WO2019001381A1 - 会话管理的方法、装置、设备及系统 - Google Patents

会话管理的方法、装置、设备及系统 Download PDF

Info

Publication number
WO2019001381A1
WO2019001381A1 PCT/CN2018/092583 CN2018092583W WO2019001381A1 WO 2019001381 A1 WO2019001381 A1 WO 2019001381A1 CN 2018092583 W CN2018092583 W CN 2018092583W WO 2019001381 A1 WO2019001381 A1 WO 2019001381A1
Authority
WO
WIPO (PCT)
Prior art keywords
network element
session
session management
management network
information
Prior art date
Application number
PCT/CN2018/092583
Other languages
English (en)
French (fr)
Inventor
杨娇
唐廷芳
李岩
倪慧
Original Assignee
华为技术有限公司
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from CN201810235929.0A external-priority patent/CN109121170B/zh
Application filed by 华为技术有限公司 filed Critical 华为技术有限公司
Priority to EP21179391.4A priority Critical patent/EP3944665B1/en
Priority to BR112019027890-7A priority patent/BR112019027890A2/pt
Priority to EP18823163.3A priority patent/EP3637853B1/en
Publication of WO2019001381A1 publication Critical patent/WO2019001381A1/zh
Priority to US16/726,439 priority patent/US11071167B2/en
Priority to US17/354,106 priority patent/US11606839B2/en

Links

Images

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W36/00—Hand-off or reselection arrangements

