WO2019007226A1 - 建立会话的方法和装置 - Google Patents

建立会话的方法和装置 Download PDF

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Publication number
WO2019007226A1
WO2019007226A1 PCT/CN2018/092760 CN2018092760W WO2019007226A1 WO 2019007226 A1 WO2019007226 A1 WO 2019007226A1 CN 2018092760 W CN2018092760 W CN 2018092760W WO 2019007226 A1 WO2019007226 A1 WO 2019007226A1
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Prior art keywords
session
tunnel
information
message
amf
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PCT/CN2018/092760
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English (en)
French (fr)
Inventor
李永翠
李岩
倪慧
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华为技术有限公司
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Publication of WO2019007226A1 publication Critical patent/WO2019007226A1/zh

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W48/00—Access restriction; Network selection; Access point selection
    • H04W48/20—Selecting an access point
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W76/00—Connection management
    • H04W76/10—Connection setup

Definitions

  • the present application relates to the field of communications, and in particular, to a method and apparatus for establishing a session in the field of wireless communications.
  • the user plane model refers to a tunnel model between an access network (AN) and a user plane function (UPF).
  • the tunnel refers to a communication path between the AN and the UPF.
  • the aggregated user plane model is one of the user plane models.
  • one tunnel corresponds to multiple sessions, and the multiple sessions may belong to one terminal device or multiple terminal devices.
  • the session is used to provide a protocol data unit (PDU) connection service for a user equipment (UE) and a data network (DN).
  • PDU protocol data unit
  • UE user equipment
  • DN data network
  • the present application provides a method and apparatus for establishing a session, which can solve the problem that the AN discards downlink data in the aggregated user plane model.
  • the first aspect provides a method for establishing a session, where the AN receives the first downlink data from the UPF, where the first downlink data includes a first UE network protocol (IP) address and first tunnel identifier information;
  • the AN sends a first message to the access and mobility management function (AMF), the first message includes a first UE IP address and first tunnel identification information;
  • the AN receives a second message from the AMF, the first
  • the second message includes a context for establishing a first session, and the first session is a session corresponding to the first UE IP address and the first tunnel identity information.
  • the AN can recover the context between the UE and the AN by sending the first UE IP address and the first tunnel identification information to the AMF, and receiving the context sent by the AMF for restoring the first session.
  • the wireless connection corresponding to the first UE IP address and the first tunnel identifier information prevents the AN from discarding the first downlink data.
  • the method further includes: the AN receiving a third message from the AMF, where the third message includes an identifier of the first session, a first correspondence between the first UE IP address and the first tunnel identity information, and a third The message further includes a second correspondence between the identifier of the second session, the second UE IP address, and the second tunnel identity information.
  • the session corresponding to the downlink data may be determined according to the second correspondence, thereby obtaining the session management function (SMF) through the AMF.
  • SMF session management function
  • the session context corresponding to the second session so that the wireless connection between the UE and the AN corresponding to the second UE IP address and the second tunnel identity information can be restored, and the AN is prevented from discarding the second downlink data.
  • the method further includes: the AN receives the second downlink data from the UPF, where the second downlink data includes the second UE IP address and the second tunnel identifier information; the AN sends a fourth message to the AMF, where the fourth message includes The identity of the second session; the AN receives a fifth message from the AMF, the fifth message including a context for establishing a second session.
  • the identifier of the second session may be determined according to the second UE IP address and the second tunnel identifier information included in the second downlink data, and the identifier of the second session is sent to the AMF, so that the AMF does not need to be And determining the identifier of the second session according to the second UE IP address and the second tunnel identifier information, and directly sending the context for restoring the second session to the AN, improving the response speed of the AMF, and reducing the burden of the AMF.
  • the method further includes: if the first UE is in an idle state, the AN sends a paging message to the first UE, where the first UE is a UE corresponding to the first UE IP address and the first tunnel identity information.
  • the AN may select a corresponding method for restoring the first session according to the current specific situation of the first UE. For example, when the first UE is in an idle state, the method may be used to restore the first session, thereby preventing the AN from discarding the first session. Row data; when the first UE is in the connected state, the AN can directly obtain the session context corresponding to the first session by using the AMF to the SMF corresponding to the first session, thereby restoring the air interface connection between the AN corresponding to the first session and the first UE. To avoid the user experience degradation caused by the AN discarding the first downlink data.
  • the first tunnel identifier information is at least one of a tunnel identifier, tunnel information on the AN side, and tunnel information on the UPF side.
  • the method further includes: the AN sending the first downlink data to the first UE by using the first session, where the first UE is a UE corresponding to the first UE IP address and the first tunnel identifier information.
  • a second aspect provides a method for establishing a session, including: receiving, by an AMF, a first message from an AN, where the first message includes a first UE IP address and first tunnel identification information; and the AMF sends a second message to the AN, where the The second message includes a context for establishing a first session, the first session being a session corresponding to the first UE IP address and the first tunnel identity information.
  • the AMF receives the first UE IP address and the first tunnel identity information from the AN, and sends a context for restoring the first session to the AN, so that the UE and the AN can be restored with the first
  • the wireless connection corresponding to the UE IP address and the first tunnel identification information prevents the AN from discarding the first downlink data.
  • the method further includes: if the first UE is in an idle state, the AMF sends a paging message to the first UE, where the first UE is a UE corresponding to the first UE IP address and the first tunnel identity information.
  • the AMF may select a corresponding method for restoring the first session according to the current specific situation of the first UE. For example, when the first UE is in an idle state, the method may be used to restore the first session, thereby preventing the AN from discarding the first session. Line data; when the first UE is in the connected state, the AMF may directly obtain the session context corresponding to the first session to the SMF corresponding to the first session, and send the session context to the AN, so that the AN restores the AN and the first corresponding to the first session.
  • the air interface connection between the UEs prevents the user experience of dropping the first downlink data by the AN.
  • the method further includes: the AMF sending a third message to the AN, where the third message includes an identifier of the first session, a first correspondence between the first UE IP address and the first tunnel identifier information, and the third The message further includes a second correspondence between the identifier of the second session, the second UE IP address, and the second tunnel identity information.
  • the identifier of the second session may be determined according to the second UE IP address and the second tunnel identifier information included in the second downlink data, and the identifier of the second session is sent to the AMF, so that the AMF does not need to be And determining the identifier of the second session according to the second UE IP address and the second tunnel identifier information, and directly sending the context for restoring the second session to the AN, improving the response speed of the AMF, and reducing the burden of the AMF.
  • the method further includes: the AMF receives the fourth message from the AN, the fourth message includes the identifier of the second session, and the AMF sends a fifth message to the AN, where the fifth message includes a context for establishing the second session.
  • the method further includes: obtaining, by the AMF, the first correspondence between the first UE IP address, the first tunnel identifier information, and the identifier of the first session from the SMF.
  • the first tunnel identifier information is at least one of a tunnel identifier, tunnel information on the AN side, and tunnel information on the UPF side.
  • the present application provides an apparatus for establishing a session, where the apparatus can implement the functions performed by the AN in the method related to the first aspect, and the functions can be implemented by hardware or by executing corresponding software through hardware.
  • the hardware or software includes one or more corresponding units or modules of the above functions.
  • the apparatus includes a processor and a communication interface configured to support the apparatus to perform the corresponding functions of the above methods.
  • the communication interface is used to support communication between the device and other devices.
  • the apparatus can also include a memory for coupling with the processor that retains the program instructions and data necessary for the apparatus to perform the functions described above.
  • the present application provides an apparatus for transmitting data, which may implement the functions performed by the AMF in the method related to the foregoing aspects, and the functions may be implemented by hardware or by executing corresponding software by hardware.
  • the hardware or software includes one or more corresponding units or modules of the above functions.
  • the apparatus includes a processor and a communication interface configured to support the apparatus to perform the corresponding functions of the above methods.
  • the communication interface is used to support communication between the device and other devices.
  • the apparatus can also include a memory for coupling with the processor that retains the program instructions and data necessary for the apparatus to perform the functions described above.
  • the present application provides a computer storage medium for storing computer software instructions for use in the above AN, comprising a program designed to perform the first aspect described above.
  • the present application provides a computer storage medium for storing computer software instructions for use in the above AMF, comprising a program designed to perform the second aspect described above.
  • the present application provides a communication chip in which instructions are stored, which when executed on an AN, cause the communication chip to control the AN to perform the method of the first aspect described above.
  • the present application provides a communication chip in which instructions are stored, which, when run on an AMF, cause the communication chip to control the AMF to perform the method of the second aspect.
  • the present application provides a computer program product, comprising: computer program code, when the computer program code is executed by a communication unit and a processing unit of a communication device, causing the communication device to perform the first aspect The method involved.
  • the application provides a computer program product, comprising: computer program code, when the computer program code is executed by a communication unit and a processing unit of the communication device, causing the communication device to perform the second aspect The method involved.
  • FIG. 1 is a schematic architectural diagram of a communication system to which the present application is applied;
  • FIG. 2 is a schematic flowchart of a method for establishing a session provided by the present application
  • FIG. 3 is a schematic flowchart of another method for establishing a session provided by the present application.
  • FIG. 4 is a schematic flowchart of still another method for establishing a session provided by the present application.
  • FIG. 5 is a schematic flowchart of a method for obtaining a first correspondence relationship provided by the present application.
  • FIG. 6 is an information interaction diagram of establishing a session provided by the present application.
  • FIG. 7 is another information interaction diagram of establishing a session provided by the present application.
  • FIG. 8 is another information interaction diagram of establishing a session provided by the present application.
  • FIG. 9 is another information interaction diagram of establishing a session provided by the present application.
  • FIG. 10 is another information interaction diagram of establishing a session provided by the present application.
  • FIG. 11 is another information interaction diagram of establishing a session provided by the present application.
  • FIG. 12 is a schematic structural diagram of a possible AN provided by the present application.
  • FIG. 13 is a schematic structural diagram of another possible AN provided by the present application.
  • FIG. 14 is a schematic structural diagram of a possible AMF provided by the present application.
  • FIG. 15 is a schematic structural diagram of another possible AMF provided by the present application.
  • FIG. 1 shows a communication system to which the present application is applied.
  • the communication system includes UE 110, UE 120, AN 130, UPF 140, AMF 150, SMF 160, and DN 170.
  • the UE 110 and the UE 120 communicate with the AN 130 through the wireless network, respectively, and the AN 130, the UPF 140, the AMF 150, the SMF 160, and the DN 170 can communicate through the corresponding core network interface (the connection shown in FIG. 1).
  • Each of the above network elements is a physical device.
  • an AN may also be referred to as an AN device
  • an SMF may also be referred to as an SMF device, an SMF network element, or an SMF entity.
  • the AMF may also be referred to as an AMF device, an AMF network element, or an AMF entity.
  • the communication connection between the AN 130 and the UPF 140 can be referred to as a tunnel.
  • a tunnel can carry one or more sessions.
  • a tunnel that carries only one session corresponds to the user plane model of the session granularity.
  • a tunnel carrying multiple sessions corresponds to an aggregated user plane model. The multiple sessions may belong to the same UE or may belong to different UEs.
  • one UE can access the data network through the session granularity tunnel and the aggregated tunnel at the same time.
  • tunnel 1 carries three sessions, which are session 1, session 2, and session 3, respectively, where session 1 and session 2 belong to UE 110 and session 3 belongs to UE 120. Since the tunnel 1 carries multiple sessions, the user plane model between the AN 130 and the UPF 140 is called an aggregated user plane model.
  • a UE may be referred to as a terminal device, an access terminal, a subscriber unit, a subscriber station, a mobile station, a mobile station, a remote station, a remote terminal, a mobile device, a user terminal, a terminal, a wireless communication device, a user agent, or a user.
  • the UE may be a cellular telephone, a handheld device with wireless communication capabilities, a computing device or other processing device connected to a wireless modem, an in-vehicle device, a wearable device, and a user device in a 5th-generation (5G) communication system.
  • 5G 5th-generation
  • the AN may be a base transceiver station (BTS) in a code division multiple access (CDMA) system, or may be a base station in a wideband code division multiple access (WCDMA) system.
  • B, NB may also be an evolved base station (eNB) in a long term evolution (LTE) system, or may be a base station (gNB) in a 5G communication system, the above base station is only an example
  • eNB evolved base station
  • LTE long term evolution
  • gNB base station
  • the AN can also be a relay station, an access point, an in-vehicle device, a wearable device, and other types of devices.
  • the AMF can be responsible for UE attachment, mobility management, tracking area update procedures, and the like.
  • the SMF entity may be responsible for session management of the UE, UPF selection, reselection, IP address allocation, quality of service (QoS), and establishment, modification, and release of sessions.
  • the SMF entity and the AMF entity are connected through the N11 interface.
  • the SMF entity is connected to the UPF through an N4 interface.
  • the AMF entity and the AN are connected through an N2 interface.
  • a message transmitted through the N11 interface may be referred to as an N11 message.
  • a message transmitted over the N4 interface may be referred to as an N4 message.
  • a message transmitted over the N2 interface may be referred to as an N2 message.
  • these messages may have other names in different scenarios, and the present application is not limited thereto.
  • the UPF is connected to the DN for implementing data transmission of the service in the service area of the UPF.
  • the communication system to which the present application is applied is merely an example.
  • the communication system to which the present application is applied is not limited thereto.
  • the number of AN, AMF, SMF, UPF, DN, and UE included in the communication system may be other numbers.
  • the AN, AMF, SMF, DN, and UE may also have other names.
  • the use of AN, AMF, SMF, UPF, DN, and UE is not meant to limit the scope of the application.
  • the AMF is mainly responsible for the mobility management of the UE, such as location update, registration network, handover, and the like.
  • the context information of the UE saved on the AMF 150 mainly includes: a UE identifier, a session identifier, and an SMF identifier.
  • the SMF is mainly responsible for session management of the UE, such as session establishment, modification, and release. Specific functions include assigning an IP address to a user, and selecting an UPF that provides a packet forwarding function.
  • the context information of the session saved on the SMF 160 mainly includes: a session identifier, and a quality of service (QoS) parameter corresponding to the session.
  • the QoS parameters include: allocation and retention priority (ARP), aggregate session maximum bit rate (session-AMBR), and aggregate granularity of UE granularity (per UE). Aggregate maximum bit rate, UE-AMBR).
  • a session may include multiple traffic flows, each of which may have different QoS parameters.
  • the AN is primarily responsible for providing wireless access to the UE.
  • the context saved on the AN 130 mainly includes the wireless connection information between the UE and the AN corresponding to the session (eg, a data radio bearer).
  • DRB identifies the tunnel connection information between the AN and the UP (for example, the UPF side tunnel identifier), the IP address of the UE, and the QoS parameters.
  • An aggregated user plane model can contain multiple sessions.
  • the management method of the user plane model of the session granularity is introduced in conjunction with FIG. 2 .
  • the user plane model When a tunnel carries only one session, the user plane model is called the user plane model of session granularity.
  • the user plane model of session granularity when the session is deactivated (such as when the UE enters the idle state, or the UE is in the connected state but the session of the UE is deactivated), the tunnel between the AN and the UPF is broken.
  • the communication system needs to re-establish (ie, restore) the session corresponding to the downlink data, and the process of restoring the session is as shown in FIG. 2 .
  • the method of restoring a session shown in Figure 2 includes the following steps:
  • the UPF After receiving the downlink data, the UPF sends a data notification to the SMF to notify the SMF that the downlink data needs to be sent.
  • the SMF After receiving the data notification, the SMF sends an N11 message to the AMF, where the N11 message carries the session identifier, the QoS parameter, and the UPF side tunnel information.
  • the UPF side tunnel information is an IP address of the UPF and/or a UPF side tunnel endpoint identifier.
  • the AMF saves the state of the current UE, and the AMF determines whether to execute S204 according to the state of the UE.
  • the AMF sends a paging message to the AN, and the AN triggers the paging process according to the paging message and performs step S204.
  • the AMF does not need to page the UE, and directly executes S205.
  • the UE receives the paging message, and the UE sends a service request to the AMF through the AN.
  • the service request is a response message to the paging message.
  • the AMF sends a context establishment request to the AN, where the context establishment request carries the session identifier, the QoS parameter, and the UPF side tunnel information in S202.
  • the AN triggers a wireless connection establishment process between the UE and the AN according to the received context establishment request.
  • the AN sends a context establishment response of the UE to the AMF, where the context establishment response carries the AN side tunnel information.
  • the AN side tunnel information is an AN IP address and/or an AN side tunnel end point identifier.
  • the AMF sends an N11 message to the SMF, where the N11 message carries the session identifier and the AN side tunnel information.
  • the SMF initiates a user plane path modification process to the UPF. For example, the SMF sends a user plane path modification request carrying the session identifier and the AN side tunnel information to the UPF; the UPF returns a user plane path modification response.
