WO2024067633A1 - 切换方法及通信节点、存储介质 - Google Patents

切换方法及通信节点、存储介质 Download PDF

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Publication number
WO2024067633A1
WO2024067633A1 PCT/CN2023/121722 CN2023121722W WO2024067633A1 WO 2024067633 A1 WO2024067633 A1 WO 2024067633A1 CN 2023121722 W CN2023121722 W CN 2023121722W WO 2024067633 A1 WO2024067633 A1 WO 2024067633A1
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WIPO (PCT)
Prior art keywords
access network
network device
target access
network element
message
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PCT/CN2023/121722
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English (en)
French (fr)
Inventor
夏勇
刘俊羿
陈东华
侯利昌
詹亚军
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中兴通讯股份有限公司
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Publication of WO2024067633A1 publication Critical patent/WO2024067633A1/zh

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W36/00—Hand-off or reselection arrangements
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W36/00—Hand-off or reselection arrangements
    • H04W36/14—Reselecting a network or an air interface

Definitions

  • the present disclosure relates to the field of communication technology, and in particular to a switching method, a communication node, and a storage medium.
  • a terminal device moves from the coverage of a source access network device to the coverage of a target access network device, it is necessary to switch the terminal device from the source access network device to the target access network device so that the target access network device can provide services for the terminal device.
  • an embodiment of the present disclosure provides a switching method.
  • the switching method includes: in a switching preparation process in which a terminal device switches from a source access network device to a target access network device, the target access network device establishes a first transmission tunnel with a user plane network element; the target access network device receives and caches a first message through the first transmission tunnel, and the first message is a message to be sent to the terminal device.
  • the embodiment of the present disclosure provides a target access network device.
  • the target access network device includes: a first transmission tunnel establishment module, which is used to establish a first transmission tunnel with a user plane network element during a handover preparation process in which a terminal device switches from a source access network device to a target access network device; and a first message processing module, which is used to receive and cache a first message through the first transmission tunnel, where the first message is a message to be sent to the terminal device.
  • an embodiment of the present disclosure provides a switching method.
  • the switching method includes: in a switching preparation process in which a terminal device switches from a source access network device to a target access network device, a mobility management network element obtains tunnel information of the target access network device from the target access network device, and the tunnel information of the target access network device is used to establish a first transmission tunnel between the target access network device and a user plane network element; and the mobility management network element sends the tunnel information of the target access network device to a session management network element.
  • an embodiment of the present disclosure provides a mobility management network element.
  • the mobility management network element includes: a first acquisition module, used to acquire tunnel information of a target access network device from a target access network device during a handover preparation process in which a terminal device switches from a source access network device to a target access network device, wherein the tunnel information of the target access network device is used to establish a first transmission tunnel between the target access network device and a user plane function network element; and a first sending module, used to send the tunnel information of the target access network device to a session management network element.
  • an embodiment of the present disclosure provides a switching method.
  • the switching method includes: in a switching preparation process in which a terminal device switches from a source access network device to a target access network device, a session management network element obtains tunnel information of the target access network device from a mobility management network element, and the tunnel information of the target access network device is used to establish a first transmission tunnel between the target access network device and a user plane network element; and the session management network element sends the tunnel information of the target access network device to the user plane network element.
  • an embodiment of the present disclosure provides a session management network element.
  • the session management network element includes: a second acquisition module, used to acquire tunnel information of the target access network device from the mobility management network element during a handover preparation process in which a terminal device switches from a source access network device to a target access network device, wherein the tunnel information of the target access network device is used to establish a first transmission tunnel between the target access network device and a user plane function network element; and a second sending module, used to send the tunnel information of the target access network device to the user plane network element.
  • an embodiment of the present disclosure provides a switching method.
  • the switching method includes: in a switching preparation process in which a terminal device switches from a source access network device to a target access network device, a user plane network element establishes a first transmission tunnel with the target access network device; the user plane network element sends a first message to the target access network device through the first transmission tunnel, and the first message is a message to be sent to the terminal device.
  • an embodiment of the present disclosure provides a user plane network element.
  • the user plane network element includes: a second tunnel establishment module, which is used to establish a first transmission tunnel with a target access network device during a handover preparation process in which a terminal device switches from a source access network device to a target access network device;
  • the message processing module is used to send a first message to a target access network device through a first transmission tunnel, where the first message is a message to be sent to a terminal device.
  • an embodiment of the present disclosure provides a communication node, which includes: a memory and a processor; the memory and the processor are coupled; the memory is used to store a computer program; and the processor implements the switching method described in any of the above embodiments when executing the computer program.
  • an embodiment of the present disclosure provides a computer-readable storage medium having computer program instructions stored thereon, and when the computer program instructions are executed by a processor, the switching method described in any of the above embodiments is implemented.
  • an embodiment of the present disclosure provides a computer program product, which includes computer program instructions, and when the computer program instructions are executed by a processor, the switching method described in any of the above embodiments is implemented.
  • FIG1 is a schematic diagram of a communication system according to some embodiments.
  • FIG2 is a schematic diagram of another communication system according to some embodiments.
  • FIG3 is a schematic diagram of yet another communication system according to some embodiments.
  • FIG4 is a switching method according to some embodiments.
  • FIG5 is another switching method according to some embodiments.
  • FIG6 is another switching method according to some embodiments.
  • FIG7 is another switching method according to some embodiments.
  • FIG8 is another switching method according to some embodiments.
  • FIG9 is a schematic diagram of the structure of a target access network device according to some embodiments.
  • FIG10 is a schematic diagram of the structure of a mobility management network element according to some embodiments.
  • FIG11 is a schematic diagram of the structure of a session management network element according to some embodiments.
  • FIG12 is a schematic diagram of the structure of a user plane network element according to some embodiments.
  • FIG13 is a schematic diagram of the structure of a communication node according to some embodiments.
  • words such as “exemplarily” or “for example” are used to indicate examples, illustrations or descriptions. Any embodiment or design described as “exemplarily” or “for example” in the present disclosure should not be interpreted as being more preferred or more advantageous than other embodiments or designs. Specifically, the use of words such as “exemplarily” or “for example” is intended to present related concepts in a detailed manner.
  • the technical solution of the embodiment of the present disclosure can be applied to various communication systems.
  • GSM Global System For Mobile Communication
  • E-UTRA Evolved Universal Terrestrial Radio Access
  • UMTS Universal Mobile Telecommunications System
  • LTE Long Term Evolution
  • 5G fifth-generation
  • NR New Radio
  • the above communication system can also be applied to future-oriented communication technologies, and is applicable to the technical solutions provided by the embodiments of the present disclosure.
  • the evolved Node Base Station (eNB, also called LTE eNB) in the LTE system is connected to the 4G core network (e.g., Evolved Packet Core (EPC)) through the S1 interface, and different LTE eNBs are connected through the X2 interface.
  • LTE eNB1 and LTE eNB2 are connected through the X2 interface.
  • Figure 1 shows the network architecture of the LTE system, and the X2 interface supports direct transmission of data and signaling between two LTE eNBs.
  • the terminal equipment (User Equipment, UE) transmits data or signaling with the EPC through the LTE eNB to which it is connected.
  • UE User Equipment
  • NR gNB Next Generation Node B
  • NG-Core Next Generation Node B
  • Xn interface gNB1 and gNB2
  • Each NR gNB is connected to at least one terminal device in the NR system.
  • Figure 2 shows the network architecture of the NR system. In actual applications, the connection between the above-mentioned multiple devices is a wireless connection. In order to conveniently and intuitively represent the connection relationship between each device, solid lines are used in Figure 2.
  • the session management network element may also be referred to as a session management function network element
  • the user plane network element may also be referred to as a user plane function network element, which is not limited in the embodiment of the present disclosure.
  • the network element or entity corresponding to the gNB may be a radio access network (Radio Access Network, RAN), and the network elements included in the NG-Core network may be a session management function (Session Management Function, SMF) network element, a user plane function (User Plane Function, UPF) network element, a policy control function (Policy Control Function, PCF) network element, an application function (Application Function, AF) network element, and an authentication server function (Authentication Ser
  • the network element includes a unified data management (UDM) network element, a network exposure function (NEF) network element, a network repository function (NRF) network element, a data network (DN) network element, a security anchor function (SEAF) network element, or a network slice selection function (NSSF) network element.
  • UDM unified data management
  • NEF network exposure function
  • NRF network repository function
  • DN data network
  • SEAF security anchor function
  • NSSF network slice selection function
  • the mobility management network element may also be referred to as a mobility management function network element or an access and mobility management function network element, which is not limited in the disclosed embodiment.
  • the UE communicates with the AMF (Access And Mobility Management Function) network element through the N1 interface (referred to as N1).
  • the AMF network element communicates with the SMF network element through the N11 interface (referred to as N11).
  • the SMF network element communicates with one or more UPF network elements through the N4 interface (referred to as N4). Any two UPF network elements in one or more UPF network elements communicate through the N9 interface (referred to as N9).
  • the UPF network element communicates with the data network (Data Network, DN) through the N6 interface (referred to as N6).
  • Data Network, DN Data Network
  • the terminal device accesses the network through the access network device (for example, RAN device).
  • the access network device communicates with the AMF network element through the N2 interface (referred to as N2).
  • the SMF network element communicates with the PCF network element through the N7 interface (referred to as N7), and the PCF network element communicates with the AF network element through the N5 interface.
  • the access network equipment communicates with the UPF network element through the N3 interface (N3 for short). Any two or more AMF network elements communicate with each other through the N14 interface (N14 for short).
  • the SMF network element communicates with the UDM network element through the N10 interface (N10 for short).
  • the AMF network element communicates with the AUSF network element through the N12 interface (N12 for short).
  • the AUSF network element communicates with the UDM network element through the N13 interface (N13 for short).
  • the AMF network element communicates with the UDM network element through the N8 interface (N8 for short).
  • interface name between the network elements in FIG. 3 is only an example, and the interface name may be other names in implementation, which is not limited in the embodiments of the present disclosure.
  • AMF network element It belongs to the core network element and is mainly responsible for signaling processing, such as access control, mobility management, attachment and detachment, and gateway selection.
  • the AMF network element When providing services for a session in a terminal device, the AMF network element will provide control plane storage resources for the session to store the session identifier, the SMF network element identifier associated with the session identifier, etc.
  • Radio Access Network ((R)AN) equipment includes RAN equipment and AN equipment.
  • RAN equipment is mainly the wireless network equipment of the 3rd Generation Partnership Project (3GPP) network, and AN can be the access network equipment defined by non-3GPP.
  • RAN equipment mainly responsible for the wireless resource management, quality of service (QoS) management, data compression and encryption and other functions on the air interface side.
  • the access network equipment may include various forms of base stations, such as macro base stations, micro base stations (also known as small stations), relay stations, access points, etc.
  • the names of devices with base station functions may be different. For example, in the fifth generation system, the device with base station function is called RAN.
  • the device with base station function is called evolved Node B (eNB or eNodeB).
  • the device with base station function is called Node B, etc.
  • AN equipment allows the terminal equipment and the 3GPP core network to interconnect and communicate using non-3GPP technologies.
  • Non-3GPP technologies include: Wireless Fidelity (Wi-Fi), World Wide Interoperability for Microwave Access (WiMAX), and Code Division Multiple Access (CDMA) networks.
  • SMF network element responsible for user plane function network element selection, user plane function network element redirection, Internet Protocol (IP) address allocation, bearer establishment, modification and release, and quality of service (QoS) control.
  • IP Internet Protocol
  • UPF network element responsible for forwarding and receiving user data in terminal devices. It can receive user data from the data network and transmit it to the terminal device through the access network device. The UPF network element can also receive user data from the terminal device through the access network device and forward the user data to the data network.
  • the transmission resources and scheduling functions in the UPF network element that provide services to the terminal device are managed and controlled by the SMF network element.
  • PCF network element mainly supports providing a unified policy framework to control network behavior, provides policy rules for control layer network functions, and is responsible for obtaining user contract information related to policy decisions.
  • AUSF network element mainly provides authentication and authorization functions.
  • NEF network element mainly supports the secure interaction between 3GPP network and third-party applications. NEF network element can safely open network capabilities and events to third parties to enhance or improve the quality of application services. 3GPP network can also securely obtain relevant data from third parties to enhance the network's intelligent decision-making. At the same time, the NEF network element supports the recovery of structured data from a unified database or the storage of structured data in a unified database.
  • AF network element mainly supports interaction with the 3GPP core network to provide services, such as influencing data routing decisions, policy control functions, or providing some third-party services to the network side.
  • the terminal device in the embodiment of the present disclosure may be a device that provides voice and/or data connectivity to a user, a handheld device with a wireless connection function, or other processing devices connected to a wireless modem.
  • the wireless terminal device may communicate with one or more core networks via the RAN.
  • the wireless terminal device may be a handheld terminal device, a laptop, a subscriber unit, a cellular phone, a smart phone, a wireless data card, a personal digital assistant (PDA) computer, a tablet computer, a wireless modem, a handheld device, a laptop computer, a cordless phone or a wireless local loop (WLL) station, a machine type communication (MTC) terminal device or other device that can access the network.
  • the terminal device and the access network device communicate with each other using a certain air interface technology (for example, 3GPP access technology or non-3GPP access technology).
  • a base station can generally cover one or more cells. Each cell has a certain coverage area, which is relatively fixed. If the terminal device leaves the serving cell and enters another cell during movement, and the other cell and the aforementioned serving cell are managed by different base stations (for example, the aforementioned serving cell belongs to source base station, and the other cell belongs to the target base station), the terminal device needs to switch from the source base station to the target base station under the control of the current mobile management technology.
  • the fifth generation mobile communication technology switching process defines a switching process based on an Xn interface and a switching process based on an N2 interface.
  • the Xn interface is an interface between two access network devices.
  • the switching process based on the Xn interface can be understood as when the source radio access network (Source Radio Access Network, S-RAN) device determines that the terminal device is switching access network device, the S-RAN device sends a switching request to the target radio access network (Target Radio Access Network, T-RAN) device; when the S-RAN device determines that the T-RAN device agrees to switch the terminal device to the T-RAN device, the S-RAN device initiates a switching process to the terminal device, for example, the S-RAN device sends a switching command to the terminal device to switch the terminal device to the T-RAN device.
  • S-RAN Source Radio Access Network
  • T-RAN Target Radio Access Network
  • N2 is the interface between the access network device and the AMF network element.
  • the switching process based on N2 can be understood as follows: when the S-RAN device determines that the terminal device is switching the access network device, the S-RAN device sends a switching request to the S-AMF network element, and the S-AMF network element is the AMF network element connected to the S-RAN device; after the S-AMF network element selects the T-AMF network element, the S-AMF network element sends a switching request to the T-AMF network element, and the T-AMF network element sends the switching request to the T-RAN device, and the T-AMF network element is the AMF network element connected to the T-RAN device; when the T-AMF network element receives the switching request confirmation from the T-RAN device, it sends the switching request confirmation to the S-RAN device through the S-SMF network element.
  • the S-RAN device When the S-RAN device agrees to switch the terminal device to the T-RAN device, the S-RAN device initiates a switching process to the terminal device, such as sending a switching command to the terminal device to switch the terminal device to the T-RAN device.
  • the T-AMF network element and the S-AMF network element can be the same AMF network element.
  • the T-RAN device cannot directly obtain the downlink message sent to the terminal device from the user plane functional network element. Therefore, during the switching process, the T-RAN device needs to obtain the downlink message sent to the terminal device from the S-RAN device, or wait for the transmission tunnel to be established with the user plane to obtain the downlink message sent to the terminal device.
  • the T-RAN device may not be able to immediately send the downlink message to the terminal device because it has not received the downlink message sent to the terminal device, which in turn causes a large switching delay and reduces the reliability of communication.
  • the embodiment of the present disclosure provides a switching method, which pre-establishes a first transmission tunnel between the target access network device and the user plane functional network element during the switching of the access network device, so that before the switching is completed, the target access network device can directly obtain the downlink message sent to the terminal device from the user plane functional network element.
  • the target access network device can directly obtain the downlink message sent to the terminal device according to the established first transmission tunnel, without waiting for the downlink message sent to the terminal device from the source access network device, or waiting to establish a transmission tunnel with the user plane before obtaining the downlink message sent to the terminal device, thereby reducing the transmission delay of the message when switching the access network device and improving the reliability of communication.