Definitions

  • the present application relates to communication technologies, and in particular, to a method, device, device and system for session management.
  • the concept of the service area of the session management function (SMF) network element is proposed, that is, the SMF network element only manages the user plane function in the corresponding range (user Plane function, UPF) network element.
  • the corresponding packet data unit (PDU) session usually switches. Therefore, the corresponding UPF network element changes after the session is switched.
  • the switched UPF network element may no longer belong to the service area of the SMF network element corresponding to the UPF network element before the handover.
  • the session corresponds to the SMF network element 1 before the session is switched.
  • the two SMF network elements are corresponding to the SMF network element 1 and the SMF network element 2.
  • the embodiment of the present invention provides a method, a device, a device, and a system for session management, which are used to solve the problem of how to perform further session management in a scenario in which a session corresponds to two SMF network elements.
  • the application provides a method for session management, including:
  • the first session management network element allocates Internet Protocol IP information of the terminal device to the first session according to the session request message, where the first session is a branch of the established second session, or the a session is different from the established second session;
  • the first session management network element sends the IP information of the terminal device to the policy control function network element or the second session management network element, where the IP information is used for acquiring the policy information corresponding to the IP information.
  • the first session management network element receives a session request message sent by the second session management network element, and the first session management network element allocates a terminal for the first session according to the session request message.
  • the Internet Protocol IP information of the device the first session management network element sends the IP information of the terminal device to the policy control function network element or the second session management network element, where the IP information is used for the IP information corresponding to the IP information.
  • the acquisition of the policy information enables the first session management network element and the second session management network element to cooperate with each other to implement session management.
  • the method before the first session management network element sends the IP information of the terminal device to the policy control function network element, the method further includes:
  • the first session management network element sends the IP information of the terminal device to the network element of the policy control function, including:
  • the first session management network element sends the IP information of the terminal device to the policy control function network element according to the identifier of the policy control function network element.
  • the first session management network element acquires the identifier of the network element of the policy control function, including:
  • the first session management network element receives the identifier of the policy control function network element from the access and mobility management function network element.
  • the method further includes:
  • the first session management network element selects an anchor user plane function network element corresponding to the first session, and determines tunnel information of the anchor user plane function network element.
  • the method further includes:
  • the first session management network element selects a branch node user plane function network element corresponding to the first session, and determines tunnel information of the branch node user plane function network element.
  • the method further includes: the first session management network element sending the tunnel information of the anchor user plane function network element to the access and mobility management function network element.
  • the method further includes: sending, by the first session management network element, tunnel information of the user element function network element of the branch node to the access and mobility management function network element.
  • the method further includes: the first session management network element receiving a session context of the first session sent by the second session management network element;
  • the first session management network element sends the change indication information to the policy control function network element, where the change indication information is used to instruct the first session management network element to manage the first session.
  • the method further includes:
  • the first session management network element receives the release indication information sent by the second session management network element, where the release indication information is used to indicate that the first session is released;
  • the first session management network element releases the user plane resource of the first session and the IP information according to the release indication information.
  • the first session management network element is a session management network element that manages a user plane function network element directly connected to the access network network element
  • the second session management network element is a management anchor.
  • the session management network element of the user plane function network element is a session management network element that manages a user plane function network element directly connected to the access network network element
  • the first session management network element is configured to manage an anchor user plane function network element corresponding to the first session and a second network session corresponding to the terminal device, and an access network element a session management network element of the directly connected user plane function network element, where the second session management network element is a session management network element that manages an anchor user plane function network element corresponding to the second session, the first session and The second session is the same session or a different session.
  • the method further includes: the first session management network element sends the IP information by using a user to the terminal device.
  • the first session management network element before the sending, by the user, the IP information to the terminal device, the first session management network element further includes:
  • the first session management network element receives the sending indication information sent by the second session management network element, where the sending indication information is used to instruct the first session management network element to send the IP information to the terminal device.
  • the session request message includes at least one of the following: an identifier of the terminal device, an identifier of the first session, a data network name, a session, and a service continuity mode.
  • the application provides a method for session management, including:
  • the second session management network element determines to create a new session, the first session is a branch of the established second session, or the first session is a different session from the established second session;
  • the second session management network element sends a session request message to the first session management network element, where the session request message is used to request the first session management network element to allocate the Internet Protocol IP information of the terminal device to the first session. ;
  • the second session management network element acquires the policy information corresponding to the IP information from the policy control function network element according to the IP information.
  • the second session management network element sends a session request message to the first session management network element after determining to create the first session, where the session request message is used to request the first session management.
  • the network element allocates the Internet Protocol IP information of the terminal device to the first session, and implements the session management by the cooperation between the first session management network element and the second session management network element.
  • the method further includes:
  • the second session management network element receives the tunnel information of the user plane function network element of the first session sent by the first session management network element, where the user plane function network element is an anchor corresponding to the first session Point user plane function network element or branch node user plane function network element;
  • the second session management network element sends the tunnel information of the user plane function network element of the first session to the access and mobility management function network element.
  • the method further includes:
  • the second session management network element sends an identifier of the policy control function network element to the first session management network element.
  • the method further includes:
  • the second session management network element sends the change indication information to the access and mobility management function network element, where the change indication information is used to instruct the first session management network element to manage the first session.
  • the method further includes:
  • the second session management network element When it is determined that the first session needs to be released, the second session management network element sends release indication information to the first session management network element, where the release indication information is used to indicate that the first session is released.
  • the first session management network element is configured to manage an anchor user plane function network element corresponding to the first session and a second network session corresponding to the terminal device, and an access network element a session management network element of the directly connected user plane function network element, where the second session management network element is a session management network element that manages an anchor user plane function network element corresponding to the second session, the first session and The second session is the same session or a different session.
  • the first session management network element is a session management network element that manages a user plane function network element directly connected to the access network network element
  • the second session management network element is a management anchor.
  • the session management network element of the user plane function network element is a session management network element that manages a user plane function network element directly connected to the access network network element
  • the method further includes:
  • the second session management network element sends the sending indication information to the first session management network element, where the sending indication information is used to instruct the first session management network element to send the IP information to the terminal device.
  • the session request message includes at least one of the following: an identifier of the terminal device, an identifier of the first session, a data network name, a session, and a service continuity mode.
  • the application provides a device for session management, including:
  • a receiving module configured to receive a session request message sent by the second session management network element
  • a processing module configured to allocate Internet Protocol IP information of the terminal device to the first session according to the session request message, where the first session is a branch of the established second session, or the first session is The established second session is a different session;
  • a sending module configured to send the IP information of the terminal device to the policy control function network element or the second session management network element, where the IP information is used for acquiring the policy information corresponding to the IP information.
  • the receiving module is further configured to obtain an identifier of the network element of the policy control function
  • the sending module is specifically configured to send, according to the identifier of the policy control function network element, the IP information of the terminal device to the policy control function network element.
  • the receiving module acquires the identifier of the network element of the policy control function, and specifically includes:
  • the processing module is further configured to select an anchor user plane function network element corresponding to the first session, and determine tunnel information of the anchor user plane function network element.
  • the processing module is further configured to select a branch node user plane function network element corresponding to the first session, and determine tunnel information of the branch node user plane function network element.
  • the sending module is further configured to send, to the access and mobility management function network element, tunnel information of the anchor user plane function network element.
  • the sending module is further configured to send, to the access and mobility management function network element, tunnel information of the user element function network element of the branch node.
  • the receiving module is further configured to receive a session context of the first session sent by the second session management network element;
  • the sending module is further configured to send the change indication information to the policy control function network element, where the change indication information is used to instruct the first session management network element to manage the first session.
  • the receiving module is further configured to receive release indication information that is sent by the second session management network element, where the release indication information is used to indicate that the first session is released;
  • the processing module is further configured to release the user plane resource of the first session and the IP information according to the release indication information.
  • the first session management network element is configured to manage an anchor user plane function network element corresponding to the first session and a second network session corresponding to the terminal device, and an access network element a session management network element of the directly connected user plane function network element, where the second session management network element is a session management network element that manages an anchor user plane function network element corresponding to the second session, the first session and The second session is the same session or a different session.
  • the sending module is further configured to send the IP information by using a user to the terminal device.
  • the receiving module is further configured to receive sending indication information that is sent by the second session management network element, where the sending indication information is used to indicate that the first session management network element is located
  • the terminal device sends the IP information.
  • the session request message includes at least one of the following: an identifier of the terminal device, an identifier of the first session, a data network name, a session, and a service continuity mode.
  • the application provides a device for session management, including:
  • a processing module configured to determine to create a new session, where the first session is a branch of an established second session, or the first session is a different session from the established second session;
  • a sending module configured to send a session request message to the first session management network element, where the session request message is used to request the first session management network element to allocate Internet Protocol IP information of the terminal device to the first session.
  • the device further includes:
  • a receiving module configured to receive IP information of the terminal device sent by the first session management network element
  • the processing module is further configured to acquire, according to the IP information, policy information corresponding to the IP information from a policy control function network element.
  • the sending module is further configured to send, to the first session management network element, an identifier of a policy control function network element.
  • the receiving module is further configured to receive tunnel information of a user plane function network element of the first session sent by the first session management network element, where the user plane function network element An anchor user plane function network element or a branch node user plane function network element corresponding to the first session;
  • the sending module is further configured to send, to the access and mobility management function network element, tunnel information of the user plane function network element of the first session.
  • the sending module is further configured to send a session context of the first session to the first session management network element;
  • the sending module is further configured to send the change indication information to the access and mobility management function network element, where the change indication information is used to instruct the first session management network element to manage the first session.
  • the sending module is further configured to: when it is determined that the first session needs to be released, send release indication information to the first session management network element, where the release indication information is used to indicate Release the first session.
  • the first session management network element is configured to manage an anchor user plane function network element corresponding to the first session and a second network session corresponding to the terminal device, and an access network element a session management network element of the directly connected user plane function network element, where the second session management network element is a session management network element that manages an anchor user plane function network element corresponding to the second session, the first session and The second session is the same session or a different session.
  • the sending module is further configured to send, to the first session management network element, sending indication information, where the sending indication information is used to indicate that the first session management network element is to the The terminal device transmits the IP information.
  • the session request message includes at least one of the following: an identifier of the terminal device, an identifier of the first session, a data network name, a session, and a service continuity mode.
  • beneficial effects of the data transmitting apparatus provided by the fourth aspect and the possible implementation manners of the fourth aspect may be referred to the beneficial effects brought by the second aspect and the possible implementation manners of the second aspect. Let me repeat.
  • the application provides a network element, where the network element is a first session management network element, and the network element includes:
  • a receiver configured to receive a session request message sent by the second session management network element
  • a processor configured to allocate Internet Protocol IP information of the terminal device to the first session according to the session request message, where the first session is a branch of the established second session, or the first session is The established second session is a different session;
  • the sender is configured to send the IP information of the terminal device to the policy control function network element or the second session management network element, where the IP information is used for acquiring the policy information corresponding to the IP information.
  • the receiver is further configured to acquire an identifier of the network element of the policy control function
  • the transmitter is specifically configured to send, according to the identifier of the policy control function network element, the IP information of the terminal device to the policy control function network element.
  • the receiving, by the receiver, the identifier of the network element of the policy control function specifically includes:
  • the processor is further configured to select an anchor user plane function network element corresponding to the first session, and determine tunnel information of the anchor user plane function network element.
  • the processor is further configured to select a branch node user plane function network element corresponding to the first session, and determine tunnel information of the branch node user plane function network element.
  • the transmitter is further configured to send, to the access and mobility management function network element, tunnel information of the anchor user plane function network element.
  • the transmitter is further configured to send, to the access and mobility management function network element, tunnel information of the user interface function network element of the branch node.
  • the receiver is further configured to receive a session context of the first session sent by the second session management network element;
  • the transmitter is further configured to send the change indication information to the policy control function network element, where the change indication information is used to instruct the first session management network element to manage the first session.
  • the receiver is further configured to receive release indication information sent by the second session management network element, where the release indication information is used to indicate that the first session is released;
  • the processor is further configured to release the user plane resource of the first session and the IP information according to the release indication information.
  • the first session management network element is directly connected to the access network element corresponding to the anchor user plane function network element corresponding to the first session and the second session of the terminal device.
  • a session management network element of the connected user plane function network element where the second session management network element is a session management network element that manages an anchor user plane function network element corresponding to the second session, the first session and the The second session is the same session or a different session.
  • the transmitter is further configured to send the IP information by using a user to the terminal device.
  • the receiver is further configured to receive sending indication information that is sent by the second session management network element, where the sending indication information is used to indicate that the first session management network element is to the The terminal device transmits the IP information.
  • the session request message includes at least one of the following: an identification of the terminal device, an identification of the first session, a data network name, a session, and a business continuity mode.
  • the beneficial effects of the data transmitting apparatus provided by the fifth aspect and the possible implementation manners of the fifth aspect may be referred to the first aspect and the beneficial effects brought by the possible implementation manners of the first aspect. Let me repeat.
  • the application provides a network element, where the network element is a second session management network element, where the network element includes:
  • a processor configured to determine to create a new session, where the first session is a branch of an established second session, or the first session is a different session from the established second session;
  • a sender configured to send a session request message to the first session management network element, where the session request message is used to request the first session management network element to allocate Internet Protocol IP information of the terminal device to the first session.
  • the network element further includes:
  • a receiver configured to receive IP information of the terminal device sent by the first session management network element
  • the processor is further configured to acquire, according to the IP information, policy information corresponding to the IP information from a policy control function network element.
  • the transmitter is further configured to send, to the first session management network element, an identifier of a policy control function network element.
  • the receiver is further configured to receive tunnel information of a user plane function network element of the first session sent by the first session management network element, where the user plane function network element is An anchor user plane function network element or a branch node user plane function network element corresponding to the first session;
  • the transmitter is further configured to send, to the access and mobility management function network element, tunnel information of the user plane function network element of the first session.
  • the sender is further configured to send a session context of the first session to the first session management network element;
  • the transmitter is further configured to send the change indication information to the access and mobility management function network element, where the change indication information is used to instruct the first session management network element to manage the first session.
  • the processor is further configured to: when it is determined that the first session needs to be released, send, by the sender, release indication information to the first session management network element, where the release The indication information is used to indicate that the first session is released.
  • the first session management network element is configured to manage an anchor user plane function network element corresponding to the first session and a second network session corresponding to the terminal device, and an access network element a session management network element of the directly connected user plane function network element, where the second session management network element is a session management network element that manages an anchor user plane function network element corresponding to the second session, the first session and The second session is the same session or a different session.
  • the transmitter is further configured to send, to the first session management network element, sending indication information, where the sending indication information is used to indicate that the first session management network element is to the
  • the terminal device transmits the IP information.
  • the session request message includes at least one of the following: an identifier of the terminal device, an identifier of the first session, a data network name, a session, and a service continuity mode.
  • beneficial effects of the data transmitting apparatus provided by the sixth aspect and the possible embodiments of the sixth aspect may be referred to the beneficial effects of the second aspect and the possible implementation manners of the second aspect, and Let me repeat.
  • the embodiment of the present application provides a chip, including a processor, a transceiver component, and optionally, a memory, for performing at least one of the foregoing first aspect or the method of various embodiments of the first aspect.
  • Processing component or chip
  • the embodiment of the present application provides a chip, including a processor, a transceiver component, and optionally, a memory, for performing at least one of the foregoing second aspect or the method of the various embodiments of the second aspect.
  • Processing component or chip
  • the present application provides a readable storage medium, where an execution instruction is stored, where the first session management network element performs the foregoing when at least one processor of the first session management network element executes the execution instruction
  • a method of session management provided by the various embodiments of the first aspect or the first aspect.
  • the present application provides a readable storage medium, where an executable instruction is stored, and when at least one processor of the second session management network element executes the execution instruction, the second session management network element performs the foregoing
  • the second aspect provides a method of session management.
  • the application provides a program product, the program product comprising an execution instruction, the execution instruction being stored in a readable storage medium.
  • At least one processor of the first session management network element can read the execution instructions from a readable storage medium, the at least one processor executing the execution instructions such that the first session management network element implements the first aspect or various implementations of the first aspect The way the session management is provided.
  • the application provides a program product, the program product comprising an execution instruction, the execution instruction being stored in a readable storage medium.
  • At least one processor of the second session management network element can read the execution instructions from the readable storage medium, and the at least one processor executes the execution instructions such that the second session management network element implements the method of session management provided by the second aspect.
  • the present application provides a system for session management, including the device for session management according to the foregoing third aspect or the embodiments of the third aspect, and the manner of the fourth aspect or the fourth aspect.
  • the device for session management includes the device for session management according to the foregoing third aspect or the embodiments of the third aspect, and the manner of the fourth aspect or the fourth aspect.
  • FIG. 1 is a schematic diagram 1 of an application architecture of an embodiment of the present application.
  • FIG. 2 is a second schematic diagram of an application architecture of an embodiment of the present application.
  • FIG. 3 is a schematic diagram of a multi-homed PDU session scenario according to an embodiment of the present application.
  • FIG. 4 is a flowchart of a method for session management according to an embodiment of the present application.
  • FIG. 5A is a flowchart of a method for session management according to another embodiment of the present application.
  • FIG. 5B is a flowchart of an insertion process according to another embodiment of the present application.
  • FIG. 6 is a schematic diagram of a method for session management according to another embodiment of the present disclosure.
  • FIG. 7A is a flowchart of a method for session management according to another embodiment of the present application.
  • FIG. 7B is a flowchart of an insertion process according to another embodiment of the present application.
  • FIG. 8 is a schematic diagram of a method for session management according to another embodiment of the present disclosure.
  • FIG. 9 is a flowchart of a method for session management according to still another embodiment of the present application.
  • FIG. 10 is a schematic diagram of a method for session management according to another embodiment of the present disclosure.
  • FIG. 11 is a flowchart of a method for session management according to another embodiment of the present disclosure.
  • FIG. 12 is a schematic diagram of a method for session management according to another embodiment of the present disclosure.
  • FIG. 13 is a flowchart of a method for session management according to another embodiment of the present disclosure.
  • FIG. 14 is a schematic structural diagram of an apparatus for session management according to an embodiment of the present disclosure.
  • FIG. 15 is a schematic structural diagram of a session management network element according to an embodiment of the present disclosure.
  • SMS session management function
  • IP Internet protocol
  • SSC session and service continuity mode
  • User plane function (UPF) NE User plane function network element that performs user packet forwarding, statistics, and other processing functions, such as packet data network gateway (PDN-GW) and service The user plane function of the serving gateway (S-GW), the GW forwarding plane, the software defined network switch (SDN Switch), etc., wherein the branching point (BP) UPF sends the uplink data to different
  • the anchor user plane network element aggregates downlink data of different anchor user plane network elements.
  • Access and mobility management function (AMF) network element responsible for registration management, mobility management, lawful interception and other functions.
  • PCF Policy control function
  • access network (AN) network element also known as radio access network (RAN) network element, a device deployed in the radio access network to provide wireless communication functions for the terminal device .
  • the AN network element may include various forms of base stations, such as a macro base station, a micro base station (also referred to as a small station), a relay station, an access point, and the like.
  • the name of a device having a base station function may be different, for example, in a long term evalution (LTE) system, called an evolved node B (evolved node B, The eNB or eNodeB) is called a Node B or the like in a 3rd generation (3G) system.
  • LTE long term evalution
  • eNode B evolved node B
  • the eNB or eNodeB is called a Node B or the like in a 3rd generation (3G) system.
  • a terminal device is a device with wireless transceiver capability that can be deployed on land, indoors or outdoors, handheld or on-board; it can also be deployed on the water (such as ships); it can also be deployed in the air (such as airplanes, balloons, and Satellite, etc.).
  • the terminal may be a mobile phone, a tablet, a computer with wireless transceiver function, a virtual reality (VR) terminal, an augmented reality (AR) terminal, industrial control (industrial control) Wireless terminal, wireless terminal in self driving, wireless terminal in remote medical, wireless terminal in smart grid, wireless terminal in transport safety, A wireless terminal in a smart city, a wireless terminal in a smart home, and the like.
  • the embodiment of the present application can be applied to the following scenario: on the basis of the session management network element service area in the 5G, after the session of the terminal device is switched, the session corresponds to two SMF network elements, which are respectively the first session management network. Meta and second session management network elements. Specifically, when the terminal device establishes a session at the location 1, the session has a corresponding anchor user plane function network element, and the anchor user plane function network element is managed by the SMF1. The session switching occurs when the terminal moves from location 1 to location 2. After the session is switched, the user plane function network element directly connected to the network element of the access network corresponding to the session exceeds the SMF1 service area, but is managed by SMF2.
  • the session corresponds to two SMFs, that is, the first session management network element and the second session management network element may occur.
  • the embodiment of the present application is not limited to the scenario of session switching, and may be applicable to scenarios where other sessions correspond to two SMF network elements.
  • the first session management network element may be a session management network element that manages the first user plane function network element.
  • the first user plane function network element is a user plane function network element directly connected to the access network element corresponding to the switched session (for example, the second session), and may also be referred to as an intermediate session management function (intermediate SMF, I-SMF) network element.
  • the second session management network element may be a session management network element that manages an anchor user plane function network element corresponding to the switched session, and may also be referred to as an anchor session management function (anchor SMF, A-SMF) network element.
  • anchor SMF anchor SMF
  • A-SMF anchor session management function
  • the first session management network element is an I-SMF network element
  • the second session management network element is an A-SMF network element.
  • the application architecture of the embodiment of the present application may be as shown in FIG. 1 and FIG. 2 .
  • Figure 1 is a home-routed roaming like architecture.
  • the main difference between the architecture shown in Figure 1 and Figure 2 is that there is an interface between the I-SMF network element and the AMF network element in Figure 1, A.
  • the SMF network element communicates with the AMF network element through the I-SMF network element; in Figure 2, the A-SMF network element has an interface with the AMF network element, and the A-SMF network element can directly communicate with the AMF network element, without Through the I-SMF network element.
  • an interface may exist between the I-SMF and the PCF, and the interface between the I-SMF and the PCF is an N7 interface.
  • N4, N6, N9, N11, N16, and N16' are used to identify interfaces between different network elements.
  • the interface between the AMF network element and the I-SMF network element is N11 interface.
  • the embodiment of the present application mainly solves how to perform further session management in a scenario where the session of the terminal device corresponds to two SMFs, such as establishing a session (for example, a first session) or creating a new session branch (for example, a first session).
  • a session branch is established, specifically, a branch of the session after the handover is established, that is, the first session is a branch of the established second session, and it can be understood that the first session is the same session as the established second session (for example, : The first session has the same session ID as the second session).
  • the first session and the established second session are different sessions at this time (for example, the first session and the second session have different session IDs).
  • the established second session may specifically be a session established by the terminal device through the second session management network element.
  • a multi-homed PDU session is mainly applied in the IPv6.
  • the session management NE allocates an IP prefix to the terminal device.
  • a session in the scenario corresponds to multiple branches, and each branch corresponds to an anchor user plane function network element (ie, Anchor UPF1 and Anchor UPF2 in FIG. 3), access network element and branch node.
  • BP Branching Point
  • User plane function network element ie BP UPF in Figure 3
  • the access network element may be directly connected to the anchor user plane function network element, or may not be anchored.
  • the other user plane function network elements of the user plane function network element are directly connected, and the other user plane function network elements are further connected with the anchor user plane function network element.
  • N1, N2, N3, N4, N6, N9, and N11 are used to identify interfaces between different network elements.
  • FIG. 4 is a flowchart of a method for session management according to an embodiment of the present application. As shown in FIG. 4, the method in this embodiment may include:
  • Step 401 The second session management network element determines to create a new session.
  • the new session may be determined, where the first session is As a branch of the established second session, or the first session is a different session from the established second session.
  • Step 402 The second session management network element sends a session request message to the first session management network element.
  • the session request message is used to request the first session management network element to allocate Internet Protocol IP information of the terminal device to the first session.
  • the second session management network element determines that the first session needs to be established, sending the session request message to the first session management network element.
  • the second session management network element may determine that a first session needs to be established according to a message from another network element (for example, an AMF network element), or the second session management network element may also determine that the Establish a first session or establish a branch of the first session.
  • the first session may be a session, or a branch of a session, which is not limited herein.
  • the first session management network element is a session management network element that manages a user plane function network element directly connected to the access network network element
  • the second session management network element is a management anchor.
  • the session management network element of the user plane function network element is a session management network element that manages a user plane function network element directly connected to the access network network element
  • Step 403 The first session management network element allocates IP information of the terminal device to the first session according to the session request message.
  • the IP information may be an IP address or an IP prefix.
  • the first session management network element may allocate IP information of the terminal device to the first session according to the session request message, or may allocate IP information of the terminal device to the first session according to other information.
  • the first session management network element may perform other functions, such as selecting an anchor user plane function network element and/or a branch node user plane function network element, in addition to the function of allocating IP information.
  • the step 402 may further include: the first session management network element selects an anchor user plane function network element corresponding to the first session, and determines tunnel information of the anchor user plane function network element (for example, The IP address of the user plane network element and the identifier of the user plane network element; and/or the first session management network element selects the branch node user plane function network element corresponding to the first session, and determines the branch The node user plane functions the tunnel information of the network element.
  • the first session management network element selects an anchor user plane function network element corresponding to the first session, and determines tunnel information of the anchor user plane function network element (for example, The IP address of the user plane network element and the identifier of the user plane network element; and/or the first session management network element selects the branch node user plane function network element corresponding to the first session, and determines the branch The node user plane functions the tunnel information of the network element.
  • the first session management network element may also access and move when the first session management network element determines that the access network element needs to learn the tunnel information of the anchor user plane function network element.
  • the management function network element sends the tunnel information of the anchor user plane function network element. Further, the tunnel information of the anchor user plane function network element is sent by the access and mobility management function network element to the access network element.
  • the condition that the first session management network element determines that the access network element needs to know the tunnel information of the anchor user plane function network element may include: the anchor user plane function network element is the first session Corresponding user plane function network element directly connected to the access network element. When the foregoing conditions are not met, the first session management network element does not need to send the tunnel information of the anchor user plane function network element to the access and mobility management function network element.
  • the first session management network element may also perform access and mobility management.