  • the UPF sends the downlink data corresponding to the session to the UE through the user plane tunnel between the AN and the UPF and the DRB between the UE and the AN.
  • the interface between the AMF and the SMF is called an N11 interface, so the message interaction between the two can be simply referred to as an N11 message.
  • the present invention is not limited to a specific message name.
  • the deactivation of a session does not affect the tunnel connection between AN and UP.
  • session 1 is deactivated, but tunnel 1 is not broken.
  • the UPF receives the downlink data corresponding to the session 1, the UPF sends the downlink data directly to the AN through the user plane tunnel between the UPF and the AN.
  • the AN Since the AN has cleared all the information of the session 1 when the session 1 is deactivated, including the DRB information between the AN and the UE, when the AN receives the downlink data, it cannot determine which DRB the downlink data corresponds to, and thus cannot The downlink data is sent to the UE, so that the AN discards the downlink data, which reduces the user experience.
  • the session For a session of the UE, when there is a user plane connection between the UE and the AN, AN and UP, that is, when the data of the UE can be transmitted, the session is in an activation state.
  • the context of the session is saved on the SMF, such as the IP address of the UE, the session identifier, etc.
  • the session is in a deactivation state.
  • the information for that session saved on the AN will be deleted.
  • session 1 Take session 1 as an example. Before the session 1 is deactivated, if the downlink data reaches the AN through the tunnel 1 corresponding to the tunnel connection information 1, and the downlink data carries the QoS parameter 1, according to Table 1, the AN may use the tunnel connection information 1 and QoS in the context information. Parameter 1, determining that the downlink data is the downlink data of the session 1, and transmitting the downlink data to the UE 110 by using the DRB1 corresponding to the wireless connection information 1.
  • Session 2 Wireless connection information 3 Tunnel connection information 1 UE IP2 QoS parameter 1 Session 3 Wireless connection information 4 Tunnel connection information 1 UE IP3 QoS parameter 1
  • the UPF 140 After the session 1 is deactivated, for the above situation, when the downlink data of the session 1 arrives, the UPF 140 sends the downlink data to the AN 130 through the tunnel 1, but since the AN 130 does not have the wireless connection information corresponding to the downlink data, the AN 130 cannot downlink. The data is sent to the UE. Then, the downlink data will be discarded, resulting in a drop in user experience.
  • the AMF saves the UE IP address, the tunnel identification information (such as the tunnel identifier, the tunnel information on the AN side, and the tunnel information on the UPF side) and the UE identifier, the session identifier, and the SMF identifier.
  • the context of the UE stored on the AMF 150 is:
  • UE110 Session 1 SMF160 UE IP1 Tunnel identification information 1
  • UE110 Session 2 SMF160 UE IP2 Tunnel identification information 1
  • UE120 Session 3 SMF160 UE IP3 Tunnel identification information 1
  • FIG. 3 shows a schematic flowchart of a method 300 for establishing a session provided by the present application.
  • the method 300 includes:
  • the AN receives the first downlink data from the UPF, where the first downlink data includes a first UE IP address and first tunnel identifier information.
  • the AN sends a first message to the AMF, where the first message includes the first UE IP address and the first tunnel identity information.
  • the AN receives a second message from the AMF, where the second message includes a context for establishing a first session, where the first session is an IP address with the first UE and the first tunnel identifier.
  • the session corresponding to the information.
  • the AN recovers the wireless connection between the UE and the AN according to the received second message, so that the AN can send the first downlink data to the UE.
  • the first downlink data is any downlink data sent by the UPF, and after receiving the first downlink data, the AN parses the first UE IP address and the first tunnel identifier information.
  • the first tunnel identification information is an identifier of a tunnel (ie, a tunnel identifier) that transmits the first downlink data
  • the first tunnel identifier information is tunnel information of the tunnel on the AN side of the tunnel that transmits the first downlink data.
  • the first tunnel identification information is the tunnel information of the tunnel that transmits the first downlink data on the UPF side
  • the first tunnel identifier information includes at least two of the tunnel identifier, the tunnel information on the AN side, and the tunnel information on the UPF side.
  • the AN side tunnel information includes an AN IP address and/or an AN side tunnel endpoint identifier.
  • the UP side tunnel information includes a UP IP address and/or an UP side tunnel end identifier.
  • the foregoing example is only an example.
  • the first tunnel identifier information is used to identify a tunnel for transmitting the first downlink data.
  • the specific content of the first tunnel identifier information is not limited in this application.
  • the AN After receiving the first downlink data, the AN cannot send the first downlink data to the UE because the wireless connection information corresponding to the first downlink data does not exist on the AN. According to the method described in this application, the AN sends a first message to the AMF, where the first message includes the first UE IP address and the first tunnel identity information, so that the AMF determines the session corresponding to the first UE IP address and the first tunnel identity information.
  • the UE IP address may also be simply referred to as UE IP.
  • the first message may be a notification message, and the notification message is used to notify the AMF that the AN has received the downlink data including the first UE IP address and the first tunnel identity information.
  • the first message may also be a request message, where the request message is used to request to obtain information about a session corresponding to the first UE IP address and the first tunnel identity information.
  • the AMF may send, by using the third message, information about the first session (that is, the first UE IP address and the session corresponding to the first tunnel identification information) to the AN, or may be the first UE (ie, the first The information of part or all of the session of the UE to which a session belongs is sent to the AN.
  • the information of part or all of the session of the UE to which the first session belongs includes: a correspondence between the UE IP address, the tunnel identification information, and the session identifier.
  • the information of the session of the UE includes a first correspondence relationship and a second correspondence relationship, where the first correspondence relationship includes a first correspondence relationship between the first UE IP address, the first tunnel identifier information, and the identifier of the first session;
  • the second correspondence includes a second correspondence between the second UE IP address, the second tunnel identifier information, and the identifier of the second session.
  • the first session and the second session may be all sessions of the UE, or may be only partial sessions of the UE.
  • the first correspondence or the second correspondence may further include: a correspondence between the UE identifier, the SMF identifier, and the foregoing parameter.
  • the SMF identifier is used to identify the SMF.
  • the second message is received from the AMF.
  • the second message is a message carrying a context for establishing a first session.
  • the specific names of the first message and the second message are not limited in this application.
  • the technical solutions of the present application are described below by taking the first message as a notification message and a request message, respectively.
  • the AMF determines information about the first session corresponding to the first UE IP address and the first tunnel identity information according to the first correspondence.
  • the information of the first session may be the identity of the first session.
  • the AMF may save the first correspondence in the form of a table, and determine the information of the first session by querying the table.
  • the AMF may determine the information of the first session by using other methods.
  • the specific form of the first correspondence and the specific manner in which the AMF determines the first session are not limited.
  • the first correspondence may further include a UE to which the first session belongs (ie, the first UE) and an SMF related to the first session.
  • the AMF may determine, according to the first UE IP address and the first tunnel identifier information carried in the first message, and the first correspondence, the UE to which the first session belongs, that is, the first UE, according to the state of the first UE. The recovery process of a session.
  • the AMF initiates a paging procedure to page the first UE.
  • a specific paging procedure reference may be made to the process of paging the UE in the prior art, and details are not described herein.
  • the idle state described above may also be referred to as a connection management idle (CM-IDLE) state.
  • the AMF After the first UE is paged, the AMF sends a session context acquisition request to the first SMF (ie, the SMF managing the first session), the session context acquisition request carrying the identity of the first session. Subsequently, the AMF receives a session context acquisition response from the first SMF, the session context acquisition response carrying the context required to establish the first session, such as the QoS parameters of the first session.
  • the AMF sends a session context setup request to the AN, which context setup request carries the context required to establish the first session.
  • the AN establishes an air interface connection with the first UE according to the context, and sends a session context to the AMF to establish a response.
  • connection management connected CM-CONNECTED
  • the AMF may also send the saved correspondence relationship of the first UE (including but not limited to the first correspondence) to the AN.
  • the AN receives the downlink data (for example, the second downlink data) corresponding to the other session of the first UE
  • the second session corresponding to the second downlink data may be directly determined according to the foregoing correspondence, so that the AN passes the AMF to the second session.
  • the SMF corresponding to the session acquires the context of the second session, and further restores the wireless connection between the UE and the AN corresponding to the second session, so that the AN sends the second downlink data to the UE.
  • the AMF determines, according to the first correspondence, the information corresponding to the first UE IP address and the first tunnel identity information to determine the information of the first session.
  • the information of the first session may be the identity of the first session.
  • the AMF may save the first correspondence in the form of a table, and determine the information of the first session and the first UE by querying the table.
  • the AMF may determine the information of the first session by using other methods.
  • the specific form of the first correspondence and the specific manner in which the AMF determines the first session are not limited.
  • the AMF then sends a third message to the AN, where the third message carries information about some or all of the sessions corresponding to the first UE.
  • the third message may carry the first correspondence and the second correspondence.
  • the first correspondence includes a first correspondence between the first UE IP address, the first tunnel identifier information, and the identifier of the first session;
  • the second correspondence includes the second UE IP address, the second tunnel identifier information, and the first
  • the second correspondence between the three parties identifies the second correspondence.
  • the first correspondence and the second correspondence may be information of all sessions of the first UE (for example, the first UE includes only the first session and the second session), or the first correspondence and the second correspondence are only It is information of a partial session of the first UE (for example, the first UE includes at least 3 sessions).
  • the second session corresponding to the second downlink data may be directly determined according to the foregoing correspondence, so that the AN passes the AMF to the second session.
  • the SMF corresponding to the session acquires the context of the second session, and further restores the wireless connection between the UE and the AN corresponding to the second session, so that the AN sends the second downlink data to the UE.
  • the AMF also stores the correspondence between the UE identifier, the SMF identifier, and the session identifier. Therefore, the third message may carry the correspondence between the UE IP, the tunnel identifier, the session identifier, the UE identifier, and the SMF identifier.
  • the AN determines, according to the correspondence in the third message, whether the first UE has a session in an active state, thereby determining the state of the UE. For an active session, the AN saves the air interface connection information corresponding to the session.
  • the air interface connection information of the session refers to a wireless connection between the UE and the AN. Therefore, when there is no air interface connection information of the session in the session information of the first UE saved by the AN, the AN determines that the UE is in an idle state.
  • the AN determines that the first UE is in a connected state; if the first UE does not have a session in an active state, the AN determines that the UE is in an idle state. Subsequently, the AN performs a process of session recovery according to the state of the first UE. As described below:
  • the AN When the first UE is in the idle state, the AN initiates a paging procedure to page the first UE.
  • a specific paging procedure reference may be made to the process of paging the UE in the prior art, and details are not described herein again.
  • the AN After the first UE is paged, the AN sends a session context acquisition request to the first SMF through the AMF, where the session context acquisition request carries the identifier of the first session; then, the AN receives the session context acquisition response from the first SMF through the AMF, The session context acquisition response carries the context required to establish the first session, such as the QoS parameter of the first session; the AN establishes an air interface connection with the first UE according to the context.
  • the AN does not need to page the UE, and according to the saved first correspondence, the session corresponding to the first downlink data is determined, and the session is sent to the first SMF corresponding to the first session by using the AMF.
  • the context acquisition request is the same as the processing procedure of the AN in the case (3), and details are not described herein again.
  • the AN can send the first downlink data to the first UE.
  • the third message may be a response message of the notification message; when the first message is a request message, the third message may be a response message of the request message.
  • the AMF may also not send a response message of the notification message.
  • the names of the same messages may be referred to in various names.
  • the names of the various messages in the present application are merely examples, and should not be construed as limiting the technical solutions of the present application.
  • the names of the respective messages should be based on their actual functions. .
  • the method 300 for establishing a session provided by the present application, the AN sends the first UE IP address and the first tunnel identification information to the AMF, and receives the context sent by the AMF for restoring the first session, so that the AN can be restored.
  • the first session is corresponding to the first UE IP address and the first tunnel identity information.
  • the method 300 further includes:
  • the AN receives a third message from the AMF, where the third message includes an identifier of the first session, a first correspondence between the first UE IP address and the first tunnel identifier information.
  • the third message further includes a second correspondence between the identifier of the second session, the second UE IP address, and the second tunnel identity information.
  • the second session is any one of the sessions different from the first session in all the sessions corresponding to the first UE.
  • the method 300 further includes:
  • the AN receives second downlink data from the UPF, where the second downlink data includes the second UE IP address and the second tunnel identifier information.
  • the AN determines, according to the saved session information of the first UE, the second UE IP address and the second tunnel identifier information, a session corresponding to the second downlink data (ie, a second session), and sends the first session to the AMF. And a fourth message, where the fourth message includes an identifier of the second session.
  • the AMF sends a context acquisition request to the SMF corresponding to the second session identifier according to the correspondence between the session identifier and the SMF identifier, to obtain the context corresponding to the second session.
  • the AN when the corresponding relationship saved by the AN includes the SMF identifier, the AN sends a session context acquisition request to the SMF corresponding to the second session by using the AMF to obtain a context corresponding to the second session.
  • the AMF receives the session context acquisition response returned by the SMF, and the session context acquisition response carries the context of the second session, such as the QoS parameter corresponding to the second session.
  • the AN receives a fifth message from the AMF, where the fifth message includes a context for establishing the second session.
  • the second downlink data is a session different from the UE corresponding to the first downlink data.
  • the AN determines the first UE according to the second downlink data, including the second UE IP address and the second tunnel identifier information, and according to the second UE.
  • the correspondence received from the AMF determines a session corresponding to the second UE IP address and the second tunnel identity information (ie, the second session), and then performs a recovery process of the second session. Therefore, how to implement session-level session management (ie, session activation) when the communication system adopts the aggregated user plane model, for example, when the deactivated session has new downlink data to be transmitted, the UPF will use the new downlink.
  • the data is directly sent to the AN.
  • the AN After receiving the new downlink data, the AN determines the new downlink corresponding session according to the saved session information of the UE, so that the session context corresponding to the session is obtained by the AMF to the SMF, thereby restoring the session corresponding to the session.
  • the wireless connection between the UE and the AN enables the AN to transmit new downlink data to the UE. That is, the AN can send the new downlink data to the UE according to the method for establishing a session provided by the present application, thereby preventing the AN from discarding the new downlink data due to the inability to send the new downlink data to the UE, thereby improving the user experience. .
  • the fourth message is a message carrying the identifier of the second session
  • the fifth message is a message carrying the context for re-establishing the second session.
  • the name of the fourth message and the fifth message is not limited in this application.
  • FIG. 4 shows another schematic flowchart of a method 400 for establishing a session provided by the present application.
  • the method 400 includes:
  • the AMF receives a first message from the AN, where the first message includes a first UE IP address and first tunnel identity information.
  • the AMF sends a second message to the AN, where the second message includes a context for establishing a first session, where the first session is an IP address with the first UE and the first tunnel identifier.
  • the session corresponding to the information.
  • both AMF and AN can be equivalent to AMF and AN in method 300, and the actions of AMF and AN correspond to the actions of AMF and AN in method 300, in addition
  • the first message and the second message are also the same as the first message and the second message in the method 300. For brevity, details are not described herein again.
  • the AMF receives the first UE IP address and the first tunnel identity information from the AN, and sends a context for establishing the first session to the AN, so that the first UE IP address can be established.
  • the first session corresponding to the first tunnel identification information.
  • the method 400 further includes:
  • the AMF sends a paging message to the AN to page the first UE.
  • the first UE is a UE corresponding to the first UE IP address and the first tunnel identity information.
  • the method 400 further includes:
  • the AMF sends a third message to the AN, where the third message includes an identifier of the first session, a first correspondence between the first UE IP address and the first tunnel identifier information.
  • the third message further includes a second correspondence between the identifier of the second session, the second UE IP address, and the second tunnel identity information.
  • the third message may carry only the first correspondence, and may also carry the first correspondence and the second correspondence.
  • the second session is in a session different from the first session in all sessions corresponding to the first UE. Any one of the sessions.
  • the UPF will be new.
  • the downlink data is directly sent to the AN, and the AN determines the new downlink corresponding session according to the saved session information of the UE after receiving the new downlink data, so that the session context corresponding to the session is obtained by the AMF to the SMF, thereby restoring the session corresponding to the session.
  • the wireless connection between the UE and the AN enables the AN to transmit new downlink data to the UE.
  • the AN can send the new downlink data to the UE according to the method for establishing a session provided by the present application, thereby preventing the AN from discarding the new downlink data due to the inability to send the new downlink data to the UE, thereby improving the user experience. .
  • the method 400 further includes:
  • the AMF receives a fourth message from the AN, where the fourth message includes an identifier of the second session.
  • the AMF sends a fifth message to the AN, where the fifth message includes a context for restoring the second session.
  • the third message, the fourth message, and the fifth message are the same as the third message, the fourth message, and the fifth message in the method 300, and are not described again for brevity.