  • Fig. 4 is a switching method according to some embodiments. Referring to Fig. 4, the switching method provided by the embodiment of the present disclosure includes the following steps.
  • the target access network device establishes a first transmission tunnel with a user plane functional network element.
  • the source access network device is the access network device that the terminal device accesses before the handover
  • the target access network device is the access network device that the terminal device accesses when the handover is completed.
  • the handover preparation process is the process of pre-establishing the first transmission tunnel.
  • the first transmission tunnel may be an N3 tunnel between the user plane functional network element and the target access network device, which is used to transmit downlink messages to be sent to the terminal device between the user plane functional network element and the target access network device when executing the handover process between the terminal device and the access network device.
  • the method for establishing the transmission tunnel may refer to the embodiment corresponding to FIG. 6 below.
  • the second transmission tunnel may be an N3 tunnel between the user plane function network element and the source access network device, which is used to transmit downlink messages sent between the user plane function network element and the source access network device to the terminal device when executing the handover process between access network devices of the terminal device.
  • the user plane functional network element sends a first message to the target access network device through a first transmission tunnel.
  • the first message is a message to be sent to the terminal device.
  • the user plane function network element in S102 when no user plane function network element switching occurs on the core network side, the user plane function network element in S102 sends a first message to the source access network device through the second transmission tunnel.
  • the user plane function network element mentioned in S102 is a target user plane function network element.
  • the target user plane function network element can obtain the first message from the source user plane function network element.
  • the source user plane function network element also sends the first message to the source access network device through the second transmission tunnel.
  • the source access network device receives the first message. It is understandable that the first message received by the source access network device and the first message received by the target access network device are the same message. It is understandable that the second transmission tunnel is pre-established by the source access network device and the user plane function network element.
  • the first message carries a redundant transmission identifier to indicate that the first message is transmitted by the user plane functional network element to the source access network device and the target access network device respectively in a redundant transmission manner.
  • the target access network device receives and buffers the first message through the first transmission tunnel.
  • the first message carries a redundant transmission identifier.
  • the redundant transmission identifier is used for marking the message obtained by redundantly transmitting the message to the source access network device and the target access network device simultaneously by the user plane functional network element; it can be understood that for the first message marked with the redundant transmission identifier, the same first message exists in the target access network device and the source access network device. It can be understood that there is no limitation on the number of bits of the redundant transmission identifier of the embodiment of the present disclosure, and the position in the first message.
  • the redundant transmission identifier can be marked by the user plane functional network element.
  • the first message may include one or more downlink messages to be sent by the user plane functional network element to the terminal device.
  • the first message is the downlink message to be sent to the terminal device.
  • the first message may include a batch or multiple batches of messages obtained by batch processing the multiple downlink messages to be sent to the terminal device.
  • the interface (such as the above-mentioned Xn interface or the above-mentioned N2 interface) on which the target access network device receives the first message can be determined by the network in which the target access network device is located. For example, if there is an Xn interface between the target access network device and the source access network device, the target access network device receives the first message through the Xn interface; if there is an N2 interface between the target access network device and the mobility management function network element, the target access network device receives the first message through the N2 interface.
  • the embodiment shown in FIG4 pre-establishes a first transmission tunnel between the target access network device and the user plane functional network element during the handover preparation process when the terminal device switches from the source access network device to the target access network device, so that before the handover is completed, the target access network device can directly obtain the downlink message sent to the terminal device from the user plane functional network element.
  • the target access network device can always obtain the downlink message sent to the terminal device according to the established first transmission tunnel, without waiting for the downlink message sent to the terminal device from the source access network device, or waiting to establish a transmission tunnel with the user plane to obtain the downlink message sent to the terminal device, thereby reducing the transmission delay of the message when switching the access network device and improving the reliability of communication.
  • the method further includes S104 to S105 .
  • the target access network device establishes a communication connection with the terminal device.
  • the target access network device sends a first message to the terminal device through the communication connection between the target access network device and the terminal device.
  • the target access network device sends the first message cached by itself to the terminal device, that is, sends all the messages cached by itself to be sent to the terminal device to the terminal device.
  • the target access network device sends a first message to the terminal device through a communication connection with the terminal device, for example, it can be implemented as follows: the target access network device excludes the second message from the first message to obtain a third message.
  • the second message is a message that the source access network device has successfully sent to the terminal device in the first message received by the source access network device through the second transmission tunnel; the target access network device sends the third message to the terminal device through a communication connection with the terminal device, that is, sends part of the message in the first message (such as a message that is not sent to the terminal device) to the terminal device.
  • the target access network device excludes the second message from the first message to obtain the third message, for example, it can be implemented as follows: the target access network device receives the sequence number of the second message from the source access network device; the target access network device excludes the second message from the first message based on the sequence number of the second message to obtain the third message.
  • the target access network device can exclude the messages that have been received by the terminal device from the cached first messages, avoid repeated sending, and improve the efficiency and reliability of communication.
  • the target access network device after S104 or S105, the target access network device has established a communication connection with the terminal device, and the user plane functional network element may no longer transmit messages sent to the terminal device to the source access network device, so redundant transmission can be terminated to save the overhead of message transmission and improve communication efficiency.
  • the user plane function network element may also receive the indication information sent by the session management function network element for indicating to stop the redundant transmission, and based on the indication information, send the fourth message that does not carry the redundant transmission identifier to the target access network device through the first transmission tunnel.
  • the target access network device may also receive the fourth message that does not carry the redundant transmission identifier through the first transmission tunnel. It can be understood that the fourth message is a downlink message sent to the terminal device that does not include the redundant transmission identifier.
  • the target access network device may also send the fourth message to the terminal device.
  • the first transmission tunnel is established in the following manner.
  • the target access network device sends tunnel information of the target access network device to the mobility management function network element.
  • the tunnel information of the target access network device is used to establish a first transmission tunnel between the target access network device and the user plane function network element.
  • the tunnel information of the target access network device includes one or more of the following information: the identity of the target access network device, application timestamp, tunnel type, tunnel bandwidth, tunnel address, and tunnel priority; the identity of the target access network device is used to identify the target access network device.
  • the target access network device receives a handover request message sent by the mobility management function network element or the source access network device, the above S201 is executed.
  • the handover request message is used to request to handover the terminal device to the target access network device.
  • the target access network device receives the handover request information sent by the source access network device, and sends the tunnel information of the target access network device to the mobility management function network element.
  • the target access network device receives the handover request information sent by the mobility management function network element, and sends the tunnel information of the target access network device to the mobility management function network element.
  • the above S201 may be implemented as follows: the target access network device sends path pre-switching request information to the mobility management function network element.
  • the path pre-switching request information includes tunnel information of the target access network device.
  • the mobility management function network element obtains tunnel information of the target access network device from the target access network device.
  • the above S202 may be implemented as follows: the mobility management function network element obtains the path prediction sent by the target access network device. Switching request information, based on the path pre-switching request information, obtaining the tunnel information of the target access network device.
  • the mobility management function network element sends the tunnel information of the target access network device to the session management function network element.
  • S203 is implemented as, for example: the mobility management function network element sends a request (Nsmf_PDUSession_UpdateSMContext Request) message for updating the PDU session context to the session management function network element, and the Nsmf_PDUSession_UpdateSMContext Request message includes tunnel information of the target access network device.
  • the PDU session context includes: the IP (Internet Protocol) address used by the PDU session, the access point name (APN), the session management function network element address, and the user plane function network element address information.
  • IP Internet Protocol
  • API access point name
  • API session management function network element address
  • the session management function network element obtains tunnel information of the target access network device from the mobility management function network element.
  • the session management function network element obtains the Nsmf_PDUSession_UpdateSMContext Request information sent by the mobility management function network element, and obtains the tunnel information of the target access network device based on the Nsmf_PDUSession_UpdateSMContext Request information.
  • the session management function network element sends the tunnel information of the target access network device to the user plane function network element.
  • the above S205 is implemented as: the session management function network element sends an N4 session modification request (N4session modify request) to the user plane function network element.
  • the above N4 session modification request includes tunnel information of the target access network device.
  • the user plane function network element obtains tunnel information of the target access network device from the session management function network element.
  • the above S206 is implemented as follows: the user plane function network element obtains the N4 session modification request sent by the session management function network element, and obtains the tunnel information of the target access network device based on the N4 session modification request.
  • the user plane functional network element allocates a transmission tunnel to the target access network device based on the tunnel information of the target access network device.
  • the user plane function network element sends the response information of S205 to the session management function network element.
  • the above S207 is implemented, for example, as follows: the user plane function network element sends N4 session modification request response information to the session management function network element.
  • the session management function network element After receiving the above-mentioned S205 response information sent by the user plane function network element, the session management function network element sends the above-mentioned S203 response information to the mobility management function network element.
  • S208 is implemented as follows: after receiving the above-mentioned S205 response information sent by the user plane function network element, the session management function network element sends the above-mentioned response information of the request to update the PDU session context to the mobility management function network element.
  • the first transmission tunnel is established.
  • the mobility management function network element After receiving the above-mentioned S203 response information sent by the session management function network element, the mobility management function network element sends the above-mentioned S201 response information to the target access network device.
  • the above S209 is implemented as follows: after receiving the above S203 response information sent by the session management function network element, the mobility management function network element sends response information of the path pre-switching request information to the target access network device.
  • S207 to S209 are response information of S205, S203, and S201 respectively, and reference may be made to the contents in some technologies.
  • the above S207 to S209 are not shown in FIG6 .
  • the terminal device receives the measurement control (Measurement Control) command from the source access network device, and sends a measurement report (Measurement Reports) to the source access network device.
  • Measurement Control Measurement Control
  • Measurement Reports a measurement report
  • the source access network device may be a 5G gNB, NR or other RAN device, which is not limited in the embodiments of the present disclosure.
  • the terminal device can access the first network through a source access network device, and the source access network device is a RAN device to which a serving cell of the terminal device belongs; the terminal device can periodically measure the signal quality of the serving cell of the terminal device and the signal quality of the neighboring cell of the terminal device.
  • the above-mentioned first network can be a 4G core (Evolved Packet Core, EPC) network or a 5G core (Next Generation Core, NG-Core) network.
  • the terminal device before the terminal device sends a measurement report to the source access network device, the terminal device receives a measurement control (Measurement Control) command sent by the source access network device for establishing the measurement, and establishes the corresponding measurement according to the received measurement control command. Further, the terminal device sends a measurement report to the source access network device based on the established measurement. If the terminal device fails to successfully establish the measurement due to its own equipment failure or communication failure, etc., it sends measurement failure information (e.g., Measurement Control Failure Information) to the source access network device. Alternatively, if the terminal device successfully establishes the measurement and obtains the measurement result, it sends a measurement report including the measurement result to the source access network device.
  • Measurement Control Measurement Control
  • the above-mentioned measurement report is used to indicate the signal quality of the terminal device.
  • the measurement results in the above-mentioned measurement report may include: the signal quality of the RAN device to which the serving cell of the terminal device belongs and the signal quality of the RAN device to which the neighboring cell of the terminal device belongs.
  • the above-mentioned signal quality may include reference signal receiving power (Reference Signal Receiving Power, RSRP).
  • RSRP Reference Signal Receiving Power
  • RSRQ Reference Signal Receiving Quality
  • the signal quality may include RSRP and RSRQ. It will be understood that the above-mentioned signal quality is only an example and the present disclosure is not limited to this.
  • the above-mentioned sending of measurement reports to the source access network device can be implemented, for example, as follows: the terminal device periodically sends measurement reports to the source access network device; or, the terminal device sends measurement reports to the source access network device when triggered by an event.
  • the above event triggers include but are not limited to one or more of the following: the terminal device determines that the signal quality of the serving cell is less than or equal to the first threshold or the signal quality of the neighboring cell is greater than or equal to the second threshold; or, within a preset duration, the terminal device detects that the signal quality of the serving cell is continuously lower than the signal quality of the neighboring cell; or, the terminal device receives a measurement control command sent by the source access network device; or, the transmitter address (TA) to which the terminal device belongs changes.
  • the embodiments of the present disclosure do not limit the first threshold, the second threshold, and the preset duration, and can be set as required.
  • the source access network device determines to perform handover (Handover decision) based on the measurement report information.
  • the source access network device determines whether it is necessary to switch the RAN device for the terminal device based on the measurement report information reported by the terminal device.
  • a RAN device is determined as the target access network device for the terminal device to switch based on the radio resource management information. For example, the source access network device may select a RAN device belonging to a neighboring cell whose signal quality is greater than or equal to a second threshold as the target access network device for the terminal device to switch based on the signal quality of one or more neighboring cells.
  • the source access network device sends a handover request message (Handover Request message) to the target access network device.
  • Handover Request message a handover request message
  • the target access network device receives the switching request message from the source access network device.
  • the switching request message may be used to request that the terminal device be switched to the target access network device.
  • the source access network device sends the switching request message to the target access network device via the Xn interface.
  • the handover request information includes one or more of the following information: a handover reason, a target cell identifier, a handover restriction list, a temporary identifier corresponding to the terminal device, and a network slice number corresponding to one or more or all network slices selected by the terminal device.
  • Slice identification wireless bearer information that needs to be established corresponding to one or more or all network slices selected by the terminal device, session information that needs to be established corresponding to one or more or all network slices selected by the terminal device, and flow information that needs to be established corresponding to one or more or all network slices selected by the terminal device.
  • the switching reason is used to indicate the reason for the switching.
  • the target cell identifier is used to uniquely indicate the identifier of the target cell.
  • the switching restriction list includes the serving public land mobile network (PLMN), equivalent PLMN, and prohibited service areas.
  • PLMN public land mobile network
  • the temporary identifier corresponding to the terminal device is used by the CN device to search for the saved terminal device context (UE context).
  • the radio bearer information includes, but is not limited to, one or more of the following: radio bearer identifier, radio bearer-level QoS parameters, tunnel endpoint, or user-plane security information corresponding to the radio bearer.
  • Session information includes, but is not limited to, one or more of the following: session identifier, session-level QoS parameters, tunnel endpoint, or user-plane security information corresponding to the session.
  • Flow information includes, but is not limited to, one or more of the following: flow identifier, flow-level QoS parameters, tunnel endpoint, or user-plane security information corresponding to the flow.
  • switching request information is only an example and may also include other information (such as downlink SN status (DL SN Status) information), which is not limited in the present disclosure.
  • DL SN Status downlink SN Status
  • the target access network device performs admission control (Admission Control).
  • the target access network device executing admission control indicates that the target access network device has prepared resources and is ready for pre-switching.
  • S304 is implemented as follows: in response to the switching request message, if the target access network device allows network switching, the target access network device performs admission control.
  • the target access network device performs access control on the terminal device based on its own support capabilities, resource conditions, and remapping policy information for the stream/session/radio bearer of the network slice in which the terminal device communicates with the source access network device.
  • the target access network device determines that it can meet the support capabilities, resource conditions, and remapping policy information of the stream/session/radio bearer of the network slice communicated by the source access network device. Otherwise, the target access network device sends an indication message to the source access network device to refuse to switch the terminal device to the target access network device. For example, if the target access network device determines that it can meet the wireless resource requirements required by the terminal device, the target access network device performs admission control on the terminal device.
  • the target access network device sends path pre-switching request information to the mobility management function network element in response to the switching request information.
  • the path pre-switching request information includes tunnel information of the target access network device.
  • the tunnel information of the target access network device includes one or more of the following information: the identity of the target access network device, application timestamp, tunnel type, tunnel bandwidth, tunnel address, and tunnel priority; the identity of the target access network device is used to identify the target access network device.
  • the mobility management function network element receives path pre-switching request information from the target access network device.
  • the mobility management function network element obtains tunnel information of the target access network device based on the path pre-switching request information.
  • the mobility management function network element sends the tunnel information of the target access network device to the session management function network element.
  • S307 is implemented as, for example: the mobility management function network element sends a request (Nsmf_PDUSession_UpdateSMContext Request) message for updating the PDU session context to the session management function network element, and the Nsmf_PDUSession_UpdateSMContext Request message includes tunnel information of the target access network device.
