CN108738082B

CN108738082B - Session processing method, device and system

Info

Publication number: CN108738082B
Application number: CN201710239457.1A
Authority: CN
Inventors: 丁辉; 王晓燕
Original assignee: Huawei Technologies Co Ltd
Current assignee: Huawei Technologies Co Ltd
Priority date: 2017-04-13
Filing date: 2017-04-13
Publication date: 2020-06-16
Anticipated expiration: 2037-04-13
Also published as: CN108738082A

Abstract

The embodiment of the application discloses a session processing method, a session processing device and a session processing system, which are used for reducing signaling overhead. The method in the embodiment of the application comprises the following steps: a session management function entity (SMF) sends a PDU session reestablishment instruction to User Equipment (UE); the SMF receives a setup request of a second Packet Data Unit (PDU) session from the UE, wherein the setup request comprises first indication information; and the SMF determines a first policy control session according to the first indication information and the association information of the first policy control session, and determines the policy control session corresponding to the second PDU session as the first policy control session.

Description

Session processing method, device and system

Technical Field

The present application relates to the field of communications, and in particular, to a session processing method, device and system.

Background

A Packet Data Unit (PDU) session is a session service in which a User Equipment (UE) and a Data Network (DN) realize connectivity. In a 5G (first-generation) mobile communication system, before a UE initiates a service request to an Application Function entity (AF), a PDU session is established, and during the process of establishing the PDU session, a policy control session and establishment of a session of the AF are also triggered. The Policy Control Session is a Session established between a Session Management Function (SMF) and a Policy Control Function (PCF), and is used for issuing a Policy at a Session or service flow level. An AF session is a session established between an AF and a PCF for application layer to network layer policy requests.

In order to meet different service and Session continuity requirements of applications, the 5G (fine-generation) network introduces the following three Session continuity modes (SSC modes):

(1) SSC mode 1: in a session period of a PDU session, a user plane termination Function (TUPF) remains unchanged, an Internet Protocol (IP) address of the UE does not change, and a network side guarantees the continuity of the session. Among them, TUPF can be regarded as a user plane functional entity with anchor function.

(2) SSC mode 2: the TUPF has a coverage range, and the UE leaves the corresponding service range to trigger the TUPF change; when the TUPF is changed, the PDU conversation of the user on the original TUPF is released, and the PDU conversation is rebuilt on the changed TUPF; at this time, the IP address of the UE is changed, and the network side does not maintain the continuity of the session.

(3) SSC mode 3: the TUPF has a coverage range, and the UE leaves the corresponding service range to trigger the TUPF change; at this time, although TUPF is changed, it is necessary to ensure continuity of traffic. There are two guarantee modes: the first method needs application layer cooperation, when the TUPF is changed, the application layer binds the existing data flow from the TUPF before the change to the TUPF after the change; the second method does not require application layer cooperation, the existing data flow is still bound to the TUPF before the change, and the newly generated data flow is bound to the TUPF after the update.

For the SSC mode 2 type PDU session, in the prior art, when a TUPF change occurs, the network side releases the current PDU session and the policy related session, and notifies the UE to reinitiate the PDU session establishment request. In re-establishing the PDU session, the policy control session and the session related thereto (e.g., AF session) will also be re-created.

Since only the TUPF is changed and the policy is not changed, the process of reestablishing the policy control session triggers the AF session reestablishment, which brings unnecessary operation to the AF and wastes the signaling overhead of the AF.

Disclosure of Invention

The embodiment of the application provides a session processing method, a session processing device and a session processing system, which are used for reducing signaling overhead brought by reestablishment of a policy control session and an AF session.

A first aspect of an embodiment of the present application provides a session processing method, where the method includes:

when a PDU session needs to be released and reestablished, the SMF sends a PDU session reestablishment instruction to the UE corresponding to the PDU session; after receiving the PDU session reestablishment instruction, the UE releases the PDU session, namely releases the first PDU session, and then sends a second PDU session establishment request to the SMF, wherein the establishment request comprises first indication information; after receiving a request for establishing a second PDU session from the UE, the SMF determines a first policy control session according to first indication information in the request for establishing and association information of the first policy control session, and determines the first policy control session as a policy control session corresponding to the second PDU session corresponding to the request for establishing.

It should be understood that the association information of the first policy control session refers to information that has an association relationship with the first policy control session and can be used to determine the first policy control session, and the information is pre-stored by the SMF before receiving the establishment request.

It should also be understood that the first and second PDU sessions refer to a PDU session between the same UE and DN, the first PDU session is established first and released after the UE receives the reestablishment indication, and the second PDU session is established after the first PDU session is released.

The SMF in the embodiment of the application can associate the original strategy control session with the newly-established PDU session, so that the strategy control session cannot be reestablished in the process of reestablishing the PDU session, the release of the AF session is avoided, and the signaling overhead brought by reestablishing the strategy control session and reestablishing the AF session is reduced.

Based on the first aspect of the embodiment of the present application, in a first implementation manner of the first aspect of the embodiment of the present application, the association information of the policy control session may include: a first correspondence between the first PDU session and the first policy control session. Based on the first implementation manner of the first aspect of the embodiment of the present application, in the second implementation manner of the first aspect of the embodiment of the present application, the first corresponding relationship may include: the UE identification of the UE and the first PDU session identification of the first PDU session are in corresponding relation with the strategy control session identification of the first strategy control session; correspondingly, the first indication information may include: the UE identifier and the first PDU session identifier;

after receiving the establishment request, the SMF may determine, according to the correspondence, a policy control session identifier corresponding to the UE identifier and the first PDU session identifier carried in the establishment request, and then determine that the policy control session identified by the policy control session identifier is the first policy control session.

The embodiment of the application provides a specific mode for determining the first policy control session through the association information and the first indication information, and the realizability of the scheme is improved.

Based on the first implementation manner of the first aspect of the embodiment of the present application, in a third implementation manner of the first aspect of the embodiment of the present application, the first corresponding relationship may include: the corresponding relation between a first IP address corresponding to the first PDU session, a DNN identifier corresponding to the first PDU session and a strategy control session identifier of the first strategy control session; correspondingly, the first indication information may include: the first IP address and the DNN identification;

after receiving the establishment request, the SMF may determine, according to the correspondence, a policy control session identifier corresponding to the first IP address and the DNN identifier carried in the establishment request, and then determine that the policy control session identified by the policy control session identifier is the first policy control session.

The embodiment of the application provides another specific mode for determining the first policy control session through the association information and the first indication information, so that the flexibility of the scheme is improved.

Based on the first implementation manner of the first aspect of the embodiment of the present application, in a fourth implementation manner of the first aspect of the embodiment of the present application, the first corresponding relationship may include: the UE identification of the UE and the first PDU session identification of the first PDU session, and the corresponding relation between the first IP address corresponding to the first PDU session and the DNN identification corresponding to the first PDU session;

correspondingly, the first indication information may include: the UE identifier and the first PDU session identifier;

after receiving the establishment request, the SMF may determine, according to the correspondence, a first IP address and a DNN identifier corresponding to the UE identifier and the first PDU session identifier carried in the establishment request, and then determine that the policy control session corresponding to the first IP address and the DNN identifier is the first policy control session.

Based on the first aspect of the embodiment of the present application, in a fifth implementation manner of the first aspect of the embodiment of the present application, the association information of the policy control session may include: a first IP address corresponding to the first PDU session and a DNN identifier corresponding to the first PDU session;

correspondingly, the first indication information may include: the first IP address and DNN identification;

after receiving the establishment request, the SMF may know that the first IP address in the first indication information and the DNN identifier have an association relationship according to the association information, and then the SMF may determine that the policy control session corresponding to the first IP address and the DNN identifier is the first policy control session.

Based on the first aspect of the embodiment of the present application, in a sixth implementation manner of the first aspect of the embodiment of the present application, the association information of the policy control session may include: the UE identification of the UE and the DNN identification corresponding to the first PDU session are in corresponding relation with the first IP address corresponding to the first PDU session;

correspondingly, the first indication information may include: the UE identity and DNN identity;

after receiving the establishment request, the SMF determines, according to the correspondence, a first IP address corresponding to the UE identifier and the DNN identifier carried in the establishment request, and then determines that the policy control session identifier corresponding to the first IP address and the DNN identifier is the first policy control session identifier.

Based on the first aspect of the present application, or any one implementation manner of the first to sixth implementation manners of the first aspect, in a seventh implementation manner of the first aspect of the present application, the SMF may store the association information of the first policy control session before sending the PDU session reestablishment indication to the UE, and specifically, may store the association information only when the SMF determines that a preset PDU session release condition is satisfied.

The embodiment of the application provides a specific way for storing the associated information by the SMF, and the realizability of the scheme is improved.

Based on the third implementation manner or the fifth implementation manner of the first aspect of the present application, in an eighth implementation manner of the first aspect of the present application, the SMF may store association information of the first policy control session before sending the reestablishment instruction to the UE, and when the SMF determines that a preset PDU session release condition is satisfied, the SMF retains the association information, that is, does not release the association relationship indicated by the association information.

The embodiment of the application provides another specific way for storing the associated information by the SMF, so that the flexibility of the scheme is improved.

Based on the seventh or eighth implementation manner of the first aspect of the present application, in the ninth implementation manner of the first aspect of the present application, the preset PDU session release condition may be a session release caused by a TUPF change, and the reason for the TUPF change may specifically be that a location of the UE is changed or a TUPF transmission failure corresponding to the first PDU session.

The embodiment of the application provides a plurality of reasons for triggering the SMF to store the associated information, and improves the flexibility of the scheme.

Based on the first aspect of the present application, and any one implementation manner of the first to ninth implementation manners of the first aspect, in a tenth implementation manner of the first aspect of the present application, after receiving a request for establishing a second PDU session from a UE, the SMF may perform the following steps:

the SMF allocates a first IP address corresponding to the first PDU session for a second PDU session corresponding to the establishment request, namely allocates the same IP address as the first PDU session for the second PDU session.

