CN114339921B - Session migration method, session management functional entity and terminal - Google Patents

Abstract

The invention discloses a session migration method, session management functional entity and terminal, and belongs to the field of communication technology. The method includes: when it is recognized that the terminal switches from the first network to the second network, retaining the first session link and suspending sending data traffic of the second session link, where the first session link and the second session link are The session links in the first network all belong to the same multiple access protocol data unit session; the second network is used to establish a third session link, and the third session link is the connection between the terminal and the user plane functional entity in the second network session link, the user plane functional entity is a functional entity carrying multiple access protocol data unit sessions, and the user plane functional entity is located in the first network; migrate the data traffic of the second session link to the third session link. Through this method, in the event of network switching, the terminal can still carry the same session through the first session link and the third session link, retaining the multi-channel connection characteristics of the session.

Description

Session migration method, session management functional entity and terminal

Technical field

The present invention relates to the field of communication technology, and specifically relates to a session migration method, a session management functional entity and a terminal.

Background technique

The fifth generation mobile communication technology (5G) supports user terminals (User Equipment, UE) to use multi-access (Multi Access, MA) technology to establish protocol data unit (PDU) sessions, thereby achieving MA PDU session.

For example, the UE uses both 3GPP (The 3rd Generation Partnership Project) and non-3GPP methods to access the 5G network, and establishes two session links based on the two access methods. Session links implement MA PDU sessions. And, when the UE switches from the 5G network to the 4G network, the UE can choose whether to keep the MA PDU session in the 5G network. If the UE chooses to keep the MA PDU session in the 5G network, the 5G network will allocate all the data traffic of the MA PDU session to the session link corresponding to the non-3GPP access mode, and disconnect the session link corresponding to the 3GPP access mode. If the UE chooses not to keep the MA PDU session in the 5G network, the 5G network will transfer all data traffic of the MA PDU session to the session links of the 4G network and disconnect all session links in the 5G network. In other words, in the existing technology, when a terminal switches from a 5G network to another network, no matter whether the MA PDU session in the 5G network is retained, it can only retain a certain session link of the MA PDU session, and cannot maintain the MA PDU session. Multiple connection features.

Contents of the invention

To this end, the present invention provides a session migration method, a session management functional entity and a terminal to solve the problem that the terminal cannot maintain the multi-channel connection characteristics of the MA PDU when network switching occurs.

In order to achieve the above object, a first aspect of the present invention provides a session migration method. The session migration method includes:

When it is recognized that the terminal switches from the first network to the second network, the first session link is retained and the data traffic of the second session link is suspended, wherein the first session link and the second session link are The links are session links in the first network, and they all belong to the same multiple access protocol data unit session;

A third session link is established using the second network, wherein the third session link is a session link connecting the terminal and a user plane functional entity in the second network, and the user plane functional entity is A functional entity that carries the multiple access protocol data unit session, and the user plane functional entity is located in the first network;

Migrate data traffic of the second session link to the third session link.

Further, when it is recognized that the terminal switches from the first network to the second network, retaining the first session link and suspending sending data traffic of the second session link also includes:

The multi-access protocol data unit session is established based on the first access mode and the second access mode, wherein the first session link is a session link established based on the first access mode, and the third access protocol data unit session is established based on the first access mode. The second session link is a session link established based on the second access mode.

Further, the first access method is an access method based on a non-3GPP interoperability functional entity, and the second access method is an access method based on a wireless access network.

Further, using the second network to establish a third session link includes:

Establish a session tunnel between the terminal and the user plane functional entity in the first network;

Migrate the session tunnel to the second network to obtain the third session link.

Further, using the second network to establish a third session link includes:

Send first instruction information to a second network function entity, so that the second network function entity establishes the third session link in the second network according to the first instruction information, wherein the second network function entity establishes the third session link in the second network according to the first instruction information. The network functional entity is a functional entity in the second network.