  • the PDU session context includes: the IP (Internet Protocol) address used by the PDU session, the access point name (APN), the session management function network element address, and the user plane function network element address information.
  • IP Internet Protocol
  • API access point name
  • API session management function network element address
  • the session management function network element obtains tunnel information of the target access network device from the mobility management function network element.
  • S308 is implemented as follows: the session management function network element obtains the Nsmf_PDUSession_UpdateSMContext Request information sent by the mobility management function, and based on the Nsmf_PDUSession_UpdateSMContext Request information, obtains the tunnel information of the target access network device.
  • the session management function network element sends the tunnel information of the target access network device to the user plane function network element.
  • the above S309 is implemented as: the session management function network element sends an N4 session modification request (N4 Session Modify Request) to the user plane function network element.
  • N4 Session Modify Request N4 Session Modify Request
  • the N4 session modification request includes the tunnel information of the target access network device.
  • the N4 session modification request is used to establish a connection between the session management function network element and the user plane function network element.
  • the session management function network element further sends a redundant transmission rule to the user plane function network element, the redundant transmission rule is used to configure the user plane function network element to send the first message to the target access network device and the source access network device.
  • the first message has been described in detail above and will not be repeated here.
  • the user plane function network element obtains tunnel information of the target access network device from the session management function network element.
  • the user plane functional network element installs a downlink redundant forwarder so that after the first transmission tunnel is established, the user plane functional network element can simultaneously send the same first message to the source access network device and the target access network device.
  • the first message further includes a redundant transmission identifier.
  • the user plane function network element sends the response information of S309 to the session management function network element.
  • S311 is implemented, for example, as follows: the user plane function network element sends N4 session modification request response information to the session management function network element.
  • S312 In response to the response information of S309 sent by the user plane function network element, the session management function network element sends the response information of S307 to the mobility management function network element.
  • S312 is implemented as follows: after receiving the above-mentioned S309 response information sent by the user plane function network element, the session management function network element sends the above-mentioned response information of the request to update the PDU session context to the mobility management function network element.
  • the mobility management function network element In response to the response information of S307 sent by the session management function network element, the mobility management function network element sends the response information of S305 to the target access network device.
  • S313 is implemented as follows: in response to the response information of S307 sent by the session management function network element, the mobility management function network element sends a response information of the path pre-switching request information to the target access network device. It can be understood that after S313, the first transmission tunnel is established.
  • the user plane function network element sends the first message to the target access network device through the first transmission tunnel.
  • the target access network device may also cache the first message.
  • the user plane function network element After the first transmission tunnel is established, the user plane function network element also sends the same first message to the source access network device based on the second transmission tunnel. It can be understood that the second transmission tunnel is pre-established between the source access network device and the user plane function network element.
  • the target access network device After the first transmission tunnel is established, the target access network device sends a handover request confirmation message (Handover Request Acknowledge message) to the source access network device.
  • a handover request confirmation message (Handover Request Acknowledge message)
  • S314 is a response to S303.
  • the switching request confirmation message can be used to indicate that the target access network device allows the terminal device to be switched to the target access network device.
  • the source access network device In response to the switching request confirmation message, notifies the terminal device to prepare to switch the access network device.
  • the source access network device sends status transfer information (SN STATUS TRANSFER information) to the target access network device.
  • the state transfer information includes a sequence number of a second message of the source access network device, so that the target access network device can learn about the message that the source access network device has sent.
  • the second message is a message that the source access network device has successfully sent to the terminal device in the first message received by the source access network device through the second transmission tunnel.
  • the target access network device receives the state transfer information sent by the source access network device.
  • the target access network device can exclude the message that the terminal device has received from the cached first message based on the sequence number to avoid repeated transmission and improve the efficiency and reliability of communication.
  • the target access network device can already send the first message from the first transmission tunnel to the terminal device.
  • the target access network device sends first switching completion confirmation information to the mobility management function network element.
  • the first switching completion confirmation information is used to indicate that the path switching on the terminal device side is completed.
  • the first switching completion confirmation information is also used to request to end redundant transmission.
  • the first switching completion confirmation information is also used to request the release of resources of the source access network device used to transmit downlink messages of the terminal device.
  • the mobility management function network element After receiving the first switching completion confirmation information, the mobility management function network element sends the first switching completion confirmation information to the session management function network element.
  • the above S319 is implemented as follows: after the mobility management function network element receives the first switching completion confirmation information, it sends a request message for updating the PDU session context to the session management function network element, and the request message for updating the PDU session context includes the above first switching completion confirmation information.
  • the session management function network element After receiving the first switching completion confirmation information, the session management function network element sends the first switching completion confirmation information to the user plane function network element.
  • the above S320 is implemented as follows: after receiving the first switching completion confirmation information, the session management function network element sends an N4 session modification request to the user plane function network element, and the N4 session modification request includes the first switching completion confirmation information.
  • the user plane function network element After receiving the first switching completion confirmation information, the user plane function network element sends a second switching completion confirmation information to the session management function network element.
  • the above S321 is implemented as follows: after receiving the first switching completion confirmation message, the user plane function network element sends an N4 session modification request response message to the session management function network element, and the N4 session modification request response message includes a second switching completion confirmation message.
  • the second handover completion confirmation message is used to indicate the release of resources of the source access network device for transmitting downlink messages of the terminal device.
  • the second handover completion confirmation message can be used to indicate the release of the second transmission tunnel between the source access network device and the user plane functional network element, or the release of the first message including the redundant transmission identifier that has not been sent in the source access network device, etc.
  • the redundant transmission is ended, and a fourth message without a redundant transmission identifier is sent to the target access network device through the first transmission tunnel.
  • the session management function network element After receiving the second switching completion confirmation information, the session management function network element sends the second switching completion confirmation information to the mobility management function network element.
  • the above S322 is implemented as follows: after the session management function network element receives the second switching completion confirmation message, it sends a response message of the request to update the PDU session context to the mobility management function network element, and the response message of the request to update the PDU session context includes the second switching completion confirmation message.
  • the mobility management function network element After receiving the second switching completion confirmation information, the mobility management function network element sends the second switching completion confirmation information to the target access network device.
  • the target access network device After receiving the switching completion confirmation message, the target access network device sends a second switching completion confirmation message to the source access network device.
  • the source access network device releases its own resources and no longer performs message transmission with the user plane functional network element as the access network device of the terminal device.
  • the embodiment shown in Figure 7 above is based on the example that the target access network device and the source access network device belong to the same AMF network element.
  • the source access network device and the target access network device may belong to different AMF network elements, and the present disclosure does not impose any restrictions on this.
  • Fig. 8 shows another switching method provided by an embodiment of the present disclosure. The following description is made by taking the switching based on the N2 interface as an example, referring to Fig. 8, for example, as follows.
  • a source access network device sends a handover request message to a mobility management function network element.
  • the switching request message may include the identifier of the target access network device, the source to target container (e.g., Target To Source Transparent Container), the session management (SM) N2 information list, the PDU session identifier, and the system internal switching indication.
  • the source to target container e.g., Target To Source Transparent Container
  • the session management (SM) N2 information list e.g., the PDU session identifier
  • the system internal switching indication e.g., the identifier of the target access network device, the source to target container (e.g., Target To Source Transparent Container), the session management (SM) N2 information list, the PDU session identifier, and the system internal switching indication.
  • SM session management
  • the identifier of the target access network device is used to identify the target access network device.
  • the source-to-target container includes the access network information used by the target access network device.
  • the information carried in the source-to-target container is not perceived by the core network.
  • the source-to-target container can be understood as a container sent by the source access network device to the target access network device.
  • the detailed content in the container is not identified and processed by the intermediate network element and can be directly transmitted to the target access network device.
  • the target access network device can parse the content after receiving the source-to-target container.
  • the SM N2 information list includes an indication of whether a direct forwarding path is available.
  • the system internal switching indication is used to indicate that the switching is a switching within 5G.
  • the source access network device determines to initiate the switching process of N2.
  • the process can refer to the process of determining to execute the switching shown in S301 to S302 above, which is not described in detail here.
  • the mobility management function network element In response to the handover request message, the mobility management function network element sends a request message for updating the PDU session context to the session management function network element.
  • the request message of the PDU session context may include an SMN2 information list, which is used to indicate whether a direct forwarding path is available.
  • the mobility management function network element can provide services for the terminal device, the above S402 is directly executed. In some embodiments, it can be determined whether the terminal device can be provided with services according to the identifier of the target access network device. For example, the mobility management function network element determines whether the target access network device is managed by the mobility management function network element based on the identifier of the target access network device; if the target access network device is managed by the mobility management function network element, the mobility management function network element can serve the terminal device, otherwise, the mobility management function network element cannot serve the terminal device.
  • the mobility management function network element responds to the handover request message, and the mobility management function network element selects a target mobility management network element for the terminal device.
  • the target mobility management network element responds to the handover request message, and sends a request message to the session management function network element to update the PDU session context.
  • the session management function network element determines whether N2 switching is allowed in response to the request message for updating the PDU session context.
  • the session management function network element determines whether to allow N2 switching based on the identifier of the target access network device. If the session management function network element determines that the session service of the terminal device cannot be transmitted in the target cell of the target access network device indicated by the identifier of the target access network device, N2 switching is not allowed. For example, some services can only be accessed in a specific area, such as a campus network, and users cannot access them when they leave the campus.
  • the session management function network element sends an N4 session establishment request (N4 Session Establish Request) to the user plane function network element.
  • N4 Session Establish Request N4 Session Establish Request
  • the N4 session establishment request may be used to establish a user plane connection, and the N4 session establishment request may carry user plane tunnel information.
  • the user plane function network element sends response information of the N4 session establishment request to the session management function network element.
  • the session management function network element In response to the response information of the N4 session establishment request, the session management function network element sends the response information of the PDU session context request message to the mobility management function network element.
  • the mobility management function network element In response to the response information of the request message of the PDU session context, the mobility management function network element sends a switching request information to the target access network device.
  • the handover request message can be used to request the terminal device to be handed over to the target access network device.
  • the mobility management function network element sends the handover request message to the target access network device via the N2 interface.
  • the contents included in the handover request message can refer to the description of S303 above, which will not be repeated here.
  • the target access network device sends tunnel information of the target access network device to the mobility management function network element in response to the switching request information.
  • S408 is implemented as follows: the target access network device sends a handover request response message to the mobility management function network element in response to the handover request message.
  • the handover request response message includes path pre-handover request information, and the path pre-handover request information includes tunnel information of the target access network device.
  • the target access network device sends path pre-switching request information to the mobility management function network element in response to the switching request information, where the path pre-switching request information includes tunnel information of the target access network device.
  • the tunnel information of the target access network device includes one or more of the following information: the identity of the target access network device, application timestamp, tunnel type, tunnel bandwidth, tunnel address, and tunnel priority; the identity of the target access network device is used to identify the target access network device.
  • the mobility management function network element obtains tunnel information of the target access network device from the target access network device.
  • the mobility management function network element obtains tunnel information of the target access network device based on the path pre-switching request information.
  • the mobility management function network element In response to acquiring tunnel information of the target access network device from the target access network device, the mobility management function network element sends the tunnel information of the target access network device to the session management function network element.
  • S410 is implemented as: the mobility management function network element sends a request message for updating the PDU session context to the session management function network element, and the request message for updating the PDU session context includes the tunnel information of the target access network device.
  • the PDU session context includes: the IP (Internet Protocol) address used by the PDU session, the access point name (APN), the session management function network element address, and the user plane function network element address information.
  • IP Internet Protocol
  • API access point name
  • API session management function network element address
  • the session management function network element obtains tunnel information of the target access network device from the mobility management function network element.
  • the above S411 is implemented as follows: the session management function network element obtains the request information for updating the PDU session context sent by the mobility management, and obtains the tunnel information of the target access network device based on the request information for updating the PDU session context.
  • the session management function network element sends the tunnel information of the target access network device to the user plane function network element.
  • the above S412 is implemented as: the session management function network element sends an N4 session modification request (N4 Session Modify Request) to the user plane function network element.
  • N4 Session Modify Request N4 Session Modify Request
  • the N4 session modification request includes the tunnel information of the target access network device.
  • the N4 session modification request is used to establish a session management function network.
  • the session management function network element further sends a redundant transmission rule to the user plane function network element, the redundant transmission rule is used to configure the user plane function network element to send the first message to the target access network device and the source access network device.
  • the first message has been described in detail above and will not be repeated here.
  • the user plane function network element obtains tunnel information of the target access network device from the session management function network element.
  • the user plane functional network element installs a downlink redundant forwarder so that after the first transmission tunnel is established, the user plane functional network element can simultaneously send the same first message to the source access network device and the target access network device.
  • the first message further includes a redundant transmission identifier.
  • the user plane function network element sends the response information of S412 to the session management function network element.
  • S414 is implemented, for example, as follows: the user plane function network element sends N4 session modification request response information to the session management function network element.
  • the session management function network element sends the response information of S410 to the mobility management function network element.
  • S415 is implemented as follows: after receiving the above-mentioned S412 response information sent by the user plane function network element, the session management function network element sends the above-mentioned response information of the request to update the PDU session context to the mobility management function network element.
  • the user plane function network element sends the first message to the target access network device through the first transmission tunnel.
  • the target access network device may also cache the first message.
  • the user plane functional network element there is a second transmission tunnel between the user plane functional network element and the source access network device. After the first transmission tunnel is established, the user plane functional network element also sends the same first message to the source access network device based on the second transmission tunnel.
  • the switching request command may be used to instruct switching of the terminal device from the source access network device to the target access network device.
  • the source access network device In response to the switching command, notifies the terminal device to prepare to switch the access network device.
  • the terminal device After the source access network device notifies the terminal device that it is ready to switch the access network device, the terminal device sends a first switching completion confirmation message to the target access network device.
  • the first switching completion confirmation information is used to indicate that the path switching on the terminal device side is completed.
  • the first switching completion confirmation information is also used to request to end redundant transmission.
  • the first switching completion confirmation information is also used to request the release of resources of the source access network device used to transmit downlink messages of the terminal device.
  • the target access network device sends the first switching completion confirmation information to the mobility management function network element to inform the mobility management function network element that the switching is completed.
  • the mobility management function network element After receiving the first switching completion confirmation information, the mobility management function network element sends the first switching completion confirmation information to the session management function network element.
  • the above S420 is implemented as follows: after receiving the first switching completion confirmation information, the mobility management function network element sends a request message for updating the PDU session context to the session management function network element, and the request message for updating the PDU session context includes the first switching completion confirmation information.
  • the session management function network element After receiving the first handover completion confirmation information, the session management function network element sends the first handover completion confirmation information to the user plane function network element. information.
  • the above S421 is implemented as follows: after receiving the first switching completion confirmation information, the session management function network element sends an N4 session modification request to the user plane function network element, and the N4 session modification request includes the first switching completion confirmation information.
  • the user plane function network element After receiving the first switching completion confirmation information, the user plane function network element sends a second switching completion confirmation information to the session management function network element.
  • the above S422 is implemented as follows: after receiving the first switching completion confirmation message, the user plane function network element sends an N4 session modification request response message to the session management function network element, and the N4 session modification request response message includes a second switching completion confirmation message.
  • the second handover completion confirmation message is used to indicate the release of resources of the source access network device for transmitting downlink messages of the terminal device.
  • the second handover completion confirmation message can be used to indicate the release of the second transmission tunnel between the source access network device and the user plane functional network element, or the release of the first message including the redundant transmission identifier that has not been sent in the source access network device, etc.
  • the redundant transmission is ended, and a fourth message without a redundant transmission identifier is sent to the target access network device through the first transmission tunnel.
  • the session management function network element After receiving the second switching completion confirmation information, the session management function network element sends the second switching completion confirmation information to the mobility management function network element.
  • the above S423 is implemented as follows: after the session management function network element receives the second switching completion confirmation message, it sends a response message of the request to update the PDU session context to the mobility management function network element, and the response message of the request to update the PDU session context includes the second switching completion confirmation message.
  • the mobility management function network element releases the resources of the source access network device.
  • each network element such as a switching device
  • each network element includes a hardware structure and/or software module corresponding to the execution of each function.
  • the present disclosure can be implemented in the form of hardware or a combination of hardware and computer software. Whether a function is executed in the form of hardware or computer software driving hardware depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application.
