CN108934007B

CN108934007B - Policy control method for UPF reselection, PCF and SMF

Info

Publication number: CN108934007B
Application number: CN201710377964.1A
Authority: CN
Inventors: 周晓云; 朱进国
Original assignee: ZTE Corp
Current assignee: ZTE Corp
Priority date: 2017-05-25
Filing date: 2017-05-25
Publication date: 2022-03-25
Anticipated expiration: 2037-05-25
Also published as: CN108934007A; WO2018214638A1

Abstract

The embodiment of the invention discloses a policy control method for UPF reselection, PCF and SMF, wherein the method comprises the following steps: acquiring an anchor point reselection event of a first PDU session, a validity period of a first IP address of UE corresponding to a first UPF and a second IP address of UE corresponding to a second UPF from an SMF; and sending the validity period of the first IP address and the second IP address to AF corresponding to each target application.

Description

Policy control method for UPF reselection, PCF and SMF

Technical Field

The invention relates to a mobile communication technology, in particular to a policy control method for user plane function entity UPF reselection, a policy control function entity PCF and a session management function entity SMF.

Background

Currently, the industry is researching the next generation wireless communication system, i.e. the fifth generation mobile communication technology (5th-generation, abbreviated as 5G). Fig. 1 is a schematic structural diagram of a conventional 5G network based on a single protocol data unit PDU session. As shown in fig. 1, the 5G network includes the following functions: a connection management function: the method mainly takes charge of air interface resource scheduling and air interface connection management of the terminal access network; the authentication service function: the method mainly takes charge of authenticating and authorizing the access of User Equipment (UE); unified Data Manager (UDM) function: the method mainly takes charge of storing the subscription data of the user; access and Mobility Management Function (AMF): the mobile terminal is mainly responsible for access authentication, authorization and mobility management; a Session Management Function (SMF) mainly responsible for Session Management and IP address allocation; the User Plane Function (UPF) is mainly responsible for routing and forwarding Protocol Data Units (PDUs), and performing policies on packet Data. A Policy Control Function (PCF), which is mainly responsible for Policy decision; the Application Function (AF) is mainly responsible for providing service information of a user access service to the PCF, and is used for policy decision of the PCF.

In addition, three modes of Session and Service Continuity (SSC) are defined in the 5G network: 1) mode (Mode) 1: the UPF remains unchanged regardless of changes in the access network used by the UE; 2) mode 2: when the UE does not leave the service area of the UPF, the UPF is kept unchanged; when the UE leaves the service area of the UPF, a different UPF, appropriate for the UE's current access network attachment point, will be used to serve the UE; 3) mode 3: the UE is allowed to establish a PDU session to the same data network before the first PDU session terminates and the network selects a second UPF suitable for the UE. At this time, the UE may release the first UPF after migrating the application from the first UPF to the second UPF; or the UE releases the first UPF after waiting for the application bound on the first UPF to end.

Fig. 2 is a schematic structural diagram of a conventional Multi-Homed PDU session based 5G network. As shown in fig. 2, when the UE moves, the network introduces a branch point (Branching point) in the user plane link of the UE and allocates a new UPF, i.e. a second user plane functional entity (second UPF), and the network also allocates another IP address to the UE. In the uplink direction, the forking point forwards the data of the new IP address adopted by the UE to the second user plane functional entity (second UPF), and the data of the old IP address still forwards to the first user plane functional entity (first UPF). In the downlink direction, the bifurcation point converges data from the first user plane functional entity (first UPF) and the second user plane functional entity (second UPF) and forwards the converged data to the base station. In actual deployment, the bifurcation point may be integrated with the second user plane functional entity 2 (second UPF).

Fig. 3 is a schematic flow chart of an implementation of a policy control method for UPF reselection in the prior art. As shown in fig. 3, the policy control method for UPF reselection may include the following steps:

step 301, a first PDU session is established between the UE and the first UPF.

And step 302, when the SMF meets the preset triggering condition, the SMF executes a Multi-Homed decision.

Step 303, the SMF sends a NAS message notification to the UE.

In this step, the SMF informs the UE that the first PDU session is to be released after a period of Time (Time1), and at the same Time, the SMF informs the UE to request to establish a second PDU session to the same external data network dn (data network).

Step 304, the UE sends a message to the SMF to establish a second PDU session with a second UPF.

Step 305, releasing the first PDU session between the UE and the first UPF.

In the process of implementing the invention, the inventor finds that at least the following problems exist in the prior art:

in the existing policy control method for reselecting the UPF, the SMF determines whether to reselect the UPF, and although when the SMF satisfies a preset trigger condition, the SMF may reselect a third-party application from a first UPF to a second UPF according to a request of the third-party application, since the SMF can only perform the UPF reselection for one of the target applications, the SMF has no way to reselect the target application from the first UPF to the second UPF for other target applications that the UE is accessing, which may affect the use experience of the other target applications that the UE is accessing.

Disclosure of Invention

In order to solve the existing technical problem, embodiments of the present invention desirably provide a policy control method for UPF reselection, a PCF, and an SMF, so that after one target application triggers UPF reselection, the UE is notified of an event of the UPF reselection to another target application being visited by the UE, so that the another target application performs application layer reselection within the validity period of the first IP address, and the use experience of the another target application being visited by the UE is not affected.

In order to achieve the above purpose, the technical solution of the embodiment of the present invention is realized as follows:

the embodiment of the invention provides a policy control method for UPF reselection, which comprises the following steps:

acquiring an event notification of anchor point reselection of a first PDU session from the SMF, a validity period of a first IP address of User Equipment (UE) corresponding to a first UPF and a second IP address of the UE corresponding to a second UPF;

and sending the validity period of the first IP address and the second IP address to AF corresponding to each target application.

In the above embodiment, before the obtaining, from the SMF, the event notification of anchor point reselection occurring in the first PDU session, the validity period of the first IP address of the UE corresponding to the first UPF, and the second IP address of the UE corresponding to the second UPF, the method further includes:

and acquiring the first IP address from the SMF in the establishment process of the first PDU session.

receiving first service information corresponding to each target application provided by each AF;

formulating a first strategy rule corresponding to each target application according to the first service information corresponding to each target application;

and providing the strategy rules corresponding to the target applications to the SMF.

In the above embodiment, after the sending the validity period of the first IP address and the second IP address to the AF corresponding to each target application, the method further includes:

receiving second service information corresponding to each target application provided by each AF;

formulating a second strategy rule corresponding to each target application according to second service information corresponding to each target application;

and providing the second policy rules corresponding to the target applications to the SMF.

receiving addresses of target application servers corresponding to the target applications provided by the AF;

and providing the address of the target application server corresponding to each target application to the SMF.

The embodiment of the invention also provides a policy control method for UPF reselection, which comprises the following steps:

when a preset trigger condition is met, executing anchor point reselection on the first PDU session;

and notifying the PCF of the event notification of the anchor point reselection, the validity period of the first IP address of the UE corresponding to the first UPF and the second IP address of the UE corresponding to the second UPF.