  • the function network element sends the tunnel information of the user element function network element of the branch node. Further, the tunnel information of the branch node user plane function network element is sent by the access and mobility management function network element to the access network element.
  • the condition that the first session management network element determines that the access network element needs to know the tunnel information of the user interface function network element of the branch node may include: the branch node user plane function network element is the first session Corresponding user plane function network element directly connected to the network element of the access network, and the user plane function network element directly connected to the network element of the access network corresponding to the second session of the branch node is a different network yuan.
  • the first session management network element does not need to send the tunnel information of the user interface function network element of the branch node to the access and mobility management function network element.
  • the first session management network element sends a tunnel of the user plane function network element (which may be an anchor user plane function network element or a branch node user plane function network element) to the access and mobility management function network element.
  • the tunnel information of the user plane function network element may be directly sent by the first session management network element to the access and mobility management function network element, as shown in FIG. 2
  • the first session management network element sends the tunnel information of the user plane function network element to the second session management network element, and the second session management network element tunnels the user plane function network element Information is sent to the access and mobility management function network element.
  • Step 404 The first session management network element sends the IP information of the terminal device to the policy control function network element or the second session management network element.
  • the IP information is used for acquiring the policy information corresponding to the IP information.
  • the first session management network element may send the IP information to the policy control function network element through the N7 interface, so as to obtain the policy information corresponding to the IP information from the policy control function network element; or the first session management network element may The IP information is sent to the second session management network element through the N16 or N16' interface, so that the second session management network element obtains the policy information corresponding to the IP information from the policy control function network element according to the IP information.
  • the policy information corresponding to the IP information can be understood as the policy information generated by the policy control function network element according to the IP information.
  • the policy information corresponding to the IP information may include charging information, quality of service (QoS) parameter information, and routing rules.
  • the QoS parameter information may include a 5G QoS Identifier (5QI), an Allocation and Retention Priority (ARP), and a Session Aggregate Maximum Bit Rate (session-). At least one of AMBR).
  • the policy information corresponding to the IP information may be classified into policy information related to the terminal device, and/or policy information related to the user interface function network element of the branch node, and/or Policy information related to network access NEs.
  • the policy information related to the terminal device may include a routing rule.
  • the policy information related to the branch node user plane function network element may include at least one of charging information and session-AMBR.
  • the policy information related to the policy information related to the access network element may include at least one of session-AMBR, 5QI, and ARP.
  • the policy information related to the terminal device may be sent to the terminal device, where The policy information is sent to the second session management network element, and the policy information related to the access network element is sent to the access network element.
  • the first session management network element may obtain the identifier of the network element of the policy control function.
  • the first session management network element sends the IP information of the terminal device to the policy control function network element, which may include: the first session management network element controls the function network element according to the policy, The policy control function network element sends the IP information of the terminal device.
  • the first session management network element obtains the identifier of the policy control function network element, and includes: the first session management network element from the second session management network element or access and mobility management function The network element receives the identifier of the network element of the policy control function.
  • the method may further include the following step 405.
  • Step 405 The second session management network element acquires the policy information corresponding to the IP information from the policy control function network element according to the IP information.
  • step 404 For the specific description of the policy information corresponding to the IP information, refer to step 404, and details are not described herein again.
  • the foregoing session request message includes at least one of the following: an identifier of the terminal device, an identifier of the first session, a Data Network Name (DNN), a session, and a service continuity mode.
  • DNN Data Network Name
  • step 401-step 405 the second session management network element manages the first session, and the second session management network element part functions (for example, assigning a terminal device to the first session)
  • the IP information, the selection of the anchor user plane function network element, and the like) may also be completed by the first session management network element.
  • the method of this embodiment may further include: the second session management network element sends release indication information to the first session management network element, where the release indication information is used to indicate that the first session is released;
  • the first session management network element releases the user plane resource of the first session and the IP information according to the release indication information.
  • the user plane resource of the first session may include: a buffered data packet, a tunnel resource, a session context, and the like.
  • the second session management network element may further allocate management rights of the first session to the first session management network element, that is, the first session management network element manages the first session.
  • the embodiment may further include: the second session management network element sends the session context of the first session to the first session management network element, and/or information that interacts with the PCF network element (for example: The policy information, the interface information of the PCF, the IP address of the session, and the like); the second session management network element sends the change indication information to the access and mobility management function network element, where the change indication information is used to indicate the The first session management network element manages the first session. It can also be understood that the first session management network element sends the change indication information to the policy control function network element. After receiving the session context of the first session, the first session management network element may further save the session context of the first session in order to complete management of the first session.
  • the method of this embodiment may further include: when the first session management network element determines that the first session needs to be released, releasing the user plane resource of the first session and the IP information.
  • the method of this embodiment may further include: the first session management network element sending the IP information by the user to the terminal device.
  • the first session management network element may actively send the IP information to the terminal device, or the first session management network element may send the terminal information to the terminal according to the indication of the second session management network element.
  • the device sends the IP information.
  • the first session management network element may further include: sending, by the second session management network element, the sending indication information to the first session management network element
  • the sending indication information is used to indicate that the first session management network element sends the IP information to the terminal device; the first session management network element receives the sending sent by the second session management network element Instructions.
  • the session management method provided by the present application after the second session management network element determines that the first session is newly created, sends a session request message to the first session management network element, where the first session management network element is configured according to the session request message. And allocating the IP information of the terminal device to the first session and sending the IP information to the policy control function network element or the second session management network element, where the IP information is used for the policy information corresponding to the IP information. Acquiring, implementing the first session management network element and the second session management network element to cooperate with each other to implement session management.
  • FIG. 5 is a flowchart of a method for session management according to another embodiment of the present application
  • FIG. 6 is a schematic diagram of a method for session management according to another embodiment of the present application.
  • the first session management network element is an I-SMF network element
  • the second session management network element is an A-SMF network element.
  • the first session management network element selects an anchor user plane function network element and a branch node user plane function network element for the first session and allocates IP information of the terminal device for the first session.
  • the first session can be understood as a branch of the second session.
  • the method in this embodiment may include:
  • Step 501 The second session management network element determines that the anchor user plane function network element Anchor UPF1 of the second session is not excellent, and needs to select a new anchor point user plane function network element.
  • the terminal device establishes a session through the control plane path b1 at the position 1, and a1 in FIG. 6 represents the data path of the session.
  • session switching is completed through the control plane path b2
  • a2 in Fig. 6 represents the data path of the session after the handover (i.e., the second session).
  • the user plane function network element directly connected to the network element of the access network in the session switching process is not in the service area of the A-SMF, and the user plane function network element directly connected to the network element of the access network is managed by the I-SMF.
  • the second session management network element determines that the anchor user plane function network element Anchor UPF1 of the second session is not excellent, and needs to select a new anchor point user plane function network element.
  • the purpose of the second session management network element to select a new anchor user plane function network element is to establish a branch for the second session, for example, a first session.
  • the first session and the second session may exist at the same time, or only the first session may be established.
  • the second session management network element determines, according to at least one of the following information, that the anchor user plane function network element Anchor UPF1 of the second session is not superior: the location information of the terminal device, and the application function (application function) , AF) request, SMF load situation, the terminal device moves out of the service area of the Anchor UPF.
  • Step 502 The second session management network element sends a session request message to the first session management network element.
  • the second session management network element needs to be directly connected to the access network element corresponding to the first session that is not in the second session management network element service area.
  • the information of the first session management network element for example, the identity (ID) of the first session management network element, is stored in the second session management network element.
  • the second session management network element may send a session request message to the first session management network element according to the ID of the first session management network element.
  • the session request message is used to request to establish the first session, that is, the branch of the second session.
  • Step 503 The first session management network element selects an anchor user plane function Anchor UPF2 network element for the first session according to the session request message.
  • Step 504 The first session management network element sends an N4 Session Establishment Request (N4Session Establishment Request) message to the Anchor UPF2 network element, and receives an N4 Session Establishment Request/response message returned by the Anchor UPF2.
  • N4 Session Establishment Request N4Session Establishment Request
  • the tunnel information of the Anchor UPF2 network element may be allocated by the first session management network element or may also be allocated by the Anchor UPF2 network element.
  • the first session management network element may carry the tunnel information of the Anchor UPF2 network element in the N4 session establishment request message of this step.
  • the Anchor UPF2 network element may carry the tunnel information of the Anchor UPF2 network element in the N4 session establishment response message in this step.
  • the N4 session establishment request message may further include information such as packet detection, UPF execution, and reporting rules provided to the Anchor UPF2 network element.
  • Step 505 The first session management network element selects a branch node user plane function BP UPF network element for the first session according to the session request message.
  • Step 506 The first session management network element sends an N4 session establishment request message to the BP UPF network element, and receives an N4 session establishment response message returned by the BP UPF.
  • the tunnel information of the BP UPF network element may be allocated by the first session management network element or may also be allocated by the BP UPF network element.
  • the first session management network element may carry the tunnel information of the BP UPF network element in the N4 session establishment request message in this step.
  • the BP UPF network element may carry the tunnel information of the BP UPF network element in the N4 session establishment response message in this step.
  • the N4 session establishment request message further needs to carry the tunnel information of the Anchor UPF2 network element.
  • the N4 session establishment request message may further include information for providing a BP UPF network element with a transmission rule of uplink and downlink data and tunnel information of the (R)AN.
  • Step 507 The first session management network element allocates IP information of the terminal device to the first session according to the session request message.
  • step 507 there is no order limitation between step 507 and step 503-step 506.
  • the IP information of the terminal device may be allocated to the first session according to the Anchor UPF2 network element selected in step 503.
  • Step 508 The first session management network element sends a session response message to the second session management network element.
  • the session response message includes the IP information.
  • the session is selected.
  • the response message may also include tunnel information of the BP UPF network element.
  • the BP UPF network element selected in step 505 is the same network element as the user plane function network element directly connected to the (R) AN network element corresponding to the first session, the (R) AN network element is known.
  • the tunnel information of the user plane function network element directly connected to the (R) AN network element corresponding to the first session so the tunnel response information of the BP UPF network element is not required to be included in the session response message.
  • Step 509 The second session management network element acquires policy information corresponding to the IP information from the PCF network element according to the IP information.
  • the second session management network element sends the IP information to the PCF network element, and the PCF network element returns the policy information corresponding to the IP information to the first information according to the IP information.
  • Two session management network elements Two session management network elements.
  • Step 510 The second session management network element sends an N4 Session Modification Request (N4Session Modification Request) message to the Anchor UPF1 network element, and receives an N4 Session Modification Response (N4Session Modification Response) message returned by the Anchor UPF1.
  • N4Session Modification Request N4 Session Modification Request
  • N4Session Modification Response N4 Session Modification Response
  • the N4 session modification request message carries the tunnel information of the BP UPF network element, and the purpose is to notify the Anchor UPF1 network element of the tunnel information of the BP UPF network element. It should be noted that, when the tunnel response information of the BP UPF network element is included in the session response message, step 510 is performed; when the tunnel information of the BP UPF network element is not included in the session response message, step 510 is not performed.
  • Step 511 The first session management network element sends an N4 Session Modification Request (N4Session Modification Request) message to the Anchor UPF2 network element, and receives an N4 Session Modification Response (N4Session Modification Response) message returned by the Anchor UPF2.
  • N4 Session Modification Request N4Session Modification Request
  • N4Session Modification Response N4Session Modification Response
  • the N4 session modification request message carries the tunnel information of the BP UPF network element, and the purpose is to notify the Anchor UPF2 network element of the tunnel information of the BP UPF network element.
  • step 511 there is no sequence limitation between step 511, step 510, step 509 and step 506, and step 511 can be performed after step 506.
  • Step 512 The first session management network element sends an N11 message (N11message) to the AMF network element.
  • the N11 message carries the tunnel information of the BP UPF network element.
  • the step 512 is performed.
  • the user plane function network element directly connected to the (R)AN network element corresponding to the first session is the same network element, the (R)AN network element has already been used.
  • the tunnel information of the user plane function network element directly connected to the (R)AN network element corresponding to the first session is obtained, so step 512 is not required to be performed.
  • Step 513 The AMF network element sends an N2 Session Modification Request (N2Session Modification Request) message to the (R) AN network element according to the N11 message, and receives the N2 session modification returned by the (R) AN network element.
  • Response N2Session Modification Response
  • the N2 session modification request message carries the tunnel information of the BP UPF network element. It should be noted that step 513 is triggered by step 512, and step 513 is not performed when step 512 is not executed.
  • Step 514 The AMF returns a response (N11message Ack) of the N11 message to the first session management network element according to the N2 session modification response message.
  • Step 515 The first session management network element sends a route advertisement message to the terminal device by using an Anchor UPF2 network element.
  • the route carries the IP information in the message.
  • the first session management network element sends the IP information to the second session management network element, and the IP information is used by the second session management network element to obtain the policy information corresponding to the IP information.
  • the first session management network element sends a session response message including the IP information to the second session management network element, and in step 509, the second session management network element obtains the IP from the PCF network element according to the IP information.
  • the policy information corresponding to the information.
  • the first session management network element may send the IP information to the PCF network element, and the IP information is used by the first session management network element to obtain the policy information corresponding to the IP information.
  • step 509 in FIG. 5A is replaced by step 509'.
  • the session response message of step 508 may not include IP information.
  • Step 509 ′ the first session management network element acquires policy information corresponding to the IP information from the PCF network element according to the IP information.
  • step 509' may be followed by step 507, and there is no order limitation between step 509' and step 508.
  • the first session management network element may obtain the identifier of the PCF before the step 509 ′ of the new branch process as shown in FIG. 5A.
  • the second session management network element The session request message sent to the first session management network element may include the identifier of the PCF network element; or the first session management network element may be in the first session management network element as shown in FIG. 5B.
  • the identifier of the PCF network element is obtained in the insertion process.
  • the insertion process of the first session management network element may include the following steps:
  • Step 5a The second session management network element or the AMF network element selects the first session management network element.
  • the AMF network element may trigger the selection of the first session management network element by itself; or the second session management network element may trigger the AMF network element to select the first session.
  • the second session management network element is triggered by the second session management network element to select the first session management network element.
  • the AMF network element may determine, according to a location of the terminal device and a service area (SA) of the second session management network element, triggering selection of the session management network element, and selecting the first a session management network element; or the location of the second session management network element terminal device and the service area of the second session management network element, determining to trigger the selection of the session management network element, and sending a notification to the AMF network element a message, configured to notify the AMF network element to perform a session management network element, where the AMF network element selects the first session management network element; or the second session management network element may be based on a location of the terminal device
  • the service area of the second session management network element determines that the selection of the session management network element is triggered, and selects the first session management network element.
  • Step 5b The AMF network element sends an update session management context request to the first session management network element.
  • the update session management context request is used to trigger the first session management network element to select an I-UPF network element.
  • the I-UPF network element may be a user plane function network element directly connected to the (R)AN network element.
  • the update session management context request may further include an identifier of the PCF network element.
  • the AMF network element may obtain the identifier of the PCF network element by:
  • the AMF network element When the AMF network element triggers itself to select the first session management network element, if the PCF network element that interfaces with the AMF network element provides a policy of granularity of the terminal device, and the policy of the granularity of the terminal device and the policy of the session granularity The AMF network element may obtain the identifier of the PCF network element from the second session management network element before the AMF network element selects the first session management network element; if the terminal device granularity policy and session The AMF network element may not need to obtain the identifier of the PCF network element from the second session management network element. In addition, the AMF network element may obtain the identifier of the first session management network element after selecting the first session management network element, and therefore may send an update session management context request to the first session management network element.
  • the notification message sent by the second session management network element to the AMF network element may carry the PCF network.
  • the second session management network element may be after selecting the first session management network element. Sending the identifier of the first session management network element and the identifier of the PCF network element to the AMF network element.
  • the first session management network element may obtain the identifier of the PCF network element by using the following step 5c.
  • Step 5c The first session management network element acquires the identifier of the PCF network element from the second session management network element.
  • the first session management network element sends an identifier acquisition request to the second session management network element for requesting the identifier of the PCF network element, and further, the first session management network element And receiving an identifier obtaining response that is sent by the second session management network element and includes an identifier of the PCF network element.
  • step 5c may further include other steps in the first session management network element insertion process, such as the first session management network element inserting the I-UPF network element, establishing the (R)AN network element, and the Anchor UPF1 network element. User plane connection between I-UPF network elements.
  • the insertion process of the first session management network element may be before the new branch process shown in FIG. 5A.
  • the identifier of the PCF network element may be saved.
  • the terminal device moves to the location 2, the first session is established through the control plane path b3, that is, the branch of the second session, and a3 in FIG. 6 represents the data path of the branch of the established second session.
  • a2 is the data path of another branch of the second session.
  • the user plane function network element directly connected to the (R)AN network element corresponding to the second session is the same network element as the selected BP UPF network element, and is recorded as BP in the figure. UPF.
  • the method for session management is to send a session request message to the first session management network element by using the second session management network element, where the first session management network element selects an anchor point for the first session according to the session request message.
  • the user plane function network element, the branch node user plane function network element, and the IP information of the assigned terminal device implement a branch that establishes a session in a scenario where there are two session management network elements.
  • the newly established branch of the second session is still managed by the second session management network element, so the session information and peripheral interfaces on the second session management network element can be reused, such as reuse charging and policy.
  • the policy of the policy and charging control (PCC), the IP address of the PCF, etc. save the DN authorization process.
  • FIG. 7 is a flowchart of a method for session management according to another embodiment of the present disclosure
  • FIG. 8 is a schematic diagram of a method for session management according to another embodiment of the present disclosure.
  • the first session management network element is an I-SMF network element
  • the second session management network element is an A-SMF network element
  • the first session management network element selects an anchor for the first session.
  • the user plane function network element and the branch node user plane function network element are allocated and the IP information of the terminal device is allocated for the first session.
  • the first session can be understood as a branch of the second session.
  • the same content can be referred to the description of the embodiment of FIG. 5A and FIG. 6.
  • the method in this embodiment may include:
  • Step 701 The second session management network element determines that the anchor user plane function network element Anchor UPF1 of the second session is not excellent, and needs to select a new anchor point user plane function network element.
  • Step 702 The second session management network element sends a session request message to the first session management network element.
  • the session request message is used to request to establish the first session, that is, the branch of the second session.
  • Step 703 The first session management network element selects an anchor user plane function Anchor UPF2 network element for the first session according to the session request message.
  • Step 704 The first session management network element sends an N4 session establishment request message to the Anchor UPF2 network element, and receives an N4 session establishment response message returned by the Anchor UPF2.
  • Step 705 The first session management network element selects a branch node user plane function BP UPF network element for the first session according to the session request message.
  • Step 706 The first session management network element sends an N4 session establishment request message to the BP UPF network element, and receives an N4 session establishment response message returned by the BP UPF.
  • Step 707 The first session management network element allocates IP information of the terminal device to the first session according to the session request message.
  • Step 708 The first session management network element sends a session response message to the second session management network element.
  • Step 709 The second session management network element acquires the policy information corresponding to the IP from the PCF network element according to the IP information.
  • Step 710 The second session management network element sends an N4 session modification request message to the Anchor UPF1 network element, and receives an N4 session modification response message returned by the Anchor UPF1.
  • Step 711 The first session management network element sends an N4 session modification request message to the Anchor UPF2 network element, and receives an N4 session modification response message returned by the Anchor UPF2.
  • step 701-step 711 is similar to step 501-step 511, and details are not described herein again.
  • Step 712 The second session management network element sends an N11 message to the AMF network element.
  • the N11 message carries the tunnel information of the BP UPF network element.
  • the user plane function network element directly connected to the (R) AN network element corresponding to the first session is performed by step 712.
  • the (R)AN network element has already been used.
  • the tunnel information of the user plane function network element directly connected to the (R) AN network element corresponding to the first session is obtained, so step 712 is not required to be performed.
  • Step 713 The AMF network element sends an N2 session modification request message to the (R) AN network element according to the N11 message, and receives an N2 session modification response message returned by the (R) AN network element.
  • the N2 session modification request message carries the tunnel information of the BP UPF network element. It should be noted that step 713 is triggered by step 712, and step 713 is not performed when step 712 is not executed.
  • Step 714 The AMF returns a response of the N11 message to the second session management network element according to the N2 session modification response message.
  • Step 715 The second session management network element sends the sending indication information to the first session management network element.
  • the sending indication information is used to instruct the first session management network element to send the IP information to the terminal device.
  • Step 716 The first session management network element sends a route advertisement message to the terminal device by using an Anchor UPF2 network element.
  • the route carries the IP information in the message.
  • the first session management network element sends the IP information to the second session management network element, and the IP information is used by the second session management network element to obtain the policy information corresponding to the IP information.
  • the first session management network element sends a session response message including the IP information to the second session management network element, and in step 709, the second session management network element obtains the IP from the PCF network element according to the IP information.
  • the policy information corresponding to the information.
  • the first session management network element may send the IP information to the PCF network element, and the IP information is used by the first session management network element to obtain the policy information corresponding to the IP information.
  • step 709 in FIG. 5A is replaced by step 709'.
  • the session response message of step 708 may not include IP information.
  • Step 709' the first session management network element acquires policy information corresponding to the IP information from the PCF network element according to the IP information.
  • step 709' may be after step 707, and there is no order limitation between step 709' and step 708.
  • the first session management network element may obtain the identifier of the PCF before the step 709 ′ of the new branch process as shown in FIG. 7A.
  • the second session management network element The session request message sent to the first session management network element may include the identifier of the PCF network element; or the first session management network element may be in the first session management network element as shown in FIG. 7B.
  • the identifier of the PCF network element is obtained in the insertion process.
  • the insertion process of the first session management network element may include the following steps:
  • Step 7a The second session management network element or the AMF network element selects the first session management network element.
  • step 7a is similar to step 5a, and details are not described herein again.
  • Step 7b The AMF network element sends an update session management context request to the first session management network element by using the second session management network element.
  • step 7b the main difference between the step 7b and the step 5b is that the AMF network element needs to send the update session management context request to the first session management network element through the second session management network element in step 7b, and the other content is described in step 5b. No longer.
  • Step 7c The first session management network element acquires the identifier of the PCF network element from the second session management network element.
  • step 7c is similar to step 5c, and details are not described herein again.
  • the first session management network element may be further inserted into the flow, such as the first session management network element inserting the I-UPF network element, establishing the (R)AN network element, and the Anchor UPF1 network element. User plane connection between I-UPF network elements.
  • the insertion process of the first session management network element may be before the new branch process shown in FIG. 7A.
  • the identifier of the PCF network element may be saved.
  • the method for session management is to send a session request message to the first session management network element by using the second session management network element, where the first session management network element selects an anchor point for the first session according to the session request message.
  • the user plane function network element, the branch node user plane function network element, and the IP information of the assigned terminal device implement a branch that establishes a session in a scenario where there are two session management network elements.
  • the newly established branch of the second session is still managed by the second session management network element, so that the session information and the peripheral interfaces on the second session management network element can be reused, for example, the policy of reusing the PCC, The IP address of the PCF, etc., saves the DN authorization process.
  • the difference between the embodiment shown in FIG. 7A and FIG. 8 and the embodiment shown in FIG. 5A and FIG. 6 is mainly due to different architectures of the application.
  • the first session management network element has an interface with the access and mobility management function network element
  • the second session management network element accesses and moves before the session is switched.
  • the first session management network element has an interface with the access and mobility management function network element.
  • the second session management network element has an interface with the access and mobility management function network element. Therefore, in the embodiment shown in FIG. 5A and FIG.
  • the N11 message is sent by the first session management network element to the access and mobility management function network element, and in the embodiment shown in FIG. 7A and FIG.
  • the management network element sends an N11 message to the access and mobility management function network element.
  • the second session management network element needs to send the sending indication information to the first session management network element. After the first session management network element receives the sending indication information, it sends a route advertisement message carrying the IP information to the terminal device.
  • FIG. 9 is a flowchart of a method for session management according to another embodiment of the present disclosure
  • FIG. 10 is a schematic diagram of a method for session management according to another embodiment of the present disclosure.
  • the first session management network element is an I-SMF network element
  • the second session management network element is an A-SMF network element
  • the first session management network element is a first session selection anchor.
  • the user plane functions the network element and assigns the IP information of the terminal device to the first session.
  • the first session and the second session are different sessions.
  • the method in this embodiment may include:
  • Step 901 The second session management network element determines that the anchor user plane function network element Anchor UPF1 of the second session is not excellent, and needs to trigger the establishment of a new session.
  • the terminal device establishes a session through the control plane path B1 at the position 1, and A1 in FIG. 6 represents the data path of the session.
  • the session switching is completed through the control plane path B2, and A2 in Fig. 10 represents the data path (second session) of the session after the handover.
  • the second session management network element determines that the anchor user plane function network element Anchor UPF1 of the second session is not excellent, and needs to trigger the establishment of a new session.
  • the N3UPF network element in FIG. 10 indicates that the user plane function network element directly connected to the access network element is not in the service area of the second session management network element, and is configured by the first session management network.
  • the first session and the second session may exist at the same time, or only the first session may be established.
  • the second session management network element determines, according to at least one of the following information, that the anchor user plane function network element Anchor UPF1 of the second session is not superior: the location information of the terminal device, the request of the AF, the load condition of the SMF, and the terminal device moves out of the Anchor UPF. Service area.
  • Step 902 The second session management network element sends a non-access stratum (NAS) message to the terminal device by using the first session management network element and the AMF network element.
  • NAS non-access stratum
  • the NAS message may include the ID of the second session, and the NAS message is used by the second session management network element to notify the terminal device that the first session needs to be established.
  • the first session and the second session are sessions that connect to the same data network (DN). It should be noted that the first session management network element and the access and mobility management function network element may transparently transmit the NAS message.
  • Step 903 The terminal device sends a NAS message to the AMF network element.
  • the NAS message may include an ID of the first session, a DNN, a request type, and N1 session management information (SM information).
  • the NAS message is used to request to establish a first session.
  • the PDU session establishment request is included in the N1 session management information.
  • Step 904 The AMF network element sends a session management request (SM Request) message to the second session management network element by using the first session management network element.
  • SM Request session management request
  • the session management request message includes, in addition to the information contained in the NAS message in step 903, other related information, such as an AMF ID, a location information of the terminal device, and a user location information. Enter the technology type (Access Technology Type) and so on. It should be noted that the first session management network element may transparently transmit the session management request message.
  • the second session management network element needs to insert a user directly connected to the access network corresponding to the second session that is not in the second session management network element service area, in the process of performing the session switching in the second session.
  • the information of the first session management network element for example, the ID of the first session management network element, is saved in the second session management network element. Therefore, the second session management network element may send the session management request message to the first session management network element according to the ID of the first session management network element.
  • Step 905 The second session management network element sends a session request message to the first session management network element.
  • the second session management network element may send a session request message to the first session management network element according to the ID of the first session management network element.
  • the session request message is used to request to establish the first session.
  • Step 906 The first session management network element selects an anchor user plane function Anchor UPF2 network element for the first session according to the session request message.