The embodiment of the application provides a specific operation executed by the SMF in the process of establishing the second PDU session, and the realizability of the scheme is improved.

Based on the first aspect of the present application, and any one implementation manner of the first to ninth implementation manners of the first aspect, in an eleventh implementation manner of the first aspect of the present application, after receiving a request for establishing a second PDU session from a UE, the SMF may perform the following steps:

the SMF allocates a second IP address for a second PDU session corresponding to the establishment request, wherein the second IP address is different from a first IP address corresponding to the first PDU session, namely the SMF allocates an IP address different from the IP address of the first PDU session for the second PDU session;

correspondingly, after the SMF allocates the second IP address to the second PDU session, it needs to report an IP address change instruction to the PCF corresponding to the first policy control session to indicate the PCF that the IP address of the UE for data transmission is changed.

The embodiment of the application provides another specific operation executed by the SMF in the process of establishing the second PDU session, thereby improving the flexibility of the scheme.

A second aspect of the present embodiment provides another session processing method, including:

when a PDU session between a UE and a DN needs to be reselected and an SMF corresponding to the PDU session also needs to be reselected, SMF1 sends a release request of a first PDU session to the UE, and also sends a release instruction of a first policy control session to a PCF, where the first policy control session corresponds to a first AF session; after receiving the release instruction sent by the SMF1, the PCF releases the first policy control session according to the release instruction; meanwhile, after receiving a first PDU session release request sent by SMF1, the UE releases the first PDU session and sends a second PDU session establishment request to SMF 2; after receiving the second PDU session establishment request, SMF2 sends a second policy control session establishment request to the PCF, and carries the first indication information in the establishment request; after receiving the request for establishing the second policy control session sent by SMF2, the PCF determines the first AF session according to the first indication information and the association information of the first AF session carried in the request for establishing, and determines the first AF session as the AF session corresponding to the second policy control session corresponding to the request for establishing.

The PCF in the embodiment of the application can associate the original AF session with the newly-established policy control session, so that the AF session cannot be reestablished in the process of reestablishing the policy control session, and the signaling overhead brought by reestablishing the AF session is reduced.

Based on the second aspect of the present application, in a first implementation manner of the second aspect of the present application, the release instruction of the first policy control session received by the PCF may include second indication information, where the second indication information is used to indicate, to the PCF, that the SMF1 cannot continue to provide a service for the UE corresponding to the first policy control session.

In the embodiment of the application, the release instruction may carry the second indication information, so that the PCF may know the reason for releasing the first policy control session, and thus the PCF may perform other corresponding operations, thereby improving the flexibility of the scheme.

Based on the first implementation manner of the second aspect of the embodiment of the present application, in the second implementation manner of the second aspect of the embodiment of the present application, the second indication information may include: a first PDU session identification of the first PDU session. It should be understood that the second indication information may only include the first PDU session identifier, which is regarded as specific indication information, i.e., when the PCF receives the first PDU session identifier, it may be considered that SMF1 cannot continue to provide service to the UE corresponding to the first policy control session. The second indication information also includes other cause value information or specific indication information besides the first PDU session identifier, by which the PCF is indicated that SMF1 cannot continue to provide service for the UE corresponding to the first policy control session.

The embodiment of the application can inform the PCF of the reason for releasing the first policy control session in various ways, thereby improving the flexibility of the scheme.

Based on the second aspect of the present application, the first or second implementation manner of the second aspect, in a third implementation manner of the second aspect of the present application, the association information of the first AF session specifically may include: the UE identification of the UE corresponding to the first PDU session and the first session identification of the first PDU session, and the AF session identification of the first AF session; correspondingly, the first indication information may include: the UE identity and the first PDU session identity;

after receiving the establishment request sent by SMF2, the PCF may determine, according to the correspondence, an AF session identifier corresponding to the UE identifier and the first PDU session identifier in the establishment request, and determine that the AF session identified by the AF session identifier is the first AF session.

The embodiment of the application provides a mode for determining the first AF session according to the association information and the first indication information, and the realizability of the scheme is improved.

Based on the third implementation manner of the second aspect of the embodiment of the present application, in a fourth implementation manner of the second aspect of the embodiment of the present application, the PCF may store the association information after receiving the release instruction sent by the SMF1 and before receiving the establishment request sent by the SMF 2.

The embodiment of the application provides a specific way for storing the first corresponding relation, and the realizability of the scheme is improved.

Based on the second aspect of the present application or the first implementation manner of the second aspect, in a fifth implementation manner of the second aspect of the present application, the association information of the first AF session specifically may include: a first IP address corresponding to the first PDU session, a DNN identifier corresponding to the first PDU session and an AF identifier of the first AF session;

correspondingly, the first indication information may include the DNN identifier and the first IP address;

the PCF determines, after receiving the request for establishing the second policy control session sent by SMF2, the DNN identifier in the request for establishing and the AF identifier corresponding to the first IP address according to the association information, and then determines that the AF session identified by the AF identifier is the first AF session.

The embodiment of the application provides another way of determining the first AF session according to the association information and the first indication information, so that the flexibility of the scheme is improved.

Based on the fifth implementation manner of the second aspect of the embodiment of the present application, in the sixth implementation manner of the second aspect of the embodiment of the present application, the PCF may store the association information before receiving the release instruction sent by the SMF1, and then the PCF retains the association information after receiving the release instruction sent by the SMF2, that is, does not release the association information.

The embodiment of the application provides another specific way for storing the associated information, and the flexibility of the scheme is improved.

A third aspect of the embodiments of the present application provides a session processing method, including:

when meeting the preset PDU conversation release condition, the SMF sends a release request of a first PDU conversation to the UE, the release request comprises a reestablishment indication, the UE releases the first PDU conversation according to the release request after receiving the release request of the first PDU conversation, and sends a establishment request of a second PDU conversation after the first PDU conversation is released according to the reestablishment indication in the release request, the establishment request comprises first indication information, so that the SMF receiving the establishment request can associate a second PDU conversation with a first strategy control conversation according to the first indication information and pre-stored association information of the first strategy control conversation, or the SMF receiving the establishment request sends an establishment request of a second strategy control conversation to the PCF, and carries the first indication information in the establishment request.

In the embodiment of the application, after receiving the reestablishment indication, the UE sends a request for establishing the second PDU session to the SMF, and bears the first indication in the request, so that the SMF can associate the second PDU session with the first policy control session according to the first indication information, thereby avoiding reestablishing the policy control session and the AF session during the process of reestablishing the PDU session, and reducing signaling overhead.

Based on the third aspect of the present application, in a first implementation manner of the third aspect of the present application, the pre-stored association information of the first policy control session may include a UE identifier of the UE and a first PDU session identifier of the first PDU session, and a corresponding relationship between the policy control session identifier of the first policy control session; correspondingly, the first indication information may include the UE identity and a first PDU session identity of the first PDU session.

The embodiment of the application provides a specific mode which enables the SMF to determine the first policy control session, and the realizability of the scheme is improved.

Based on the first implementation manner of the third aspect of the present application, in a second implementation manner of the third aspect of the present application, before sending the request for establishing the second PDU session, the UE may allocate a PDU session identifier, which is the same as the first PDU session, to the second PDU session, that is, allocate a first PDU session identifier to the second PDU session, and then bear the first PDU session identifier allocated to the second PDU session in the first indication information.

The embodiment of the application provides a specific way for determining the first indication information, and the realizability of the scheme is improved.

Based on the first implementation manner of the third aspect of the present application, in the third implementation manner of the third aspect of the present application, before sending the request for establishing the second PDU session, the UE may allocate, to the second PDU session, a PDU session that is different from the first PDU session, that is, allocate, to the second PDU session, a second PDU session identifier, and simultaneously bear, in the first indication information, the PDU session identifier of the first PDU session, that is, the first PDU session identifier.

The embodiment of the application provides another specific way for determining the first indication information, and the flexibility of the scheme is improved.

Based on the third aspect of the present application, in a fourth implementation manner of the third aspect of the present application, the pre-stored association information of the first policy control session may include an IP address and a DNN identifier corresponding to the first PDU session, and a corresponding relationship between the policy control session identifier of the first policy control session; correspondingly, the first indication information may comprise the DNN identification and the first IP address.

The embodiment of the application provides another specific mode which can enable the SMF to determine the first policy control session, and the flexibility of the scheme is improved.

A fourth aspect of the present embodiment provides a session processing method, including:

when a first PDU session between the UE and the DN is released and a second PDU session between the UE and the DN needs to be established, the UE sends a request for establishing the second PDU session to the SMF, the SMF receives the request for establishing the second PDU session and executes corresponding operation to complete the establishment of the second PDU session, and in the process of establishing the second PDU session, the SMF sends a request for establishing a second policy control session to the PCF, wherein the request for establishing comprises the first indication information, so that the PCF can determine the first AF session according to the first indication information and the association information of the first AF session and associate the second policy control session with the first AF session, namely determine the AF session of the second policy control session as the first AF session.

In the embodiment of the application, after receiving the establishment request of the second PDU session, the SMF sends the establishment request of the second policy control session to the PCF, and carries the first indication in the establishment request, so that the PCF can associate the second policy control session with the first AF session according to the first indication information, thereby avoiding reestablishing the AF session in the process of reestablishing the PDU session and the policy control session, and reducing signaling overhead.

Based on the fourth aspect of the present application, in a first implementation manner of the fourth aspect of the present application, after receiving the establishment request of the second PDU session, the SMF parses the establishment request to obtain the UE identifier of the UE and the PDU session identifier of the second PDU session, and loads the PDU session identifier of the second PDU session and the UE identifier as the first indication information in the establishment request of the second policy control session. It should be appreciated that in this implementation, the PDU session identity of the second PDU session is UE assigned, which is the same as the PDU session identity of the first PDU session.

The embodiment of the application provides a specific way for the SMF to carry the first indication information, and the realizability of the scheme is improved.