In the above embodiment, before the performing anchor point reselection on the first PDU session, the method further comprises:

in the process of establishing the first PDU session, selecting the first UPF for the first PDU session, and distributing the first IP address;

notifying the PCF of the first IP address.

In the above embodiment, the trigger condition includes at least one of:

receiving a flow guide request sent by any one target application;

or the network load of the first UPF exceeds a preset threshold value;

or receiving the report of the user plane detection information sent by the first UPF.

In the above embodiment, after the performing anchor reselection on the first UPF, the method further comprises:

changing the first UPF session into a Multi-Homing PDU session;

selecting the second UPF for the Multi-Homing PDU session and assigning the second IP address.

In the above embodiment, after the performing anchor point reselection on the first PDU session, the method further comprises:

informing the UE that the first PDU session is to be released after the validity period so that the UE requests to establish a second PDU session; wherein the first PDU session is the same as the external data network DN corresponding to the second PDU session;

and receiving a request message for establishing the second PDU session sent by the UE, selecting the second UPF for the second PDU session, and allocating the second IP address.

receiving a first policy rule corresponding to each target application formulated by the PCF;

formulating a first packet detection rule corresponding to each target application according to a first strategy rule corresponding to each target application;

and providing the first packet detection rule corresponding to each target application to the second UPF.

In the foregoing embodiment, after notifying the PCF of the event notification of anchor reselection occurring, the validity period of the first IP address of the UE corresponding to the first UPF, and the second IP address of the UE corresponding to the second UPF, the method further includes:

receiving a second policy rule corresponding to each target application formulated by the PCF;

formulating a second grouping detection rule corresponding to each target application according to a second strategy rule corresponding to each target application;

providing the second UPF with a corresponding packet detection rule for each target application.

receiving addresses of source application servers corresponding to the target applications provided by the PCF;

and providing the address of the source application server corresponding to each target application to the UE.

In the foregoing embodiment, after notifying the PCF of the event notification of anchor point reselection occurring, the validity period of the first IP address of the UE corresponding to the first UPF, and the second IP address of the UE corresponding to the second UPF, the method further includes:

receiving addresses of target application servers corresponding to the target applications provided by the PCF;

and providing the addresses of the target application servers corresponding to the target applications to the UE.

An embodiment of the present invention further provides a PCF, where the PCF includes: an acquisition unit and a transmission unit; wherein,

the acquiring unit is used for acquiring an event notification of anchor point reselection of a first PDU session from the SMF, a validity period of a first IP address of the UE corresponding to the first UPF and a second IP address of the UE corresponding to the second UPF;

and sending the first IP address, the validity period and the second IP address to AF corresponding to each target application.

In the foregoing embodiment, the obtaining unit is further configured to obtain the first IP address from the SMF in the process of establishing the first PDU session.

In the above embodiment, the PCF further comprises: the system comprises a policy rule making unit, a policy rule setting unit and a service processing unit, wherein the policy rule making unit is used for receiving first service information which is provided by each AF and corresponds to each target application; formulating a first strategy rule corresponding to each target application according to the first service information corresponding to each target application;

the sending unit is further configured to provide the policy rules corresponding to the respective target applications to the SMF.

In the above embodiment, the policy rule making unit is further configured to receive second service information corresponding to each target application provided by each AF; formulating a second strategy rule corresponding to each target application according to second service information corresponding to each target application;

the sending unit is further configured to provide the second policy rule corresponding to each target application to the SMF.

In the above embodiment, the obtaining unit is further configured to receive an address of a target application server corresponding to each target application provided by each AF;

the sending unit is further configured to provide the SMF with addresses of target application servers corresponding to the target applications.

An embodiment of the present invention further provides an SMF, where the SMF includes: an anchor point reselection unit and a notification unit; wherein,

the anchor point reselection unit is used for executing anchor point reselection to the first PDU session when a preset trigger condition is met;

the notification unit is configured to notify the PCF of an event notification of anchor reselection occurring, a validity period of a first IP address of the UE corresponding to the first UPF, and a second IP address of the UE corresponding to the second UPF.

In the above embodiment, the SMF further includes: an address allocation unit, configured to select the first UPF for the first PDU session in the process of establishing the first PDU session, and allocate the first IP address;

the notifying unit is further configured to notify the PCF of the first IP address.

In the above embodiment, the trigger condition includes at least one of:

receiving a flow guide request sent by any one target application;

or the network load of the first UPF exceeds a preset threshold value;

In the above embodiment, the address allocating unit is further configured to change the first UPF session to a Multi-Homing PDU session; selecting the second UPF for the Multi-Homing PDU session and assigning the second IP address.

In the above embodiment, the notifying unit is further configured to notify the UE that the first PDU session is to be released after the validity period, so that the UE requests to establish a second PDU session; wherein the first PDU session is the same as the external data network DN corresponding to the second PDU session;

the address allocation unit is further configured to receive a request message for establishing the second PDU session sent by the UE, select the second UPF for the second PDU session, and allocate the second IP address.

In the above embodiment, the SMF further includes: a detection rule making unit, configured to receive a first policy rule corresponding to each target application made by the PCF; formulating a first packet detection rule corresponding to each target application according to a first strategy rule corresponding to each target application;

the notification unit is further configured to provide the first packet detection rule corresponding to each target application to the second UPF.

In the above embodiment, the detection rule making unit is further configured to receive a second policy rule corresponding to each target application made by the PCF; formulating a second grouping detection rule corresponding to each target application according to a second strategy rule corresponding to each target application;

the notifying unit is further configured to provide the second UPF with the packet detection rule corresponding to each target application.

In the foregoing embodiment, the anchor point reselection unit is further configured to receive addresses of source application servers corresponding to the target applications, where the addresses are provided by the PCF;

the notification unit is further configured to provide the address of the source application server corresponding to each target application to the UE.

In the above embodiment, the anchor point reselection unit is further configured to receive addresses of target application servers corresponding to the target applications, where the addresses are provided by the PCF;

the notification unit is further configured to provide the address of the target application server corresponding to each target application to the UE.

Therefore, in the technical solution of the embodiment of the present invention, the PCF may first obtain, from the SMF, an event notification that anchor reselection occurs to the first PDU session, a validity period of the first IP address of the UE corresponding to the first UPF, and a second IP address of the UE corresponding to the second UPF; the PCF may then send the validity period of the first IP address and the second IP address to AFs corresponding to respective target applications. That is to say, in the technical solution of the embodiment of the present invention, the PCF may notify the validity period of the IP address corresponding to the first UPF and the IP address of the second UPF to the AF corresponding to each target application, so that each target application may perform application layer reselection before the validity period of the first IP address, that is, perform service access by using the second IP address, and each target application may select an application server closer to the second UPF to continue providing services. In the prior art, the SMF can only perform UPF reselection for one of the target applications. Therefore, compared with the prior art, the policy control method for UPF reselection, PCF, and SMF provided in the embodiments of the present invention can notify other target applications that the UE is accessing to an event for UPF reselection after one target application triggers UPF reselection, so that the other target applications perform application layer reselection within the validity period of the first IP address, and do not affect the use experience of the other target applications that the UE is accessing; in addition, the technical scheme of the embodiment of the invention is simple and convenient to realize, convenient to popularize and wider in application range.