  • Step 907 The first session management network element sends an N4 session establishment request message to the Anchor UPF2 network element, and receives an N4 session establishment response message returned by the Anchor UPF2.
  • the tunnel information of the Anchor UPF2 network element may be allocated by the first session management network element or may also be allocated by the Anchor UPF2 network element.
  • the first session management network element may carry the tunnel information of the Anchor UPF2 network element in the N4 session establishment request message.
  • the Anchor UPF2 network element may carry the tunnel information of the Anchor UPF2 network element in the N4 session establishment response message.
  • the N4 session establishment request message may further include information such as packet detection, UPF execution, and reporting rules provided to the Anchor UPF2 network element.
  • Step 908 The first session management network element allocates IP information of the terminal device to the first session according to the session request message according to the Anchor UPF2.
  • step 908 there is no limitation between the sequence of step 908 and step 906 and step 907.
  • the IP information of the terminal device may be allocated to the first session according to the Anchor UPF2 network element selected in step 906.
  • Step 909 The first session management network element sends a session response message to the second session management network element.
  • the session response message includes the IP information.
  • the session response message may further include tunnel information of the Anchor UPF2 network element (R) AN.
  • Step 910 The second session management network element obtains the policy information corresponding to the IP from the policy control function network element according to the IP information.
  • Step 911 The second session management network element sends a session management response (SM Response) message to the AMF network element by using the first session management network element.
  • SM Response session management response
  • the session management response message includes session management information (N2SM information) of the N2 interface and session management information (N1SM information) of the N1 interface.
  • the session response message in step 909 includes the tunnel information of the Anchor UPF2 network element, and the N2 interface in the session management response message sent by the second session management network element to the first session management network element.
  • the session management information includes the tunnel information of the Anchor UPF2 network element, and the session management information of the N1 interface in the session management response message sent by the second session management network element to the first session management network element is included in the session management information.
  • the IP information, the first session management network element transparently transmits a session management response message from the second session management network element to the access and mobility management function network element.
  • the session response message of step 909 does not include the tunnel information of the Anchor UPF2 network element, and the first session management network element needs the N2 interface of the session management response message from the second session management network element.
  • the tunnel information of the Anchor UPF2 network element is added to the session management information and sent to the access and mobility management function network element.
  • the session management information of the N1 interface further includes a PDU Session Establishment Accept message.
  • Step 912 The AMF network element sends an N2 PDU Session Request message to the access network ((R)AN) network element.
  • the N2 PDU session request message includes the NAS message and the session management information of the N2 interface obtained from step 911.
  • the NAS message includes the PDU session establishment accept message obtained from step 911 and the ID of the first session.
  • Step 913 The (R) AN network element allocates tunnel information of the (R) AN network element to the first session.
  • Step 914 The (R) AN network element interacts with the terminal device to establish a radio resource, and sends the NAS message included in the N2 PDU session request message received in step 912 to the terminal device.
  • Step 915 The (R) AN network element sends an N2 PDU Session Ack message to the AMF network element.
  • the PDU session response message of the N2 interface includes the tunnel information of the (R) AN network element allocated by the (R) AN network element in the first session in step 913.
  • Step 916 The AMF network element sends a session management request message to the first session management network element.
  • the session management request message includes tunnel information of the (R) AN network element.
  • Step 917 The first session management network element sends an N4 session modification request message to the Anchor UPF2 network element, and receives an N4 session modification response message returned by the Anchor UPF2.
  • the session modification request message of the N4 interface carries the tunnel information of the (R) AN network element, and the purpose is to notify the Anchor UPF2 network element of the tunnel information of the access network element.
  • Step 918 The first session management network element returns a session management response message to the access and mobility management function network element.
  • the session management response message is used as a response to the session management request message sent by the access and mobility management function network element in step 916.
  • step 917 there is no order limitation between step 917 and step 918.
  • the first session management network element sends the IP information to the second session management network element, and the IP information is used by the second session management network element to obtain the IP information.
  • the corresponding policy information is taken as an example.
  • the first session management network element sends a session response message including the IP information to the second session management network element, and in step 910, the second session management network element obtains the IP from the PCF network element according to the IP information.
  • the policy information corresponding to the information.
  • the first session management network element may send the IP information to the PCF network element, and the IP information is used by the first session management network element to obtain the policy information corresponding to the IP information.
  • step 910 in FIG. 9 is replaced by step 910'.
  • the session response message of step 909 may not include IP information.
  • Step 910' The first session management network element acquires policy information corresponding to the IP information from the PCF network element according to the IP information.
  • step 910' may be after step 908, and there is no order limitation between step 910' and step 908.
  • the first session management network element may obtain the identifier of the PCF before the step 910' of the new session flow shown in FIG. 9, for example, in step 905, the second session management network element
  • the session request message sent to the first session management network element may include the identifier of the PCF network element; or the first session management network element may be in the first session management network element as shown in FIG. 5B.
  • the identifier of the PCF network element is obtained in the insertion process.
  • the method for session management is to send a session request message to the first session management network element by using the second session management network element, where the first session management network element selects an anchor point for the first session according to the session request message.
  • the user plane function network element and the IP information of the terminal device are allocated to establish a session in a scenario where there are two session management network elements.
  • the newly created first session is still managed by the second session management network element, so the session information and the peripheral interfaces on the second session management network element can be reused, such as the policy of reusing the PCC and the IP of the PCF. Address, etc., saves the DN authorization process.
  • FIG. 11 is a flowchart of a method for session management according to another embodiment of the present disclosure
  • FIG. 12 is a schematic diagram of a method for session management according to another embodiment of the present disclosure.
  • the first session management network element is an I-SMF network element
  • the second session management network element is an A-SMF network element
  • the first session management network element selects an anchor for the first session.
  • the user plane functions the network element and assigns the IP information of the terminal device to the first session.
  • the first session and the second session are different sessions.
  • the same content can be referred to the description of the embodiment of FIG. 9 and FIG.
  • the method in this embodiment may include:
  • Step 1101 The second session management network element determines that the anchor user plane function network element Anchor UPF1 of the second session is not excellent, and needs to trigger the establishment of a new session.
  • step 1101 is similar to step 901, and details are not described herein again.
  • Step 1102 The second session management network element sends a Non-Access-Stratume (NAS) message to the terminal device by using the AMF network element.
  • NAS Non-Access-Stratume
  • the NAS message may include the ID of the second session, and the NAS message is used by the second session management network element to notify the terminal device that the first session needs to be established.
  • the first session and the second session are sessions connected to the same data network (DN). It should be noted that the access and mobility management function network element transparently transmits the NAS message.
  • Step 1103 The terminal device sends a NAS message to the AMF network element.
  • the NAS message may include an ID of the first session, a DNN, a request type, and N1 session management information (SM information).
  • the NAS message is used to request to establish a first session.
  • the PDU session establishment request is included in the N1 session management information.
  • Step 1104 The AMF network element sends a session management request (SM Request) message to the second session management network element.
  • SM Request session management request
  • the session management request message includes other related information, such as an AMF ID, a location information (User location information) of the terminal device, and access, in addition to the information included in the NAS message in step 1103.
  • Technology Type Access Technology Type
  • Step 1105 The second session management network element sends a session request message to the first session management network element.
  • Step 1106 The first session management network element selects an anchor user plane function Anchor UPF2 network element for the first session according to the session request message.
  • Step 1107 The first session management network element sends an N4 session establishment request message to the Anchor UPF2 network element, and receives an N4 session establishment response message returned by the Anchor UPF2.
  • Step 1108 The first session management network element allocates IP information of the terminal device to the first session according to the session request message according to the Anchor UPF2.
  • step 1105 - step 1108 is similar to step 905 - step 908, and details are not described herein again.
  • Step 1109 The first session management network element sends a session response message to the second session management network element.
  • the session response message includes the IP information and tunnel information of the Anchor UPF2 network element.
  • Step 1110 The second session management network element obtains the policy information corresponding to the IP from the policy control function network element according to the IP information.
  • Step 1111 The second session management network element sends a session management response (SM Response) message to the AMF network element.
  • SM Response session management response
  • the session management response message includes session management information (N2SM information) of the N2 interface and session management information (N1SM information) of the N1 interface.
  • the session management information of the N2 interface includes the tunnel information of the Anchor UPF2 network element, and the session management information of the N1 interface includes the IP information.
  • the session management information of the N1 interface further includes a PDU Session Establishment Accept message.
  • Step 1112 The AMF network element sends an N2 PDU Session Request message to the (R) AN network element.
  • Step 1113 The (R) AN network element allocates tunnel information of the (R) AN network element to the first session.
  • Step 1114 The (R) AN network element interacts with the terminal device, and sends the NAS message included in the N2 PDU session request message received in step 1112 to the terminal device.
  • Step 1115 The (R) AN network element sends an N2 PDU Session Ack message to the AMF network element.
  • step 1122 - step 1115 is similar to step 912 - step 915, and details are not described herein again.
  • Step 1116 The AMF network element sends a session management request message to the first session management network element by using the second session management network element.
  • the session management request message includes tunnel information of the (R) AN network element. It should be noted that the second session management network element may transparently transmit the session management request message.
  • Step 1117 The first session management network element sends an N4 session modification request message to the Anchor UPF2 network element, and receives an N4 session modification response message returned by the Anchor UPF2.
  • the N4 session modification request message carries the tunnel information of the (R) AN network element, and the purpose is to notify the Anchor UPF2 network element of the tunnel information of the (R) AN network element.
  • Step 1118 The first session management network element returns a session management response message to the AMF network element by using the second session management network element.
  • the session management response message is used as a response to the session management request message sent by the access and mobility management function network element in step 1116. It should be noted that the second session management network element may transparently transmit the session management response message.
  • the first session management network element sends the IP information to the second session management network element, and the IP information is used by the second session management network element to obtain the IP information.
  • the corresponding policy information is taken as an example.
  • the first session management network element sends a session response message including the IP information to the second session management network element, and in step 1110, the second session management network element obtains the IP from the PCF network element according to the IP information.
  • the policy information corresponding to the information.
  • the first session management network element may send the IP information to the PCF network element, and the IP information is used by the first session management network element to obtain the policy information corresponding to the IP information.
  • step 1110 in FIG. 11 is replaced with step 1110'.
  • the session response message of step 1109 may not include IP information.
  • Step 1110' the first session management network element acquires policy information corresponding to the IP information from the PCF network element according to the IP information.
  • step 1110' may be after step 1108, and there is no order limitation between step 1110' and step 1108.
  • the first session management network element may obtain the identifier of the PCF before the step 1110' of the new session flow shown in FIG. 11, for example, in step 1105, the second session management network element
  • the session request message sent to the first session management network element may include the identifier of the PCF network element; or the first session management network element may be in the first session management network element as shown in FIG. 7B.
  • the identifier of the PCF network element is obtained in the insertion process.
  • the method for session management is to send a session request message to the first session management network element by using the second session management network element, where the first session management network element selects an anchor point for the first session according to the session request message.
  • the user plane function network element and the IP information of the terminal device are allocated to establish a session in a scenario where there are two session management network elements.
  • the newly created first session is still managed by the second session management network element, so that the session information and the peripheral interfaces on the second session management network element can be reused, such as the policy of reusing the PCC and the IP address of the PCF. Etc., save the DN authorization process.
  • the difference between the embodiment shown in FIG. 11 and FIG. 12 and the embodiment shown in FIG. 9 and FIG. 10 is mainly due to the different architectures of the application.
  • the first session management network element has an interface with the access and mobility management function network element, and the second session management network element accesses and moves before the session is switched. There is an interface between the management function network elements. After the session is switched, the first session management network element has an interface with the access and mobility management function network element.
  • the second session management network element has an interface with the access and mobility management function network element. Therefore, in the embodiment shown in FIG. 9 and FIG.
  • the message between the second session management network element and the AMF network element needs to pass through the first session management network element, and in the embodiment shown in FIG. 11 and FIG.
  • the message between the session management network element and the AMF network element needs to pass through the second session management network element.
  • control plane paths in FIG. 6, FIG. 8, FIG. 10, and FIG. 12 do not pass through the user plane network element.
  • the first session management network element is fixed, and the second session management network element is changed according to the movement of the terminal device.
  • the method may further include: when the first session management network element determines that the first session needs to be released, releasing the user plane resource of the first session. And the IP information.
  • the first session management network element may determine to release the first session according to the release indication information sent by the second session management network element, where the release indication information is used to indicate release of the first session; or The first session management network element may determine to release the first session according to location information of the terminal device or the like.
  • FIG. 13 is a flowchart of a method for session management according to another embodiment of the present disclosure.
  • this embodiment mainly describes that the second session management network element is changed to the first.
  • the session management network element manages a specific implementation manner of the first session.
  • the method in this embodiment may include:
  • Step 1301 The second session management network element sends the session context of the first session to the first session management network element.
  • the session context of the first session may include: related information obtained by the second session management network element and the PCF network element, for example, policy information, interface information of the PCF, being the first session. IP information of the assigned terminal device, etc.
  • Step 1302 The second session management network element sends change indication information to the AMF network element.
  • the change indication information is used to instruct the first session management network element to manage the first session.
  • the second session management network element may send the change indication information to the AMF network element after the session context of the first session is migrated.
  • the AMF network element may respond back to the second session management network element.
  • Step 1303 The first session management network element sends the change indication information to a PCF network element.
  • step 1302 after receiving the change indication information, the PCF network element may also respond back to the first session management network element.
  • Step 1304 The first session management network element determines that the first session needs to be released.
  • the first session management network element determines that the first session needs to be released.
  • the terminal device, the PCF network element, or the first session management network element may trigger a release condition of the first session.
  • Step 1305 The first session management network element releases the user plane resource of the first session and the IP information of the terminal device allocated for the first session.
  • the session management network element that manages the first session is changed from the second session management network element to the related content of the first session management network element, and the first session management network element management After a session, the specific management mode, such as releasing the user plane resource of the first session and the IP information allocated for the first session, may be referred to the existing implementation manner, and details are not described herein again.
  • the session request message may be sent to other session management network elements, and other session management network elements may be used.
  • the functions of the first session management network element described above are completed.
  • the method for session management is to send a session context of a first session to a first session management network element by using a second session management network element, where the second session management network element sends an indication to the AMF network element to indicate the A session management network element manages the change indication information of the first session, and the first session management network element sends a change indication information session request message to the PCF network element, so that the session management network element managing the first session is managed by the second session management network.
  • the element is changed to the first session management network element, and the change of the session management network element for managing the first session in the scenario of having two session management network elements is implemented.
  • FIG. 14 is a schematic structural diagram of an apparatus for session management according to an embodiment of the present disclosure.
  • the apparatus provided in this embodiment may be implemented as part or all of the first session management network element by software, hardware or a combination of the two.
  • the apparatus may include: a receiving module 1401, configured to receive a session request message sent by a second session management network element; and a processing module 1402, configured to allocate a terminal device to the first session according to the session request message Internet Protocol IP information, wherein the first session is a branch of an established second session, or the first session is a different session from the established second session; and a sending module 1403 is configured to:
  • the policy control function network element sends the IP information of the terminal device to the second session management network element, where the IP information is used for acquiring the policy information corresponding to the IP information.
  • the receiving module 1401 is further configured to obtain an identifier of the network element of the policy control function.
  • the sending module 1403 is specifically configured to send the IP information of the terminal device to the network element of the policy control function according to the identifier of the policy control function network element.
  • the receiving module 1401 obtains the identifier of the network element of the policy control function, and specifically includes:
  • the processing module 1402 is further configured to select an anchor user plane function network element corresponding to the first session, and determine tunnel information of the anchor user plane function network element.
  • the processing module 1402 is further configured to select a branch node user plane function network element corresponding to the first session, and determine tunnel information of the branch node user plane function network element.
  • the sending module 1403 is further configured to send the tunnel information of the anchor user plane function network element to the access and mobility management function network element.
  • the sending module 1403 is further configured to send the tunnel information of the user element function network element of the branch node to the access and mobility management function network element.
  • the receiving module 1401 is further configured to receive the session context of the first session sent by the second session management network element
  • the sending module 1403 is further configured to send the change indication information to the policy control function network element.
  • the change indication information is used to instruct the first session management network element to manage the first session.
  • the receiving module 1401 is further configured to receive the release indication information that is sent by the second session management network element, where the release indication information is used to indicate that the first session is released, and the processing module 1402 is further configured to Declaring the release information, releasing the user plane resource of the first session and the IP information.
  • the first session management network element is configured to manage a user plane directly connected to the access network element corresponding to the anchor user plane function network element corresponding to the first session and the second session of the terminal device.
  • a session management network element of the function network element where the second session management network element is a session management network element that manages an anchor user plane function network element corresponding to the second session, the first session and the second session For the same session or different sessions.
  • the sending module 1403 is further configured to send the IP information by using a user to the terminal device.
  • the receiving module 1401 is further configured to receive the sending indication information that is sent by the second session management network element, where the sending indication information is used to instruct the first session management network element to send the IP information.
  • the session request message includes at least one of the following: an identifier of the terminal device, an identifier of the first session, a data network name, a session, and a service continuity mode.
  • the apparatus for session management provided in this embodiment may be used to implement the technical solution of the first session management network element side of any one of the foregoing method embodiments in the foregoing method embodiments, and the implementation principle and technology thereof. The effect is similar to the method embodiment, and details are not described herein again.
  • the present application may also provide a device for session management, which may be implemented as part or all of the second session management network element by software, hardware or a combination of both.
  • the apparatus provided in this embodiment is similar to the structure of the apparatus shown in FIG. 14, and may also include: a processing module and a sending module.
  • the processing module is configured to determine to create a new session, where the first session is a branch of the established second session, or the first session is a different session from the established second session; And a module, configured to send a session request message to the first session management network element, where the session request message is used to request the first session management network element to allocate Internet Protocol IP information of the terminal device to the first session.
  • the apparatus of this embodiment may further include: a receiving module, configured to receive IP information of the terminal device that is sent by the first session management network element; and the processing module is further configured to use the IP information according to the Obtaining, from the policy control function network element, the policy information corresponding to the IP information.
  • the sending module is further configured to send an identifier of the policy control function network element to the first session management network element.
  • the receiving module is further configured to receive tunnel information of the user plane function network element of the first session sent by the first session management network element, where the user plane function network element is the first The anchor user plane function network element or the branch node user plane function network element corresponding to the session;
  • the sending module is further configured to send, to the access and mobility management function network element, tunnel information of the user plane function network element of the first session.
  • the sending module is further configured to send a session context of the first session to the first session management network element, where the sending module is further configured to send a change to the access and mobility management function network element. Instructing information, the change indication information is used to instruct the first session management network element to manage the first session.
  • the sending module is further configured to: when it is determined that the first session needs to be released, send release indication information to the first session management network element, where the release indication information is used to indicate release of the first Conversation.
  • the first session management network element is configured to manage a user plane directly connected to the access network element corresponding to the anchor user plane function network element corresponding to the first session and the second session of the terminal device.
  • a session management network element of the function network element where the second session management network element is a session management network element that manages an anchor user plane function network element corresponding to the second session, the first session and the second session For the same session or different sessions.
  • the sending module is further configured to send the sending indication information to the first session management network element, where the sending indication information is used to instruct the first session management network element to send the IP information.
  • the session request message includes at least one of the following: an identifier of the terminal device, an identifier of the first session, a data network name, a session, and a service continuity mode.
  • the apparatus for session management provided in this embodiment may be used to implement the technical solution of the second session management network element side of any one of the foregoing method embodiments shown in FIG. The effect is similar to the method embodiment, and details are not described herein again.
  • FIG. 15 is a schematic structural diagram of a session management network element according to an embodiment of the present disclosure.
  • the session management network element may include a processor 1501, a memory 1502, a receiver 1503, a transmitter 1504, and at least one communication bus 1505.
  • Communication bus 1505 is used to implement a communication connection between components.
  • Memory 1502 may include high speed RAM memory, and may also include non-volatile memory NVM, such as at least one disk memory, in which various programs may be stored for performing various processing functions and implementing the method steps of the present embodiments.
  • the receiver 1503 in this embodiment may be a corresponding input interface having a communication function and a receiving information function, and may also be a radio frequency module or a baseband module on the first session management network element.
  • the transmitter 1504 in this embodiment may be a corresponding output interface having a communication function and a receiving information function, and may also be a radio frequency module or a baseband module on the first session management network element.
  • the receiver 1503 is configured to receive a session request message sent by the second session management network element.
  • the processor 1501 is configured to allocate, according to the session request message, Internet Protocol IP information of the terminal device for the first session, where the first session is a branch of the established second session, or the first session a different session from the established second session;
  • the sender 1504 is configured to send the IP information of the terminal device to the policy control function network element or the second session management network element, where the IP information is used for acquiring the policy information corresponding to the IP information.
  • the receiver 1503 is further configured to obtain an identifier of the network element of the policy control function.
  • the transmitter 1504 is configured to send, according to the identifier of the policy control function network element, the IP information of the terminal device to the policy control function network element.
  • the receiver 1503 obtains the identifier of the network element of the policy control function, and specifically includes:
  • the processor 1501 is further configured to select an anchor user plane function network element corresponding to the first session, and determine tunnel information of the anchor user plane function network element.
  • the processor 1501 is further configured to select a branch node user plane function network element corresponding to the first session, and determine tunnel information of the branch node user plane function network element.
  • the sender 1504 is further configured to send the tunnel information of the anchor user plane function network element to the access and mobility management function network element.
  • the transmitter 1504 is further configured to send the tunnel information of the user interface function network element of the branch node to the access and mobility management function network element.
  • the receiver 1503 is further configured to receive the session context of the first session sent by the second session management network element
  • the sender 1504 is further configured to send the change indication information to the policy control function network element.
  • the change indication information is used to instruct the first session management network element to manage the first session.
  • the receiver 1503 is further configured to receive the release indication information that is sent by the second session management network element, where the release indication information is used to indicate that the first session is released; the processor 1501 is further configured to Declaring the release information, releasing the user plane resource of the first session and the IP information.
  • the first session management network element is configured to manage a user plane directly connected to the access network element corresponding to the anchor user plane function network element corresponding to the first session and the second session of the terminal device.
  • a session management network element of the function network element where the second session management network element is a session management network element that manages an anchor user plane function network element corresponding to the second session, the first session and the second session For the same session or different sessions.
  • the sender 1504 is further configured to send the IP information by using a user to the terminal device.
  • the receiver 1503 is further configured to receive the sending indication information that is sent by the second session management network element, where the sending indication information is used to instruct the first session management network element to send the IP information.
  • the session request message includes at least one of the following: an identifier of the terminal device, an identifier of the first session, a data network name, a session, and a service continuity mode.
  • the session management network element provided in this embodiment may be used to implement the technical solution of the first session management network element side in any of the foregoing method embodiments in the foregoing method embodiments, and the implementation principle and technology thereof. The effect is similar to the method embodiment, and details are not described herein again.
  • the present application can also provide a session management network element, which is similar in structure to the session management network element shown in FIG.
  • the processor is configured to determine to create a new session, where the first session is a branch of the second session that is established, or the first session is a different session from the established second session; And sending a session request message to the first session management network element, where the session request message is used to request the first session management network element to allocate Internet Protocol IP information of the terminal device to the first session.
  • the receiver is configured to receive the IP information of the terminal device that is sent by the first session management network element
  • the processor is further configured to obtain, according to the IP information, a policy control function network element.
  • the policy information corresponding to the IP information.
  • the sender is further configured to send an identifier of the policy control function network element to the first session management network element.
  • the receiver is further configured to receive tunnel information of a user plane function network element of the first session sent by the first session management network element, where the user plane function network element is the first The anchor user plane function network element or the branch node user plane function network element corresponding to the session;
  • the transmitter is further configured to send, to the access and mobility management function network element, tunnel information of the user plane function network element of the first session.
  • the sender is further configured to send a session context of the first session to the first session management network element, where the sender is further configured to send a change to the access and mobility management function network element.
  • the change indication information is used to instruct the first session management network element to manage the first session.
  • the sender is further configured to: when it is determined that the first session needs to be released, send release indication information to the first session management network element, where the release indication information is used to indicate release of the first Conversation.
  • the first session management network element is configured to manage a user plane directly connected to the access network element corresponding to the anchor user plane function network element corresponding to the first session and the second session of the terminal device.
  • a session management network element of the function network element where the second session management network element is a session management network element that manages an anchor user plane function network element corresponding to the second session, the first session and the second session For the same session or different sessions.
  • the sender is further configured to send, to the first session management network element, the sending indication information, where the sending indication information is used to instruct the first session management network element to send the IP information.
  • the session request message includes at least one of the following: an identifier of the terminal device, an identifier of the first session, a data network name, a session, and a service continuity mode.
  • the session management network element provided in this embodiment may be used to implement the technical solution of the second session management network element side in any of the foregoing method embodiments in the foregoing method embodiments, and the implementation principle and technology thereof. The effect is similar to the method embodiment, and details are not described herein again.
  • the embodiment of the present application further provides a system for session management, including the device for session management provided by the foregoing embodiment.
  • the present application further provides a readable storage medium.
  • the readable storage medium stores instructions.
  • the first session management network element executes the instruction, the first session management network element performs the foregoing FIG. 4-13.
  • the method for session management of the first session management network element side provided by any one of the method embodiments is shown.
  • the present application further provides a readable storage medium.
  • the readable storage medium stores instructions.
  • the second session management network element executes the instruction, the second session management network element performs the foregoing FIG. 4-13.
  • the method for session management of the second session management network element side provided by any one of the method embodiments is shown.
  • the application also provides a program product comprising instructions stored in a readable storage medium.
  • At least one processor of the first session management network element can read the instruction from the readable storage medium and execute the instruction such that the first session management network element implements any of the method embodiments shown in FIG. 4 to FIG. The first session management method of the session management on the network element side provided by the embodiment.
  • the application also provides a program product comprising instructions stored in a readable storage medium.
  • At least one processor of the second session management network element can read the instruction from the readable storage medium and execute the instruction to cause the second session management network element to implement any of the method embodiments shown in FIG. 4 to FIG.
  • the second session management method of the session management on the network element side is provided by the embodiment.
  • the processor may be a central processing unit (English: Central Processing Unit, CPU for short), or may be other general-purpose processors, numbers.
  • Signal processor English: Digital Signal Processor, referred to as: DSP
  • ASIC Application Specific Integrated Circuit
  • the general purpose processor may be a microprocessor or the processor or any conventional processor or the like. The steps of the method disclosed in connection with the present application may be directly embodied by hardware processor execution or by a combination of hardware and software modules in a processor.
  • All or part of the steps of implementing the above method embodiments may be performed by hardware associated with the program instructions.
  • the aforementioned program can be stored in a readable memory.
  • the steps including the foregoing method embodiments are performed; and the foregoing memory (storage medium) includes: read-only memory (English: read-only memory, abbreviation: ROM), RAM, flash memory, hard disk, Solid state drive, magnetic tape (English: magnetic tape), floppy disk (English: floppy disk), optical disc (English: optical disc) and any combination thereof.