Based on the fourth aspect of the present application, in a second implementation manner of the fourth aspect of the present application, after receiving the establishment request of the second PDU session, the SMF parses the establishment request to obtain the UE identifier of the UE and the PDU session identifier of the first PDU session, determines that the establishment request of the second PDU session is a reestablishment request, and bearers the UE identifier and the PDU session identifier of the first PDU session as the first indication information in the establishment request of the second policy control session.

In the embodiment of the application, the SMF can sense the second PDU session as the reestablishment request, so that the subsequent operation is facilitated, and the realizability of the scheme is improved.

Based on the fourth aspect of the present application, in a second implementation manner of the fourth aspect of the present application, after receiving the establishment request of the second PDU session, the SMF parses the establishment request to obtain the DNN identifier and the IP address corresponding to the first PDU session, determines that the establishment request of the second PDU session is a reestablishment request, and carries the DNN identifier and the IP address as first indication information in the establishment request of the first policy control session. And during the process of establishing the second PDU session, the SMF allocates the same IP address for the second PDU session as the first PDU session.

The embodiment of the application provides another specific way for the SMF to carry the first indication information, and the realizability of the scheme is improved.

A fifth aspect of the embodiments of the present application provides a session management function entity, where the session management function entity has a function of implementing a behavior of the session management function entity in the first aspect. The function can be realized by hardware, and can also be realized by executing corresponding software by hardware. The hardware or software includes one or more modules corresponding to the functions described above.

A sixth aspect of the present embodiment provides a policy control function entity, where the policy control function entity has a function of implementing a behavior of the policy control function entity in the second aspect. The function can be realized by hardware, and can also be realized by executing corresponding software by hardware. The hardware or software includes one or more modules corresponding to the functions described above.

A seventh aspect of embodiments of the present application provides a user equipment, where the user equipment has a function of implementing a behavior of the user equipment in the third aspect. The function can be realized by hardware, and can also be realized by executing corresponding software by hardware. The hardware or software includes one or more modules corresponding to the functions described above.

An eighth aspect of the embodiments of the present application provides a session management functional entity, where the session management functional entity has a function of implementing a behavior of the session management functional entity in the fourth aspect. The function can be realized by hardware, and can also be realized by executing corresponding software by hardware. The hardware or software includes one or more modules corresponding to the functions described above.

A ninth aspect of an embodiment of the present application provides a session processing system, including: the system comprises a policy control function entity, a first session management function entity and a second session management function entity;

wherein the first session management function entity is configured to: sending a PDU session reestablishment instruction to UE, and sending a release instruction of a first policy control session to a policy control functional entity, wherein the first policy control session corresponds to an AF session of a first application functional entity;

the second session management function entity is used for: receiving a second PDU session establishment request from the UE, and sending the establishment request of a second strategy control session to the strategy control functional entity, wherein the establishment request comprises first indication information;

the policy control function entity is configured to: and releasing the first policy control session according to the release instruction, determining the first AF session according to the first indication information and the association information of the first AF session, and determining the AF session corresponding to the second policy control session as the first AF session.

Based on the ninth aspect of the present application, in a first implementation manner of the ninth aspect of the present application, the release instruction includes second indication information, where the second indication information is used to indicate that the first session management functional entity of the policy control functional entity cannot continue to provide a service for the UE corresponding to the first policy control session.

A tenth aspect of the embodiments of the present application provides a computer storage medium, where the computer storage medium is used to store computer software instructions for the session management function entity, the policy control function entity, or the user equipment, and the computer software instructions include a program designed to execute the session management function entity, the policy control function entity, or the user equipment.

The session management functional entity may be as described in the fifth or eighth aspect above.

The policy control function may be as described in the preceding sixth aspect.

An eleventh aspect of embodiments of the present application provides a computer program product, where the computer program product includes computer software instructions, and the computer software instructions are loadable by a processor to implement a flow in a session processing method according to any one of the first to fourth aspects.

According to the technical scheme, the embodiment of the application has the following advantages:

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings used in the description of the embodiments will be briefly introduced below, and it is apparent that the drawings in the following description are only some embodiments of the present application.

Fig. 1 is a basic architecture diagram of a 5G communication network;

FIG. 2 is a flow chart of PDU session establishment;

FIG. 3 is a schematic diagram of an embodiment of a session processing method in the embodiment of the present application;

FIG. 4 is a schematic diagram of another embodiment of a session processing method in the embodiment of the present application;

FIG. 5 is a schematic diagram of another embodiment of a session processing method in the embodiment of the present application;

FIG. 6 is a schematic diagram of another embodiment of a session processing method in the embodiment of the present application;

FIG. 7 is a schematic diagram of another embodiment of a session processing method in the embodiment of the present application;

fig. 8 is a schematic diagram of an embodiment of a session management function entity in the embodiment of the present application;

FIG. 9 is a schematic diagram of an embodiment of a policy control function entity in an embodiment of the present application;

FIG. 10 is a schematic diagram of an embodiment of a session processing system in an embodiment of the present application;

fig. 11 is a schematic diagram of another embodiment of a session management function entity or a policy control function entity in the embodiment of the present application.

Detailed Description

The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only a part of the embodiments of the present application, and not all of the embodiments.

The terms "first," "second," "third," "fourth," and the like in the description and in the claims of the present application and in the above-described drawings (if any) are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used is interchangeable under appropriate circumstances such that the embodiments of the application described herein are, for example, capable of operation in sequences other than those illustrated or otherwise described herein. Furthermore, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed, but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.

The embodiment of the application provides a session processing method, a session processing device and a session processing system, which are used for reducing signaling overhead brought by reestablishing a policy control session and an AF session.

It should be understood that the embodiment of the present application may be applied to a 5G communication network architecture, and may also be applied to other network architectures, and the embodiment of the present application is not limited in particular. Referring to fig. 1, a brief description of the architecture of the 5G communication network follows, and fig. 1 is a basic architecture of the 5G communication network.

In the network architecture, an Application Function (AF) is mainly responsible for transferring the requirements of the Application side on the network side, such as Quality of Service (Qos) requirements.

A Policy Control Function (PCF) is mainly responsible for controlling policies such as charging rules, Qos, mobility, etc. of sessions and services.

The Session Management Function (SMF) is mainly responsible for Session association, execution of a control policy issued by the PCF, selection of the TUPF, allocation of an IP address of the UE, and other Session Management operations.

An access and Mobility Management Function (AMF) entity is mainly responsible for access and Mobility Management work such as Mobility Management, access authentication/authorization, and the like.

The User Plane termination Function entity (TUPF), which is an interface User Plane Function entity (UPF) of a data network, is mainly responsible for User Plane data forwarding, session/flow level-based accounting, bandwidth limitation, and other operations.

The Next Generation Access Network (NG AN) corresponds to a different Access Network in the 5G communication Network.

Next Generation User Equipment (NG UE) corresponds to a terminal in a 5G communication network.

It should be understood that the policy control function entity, the session management function entity, and the user plane termination function entity in fig. 1 are only names, and the names themselves do not limit the entities, for example, the "policy control function entity" may be replaced by a "policy control function" or other names; the "session management function entity" may also be replaced by a "session management function" or other names, and the policy control function entity may correspond to an entity that includes other functions besides the policy control function, the session management function entity may correspond to an entity that includes other functions besides the session management function, and the user plane termination function entity may correspond to an entity that includes other functions besides the user plane termination function, which is described in a unified manner herein and will not be described in detail below.

Any functional node or network element in the network architecture may be implemented by one entity device in a specific implementation, or may be implemented by a plurality of entity devices together, which is not specifically limited in this embodiment of the present application. That is, it can be understood that any one of the functional nodes or network elements in fig. 1 may be a logical functional module in an entity device, or may be a logical functional module composed of a plurality of entity devices, and this is not particularly limited in this embodiment of the present invention. Based on the above network architecture, after the UE attaches to the 5G network, the establishment of one or more PDU sessions and policy control sessions is triggered, and the procedure for establishing the PDU sessions and policy control sessions is briefly described below, with reference to fig. 2, the procedure for establishing the PDU sessions and policy control sessions includes:

UE sends PDU conversation to build request to AMF through AN;

AMF selects SMF providing service for PDU conversation corresponding to the PDU conversation establishing request, saves the corresponding relation between SMF and PDU conversation, and sends the PDU conversation establishing request to SMF;

SMF selects relative TUPF for UE, builds user transmission path through TUPF, and distributes IP address for UE, at the same time, SMF sends strategy control conversation building request to PCF;

in the process of establishing the policy control session, the SMF stores the corresponding relationship between the policy control session and the PDU session, and the AF session is also established between the AF and the PCF, and then the PCF stores the corresponding relationship between the AF session and the policy control session.

After the PDU session is established in the above manner or in another manner, if a certain condition is met, and the PDU session needs to be reestablished, the PDU session may be processed by using the session processing method in the embodiment of the present application, specifically, referring to fig. 3, an embodiment of the session processing method in the embodiment of the present application includes:

301. SMF sends PDU conversation reestablishing indication to UE;

when the SMF determines that the PDU session between the UE and the DN needs to be reestablished, the SMF sends a PDU session reestablishment instruction to the UE, wherein the PDU session reestablishment instruction is used for indicating the UE to initiate a new PDU session establishment request, namely an establishment request of a second PDU session, after the first PDU session is released. It should be understood that the first and second PDU sessions refer to PDU sessions that are both between the same UE and DN.

302. The SMF receives a request for establishing a second PDU session from the UE;

and the UE receives a PDU session reestablishment instruction sent by the SMF, and sends a second PDU session establishment request after the first PDU session is released, and the SMF receives the establishment request which contains the first indication information. It should be understood that, in the embodiment of the present application, the establishment request received by the SMF means that the SMF receives a message having a function of requesting to establish the second PDU session, that is, the SMF receives a message that may be an establishment request message, a session management service message, or another message that can request the SMF to establish the second PDU session.

