Abstract: Embodiments of this application relate to the field of communications technologies, and disclose a relay device selection method, and a user equipment, so that UE can select and update with an allowed S-NSSAI of the UE. The method may include: obtaining by UE, M pieces of first indication information, each indicates one allowed network slice of the UE; receiving by the UE, first messages sent by L relay devices, comprising N pieces of second indication information, wherein each indicates one allowed network slice of the relay device; and selecting by the UE, a random first relay device as a target relay device based on the M pieces of first indication information and the L pieces of first messages.

Abstract: Embodiments of the present invention relate to the field of communications technologies, and in particular, to a method, an apparatus, and a system for establishing a session, to resolve a problem in the prior art that efficiency is low because an AMF entity needs to reselect an SMF entity when forwarding a first message. The method includes: receiving, by a mobility management function AMF entity, a first message sent by user equipment UE, where the first message carries identifier information, the identifier information is used to instruct the AMF entity to send the first message to a session management function SMF entity, and the first message is used to instruct the SMF entity to re-establish a session with the UE based on the identifier information by using a first user plane function UPF entity; and sending, by the AMF entity based on the identifier information, the first message to the SMF entity associated with the identifier information.

Abstract: A protocol data unit (PDU) type setting method, a user equipment (UE) policy setting method, and a related entity, where the PDU type setting method includes: setting, by UE, a requested PDU type of a PDU session in a process of establishing the PDU session, where the requested PDU type of the PDU session is set by the UE based on a first condition, the first condition includes an Internet Protocol (IP) version corresponding to an application, and the application is associated with the PDU session. In the embodiments of the present disclosure, the requested PDU type of the PDU session can be consistent with a PDU type requested by the application, such that the application can normally perform communication.

Abstract: This application discloses a network access method and device. The method includes: receiving, by a first management entity, a first request message sent by a first terminal, where the first request message includes at least a first identifier of a second terminal; determining, by the first management entity based on a first condition, whether the second terminal can access a network by using the first terminal, where the first condition includes at least that the first identifier of the second terminal belongs to a list of at least one terminal having a trust relationship with the first terminal, and the list includes at least a first identifier of the at least one terminal having the trust relationship with the first terminal. Legality of access by a wearable device to a network by using a user terminal can be authenticated by using the method and device in this application.

Abstract: A session management method by a terminal in which a network initiates a session deactivation procedure to deactivate one or more sessions of a terminal. After the terminal in an inactive mode establishes an RRC connection to a new second base station, the second base station indicates, through RRC connection reconfiguration, the terminal to delete related information of the to-be-deactivated session, or the second base station uses an RRC connection resume response message to carry an identifier of the one or more to-be-deactivated sessions, and the terminal deletes session-related information corresponding to the identifier of the one or more to-be-deactivated sessions. In this way, the terminal is enabled to process the related information of the to-be-deactivated session in a timely manner.

Abstract: This application discloses a PDU session establishment method and apparatus. The method includes: receiving, by a terminal device in a process of establishing a PDN connection in a first system, an access type that is sent by a core network device and that corresponds to the PDN connection in a second system; and when the terminal device moves to the second system, establishing, by the terminal device, a PDU session in the second system via an access network indicated by the access type, where the PDU session is associated with the PDN connection. Implementation of the present invention can increase a success rate of establishing a PDU session.

Abstract: This application provides a data route selection method and apparatus, and relates to the field of communications technologies, so as to resolve a problem of an excessively long transmission delay for an application program that initiates a data transmission request relatively later. The data route selection method includes: detecting, by a terminal, that information about an application matches a traffic descriptor; determining, by the terminal, a first route selection components for the application; and routing, by the terminal, traffic of the application on a first protocol data unit PDU session. The first PDU session matches the first route selection components. This application is applicable to a terminal.

Abstract: A session establishment method includes receiving, by a mobility management function AMF entity, a first message sent by user equipment UE, where the first message carries identifier information, the identifier information is used to instruct the AMF entity to send the first message to a session management function SMF entity, and the first message is used to instruct the SMF entity to re-establish a session with the UE based on the identifier information by using a first user plane function UPF entity; and sending, by the AMF entity based on the identifier information, the first message to the SMF entity associated with the identifier information.

Abstract: Embodiments of the present disclosure provide a communication method for requesting a relay service, comprising: obtaining a first MBMS SAI set, where the first MBMS SAI set is an MBMS SAI set of an MBMS service area of a first MBMS; receiving a second MBMS SAI set sent by second user equipment, where the second MBMS SAI set is an MBMS SAI set to which a camping cell of the second user equipment belongs; and sending a first request message to the second user equipment when the first MBMS SAI set includes at least one SAI in the second MBMS SAI set, where the first request message is used to request the second user equipment to provide the first user equipment with a relay service for the first MBMS.