Landscapes

  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Mobile Radio Communication Systems (AREA)

Abstract

本申请实施例提供一种会话管理的方法、装置、设备及系统。该方法包括：第一会话管理网元接收第二会话管理网元发送的会话请求消息；所述第一会话管理网元根据所述会话请求消息，为第一会话分配终端设备的互联网协议IP信息，其中，所述第一会话为已建立的第二会话的分支，或者，所述第一会话与所述已建立的第二会话为不同的会话；所述第一会话管理网元向策略控制功能网元或所述第二会话管理网元发送所述终端设备的IP信息，所述IP信息用于所述IP信息对应的策略信息的获取。本申请实现了第一会话管理网元和第二会话管理网元相互配合实现会话管理。

Description

会话管理的方法、装置、设备及系统
本申请要求于2017年6月26日提交中国专利局、申请号为201710494938.7、申请名称为“会话管理的方法、装置、设备及系统”的中国专利申请，以及2018年3月21日提交中国专利局、申请号为201810235929.0、申请名称为“会话管理的方法、装置、设备及系统”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
本申请涉及通信技术，尤其涉及一种会话管理的方法、装置、设备及系统。
背景技术
在第五代(5rd generation，5G)移动通信技术中，提出了会话管理功能(session management function，SMF)网元的服务区域的概念，即SMF网元只管理对应范围内的用户面功能(user plane function，UPF)网元。当终端设备的位置发生变化时，对应的分组数据单元(packet data unit，PDU)会话通常会进行切换。因此，会出现该会话在进行切换后对应的UPF网元发生变更。然而，切换后的UPF网元可能不再属于切换前的UPF网元对应的SMF网元的服务区域。例如，该会话在进行会话切换前对应了SMF网元1，该会话进行切换之后对应了两个SMF网元，分别为SMF网元1和SMF网元2。
在会话切换后该会话对应两个SMF网元的场景下，如何进行进一步的会话管理成为目前亟待解决的问题。
发明内容
本申请实施例提供一种会话管理的方法、装置、设备及系统，用以解决会话对应两个SMF网元的场景下，如何进行进一步的会话管理的问题。
第一方面，本申请提供一种会话管理的方法，包括：
第一会话管理网元接收第二会话管理网元发送的会话请求消息；
所述第一会话管理网元根据所述会话请求消息，为第一会话分配终端设备的互联网协议IP信息，其中，所述第一会话为已建立的第二会话的分支，或者，所述第一会话与所述已建立的第二会话为不同的会话；
所述第一会话管理网元向策略控制功能网元或所述第二会话管理网元发送所述终端设备的IP信息，所述IP信息用于所述IP信息对应的策略信息的获取。
通过第一方面提供的数据传输方法，第一会话管理网元接收第二会话管理网元发送的会话请求消息，所述第一会话管理网元根据所述会话请求消息，为第一会话分配终端设备的互联网协议IP信息，所述第一会话管理网元向策略控制功能网元或所述第二会话管理网元发送所述终端设备的IP信息，所述IP信息用于所述IP信息对应的策略信息的获取，实现了第一会话管理网元和第二会话管理网元相互配合实现会话管理。
在一种可能实现的方式中，所述第一会话管理网元向策略控制功能网元发送所述 终端设备的IP信息之前，还包括：
所述第一会话管理网元获取所述策略控制功能网元的标识；
所述第一会话管理网元向策略控制功能网元发送所述终端设备的IP信息，包括：
所述第一会话管理网元根据所述策略控制功能网元的标识，向所述策略控制功能网元发送所述终端设备的IP信息。
在一种可能实现的方式中，所述第一会话管理网元获取所述策略控制功能网元的标识，包括：
所述第一会话管理网元从所述第二会话管理网元接收所述策略控制功能网元的标识；
或者，
所述第一会话管理网元从接入和移动管理功能网元接收所述策略控制功能网元的标识。
在一种可能实现的方式中，所述第一会话管理网元接收第二会话管理网元发送的会话请求消息之后，还包括：
所述第一会话管理网元选择所述第一会话对应的锚点用户面功能网元，并确定所述锚点用户面功能网元的隧道信息。
在一种可能实现的方式中，所述第一会话管理网元接收第二会话管理网元发送的会话请求消息之后，还包括：
所述第一会话管理网元选择所述第一会话对应的分支节点用户面功能网元，并确定所述分支节点用户面功能网元的隧道信息。
在一种可能实现的方式中，所述方法还包括：所述第一会话管理网元向接入和移动管理功能网元发送所述锚点用户面功能网元的隧道信息。
在一种可能实现的方式中，所述方法还包括：所述第一会话管理网元向接入和移动管理功能网元发送所述分支节点用户面功能网元的隧道信息。
在一种可能实现的方式中，所述方法还包括：所述第一会话管理网元接收所述第二会话管理网元发送的所述第一会话的会话上下文；
所述第一会话管理网元向策略控制功能网元发送变更指示信息，所述变更指示信息用于指示所述第一会话管理网元管理所述第一会话。
在一种可能实现的方式中，所述方法还包括：
所述第一会话管理网元接收所述第二会话管理网元发送的释放指示信息，所述释放指示信息用于指示释放所述第一会话；
所述第一会话管理网元根据所述释放指示信息，释放所述第一会话的用户面资源和所述IP信息。
在一种可能实现的方式中，所述第一会话管理网元为管理与接入网网元直接连接的用户面功能网元的会话管理网元，所述第二会话管理网元为管理锚点用户面功能网元的会话管理网元。
在一种可能实现的方式中，所述第一会话管理网元为管理所述第一会话对应的锚点用户面功能网元和所述终端设备的第二会话对应的与接入网网元直接连接的用户面功能网元的会话管理网元，所述第二会话管理网元为管理所述第二会话对应的锚点用 户面功能网元的会话管理网元，所述第一会话和所述第二会话为同一会话或不同会话。
在一种可能实现的方式中，所述方法还包括：所述第一会话管理网元通过用户面向所述终端设备发送所述IP信息。
在一种可能实现的方式中，所述第一会话管理网元通过用户面向所述终端设备发送所述IP信息之前，还包括：
所述第一会话管理网元接收所述第二会话管理网元发送的发送指示信息，所述发送指示信息用于指示所述第一会话管理网元向所述终端设备发送所述IP信息。
在一种可能实现的方式中，所述会话请求消息包括以下中的至少一种：所述终端设备的标识、所述第一会话的标识、数据网络名称、会话和业务连续性模式。
第二方面，本申请提供一种会话管理的方法，包括：
第二会话管理网元确定新建第一会话，所述第一会话为已建立的第二会话的分支，或者，所述第一会话与所述已建立的第二会话为不同的会话；
所述第二会话管理网元向第一会话管理网元发送会话请求消息，所述会话请求消息用于请求所述第一会话管理网元为所述第一会话分配终端设备的互联网协议IP信息；
所述第二会话管理网元接收所述第一会话管理网元发送的所述终端设备的IP信息；
所述第二会话管理网元根据所述IP信息，从策略控制功能网元获取所述IP信息对应的策略信息。
通过第二方面提供的数据传输方法，第二会话管理网元在确定新建第一会话后，向第一会话管理网元发送会话请求消息，所述会话请求消息用于请求所述第一会话管理网元为第一会话分配终端设备的互联网协议IP信息，实现了第一会话管理网元和第二会话管理网元相互配合实现会话管理。
在一种可能实现的方式中，所述方法还包括：
所述第二会话管理网元接收所述第一会话管理网元发送的所述第一会话的用户面功能网元的隧道信息，所述用户面功能网元为所述第一会话对应的锚点用户面功能网元或分支节点用户面功能网元；
所述第二会话管理网元向接入和移动管理功能网元发送所述第一会话的用户面功能网元的隧道信息。
在一种可能实现的方式中，所述方法还包括：
所述第二会话管理网元向所述第一会话管理网元发送策略控制功能网元的标识。
在一种可能实现的方式中，所述方法还包括：
所述第二会话管理网元向所述第一会话管理网元发送所述第一会话的会话上下文；
所述第二会话管理网元向接入和移动管理功能网元发送变更指示信息，所述变更指示信息用于指示所述第一会话管理网元管理所述第一会话。
在一种可能实现的方式中，所述方法还包括：
当确定需要释放所述第一会话时，所述第二会话管理网元向所述第一会话管理网元发送释放指示信息，所述释放指示信息用于指示释放所述第一会话。
在一种可能实现的方式中，所述第一会话管理网元为管理所述第一会话对应的锚 点用户面功能网元和所述终端设备的第二会话对应的与接入网网元直接连接的用户面功能网元的会话管理网元，所述第二会话管理网元为管理所述第二会话对应的锚点用户面功能网元的会话管理网元，所述第一会话和所述第二会话为同一会话或不同会话。
在一种可能实现的方式中，所述第一会话管理网元为管理与接入网网元直接连接的用户面功能网元的会话管理网元，所述第二会话管理网元为管理锚点用户面功能网元的会话管理网元。
在一种可能实现的方式中，所述方法还包括：
所述第二会话管理网元向所述第一会话管理网元发送发送指示信息，所述发送指示信息用于指示所述第一会话管理网元向所述终端设备发送所述IP信息。
在一种可能实现的方式中，所述会话请求消息包括下述中的至少一种：所述终端设备的标识、所述第一会话的标识、数据网络名称、会话和业务连续性模式。
第三方面，本申请提供一种会话管理的装置，包括：
接收模块，用于接收第二会话管理网元发送的会话请求消息；
处理模块，用于根据所述会话请求消息，为第一会话分配终端设备的互联网协议IP信息，其中，所述第一会话为已建立的第二会话的分支，或者，所述第一会话与所述已建立的第二会话为不同的会话；
发送模块，用于向策略控制功能网元或所述第二会话管理网元发送所述终端设备的IP信息，所述IP信息用于所述IP信息对应的策略信息的获取。
在一种可能实现的方式中，所述接收模块，还用于获取所述策略控制功能网元的标识；
所述发送模块，具体用于根据所述策略控制功能网元的标识，向所述策略控制功能网元发送所述终端设备的IP信息。
在一种可能实现的方式中，所述接收模块获取所述策略控制功能网元的标识，具体包括：
从所述第二会话管理网元接收所述策略控制功能网元的标识；
或者，
从接入和移动管理功能网元接收所述策略控制功能网元的标识。
在一种可能实现的方式中，所述处理模块，还用于选择所述第一会话对应的锚点用户面功能网元，并确定所述锚点用户面功能网元的隧道信息。
在一种可能实现的方式中，所述处理模块，还用于选择所述第一会话对应的分支节点用户面功能网元，并确定所述分支节点用户面功能网元的隧道信息。
在一种可能实现的方式中，所述发送模块，还用于向接入和移动管理功能网元发送所述锚点用户面功能网元的隧道信息。
在一种可能实现的方式中，所述发送模块，还用于向接入和移动管理功能网元发送所述分支节点用户面功能网元的隧道信息。
在一种可能实现的方式中，所述接收模块，还用于接收所述第二会话管理网元发送的所述第一会话的会话上下文；
所述发送模块，还用于向策略控制功能网元发送变更指示信息，所述变更指示信息用于指示所述第一会话管理网元管理所述第一会话。
在一种可能实现的方式中，所述接收模块，还用于接收所述第二会话管理网元发送的释放指示信息，所述释放指示信息用于指示释放所述第一会话；
所述处理模块，还用于根据所述释放指示信息，释放所述第一会话的用户面资源和所述IP信息。
在一种可能实现的方式中，所述第一会话管理网元为管理所述第一会话对应的锚点用户面功能网元和所述终端设备的第二会话对应的与接入网网元直接连接的用户面功能网元的会话管理网元，所述第二会话管理网元为管理所述第二会话对应的锚点用户面功能网元的会话管理网元，所述第一会话和所述第二会话为同一会话或不同会话。
在一种可能实现的方式中，所述发送模块，还用于通过用户面向所述终端设备发送所述IP信息。
在一种可能实现的方式中，所述接收模块，还用于接收所述第二会话管理网元发送的发送指示信息，所述发送指示信息用于指示所述第一会话管理网元向所述终端设备发送所述IP信息。
在一种可能实现的方式中，所述会话请求消息包括以下中的至少一种：所述终端设备的标识、所述第一会话的标识、数据网络名称、会话和业务连续性模式。
上述第三方面以及第三方面的各可能的实施方式所提供的数据发送装置，其有益效果可以参照上述第一方面以及第一方面的各可能的实施方式所带来的有益效果，在此不再赘述。
第四方面，本申请提供一种会话管理的装置，包括：
处理模块，用于确定新建第一会话，所述第一会话为已建立的第二会话的分支，或者，所述第一会话与所述已建立的第二会话为不同的会话；
发送模块，用于向第一会话管理网元发送会话请求消息，所述会话请求消息用于请求所述第一会话管理网元为所述第一会话分配终端设备的互联网协议IP信息。
在一种可能实现的方式中，所述装置还包括：
接收模块，用于接收所述第一会话管理网元发送的所述终端设备的IP信息；
所述处理模块，还用于根据所述IP信息，从策略控制功能网元获取所述IP信息对应的策略信息。
在一种可能实现的方式中，所述发送模块，还用于向所述第一会话管理网元发送策略控制功能网元的标识。
在一种可能实现的方式中，所述接收模块，还用于接收所述第一会话管理网元发送的所述第一会话的用户面功能网元的隧道信息，所述用户面功能网元为所述第一会话对应的锚点用户面功能网元或分支节点用户面功能网元；
所述发送模块，还用于向接入和移动管理功能网元发送所述第一会话的用户面功能网元的隧道信息。
在一种可能实现的方式中，所述发送模块，还用于向所述第一会话管理网元发送所述第一会话的会话上下文；
所述发送模块，还用于向接入和移动管理功能网元发送变更指示信息，所述变更指示信息用于指示所述第一会话管理网元管理所述第一会话。
在一种可能实现的方式中，所述发送模块，还用于当确定需要释放所述第一会话 时，向所述第一会话管理网元发送释放指示信息，所述释放指示信息用于指示释放所述第一会话。
在一种可能实现的方式中，所述第一会话管理网元为管理所述第一会话对应的锚点用户面功能网元和所述终端设备的第二会话对应的与接入网网元直接连接的用户面功能网元的会话管理网元，所述第二会话管理网元为管理所述第二会话对应的锚点用户面功能网元的会话管理网元，所述第一会话和所述第二会话为同一会话或不同会话。
在一种可能实现的方式中，所述发送模块，还用于向所述第一会话管理网元发送发送指示信息，所述发送指示信息用于指示所述第一会话管理网元向所述终端设备发送所述IP信息。
在一种可能实现的方式中，所述会话请求消息包括下述中的至少一种：所述终端设备的标识、所述第一会话的标识、数据网络名称、会话和业务连续性模式。
上述第四方面以及第四方面的各可能的实施方式所提供的数据发送装置，其有益效果可以参照上述第二方面以及第二方面的各可能的实施方式所带来的有益效果，在此不再赘述。
第五方面，本申请提供一种网元，所述网元为第一会话管理网元，所述网元包括：
接收器，用于接收第二会话管理网元发送的会话请求消息；
处理器，用于根据所述会话请求消息，为第一会话分配终端设备的互联网协议IP信息，其中，所述第一会话为已建立的第二会话的分支，或者，所述第一会话与所述已建立的第二会话为不同的会话；
发送器，用于向策略控制功能网元或所述第二会话管理网元发送所述终端设备的IP信息，所述IP信息用于所述IP信息对应的策略信息的获取。
在一种可能实现的方式中，所述接收器，还用于获取所述策略控制功能网元的标识；
所述发送器，具体用于根据所述策略控制功能网元的标识，向所述策略控制功能网元发送所述终端设备的IP信息。
在一种可能实现的方式中，所述接收器获取所述策略控制功能网元的标识，具体包括：
从所述第二会话管理网元接收所述策略控制功能网元的标识；
或者，
从接入和移动管理功能网元接收所述策略控制功能网元的标识。
在一种可能实现的方式中，所述处理器，还用于选择所述第一会话对应的锚点用户面功能网元，并确定所述锚点用户面功能网元的隧道信息。
在一种可能实现的方式中，所述处理器，还用于选择所述第一会话对应的分支节点用户面功能网元，并确定所述分支节点用户面功能网元的隧道信息。
在一种可能实现的方式中，所述发送器，还用于向接入和移动管理功能网元发送所述锚点用户面功能网元的隧道信息。
在一种可能实现的方式中，所述发送器，还用于向接入和移动管理功能网元发送所述分支节点用户面功能网元的隧道信息。
在一种可能实现的方式中所述接收器，还用于接收所述第二会话管理网元发送的 所述第一会话的会话上下文；
所述发送器，还用于向策略控制功能网元发送变更指示信息，所述变更指示信息用于指示所述第一会话管理网元管理所述第一会话。
在一种可能实现的方式中所述接收器，还用于接收所述第二会话管理网元发送的释放指示信息，所述释放指示信息用于指示释放所述第一会话；
所述处理器，还用于根据所述释放指示信息，释放所述第一会话的用户面资源和所述IP信息。
在一种可能实现的方式中所述第一会话管理网元为管理所述第一会话对应的锚点用户面功能网元和所述终端设备的第二会话对应的与接入网网元直接连接的用户面功能网元的会话管理网元，所述第二会话管理网元为管理所述第二会话对应的锚点用户面功能网元的会话管理网元，所述第一会话和所述第二会话为同一会话或不同会话。
在一种可能实现的方式中所述发送器，还用于通过用户面向所述终端设备发送所述IP信息。
在一种可能实现的方式中所述接收器，还用于接收所述第二会话管理网元发送的发送指示信息，所述发送指示信息用于指示所述第一会话管理网元向所述终端设备发送所述IP信息。
在一种可能实现的方式中所述会话请求消息包括以下中的至少一种：所述终端设备的标识、所述第一会话的标识、数据网络名称、会话和业务连续性模式。
上述第五方面以及第五方面的各可能的实施方式所提供的数据发送装置，其有益效果可以参照上述第一方面以及第一方面的各可能的实施方式所带来的有益效果，在此不再赘述。
第六方面，本申请提供一种网元，所述网元为第二会话管理网元，所述网元包括：
处理器，用于确定新建第一会话，所述第一会话为已建立的第二会话的分支，或者，所述第一会话与所述已建立的第二会话为不同的会话；
发送器，用于向第一会话管理网元发送会话请求消息，所述会话请求消息用于请求所述第一会话管理网元为所述第一会话分配终端设备的互联网协议IP信息。
在一种可能实现的方式中，所述网元还包括：
接收器，用于接收所述第一会话管理网元发送的所述终端设备的IP信息；
所述处理器，还用于根据所述IP信息，从策略控制功能网元获取所述IP信息对应的策略信息。
在一种可能实现的方式中，所述发送器，还用于向所述第一会话管理网元发送策略控制功能网元的标识。
在一种可能实现的方式中所述接收器，还用于接收所述第一会话管理网元发送的所述第一会话的用户面功能网元的隧道信息，所述用户面功能网元为所述第一会话对应的锚点用户面功能网元或分支节点用户面功能网元；
所述发送器，还用于向接入和移动管理功能网元发送所述第一会话的用户面功能网元的隧道信息。
在一种可能实现的方式中，所述发送器，还用于向所述第一会话管理网元发送所述第一会话的会话上下文；
所述发送器，还用于向接入和移动管理功能网元发送变更指示信息，所述变更指示信息用于指示所述第一会话管理网元管理所述第一会话。
在一种可能实现的方式中，所述处理器，还用于当确定需要释放所述第一会话时，通过所述发送器向所述第一会话管理网元发送释放指示信息，所述释放指示信息用于指示释放所述第一会话。
在一种可能实现的方式中，所述第一会话管理网元为管理所述第一会话对应的锚点用户面功能网元和所述终端设备的第二会话对应的与接入网网元直接连接的用户面功能网元的会话管理网元，所述第二会话管理网元为管理所述第二会话对应的锚点用户面功能网元的会话管理网元，所述第一会话和所述第二会话为同一会话或不同会话。
在一种可能实现的方式中，所述发送器，还用于向所述第一会话管理网元发送发送指示信息，所述发送指示信息用于指示所述第一会话管理网元向所述终端设备发送所述IP信息。
在一种可能实现的方式中，所述会话请求消息包括下述中的至少一种：所述终端设备的标识、所述第一会话的标识、数据网络名称、会话和业务连续性模式。
上述第六方面以及第六方面的各可能的实施方式所提供的数据发送装置，其有益效果可以参照上述第二方面以及第二方面的各可能的实施方式所带来的有益效果，在此不再赘述。
第七方面，本申请实施例提供了一种芯片，包括处理器、收发组件，可选地，还包括存储器，用于执行上述第一方面或者第一方面的各种实施方式的方法的至少一个处理元件(或芯片)。
第八方面，本申请实施例提供了一种芯片，包括处理器、收发组件，可选地，还包括存储器，用于执行上述第二方面或第二方面的各种实施方式的方法的至少一个处理元件(或芯片)。
第九方面，本申请提供一种可读存储介质，可读存储介质中存储有执行指令，当第一会话管理网元的至少一个处理器执行该执行指令时第一会话管理网元执行上述第一方面或者第一方面的各种实施方式提供的会话管理的方法。
第十方面，本申请提供一种可读存储介质，可读存储介质中存储有执行指令，当第二会话管理网元的至少一个处理器执行该执行指令时，第二会话管理网元执行上述第二方面提供的会话管理的方法。
第十一方面，本申请提供一种程序产品，该程序产品包括执行指令，该执行指令存储在可读存储介质中。第一会话管理网元的至少一个处理器可以从可读存储介质读取该执行指令，至少一个处理器执行该执行指令使得第一会话管理网元实施第一方面或者第一方面的各种实施方式提供的会话管理的方法。
第十二方面，本申请提供一种程序产品，该程序产品包括执行指令，该执行指令存储在可读存储介质中。第二会话管理网元的至少一个处理器可以从可读存储介质读取该执行指令，至少一个处理器执行该执行指令使得第二会话管理网元实施第二方面提供的会话管理的方法。
第十三方面，本申请提供一种会话管理的系统，包括上述第三方面或第三方面的各实施例方式所述的会话管理的装置，以及第四方面或第四方面的各实施例方式所述 的会话管理的装置。
附图说明
图1为本申请实施例应用架构的示意图一；
图2为本申请实施例应用架构的示意图二；
图3为本申请实施例多宿主PDU会话场景的示意图；
图4为本申请一实施例提供的会话管理的方法的流程图；
图5A为本申请另一实施例提供的会话管理的方法的流程图；
图5B为本申请另一实施例提供的插入流程的流程图；
图6为本申请另一实施例提供的会话管理的方法的示意图；
图7A为本申请又一实施例提供的会话管理的方法的流程图；
图7B为本申请又一实施例提供的插入流程的流程图；
图8为本申请又一实施例提供的会话管理的方法的示意图；
图9为本申请又一实施例提供的会话管理的方法的流程图；
图10为本申请又一实施例提供的会话管理的方法的示意图；
图11为本申请又一实施例提供的会话管理的方法的流程图；
图12为本申请又一实施例提供的会话管理的方法的示意图；
图13为本申请又一实施例提供的会话管理的方法的流程图；
图14为本申请一实施例提供的会话管理的装置的结构示意图；
图15为本申请一实施例提供的会话管理网元的结构示意图。
具体实施方式
对本申请涉及到的网元进行解释：
(1)会话管理功能(session management function，SMF)网元：进行会话管理，包括：会话建立，会话修改，会话释放，终端设备互联网协议(internet protocol，IP)地址或IP前缀分配和管理，UPF的选择和控制，确定会话的会话和业务连续性模式(session and service continuity mode，SSC mode)，合法监听等与会话相关的控制功能。
(2)用户面功能(user plane function，UPF)网元：完成用户报文的转发，统计等处理功能的用户面功能网元，如分组数据网关(packet data network gateway，PDN-GW)和服务网关(serving gateway，S-GW)的用户面功能、GW转发面、软件定义网络交换机(software defined network switch，SDN Switch)等,其中分支节点(branching point，BP)UPF将上行数据发送到不同的锚点用户面网元，聚合不同锚点用户面网元的下行数据。
(3)接入和移动管理功能(access and mobility management function，AMF)网元：负责注册管理，移动性管理，合法监听等功能。
(4)策略控制功能(policy control function，PCF)网元：提供策略规则，支持统一的策略架构管理网络行为等与策略相关的功能。
(5)接入网(access network，AN)网元：也称为无线接入网(radio access network， RAN)网元一种部署在无线接入网中用以为终端设备提供无线通信功能的装置。该AN网元可以包括各种形式的基站，例如：宏基站、微基站(也称为小站)、中继站、接入点等。在采用不同的无线接入技术的系统中，具备基站功能的设备的名称可能会有所不同，例如，在长期演进(long term evalution，LTE)系统中，称为演进的节点B(evolved nodeB，eNB或者eNodeB)，在第三代(3rd generation，3G)系统中，称为节点B(Node B)等。
终端设备是一种具有无线收发功能的设备，可以部署在陆地上，包括室内或室外、手持或车载；也可以部署在水面上(如轮船等)；还可以部署在空中(例如飞机、气球和卫星上等)。所述终端可以是手机(mobile phone)、平板电脑(pad)、带无线收发功能的电脑、虚拟现实(virtual reality，VR)终端、增强现实(augmented reality，AR)终端、工业控制(industrial control)中的无线终端、无人驾驶(self driving)中的无线终端、远程医疗(remote medical)中的无线终端、智能电网(smart grid)中的无线终端、运输安全(transportation safety)中的无线终端、智慧城市(smart city)中的无线终端、智慧家庭(smart home)中的无线终端等等。
本申请实施例可以应用在如下场景：在5G中提出会话管理网元服务区域的基础上，终端设备的会话进行会话切换后，该会话对应了两个SMF网元，分别为第一会话管理网元和第二会话管理网元。具体的，终端设备在位置1建立会话时，该会话有对应的锚点用户面功能网元，该锚点用户面功能网元由SMF1管理。当终端由位置1移动到位置2时发生会话切换，会话切换后该会话对应的与接入网网元直接连接的用户面功能网元超出了SMF1服务区域，而是由SMF2进行管理。此时，会出现会话对应了两个SMF，即第一会话管理网元和第二会话管理网元的场景。当然，本申请实施例也不一定限于会话切换的场景，还可适用于其他会话对应两个SMF网元的场景。
可选的，所述第一会话管理网元可以为管理第一用户面功能网元的会话管理网元。该第一用户面功能网元为切换后的会话(例如：第二会话)对应的与接入网网元直接连接的用户面功能网元，也可以被称为中间会话管理功能(intermediate SMF，I-SMF)网元。所述第二会话管理网元可以为管理切换后的会话对应的锚点用户面功能网元的会话管理网元，也可以被称为锚点会话管理功能(anchor SMF，A-SMF)网元；以所述第一会话管理网元为I-SMF网元，所述第二会话管理网元为A-SMF网元为例，本申请实施例的应用架构可以如图1和图2所示。图1是类似归属地漫游的架构(home-routed roaming like architecture)，图1与图2所示的架构主要的区别在于：图1中I-SMF网元与AMF网元之间有接口，A-SMF网元通过I-SMF网元与AMF网元进行通信；图2中A-SMF网元与AMF网元之间有接口，A-SMF网元可以直接与AMF网元进行通信，不需要通过I-SMF网元。可选的，I-SMF与PCF之间也可以存在接口，I-SMF与PCF之间的接口为N7接口。需要说明的是，图1和图2中N4、N6、N9、N11、N16、N16’用于标识不同网元之间的接口，例如，AMF网元与I-SMF网元之间的接口为N11接口。
本申请实施例主要解决在终端设备的会话对应两个SMF的场景下，如何进行进一步的会话管理，例如建立会话(例如：第一会话)或者新建会话分支(例如：第一会话)等。当建立会话分支时，具体是建立切换后的会话的分支，即第一会话是已建立的第 二会话的分支，此时可以理解为第一会话与已建立的第二会话为同一会话(例如：第一会话与第二会话具有相同的会话ID)。当建立会话时，此时第一会话与已建立的第二会话为不同会话(例如：第一会话与第二会话具有不同的会话ID)。这里，已建立的第二会话具体可以为终端设备通过第二会话管理网元建立的会话。
在本申请的实施例中，当建立会话的分支时，对应了多宿主PDU会话(multi-homed PDU session)场景，多宿主PDU会话主要应用在Ipv6中。在此场景下，会话管理网元为终端设备分配IP前缀。如图3所示，该场景中一个会话对应了多个分支，每一个分支都对应一个锚点用户面功能网元(即图3中Anchor UPF1和Anchor UPF2)，接入网网元与分支节点(BP，Branching Point)用户面功能网元(即图3中BP UPF)直接连接。需要说明的是，对于非多宿主PDU会话场景，即每一个会话对应一个锚点用户面功能网元，接入网网元可以与锚点用户面功能网元直接连接，或者也可以与不是锚点用户面功能网元的其他用户面功能网元直接连接，该其他用户面功能网元再与锚点用户面功能网元连接。需要说明的是，图3中N1、N2、N3、N4、N6、N9、N11用于标识不同网元之间的接口。
下面以具体地实施例对本申请的技术方案进行详细说明。下面这几个具体的实施例可以相互结合，对于相同或相似的概念或过程可能在某些实施例不再赘述。
图4为本申请一实施例提供的会话管理的方法的流程图。如图4所示，本实施例的方法可以包括：
步骤401、第二会话管理网元确定新建第一会话。
本步骤中，可选的，当所述第二会话管理网元确定已建立的第二会话的锚点用户面功能网元不优时，可以确定新建第一会话，其中，所述第一会话为已建立的第二会话的分支，或者，所述第一会话与所述已建立的第二会话为不同的会话。
步骤402、所述第二会话管理网元向第一会话管理网元发送会话请求消息。
本步骤中，所述会话请求消息用于请求所述第一会话管理网元为所述第一会话分配终端设备的互联网协议IP信息。当所述第二会话管理网元确定需要建立第一会话时，向所述第一会话管理网元发送该会话请求消息。可选的，所述第二会话管理网元可以根据来自其他网元(例如，AMF网元)的消息确定需要建立第一会话，或者所述第二会话管理网元也可以通过计算分析确定需要建立第一会话或建立第一会话的分支。具体的，第一会话可以是一个会话，或者一个会话的分支，在此不做限定。
在一种可能实现的方式中，所述第一会话管理网元为管理与接入网网元直接连接的用户面功能网元的会话管理网元，所述第二会话管理网元为管理锚点用户面功能网元的会话管理网元。
步骤403、所述第一会话管理网元根据所述会话请求消息，为所述第一会话分配终端设备的IP信息。
本步骤中，所述IP信息具体可以为IP地址或者IP前缀。所述第一会话管理网元可以根据所述会话请求消息，为第一会话分配终端设备的IP信息，或者也可以根据其他信息为所述第一会话分配终端设备的IP信息。
可选的，所述第一会话管理网元除了完成分配IP信息的功能之外，还可以完成其 他功能，例如选择锚点用户面功能网元和/或分支节点用户面功能网元等。
具体的，步骤402之后还可以包括：所述第一会话管理网元选择所述第一会话对应的锚点用户面功能网元，并确定所述锚点用户面功能网元的隧道信息(例如，用户面网元的IP地址和用户面网元的标识)；和/或，所述第一会话管理网元选择所述第一会话对应的分支节点用户面功能网元，并确定所述分支节点用户面功能网元的隧道信息。
