CN113438664A

CN113438664A - Session path optimization method and device

Info

Publication number: CN113438664A
Application number: CN202110614517.XA
Authority: CN
Inventors: 马泽芳; 任驰; 马瑞涛; 李晨仪
Original assignee: China United Network Communications Group Co Ltd
Current assignee: China United Network Communications Group Co Ltd
Priority date: 2021-06-02
Filing date: 2021-06-02
Publication date: 2021-09-24
Anticipated expiration: 2041-06-02
Also published as: CN113438664B

Abstract

The invention provides a session path optimization method and device, relates to the field of communication, and solves the contradiction problem of session continuity and path roundabout existing in a 5G network architecture by optimizing a session path when a session is in an idle state. The method comprises the following steps: the anchor point conversation management network element A-SMF determines that a conversation path of a first conversation comprises an intermediate conversation management network element I-SMF, and the first conversation is in an activated state; under the condition that a preset condition is met, the A-SMF sends a command message to the terminal equipment; the command message is used for indicating the terminal equipment to release the first session and establishing a second session to a data network connected with the first session; the preset conditions include: the A-SMF determines that the I-SMF is in a different region than the A-SMF, and the first session transitions from an active state to an idle state.

Description

Session path optimization method and device

Technical Field

The present application relates to the field of communications, and in particular, to a method and an apparatus for session path optimization.

Background

In a fifth generation (5th generation, 5G) network, in order to meet service continuity requirements of different applications, three different session and service continuity modes (SSC modes) are designed for a Protocol Data Unit (PDU) session. The SSC mode1 can provide session continuity, and is mainly applied to typical applications such as IP Multimedia Subsystem (IMS) voice which have high requirements on continuity. A User Plane Function (UPF) serving as a user plane anchor point remains unchanged in the whole life cycle of a session, and if an anchor point UPF (anchor UPF) in the session of a terminal device cannot be covered on the terminal device due to the movement of the terminal device, an intermediate session management function (I-SMF) is introduced, and the intermediate SMF may select an intermediate UPF, so that the terminal device may be connected to the anchor point UPF through the intermediate UPF.

However, although this method ensures the continuity of the session and the service, it cannot guarantee the optimal bearer path of the service, that is, when the terminal device moves across the area, the path detour is caused by inserting the I-SMF and the I-UPF in the session path. On one hand, the path detour increases the time delay of the session, and on the other hand, when the terminal device moves across areas, especially across provinces (across large areas), the function or service based on the position of the terminal device cannot be realized.

Disclosure of Invention

The application provides a session path optimization method and device, which solve the contradiction problem of session continuity and path detour existing in a 5G network architecture by optimizing a session path when a session is converted from an active state to an idle state.

In order to achieve the purpose, the technical scheme is as follows:

in a first aspect, the present application provides a session path optimization method, which may include:

the anchor point conversation management network element A-SMF determines that a conversation path of a first conversation comprises an intermediate conversation management network element I-SMF, and the first conversation is in an activated state; under the condition that a preset condition is met, the A-SMF sends a command message to the terminal equipment; the command message is used for indicating the terminal equipment to release the first session and establishing a second session to a data network connected with the first session; the preset conditions include: the A-SMF determines that the I-SMF is in a different region than the A-SMF, and the first session transitions from an active state to an idle state.

In a second aspect, the present application provides a session path optimization method, which may include: an anchor point conversation management network element A-SMF receives a request message of an intermediate conversation management network element I-SMF; the request message is used for requesting to insert the I-SMF in a session path of a first session; if the A-SMF determines that the I-SMF is in a different area than the A-SMF and the first session is active, the A-SMF accepts and completes inserting the I-SMF in the session path of the first session; under the condition that a preset condition is met, the A-SMF sends a command message to the terminal equipment; the command message is used for indicating the terminal equipment to release the first session and establishing a second session to a data network connected with the first session; the preset conditions include: the first session is transitioned from an active state to an idle state.

In a third aspect, the present application provides a session path optimization device, including: the device comprises a processing module and a sending module. The processing module is configured to determine that a session path of a first session includes an intermediate session management network element I-SMF, and the first session is in an active state; the processing module is further used for determining whether a preset condition is met; wherein the preset conditions include: the A-SMF determines that the area where the I-SMF is located is different from the area where the A-SMF is located, and the first session is converted from an active state to an idle state; the sending module is used for sending a command message to the terminal equipment under the condition that the preset condition is met; the command message is used for instructing the terminal equipment to release the first session and establish a second session to a data network connected with the first session.

In a fourth aspect, the present application provides a session path optimization apparatus, including: the device comprises a receiving module, a processing module and a sending module. The receiving module is used for receiving a request message of an intermediate session management network element I-SMF; the request message is used for requesting to insert the I-SMF in a session path of a first session; a processing module, configured to accept and complete inserting the I-SMF in a session path of the first session if the a-SMF determines that the I-SMF is located in a different area than the a-SMF and the first session is in an active state; the processing module is further used for determining whether a preset condition is met; wherein the preset conditions include: the first session is converted from an active state to an idle state; the sending module is used for sending a command message to the terminal equipment under the condition that the preset condition is met; the command message is used for instructing the terminal equipment to release the first session and establish a second session to a data network connected with the first session.

In a fifth aspect, the present application provides a session path optimization device, including: a processor, a communication interface, a bus, and a memory. Wherein the memory is configured to store one or more programs, and the one or more programs include computer executable instructions, and when the session path optimization apparatus runs, the processor executes the computer executable instructions stored in the memory, so as to cause the session path optimization apparatus to execute the session path optimization method according to any one of the first aspect, the second aspect, and various optional implementations thereof.

In a sixth aspect, the present application provides a computer-readable storage medium, in which computer-executable instructions are stored, and when the computer executes the computer-executable instructions, the computer executes the session path optimization method according to any one of the first aspect, the second aspect, and various optional implementation manners of the first aspect and the second aspect.

In a seventh aspect, the present application provides a computer program product comprising instructions, which when run on a computer, cause the computer to perform the session path optimization method of any one of the first aspect, the second aspect and various alternative implementations thereof.

According to the session path optimization method and device provided by the application, the A-SMF determines that a session path of a first session comprises an I-SMF, and the first session is in an activated state; under the condition that a preset condition is met, the A-SMF sends a command message to the terminal equipment; the command message is used for indicating the terminal equipment to release the first session and establishing a second session to a data network connected with the first session; the preset conditions include: the A-SMF determines that the I-SMF is in a different region than the A-SMF, and the first session transitions from an active state to an idle state. Compared with the prior art, the SSC mode1 is adopted to keep the user plane anchor point UPF unchanged, and the insertion of the I-SMF and the I-UPF in the session path causes the session path to be circuitous. According to the session path optimization method provided by the application, by enhancing the function of the A-SMF network element, the A-SMF network element initiates session release when determining that the area where the I-SMF is located is different from the area where the A-SMF is located and the session is converted from the active state to the idle state, and instructs the terminal equipment to establish a new PDU session to access the same data network, during session reestablishment, the A-SMF of a roaming place and the A-UPF of the roaming place which are more optimized in routing are selected, and the I-SMF and the I-UPF do not need to be inserted, so that the path of the PDU session is optimized, and the problem of path detour existing in the service adopting SSC mode1 in the operator strategy is solved under the condition that the session and service continuity are not affected.

Drawings

FIG. 1 is a schematic diagram of the R15 architecture of the 5G system;

FIG. 2 is a schematic diagram of the R16 architecture of the 5G system;

fig. 3 is a schematic diagram of a communication system according to an embodiment of the present invention;

fig. 4 is a first flowchart illustrating a session path optimization method according to an embodiment of the present application;

fig. 5 is a schematic diagram of a network element example identifier encoding method according to an embodiment of the present application;

fig. 6 is a flowchart illustrating a second session path optimization method according to an embodiment of the present application;

fig. 7 is a third flowchart illustrating a session path optimization method according to an embodiment of the present application;

fig. 8 is a fourth flowchart illustrating a session path optimization method according to an embodiment of the present application;

fig. 9 is a fifth flowchart illustrating a session path optimization method according to an embodiment of the present application;

fig. 10 is a sixth flowchart of a session path optimization method according to an embodiment of the present application;

fig. 11 is a first schematic structural diagram of a session path optimization apparatus according to an embodiment of the present invention;

fig. 12 is a schematic structural diagram of a session path optimization apparatus according to an embodiment of the present invention;

fig. 13 is a schematic structural diagram of a session path optimization apparatus according to an embodiment of the present invention.

Detailed Description

The following describes in detail a session path optimization method and apparatus provided by the embodiments of the present invention with reference to the accompanying drawings.