  • the method 400 further includes:
  • the AMF obtains, by the SMF, the first correspondence between the first UE IP address, the first tunnel identifier information, and the identifier of the first session.
  • FIG. 5 is a schematic flowchart of a method for acquiring a first correspondence relationship by an AMF provided by the present application.
  • the AMF obtains the first correspondence during the session establishment process.
  • the method 500 includes:
  • the UE sends a session setup request to the AMF through the AN to request to establish a session.
  • the session establishment request carries a session identifier (ie, an identifier of the first session) and a data network name (DNN).
  • the AMF selects an SMF that provides a session management service for the UE, and saves a correspondence between the session identifier and the SMF identifier.
  • the AMF sends an N11 message to the SMF.
  • the N11 message may be a session management request (SM request) carrying a session establishment request.
  • SM request session management request
  • the session establishment request carries the session identifier and the DNN.
  • the SMF After receiving the N11 message, the SMF determines whether there is a user plane path between the AN and the UPF. When there is no user plane path between the AN and the UPF, a user plane path establishment process is initiated. For example, the SMF allocates a tunnel identifier, assigns an IP address to the UE, and sends an N4 session setup request to the UPF, where the N4 session setup request carries the session identifier, the DNN, and the tunnel identifier.
  • the N4 session establishment request may further carry the AN side tunnel information.
  • the SMF receives an N4 session establishment response from the UPF, and the N4 session establishment response carries the UP side tunnel information and the tunnel identity.
  • the AN side tunnel information includes an AN IP address and/or an AN side tunnel end identifier.
  • the UP side tunnel information includes a UP IP address and/or an UP side tunnel end identifier.
  • the SMF sends an N11 message to the AMF, where the N11 message carries a first correspondence, that is, a correspondence between the first tunnel identifier information, the first UE IP address, and the identifier of the first session.
  • the first tunnel identifier information is at least one of an UP side tunnel information, an AN side tunnel information, and a tunnel identifier.
  • the N11 message can also carry other information, such as QoS parameters.
  • the AMF saves the first correspondence.
  • the information saved on the AMF includes the correspondence between the UE identifier, the SMF identifier corresponding to the first session, the first tunnel identifier information, the first UE IP address, and the identifier of the first session.
  • the UE identifier is used to uniquely identify a terminal user, and the AMF saves the UE identifier in a process in which the UE registers with the data network.
  • the AMF sends an N2 message to the AN, where the N2 message carries a session identifier, a UE IP, and a QoS parameter, where the N2 message is used to request the AN to establish a radio bearer.
  • the AN initiates a radio bearer establishment process.
  • the AN sends an N2 message to the AMF, where the N2 message is used to indicate that the radio bearer has been established.
  • the embodiment in which the AMF obtains the first correspondence is only an example.
  • the application is not limited thereto.
  • the first correspondence may be configured in the AMF in a pre-configured manner.
  • the AMF may determine, according to the first correspondence, the first session corresponding to the first UE IP address and the first tunnel identifier information. And then re-establish the first session.
  • the first tunnel identifier information is at least one of an identifier of a tunnel (ie, a tunnel identifier) that transmits the first downlink data, tunnel information on the AN side, and tunnel information on the UPF side.
  • a tunnel identifier identifier of a tunnel
  • the foregoing example is only an example.
  • the first tunnel identifier information is used to identify a tunnel for transmitting the first downlink data.
  • the specific content of the first tunnel identifier information is not limited in this application.
  • the AMF updates the saved information and adds the session information related to the second session.
  • the information saved on the AMF is updated to include:
  • the AMF saves the correspondence, and when paging the UE, the paging process is triggered by the AMF.
  • the method includes:
  • the AN receives downlink data from the UPF, where the downlink data includes a UE IP address and tunnel identity information (ie, session information).
  • tunnel identity information ie, session information
  • the AN Because the AN does not save the wireless connection information corresponding to the downlink data, the AN sends a notification message to the AMF, where the notification message carries the session information in S601.
  • the AMF determines, according to the saved correspondence (that is, the UE identifier-session information-session identifier-SMF identifier), the session, the UE, and the SMF corresponding to the received session information.
  • the AMF performs the different steps described below according to different states of the UE corresponding to the session information.
  • the AMF When the UE is in the idle state (the AMF can determine the state of the UE according to the saved UE context, which is the prior art and will not be described again), the AMF triggers the paging procedure, and executes S604 to S606.
  • the AMF sends a paging message to the AN, where the paging message carries a paging identifier, where the paging identifier is used to identify the UE.
  • the AMF may send all or part of the correspondence related to the UE to the AN, so that when the AN receives the downlink data of other sessions of the UE from the UPF again, the AMF may directly directly associate with the corresponding relationship stored in the AN.
  • the session corresponding to the downlink data is determined, so that the session context corresponding to the session is obtained, no need to send a notification message to the AMF, and the AMF does not need to determine the session corresponding to the downlink data, thereby reducing the burden of the AMF.
  • the AMF may send all or part of the correspondence related to the UE to the AN through a paging message, or may send all or part of the correspondence related to the UE to the AN by using a message other than the paging message.
  • the AN pages the UE according to the received paging message.
  • the UE that is paged initiates a service request procedure to resume the session.
  • the service request process may include S607 to S611.
  • the AMF When the UE is in the connected state (the AMF can determine the state of the UE according to the saved UE context, which is a prior art and will not be described again), the AMF triggers a context establishment procedure, for example, S607 is performed.
  • the AMF sends a session context acquisition request to the SMF corresponding to the session information, where the session context acquisition request carries the session identifier.
  • the SMF sends a session context acquisition response to the AMF, where the session context acquisition response carries a session context corresponding to the session identifier, and the session context may be, for example, QoS information of the session.
  • the AMF forwards a session context setup request to the AN, where the session context setup request carries the session context in S608.
  • the AN triggers a wireless connection establishment process between the UE and the AN.
  • the SMF sends the determined session context to the AN through the forwarding of the AMF
  • the AN establishes a DRB between the AN and the UE according to the received session context. Therefore, AMF does not need to understand the session context sent by the SMF.
  • the AN sends a session context establishment response to the AMF.
  • FIG. 7 shows another information interaction diagram of establishing a session provided by the present application.
  • the AMF passes the correspondence to the AN, and the correspondence is held by the AN.
  • the paging procedure is triggered by the AN.
  • the method includes:
  • the AN receives downlink data from the UPF, and obtains a UE IP address and tunnel identity information (that is, session information) from the downlink data.
  • a UE IP address and tunnel identity information that is, session information
  • the AN sends a request message to the AMF, where the request message carries the session information in S701.
  • the request message is used to request the AMF to send the correspondence relationship of the UE corresponding to the session information to the AN.
  • the AMF determines the session, the UE, and the SMF corresponding to the received session information according to the saved correspondence (ie, the UE identifier-session information-session identifier-SMF identifier), and sends a response message to the AN, where the response message carries the corresponding
  • the relationship is such that the AN saves the correspondence and establishes a session corresponding to the downlink data in S701 according to the correspondence.
  • the response message in S703 may carry other correspondences related to the UE in S703 (for example, all or part of the correspondence between the UEs), so that when the AN receives the downlinks of other sessions belonging to the UE from the UPF again.
  • the session corresponding to the downlink data may be directly determined according to the correspondence stored in the AN, so that the session context corresponding to the session is obtained.
  • the AN performs the different steps described below according to different states of the UE corresponding to the session information. It is to be noted that the AN determines the state of the UE according to the context information of the UE stored in the AN. In an implementation manner, when the context information of the UE stored in the AN has wireless connection information, the AN determines that the UE is connected. Otherwise, the AN determines that the UE is in an idle state.
  • the AN When the UE is in the idle state (the AN can determine the state of the UE according to the context information of the UE saved in the AN), the AN triggers the paging procedure, and S704 is performed.
  • the AN pages the UE.
  • the UE that is paged initiates a service request procedure to resume the session.
  • the service request process may include S706 to S708.
  • the AN When the UE is in the connected state (the AN can determine the state of the UE according to the context information of the UE saved in the AN), the AN triggers the context establishment procedure, and performs S706.
  • the AN sends a session context acquisition request to the SMF corresponding to the session information by using the AMF, where the session context acquisition request carries the session identifier.
  • the SMF sends a session context acquisition response to the AN through the AMF, where the session context acquisition response carries a context for establishing a session, and the context may be, for example, QoS information of the session.
  • the AN triggers a radio bearer setup procedure between the UE and the AN.
  • the AN sends a session context setup response to the SMF.
  • FIG. 8 shows another information interaction diagram of establishing a session provided by the present application.
  • the AMF passes the correspondence to the AN, and the correspondence is held by the AN.
  • the paging process is triggered by the AMF.
  • the method includes:
  • the AN receives downlink data from the UPF, and obtains a UE IP address and tunnel identity information (that is, session information) from the downlink data. If the AN stores the wireless connection information of the UE corresponding to the session information, the AN determines that the UE is in the connected state. At this time, the AN can directly request the session context from the SMF through the AMF, so as to restore the session corresponding to the received downlink data. .
  • a UE IP address and tunnel identity information that is, session information
  • the AN determines that the UE is in an idle state. At this time, because the AN cannot determine which session the session information belongs to, the wireless corresponding to the downlink data cannot be determined. The connection information, therefore, the AN sends a request message to the AMF, the request message carrying the session information in S801. The request message is used to notify the AMF that downlink data is sent to the AN, and is used to request the AMF to send all or part of the correspondence of the UE corresponding to the session information to the AN.
  • S801 to S802 may be replaced by the following steps: S801', the SMF receives an activation session request sent by the UPF, and carries the session identifier.
  • the activation session request is used to trigger a connection corresponding to the SMF recovery session.
  • S802' the SMF sends an N11 message to the AMF, carrying the session information.
  • the session information includes QoS parameters corresponding to the session, tunnel information of the UPF, and the like.
  • the AMF determines that the UE is in an idle state, the AMF pages the UE and transmits all or part of the correspondence relationship of the UE to the AN.
  • the AMF determines that the UE is in the connected state, the AMF sends the session information to the AN, and triggers the AN to restore the DRB connection between the AN and the UE according to the session information. That is, the AMF sends all or part of the correspondence relationship of the UE to the AN, which may be triggered by the request message sent by the AN in the aggregated user plane model scenario, or may be the user plane model by the session granularity. Triggered by the N11 message sent by the SMF.
  • the AMF determines the session, the UE, and the SMF corresponding to the received session information according to the session information received from the AN and the saved correspondence (ie, the UE identifier-session information-session identifier-SMF identifier). In addition, the AMF sends the correspondence of the UE to the AN through a paging message or a message other than the paging message.
  • the AMF may trigger a paging process after determining the UE corresponding to the session information, that is, the AMF sends a paging message to the AN.
  • the AN sends a paging message to the UE.
  • the UE After the UE is paged, the UE initiates a service request procedure. For example, the UE sends a service request message to the AMF, and the AMF receives the service request message, and sends a session context acquisition request to the SMF corresponding to the session information described in S801, where the session context acquisition request carries the session identifier.
  • the AN When the AN receives the downlink data of the other session of the UE again, the AN triggers the context establishment process according to the saved relationship of the UE, and executes S807.
  • the AN determines the session identifier corresponding to the downlink data according to the stored relationship between the UE and the UE IP address and the tunnel identifier information in the downlink data, and the AN sends a session context acquisition request to the SMF corresponding to the session identifier by using the AMF, and carries the request Session ID.
  • the SMF sends a session context acquisition response to the AN through the AMF, and carries the session context corresponding to the session identifier.
  • the session context may be QoS information of the session, tunnel information of the UPF, and the like.
  • the AN since the session context determined by the SMF is used for sending to the AN, the AN establishes a DRB between the AN and the UE. Therefore, the AMF does not need to understand the session context sent by the SMF, that is, the AMF forwards the session context to the AN.
  • the AN triggers a wireless connection establishment process between the UE and the AN according to the received session context.
  • Figures 9 through 11 show the operation of AN and AMF under abnormal conditions.
  • FIG. 9 shows another information interaction diagram of establishing a session provided by the present application.
  • the method shown in FIG. 9 describes a scenario in which the downlink data is received again before the AN receives the correspondence between the UEs, and the method includes:
  • S901 The AN receives the downlink data of the session 1 from the UPF, and obtains the UE IP address and the tunnel identity information (that is, the session information). It should be understood that "Session 1" is only used to identify the session to which the downlink data belongs, in order to distinguish it from the downlink data in S903, at which time the AN does not know which session the downlink data belongs to.
  • the AN since the AN does not store the wireless connection information corresponding to the downlink data, the AN sends a notification message or a request message to the AMF according to the method shown in FIG. 6 to FIG. 8.
  • the notification message carries the session information in S901, and is used to notify the AMF that the AN has received the downlink data corresponding to the session information.
  • the request message carries session information in the downlink data from the session 1, and is used to request the AMF to send the correspondence of the session information to the AN.
  • the AN receives the downlink data of the session 2 from the UPF.
  • the AN buffers the downlink data of the session 2, and does not send a notification message or a request message.
  • the AMF sends a response message to the notification message or the request message in the S902
  • the downlink data of the session 1 and the session 2 are processed according to the correspondence carried in the response message.
  • the specific processing procedure is: the AN determines the session identifier corresponding to the downlink data according to the correspondence relationship, that is, session 1 and session 2; and the AN determines the UE.
  • the status determines that the paging UE or the SMF corresponding to the session identifier by the AMF directly requests the session context corresponding to the session 1 and the session context corresponding to the session 2.
  • the AN When the AN chooses to execute S905, that is, the AN sends a notification message or a request message to the AMF, and the notification message or the request message carries the session information parsed from the downlink data of the session 2, and at this time, the AMF may execute S906.
  • the operation of the AMF is as follows: the AMF does not process; or, when the AMF determines that the corresponding relationship of the UE has been sent to the AN, the AMF sends a response message to the AN to indicate to the AN that the AMF has been delivered and described in S905. Correspondence of matching session information.
  • FIG. 10 shows another information interaction diagram of establishing a session provided by the present application.
  • FIG. 10 and FIG. 11 are applicable to a scenario in which the UE accesses the DN through the aggregated user plane model and the session granularity user plane model at the same time.
  • the UE accesses DN1 through an aggregate tunnel and accesses DN2 through a session tunnel.
  • the UE has 2 sessions on the aggregation tunnel. There is 1 session on the session tunnel.
  • the process of FIG. 10 is performed. As shown in FIG. 10, the method includes:
  • the UPF receives downlink data.
  • the UPF sends a downlink data notification message to the SMF, where the downlink data notification message carries a session identifier, to notify the SMF to trigger connection recovery of the session identifier corresponding session.
  • the SMF sends an N11 message to the AMF, and carries a session context, where the session context includes a QoS parameter corresponding to the session identifier, UPF tunnel information, and the like.
  • the AMF sends the correspondence of the UE to the AN through a message other than the paging message, that is, the correspondence between the session 1, the UE identity, the SMF identifier, and the session information of the session 1.
  • the AN sends a notification message or a request message to the AMF, where the notification message or the request message carries the UE IP address and tunnel identification information (ie, session information) obtained from the downlink data of the session 1.
  • tunnel identification information ie, session information
  • the AMF After receiving the notification message or the request message, the AMF determines that the AMF has sent the corresponding relationship to the UE according to the corresponding relationship saved by the AMF, or has already paged the UE, and the AMF operation may be as follows: the received notification message or the request message is not received. Any processing is performed; or, the AMF sends a response message to the AN to indicate that the AMF has sent the corresponding correspondence to the AN or the AMF has paged the UE.
  • FIG. 11 shows another information interaction diagram of establishing a session provided by the present application.
  • the process of FIG. 11 is performed. As shown in FIG. 11, the method includes:
  • the AN receives the downlink data of the session 1 from the UPF, and obtains the UE IP address and the tunnel identification information (that is, the session information). At this time, the AN does not know which session the session information belongs to, and the "session 1" may be any one session.
  • the AN Because the AN does not know which session the session information belongs to, according to the method 300, the AN sends a notification message or an acquisition request to the AMF, where the request message carries the session information.
  • the AMF After receiving the notification message or the request message, the AMF determines the UE corresponding to the session information according to the session information and the correspondence relationship saved by the AMF. And, the AMF sends the correspondence of the UE to the AN, and/or the AMF sends a paging message to the AN.
  • the AMF receives an N11 message from the SMF, as shown in S1104a-S1104c.
  • the UPF receives the downlink data.
  • the UPF sends a downlink data notification to the SMF, and carries the session identifier.
  • the SMF sends an N11 message to the AMF, and carries the session context corresponding to the session identifier, including QoS parameters, UPF tunnel information, and the like.
  • the AMF may perform step S1105 or perform steps S1106 and S1107.