可选的，在所述第一会话管理网元确定接入网网元需要获知所述锚点用户面功能网元的隧道信息时，所述第一会话管理网元还可以向接入和移动管理功能网元发送所述锚点用户面功能网元的隧道信息。进一步的，由所述接入和移动管理功能网元将所述锚点用户面功能网元的隧道信息发送至接入网网元。其中，所述第一会话管理网元确定接入网网元需要知道所述锚点用户面功能网元的隧道信息的条件可以包括：所述锚点用户面功能网元为所述第一会话对应的与接入网网元直接连接的用户面功能网元。当不满足上述条件时，第一会话管理网元不需要向接入和移动管理功能网元发送所述锚点用户面功能网元的隧道信息。
类似的，在所述第一会话管理网元确定接入网网元需要知道所述分支节点用户面功能网元的隧道信息时，所述第一会话管理网元还可以向接入和移动管理功能网元发送所述分支节点用户面功能网元的隧道信息。进一步的，由所述接入和移动管理功能网元将所述分支节点用户面功能网元的隧道信息发送至接入网网元。其中，所述第一会话管理网元确定接入网网元需要知道所述分支节点用户面功能网元的隧道信息的条件可以包括：所述分支节点用户面功能网元为所述第一会话对应的与接入网网元直接连接的用户面功能网元，且所述分支节点用户面功能网元与第二会话对应的与接入网网元直接连接的用户面功能网元为不同网元。当不满足上述条件时，第一会话管理网元不需要向接入和移动管理功能网元发送所述分支节点用户面功能网元的隧道信息。
其中，当所述第一会话管理网元向所述接入和移动管理功能网元发送用户面功能网元(具体可以为锚点用户面功能网元或分支节点用户面功能网元)的隧道信息时，对于图1所示的架构，可以由第一会话管理网元将所述用户面功能网元的隧道信息直接发送至所述接入和移动管理功能网元，对于图2所示的架构，第一会话管理网元将所述用户面功能网元的隧道信息发送至所述第二会话管理网元，再由所述第二会话管理网元将所述用户面功能网元的隧道信息发送至所述接入和移动管理功能网元。
步骤404、所述第一会话管理网元向策略控制功能网元或所述第二会话管理网元发送所述终端设备的IP信息。
本步骤中，所述IP信息用于所述IP信息对应的策略信息的获取。例如，所述第一会话管理网元可以通过N7接口向策略控制功能网元发送IP信息，以从策略控制功能网元获取IP信息对应的策略信息；或者，所述第一会话管理网元可以通过N16或N16’接口向所述第二会话管理网元发送IP信息，以用于所述第二会话管理网元根据IP信息从策略控制功能网元获取IP信息对应的策略信息。其中，IP信息对应的策略信息，可以理解为策略控制功能网元根据IP信息生成的策略信息。IP信息对应的策略信息可以包括计费信息、服务质量(Quality of Service，QoS)参数信息、路由规则(routing rule)。其中，QoS参数信息可以包括5G服务质量标识(5G QoS Identifier，5QI)、 分配和保留优先级(Allocation and Retention Priority，ARP)、会话粒度的聚合最大比特速率(per Session Aggregate Maximum Bit Rate，session-AMBR)中的至少一项。
可选的，所述IP信息对应的策略信息可以分为与所述终端设备相关的策略信息，和/或与所述分支节点用户面功能网元相关的策略信息，和/或与所述接入网网元相关的策略信息。例如，与所述终端设备相关的策略信息可以包括路由规则。与所述分支节点用户面功能网元相关的策略信息可以包括计费信息、session-AMBR中的至少一项。与所述接入网网元相关的策略信息相关的策略信息可以包括session-AMBR、5QI、ARP中的至少一项。
进一步可选的，在所述第一会话管理网元获取IP信息对应的策略信息后，可以将其中与终端设备相关的策略信息发送至终端设备，将其中与分支节点用户面功能网元相关的策略信息发送至第二会话管理网元，将其中与接入网网元相关的策略信息发送至接入网网元。
可选的，所述第一会话管理网元向策略控制功能网元发送所述终端设备的IP信息之前还可以包括：所述第一会话管理网元获取所述策略控制功能网元的标识。相应的，所述第一会话管理网元向策略控制功能网元发送所述终端设备的IP信息，具体可以包括：所述第一会话管理网元根据所述策略控制功能网元的标识，向所述策略控制功能网元发送所述终端设备的IP信息。
进一步可选的，所述第一会话管理网元获取所述策略控制功能网元的标识，包括：所述第一会话管理网元从所述第二会话管理网元或接入和移动管理功能网元接收所述策略控制功能网元的标识。
可选的，当所述第一会话管理网元将所述IP信息发送给所述第二会话管理网元时，还可以包括如下步骤405。
步骤405、所述第二会话管理网元根据所述IP信息，从策略控制功能网元获取所述IP信息对应的策略信息。
本步骤中，所述IP信息对应的策略信息的具体说明可以参见步骤404，在此不再赘述。
可选的，上述会话请求消息包括以下中的至少一种：所述终端设备的标识、所述第一会话的标识、数据网络名称(Data Network Name，DNN)、会话和业务连续性模式。
需要说明的是，在步骤401-步骤405中，所述第二会话管理网元管理所述第一会话，所述第二会话管理网元部分功能(例如：为所述第一会话分配终端设备的IP信息，选择锚点用户面功能网元等)还可以由所述第一会话管理网元完成。
可选的，本实施例的方法还可以包括：所述第二会话管理网元向所述第一会话管理网元发送释放指示信息，所述释放指示信息用于指示释放所述第一会话；所述第一会话管理网元根据所述释放指示信息，释放所述第一会话的用户面资源和所述IP信息。其中，所述第一会话的用户面资源可以包括：缓存的数据包，隧道资源，会话上下文等。
可选的，所述第二会话管理网元还可以将所述第一会话的管理权交给所述第一会话管理网元，即第一会话管理网元对所述第一会话进行管理。具体的，本实施例还可 以包括：所述第二会话管理网元向所述第一会话管理网元发送所述第一会话的会话上下文，和/或跟PCF网元交互的信息(比如：策略信息，PCF的接口信息，会话的IP地址等信息)；所述第二会话管理网元向所述接入和移动管理功能网元发送变更指示信息，所述变更指示信息用于指示所述第一会话管理网元管理所述第一会话。也可以理解为：所述第一会话管理网元向策略控制功能网元发送所述变更指示信息。所述第一会话管理网元在接收到所述第一会话的会话上下文之后，为了完成对所述第一会话的管理，还可以对所述第一会话的会话上下文进行保存。
本实施例的方法还可以包括：所述第一会话管理网元确定需要释放所述第一会话时，释放所述第一会话的用户面资源和所述IP信息。
可选的，对于多宿主PDU会话场景，需要将IP信息通过用户面发送至所述终端设备。因此，本实施例的方法还可以包括：所述第一会话管理网元通过用户面向所述终端设备发送所述IP信息。可选的，所述第一会话管理网元可以主动向所述终端设备发送所述IP信息，或者所述第一会话管理网元可以根据所述第二会话管理网元的指示向所述终端设备发送所述IP信息。可选的，所述第一会话管理网元通过用户面向所述终端设备发送所述IP信息之前还可以包括：所述第二会话管理网元向所述第一会话管理网元发送发送指示信息，所述发送指示信息用于指示所述第一会话管理网元向所述终端设备发送所述IP信息；所述第一会话管理网元接收所述第二会话管理网元发送的所述发送指示信息。
本申请提供的会话管理的方法，通过第二会话管理网元在确定新建第一会话后，向第一会话管理网元发送会话请求消息，所述第一会话管理网元根据所述会话请求消息，为第一会话分配终端设备的IP信息并将所述IP信息发送至策略控制功能网元或或所述第二会话管理网元，所述IP信息用于所述IP信息对应的策略信息的获取，实现了第一会话管理网元和第二会话管理网元相互配合实现会话管理。
图5A为本申请另一实施例提供的会话管理的方法的流程图，图6为本申请另一实施例提供的会话管理的方法的示意图。本实施例中以对于图1所示架构，第一会话管理网元为I-SMF网元，第二会话管理网元为A-SMF网元。第一会话管理网元为第一会话选择锚点用户面功能网元和分支节点用户面功能网元并为第一会话分配终端设备的IP信息。在本实施例中，第一会话可以理解成第二会话的分支。如图5A和图6所示，本实施例的方法可以包括：
步骤501、第二会话管理网元确定第二会话的锚点用户面功能网元Anchor UPF1不优，需要选择新的锚点用户面功能网元。
本步骤中，如图6所示，终端设备在位置1时通过控制面路径b1建立了会话，图6中a1表示会话的数据路径。当终端设备从位置1移动到位置2时，通过控制面路径b2完成了会话切换，图6中a2表示切换后会话的数据路径(即第二会话)。在会话的切换过程中与接入网网元直接连接的用户面功能网元不在A-SMF的服务区域里，由I-SMF管理该与接入网网元直接连接的用户面功能网元。此时，第二会话管理网元确定第二会话的锚点用户面功能网元Anchor UPF1不优，需要选择新的锚点用户面功能网元。其中，所述第二会话管理网元选择新的锚点用户面功能网元的目的是为所述第二会话建立分支，例如第一会话。第一会话和第二会话可以同时存在，也可以只建立 第一会话。在一种可能的实现方式中，第二会话管理网元根据如下信息的至少一种确定第二会话的锚点用户面功能网元Anchor UPF1不优：终端设备的位置信息、应用功能(application function，AF)的请求，SMF的负载情况，终端设备移出Anchor UPF的服务区域。
步骤502、所述第二会话管理网元向第一会话管理网元发送会话请求消息。
本步骤中，由于在会话切换的过程中，所述第二会话管理网元需要插入不在所述第二会话管理网元服务区域内的与所述第一会话对应的接入网网元直接连接的用户面网元，因此，所述第二会话管理网元中保存了所述第一会话管理网元的信息，例如，第一会话管理网元的标识(identity，ID)。所述第二会话管理网元可以根据所述第一会话管理网元的ID向所述第一会话管理网元发送会话请求消息。其中，所述会话请求消息用于请求建立所述第一会话，即所述第二会话的分支。
步骤503、所述第一会话管理网元根据所述会话请求消息，为所述第一会话选择锚点用户面功能Anchor UPF2网元。
步骤504、所述第一会话管理网元向所述Anchor UPF2网元发送N4会话建立请求(N4Session Establishment request)消息，并接收Anchor UPF2返回的N4会话建立响应(N4Session Establishment request/response)消息。
需要说明的是，所述Anchor UPF2网元的隧道信息可以由所述第一会话管理网元分配或者也可以由所述Anchor UPF2网元分配。当由第一会话管理网元分配时，所述第一会话管理网元可以在本步骤的N4会话建立请求消息中携带所述Anchor UPF2网元的隧道信息。当由所述Anchor UPF2网元分配时，所述Anchor UPF2网元可以在本步骤中的N4会话建立响应消息中携带所述Anchor UPF2网元的隧道信息。本步骤中，所述N4会话建立请求消息中还可以包括向Anchor UPF2网元提供的包检测，UPF执行，报告规则等信息。
步骤505、所述第一会话管理网元根据所述会话请求消息，为所述第一会话选择分支节点用户面功能BP UPF网元。
步骤506、所述第一会话管理网元向所述BP UPF网元发送N4会话建立请求消息，并接收BP UPF返回的N4会话建立响应消息。
需要说明的是，所述BP UPF网元的隧道信息可以由所述第一会话管理网元分配或者也可以由所述BP UPF网元分配。当由第一会话管理网元分配时，所述第一会话管理网元可以在本步骤中的N4会话建立请求消息中携带所述BP UPF网元的隧道信息。当由所述BP UPF网元分配时，所述BP UPF网元可以在本步骤中的N4会话建立响应消息中携带所述BP UPF网元的隧道信息。本步骤中，所述N4会话建立请求消息中还需要携带所述Anchor UPF2网元的隧道信息。所述N4会话建立请求消息中还可以包括向BP UPF网元提供上下行数据的传送规则和(R)AN的隧道信息等等信息。
步骤507、所述第一会话管理网元根据所述会话请求消息，为所述第一会话分配终端设备的IP信息。
需要说明的是，步骤507与步骤503-步骤506之间并没有先后顺序的限制。当步骤507在步骤503之后时，在步骤507中具体的可以根据步骤503中所选择的Anchor UPF2网元为所述第一会话分配终端设备的IP信息。
步骤508、所述第一会话管理网元向所述第二会话管理网元发送会话响应消息。
本步骤中，所述会话响应消息中包括所述IP信息。可选的，当步骤505中所选择的BP UPF网元与所述第一会话对应的与接入网(R)AN网元直接连接的用户面功能网元为不同网元时，所述会话响应消息中还可以包括BP UPF网元的隧道信息。当步骤505中所选择的BP UPF网元与所述第一会话对应的与(R)AN网元直接连接的用户面功能网元为同一网元时，由于(R)AN网元已获知了第一会话对应的与(R)AN网元直接连接的用户面功能网元的隧道信息，因此所述会话响应消息中不需要包括所述BP UPF网元的隧道信息。
步骤509、所述第二会话管理网元根据所述IP信息，从PCF网元获取所述IP信息对应的策略信息。
本步骤中，具体的，所述第二会话管理网元将所述IP信息发送至PCF网元，所述PCF网元根据所述IP信息将所述IP信息对应的策略信息返回给所述第二会话管理网元。
步骤510、所述第二会话管理网元向所述Anchor UPF1网元发送N4会话修改请求(N4Session Modification Request)消息，并接收Anchor UPF1返回的N4会话修改响应(N4Session Modification Response)消息。
本步骤中，所述N4会话修改请求消息中携带了所述BP UPF网元的隧道信息，目的是将所述BP UPF网元的隧道信息通知给Anchor UPF1网元。需要说明的是，当会话响应消息中包括所述BP UPF网元的隧道信息时，执行步骤510；当会话响应消息中未包括所述BP UPF网元的隧道信息时，不执行步骤510。
步骤511、所述第一会话管理网元向所述Anchor UPF2网元发送N4会话修改请求(N4Session Modification Request)消息，并接收Anchor UPF2返回的N4会话修改响应(N4Session Modification Response)消息。
本步骤中，所述N4会话修改请求消息中携带了所述BP UPF网元的隧道信息，目的是将所述BP UPF网元的隧道信息通知给Anchor UPF2网元。
需要说明的是，步骤511步骤510步骤509步骤506之间并没有先后顺序的限制，步骤511可以在步骤506之后执行。
步骤512、所述第一会话管理网元向AMF网元发送N11消息(N11message)。
本步骤中，所述N11消息中携带了所述BP UPF网元的隧道信息。需要说明的是，当步骤505中所选择的BP UPF网元与所述第一会话对应的与(R)AN网元直接连接的用户面功能网元为不同网元时，执行步骤512。当步骤505中所选择的BP UPF网元与所述第一会话对应的与(R)AN网元直接连接的用户面功能网元为同一网元时，由于所述(R)AN网元已经获知了与所述第一会话对应的与(R)AN网元直接连接的用户面功能网元的隧道信息，因此不需要执行步骤512。
步骤513、所述AMF网元根据所述N11消息，向所述(R)AN网元发送N2会话修改请求(N2Session Modification Request)消息，并接收所述(R)AN网元返回的N2会话修改响应(N2Session Modification Response)消息。
本步骤中，所述N2会话修改请求消息中携带所述BP UPF网元的隧道信息。需要说明的是，步骤513由步骤512触发，当不执行步骤512时也不执行步骤513。
步骤514、所述AMF根据所述N2会话修改响应消息，向所述第一会话管理网元返回所述N11消息的响应(N11message Ack)。
步骤515、所述第一会话管理网元通过Anchor UPF2网元向终端设备发送路由通告(router advertisement)消息。
本步骤中，所述路由通过消息中携带了所述IP信息。
需要说明的是，在本实施例的上述描述中，以第一会话管理网元将IP信息发送给第二会话管理网元，IP信息用于第二会话管理网元获取IP信息对应的策略信息为例。具体的，在步骤508中，第一会话管理网元向第二会话管理网元发送包括IP信息的会话响应消息，在步骤509中，第二会话管理网元根据IP信息从PCF网元获取IP信息对应的策略信息。
可替换地，第一会话管理网元可以将IP信息发送给PCF网元，IP信息用于第一会话管理网元获取IP信息对应的策略信息。具体的，图5A中步骤509替换为步骤509’，相应的，步骤508的会话响应消息中可以不包括IP信息。
步骤509’、所述第一会话管理网元根据所述IP信息，从PCF网元获取所述IP信息对应的策略信息。
本步骤中，需要说明的是，步骤509’可以在步骤507之后，步骤509’与步骤508之间并没有先后顺序的限制。进一步可选的，所述第一会话管理网元可以在如图5A所示的新建分支流程的步骤509’之前获取所述PCF的标识，例如在步骤502中，所述第二会话管理网元向所述第一会话管理网元发送的会话请求消息中可以包括所述PCF网元的标识；或者，所述第一会话管理网元可以在如图5B所示的第一会话管理网元的插入流程中获得PCF网元的标识。
如图5B所示，所述第一会话管理网元的插入流程可以包括如下步骤：
步骤5a、所述第二会话管理网元或所述AMF网元选择所述第一会话管理网元。
本步骤中，可选的，可以由所述AMF网元触发自身选择所述第一会话管理网元；或者，也可以由所述第二会话管理网元触发所述AMF网元选择第一会话管理网元；或者，还可以由所述第二会话管理网元触发所述第二会话管理网元选择所述第一会话管理网元。例如，所述AMF网元可以根据终端设备的位置(location)以及所述第二会话管理网元的服务区域(service area，SA)，确定触发会话管理网元的选择，并选择所述第一会话管理网元；或者，所述第二会话管理网元终端设备的位置以及所述第二会话管理网元的服务区域，确定触发会话管理网元的选择，并向所述AMF网元发送通知消息，用于通知所述AMF网元进行会话管理网元的选择，所述AMF网元选择所述第一会话管理网元；或者，所述第二会话管理网元可以根据终端设备的位置以及所述第二会话管理网元的服务区域，确定触发会话管理网元的选择，并选择所述第一会话管理网元。
步骤5b、所述AMF网元向所述第一会话管理网元发送更新会话管理上下文请求。
本步骤中，所述更新会话管理上下文请求用于触发所述第一会话管理网元选择I-UPF网元。其中，I-UPF网元可以为与(R)AN网元直接连接的用户面功能网元。可选的，所述更新会话管理上下文请求中还可以包括所述PCF网元的标识。
可选的，当所述更新会话管理上下文请求中包括所述PCF网元的标识时，所述 AMF网元可以通过如下方式获取所述PCF网元的标识：
当由所述AMF网元触发自身选择所述第一会话管理网元时，若与AMF网元接口的PCF网元提供的是终端设备粒度的策略，且终端设备粒度的策略与会话粒度的策略不同，则AMF网元在选择所述第一会话管理网元之前，所述AMF网元可以从所述第二会话管理网元获取所述PCF网元的标识；若终端设备粒度的策略与会话粒度的策略相同，则AMF网元可以不需要从所述第二会话管理网元获取所述PCF网元的标识。另外，所述AMF网元在选择所述第一会话管理网元后是可以获得所述第一会话管理网元的标识，因此可以向所述第一会话管理网元发送更新会话管理上下文请求。
当由所述第二会话管理网元触发所述AMF网元选择第一会话管理网元时，所述第二会话管理网元发送给所述AMF网元的通知消息中可以携带所述PCF网元的标识。
当由所述第二会话管理网元触发所述第二会话管理网元选择所述第一会话管理网元时，所述第二会话管理网元在选择所述第一会话管理网元之后可以将所述第一会话管理网元的标识以及所述PCF网元的标识发送给所述AMF网元。
可选的，当所述更新会话管理上下文请求中不包括所述PCF网元的标识时，所述第一会话管理网元可以通过如下步骤5c获取所述PCF网元的标识。
步骤5c、所述第一会话管理网元从所述第二会话管理网元获取所述PCF网元的标识。
本步骤中，例如，所述第一会话管理网元向所述第二会话管理网元发送标识获取请求，用于请求所述PCF网元的标识，进一步的，所述第一会话管理网元接收所述第二会话管理网元发送的包括所述PCF网元的标识的标识获取响应。
需要说明的是，步骤5c之后还可以包括第一会话管理网元插入流程中的其它步骤，如第一会话管理网元插入I-UPF网元、建立(R)AN网元、Anchor UPF1网元、I-UPF网元之间的用户面连接等。
需要说明的是，上述第一会话管理网元的插入流程可以在如图5A所示的新建分支流程之前。
需要说明的是，在所述第二会话管理网元获取所述PCF网元的标识之后可以对所述PCF网元的标识进行保存。
如图6所示，当终端设备移动到位置2时，通过控制面路径b3完成了建立第一会话，即第二会话的分支，图6中a3表示建立的第二会话的分支的数据路径，此时a2作为第二会话的另一个分支的数据路径。图6为了简化，以所选择的BP UPF网元与所述第二会话对应的与(R)AN网元直接连接的用户面功能网元为相同网元为例，并且在图中记为BP UPF。
本申请提供的会话管理的方法，通过第二会话管理网元向第一会话管理网元发送会话请求消息，所述第一会话管理网元根据所述会话请求消息，为第一会话选择锚点用户面功能网元、分支节点用户面功能网元以及分配终端设备的IP信息，实现了在有两个会话管理网元的场景下建立会话的分支。另外，从图6可以看出，新建立的第二会话的分支还是由第二会话管理网元管理，因此可以重用第二会话管理网元上的会话信息和周边接口，比如重用计费和策略控制(policy and charging control，PCC)的策略、PCF的IP地址等，节省DN授权过程。
图7A为本申请又一实施例提供的会话管理的方法的流程图，图8为本申请又一实施例提供的会话管理的方法的示意图。本实施例中以对于图2所示架构，第一会话管理网元为I-SMF网元，第二会话管理网元为A-SMF网元，第一会话管理网元为第一会话选择锚点用户面功能网元和分支节点用户面功能网元并为第一会话分配终端设备的IP信息。在本实施例中，第一会话可以理解成第二会话的分支。在本实施例中，相同的内容可以参见图5A和图6实施例的描述。如图7A和图8所示，本实施例的方法可以包括：
步骤701、第二会话管理网元确定第二会话的锚点用户面功能网元Anchor UPF1不优，需要选择新的锚点用户面功能网元。
步骤702、所述第二会话管理网元向第一会话管理网元发送会话请求消息。
其中，所述会话请求消息用于请求建立所述第一会话，即所述第二会话的分支。
步骤703、所述第一会话管理网元根据所述会话请求消息，为所述第一会话选择锚点用户面功能Anchor UPF2网元。
步骤704、所述第一会话管理网元向所述Anchor UPF2网元发送N4会话建立请求消息，并接收Anchor UPF2返回的N4会话建立响应消息。
步骤705、所述第一会话管理网元根据所述会话请求消息，为所述第一会话选择分支节点用户面功能BP UPF网元。
步骤706、所述第一会话管理网元向所述BP UPF网元发送N4会话建立请求消息，并接收BP UPF返回的N4会话建立响应消息。
步骤707、所述第一会话管理网元根据所述会话请求消息，为所述第一会话分配终端设备的IP信息。
步骤708、所述第一会话管理网元向所述第二会话管理网元发送会话响应消息。
步骤709、所述第二会话管理网元根据所述IP信息，从PCF网元获取所述IP对应的策略信息。
步骤710、所述第二会话管理网元向所述Anchor UPF1网元发送N4会话修改请求消息，并接收Anchor UPF1返回的N4会话修改响应消息。
步骤711、所述第一会话管理网元向所述Anchor UPF2网元发送N4会话修改请求消息，并接收Anchor UPF2返回的N4会话修改响应消息。
需要说明的是，步骤701-步骤711与步骤501-步骤511类似，在此不再赘述。
步骤712、所述第二会话管理网元向AMF网元发送N11消息。
本步骤中，所述N11消息中携带了所述BP UPF网元的隧道信息。需要说明的是，当步骤705中所选择的BP UPF网元与所述第一会话对应的与(R)AN网元直接连接的用户面功能网元为不同网元时，执行步骤712。当步骤705中所选择的BP UPF网元与所述第一会话对应的与(R)AN网元直接连接的用户面功能网元为同一网元时，由于所述(R)AN网元已经获知了与所述第一会话对应的与(R)AN网元直接连接的用户面功能网元的隧道信息，因此不需要执行步骤712。
步骤713、所述AMF网元根据所述N11消息，向所述(R)AN网元发送N2会话修改请求消息，并接收所述(R)AN网元返回的N2会话修改响应消息。
本步骤中，所述N2会话修改请求消息中携带所述BP UPF网元的隧道信息。需要说明的是，步骤713由步骤712触发，当不执行步骤712时也不执行步骤713。
步骤714、所述AMF根据所述N2会话修改响应消息，向所述第二会话管理网元返回所述N11消息的响应。
步骤715、所述第二会话管理网元向所述第一会话管理网元发送发送指示信息。
本步骤中，所述发送指示信息用于指示所述第一会话管理网元向所述终端设备发送所述IP信息。
步骤716、所述第一会话管理网元通过Anchor UPF2网元向所述终端设备发送路由通告消息。
本步骤中，所述路由通过消息中携带了所述IP信息。
需要说明的是，在本实施例的上述描述中，以第一会话管理网元将IP信息发送给第二会话管理网元，IP信息用于第二会话管理网元获取IP信息对应的策略信息为例。具体的，在步骤708中，第一会话管理网元向第二会话管理网元发送包括IP信息的会话响应消息，在步骤709中，第二会话管理网元根据IP信息从PCF网元获取IP信息对应的策略信息。
可替换地，第一会话管理网元可以将IP信息发送给PCF网元，IP信息用于第一会话管理网元获取IP信息对应的策略信息。具体的，图5A中步骤709替换为步骤709’，相应的，步骤708的会话响应消息中可以不包括IP信息。
步骤709’、所述第一会话管理网元根据所述IP信息，从PCF网元获取所述IP信息对应的策略信息。
本步骤中，需要说明的是，步骤709’可以在步骤707之后，步骤709’与步骤708之间并没有先后顺序的限制。进一步可选的，所述第一会话管理网元可以在如图7A所示的新建分支流程的步骤709’之前获取所述PCF的标识，例如在步骤702中，所述第二会话管理网元向所述第一会话管理网元发送的会话请求消息中可以包括所述PCF网元的标识；或者，所述第一会话管理网元可以在如图7B所示的第一会话管理网元的插入流程中获得PCF网元的标识。
如图7B所示，所述第一会话管理网元的插入流程可以包括如下步骤：
步骤7a、所述第二会话管理网元或所述AMF网元选择所述第一会话管理网元。
需要说明的是，步骤7a与步骤5a类似，在此不再赘述。
步骤7b、所述AMF网元通过所述第二会话管理网元向所述第一会话管理网元发送更新会话管理上下文请求。
需要说明的是，步骤7b与步骤5b的主要区别在于，步骤7b中AMF网元需要通过第二会话管理网元向第一会话管理网元发送更新会话管理上下文请求，其他内容参见步骤5b在此不再赘述。
步骤7c、所述第一会话管理网元从所述第二会话管理网元获取所述PCF网元的标识。
需要说明的是，步骤7c与步骤5c类似，在此不再赘述。
需要说明的是，步骤7c之后还可以包括第一会话管理网元插入流中的其它步骤，如第一会话管理网元插入I-UPF网元、建立(R)AN网元、Anchor UPF1网元、I-UPF 网元之间的用户面连接等。
需要说明的是，上述第一会话管理网元的插入流程可以在如图7A所示的新建分支流程之前。
需要说明的是，在所述第二会话管理网元获取所述PCF网元的标识之后可以对所述PCF网元的标识进行保存。
本申请提供的会话管理的方法，通过第二会话管理网元向第一会话管理网元发送会话请求消息，所述第一会话管理网元根据所述会话请求消息，为第一会话选择锚点用户面功能网元、分支节点用户面功能网元以及分配终端设备的IP信息，实现了在有两个会话管理网元的场景下建立会话的分支。另外，从图8可以看出，新建立的第二会话的分支还是由第二会话管理网元管理，因此可以重用第二会话管理网元上的会话信息和周边接口，比如重用PCC的策略、PCF的IP地址等，节省DN授权过程。
需要说明的是，图7A、图8所示实施例与图5A、图6所示实施例的区别主要在于应用的架构不同。具体的，在图5A、图6所示实施例中，第一会话管理网元与接入和移动管理功能网元之间有接口，第二会话管理网元在会话切换前与接入和移动管理功能网元之间有接口，在会话切换后，第一会话管理网元与接入和移动管理功能网元之间有接口。在图7A、图8所示实施例中，第二会话管理网元与接入和移动管理功能网元之间有接口。因此，在图5A、图6所示实施例中，由第一会话管理网元向接入和移动管理功能网元发送N11消息，而在图7A和图8所示实施例中由第二会话管理网元向接入和移动管理功能网元发送N11消息。并且，在图7A和图8所示实施例中，由于接入和移动管理网元和第二会话管理网元交互，所以第二会话管理网元需要向第一会话管理网元发送发送指示信息，使得第一会话管理网元在接收到发送指示信息后向终端设备发送携带IP信息的路由通告消息。
图9为本申请又一实施例提供的会话管理的方法的流程图，图10为本申请又一实施例提供的会话管理的方法的示意图。本实施例中以对于图1所示架构，第一会话管理网元为I-SMF网元，第二会话管理网元为A-SMF网元，第一会话管理网元为第一会话选择锚点用户面功能网元并为第一会话分配终端设备的IP信息，第一会话与第二会话为不同会话为例。如图9和图10所示，本实施例的方法可以包括：
步骤901、第二会话管理网元确定第二会话的锚点用户面功能网元Anchor UPF1不优，需要触发新的会话的建立。
本步骤中，如图10所示，终端设备在位置1时通过控制面路径B1建立了会话，图6中A1表示会话的数据路径。当终端设备从位置1移动到位置2时，通过控制面路径B2完成了会话切换，图10中A2表示切换后会话的数据路径(第二会话)。此时，第二会话管理网元确定第二会话的锚点用户面功能网元Anchor UPF1不优，需要触发新的会话的建立。需要说明的是，图10中的N3UPF网元表示会话发生切换之后，与接入网网元直接连接的用户面功能网元，不在第二会话管理网元的服务区域，由第一会话管理网元管理。在一种可能的实现方式中，第一会话和第二会话可以同时存在，也可以只建立第一会话。第二会话管理网元根据如下信息的至少一种确定第二会话的锚点用户面功能网元Anchor UPF1不优：终端设备的位置信息、AF的请求，SMF的负载情况，终端设备移出Anchor UPF的服务区域。
步骤902、所述第二会话管理网元通过第一会话管理网元、AMF网元向终端设备发送非接入层(Non-Access-Stratum，NAS)消息。
本步骤中，所述NAS消息中可以包括所述第二会话的ID，所述NAS消息用于所述第二会话管理网元通知终端设备需要建立第一会话。第一会话与第二会话为连接同一个数据网络(Data Network，DN)的会话。需要说明的是，所述第一会话管理网元和接入和移动管理功能网元可以对所述NAS消息进行透传。
步骤903、所述终端设备向所述AMF网元发送NAS消息。
本步骤中，所述NAS消息中可以包括第一会话的ID、DNN、请求类型(Request type)和N1会话管理信息(SM information)。所述NAS消息用于请求建立第一会话。其中，PDU会话建立请求包含在N1会话管理信息中。
步骤904、所述AMF网元通过所述第一会话管理网元向所述第二会话管理网元发送会话管理请求(SM Request)消息。
本步骤中，所述会话管理请求消息除了包括步骤903中所述NAS消息所包含的信息之外，还包括与其他相关的信息，例如AMF ID、终端设备的位置信息(User location information)、接入技术类型(Access Technology Type)等。需要说明的是，所述第一会话管理网元可以对所述会话管理请求消息进行透传。