Abstract: In one embodiment, a method for wireless network selection includes obtaining, by a user equipment (UE) from a visitor access network discovery and selection function (V-ANDSF) server, a visitor policy and creating a wireless local area network (WLAN) priority list in accordance with the visitor policy, a home policy, and a priority indicator. The method also includes selecting a WLAN from the priority list as a selected network.

Abstract: The present disclosure describes methods, devices, and systems for signal strength measurement. An example method includes: broadcasting, by a first relay device, a first message, wherein the first message is used by a first remote device to discover the first relay device; establishing, by the first relay device, a connection to the first remote device; and sending, by the first relay device, a second message, wherein the second message is used by the first remote device to measure signal strength of a link between the first remote device and the first relay device.

Abstract: A connection management method includes: accessing, by UE, a network using a first base station, where the UE is in an RRC inactive state; accessing, by the UE, a network using a second base station, where the second base station does not support the RRC inactive state; and sending, by the UE, a first request message to a first core network entity using the second base station, so that the first core network entity releases a connection to the first base station based on the first request message.

Abstract: A protocol data unit (PDU) type setting method, a user equipment (UE) policy setting method, and a related entity, where the PDU type setting method includes: setting, by UE, a requested PDU type of a PDU session in a process of establishing the PDU session, where the requested PDU type of the PDU session is set by the UE based on a first condition, the first condition includes an Internet Protocol (IP) version corresponding to an application, and the application is associated with the PDU session. In the embodiments of the present disclosure, the requested PDU type of the PDU session can be consistent with a PDU type requested by the application, such that the application can normally perform communication.

Abstract: The method includes: when user equipment UE has a first protocol data unit PDU session, sending, by the UE, a service request message to an access and mobility management function AMF entity; receiving, by the UE, a first message sent by the AMF entity; and determining, by the UE based on the first message, to re-establish or modify the first PDU session. In the embodiments of the present invention, the UE sends the service request message to the AMF entity, and then the AMF entity sends, to the UE, the first message used to determine to re-establish or modify the first PDU session.

Abstract: A session establishment method includes receiving, by a mobility management function AMF entity, a first message sent by user equipment UE, where the first message carries identifier information, the identifier information is used to instruct the AMF entity to send the first message to a session management function SMF entity, and the first message is used to instruct the SMF entity to re-establish a session with the UE based on the identifier information by using a first user plane function UPF entity; and sending, by the AMF entity based on the identifier information, the first message to the SMF entity associated with the identifier information.

Abstract: A method for moving between communications systems and an apparatus, where the method includes: receiving, by a user equipment (UE), a first message, where the first message is used to set up or modify a first evolved packet system (EPS) bearer for the UE in the first communications system, and the first message includes first quality of service (QoS) flow information that is of the second communications system and corresponds to the first EPS bearer; storing, by the UE, the first QoS flow information; moving, by the UE, from the first communications system to the second communications system; and determining, by the UE based on a first condition, QoS flow information used by the UE in the second communications system, where the first condition includes the first QoS flow information.

Abstract: A registration method, a session establishment method, a terminal, and an access and mobility management function (AMF) entity, where the method includes sending, by a terminal, a first message to the AMF entity, where the first message includes first information, first network slice selection information, and second network slice selection information, the first information includes information for requesting to establish a protocol data unit (PDU) session, the first network slice selection information is used by the AMF entity to select a first session management control function (SMF) entity, and the second network slice selection information is used by the AMF entity to select a second SMF entity, and receiving, by the terminal, a second message from the AMF entity, where the second message includes second information, and the second information includes PDU session establishment accept information.

Abstract: An inter-communications-system handover method implements handover of user equipment (UE) between communications systems and deletes a session incapable of being handed over, The inter-communications-system handover method includes determining, by UE, whether a first session exists in a first communications system, where the first session is capable of being handed over from the first communications system to a second communications system; and sending, by the UE, a first message to a first core network device of the second communications system when determining that the first session exists, where the first message is used to establish a second session in the second communications system, and the second session corresponds to the first session.

Abstract: A registration method includes sending, by a terminal, a first message to the AMF entity, where the first message includes first information, first network slice selection information, second network slice selection information, and information for requesting to establish a protocol data unit (PDU) session. The first network slice selection information is used by the AMF entity to select a first session management control function (SMF) entity, and the second network slice selection information is used by the AMF entity to select a second SMF entity. The method further includes receiving, by the terminal, a second message from the AMF entity, where the second message includes second information, and the second information includes PDU session establishment accept information.

Abstract: Embodiments provide a data transmission method. The method includes: receiving, by a core network entity, a first message sent by a first user equipment (UE); and setting up, by the core network entity, a target bearer on the first UE according to the first message, so that a second UE transmits data using the target bearer.