KR20190118507A - Packet data unit session release method and network entity performing the same - Google Patents

Abstract

Disclosed are a packet data unit (PDU) session release method in a network and a network entity performing the same. When a multi-access PDU session (MA-PDU session) is established, an AMF (access and mobility management function) may receive a PDU session release request message including an access type that is an access network corresponding to a session to be released during the MA-PDU session from the terminal. The AMF may send a first message including an access type to be released to a session management function (SMF).

Description

PACKET DATA UNIT SESSION RELEASE METHOD AND NETWORK ENTITY PERFORMING THE SAME}

The present invention relates to a PDU session release method in a network and a network entity performing the same.

Recently, standardization on 5G network technology is in progress. In this 5G network, standard work is underway to support access traffic steering, switching and splitting (ATSSS) between the 3GPP access network and the Non-3GPP access network.

Traffic steering refers to the ability to forward new data traffic over a new access network, and traffic switching refers to the ability to transfer all current data traffic that is currently in transit to another access network. Traffic splitting refers to a function of distributing one data traffic through multiple access networks.

In order to provide traffic (data, voice, etc.) to a user equipment (UE) in a 5G network, a packet data unit (PDU) session configuration is basically established between the user equipment (UE) and a data network. need. After the service is provided, the PDU session needs to be released.

The existing PDU session configuration is established only through the terminal and one access network (3GPP access network or Non-3GPP access network), through which a single access PDU session (SA-PDU Session) is established. A plurality of single access PDU sessions (SA-PDU Sessions) may be configured in one UE, and a plurality of single access PDU sessions may be distinguished through PDU Session Identifiers, respectively. When the terminal finishes providing the service or needs to change the user traffic session, the PDU session generated as described above may be triggered by the terminal or the network to be modified or released.

However, since a single access PDU session (SA-PDU Session) is configured with only one access network, user traffic belonging to the corresponding PDU session cannot be transmitted or received through two or more access networks. Accordingly, it is difficult to provide a service supporting the ATSSS function. In order to support the ATSSS function, the same PDU session generated over two or more accesses is required. Such a PDU session is called a multi-access PDU session (MA-PDU session).

An object of the present invention is to provide a method for releasing a MA-PDU session generated for an ATSSS function and a network entity for performing the same.

An object of the present invention is to provide a method for converting a MA-PDU session generated for an ATSSS function into a SA-PDU session and a network entity performing the same.

According to an embodiment of the present invention, a method of releasing a Packet Data Unit (PDU) session in a network is provided. The method may include a PDU including an access type that is an access network corresponding to a session to be released during the MA-PDU session by an access and mobility management function (AMF) when a multi-access PDU session (MA-PDU session) is established. The method may include receiving a session release request message from a terminal, and transmitting, by the AMF, a first message including the access type to a session management function (SMF).

The method may further include triggering a PDU session release when the SMF receives the first message, and sending, by the SMF, a session modification request message including the access type to a user plane function (UPF). It may include.

The access type may be any one of a 3GPP access network, a Non-3GPP access network, and both the 3GPP access network and the Non-3GPP access network.

The access type may be one of a first access network and a second access network, and the PDU session release request message may be received through the first access network.

The method may further include the AMF receiving a second message from the SMF in response to the first message, wherein the second message may include a PDU session release command message and the access type. have.

The method may further include transmitting, by the AMF, a third message requesting release of resources to the first access network, and wherein the first access network sends the PDU session release command message to the terminal. Can be.

The method further includes the AMF receiving a charge message for the third message from the first access network, and the AMF sending a fourth message to the SMF including the access type. Can be.

The method may further include: receiving, by the AMF, a PDU session release amount message from the terminal, sending, by the AMF, a third message including the access type to the SMF, and wherein the AMF corresponds to the access type. The method may further include receiving from the SMF that the PDU session has been released.

The access type may be both a first access network and the second access network, and the PDU session release request message may be received via the first access network.

The method may further comprise the AMF receiving a second message from the SMF in response to the first message, and the AMF receiving a third message from the SMF, wherein the second message May include a PDU session release command message, and the access type, and the third message may include the access type.