Drawings

FIG. 1 is a schematic diagram of a structure of a conventional single PDU session based 5G network;

FIG. 2 is a schematic diagram of a structure of a conventional multi-homing PDU session-based 5G network;

fig. 3 is a schematic flow chart illustrating an implementation of a policy control method for UPF reselection in the prior art;

fig. 4 is a schematic flowchart of a first implementation of a policy control method for UPF reselection according to an embodiment of the present invention;

fig. 5 is a schematic flowchart of a second implementation of a policy control method for UPF reselection according to an embodiment of the present invention;

fig. 6 is a schematic flowchart of a third implementation of a policy control method for UPF reselection according to an embodiment of the present invention;

fig. 7 is a schematic flowchart of a fourth implementation of a policy control method for UPF reselection according to an embodiment of the present invention;

FIG. 8 is a schematic diagram of a first component of a PCF in an embodiment of the invention;

FIG. 9 is a diagram illustrating a second component of a PCF in an embodiment of the present invention;

FIG. 10 is a schematic diagram of a first component of an SMF in an embodiment of the invention;

fig. 11 is a schematic diagram of a second composition structure of the SMF in the embodiment of the present invention.

Detailed Description

The technical solution in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention.

In an embodiment of the present invention, fig. 4 is a schematic flowchart of a first implementation flow of a policy control method for UPF reselection in the embodiment of the present invention. As shown in fig. 4, the policy control method for UPF reselection may include the following steps:

step 401, obtaining an event notification of anchor point reselection occurring in the first PDU session, a validity period of a first IP address of the UE corresponding to the first UPF, and a second IP address of the UE corresponding to the second UPF from the SMF.

In the embodiment of the invention, the PCF acquires an event notice of anchor point reselection occurring in the first PDU session from the SMF, the validity period of the first IP address of the UE corresponding to the first UPF and the second IP address of the UE corresponding to the second UPF. Preferably, in an embodiment of the present invention, before the PCF acquires from the SMF an event notification of anchor reselection occurring in the first PDU session, a validity period of the first IP address of the UE corresponding to the first UPF, and a second IP address of the UE corresponding to the second UPF, the PCF may acquire the first IP address from the SMF during establishment of the first PDU session. Preferably, in the embodiment of the present invention, before the PCF obtains, from the SMF, an event notification of anchor point reselection occurring in the first PDU session, and a validity period of the first IP address of the UE corresponding to the first UPF and a second IP address of the UE corresponding to the second UPF, the PCF may further receive first service information corresponding to each target application provided by each AF; formulating a first strategy rule corresponding to each target application according to the first service information corresponding to each target application; and providing the strategy rules corresponding to the target applications to the SMF.

And step 402, sending the validity period of the first IP address and the second IP address to AF corresponding to each target application.

In the specific embodiment of the present invention, the PCF sends the validity period of the first IP address and the second IP address to the AF corresponding to each target application. Preferably, in the embodiment of the present invention, after the PCF sends the validity period of the first IP address and the second IP address to the AF corresponding to each target application, the PCF may further receive second service information corresponding to each target application provided by each AF; formulating a second strategy rule corresponding to each target application according to second service information corresponding to each target application; and providing the second policy rules corresponding to the target applications to the SMF. Preferably, in the embodiment of the present invention, after the PCF sends the validity period of the first IP address and the second IP address to the AF corresponding to each target application, the PCF may further receive an address of a target application server corresponding to each target application provided by each AF; and providing the address of the target application server corresponding to each target application to the SMF.

In the method for controlling a UPF reselection policy provided in the embodiment of the present invention, a PCF may first determine that an anchor reselection event occurs from a first PDU session, a validity period of a first IP address of a UE corresponding to a first UPF, and a second IP address of a UE corresponding to a second UPF; the PCF may then send the validity period of the first IP address and the second IP address to AFs corresponding to respective target applications. That is to say, in the technical solution of the embodiment of the present invention, the PCF may notify the AF corresponding to the first PDU session of the validity period of the IP address corresponding to the first UPF and the IP address of the second UPF, so that each target application may perform application layer reselection before the validity period of the first IP address, that is, perform service access by using the second IP address, and each target application may select an application server closer to the second UPF to continue providing services. In the prior art, the SMF can only perform UPF reselection for one of the target applications. Therefore, compared with the prior art, the policy control method for the UPF reselection provided by the embodiment of the invention can notify other target applications of events of the UPF reselection after one target application triggers the UPF reselection, so that the other target applications can perform application layer reselection within the validity period of the first IP address, and the use experience of other target applications accessed by the UE cannot be influenced; in addition, the technical scheme of the embodiment of the invention is simple and convenient to realize, convenient to popularize and wider in application range.

Fig. 5 is a flowchart illustrating a second implementation of a policy control method for UPF reselection according to an embodiment of the present invention. As shown in fig. 5, the policy control method for UPF reselection may include the following steps:

and step 501, when a preset trigger condition is met, performing anchor point reselection on the first PDU session.

In a specific embodiment of the present invention, when a preset trigger condition is met, the SMF performs anchor point reselection on the first PDU session. Preferably, in an embodiment of the present invention, before the SMF performs anchor point reselection on the first PDU session, the SMF may select a first UPF for the first PDU session and allocate a first IP address during establishment of the first PDU session; the PCF is notified of the first IP address. Preferably, in an embodiment of the present invention, the triggering condition includes at least one of the following: the SMF receives a flow guide request sent by any one target application; or the network load of the first UPF exceeds a preset threshold value; or the SMF receives the report of the user plane detection information sent by the first UPF. Preferably, in an embodiment of the present invention, after the SMF performs anchor reselection on the first UPF, the SMF may further change the first UPF session to a Multi-Homing PDU session; a second UPF is selected for the Multi-home PDU session and a second IP address is assigned. Preferably, in an embodiment of the present invention, after the SMF performs anchor point reselection on the first PDU session, the SMF may further notify the UE that the first PDU session is to be released after the validity period, so that the UE requests to establish a second PDU session; the first PDU session and the second PDU session are the same with the corresponding external data network DN; and the SMF receives a request message for establishing the second PDU session sent by the UE, selects a second UPF for the second PDU session and allocates a second IP address. Preferably, in an embodiment of the present invention, before the SMF performs anchor point reselection on the first PDU session, the SMF may further receive a first policy rule corresponding to each target application formulated by the PCF; formulating a first packet detection rule corresponding to each target application according to a first strategy rule corresponding to each target application; and providing the first packet detection rule corresponding to each target application to the second UPF. Preferably, in an embodiment of the present invention, before the SMF performs anchor point reselection on the first PDU session, the SMF may further receive an address of a source application server corresponding to each target application provided by the PCF; and providing the address of the source application server corresponding to each target application to the UE.