  • the embodiment of the present disclosure can divide the switching device into functional units according to the above method example.
  • each functional unit can be divided according to each function, or two or more functions can be integrated into one processing unit.
  • the above integrated unit can be implemented in the form of hardware or in the form of software functional units. It should be noted that the division of units in the embodiment of the present disclosure is schematic and is only a logical functional division. There may be other division methods in actual implementation.
  • FIG9 is a schematic diagram of the structure of a target access network device according to some embodiments.
  • the structure may also be applicable to a chip in the target access network device, and is used to execute the actions of the target access network device or T-RAN device in the above-mentioned method embodiments.
  • the target access network device 300 includes a first transmission tunnel establishing module 301 and a first message processing module 302 .
  • the first transmission tunnel establishing module 301 is used to establish a first transmission tunnel with a user plane function network element during a handover preparation process in which a terminal device switches from a source access network device to a target access network device.
  • the first message processing module 302 is used to receive and cache a first message through a first transmission tunnel, where the first message is to be sent to a terminal device. Message.
  • the first message carries a redundant transmission identifier.
  • the first transmission tunnel establishing module 301 is used to send tunnel information of the target access network device to the mobility management function network element, and the tunnel information of the target access network device is used to establish the first transmission tunnel.
  • the above-mentioned first transmission tunnel establishment module 301 is also used to receive switching request information from a source access network device; the above-mentioned first transmission tunnel establishment module 301 is used to send path pre-switching request information to the mobility management function network element in response to the switching request information, and the path pre-switching request information includes tunnel information of the target access network device.
  • the first transmission tunnel establishing module 301 is further configured to receive path pre-switching request response information from a mobility management function network element.
  • the above-mentioned first transmission tunnel establishment module 301 is also used to receive switching request information from the mobility management function network element; the above-mentioned first transmission tunnel establishment module 301 is used to send switching request response information to the mobility management function network element in response to the switching request information, and the switching request response information includes tunnel information of the target access network device.
  • the first message processing module 302 is further used to establish a communication connection with a terminal device. Through the communication connection with the terminal device, the first message processing module 302 sends a first message to the terminal device.
  • the first message processing module 302 is used to exclude the second message from the first message to obtain a third message; the second message is a message that the source access network device has successfully sent to the terminal device in the first message received by the source access network device through the second transmission tunnel.
  • the first message processing module 302 sends the third message to the terminal device through the communication connection with the terminal device.
  • the first message processing module 302 is used for the target access network device to receive the sequence number of the second message from the source access network device; the target access network device excludes the second message from the first message based on the sequence number of the second message to obtain a third message.
  • the first message processing module 302 is further used to receive a fourth message that does not carry a redundant transmission identifier through the first transmission tunnel after the switching is completed; the target access network device sends the fourth message to the terminal device.
  • FIG10 is a schematic diagram of the structure of a mobility management function network element according to some embodiments, which is used to execute the actions of the mobility management function network element in the above-mentioned method embodiments.
  • the mobility management function network element 500 includes a first acquisition module 501 and a first sending module 502 .
  • the first acquisition module 501 is used to obtain tunnel information of the target access network device from the target access network device during the switching preparation process of the terminal device switching from the source access network device to the target access network device.
  • the tunnel information of the target access network device is used to establish a first transmission tunnel between the target access network device and the user plane functional network element.
  • the first sending module 502 is used to send the tunnel information of the target access network device to the session management function network element.
  • the first acquisition module 501 is used to receive path pre-switching request information from a target access network device, where the path pre-switching request information includes tunnel information of the target access network device.
  • the first sending module 502 is further configured to send path pre-switching request response information to the target access network device.
  • the first sending module 502 is further used to send switching request information to the target access network device; the first obtaining module 501 is used to receive switching request response information from the target access network device, and the switching request response information includes tunnel information of the target access network device.
  • FIG11 is a schematic diagram of the structure of a session management function network element according to some embodiments, which is used to execute the actions of the session management function network element in the above-mentioned method embodiments.
  • the session management function network element 600 includes a second acquisition module 601 and a second sending module 602 .
  • the second acquisition module 601 is used to obtain the tunnel information of the target access network device from the mobility management function network element during the handover preparation process of the terminal device switching from the source access network device to the target access network device.
  • the tunnel information of the target access network device is used to establish the target access network device and the The first transmission tunnel between user plane functional network elements.
  • the second sending module 602 is used to send the tunnel information of the target access network device to the user plane function network element.
  • the session management function network element 600 further includes a redundancy configuration module 603.
  • the redundancy configuration module 603 is used to configure a redundant transmission rule for the user plane function network element.
  • the redundant transmission rule is used to configure the user plane function network element to send a first message to the target access network device and the source access network device.
  • the first message is a message to be sent to the terminal device.
  • the first message carries a redundant transmission identifier.
  • the second sending module 602 is further used to send instruction information for instructing to stop redundant transmission to the user plane management function network element during the handover execution process of the terminal device switching from the source access network device to the target access network device.
  • Figure 12 is a schematic diagram of the structure of the user plane function network element according to some embodiments, which is used to perform the actions of the user plane function network element in the above-mentioned method embodiments.
  • the user plane function network element 700 includes a second tunnel establishing module 701 and a second message processing module 702 .
  • the second tunnel establishing module 701 is used to establish a first transmission tunnel with a target access network device during a handover preparation process in which a terminal device switches from a source access network device to a target access network device.
  • the second message processing module 702 is used to send a first message to a target access network device through a first transmission tunnel, where the first message is a message to be sent to a terminal device.