Further, migrating the data traffic of the second session link to the third session link includes:

Send second instruction information to the terminal, so that the terminal uses the first network address as the source address and directs the route of the data packet sent to the user plane functional entity to the third party according to the second instruction information. Session link, obtain the first updated routing information, wherein the first network address is the network address of the terminal in the second session link;

Send third indication information to the user plane functional entity, so that the user plane functional entity points the route of the second network address to the third session link according to the third indication information, and obtains the second updated routing information. , wherein the second network address is the network address used by the user plane functional entity in the second session link;

Migrate the data traffic of the second session link to the third session link according to the first updated routing information and the second updated routing information.

Further, after migrating the data traffic of the second session link to the third session link, the method further includes:

Send fourth indication information to the access and mobility management function entity, so that the access and mobility management function entity can provide the access and mobility management function entity with the information within the validity period of the multi-access protocol data unit session according to the fourth indication information. The terminal reserves the first network address.

Further, after migrating the data traffic of the second session link to the third session link, the method further includes:

Retain the routing entry of the second session link;

When it is recognized that the terminal switches back to the first network from the second network, the routing information of the terminal and the user plane functional entity is modified according to the routing entry of the second session link, and the routing information of the terminal and the user plane functional entity is obtained. Update routing information;

According to the updated routing information, restore the data traffic of the third session link to the second session link;

Disconnect the third session link.

In order to achieve the above object, a second aspect of the present invention provides a session migration method. The session migration method includes:

In the case of switching from the first network to the second network, a session is conducted through a first session link in the first network and a third session link in the second network, wherein the first session The link is a session link in a multiple access protocol data unit session, the multiple access protocol data unit session also includes a second session link, and both the first session link and the second session link are The session link in the first network, and the data traffic of the second session link is suspended after the terminal switches from the first network to the second network, and is sent by the third session link A data link carrying the second session link.

In order to achieve the above object, the third aspect of the present invention provides a session management functional entity, which includes:

The processing module is configured to retain the first session link and suspend sending data traffic of the second session link when it is recognized that the terminal switches from the first network to the second network, wherein the first session link and the second session link are session links in the first network, and both belong to the same multiple access protocol data unit session;

An establishment module configured to establish a third session link using the second network, wherein the third session link is a session link connecting the terminal and the user plane functional entity in the second network, so The user plane functional entity is a functional entity that carries the multi-access protocol data unit session, and the user plane functional entity is located in the first network;

A migration module configured to migrate the data traffic of the second session link to the third session link.

In order to achieve the above object, a fourth aspect of the present invention provides a terminal, which includes:

a session module configured to conduct a session through a first session link in the first network and a third session link in the second network when switching from the first network to the second network, wherein , the first session link is a session link in a multiple access protocol data unit session, the multiple access protocol data unit session also includes a second session link, the first session link and the third session link Both session links are session links in the first network, and the data traffic of the second session link is suspended after the terminal switches from the first network to the second network, and is sent by The third session link carries the data link of the second session link.

The invention has the following advantages:

The session migration method, session management functional entity and terminal provided by the present invention retain the first session link and suspend sending the data traffic of the second session link when it is recognized that the terminal switches from the first network to the second network. Therefore, when a network switch occurs, part of the session links of the terminal in the first network can be retained; the second network can be used to establish a third session link, so that in addition to the session links retained in the first network, the terminal can also be used in the second network. Establish a new session link; migrate the data traffic of the second session link to the third session link. The terminal can jointly carry the same session through the first session link and the third session link, retaining the multi-path of the session. Connection characteristics.

Description of the drawings

The drawings are used to provide a further understanding of the present invention and constitute a part of the specification. They are used to explain the present invention together with the following specific embodiments, but do not constitute a limitation of the present invention.

Figure 1 is a schematic structural diagram of a conversation network provided by an embodiment of the present invention;

Figure 2 is a flow chart of a session migration method provided by an embodiment of the present invention;

Figure 3 is a flow chart of a session migration method provided by yet another embodiment of the present invention;

Figure 4 is a flow chart of a session migration method provided by yet another embodiment of the present invention;

Figure 5 is a block diagram of a session management functional entity provided by an embodiment of the present invention;

Figure 6 is a block diagram of a terminal provided by an embodiment of the present invention;

Figure 7 is a block diagram of a session migration system provided by an embodiment of the present invention;

Figure 8 is a schematic structural diagram of a session migration network provided by an embodiment of the present invention;

Figure 9 is a flow chart of a session migration method provided by an embodiment of the present application.