For example, after the first PDU session is released, the UE sends a request message for establishing a second PDU session, the AMF receives the request message, determines that the receiving party is the SMF according to the request message, and then the AMF sends a session management request message or a session management service message to the SMF, where the session management request message or the session management service message is used to request the SMF to establish the second PDU session, and the session management request message or the session management service message includes the first indication information. It should be understood that the SMF may receive the establishment request in other ways besides the above, and is not limited herein.

303. The SMF determines a first policy control session according to the first indication information in the establishment request and the association information of the first policy control session, and determines a policy control session corresponding to the second PDU session as the first policy control session.

The SMF determines a first policy control session according to the first indication information in the establishment request and the association information of the first policy control session, and associates the first policy control session with a second PDU session, that is, determines the policy control session corresponding to the second PDU session as the first policy control session.

In this embodiment of the present application, after the SMF sends the PDU session reestablishment indication to the UE, the SMF receives a second PDU session reestablishment request sent by the UE, where the reestablishment request includes the first indication information, and then the SMF may determine the first policy control session according to the first indication information and the association information of the first policy control session, and determine the first policy control session as the policy control session corresponding to the second PDU session. Therefore, the SMF in the embodiment of the present application can associate the original policy control session with the newly-established PDU session, so that the policy control session is not re-established in the process of re-establishing the PDU session, thereby avoiding the release of the AF session, and reducing the signaling overhead brought by re-establishing the policy control session and the re-establishing the AF session.

Based on the above embodiment corresponding to fig. 3, it can be known that the association information of the first policy control session is stored by the SMF before receiving the establishment request of the second PDU session, specifically, the SMF may trigger the storage operation under different conditions, and as described in detail below with an embodiment, referring to fig. 4, another embodiment of the session processing method in this embodiment of the present application includes:

401. the SMF stores the associated information of the first policy control session;

after the first PDU session between the UE and the DN is established, when the first PDU session meets a preset session release condition, the SMF stores the associated information of the first strategy control session corresponding to the first PDU session.

Specifically, the association information of the first policy control session may be a corresponding relationship between the first PDU session and the first policy control session, and the first PDU session and the first policy control session may be identified in multiple ways, so that the SMF may store information capable of identifying the first PDU session and information capable of identifying the first policy control session, which are described in the following table 1:

	first PDU session	First policy control session
			Mode 1	UE identity, first PDU session identity	Policy control session identification
Mode 2	First IP Address, DNN identification	Policy control session identification
			Mode 3	UE identity, first PDU session identity	First IP Address, DNN identification

TABLE 1

The UE identification refers to the identification of the UE corresponding to the first PDU session, the first PDU session identification refers to the PDU session identification of the first PDU session, the first IP address refers to the IP address corresponding to the first PDU session, the DNN identification refers to the identification of the DNN corresponding to the first PDU session, and the strategy control session identification refers to the session identification of the first strategy control session.

In the mode 1, the correspondence between the first PDU session and the first policy control session is specifically: the UE and the first PDU session identifier are used for identifying the first PDU session, and the strategy control session identifier is used for identifying the first strategy control session.

In the mode 2, the correspondence between the first PDU session and the first policy control session is specifically: the system comprises a first IP address and a DNN identifier and a corresponding relation between policy control session identifiers, wherein the first IP address and the DNN identifier are used for identifying a first PDU session, and the policy control session identifiers are used for identifying a first policy control session.

In the manner 3, the correspondence between the first PDU session and the first policy control session is specifically: the system comprises a first PDU session identifier, a UE identifier and a corresponding relation between the first PDU session identifier and a first IP address and a DNN identifier, wherein the UE identifier and the first PDU session identifier are used for identifying a first PDU session, and the first IP address and the DNN identifier are used for identifying a first policy control session.

The associated information may be, in addition to the corresponding relationship between the first PDU session and the first policy control session, PDU session information capable of identifying the first policy control session, which is specifically referred to as the following two ways:

in the mode 4, the association information of the first policy control session specifically includes: a first IP address corresponding to the first PDU session and a DNN identifier corresponding to the first PDU session;

in the mode 5, the association information of the first policy control session specifically includes: and the corresponding relation between the DNN identification corresponding to the first PDU session and the UE identification corresponding to the first PDU session and the first IP address corresponding to the first PDU session.

It should be noted that the association information described in the above-mentioned manner 2 and manner 4 may be stored by the SMF in the process of establishing the first PDU session, and when the first PDU session meets the preset PDU session release condition, the SMF may release the corresponding relationship and then store the corresponding relationship again, or may directly retain the corresponding relationship, that is, the corresponding relationship is not released.

It should be further noted that, in this embodiment of the application, the PDU session release condition is preset by a user or a system, and specifically, the PDU session release condition may be a change in a location of a UE corresponding to a first PDU session, or a failure of a TUPF corresponding to the first PDU session, or another condition that the TUPF needs to be reselected, which is not limited herein.

It should be noted that, in addition to the above 5 modes, the related information may be other information, and is not limited herein.

402. SMF sends PDU conversation reestablishing indication to UE;

when the first PDU session meets the preset session release condition and the SMF stores the association information of the first policy control session, the SMF sends a PDU session reestablishment instruction to the UE, wherein the PDU session reestablishment instruction is used for indicating the UE to initiate a new PDU session establishment request after the first PDU session is released, namely the establishment request of a second PDU session between the UE and the DN.

403. The SMF receives a request for establishing a second PDU session sent by the UE;

For example, after the first PDU session is released, the UE sends a request message for establishing a second PDU session, the AMF receives the request message, determines that the receiving party is the SMF according to the request message, and then the AMF sends a session management request message or a session management service message to the SMF, where the session management request message or the session management service message is used to request the SMF to establish the second PDU session, and the session management request message or the session management service message includes the first indication information.

It should be understood that the SMF may receive the establishment request in other ways besides the above, and is not limited herein.

It should be noted that, corresponding to the different association information, the first indication information carried by the establishment request is also different, specifically:

corresponding to the mode 1 in the step 401, the first indication information is specifically: a first PDU session identifier and a UE identifier;

corresponding to the mode 2, 3 or 4 in the step 401, the first indication information is specifically: a first IP address and a DNN identification corresponding to the first PDU session;

corresponding to the mode 5 in the step 401, the first indication information is specifically: and the DNN identification and the UE identification corresponding to the first PDU session.

It should be further noted that, before sending the request for establishing the second PDU session, the UE may assign a PDU session identifier to the second PDU session, where the PDU session identifier may be the same as or different from the PDU session identifier of the first PDU session. That is, for the first indication information: the first PDU session identifier may be a PDU session identifier of the second PDU session, or may be a PDU session identifier of the first PDU session.

404. And the SMF determines a first policy control session according to the first indication information and the association information of the first policy control session, and determines the policy control session corresponding to the second PDU session as the first policy control session.

Specifically, corresponding to the mode 1 in the above step 401, the SMF may determine the first policy control session by: the SMF determines a policy control session identifier corresponding to the UE identifier and the first PDU session identifier carried in the establishment request according to the correspondence relationship in the above mode 1, where the policy control session identified by the policy control session identifier is the first policy control session.

Corresponding to mode 2 in step 402 above, the SMF may determine the first policy control session by: the SMF determines a policy control session identifier corresponding to the first IP identifier and the DNN identifier carried in the establishment request according to the correspondence relationship in the above-described manner 2, where the policy control session identified by the policy control session identifier is the first policy control session.

Corresponding to mode 3 in step 402 above, the SMF may determine the first policy control session by: the SMF determines, according to the correspondence relationship in the above-described manner 3, a first IP address and a DNN identifier corresponding to the UE identifier and the first PDU session identifier carried in the establishment request, where the policy control session corresponding to the first IP address and the DNN identifier is the first policy control session.

Corresponding to mode 4 in step 402 above, the SMF may determine the first policy control session by: the SMF determines that the SMF has the first policy control session identified by the first IP address and the DNN identifier according to the association information in the manner 4, and then the SMF determines that the policy control session corresponding to the first IP address and the DNN identifier carried in the establishment request is the first policy control session.

Corresponding to mode 5 in step 402 above, the SMF may determine the first policy control session by: the SMF determines, according to the correspondence relationship in the above-described manner 5, an IP address, that is, a first IP address, corresponding to the DNN identifier and the UE identifier carried in the establishment request, and a policy control session corresponding to the first IP address and the DNN identifier is a first policy control session.

It should be understood that the SMF may determine the first policy control session in other ways besides the above-mentioned way, and is not limited herein.

It should be noted that, in this embodiment of the application, after receiving the establishment request of the second PDU session sent by the UE, the SMF may further perform the following steps while performing step 404 above:

the SMF selects a new TUPF for the second PDU session and assigns an IP address for the second PDU session, wherein the IP address is used for the UE to use for data transmission with the DN and the TUPF is used to establish a new user plane path. Specifically, the IP address may be a first IP address, i.e., the same IP address as the IP address of the first PDU session, or a second IP address, i.e., an IP address different from the IP address of the first PDU session.

When the SMF allocates the IP address for the second PDU session to be different from the IP address for the first PDU session, the SMF reports an IP address change instruction to the PCF corresponding to the first policy control session after allocating the IP address, wherein the IP address change instruction is used for indicating the PCF UE to change the IP address for data transmission.

Optionally, in this embodiment of the present application, after the SMF selects a new TUPF for the second PDU session and allocates an IP address, when the second PDU session establishment is completed, the SMF may further return a session establishment response to the UE, where the session establishment response is used to indicate that the UE completes the second PDU session establishment.

Secondly, the embodiment of the application provides a plurality of ways for storing the association information and determining the first policy control session by the SMF, thereby improving the flexibility of the scheme.