The method may include: sending, by the AMF, a fourth message requesting resource release to the second access network, the AMF receiving a charge message for the fourth message from the second access network; and The AMF may further include transmitting a fifth message including the access type to the SMF.

The method may further include: transmitting, by the AMF, a fourth message requesting resource release to the first access network, transmitting, by the first access network, the PDU session release command message to the terminal; The method may further include receiving a charge message for a fourth message from the first access network, and transmitting, by the AMF, a fourth message including the access type to the SMF.

The method may include: receiving, by the AMF, a PDU session release amount message from the terminal, transmitting, by the AMF, a fifth message including the access type to the SMF, and wherein the AMF corresponds to the access type. The method may further include receiving from the SMF that the PDU session has been released.

The first message may be an Nsmf_PDUSession_UpdateSMContext message.

According to another embodiment of the present invention, a method of releasing a packet data unit (PDU) session in a network is provided. The method may include a PDU session release request including an access type that is an access network corresponding to a session to be released by the Session Management Function (SMF) when a multi-access PDU session (MA-PDU session) is established. And receiving, by the SMF, in response to the PDU session release request, performing a PDU session release.

The access type may be any one of a first access network, a second access network, and both of the first access network and the second access network.

The method may further include sending, by the SMF, an Nsmf_PDUSession_UpdateSMContext response message to an Access and Mobility Management Function (AMF) in response to the PDU session release request, wherein the Nsmf_PDUSession_UpdateSMContext response message is a PDU session release command message, and It may include the access type.

The method may further include transmitting, by the SMF, a Namf_Communication_N1N2MessageTransfer message including the access type to an access and mobility management function (AMF).

According to another embodiment of the present invention, there is provided a network entity for controlling the release of a Packet Data Unit (PDU) session in a network. The network entity includes a processor for controlling to release the MA-PDU session when a multi-access PDU session (MA-PDU session) is established in a terminal, and an access network corresponding to a session to be released during the MA-PDU session. And a network interface for receiving a PDU session release request including an in access type, and the processor may control to release the PDU session corresponding to the access type.

According to the embodiment of the present invention, it is possible to easily provide the release of the MA-PDU session generated to support the ATSSS function and the switch to the SA-PDU session.

1 is a diagram illustrating a 5G network according to an embodiment of the present invention.
2 is a flowchart illustrating a method of releasing a MA-PDU session according to an embodiment of the present invention.
3 is a flowchart illustrating a method of releasing a MA-PDU session according to another embodiment of the present invention.
4 illustrates a computing system in accordance with an embodiment of the present invention.

DETAILED DESCRIPTION Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention. In the drawings, parts irrelevant to the description are omitted in order to clearly describe the present invention, and like reference numerals designate like parts throughout the specification.

Throughout the specification, a user equipment (UE) is a mobile terminal (MT), a mobile station (MS), an advanced mobile station (AMS), a high reliability mobile station (HR). -MS), subscriber station (SS), portable subscriber station (PSS), access terminal (AT), etc., and may be referred to as a terminal, MT, AMS, HR-MS, SS May include all or part of the functionality of a PSS, AT, UE, or the like.

In addition, a base station (BS) may be an advanced base station (ABS), a high reliability base station (HR-BS), a node B (node B), an advanced node B (evolved node B, eNodeB), access point (AP), radio access station (RAS), base transceiver station (BTS), mobile multihop relay (MMR) -BS, relay serving as a base station station, RS), a high reliability relay (HR-RS) serving as a base station, etc., and may also be referred to as BS, ABS, Node B, eNodeB, AP, RAS, BTS, MMR-BS, RS It may also include all or part of the function, such as HR-RS.

1 is a diagram illustrating a 5G network according to an embodiment of the present invention.

As shown in FIG. 1, the 5G network 1000 according to an embodiment of the present invention includes a terminal (UE) 100, an access network (AN) 200, and an access mobility management function (AMF). Management Function (310), Session Management Function (SMF, Session Management Function) (320), User Plane Function (UPF, User Plane Function) (330), Data Network (DN, Data Network) 400, Policy Control Function (PCF, Policy Control Function) 500, and Unified Data Management (UDM) 600.