The term "and/or" herein is merely an association describing an associated object, meaning that three relationships may exist, e.g., a and/or B, may mean: a exists alone, A and B exist simultaneously, and B exists alone.

The terms "first" and "second" and the like in the description of the present invention and the drawings are used for distinguishing different objects or for distinguishing different processes for the same object, and are not used for describing a specific order of the objects.

Furthermore, the terms "comprising" and "having" and any variations thereof as referred to in the description of the invention are intended to cover non-exclusive inclusions. For example, a process, method, system, article, or apparatus that comprises a list of steps or elements is not limited to only those steps or elements but may alternatively include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.

It should be noted that, in the embodiments of the present invention, words such as "exemplary" or "for example" are used to indicate examples, illustrations or explanations. Any embodiment or design described as "exemplary" or "e.g.," an embodiment of the present invention is not necessarily to be construed as preferred or advantageous over other embodiments or designs. Rather, use of the word "exemplary" or "such as" is intended to present concepts related in a concrete fashion.

In the description of the present invention, the meaning of "a plurality" means two or more unless otherwise specified.

Before introducing the concepts of the present application, a number of terms of communication referred to in the present application will be explained.

One, session and service continuity mode

The SSC mode in a 5G system can meet the continuity requirements of different applications or services. Different SSC modes are supported in a 5G system, and the SSC modes mainly comprise the following SSC modes:

1) SSC mode 1: the PDU session in this mode can provide session continuity. In the moving process of the UE, regardless of the access technology type of the UE and the location of the UE, after the PDU session is established, the UPF serving as a PDU Session Anchor (PSA) remains unchanged.

2) SSC mode 2: the PDU session in this mode cannot guarantee service continuity for the UE. Based on the policy and other information of the operator, the network side may release the current PDU session and notify the UE to establish a new PDU session. In the newly established PDU session, the UPF as the PSA can reselect.

3) SSC mode 3: for the PDU session of SSC mode3, the network side allows a new PDU session to be established for the Data Network Name (DNN) of the PDU session, and after the new PDU session is established, the previously established PDU session may be released after a certain time. There are many situations where the network side allows conditions for setting up a new PDU session for the DNN of that PDU session, such as due to the mobility of the UE, or due to load balancing of the devices, etc.

It should be noted that, as the communication technology evolves, the name of the above SSC mode may change, and as long as the specific meaning of the SSC mode is the same as that of the above SSC mode in the present application, no matter how the name changes, the name will fall into the protection scope of the present application.

Quality of service (QoS) flow (QoS flow) and 5GQoS identity (5G QoS identity, 5QI)

The 5G adopts an in-band (in-band) QoS marking mechanism, a gateway or an application server (APP server) marks a corresponding QoS processing label for the data flow based on the QoS requirement of the service, and a network side performs data packet forwarding based on the QoS label. The QoS label can change in real time based on the requirement of the service data flow, and the service requirement can be met in real time. The SMF is responsible for QoS control, and when a PDU session is established, the SMF configures corresponding QoS parameters to the UPF, AN Access Network (AN), and the UE. The QoS configuration of each QoS flow will contain 5QI parameters for indexing a 5G QoS characteristic, with different bearer services corresponding to different 5QI values.

III, DNN

The 5G network transfers data sent and received between the terminal (UE) and the external network in the form of packets, usually called Packet Data Units (PDUs), and the path established between the terminal and the external network is called a PDU session. And DNN is used in PDU sessions to identify different destination networks outside these 5G networks, e.g. a DNN value of "IMS" indicates that this PDU session is established for IMS services.

The technical solution of the embodiment of the present application may be applied to various communication systems, for example, a 4th generation (4G) mobile communication system, such as a Long Term Evolution (LTE) system, a 5G mobile communication system, such as a New Radio (NR) system, and a future communication system, such as a 6th generation (6G) mobile communication system.

For the convenience of understanding the embodiments of the present application, first, the communication system shown in fig. 1 to 3 is taken as an example, and the communication system applied to the embodiments of the present application is explained in detail. It should be noted that the solution in the embodiment of the present application may also be applied to other mobile communication systems, and the corresponding names may also be replaced with names of corresponding functions in other mobile communication systems.

For example, fig. 1 is a schematic diagram of an R15 architecture of a 5G system. As shown in fig. 1, the 5G system may include two parts, AN access network AN and a Core Network (CN). The AN is mainly used to implement functions related to radio access, and may include Radio Access Network (RAN) equipment, where the core network mainly includes the following network elements: an access and mobility management (AMF) network element, an SMF network element, an UPF network element, a Policy Control Function (PCF) network element, a Unified Data Management (UDM) network element, and an Application Function (AF) network element. The following is a brief description of some network elements included in the architecture and the functions of each network element.

A terminal device, also called a User Equipment (UE), a terminal (terminal), a Mobile Station (MS), a Mobile Terminal (MT), etc., is a device that provides voice/data connectivity to a user, for example, a handheld device with a wireless connection function, a vehicle-mounted device, etc. Currently, some examples of terminal devices are: a mobile phone (mobile phone), a tablet computer, a notebook computer, a palm top computer, a Mobile Internet Device (MID), a wearable device, a Virtual Reality (VR) device, an Augmented Reality (AR) device, a wireless terminal in industrial control (industrial control), a wireless terminal in self-driving (self-driving), a wireless terminal in remote surgery (remote medical supply), a wireless terminal in smart grid (smart grid), a wireless terminal in transportation safety (transportation safety), a wireless terminal in city (smart city), a wireless terminal in smart home (smart home), and the like.

An access network device is a Radio Access Network (RAN) node that accesses a terminal device to a wireless network. Currently, some examples of RAN nodes are: next generation base station (gNB), Transmission Reception Point (TRP), evolved Node B (eNB), Radio Network Controller (RNC), Node B (NB), Base Station Controller (BSC), Base Transceiver Station (BTS), home base station (e.g., home evolved Node B, or home Node B, HNB), Base Band Unit (BBU), or wireless fidelity (WiFi) Access Point (AP), etc.

AMF network element: is mainly responsible for the signaling processing parts, such as: access control, mobility management, registration and de-registration, etc. When the AMF network element provides service for the session in the UE, a storage resource of a control plane is provided for the session, so as to store the session identifier, the SMF network element identifier associated with the session identifier, and the like.

SMF network element: the session management module is mainly responsible for session management in a wireless network, such as session establishment, modification, release and QoS control, and specific functions may include user plane network element selection, user plane network element redirection, Internet Protocol (IP) address allocation between networks, and the like.

The PCF network element mainly supports providing a uniform strategy framework to control network behaviors, provides strategy rules to a control layer network function, and is responsible for acquiring user subscription information related to strategies.

UPF network element: the method is mainly responsible for forwarding and receiving user data of the terminal equipment. User data can be received from a Data Network (DN) and transmitted to a terminal device through an access network device; the UPF network element may also receive user data from the terminal device via the access network device and forward the user data to the data network. The transmission resource and scheduling function for providing service for the terminal equipment in the UPF network element are managed and controlled by the SMF network element.

And the UDM network element is mainly responsible for storing the structured data, and the stored content comprises subscription data, strategy data, externally-exposed structured data and application-related data.

AF network element: mainly supports the interaction with the 3GPP core network to provide services, such as influencing data routing decision, strategy control function or providing some services of a third party to the network side.

The DN may be an operator network providing data transmission service for the user, such as IMS, or an external network connected to the operator network, such as an internet (internet), a network deployed by a content provider (content provider), or the like.

Wherein, an interface between the UE and the AMF network element is referred to as an N1 interface, an interface between the AMF network element and the RAN device is referred to as an N2 interface, an interface between the RAN device and the UPF network element may be referred to as an N3 interface, an interface between the SMF network element and the UPF network element is referred to as an N4 interface, an interface between the PCF network element and the AF network element is referred to as an N5 interface, an interface between the UPF network element and the DN is referred to as an N6 interface, an interface between the SMF network element and the PCF network element is referred to as an N7 interface, an interface between the AMF network element and the UDM network element is referred to as an N8 interface, an interface between different UPF network elements is referred to as an N367 interface, an interface between the UDM network element and the SMF network element is referred to as an N10 interface, an interface between the AMF network element and the SMF network element is referred to as an N11 interface, an interface between the AUSF network element and the AMF network element is referred to as an N12 interface, an interface between the AUSF network element and the udf 13 interface between the udf network element, an interface between the different amsf 13 network element is referred to as an N14 interface between the previous AMF network element.

