the first user plane network element is a standby user plane network element, after the first user plane network element receives the first notification information, the method 200 further includes S290: the first user plane network element sends second notification information to the session management network element, wherein the second notification information is used for indicating that the first user plane network element is updated from the standby user plane network element to the active user plane network element.

The upgrading of the first user plane network element from the standby user plane network element to the active user plane network element comprises the following cases:

in case 1, a second user plane network element that is active with a first user plane network element cannot normally provide user plane services, for example, the second user plane network element fails, or is upgraded or restarted, and then the first user plane network element is upgraded from the standby user plane network element to the active user plane network element;

In case 2, the first user plane network element issues the first routing information, and the first routing corresponding to the first routing information has higher priority than the second routing corresponding to the second routing issued by the second user plane network element, so that the first user plane network element is updated to the active user plane network element by the standby user plane network element.

In the embodiment of the application, the session management network element sends the address of the terminal equipment and the downlink tunnel information of the first session to the first user plane network element, so that the first user plane network element can establish a second session for the terminal equipment according to the address and the downlink tunnel information, and the session management network element sends the uplink tunnel information of the second session to the access network equipment, so that the access network equipment can establish an uplink transmission channel of the second session between the access network equipment and the first user plane network element according to the uplink tunnel information, thereby realizing the migration of the session of the terminal equipment from the second user plane network element to the first user plane network element. Because the first session and the second session correspond to the same address, the service transmitted by the terminal equipment based on the session will not be interrupted in the process of migrating the session of the terminal equipment from the second user plane network element to the first user plane network element.

In addition, even if the second user plane network element fails, according to the method provided by the application, the terminal equipment does not need to be disconnected (i.e. release the session) and then be disconnected again (i.e. reestablish the session), so that the service transmitted by the terminal equipment can be prevented from being interrupted for a long time.

The application of the session migration method provided in the embodiment of the present application in a 5G communication system is described below with reference to fig. 3 or fig. 4. It should be noted that ue#1 in fig. 3 or fig. 4 is an example of the terminal device shown in fig. 2, smf#1 and smf#2 are examples of the session management network element shown in fig. 2, RAN is an example of the access network device shown in fig. 2, and AMF is an example of the access management network element shown in fig. 2. In migrating a session of upf#1 to upf#2, upf#1 is an example of the second user plane network element shown in fig. 2, and upf#2 is an example of the first user plane network element shown in fig. 2; alternatively, in migrating the session of upf#2 to upf#1, upf#2 is an example of the second user plane network element shown in fig. 2, and upf#1 is an example of the first user plane network element shown in fig. 2. It should be further noted that, in the following embodiments, only the case where the upf#1 is docked with the smf#1 and the smf#1 is described as an example, the upf#1 may also dock more SMFs, or the upf#1 is docked with one SMF, which is not limited in this embodiment of the present application.

In connection with fig. 2, fig. 3 shows a schematic flow chart of a method 300 of session migration provided by an embodiment of the present application. The method 300 shown in fig. 3 may include the steps of:

s301, upf#1 transmits PFCP node report request information #1 to smf#1.

Accordingly, smf#1 receives PFCP node report request information #1 from smf#1.

The PFCP node report request information #1 includes indication information #1 for indicating migration of at least one session of the UPF #1, and further description of the indication information #1 may refer to the description of the first indication information in the above S230.

Optionally, after the smf#1 receives the PFCP node reporting request information#1, the PFCP node reporting response (PFCP node report response) information#1 may also be sent to the upf#1.

S302, upf#1 transmits PFCP node report request information #2 to smf#2.

Accordingly, smf#2 receives PFCP node report request information#2 from upf#1.

The PFCP node report request information #2 includes indication information #2 for indicating migration of at least one session of the UPF #1, and further description of the indication information #2 may refer to the description of the first indication information in the above S230.

Optionally, after the smf#2 receives the PFCP node report request information#2, the smf#2 may further transmit PFCP node report response information#2 to the upf#1.

Note that the indication information #1 and the indication information #2 may be the same or different, and the embodiment of the present application is not limited thereto. For example, if smf#1 is used to serve a UE subscribed to dnn#1 and smf#2 is used to serve a UE subscribed to dnn#2, the indication information #1 may include dnn#1 and the indication information #2 may include dnn#2.

It should also be noted that, in the embodiment of the present application, S301 and S302 are performed by using the method 300 as an example, S301 may be an optional step, or S302 may be an optional step.

Illustratively, if the upf#1 receives the second instruction through the UI, the PFCP node report request information #1 is transmitted to the smf#1 according to the second instruction, and the PFCP node report request information #2 is transmitted to the smf#2 according to the second instruction. The relevant description of the second instruction may refer to S230 in the method 200 above.

Illustratively, in the case where upf#1 determines that an upgrade is about to be performed or that a restart is about to be performed, PFCP node report request information #1 is transmitted to smf#1, and PFCP node report request information #2 is transmitted to smf#2. For example, if UPF#1 is configured by a user as a periodic upgrade, UPF#1 can determine that an upgrade is about to be performed according to the period of the upgrade.

After the smf#1 receives the instruction information #1, at least one session of the upf#1 is migrated according to the instruction of the instruction information # 1. Similarly, after the smf#2 receives the instruction information #2, at least one session of the upf#1 is migrated according to the instruction of the instruction information #2.

The following describes the procedure of session migration, taking as an example the migration of session #1 of UPF #1 by SMF #2, in conjunction with S303 to S310.

S303, smf#2 transmits N4 session setup request information to upf#2.

Accordingly, upf#2 receives N4 session setup request information from smf#2.

The N4 session establishment request information includes an IP address and downlink N3 tunnel information of the ue#1, and the IP address and downlink N3 tunnel information of the ue#1 correspond to the session#1 established by the upf#1 for the ue#1. The IP address of ue#1 is hereinafter denoted as IP address#1.

After receiving the IP address #1 and the downstream N3 tunnel information, the UPF #2 establishes a session #2 corresponding to the IP address #1 according to the IP address #1, and establishes a downstream transmission channel of the session #2 between the RAN and the UPF #2 according to the downstream N3 tunnel information.

For more description of S303, reference may be made to S210 in method 200 above.

S304, UPF#2 transmits N4 session establishment response information to SMF#2.

Accordingly, smf#2 receives N4 session setup response information from upf#2.

After upf#2 establishes session#2 for ue#1, N4 session establishment response information including uplink N3 tunnel information of session#2 is transmitted to smf#2. After the smf#2 receives the N4 session setup response information, it is determined that the upf#2 has established a session#2 for the ue#1.