It should be understood that after the PDU session is established, in some scenarios, the PDU session needs to be reestablished, and the SMF corresponding to the PDU session needs to be reselected, at this time, another session processing method provided in the embodiment of the present application may be used for processing, and specifically, referring to fig. 5, another embodiment of the session management method in the embodiment of the present application includes:

501. the PCF receives a release instruction of the first policy control session sent by the SMF 1;

when a PDU session between the UE and the DN needs to be reestablished and an SMF corresponding to the PDU session needs to be reselected, the SMF1 sends a PDU session reestablishment indication to the UE, where the PDU session reestablishment indication is used to indicate that the UE initiates a new PDU session establishment request, that is, an establishment request of a second PDU session, after the release of the first PDU session is completed. At the same time, SMF1 also sends a release order for the first policy control session to the PCF, which corresponds to the first AF session. The PCF receives the release order sent by SMF 1.

502. The PCF releases the first strategy control conversation according to the release instruction;

after receiving the release instruction sent by SMF1, the PCF releases the first policy control session according to the release instruction. Further, the PCF may return a response message to the SMF1 after the first policy control session release is completed, the response message indicating that the SMF1 first policy control session release is completed.

503. The PCF receives a request for establishing a second policy control session sent by the SMF 2;

after receiving the PDU session reestablishment indication sent by SMF1, the UE sends a second PDU session establishment request to SMF2 according to the PDU session reestablishment indication after the first PDU session is released, and the second PDU session establishment request carries the first indication information. After receiving the establishment request sent by the UE, the SMF2 executes corresponding operations to complete establishment of the second PDU session, and during the establishment of the second PDU session, the SMF2 also sends the establishment request of the second policy control session to the PCF, and the establishment request carries the first indication information. The PCF receives the setup request.

504. And the PCF determines the first AF session according to the first indication information in the establishment request and the correlation information of the first AF session, and determines the AF session corresponding to the second policy control session as the first AF session.

After receiving the establishment request sent by SMF2, the PCF executes corresponding operations to complete establishment of the second policy control session, and during establishment of the second policy control session, the PCF further determines the first AF session according to the first indication information and the association information of the first AF in the establishment request, and associates the second policy control session with the first AF session, that is, determines the AF session corresponding to the second policy control session as the first AF session.

In this embodiment of the present application, the request for establishing the second policy control session received by the PCF includes the first indication information, and the PCF may determine the first AF session according to the first indication information and the pre-stored association information of the first AF session, and determine that the AF session corresponding to the second policy control session is the first AF session. Therefore, the PCF in the embodiment of the present application can associate the original AF session with the newly established policy control session, so that the AF session is not re-established in the process of re-establishing the policy control session, and signaling overhead caused by re-establishing the AF session is reduced.

When initiating a PDU session establishment request to the SMF, the UE carries its own UE identity and corresponding DNN identity, and also carries a PDU session identity allocated by the UE for the PDU session corresponding to the initiated PDU session establishment request. The SMF also reports the received UE identifier and DNN identifier to the PCF when initiating a policy control session establishment request, and the SMF may or may not report the PDU session identifier of the PDU session, and as for these two scenarios, an interactive embodiment is used to describe in detail another session processing method provided in the embodiments of the present application, respectively:

when SMF initiates a strategy control session establishment request, PDU session identification of PDU session is not reported;

referring to fig. 6, another embodiment of a session processing method in the embodiment of the present application includes:

601. SMF1 sends PDU conversation reestablishing indication to UE, and sends releasing instruction of first strategy control conversation to PCF;

when the first PDU session meets the preset session release condition, the SMF1 sends a release instruction of the first PDU session to the UE, wherein the release instruction comprises a PDU session reestablishment instruction used for indicating the UE to initiate a new PDU session establishment request after the first PDU session is released, and the first PDU session corresponds to the first policy control session.

At the same time, the SMF1 sends a release order for the first policy control session to the PCF, the first policy control session corresponding to the first AF session, the release order including second indication information that may be used to indicate that the PCF that the SMF1 cannot continue to provide service to the UE corresponding to the first policy control session. Specifically, the second indication information may indicate the PCF through specific cause value information, that is, the cause that the SMF1 cannot provide the service to the UE is carried in the second indication information, or may indicate the PCF through specific indication information, that is, a specific indication information is defined with the PCF, and when the PCF receives the specific indication information, it is determined that the SMF1 cannot continue to provide the service to the UE.

It should be understood that, when the second indication information indicates the PCF through the cause value information, the second indication information may or may not include, in addition to the cause value information, the first PDU session identifier of the first PDU session, and is not limited herein. When the second indication information indicates the PCF through specific indication information, the specific indication information may be the first PDU session identifier, or may be other specific indication information, which is not limited herein.

It should also be understood that, in the embodiment of the present application, the reason why the SMF1 cannot continue to provide the service to the UE may specifically include: the location of the UE corresponding to the first PDU session changes, the TUPF corresponding to the first PDU session fails, or the SMF1 is overloaded, or other reasons, which are not limited herein.

602. The PCF releases the first strategy control conversation according to the release instruction;

after receiving the release instruction of the first policy control session sent by the SMF1, the PCF releases the first policy control session according to the release instruction, and knows that the SMF1 cannot continue to provide service for the UE according to the second indication information in the release instruction, and the PCF releases the first policy control session and simultaneously reserves the first AF session.

It should be understood that the PCF may store the association information of the first AF session in the mode 2 in the following table 2 during the process of establishing the first policy control session, and after receiving the release instruction, the PCF may release the first policy control session and simultaneously retain the association information according to the indication in the second indication information, that is, may not release the association information, or may release the association information, and then store the association information according to the indication in the second indication information in the mode 1 or the mode 2 in the following table 2,

	first PDU session	First AF session
			Mode 1	UE identity, first PDU session identity	AF session identification
Mode 2	First IP Address, DNN identification	AF session identification

TABLE 2

The UE identifier refers to an identifier of a UE corresponding to a first PDU session, the first PDU session identifier refers to a PDU session identifier of the first PDU session, the first IP address refers to an IP address corresponding to the first PDU session, the DNN identifier refers to an identifier of a DNN corresponding to the first PDU session, and the AF session identifier refers to a session identifier of a first AF session.

In the mode 1, the association information of the first AF session specifically includes: the UE identification and the first PDU session are in corresponding relation with the AF session identification; the UE identifier and the first PDU session identifier are used for identifying the first PDU session, and the AF session identifier is used for identifying the first AF session.

In the method 2, the association information of the first AF session specifically includes: the first IP address and the DNN identification correspond to the AF session; the first IP address and the DNN identifier are used for identifying the first PDU session, and the AF session identifier is used for identifying the first AF session.

It should be understood that the session identifier of the first PDU in the above mode 1 may be obtained by the PCF by parsing the second indication information, or may be obtained by the PCF during the establishment of the first policy control session. The PCF may also be obtained by other means, and is not limited herein in particular.

603. The UE sends a second PDU session setup request to SMF 2;

after receiving the release instruction of the first PDU session sent by the SMF1, the UE executes corresponding operations to complete the release of the first PDU session, and allocates a PDU session identifier for the second PDU session according to the PDU session reestablishment instruction in the release instruction, where the PDU session identifier may be the same as or different from the PDU session identifier of the first PDD session, and the specific details are not limited herein.

Then UE sends a second PDU session establishment request to SMF2, where the establishment request carries, in addition to UE id, DNN id and PDU session id of the second PDU session, the following indication information: a PDU session identification of the first PDU session (first PDU session identification) or a first IP address corresponding to the first PDU session.

604. SMF2 sends a request to the PCF to establish the second policy control session;

after receiving the second PDU session establishment request sent by the UE, SMF2 sends a second policy control session establishment request to the PCF during the second PDU session establishment process, where the establishment request includes the first indication information.

Specifically, if the second PDU session establishment request includes indication information other than the UE id, the DNN id, and the PDU session id of the second PDU session, SMF2 determines that the second PDU session establishment request is a reestablishment request, and SMF2 carries the indication information in the establishment request of the second policy control session, and also carries the UE id and the DNN id in the establishment request.

If the indication information carried by the UE in 603 is the first PDU session identifier of the first PDU session, the request for establishing the second policy control session may include the first PDU session identifier and the UE identifier, and at this time, the first indication information indicates the first PDU session identifier and the UE identifier.

If the indication information carried by the UE in 603 is the first IP address corresponding to the first PDU session, the request for establishing the second policy control session may include the first IP address and the DNN identifier, where the first IP address and the DNN identifier belong to the first indication information in the embodiment of the present application, and at this time, the first indication information refers to the first IP address and the DNN identifier.

In addition, if the indication information carried by the UE in 603 is the first IP address corresponding to the first PDU session, the SMF needs to allocate the first IP address to the second PDU session in the process of establishing the second PDU session, that is, needs to allocate the same IP address as the first PDU session to the second PDU session.

605. And the PCF determines the first AF session according to the first indication information in the establishment request and the correlation information of the AF session, and determines the AF session corresponding to the second strategy control session as the first AF session.

After receiving the request for establishing the second policy control session, the PCF determines, in the process of establishing the second policy control session, the first AF session according to the first indication information in the request for establishing and the association information of the AF session, and associates the first AF session with the second policy control session, that is, determines the AF session corresponding to the second policy control session as the first AF session.

Corresponding to the correspondence stored in the mode 1 in the above step 602, the first indication information includes: the UE identifier and the first PDU session identifier, at this time, the PCF determines the first AF session by the following method:

the PCF determines the AF session identifier corresponding to the UE identifier and the first PDU session identifier according to the correspondence stored in the mode 1, and the AF session identified by the AF session identifier is the first AF session.

Corresponding to the correspondence stored in the above-mentioned method 2 in step 602, the first indication information includes: the DNN identifies a first IP address. At this time, the PCF determines the first AF session by:

the PCF determines the AF session identifier corresponding to the DNN identifier and the first IP address according to the correspondence stored in the mode 2, and the AF session identified by the AF session identifier is the first AF session.

Optionally, in this embodiment of the present application, after the second policy control session is established, the PCF may return a response message to SMF2 to inform SMF2 that the second policy control session is established.

Optionally, in this embodiment, after the second PDU session is established, the SMF2 further returns a response message to the UE to inform the UE that the second PDU session is established.