  • the AMF sends a paging message to the AN.
  • the operation after the AN receives the paging message described in S1106 may be:
  • S1107 does not perform any processing on the paging message; or, the AN sends a response message to the AMF to indicate that the AN has paged the UE.
  • AN and AMF include corresponding hardware structures and/or software modules for performing various functions in order to implement the above functions.
  • Those skilled in the art will readily appreciate that the present application can be implemented in a combination of hardware or hardware and computer software in combination with the elements and algorithm steps of the various examples described in the embodiments disclosed herein. Whether a function is implemented in hardware or computer software to drive hardware depends on the specific application and design constraints of the solution. A person skilled in the art can use different methods to implement the described functions for each particular application, but such implementation should not be considered to be beyond the scope of the present application.
  • the present application may divide the functional units of AN and the like according to the above method examples.
  • each functional unit may be divided corresponding to each function, or two or more functions may be integrated into one processing unit.
  • the above integrated unit can be implemented in the form of hardware or in the form of a software functional unit. It should be noted that the division of the unit in the present application is schematic, and is only a logical function division, and the actual implementation may have another division manner.
  • FIG. 12 shows a possible structural diagram of the AN involved in the above embodiment.
  • the AN 1200 includes a processing unit 1202 and a communication unit 1203.
  • Processing unit 1202 is for controlling management of the actions of AN 1200, for example, processing unit 1202 is configured to support AN 1200 to perform S320 of FIG. 3 and/or other processes for the techniques described herein.
  • Communication unit 1203 is used to support communication between AN 1200 and other network entities, such as with AMF.
  • the AN 1200 may further include a storage unit 1201 for storing program codes and data of the AN1200.
  • the processing unit 1202 may be a processor or a controller, for example, may be a central processing unit (CPU), a general-purpose processor, a digital signal processor (DSP), and an application-specific integrated circuit (application-specific). Integrated circuit (ASIC), field programmable gate array (FPGA) or other programmable logic device, transistor logic device, hardware component, or any combination thereof. It is possible to implement or carry out the various illustrative logical blocks, modules and circuits described in connection with the present disclosure.
  • the processor may also be a combination of computing functions, for example, including one or more microprocessor combinations, a combination of a DSP and a microprocessor, and the like.
  • the communication unit 1203 may be a communication interface.
  • the storage unit 1201 may be a memory.
  • the communication unit 1203 is configured to: receive the first downlink data from the UPF, where the first downlink data includes the first UE IP address and the first tunnel identity information; and send the first message to the AMF, where the first message includes a first UE IP address and first tunnel identification information; receiving, by the AMF, a second message, where the second message includes a context for establishing a first session, where the first session is an IP address with the first UE and the first tunnel identity information The corresponding session.
  • the AN1200 can restore the first UE IP address and the first tunnel identifier between the UE and the AN by sending the first UE IP address and the first tunnel identifier information to the AMF, and receiving the context sent by the AMF to recover the first session.
  • the wireless connection corresponding to the information prevents the AN1200 from discarding the first downlink data.
  • the communication unit 1203 is further configured to: receive, by the AMF, a third message, where the third message includes an identifier of the first session, a first correspondence between the first UE IP address and the first tunnel identifier information, where the first The three messages further include a second correspondence between the identifier of the second session, the second UE IP address, and the second tunnel identity information.
  • the session corresponding to the downlink data is determined according to the second correspondence, so that the session context corresponding to the second session is obtained from the SMF through the AMF, thereby The wireless connection corresponding to the second UE IP address and the second tunnel identification information between the UE and the AN1200 can be restored, and the AN1200 is prevented from discarding the second downlink data.
  • the communication unit 1203 is further configured to: receive second downlink data from the UPF, where the second downlink data includes the second UE IP address and the second tunnel identifier information; and send an identifier of the second session to the AMF. Receiving a context for establishing a second session from the AMF.
  • the identifier of the second session may be determined according to the second UE IP address and the second tunnel identifier information included in the second downlink data, and the identifier of the second session is sent to the AMF, so that the AMF does not need to be used. And determining the identifier of the second session according to the second UE IP address and the second tunnel identifier information, and directly sending the context for restoring the second session to the AN1200, improving the response speed of the AMF, and reducing the burden of the AMF.
  • the communication unit 1203 is further configured to: if the first UE is in an idle state, send a paging message to the first UE, where the first UE is a UE corresponding to the first UE IP address and the first tunnel identity information.
  • the AN1200 may select a corresponding method for restoring the first session according to the current situation of the first UE. For example, when the first UE is in the idle state, the method may be used to restore the first session, so that the AN1200 can be prevented from discarding the first session. When the first UE is in the connected state, the AN1200 can directly obtain the session context corresponding to the first session by using the AMF to the SMF corresponding to the first session, thereby restoring the air interface connection between the AN1200 and the first UE corresponding to the first session. To avoid the user experience degradation caused by the AN discarding the first downlink data.
  • the first tunnel identifier information is at least one of a tunnel identifier, tunnel information on the AN side, and tunnel information on the UPF side.
  • the communication unit 1203 is further configured to: send the first downlink data to the first UE by using the first session, where the first UE is a UE corresponding to the first UE IP address and the first tunnel identity information.
  • the processing unit 1202 is a processor
  • the communication unit 1203 is a communication interface
  • the storage unit 1201 is a memory
  • the AN involved in the present application may be the AN shown in FIG.
  • the AN 1300 includes a processor 1302, a communication interface 1303, and a memory 1301.
  • the communication interface 1303, the processor 1302, and the memory 1301 can communicate with each other through an internal connection path to transfer control and/or data signals.
  • FIG. 14 shows a possible structural diagram of the AMF involved in the above embodiment.
  • the AMF 1400 includes a processing unit 1402 and a communication unit 1403.
  • Processing unit 1402 is for controlling management of the actions of AMF 1400, for example, processing unit 1402 is configured to support AMF 1400 to perform S410 of FIG. 4 and/or other processes for the techniques described herein.
  • Communication unit 1403 is used to support communication between AMF 1400 and other network entities, such as with AN.
  • the AMF 1400 may also include a storage unit 1401 for storing program codes and data of the AMF 1400.
  • the processing unit 1402 may be a processor or a controller, such as a CPU, a general purpose processor, a DSP, an ASIC, an FPGA or other programmable logic device, a transistor logic device, a hardware component, or any combination thereof. It is possible to implement or carry out the various illustrative logical blocks, modules and circuits described in connection with the present disclosure.
  • the processor may also be a combination of computing functions, for example, including one or more microprocessor combinations, a combination of a DSP and a microprocessor, and the like.
  • the communication unit 1403 may be a communication interface or the like.
  • the storage unit 1401 may be a memory.
  • the communication unit 1403 is configured to: receive a first message from the AN, where the first message includes a first UE IP address and first tunnel identification information; and send a second message to the AN, where the second message includes The context of a session, the first session being a session corresponding to the first UE IP address and the first tunnel identity information.