As shown in fig. 2, is the R16 architecture of 5G. Compared with the R15 architecture shown in fig. 1, the main differences are that: the R16 architecture shown in fig. 2 supports multiple SMFs, i.e., supports plug-in SMFs. Thus, SMFs can be classified as anchor SMFs (A-SMFs) and intermediate SMFs (I-SMFs), where I-SMFs refer to intervening SMFs.

A-SMF, which is the SMF serving the PDU session, controls an anchor UPF (A-UPF) and may perform UE IP address assignment.

The I-SMF is mainly responsible for the management of I-UPF in the jurisdiction, including the selection of I-UPF, the load sharing among I-UPF, and the session management function (including the establishment of user plane tunnel, the configuration of I-UPF forwarding rule, etc.). The I-SMF may manage I-UPF that is not controlled by A-SMF and has an N3 interface.

The I-SMF may be selected to be inserted, switched or removed from the network as desired. For example, referring to fig. 2, as the UE moves from area 1 to area 2, the UE requests to establish a session or handover a session at a new location, and the a-UPF cannot provide service to the UE at the new location of the UE, i.e., the a-UPF cannot cover the new location of the UE, an I-SMF is inserted into the network, and then the I-SMF selects an I-UPF, which is inserted into the session path of the UE, so that the session of the UE is connected to the a-UPF managed by the a-SMF through the I-UPF, and the session is activated or handed over.

By introducing the I-SMF into the 5GC architecture, the user can still ensure the session continuity of the SSC mode1 service when moving across large areas or provinces, namely, the UPF serving as a PDU session anchor point when the session is established is ensured to be kept unchanged in the whole session process. This characteristic is generally used for services such as 5G NR voice, video over new radio (VoNR) and the like, which have relatively high requirements for continuity, and in fact, according to the operator policy of the current network, this characteristic is also applied to data network services.

As can be seen from fig. 2, for a service using SSC mode1, the UPF as the anchor point of the user plane remains unchanged throughout the lifetime of the session, and although the continuity of the session and the service is ensured, the bearer path of the service cannot be guaranteed to be optimal, that is, there is a detour path. On the other hand, when the UE moves, especially moves from province (large area) to province (large area) B, the UE does not configure the wireless location information of province (large area) a in the 5G network and the IMS network of province B (large area), which may result in that the UE location-based function or service in the 5G voice or video service, such as complementing the area number of the called number according to the location information of the UE, accessing the nearby emergency call center according to the location of the user when the user dials the emergency call number, and the like, cannot be implemented.

For the technical problem, the currently adopted strategy is to disconnect the session connection with the original area and reconnect the session connection in a new area by means of the occasions of shutdown restart, flight mode switching, tunnel-passing signal interruption and the like encountered in the user trip process, or to intensively detect the terminal equipment with the problems at night in a time period with less user traffic, such as 22:00-02:00, and release and reestablish the session, thereby avoiding the technical problem. However, these methods are not reliable, and if the user does not encounter the above-mentioned occasion, the above-mentioned problems of path detour and function defect will exist all the time before the session release is performed, which seriously affects the normal use of the user.

Fig. 3 is a schematic structural diagram of a communication system to which the session path optimization method provided in the embodiment of the present application is applied. As shown in fig. 3, the communication system includes a terminal device, an access and mobility management network element, an intermediate session management network element, and an anchor session management network element. Optionally, the communication system further includes an access network device, an intermediate user plane network element, an anchor user plane network element, and/or a data network element.

The SSC mode1 is adopted for a first session established from the terminal device to the data network element through the access network device and the anchor point user plane network element, the anchor point session management network element is an SMF serving the first session, and the anchor point user plane network element managed by the anchor point session management network element is a user plane anchor point of the first session. The movement of the terminal equipment breaks away from the coverage range of the anchor user plane network element, the access and mobility management network element decides to insert the intermediate session management network element in the network, and then inserts the intermediate user plane network element managed by the intermediate session management network element into the user plane path of the first session.

In this embodiment of the present application, the functions of the access and mobility management network element shown in fig. 3 may be implemented by the AMF network element shown in fig. 2, the functions of the anchor session management network element shown in fig. 3 may be implemented by the a-SMF network element shown in fig. 2, the functions of the anchor user plane network element shown in fig. 3 may be implemented by the a-UPF network element shown in fig. 2, the functions of the intermediate session management network element shown in fig. 3 may be implemented by the I-SMF network element shown in fig. 2, and the functions of the intermediate user plane network element shown in fig. 3 may be implemented by the I-UPF network element shown in fig. 2. The functions of the terminal device shown in fig. 3 may be implemented by the UE shown in fig. 2. The functionality of the access network equipment shown in fig. 3 may be implemented by the RAN shown in fig. 2. The functions of the data network elements shown in figure 3 may be implemented by the DNs shown in figure 2.

The embodiment of the present application provides a session path optimization method, which may be applied to the communication system shown in any one of fig. 1 to 3. The following is an illustration of the communication system shown in fig. 3. As shown in fig. 4, the method includes S101-S102:

s101, the A-SMF determines that a session path of the first session comprises the I-SMF and the first session is in an activated state.

Illustratively, the first session is a PDU session established between the UE and the external data network, using SSC mode 1. The A-SMF provides services such as session management and the like for the PDU session, so that the session context of the PDU session is stored, and the A-SMF determines that the I-SMF is inserted into a signaling path of the PDU session according to the session context of the PDU session. At this time, the end-to-end user plane path of the session includes an N9 tunnel between I-UPF and A-UPF, an N3 tunnel between I-UPF and RAN, and a radio connection between RAN and UE, uplink data is transmitted by the UE to the data network via RAN, I-UPF, A-UPF, and downlink data is transmitted by the data network to the UE via A-UPF, I-UPF, and RAN.

In an implementation manner, if the first session is an IP multimedia subsystem IMS service session, the activation state of the first session refers to: the first session has a 5G quality of service identity 5QI ═ 1 data flow.

Illustratively, if the a-SMF determines that the DNN field of the PDU session is "ims", the state of the PDU session is determined by detecting the state of a QoS flow of which 5QI is 1 in the session. For IMS voice or video call services, a 5QI ═ 5 QoS flow carries the most basic IMS signaling connection. On the basis, the voice call also has a QoS flow of 5QI ═ 1, and the voice call carries call voice connection; the video call also has a QoS stream of 5QI ═ 1 and a QoS stream of 5QI ═ 2, which carry the call voice connection and the call video connection, respectively. Therefore, when the DNN field of the session is "IMS", if it is determined that a QoS flow of 5QI ═ 1 exists in the session, that is, the IMS voice connection is included, it is determined that the first session is in an active state.

In another implementation manner, if the first session is a data service session, the activation state of the first session refers to: the first session exists with a data flow carrying data transport.

For example, if the a-SMF determines that the DNN field of the PDU session is "xxnet" or "xxmap", the state of the PDU session is determined by detecting the state of the QoS flow carrying the user plane data transmission in the session. For data services, the DNNs of different operators may be different, for example, the DNNs of data services defined by china unicom are 3gnet and 3gwap, and the DNNs of data services defined by china mobile are cmnet and cmwap. In general, only one QoS flow for carrying data traffic exists in a data traffic session, and only a few high-security services will establish a plurality of QoS flows higher than the general QoS. Therefore, in the case that the DNN field of the session is xxnet "or" xxmap ", if it is determined that the PDU session has a QoS flow for carrying data transmission, it is determined that the session is in an active state.

S102, the A-SMF sends a command message to the terminal equipment under the condition that a preset condition is met.

The command message is used for instructing the terminal device to release the first session and establish a second session to a data network connected with the first session, and the preset conditions include: the A-SMF determines that the area in which the I-SMF is located is different from the area in which the A-SMF is located, and the first session transitions from an active state to an idle state.

In one implementation, the A-SMF determines that the region in which the I-SMF is located is different from the region in which the A-SMF is located by comparing the I-SMF with its own identity. When the area where the I-SMF is located is different from the area where the I-SMF is located, the A-SMF determines that a path detour exists in a session path of the first session after the A-SMF inserts the intermediate network elements (I-SMF and I-UPF), and the A-SMF accordingly determines that the session needs to be subjected to path optimization.