The terminal (UE) 100 may access the network via the access network 200. Access network 200 includes a 3GPP access network 210 and a Non-3GPP access network 220. The terminal may connect to the cellular mobile radio access network via the 3GPP access network 210. In addition, the terminal 100 may access the WLAN access network through the Non-3GPP access network 220. Non-3GPP access network 220 includes Non-3GPP InterWorking Function (N3IWF) 221 for N3 and N2 interfaces with UPF 330 and AMF 310 by the 5G core network common interface principle.

AMF 310 and SMF 320 are network entities that process control signals. The AMF 310 performs authentication, access, and mobility control functions. The SMF 320 has a session control function (set / change / release of a session) and performs signaling procedures for traffic path setting and traffic movement management. That is, the SMF 320 controls the data path between the UPF 330 and the access network 200. The AMF 310 has N1 which is a non-access stratum (NAS) signal interface with the terminal 100.

The UPF 330 is a network entity in the data plane that collectively accommodates multiple access networks 210, 220 through the N3 interface. The UPF 330 connects a data plane between the multiple access networks 210 and 220 and the DN 400, through which traffic of the terminal 100 (ie, a user) may be transmitted and received.

The UPF 330 and the access network 200 receive a control rule for traffic between the terminal 100 and the UPF 330 through the N4 and N2 interfaces, respectively, from the SMF 320 and the traffic through the received control rule. Performs functions such as detection, routing and QoS control.

The PCF 500 is connected to the SMF 320 via the N7 signal interface and controls session, mobility, and QoS related policies. The PCF 500 may transmit the policy and charging control rule (PCC) policy required for the SMF 320 to generate the ATSSS rule to the SMF 320.

The UDM 600 is connected to the SMF 320 through the N10 signal interface and manages user information management such as subscription information of the UE 100 and a policy of the UE. The UDM 600 may transmit information on the profile and subscription of the UE 100 for the ATSSS to the SMF 320.

As such, the 5G network system according to the embodiment of the present invention is an integrated structure that simultaneously accommodates the 3GPP access 210 network and the Non-3GPP access network 220. In order to provide ATSSS function in such an integrated structure, a multi-access PDU session (MA-PDU Session) setting procedure is required, and a procedure for converting or releasing the configured PDU session into a SA-PDU session is also required. 2 and 3, a method of switching or releasing a SA-PDU session in a state in which a MA-PDU session is established will be described.

2 is a flowchart illustrating a method of releasing a MA-PDU session according to an embodiment of the present invention.

The MA-PDI session release method of FIG. 2 relates to a method of releasing one access from a MA-PDU session and switching to a SA-PDU session.

First, in FIG. 2, a UE (UE) 100 is already registered in a 5G network through a 3GPP access network 210 and a Non-3GPP access network 220, and is connected to a MA-PDU session by various MA-PDU session creation procedures. It is assumed that the state is set (S200). The generated MA-PDU session may have the same PDU session ID (ID, identifier). In this state in which the MA-PDU session is established, the terminal 100 determines to release one of the MA-PDU sessions for a predetermined cause. Meanwhile, a network other than the terminal 100 may determine to release one access of the MA-PDU session.

The terminal 100 transmits a PDU session release request message to the AMF 310 through the access network 210 or 220 to be released within the MA-PDU session (S201). For convenience of explanation in the following description, it is assumed that an access network to be released within a MA-PDU session is a 3GPP access network. Accordingly, in FIG. 2, a PDU session release request message may be sent over the 3GPP access network 210.

The PDU Session Release Request message is an N1 NAS message and includes a PDU session ID and an Access Type. Here, the access type means an access type to be released within the MA-PDU session. That is, the Access Type indicates whether the MA-PDU session release procedure is to be applied to the 3GPP access network 210 or the Non-3GPP access network 220. Accordingly, in FIG. 2, the Access Type may be represented as a '3GPP access network'. Meanwhile, although FIG. 2 shows that the PDU session release request is triggered by the terminal 100, it may be triggered in the network AMF, SMF, and PCF.