Step 502, notifying the PCF of the event notification of anchor point reselection, the validity period of the first IP address of the UE corresponding to the first UPF, and the second IP address of the UE corresponding to the second UPF.

In the specific embodiment of the present invention, the SMF notifies the PCF of the event notification of the occurrence of anchor reselection, the validity period of the first IP address of the UE corresponding to the first UPF, and the second IP address of the UE corresponding to the second UPF. Preferably, in the embodiment of the present invention, after the SMF notifies the PCF of the event notification of the anchor reselection occurrence, the validity period of the first IP address of the UE corresponding to the first UPF, and the second IP address of the UE corresponding to the second UPF, the SMF may further receive a second policy rule corresponding to each target application formulated by the PCF; formulating a second grouping detection rule corresponding to each target application according to a second strategy rule corresponding to each target application; the corresponding packet detection rule for each target application is provided to the second UPF. Preferably, in the embodiment of the present invention, after the SMF notifies the PCF of the event notification of the anchor reselection, the validity period of the first IP address of the UE corresponding to the first UPF, and the second IP address of the UE corresponding to the second UPF, the SMF may further receive the address of the target application server corresponding to each target application provided by the PCF; and providing the addresses of the target application servers corresponding to the target applications to the UE.

According to the UPF reselection strategy control method provided by the embodiment of the invention, when the preset trigger condition is met, the SMF can execute anchor point reselection on the first PDU session; the SMF may then notify the PCF of the event notification of the occurrence of anchor reselection, as well as the validity period of the first IP address of the UE corresponding to the first UPF and the second IP address of the UE corresponding to the second UPF. That is to say, in the technical solution of the embodiment of the present invention, the SMF may notify the PCF of an event that anchor reselection occurs, a validity period of a first IP address of the UE corresponding to the first UPF, and a second IP address of the UE corresponding to the second UPF, and then the PCF may notify the validity period of the IP address corresponding to the first UPF and the IP address of the second UPF to AFs corresponding to target applications, so that each target application may perform application layer reselection before the validity period of the first IP address, that is, perform service access by using the second IP address, and each target application may select an application server closer to the second UPF to continue providing services. In the prior art, the SMF can only perform UPF reselection for one of the target applications. Therefore, compared with the prior art, the policy control method for the UPF reselection provided by the embodiment of the invention can notify other target applications that the UE is visiting of the event of the UPF reselection after one target application triggers the UPF reselection, so that the other target applications can perform the application layer reselection within the validity period of the first IP address without affecting the use experience of the other target applications that the UE is visiting; in addition, the technical scheme of the embodiment of the invention is simple and convenient to realize, convenient to popularize and wider in application range.

Fig. 6 is a schematic flow chart of a third implementation of the policy control method for UPF reselection according to the embodiment of the present invention. As shown in fig. 6, the policy control method for UPF reselection may include the following steps:

step 601, the UE initiates an attach procedure to the AMF through the base station to complete network registration of the UE in the AMF.

Step 602, the UE initiates a PDU session setup request message of the first PDU session to the AMF; the PDU session establishment request message may carry a first PDU session identifier, a request type, N1 session management Information (SM Information), and a Data Network identifier (DN Name).

Step 603, the AMF sends a session management request message to the selected SMF; wherein, the session management request message can carry a user identifier; DN Name, first DPU session identity, user location Information, SSC Mode, and N1 session management Information (N1 SM Information).

Step 604, the SMF selects a UPF for the first PDU session as an anchor UPF (denoted as the first UPF), and assigns an IP address (here, IPv6 prefix1, denoted as the first IP address) corresponding to the anchor UPF to the UE. SMF sends a first strategy request message corresponding to the first PDU session to PCF; the first policy request message may carry a user identifier, a DN Name, an SSC Mode, and an IPv6 prefix 1.

In this step, before the SMF sends the policy request message corresponding to the first PDU session to the PCF, the SMF may also interact with the unified data management UDM, obtain subscription information of the user, and check the UE. In addition, the SMF can also report the capability indication that the UE supports Multi-Homed to the PCF.

Step 605, PCF returns the first policy acknowledge message to SMF; wherein, the first policy confirmation message may carry a default policy.

In a specific embodiment of the present invention, the default policy may include: aggregate Maximum rate (AMBR), QoS parameters, and event trigger.

Step 606, the SMF sends a session establishment request message of N4 to the first UPF; the first UPF returns an N4 session establishment confirmation message to the SMF; wherein, the N4 session establishment request message may carry a packet detection rule.

In a specific embodiment of the present invention, after receiving the N4 session establishment request message sent by the SMF, the first UPF may install/activate the packet detection rule carried in the N4 session establishment request message, and return an N4 session establishment confirmation message to the SMF. If the first UPF allocates CN tunnel information, the N4 session establishment confirmation message returned by the first UPF to the SMF may also carry the CN tunnel information.

Step 607, the SMF sends a session management response message to the AMF; wherein, the session management response message may carry N2 session management Information (N2 SM Information) and N1 session management Information (N1 SM Information).

Step 608, the AMF sends a session request message of N2 PDU to the base station; wherein, the N2 PDU session request message may carry N2 session management information and NAS information.

Step 609, the base station sends a specific signaling of an Access Network (AN) (Access network) to the UE; and provides the UE with the information received from the SMF.

Step 610, the base station sends a session response message of N2 PDU to AMF; wherein, the N2 PDU session answer message may carry a first PDU session identifier and N2 session management information.

Step 611, the AMF sends a N2 session management request message to the SMF; wherein, the N2 session management request message may carry N2 session management information.

Step 612, the AMF sends a session establishment request message of N4 to the first UPF; the first UPF returns an N4 session setup confirm message to the AMF.

Step 613, SMF returns N2 session management answer message to AMF.

Step 614, the SMF sends an IPv6 Route Advertisement (RA) message to the UE through the first UPF; the IPv6 route advertisement message may carry a first IP address.

In the specific embodiment of the present invention, the UE performs service access through the established first PDU session, and can simultaneously access multiple target applications. The AF corresponding to each target application can directly interact with the PCF; and the network element can also interact with the PCF through the NEF, and provide the PCF with relevant service information for policy decision of the PCF. The first service information corresponding to each target application provided by the AF to the PCF may carry information such as a first IP address, a first media description component, and a bandwidth requested for the first time; the second service information corresponding to each target application provided by the AF to the PCF may carry information such as a second IP address, a second media description component, and a bandwidth requested for the second time.

And step 615, when the SMF meets the preset triggering condition, the SMF executes a Multi-Homed decision on the first PDU session.