Illustratively, the identifier of the I-SMF and the identifier of the a-SMF are network function identifier (network function identifier ID) of the I-SMF and the a-SMF, which are unique identifiers of the NF, are uniformly planned by the operator, the identifier of the network element instance is 16 bytes, and the identifier adopts a Universal Unique Identifier (UUID) format, that is, the identifier of the network element instance is a UUID format

UUID＝time-low"-"time-mid"-"

time-high-and-version"-"

clock-seq-and-reserved

clock-seq-low"-"node

The node part is 6 bytes, and the coding rule shown in fig. 5 is adopted, the first byte NF type identifies the network element type (e.g., session management network element), the second byte large area information identifies the large area (e.g., central china area) where the network element is located, the third byte province information identifies the province (e.g., south of the river) served by the network element, and the last three bytes are the instance number (instance sequence number) of the network element. The example sequence number includes a field indicating the intra-province fragment area information to which the network element service area belongs, for example, 2 bits (which can be expanded according to needs, and 2 bits are enough according to the current situation) are adopted for city and land coding, when the code is 00, the city and land coding is indicated as covering the whole province, 01 indicates a province meeting, and 10 indicates a second central city in the province.

In one implementation, the region in which I-SMF is located is different from the region in which A-SMF is located, including one of: A-SMF and I-SMF belong to different large regions; or A-SMF and I-SMF belong to the same large region but belong to different provinces; alternatively, A-SMF and I-SMF belong to the same province but to different province regions. In other words, the area where the I-SMF is located is different from the area where the a-SMF is located, which indicates that the UE is currently in a roaming state, and the area where the I-SMF is located is the roaming place of the UE.

Illustratively, the A-SMF compares the I-SMF with own large area information, if the large area information is different, it is determined that the UE is roaming across large areas, the areas where the I-SMF and the A-SMF are located belong to different large areas, and the session needs to be subjected to path optimization. And if the large area information of the I-SMF and the A-SMF is the same, the A-SMF continuously compares the I-SMF with own province information. If the province information is different, the UE is determined to be roaming across provinces, the areas where the I-SMF and the A-SMF are located belong to the same large area but do not belong to the same province, and path optimization is needed in the session. If the province information of I-SMF and A-SMF is the same, A-SMF continues to compare I-SMF with its own instance label. If the fields indicating the intra-province fragment area information in the example labels are different, it is determined that the UE moves across the intra-province fragment areas, the service areas of the I-SMF and the A-SMF belong to the same province and do not belong to the same intra-province area, and the session needs to be subjected to path optimization.

And the A-SMF checks the session path of the PDU session after determining that the intermediate network element I-SMF is inserted into the session path of the PDU session. Specifically, whether the I-SMF and the A-SMF requesting to be inserted into the session signaling path belong to the same large area, or belong to the same large area and do not belong to the same province, or belong to the same province and do not belong to the same intra-province area is determined by comparing the information related to the service area in the I-SMF and the network element instance identifier of the I-SMF, so that whether the PDU session needs to be subjected to path optimization can be determined simply and quickly.

In order to avoid causing ongoing service interruption and affecting normal use of the user, the preset condition further includes that the first session is converted from an active state to an idle state. Illustratively, after the A-SMF determines that the area where the I-SMF is located is different from the area where the A-SMF is located, event monitoring for the first session to be converted from the active state to the idle state is started, and once the first session is converted from the active state to the idle state, conditions for session path optimization are provided.

In one implementation, if the first session is an IP multimedia subsystem IMS service session, the transition of the first session from the active state to the idle state means: the release of the 5QI ═ 1 data stream for the first session is complete.

Illustratively, if the a-SMF determines that the DNN field of the PDU session is "ims", the state of the PDU session is determined by detecting the state of a QoS flow of which 5QI is 1 in the session. After the user call is ended, the release of the QoS flow with 5QI ═ 1 is included regardless of the voice call or the video call, so that when the DNN field of the PDU session is "ims", if the release event of the QoS flow with 5QI ═ 1 is detected, it is determined that the first session is switched from the active state to the idle state.

In another implementation manner, if the first session is a data service session, the transition of the first session from the active state to the idle state refers to: the data flow release for the bearer data transfer of the first session is complete.

For example, if the a-SMF determines that the DNN field of the PDU session is "xxnet" or "xxmap", the state of the PDU session is determined by detecting the state of the QoS flow carrying the user plane data transmission in the session. And if a QoS flow release event for bearing data transmission is detected, determining that the first session is converted from an active state to an idle state.

On the premise of determining that the PDU session is in an idle state, the session release can be started, otherwise, the ongoing service is interrupted, and the normal use of the user is influenced.

It should be noted that, in step S102, the timing for determining whether the two preset conditions are met by the a-SMF may be the same or different, and the present application is not limited herein.

And in the case that the area where the I-SMF is positioned is different from the area where the A-SMF is positioned and the first session is converted from the active state to the idle state, the A-SMF starts a session release flow. Further exemplarily, the command message is a session release command message (PDU session release command) in the a-SMF triggered PDU session release procedure, and since the PDU session release is initiated by the a-SMF trigger, the a-SMF creates an N1 session management (N1 SM) signaling containing the PDU session release command message (PDU session release command), and sends the session release command message to the UE via the I-SMF and the AMF. The session release command message includes an identifier (PDU session ID) of the first session, which is used to instruct the terminal device to release the PDU session corresponding to the session identifier, and an error cause value (cause), which is used to instruct the terminal device to establish a new PDU session, that is, to reestablish the new PDU session to the same DNN.

And the terminal equipment receives the session release command message, releases the old PDU session with the path detour, and rebuilds a new PDU session (second session) by using the same session identifier, session type, SSC mode and DNN, and selects the A-SMF of the roaming place and the A-UPF of the roaming place with more optimized routing without inserting I-SMF and I-UPF in the process of rebuilding the second session, thereby avoiding the path detour and optimizing the session path.

According to the session path optimization method provided by the application, the A-SMF determines that a session path of a first session comprises the I-SMF, and the first session is in an activated state; and under the condition that preset conditions are met, the A-SMF sends a command message to the terminal equipment, wherein the command message is used for indicating the terminal equipment to release the first session and establish a second session to a data network connected with the first session, and the preset conditions comprise: the A-SMF determines that the area in which the I-SMF is located is different from the area in which the A-SMF is located, and the first session transitions from an active state to an idle state. Compared with the prior art, the SSC mode1 is adopted to keep the user plane anchor point UPF unchanged, and the insertion of the I-SMF and the I-UPF in the session path causes the session path to be circuitous. According to the session path optimization method provided by the application, by enhancing the function of the A-SMF network element, the A-SMF network element initiates session release when determining that the area where the I-SMF is located is different from the area where the A-SMF is located and the session is converted from the active state to the idle state, and instructs the terminal equipment to establish a new PDU session to access the same data network, during session reestablishment, the A-SMF of a roaming place and the A-UPF of the roaming place which are more optimized in routing are selected, and the I-SMF and the I-UPF do not need to be inserted, so that the path of the PDU session is optimized, and the problem of path detour existing in the service adopting SSC mode1 in the operator strategy is solved under the condition that the session and service continuity are not affected.

In the case that the a-SMF network element determines that the area where the I-SMF is located is different from the area where the a-SMF is located, and the session is converted from the active state to the idle state, step S102 in the above embodiment selects to immediately start the session release procedure, and actually, in another implementation, to avoid missing a possible service, the session release procedure may also be selected to be started temporarily. Therefore, an embodiment of the present application further provides another session path optimization method, as shown in fig. 6, including S201-S202:

s201, the A-SMF determines that a session path of the first session comprises the I-SMF, and the first session is in an activated state.

The a-SMF determines that the session path of the first session includes the I-SMF, and the description that the first session is in the active state may specifically refer to the related description in step S101, which is not described herein again.

S202, under the condition that the preset condition is met, the A-SMF sends a command message to the terminal equipment.

The command message is used for instructing the terminal device to release the first session and establish a second session to a data network connected with the first session, and the preset conditions include: the A-SMF determines that the area where the I-SMF is located is different from the area where the A-SMF is located, the first session is converted from an active state to an idle state, and the time that the first session is in the idle state reaches a preset time length.

Exemplarily, as shown in fig. 6, step S202 specifically includes:

s202(a), A-SMF determines that the area where I-SMF is located is different from the area where A-SMF is located and the first session is converted from the active state to the idle state, and then starts a preset timer.

The description that the a-SMF determines that the area where the I-SMF is located is different from the area where the a-SMF is located and the first session is converted from the active state to the idle state may specifically refer to the related description in step S102, and details are not described here again.

Illustratively, the A-SMF determines that the area of the I-SMF in the current session path is different from the area of the A-SMF, thereby determining that path optimization is required, and the PDU session is converted from an active state to an idle state, and the PDU session is subjected to a condition of path optimization, but a session release flow is not immediately started, but a preset timer is started to limit the effective time of the session path including the intermediate network element.

Further exemplarily, the a-SMF starts a preset timer, selects to set a period of "buffering time" for the current session, and ensures the continuity of the session and the service during the period before the preset timer expires, thereby avoiding missing possible services.