S304 may refer to S260 in the method 200 above.

Optionally, the method 300 further comprises S305.

S305, upf#2 publishes routing information #1.

Route information #1 (an example of third route information) indicates route #1 (an example of third route), route #1 indicates that node #1 transmits a downstream packet whose destination address is IP address #1 to UPF #2, and node #1 is the last-hop node of UPF #2.

If the upf#2 does not issue the route information #1, or if the route indicated by the route information issued by the upf#2 does not include the route #1, the upf#2 issues the route information #1 after receiving the IP address #1.

It will be appreciated that after the upf#2 transmits the route information #1, if the destination address of the downstream packet received by the node#1 is the IP address #1, the node#1 transmits the downstream packet to the upf#2 according to the route#1.

S306, smf#2 sends namf_communication_n1n2 message forwarding information to AMF.

Accordingly, the AMF receives namf_communication_n1n2 message forwarding information from smf#2.

The Namf communication N1N2 message forwarding information includes uplink N3 tunnel information of session #2.

S307, the AMF sends the N2 PDU session resource modification request information to the RAN.

Accordingly, the RAN receives the N2 PDU session resource modification request information from the AMF.

The N2 PDU session resource modification request information includes uplink N3 tunnel information of session # 2.

For more description of S306 and S307 reference may be made to S220 in the method 200 above.

After receiving the uplink N3 tunnel information of session #2, the RAN establishes an uplink transmission channel between the RAN and UPF #2 for session #2 according to the uplink N3 tunnel information.

S308, the RAN sends N2 PDU session resource modification response (PDU session resource modification response) information to the AMF.

Accordingly, the AMF receives the N2 PDU session resource modification response information from the RAN.

After the RAN establishes the uplink transmission channel between the RAN and the UPF #2, the RAN transmits N2 PDU session resource modification response information to the AMF. The N2 PDU session resource modification response information is response information of the N2 PDU session resource modification request information, and the N2 PDU session resource modification response information includes N2 SM information, where the N2 SM information is used to indicate that the RAN has established an uplink transmission channel of session #2 between the RAN and UPF # 2.

S309, the AMF sends nsmf_pdu session_update SM context request (nsmf_pduse_ UpdateSMContext Request) information to smf#2.

Accordingly, smf#2 receives nsmf_pdu session_update SM context request information from the AMF. Nsmf_pdu session_update SM context request information includes N2 SM information, and smf#2 may determine from the N2 SM information that the RAN has established an uplink transmission channel of session#2 between the RAN and upf#2.

Optionally, smf#2 may also send nsmf_pdu session_update SM context response (nsmf_pduse_ UpdateSMContext Response) information to the AMF.

S310, smf#2 transmits N4 session deletion information to upf#1.

Accordingly, upf#1 receives N4 session deletion information from smf#2.

After the smf#2 determines that upf#2 established session#2 for ue#1 and determines that the RAN established an uplink transport channel for session#2 between the RAN and upf#2, N4 session deletion information may be transmitted to upf#1.

After the upf#1 receives the N4 session deletion information, the context of the session#1 is deleted according to the N4 session deletion information.

Optionally, after upf#1 deletes the context of session#1, upf#1 may further send N4 session deletion response information to smf#2.

It should be noted that, based on the above steps S303 to S310, after the upf#2 establishes the session#2 for the ue#1 and the RAN establishes the uplink transmission channel between the RAN and the upf#2, the session#2 indicates that the session#1 has been migrated to the upf#2, and the session#2 may be understood as a session after the SMF migrates the session#1 to the upf#2.

If the smf#2 determines to migrate the plurality of sessions of the upf#1 according to the received instruction information #2, the smf#2 sequentially migrates the plurality of sessions of the upf#1 in the manner described in S303 to S310.

And the smf#1 migrates at least one session of the upf#1 in the manner described in S303 to S310 according to the instruction of the instruction information #1.

In addition, during the process of the SMF (smf#1 or smf#2) migrating the session of upf#1, if the SMF receives new session establishment request information, the SMF selects upf#2 to establish the session. For example, if the smf#2 receives session setup request information from the ue#2 during the migration of the session#1 by the smf#2, the smf#2 selects the upf#2 to set up a session for the ue#2.

Optionally, the method 300 further comprises S311.

S311, upf#1 publishes routing information #2.

Route #2 (an example of the second route) indicated by route information #2 (an example of the second route) is lower in priority than route #3 (an example of the first route), and route #3 corresponds to route information #3 (an example of the first route information) transmitted by UPF #2. Route #2 instructs node #2 to send the downstream packet with the destination address being the first address segment to UPF #1, route #3 instructs node #1 to send the downstream packet with the destination address being the first address segment to UPF #2, node #2 is the upstream hop node of UPF #1, and the first address segment includes IP address #1.

If the upf#1 and the upf#2 have a primary-backup relationship, and the upf#1 is a primary UPF, after the upf#1 determines that all the sessions to be migrated are migrated, the upf#1 issues the routing information #2. For example, after the instruction information #1 sent by the UPF #1 is used for instructing to migrate the session #3 of the UPF #1, the instruction information #2 is used for instructing to migrate the session #1 of the UPF #1, the UPF #1 receives the N4 session deletion information for instructing to delete the session context of the session #3, and the UPF #1 determines that all the sessions to be migrated are completed after receiving the N4 session deletion information for instructing to delete the session context of the session #1, the UPF #1 issues the routing information #2.

It will be appreciated that after UPF#1 publishes routing information #2, UPF#1 is downgraded from a primary UPF to a backup UPF.

Optionally, after the SMF (smf#1 and smf#2) migrates at least one session of the upf#1 according to the received indication information, the method 300 further includes S312 and S313.

S312, the smf#2 transmits heartbeat request information #1 to the upf#2.

Accordingly, upf#2 receives heartbeat request information #1 from smf#2.

Optionally, after receiving the heartbeat request information #1, the upf#2 may also send heartbeat response information #1 to the smf#2.

S313, the smf#1 transmits heartbeat request information #2 to the upf#2.

Accordingly, upf#2 receives heartbeat request information #2 from smf#1.

Optionally, after receiving the heartbeat request information #2, the upf#2 may also send heartbeat response information #2 to the smf#1.

The heartbeat-request information #1 and the heartbeat-request information #2 each include notification information #1 (an example of first notification information), the notification information #1 indicating that at least one session of the UPF #1 has migrated to the UPF #2.