When the AMF 310 receives the PDU session request message in step S201, the AMF 310 transmits an Nsmf_PDUSession_UpdateSMContext message to the SMF 320 through the N11 interface (S202). The Nsmf_PDUSession_UpdateSMContext message includes the PDU session release request and the Access Type received in step S201.

The SMF 320 recognizes the Access Type to be released through the Nsmf_PDUSession_UpdateSMContext message received in step S202. At this time, the SMF 320 triggers the release of the PDU session for the Access Type to be released (S203).

The SMF 320 transmits an N4 session modification request message including an Access Type to the UPF 330 (S204), and receives an N4 session modification response message from the UPF 330 in response thereto (S205). Here, the UPF 330 releases the access resource including the tunnel of the requested Access Type of the N4 session.

The SMF 320 transmits an Nsmf_PDUSession_UpdateSMContext response message to the AMF 310 through the N11 interface (S206). The Nsmf_PDUSession_UpdateSMContext response message includes an N2 SM Resource Release Request, a PDU Session Release Command, and an Access Type. Here, N2 SM resource release is to request the radio resource release of the Access Type (ie, 3GPP access network) to be released. The PDU session release command is a message that the SMF 320 intends to deliver to the terminal 100 and is carried in the N1 SM container.

The AMF 310 transmits an N2 Resource Release Request message (N2 Resource Release Request) to the access network indicated by the Access Type (ie, 3GPP access network 210) (S207). The 3GPP access network 210 receiving the N2 resource release request message in step S207 performs resource modification with the terminal 100 (S208). Here, in step S208, a PDU Session Release Command message, which is an N1 NAS message requesting a PDU session release, is transmitted to the terminal 100. The AMF 310 receives an N2 resource release amount Ack, which is a response to the N2 resource release request message, from the 3GPP access network 210 (S209).

The AMF 310 transmits an Nsmf_PDUSession_UpdateSMContext message to the SMF 320 (S210). The Nsmf_PDUSession_UpdateSMContext message includes N2 Session Management information and Access Type. Here, the N2 SM information indicates N2 resource release amount and user location information. The AMF 310 receives the Nsmf_PDUSession_UpdateSMContext response message from the SMF 320 as a response in step S210 (S211).

Meanwhile, the terminal 100 transmits a PDU session release amount (Ack) to the 3GPP access network 210 (S212). Here, step S212 is performed before the radio resource release is completely performed in step S208. That is, the steps S210 to S211 and the steps S213 to S216 to be described below are steps independently made.

The 3GPP access network 210 delivers the N1 NAS message (PDU session release amount) received from the terminal 100 in step S212 to the AMF 310 through an N2 Uplink NAS Transport message (N2 Uplink NAS Transport message). S213).

The AMF 310 transmits an Nsmf_PDUSession_UpdateSMContext message to the SMF 320 (S214). Here, the Nsmf_PDUSession_UpdateSMContext message includes N1 Session Management Information (N1 SM) and an Access Type from which radio resources are released. Here, the N1 SM information indicates the PDU session release amount and user location information.

The SMF 320 transmits an Nsmf_PDUSession_UpdateSMContext response message to the AMF 310 in response to step S215 (S215).

The SMF 320 sends an Nsmf_PDUSession_StatusNotifySMContext message including the released Access Type (eg, 3GPP Access Network 210) to the AMF 310 to inform that the access of one of the MA-PDU sessions has been released. Then, a response is received from the AMF 310 (S216).

3 is a flowchart illustrating a method of releasing a MA-PDU session according to another embodiment of the present invention.

The MA-PDU session release method of FIG. 3 relates to a method for releasing all accesses set in a MA-PDU session.

First, in FIG. 3, a UE (UE) 100 is already registered in a 5G network through a 3GPP access network 210 and a Non-3GPP access network 220, and is a MA-PDU session by various MA-PDU session creation procedures. It is assumed that the state is set (S300). The generated MA-PDU session may have the same PDU session ID (ID, identifier). In this state in which the MA-PDU session is established, the terminal 100 determines to release all of the MA-PDU sessions for a predetermined cause. Meanwhile, the network other than the terminal 100 may determine to release all of the MA-PDU sessions.