It should be noted that the duration of the preset timer may be set according to actual conditions and operator policies, and the duration of the preset timer is not specifically limited in the present invention.

S202(b), the A-SMF determines that the first session is in an idle state before the preset timer is overtime, and the A-SMF sends a command message to the terminal equipment after the preset timer is overtime.

The command message is used for instructing the terminal equipment to release the first session and establish a second session to a data network connected with the first session.

For example, after starting the preset timer, the a-SMF continuously monitors the status of the PDU session, and corresponding to the above example, if the a-SMF determines that the PDU session is an IMS service session, the a-SMF determines the status of the PDU session by detecting the status of a QoS flow with 5QI ═ 1 in the PDU session. And if the A-SMF determines that the PDU session is a data service session, determining the state of the session by detecting the state of a QoS (quality of service) flow carrying user plane data transmission in the PDU session.

Further illustratively, the a-SMF determining that the first session is in the idle state before the preset timer expires includes: if the DNN field of the first session is "ims", determining that no QoS flow with a 5QI of 1 exists in the session before the preset timer expires; or, if the DNN field of the first session is "xxnet" or "xxmap", it is determined that the session has no user plane data to be transmitted before the preset timer expires.

And after the time that the first session is in the idle state is determined to reach the preset duration, and the preset timer is overtime, the A-SMF sends a command message to the terminal equipment, and starts and carries out a session release process. The specific implementation manner of sending the command message to the terminal device by the a-SMF refers to the related description in step S102, and is not described herein again.

Based on the above-mentioned scheme of steps S201-S202, after the a-SMF determines that the session path of the PDU session includes I-SMF, and the first session is in an active state, the a-SMF detects whether there is a PDU session in which the area where the I-SMF is located in the session path is different from the area where the a-SMF is located, so that path optimization is required, and starts a preset timer to wait for a period of time when the PDU session is converted from the active state to an idle state, and guarantees session and service continuity is achieved within the period of time before the preset timer is overtime, thereby avoiding missing possible services. And after the preset timer is overtime, if the session is determined to be in an idle state before the timer is overtime, session release is carried out, the terminal equipment is instructed to reestablish the session, and in the process of reestablishing the session, the route of the A-SMF of the roaming place and the route of the A-UPF of the roaming place which are more optimized are selected, and the I-SMF and the I-UPF do not need to be inserted, so that the roundabout path is avoided, and the session path optimization is realized.

In another implementation, an insertion session path request sent by an I-SMF is received before the A-SMF accepts and completes the insertion of the I-SMF in the session path. In order to solve the problem that an intermediate network element is not inserted into a session path, an embodiment of the present invention provides another session path optimization method, where an a-SMF network element decides to accept insertion of an I-SMF when receiving a session path insertion request sent by an I-SMF network element, and then initiates session release at an appropriate time. As shown in fig. 7, another session path optimization method provided in the embodiment of the present application includes S301 to S303:

s301, the A-SMF receives a request message of the I-SMF.

The request message comprises an identification of a first session of the terminal equipment and is used for requesting to insert the I-SMF in a session path of the first session.

Illustratively, the request message is a context request message (Namf _ pdusesion _ CreateSMContextRequest) in the session creation flow. In the Xn handover process triggered by UE movement, AMF decides to insert I-SMF in network according to the current position of UE and the service area (service area) of SMF. Since the session path of the first session does not yet include the I-SMF, a session creation context request message is invoked requesting that a session context be invoked from the a-SMF, thereby requesting that the I-SMF be inserted into the session path of the first session.

For example, when the number of the PDU sessions requested to be inserted into the intermediate network element is more than one, the request message may include a list of PDU session identifiers, where the list of PDU session identifiers includes an identifier of a PDU session requested to be inserted into the intermediate network element.

S302, if the A-SMF determines that the area where the I-SMF is located is different from the area where the A-SMF is located and the first session is in an activated state, the A-SMF accepts and completes the insertion of the I-SMF in the session path of the first session.

The description of the determination by the a-SMF that the region where the I-SMF is located is different from the region where the a-SMF is located may specifically refer to the related description in step S102, and details are not described here again. The description of the a-SMF determining that the first session is in the active state may specifically refer to the related description in step S101, and is not described herein again.

Illustratively, when the A-SMF receives a request for inserting a session path sent by the I-SMF, the A-SMF compares the I-SMF with the identification of the A-SMF to determine that the area where the I-SMF is located is different from the area where the I-SMF is located, and after the A-SMF determines to insert the intermediate network elements (I-SMF and I-UPF), the session path of the first session has a path detour, and the A-SMF determines that the session needs to be subjected to path optimization. But the A-SMF also detects that the first session is in an activated state at the same time, and determines that the I-SMF needs to be accepted to be inserted into the session path of the first session, otherwise, the ongoing service interruption is caused, and the normal use of the user is influenced, so that the insertion process of the I-SMF in the session path is accepted and completed.

Further exemplarily, the receiving and completing, by the a-SMF, the inserting of the I-SMF in the session path of the first session, which corresponds to the receiving of the request message by the a-SMF, specifically includes: the session creation context request message comprises tunnel information of the I-UPF, the A-SMF sends the tunnel information of the I-UPF to the A-UPF and informs of establishing a downlink tunnel between the A-UPF and the I-UPF; the I-SMF acquires a session context of a first session from the A-SMF; the I-SMF sends the tunnel information of the A-UPF to the I-UPF and informs the establishment of an uplink tunnel from the I-UPF to the A-UPF, so that an N9 tunnel between the A-UPF managed by the A-SMF and the I-UPF managed by the I-SMF is successfully established; the a-SMF returns a session creation context response message to the I-SMF.

After the N9 tunnel is successfully created, the process of creating and activating the end-to-end user plane path of the session may refer to the existing implementation manner, and details of the embodiment of the present application are not repeated.

In the process that the intermediate network elements I-SMF and I-UPF are inserted into the session path, the PDU session is kept in an activated state, and the service data transmission of the user is kept continuous without interruption.

And step S303, the A-SMF sends a command message to the terminal equipment under the condition that a preset condition is met.

The command message is used for instructing the terminal device to release the first session and establish a second session to a data network connected with the first session, and the preset conditions include: the first session transitions from an active state to an idle state.

The description of the a-SMF determining that the first session is converted from the active state to the idle state may specifically refer to the related description in step S102, and is not described herein again.

Illustratively, after the A-SMF accepts and completes the insertion of the I-SMF in the session path of the first session, event monitoring for the first session to be converted from the active state to the idle state is started, and once the first session is converted from the active state to the idle state, conditions for session path optimization are met. The specific implementation manner of sending the command message to the terminal device by the a-SMF refers to the related description in step S102, and is not described herein again.

Based on the scheme of the steps S301 to S303, the a-SMF receives a session path insertion request of the I-SMF, and the a-SMF determines that the area where the I-SMF is located is different from the area where the a-SMF is located, thereby determining that the PDU session needs to be subjected to path optimization, but the PDU session is in an active state, and if the insertion of the intermediate network element is rejected, the service data transmission is interrupted, thereby accepting and completing the insertion of the I-SMF; when the PDU conversation is converted from the active state to the idle state, the conversation is immediately released, the terminal equipment is instructed to rebuild the conversation, and in the process of rebuilding the conversation, the route is more optimized, the A-SMF of the roaming place and the A-UPF of the roaming place are selected, and the I-SMF and the I-UPF are not required to be inserted, so that the roundabout of the route is avoided, and the optimization of the conversation route is realized.

In step S303 of the above embodiment, the session release procedure is selected to be started immediately, and actually, in another implementation manner, in order to avoid missing a possible service, the session release procedure may also be selected to be started temporarily. Therefore, an embodiment of the present application further provides another session path optimization method, as shown in fig. 8, including S401 to S403:

step S401-step S402, which is the same as step S301-step S302 in the embodiment of FIG. 7.

S403(a), A-SMF determines that the first session is converted from the active state to the idle state, and then starts a preset timer.

Illustratively, the a-SMF determines that the PDU session is converted from the active state to the idle state, and has a condition for path optimization, but does not immediately start a session release procedure, but starts a preset timer to limit the effective time of the session path including the intermediate network element.

S403(b), the A-SMF determines that the first session is in an idle state before the preset timer is overtime, and the A-SMF sends a command message to the terminal equipment after the preset timer is overtime.

This step is the same as step S202(b) in the embodiment of fig. 6, and is not repeated here.