In this embodiment of the present application, the request for establishing the second policy control session received by the PCF includes the first indication information, and the PCF may determine the first AF session according to the first indication information and the association information of the AF session, and determine that the AF session corresponding to the second policy control session is the first AF session. Therefore, the PCF in the embodiment of the present application can associate the original AF session with the newly established policy control session, so that the AF session is not re-established in the process of re-establishing the policy control session, and signaling overhead caused by re-establishing the AF session is reduced.

Secondly, the SMF in the embodiment of the application can sense PDU session reestablishment, so that the SMF can conveniently execute subsequent operations, and the flexibility of the scheme is improved.

The embodiment of the present application provides multiple ways for the PCF to determine the first AF session, thereby further improving the flexibility of the scheme.

And secondly, when the SMF initiates a policy control session establishment request, reporting the PDU session identification of the PDU session.

Referring to fig. 7, another embodiment of a session processing method in the embodiment of the present application includes:

701. SMF1 sends PDU conversation reestablishing indication to UE, and sends releasing instruction of first strategy control conversation to PCF;

step 701 in this embodiment is similar to step 601 in the embodiment shown in fig. 6, and is not described here again.

702. The PCF releases the first strategy control session according to the release instruction and stores the associated information of the first AF session;

after receiving a release instruction of the first policy control session sent by the SMF1, the PCF releases the first policy control session according to the release instruction, and knows that the SMF1 cannot continue to provide services for the UE according to the second indication information in the release instruction, and then the PCF releases the first policy control session and stores the association information of the first AF session in the following manner: and the PCF stores the UE identification and the first PDU session identification of the first PDU session and the corresponding relation between the AF session identification of the first AF session. The first PDU session identifier and the UE identifier are used for identifying the first PDU session, and the AF session identifier is used for identifying the first AF session.

703. The UE distributes a first PDU session identifier for a second PDU session according to the PDU session reestablishment indication and sends a second PDU session establishment request to the SMF 2;

after receiving the release instruction of the first PDU session sent by SMF1, the UE performs corresponding operations to complete the release of the first PDU session, and allocates the same PDU session identifier as the first PDU session to the second PDU session, that is, the first PDU session identifier, according to the PDU session reestablishment indication in the release instruction.

Then, the UE sends a request for establishing the second PDU session to SMF2, where the request carries the UE identity, the DNN identity, and a PDU session identity (first PDU session identity) of the second PDU session.

704. SMF2 sends a request to the PCF to establish the second policy control session;

after receiving the second PDU session establishment request sent by the UE, during the second PDU session establishment process, SMF2 sends the establishment request of the second policy control session to the PCF, and carries the UE id and the PDU session id of the second PDU session to the establishment request, where the first indication information indicates the PDU session id (the first PDU session id) and the UE id of the second PDU session.

705. And the PCF determines the first AF session according to the first indication information and the correlation information, and determines the AF session corresponding to the second strategy control session as the first AF session.

After receiving the request for establishing the second policy control session, the PCF determines the first AF session in the process of establishing the second policy control session by:

and the PCF determines an AF session identifier corresponding to the UE identifier and the first PDU session identifier according to the AF association information, wherein the AF session identified by the AF session identifier is the first AF session.

After determining the first AF session, the PCF associates the first AF session with the second policy control session, that is, determines the AF session corresponding to the second policy control session as the first AF session.

In this embodiment of the present application, the request for establishing the second policy control session received by the PCF includes the first indication information, and the PCF may determine the first AF session according to the first indication information and the pre-stored association information, and determine that the AF session corresponding to the second policy control session is the first AF session. Therefore, the PCF in the embodiment of the present application can associate the original AF session with the newly established policy control session, so that the AF session is not re-established in the process of re-establishing the policy control session, and signaling overhead caused by re-establishing the AF session is reduced.

Secondly, when the SMF2 of the embodiment of the present application sends the request for establishing the second policy control session to the PCF, no additional indication information may be carried, thereby reducing the signaling overhead in the process.

The above describes the session processing method in the embodiment of the present application, and a description is given below of the session management functional entity in the embodiment of the present application:

referring to fig. 8, an embodiment of a session management function entity in the embodiment of the present application includes:

a sending module 801, configured to send a PDU session reestablishment indication to a user equipment UE;

a receiving module 802, configured to receive a setup request of a second packet data unit PDU session from a UE, where the setup request includes first indication information;

the determining module 803 is configured to determine the first policy control session according to the first indication information and the association information of the first policy control session received by the receiving module 802, and determine the policy control session corresponding to the second PDU session as the first policy control session.

In this embodiment of the present application, after the sending module 801 sends a PDU session reestablishment indication to the UE, the receiving module 802 receives a second PDU session reestablishment request from the UE, where the reestablishment request includes first indication information, and then the determining module 803 may determine a first policy control session according to the first indication information and association information of the first policy control session, and determine the first policy control session as a policy control session corresponding to the second PDU session. Therefore, the session management functional entity in the embodiment of the application can associate the original policy control session with the newly-established PDU session, so that the policy control session is not reestablished in the process of reestablishing the PDU session, the release of the AF session is avoided, and the signaling overhead brought by reestablishing the policy control session and reestablishing the AF session is reduced.

It should be understood that, based on the above-mentioned embodiment corresponding to fig. 8, in another embodiment of the session management function entity provided in the embodiment of the present application, the association information may include a first correspondence between the first PDU session and the first policy control session.

The first PDU session and the first policy control session in the first corresponding relationship may be identified by different information, and based on the difference of the identification information and the content of the first indication information, the determining module 803 determines that the first policy control session is different in manner, and the following describes several cases:

optionally, the first correspondence relationship includes: the UE identification of the UE and the first PDU session identification of the first PDU session are in corresponding relation with the strategy control session identification of the first strategy control session;

the first indication information comprises a UE identification and a first PDU session identification;

the determining module 803 is configured to, when determining the first policy control session according to the first indication information and the association information of the first policy control session received by the receiving module 802, specifically include:

and determining a first policy control session corresponding to the UE identifier and the policy control session identifier corresponding to the first PDU session according to the corresponding relation.

Optionally, the first correspondence relationship includes: the corresponding relation between a first inter-network Internet Protocol (IP) address corresponding to the first Protocol Data Unit (PDU) session, a Data Network Name (DNN) identifier corresponding to the first PDU session and a policy control session identifier of the first policy control session;

the first indication information includes: a first IP address and a DNN identification;

and determining a first policy control session corresponding to the policy control session identifier corresponding to the first IP address and the DNN identifier according to the corresponding relation.

Optionally, the first correspondence relationship includes: the UE identification of the UE and the first PDU session identification of the first PDU session, and the corresponding relation between the first IP address corresponding to the first PDU session and the DNN identification corresponding to the first PDU session;

the determining module 803 is configured to, when determining the first policy control session according to the first indication information and the association information of the first policy control session received by the receiving module 802, specifically include: and determining the strategy control session corresponding to the first IP address and the DNN corresponding to the UE identifier and the first PDU session identifier as a first strategy control session according to the corresponding relation.

In this embodiment of the present application, the determining module 803 may determine the first policy control session in multiple ways, so as to improve flexibility of the scheme.

It should be understood that based on the above-mentioned embodiment corresponding to fig. 8, in another embodiment of the session management function entity provided in the embodiment of the present application, the association information includes: a first IP address corresponding to the first PDU session and a DNN identifier corresponding to the first PDU session; the first indication information includes: a first IP address and a DNN identifier;

at this time, when the determining module 803 is configured to determine the first policy control session according to the first indication information and the association information of the first policy control session received by the receiving module 802, the determining module specifically includes: and determining the policy control session corresponding to the first IP address and the DNN identification as a first policy control session according to the corresponding relation.

The embodiment of the present application provides another way for determining the first policy control session by the determining module 803, so that the flexibility of the scheme is improved.

It should be understood that based on the above-mentioned embodiment corresponding to fig. 8, in another embodiment of the session management function entity provided in the embodiment of the present application, the association information includes: the UE identification of the UE and the DNN identification corresponding to the first PDU session are in corresponding relation with the first IP address corresponding to the first PDU session; the first indication information comprises a UE identifier and a DNN identifier;

at this time, when the determining module 803 is configured to determine the first policy control session according to the first indication information and the association information of the first policy control session received by the receiving module 802, the determining module specifically includes: and determining the first IP address corresponding to the UE identifier and the DNN identifier and the policy control session corresponding to the DNN identifier as a first policy control session according to the corresponding relation.

In another embodiment of the session management functional entity provided in the embodiment of the present application, the session management functional entity further includes:

a storage module 804, configured to store association information of the first policy control session when it is determined that a preset PDU session release condition is satisfied.

Optionally, the preset PDU session release condition includes: the location of the UE changes or the TUPF corresponding to the first PDU session fails.

The embodiment of the application provides a specific way for storing the associated information, and the realizability of the scheme is improved.

a first allocating module 805, configured to allocate a first IP address corresponding to a first PDU session for a second PDU session;

or the like, or, alternatively,

a second allocating module 806, configured to allocate a second IP address for the second PDU session, where the second IP address is different from the first IP address corresponding to the first PDU session;

at this time, the sending module 801 is further configured to: and reporting an IP address change instruction to a policy control function entity (PCF) corresponding to the first policy control session, wherein the IP address change instruction is used for indicating the PCF that the IP address of the UE for data transmission is changed.

In the embodiment corresponding to fig. 8, the flow executed by each module in the session management functional entity is similar to the method flow described in the embodiments shown in fig. 3 to fig. 4, and is not described again here.