In a specific embodiment of the present invention, the trigger condition may include: the SMF receives a flow guide request sent by any one target application; or the network load of the first UPF exceeds a preset threshold value; or the SMF receives the report of the user plane detection information sent by the first UPF. That is, any third-party application may find that the location of the UE and the location of the first UPF are not the best path to access the third-party application, the third-party application may send a traffic steering request to the SMF, and the SMF may decide to reselect the UPF after receiving the traffic steering request sent by the third-party application; or, when the network load of the first UPF exceeds a preset threshold, the SMF may decide to reselect the UPF; or, the SMF receives the report of the user plane detection information, and the SMF may decide to reselect the UPF.

Step 616, the SMF selects a new UPF as the new anchor UPF (denoted as the second UPF), and assigns a new IP address (here, IPv6 perfix2, denoted as the second UPF) corresponding to the new anchor UPF to the UE. SMF sends a second strategy request message corresponding to the first PDU session to PCF; wherein, the second policy request message may carry at least validity periods of IPv6 prefix1, IPv6 prefix2, and IPv6 prefix 1.

Step 617, the PCF performs policy authorization. The PCF decides to install or activate the policy rules for the second UPF. The PCF returns a second policy acknowledgment message to the SMF.

Step 618, SMF will select a UPF (denoted as the third UPF) as the Branching Point (BP); the SMF sends an N4 session establishment request message to the second UPF; the second UPF returns an N4 session establishment confirmation message to the SMF; wherein, the N4 session establishment request message may carry a packet detection rule.

In an embodiment of the present invention, after receiving the N4 session establishment request message sent by the SMF, the second UPF may install/activate the packet detection rule carried in the N4 session establishment request message, and return an N4 session establishment confirmation message to the SMF. If the second UPF allocates the CN tunnel information, the N4 session establishment confirmation message returned by the second UPF to the SMF may also carry the CN tunnel information.

Step 619, the SMF sends a session establishment message of N4 to the BP; the BP returns an N4 session confirmation message to the SMF; the N4 session setup message may carry the tunnel information of the first UPF, the tunnel information of the second UPF, and the tunnel information of the RAN.

In the specific embodiment of the present invention, the SMF may also send a packet detection rule to the BP, which is used to forward the upstream data whose source address matches IPv6 prefix1 to the first UPF, and forward the upstream data whose source address matches IPv6 prefix2 to the second UPF; while downlink data from either the first UPF or the second UPF is sent to the RAN. If the CN tunnel information is allocated by the first UPF, the N4 session confirmation message returned by the BP to the SMF may carry the tunnel information of the BP.

Step 620, if the CN tunnel information is allocated by the second UPF, the SMF sends a N4 session modification request message to the second UPF; the second UPF returns an N4 session modification acknowledgment message to the SMF; wherein, the N4 session modification request message carries tunnel information of BP.

Step 621, the SMF sends a N4 session modification request message to the first UPF; the first UPF returns an N4 session modification acknowledgment message to the SMF; wherein, the N4 session modification request message carries tunnel information of BP.

Step 622, the SMF sends a session modification request message to the base station through the AMF; the base station returns a session modification response message to the SMF through the AMF; wherein, the session modification request message may carry tunnel information of BP.

Step 623, the SMF sends an IPv6 route advertisement message (IPv6 RA message) to the UE through the first UPF; the IPv6 RA message may carry a first IP address and a validity period.

Step 624, the SMF sends an IPv6 RA message to the UE through the second UPF; wherein, the IPv6 RA message may carry a second IP address.

Step 625, the PCF makes a policy decision.

In this step, PCF determines each target application that UE is accessing and needs to perform service flow migration; in addition, the PCF needs to consider whether each target application supports application layer reselection. The target applications are applications which provide service information and request QoS guarantee for the service through interaction between AF and PCF after the first PDU session is established.

Step 626, PCF sends a UPF reselection request message to the AF corresponding to the target application; wherein, the UPF reselection message may carry at least a validity period of the first IP address and the second IP address. Optionally, the UPF reselection message may further carry location information of the second UPF.

Step 627, in the validity period of the first IP address, each target application interacts with the UE to reselect the application layer, the UE accesses by using the IP address (i.e. the second IP address) generated by the new IPv6 Prefix2, each target application may select a target application server of the second UPF that is closer to the target application server to continue providing access, and then the UE needs to interact with each target application server.

Step 628, the AF corresponding to each target application returns a UPF reselection confirmation message to the PCF; the UPF reselection confirmation message may carry the second service information after application layer reselection. Optionally, the UPF reselection confirmation message may also carry addresses of the target application servers.

Step 629, the PCF updates the policy decision according to the acknowledgement message returned by the AF, and the PCF executes the policy according to the second service information of each target application provided by the AF. The PCF interacts with the SMF to provide a policy rule of the target application to be migrated, and if the AF provides the address of the target application server of the target application, the address of the target application server can be carried in the confirmation message.

Step 630, the SMF sends a N4 session establishment request message to the second UPF, for providing policy rules corresponding to each target application to the second UPF; the second UPF returns an N4 session setup confirm message to the SMF.

Step 631, the SMF sends an IPv6 RA message to the UE through the second UPF; wherein, the IPv6 RA message may carry a second IP address (i.e. IPv6 prefix 2) and routing option information; the routing option information may carry an address of the target application server.

In a specific embodiment of the present invention, steps 626-631 are performed for each PCF determining the applications that need to be notified.

In the policy control method for UPF reselection provided in the embodiment of the present invention, a PCF may first notify an event of anchor point reselection from a first PDU session, and a validity period of a first IP address of a UE corresponding to a first UPF and a second IP address of a UE corresponding to a second UPF; the PCF may then send the validity period of the first IP address and the second IP address to AFs corresponding to respective target applications. That is to say, in the technical solution of the embodiment of the present invention, the PCF may notify the AF corresponding to the first PDU session of the validity period of the IP address corresponding to the first UPF and the IP address of the second UPF, so that each target application may perform application layer reselection before the validity period of the first IP address, that is, perform service access by using the second IP address, and each target application may select an application server closer to the second UPF to continue providing services. In the prior art, the SMF can only perform UPF reselection for one of the target applications. Therefore, compared with the prior art, the policy control method for the UPF reselection provided by the embodiment of the invention can notify other target applications that the UE is visiting of the event of the UPF reselection after one target application triggers the UPF reselection, so that the other target applications can perform the application layer reselection within the validity period of the first IP address without affecting the use experience of the other target applications that the UE is visiting; in addition, the technical scheme of the embodiment of the invention is simple and convenient to realize, convenient to popularize and wider in application range.

Fig. 7 is a schematic flowchart of a fourth implementation of the policy control method for UPF reselection according to the embodiment of the present invention. As shown in fig. 7, the policy control method for UPF reselection may include the following steps:

step 701, the UE initiates an attach procedure to the AMF through the base station to complete network registration of the UE in the AMF.