Based on the scheme of the steps S401 to S403, the a-SMF receives a session path insertion request of the I-SMF, and the a-SMF determines that the area where the I-SMF is located is different from the area where the a-SMF is located, thereby determining that the PDU session needs to be subjected to path optimization, but the PDU session is in an active state, and if the insertion of the intermediate network element is rejected, the service data transmission is interrupted, thereby accepting and completing the insertion of the I-SMF; and under the condition that the PDU session is converted into an idle state from an active state, starting a preset timer to wait for a period of time, and realizing the continuity of the session and the service in the period of time before the preset timer is overtime so as to avoid missing possible services. And after the preset timer is overtime, if the session is determined to be in an idle state before the timer is overtime, session release is carried out, the terminal equipment is instructed to reestablish the session, and in the process of reestablishing the session, the route of the A-SMF of the roaming place and the route of the A-UPF of the roaming place which are more optimized are selected, and the I-SMF and the I-UPF do not need to be inserted, so that the roundabout path is avoided, and the session path optimization is realized.

The embodiments shown in fig. 4-8 will be described in detail with reference to specific embodiments.

Fig. 9 is a schematic flow chart of a session path optimization method provided by the present application. The embodiment takes an IMS voice call service as an example, and after the I-SMF insertion is completed, the method for optimizing a session path corresponds to the method for optimizing a session path shown in fig. 4 to 6, where the method for optimizing a session path includes steps S501 to S5034:

s501, handover preparation.

The process of handover preparation may refer to an existing implementation manner, and is not described in detail in this embodiment of the present application.

And S502, switching execution.

The process of performing the handover may refer to an existing implementation manner, and is not described in detail in this embodiment of the present application.

S503, the target RAN sends a handover request to the AMF.

Illustratively, the target RAN, i.e., the RAN shown in fig. 2, is located in area 2, i.e., the access network equipment shown in fig. 3. The AMF, i.e. the AMF shown in fig. 2, located in area 2, i.e. the access and mobility management network element shown in fig. 3. The target RAN initiates an N2 path switching request (N2 path switch request) to the AMF, and requires the core network to cooperate with switching (handover).

S504, the AMF inserts the I-SMF according to the position decision requirement of the UE and selects the I-SMF.

Illustratively, if the current PDU session has no I-SMF, and the service area of the A-SMF does not include the current Time Advance (TA) of the UE, and the UE moves from the service area of the A-SMF to the service area of the I-SMF, the I-SMF insertion process is performed. The AMF selects one I-SMF according to parameters of single network slice selection assistance information (S-NSSAI) and the position (such as TA) of the UE.

S505, the AMF sends a session creation request (Namf _ PDSUSessionCreateSCContextrequest) to the I-SMF.

The session creation request message carries a context reference identifier (smContextRef) of the A-SMF, and carries an upCnxState (indicating to establish N3 tunnel user plane resources) according to a UE indication, and is used for requesting the I-SMF to create a context of the PDU session.

S505, the I-SMF acquires the session context from the A-SMF.

S506, the I-SMF selects the I-UPF and establishes the N4 session.

Illustratively, the I-SMF instructs the I-UPF to establish a downstream tunnel to the A-UPF by sending an N4 session establishment request (N4 session establishment request) to the I-UPF, informing the I-UPF of the N9 tunnel information assigned to the A-UPF, the N3 tunnel information to the RAN, etc.

S508, the I-SMF sends a session creation request (Namf _ PDSUSessionCreateSCContext request) to the A-SMF.

Illustratively, the session creation request message carries the identifier of the I-SMF, and is used to request the creation of a session including the I-SMF, i.e. to insert the I-SMF in the session path of the PDU session.

S509, the A-SMF instructs the A-UPF to modify the N4 session.

Illustratively, the A-SMF instructs the A-UPF to establish an upstream tunnel to the I-UPF by sending an N4 session establishment request (N4 session establishment request) to the A-UPF informing the I-UPF of the N9 tunnel information assigned to the A-UPF.

S5010, the a-UPF sends an N3 termination point (N3 end marker) packet to the source RAN, which forwards the packet to the target RAN.

S5011, the A-SMF replies a session creation Response (Namf _ PDUSESION _ CreateSSCONText Response) to the I-SMF.

S5012, the I-SMF replies a session creation Response (Namf _ PDScession _ Create SMContext Response) to the AMF.

S5013, the AMF sends a handover confirm message to the target RAN.

S5014, completing the handover, and releasing the resource of the source RAN.

Note that, in the following steps from this step, the RAN refers to only the target RAN.

S5015, the A-SMF detects that the PDU session is inserted into the I-SMF in different areas, the current UE is in conversation, and event monitoring is started.

The method comprises the steps that A-SMF detects that a session path of PDU session comprises I-SMF, and the area where the I-SMF is located is different from the area where the A-SMF is located by comparing network element example marks, namely UE is currently in a roaming state, and then the current session is determined to need path optimization; but detecting that the current PDU session has a QoS flow with 5QI being 1, starting event monitoring, and after waiting for the release event of the QoS flow with 5QI being 1, triggering a session release flow to reestablish the session.

S5016, the UE terminates the call.

S5017, the UE triggers session modification to request to delete the 5QI ═ 1 flow, and the AMF sends the request to the I-SMF and the a-SMF by invoking the PDU session update service.

S5018, the I-SMF and the A-SMF return session update responses to the AMF.

S5019, the AMF sends the session update response message obtained from the SMF to the RAN via the N2 message, including the session modification command.

S5020, the RAN initiates an air interface resource modification process according to the received updated QoS parameters, updates air interface resources related to the session modification, and sends a session modification completion message to the UE.

S5021, the RAN sends an N2 interface response message to the AMF.

S5022, the AMF forwards the confirmation message of the completion of the RAN session modification to the I-SMF and the A-SMF by calling the PDU session update service.

S5023, the A-SMF detects the flow release event to start the release flow of the IMS PDU session and instructs the UE to rebuild the PDU session.

As shown in fig. 9, step S5023 may be replaced by steps S5023(a) and S5023(b), that is, the a-SMF detects a flow release event to start a release procedure of the IMS PDU session, starts a timer T1 to wait for a period of time, and starts a release procedure of the IMS PDU session after the timer expires if the UE does not access the voice call connection any more during the period of time, and instructs the UE to re-establish the PDU session.

S5024, the A-SMF sends a session modification request to the I-SMF.

The Session modification request message carries a Session release command message (PDU Session release command), which includes a PDU Session ID and a cause indication (cause indication), and indicates the terminal to reestablish the PDU Session to the same DNN.

S5025, the I-SMF calls the N1/N2 messaging service of the AMF, and sends the N1/N2 interface release message to the AMF.

The N1/N2 interface Release message carries a PDU Session Release Command, which includes a PDU Session ID and Cause indication, and indicates the terminal to reestablish the PDU Session to the same DN.

S5026, the AMF sends the N1/N2 interface release message acquired from the SMF to the RAN through the N2 message.

S5027, the RAN sends the Session release request message to the UE, and releases the air interface resource allocated for the PDU Session.

The Session Release request message carries a PDU Session Release Command, which includes a PDU Session ID and a Cause indication, and instructs the terminal to reestablish the PDU Session to the same DN.

S5028, the RAN sends an N2 response message to the AMF.

S5029, the AMF invokes the PDU session update service to send the N2 reply message received from the RAN to the I-SMF.

S5030, the I-SMF replies a session update response to the A-SMF.

S5031, the SMF sends a session release notification event to the I-SMF and the AMF, and releases the related session binding relation on the AMF.

S5032, the UE initiates a session establishment request to the AMF.

The session establishment request message includes: session flag (PDU Session ID), Session type (IPV6 type), SSC mode (SSC mode1), DNN (the same DNN as the released old PDU Session).

S5033, SMF selection.

And the AMF selects the SMF with the closest path for the new PDU session (namely the SMF in the local area of the UE roaming local area, the local province and the local area) according to the DNN, the S-NSSAI, the subscription data and the like.

S5034, PDU conversation establishment flow.

The subsequent step is the process of establishing the synchronous network PDU session, which comprises the following steps: the AMF calls the session service of the selected NEW A-SMF to trigger session establishment; the new A-SMF acquires the subscription data of session management from the UDM and selects PCF and PSA UPF for the session; establishing session management policy connection between the SMF and the PCF, and acquiring a session policy rule; the new A-SMF establishes end-to-end user interface connection among the UE, the RAN and the UPF; SMF registers to UDM, and the UDM records SMF mark corresponding to the session; the SMF or UPF allocates IPV6 prefix for the UE, and sends the prefix to the UE through the user plane.