With reference to fig. 9, the session management functional entity in the embodiment of the present application is described above, and a policy control functional entity in the present application is described below, where an embodiment of the policy control functional entity in the embodiment of the present application includes:

a first receiving module 901, configured to receive a release instruction of a first policy control session sent by a first session management function entity, where the first policy control session corresponds to an AF session of a first application function entity;

a releasing module 902, configured to release the first policy control session according to the release instruction received by the first receiving module 901;

a second receiving module 903, configured to receive a request for establishing a second policy control session, where the request for establishing the second policy control session includes first indication information, where the request for establishing the second policy control session is sent by a second session management function entity;

a determining module 904, configured to determine the first AF session according to the first indication information and the association information of the first AF session received by the second receiving module 903, and determine that the AF session corresponding to the second policy control session is the first AF session.

In this embodiment of the application, the request for establishing the second policy control session received by the second receiving module 902 includes first indication information, and the determining module 903 may determine the first AF session according to the first indication information and pre-stored association information of the AF, and determine that the AF session corresponding to the second policy control session is the first AF session. Therefore, the PCF in the embodiment of the present application can associate the original AF session with the newly established policy control session, so that the AF session is not re-established in the process of re-establishing the policy control session, and signaling overhead caused by re-establishing the AF session is reduced.

Based on the embodiment corresponding to fig. 9, in other embodiments of the policy control function entity provided in the present application, the release instruction may include second indication information, where the second indication information is used to indicate that the policy control function entity cannot continue to provide services for the UE corresponding to the first policy control session. Specifically, the second indication information may include a first PDU session identifier of the first PDU session, or other information, which is not limited herein.

Optionally, in this embodiment, the association information of the AF session may include: the corresponding relation between the UE identification corresponding to the first PDU session, the first PDU session identification of the first PDU session and the AF session identification of the first AF session; the first indication information may include: UE identification and first PDU conversation identification.

Based on the above correspondence, the policy control function entity may further include: and the storage module is used for storing the corresponding relation.

The determining module is configured to, when determining the first AF session according to the first indication information and the association information of the first AF session received by the second receiving module 903, specifically include: and determining the UE identifier and the first AF session corresponding to the AF session identifier corresponding to the first PDU session identifier according to the corresponding relation.

Optionally, in this embodiment, the association information of the AF session may include: and the corresponding relation between the first inter-network Internet Protocol (IP) address corresponding to the first PDU session, the Data Network Name (DNN) identification corresponding to the first PDU session and the AF session identification of the first AF session. Correspondingly, in this embodiment, the first indication information includes: the DNN identifies a first IP address.

Based on the above correspondence, when the determining module 904 is configured to determine the first AF session according to the first indication information and the association information of the first AF session received by the second receiving module 903, the determining module specifically includes: and determining the DNN identifier and the first AF session corresponding to the AF session identifier corresponding to the first IP address according to the corresponding relation.

The embodiment of the application provides a plurality of specific modes for determining the first AF session by the determining module, and the flexibility of the scheme is improved.

In the embodiment corresponding to fig. 9, the flow executed by each module in the policy control function entity is similar to the method flow described in the embodiments shown in fig. 5 to fig. 7, and is not repeated here.

With reference to fig. 10, an embodiment of a session processing system in an embodiment of the present application includes: a policy control function 1001, a first session management function 1002 and a second session management function 1003;

the first session management functional entity 1002 is configured to: sending a PDU session reestablishment instruction to UE, and sending a release instruction of a first policy control session to a policy control functional entity, wherein the first policy control session corresponds to an AF session of a first application functional entity;

the second session management function entity 1003 is configured to: receiving a second PDU session establishment request from the UE, and sending the establishment request of a second strategy control session to the strategy control functional entity, wherein the establishment request comprises first indication information;

the policy control function 1001 is configured to: and releasing the first policy control session according to the release instruction, determining the first AF session according to the first indication information and the association information of the first AF session, and determining the AF session corresponding to the second policy control session as the first AF session.

Optionally, the release instruction includes second indication information, where the second indication information is used to indicate that the policy control functional entity 1201 and the first session management functional entity 1002 cannot continue to provide services for the UE corresponding to the first policy control session.

Optionally, the second session management functional entity 1003 is specifically configured to:

taking a PDU session identifier of a second PDU session and a UE identifier of UE as first indication information to be borne in the establishment request, wherein the PDU session identifier of the second PDU session is the same as the PDU session identifier of the first PDU session;

the policy control function entity 1001 is further configured to store a first correspondence between a UE identity of the UE and a PDU session identity of the first PDU session, and an AF session identity of the first AF session.

Optionally, the second PDU session setup request includes a PDU session identifier of the first PDU session;

the second session management functional entity 1003 is specifically configured to:

determining that the second PDU session establishment request is a reestablishment request, and taking the first PDU session identifier and the UE identifier as first indication information to be borne in the establishment request;

the association information of the first AF session may include: the UE identifier of the UE and the PDU session identifier of the first PDU session are in corresponding relation with the AF session identifier of the first AF session;

the policy control function entity 1001 is also configured to store the correspondence.

Optionally, the second PDU session establishment request includes a first inter-network internet protocol IP address corresponding to the first PDU session; SMF2 is specifically used for:

determining that the second PDU session establishment request is a reestablishment request, and taking the first PDU session identifier, the first IP address and a DNN identifier corresponding to the second PDU session establishment request as first indication information to be loaded in the establishment request;

the association information of the first AF session may include: a first corresponding relation between a first IP address, a DNN identifier corresponding to the first PDU session and an AF session identifier of the first AF session;

Optionally, the second session management function entity is further configured to allocate the first IP address for the second PDU session.

In the embodiment corresponding to fig. 10, the flows executed by the policy control function entity 1001, the first session management function entity 1002, and the second session management function entity 1003 in the session processing system are similar to the method flows described in the embodiments shown in fig. 5 to fig. 7, and are not described again here.

In addition, the specific functional module division in the policy control functional entity 1001 is similar to the functional module division described in the foregoing fig. 9, and is not described herein again.

Referring to fig. 11, an embodiment of the session management function entity in the present application may include one or more central processing units 1101, a memory 1102, an input/output interface 1103, a wired or wireless network interface 1104, and a power source 1105.

Memory 1102 may be transient storage or persistent storage. Still further, the central processor 1101 may be configured to communicate with the memory 1102 to perform a series of instruction operations in the memory 1102 on the session management function.

In this embodiment, the central processing unit 1101 may perform the operations performed by the session management function entity in the embodiments shown in fig. 3 and fig. 4, which are not described herein again.

In this embodiment, the specific functional module division in the central processing unit 1101 may be similar to the functional module division manner of the sending module, the receiving module, the determining module, the first allocating module, the second allocating module, and the like described in the foregoing fig. 8, and details are not repeated here.

It should be understood that the above-mentioned structural diagram shown in fig. 11 may also be a structural diagram of a policy control function entity, in which case, the central processor 1101 communicates with the memory 1102, and a series of operations in the memory 1101 are executed on the policy control function entity.

In this embodiment of the application, the central processing unit 1101 may also perform the operations performed by the session management function entity in the embodiments shown in fig. 5 and fig. 7, which are not described herein again in detail.

In this embodiment of the application, the specific functional module division in the central processing unit 1101 may also be similar to the functional module division manner of the modules described in fig. 9, such as the first receiving module, the releasing module, the second receiving module, and the determining module, and is not described herein again.

An embodiment of the present application further provides a computer storage medium, where the computer storage medium is used to store computer software instructions for the session management function entity and the policy control function entity, and includes a program for executing the program designed for the session management function entity and the policy control function entity.

The session management function may be as described in the foregoing fig. 3 and fig. 4.

The policy control function may be as described in the foregoing fig. 5 to 7.

An embodiment of the present application further provides a computer program product, where the computer program product includes computer software instructions, and the computer software instructions may be loaded by a processor to implement the flow in the session processing method in any one of fig. 3 to 7.

It is clear to those skilled in the art that, for convenience and brevity of description, the specific working processes of the above-described systems, apparatuses and units may refer to the corresponding processes in the foregoing method embodiments, and are not described herein again.

In the several embodiments provided in the present application, it should be understood that the disclosed system, apparatus and method may be implemented in other manners. For example, the above-described apparatus embodiments are merely illustrative, and for example, the division of the units is only one logical division, and other divisions may be realized in practice, for example, a plurality of units or components may be combined or integrated into another system, or some features may be omitted, or not executed. In addition, the shown or discussed mutual coupling or direct coupling or communication connection may be an indirect coupling or communication connection through some interfaces, devices or units, and may be in an electrical, mechanical or other form.

The units described as separate parts may or may not be physically separate, and parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of the embodiment.

In addition, functional units in the embodiments of the present application may be integrated into one processing unit, or each unit may exist alone physically, or two or more units are integrated into one unit. The integrated unit can be realized in a form of hardware, and can also be realized in a form of a software functional unit.

The integrated unit, if implemented in the form of a software functional unit and sold or used as a stand-alone product, may be stored in a computer readable storage medium. Based on such understanding, the technical solution of the present application may be substantially implemented or contributed to by the prior art, or all or part of the technical solution may be embodied in a software product, which is stored in a storage medium and includes instructions for causing a computer device (which may be a personal computer, a server, or a network device) to execute all or part of the steps of the method according to the embodiments of the present application. 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.

The above embodiments are only used for illustrating the technical solutions of the present application, and not for limiting the same; although the present application has been described in detail with reference to the foregoing embodiments, it should be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions in the embodiments of the present application.

Claims

1. A session processing method, comprising:

a session management function entity (SMF) sends a PDU session reestablishment instruction to User Equipment (UE);

the SMF receives a setup request of a second Packet Data Unit (PDU) session from the UE, wherein the setup request comprises first indication information;

the SMF determines a first policy control session according to the first indication information and the association information of the first policy control session, and determines a policy control session corresponding to the second PDU session as the first policy control session; the first policy control session is a policy control session corresponding to a first PDU session, and the first PDU session is a PDU session released by the UE before the second PDU session is established.

2. The method of claim 1, wherein the association information for the first policy control session comprises: a first correspondence between a first PDU session and the first policy control session.