S312 and S313 may refer to S280 in the above method 200.

Correspondingly, if the upf#1 and the upf#2 have a primary-backup relationship, and the upf#2 is a backup UPF, after the upf#2 receives notification information #1 from the smf#1 and the smf#2, the upf#2 determines that the session to be migrated of the upf#1 has been migrated to the upf#2 according to the notification information #1, and further the upf#2 can be upgraded from the backup UPF to the primary UPF. UPF #2 upgrades from a standby UPF to a primary UPF for a description of the primary UPF, reference may be made to the method 200 above.

Optionally, after upf#2 is upgraded from the standby UPF to the primary UPF, the method 300 further includes S314 and S315.

S314, the upf#2 transmits heartbeat request information #3 to the smf#2.

Accordingly, smf#2 receives heartbeat request information #3 from upf#2.

Optionally, after the smf#2 receives the heartbeat request information #3, the heartbeat response information #3 may also be sent to the upf#2.

S315, upf#2 transmits heartbeat request information #4 to smf#1.

Accordingly, smf#1 receives heartbeat request information #4 from upf#2.

Optionally, after the smf#1 receives the heartbeat request information #4, the heartbeat response information #4 may also be sent to the upf#2.

The heartbeat-request information #3 and the heartbeat-request information #4 each include notification information #2 (an example of second notification information), the notification information #2 indicating that the UPF #2 has been upgraded from the standby UPF to the primary UPF.

S314 and S315 may refer to S290 in the method 200 above.

Note that, if the upf#2 does not transmit the heartbeat request information #3, the smf#2 determines that the upf#2 is updated from the backup UPF to the primary UPF after transferring the session to be transferred of the upf#1 to the upf#2 according to the instruction information # 2. If the upf#2 does not send the heartbeat request information #4, the smf#1 transfers the session to be transferred of the upf#1 to the upf#2 according to the instruction information #1, and then determines that the upf#2 is upgraded from the standby UPF to the primary UPF.

Alternatively, if after a period of time, upf#1 returns to normal, e.g., after upf#1 completes an upgrade or completes a restart, upf#1 may continue to provide user plane services to the UE, upf#1 may instruct smf#1 and/or smf#2 to migrate the session of upf#2 to upf#1. In this case, the method 300 may further include one or more steps of S316 to S323.

S316, upf#1 transmits PFCP node-report request information #3 to smf#1.

Accordingly, smf#1 receives PFCP node report request information #3 from smf#1.

The PFCP node report request information #3 includes indication information #3 for indicating migration of at least one session of UPF #2 to UPF #1, and further description of the indication information #3 may refer to the description of the first indication information in S230 above.

Optionally, after the smf#1 receives the PFCP node report request information#3, the PFCP node report response information#3 may also be transmitted to the upf#1.

S317, upf#1 transmits PFCP node report request information #4 to smf#2.

Accordingly, smf#2 receives PFCP node report request information #4 from upf#1.

The PFCP node report request information #4 includes indication information #4 for indicating migration of at least one session on UPF #2 to UPF #1, and further description of the indication information #4 may refer to the first indication information in S230 above.

Optionally, after the smf#2 receives the PFCP node report request information#4, the PFCP node report response information#4 may also be transmitted to the upf#1.

Note that the indication information #3 and the indication information #4 may be the same or different, and the embodiment of the present application is not limited thereto. For example, if smf#1 is used to serve a UE subscribed to dnn#1 and smf#2 is used to serve a UE subscribed to dnn#2, the indication information #3 may include dnn#1 and the indication information #4 may include dnn#2.

It should also be noted that, in the embodiment of the present application, S315 and S316 are performed by the method 300 as an example, S315 may be an optional step, or S316 may be an optional step.

Illustratively, if the upf#1 receives a third instruction through the UI, the PFCP node report request information #3 is transmitted to the smf#1 according to the third instruction, and the PFCP node report request information #4 is transmitted to the smf#2 according to the third instruction. The third instruction may refer to the description in the above method S230.

Illustratively, after upf#1 completes the upgrade or completes the restart, PFCP node report request information #3 is transmitted to smf#1, and PFCP node report request information #4 is transmitted to smf#2.

Optionally, the method 300 further comprises S318.

S318, upf#1 publishes routing information #4.

Route #4 (an example of the first route) indicated by route information #4 (an example of the first route) has a higher priority than route #3 (an example of the second route), and route #4 indicates that node #2 transmits a downstream packet whose destination address is the first address field to UPF #1.

As described above, if the upf#1 has a primary-backup relationship with the upf#2, and the upf#1 is the primary UPF, after the upf#1 determines that all the sessions to be migrated are migrated, the routing information #2 is published and downgraded from the primary UPF to the backup UPF. Further, after the upf#1 returns to normal, the upf#1 may issue the routing information #4 in order to re-upgrade to the primary UPF, thereby re-upgrading from the backup UPF to the primary UPF.

Optionally, in the case that the SMFs (smf#1 and smf#2) determine to migrate the session of the upf#2 according to the received indication information, the method 300 further includes S319 and S320.

S319, the smf#2 transmits heartbeat request information #5 to the upf#2.

Accordingly, upf#2 receives heartbeat request information #5 from smf#2.

Optionally, after receiving the heartbeat request information #5, the upf#2 may also send heartbeat response information #5 to the smf#2.

S320, smf#1 transmits heartbeat request information #6 to upf#2.

Accordingly, upf#2 receives heartbeat request information #6 from smf#1.

Optionally, after receiving the heartbeat request information #6, the upf#2 may also send heartbeat response information #6 to the smf#1.

The heartbeat-request information #5 and the heartbeat-request information #6 each include indication information #5 (an example of second indication information), the indication information #5 being used to indicate that the UPF #2 is downgraded from the primary UPF to the backup UPF.

Accordingly, UPF#2 is downgraded from the primary UPF to the backup UPF according to the indication information # 5.

S319 and S320 may refer to S240 in the above method 200.

Degradation of UPF #2 from a primary UPF to a backup UPF includes the following: case 1, upf#1 publishes routing information #4, in which case upf#1 upgrades to the primary UPF and upf#2 downgrades to the backup UPF; in case 2, if the upf#2 issues the route information #3, and the route #3 indicated by the route information #3 is lower in priority than the route #2 or the route #4, the upf#2 is downgraded from the primary UPF to the backup UPF. If the upf#1 issues the route information #2 and does not issue the route information #4, the priority of the route#3 is lower than the priority of the route#2, and if the upf#1 issues the route information #4, the priority of the route#3 is lower than the priority of the route#4.