Based on the scheme of the above steps S501 to S5034, by enhancing the function of the a-SMF network element, the a-SMF network element initiates session release when it is determined that the area where the I-SMF is located is different from the area where the a-SMF is located and the session is converted from the active state to the idle state (and after the session is in the idle state for a preset time), and instructs the terminal device to establish a new PDU session to access the same data network, and in the process of session reestablishment, the a-SMF of the roaming place and the a-UPF of the roaming place which are more optimized in routing are selected, and the I-SMF and the I-UPF do not need to be inserted, so as to optimize the path of the PDU session, and solve the problem of path detour existing in the service using SSC mode1 in the operator policy without affecting the continuity of the session and the service.

Fig. 10 is a schematic flow chart of another session path optimization method provided in the present application. The embodiment takes an IMS voice call service as an example, and is applied to an I-SMF insertion process, and corresponds to the session path optimization method shown in fig. 7 to 8, where the session path optimization method includes steps S601 to S6034:

steps S601-S608 are the same as steps S501-S508 in the embodiment of fig. 9.

S609(a), the A-SMF detects that the session request is inserted into the I-SMF in different areas, and the current UE is in conversation.

The A-SMF detects that a PDU session request inserts I-SMF in a session path according to a received session creation request, and determines that an area where the I-SMF is located is different from an area where the A-SMF is located by comparing network element example identifiers, namely that the UE is currently in a roaming state, and then determines that the current session needs path optimization; but detects that there is a QoS flow of 5QI ═ 1 in the current PDU session, the insertion of I-SMF is accepted and completed.

S609(b), A-SMF instructs A-UPF to modify the N4 session.

Steps S6010-S6014 are the same as steps S5010-S5014 of the example of FIG. 9.

S6015, A-SMF starts event monitoring.

And after the A-SMF determines that the I-SMF is inserted completely, starting event monitoring, and after waiting for a QoS flow release event with 5QI being 1, triggering a session release flow to reestablish the session.

Steps S6016-S6034 are the same as steps S5016-S5034 of the embodiment of FIG. 9.

Based on the scheme of the steps S601-S6034, the a-SMF receives a session path insertion request of the I-SMF, and the a-SMF determines that the area where the I-SMF is located is different from the area where the a-SMF is located, thereby determining that the PDU session needs to be subjected to path optimization, but the PDU session is in a call state, and if the insertion of the intermediate network element is rejected, the service data transmission is interrupted, thereby accepting and completing the insertion of the I-SMF; when the PDU conversation is converted from the conversation state to the idle state, the conversation is released immediately (or the conversation is released after the idle state reaches the preset duration), the terminal equipment is instructed to rebuild the conversation, and in the process of rebuilding the conversation, the route of the A-SMF of the roaming place and the A-UPF of the roaming place which are more optimized are selected, and the I-SMF and the I-UPF are not required to be inserted, so that the roundabout of the route is avoided, and the conversation route optimization is realized.

The above-mentioned scheme provided by the embodiment of the present invention is introduced mainly from the perspective that the session path optimization device is used as an anchor point session management network element. It will be appreciated that the session management network element, in order to implement the above-described functions, comprises corresponding hardware structures and/or software modules for performing the respective functions. Those skilled in the art will readily appreciate that the present invention can be implemented in hardware or a combination of hardware and computer software, in conjunction with the anchor session management network elements and algorithm steps of the examples described in connection with the embodiments disclosed herein. Whether a function is performed as hardware or computer software drives hardware depends upon the particular application and design constraints imposed on the solution. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present invention.

In the embodiment of the present invention, the session path optimization device may be divided into the functional modules or the functional units according to the above method examples, for example, each functional module or functional unit may be divided corresponding to each function, or two or more functions may be integrated into one processing module. The integrated module may be implemented in a form of hardware, or may be implemented in a form of a software functional module or a functional unit. The division of the modules or units in the embodiments of the present invention is schematic, and is only a logic function division, and there may be another division manner in actual implementation.

Fig. 11 shows a possible structural schematic diagram of the session path optimizing apparatus in the foregoing embodiment, in a case that each function module is divided according to each function. The session path optimization device comprises a processing module 701 and a sending module 702.

The processing module 701 is configured to determine that a session path of a first session includes an intermediate session management network element I-SMF, and the first session is in an active state;

the processing module 701 is further configured to determine whether a preset condition is met; wherein the preset conditions include: the A-SMF determines that the I-SMF is in a different region than the A-SMF, and the first session transitions from an active state to an idle state.

The sending module is used for sending a command message to the terminal equipment under the condition that the preset condition is met; the command message is used for instructing the terminal equipment to release the first session and establish a second session to a data network connected with the first session.

Optionally, the preset condition further includes: and the time that the first session is in the idle state reaches a preset time length.

Optionally, if the first session is an IP multimedia subsystem IMS service session, the first session is in an activated state, which means that: the first session has a data flow with 5G service quality identification 5QI ═ 1; the first session is converted from an active state to an idle state, which means that: and releasing the 5 QI-1 data flow of the first session is completed.

Optionally, if the first session is a data service session, the first session is in an active state, which means that: the first session has a data stream for bearing data transmission; the first session is converted from an active state to an idle state, which means that: and completing the release of the data flow of the bearer data transmission of the first session.

Optionally, the processing module 701 is specifically configured to: and determining that the area where the I-SMF is positioned is different from the area where the A-SMF is positioned according to the identification of the I-SMF and the identification of the A-SMF.

Optionally, the area where the I-SMF is located is different from the area where the a-SMF is located, including one of the following situations: the A-SMF and the I-SMF belong to different large regions; or, the A-SMF and the I-SMF belong to the same large region but belong to different provinces; or the A-SMF and the I-SMF belong to the same province but different province regions.

The session path optimization device provided by the embodiment of the invention comprises: the device comprises a processing module and a sending module. The processing module is used for determining that a session path of a first session comprises an intermediate session management network element I-SMF, and the first session is in an activated state; the processing module is further used for determining whether a preset condition is met; wherein the preset conditions include: the A-SMF determines that the area where the I-SMF is located is different from the area where the A-SMF is located, and the first session is converted from an active state to an idle state; the sending module is used for sending a command message to the terminal equipment under the condition that the preset condition is met; the command message is used for instructing the terminal equipment to release the first session and establish a second session to a data network connected with the first session. Compared with the prior art, the session path detour is caused by inserting the I-SMF and the I-UPF into the session path while keeping the user plane anchor point UPF unchanged. The session path optimization device provided by the invention initiates session release when determining that the area where the I-SMF is located is different from the area where the A-SMF is located and the session is converted from the active state to the idle state, and instructs the terminal equipment to establish a new PDU session to access the same data network, and during session reestablishment, the A-SMF of a roaming place and the A-UPF of the roaming place with more optimized routing are selected, and the I-SMF and the I-UPF are not required to be inserted, so that the path of the PDU session is optimized, and the problem of path detour of the service adopting SSC mode1 in an operator strategy is solved under the condition of not influencing the continuity of the session and the service.

In another embodiment of the present invention, another session path optimization apparatus is provided, and in a case that each function module is divided according to each function, fig. 12 shows a schematic diagram of a possible structure of the session path optimization apparatus in the foregoing embodiment. The session path optimization device comprises a receiving module 801, a processing module 802 and a sending module 803.

The receiving module 801 is configured to receive a request message of an intermediate session management network element I-SMF, where the request message is used to request that the I-SMF is inserted into a session path of a first session.

The processing module 802 is configured to accept and complete inserting the I-SMF into the session path of the first session if the a-SMF determines that the I-SMF is located in a different area than the a-SMF and the first session is in an active state.

The processing module 802 is further configured to determine whether a preset condition is met; wherein the preset conditions include: the first session is transitioned from an active state to an idle state.

The sending module 803 is configured to send a command message to the terminal device when the preset condition is met; the command message is used for instructing the terminal equipment to release the first session and establish a second session to a data network connected with the first session.

Optionally, the processing module 802 is specifically configured to: and determining that the area where the I-SMF is positioned is different from the area where the A-SMF is positioned according to the identification of the I-SMF and the identification of the A-SMF.

In the session path optimization device provided by the embodiment of the invention, the A-SMF determines that the session path of the PDU session comprises the I-SMF, and after the first session is in the activated state, the A-SMF detects whether the PDU session needing path optimization exists in the session path in which the area of the I-SMF is different from the area of the A-SMF, and starts the preset timer to wait for a period of time under the condition that the PDU session is converted from the activated state to the idle state, so that the continuity of the session and the service is ensured in the period of time before the preset timer is overtime, and possible services are prevented from being missed. And after the preset timer is overtime, if the session is determined to be in an idle state before the timer is overtime, session release is carried out, the terminal equipment is instructed to reestablish the session, and in the process of reestablishing the session, the route of the A-SMF of the roaming place and the route of the A-UPF of the roaming place which are more optimized are selected, and the I-SMF and the I-UPF do not need to be inserted, so that the roundabout path is avoided, and the session path optimization is realized.