由于在第二会话进行会话切换的过程中，所述第二会话管理网元需要插入不在所述第二会话管理网元服务区域内的与所述第二会话对应的接入网直接连接的用户面网元，因此所述第二会话管理网元中保存了所述第一会话管理网元的信息，例如，第一会话管理网元的ID。因此所述第二会话管理网元可以根据所述第一会话管理网元的ID向所述第一会话管理网元发送所述会话管理请求消息。
步骤905、所述第二会话管理网元向所述第一会话管理网元发送会话请求消息。
本步骤中，具体的，所述第二会话管理网元可以根据所述第一会话管理网元的ID向所述第一会话管理网元发送会话请求消息。其中，所述会话请求消息用于请求建立所述第一会话。
步骤906、所述第一会话管理网元根据所述会话请求消息，为所述第一会话选择锚点用户面功能Anchor UPF2网元。
步骤907、所述第一会话管理网元向所述Anchor UPF2网元发送N4会话建立请求消息，并接收Anchor UPF2返回的N4会话建立响应消息。
需要说明的是，所述Anchor UPF2网元的隧道信息可以由所述第一会话管理网元分配或者也可以由所述Anchor UPF2网元分配。当由第一会话管理网元分配时，所述第一会话管理网元可以在N4会话建立请求消息中携带所述Anchor UPF2网元的隧道信息。当由所述Anchor UPF2网元分配时，所述Anchor UPF2网元可以在N4会话建立响应消息中携带所述Anchor UPF2网元的隧道信息。本步骤中，所述N4会话建立请求消息中还可以包括向Anchor UPF2网元提供的包检测，UPF执行，报告规则等信息。
步骤908、所述第一会话管理网元根据所述会话请求消息，即根据Anchor UPF2为所述第一会话分配终端设备的IP信息。
需要说明的是，步骤908与步骤906、步骤907之间并没有先后顺序的限制。当 步骤908在步骤906之后时，在步骤908中具体的可以根据步骤906中所选择的Anchor UPF2网元为所述第一会话分配终端设备的IP信息。
步骤909、所述第一会话管理网元向所述第二会话管理网元发送会话响应消息。
本步骤中，所述会话响应消息中包括所述IP信息。所述会话响应消息中还可以包括所述Anchor UPF2网元(R)AN的隧道信息。
步骤910、所述第二会话管理网元根据所述IP信息，从策略控制功能网元获取所述IP对应的策略信息。
步骤911、所述第二会话管理网元通过所述第一会话管理网元向所述AMF网元发送会话管理响应(SM Response)消息。
本步骤中，所述会话管理响应消息中包括了N2接口的会话管理信息(N2SM information)和N1接口的会话管理信息(N1SM information)。具体的，步骤909的所述会话响应消息中包括所述Anchor UPF2网元的隧道信息，所述第二会话管理网元发送给所述第一会话管理网元的会话管理响应消息中的N2接口的会话管理信息中包括了所述Anchor UPF2网元的隧道信息，所述第二会话管理网元发送给所述第一会话管理网元的会话管理响应消息中的N1接口的会话管理信息中包括了所述IP信息，所述第一会话管理网元对将来自所述第二会话管理网元的会话管理响应消息透传给所述接入和移动管理功能网元。
或者，步骤909的所述会话响应消息中未包括所述Anchor UPF2网元的隧道信息，所述第一会话管理网元需要在来自所述第二会话管理网元的会话管理响应消息的N2接口的会话管理信息中增加所述Anchor UPF2网元的隧道信息再发送给所述接入和移动管理功能网元。
所述N1接口的会话管理信息中还包括了PDU会话建立接受(PDU Session Establishment Accept)消息。
步骤912、所述AMF网元向接入网((R)AN)网元发送N2PDU会话请求(N2PDU Session Request)消息。
本步骤中，所述N2PDU会话请求消息中包括了NAS消息以及从步骤911获得的N2接口的会话管理信息。其中，所述NAS消息中包括了从步骤911获得的PDU会话建立接受消息和所述第一会话的ID。
步骤913、所述(R)AN网元为所述第一会话分配所述(R)AN网元的隧道信息。
步骤914、所述(R)AN网元与所述终端设备交互建立无线资源，将步骤912接收到的N2PDU会话请求消息中包括的NAS消息发送给终端设备。
步骤915、所述(R)AN网元向所述AMF网元发送N2PDU会话响应(N2PDU Session Ack)消息。
本步骤中，所述N2接口的PDU会话响应消息中包括了步骤913中所述(R)AN网元为所述第一会话分配的所述(R)AN网元的隧道信息。
步骤916、所述AMF网元向所述第一会话管理网元发送会话管理请求消息。
本步骤中，所述会话管理请求消息中包括了所述(R)AN网元的隧道信息。
步骤917、所述第一会话管理网元向所述Anchor UPF2网元发送N4会话修改请求消息，并接收Anchor UPF2返回的N4会话修改响应消息。
本步骤中，所述N4接口的会话修改请求消息中携带了所述(R)AN网元的隧道信息，目的是将所述接入网网元的隧道信息通知给Anchor UPF2网元。
步骤918、所述第一会话管理网元向所述接入和移动管理功能网元返回会话管理响应消息。
本步骤中，所述会话管理响应消息作为对步骤916中接收到所述接入和移动管理功能网元发送的会话管理请求消息的应答。
需要说明的是，步骤917与步骤918之间并没有先后顺序的限制。
如图10所示，当终端设备移动到位置2时，通过控制面路径B3完成了建立第一会话，图10中A3表示建立的第一会话的数据路径。
与图5A所示实施例类似，在本实施例的上述描述中，以第一会话管理网元将IP信息发送给第二会话管理网元，IP信息用于第二会话管理网元获取IP信息对应的策略信息为例。具体的，在步骤909中，第一会话管理网元向第二会话管理网元发送包括IP信息的会话响应消息，在步骤910中，第二会话管理网元根据IP信息从PCF网元获取IP信息对应的策略信息。
可替换地，第一会话管理网元可以将IP信息发送给PCF网元，IP信息用于第一会话管理网元获取IP信息对应的策略信息。具体的，图9中步骤910替换为步骤910’，相应的，步骤909的会话响应消息中可以不包括IP信息。
步骤910’、所述第一会话管理网元根据所述IP信息，从PCF网元获取所述IP信息对应的策略信息。
本步骤中，需要说明的是，步骤910’可以在步骤908之后，步骤910’与步骤908之间并没有先后顺序的限制。进一步可选的，所述第一会话管理网元可以在如图9所示的新建会话流程的步骤910’之前获取所述PCF的标识，例如在步骤905中，所述第二会话管理网元向所述第一会话管理网元发送的会话请求消息中可以包括所述PCF网元的标识；或者，所述第一会话管理网元可以在如图5B所示的第一会话管理网元的插入流程中获得PCF网元的标识。
本申请提供的会话管理的方法，通过第二会话管理网元向第一会话管理网元发送会话请求消息，所述第一会话管理网元根据所述会话请求消息，为第一会话选择锚点用户面功能网元以及分配终端设备的IP信息，实现了在有两个会话管理网元的场景下建立会话。另外，从图10可以看出，新建的第一会话还是由第二会话管理网元管理，因此可以重用第二会话管理网元上的会话信息和周边接口，比如重用PCC的策略、PCF的IP地址等，节省DN授权过程。
图11为本申请又一实施例提供的会话管理的方法的流程图，图12为本申请又一实施例提供的会话管理的方法的示意图。本实施例中以对于图2所示架构，第一会话管理网元为I-SMF网元，第二会话管理网元为A-SMF网元，第一会话管理网元为第一会话选择锚点用户面功能网元并为第一会话分配终端设备的IP信息，第一会话与第二会话为不同会话为例。在本实施例中，相同的内容可以参见图9和图10实施例的描述。如图11和图12所示，本实施例的方法可以包括：
步骤1101、第二会话管理网元确定第二会话的锚点用户面功能网元Anchor UPF1不优，需要触发新的会话的建立。
需要说明的是，步骤1101与步骤901类似，在此不再赘述。
步骤1102、所述第二会话管理网元通过AMF网元向终端设备发送非接入层(Non-Access-Stratum，NAS)消息。
本步骤中，所述NAS消息中可以包括所述第二会话的ID，所述NAS消息用于所述第二会话管理网元通知终端设备需要建立第一会话。其中第一会话与第二会话为连接到同一个数据网络(Data Network，DN)的会话。需要说明的是，所述接入和移动管理功能网元对所述NAS消息进行透传。
步骤1103、所述终端设备向所述AMF网元发送NAS消息。
本步骤中，所述NAS消息中可以包括第一会话的ID、DNN、请求类型(Request type)和N1会话管理信息(SM information)。所述NAS消息用于请求建立第一会话。其中，PDU会话建立请求包含在N1会话管理信息中。
步骤1104、所述AMF网元向所述第二会话管理网元发送会话管理请求(SM Request)消息。
本步骤中，所述会话管理请求消息除了包括步骤1103中所述NAS消息所包含的信息之外，还包括其他相关的信息，例如AMF ID、终端设备的位置信息(User location information)、接入技术类型(Access Technology Type)等。
步骤1105、所述第二会话管理网元向所述第一会话管理网元发送会话请求消息。
步骤1106、所述第一会话管理网元根据所述会话请求消息，为所述第一会话选择锚点用户面功能Anchor UPF2网元。
步骤1107、所述第一会话管理网元向所述Anchor UPF2网元发送N4会话建立请求消息，并接收Anchor UPF2返回的N4会话建立响应消息。
步骤1108、所述第一会话管理网元根据所述会话请求消息，即根据Anchor UPF2为所述第一会话分配终端设备的IP信息。
需要说明的是，步骤1105-步骤1108与步骤905-步骤908类似，在此不再赘述。
步骤1109、所述第一会话管理网元向所述第二会话管理网元发送会话响应消息。
本步骤中，所述会话响应消息中包括所述IP信息和所述Anchor UPF2网元的隧道信息。(R)AN(R)AN(R)AN(R)AN
步骤1110、所述第二会话管理网元根据所述IP信息，从策略控制功能网元获取所述IP对应的策略信息。
步骤1111、所述第二会话管理网元向所述AMF网元发送会话管理响应(SM Response)消息。
本步骤中，所述会话管理响应消息中包括了N2接口的会话管理信息(N2SM information)和N1接口的会话管理信息(N1SM information)。其中，所述N2接口的会话管理信息中包括了所述Anchor UPF2网元的隧道信息，所述N1接口的会话管理信息中包括了所述IP信息。
所述N1接口的会话管理信息中还包括了PDU会话建立接受(PDU Session Establishment Accept)消息。
步骤1112、所述AMF网元向(R)AN网元发送N2PDU会话请求(N2PDU Session Request)消息。
步骤1113、所述(R)AN网元为所述第一会话分配所述(R)AN网元的隧道信息。
步骤1114、所述(R)AN网元与所述终端设备交互，将步骤1112接收到的N2PDU会话请求消息中包括的NAS消息发送给终端设备。
步骤1115、所述(R)AN网元向所述AMF网元发送N2PDU会话响应(N2PDU Session Ack)消息。
需要说明的是，步骤1112-步骤1115与步骤912-步骤915类似，在此不再赘述。
步骤1116、所述AMF网元通过所述第二会话管理网元向所述第一会话管理网元发送会话管理请求消息。
本步骤中，所述会话管理请求消息中包括了所述(R)AN网元的隧道信息。需要说明的是，所述第二会话管理网元可以对所述会话管理请求消息进行透传。
步骤1117、所述第一会话管理网元向所述Anchor UPF2网元发送N4会话修改请求消息，并接收Anchor UPF2返回的N4会话修改响应消息。
本步骤中，所述N4会话修改请求消息中携带了所述(R)AN网元的隧道信息，目的是将所述(R)AN网元的隧道信息通知给Anchor UPF2网元。
步骤1118、所述第一会话管理网元通过所述第二会话管理网元向所述AMF网元返回会话管理响应消息。
本步骤中，所述会话管理响应消息作为对步骤1116中接收到所述接入和移动管理功能网元发送的会话管理请求消息的应答。需要说明的是，所述第二会话管理网元可以对所述会话管理响应消息进行透传。
与图7A所示实施例类似，在本实施例的上述描述中，以第一会话管理网元将IP信息发送给第二会话管理网元，IP信息用于第二会话管理网元获取IP信息对应的策略信息为例。具体的，在步骤1109中，第一会话管理网元向第二会话管理网元发送包括IP信息的会话响应消息，在步骤1110中，第二会话管理网元根据IP信息从PCF网元获取IP信息对应的策略信息。
可替换地，第一会话管理网元可以将IP信息发送给PCF网元，IP信息用于第一会话管理网元获取IP信息对应的策略信息。具体的，图11中步骤1110替换为步骤1110’，相应的，步骤1109的会话响应消息中可以不包括IP信息。
步骤1110’、所述第一会话管理网元根据所述IP信息，从PCF网元获取所述IP信息对应的策略信息。
本步骤中，需要说明的是，步骤1110’可以在步骤1108之后，步骤1110’与步骤1108之间并没有先后顺序的限制。进一步可选的，所述第一会话管理网元可以在如图11所示的新建会话流程的步骤1110’之前获取所述PCF的标识，例如在步骤1105中，所述第二会话管理网元向所述第一会话管理网元发送的会话请求消息中可以包括所述PCF网元的标识；或者，所述第一会话管理网元可以在如图7B所示的第一会话管理网元的插入流程中获得PCF网元的标识。
本申请提供的会话管理的方法，通过第二会话管理网元向第一会话管理网元发送会话请求消息，所述第一会话管理网元根据所述会话请求消息，为第一会话选择锚点用户面功能网元以及分配终端设备的IP信息，实现了在有两个会话管理网元的场景下建立会话。另外，从图12可以看出新建的第一会话还是由第二会话管理网元管理，因 此可以重用第二会话管理网元上的会话信息和周边接口，比如重用PCC的策略、PCF的IP地址等，节省DN授权过程。
需要说明的是，图11、图12所示实施例与图9、图10所示实施例的区别主要在于应用的架构不同。具体的，在图9、图10所示实施例中，第一会话管理网元与接入和移动管理功能网元之间有接口，第二会话管理网元在会话切换前与接入和移动管理功能网元之间有接口，在会话切换之后第一会话管理网元与接入和移动管理功能网元之间有接口。在图11、图12所示实施例中，第二会话管理网元与接入和移动管理功能网元之间有接口。因此，在图9、图10所示实施例中，第二会话管理网元与AMF网元之间的消息需要经过第一会话管理网元，而在图11和图12所示实施例中第一会话管理网元与AMF网元之间的消息需要经过第二会话管理网元。
需要说明的是，图6、图8、图10和图12中控制面路径不经过用户面网元。
需要说明的是，上述图5-图12所示实施例中，第一会话管理网元是固定的，而第二会话管理网元是根据所述终端设备的移动发生变化的。
可选的，在上述图5-图12所示实施例的基础上，还可以包括：第一会话管理网元在确定需要释放所述第一会话时，释放所述第一会话的用户面资源和所述IP信息。可选的，所述第一会话管理网元可以根据第二会话管理网元发送的释放指示信息，确定释放所述第一会话，所述释放指示信息用于指示释放所述第一会话；或者，所述第一会话管理网元可以根据终端设备的位置信息等确定释放所述第一会话。
图13为本申请又一实施例提供的会话管理的方法的流程图，本实施例在图5-图12所示实施例的基础上，主要描述了由第二会话管理网元变更为第一会话管理网元管理所述第一会话的具体实现方式。如图13所示，本实施例的方法可以包括：
步骤1301、第二会话管理网元向第一会话管理网元发送第一会话的会话上下文。
本步骤中，所述第一会话的会话上下文可以包括：所述第二会话管理网元跟PCF网元交互获取到的相关信息,比如：策略信息，PCF的接口信息，为所述第一会话分配的终端设备的IP信息等。
步骤1302、所述第二会话管理网元向AMF网元发送变更指示信息。
本步骤中，所述变更指示信息用于指示所述第一会话管理网元管理所述第一会话。具体的，所述第二会话管理网元可以在所述第一会话的会话上下文迁移完毕之后，向所述AMF网元发送变更指示信息。可选的，所述AMF网元在接收到所述变更指示信息之后，可以向所述第二会话管理网元回响应。
步骤1303、所述第一会话管理网元向PCF网元发送所述变更指示信息。
需要说明的是，步骤1302与步骤1303之间并没有先后顺序的限制。类似的，所述PCF网元在接收到所述变更指示信息之后，也可以向所述第一会话管理网元回响应。
步骤1304、所述第一会话管理网元确定需要释放所述第一会话。
本步骤中，具体的，当所述第一会话的释放条件被触发时，所述第一会话管理网元确定需要释放所述第一会话。其中，终端设备、PCF网元或所述第一会话管理网元都可以触发第一会话的释放条件。
步骤1305、所述第一会话管理网元释放所述第一会话的用户面资源以及为所述第 一会话分配的终端设备的IP信息。
需要说明的是，本实施例中主要描述管理所述第一会话的会话管理网元由第二会话管理网元变更为第一会话管理网元的相关内容，在第一会话管理网元管理第一会话后，具体的管理方式例如释放所述第一会话的用户面资源以及为所述第一会话分配的IP信息等，可以参见已有的实现方式，在此不再赘述。
需要说明的是，所述第一会话管理网元管理所述第一会话后，与第二会话管理网元类似，也可以向其他会话管理网元发送上述会话请求消息，由其他会话管理网元完成上述所述第一会话管理网元的功能。
本申请提供的会话管理的方法，通过第二会话管理网元向第一会话管理网元发送第一会话的会话上下文，所述第二会话管理网元向AMF网元发送用于指示所述第一会话管理网元管理第一会话的变更指示信息，所述第一会话管理网元向PCF网元发送变更指示信息会话请求消息，使得管理第一会话的会话管理网元由第二会话管理网元变更为第一会话管理网元，实现了在有两个会话管理网元的场景下管理第一会话的会话管理网元的变更。
图14为本申请一实施例提供的会话管理的装置的结构示意图。本实施例提供的装置可以通过软件、硬件或者两者的结合实现成为第一会话管理网元的部分或者全部。如图14所示，该装置可以包括：接收模块1401，用于接收第二会话管理网元发送的会话请求消息；处理模块1402，用于根据所述会话请求消息，为第一会话分配终端设备的互联网协议IP信息，其中，所述第一会话为已建立的第二会话的分支，或者，所述第一会话与所述已建立的第二会话为不同的会话；发送模块1403，用于策略控制功能网元或向所述第二会话管理网元发送所述终端设备的IP信息，所述IP信息用于所述IP信息对应的策略信息的获取。
可选的，接收模块1401，还用于获取所述策略控制功能网元的标识；
发送模块1403，具体用于根据所述策略控制功能网元的标识，向所述策略控制功能网元发送所述终端设备的IP信息。
可选的，接收模块1401获取所述策略控制功能网元的标识，具体包括：
从所述第二会话管理网元接收所述策略控制功能网元的标识；
或者，
从接入和移动管理功能网元接收所述策略控制功能网元的标识。
可选的，处理模块1402，还用于选择所述第一会话对应的锚点用户面功能网元，并确定所述锚点用户面功能网元的隧道信息。
可选的，处理模块1402，还用于选择所述第一会话对应的分支节点用户面功能网元，并确定所述分支节点用户面功能网元的隧道信息。
可选的，发送模块1403，还用于向接入和移动管理功能网元发送所述锚点用户面功能网元的隧道信息。
可选的，发送模块1403，还用于向接入和移动管理功能网元发送所述分支节点用户面功能网元的隧道信息。
可选的，接收模块1401，还用于接收所述第二会话管理网元发送的所述第一会话的会话上下文；发送模块1403，还用于向策略控制功能网元发送变更指示信息，所述 变更指示信息用于指示所述第一会话管理网元管理所述第一会话。
可选的，接收模块1401，还用于接收所述第二会话管理网元发送的释放指示信息，所述释放指示信息用于指示释放所述第一会话；处理模块1402，还用于根据所述释放指示信息，释放所述第一会话的用户面资源和所述IP信息。
可选的，所述第一会话管理网元为管理所述第一会话对应的锚点用户面功能网元和所述终端设备的第二会话对应的与接入网网元直接连接的用户面功能网元的会话管理网元，所述第二会话管理网元为管理所述第二会话对应的锚点用户面功能网元的会话管理网元，所述第一会话和所述第二会话为同一会话或不同会话。
可选的，发送模块1403，还用于通过用户面向所述终端设备发送所述IP信息。
可选的，接收模块1401，还用于接收所述第二会话管理网元发送的发送指示信息，所述发送指示信息用于指示所述第一会话管理网元向所述终端设备发送所述IP信息。
可选的，所述会话请求消息包括以下中的至少一种：所述终端设备的标识、所述第一会话的标识、数据网络名称、会话和业务连续性模式。
本实施例中提供的会话管理的装置，可以用于执行前述图4-图13所示的方法实施例中的任一方法实施例第一会话管理网元侧的技术方案，其实现原理和技术效果与方法实施例类似，在此不再赘述。
本申请还可以提供一种会话管理的装置，该装置可以通过软件、硬件或者两者的结合实现成为第二会话管理网元的部分或者全部。本实施例提供的装置与图14所示装置的结构类似，同样可以包括：处理模块和发送模块。其中，处理模块，用于确定新建第一会话，所述第一会话为已建立的第二会话的分支，或者，所述第一会话与所述已建立的第二会话为不同的会话；发送模块，用于向第一会话管理网元发送会话请求消息，所述会话请求消息用于请求所述第一会话管理网元为所述第一会话分配终端设备的互联网协议IP信息。
可选的，本实施例的装置还可以包括：接收模块，用于接收所述第一会话管理网元发送的所述终端设备的IP信息；所述处理模块，还用于根据所述IP信息，从策略控制功能网元获取所述IP信息对应的策略信息。
可选的，所述发送模块，还用于向所述第一会话管理网元发送策略控制功能网元的标识。
可选的，所述接收模块，还用于接收所述第一会话管理网元发送的所述第一会话的用户面功能网元的隧道信息，所述用户面功能网元为所述第一会话对应的锚点用户面功能网元或分支节点用户面功能网元；
所述发送模块，还用于向接入和移动管理功能网元发送所述第一会话的用户面功能网元的隧道信息。
可选的，所述发送模块，还用于向所述第一会话管理网元发送所述第一会话的会话上下文；所述发送模块，还用于向接入和移动管理功能网元发送变更指示信息，所述变更指示信息用于指示所述第一会话管理网元管理所述第一会话。
可选的，所述发送模块，还用于当确定需要释放所述第一会话时，向所述第一会话管理网元发送释放指示信息，所述释放指示信息用于指示释放所述第一会话。
可选的，所述第一会话管理网元为管理所述第一会话对应的锚点用户面功能网元 和所述终端设备的第二会话对应的与接入网网元直接连接的用户面功能网元的会话管理网元，所述第二会话管理网元为管理所述第二会话对应的锚点用户面功能网元的会话管理网元，所述第一会话和所述第二会话为同一会话或不同会话。
可选的，所述发送模块，还用于向所述第一会话管理网元发送发送指示信息，所述发送指示信息用于指示所述第一会话管理网元向所述终端设备发送所述IP信息。
可选的，所述会话请求消息包括下述中的至少一种：所述终端设备的标识、所述第一会话的标识、数据网络名称、会话和业务连续性模式。
本实施例中提供的会话管理的装置，可以用于执行前述图4-图13所示的方法实施例中的任一方法实施例第二会话管理网元侧的技术方案，其实现原理和技术效果与方法实施例类似，在此不再赘述。
图15为本申请一实施例提供的会话管理网元的结构示意图。如图15所示，该会话管理网元可以包括：处理器1501、存储器1502、接收器1503、发送器1504和至少一个通信总线1505。通信总线1505用于实现元件之间的通信连接。存储器1502可能包含高速RAM存储器，也可能还包括非易失性存储NVM，例如至少一个磁盘存储器，存储器1502中可以存储各种程序，用于完成各种处理功能以及实现本实施例的方法步骤。本实施例中的接收器1503可以为相应的具有通信功能和接收信息功能的输入接口，还可以为第一会话管理网元上的射频模块或者基带模块。本实施例中的发送器1504可以为相应的具有通信功能和接收信息功能的输出接口，还可以为第一会话管理网元上的射频模块或者基带模块。
本实施例中，接收器1503，用于接收第二会话管理网元发送的会话请求消息；
处理器1501，用于根据所述会话请求消息，为第一会话分配终端设备的互联网协议IP信息，其中，所述第一会话为已建立的第二会话的分支，或者，所述第一会话与所述已建立的第二会话为不同的会话；
发送器1504，用于向策略控制功能网元或所述第二会话管理网元发送所述终端设备的IP信息，所述IP信息用于所述IP信息对应的策略信息的获取。
可选的，接收器1503，还用于获取所述策略控制功能网元的标识；
发送器1504，具体用于根据所述策略控制功能网元的标识，向所述策略控制功能网元发送所述终端设备的IP信息。
可选的，接收器1503获取所述策略控制功能网元的标识，具体包括：
从所述第二会话管理网元接收所述策略控制功能网元的标识；
或者，
从接入和移动管理功能网元接收所述策略控制功能网元的标识。
可选的，处理器1501，还用于选择所述第一会话对应的锚点用户面功能网元，并确定所述锚点用户面功能网元的隧道信息。
可选的，处理器1501，还用于选择所述第一会话对应的分支节点用户面功能网元，并确定所述分支节点用户面功能网元的隧道信息。
可选的，发送器1504，还用于向接入和移动管理功能网元发送所述锚点用户面功能网元的隧道信息。
可选的，发送器1504，还用于向接入和移动管理功能网元发送所述分支节点用户 面功能网元的隧道信息。
可选的，接收器1503，还用于接收所述第二会话管理网元发送的所述第一会话的会话上下文；发送器1504，还用于向策略控制功能网元发送变更指示信息，所述变更指示信息用于指示所述第一会话管理网元管理所述第一会话。
可选的，接收器1503，还用于接收所述第二会话管理网元发送的释放指示信息，所述释放指示信息用于指示释放所述第一会话；处理器1501，还用于根据所述释放指示信息，释放所述第一会话的用户面资源和所述IP信息。
可选的，所述第一会话管理网元为管理所述第一会话对应的锚点用户面功能网元和所述终端设备的第二会话对应的与接入网网元直接连接的用户面功能网元的会话管理网元，所述第二会话管理网元为管理所述第二会话对应的锚点用户面功能网元的会话管理网元，所述第一会话和所述第二会话为同一会话或不同会话。
可选的，发送器1504，还用于通过用户面向所述终端设备发送所述IP信息。
可选的，接收器1503，还用于接收所述第二会话管理网元发送的发送指示信息，所述发送指示信息用于指示所述第一会话管理网元向所述终端设备发送所述IP信息。
可选的，所述会话请求消息包括以下中的至少一种：所述终端设备的标识、所述第一会话的标识、数据网络名称、会话和业务连续性模式。
本实施例中提供的会话管理网元，可以用于执行前述图4-图13所示的方法实施例中的任一方法实施例第一会话管理网元侧的技术方案，其实现原理和技术效果与方法实施例类似，在此不再赘述。
本申请还可以提供一种会话管理网元，该会话管理网元与图15所示的会话管理网元的结构类似。其中，处理器，用于确定新建第一会话，所述第一会话为已建立的第二会话的分支，或者，所述第一会话与所述已建立的第二会话为不同的会话；发送器，用于向第一会话管理网元发送会话请求消息，所述会话请求消息用于请求所述第一会话管理网元为所述第一会话分配终端设备的互联网协议IP信息。
可选的，接收器，用于接收所述第一会话管理网元发送的所述终端设备的IP信息；所述处理器，还用于根据所述IP信息，从策略控制功能网元获取所述IP信息对应的策略信息。
可选的，所述发送器，还用于向所述第一会话管理网元发送策略控制功能网元的标识。
可选的，所述接收器，还用于接收所述第一会话管理网元发送的所述第一会话的用户面功能网元的隧道信息，所述用户面功能网元为所述第一会话对应的锚点用户面功能网元或分支节点用户面功能网元；
所述发送器，还用于向接入和移动管理功能网元发送所述第一会话的用户面功能网元的隧道信息。
可选的，所述发送器，还用于向所述第一会话管理网元发送所述第一会话的会话上下文；所述发送器，还用于向接入和移动管理功能网元发送变更指示信息，所述变更指示信息用于指示所述第一会话管理网元管理所述第一会话。
可选的，所述发送器，还用于当确定需要释放所述第一会话时，向所述第一会话管理网元发送释放指示信息，所述释放指示信息用于指示释放所述第一会话。
可选的，所述第一会话管理网元为管理所述第一会话对应的锚点用户面功能网元和所述终端设备的第二会话对应的与接入网网元直接连接的用户面功能网元的会话管理网元，所述第二会话管理网元为管理所述第二会话对应的锚点用户面功能网元的会话管理网元，所述第一会话和所述第二会话为同一会话或不同会话。
可选的，所述发送器，还用于向所述第一会话管理网元发送发送指示信息，所述发送指示信息用于指示所述第一会话管理网元向所述终端设备发送所述IP信息。
可选的，所述会话请求消息包括下述中的至少一种：所述终端设备的标识、所述第一会话的标识、数据网络名称、会话和业务连续性模式。
本实施例中提供的会话管理网元，可以用于执行前述图4-图13所示的方法实施例中的任一方法实施例第二会话管理网元侧的技术方案，其实现原理和技术效果与方法实施例类似，在此不再赘述。
本申请实施例还提供一种会话管理的系统，包括上述实施例提供的会话管理的装置。
本申请还提供一种可读存储介质，可读存储介质中存储有指令，当第一会话管理网元的至少一个处理器执行该指令时，第一会话管理网元执行上述图4-图13所示的方法实施例中任一方法实施例提供的第一会话管理网元侧的会话管理的方法。
本申请还提供一种可读存储介质，可读存储介质中存储有指令，当第二会话管理网元的至少一个处理器执行该指令时，第二会话管理网元执行上述图4-图13所示的方法实施例中任一方法实施例提供的第二会话管理网元侧的会话管理的方法。
本申请还提供一种程序产品，该程序产品包括指令，该指令存储在可读存储介质中。第一会话管理网元的至少一个处理器可以从可读存储介质读取该指令，并执行该指令使得第一会话管理网元实施上述图4-图13所示的方法实施例中任一方法实施例提供的第一会话管理网元侧的会话管理的方法。
本申请还提供一种程序产品，该程序产品包括指令，该指令存储在可读存储介质中。第二会话管理网元的至少一个处理器可以从可读存储介质读取该指令，并执行该指令使得第二会话管理网元实施上述图4-图13所示的方法实施例中任一方法实施例提供的第二会话管理网元侧的会话管理的方法。
在第一会话管理网元或者第二会话管理网元的具体实现中，应理解，处理器可以是中央处理单元(英文：Central Processing Unit，简称：CPU)，还可以是其他通用处理器、数字信号处理器(英文：Digital Signal Processor，简称：DSP)、专用集成电路(英文：Application Specific Integrated Circuit，简称：ASIC)等。通用处理器可以是微处理器或者该处理器也可以是任何常规的处理器等。结合本申请所公开的方法的步骤可以直接体现为硬件处理器执行完成，或者用处理器中的硬件及软件模块组合执行完成。
实现上述各方法实施例的全部或部分步骤可以通过程序指令相关的硬件来完成。前述的程序可以存储于一可读取存储器中。该程序在执行时，执行包括上述各方法实施例的步骤；而前述的存储器(存储介质)包括：只读存储器(英文：read-only memory，缩写：ROM)、RAM、快闪存储器、硬盘、固态硬盘、磁带(英文：magnetic tape)、软盘(英文：floppy disk)、光盘(英文：optical disc)及其任意组合。