Detailed ways

Specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described here are only used to illustrate and explain the present invention, and are not intended to limit the present invention.

In the 5G network, terminals are allowed to connect to the 5G core network (5GCore Network, 5GC) through the wireless access network and at the same time access the 5GC through non-3GPP methods. To this end, 3GPP defines a functional entity dedicated to this access method - Non-3GPP Interworking Function (Non-3GPP Inter Working Function, N3IWF). Specifically, the UE first establishes a tunnel connection with N3IWF through any network, and then encapsulates the protocol data for interaction with 5GC in the tunnel and sends it to N3IWF. N3IWF decapsulates the protocol data received through the tunnel and forwards the protocol data to 5GC, thereby completing the interaction between UE and 5GC, allowing the terminal to access 5GC.

Figure 1 is a schematic structural diagram of a conversation network provided by an embodiment of the present application. As shown in Figure 1, the session network structure includes a terminal 101, a radio access network 102, a non-3GPP interoperability function entity 103, a user plane function entity (User Plane Function, UPF) 104, a proxy 105, a data network 106 and a server 107.

The terminal 101 accesses the agent 105 through the radio access network 102 and the non-3GPP interoperability functional entity 103, and establishes a connection with the server 107 of the data network 106 through the user plane functional entity 104 where the agent 105 is located. Among them, the wireless access network 102 corresponds to the 3GPP access method, and the non-3GPP interoperability functional entity 103 corresponds to the non-3GPP access method. The proxy 105 is a Multi-Path TCP Protocol Proxy (MPTCP Proxy), which supports the MPTCP protocol. It serves as a bridge between the client and the server, allowing the client to use 3GPP access methods and non-3GPP access methods at the same time. server to interact. In practical applications, the agent 105 may be a proxy server or agent software, which is not limited in this application.

For the terminal 101, it can access the data network through the session link corresponding to the wireless access network 102-agent 105 (or user plane functional entity 104)-server 107, or it can also access the data network through the non-3GPP interoperability functional entity 103-agent. 105 (or user plane functional entity 104)—the session link corresponding to the server 107 accesses the data network. The above two session links constitute an MA PDU session.

It should be noted that the 5G network provides Access Traffic Steering, Switching and Splitting (ATSSS) technology to allocate the data flow of each session link in the MA PDU session. Currently, ATSSS technology provides four working modes:

Hot standby mode (Active-Standby): When the primary access method is unavailable, the data flow is automatically switched to the backup access method. The characteristic is that the two access methods do not carry data flows at the same time.

Smallest Delay mode: Automatically switches the data flow to an access method with a relatively small transmission delay. The characteristic is that the two access methods do not carry data flows at the same time.

Load-Balancing mode (Load-Balancing): Allocates data flows between two access methods according to a preset distribution ratio.

Priority-based mode: By default, the data flow is carried on the access method with higher priority. When congestion is detected in the high-priority access method, some data flows are switched to the low-priority access method.

A first aspect of this application provides a session migration method. Figure 2 is a flow chart of a session migration method provided by an embodiment of the present application. The session migration method can be applied to session management functional entities. As shown in Figure 2, the session migration method includes the following steps:

Step S201: When it is recognized that the terminal switches from the first network to the second network, the first session link is retained and data traffic of the second session link is suspended.

The first session link and the second session link are session links in the first network, and both belong to the same multiple access protocol data unit session.

In some embodiments, the terminal establishes a multi-access protocol data unit session in the first network, and the multi-access protocol data unit session includes two session links, namely a first session link and a second session link. The first network may be a 5G network, the second network may be a 4G network, the first session link corresponds to an access method based on the non-3GPP interoperability function entity N3IWF, and the second session link corresponds to an access method based on the wireless access network. entry method. When the session management function entity (Session Management Function, SMF) recognizes that the terminal switches from the first network to the second network (the session management function entity is located in the first network), the first session link is retained and the second session link is suspended. Data traffic on the session link.

