Methods, systems, and devices for wireless communication are described. A method may include determining to modify current-allowed network slices used by a user equipment (UE) based on a network-trigger; identifying new-allowed network slices for the UE based on the determining; selecting a target access and mobility management function (AMF) based on the new-allowed network slices, the target AMF is accessible by the source AMF; and triggering an AMF relocation based on the selecting.

Methods, systems, and devices for wireless communication are described. A method may include determining to modify current-allowed network slices used by a user equipment (UE) based on a network-trigger; identifying new-allowed network slices for the UE based on the determining; selecting a target access and mobility management function (AMF) based on the new-allowed network slices, the target AMF is accessible by the source AMF; and triggering an AMF relocation based on the selecting.

The present disclosure relates to a pre-5.sup.th-Generation (5G) or 5G communication system to be provided for supporting higher data rates Beyond 4.sup.th-Generation (4G) communication system such as Long Term Evolution (LTE). The embodiments in the present disclosure allow to transfer remaining data between different base stations in a dual-registration interworking process, which provides terminal mobility between 4G and 5G networks without a data loss. Further, it provides the terminal mobility with no data loss without changing 5G and 4G base station implementation through addition of a simple function of new equipment, such as SMF and UPF. Further, it supports different QoS and forwarding path units in the 5G/4G networks without changing 5G and 4G base station functions. Further, it exempts additional function implementation costs for re-ordering in a terminal and a network through in-order delivery of packets to the terminal without changing the packet order during 4G-5G network movement.

The present disclosure relates to a pre-5.sup.th-Generation (5G) or 5G communication system to be provided for supporting higher data rates Beyond 4.sup.th-Generation (4G) communication system such as Long Term Evolution (LTE). The embodiments in the present disclosure allow to transfer remaining data between different base stations in a dual-registration interworking process, which provides terminal mobility between 4G and 5G networks without a data loss. Further, it provides the terminal mobility with no data loss without changing 5G and 4G base station implementation through addition of a simple function of new equipment, such as SMF and UPF. Further, it supports different QoS and forwarding path units in the 5G/4G networks without changing 5G and 4G base station functions. Further, it exempts additional function implementation costs for re-ordering in a terminal and a network through in-order delivery of packets to the terminal without changing the packet order during 4G-5G network movement.

This application provides a method for controlling a terminal to use a wireless network, a system, and a related device. The method includes: obtaining, by a network decision device, service information of a terminal, constructing network use indication information, and delivering the network use indication information to a network trigger device; and triggering, by the network trigger device based on the network use indication information, the terminal to use a wireless network corresponding to the service information. According to the method, an operator can assign, based on a service requirement of the operator, the terminal to use a specific wireless network, so that the terminal can use in time a wireless network that is consistent with a requirement of the operator. This helps improve network use efficiency for the operator, and can prevent a service of the terminal from being affected.

This application provides a method for controlling a terminal to use a wireless network, a system, and a related device. The method includes: obtaining, by a network decision device, service information of a terminal, constructing network use indication information, and delivering the network use indication information to a network trigger device; and triggering, by the network trigger device based on the network use indication information, the terminal to use a wireless network corresponding to the service information. According to the method, an operator can assign, based on a service requirement of the operator, the terminal to use a specific wireless network, so that the terminal can use in time a wireless network that is consistent with a requirement of the operator. This helps improve network use efficiency for the operator, and can prevent a service of the terminal from being affected.

A method for session method, a terminal device and a network device are provided. The method includes: sending, by a terminal device, first information to a first network device, wherein the first indication is used for requesting for establishing a packet data network (PDN) connection; receiving, by the terminal device, second information from the network device, wherein the second information indicates that the request, initiated by the terminal device, for establishing the PDN connection is accepted, the second information includes first indication information for indicating whether a protocol data unit (PDU) session corresponding to the PDN connection supports multi-access (MA) after the terminal devices moves from a 4.sup.th-generation (4G) network to a 5.sup.th-generation (5G) network, and the PDU session, if supporting the MA, is able to implement data transmission with a 3rd generation partnership project (3GPP) network and a non-3GPP network simultaneously.

A method at an Access and mobility Management Function (AMF) for facilitating a Protocol Data Unit (PDU) session procedure for a User Equipment (UE) in a 5th Generation System (5GS) network, wherein the 5GS network is interworking with an Evolved Packet System (EPS) network, and a Packet Data Network Gateway Control plane Function+Session Management Function (PGW-C+SMF) supporting the interworking is selected for managing the PDU session. The method comprises determining whether the PDU session supports interworking with the EPS network, based on at least one of a capability of the UE and a subscription data of the UE; and sending an indication which indicates whether the PDU session supports interworking with the EPS network to the PGW-C+SMF.

A method at an Access and mobility Management Function (AMF) for facilitating a Protocol Data Unit (PDU) session procedure for a User Equipment (UE) in a 5th Generation System (5GS) network, wherein the 5GS network is interworking with an Evolved Packet System (EPS) network, and a Packet Data Network Gateway Control plane Function+Session Management Function (PGW-C+SMF) supporting the interworking is selected for managing the PDU session. The method comprises determining whether the PDU session supports interworking with the EPS network, based on at least one of a capability of the UE and a subscription data of the UE; and sending an indication which indicates whether the PDU session supports interworking with the EPS network to the PGW-C+SMF.

A network device may receive an indication of movement of a user device, associated with multiple packet data unit (PDU) sessions, from a first radio access network (RAN) to a second RAN, and may maintain, based on the indication, a particular PDU session, of the multiple PDU sessions, associated with a default flow. The network device may release, based on the indication, the multiple PDU sessions other than the particular PDU session, and may handle the multiple PDU sessions, other than the particular PDU session, in accordance with a handling option.