  • the second tunnel establishment module 701 is used to obtain tunnel information of the target access network device from the session management function network element, and the tunnel information of the target access network device is used to establish a first transmission tunnel between the target access network device and the user plane function network element.
  • the second message processing module 702 is further used to receive a redundant transmission rule sent by a session management function network element.
  • the redundant transmission rule is used to configure the user plane function network element to send a first message to the target access network device and the source access network device, where the first message is a message to be sent to the terminal device.
  • the second message processing module 702 is further configured to send the first message to the source access network device through the second transmission tunnel.
  • the first message carries a redundant transmission identifier.
  • the above-mentioned second message processing module 702 is also used to receive indication information sent by the session management function network element to instruct to stop redundant transmission during the switching execution process of the terminal device from the source access network device to the target access network device; based on the indication information, send a fourth message without a redundant transmission identifier to the target access network device through the first transmission tunnel.
  • the embodiment of the present disclosure provides another possible structure of the target access network device, mobility management function network element, session management function network element, and user plane function network element involved in the above-mentioned embodiment.
  • the communication node 400 includes: a processor 402 and a bus 404.
  • the communication node 400 may also include a memory 401.
  • the communication node 400 may also include a communication interface 403.
  • the processor 402 may be a device that implements or executes various exemplary logic blocks, modules, and circuits described in conjunction with the embodiments of the present disclosure.
  • the processor 402 may be a central processing unit, a general-purpose processor, a digital signal processor, an application-specific integrated circuit, a field programmable gate array, or other programmable logic devices, transistor logic devices, hardware components, or any combination thereof.
  • the processor 402 may be a device that implements or executes various exemplary logic blocks, modules, and circuits described in conjunction with the embodiments of the present disclosure.
  • the processor 402 may also be a combination that implements computing functions, such as a combination of one or more microprocessors, a combination of a DSP and a microprocessor, and the like.
  • the communication interface 403 is used to connect with other devices through a communication network.
  • the communication network can be Ethernet, wireless access network, wireless local area network (WLAN), etc.
  • the memory 401 may be a read-only memory (ROM) or other types of static storage devices that can store static information and instructions, a random access memory (RAM) or other types of dynamic storage devices that can store information and instructions, or an electrically erasable programmable read-only memory (Electrically Erasable Programmable Read-Only Memory (EEPROM).
  • EEPROM Electrically Erasable Programmable Read-Only Memory
  • disk storage media or other magnetic storage devices or any other medium that can be used to carry or store desired program code in the form of instructions or data structures and can be accessed by a computer, but is not limited to these.
  • the memory 401 may exist independently of the processor 402, and the memory 401 may be connected to the processor 402 via a bus 404 to store instructions or program codes.
  • the processor 402 calls and executes the instructions or program codes stored in the memory 401, the switching method provided in the embodiment of the present disclosure can be implemented.
  • the memory 401 may also be integrated with the processor 402 .
  • the bus 404 may be an Extended Industry Standard Architecture (EISA) bus, etc.
  • the bus 404 may be divided into an address bus, a data bus, a control bus, etc.
  • FIG13 only uses one thick line, but does not mean that there is only one bus or one type of bus.
  • Some embodiments of the present disclosure provide a computer-readable storage medium (e.g., a non-transitory computer-readable storage medium), in which a computer program instruction is stored, and when the computer program instruction is executed on a computer, the computer executes the switching method described in any of the above embodiments.
  • the computer may be the above communication node or a processor in the communication node.
  • the above-mentioned computer-readable storage media may include, but are not limited to: magnetic storage devices (e.g., hard disks, floppy disks or magnetic tapes, etc.), optical disks (e.g., compact disks (CD), digital versatile disks (DVD), etc.), smart cards and flash memory devices (e.g., erasable programmable read-only memories (EPROM), cards, sticks or key drives, etc.).
  • the various computer-readable storage media described in the embodiments of the present disclosure may represent one or more devices and/or other machine-readable storage media for storing information.
  • the term "machine-readable storage medium" may include, but is not limited to, wireless channels and various other media capable of storing, containing and/or carrying instructions and/or data.
  • An embodiment of the present disclosure provides a computer program product including instructions.
  • the computer program product When the computer program product is run on a computer, the computer is enabled to execute the switching method described in any one of the above embodiments.

Abstract

提供一种切换方法及通信节点、存储介质。该方法包括：在终端设备从源接入网设备切换到目标接入网设备的切换准备过程中，目标接入网设备与用户面网元建立第一传输隧道；目标接入网设备通过第一传输隧道接收并缓存第一报文，第一报文为待发送给终端设备的报文。

Description

切换方法及通信节点、存储介质
本公开要求于2022年09月30日提交的、申请号为202211218030.0的中国专利申请的优先权，其全部内容通过引用结合在本申请中。
技术领域
本公开涉及通信技术领域，尤其涉及一种切换方法及通信节点、存储介质。
背景技术
为了保证业务的连续性，若终端设备从源接入网设备的覆盖范围移动至目标接入网设备的覆盖范围，需要将终端设备从源接入网设备切换至目标接入网设备，进而使得目标接入网设备为终端设备提供服务。
发明内容
一方面，本公开实施例提供一种切换方法。该切换方法包括：在终端设备从源接入网设备切换到目标接入网设备的切换准备过程中，目标接入网设备与用户面网元建立第一传输隧道；目标接入网设备通过第一传输隧道接收并缓存第一报文，第一报文为待发送给终端设备的报文。
再一方面，本公开实施例提供一种目标接入网设备。该目标接入网设备包括：第一传输隧道建立模块，用于在终端设备从源接入网设备切换到目标接入网设备的切换准备过程中，与用户面网元建立第一传输隧道；第一报文处理模块，用于通过第一传输隧道接收并缓存第一报文，第一报文为待发送给终端设备的报文。
又一方面，本公开实施例提供一种切换方法。该切换方法包括：在终端设备从源接入网设备切换到目标接入网设备的切换准备过程中，移动管理网元从目标接入网设备获取目标接入网设备的隧道信息，目标接入网设备的隧道信息用于建立目标接入网设备与用户面网元之间的第一传输隧道；移动管理网元向会话管理网元发送目标接入网设备的隧道信息。
又一方面，本公开实施例提供一种移动管理网元。该移动管理网元包括：第一获取模块，用于在终端设备从源接入网设备切换到目标接入网设备的切换准备过程中，从目标接入网设备获取目标接入网设备的隧道信息，目标接入网设备的隧道信息用于建立目标接入网设备与用户面功能网元之间的第一传输隧道；第一发送模块，用于向会话管理网元发送目标接入网设备的隧道信息。
又一方面，本公开实施例提供一种切换方法。该切换方法包括：在终端设备从源接入网设备切换到目标接入网设备的切换准备过程中，会话管理网元从移动管理网元获取目标接入网设备的隧道信息，目标接入网设备的隧道信息用于建立目标接入网设备与用户面网元之间的第一传输隧道；会话管理网元向用户面网元发送目标接入网设备的隧道信息。
又一方面，本公开实施例提供一种会话管理网元。该会话管理网元包括：第二获取模块，用于在终端设备从源接入网设备切换到目标接入网设备的切换准备过程中，从移动管理网元获取目标接入网设备的隧道信息，目标接入网设备的隧道信息用于建立目标接入网设备与用户面功能网元之间的第一传输隧道；第二发送模块，用于向用户面网元发送目标接入网设备的隧道信息。
又一方面，本公开实施例提供一种切换方法。该切换方法包括：在终端设备从源接入网设备切换到目标接入网设备的切换准备过程中，用户面网元与目标接入网设备建立第一传输隧道；用户面网元通过第一传输隧道向目标接入网设备发送第一报文，第一报文为待发送给终端设备的报文。
又一方面，本公开实施例提供一种用户面网元。该用户面网元包括：第二隧道建立模块，用于在终端设备从源接入网设备切换到目标接入网设备的切换准备过程中，与目标接入网设备建立第一传输隧道；第二 报文处理模块，用于通过第一传输隧道向目标接入网设备发送第一报文，第一报文为待发送给终端设备的报文。
又一方面，本公开实施例提供一种通信节点。该通信节点包括：存储器和处理器；存储器和处理器耦合；存储器用于存储计算机程序；处理器执行计算机程序时实现上述任一实施例所述的切换方法。
又一方面，本公开实施例提供一种计算机可读存储介质。该计算机可读存储介质上存储有计算机程序指令，该计算机程序指令被处理器执行时实现上述任一实施例所述的切换方法。
又一方面，本公开实施例提供一种计算机程序产品。该计算机程序产品包括计算机程序指令，该计算机程序指令被处理器执行时实现上述任一实施例所述的切换方法。
附图说明
图1为根据一些实施例的一种通信系统的示意图；
图2为根据一些实施例的另一种通信系统的示意图；
图3为根据一些实施例的又一种通信系统的示意图；
图4为根据一些实施例的一种切换方法；
图5为根据一些实施例的另一种切换方法；
图6为根据一些实施例的又一种切换方法；
图7为根据一些实施例的又一种切换方法；
图8为根据一些实施例的又一种切换方法；
图9为根据一些实施例的一种目标接入网设备的结构示意图；
图10为根据一些实施例的一种移动管理网元的结构示意图；
图11为根据一些实施例的一种会话管理网元的结构示意图；
图12为根据一些实施例的一种用户面网元的结构示意图；
图13为根据一些实施例的一种通信节点的结构示意图。
具体实施方式
下面将结合本申请实施例中的附图，对本申请实施例中的技术方案进行清楚、完整的描述。
在本申请的描述中，除非另有说明，“/”表示“或”的意思，例如，A/B可以表示A或B。本文中的“和/或”仅仅是一种描述关联对象的关联关系，表示可以存在三种关系，例如，A和/或B，可以表示：仅A，仅B，以及A和B。
此外，“至少一个”是指一个或多个，“多个”是指两个或两个以上。为了便于清楚描述本申请实施例的技术方案，在本申请的实施例中，采用了“第一”、“第二”等字样对功能和作用基本相同的相同项或相似项进行区分。应理解，“第一”、“第二”等字样并不对数量和执行次序进行限定，并且“第一”、“第二”等字样也并不限定一定不同。
另外，本公开中，“示例性地”或者“例如”等词用于表示例子、例证或说明。本公开中被描述为“示例性地”或者“例如”的任何实施例或设计方案不应被解释为比其他实施例或设计方案更优选或更具优势。确切而言，使用“示例性地”或者“例如”等词旨在以详细方式呈现相关概念。
本公开实施例的技术方案可以应用于各种通信系统。例如：全球移动通信系统(Global System For Mobile Communication，GSM)、演进通用无线陆地接入(Evolved Universal Terrestrial Radio Access，E-UTRA)系统、通用移动通信系统(Universal Mobile Telecommunications System，UMTS)以及UMTS演进版本、长期演进(Long Term Evolution，LTE)和基于LTE演进的各种版本、第五代(5th-Generation，5G)通信系统、以及新空 口(New Radio，NR)等下一代通信系统中。此外，上述通信系统还可以适用于面向未来的通信技术，并都适用本公开实施例提供的技术方案。
可以理解的是，本公开实施例描述的系统架构以及业务场景是为了更加清楚地说明本公开实施例的技术方案，并不构成对于本公开实施例提供的技术方案的限定，本领域普通技术人员可知，随着网络架构的演变和新业务场景的出现，本公开实施例提供的技术方案对于类似的技术问题，同样适用。