The terminal 100 transmits a PDU session release request message to the AMF 310 through one access network 210 or 220 (S301). In the following description, for convenience of explanation, it is assumed that a PDU session release request message is transmitted through the 3GPP access network 210.

The PDU Session Release Request message is an N1 NAS message and includes an Access Type and a PDU Session ID. Here, the access type means an access type to be released within the MA-PDU session. That is, in the case of FIG. 3, since all MA-PDU sessions are released, the Access Type is set to both access (ie, 3GPP access network 210 and Non-3GPP access network 220). Meanwhile, although FIG. 3 shows that the PDU session release request is triggered by the terminal 100, the PDU session release request may be triggered in the network AMF, SMF, and PCF.

When the AMF 310 receives the PDU session request message in step S301, the AMF 310 transmits an Nsmf_PDUSession_UpdateSMContext message to the SMF 320 through the N11 interface (S302). The Nsmf_PDUSession_UpdateSMContext message includes the PDU session release request (ie, N1 SM Container) received in step S301 and the Access Type.

The SMF 320 recognizes the Access Type to be released through the Nsmf_PDUSession_UpdateSMContext message received in step S302. At this time, the SMF 320 recognizes that the access request for multiple access (ie, both access) through the Access Type, and triggers PDU session release for the multiple access (S303).

The SMF 320 transmits an N4 session release request message including an Access Type to the UPF 330 (S304), and receives an N4 session release response message from the UPF 330 in response thereto (S305). Here, the UPF 330 releases all resources including the tunnel associated with the corresponding N4 session.

SMF 320 performs steps S306 and S307 described below for each access network 200.

First, the SMF 320 transmits an Nsmf_PDUSession_UpdateSMContext response message to the AMF 310 with respect to the access network (that is, the 3GPP access network 210) that has transmitted the PDU session release request message in step S301 (S306). Here, the Nsmf_PDUSession_UpdateSMContext response message includes an N2 SM Resource Release Request, a PDU Session Release Command, and an Access Type. Here, N2 SM resource release is to request the radio resource release of the Access Type to be released. The PDU session release command is a message that the SMF 320 intends to deliver to the terminal 100 and is carried in the N1 SM container.

And, for an access network (eg, Non-3GPP access network 220) that did not transmit the PDU session release request message in step S301, the SMF 320 sends a Namf_Communication_N1N2MessageTransfer message to the AMF 310 through the N11 interface. It transmits (S307). Here, the Namf_Communication_N1N2MessageTransfer message includes an N2 SM Resource Release Request and an Access Type. Here, N2 SM resource release is to request the radio resource release of the Access Type to be released.

Steps S308 to S312 described below are procedures performed after step S307, and steps S313 to S323 are steps performed after step S306. The steps S308 to S312 and the steps S313 to S323 are performed independently of each other.

In steps S308 to S312, the AMF 310 receiving the message in step S307 releases the N2 resource for the access network (that is, the Non-3GPP access network 220) that did not transmit the PDU session release request message in step S301 ( N2 Resource Release) procedure.

The AMF 310 transmits an N2 Resource Release Request message to the N3IWF 221 included in the Non-3GPP access network 220 (S308). The N3IWF 221 performs resource modification with the terminal 100 (S309). Here, in step S309, the PDU Session Release Command message, which is an N1 NAS message requesting the release of the MA-PDU session, is not transmitted to the terminal 100. The AMF 310 receives an N2 resource release amount Ack, which is a response to the N2 resource release request message, from the N3IWF 221 (S310).

The AMF 310 transmits an Nsmf_PDUSession_UpdateSMContext message to the SMF 320 (S311). The Nsmf_PDUSession_UpdateSMContext message includes N2 SM info and Access Type. Here, the N2 SM information indicates N2 resource release amount and user location information. The AMF 310 receives the Nsmf_PDUSession_UpdateSMContext response message from the SMF 320 as a response in step S311 (S312).

Steps S313 to S318 are MA-PDU session release procedures for the access network (that is, the 3GPP access network 210) to which the AMF 310 receiving the message of step S306 sent the PDU session release request message in step S301. .