Step 702, UE initiates a PDU session establishment request message of a first PDU session to AMF; the PDU session establishment request message may carry a first PDU session identifier, a request type, N1 session management Information (SM Information), and a Data Network identifier (DN Name).

Step 703, the AMF sends a session management request message to the selected SMF; wherein, the session management request message can carry a user identifier; DN Name, first PDU session identification, user location Information, SSC Mode, and N1 session management Information (N1 SM Information).

Step 704, the SMF selects a UPF for the first PDU session as an anchor UPF (denoted as the first UPF), and allocates an IP address (here, IPv6 prefix1 or IPv4address 1, denoted as the first IP address) corresponding to the anchor UPF to the UE. SMF sends a first strategy request message corresponding to the first PDU session to PCF; the first policy request message may carry a user identifier, a DN Name, an SSC Mode, and a first IP address.

In this step, before the SMF sends the policy request message corresponding to the PDU session to the PCF, the SMF may also interact with the unified data management UDM, obtain subscription information of the user, and check the UE.

Step 705, PCF returns a first policy acknowledgement message to SMF; wherein, the first policy confirmation message may carry a default policy.

Step 706, the SMF sends a N4 session establishment request message to the first UPF; the first UPF returns an N4 session establishment confirmation message to the SMF; wherein, the N4 session establishment request message may carry a packet detection rule.

Step 707, the SMF sends a session management response message to the AMF; wherein, the session management response message may carry N2 session management Information (N2 SM Information) and N1 session management Information (N1 SM Information).

Step 708, the AMF sends a N2 PDU session request message to the base station; wherein, the N2 PDU session request message may carry N2 session management information and NAS information.

Step 709, the base station sends AN AN specific signaling to the UE; and provides the UE with the information received from the SMF.

Step 710, the base station sends a session response message of N2 PDU to AMF; wherein, the N2 PDU session answer message may carry a first PDU session identifier and N2 session management Information (N2 SM Information).

Step 711, the AMF sends a session management request message of N2 to the SMF; wherein, the N2 session management request message may carry N2 session management Information (N2 SM Information).

Step 712, the AMF sends a session establishment request message of N4 to the first UPF; the first UPF returns an N4 session setup confirm message to the AMF.

Step 713, SMF returns N2 session management answer message to AMF.

Step 714, optionally, if the first IP address is not allocated in step 707, the SMF sends an address configuration message to the UE through the first UPF to allocate the first IP address. Such as an IPv6 Route Advertisement (RA) message.

And 715, when the SMF meets the preset triggering condition, performing anchor point UPF reselection through multi-PDU session establishment.

Step 716, the SMF sends NAS notification message to the UE; the NAS notification message may carry the first PDU session identifier and a validity period of the first IP address (i.e., a time for which the first PDU session is to be maintained).

In this step, the SMF informs the UE that the first PDU session is to be released after a period of time, and at the same time informs the UE to request to establish a second PDU session to the same DN.

Step 717, the UE initiates a PDU session setup request message of the second PDU session to the AMF; the PDU session establishment request message may carry a first PDU session identifier, a second PDU session identifier, a request type, N1 session management Information (SM Information), and a Data Network identifier (DN Name).

Step 718, the AMF selects the same SMF according to the first PDU session identifier; the AMF sends a session management request message to the selected SMF; wherein, the session management request message can carry a user identifier; DN Name, first PDU session identification, second PDU session identification, user location Information, SSC Mode, and N1 session management Information (N1 SM Information).

Step 719, the SMF selects the second UPF for the second PDU session as a new anchor UPF, and allocates a second IP address (which may be IPv4address 2 or IPv6 prefix 2) corresponding to the second UPF to the UE. SMF sends a second strategy request message corresponding to the second PDU session to PCF; the second policy request message may carry a user identifier, a DN Name, an SSC Mode, and a second IP address.

In this step, before the SMF sends the second policy request message corresponding to the second PDU session to the PCF, the SMF may also interact with the unified data management UDM to obtain subscription information of the user, and check the UE.

Step 720, PCF returns the second strategy affirmation message to SMF; wherein, the second policy confirmation message may carry a default policy.

Step 721, the SMF sends a N4 session establishment request message to the second UPF; the second UPF returns an N4 session establishment confirmation message to the SMF; wherein, the N4 session establishment request message may carry a packet detection rule.

Step 722, the SMF sends a session management response message to the AMF; wherein, the session management response message may carry N2 session management Information (N2 SM Information) and N1 session management Information (N1 SM Information).

Step 723, the AMF sends a N2 PDU session request message to the base station; wherein, the N2 PDU session request message may carry N2 session management information and NAS information.

Step 724, the base station sends AN AN specific signaling to the UE; and provides the UE with the information received from the SMF.

Step 725, the base station sends a N2 PDU session response message to the AMF; wherein, the N2 PDU session response message may carry a PDU session identifier and N2 session management Information (N2 SM Information).

Step 726, the AMF sends a N2 session management request message to the SMF; wherein, the N2 session management request message may carry N2 session management Information (N2 SM Information).

Step 727, the AMF sends a session modification request message of N4 to the first UPF; the first UPF returns an N4 session modification confirm message to the AMF.

Step 728, SMF returns N2 session management answer message to AMF.

Step 729, optionally, if the second IP address is not allocated in step 622, the SMF sends an address configuration message to the UE via the second UPF to allocate the second IP address. Such as an IPv6 Route Advertisement (RA) message.

Step 730, the PCF makes a policy decision.

In this step, PCF determines each target application that UE is accessing and needs to perform service flow migration; in addition, the PCF needs to consider whether each target application supports application layer reselection. The applications are applications which provide service information and request QoS guarantee for the service through interaction between AF and PCF after the first PDU session is established.

Step 731, PCF sends a UPF reselection request message to the AF corresponding to the target application; wherein, the UPF reselection message may carry at least a validity period of the first IP address and the second IP address. Optionally, the location information of the second UPF may also be carried in the UPF reselection message.

Step 732, during the validity period of the first IP address, each target application interacts with the UE to reselect the application layer, the UE accesses with the new second IP address, and each target application may select a target application server closer to the second UPF to continue providing access, so that the UE needs to interact with each target application server.

Step 733, the AF corresponding to each target application returns a UPF reselection confirmation message to the PCF; the UPF reselection confirmation message may carry the second service information after the application layer reselection. Optionally, the UPF reselection confirmation message may further carry an address of the target application server.

Step 734, the PCF updates the policy decision according to the confirmation information returned by the AF, and the PCF makes a policy according to the second service information of each target application provided by the AF. The PCF interacts with the SMF and provides a policy rule of the target application needing to be migrated, and if the AF provides the address of the target application server of the target application, the address of the target application server can be carried in the confirmation information.

Step 735, the SMF sends a N4 session modification request message to the second UPF; the second UPF returns an N4 session modification acknowledgment message to the SMF.