It should be noted that since the first session link corresponds to the non-3GPP interoperability function entity access mode, even if the terminal switches to the second network, the first session link is still retained. In practical applications, the operation of retaining the first session link and suspending the transmission of data traffic of the second session link can be achieved by using the retain MA PDU session command.

It should also be noted that there should be an interoperability relationship between the first network and the second network. Based on this, the session migration method provided by the embodiment of the present application can be implemented. In other words, if the first network and the second network are independent of each other, the session migration method cannot be implemented. For example, if the first communication operator and the second communication operator do not reach a cooperation agreement in advance, and the terminal switches between the networks of the first communication operator and the second communication operator, the session migration method cannot be implemented.

Step S202: Establish a third session link using the second network.

The third session link is a session link connecting the terminal and the user plane functional entity in the second network. The user plane functional entity is a functional entity that carries multiple access protocol data unit sessions, and the user plane functional entity is located in the first network. .

It should be noted that using the second network to establish the third session link mainly includes two methods: the first method is to establish a session tunnel in the first network, and then migrate the session tunnel to the second network; the second method The method is to directly establish a session tunnel in the second network and use the session tunnel as the third session link.

In some embodiments, the session management functional entity establishes a session tunnel between the terminal and the user plane functional entity in the first network, and migrates the session tunnel to the second network to obtain a third session link.

In some other embodiments, the session management function entity sends the first indication information to the second network function entity, and the second network function entity receives the first indication information, and establishes the session tunnel in the second network according to the first indication information as the second network function entity. Three session links. Wherein, the second network functional entity is a functional entity in the second network.

Step S203: Migrate the data traffic of the second session link to the third session link.

Since the data traffic of the second session link is migrated to the third session link, the data flow of the original second session link can be carried by the third session link. Based on this, the first session link and the third session link reconstitute a multiple access protocol data unit session.

In some embodiments, the session management function entity first sends second instruction information to the terminal, so that the terminal uses the first network address as the source address to route the data packet sent to the user plane function entity according to the second instruction information. Point to the third session link to obtain the first updated routing information, where the first network address is the network address of the terminal in the second session link; secondly, the session management functional entity sends third indication information to the user plane functional entity, The user plane functional entity directs the route of the second network address to the third session link according to the third instruction information to obtain the second updated routing information, where the second network address is the user plane functional entity in the second session link. The network address used; finally, the session management function entity migrates the data traffic of the second session link to the third session link based on the first updated routing information and the second updated routing information.

In this embodiment, when it is recognized that the terminal switches from the first network to the second network, the first session link is retained and the data traffic of the second session link is suspended, so that the terminal can be retained when network switching occurs. Part of the session link in the first network; using the second network to establish a third session link, so that the terminal establishes a new session link in the second network in addition to the session link retained in the first network; The data traffic of the second session link is migrated to the third session link, and the terminal can jointly carry the same session through the first session link and the third session link, retaining the multi-channel connection characteristics of the session.

It should be noted that in some embodiments, the second network is used to establish the third session link, which specifically includes two situations: In the first situation, there is an interface (for example, N26) between the first network and the second network. interface); in the second case, there is no interface between the first network and the second network. Whether there is an interface between the first network and the second network can be sent to the terminal by an Access and Mobility Management Function (AMF).

For the first situation, there are at least two specific implementations. In a first specific implementation manner, there is an interface between the first network and the second network, and the session management function entity communicates to the Packet Data Network Gateway control plane (PGW-C) function entity in the second network. ) or the SMF+PGW-C (or PGW-C+SMF) dedicated to the interoperation between the first network and the second network sends a notification (ie, the first indication information), so that the PGW-C or SMF+ in the second network PGW-C establishes a session tunnel between the terminal and the UPF (or MPTCP proxy in UPF) carrying the MA PDU session, thereby obtaining the third session link. In the second specific implementation, there is no interface between the first network and the second network. The session management function entity initiates and establishes a session tunnel between the terminal and the UPF in the first network, and then instructs the PGW-C (or PGW-C+SMF) migrates the session tunnel to the second network to obtain the third session link.

For the second situation, there is at least one specific implementation. Specifically, the session management function entity establishes a session tunnel between the terminal and the UPF in the first network, and then instructs the terminal to migrate the session tunnel to the second network to obtain a third session link.