  • the AMF 1400 receives the first UE IP address and the first tunnel identity information from the AN, and sends a context for restoring the first session to the AN, so that the UE and the AN can be restored to correspond to the first UE IP address and the first tunnel identity information.
  • the wireless connection prevents the AN from discarding the first downlink data.
  • the communication unit 1403 is further configured to: if the first UE is in an idle state, send a paging message to the first UE, where the first UE is a UE corresponding to the first UE IP address and the first tunnel identity information.
  • the AMF 1400 may select a corresponding method for restoring the first session according to the current specific situation of the first UE. For example, when the first UE is in an idle state, the method may be used to restore the first session, thereby preventing the AN from discarding the first session.
  • the data is sent to the AMF, and the AMF 1400 can directly obtain the session context corresponding to the first session and send it to the AN, so that the AN restores the AN and the first corresponding to the first session.
  • the air interface connection between the UEs prevents the user experience of dropping the first downlink data by the AN.
  • the communication unit 1403 is further configured to: send a third message to the AN, where the third message includes an identifier of the first session, a first correspondence between the first UE IP address and the first tunnel identifier information, and a third The message further includes a second correspondence between the identifier of the second session, the second UE IP address, and the second tunnel identity information.
  • the identifier of the second session may be determined according to the second UE IP address and the second tunnel identifier information included in the second downlink data, and the identifier of the second session is sent to the AMF 1400, so that the AMF 1400 does not need to be used. And determining the identifier of the second session according to the second UE IP address and the second tunnel identifier information, and directly sending the context for restoring the second session to the AN, improving the response speed of the AMF 1400 and reducing the burden of the AMF 1400.
  • the communication unit 1403 is further configured to: receive an identifier of the second session from the AN; and send a context for establishing the second session to the AN.
  • the communication unit 1403 is further configured to: acquire, from the SMF, a first correspondence between the first UE IP address, the first tunnel identifier information, and the identifier of the first session.
  • the first tunnel identifier information is at least one of a tunnel identifier, tunnel information on the AN side, and tunnel information on the UPF side.
  • the AMF involved in the present application may be the AMF shown in FIG.
  • the AMF 1500 includes a processor 1502, a communication interface 1503, and a memory 1501.
  • the communication interface 1503, the processor 1502, and the memory 1501 can communicate with each other through an internal connection path to transfer control and/or data signals.
  • the AN or AMF in the apparatus and method embodiments correspond exactly, and the corresponding steps are performed by the corresponding modules, for example, the communication unit performs the steps of transmitting and/or receiving in the method embodiment, and the steps other than sending and/or receiving may be performed by The processing module or processor executes.
  • the processing module or processor executes.
  • the specific module reference may be made to the corresponding method embodiment, which is not described in detail.
  • the present application also provides a communication chip in which instructions are stored, which when executed on the AN 1200 or AN 1300, cause the communication chip to perform the method corresponding to the AN in the various implementations described above.
  • the present application also provides a communication chip in which instructions are stored which, when run on the AMF 1400 or AMF 1500, cause the communication chip to perform the AMF corresponding method of the various implementations described above.
  • the size of the sequence number of each process does not mean the order of execution sequence, and the order of execution of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the present application.
  • the steps of a method or algorithm described in connection with the present disclosure may be implemented in a hardware or may be implemented by a processor executing software instructions.
  • the software instructions may be composed of corresponding software modules, which may be stored in a random access memory (RAM), a flash memory, a read only memory (ROM), an erasable programmable read only memory ( Erasable programmable ROM (EPROM), electrically erasable programmable read only memory (EEPROM), registers, hard disk, removable hard disk, compact disk read only (CD-ROM) or any other form of storage medium known in the art.
  • An exemplary storage medium is coupled to the processor to enable the processor to read information from, and write information to, the storage medium.
  • the storage medium can also be an integral part of the processor.
  • the processor and the storage medium can be located in an ASIC. Additionally, the ASIC can be located in an AN or AMF. Of course, the processor and the storage medium can also exist as discrete components in the AN and AMF.
  • the computer program product includes one or more computer instructions.
  • the computer can be a general purpose computer, a special purpose computer, a computer network, or other programmable device.
  • the computer instructions can be stored in or transmitted by a computer readable storage medium.
  • the computer instructions may be from a website site, computer, server or data center via a wired (eg, coaxial cable, fiber optic, digital subscriber line (DSL)) or wireless (eg, infrared, wireless, microwave, etc.) Another website site, computer, server, or data center for transmission.
  • the computer readable storage medium can be any available media that can be accessed by a computer or a data storage device such as a server, data center, or the like that includes one or more available media.
  • the usable medium may be a magnetic medium (eg, a floppy disk, a hard disk, a magnetic tape), an optical medium (eg, a digital versatile disc (DVD), or a semiconductor medium (eg, a solid state disk (SSD)). Wait.

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Abstract

本申请公开了一种建立会话的方法和装置，该方法包括：接入网AN从用户面功能UPF接收第一下行数据，该第一下行数据包括第一用户设备UE网络协议IP地址和第一隧道标识信息；该AN向接入和移动性管理功能AMF发送第一消息，该第一消息包括该第一UE IP地址和该第一隧道标识信息；该AN从该AMF接收第二消息，该第二消息包括用于建立第一会话的上下文，该第一会话为与该第一UE IP地址和该第一隧道标识信息对应的会话。根据本申请提供的建立会话的方法，可以建立与第一UE IP地址和第一隧道标识信息对应的第一会话。

Description

建立会话的方法和装置
本申请要求于2017年7月3日提交中国专利局、申请号为201710533748.1、申请名称为“建立会话的方法和装置”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
本申请涉及通信领域，尤其涉及无线通信领域中建立会话的方法和装置。
背景技术
用户面模型指的是接入网(access network，AN)与用户面功能(user plane function，UPF)之间的隧道模型，其中，隧道是指AN与UPF之间的通信路径。
聚合型用户面模型是用户面模型中的一种。对于聚合型用户面模型，一个隧道对应多个会话，该多个会话可以属于一个终端设备，也可以属于多个终端设备。其中，会话用于为用户设备(user equipment，UE)和数据网络(data network，DN)提供协议数据单元(protocol data unit，PDU)连接服务。当隧道对应的若干个会话被去激活时，AN接收到新的下行数据后无法向UE发送该新的下行数据，从而导致AN丢弃该新的下行数据，降低用户体验。
发明内容
有鉴于此，本申请提供了一种建立会话的方法和装置，可以解决上述聚合型用户面模型中AN丢弃下行数据的问题。
第一方面，提供了一种建立会话的方法，包括：AN从UPF接收第一下行数据，第一下行数据包括第一UE网络协议(internet protocol，IP)地址和第一隧道标识信息；AN向接入和移动性管理功能(access and mobility management function，AMF)发送第一消息，该第一消息包括第一UE IP地址和第一隧道标识信息；AN从AMF接收第二消息，该第二消息包括用于建立第一会话的上下文，第一会话为与第一UE IP地址和第一隧道标识信息对应的会话。
根据本申请提供的建立会话的方法，AN通过向AMF发送第一UE IP地址和第一隧道标识信息，并接收AMF发送的用于恢复第一会话的上下文，从而可以恢复UE与AN之间与第一UE IP地址和第一隧道标识信息对应的无线连接，避免AN丢弃第一下行数据。
可选地，所述方法还包括：AN从AMF接收第三消息，该第三消息包括第一会话的标识、第一UE IP地址和第一隧道标识信息之间的第一对应关系，第三消息还包括第二会话的标识、第二UE IP地址和第二隧道标识信息之间的第二对应关系。
当AN接收到第二会话对应的下行数据时，就可以根据所述第二对应关系确定下行数据对应的会话，即第二会话，从而通过AMF从会话管理功能(session management function， SMF)获取到第二会话对应的会话上下文，从而可以恢复UE与AN之间与第二UE IP地址和第二隧道标识信息对应的无线连接，避免AN丢弃第二下行数据。
可选地，所述方法还包括：AN从UPF接收第二下行数据，第二下行数据包括第二UE IP地址和第二隧道标识信息；AN向AMF发送第四消息，该第四消息包括第二会话的标识；AN从AMF接收第五消息，该第五消息包括用于建立第二会话的上下文。
当AN接收到第二下行数据时，可以根据第二下行数据包括的第二UE IP地址和第二隧道标识信息确定第二会话的标识，并向AMF发送第二会话的标识，从而，AMF无需再根据第二UE IP地址和第二隧道标识信息确定第二会话的标识，可以直接将用于恢复第二会话的上下文发送给AN，提高了AMF的响应速度，减小了AMF的负担。
可选地，所述方法还包括：若第一UE处于空闲态，则AN向第一UE发送寻呼消息，该第一UE为与第一UE IP地址和第一隧道标识信息对应的UE。
AN可以根据第一UE当前的具体情况选择相应的恢复第一会话的方法，例如当第一UE处于空闲态时，可以采取上述寻呼的方法恢复第一会话，从而可以避免AN丢弃第一下行数据；当第一UE处于连接态时，AN可以直接通过AMF向第一会话对应的SMF获取第一会话对应的会话上下文，从而恢复第一会话对应的AN与第一UE之间的空口连接，避免AN丢弃第一下行数据带来的用户体验降低。
可选地，第一隧道标识信息为隧道标识、AN侧的隧道信息和UPF侧的隧道信息中的至少一种。
可选地，所述方法还包括：AN通过第一会话向第一UE发送第一下行数据，第一UE为与第一UE IP地址和第一隧道标识信息对应的UE。
第二方面，提供了一种建立会话的方法，包括：AMF从AN接收第一消息，该第一消息包括第一UE IP地址和第一隧道标识信息；AMF向AN发送第二消息，该第二消息包括用于建立第一会话的上下文，该第一会话为与第一UE IP地址和第一隧道标识信息对应的会话。
根据本申请提供的建立会话的方法，AMF从AN接收第一UE IP地址和第一隧道标识信息，并向AN发送用于恢复第一会话的上下文，从而可以恢复UE与AN之间与第一UE IP地址和第一隧道标识信息对应的无线连接，避免AN丢弃第一下行数据。
可选地，所述方法还包括：若第一UE处于空闲态，则AMF向第一UE发送寻呼消息，该第一UE为与第一UE IP地址和第一隧道标识信息对应的UE。
AMF可以根据第一UE当前的具体情况选择相应的恢复第一会话的方法，例如当第一UE处于空闲态时，可以采取上述寻呼的方法恢复第一会话，从而可以避免AN丢弃第一下行数据；当第一UE处于连接态时，AMF可以直接向第一会话对应的SMF获取第一会话对应的会话上下文发，并送给AN，从而使得AN恢复第一会话对应的AN与第一UE之间的空口连接，避免AN丢弃第一下行数据带来的用户体验降低。