Optionally, after the upf#2 is downgraded from the primary UPF to the backup UPF, the method 300 further includes S321 and S322.

S321, the upf#2 transmits heartbeat request information #7 to the smf#2.

Accordingly, smf#2 receives heartbeat request information #7 from upf#2.

Optionally, after the smf#2 receives the heartbeat request information#7, the heartbeat response information#7 may also be sent to the upf#2.

S322, upf#2 transmits heartbeat request information #8 to smf#1.

Accordingly, smf#1 receives heartbeat request information #8 from upf#2.

Optionally, after the smf#1 receives the heartbeat request information #8, the heartbeat response information #8 may also be sent to the upf#2.

The heartbeat-request information #7 and the heartbeat-request information #8 each include notification information #3 (an example of third notification information), the notification information #3 indicating that the UPF #2 has been downgraded from the primary UPF to the backup UPF.

S321 and S322 may refer to S250 in the above method 200.

Note that, if upf#2 does not transmit heartbeat request information #7, smf#2 determines that upf#2 is degraded from the primary UPF to the backup UPF after receiving PFCP node report request information # 4. If upf#2 does not transmit heartbeat request information #8, smf#1 determines that upf#2 is downgraded from the primary UPF to the backup UPF after receiving PFCP node report request information # 3.

S323, smf#1 and/or smf#2 migrates at least one session of upf#2 to upf#1.

After the smf#1 receives the instruction information #3, at least one session of the upf#2 is migrated to the upf#1 according to the instruction of the instruction information # 3. Similarly, after the smf#2 receives the instruction information #4, at least one session of the upf#2 is migrated to the upf#1 according to the instruction of the instruction information # 4.

S323 can refer to the description of S303 to S310 above.

In this embodiment of the present application, the upf#1 may send indication information (for example, indication information #1 or indication information # 2) to the corresponding SMFs (for example, smf#1 and smf#2) according to the received second instruction, or in the case that the upf#1 is to be updated or restarted, so as to instruct the SMFs to migrate at least one session of the upf#1 to the upf#2, thereby avoiding service interruption caused by the failure of the upf#1 to normally provide services, and improving continuity and stability of the services.

In addition, if the upf#1 and the upf#2 have a primary-backup relationship, the SMF may send notification information #1 to the upf#2 to indicate that the session to be migrated of the upf#1 has been migrated to the upf#2, so that the upf#2 may upgrade from the backup UPF to the primary UPF according to the notification information #1, and traffic detours may be avoided, that is, user plane data is directly transmitted between the UE and the data network through the upf#2 without passing through the upf#1, and service short interruption caused by the upf#2 being upgraded to the primary UPF after detecting a failure of the upf#1 through heartbeat information is avoided, thereby improving continuity and stability of service.

In addition, if the upf#2 is updated from the standby UPF to the primary UPF, the notification information #2 is sent to the SMF, so that the SMF can timely learn that the upf#2 is updated to the primary UPF according to the notification information # 2.

In connection with fig. 2, fig. 4 shows a schematic flow chart of a method 400 for session migration provided by an embodiment of the present application. The method 400 shown in fig. 4 may include the steps of:

s401, the smf#1 receives the instruction#1 through the UI.

Instruction #1 is used to indicate migration of at least one session of UPF #1, and instruction #1 may refer to the description of the first instruction in S230 above.

S402, the smf#2 receives the instruction#2 through the UI.

Instruction #2 is used to indicate migration of at least one session of UPF #1, and instruction #2 may refer to the description of the first instruction in S230 above.

Note that, the instruction #1 and the instruction #2 may be the same or different, which is not limited in the embodiment of the present application. For example, if smf#1 is used to serve a UE subscribed to dnn#1 and smf#2 is used to serve a UE subscribed to dnn#2, then instruction#1 may include dnn#1 and instruction#2 may include dnn#2.

It should also be noted that, in the embodiment of the present application, S401 and S402 are performed by using the method 400 as an example, S401 may be an optional step, or S402 may be an optional step.

After the smf#1 receives the instruction#1, at least one session of the upf#1 is migrated according to the instruction of the instruction#1. Similarly, after the smf#2 receives the instruction#2, at least one session of the upf#1 is migrated according to the instruction of the instruction#2.

The following describes the procedure of session migration, taking as an example the migration of session #1 of UPF #1 by SMF #2, in conjunction with S403 to S410.

S403, the smf#2 transmits N4 session setup request information to the upf#2.

Accordingly, upf#2 receives N4 session setup request information from smf#2.

For more description of S403, reference may be made to S210 in method 200 above.

S404, upf#2 transmits N4 session setup response information to smf#2.

Accordingly, smf#2 receives N4 session setup response information from upf#2.

The N4 session establishment response information is used to instruct upf#2 to establish session#2 for ue#1.

Optionally, the method 400 further comprises S405.

S405, upf#2 publishes routing information #1.

S406, smf#2 sends namf_communication_n1n2 message forwarding information to AMF.

S407, the AMF sends the N2 PDU session resource modification request information to the RAN.

The N2 PDU session resource modification request information includes uplink N3 tunnel information of session #2.

For more description of S406 and S407, reference may be made to S220 in the method 200 above.

S408, the RAN sends the N2 PDU session resource modification response information to the AMF.

The N2 PDU session resource modification response information includes N2 SM information, which indicates that the RAN has established an uplink transmission path for session #2 between the RAN and UPF #2.

S409, the AMF sends nsmf_pdu session_update SM context request information to smf#2.

Accordingly, smf#2 receives nsmf_pdu session_update SM context request information from the AMF.

Nsmf_pdu session_update SM context request includes N2 SM information, and smf#2 may determine from the N2 SM information that the RAN has established an uplink transmission channel for session#2 between the RAN and upf#2.

Optionally, if the N4 link between smf#2 and upf#1 fails, the method 400 further includes S410.

S410, smf#2 transmits N4 session deletion information to upf#1.

Accordingly, upf#1 receives N4 session deletion information from smf#2.

For more description of S403 to S410, reference may be made to S303 to S310 in the method 300 above.

It should be noted that, based on the above steps S403 to S410, after the upf#2 establishes the session#2 for the ue#1 and the RAN establishes the uplink transmission channel between the RAN and the upf#2, the session#2 indicates that the session#1 has been migrated to the upf#2, and the session#2 may be understood as a session after the SMF migrates the session#1 to the upf#2.