It should also be noted that in some embodiments, after migrating the data traffic of the second session link to the third session link, it also includes:

Send fourth indication information to the access and mobility management functional entity, so that the access and mobility management functional entity reserves the first network address for the terminal within the validity period of the multi-access protocol data unit session according to the fourth indication information. Wherein, the access and mobility management functional entity is located in the first network.

Figure 3 is a flow chart of a session migration method provided by yet another embodiment of the present application. The session migration method can be applied to session management functional entities. As shown in Figure 3, the session migration method includes the following steps:

Step S301: Establish a multi-access protocol data unit session based on the first access mode and the second access mode.

The first session link is a session link established based on the first access method, and the second session link is a session link established based on the second access method.

In some embodiments, the first access method is an access method based on a non-3GPP interoperability functional entity; the second access method is an access method based on a wireless access network. Among them, access methods based on wireless access networks include access technologies proposed by the 3GPP organization, such as Time Division-Synchronous Code Division Multiple Access (TD-SCDMA) technology, wideband code division multiple access (Wideband Code Division Multiple Access, WCDMA) technology; access methods based on non-3GPP interoperability functional entities refer to access technologies proposed by organizations other than 3GPP, such as Code Division Multiple Access (CDMA) )technology.

Step S302: When it is recognized that the terminal switches from the first network to the second network, the first session link is retained and data traffic of the second session link is suspended.

Step S303: Use the second network to establish a third session link.

Step S304: Migrate the data traffic of the second session link to the third session link.

Steps S302 to S304 in this embodiment are the same as steps S201 to S203 in the previous embodiment of this application, and will not be described again.

Step S305: Reserve the routing entry of the second session link.

In this embodiment of the present application, after the terminal switches from the first network to the second network, the data traffic of the second session link is suspended, but the second session link is not disconnected. Specifically, due to network switching, the second session link itself cannot communicate normally, but the resources of the second session link (routing resources, network address resources, etc.) have not been recycled, and its routing entries are still retained so that when the network When switching back to the first network, the transmission of data traffic on the second session link can be resumed conveniently and quickly.

Step S306: When it is recognized that the terminal switches back to the first network from the second network, the routing information of the terminal and the user plane functional entity is modified according to the routing entry of the second session link to obtain updated routing information.

Step S307: According to the updated routing information, restore the data traffic of the third session link to the second session link.

The data traffic of the third session link is the data traffic obtained by migrating the data traffic of the original second session link. When the terminal switches back to the first network from the second network, the session management functional entity transfers the third session link The data traffic of the session link is restored to the second session link. Based on this, the first session link and the second session link constitute a multiple access protocol data unit session.

It should be noted that the method of restoring the data traffic of the third session link to the second session link is the same as the method of migrating the data traffic of the second session link to the third session link, and will not be described again here. .

Step S308: Disconnect the third session link.

In this embodiment, a multi-access protocol data unit session is established based on the first access mode and the second access mode. When it is recognized that the terminal switches from the first network to the second network, the first session link is retained. , suspend sending the data traffic of the second session link, use the second network to establish a third session link, migrate the data traffic of the second session link to the third session link, and after identifying that the terminal switches back from the second network In the case of the first network, the data traffic of the third session link is restored to the second session link, and the third session link is disconnected. Based on this, after the terminal switches back to the first network, the data traffic of the third session link is restored to the second session link, and the third session link is disconnected, so that based on the first session link and the second session link The multi-access protocol data unit session before the path is restored ensures that the multi-path connection characteristics of the MA PDU session are still maintained in the event of network switching.

Figure 4 is a flow chart of a session migration method provided by yet another embodiment of the present application. The session migration method can be applied to terminals. As shown in Figure 4, the session migration method includes the following steps:

Step S401: When switching from the first network to the second network, conduct a session through the first session link in the first network and the third session link in the second network.

Wherein, the first session link is a session link in a multiple access protocol data unit session, the multiple access protocol data unit session also includes a second session link, and the first session link and the second session link are both A session link in one network, and the data traffic of the second session link is suspended after the terminal switches from the first network to the second network, and the third session link carries the data link of the second session link.