Step 736, optionally, the SMF sends an address configuration message, such as an IPv6 RA message, to the UE through the second UPF; wherein, the IPv6 RA message may carry IPv6 prefix2 and routing option information; wherein, the routing information option information carries the address of the target application server.

In a specific embodiment of the present invention, steps 731-736 are performed for each PCF determining the applications that need to be notified.

Fig. 8 is a schematic diagram of a first component structure of a PCF in an embodiment of the present invention. As shown in fig. 8, the PCF includes: an acquisition unit 801 and a transmission unit 802; wherein,

the acquiring unit 801 is configured to acquire, from the SMF, an event notification of anchor point reselection occurring in the first PDU session, a validity period of a first IP address of the UE corresponding to the first UPF, and a second IP address of the UE corresponding to the second UPF;

the sending unit 802 is configured to send the first IP address, the validity period, and the second IP address to an AF corresponding to each target application.

Further, the obtaining unit 801 is further configured to obtain the first IP address from the SMF in the process of establishing the first PDU session.

Fig. 9 is a schematic diagram of a second component structure of a PCF in an embodiment of the present invention. As shown in fig. 9, the PCF further comprises: a policy rule making unit 803, configured to receive first service information corresponding to each target application provided by each AF; formulating a first strategy rule corresponding to each target application according to the first service information corresponding to each target application;

the sending unit 802 is further configured to provide the policy rule corresponding to each target application to the SMF.

Further, the policy rule making unit 803 is further configured to receive second service information corresponding to each target application provided by each AF; formulating a second strategy rule corresponding to each target application according to second service information corresponding to each target application;

the sending unit 802 is further configured to provide the second policy rule corresponding to each target application to the SMF.

Further, the obtaining unit 801 is further configured to receive addresses of target application servers corresponding to the target applications provided by the respective AFs;

the sending unit 802 is further configured to provide the SMF with addresses of target application servers corresponding to the target applications.

In the PCF provided in the embodiment of the present invention, the PCF may first generate an event notification of anchor point reselection from the first PDU session, and a validity period of a first IP address of the UE corresponding to the first UPF and a second IP address of the UE corresponding to the second UPF; the PCF may then send the validity period of the first IP address and the second IP address to AFs corresponding to respective target applications. That is to say, in the technical solution of the embodiment of the present invention, the PCF may notify the AF corresponding to the first PDU session of the validity period of the IP address corresponding to the first UPF and the IP address of the second UPF, so that each target application may perform application layer reselection before the validity period of the first IP address, that is, perform service access by using the second IP address, and each target application may select an application server closer to the second UPF to continue providing services. In the prior art, the SMF can only perform UPF reselection for one of the target applications. Therefore, compared with the prior art, the PCF provided in the embodiment of the present invention can notify the UE of the event of the UPF reselection of the other target application being accessed because one target application triggers the UPF reselection, so that the other target application performs the application layer reselection within the validity period of the first IP address, and the usage experience of the other target application being accessed by the UE is not affected; in addition, the technical scheme of the embodiment of the invention is simple and convenient to realize, convenient to popularize and wider in application range.

Fig. 10 is a schematic diagram of a first composition structure of an SMF in an embodiment of the present invention. As shown in fig. 10, the SMF includes: an anchor reselection unit 1001 and a notification unit 1002; wherein,

the anchor reselection unit 1001 is configured to perform anchor reselection on the first PDU session when a preset trigger condition is met;

the notifying unit 1002 is configured to notify the PCF of an event notification of anchor reselection, a validity period of a first IP address of the UE corresponding to the first UPF, and a second IP address of the UE corresponding to the second UPF.

Fig. 11 is a schematic diagram of a second composition structure of the SMF in the embodiment of the present invention. As shown in fig. 11, the SMF further includes: an address allocating unit 1003, configured to select the first UPF for the first PDU session in the process of establishing the first PDU session, and allocate the first IP address;

the notifying unit 1002 is further configured to notify the PCF of the first IP address.

Further, the trigger condition includes at least one of:

receiving a flow guide request sent by any one target application;

or the network load of the first UPF exceeds a preset threshold value;

Further, the address allocating unit 1003 is further configured to change the first UPF session to a Multi-Homing PDU session; selecting the second UPF for the Multi-Homing PDU session and assigning the second IP address.

Further, the notifying unit 1002 is further configured to notify the UE that the first PDU session is to be released after the validity period, so that the UE requests to establish a second PDU session; wherein the first PDU session is the same as the external data network DN corresponding to the second PDU session;

the address allocating unit 1003 is further configured to receive a request message for establishing the second PDU session, which is sent by the UE, select the second UPF for the second PDU session, and allocate the second IP address.

Further, the SMF further includes: a detection rule making unit 1004, configured to receive a first policy rule corresponding to each target application made by the PCF; formulating a first packet detection rule corresponding to each target application according to a first strategy rule corresponding to each target application;

the notifying unit 1002 is further configured to provide the first packet detection rule corresponding to each target application to the second UPF.

Further, the detection rule making unit 1004 is further configured to receive a second policy rule corresponding to each target application made by the PCF; formulating a second grouping detection rule corresponding to each target application according to a second strategy rule corresponding to each target application;

the notifying unit 1002 is further configured to provide the second UPF with the corresponding packet detection rule of each target application.

Further, the anchor reselection unit 1001 is further configured to receive an address of a source application server corresponding to each target application provided by the PCF;

the notifying unit 1002 is further configured to provide the address of the source application server corresponding to each target application to the UE.

Further, the anchor reselection unit 1001 is further configured to receive addresses of target application servers corresponding to the target applications, where the addresses are provided by the PCF;

the notifying unit 1002 is further configured to provide the address of the target application server corresponding to each target application to the UE.

According to the SMF provided by the embodiment of the invention, when the preset trigger condition is met, the SMF can execute anchor point reselection on the first PDU session; the SMF may then notify the PCF of the event notification of the occurrence of anchor reselection, as well as the validity period of the first IP address of the UE corresponding to the first UPF and the second IP address of the UE corresponding to the second UPF. That is to say, in the technical solution of the embodiment of the present invention, the SMF may notify the PCF of an event that anchor reselection occurs, a validity period of a first IP address of the UE corresponding to the first UPF, and a second IP address of the UE corresponding to the second UPF, and then the PCF may notify the validity period of the IP address corresponding to the first UPF and the IP address of the second UPF to AFs corresponding to target applications, so that each target application may perform application layer reselection before the validity period of the first IP address, that is, perform service access by using the second IP address, and each target application may select an application server closer to the second UPF to continue providing services. In the prior art, the SMF can only perform UPF reselection for one of the target applications. Therefore, compared with the prior art, the SMF provided in the embodiment of the present invention can notify the UE of the event of the UPF reselection of the other target application being accessed because one target application triggers the UPF reselection, so that the other target application performs the application layer reselection within the validity period of the first IP address, and the usage experience of the other target application being accessed by the UE is not affected; in addition, the technical scheme of the embodiment of the invention is simple and convenient to realize, convenient to popularize and wider in application range.