Note that, if the instruction #2 received by the SMF #2 instructs migration of multiple sessions of the UPF #1, the SMF #2 sequentially migrates multiple sessions of the UPF #1 in the manner described in S403 to S410.

And the smf#1 migrates at least one session of the upf#1 in the manner described in S403 to S410 according to the instruction of the instruction # 1.

Optionally, after the migration of the session to be migrated for upf#1 by smf#1 and smf#2 is completed, the method 400 further includes S411 and S412.

S411, the smf#2 transmits heartbeat request information #a to the upf#1.

Accordingly, upf#1 receives heartbeat request information #a from smf#2.

Optionally, after receiving the heartbeat request information #a, the upf#1 may further send heartbeat response information #a to the smf#2.

S412, the smf#1 transmits heartbeat request information #b to the upf#1.

Accordingly, upf#1 receives heartbeat request information #b from smf#1.

Optionally, after receiving the heartbeat request information #b, the upf#1 may further send heartbeat response information #b to the smf#1.

The heartbeat-request information #1 and the heartbeat-request information #2 each include indication information #a (an example of second indication information) for indicating degradation of the UPF #1 to the backup UPF.

Accordingly, if the upf#1 has a primary-backup relationship with the upf#2 and the upf#1 is a primary UPF, after the upf#1 receives the indication information #a from the smf#1 and the smf#2, the upf#1 is downgraded from the primary UPF to the backup UPF according to the indication information #a. For example, the upf#1 issues route information #a, and route #a (an example of second route) indicated by route information #a (an example of second route) is lower in priority than route #b (an example of first route) corresponding to route information #b (an example of first route information) transmitted by the upf#2.

Optionally, after the upf#1 is downgraded from the primary UPF to the backup UPF, the method 400 further includes S413 and S414.

S413, the upf#1 transmits heartbeat request information #c to the smf#2.

Accordingly, smf#2 receives heartbeat request information #c from upf#1.

Optionally, after receiving the heartbeat request information #c, the smf#2 may further send heartbeat response information #c to the upf#1.

S414, upf#1 transmits heartbeat request information #d to smf#1.

Accordingly, the smf#1 receives heartbeat request information #d from the upf#1.

Optionally, after the smf#1 receives the heartbeat request information #d, the heartbeat response information #d may also be sent to the upf#1.

The heartbeat-request information #c and the heartbeat-request information #d each include notification information #a (an example of third notification information) indicating that the upf#1 has been downgraded from the primary UPF to the backup UPF.

Note that, if the upf#1 does not send the heartbeat request information #c, the smf#2 determines that the upf#1 is downgraded from the primary UPF to the backup UPF after migrating the session to be migrated of the upf#1 to the upf#2 according to the instruction # 2. If the UPF#1 does not send the heartbeat request information #D, the SMF#1 determines that the UPF#1 is downgraded from the primary UPF to the standby UPF after migrating the session to be migrated of the UPF#1 to the UPF#2 according to the instruction # 1.

Optionally, after the SMF (smf#1 and smf#2) migrates at least one session of upf#1 according to the received instruction, the method 400 may further include S415 and S416.

S415, the smf#2 transmits heartbeat request information #e to the upf#2.

Accordingly, upf#2 receives heartbeat request information #e from smf#2.

S416, smf#1 transmits heartbeat request information #f to upf#2.

Accordingly, upf#2 receives heartbeat request information #f from smf#1.

S415 to S416 may refer to S312 to S313 in the above method 300.

Optionally, after upf#2 is upgraded from the standby UPF to the primary UPF, the method 400 further includes S417 and S418.

S417, upf#2 transmits heartbeat request information #g to smf#2.

Accordingly, smf#2 receives heartbeat request information #g from upf#2.

S418, upf#2 transmits heartbeat request information #h to smf#1.

Accordingly, smf#1 receives heartbeat request information #h from upf#2.

S417 to S418 may refer to S314 to S315 in the above method 300.

Optionally, the method 400 may further include one or more of steps S419 to S429.

S419, the smf#1 receives the instruction#3 through the UI.

Instruction #3 is used to indicate migration of at least one session of UPF #2, and instruction #3 may refer to the description of the first instruction in S230 above.

S420, smf#2 receives instruction#4 through the UI.

Instruction #4 is used to indicate migration of at least one session of UPF #2, and instruction #4 may refer to the description of the first instruction in S230 above.

Note that, the instruction #3 and the instruction #4 may be the same or different, which is not limited in the embodiment of the present application. For example, if smf#1 is used to serve a UE subscribed to dnn#1 and smf#2 is used to serve a UE subscribed to dnn#2, instruction#3 may include dnn#1 and instruction#4 may include dnn#2.

It should also be noted that, in the embodiment of the present application, S419 and S420 are performed by using the method 400 as an example, S419 may be an optional step, or S420 may be an optional step.

Optionally, in the case where the SMFs (smf#1 and smf#2) determine to migrate the session of upf#2 according to the received instruction, the method 400 further includes S421 and S422.

S421, the smf#2 transmits heartbeat request information #i to the upf#1.

Accordingly, upf#1 receives heartbeat request information #i from smf#2.

Optionally, after receiving the heartbeat request information #i, the upf#1 may further send heartbeat response information #i to the smf#2.

S422, smf#1 transmits heartbeat request information #j to upf#1.

Accordingly, upf#1 receives heartbeat request information #j from smf#1.

Optionally, after receiving the heartbeat request information #j, the upf#1 may further send heartbeat response information #j to the smf#1.

The heartbeat request information #1 and the heartbeat request information #2 each include indication information #b for indicating that the UPF #1 is updated to the primary UPF.

Accordingly, if the upf#1 has a primary-backup relationship with the upf#2 and the upf#1 is a backup UPF, after the upf#1 receives the instruction information #b from the smf#1 and the smf#2, the upf#1 is updated from the backup UPF to the primary UPF according to the instruction information #b. For example, the upf#1 issues the route information #c, the route #c indicated by the route information #c has a higher priority than the route #b, the route #c indicates the node #2 to transmit the downstream packet having the destination address of the first address segment to the upf#1 for processing, and the node #2 is the last hop node of the upf#1.

Optionally, after upf#1 is upgraded from the standby UPF to the primary UPF, the method 400 further includes S423 and S424.

S423, upf#1 transmits heartbeat request information #k to smf#2.

Accordingly, smf#2 receives heartbeat request information #k from upf#1.