In some embodiments, the terminal accesses the first network through the first access method and the second access method respectively. The session management function entity in the first network establishes a multi-access protocol data unit session based on the first access mode and the second access mode, and retains the first access protocol data unit session when identifying that the terminal switches from the first network to the second network. The session link suspends sending the data traffic of the second session link, uses the second network to establish a third session link, and migrates the data traffic of the second session link to the third session link. Based on this, the terminal establishes a session connection in the first network through the first session link, and establishes a session connection in the second network through the second session link, retaining the multi-channel connection characteristics of the MA PDU session.

In this embodiment, after the terminal switches from the first network to the second network, the first session link in the MA PDU session is retained, the data traffic of the second session link is suspended, and the third session link is established in the second network. Three session links: Build an MA PDU session based on the first session link and the third session link, thereby maintaining the multi-channel connection characteristics of the MA PDU session.

The steps of the various methods above are divided just for the purpose of clear description. During implementation, they can be combined into one step or some steps can be split into multiple steps. As long as they include the same logical relationship, they are all within the scope of protection of this patent. ; Adding insignificant modifications or introducing insignificant designs to the algorithm or process without changing the core design of the algorithm and process are within the scope of protection of this patent.

The second aspect of this application provides a session management functional entity. Figure 5 is a block diagram of a session management functional entity provided by an embodiment of the present application. As shown in Figure 5, the session management function entity 500 includes:

The processing module 501 is configured to retain the first session link and suspend sending data traffic of the second session link when it is recognized that the terminal switches from the first network to the second network.

The first session link and the second session link are session links in the first network, and both belong to the same multiple access protocol data unit session.

The establishment module 502 is configured to establish a third session link using the second network.

The third session link is a session link connecting the terminal and the user plane functional entity in the second network. The user plane functional entity is a functional entity that carries multiple access protocol data unit sessions, and the user plane functional entity is located in the first network. .

The migration module 503 is configured to migrate the data traffic of the second session link to the third session link.

In this embodiment, when the processing module recognizes that the terminal switches from the first network to the second network, it retains the first session link, suspends sending the data traffic of the second session link, and the establishment module uses the second network to establish the third session link, and migrates the data traffic of the second session link to the third session link through the migration module. Based on this, even if a network switch occurs, the terminal can still jointly carry the same session through the first session link and the third session link, thereby retaining the multi-channel connection characteristics of the session.

A third aspect of this application provides a terminal. Figure 6 is a block diagram of a terminal provided by an embodiment of the present application. As shown in Figure 6, the terminal 600 includes:

The session module 601 is configured to conduct a session through the first session link in the first network and the third session link in the second network when switching from the first network to the second network.

Wherein, the first session link is a session link in a multiple access protocol data unit session, the multiple access protocol data unit session also includes a second session link, and the first session link and the second session link are both A session link in one network, and the data traffic of the second session link is suspended after the terminal switches from the first network to the second network, and the data link of the second session link is carried by the third session link .

In this embodiment, after the terminal switches from the first network to the second network, it retains the first session link in the MA PDU session, suspends sending data traffic of the second session link, and establishes a third session link in the second network. session link, and the session module conducts the session through the first session link in the first network and the third session link in the second network, thereby maintaining the multi-channel connection characteristics of the MA PDU session.

The third aspect of this application provides a session migration system. Figure 7 is a schematic diagram of the composition of a session migration system provided by an embodiment of the present application. As shown in Figure 7, the session migration system 700 includes: a first network 701, a terminal 702 and a second network 703.

After the terminal accesses the first network through two access methods, the MA PDU session is established, and the MA PDU session includes a first session link and a second session link. After the terminal switches from the first network to the second network, it suspends sending data traffic of the second session link and maintains the first session link. Furthermore, the first network establishes a third session link in the second network through its session management functional entity, and migrates the data traffic of the second session link to the third session link, thereby based on the first session link and the third session link. The session link reconstructs the MA PDU session. Based on this, the terminal retains the first session link in the first network and the third session link in the second network, thereby maintaining the multi-channel connection characteristics of the MA PDU session.