Claims (38)

  1. 一种会话管理的方法，其特征在于，包括：
    第一会话管理网元接收第二会话管理网元发送的会话请求消息；
    所述第一会话管理网元根据所述会话请求消息，为第一会话分配终端设备的互联网协议IP信息，其中，所述第一会话为已建立的第二会话的分支，或者，所述第一会话与所述已建立的第二会话为不同的会话；
    所述第一会话管理网元向策略控制功能网元或所述第二会话管理网元发送所述终端设备的IP信息，所述IP信息用于所述IP信息对应的策略信息的获取。
  2. 根据权利要求1所述的方法，其特征在于，所述第一会话管理网元向策略控制功能网元发送所述终端设备的IP信息之前，还包括：
    所述第一会话管理网元获取所述策略控制功能网元的标识；
    所述第一会话管理网元向策略控制功能网元发送所述终端设备的IP信息，包括：
    所述第一会话管理网元根据所述策略控制功能网元的标识，向所述策略控制功能网元发送所述终端设备的IP信息。
  3. 根据权利要求2所述的方法，其特征在于，所述第一会话管理网元获取所述策略控制功能网元的标识，包括：
    所述第一会话管理网元从所述第二会话管理网元接收所述策略控制功能网元的标识；
    或者，
    所述第一会话管理网元从移动管理功能网元接收所述策略控制功能网元的标识。
  4. 根据权利要求1-3任一项所述的方法，其特征在于，所述第一会话管理网元接收第二会话管理网元发送的会话请求消息之后，还包括：
    所述第一会话管理网元选择所述第一会话对应的锚点用户面功能网元，并确定所述锚点用户面功能网元的隧道信息。
  5. 根据权利要求1-4任一项所述的方法，其特征在于，所述第一会话管理网元接收第二会话管理网元发送的会话请求消息之后，还包括：
    所述第一会话管理网元选择所述第一会话对应的分支节点用户面功能网元，并确定所述分支节点用户面功能网元的隧道信息。
  6. 根据权利要求4所述的方法，其特征在于，所述方法还包括：
    所述第一会话管理网元向接入和移动管理功能网元发送所述锚点用户面功能网元的隧道信息。
  7. 根据权利要求5所述的方法，其特征在于，所述方法还包括：
    所述第一会话管理网元向接入和移动管理功能网元发送所述分支节点用户面功能网元的隧道信息。
  8. 根据权利要求1-7任一项所述的方法，其特征在于，所述方法还包括：
    所述第一会话管理网元接收所述第二会话管理网元发送的所述第一会话的会话上下文；
    所述第一会话管理网元向策略控制功能网元发送变更指示信息，所述变更指示信 息用于指示所述第一会话管理网元管理所述第一会话。
  9. 根据权利要求1-7任一项所述的方法，其特征在于，所述方法还包括：
    所述第一会话管理网元接收所述第二会话管理网元发送的释放指示信息，所述释放指示信息用于指示释放所述第一会话；
    所述第一会话管理网元根据所述释放指示信息，释放所述第一会话的用户面资源和所述IP信息。
  10. 根据权利要求1-9任一项所述的方法，其特征在于，所述第一会话管理网元为管理所述第一会话对应的锚点用户面功能网元和所述终端设备的第二会话对应的与接入网网元直接连接的用户面功能网元的会话管理网元，所述第二会话管理网元为管理所述第二会话对应的锚点用户面功能网元的会话管理网元，所述第一会话和所述第二会话为同一会话或不同会话。
  11. 根据权利要求1-10任一项所述的方法，其特征在于，所述方法还包括：
    所述第一会话管理网元通过用户面向所述终端设备发送所述IP信息。
  12. 根据权利要求11所述的方法，其特征在于，所述第一会话管理网元通过用户面向所述终端设备发送所述IP信息之前，还包括：
    所述第一会话管理网元接收所述第二会话管理网元发送的发送指示信息，所述发送指示信息用于指示所述第一会话管理网元向所述终端设备发送所述IP信息。
  13. 根据权利要求1-12任一项所述的方法，其特征在于，所述会话请求消息包括以下中的至少一种：所述终端设备的标识、所述第一会话的标识、数据网络名称、会话和业务连续性模式。
  14. 一种会话管理的方法，其特征在于，包括：
    第二会话管理网元确定新建第一会话，所述第一会话为已建立的第二会话的分支，或者，所述第一会话与所述已建立的第二会话为不同的会话；
    所述第二会话管理网元向第一会话管理网元发送会话请求消息，所述会话请求消息用于请求所述第一会话管理网元为所述第一会话分配终端设备的互联网协议IP信息。
  15. 根据权利要求14所述的方法，其特征在于，所述第二会话管理网元向第一会话管理网元发送会话请求消息之后，还包括：
    所述第二会话管理网元接收所述第一会话管理网元发送的所述终端设备的IP信息；
    所述第二会话管理网元根据所述IP信息，从策略控制功能网元获取所述IP信息对应的策略信息。
  16. 根据权利要求14所述的方法，其特征在于，所述方法还包括：
    所述第二会话管理网元向所述第一会话管理网元发送策略控制功能网元的标识。
  17. 根据权利要求14-16任一项所述的方法，其特征在于，所述方法还包括：
    所述第二会话管理网元接收所述第一会话管理网元发送的所述第一会话的用户面功能网元的隧道信息，所述用户面功能网元为所述第一会话对应的锚点用户面功能网元或者为分支节点用户面功能网元；
    所述第二会话管理网元向接入和移动管理功能网元发送所述第一会话的用户面功 能网元的隧道信息。
  18. 根据权利要求14-17任一项所述的方法，其特征在于，所述方法还包括：
    所述第二会话管理网元向所述第一会话管理网元发送所述第一会话的会话上下文；
    所述第二会话管理网元向接入和移动管理功能网元发送变更指示信息，所述变更指示信息用于指示所述第一会话管理网元管理所述第一会话。
  19. 一种会话管理的装置，其特征在于，包括：
    接收模块，用于接收第二会话管理网元发送的会话请求消息；
    处理模块，用于根据所述会话请求消息，为第一会话分配终端设备的互联网协议IP信息，其中，所述第一会话为已建立的第二会话的分支，或者，所述第一会话与所述已建立的第二会话为不同的会话；
    发送模块，用于向策略控制功能网元或所述第二会话管理网元发送所述终端设备的IP信息，所述IP信息用于所述IP信息对应的策略信息的获取。
  20. 根据权利要求19所述的装置，其特征在于，所述接收模块，还用于获取所述策略控制功能网元的标识；
    所述发送模块，具体用于根据所述策略控制功能网元的标识，向所述策略控制功能网元发送所述终端设备的IP信息。
  21. 根据权利要求20所述的装置，其特征在于，所述接收模块获取所述策略控制功能网元的标识，具体包括：
    从所述第二会话管理网元接收所述策略控制功能网元的标识；
    或者，
    从接入和移动管理功能网元接收所述策略控制功能网元的标识。
  22. 根据权利要求19-21任一项所述的装置，其特征在于，所述处理模块，还用于选择所述第一会话对应的锚点用户面功能网元，并确定所述锚点用户面功能网元的隧道信息。
  23. 根据权利要求19-22任一项所述的装置，其特征在于，所述处理模块，还用于选择所述第一会话对应的分支节点用户面功能网元，并确定所述分支节点用户面功能网元的隧道信息。
  24. 根据权利要求22所述的装置，其特征在于，所述发送模块，还用于向接入和移动管理功能网元发送所述锚点用户面功能网元的隧道信息。
  25. 根据权利要求23所述的装置，其特征在于，所述发送模块，还用于向接入和移动管理功能网元发送所述分支节点用户面功能网元的隧道信息。
  26. 根据权利要求19-25任一项所述的装置，其特征在于，所述接收模块，还用于接收所述第二会话管理网元发送的所述第一会话的会话上下文；
    所述发送模块，还用于向策略控制功能网元发送变更指示信息，所述变更指示信息用于指示所述第一会话管理网元管理所述第一会话。
  27. 根据权利要求19-25任一项所述的装置，其特征在于，所述接收模块，还用于接收所述第二会话管理网元发送的释放指示信息，所述释放指示信息用于指示释放所述第一会话；
    所述处理模块，还用于根据所述释放指示信息，释放所述第一会话的用户面资源 和所述IP信息。
  28. 根据权利要求19-27任一项所述的装置，其特征在于，所述第一会话管理网元为管理所述第一会话对应的锚点用户面功能网元和所述终端设备的第二会话对应的与接入网网元直接连接的用户面功能网元的会话管理网元，所述第二会话管理网元为管理所述第二会话对应的锚点用户面功能网元的会话管理网元，所述第一会话和所述第二会话为同一会话或不同会话。
  29. 根据权利要求19-28任一项所述的装置，其特征在于，所述发送模块，还用于通过用户面向所述终端设备发送所述IP信息。
  30. 一种会话管理的装置，其特征在于，包括：
    处理模块，用于确定新建第一会话，所述第一会话为已建立的第二会话的分支，或者，所述第一会话与所述已建立的第二会话为不同的会话；
    发送模块，用于向第一会话管理网元发送会话请求消息，所述会话请求消息用于请求所述第一会话管理网元为所述第一会话分配终端设备的互联网协议IP信息。
  31. 根据权利要求30所述的装置，其特征在于，所述装置还包括：
    接收模块，用于接收所述第一会话管理网元发送的所述终端设备的IP信息；
    所述处理模块，还用于根据所述IP信息，从策略控制功能网元获取所述IP信息对应的策略信息。
  32. 根据权利要求30所述的装置，其特征在于，所述发送模块，还用于向所述第一会话管理网元发送策略控制功能网元的标识。
  33. 根据权利要求30-32任一项所述的装置，其特征在于，所述接收模块，还用于接收所述第一会话管理网元发送的所述第一会话的用户面功能网元的隧道信息，所述用户面功能网元为所述第一会话对应的锚点用户面功能网元或分支节点用户面功能网元；
    所述发送模块，还用于向接入和移动管理功能网元发送所述第一会话的用户面功能网元的隧道信息。
  34. 根据权利要求30-33任一项所述的装置，其特征在于，所述发送模块，还用于向所述第一会话管理网元发送所述第一会话的会话上下文；
    所述发送模块，还用于向接入和移动管理功能网元发送变更指示信息，所述变更指示信息用于指示所述第一会话管理网元管理所述第一会话。
  35. 根据权利要求30-33任一项所述的装置，其特征在于，所述发送模块，还用于当确定需要释放所述第一会话时，向所述第一会话管理网元发送释放指示信息，所述释放指示信息用于指示释放所述第一会话。
  36. 根据权利要求30-35任一项所述的装置，其特征在于，所述第一会话管理网元为管理所述第一会话对应的锚点用户面功能网元和所述终端设备的第二会话对应的与接入网网元直接连接的用户面功能网元的会话管理网元，所述第二会话管理网元为管理所述第二会话对应的锚点用户面功能网元的会话管理网元，所述第一会话和所述第二会话为同一会话或不同会话。
  37. 根据权利要求30-36任一项所述的装置，其特征在于，所述发送模块，还用于向所述第一会话管理网元发送发送指示信息，所述发送指示信息用于指示所述第一 会话管理网元向所述终端设备发送所述IP信息。
  38. 根据权利要求30-37任一项所述的装置，其特征在于，所述会话请求消息包括下述中的至少一种：所述终端设备的标识、所述第一会话的标识、数据网络名称、会话和业务连续性模式。
PCT/CN2018/092583 2017-06-26 2018-06-25 会话管理的方法、装置、设备及系统 WO2019001381A1 (zh)

Priority Applications (5)

Application Number Priority Date Filing Date Title
EP21179391.4A EP3944665B1 (en) 2017-06-26 2018-06-25 Session management method, apparatus, and system, and device
BR112019027890-7A BR112019027890A2 (pt) 2017-06-26 2018-06-25 método, aparelho, e sistema de gerenciamento de sessão, e dispositivo
EP18823163.3A EP3637853B1 (en) 2017-06-26 2018-06-25 Session management method and apparatus, device, and system
US16/726,439 US11071167B2 (en) 2017-06-26 2019-12-24 Method, apparatus, system, and device for managing a session corresponding to multiple session management function network elements
US17/354,106 US11606839B2 (en) 2017-06-26 2021-06-22 Method, apparatus, system, and device for managing a session corresponding to multiple session management function network elements

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
CN201710494938.7 2017-06-26
CN201710494938 2017-06-26
CN201810235929.0A CN109121170B (zh) 2017-06-26 2018-03-21 会话管理的方法、装置、设备及系统
CN201810235929.0 2018-03-21

Related Child Applications (1)

Application Number Title Priority Date Filing Date
US16/726,439 Continuation US11071167B2 (en) 2017-06-26 2019-12-24 Method, apparatus, system, and device for managing a session corresponding to multiple session management function network elements

Publications (1)

Publication Number Publication Date
WO2019001381A1 true WO2019001381A1 (zh) 2019-01-03

Family

ID=64741052

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/CN2018/092583 WO2019001381A1 (zh) 2017-06-26 2018-06-25 会话管理的方法、装置、设备及系统

Country Status (1)

Country Link
WO (1) WO2019001381A1 (zh)

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20170086049A1 (en) * 2015-09-18 2017-03-23 Huawei Technologies Co., Ltd. System and methods for reliable communication with mobility along a predictable route
CN106792936A (zh) * 2016-12-08 2017-05-31 上海华为技术有限公司 一种保持业务连续性的pgw切换方法及通信设备

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20170086049A1 (en) * 2015-09-18 2017-03-23 Huawei Technologies Co., Ltd. System and methods for reliable communication with mobility along a predictable route
CN106792936A (zh) * 2016-12-08 2017-05-31 上海华为技术有限公司 一种保持业务连续性的pgw切换方法及通信设备

Non-Patent Citations (3)

* Cited by examiner, † Cited by third party
Title
ERICSSON: "23.501: SMF Service Areas", SA WG2 MEETING #121 S2-173006, 9 May 2017 (2017-05-09), XP051268491 *
ERICSSON: "SMF Service Areas", SA WG2 MEETING #122 S2-174193, 20 June 2017 (2017-06-20), XP051303048 *
See also references of EP3637853A4 *

Similar Documents

Publication Publication Date Title
US11071167B2 (en) Method, apparatus, system, and device for managing a session corresponding to multiple session management function network elements
KR102275935B1 (ko) 세션 관리 방법, 상호 연동 방법, 및 네트워크 장치
EP3562182B1 (en) Communication path switching method
US20220174575A1 (en) Data transmission method, terminal device, and network device
CN110662308B (zh) 一种通信方法及装置
CN105409285B (zh) 一种控制承载切换的设备和控制方法
WO2017201722A1 (zh) 一种通信控制的方法及相关网元
CN110876159B (zh) 一种提高时延确定性的方法及装置
US20230019215A1 (en) TSC-5G QoS MAPPING WITH CONSIDERATION OF ASSISTANCE TRAFFIC INFORMATION AND PCC RULES FOR TSC TRAFFIC MAPPING AND 5G QoS FLOWS BINDING
CN105874830A (zh) 一种移动性管理的方法、装置及系统
CN111510977B (zh) 一种移动性管理方法及装置
CN109845389B (zh) 一种通信方法及装置
EP3962157B1 (en) Mdbv determining methods and apparatuses
WO2015003590A1 (zh) 一种路径切换的方法、设备和用户设备
CN114698025A (zh) 一种通信方法及节点
US20220116798A1 (en) Data transmission method, apparatus, and device
CN110582126B (zh) 一种通信方法及装置
CN113473525B (zh) 一种数据传输的方法及装置
WO2022170798A1 (zh) 确定策略的方法和通信装置
CN114424498B (zh) 数据传输方法、装置、系统和存储介质
CN112469077B (zh) 一种业务数据包转发的方法及装置
WO2019001381A1 (zh) 会话管理的方法、装置、设备及系统
CN116939505A (zh) 一种通信方法及装置

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 18823163

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: DE

REG Reference to national code

Ref country code: BR

Ref legal event code: B01A

Ref document number: 112019027890

Country of ref document: BR

ENP Entry into the national phase

Ref document number: 2018823163

Country of ref document: EP

Effective date: 20200107

ENP Entry into the national phase

Ref document number: 112019027890

Country of ref document: BR

Kind code of ref document: A2

Effective date: 20191226