可选地，所述方法还包括：AMF向AN发送第三消息，第三消息包括第一会话的标识、第一UE IP地址和第一隧道标识信息之间的第一对应关系，该第三消息还包括第二会话的标识、第二UE IP地址和第二隧道标识信息之间的第二对应关系。
当AN接收到第二下行数据时，可以根据第二下行数据包括的第二UE IP地址和第二隧道标识信息确定第二会话的标识，并向AMF发送第二会话的标识，从而，AMF无需再 根据第二UE IP地址和第二隧道标识信息确定第二会话的标识，可以直接将用于恢复第二会话的上下文发送给AN，提高了AMF的响应速度，减小了AMF的负担。
可选地，所述方法还包括：AMF从AN接收第四消息，第四消息包括第二会话的标识；AMF向AN发送第五消息，该第五消息包括用于建立第二会话的上下文。
可选地，所述方法还包括：AMF从SMF获取第一UE IP地址、第一隧道标识信息与第一会话的标识之间的第一对应关系。
可选地，所述第一隧道标识信息为隧道标识、AN侧的隧道信息和UPF侧的隧道信息中的至少一种。
第三方面，本申请提供了一种建立会话的装置，该装置可以实现上述第一方面所涉及的方法中AN所执行的功能，所述功能可以通过硬件实现，也可以通过硬件执行相应的软件实现。所述硬件或软件包括一个或多个上述功能相应的单元或模块。
在一种可能的设计中，该装置的结构中包括处理器和通信接口，该处理器被配置为支持该装置执行上述方法中相应的功能。该通信接口用于支持该装置与其它装置之间的通信。该装置还可以包括存储器，该存储器用于与处理器耦合，其保存该装置必要的程序指令和数据用于实现上述功能。
第四方面，本申请提供了一种传输数据的装置，该装置可以实现上述方面所涉及的方法中AMF所执行的功能，所述功能可以通过硬件实现，也可以通过硬件执行相应的软件实现。所述硬件或软件包括一个或多个上述功能相应的单元或模块。
在一种可能的设计中，该装置的结构中包括处理器和通信接口，该处理器被配置为支持该装置执行上述方法中相应的功能。该通信接口用于支持该装置与其它装置之间的通信。该装置还可以包括存储器，该存储器用于与处理器耦合，其保存该装置必要的程序指令和数据用于实现上述功能。
第五方面，本申请提供了一种计算机存储介质，用于储存为上述AN所用的计算机软件指令，其包含用于执行上述第一方面所设计的程序。
第六方面，本申请提供了一种计算机存储介质，用于储存为上述AMF所用的计算机软件指令，其包含用于执行上述第二方面所设计的程序。
第七方面，本申请提供了一种通信芯片，其中存储有指令，当其在AN上运行时，使得所述通信芯片控制AN执行上述第一方面的方法。
第八方面，本申请提供了一种通信芯片，其中存储有指令，当其在AMF上运行时，使得所述通信芯片控制AMF执行上第二方面的方法。
第九方面，本申请提供了一种计算机程序产品，所述计算机程序产品包括：计算机程序代码，当所述计算机程序代码被通信装置的通信单元和处理单元运行时，使得通信装置执行第一方面所涉及的方法。
第十方面，本申请提供了一种计算机程序产品，所述计算机程序产品包括：计算机程序代码，当所述计算机程序代码被通信装置的通信单元和处理单元运行时，使得通信装置执行第二方面所涉及的方法。
附图说明
图1是适用本申请的通信系统的示意性架构图；
图2是本申请提供的一种建立会话的方法的示意性流程图；
图3是本申请提供的另一种建立会话的方法的示意性流程图；
图4是本申请提供的再一种建立会话的方法的示意性流程图；
图5是本申请提供的一种获取第一对应关系的方法的示意性流程图；
图6是本申请提供的一种建立会话的信息交互图；
图7是本申请提供的另一种建立会话的信息交互图；
图8是本申请提供的再一种建立会话的信息交互图；
图9是本申请提供的再一种建立会话的信息交互图；
图10是本申请提供的再一种建立会话的信息交互图；
图11是本申请提供的再一种建立会话的信息交互图；
图12是本申请提供的一种可能的AN的结构示意图；
图13是本申请提供的另一种可能的AN的结构示意图；
图14是本申请提供的一种可能的AMF的结构示意图；
图15是本申请提供的另一种可能的AMF的结构示意图。
具体实施方式
下面将结合附图，对本申请中的技术方案进行描述。
图1示出了一种适用本申请的通信系统。该通信系统包括UE110、UE120、AN130、UPF140、AMF150、SMF160和DN170。UE110和UE120分别通过无线网络与AN130进行通信，AN130、UPF140、AMF150、SMF160以及DN170之间可以通过相应的核心网接口(图1中所示的连线)进行通信。上述各网元均为实体设备。在本申请中，AN也可称为AN设备，SMF也可称为SMF设备、SMF网元或SMF实体，AMF也可称为AMF设备、AMF网元或AMF实体。
AN130与UPF140之间的通信连接可称为隧道。一个隧道可以承载一个或者多个会话。只承载一个会话的隧道对应会话粒度的用户面模型。承载多个会话的隧道对应聚合型的用户面模型。该多个会话可以属于同一个UE，也可以属于不同的UE。可选的，一个UE可同时通过会话粒度的隧道和聚合性的隧道访问数据网络。
如图1所示，隧道1承载三个会话，该三个会话分别为会话1、会话2和会话3，其中，会话1和会话2属于UE110，会话3属于UE120。由于隧道1承载多个会话，因此，AN130与UPF140之间的用户面模型称为聚合型用户面模型。
在本申请中，UE可称为终端设备、接入终端、用户单元、用户站、移动站、移动台、远方站、远程终端、移动设备、用户终端、终端、无线通信设备、用户代理或用户装置。UE可以是蜂窝电话、具有无线通信功能的手持设备、计算设备或连接到无线调制解调器的其它处理设备、车载设备、可穿戴设备以及第五代(5th-generation，5G)通信系统中的用户设备。
AN可以是码分多址(code division multiple access，CDMA)系统中的基站(base transceiver station，BTS)，也可以是宽带码分多址(wideband code division multiple access，WCDMA)系统中的基站(node B，NB)，还可以是长期演进(long term evolution，LTE)系统中的演进型基站(evolutional node B，eNB)，还可以是5G通信系统中的基站(gNB)， 上述基站仅是举例说明，AN还可以为中继站、接入点、车载设备、可穿戴设备以及其它类型的设备。
AMF可负责UE的附着、移动性管理、跟踪区更新流程等。
SMF实体可负责UE的会话管理，UPF的选择、重选，IP地址分配，服务质量(quality of service，QoS)，以及会话的建立、修改和释放。其中，在5G系统中，SMF实体和AMF实体之间通过N11接口相连。SMF实体与UPF之间通过N4接口相连。AMF实体和AN之间通过N2接口相连。在以下描述中，通过N11接口传输的消息可称为N11消息。通过N4接口传输的消息可称为N4消息。通过N2接口传输的消息可称为N2消息。此外，这些消息，在不同的场景下，还可具有其他名称，本申请并不在此限制。
UPF连接至DN，用于在该UPF的服务区域实现业务的数据传输。
上述适用本申请的通信系统仅是举例说明，适用本申请的通信系统不限于此，例如，通信系统中包括的AN、AMF、SMF、UPF、DN和UE的数量还可以是其它的数量。AN、AMF、SMF、DN和UE还可能有其它的名称，在本申请中，使用AN、AMF、SMF、UPF、DN和UE并不意味着对本申请保护范围的限定。
为了便于理解本申请，首先对本申请涉及的概念做详细介绍。
AMF主要负责UE的移动性管理，如位置更新、注册网络、切换等。在图1所示的场景下，当UE与DN之间建立会话之后，AMF150上保存的UE的上下文信息主要包括：UE标识、会话标识、SMF标识。
SMF主要负责UE的会话管理，如会话建立、修改、释放，具体功能如为用户分配IP地址、选择提供报文转发功能的UPF等。在图1所示的场景下，当UE与DN之间建立会话之后，SMF160上保存的会话的上下文信息主要包括：会话标识、会话对应的服务质量(quality of service，QoS)参数。例如，QoS参数包括：分配和保留优先级(allocation and retention priority，ARP)，会话粒度的聚合最大比特率(per session aggregate maximum bit rate，session-AMBR)，UE粒度的聚合最大比特率(per UE aggregate maximum bit rate，UE-AMBR)。可选地，一个会话可能包括多个业务流，各个业务流可能具有不同的QoS参数。
AN主要负责为UE提供无线接入的设备。在图1所示的场景下，当UE与DN之间建立会话之后，AN130上保存的上下文主要包括与该会话对应的：UE与AN之间的无线连接信息(例如数据无线承载(data radio bearer，DRB)标识)、AN与UP之间的隧道连接信息(例如UPF侧隧道标识)、UE的IP地址、QoS参数。
聚合型用户面模型可以包含多个会话。为了与会话粒度的用户面模型做对比，在介绍本申请提供的建立会话的方法之前，先结合图2介绍会话粒度的用户面模型的管理方法。
当一个隧道只承载一个会话时，该用户面模型称为会话粒度的用户面模型。对于会话粒度的用户面模型，当会话被去激活时(如UE进入空闲态，或UE处于连接态但UE的该会话被去激活时)，AN与UPF之间的隧道断开。当UPF接收到该会话的下行数据时，通信系统需要重新建立(即，恢复)该下行数据对应的会话，恢复会话的流程如图2所示。图2所示的恢复会话的方法包括以下步骤：
S201，UPF接收到下行数据后，向SMF发送数据通知(data notification)，以通知SMF有下行数据需要发送。
S202，SMF收到数据通知后，向AMF发送N11消息，该N11消息携带会话标识、QoS参数、UPF侧隧道信息。例如，UPF侧隧道信息是UPF的IP地址和/或UPF侧隧道端点标识。
S203，AMF保存有当前UE的状态，AMF根据UE的状态，确定是否执行S204。当UE处于空闲态时，则AMF向AN发送寻呼(paging)消息，AN根据该寻呼消息触发寻呼流程并执行步骤S204。当UE处于连接态时，AMF不需要寻呼UE，直接执行S205。
S204，UE接收到寻呼消息，UE通过AN向AMF发送服务请求。该服务请求是寻呼消息的响应消息。
S205，AMF向AN发送上下文建立请求，该上下文建立请求携带S202中的会话标识、QoS参数和UPF侧隧道信息。
S206，AN根据接收到的上下文建立请求，触发UE与AN之间的无线连接建立过程。
S207，AN向AMF发送UE的上下文建立响应，该上下文建立响应携带AN侧隧道信息。例如，该AN侧隧道信息是AN IP地址和/或AN侧隧道端点标识。
S208，AMF向SMF发送N11消息，该N11消息携带上述会话标识和AN侧隧道信息。
S209，SMF向UPF发起用户面路径修改过程。例如，SMF向UPF发送携带上述会话标识和AN侧隧道信息的用户面路径修改请求；UPF返回用户面路径修改响应。
此时，UE与DN之间的会话恢复成功，UPF通过AN与UPF之间的用户面隧道以及UE与AN之间的DRB向UE发送会话对应的下行数据。
本申请中，AMF与SMF之间的接口称为N11接口，因此二者之间的消息交互可以简单的称为N11消息。对于具体消息名称，本发明不做限定。
对于聚合型用户面模型，例如图1所示的用户面模型，某个会话被去激活不会影响AN与UP之间的隧道连接。如，会话1被去激活，但隧道1不会断开。当UPF接收到会话1对应的下行数据时，UPF会将该下行数据通过UPF与AN之间的用户面隧道直接发送至AN。由于AN在会话1被去激活时已清空会话1的全部信息，包括AN与UE之间的DRB信息，因此，当AN接到该下行数据时，无法确定该下行数据对应哪个DRB，也就无法将该下行数据发送给UE，从而导致AN丢弃该下行数据，降低了用户体验。
下面，将结合图1详细分析上述问题产生的原因。
对于UE的一个会话，当UE与AN、AN与UP之间存在用户面连接时，即UE的数据可以传输时，该会话处于激活状态(activation)。当UE与AN之间不存在用户面连接，但SMF上保存会话的上下文，如UE的IP地址、会话标识等时，则该会话处于去激活状态(deactivation)。对于处于去激活状态的会话，AN上保存的该会话的信息将全部删除。
例如，AN130上保存的上下文信息如表1所示：
表1
会话1 无线连接信息1 隧道连接信息1 UE IP1 QoS参数1
会话1 无线连接信息2 隧道连接信息1 UE IP1 QoS参数2
会话2 无线连接信息3 隧道连接信息1 UE IP2 QoS参数1
会话3 无线连接信息4 隧道连接信息1 UE IP3 QoS参数1
以会话1为例。在会话1被去激活前，若下行数据通过隧道连接信息1对应的隧道1到达AN，且该下行数据携带QoS参数1，则根据表1，AN可根据上下文信息中的隧道连接信息1和QoS参数1，确定该下行数据为会话1的下行数据，通过无线连接信息1对应的DRB1将该下行数据发送至UE110。
在图1所示的场景下，当会话1被去激活时，AN130上会话1的相关信息被全部删除，AN130保存的上下文信息将变为如表2所示：
表2
会话2 无线连接信息3 隧道连接信息1 UE IP2 QoS参数1
会话3 无线连接信息4 隧道连接信息1 UE IP3 QoS参数1
当会话1被去激活后，对于上述情况，当会话1的下行数据到达时，UPF140将下行数据通过隧道1发送给AN130，但由于AN130没有该下行数据对应的无线连接信息，因此AN130无法将下行数据发送给UE。那么，该下行数据将被丢弃，导致用户体验下降。
本申请针对上述问题，提出一种解决方案：由AMF保存UE IP地址、隧道标识信息(如隧道标识、AN侧的隧道信息和UPF侧的隧道信息)与UE标识、会话标识以及SMF标识之间的关联。例如，在图1所示的场景下，AMF150上保存的UE的上下文为：
UE110 会话1 SMF160 UE IP1 隧道标识信息1
UE110 会话2 SMF160 UE IP2 隧道标识信息1
UE120 会话3 SMF160 UE IP3 隧道标识信息1
按照上述解决方案的思路，图3示出了本申请提供的一种建立会话的方法300的示意性流程图。该方法300包括：
S310，AN从UPF接收第一下行数据，所述第一下行数据包括第一UE IP地址和第一隧道标识信息。
S320，所述AN向AMF发送第一消息，所述第一消息包括所述第一UE IP地址和所述第一隧道标识信息。
S330，所述AN从所述AMF接收第二消息，所述第二消息包括用于建立第一会话的上下文，所述第一会话为与所述第一UE IP地址和所述第一隧道标识信息对应的会话。所述AN根据接收到的第二消息，恢复UE与AN之间的无线连接，从而使得AN将第一下行数据可以发送给UE。
在S310中，第一下行数据为UPF发送的任意一个下行数据，AN接收到第一下行数据后，从中解析出第一UE IP地址和第一隧道标识信息。
例如，第一隧道标识信息为传输该第一下行数据的隧道的标识(即，隧道标识)，或者，第一隧道标识信息为传输该第一下行数据的隧道在AN侧的隧道信息，或者，第一隧道标识信息为传输该第一下行数据的隧道在UPF侧的隧道信息，或者，第一隧道标识信息包括隧道标识、AN侧的隧道信息和UPF侧的隧道信息中的至少两种。例如，AN侧隧道信息包括AN IP地址和/或AN侧隧道端点标识。UP侧隧道信息包括UP IP地址和/或UP侧隧道端点标识。上述示例仅是举例说明，第一隧道标识信息用于标识传输第一下行数据的隧道，本申请对第一隧道标识信息的具体内容不做限定。
AN接收到该第一下行数据后，由于AN上没有该第一下行数据对应的无线连接信息，因此无法将该第一下行数据发送给UE。根据本申请描述的方法，AN向AMF发送第一消 息，第一消息包括第一UE IP地址和第一隧道标识信息，以便于AMF确定与第一UE IP地址和第一隧道标识信息对应的会话。此外，UE IP地址也可简称为UE IP。
第一消息可以是通知消息，通知消息用于将AN收到了包括第一UE IP地址和第一隧道标识信息的下行数据的情况通知给AMF。或者，第一消息也可以是请求消息，请求消息用于请求获取与第一UE IP地址和第一隧道标识信息对应的会话的信息。AMF接收到第一消息后可以通过第三消息将第一会话(即，第一UE IP地址和第一隧道标识信息对应的会话)的信息发送给AN，也可以将第一UE(即，第一会话所属的UE)的部分或全部会话的信息发送给AN。
例如，第一会话所属的UE的部分或全部会话的信息包括：UE IP地址、隧道标识信息和会话标识三者之间的对应关系。例如，UE的会话的信息包括第一对应关系和第二对应关系，第一对应关系包括第一UE IP地址、第一隧道标识信息和第一会话的标识三者之间的第一对应关系；第二对应关系包括第二UE IP地址、第二隧道标识信息和第二会话的标识三者之间的第二对应关系。其中，第一会话和第二会话可以是UE的全部会话，也可能只是UE的部分会话。需要说明的一点是，上述第一对应关系或第二对应关系还可以包括：UE标识、SMF标识与上述参数之间的对应关系。其中，SMF标识用于标识SMF。
此外，AN向AMF发送第一消息后，从AMF接收第二消息。第二消息为携带用于建立第一会话的上下文的消息。本申请对第一消息以及第二消息的具体名称不作限定。通过本申请的方法，在AN接收到下行数据时，可从AMF获取到该下行数据所属的第一会话的上下文信息，从而恢复该第一会话在UE和AN之间的无线连接，避免了AN因为没有该下行数据对应的无线连接而丢弃该下行数据，降低用户体验的现象。
以下，分别以第一消息为通知消息和请求消息为例对本申请的技术方案进行描述。
情况1，
当第一消息为通知消息时，AMF根据第一对应关系确定与第一UE IP地址和第一隧道标识信息对应的第一会话的信息。例如，第一会话的信息可以是第一会话的标识。例如，AMF可以以表格的形式保存上述第一对应关系，通过查询表格的方式确定第一会话的信息。此外，AMF也可以通过其它方式确定第一会话的信息，本申请对第一对应关系的具体形式以及AMF确定第一会话的具体方式不作限定。
此外，第一对应关系还可包括第一会话所属的UE(即，第一UE)和与第一会话相关的SMF。AMF可以根据第一消息中携带的第一UE IP地址和第一隧道标识信息，以及第一对应关系，确定第一会话所属的UE(即，第一UE)，根据第一UE的状态进行第一会话的恢复流程。
(1)当第一UE处于空闲(idle)态时，AMF发起寻呼流程，寻呼第一UE，具体的寻呼流程可参考现有技术中寻呼UE的流程，在此不再赘述。上述空闲态也可称为连接管理空闲(connection management idle，CM-IDLE)态。
第一UE被寻呼到后，AMF向第一SMF(即，管理第一会话的SMF)发送会话上下文获取请求，该会话上下文获取请求携带第一会话的标识。随后，AMF从第一SMF接收会话上下文获取响应，该会话上下文获取响应携带建立第一会话所需的上下文，例如第一会话的QoS参数。AMF向AN发送会话上下文建立请求，该上下文建立请求携带建立第一会话所需的上下文。AN根据该上下文与第一UE建立空口连接，并向AMF发送会话上 下文建立响应。
(2)当第一UE处于连接(connected)态时，AMF可以直接向第一会话对应的SMF(即，第一SMF)发送会话上下文获取请求，后续步骤与情况(1)中AMF的处理步骤相同，在此不再赘述。上述连接态也可称为连接管理连接(connection management connected，CM-CONNECTED)。
需要说明的一点是，AMF接收到通知消息后，还可以将保存的第一UE的对应关系(包括但不限于第一对应关系)发送给AN。这样，当AN接收到第一UE的其它会话对应的下行数据(例如，第二下行数据)时，可以直接根据上述对应关系确定第二下行数据对应的第二会话，从而AN通过AMF向第二会话对应的SMF获取第二会话的上下文，进而更加快速地恢复第二会话对应的UE与AN之间的无线连接，使得AN将第二下行数据发送给UE。
情况2，
当第一消息为请求消息时，AMF根据第一对应关系确定与第一UE IP地址和第一隧道标识信息对应的会话确定第一会话的信息。例如，第一会话的信息可以是第一会话的标识。例如，AMF可以以表格的形式保存上述第一对应关系，并通过查询表格的方式确定第一会话和第一UE的信息。此外，AMF也可以通过其它方式确定第一会话的信息，本申请对第一对应关系的具体形式以及AMF确定第一会话的具体方式不作限定。
随后AMF向AN发送第三消息，第三消息携带第一UE对应的部分或全部会话的信息。例如，第三消息可以携带第一对应关系和第二对应关系。第一对应关系包括第一UE IP地址、第一隧道标识信息和第一会话的标识三者之间的第一对应关系；第二对应关系包括第二UE IP地址、第二隧道标识信息和第二会话的标识三者之间的第二对应关系。其中，第一对应关系和第二对应关系可以是第一UE的全部会话的信息(例如，第一UE只包括第一会话和第二会话)，或者，第一对应关系和第二对应关系仅是第一UE的部分会话的信息(例如，第一UE至少包括3个会话)。这样，当AN接收到第一UE的其它会话对应的下行数据(例如，第二下行数据)时，可以直接根据上述对应关系确定第二下行数据对应的第二会话，从而AN通过AMF向第二会话对应的SMF获取第二会话的上下文，进而更加快速地恢复第二会话对应的UE与AN之间的无线连接，使得AN将第二下行数据发送给UE。
另外，AMF还保存UE标识、SMF标识与会话标识的对应关系，因此，第三消息可携带UE IP、隧道标识、会话标识、UE标识和SMF标识之间的对应关系。
AN根据第三消息中的对应关系，判断第一UE是否存在处于激活状态的会话，从而判断UE的状态。对于处于激活状态的会话，AN保存有该会话对应的空口连接信息。其中，会话的空口连接信息指的是UE与AN之间的无线连接。因此，当AN保存的第一UE的会话信息中没有会话的空口连接信息时，AN判断UE处于空闲状态。例如，如果第一UE存在处于激活状态的会话，则AN判断第一UE处于连接态；如果第一UE不存在处于激活状态的会话，则AN判断UE处于空闲态。随后，AN根据第一UE的状态进行会话恢复的流程。如下所述：