Figure 8 is a schematic diagram of a session migration network structure provided by an embodiment of the present application. As shown in Figure 8, the session migration network structure 800 includes: terminal 801, second radio access network 802, packet data gateway 803, first radio access network 804, non-3GPP interoperability functional entity 805, user plane functional entity 806, proxy 807, data network 808 and server 809.

In some embodiments, the terminal 801 establishes a first session link with the agent 807 in the user plane functional entity 806 through the non-3GPP interoperability functional entity 805 based on WIFI. At the same time, the terminal 801 communicates with the user through the first wireless access network 804. The agent 807 in the surface function entity 806 establishes a second session link, thereby constructing a MA PDU session in the first network. The user plane functional entity 806 establishes a connection with the server 809 in the data network 808. Among them, the first wireless access network 804 is an access network corresponding to the first network.

After the terminal 801 switches from the first network to the second network, the session management function entity (not shown in the figure) in the first network maintains the first session link, suspends sending the data traffic of the second session link, and based on The second radio access network 802 and the packet data gateway 803 establish a third session link in the second network. Among them, the packet data gateway 803 is connected to the user plane functional entity 806, and the second radio access network 802 is the access network corresponding to the second network.

Based on this, the terminal 801 maintains a session connection with the server 809 in the first network through the first session link, and maintains a session connection with the server 809 in the second network through the third session link, thereby maintaining the multi-channel connection of the MA PDU session. characteristic.

Figure 9 is a flow chart of a session migration method provided by an embodiment of the present application. As shown in Figure 9, the session migration method includes:

Step S901: The terminal establishes a MA PDU session in the first network based on the MPTCP protocol.

Among them, the MA PDU session includes a first session link and a second session link. The first session link is a session link established based on the non-3GPP interoperability function entity access method, and the second session link is based on wireless access. Session link established through network access.

Step S902: The terminal switches from the first network to the second network.

Among them, the reasons for network switching in the terminal include network coverage signal range, network coverage signal strength, and certain specific services triggering network switching.

Step S903: When the session management function entity in the first network recognizes that the terminal switches from the first network to the second network, it retains the first session link and suspends sending data traffic of the second session link.

Step S904: The session management function entity establishes a session tunnel in the first network.

Wherein, the session tunnel connects the terminal and the user plane functional entity, and the user plane functional entity is the functional entity that carries the MA PDU session in the first network.

Step S905: The session management function entity migrates the session tunnel to the second network and uses the session tunnel as the third session link.

Step S906: The session management function entity migrates the data traffic of the second session link to the third session link.

Based on this, the first session link and the third session link constitute an MA PDU session, ensuring the multi-channel connection characteristics of the MA PDU session.

It should be noted that, in some embodiments, after step S906, the session management function entity instructs the AMF to retain the network address of the terminal in the third session link (or the second session link) during the MA PDU session. When the terminal switches back to the first network from the second network, the session management function entity instructs the AMF not to allocate a new network address for the 3GPP access mode to the terminal, and restores the data traffic of the third session link to the second session link. path (using the network address of the terminal and UPF in the second session link), and disconnect the third session link.

It is worth mentioning that each module involved in this implementation is a logical module. In practical applications, a logical unit can be a physical unit, or a part of a physical unit, or it can be multiple physical units. The combination of units is realized. In addition, in order to highlight the innovative part of the present invention, units that are not closely related to solving the technical problems raised by the present invention are not introduced in this embodiment, but this does not mean that other units do not exist in this embodiment.

It can be understood that the above embodiments are only exemplary embodiments adopted to illustrate the principles of the present invention, but the present invention is not limited thereto. For those of ordinary skill in the art, various modifications and improvements can be made without departing from the spirit and essence of the present invention, and these modifications and improvements are also regarded as the protection scope of the present invention.

Claims (10)

1. A method for session migration, comprising:

under the condition that the terminal is identified to be switched from a first network to a second network, a first session link is reserved, and data traffic of a second session link is suspended, wherein the first session link and the second session link are session links in the first network and all belong to the same multi-access protocol data unit session, the first session link is a session link established based on a first access mode, and the second session link is a session link established based on a second access mode;

establishing a third session link by using the second network, wherein the third session link is a session link in the second network for connecting the terminal and a user plane functional entity, the user plane functional entity is a functional entity for bearing the multi-access protocol data unit session, and the user plane functional entity is located in the first network;

and migrating the data traffic of the second session link to the third session link.