The AMF 310 transmits an N2 resource release request message to the 3GPP access network 210 (S313). In step S313, the 3GPP access network 210 receiving the N2 resource release request message performs resource modification with the terminal 100 (S314). Here, in step S314, a PDU Session Release Command message, which is an N1 NAS message requesting a MA-PDU session release, is transmitted to the terminal 100. The AMF 310 receives an N2 resource release amount (Ack), which is a response to the N2 resource release request message, from the 3GPP access network 210 (S315).

The AMF 310 transmits an Nsmf_PDUSession_UpdateSMContext message to the SMF 320 (S316). The Nsmf_PDUSession_UpdateSMContext message includes N2 SM info and Access Type. Here, the N2 SM information indicates N2 resource release amount and user location information. The AMF 310 receives an Nsmf_PDUSession_UpdateSMContext response message from the SMF 320 as a response of step S316 (S317).

On the other hand, the terminal 100 transmits the PDU session release amount (Ack) to the 3GPP access network 210 (S318). Here, step S318 is performed before the radio resource release is completely performed in step S314. That is, the steps S316 to S317 and the steps S319 to S323 described below are each independently performed.

The 3GPP access network 210 delivers the N1 NAS message (PDU session release amount) received from the terminal 100 in step S318 to the AMF 310 through an N2 Uplink NAS Transport message (N2 Uplink NAS Transport) ( S319).

The AMF 310 transmits an Nsmf_PDUSession_UpdateSMContext message to the SMF 320 (S320). Here, the Nsmf_PDUSession_UpdateSMContext message includes N1 SM information (N1 SM Info, and Access Type (both access) from which radio resources are released, where the N1 SM information includes PDU Session Release Ack and user location information). Indicates.

The SMF 320 transmits an Nsmf_PDUSession_UpdateSMContext response message to the AMF 310 in response to the step S320 (S321). The SMF 320 transmits an Nsmf_PDUSession_StatusNotifySMContext message including information indicating that the release of the MA-PDU session is completed to the AMF 310 and receives a response from the AMF 310 (S322).

Step S323 is a step of deleting through the PCF 500 when a dynamic policy and charging control rule (PCC) is applied to the MA-PDU session.

Meanwhile, referring to step S309 and step S314 of FIG. 3, in step S309, a PDU session release command message is not transmitted to the terminal 100, and in step S314, a PDU session release command ) Message is transmitted to the terminal 100. That is, the N1 NAS message instructing the release of the MA-PDU session is transmitted from the network to the terminal 100 through only one access. Accordingly, the method of FIG. 3 may perform a MA-PDU session release function while minimizing signaling resources.

In the above description of FIGS. 2 and 3, although the access network used by the terminal 100 to send a N1 NAS signal message for disconnecting a MA-PDU session to the network has been described as a 3GPP access network 210 as an example, Non-3GPP The same may be applied to the access network 220.

4 illustrates a computing system in accordance with an embodiment of the present invention.

The computing system 4000 of FIG. 4 is a terminal 100, an access network 200, an AMF 310, an SMF 320, an UPF 330, a DN 400, a PCF 500, or a UDM of FIG. 1. 600 may be. Such terminal 100, access network 200, AMF 310, SMF 320, UPF 330, DN 400, PCF 500, or UDM 600 may be a computer system, for example a computer. It may be implemented in a readable medium.

The computer system 4000 may include at least one of a processor 410, a memory 430, a user interface input device 440, a user interface output device 450, and a storage device 460 that communicate over a bus 420. It may include. Computer system 4000 may also include a network interface 470 coupled to the network. The network interface 470 may transmit or receive signals with other entities over the network.

The processor 410 may be a central processing unit (CPU) or a semiconductor device that executes instructions stored in the memory 430 or the storage device 460. The processor 410 may be configured to implement the functions and methods described with reference to FIGS. 1 to 3.

The memory 430 and the storage device 460 may include various types of volatile or nonvolatile storage media. For example, the memory may include read only memory (ROM) 531 and random access memory (RAM) 432. In an embodiment of the present invention, the memory 430 may be located inside or outside the processor 410, and the memory 430 may be connected to the processor 410 through various known means.