Optionally, after receiving the heartbeat request information #k, the smf#2 may further send heartbeat response information #k to the upf#1.

S424, upf#1 transmits heartbeat request information #l to smf#1.

Accordingly, the smf#1 receives heartbeat request information #l from the upf#1.

Optionally, after the smf#1 receives the heartbeat request information #l, the heartbeat response information #l may also be sent to the upf#1.

The heartbeat-request information #c and the heartbeat-request information #d each include notification information #b indicating that the upf#1 has been upgraded from the standby UPF to the primary UPF.

Optionally, in the case where the SMFs (smf#1 and smf#2) determine to migrate the session of upf#2 according to the received instruction, the method 400 may further include S425 and S426.

S425, smf#2 transmits heartbeat request information #m to upf#2.

Accordingly, upf#2 receives heartbeat request information #m from smf#2.

S426, the smf#1 transmits heartbeat request information #n to the upf#2.

Accordingly, upf#2 receives heartbeat request information #n from smf#1.

S425 to S426 may refer to S319 to S320 in the above method 300.

Optionally, after the upf#2 is downgraded from the primary UPF to the backup UPF, the method 400 further includes S427 and S428.

S427, upf#2 transmits heartbeat request information #o to smf#2.

Accordingly, smf#2 receives heartbeat request information #o from upf#2.

S428, the upf#2 transmits heartbeat request information #p to the smf#1.

Accordingly, smf#1 receives heartbeat request information #p from upf#2.

S427 to S428 may refer to S321 to S322 in the above method 300.

S429, smf#1 and/or smf#2 migrate at least one session of upf#2 to upf#1.

After the smf#1 receives the instruction #3, at least one session of the upf#2 is migrated to the upf#1 according to the instruction of the instruction # 3. Similarly, after the smf#2 receives the instruction#4, at least one session of the upf#2 is migrated to the upf#1 according to the instruction of the instruction#4.

S429 can refer to the descriptions of S403 to S410 above.

In the embodiment of the application, the SMF (smf#1 or smf#2) may migrate at least one session of the upf#1 to the upf#2 according to the received instruction, thereby avoiding a service interruption caused by the inability of the upf#1 to normally provide a service. Advantageous effects the description of the advantageous effects of the method shown in fig. 3 can be referred to, and will not be repeated

The application of the method provided in the embodiments of the present application in different scenarios is described below with reference to fig. 5 and 6.

Fig. 5 shows a schematic diagram of session migration in a load sharing disaster recovery scenario. As shown in (a) of fig. 5, in the process of successively migrating the session to be migrated of the upf#1 to the upf#2, the non-migrated session of the upf#1 performs user plane data transmission through the upf#1, and the session migrated to the upf#2 performs user plane data transmission through the upf#2. Further, as shown in (b) of fig. 5, if no online session is available on upf#1 after all the sessions to be migrated of upf#1 have been migrated to upf#2, the session migrated to upf#2 continues to perform user plane data transmission through upf#2. It will be appreciated that no impact on the traffic transmission will occur after no online session is made on UPF #1, even if UPF #1 is upgraded in software or hardware. Further, if upf#1 upgrades are completed, the session of upf#2 can be migrated to upf#1 again. As shown in (c) of fig. 5, in the process of successively migrating the session to be migrated of the upf#2 to the upf#1, the user plane data transmission is performed by the non-migrated session of the upf#2 through the upf#2, and the user plane data transmission is performed by the session migrated to the upf#1 through the upf#1.

Fig. 6 shows a schematic diagram of session migration in a primary and backup disaster recovery scenario. As shown in fig. 6 (a), in the process of successively migrating the session to be migrated of the upf#1 to the upf#2, the non-migrated session of the upf#1 performs user plane data transmission through the upf#1, and the session migrated to the upf#2 performs user plane data transmission through the upf#2 and the upf#1. Taking session #2 migrated to UPF #2 as an example, in a primary-backup disaster recovery scenario, the primary UPF (i.e., UPF # 1) publishes high-priority N6 routing information (e.g., routing information #4 in method 300 above), and the backup UPF (i.e., UPF # 2) publishes low-priority N6 routing information (e.g., routing information #3 in method 300 above). Further, when the upf#1 and the upf#2 are online at the same time, after the upf#2 receives an uplink packet of the session#2 in an uplink direction, the uplink packet is transmitted to the upf#1 through a generic routing encapsulation (generic routing encapsulation, GRE) tunnel between the upf#2 and the upf#1, and is transmitted to the DN by the upf#1; for the downlink direction, when the priority of the N6 routing information issued by the upf#1 is higher, the DN sends the downlink data packet of the session#2, the downlink data packet is sent to the upf#1 according to the N6 routing information issued by the upf#1, after the upf#1 receives the downlink data packet of the session#2, the downlink data packet is sent to the upf#2 according to the GRE tunnel, and then the upf#2 sends the downlink data packet to the UE. Further, as shown in fig. 6 (b), if all the sessions to be migrated of the upf#1 are migrated to the upf#2, the upf#2 may be upgraded from the standby UPF to the primary UPF, and then the sessions migrated to the upf#2 perform the user plane data transmission through the upf#2. Further, if the upf#1 is restored to the primary UPF after being restored to the normal state, the upf#2 is correspondingly downgraded to the backup UPF, and further, as shown in (c) of fig. 6, in the process that the session to be migrated of the upf#2 is migrated to the upf#1, the session migrated to the upf#1 performs the user plane data transmission through the upf#1, and the session not migrated to the upf#1 performs the user plane data transmission through the upf#1 and the upf#2.

The method provided in the embodiments of the present application is described in detail above in connection with fig. 2 to 6. The following describes in detail the communication device provided in the embodiment of the present application with reference to fig. 7 to 9. It should be understood that the descriptions of the apparatus embodiments and the descriptions of the method embodiments correspond to each other, and thus, descriptions of details not described may be referred to the above method embodiments, which are not repeated herein for brevity.

Fig. 7 is a schematic block diagram of a communication device 1000 provided in an embodiment of the present application. As shown in fig. 7, the communication apparatus 1000 may include: a transceiver unit 1010.

In one possible design, the communication device 1000 may be a session management network element in the above method embodiment, or may be a chip that implements the functions of the session management network element in the above method embodiment.