在当前的第四代(4th-Generation，4G)网络中，LTE系统中的演进式基站(evolved Node Base Station，eNB，也可以称为LTE eNB)通过S1接口与4G核心网络(例如，分组核心网(Evolved Packet Core，EPC))连接，不同的LTE eNB之间通过X2接口连接。例如，图1中LTE eNB1和LTE eNB2之间通过X2接口连接。图1示出了LTE系统的网络架构，X2接口支持两个LTE eNB之间的数据和信令的直接传输。在LTE系统中，终端设备(User Equipment，UE)通过各自接入的LTE eNB与EPC进行数据传输或者信令传输。
此外，在当前的5G网络中，对于新空口(New Radio，NR)系统中的每个下一代节点B(The Next Generation Node B，gNB)，本公开实施例将其称为NR gNB，通过N2接口与NG核心(NG-Core)网连接，不同的NR gNB之间通过Xn接口连接，例如，gNB1和gNB2之间通过Xn接口连接。每个NR gNB均与NR系统中的至少一个终端设备连接。图2示出了NR系统的网络架构。在实际应用中上述多个设备之间的连接为无线连接，为了方便直观地表示各个设备之间的连接关系，图2中采用实线示意。
在本公开实施例中，会话管理网元也可以被称为会话管理功能网元，用户面网元也可以被称为用户面功能网元，本公开实施例对此不作限定。
进一步地，如图3所示，对于图2所示的通信系统，gNB所对应的网元或者实体可以为无线接入网(Radio Access Network，RAN)、NG-Core网包括的网元可以为会话管理功能(Session Management Function，SMF)网元、用户面功能(User Plane Function，UPF)网元、策略控制功能(Policy Control Function，PCF)网元、应用功能(Application Function，AF)网元、鉴权服务器功能(Authentication Server Function，AUSF)网元、统一数据管理(Unified Data Management，UDM)网元、网络开放功能(Network Exposure Function，NEF)网元、网络仓库贮存功能(Network Repository Function，NRF)网元以及数据网络(Data Network，DN)、安全锚点功能(Security Anchor Function，SEAF)网元或者网络切片选择功能(Network Slice Selection Function，NSSF)网元等。本公开实施例对此不作限定。
在本公开实施例中，移动管理网元也可以被称为移动性管理功能网元或接入和移动性管理功能网元，本公开实施例对此不作限定。UE通过N1接口(简称N1)与AMF(Access And Mobility Management Function，接入和移动性管理功能)网元通信。AMF网元通过N11接口(简称N11)与SMF网元通信。SMF网元通过N4接口(简称N4)与一个或者多个UPF网元通信。一个或多个UPF网元中任意两个UPF网元通过N9接口(简称N9)通信。UPF网元通过N6接口(简称N6)与数据网络(Data Network，DN)通信。终端设备通过接入网设备(例如，RAN设备)接入网络。接入网设备与AMF网元之间通过N2接口(简称N2)通信。SMF网元通过N7接口(简称N7)与PCF网元通信，PCF网元通过N5接口与AF网元通信。接入网设备通过N3接口(简称N3)与UPF网元通信。任意两个或两个以上的AMF网元之间通过N14接口(简称N14)通信。SMF网元通过N10接口(简称N10)与UDM网元通信。AMF网元通过N12接口(简称N12)与AUSF网元通信。AUSF网元通过N13接口(简称N13)与UDM网元通信。AMF网元通过N8接口(简称N8)与UDM网元通信。
需要说明的是，图3中的各个网元之间的接口名字只是一个示例，实现中接口名字可能为其他名字，本公开实施例对此不作限定。
此外，对图3所示的通信系统中各个网元或设备的功能作如下说明。
AMF网元：属于核心网网元，主要负责信令处理部分，例如：接入控制、移动性管理、附着与去附着以及网关选择等功能。AMF网元在为终端设备中的会话提供服务的情况下，会为该会话提供控制面的存储资源以存储会话标识、与会话标识关联的SMF网元标识等。
(无线)接入网((Radio)Access Network，(R)AN)设备：包括RAN设备和AN设备。RAN设备主要是第三代合作伙伴计划(3rd Generation Partnership Project，3GPP)网络无线网络设备，AN可以是非(non)-3GPP定义的接入网设备。RAN设备：主要负责空口侧的无线资源管理、服务质量(Quality Of Service，QoS)管理、数据压缩和加密等功能。所述接入网设备可以包括各种形式的基站，例如：宏基站，微基站(也称为小站)，中继站，接入点等。在采用不同的无线接入技术的系统中，具备基站功能的设备的名称可能会有所不同。例如，在第五代系统中，具有基站功能的设备称为RAN。在LTE系统中，具有基站功能的设备称为演进的节点B(evolved NodeB，eNB或者eNodeB)。在第三代(3rd Generation，3G)系统中，具有基站功能的设备称为节点B(Node B)等。AN设备：允许终端设备和3GPP核心网之间采用非3GPP技术互连互通。非3GPP技术例如：无线保真(Wireless Fidelity，Wi-Fi)、全球微波互联接入(World Wide Interoperability for Microwave Access，WiMAX)、码分多址(Code Division Multiple Access，CDMA)网络等。
SMF网元：负责用户面功能网元选择，用户面功能网元重定向，因特网协议(Internet Protocol，IP)地址分配，承载的建立、修改和释放以及服务质量(Quality of Service，QoS)控制。
UPF网元：负责终端设备中用户数据的转发和接收。可以从数据网络接收用户数据，通过接入网设备传输给终端设备。UPF网元还可以通过接入网设备从终端设备接收用户数据，并将用户数据转发到数据网络。UPF网元中为终端设备提供服务的传输资源和调度功能由SMF网元管理控制。
PCF网元：主要支持提供统一的策略框架来控制网络行为，给控制层网络功能提供策略规则，同时负责获取与策略决策相关的用户签约信息。
AUSF网元：主要提供认证和鉴权功能。
NEF网元：主要支持3GPP网络和第三方应用安全的交互，NEF网元能够安全地向第三方开放网络能力和事件，用于加强或者改善应用服务质量，3GPP网络同样可以安全地从第三方获取相关数据，用以增强网络的智能决策；同时该NEF网元支持从统一数据库恢复结构化数据或者向统一数据库中存储结构化数据。
AF网元：主要支持与3GPP核心网交互来提供服务。例如影响数据路由决策，策略控制功能或者向网络侧提供第三方的一些服务。
本公开实施例中的终端设备可以是向用户提供语音和/或数据连通性的设备、具有无线连接功能的手持式设备、或连接到无线调制解调器的其他处理设备。无线终端设备可以经由RAN与一个或多个核心网进行通信。无线终端设备可以是手持终端设备、笔记本电脑、用户单元(Subscriber Unit)、蜂窝电话(Cellular Phone)、智能电话(Smart Phone)、无线数据卡、个人数字助理(Personal Digital Assistant，PDA)电脑、平板型电脑、无线调制解调器(Modem)、手持设备(Hand Held)、膝上型电脑(Laptop Computer)、无绳电话(Cordless Phone)或者无线本地环路(Wireless Local Loop，WLL)台、机器类型通信(Machine Type Communication，MTC)终端设备或是其他可以接入网络的设备。终端设备与接入网设备之间采用某种空口技术(例如，3GPP接入技术或者非3GPP接入技术)相互通信。
在上述图1至图3所示的通信系统中，无论是LTE eNB、或eLTE eNB，还是gNB，一个基站一般可以覆盖一个或多个小区。每个小区有一定的覆盖范围，该覆盖范围相对固定。如果终端设备在移动过程中，离开服务小区进入另一个小区，且该另一个小区和前述服务小区由不同的基站管理(例如，前述服务小区属于 源基站，该另一个小区属于目标基站)，则该终端设备需要在目前的移动管理技术的控制下从源基站切换到目标基站。
在一些技术中，第五代移动通信技术切换流程定义了包括基于Xn接口的切换流程和基于N2接口的切换流程。
Xn接口为两个接入网设备之间的接口，基于Xn接口的切换流程可以理解为在源无线接入网(Source Radio Access Network，S-RAN)设备确定为终端设备切换接入网设备的情况下，由S-RAN设备向目标无线接入网(Target Radio Access Network，T-RAN)设备发送切换请求；在S-RAN设备确定T-RAN设备同意将终端设备切换至T-RAN设备的情况下，S-RAN设备向终端设备发起切换流程，例如，S-RAN设备向终端设备发送切换命令，以将终端设备切换至T-RAN设备。
N2为接入网设备和AMF网元之间的接口，基于N2的切换流程可以理解为：在S-RAN设备确定为终端设备切换接入网设备的情况下，S-RAN设备向S-AMF网元发送切换请求，S-AMF网元为与S-RAN设备连接的AMF网元；由S-AMF网元选择T-AMF网元之后，再由S-AMF网元向T-AMF网元发送切换请求，T-AMF网元将切换请求发送给T-RAN设备，T-AMF网元为与T-RAN设备连接的AMF网元；当T-AMF网元从T-RAN设备收到切换请求确认之后，将切换请求确认通过S-SMF网元发送给S-RAN设备，在S-RAN设备同意将终端设备切换至T-RAN设备的情况下，S-RAN设备向终端设备发起切换流程，如向终端设备发送切换命令，以将终端设备切换至T-RAN设备。需要说明的是，T-AMF网元和S-AMF网元可以是同一个AMF网元。
无论是基于N2接口的切换流程还是基于Xn接口的切换流程，S-RAN设备在确定执行切换流程(即向终端设备发送切换命令)之前，T-RAN设备均不能直接从用户面功能网元获取发往终端设备的下行报文。因此，在切换过程中，T-RAN设备需要获取来自S-RAN设备的发往终端设备的下行报文，或者等待与用户面建立传输隧道后获取发往终端设备的下行报文。这样，可能会导致在终端设备切换至T-RAN设备时，T-RAN设备由于未接收到发往终端设备的下行报文而导致其无法立刻向终端设备发送该下行报文，进而导致切换的时延较大，降低了通信的可靠性。
基于此，本公开实施例提供一种切换方法，该方法通过在切换接入网设备的过程中，预先建立目标接入网设备与用户面功能网元之间的第一传输隧道，以使得在切换完成前，目标接入网设备可以直接从用户面功能网元获取发往终端设备的下行报文。这样，在切换过程中，目标接入网设备可以根据已建立的第一传输隧道直接获取发往终端设备的下行报文，而不需要等待来自源接入网设备的发往终端设备的下行报文，或者等待与用户面建立传输隧道后获取发往终端设备的下行报文，进而降低了切换接入网设备时报文的传输时延，提高了通信的可靠性。
需要指出的是，本公开各实施例之间可以相互借鉴或参考，例如，相同或相似的步骤、方法实施例和装置实施例之间，均可以相互参考，对此不予限制。
图4为根据一些实施例的一种切换方法。参照图4，本公开实施例提供的切换方法包括以下步骤。
S101、在终端设备从源接入网设备切换到目标接入网设备的切换准备过程中，目标接入网设备与用户面功能网元建立第一传输隧道。
源接入网设备为切换前终端设备接入的接入网设备，目标接入网设备为切换结束时终端设备接入的接入网设备。切换准备过程为预先建立第一传输隧道的过程。
第一传输隧道可以为用户面功能网元与目标接入网设备之间N3隧道，用于在执行终端设备的接入网设备间切换流程时，传输用户面功能网元与目标接入网设备之间的待发往终端设备的下行报文。例如，第一传 输隧道的建立方式可以参照下述图6对应的实施例中所述。
在一些实施例中，在切换完成前，用户面功能网元与源接入网设备之间还存在第二传输隧道。第二传输隧道可以为用户面功能网元与源接入网设备之间的N3隧道，用于在执行终端设备的接入网设备间切换流程时，传输用户面功能网元与源接入网设备之间发往终端设备的下行报文。
S102、用户面功能网元通过第一传输隧道向目标接入网设备发送第一报文。第一报文为待发送给终端设备的报文。
在一些实施例中，在核心网侧未发生用户面功能网元切换的情况下，S102中的用户面功能网元通过第二传输隧道向源接入网设备发送第一报文。
在一些实施例中，在核心网侧发生用户面功能网元切换的情况下，S102中提及的用户面功能网元为目标用户面功能网元。在一些实施例中，在源用户面功能网元作为会话锚点的用户面功能网元时，目标用户面功能网元可以从源用户面功能网元获取到第一报文。此外，源用户面功能网元还通过第二传输隧道向源接入网设备发送第一报文。
相应地，源接入网设备接收该第一报文。可以理解的是，源接入网设备接收到的第一报文与目标接入网设备接收到的第一报文是同一个报文。可以理解的是，第二传输隧道是源接入网设备与用户面功能网元预先建立的。
在一些实施例中，第一报文携带冗余传输标识，以表示该第一报文是用户面功能网元以冗余传输的方式分别传输给源接入网设备和目标接入网设备。
S103、目标接入网设备通过第一传输隧道接收并缓存第一报文。
在一些实施例中，上述第一报文携带有冗余传输标识。冗余传输标识用于该标记报文是由用户面功能网元同时向源接入网设备和目标接入网设备冗余传输所得的报文；可以理解的是，对于标记了冗余传输标识的第一报文，在目标接入网设备和源接入网设备存在相同的该第一报文。可以理解的是，对本公开实施例冗余传输标识的位数，以及在第一报文中的位置不作限制。在一些实施例中，上述冗余传输标识可以由用户面功能网元标记。
在一些实施例中，上述第一报文可以包括用户面功能网元待发送给终端设备的一个或多个下行报文。示例性地，当待发送给终端设备的第一报文的数量为一个时，该第一报文即为待发送给终端设备的下行报文。当待发送给终端设备的第一报文的数量为多个时，该第一报文可以包括将该多个待发送给终端设备的下行报文分批处理后得到一个批次或多个批次的报文。
此外，可以理解的是，目标接入网设备在哪个接口(例如上述Xn接口或上述N2接口)上接收第一报文，可以由目标接入网设备所处的网络决定。例如，若目标接入网设备和源接入网设备之间存在Xn接口，则目标接入网设备通过Xn接口接收第一报文；若目标接入网设备和移动性管理功能网元之间存在N2接口，则目标接入网设备通过N2接口接收第一报文。
可以看出，图4所示的实施例在终端设备从源接入网设备切换到目标接入网设备的切换准备过程中预先建立目标接入网设备与用户面功能网元之间的第一传输隧道，以使得在切换完成前，目标接入网设备可以直接从用户面功能网元获取发往终端设备的下行报文。这样，在切换过程中，目标接入网设备可以始终根据已建立的第一传输隧道获取发往终端设备的下行报文，而不需要等待来自源接入网设备的发往终端设备的下行报文，或者等待与用户面建立传输隧道后获取发往终端设备的下行报文，进而降低了切换接入网设备时报文的传输时延，提高了通信的可靠性。
在一些实施例中，如图5所示，在S103之后，上述方法还包括S104至S105。
S104、目标接入网设备与终端设备建立通信连接。
S105、目标接入网设备通过与终端设备之间的通信连接，向终端设备发送第一报文。
在一些实施例中，目标接入网设备向终端设备发送其缓存的第一报文，即将自身缓存的待发送给终端设备的报文全部发送给终端设备。
在一些实施例中，上述目标接入网设备通过与终端设备之间的通信连接，向终端设备发送第一报文，例如实现为：目标接入网设备从第一报文中排除第二报文，得到第三报文。第二报文为源接入网设备通过第二传输隧道接收到的第一报文中，源接入网设备已成功发送给终端设备的报文；目标接入网设备通过与终端设备之间的通信连接，向终端设备发送第三报文，即向终端设备发送第一报文中的部分报文(如未发给终端设备的报文)。进一步地，上述目标接入网设备从第一报文中排除第二报文，得到第三报文，例如可以实现为：目标接入网设备接收来自于源接入网设备的第二报文的序列号；目标接入网设备基于第二报文的序列号，从第一报文中排除所述第二报文，得到第三报文。
基于此，使得目标接入网设备可以从缓存的第一报文中排除终端设备已经收到的报文，避免重复发送，提高通信的效率和可靠性。
在一些实施例中，在S104或S105之后，目标接入网设备与终端设备已经建立了通信连接，用户面功能网元可以不再向源接入网设备传输发往终端设备的报文，因此可以终止冗余传输，以节省报文传输的开销，提高通信效率。
示例性地，在终端设备在所述终端设备从源接入网设备切换到目标接入网设备的切换执行过程中，用户面功能网元还可以接收会话管理功能网元发送的用于指示停止冗余传输的指示信息，并基于该指示信息，通过第一传输隧道向目标接入网设备发送未携带冗余传输标识的第四报文。相应地，目标接入网设备还可以通过第一传输隧道接收未携带冗余传输标识的第四报文。可以理解的是，该第四报文为发往终端设备的不包括冗余传输标识的下行报文。进一步地，目标接入网设备还可以向终端设备发送该第四报文。
为便于理解，下面对本公开实施例提供的一种第一传输隧道的建立方式作详细说明。
参照图6，上述第一传输隧道按照以下方式建立。
S201、目标接入网设备向移动性管理功能网元发送目标接入网设备的隧道信息。
目标接入网设备的隧道信息用于建立目标接入网设备与用户面功能网元之间的第一传输隧道。
在一些实施例中，目标接入网设备的隧道信息包括以下信息的一种或多种：目标接入网设备的身份标识、申请时间戳、隧道类型、隧道带宽、隧道地址、以及隧道优先级；目标接入网设备的身份标识用于识别目标接入网设备。
在一些实施例中，若目标接入网设备接收到移动性管理功能网元或源接入网设备发送的切换请求信息，则执行上述S201。切换请求信息用于请求将终端设备切换至目标接入网设备。
例如，在基于Xn接口的切换中，目标接入网设备接收到源接入网设备发送的切换请求信息，向移动性管理功能网元发送目标接入网设备的隧道信息。
又例如，在基于N2接口的切换中，目标接入网设备接收到移动性管理功能网元发送的切换请求信息，向移动性管理功能网元发送目标接入网设备的隧道信息。
在一些实施例中，上述S201例如可以实现为：目标接入网设备向移动性管理功能网元发送路径预切换请求信息。路径预切换请求信息包括目标接入网设备的隧道信息。
S202、移动性管理功能网元从目标接入网设备获取目标接入网设备的隧道信息。
在一些实施例中，上述S202例如可以实现为：移动性管理功能网元获取目标接入网设备发送的路径预 切换请求信息，基于路径预切换请求信息，获取目标接入网设备的隧道信息。
S203、移动性管理功能网元向会话管理功能网元发送目标接入网设备的隧道信息。
在一些实施例中，S203例如实现为：移动性管理功能网元向会话管理功能网元发送更新PDU会话上下文的请求(Nsmf_PDUSession_UpdateSMContext Request)消息，该Nsmf_PDUSession_UpdateSMContext Request信息中包括目标接入网设备的隧道信息。
在一些实施例中，PDU会话上下文包括：PDU会话使用的IP(Internet Protocol)地址、接入点名字(Access Point Name，APN)、会话管理功能网元地址、以及用户面功能网元地址信息。
S204、会话管理功能网元从移动性管理功能网元获取目标接入网设备的隧道信息。
在一些实施例中，上述S204，例如实现为：会话管理功能网元获取移动性管理功能网元发送的Nsmf_PDUSession_UpdateSMContext Request信息，并基于该Nsmf_PDUSession_UpdateSMContext Request信息，获取目标接入网设备的隧道信息。
S205、会话管理功能网元向用户面功能网元发送目标接入网设备的隧道信息。
在一些实施例中，上述S205例如实现为：会话管理功能网元向用户面功能网元发送N4会话修改请求(N4session modify request)。
上述N4会话修改请求包括目标接入网设备的隧道信息。
S206、用户面功能网元从会话管理功能网元获取到目标接入网设备的隧道信息。
在一些实施例中，上述S206例如实现为：用户面功能网元获取会话管理功能网元发送的N4会话修改请求，并基于该N4会话修改请求，获取目标接入网设备的隧道信息。
在一些实施例中，用户面功能网元基于该目标接入网设备的隧道信息，为目标接入网设备分配传输隧道。
S207、用户面功能网元向会话管理功能网元发送上述S205的响应信息。
在一些实施例中，上述S207例如实现为：用户面功能网元向会话管理功能网元发送N4会话修改请求响应信息。
S208、在接收到用户面功能网元发送的上述S205响应信息后，会话管理功能网元向移动性管理功能网元发送上述S203的响应信息。
在一些实施例中，S208例如实现为：在接收到用户面功能网元发送的上述S205响应信息后，会话管理功能网元向移动性管理功能网元发送上述更新PDU会话上下文的请求的响应信息。
在一些实施例中，在基于N2接口的切换中，在上述S208之后，第一传输隧道建立完成。
在另一些实施例中，在基于Xn接口的切换中，在上述S208之后，还包括S209。
S209、在接收到会话管理功能网元发送的上述S203响应信息后，移动性管理功能网元向目标接入网设备发送上述S201的响应信息。
在一些实施例中，上述S209例如实现为：在接收到会话管理功能网元发送的上述S203响应信息后，移动性管理功能网元向目标接入网设备发送路径预切换请求信息的响应信息。