Although the embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements of those skilled in the art using the basic concepts of the present invention defined in the following claims are also provided. It belongs to the scope of rights.

Claims (20)

A method of releasing a packet data unit (PDU) session in a network,
When a multi-access PDU session (MA-PDU session) is established, a PDU session release request message including an access type that is an access network corresponding to a session to be released by the AMF (Access and Mobility Management Function) Receiving from the terminal, and
And sending, by the AMF, a first message including the access type to a Session Management Function (SMF). The method of claim 1,
Triggering a PDU session release when the SMF receives the first message, and
And sending, by the SMF, a session modification request message including the access type to a user plane function (UPF). The method of claim 1,
The access type is any one of a 3GPP access network, a Non-3GPP access network, and both the 3GPP access network and the Non-3GPP access network. The method of claim 1,
The access type is one of a first access network and a second access network,
And the PDU session release request message is received via the first access network. The method of claim 4, wherein
The AMF further receiving a second message from the SMF in response to the first message,
The second message comprises a PDU session release command message, and the access type. The method of claim 5,
Sending, by the AMF, a third message requesting release of resources to the first access network; and
Sending, by the first access network, the PDU session release command message to the terminal. The method of claim 6,
The AMF receiving a charge message for the third message from the first access network, and
Sending, by the AMF, a fourth message including the access type to the SMF. The method of claim 6,
Receiving, by the AMF, a PDU session release amount message from the terminal;
The AMF sending a third message to the SMF that includes the access type, and
The AMF further receiving from the SMF that a PDU session corresponding to the access type has been released. The method of claim 1,
The access type is both a first access network and the second access network,
And the PDU session release request message is received via the first access network. The method of claim 9,
The AMF receiving a second message from the SMF in response to the first message, and
The AMF further receiving a third message from the SMF,
The second message includes a PDU session release command message and the access type;
The third message comprises the access type. The method of claim 10,
The AMF sending a fourth message requesting resource release to the second access network;
The AMF receiving a charge message for the fourth message from the second access network, and
The AMF further comprising sending a fifth message comprising the access type to the SMF. The method of claim 10,
The AMF sending a fourth message to the first access network requesting resource release,
Transmitting, by the first access network, the PDU session release command message to the terminal;
The AMF receiving a charge message for the fourth message from the first access network, and
Sending, by the AMF, a fourth message including the access type to the SMF. The method of claim 12,
Receiving, by the AMF, a PDU session release amount message from the terminal;
The AMF sending a fifth message including the access type to the SMF, and
The AMF further receiving from the SMF that a PDU session corresponding to the access type has been released. The method of claim 1,
And the first message is an Nsmf_PDUSession_UpdateSMContext message. The method of claim 4, wherein
Wherein the first access network and the second access network are each one of a 3GPP access network and a Non-3GPP access network. A method of releasing a packet data unit (PDU) session in a network,
When a multi-access PDU session (MA-PDU session) is established, a session management function (SMF) receiving a PDU session release request including an access type that is an access network corresponding to a session to be released during the MA-PDU session; , And
The SMF in response to the PDU session release request, performing a PDU session release. The method of claim 16,
The access type is any one of a first access network, a second access network, and both the first access network and the second access network. The method of claim 17,
Sending, by the SMF, an Nsmf_PDUSession_UpdateSMContext response message to an access and mobility management function (AMF) in response to the PDU session release request;
The Nsmf_PDUSession_UpdateSMContext Response message includes a PDU Session Release Command message, and the access type. The method of claim 18,
And sending, by the SMF, a Namf_Communication_N1N2MessageTransfer message including the access type to an Access and Mobility Management Function (AMF). A network entity that controls the release of a packet data unit (PDU) session in a network.
A processor for controlling to release the MA-PDU session when a multi-access PDU session (MA-PDU session) is established in the terminal; and
A network interface configured to receive a PDU session release request including an access type corresponding to a session to be released during the MA-PDU session;
And the processor controls to release the PDU session corresponding to the access type.

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