2. The session migration method according to claim 1, wherein in the case that the terminal is identified to be handed over from the first network to the second network, the first session link is reserved, and before the data traffic of the second session link is suspended, the method further comprises:

the multi-access protocol data unit session is established based on the first access mode and the second access mode, wherein the first access mode is an access mode based on a non-3GPP interoperable functional entity, and the second access mode is an access mode based on a wireless access network.

3. The session migration method of claim 1, wherein the establishing a third session link using the second network comprises:

establishing a session tunnel between the terminal and the user plane functional entity in the first network;

and migrating the session tunnel to the second network to obtain the third session link.

4. The session migration method of claim 1, wherein the establishing a third session link using the second network comprises:

and sending first indication information to a second network functional entity so that the second network functional entity can establish the third session link in the second network according to the first indication information, wherein the second network functional entity is a functional entity in the second network.

5. The session migration method according to claim 1, wherein said migrating data traffic of the second session link to the third session link comprises:

sending second indication information to the terminal so that the terminal directs the route of a data packet which takes a first network address as a source address and is sent to the user plane functional entity to the third session link according to the second indication information to obtain first updated route information, wherein the first network address is a network address of the terminal in the second session link;

transmitting third indication information to the user plane functional entity so that the user plane functional entity directs a route of a second network address to the third session link according to the third indication information to obtain second updated route information, wherein the second network address is a network address used by the user plane functional entity in the second session link;

and migrating the data traffic of the second session link to the third session link according to the first updated routing information and the second updated routing information.

6. The session migration method of claim 5, wherein after migrating the data traffic of the second session link to the third session link, further comprising:

and sending fourth indication information to an access and mobility management functional entity, so that the access and mobility management functional entity reserves the first network address for the terminal in the validity period of the multi-access protocol data unit session according to the fourth indication information.

7. The session migration method according to claim 1, wherein after migrating the data traffic of the second session link to the third session link, further comprising:

reserving a routing entry for the second session link;

under the condition that the terminal is identified to be switched back to the first network from the second network, the routing information of the terminal and the user plane functional entity is modified according to the routing entry of the second session link, and updated routing information is obtained;

restoring the data flow of the third session link to the second session link according to the updated routing information;

and disconnecting the third session link.

8. A method for session migration, comprising:

in the case of switching from a first network to a second network, a session is performed through a first session link in the first network and a third session link in the second network, wherein the first session link is a session link in a multi-access protocol data unit session, the multi-access protocol data unit session further comprises a second session link, the first session link and the second session link are both session links in the first network, data traffic of the second session link is suspended to be sent after a terminal is switched from the first network to the second network, and the third session link carries data links of the second session link, the first session link is a session link established based on a first access mode, and the second session link is a session link established based on a second access mode.

9. A session management functional entity, comprising:

the processing module is configured to reserve a first session link and suspend sending data traffic of a second session link under the condition that the terminal is identified to be switched from a first network to a second network, wherein the first session link and the second session link are session links in the first network and all belong to the same multi-access protocol data unit session, the first session link is a session link established based on a first access mode, and the second session link is a session link established based on a second access mode;

the establishing module is configured to establish a third session link by using the second network, wherein the third session link is a session link in the second network for connecting the terminal and a user plane functional entity, the user plane functional entity is a functional entity for bearing the multi-access protocol data unit session, and the user plane functional entity is located in the first network;

and the migration module is configured to migrate the data traffic of the second session link to the third session link.

10. A terminal, comprising:

and a session module configured to perform a session through a first session link in a first network and a third session link in a second network in case of switching from the first network to the second network, wherein the first session link is a session link in a multi-access protocol data unit session, the multi-access protocol data unit session further comprises a second session link, the first session link and the second session link are both session links in the first network, and data traffic of the second session link is suspended to be sent after a terminal is switched from the first network to the second network, and the third session link carries data links of the second session link, the first session link is a session link established based on a first access mode, and the second session link is a session link established based on a second access mode.