在基于Xn接口的切换中，在上述S209之后，第一传输隧道建立完成。
需要说明的是，上述S207至S209依次为S205、S203、以及S201的响应信息，可以参考一些技术中的内容，图6中未示出上述S207至S209。
为更清楚地说明本公开实施例所提供的切换方法，下面以基于Xn接口的切换为例进行描述。参照图7，例如如下所述。
S301、终端设备接收源接入网设备的测量控制(Measurement Control)命令，并向源接入网设备发送测量报告(Measurement Reports)。
源接入网设备可以是5G的gNB、NR或其他RAN设备，本公开实施例对此不作限定。
在一些实施例中，终端设备可以通过源接入网设备接入第一网络，源接入网设备为终端设备的服务小区所属的RAN设备；终端设备可以周期性地测量终端设备的服务小区的信号质量和终端设备的邻小区的信号质量。在一些实施例中，上述第一网络可以为4G核心(Evolved Packet Core，EPC)网或者5G核心(Next Generation Core，NG-Core)网。
在一些实施例中，在终端设备向源接入网设备发送测量报告前，终端设备接收源接入网设备发送的用于测量建立的测量控制(Measurement Control)命令，并根据收到的测量控制命令建立相应的测量。进一步地，终端设备基于建立的测量，向源接入网设备发送测量报告。若终端设备因自身设备故障或通信故障等原因没能成功建立测量，则向源接入网设备发送测量失败信息(例如，Measurement Control Failure Information)。或者，若终端设备成功建立了测量并得到了测量结果，向源接入网设备发送包括该测量结果的测量报告。
上述测量报告用于指示终端设备的信号质量。例如，上述测量报告中的测量结果可以包括：终端设备的服务小区所属的RAN设备的信号质量和终端设备的邻小区所属的RAN设备的信号质量。上述信号质量可以包括参考信号接收功率(Reference Signal Receiving Power，RSRP)。或者，信号质量可以包括参考信号接收质量(Reference Signal Receiving Quality，RSRQ)。或者，信号质量可以包括RSRP和RSRQ。可以理解的是，上述信号质量仅为示例，本公开对此不作限制。
在一些实施例中，上述向源接入网设备发送测量报告例如可以实现为：终端设备周期性地向源接入网设备发送测量报告；或者，终端设备由事件触发向源接入网设备发送测量报告，向源接入网设备发送测量报告。
在一些实施例中，上述事件触发包括但不限于以下一项或多项：终端设备确定服务小区的信号质量小于或等于第一阈值或者邻小区的信号质量大于或等于第二阈值；或者，在预设时长内，终端设备检测到服务小区的信号质量持续低于邻小区的信号质量；或者，终端设备接收到源接入网设备发送的测量控制命令；或者，终端设备所属的发送器地址(Transmitter Address，TA)发生变化。可以理解的是，本公开实施例对第一阈值、第二阈值、以及预设时长不作限制，可以根据需求进行设置。
S302、源接入网设备基于测量报告信息确定执行切换(Handover decision)。
在一些实施例中，源接入网设备根据终端设备上报的测量报告信息判断是否需要为终端设备切换RAN设备。
示例性地，若源接入网设备基于测量报告信息确定服务小区的信号质量不满足需要时，则根据无线资源管理信息确定一个RAN设备作为终端设备切换的目标接入网设备。例如，源接入网设备可以根据一个或者多个邻小区的信号质量选择一个信号质量大于或等于第二阈值的邻小区所属的RAN设备作为终端设备切换的目标接入网设备。
S303、源接入网设备向目标接入网设备发送切换请求消息(Handover Request message)。
相应地，目标接入网设备接收来自源接入网设备的切换请求消息。
该切换请求消息可以用于请求将终端设备切换至目标接入网设备。源接入网设备通过Xn接口向目标接入网设备发送切换请求消息。
在一些实施例中，该切换请求信息包括以下信息中的一项或多项：切换原因、目标小区标识、切换限制列表、以及终端设备对应的临时标识、终端设备选择的一个或者多个或者全部网络切片分别对应的网络切 片标识、终端设备选择的一个或者多个或者全部网络切片分别对应的需要建立的无线承载信息、终端设备选择的一个或者多个或者全部网络切片分别对应的需要建立的会话信息、终端设备选择的一个或者多个或者全部网络切片分别对应的需要建立的流信息。
切换原因，用于指示此次切换的原因。目标小区标识，用于唯一指示目标小区的标识。切换限制列表，包含服务公共陆地移动网络(Public Land Mobile Network，PLMN)、等效PLMN以及禁止的服务区等。终端设备对应的临时标识，用于CN设备查找保存的终端设备的上下文(UE context)。无线承载信息包括但不限于以下一项或多项：无线承载标识、无线承载级别的QoS参数、隧道终结点、或者无线承载对应的用户面安全信息。会话信息，包括但不限于以下一项或多项：会话标识、会话级别的QoS参数、隧道终结点、或会话对应的用户面安全信息。流信息，包括但不限于以下一项或多项：流标识、流级别的QoS参数、隧道终结点、或流对应的用户面安全信息。
可以理解的是，上述切换请求信息包括的内容仅为示例，还可以包括其他的信息(例如下行SN状态(DL SN Status)信息)，本公开对此不作限制。
S304、响应于切换请求消息，目标接入网设备执行准入控制(Admission Control)。
可以理解的是，目标接入网设备执行准入控制表明该目标接入网设备已经准备好了资源，做好了预切换准备。
在一些实施例中，S304例如实现为：响应于切换请求消息，若目标接入网设备允许进行网络切换，则目标接入网设备执行准入控制。
示例性地，响应于切换请求消息，则目标接入网设备根据自身对终端设备在源接入网设备所通信的网络切片的流/会话/无线承载的支持能力、资源情况以及重映射策略信息等对终端设备进行准入控制。
例如，如果目标接入网设备确定可以满足终端设备在源接入网设备所通信的网络切片的流/会话/无线承载的支持能力、资源情况以及重映射策略信息等信息，则目标接入网设备执行准入控制(Admission Control)，否则目标接入网设备向源接入网设备发送拒绝将终端设备切换至目标接入网设备的指示信息。例如，如果目标接入网设备确定可以满足终端设备所需要的无线资源要求，则目标接入网设备对终端设备进行准入控制。
S305、目标接入网设备响应于该切换请求信息，向移动性管理功能网元发送路径预切换请求信息。
路径预切换请求信息包括目标接入网设备的隧道信息。
在一些实施例中，目标接入网设备的隧道信息包括以下信息的一种或多种：目标接入网设备的身份标识、申请时间戳、隧道类型、隧道带宽、隧道地址、以及隧道优先级；目标接入网设备的身份标识用于识别目标接入网设备。
S306、移动性管理功能网元接收来自于目标接入网设备的路径预切换请求信息。
在一些实施例中，移动性管理功能网元基于路径预切换请求信息获取目标接入网设备的隧道信息。
S307、移动性管理功能网元向会话管理功能网元发送目标接入网设备的隧道信息。
在一些实施例中，S307例如实现为：移动性管理功能网元向会话管理功能网元发送更新PDU会话上下文的请求(Nsmf_PDUSession_UpdateSMContext Request)消息，该Nsmf_PDUSession_UpdateSMContext Request信息中包括目标接入网设备的隧道信息。
在一些实施例中，PDU会话上下文包括：PDU会话使用的IP(Internet Protocol)地址、接入点名字(Access Point Name，APN)、会话管理功能网元地址、以及用户面功能网元地址信息。
S308、会话管理功能网元从移动性管理功能网元获取目标接入网设备的隧道信息。
在一些实施例中，S308例如实现为：会话管理功能网元获取移动性管理功能发送的Nsmf_PDUSession_UpdateSMContext Request信息，并基于该Nsmf_PDUSession_UpdateSMContext Request信息，获取目标接入网设备的隧道信息。
S309、会话管理功能网元向用户面功能网元发送目标接入网设备的隧道信息。
在一些实施例中，上述S309例如实现为：会话管理功能网元向用户面功能网元发送N4会话修改请求(N4 Session Modify Request)。
上述N4会话修改请求包括目标接入网设备的隧道信息。该N4会话修改请求用于建立会话管理功能网元与用户面功能网元的连接。
在一些实施例中，会话管理功能网元还向用户面功能网元发送冗余传输规则，该冗余传输规则用于配置用户面功能网元向目标接入网设备和源接入网设备发送第一报文。第一报文已在上文详细描述，这里不再赘述。
S310、用户面功能网元从会话管理功能网元获取到目标接入网设备的隧道信息。
在一些实施例中，用户面功能网元在获取到目标接入网设备的隧道信息后，安装下行冗余转发器，以使得在第一传输隧道建立完成后用户面功能网元可以同时向源接入网设备和目标接入网设备发送相同的第一报文。
在一些实施例中，上述第一报文还包括冗余传输标识。
S311、用户面功能网元向会话管理功能网元发送S309的响应信息。
在一些实施例中，S311例如实现为：用户面功能网元向会话管理功能网元发送N4会话修改请求响应信息。
S312、响应于用户面功能网元发送的上述S309的响应信息，会话管理功能网元向移动性管理功能网元发送上述S307的响应信息。
在一些实施例中，S312例如实现为：在接收到用户面功能网元发送的上述S309响应信息后，会话管理功能网元向移动性管理功能网元发送上述更新PDU会话上下文的请求的响应信息。
S313、响应于会话管理功能网元发送的上述S307的响应信息，移动性管理功能网元向目标接入网设备发送上述S305的响应信息。
示例性地，S313例如实现为：响应于会话管理功能网元发送的上述S307的响应信息后，移动性管理功能网元向目标接入网设备发送路径预切换请求信息的响应信息。可以理解的是，在S313之后，第一传输隧道建立完成。
在一些实施例中，在第一传输隧道建立完成后，用户面功能网元通过第一传输隧道向目标接入网设备发送第一报文。相应地，目标接入网设备还可以缓存该第一报文。
在一些实施例中，用户面功能网元与源接入网设备之间还存在第二传输隧道，在第一传输隧道建立完成后，用户面功能网元还基于第二传输隧道向源接入网设备发送相同的第一报文。可以理解的是，第二传输隧道是源接入网设备与用户面功能网元预先建立的。
S314、在第一传输隧道建立完成后，目标接入网设备向源接入网设备发送切换请求确认消息(Handover Request Acknowledge message)。
可以理解的是，S314是对S303的响应。
切换请求确认消息可以用于指示目标接入网设备允许将终端设备切换至目标接入网设备。
S315、响应于切换请求确认消息，源接入网设备通知终端设备准备切换接入网设备。
S316、源接入网设备向目标接入网设备发送状态转移信息(SN STATUS TRANSFER information)。
在一些实施例中，上述状态转移信息包括源接入网设备的第二报文的序列号，以便目标接入网设备获知源接入网设备已经发送的报文情况。该第二报文为源接入网设备通过第二传输隧道接收到的第一报文中，源接入网设备已成功发送给终端设备的报文。
S317、目标接入网设备接收源接入网设备发送的状态转移信息。
在一些实施例中，在上述状态转移信息包括源接入网设备的第二报文的序列号的情况下，目标接入网设备可以基于该序列号从缓存的第一报文中排除终端设备已经收到的报文，避免重复发送，提高通信的效率和可靠性。
可以理解的是，在S317之后，目标接入网设备已经可以向终端设备发送来自第一传输隧道的第一报文。
S318、目标接入网设备向移动性管理功能网元发送第一切换完成确认信息。
在一些实施例中，上述第一切换完成确认信息用于指示终端设备端的路径切换完成。
在一些实施例中，上述第一切换完成确认信息还用于请求结束冗余传输。
在一些实施例中，上述第一切换完成确认信息还用于请求释放源接入网设备的用于传输终端设备的下行报文的资源。
S319、移动性管理功能网元接收到第一切换完成确认信息后，向会话管理功能网元发送第一切换完成确认信息。
在一些实施例中，上述S319例如实现为：移动性管理功能网元接收到第一切换完成确认信息后，向会话管理功能网元发送更新PDU会话上下文的请求消息，该更新PDU会话上下文的请求信息中包括上述第一切换完成确认信息。
S320、会话管理功能网元接收到第一切换完成确认信息后，向用户面功能网元发送第一切换完成确认信息。
在一些实施例中，上述S320例如实现为：会话管理功能网元接收到第一切换完成确认信息后，向用户面功能网元发送N4会话修改请求，该N4会话修改请求包括第一切换完成确认信息。
S321、用户面功能网元接收到第一切换完成确认信息后，向会话管理功能网元发送第二切换完成确认信息。
在一些实施例中，上述S321例如实现为：用户面功能网元接收到第一切换完成确认信息后，向会话管理功能网元发送N4会话修改请求响应信息，该N4会话修改请求响应信息包括第二切换完成确认消息。
在一些实施例中，第二切换完成确认消息用于指示释放源接入网设备的用于传输终端设备的下行报文的资源。例如，第二切换完成确认消息可以用于指示释放源接入网设备与用户面功能网元的第二传输隧道，或者释放源接入网设备内尚未发送的包括冗余传输标识的第一报文等。
在一些实施例中，用户面功能网元接收到上述第一切换完成确认信息后，若第一切换完成确认信息还用于请求结束冗余传输，则结束冗余传输，通过第一传输隧道向目标接入网设备发送未携带冗余传输标识的第四报文。
S322、会话管理功能网元接收到第二切换完成确认信息后，向移动性管理功能网元发送第二切换完成确认信息。
在一些实施例中，上述S322例如实现为：会话管理功能网元接收到第二切换完成确认信息后，向移动性管理功能网元发送更新PDU会话上下文的请求的响应信息，该更新PDU会话上下文的请求的响应信息包括第二切换完成确认消息。
S323、移动性管理功能网元接收到第二切换完成确认信息后，向目标接入网设备发送第二切换完成确认信息。
S324、目标接入网设备接收到切换完成确认消息后，向源接入网设备发送第二切换完成确认消息。
相应地，源接入网设备接收到切换确认消息后，释放自身资源，不再作为终端设备的接入网设备与用户面功能网元进行报文传输。
需要说明的是，上述图7所示的实施例是以目标接入网设备和源接入网设备属于同一个AMF网元为例的，在实际过程中，源接入网设备和目标接入网设备可以属于不同的AMF网元，本公开对此不作限制。
此外，图8示出了本公开实施例提供的另一种切换方法。下面以基于N2接口的切换为例进行描述，参照图8，例如如下所述。
S401、源接入网设备向移动性管理功能网元发送切换请求消息。
该切换请求消息中可以包括目标接入网设备的标识，源到目标容器(例如，Target To Source Transparent Container)，会话管理(Session Management，SM)N2信息列表，PDU会话标识，系统内部切换指示。
目标接入网设备的标识用于识别目标接入网设备。
源到目标容器，包括目标接入网设备使用的接入网信息，该源到目标容器中所携带的信息不被核心网所感知。可以将源到目标容器理解为源接入网设备发送给目标接入网设备的一个容器，该容器中的详细内容在中间的网元不进行识别和处理，可以直接传给目标接入网设备，目标接入网设备在接收到源到目标容器后可以解析里面的内容。
SM N2信息列表包括直接转发路径是否可用指示。
系统内部切换指示用于指示该切换为5G内部的切换。
在一些实施例中，在执行S401之前，还包括以下步骤：源接入网设备确定发起N2的切换流程。示例性地，若终端设备的服务小区的信号质量不满足需要时，则源接入网设备确定发起N2的切换流程。例如，该过程可参照上述S301至S302所示的确定执行切换的过程，在此不予赘述。
S402、移动性管理功能网元响应于切换请求消息，向会话管理功能网元发送更新PDU会话上下文的请求消息。
在一些实施例中，该PDU会话上下文的请求消息中可以包括SM N2信息列表，SM N2信息列表用于指示直接转发路径是否可用。
作为一种示例，若移动性管理功能网元能够为终端设备提供服务，则直接执行上述S402。在一些实施例中，可以根据目标接入网设备的标识确定是否能为终端设备提供服务。例如，移动性管理功能网元基于目标接入网设备的标识，判断目标接入网设备是否由该移动性管理功能网元管理；若目标接入网设备被该移动性管理功能网元管理，则该移动性管理功能网元能够为终端设备服务，否则，该移动性管理功能网元不能够为终端设备服务。
作为又一种示例，若移动性管理功能网元不能为终端设备服务，则移动性管理功能网元响应于切换请求消息，移动性管理功能网元为终端设备选择一个目标移动管理网元。示例性地，根据目标接入网设备的标识，选择与目标接入网设备连接的其他移动性管理功能网元作为目标移动性管理功能网元。进一步地，S402例如实现为：目标移动管理网元响应于切换请求消息，向会话管理功能网元发送更新PDU会话上下文的请求消息。
S403、会话管理功能网元响应于更新PDU会话上下文的请求消息，确定是否允许N2切换。
在一些实施例中，上述会话管理功能网元基于目标接入网设备的标识，确定是否允许N2切换。示例性 地，如果会话管理功能网元确定终端设备的会话业务不能在目标接入网设备的标识所指示的目标接入网设备的目标小区进行传输时，则不允许N2切换。例如，有些业务只能在特定的区域才能访问，如校园网，用户离开校园便不能访问。
S404、若允许N2切换，会话管理功能网元向用户面功能网元发送N4会话建立请求(N4 Session Establish Request)。
该N4会话建立请求可以用于建立用户面连接，该N4会话建立请求中可以携带用户面的隧道信息。
S405、响应于N4会话建立请求，用户面功能网元向会话管理功能网元发送N4会话建立请求的响应信息。
S406、响应于N4会话建立请求的响应信息，会话管理功能网元向移动性管理功能网元发送PDU会话上下文的请求消息的响应信息。
S407、响应于PDU会话上下文的请求消息的响应信息，移动性管理功能网元向目标接入网设备发送切换请求信息。
该切换请求消息可以用于请求将终端设备切换至目标接入网设备。移动性管理功能网元通过N2接口向目标接入网设备发送切换请求消息。切换请求信息所包括的内容可以参考上述S303的描述，在此不再赘述。
S408、目标接入网设备响应于该切换请求信息，向移动性管理功能网元发送目标接入网设备的隧道信息。
在一些实施例中，S408例如实现为：目标接入网设备响应于该切换请求信息，向移动性管理功能网元发送切换请求的响应信息。切换请求响应信息包括路径预切换请求信息，且路径预切换请求信息包括目标接入网设备的隧道信息。
或者，目标接入网设备响应于该切换请求信息，向移动性管理功能网元发送路径预切换请求信息，路径预切换请求信息包括目标接入网设备的隧道信息。
目标接入网设备的隧道信息包括以下信息的一种或多种：目标接入网设备的身份标识、申请时间戳、隧道类型、隧道带宽、隧道地址、以及隧道优先级；目标接入网设备的身份标识用于识别目标接入网设备。
S409、移动性管理功能网元从目标接入网设备获取目标接入网设备的隧道信息。
在一些实施例中，移动性管理功能网元基于路径预切换请求信息获取目标接入网设备的隧道信息。
S410、响应于从目标接入网设备获取目标接入网设备的隧道信息，移动性管理功能网元向会话管理功能网元发送目标接入网设备的隧道信息。
在一些实施例中，S410例如实现为：移动性管理功能网元向会话管理功能网元发送更新PDU会话上下文的请求消息，该更新PDU会话上下文的请求信息中包括目标接入网设备的隧道信息。
在一些实施例中，PDU会话上下文包括：PDU会话使用的IP(Internet Protocol)地址、接入点名字(Access Point Name，APN)、会话管理功能网元地址、以及用户面功能网元地址信息。
S411、会话管理功能网元从移动性管理功能网元获取目标接入网设备的隧道信息。
在一些实施例中，上述S411，例如实现为：会话管理功能网元获取移动管理发送的更新PDU会话上下文的请求信息，并基于该更新PDU会话上下文的请求信息，获取目标接入网设备的隧道信息。
S412、会话管理功能网元向用户面功能网元发送目标接入网设备的隧道信息。
在一些实施例中，上述S412例如实现为：会话管理功能网元向用户面功能网元发送N4会话修改请求(N4 Session Modify Request)。
上述N4会话修改请求包括目标接入网设备的隧道信息。该N4会话修改请求用于建立会话管理功能网 元与用户面功能网元的连接。
在一些实施例中，会话管理功能网元还向用户面功能网元发送冗余传输规则，该冗余传输规则用于配置用户面功能网元向目标接入网设备和源接入网设备发送第一报文。第一报文已在上文详细描述，在此不再赘述。
S413、用户面功能网元从会话管理功能网元获取到目标接入网设备的隧道信息。
在一些实施例中，用户面功能网元在获取到目标接入网设备的隧道信息后，安装下行冗余转发器，以使得在第一传输隧道建立完成后用户面功能网元可以同时向源接入网设备和目标接入网设备发送相同的第一报文。
在一些实施例中，上述第一报文还包括冗余传输标识。
S414、用户面功能网元向会话管理功能网元发送S412的响应信息。
在一些实施例中，S414例如实现为：用户面功能网元向会话管理功能网元发送N4会话修改请求响应信息。
S415、响应于用户面功能网元发送的上述S412的响应信息，会话管理功能网元向移动性管理功能网元发送上述S410的响应信息。