It is to be understood that the communication device 1000 may correspond to a session management network element in the method 200 of the embodiment of the application, or the communication device 1000 may correspond to an SMF in the method 300 or the method 400 of the embodiment of the application, the communication device 1000 may comprise means for performing a method performed by a session management network element in the method 200 of fig. 2, or the communication device 1000 may comprise means for performing a method performed by an SMF in the method 300 of fig. 3 or the method 400 of fig. 4. And, each unit in the communication device 1000 and the other operations and/or functions described above are respectively for implementing the corresponding flow of the method 200 in fig. 2, the method 300 in fig. 3, or the method 400 in fig. 4. 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.

In another possible design, the communication device 1000 may be the second user plane network element in the above method embodiment, or may be a chip for implementing the function of the second user plane network element in the above method embodiment.

It should be understood that the communication device 1000 may correspond to the second user plane network element in the method 200 of the embodiment of the present application, or the communication device 1000 may correspond to the upf#1/upf#2 in the method 300 or the method 400 of the embodiment of the present application, the communication device 1000 may include a unit for performing the method performed by the second user plane network element in the method 200 of fig. 2, or the communication device 1000 may include a unit for performing the method performed by the upf#1/upf#2 in the method 300 of fig. 3 or the method 400 of fig. 4. And, each unit in the communication device 1000 and the other operations and/or functions described above are respectively for implementing the corresponding flow of the method 200 in fig. 2, the method 300 in fig. 3, or the method 400 in fig. 4. 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.

In another possible design, the communication device 1000 may be the first user plane network element in the above method embodiment, or may be a chip for implementing the function of the first user plane network element in the above method embodiment.

It should be understood that the communication device 1000 may correspond to the first user plane network element in the method 200 of the embodiment of the present application, or the communication device 1000 may correspond to the upf#1/upf#2 in the method 300 or the method 400 of the embodiment of the present application, the communication device 1000 may include a unit for performing the method performed by the first user plane network element in the method 200 of fig. 2, or the communication device 1000 may include a unit for performing the method performed by the upf#1/upf#2 in the method 300 of fig. 3 or the method 400 of fig. 4. And, each unit in the communication device 1000 and the other operations and/or functions described above are respectively for implementing the corresponding flow of the method 200 in fig. 2, the method 300 in fig. 3, or the method 400 in fig. 4. 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 transceiving unit 1010 in the communication apparatus 1000 may correspond to the transceiver 2020 in the communication device 2000 shown in fig. 8.

Optionally, the communication device 1000 further comprises a processing unit 1020. The processing unit 1020 in the communication apparatus 1000 may correspond to the processor 2010 in the communication device 2000 illustrated in fig. 8.

It should also be appreciated that when the communication device 1000 is a chip, the chip includes a transceiver unit. Optionally, the chip may further comprise a processing unit. The receiving and transmitting unit can be an input and output circuit or a communication interface; the processing unit may be an integrated processor or microprocessor or an integrated circuit on the chip.

The transceiver 1010 is configured to perform a transceiver operation of a signal of the communication apparatus 1000, and the processing unit 1020 is configured to perform a processing operation of a signal of the communication apparatus 1000. Alternatively, the transceiver unit 1010 constitutes an acquisition unit, or the transceiver unit 1010 may be referred to as an acquisition unit. Optionally, the transceiver unit 1010 and the processing unit 1020 constitute an acquisition unit.

Optionally, the communication device 1000 further includes a storage unit 1030, where the storage unit 1030 is configured to store instructions.

Fig. 8 is a schematic block diagram of an apparatus 2000 provided by an embodiment of the present application. As shown in fig. 8, the apparatus 2000 includes: at least one processor 2010. The processor 2010 is coupled to the memory for executing instructions stored in the memory to perform the methods described in fig. 2, 3, or 4. Optionally, the apparatus 2000 further comprises a transceiver 2020, and the processor 2010 is coupled to the memory for executing instructions stored in the memory to control the transceiver 2020 to transmit signals and/or receive signals, e.g. the processor 2010 may control the transceiver 2020 to transmit IP addresses and/or receive IP addresses. Optionally, the apparatus 2000 further comprises a memory 2030 for storing instructions.

It will be appreciated that the processor 2020 and memory 2030 may be combined into one processing device, and that the processor 2020 is configured to execute program code stored in the memory 2030 to perform the functions described above. In particular implementations, the memory 2030 may also be integrated within the processor 2010 or separate from the processor 2010.

It is also to be understood that the transceiver 2020 may include a receiver (or receiver) and a transmitter (or transmitter). The transceiver 2020 may further include antennas, the number of which may be one or more. The transceiver 2020 may in turn be a communications interface or interface circuitry.

When the device 2000 is a chip, the chip includes a transceiver unit and a processing unit, where the transceiver unit may be an input/output circuit or a communication interface; the processing unit may be an integrated processor or microprocessor or an integrated circuit on the chip.

Fig. 9 is a schematic diagram of a chip system according to an embodiment of the present application. The chip system here can also be a system of circuits. The chip system 3000 shown in fig. 9 includes: logic 3010 for coupling to an input interface through which data (e.g., service access information) is transferred to perform the methods described in fig. 2, 3, or 4, and an input/output interface 3020.

The embodiment of the application also provides a processing device, which comprises a processor and an interface. The processor may be used to perform the methods of the method embodiments described above.

It should be understood that the processing means may be a chip. For example, the processing device may be a field programmable gate array (field programmable gate array, FPGA), an application specific integrated chip (application specific integrated circuit, ASIC), a system on chip (SoC), a central processing unit (central processor unit, CPU), a network processor (network processor, NP), a digital signal processing circuit (digital signal processor, DSP), a microcontroller (micro controller unit, MCU), a programmable controller (programmable logic device, PLD) or other integrated chip.

In implementation, the steps of the above method may be performed by integrated logic circuits of hardware in a processor or by instructions in the form of software. The steps of a method disclosed in connection with the embodiments of the present application may be embodied directly in a hardware processor for execution, or in a combination of hardware and software modules in the processor for execution. The software modules may be located in random access registers, flash memory, read-only memory, programmable read-only memory, or electrically erasable programmable memory, registers, etc. as well known in the art. The storage medium is located in a memory, and the processor reads the information in the memory and, in combination with its hardware, performs the steps of the above method. To avoid repetition, a detailed description is not provided herein.

It should be noted that the processor in the embodiments of the present application may be an integrated circuit chip with signal processing capability. In implementation, the steps of the above method embodiments may be implemented by integrated logic circuits of hardware in a processor or instructions in software form. The processor may be a general purpose processor, a Digital Signal Processor (DSP), an Application Specific Integrated Circuit (ASIC), a Field Programmable Gate Array (FPGA) or other programmable logic device, discrete gate or transistor logic, or discrete hardware components. The disclosed methods, steps, and logic blocks in the embodiments of the present application may be implemented or performed. A general purpose processor may be a microprocessor or the processor may be any conventional processor or the like.