3. The method of claim 2, wherein the first correspondence comprises: the UE identification of the UE and the first PDU session identification of the first PDU session are in corresponding relation with the strategy control session identification of the first strategy control session;

the first indication information comprises the UE identification and the first PDU session identification.

4. The method of claim 2, wherein the first correspondence comprises: the corresponding relation between a first inter-network Internet Protocol (IP) address corresponding to a first Protocol Data Unit (PDU) session, a Data Network Name (DNN) identifier corresponding to the first PDU session and a policy control session identifier of a first policy control session;

the first indication information comprises the first IP address and the DNN identification.

5. The method of claim 2, wherein the first correspondence comprises: a corresponding relation between a UE identifier of the UE and a first PDU session identifier of a first PDU session, a first IP address corresponding to the first PDU session and a DNN identifier corresponding to the first PDU session;

the first indication information comprises the UE identification and the first PDU session identification;

the SMF determines a first policy control session according to the first indication information and the association information between the first PDU session and the first policy control session, and the SMF comprises the following steps:

and the SMF determines the strategy control session corresponding to the first IP address and the DNN identification corresponding to the UE identification and the first PDU session identification as the first strategy control session according to the corresponding relation.

6. The method of claim 1, wherein the association information comprises: a first IP address corresponding to a first PDU session and a DNN identifier corresponding to the first PDU session;

the first indication information comprises the first IP address and the DNN identification;

and the SMF determines the policy control session corresponding to the first IP address and the DNN identifier as the first policy control session according to the association information.

7. The method of claim 1, wherein the association information comprises: the UE identification of the UE and the DNN identification corresponding to the first PDU session are in corresponding relation with the first IP address corresponding to the first PDU session;

the first indication information comprises the UE identity and the DNN identity;

and the SMF determines the strategy control session corresponding to the first IP address and the DNN identifier corresponding to the UE identifier and the DNN identifier as the first strategy control session according to the corresponding relation.

8. The method of any of claims 1-7, wherein the SMF sends a PDU session re-establishment indication to a User Equipment (UE) before the SMF sends the PDU session re-establishment indication to the UE:

and when a preset PDU session release condition is met, the SMF stores the association information of the first policy control session.

9. The method of claim 8, wherein the preset PDU session release condition comprises: the location of the UE changes, or a failure occurs in the user plane termination function entity TUPF corresponding to the first PDU session.

10. The method of any of claims 1-7, wherein the SMF receiving the establishment request for the second PDU session from the UE comprises:

and the SMF allocates a first IP address corresponding to the first PDU session for the second PDU session.

11. The method of any of claims 1-7, wherein the SMF receiving the establishment request for the second PDU session from the UE comprises:

the SMF allocates a second IP address for the second PDU session, and the second IP address is different from a first IP address corresponding to the first PDU session;

and the SMF reports an IP address change instruction to a policy control function entity (PCF) corresponding to the first policy control session, wherein the IP address change instruction is used for indicating the PCF to change an IP address for the UE to perform data transmission.

12. A session processing method, comprising:

a policy control function entity PCF receives a release instruction of a first policy control session sent by a first session management function entity SMF1, wherein the first policy control session corresponds to a first application function entity AF session; the first AF session is an AF session corresponding to a first Packet Data Unit (PDU) session, and the first PDU session is a PDU session released by User Equipment (UE);

the PCF releases the first policy control session according to the release instruction;

the PCF receives a request for establishing a second policy control session sent by a second session management function entity SMF2, wherein the request for establishing comprises first indication information;

and the PCF determines the first AF session according to the first indication information and the correlation information of the first AF session, and determines the AF session corresponding to the second strategy control session as the first AF session.

13. The method of claim 12, wherein the release order comprises second indication information, and wherein the second indication information is used to indicate that the SMF1 cannot continue to provide service to the UE corresponding to the first policy control session.

14. The method of claim 13, wherein the second indication information comprises a first PDU session identification for the first PDU session.

15. The method according to any one of claims 12 to 14, wherein the association information comprises: a corresponding relationship between the UE identifier corresponding to the first PDU session and the first PDU session identifier of the first PDU session, and the AF session identifier of the first AF session;

the first indication information includes: the UE identification and the first PDU session identification.

16. The method according to claim 12 or 13, wherein the association information comprises: a corresponding relation between a first inter-network Internet Protocol (IP) address corresponding to the first PDU session, a Data Network Name (DNN) identifier corresponding to the first PDU session and an AF session identifier of the first AF session;

the first indication information includes: the DNN identification and the first IP address.

17. A session management function, SMF, comprising:

a sending module, configured to send a PDU session reestablishment indication to a user equipment UE;

a receiving module, configured to receive a setup request of a second packet data unit, PDU, session from the UE, where the setup request includes first indication information;

a determining module, configured to determine a first policy control session according to the first indication information and association information of the first policy control session received by the receiving module, and determine a policy control session corresponding to the second PDU session as the first policy control session; the first policy control session is a policy control session corresponding to a first PDU session, and the first PDU session is a PDU session released by the UE before the second PDU session is established.

18. The SMF of claim 17, wherein the association information comprises: a first correspondence between a first PDU session and the first policy control session.

19. The SMF of claim 18, wherein said first correspondence comprises: a corresponding relation between a UE identifier of the UE and a first PDU session identifier of a first PDU session, a first IP address corresponding to the first PDU session and a DNN identifier corresponding to the first PDU session;

the determining module is configured to determine a first policy control session according to the first indication information and the association information of the first policy control session received by the receiving module, and specifically includes: and determining the strategy control session corresponding to the first IP address and the DNN corresponding to the UE identifier and the first PDU session identifier as the first strategy control session according to the corresponding relation.

20. The SMF of claim 17, wherein the association information comprises: a first IP address corresponding to a first PDU session and a DNN identifier corresponding to the first PDU session;

the determining module is configured to determine a first policy control session according to the first indication information and the association information of the first policy control session received by the receiving module, and specifically includes: and determining the policy control session corresponding to the first IP address and the DNN identifier as the first policy control session according to the associated information.

21. The SMF of claim 17, wherein the association information comprises: the UE identification of the UE and the DNN identification corresponding to the first PDU session are in corresponding relation with the first IP address corresponding to the first PDU session;

the determining module is configured to determine a first policy control session according to the first indication information and the association information of the first policy control session received by the receiving module, and specifically includes: and determining the first IP address corresponding to the UE identifier and the DNN identifier and the policy control session corresponding to the DNN identifier as the first policy control session according to the corresponding relation.

22. The SMF according to any of claims 17-21, wherein said SMF further comprises:

and the storage module is used for storing the associated information of the first strategy control session when the preset PDU session release condition is determined to be met.

23. The SMF according to any of claims 17-21, wherein said SMF further comprises:

and the first distribution module is used for distributing a first IP address corresponding to the first PDU session for the second PDU session.

24. The SMF according to any of claims 17-21, wherein said SMF further comprises:

a second allocating module, configured to allocate a second IP address to the second PDU session, where the second IP address is different from the first IP address corresponding to the first PDU session;

the sending module is further configured to: and reporting an IP address change instruction to a policy control function entity (PCF) corresponding to the first policy control session, wherein the IP address change instruction is used for indicating the PCF to change an IP address for the UE to perform data transmission.

25. A policy control function, PCF, comprising:

a first receiving module, configured to receive a release instruction of a first policy control session sent by a first session management function entity SMF1, where the first policy control session corresponds to a first application function entity AF session; the first AF session is an AF session corresponding to a first Packet Data Unit (PDU) session, and the first PDU session is a PDU session released by User Equipment (UE);

a release module, configured to release the first policy control session according to the release instruction received by the first receiving module;

a second receiving module, configured to receive a request for establishing a second policy control session sent by a second session management function entity SMF2, where the request for establishing includes first indication information;

a determining module, configured to determine the first AF session according to the first indication information and the association information of the first AF session received by the second receiving module, and determine that an AF session corresponding to the second policy control session is the first AF session.

26. A session processing system, comprising: a policy control function entity PCF, a first session management function entity SMF1 and a second session management function entity SMF 2;

the SMF1 is used for: sending a PDU session reestablishment instruction to UE, and sending a release instruction of a first policy control session to the PCF, wherein the first policy control session corresponds to a first application function entity (AF) session; the first AF session is an AF session corresponding to a first Packet Data Unit (PDU) session, and the first PDU session is a PDU session released by User Equipment (UE);

the SMF2 is used for: receiving a second PDU session establishment request from the UE, and sending an establishment request of a second policy control session to the PCF, wherein the establishment request comprises first indication information;

the PCF is used for: and releasing the first policy control session according to the release instruction, determining the first AF session according to the first indication information and the association information of the first AF session, and determining the AF session corresponding to the second policy control session as the first AF session.

27. The system of claim 26,

the SMF2 is specifically configured to:

taking the PDU session identifier of the second PDU session and the UE identifier of the UE as first indication information to be borne in the establishment request, wherein the PDU session identifier of the second PDU session is the same as the PDU session identifier of the first PDU session;

the associated information includes: and the UE identification of the UE, the PDU session identification of the first PDU session and the AF session identification of the first AF session.

28. The system of claim 26,

the second PDU session establishment request comprises a PDU session identifier of the first PDU session;

the SMF2 is specifically configured to:

determining that the second PDU session establishment request is a reestablishment request, and using the first PDU session identifier and the UE identifier as first indication information to be borne in the establishment request;

29. The system of claim 26 wherein the second PDU session setup request includes a first inter-network internet protocol, IP, address corresponding to the first PDU session;

the SMF2 is specifically configured to:

determining that the second PDU session establishment request is a reestablishment request, and using the first PDU session identifier, the first IP address and a DNN identifier corresponding to the second PDU session establishment request as first indication information to be loaded in the establishment request;

the associated information includes: and the first IP address, the DNN identifier corresponding to the first PDU session and the AF session identifier of the first AF session are in corresponding relation.

30. The system of claim 28 wherein the SMF2 is further configured to assign a first IP address to the second PDU session, the first IP address corresponding to the first PDU session.