在一些实施例中，S415例如实现为：在接收到用户面功能网元发送的上述S412响应信息后，会话管理功能网元向移动性管理功能网元发送上述更新PDU会话上下文的请求的响应信息。
可以理解的是，在S415之后，第一传输隧道建立完成。
在一些实施例中，在第一传输隧道建立完成后，用户面功能网元通过第一传输隧道向目标接入网设备发送第一报文。相应地，目标接入网设备还可以缓存该第一报文。
在一些实施例中，用户面功能网元与源接入网设备之间还存在第二传输隧道，在第一传输隧道建立完成后，用户面功能网元还基于第二传输隧道向源接入网设备发送相同的第一报文。
S416、在第一传输隧道建立完成后，移动性管理功能网元向源接入网设备发送切换命令。
切换请求命令可以用于指示将终端设备从源接入网设备切换至目标接入网设备。
S417、响应于切换命令，源接入网设备通知终端设备准备切换接入网设备。
S418、在源接入网设备通知终端设备准备切换接入网设备后，终端设备向目标接入网设备发送第一切换完成确认信息。
在一些实施例中，上述第一切换完成确认信息用于指示终端设备端的路径切换完成。
在一些实施例中，上述第一切换完成确认信息还用于请求结束冗余传输。
在一些实施例中，上述第一切换完成确认信息还用于请求释放源接入网设备的用于传输终端设备的下行报文的资源。
S419、响应于终端设备发送的第一切换完成确认信息，目标接入网设备向移动性管理功能网元发送第一切换完成确认信息，以告知移动性管理功能网元切换完成。
S420、移动性管理功能网元接收到发送的第一切换完成确认信息后，向会话管理功能网元发送第一切换完成确认信息。
在一些实施例中，上述S420例如实现为：移动性管理功能网元接收到第一切换完成确认信息后，向会话管理功能网元发送更新PDU会话上下文的请求消息，该更新PDU会话上下文的请求信息中包括第一切换完成确认信息。
S421、会话管理功能网元接收到第一切换完成确认信息后，向用户面功能网元发送第一切换完成确认 信息。
在一些实施例中，上述S421例如实现为：会话管理功能网元接收到第一切换完成确认信息后，向用户面功能网元发送N4会话修改请求，该N4会话修改请求包括第一切换完成确认信息。
S422、用户面功能网元接收到第一切换完成确认信息后，向会话管理功能网元发送第二切换完成确认信息。
在一些实施例中，上述S422例如实现为：用户面功能网元接收到第一切换完成确认信息后，向会话管理功能网元发送N4会话修改请求响应信息，该N4会话修改请求响应信息包括第二切换完成确认消息。
在一些实施例中，第二切换完成确认消息用于指示释放源接入网设备的用于传输终端设备的下行报文的资源。例如，第二切换完成确认消息可以用于指示释放源接入网设备与用户面功能网元的第二传输隧道，或者释放源接入网设备内尚未发送的包括冗余传输标识的第一报文等。
在一些实施例中，用户面功能网元接收到上述第一切换完成确认信息后，若第一切换完成确认信息还用于请求结束冗余传输，则结束冗余传输，通过第一传输隧道向目标接入网设备发送未携带冗余传输标识的第四报文。
S423、会话管理功能网元接收到第二切换完成确认信息后，向移动性管理功能网元发送第二切换完成确认信息。
在一些实施例中，上述S423例如实现为：会话管理功能网元接收到第二切换完成确认信息后，向移动性管理功能网元发送更新PDU会话上下文的请求的响应信息，该更新PDU会话上下文的请求的响应信息包括第二切换完成确认消息。
相应地，移动性管理功能网元接收到第二切换完成确认信息后，释放源接入网设备的资源。
可以看出，在S423之后，基于N2接口的切换已经完成，终端设备的接入网设备已经转为目标接入网设备。
上述主要从各个网元之间交互的角度对本公开实施例的方案进行了介绍。可以理解的是，各个网元，例如切换装置等为了实现上述功能，切换装置包含了执行各个功能相应的硬件结构和/或软件模块。本领域技术人员应该很容易意识到，结合本文中所公开的实施例描述的各示例的单元及算法步骤，本公开能够以硬件或硬件和计算机软件的结合形式来实现。某个功能究竟以硬件还是计算机软件驱动硬件的方式来执行，取决于技术方案的特定应用和设计约束条件。专业技术人员可以对每个特定的应用来使用不同方法来实现所描述的功能。
本公开实施例可以根据上述方法示例对切换装置进行功能单元的划分，例如，可以对应各个功能划分各个功能单元，也可以将两个或两个以上的功能集成在一个处理单元中。上述集成的单元既可以采用硬件的形式实现，也可以采用软件功能单元的形式实现。需要说明的是，本公开实施例中对单元的划分是示意性的，仅仅为一种逻辑功能划分，实际实现时可以有另外的划分方式。
下面以采用对应各个功能划分各个功能模块为例进行说明。
图9为根据一些实施例的目标接入网设备的结构示意图，结构也可以适用于目标接入网设备中的芯片，用于执行上述各方法实施例中目标接入网设备，或T-RAN设备的动作。
如图9所示，目标接入网设备300包括第一传输隧道建立模块301和第一报文处理模块302。
第一传输隧道建立模块301，用于在终端设备从源接入网设备切换到目标接入网设备的切换准备过程中，与用户面功能网元建立第一传输隧道。
第一报文处理模块302，用于通过第一传输隧道接收并缓存第一报文，第一报文为待发送给终端设备的 报文。
在一些实施例中，上述第一报文携带有冗余传输标识。
在一些实施例中，上述第一传输隧道建立模块301，用于向移动性管理功能网元发送目标接入网设备的隧道信息，目标接入网设备的隧道信息用于建立第一传输隧道。
在一些实施例中，上述第一传输隧道建立模块301，还用于接收来自于源接入网设备的切换请求信息；上述第一传输隧道建立模块301，用于响应于切换请求信息，向移动性管理功能网元发送路径预切换请求信息，路径预切换请求信息包括目标接入网设备的隧道信息。
在一些实施例中，上述第一传输隧道建立模块301，还用于接收来自于移动性管理功能网元的路径预切换请求响应信息。
在一些实施例中，上述第一传输隧道建立模块301，还用于接收来自于移动性管理功能网元的切换请求信息；上述第一传输隧道建立模块301，用于响应于切换请求信息，向移动性管理功能网元发送切换请求响应信息，切换请求响应信息包括目标接入网设备的隧道信息。
在一些实施例中，上述第一报文处理模块302还用于与终端设备建立通信连接。通过与终端设备之间的通信连接，第一报文处理模块302向终端设备发送第一报文。
在一些实施例中，上述第一报文处理模块302用于从第一报文中排除第二报文，得到第三报文；第二报文为源接入网设备通过第二传输隧道接收到的第一报文中，源接入网设备已成功发送给终端设备的报文。通过与终端设备之间的通信连接，第一报文处理模块302向终端设备发送第三报文。
在一些实施例中，上述第一报文处理模块302用于目标接入网设备接收来自于源接入网设备的第二报文的序列号；目标接入网设备基于第二报文的序列号，从第一报文中排除第二报文，得到第三报文。
在一些实施例中，上述第一报文处理模块302还用于在切换完成之后通过第一传输隧道接收未携带冗余传输标识的第四报文；目标接入网设备向终端设备发送第四报文。
图10为根据一些实施例的移动性管理功能网元的结构示意图，用于执行上述各方法实施例中移动性管理功能网元的动作。
如图10所示，移动性管理功能网元500包括第一获取模块501和第一发送模块502。
第一获取模块501用于在终端设备从源接入网设备切换到目标接入网设备的切换准备过程中，从目标接入网设备获取目标接入网设备的隧道信息，目标接入网设备的隧道信息用于建立目标接入网设备与用户面功能网元之间的第一传输隧道。
第一发送模块502用于向会话管理功能网元发送目标接入网设备的隧道信息。
在一些实施例中，第一获取模块501用于接收来自于目标接入网设备的路径预切换请求信息，路径预切换请求信息包括目标接入网设备的隧道信息。
在一些实施例中，第一发送模块502还用于向目标接入网设备发送路径预切换请求响应信息。
在一些实施例中，第一发送模块502还用于向目标接入网设备发送切换请求信息；第一获取模块501用于接收来自于目标接入网设备的切换请求响应信息，切换请求响应信息包括目标接入网设备的隧道信息。
图11为根据一些实施例的会话管理功能网元的结构示意图，用于执行上述各方法实施例中会话管理功能网元的动作。
如图11所示，会话管理功能网元600包括第二获取模块601和第二发送模块602。
第二获取模块601用于在终端设备从源接入网设备切换到目标接入网设备的切换准备过程中，从移动性管理功能网元获取目标接入网设备的隧道信息，目标接入网设备的隧道信息用于建立目标接入网设备与 用户面功能网元之间的第一传输隧道。
第二发送模块602用于向用户面功能网元发送目标接入网设备的隧道信息。
在一些实施例中，上述会话管理功能网元600还包括冗余配置模块603。该冗余配置模块603，用于为用户面功能网元配置冗余传输规则。该冗余传输规则用于配置用户面功能网元向目标接入网设备和源接入网设备发送第一报文。该第一报文为待发送给终端设备的报文。
在一些实施例中，上述第一报文携带有冗余传输标识。
在一些实施例中，上述第二发送模块602还用于在终端设备从源接入网设备切换到目标接入网设备的切换执行过程中，向用户面管理功能网元发送用于指示停止冗余传输的指示信息。图12为根据一些实施例的用户面功能网元的结构示意图，用于执行上述各方法实施例中用户面功能网元的动作。
如图12所示，用户面功能网元700包括第二隧道建立模块701和第二报文处理模块702。
第二隧道建立模块701用于在终端设备从源接入网设备切换到目标接入网设备的切换准备过程中，与目标接入网设备建立第一传输隧道。
第二报文处理模块702用于通过第一传输隧道向目标接入网设备发送第一报文，第一报文为待发送给终端设备的报文。
在一些实施例中，上述第二隧道建立模块701用于从会话管理功能网元获取到目标接入网设备的隧道信息，目标接入网设备的隧道信息用于建立目标接入网设备与用户面功能网元之间的第一传输隧道。
在一些实施例中，上述第二报文处理模块702还用于接收会话管理功能网元发送的冗余传输规则。该冗余传输规则用于配置用户面功能网元向目标接入网设备和源接入网设备发送第一报文，第一报文为待发送给终端设备的报文。
在一些实施例中，上述第二报文处理模块702还用于通过第二传输隧道向源接入网设备发送第一报文。
在一些实施例中，上述第一报文携带有冗余传输标识。
在一些实施例中，上述第二报文处理模块702还用于在终端设备从源接入网设备切换到目标接入网设备的切换执行过程中，接收会话管理功能网元发送用于指示停止冗余传输的指示信息；基于指示信息，通过第一传输隧道向目标接入网设备发送未携带冗余传输标识的第四报文。
在采用硬件的形式实现上述集成的模块的功能的情况下，本公开实施例提供了上述实施例中所涉及的目标接入网设备、移动性管理功能网元、会话管理功能网元、以及用户面功能网元的另一种可能的结构。如图13所示，该通信节点400包括：处理器402和总线404。在一些实施中，该通信节点400还可以包括存储器401。在一些实施例中，该通信节点400还可以包括通信接口403。
处理器402，可以是实现或执行结合本公开实施例所描述的各种示例性的逻辑方框、模块和电路。该处理器402可以是中央处理器、通用处理器、数字信号处理器、专用集成电路、现场可编程门阵列或者其他可编程逻辑器件、晶体管逻辑器件、硬件部件或者其任意组合。该处理器402可以实现或执行结合本公开实施例所描述的各种示例性的逻辑方框，模块和电路。处理器402也可以是实现计算功能的组合，例如包含一个或多个微处理器组合，DSP和微处理器的组合等。
通信接口403，用于与其他设备通过通信网络连接。该通信网络可以是以太网、无线接入网、无线局域网(Wireless Local Area Networks，WLAN)等。
存储器401，可以是只读存储器(Read-Only Memory，ROM)或可存储静态信息和指令的其他类型的静态存储设备，随机存取存储器(Random Access Memory，RAM)或者可存储信息和指令的其他类型的动态存储设备，也可以是电可擦可编程只读存储器(Electrically Erasable Programmable Read-Only Memory， EEPROM)、磁盘存储介质或者其他磁存储设备、或者能够用于携带或存储具有指令或数据结构形式的期望的程序代码并能够由计算机存取的任何其他介质，但不限于此。
作为一种示例，存储器401可以独立于处理器402存在，存储器401可以通过总线404与处理器402相连接，用于存储指令或者程序代码。处理器402调用并执行存储器401中存储的指令或程序代码时，能够实现本公开实施例提供的切换方法。
作为另一种示例，存储器401也可以和处理器402集成在一起。
总线404，可以是扩展工业标准结构(Extended Industry Standard Architecture，EISA)总线等。总线404可以分为地址总线、数据总线、控制总线等。为便于表示，图13中仅用一条粗线表示，但并不表示仅有一根总线或一种类型的总线。
本公开一些实施例提供了一种计算机可读存储介质(例如，非暂态计算机可读存储介质)，该计算机可读存储介质中存储有计算机程序指令，计算机程序指令在计算机上运行时，使得计算机执行如上述实施例中任一实施例所述的切换方法。在一些实施例中，该计算机可以为上述通信节点或该通信节点中的处理器。
示例性地，上述计算机可读存储介质可以包括，但不限于：磁存储器件(例如，硬盘、软盘或磁带等)，光盘(例如，压缩盘(Compact Disk，CD)、数字通用盘(Digital Versatile Disk，DVD)等)，智能卡和闪存器件(例如，可擦写可编程只读存储器(Erasable Programmable Read-Only Memory，EPROM)、卡、棒或钥匙驱动器等)。本公开实施例描述的各种计算机可读存储介质可代表用于存储信息的一个或多个设备和/或其它机器可读存储介质。术语“机器可读存储介质”可包括但不限于，无线信道和能够存储、包含和/或承载指令和/或数据的各种其它介质。
本公开实施例提供一种包含指令的计算机程序产品，当该计算机程序产品在计算机上运行时，使得该计算机执行上述实施例中任一实施例所述的切换方法。
以上所述，仅为本公开的具体实施方式，但本公开的保护范围并不局限于此，任何在本公开揭露的技术范围内的变化或替换，都应涵盖在本公开的保护范围之内。因此，本公开的保护范围应该以权利要求的保护范围为准。

Claims (26)

  1. 一种切换方法，包括：
    在终端设备从源接入网设备切换到目标接入网设备的切换准备过程中，所述目标接入网设备与用户面网元建立第一传输隧道；
    所述目标接入网设备通过所述第一传输隧道接收并缓存第一报文，所述第一报文为待发送给所述终端设备的报文。
  2. 根据权利要求1所述的方法，其中，所述第一报文携带有冗余传输标识。
  3. 根据权利要求1所述的方法，其中，所述目标接入网设备与用户面网元建立第一传输隧道，包括：
    所述目标接入网设备向移动管理网元发送所述目标接入网设备的隧道信息，所述目标接入网设备的隧道信息用于建立所述第一传输隧道。
  4. 根据权利要求3所述的方法，还包括：
    所述目标接入网设备接收来自于所述源接入网设备的切换请求信息；
    所述目标接入网设备向移动管理网元发送所述目标接入网设备的隧道信息，包括：
    所述目标接入网设备响应于所述切换请求信息，向所述移动管理网元发送路径预切换请求信息，所述路径预切换请求信息包括所述目标接入网设备的隧道信息。
  5. 根据权利要求4所述的方法，还包括：
    所述目标接入网设备接收来自于所述移动管理网元的路径预切换请求响应信息。
  6. 根据权利要求3所述的方法，还包括：
    所述目标接入网设备接收来自于所述移动管理网元的切换请求信息；
    所述目标接入网设备向移动管理网元发送所述目标接入网设备的隧道信息，包括：
    所述目标接入网设备响应于所述切换请求信息，向所述移动管理网元发送切换请求响应信息，所述切换请求响应信息包括所述目标接入网设备的隧道信息。
  7. 根据权利要求1至6任一项所述的方法，还包括：
    所述目标接入网设备与所述终端设备建立通信连接；
    所述目标接入网设备通过与所述终端设备之间的通信连接，向所述终端设备发送所述第一报文。
  8. 根据权利要求7所述的方法，其中，所述目标接入网设备通过与所述终端设备之间的通信连接，向所述终端设备发送所述第一报文，包括：
    所述目标接入网设备从所述第一报文中排除第二报文，得到第三报文；其中，所述第二报文为所述源接入网设备通过第二传输隧道接收到的第一报文中，所述源接入网设备已成功发送给所述终端设备的报文；
    所述目标接入网设备通过与所述终端设备之间的通信连接，向所述终端设备发送所述第三报文。
  9. 根据权利要求8所述的方法，其中，所述目标接入网设备从所述第一报文中排除第二报文，得到第三报文，包括：
    所述目标接入网设备接收来自于所述源接入网设备的所述第二报文的序列号；
    所述目标接入网设备基于所述第二报文的序列号，从所述第一报文中排除所述第二报文，得到所述第三报文。
  10. 根据权利要求7所述的方法，还包括：
    所述目标接入网设备在切换完成之后通过所述第一传输隧道接收未携带冗余传输标识的第四报文；
    所述目标接入网设备向所述终端设备发送所述第四报文。
  11. 一种切换方法，包括：
    在终端设备从源接入网设备切换到目标接入网设备的切换准备过程中，移动管理网元从所述目标接入网设备获取所述目标接入网设备的隧道信息，所述目标接入网设备的隧道信息用于建立所述目标接入网设备与用户面网元之间的第一传输隧道；
    所述移动管理网元向会话管理网元发送所述目标接入网设备的隧道信息。
  12. 根据权利要求11所述的方法，其中，所述移动管理网元从所述目标接入网设备获取所述目标接入网设备的隧道信息，包括：
    所述移动管理网元接收来自于所述目标接入网设备的路径预切换请求信息，所述路径预切换请求信息包括所述目标接入网设备的隧道信息。
  13. 根据权利要求12所述的方法，还包括：
    所述移动管理网元向所述目标接入网设备发送所述路径预切换请求响应信息。
  14. 根据权利要求11所述的方法，还包括：
    所述移动管理网元向所述目标接入网设备发送切换请求信息；
    所述移动管理网元从所述目标接入网设备获取所述目标接入网设备的隧道信息，包括：
    所述移动管理网元接收来自于所述目标接入网设备的切换请求响应信息，所述切换请求响应信息包括所述目标接入网设备的隧道信息。
  15. 一种切换方法，包括：
    在终端设备从源接入网设备切换到目标接入网设备的切换准备过程中，会话管理网元从移动管理网元获取所述目标接入网设备的隧道信息，所述目标接入网设备的隧道信息用于建立所述目标接入网设备与用户面网元之间的第一传输隧道；
    所述会话管理网元向所述用户面网元发送所述目标接入网设备的隧道信息。
  16. 根据权利要求15所述的方法，还包括：
    所述会话管理网元为所述用户面网元配置冗余传输规则，所述冗余传输规则用于配置所述用户面网元向所述目标接入网设备和所述源接入网设备发送第一报文，所述第一报文为待发送给终端设备的报文。
  17. 根据权利要求15所述的方法，其中，所述第一报文携带有冗余传输标识。
  18. 根据权利要求16或17任一项所述的方法，还包括：
    在所述终端设备从所述源接入网设备切换到所述目标接入网设备的切换执行过程中，所述会话管理网向所述用户面管理网元发送用于指示停止冗余传输的指示信息。
  19. 一种切换方法，包括：
    在终端设备从源接入网设备切换到目标接入网设备的切换准备过程中，用户面网元与所述目标接入网设备建立第一传输隧道；
    所述用户面网元通过所述第一传输隧道向所述目标接入网设备发送第一报文，所述第一报文为待发送给所述终端设备的报文。
  20. 根据权利要求19所述的方法，其中，所述用户面网元与所述目标接入网设备建立第一传输隧道，包括：
    所述用户面网元从会话管理网元获取到所述目标接入网设备的隧道信息，所述目标接入网设备的隧道信息用于建立所述目标接入网设备与用户面网元之间的第一传输隧道。
  21. 根据权利要求20所述的方法，还包括：
    所述用户面网元接收所述会话管理网元发送的冗余传输规则，所述冗余传输规则用于配置所述用户面网元向所述目标接入网设备和所述源接入网设备发送第一报文，所述第一报文为待发送给终端设 备的报文。
  22. 根据权利要求21所述的方法，还包括：
    所述用户面网元通过第二传输隧道向所述源接入网设备发送所述第一报文。
  23. 根据权利要求19至21任一项所述的方法，其中，所述第一报文携带有冗余传输标识。
  24. 根据权利要求23所述的方法，还包括：
    在所述终端设备从所述源接入网设备切换到所述目标接入网设备的切换执行过程中，所述用户面网元接收所述会话管理网元发送用于指示停止冗余传输的指示信息；
    所述用户面网元基于所述指示信息，通过所述第一传输隧道向所述目标接入网设备发送未携带冗余传输标识的第四报文。
  25. 一种通信节点，包括：处理器和用于存储所述处理器可执行指令的存储器；
    其中，所述处理器被配置为执行所述指令，使得所述通信节点执行如权利要求1-24中任一项所述的切换方法。
  26. 一种计算机可读存储介质，其中，所述计算机可读存储介质上存储有计算机指令，当所述计算机指令在通信节点上运行时，使得所述通信节点执行如权利要求1-24中任一项所述的切换方法。
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