It will be appreciated that the memory in embodiments of the present application may be either volatile memory or nonvolatile memory, or may include both volatile and nonvolatile memory. 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) which acts as an external cache.

According to the method provided by the embodiment of the application, the application further provides a computer program product, which comprises: computer program code for causing a computer to perform the method of the embodiments shown in fig. 2, 3 or 4 when the computer program code is run on the computer.

According to the method provided in the embodiments of the present application, there is further provided a computer readable medium storing a program code, which when run on a computer, causes the computer to perform the method in the embodiments shown in fig. 2, 3 or 4.

According to the method provided by the embodiment of the application, the application also provides a system, which comprises the session management network element, the first user plane network element and the second user plane network element.

In the above embodiments, it may be implemented in whole or in part by software, hardware, firmware, or any combination thereof, and when implemented in software, it 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 the computer instructions are loaded and executed on a computer, the processes or functions described in accordance with embodiments of the present application are produced in whole or in part. The computer instructions may be stored in a computer-readable storage medium or transmitted from one computer-readable information medium to another computer-readable storage medium. 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. The usable medium may be a magnetic medium (e.g., a floppy disk, a hard disk, a magnetic tape), an optical medium (e.g., a high-density digital video disc (digital video disc, DVD)), or a semiconductor medium (e.g., a Solid State Disk (SSD)), or the like.

In the several embodiments provided in this application, it should be understood that the disclosed systems, devices, and methods may be implemented in other manners. 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. Alternatively, the coupling or direct coupling or communication connection shown or discussed with each other may be an indirect coupling or communication connection via some interfaces, devices or units, which may be in electrical, mechanical or other forms.

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 method of session migration, comprising:

The method comprises the steps that a session management network element sends an address and downlink tunnel information of a terminal device to a first user plane network element, the terminal device is served by a second user plane network element, the downlink tunnel information and the address correspond to a first session, and the first session is established for the terminal device by the second user plane network element;

the session management network element sends uplink tunnel information corresponding to a second session to the access network device, the uplink tunnel information is used for establishing a transmission channel of the second session between the access network device and the first user plane network element, the second session is established by the first user plane network element for the terminal device, and the downlink tunnel information and the address are both corresponding to the second session.

2. The method according to claim 1, wherein the method further comprises:

and the session management network element receives the uplink tunnel information from the first user plane network element.

3. The method according to claim 1 or 2, characterized in that the method further comprises:

the session management network element receives first indication information from the second user plane network element or the first user plane network element, wherein the first indication information is used for indicating at least one session of the second user plane network element to be migrated, and the at least one session comprises the first session.

4. A method according to claim 3, wherein the first indication information comprises at least one data network name, DNN, the at least one session corresponding to the at least one DNN.

5. The method according to claim 1 or 2, characterized in that the method further comprises:

the session management network element receives a first instruction from a user, wherein the first instruction is used for indicating to migrate at least one session of the second user plane network element, and the at least one session comprises the first session.

6. The method of claim 5, wherein the first instruction comprises at least one DNN, the at least one session corresponding to the at least one DNN.

7. The method according to any of claims 1 to 6, wherein the second user plane network element fails.

8. The method according to any one of claims 1 to 7, further comprising:

the session management network element sends first notification information to the first user plane network element, wherein the first notification information is used for indicating that at least one session to be migrated of the second user plane network element has been migrated to the first user plane network element, and the at least one session to be migrated comprises the first session.

9. The method of claim 8, wherein the method further comprises:

the session management network element receives second notification information from the first user plane network element, where the second notification information is used to indicate that the first user plane network element has been upgraded from a standby user plane network element to a primary user plane network element.

10. The method according to any one of claims 1 to 6, further comprising:

and the session management network element sends third indication information to the second user plane network element, wherein the third indication information is used for indicating the second user plane network element to delete the session context of the first session.

11. A communication device is characterized by comprising a transceiver unit,

the receiving and transmitting unit is configured to send an address of a terminal device and downlink tunnel information to a first user plane network element, where the terminal device is served by a second user plane network element, and the downlink tunnel information and the address both correspond to a first session, where the first session is established by the second user plane network element for the terminal device;

the receiving and transmitting unit is further configured to send uplink tunnel information corresponding to a second session to an access network device, where the uplink tunnel information is used to establish a transmission channel of the second session between the access network device and the first user plane network element, the second session is established by the first user plane network element for the terminal device, and the downlink tunnel information and the address both correspond to the second session.

12. The communications apparatus of claim 11, wherein the transceiver unit is further configured to receive the uplink tunnel information from the first user plane network element.

13. The communication apparatus according to claim 11 or 12, wherein the transceiver unit is further configured to receive first indication information from the second user plane network element or the first user plane network element, the first indication information being configured to indicate migration of at least one session of the second user plane network element, the at least one session including the first session.

14. The communication apparatus according to claim 11 or 12, wherein the transceiving unit is further configured to receive a first instruction from a user, the first instruction being configured to instruct migration of at least one session of the second user plane network element, the at least one session comprising the first session.

15. The communication apparatus according to any of claims 11 to 14, wherein the transceiver unit is further configured to send first notification information to the first user plane network element, the first notification information being configured to indicate that at least one session to be migrated of the second user plane network element has been migrated to the first user plane network element, the at least one session to be migrated including the first session.

16. The communication apparatus according to any of claims 11 to 15, wherein the transceiver unit is further configured to send third indication information to the second user plane network element, the third indication information being configured to instruct the second user plane network element to delete a session context of the first session.

17. A communication device comprising at least one processor for coupling with a memory, reading and executing instructions in the memory to implement the method of any of claims 1 to 10.

18. The communication device of claim 17, further comprising the memory.

19. A computer readable storage medium, characterized in that the computer readable storage medium has stored thereon a computer program which, when executed, causes the method according to any of claims 1 to 10 to be performed.

20. A computer program product comprising instructions which, when run on a computer, cause the computer to perform the method of any of claims 1 to 10.

21. A system comprising a session management network element and a first user plane network element, the session management network element being configured to perform the method of any of claims 1 to 10.

22. A chip, comprising: a processor and an interface for calling from a memory and running a computer program stored in said memory, performing the method according to any of claims 1 to 10.