(3)当第一UE处于空闲态时，AN发起寻呼流程，寻呼第一UE，具体的寻呼流程可参考现有技术中寻呼UE的流程，在此不再赘述。
第一UE被寻呼到后，AN通过AMF向第一SMF发送会话上下文获取请求，该会话上下文获取请求携带第一会话的标识；随后，AN通过AMF从第一SMF接收会话上下文获取响应，该会话上下文获取响应携带建立第一会话所需的上下文，例如第一会话的QoS参数；AN根据该上下文与第一UE建立空口连接。
(4)当第一UE处于连接态时，AN不需要寻呼UE，根据保存的第一对应关系，确定第一下行数据对应的会话，通过AMF向第一会话对应的第一SMF发送会话上下文获取请求，后续步骤与情况(3)中AN的处理步骤相同，在此不再赘述。
第一会话恢复后，AN即可向第一UE发送第一下行数据。
需要指出的是，在本申请中，“当…时”、“若”以及“如果”均指在某种客观情况下UE或者AN会做出相应的处理，并非是限定时间，且也不要求UE或AN实现时一定要有该判断的动作，也不意味着存在其它限定。
可选的，当第一消息为通知消息时，第三消息可以是该通知消息的响应消息；当第一消息为请求消息时，第三消息可以是该请求消息的响应消息。当第一消息为通知消息时，AMF也可以不发送该通知消息的响应消息。
此外，同一个消息的名字可能有多种叫法，本申请中各个消息的名字仅是举例说明，不应被理解为对本申请的技术方案的限定，各个消息的名字应以其实际作用为准。
综上所述，本申请提供的建立会话的方法300，AN通过向AMF发送第一UE IP地址和第一隧道标识信息，并接收AMF发送的用于恢复第一会话的上下文，从而可以恢复与第一UE IP地址和第一隧道标识信息对应的第一会话。
可选地，方法300还包括：
S340，所述AN从所述AMF接收第三消息，所述第三消息包括所述第一会话的标识、所述第一UE IP地址和所述第一隧道标识信息之间的第一对应关系，所述第三消息还包括第二会话的标识、第二UE IP地址和第二隧道标识信息之间的第二对应关系。
第二对应关系中，第二会话为第一UE对应的全部会话中与第一会话不同的会话中的任意一个会话。
可选地，方法300还包括：
S350，所述AN从所述UPF接收第二下行数据，所述第二下行数据包括所述第二UE IP地址和所述第二隧道标识信息。
S360，所述AN根据保存的第一UE的会话信息、以及第二UE IP地址和第二隧道标识信息，确定第二下行数据对应的会话(即，第二会话)，向所述AMF发送第四消息，所述第四消息包括所述第二会话的标识。所述AMF根据会话标识与SMF标识的对应关系，向第二会话标识对应的SMF发送上下文获取请求，以获取第二会话对应的上下文。
可选地，当AN保存的对应关系包括SMF标识时，所述AN通过AMF直接向第二会话对应的SMF发送会话上下文获取请求，以获取第二会话对应的上下文。
AMF接收SMF返回的会话上下文获取响应，该会话上下文获取响应携带第二会话的上下文，如第二会话对应的QoS参数。
S370，所述AN从所述AMF接收第五消息，所述第五消息包括用于建立所述第二会话的上下文。
第二下行数据为与第一下行数据对应UE不同的会话，AN接收到第二下行数据后， 根据第二下行数据包括第二UE IP地址和第二隧道标识信息确定第一UE，并根据从AMF接收到的对应关系确定第二UE IP地址和第二隧道标识信息对应的会话(即，第二会话)，随后进行第二会话的恢复流程。从而解决了当通信系统采用聚合型用户面模型时，如何实现会话粒度的会话管理(即，会话激活)，例如，当去激活的会话有新的下行数据需要传输时，UPF会将新的下行数据直接发送至AN，AN接收到新的下行数据后，根据保存的UE的会话信息，确定新的下行对应的会话，从而通过AMF向SMF获取该会话对应的会话上下文，从而恢复该会话对应的UE与AN之间的无线连接，使得AN可以将新的下行数据发送给UE。也就是说，AN可以根据本申请提供的建立会话的方法向UE发送该新的下行数据，从而避免了AN因无法向UE发送该新的下行数据而丢弃该新的下行数据，提高了用户体验。
第四消息为携带第二会话的标识的消息，第五消息为携带用于重新建立第二会话的上下文的消息，本申请对第四消息和第五消息的名字不作限定。
图4示出了本申请提供的一种建立会话的方法400的另一示意性流程图。该方法400包括：
S410，AMF从AN接收第一消息，所述第一消息包括第一UE IP地址和第一隧道标识信息。
S420，所述AMF向所述AN发送第二消息，所述第二消息包括用于建立第一会话的上下文，所述第一会话为与所述第一UE IP地址和所述第一隧道标识信息对应的会话。
本领域技术人员可以清楚地了解到：在方法400中，AMF和AN均可等同于方法300中的AMF和AN，且AMF和AN的动作与方法300中的AMF和AN的动作相对应，此外，第一消息、第二消息也与方法300中的第一消息、第二消息相同，为了简洁，在此不再赘述。
因此，本申请提供的建立会话的方法400，AMF从AN接收第一UE IP地址和第一隧道标识信息，并向AN发送用于建立第一会话的上下文，从而可以建立与第一UE IP地址和第一隧道标识信息对应的第一会话。
可选地，方法400还包括：
S430，若第一UE处于空闲态，所述AMF向AN发送寻呼消息，以寻呼所述第一UE。所述第一UE为与所述第一UE IP地址和所述第一隧道标识信息对应的UE。
可选地，方法400还包括：
S440，所述AMF向所述AN发送第三消息，所述第三消息包括所述第一会话的标识、所述第一UE IP地址和所述第一隧道标识信息之间的第一对应关系，所述第三消息还包括第二会话的标识、第二UE IP地址和第二隧道标识信息之间的第二对应关系。
第三消息可以仅携带第一对应关系，也可以携带第一对应关系和第二对应关系，第二对应关系中，第二会话为第一UE对应的全部会话中与第一会话不同的会话中的任意一个会话。
从而，解决了当通信系统采用聚合型用户面模型时，如何实现会话粒度的会话管理(即，会话激活)，例如，当去激活的会话有新的下行数据需要传输时，UPF会将新的下行数据直接发送至AN，AN接收到新的下行数据后根据保存的UE的会话信息，确定新的下行对应的会话，从而通过AMF向SMF获取该会话对应的会话上下文，从而恢复该会话 对应的UE与AN之间的无线连接，使得AN可以将新的下行数据发送给UE。也就是说，AN可以根据本申请提供的建立会话的方法向UE发送该新的下行数据，从而避免了AN因无法向UE发送该新的下行数据而丢弃该新的下行数据，提高了用户体验。
可选地，方法400还包括：
S450，所述AMF从所述AN接收第四消息，所述第四消息包括所述第二会话的标识。
S460，所述AMF向所述AN发送第五消息，所述第五消息包括用于恢复所述第二会话的上下文。
方法400中，第三消息、第四消息和第五消息与方法300中第三消息、第四消息和第五消息相同，为了简洁，不再赘述。
可选地，方法400还包括：
S470，所述AMF从SMF获取所述第一UE IP地址、所述第一隧道标识信息与所述第一会话的标识之间的第一对应关系。
图5示出了本申请提供的一种AMF获取第一对应关系的方法的示意性流程图。例如，AMF在会话建立过程中获取第一对应关系。该方法500包括：
S501，UE通过AN向AMF发送会话建立请求(session setup request)，以请求建立会话。该会话建立请求携带会话标识(即，第一会话的标识)以及数据网络名称(data network name，DNN)。
S502，AMF选择为该UE提供会话管理服务的SMF，并保存会话标识与SMF标识的对应关系。
S503，AMF向该SMF发送N11消息。该N11消息可以是携带会话建立请求的会话管理请求(session management request，SM request)。该会话建立请求携带会话标识和DNN。
S504，SMF接收到N11消息后，判断AN与UPF之间是否有用户面路径。当AN与UPF之间没有用户面路径时，发起用户面路径建立过程。例如，SMF分配隧道标识，为UE分配IP地址，向UPF发送N4会话建立请求(N4 session setup request)，该N4会话建立请求携带会话标识、DNN、和隧道标识。可选地，当SMF上预配置有聚合型的用户面模型的信息时，该N4会话建立请求还可携带AN侧隧道信息。SMF从UPF接收N4会话建立响应，该N4会话建立响应携带UP侧隧道信息和隧道标识。其中，AN侧隧道信息包括AN IP地址和/或AN侧隧道端点标识。UP侧隧道信息包括UP IP地址和/或UP侧隧道端点标识。
S505，SMF向AMF发送N11消息，该N11消息携带第一对应关系，即，第一隧道标识信息、第一UE IP地址、第一会话的标识之间的对应关系。其中，第一隧道标识信息为UP侧隧道信息、AN侧隧道信息和隧道标识中的至少一个。该N11消息还可以携带其它信息，例如，QoS参数。
S506，AMF保存上述第一对应关系。
此时，AMF上保存的信息包括UE标识、第一会话对应的SMF标识、第一隧道标识信息、第一UE IP地址、第一会话的标识之间的对应关系。其中，UE标识用于唯一标识一个终端用户，AMF在UE注册到数据网络的过程中保存该UE标识。
S507，AMF向AN发送N2消息，该N2消息携带会话标识、UE IP和QoS参数，该 N2消息用于请求AN建立无线承载。
S508，AN发起无线承载建立流程。
S509，AN向AMF发送N2消息，该N2消息用于表示无线承载已经建立。
上述AMF获取第一对应关系的实施例仅是举例说明，本申请不限于此，例如，还可以通过预配置的方式在AMF中配置第一对应关系。
从而，当AMF接收到AN发送的包括第一UE IP地址和第一隧道标识信息的第一消息时，可以根据第一对应关系确定第一UE IP地址和第一隧道标识信息对应的第一会话，进而重新建立第一会话。
可选地，第一隧道标识信息为传输第一下行数据的隧道的标识(即，隧道标识)、AN侧的隧道信息和UPF侧的隧道信息中的至少一种。上述示例仅是举例说明，第一隧道标识信息用于标识传输第一下行数据的隧道，本申请对第一隧道标识信息的具体内容不做限定。
当UE建立第二会话时，AMF更新保存的信息，添加第二会话相关的会话信息。例如，AMF上保存的信息更新后包括：
UE标识、第一会话对应的SMF标识、第一隧道标识信息、第一UE IP地址、第一会话的标识之间的对应关系，以及，
UE标识、第二会话对应的SMF标识、第二会话对应的隧道标识信息(例如，第二隧道标识信息)、第二会话对应的UE IP地址(例如，第二UE IP地址)、第二会话的标识之间的对应关系。
为了更清晰地描述本申请提供的建立会话的方法，下面，将结合上述内容介绍本申请提供的建立会话的信息交互图。
如图6所示，在该方法中，AMF保存对应关系，且当需要寻呼UE时，由AMF触发寻呼流程。该方法包括：
S601，AN从UPF接收下行数据，下行数据包括UE IP地址和隧道标识信息(即，会话信息)。
S602，由于AN没有保存上述下行数据对应的无线连接信息，因此，AN向AMF发送通知消息，该通知消息携带S601中的会话信息。
S603，AMF根据保存的对应关系(即，UE标识-会话信息-会话标识-SMF标识)确定接收到的会话信息对应的会话、UE以及SMF。
随后，AMF根据会话信息对应的UE的不同状态执行下述不同步骤。
当UE处于空闲态时(AMF可以根据保存的UE上下文判断UE的状态，此处为现有技术，不再赘述)，AMF触发寻呼流程，执行S604至S606。
S604，AMF向AN发送寻呼消息，该寻呼消息携带寻呼标识，该寻呼标识用于标识UE。
可选地，AMF可以向AN发送与该UE相关的全部或部分对应关系，以便于当AN再次从UPF接收到该UE的其它会话的下行数据时，可以直接根据保存在该AN中的对应关系，确定下行数据对应的会话，从而获取到该会话对应的会话上下文，无需再向AMF发送通知消息，也无需由AMF确定该下行数据对应的会话，从而减轻了AMF的负担。例如，AMF可以通过寻呼消息向AN发送与该UE相关的全部或部分对应关系，也可以通过 除寻呼消息之外的其他消息向AN发送与该UE相关的全部或部分对应关系。
S605，AN根据接收到的寻呼消息寻呼UE。
S606，被寻呼到的UE发起服务请求流程，以恢复会话。例如，该服务请求流程可以包括S607～S611。
当UE处于连接态时(AMF可以根据保存的UE上下文判断UE的状态，此处为现有技术，不再赘述)，AMF触发上下文建立流程，例如，执行S607。
S607，AMF向与会话信息对应的SMF发送会话上下文获取请求，该会话上下文获取请求携带有会话标识。
S608，SMF向AMF发送会话上下文获取响应，该会话上下文获取响应携带会话标识对应的会话上下文，该会话上下文例如可以是会话的QoS信息。
S609，AMF向AN转发会话上下文建立请求，该会话上下文建立请求携带S608中的会话上下文。
S610，AN触发UE与AN之间的无线连接建立流程。
需要说明的是，SMF将确定的会话上下文，通过AMF的转发发送给AN后，AN根据收到的会话上下文，建立AN与UE之间的DRB。因此，AMF可以无须理解SMF发送的会话上下文。
S611，AN向AMF发送会话上下文建立响应。
图7示出了本申请提供的另一种建立会话的信息交互图。在图7所示的方法中，AMF将对应关系传递至AN，并由AN保存对应关系。当需要寻呼UE时，由AN触发寻呼流程。该方法包括：
S701，AN从UPF接收下行数据，并从该下行数据中获取到UE IP地址和隧道标识信息(即，会话信息)。
S702，由于AN没有保存上述下行数据对应的无线连接信息，因此，AN向AMF发送请求消息，该请求消息携带S701中的会话信息。该请求消息用于请求AMF将该会话信息对应的UE的对应关系发送给AN。
S703，AMF根据保存的对应关系(即，UE标识-会话信息-会话标识-SMF标识)确定接收到的会话信息对应的会话、UE以及SMF，并向AN发送响应消息，该响应消息携带上述对应关系，以便于AN保存该对应关系并根据该对应关系建立S701中下行数据对应的会话。
可选地，S703中的响应消息可以携带与S703中所述UE相关的其它对应关系(例如，UE的全部或部分对应关系)，以便于当AN再次从UPF接收到属于该UE其它会话的下行数据时，可以直接根据保存在该AN中的对应关系，确定下行数据对应的会话，从而获取到该会话对应的会话上下文。
随后，AN根据会话信息对应的UE的不同状态执行下述不同步骤。需要说明的是，AN根据该AN中保存的UE的上下文信息判断UE的状态，一种实现方式为：当AN中保存的UE的上下文信息中，具有无线连接信息时，则AN判断UE处于连接态；反之，AN判断UE处于空闲态。
当UE处于空闲态时(AN可以根据AN中保存的UE的上下文信息判断UE的状态)，AN触发寻呼流程，执行S704。
S704，AN寻呼UE。
S705，被寻呼到的UE发起服务请求流程，以恢复会话。例如，该服务请求流程可以包括S706～S708。
当UE处于连接态时(AN可以根据AN中保存的UE的上下文信息判断UE的状态)，AN触发上下文建立流程，执行S706。
S706，AN通过AMF向与会话信息对应的SMF发送会话上下文获取请求，该会话上下文获取请求携带有会话标识。
S707，SMF通过AMF向AN发送会话上下文获取响应，该会话上下文获取响应携带用于建立会话的上下文，该上下文例如可以是会话的QoS信息。
S708，AN触发UE与AN之间的无线承载建立流程。
S709，AN向SMF发送会话上下文建立响应。
图8示出了本申请提供的再一种建立会话的信息交互图。在图8所示的方法中，AMF将对应关系传递至AN，并由AN保存对应关系。当需要寻呼UE时，由AMF触发寻呼流程。该方法包括：
S801，AN从UPF接收下行数据，并从该下行数据中获取到UE IP地址和隧道标识信息(即，会话信息)。若该AN保存有该会话信息对应的UE的无线连接信息，则AN判断该UE处于连接态，此时，AN可以直接通过AMF向SMF索取会话上下文，以便于恢复接收到的下行数据对应的会话。
S802，若该AN没有该会话信息对应的UE的无线连接信息，则AN判断该UE处于空闲态，此时，由于AN无法确定上述会话信息属于哪个会话，也就无法确定上述下行数据对应的无线连接信息，因此，AN向AMF发送请求消息，该请求消息携带S801中的会话信息。该请求消息用于通知AMF有下行数据发送到AN，且用于请求AMF将该会话信息对应的UE的全部或部分对应关系发送给AN。
需要说明的是，S801～S802还可以替换为如下步骤：S801’，SMF收到UPF发送的激活会话请求，携带会话标识。该激活会话请求，用于触发SMF恢复会话对应的连接。S802’，SMF向AMF发送N11消息，携带会话信息。其中，会话信息包括会话对应的QoS参数、UPF的隧道信息等。此时，如果AMF判断UE处于空闲态，则AMF寻呼UE，并将UE的全部或部分对应关系发送给AN。如果AMF判断UE处于连接态，则AMF将会话信息发送给AN，触发AN根据该会话信息恢复AN与UE之间的DRB连接。也就是说，AMF将UE的全部或部分对应关系发送给AN，可以是由聚合型的用户面模型场景下的AN发送的请求消息触发的，或者，也可以是由会话粒度的用户面模型下SMF发送的N11消息触发的。
S803，AMF根据从AN接收到的会话信息，以及保存的对应关系(即，UE标识-会话信息-会话标识-SMF标识)确定接收到的会话信息对应的会话、UE以及SMF。此外，AMF通过寻呼消息，或者除寻呼消息之外的其它消息，将UE的对应关系发送给AN。
S804，AMF可以在确定会话信息对应的UE后触发寻呼流程，即，AMF向AN发送寻呼消息。
S805，AN向UE发送寻呼消息。
S806，UE被寻呼到之后，UE发起服务请求流程。例如，UE向AMF发送服务请求 消息，AMF接收服务请求消息，向与S801中所述的会话信息对应的SMF发送会话上下文获取请求，该会话上下文获取请求携带有会话标识。
当AN再次收到UE的其它会话的下行数据时，AN根据保存的UE的对应关系触发上下文建立过程，执行S807。
S807，AN根据保存的UE的对应关系，以及下行数据中的UE IP地址和隧道标识信息，确定该下行数据对应的会话标识，AN通过AMF向该会话标识对应的SMF发送会话上下文获取请求，携带会话标识。
S808，SMF通过AMF向AN发送会话上下文获取响应，携带会话标识对应的会话上下文。该会话上下文可以是会话的QoS信息、UPF的隧道信息等。
需要说明的是，由于SMF确定的会话上下文用于发送给AN，使得AN建立AN与UE之间的DRB。因此，AMF无须理解SMF发送的会话上下文，也就是说，AMF向AN转发会话上下文。
S809，AN根据接收到的会话上下文触发UE与AN之间的无线连接建立流程。
图9～图11给出了异常情况下AN和AMF的操作。
图9示出了本申请提供的再一种建立会话的信息交互图。图9所示的方法描述了AN接收到UE的对应关系之前，再次收到下行数据时场景，该方法包括：
S901，AN从UPF接收会话1的下行数据，并从中获取到UE IP地址和隧道标识信息(即，会话信息)。应理解，“会话1”仅用于标识该下行数据所属的会话，以便于与S903中的下行数据区分开，此时AN并不知道该下行数据属于哪个会话。
S902，由于AN没有保存上述下行数据对应的无线连接信息，因此，根据图6～图8所示的方法，AN向AMF发送通知消息或请求消息。该通知消息携带S901中的会话信息，并用于通知AMF该AN收到了该会话信息对应的下行数据。该请求消息携带从会话1的下行数据中会话信息，用于请求AMF将该会话信息的对应关系发送给该AN。
S903，AN从UPF接收到会话2的下行数据。
此时，AN的处理方法有两种，可以选择执行S904，也可以选择执行S905。
S904，AN缓存会话2的下行数据，不发送通知消息或请求消息。待收到AMF针对S902中的通知消息或请求消息发送的响应消息时，根据该响应消息中携带的对应关系，对会话1和会话2的下行数据进行处理。以图7所示的方法(AN寻呼且AN保存对应关系)为例，具体的处理过程为：AN根据对应关系，确定下行数据对应的会话标识，即会话1和会话2；AN判断UE的状态，决定寻呼UE或者通过AMF直接向会话标识对应的SMF请求会话1对应的会话上下文以及会话2对应的会话上下文。
当AN选择执行S905时，即，AN向AMF发送通知消息或请求消息，该通知消息或该请求消息携带从会话2的下行数据中解析出的会话信息，此时，AMF可以执行S906。
S906，AMF的操作如下：AMF不处理；或者，当AMF确定已经将该UE的对应关系下发给AN时，AMF向AN发送应答消息，以向AN表明AMF已经下发了与S905中所述的会话信息所匹配的对应关系。
图10示出了本申请提供的再一种建立会话的信息交互图。以下图10和图11适用于UE同时通过聚合型的用户面模型和会话粒度的用户面模型访问DN的场景。例如，UE通过聚合隧道访问DN1，并且通过会话隧道访问DN2。其中，UE在聚合隧道上具有2个 会话。在会话隧道上具有1个会话。
当会话隧道上的下行数据先到达，聚合隧道上的下行数据后到达，就会执行图10的过程。如图10所示，该方法包括：
S1001a，UPF接收下行数据。
S1101b，UPF向SMF发送下行数据通知消息，该下行数据通知消息携带会话标识，以通知SMF触发该会话标识对应会话的连接恢复。
S1101c，SMF向AMF发送N11消息，携带会话上下文，该会话上下文包括会话标识对应的QoS参数、UPF隧道信息等。
S1002，当AMF判断UE处于空闲态时，AMF向AN发送寻呼消息。
此外，AMF通过除寻呼消息之外的消息向AN发送UE的对应关系，即，会话1、UE标识、SMF标识和会话1的会话信息的对应关系。
如果此时AMF接收到来自AN的通知消息或请求消息，如S1003所示，
S1004，按照方法300，AN会向AMF发送通知消息或请求消息，该通知消息或请求消息携带从会话1的下行数据中获取的UE IP地址和隧道标识信息(即，会话信息)。
S1005，AMF接收到通知消息或请求消息后，根据AMF保存的对应关系，判断AMF已经将对应关系发送给UE，或者已经寻呼UE，则AMF操作可以如下：不对接收到的通知消息或请求消息做任何处理；或者，AMF向AN发送应答消息以表示AMF已经将相应的对应关系下发给AN或者AMF已经寻呼UE。