In practical applications, the obtaining unit 801, the sending unit 802, and the policy rule making unit 803 may be implemented by a Central Processing Unit (CPU), a microprocessor unit (MPU), a Digital Signal Processor (DSP), or a Field Programmable Gate Array (FPGA), etc. located in the PCF; the anchor point reselection unit 1001, the notification unit 1002, and the address assignment unit 1003 may be implemented by a Central Processing Unit (CPU), a microprocessor unit (MPU), a Digital Signal Processor (DSP), a Field Programmable Gate Array (FPGA), or the like, which is located in the SMF.

In addition, each unit in the embodiment may exist alone physically, or two or more units may be integrated into one unit. The integrated unit can be realized in a form of hardware or a form of a software functional module.

Based on the understanding that the technical solution of the present embodiment essentially or a part contributing to the prior art, or all or part of the technical solution may be embodied in the form of a software product stored in a storage medium, and include several instructions for enabling a host (which may be a personal mobile terminal, a server, or a network device, etc.) or a processor (processor) to execute all or part of the steps of the method of the present embodiment. And the aforementioned storage medium includes: a U-disk, a removable hard disk, a Read Only Memory (ROM), a Random Access Memory (RAM), a magnetic disk or an optical disk, and other various media capable of storing program codes.

Specifically, the program instructions corresponding to the policy control method for UPF reselection in this embodiment may be stored in a storage medium such as an optical disc, a hard disc, a usb disk, or the like, and when the program instructions corresponding to the policy control method for UPF reselection in the storage medium are read or executed by an electronic device, the method includes the following steps:

acquiring an event notification of anchor point reselection of a first PDU session from the SMF, and a validity period of a first IP address of User Equipment (UE) corresponding to a first UPF and a second IP address of the UE corresponding to a second UPF;

As will be appreciated by one skilled in the art, embodiments of the present invention may be provided as a method, system, or computer program product. Accordingly, the present invention may take the form of a hardware embodiment, a software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, optical storage, and the like) having computer-usable program code embodied therein.

The present invention is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each flow and/or block of the flow diagrams and/or block diagrams, and combinations of flows and/or blocks in the flow diagrams and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.

These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks.

These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.

The above description is only a preferred embodiment of the present invention, and is not intended to limit the scope of the present invention.

Claims

1. A policy control method for UPF reselection, applied to PCF, is characterized in that the method comprises:

providing the strategy rules corresponding to the target applications to the SMF;

acquiring a first IP address from the SMF in the establishment process of a first PDU session; acquiring an event notice of anchor point reselection of a first Protocol Data Unit (PDU) session from a Session Management Function (SMF), a validity period of a first IP address of User Equipment (UE) corresponding to a first UPF and a second IP address of the UE corresponding to a second UPF;

sending the validity period of the first IP address and the second IP address to an application function entity (AF) corresponding to each target application;

providing the address of a target application server corresponding to each target application to the SMF;

2. A policy control method for UPF reselection, applied to SMF, the method comprising:

providing the first packet detection rule corresponding to each target application to a second UPF;

in the process of establishing a first PDU session, selecting a first UPF for the first PDU session, and allocating a first IP address;

notifying the PCF of the first IP address;

notifying the event notification of anchor point reselection, the validity period of the first IP address of the UE corresponding to the first UPF and the second IP address of the UE corresponding to the second UPF to a policy control function entity PCF;

providing the addresses of the target application servers corresponding to the target applications to the UE;

3. The method of claim 2, wherein the triggering condition comprises at least one of:

receiving a flow guide request sent by any one target application;

or the network load of the first UPF exceeds a preset threshold value;

4. The method of claim 2, wherein after performing an anchor reselection to the first UPF, the method further comprises:

changing the first UPF session into a Multi-Homing PDU session;

5. The method of claim 2, wherein after the performing an anchor reselection for the first PDU session, the method further comprises:

6. The method of claim 2, wherein prior to the performing anchor reselection for the first PDU session, the method further comprises:

7. A PCF, wherein said PCF comprises: the system comprises an acquisition unit, a sending unit and a strategy rule making unit; wherein,

sending the first IP address, the validity period and the second IP address to AF corresponding to each target application;

an obtaining unit, further configured to obtain the first IP address from the SMF in a process of establishing the first PDU session; the policy rule making unit is used for receiving first service information corresponding to each target application provided by each AF; formulating a first strategy rule corresponding to each target application according to the first service information corresponding to each target application;

the sending unit is further configured to provide the policy rules corresponding to the respective target applications to the SMF;

the policy rule making unit is further configured to receive second service information corresponding to each target application provided by each AF; formulating a second strategy rule corresponding to each target application according to second service information corresponding to each target application;

the sending unit is further configured to provide a second policy rule corresponding to each target application to the SMF;

the acquiring unit is further configured to receive addresses of target application servers corresponding to the target applications provided by the AFs;

8. An SMF, wherein the SMF comprises: an anchor point reselection unit and a notification unit; wherein,

the notification unit is used for notifying the PCF of an event of anchor point reselection, the validity period of the first IP address of the UE corresponding to the first UPF and the second IP address of the UE corresponding to the second UPF;

an address allocation unit, configured to select the first UPF for the first PDU session in the process of establishing the first PDU session, and allocate the first IP address;

the notifying unit is further configured to notify the PCF of the first IP address;

the anchor point reselection unit is further configured to receive an address of a target application server corresponding to each target application provided by the PCF;

the notification unit is further configured to provide the addresses of the target application servers corresponding to the target applications to the UE;

a detection rule making unit, configured to receive a first policy rule corresponding to each target application made by the PCF; formulating a first packet detection rule corresponding to each target application according to a first strategy rule corresponding to each target application;

the notification unit is further configured to provide the first packet detection rule corresponding to each target application to the second UPF;

the detection rule making unit is further configured to receive a second policy rule corresponding to each target application made by the PCF; formulating a second grouping detection rule corresponding to each target application according to a second strategy rule corresponding to each target application;

9. The SMF of claim 8, wherein said trigger condition comprises at least one of:

receiving a flow guide request sent by any one target application;

or the network load of the first UPF exceeds a preset threshold value;

10. The SMF according to claim 8, wherein the address assignment unit is further configured to change the first UPF session to a Multi-homed PDU session; selecting the second UPF for the Multi-Homing PDU session and assigning the second IP address.

11. The SMF according to claim 8, wherein said notifying unit is further configured to notify said UE that said first PDU session is to be released after said validity period, so that said UE requests to establish a second PDU session; wherein the first PDU session is the same as the external data network DN corresponding to the second PDU session;

12. The SMF according to claim 8, wherein the anchor reselection unit is further configured to receive an address of a source application server corresponding to each target application provided by the PCF;