Fig. 13 shows a schematic structural diagram of still another possible session path optimization device involved in the above embodiment. The session path optimization device includes: a processor 901 and a communication interface 903. The processor 901 is configured to control and manage the actions of the session path optimization device, for example, to perform the steps performed by the processing module 701 or the processing module 802 described above, and/or to perform other processes of the techniques described herein. The communication interface 903 is used for supporting communication between the session path optimization apparatus and other network entities, for example, the steps executed by the sending module 702, the receiving module 801, and the sending module 803 are executed. The session path optimizing device may further comprise a memory 902 and a bus 904, the memory 902 being for storing program codes and data of the session path optimizing device.

The processor 901 may be, among other things, an implementation or execution of the various illustrative logical blocks, modules, and circuits described in connection with the disclosure herein. The processor may be a central processing unit, general purpose processor, digital signal processor, application specific integrated circuit, field programmable gate array or other programmable logic device, transistor logic device, hardware component, or any combination thereof. Which may implement or perform the various illustrative logical blocks, modules, and circuits described in connection with the disclosure. The processor may also be a combination of computing functions, e.g., comprising one or more microprocessors, DSPs, and microprocessors, among others.

The memory 902 may be a memory in the speech path optimizing apparatus, and the like, and the memory may include a volatile memory, such as a random access memory; the memory may also include non-volatile memory, such as read-only memory, flash memory, a hard disk, or a solid state disk; the memory may also comprise a combination of memories of the kind described above.

The bus 904 may be an Extended Industry Standard Architecture (EISA) bus or the like. The bus 904 may be divided into an address bus, a data bus, a control bus, and the like. For ease of illustration, only one thick line is shown in FIG. 13, but this is not intended to represent only one bus or type of bus.

Through the above description of the embodiments, it is clear to those skilled in the art that, for convenience and simplicity of description, the foregoing division of the functional modules is merely used as an example, and in practical applications, the above function distribution may be completed by different functional modules according to needs, that is, the internal structure of the device may be divided into different functional modules to complete all or part of the above described functions. For the specific working processes of the system, the apparatus and the unit described above, reference may be made to the corresponding processes in the foregoing method embodiments, and details are not described here again.

The present application provides a computer program product containing instructions, which when run on a computer, causes the computer to execute the session path optimization method described in the above method embodiments.

An embodiment of the present application further provides a computer-readable storage medium, where instructions are stored in the computer-readable storage medium, and when the session path optimization device executes the instructions, the device executes each step executed by the anchor session management network element in the method flow shown in the foregoing method embodiment.

The computer readable storage medium may be, for example, but not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any combination thereof. More specific examples (a non-exhaustive list) of the computer readable storage medium would include the following: an electrical connection having one or more wires, a portable computer diskette, a hard disk, a Random Access Memory (RAM), a Read-Only Memory (ROM), an Erasable Programmable Read-Only Memory (EPROM), a register, a hard disk, an optical fiber, a portable Compact Disc Read-Only Memory (CD-ROM), an optical storage device, a magnetic storage device, any suitable combination of the above, or any other form of computer readable storage medium known in the art. An exemplary storage medium is coupled to the processor such the processor can read information from, and write information to, the storage medium. Of course, the storage medium may also be integral to the processor. The processor and the storage medium may reside in an Application Specific Integrated Circuit (ASIC). In embodiments of the present application, a computer readable storage medium may be any tangible medium that can contain, or store a program for use by or in connection with an instruction execution system, apparatus, or device.

The above description is only an embodiment of the present application, but the scope of the present application is not limited thereto, and any changes or substitutions within the technical scope of the present disclosure should be covered by the scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims

1. A method for session path optimization, comprising:

the anchor point conversation management network element A-SMF determines that a conversation path of a first conversation comprises an intermediate conversation management network element I-SMF, and the first conversation is in an activated state;

under the condition that a preset condition is met, the A-SMF sends a command message to the terminal equipment; the command message is used for indicating the terminal equipment to release the first session and establishing a second session to a data network connected with the first session; the preset conditions include: the A-SMF determines that the I-SMF is in a different region than the A-SMF, and the first session transitions from an active state to an idle state.

2. The method according to claim 1, wherein the preset condition further comprises: and the time that the first session is in the idle state reaches a preset time length.

3. A method for session path optimization, comprising:

an anchor point conversation management network element A-SMF receives a request message of an intermediate conversation management network element I-SMF; the request message is used for requesting to insert the I-SMF in a session path of a first session;

if the A-SMF determines that the I-SMF is in a different area than the A-SMF and the first session is active, the A-SMF accepts and completes inserting the I-SMF in the session path of the first session;

under the condition that a preset condition is met, the A-SMF sends a command message to the terminal equipment; the command message is used for indicating the terminal equipment to release the first session and establishing a second session to a data network connected with the first session; the preset conditions include: the first session is transitioned from an active state to an idle state.

4. The method of claim 3, wherein the preset condition further comprises: and the time that the first session is in the idle state reaches a preset time length.

5. The method according to any one of claims 1 to 4,

if the first session is an IP multimedia subsystem IMS service session, the first session is in an active state, which means that: the first session has a data flow with 5G service quality identification 5QI ═ 1; the first session is converted from an active state to an idle state, which means that: and releasing the 5 QI-1 data flow of the first session is completed.

6. The method according to any one of claims 1 to 4,

if the first session is a data service session, the first session is in an activated state, which means that: the first session has a data stream for bearing data transmission; the first session is converted from an active state to an idle state, which means that: and completing the release of the data flow of the bearer data transmission of the first session.

7. The method of any of claims 1-4, wherein the A-SMF determining that the I-SMF is in a different region than the A-SMF comprises:

and the A-SMF determines that the area where the I-SMF is positioned is different from the area where the A-SMF is positioned according to the identification of the I-SMF and the identification of the A-SMF.

8. The method of any of claims 1-4, wherein the I-SMF is located in a different area than the a-SMF, including one of:

the A-SMF and the I-SMF belong to different large regions; alternatively, the first and second electrodes may be,

the A-SMF and the I-SMF belong to the same large region but belong to different provinces; alternatively, the first and second electrodes may be,

the A-SMF and the I-SMF belong to the same province but different province regions.

9. A session path optimization apparatus, wherein the session path optimization apparatus, as an anchor session management network element a-SMF, comprises:

the processing module is used for determining that a session path of a first session comprises an intermediate session management network element I-SMF, and the first session is in an activated state;

the processing module is further used for determining whether a preset condition is met; wherein the preset conditions include: the A-SMF determines that the area where the I-SMF is located is different from the area where the A-SMF is located, and the first session is converted from an active state to an idle state;

10. The apparatus of claim 9, wherein the preset condition further comprises: and the time that the first session is in the idle state reaches a preset time length.

11. A session path optimization apparatus, wherein the session path optimization apparatus, as an anchor session management network element a-SMF, comprises:

a receiving module, configured to receive a request message of an intermediate session management network element I-SMF; the request message is used for requesting to insert the I-SMF in a session path of a first session;

a processing module, configured to accept and complete inserting the I-SMF in a session path of the first session if the a-SMF determines that the I-SMF is located in a different area than the a-SMF and the first session is in an active state;

the processing module is further used for determining whether a preset condition is met; wherein the preset conditions include: the first session is converted from an active state to an idle state;

12. The apparatus of claim 11, wherein the preset condition further comprises: and the time that the first session is in the idle state reaches a preset time length.

13. The apparatus according to any one of claims 9 to 12,

14. The apparatus according to any one of claims 9 to 12,

15. The apparatus according to any one of claims 9 to 12, wherein the processing module is specifically configured to: and determining that the area where the I-SMF is positioned is different from the area where the A-SMF is positioned according to the identification of the I-SMF and the identification of the A-SMF.

16. The apparatus of any of claims 9-12, wherein the I-SMF is located in a different area than the a-SMF, including one of:

17. A session path optimization apparatus, comprising: a processor, a communication interface, a bus, and a memory; wherein the memory is used for storing one or more programs, the one or more programs comprising computer executable instructions which, when the session path optimization device is running, the processor executes the computer executable instructions stored in the memory to cause the session path optimization device to perform the session path optimization method of any one of claims 1 to 8.

18. A computer-readable storage medium having stored therein instructions which, when executed by a computer, cause the computer to perform the session path optimization method of any one of claims 1 to 8.