图11示出了本申请提供的再一种建立会话的信息交互图。当聚合隧道上的下行数据先到达，会话隧道上的下行数据后到达，就会执行图11的过程。如图11所示，该方法包括：
S1101，AN从UPF接收会话1的下行数据，并从中获取到UE IP地址和隧道标识信息(即，会话信息)。此时，AN并不清楚该会话信息到底属于哪个会话，所述“会话1”可能是任意一个会话。
S1102，由于AN不知道会话信息属于哪个会话，按照方法300，AN向AMF发送通知消息或获取请求，该请求消息携带上述会话信息。
S1103，AMF接收到该通知消息或请求消息后，根据会话信息以及AMF保存的对应关系，确定会话信息对应的UE。并且，AMF将UE的对应关系发送给AN，和/或，AMF向AN发送寻呼消息。
如果此后，AMF收到来自SMF的N11消息，如S1104a-S1104c所示，
S1104a，UPF收到下行数据。
S1104b，UPF向SMF发送下行数据通知，携带会话标识。
S1104c，SMF向AMF发送N11消息，携带该会话标识对应的会话上下文，包括QoS参数、UPF隧道信息等。
AMF收到N11消息后，可以执行步骤S1105，或者，执行步骤S1106和S1107。
S1105，由于AMF已经将UE的对应关系发送给AN，和/或，AMF已经触发寻呼过程，则无须再次向AN发送对应关系，和/或，寻呼消息。因此，AMF的操作可以是：不做任何处理。S1106，AMF向AN发送寻呼消息。
AN接收到S1106所述寻呼消息之后的操作可以是：
S1107，不对上述寻呼消息做任何处理；或者，AN向AMF发送应答消息以表示AN已经寻呼UE。
上文详细介绍了本申请提供的建立会话的方法示例。可以理解的是，AN和AMF为了实现上述功能，其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，本申请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，但是这种实现不应认为超出本申请的范围。
本申请可以根据上述方法示例对AN等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，本申请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。
在采用集成的单元的情况下，图12示出了上述实施例中所涉及的AN的一种可能的结构示意图。AN1200包括：处理单元1202和通信单元1203。处理单元1202用于对AN1200的动作进行控制管理，例如，处理单元1202用于支持AN1200执行图3的S320和/或用于本文所描述的技术的其它过程。通信单元1203用于支持AN1200与其它网络实体的通信，例如与AMF之间的通信。AN1200还可以包括存储单元1201，用于存储AN1200的程序代码和数据。
其中，处理单元1202可以是处理器或控制器，例如可以是中央处理器(central processing unit，CPU)，通用处理器，数字信号处理器(digital signal processor，DSP)，专用集成电路(application-specific integrated circuit，ASIC)，现场可编程门阵列(field programmable gate array，FPGA)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。其可以实现或执行结合本申请公开内容所描述的各种示例性的逻辑方框，模块和电路。所述处理器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等。通信单元1203可以是通信接口。存储单元1201可以是存储器。
通信单元1203可用于执行下述操作：从UPF接收第一下行数据，该第一下行数据包括第一UE IP地址和第一隧道标识信息；向AMF发送第一消息，该第一消息包括第一UE IP地址和第一隧道标识信息；从AMF接收第二消息，该第二消息包括用于建立第一会话的上下文，该第一会话为与第一UE IP地址和第一隧道标识信息对应的会话。
AN1200通过向AMF发送第一UE IP地址和第一隧道标识信息，并接收AMF发送的用于恢复第一会话的上下文，从而可以恢复UE与AN之间与第一UE IP地址和第一隧道标识信息对应的无线连接，避免AN1200丢弃第一下行数据。
可选地，通信单元1203还用于：从AMF接收第三消息，该第三消息包括第一会话的标识、第一UE IP地址和第一隧道标识信息之间的第一对应关系，该第三消息还包括第二会话的标识、第二UE IP地址和第二隧道标识信息之间的第二对应关系。
当AN1200接收到第二会话对应的下行数据时，就可以根据所述第二对应关系确定下 行数据对应的会话，即第二会话，从而通过AMF从SMF获取到第二会话对应的会话上下文，从而可以恢复UE与AN1200之间与第二UE IP地址和第二隧道标识信息对应的无线连接，避免AN1200丢弃第二下行数据。
可选地，通信单元1203还用于：从UPF接收第二下行数据，所述第二下行数据包括所述第二UE IP地址和所述第二隧道标识信息；向AMF发送第二会话的标识；从AMF接收用于建立第二会话的上下文。
当AN1200接收到第二下行数据时，可以根据第二下行数据包括的第二UE IP地址和第二隧道标识信息确定第二会话的标识，并向AMF发送第二会话的标识，从而，AMF无需再根据第二UE IP地址和第二隧道标识信息确定第二会话的标识，可以直接将用于恢复第二会话的上下文发送给AN1200，提高了AMF的响应速度，减小了AMF的负担。
可选地，通信单元1203还用于：若第一UE处于空闲态，向第一UE发送寻呼消息，该第一UE为与第一UE IP地址和第一隧道标识信息对应的UE。
AN1200可以根据第一UE当前的具体情况选择相应的恢复第一会话的方法，例如当第一UE处于空闲态时，可以采取上述寻呼的方法恢复第一会话，从而可以避免AN1200丢弃第一下行数据；当第一UE处于连接态时，AN1200可以直接通过AMF向第一会话对应的SMF获取第一会话对应的会话上下文，从而恢复第一会话对应的AN1200与第一UE之间的空口连接，避免AN丢弃第一下行数据带来的用户体验降低。
可选地，第一隧道标识信息为隧道标识、AN侧的隧道信息和UPF侧的隧道信息中的至少一种。
可选地，通信单元1203还用于：通过第一会话向第一UE发送第一下行数据，第一UE为与第一UE IP地址和第一隧道标识信息对应的UE。
当处理单元1202为处理器，通信单元1203为通信接口，存储单元1201为存储器时，本申请所涉及的AN可以为图13所示的AN。
参阅图13所示，该AN1300包括：处理器1302、通信接口1303、存储器1301。其中，通信接口1303、处理器1302以及存储器1301可以通过内部连接通路相互通信，传递控制和/或数据信号。
所属领域的技术人员可以清楚地了解到，为了描述的方便和简洁，上述描述的装置和单元的具体工作过程，可以参考前述方法实施例中的对应过程，在此不加赘述。
在采用集成的单元的情况下，图14示出了上述实施例中所涉及的AMF的一种可能的结构示意图。AMF1400包括：处理单元1402和通信单元1403。处理单元1402用于对AMF1400的动作进行控制管理，例如，处理单元1402用于支持AMF1400执行图4的S410和/或用于本文所描述的技术的其它过程。通信单元1403用于支持AMF1400与其它网络实体的通信，例如与AN之间的通信。AMF1400还可以包括存储单元1401，用于存储AMF1400的程序代码和数据。
其中，处理单元1402可以是处理器或控制器，例如可以是CPU，通用处理器，DSP，ASIC，FPGA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。其可以实现或执行结合本申请公开内容所描述的各种示例性的逻辑方框，模块和电路。所述处理器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等。通信单元1403可以是通信接口等。存储单元1401可以是存储器。
通信单元1403用于执行下述操作：从AN接收第一消息，该第一消息包括第一UE IP地址和第一隧道标识信息；向AN发送第二消息，该第二消息包括用于建立第一会话的上下文，该第一会话为与第一UE IP地址和第一隧道标识信息对应的会话。
AMF1400从AN接收第一UE IP地址和第一隧道标识信息，并向AN发送用于恢复第一会话的上下文，从而可以恢复UE与AN之间与第一UE IP地址和第一隧道标识信息对应的无线连接，避免AN丢弃第一下行数据。
可选地，通信单元1403还用于：若第一UE处于空闲态，向该第一UE发送寻呼消息，第一UE为与第一UE IP地址和第一隧道标识信息对应的UE。
AMF1400可以根据第一UE当前的具体情况选择相应的恢复第一会话的方法，例如当第一UE处于空闲态时，可以采取上述寻呼的方法恢复第一会话，从而可以避免AN丢弃第一下行数据；当第一UE处于连接态时，AMF1400可以直接向第一会话对应的SMF获取第一会话对应的会话上下文发，并送给AN，从而使得AN恢复第一会话对应的AN与第一UE之间的空口连接，避免AN丢弃第一下行数据带来的用户体验降低。
可选地，通信单元1403还用于：向AN发送第三消息，该第三消息包括第一会话的标识、第一UE IP地址和第一隧道标识信息之间的第一对应关系，第三消息还包括第二会话的标识、第二UE IP地址和第二隧道标识信息之间的第二对应关系。
当AN接收到第二下行数据时，可以根据第二下行数据包括的第二UE IP地址和第二隧道标识信息确定第二会话的标识，并向AMF1400发送第二会话的标识，从而，AMF1400无需再根据第二UE IP地址和第二隧道标识信息确定第二会话的标识，可以直接将用于恢复第二会话的上下文发送给AN，提高了AMF1400的响应速度，减小了AMF1400的负担。
可选地，通信单元1403还用于：从AN接收第二会话的标识；向AN发送用于建立第二会话的上下文。
可选地，通信单元1403还用于：从SMF获取第一UE IP地址、第一隧道标识信息与第一会话的标识之间的第一对应关系。
可选地，第一隧道标识信息为隧道标识、AN侧的隧道信息和UPF侧的隧道信息中的至少一种。
当处理单元1402为处理器，通信单元1403为通信接口，存储单元1401为存储器时，本申请所涉及的AMF可以为图15所示的AMF。
参阅图15所示，该AMF1500包括：处理器1502、通信接口1503、存储器1501。其中，通信接口1503、处理器1502以及存储器1501可以通过内部连接通路相互通信，传递控制和/或数据信号。
所属领域的技术人员可以清楚地了解到，为了描述的方便和简洁，上述描述的装置和单元的具体工作过程，可以参考前述方法实施例中的对应过程，在此不加赘述。
装置和方法实施例中的AN或AMF完全对应，由相应的模块执行相应的步骤，例如通信单元执行方法实施例中发送和/或接收的步骤，除发送和/或接收外的其它步骤可以由处理模块或处理器执行。具体模块的功能可以参考相应的方法实施例，不再详述。
本申请还提供了一种通信芯片，其中存储有指令，当其在AN1200或AN1300上运行时，使得所述通信芯片执行上述各种实现方式中AN对应的方法。
本申请还提供了一种通信芯片，其中存储有指令，当其在AMF1400或AMF1500上 运行时，使得所述通信芯片执行上述各种实现方式中AMF对应的方法。
在本申请各个实施例中，各过程的序号的大小并不意味着执行顺序的先后，各过程的执行顺序应以其功能和内在逻辑确定，而不应对本申请的实施过程构成任何限定。
另外，本文中术语“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：单独存在A，同时存在A和B，单独存在B这三种情况。另外，本文中字符“/”，一般表示前后关联对象是一种“或”的关系。
结合本申请公开内容所描述的方法或者算法的步骤可以硬件的方式来实现，也可以是由处理器执行软件指令的方式来实现。软件指令可以由相应的软件模块组成，软件模块可以被存放于随机存取存储器(random access memory，RAM)、闪存、只读存储器(read only memory，ROM)、可擦除可编程只读存储器(erasable programmable ROM，EPROM)、电可擦可编程只读存储器(electrically EPROM，EEPROM)、寄存器、硬盘、移动硬盘、只读光盘(CD-ROM)或者本领域熟知的任何其它形式的存储介质中。一种示例性的存储介质耦合至处理器，从而使处理器能够从该存储介质读取信息，且可向该存储介质写入信息。当然，存储介质也可以是处理器的组成部分。处理器和存储介质可以位于ASIC中。另外，该ASIC可以位于AN或AMF中。当然，处理器和存储介质也可以作为分立组件存在于AN和AMF中。
在上述实施例中，可以全部或部分地通过软件、硬件、固件或者其任意组合来实现。当使用软件实现时，可以全部或部分地以计算机程序产品的形式实现。所述计算机程序产品包括一个或多个计算机指令。在计算机上加载和执行所述计算机程序指令时，全部或部分地产生按照本申请所述的流程或功能。所述计算机可以是通用计算机、专用计算机、计算机网络、或者其他可编程装置。所述计算机指令可以存储在计算机可读存储介质中，或者通过所述计算机可读存储介质进行传输。所述计算机指令可以从一个网站站点、计算机、服务器或数据中心通过有线(例如同轴电缆、光纤、数字用户线(digital subscriber line，DSL))或无线(例如红外、无线、微波等)方式向另一个网站站点、计算机、服务器或数据中心进行传输。所述计算机可读存储介质可以是计算机能够存取的任何可用介质或者是包含一个或多个可用介质集成的服务器、数据中心等数据存储设备。所述可用介质可以是磁性介质，(例如，软盘、硬盘、磁带)、光介质(例如，数字通用光盘(digital versatile disc，DVD)、或者半导体介质(例如固态硬盘(solid state disk，SSD))等。
以上所述的具体实施方式，对本申请的目的、技术方案和有益效果进行了进一步详细说明，所应理解的是，以上所述仅为本申请的具体实施方式而已，并不用于限定本申请的保护范围，凡在本申请的技术方案的基础之上，所做的任何修改、等同替换、改进等，均应包括在本申请的保护范围之内。

Claims (26)

  1. 一种建立会话的方法，其特征在于，所述方法包括：
    接入网AN设备从用户面功能UPF设备接收第一下行数据，所述第一下行数据包括第一用户设备UE网络协议IP地址和第一隧道标识信息；
    所述AN设备向接入和移动性管理功能AMF设备发送第一消息，所述第一消息包括所述第一UE IP地址和所述第一隧道标识信息；
    所述AN设备从所述AMF设备接收第二消息，所述第二消息包括用于建立第一会话的上下文，所述第一会话为与所述第一UE IP地址和所述第一隧道标识信息对应的会话。
  2. 根据权利要求1所述的方法，其特征在于，所述方法还包括：
    所述AN设备从所述AMF设备接收第三消息，所述第三消息包括所述第一会话的标识、所述第一UE IP地址和所述第一隧道标识信息之间的第一对应关系，所述第三消息还包括第二会话的标识、第二UE IP地址和第二隧道标识信息之间的第二对应关系。
  3. 根据权利要求2所述的方法，其特征在于，所述方法还包括：
    所述AN设备从所述UPF设备接收第二下行数据，所述第二下行数据包括所述第二UE IP地址和所述第二隧道标识信息；
    所述AN设备向所述AMF设备发送所述第二会话的标识；
    所述AN设备从所述AMF设备接收用于建立所述第二会话的上下文。
  4. 根据权利要求2或3所述的方法，其特征在于，所述方法还包括：
    若第一UE处于空闲态，所述AN设备向所述第一UE发送寻呼消息，所述第一UE为与所述第一UE IP地址和所述第一隧道标识信息对应的UE。
  5. 根据权利要求1至4中任一项所述的方法，其特征在于，所述第一隧道标识信息为隧道标识、AN设备侧的隧道信息和UPF设备侧的隧道信息中的至少一种。
  6. 根据权利要求1至5中任一项所述的方法，其特征在于，所述方法还包括：
    所述AN设备通过所述第一会话向第一UE发送所述第一下行数据，所述第一UE为与所述第一UE IP地址和所述第一隧道标识信息对应的UE。
  7. 一种建立会话的方法，其特征在于，所述方法包括：
    接入和移动性管理功能AMF设备从接入网AN设备接收第一消息，所述第一消息包括第一用户设备UE网络协议IP地址和第一隧道标识信息；
    所述AMF设备向所述AN设备发送第二消息，所述第二消息包括用于建立第一会话的上下文，所述第一会话为与所述第一UE IP地址和所述第一隧道标识信息对应的会话。
  8. 根据权利要求7所述的方法，其特征在于，所述方法还包括：
    若第一UE处于空闲态，所述AMF设备向所述第一UE发送寻呼消息，所述第一UE为与所述第一UE IP地址和所述第一隧道标识信息对应的UE。
  9. 根据权利要求7所述的方法，其特征在于，所述方法还包括：
    所述AMF设备向所述AN设备发送第三消息，所述第三消息包括所述第一会话的标识、所述第一UE IP地址和所述第一隧道标识信息之间的第一对应关系，所述第三消息还包括第二会话的标识、第二UE IP地址和第二隧道标识信息之间的第二对应关系。
  10. 根据权利要求9所述的方法，其特征在于，所述方法还包括：
    所述AMF设备从所述AN设备接收所述第二会话的标识；
    所述AMF设备向所述AN设备发送用于建立所述第二会话的上下文。
  11. 根据权利要求7至10中任一项所述的方法，其特征在于，所述方法还包括：
    所述AMF设备从会话管理功能SMF设备获取所述第一UE IP地址、所述第一隧道标识信息与所述第一会话的标识之间的第一对应关系。
  12. 根据权利要求7至11中任一项所述的方法，其特征在于，所述第一隧道标识信息为隧道标识、AN设备侧的隧道信息和UPF设备侧的隧道信息中的至少一种。
  13. 一种建立会话的装置，其特征在于，包括通信单元，所述通信单元用于：
    从用户面功能UPF设备接收第一下行数据，所述第一下行数据包括第一用户设备UE网络协议IP地址和第一隧道标识信息；
    向接入和移动性管理功能AMF设备发送第一消息，所述第一消息包括所述第一UE IP地址和所述第一隧道标识信息；
    从所述AMF设备接收第二消息，所述第二消息包括用于建立第一会话的上下文，所述第一会话为与所述第一UE IP地址和所述第一隧道标识信息对应的会话。
  14. 根据权利要求13所述的装置，其特征在于，所述通信单元还用于：
    从所述AMF设备接收第三消息，所述第三消息包括所述第一会话的标识、所述第一UE IP地址和所述第一隧道标识信息之间的第一对应关系，所述第三消息还包括第二会话的标识、第二UE IP地址和第二隧道标识信息之间的第二对应关系。
  15. 根据权利要求14所述的装置，其特征在于，所述通信单元还用于：
    从所述UPF设备接收第二下行数据，所述第二下行数据包括所述第二UE IP地址和所述第二隧道标识信息；
    向所述AMF设备发送所述第二会话的标识；
    从所述AMF设备接收用于建立所述第二会话的上下文。
  16. 根据权利要求14或15所述的装置，其特征在于，所述通信单元还用于：
    若第一UE处于空闲态，向所述第一UE发送寻呼消息，所述第一UE为与所述第一UE IP地址和所述第一隧道标识信息对应的UE。
  17. 根据权利要求13至16中任一项所述的装置，其特征在于，所述第一隧道标识信息为隧道标识、AN设备侧的隧道信息和UPF设备侧的隧道信息中的至少一种。
  18. 根据权利要求13至17中任一项所述的装置，其特征在于，所述通信单元还用于：
    通过所述第一会话向第一UE发送所述第一下行数据，所述第一UE为与所述第一UE IP地址和所述第一隧道标识信息对应的UE。
  19. 一种建立会话的装置，其特征在于，包括通信单元，所述通信单元用于：
    从接入网AN设备接收第一消息，所述第一消息包括第一用户设备UE网络协议IP地址和第一隧道标识信息；
    向所述AN设备发送第二消息，所述第二消息包括用于建立第一会话的上下文，所述第一会话为与所述第一UE IP地址和所述第一隧道标识信息对应的会话。
  20. 根据权利要求19所述的装置，其特征在于，所述通信单元还用于：
    若第一UE处于空闲态，向所述第一UE发送寻呼消息，所述第一UE为与所述第一 UE IP地址和所述第一隧道标识信息对应的UE。
  21. 根据权利要求19所述的装置，其特征在于，所述通信单元还用于：
    向所述AN设备发送第三消息，所述第三消息包括所述第一会话的标识、所述第一UE IP地址和所述第一隧道标识信息之间的第一对应关系，所述第三消息还包括第二会话的标识、第二UE IP地址和第二隧道标识信息之间的第二对应关系。
  22. 根据权利要求21所述的装置，其特征在于，所述通信单元还用于：
    从所述AN设备接收所述第二会话的标识；
    向所述AN设备发送用于建立所述第二会话的上下文。
  23. 根据权利要求19至22中任一项所述的装置，其特征在于，所述通信单元还用于：
    从会话管理功能SMF设备获取所述第一UE IP地址、所述第一隧道标识信息与所述第一会话的标识之间的第一对应关系。
  24. 根据权利要求19至23中任一项所述的装置，其特征在于，所述第一隧道标识信息为隧道标识、AN设备侧的隧道信息和UPF设备侧的隧道信息中的至少一种。
  25. 一种计算机可读存储介质，其特征在于，所述计算机可读存储介质存储有计算机程序，所述计算机程序使得通信设备执行权利要求1至12中任一项所述的方法。
  26. 一种包含指令的计算机程序产品，其特征在于，当所述计算机程序产品在计算机上运行时，使得计算机执行所述权利要求1至12中任一项所述的方法的步骤。
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