Communication method, apparatus and system

Abstract

The present disclosure relates to the technical field of mobile communications, and provides a communication method, apparatus and system. The communication method is executed by a session management function network element in a home network, and comprises: obtaining that a fault occurs to a first user plane function network element in a home network, the first user plane function network element being deployed in a visited network; releasing a first home routed protocol data unit (HR PDU) session established for a user equipment via the first user plane function network element; and establishing a second HR PDU session for the user equipment via a second user plane function network element in the home network, the second user plane function network element being deployed in the home network. The method allows to implement a user plane function network element fault handling process in a new roaming scenario, thereby ensuring the service continuity.

Description

A communication method, apparatus and system

[0001] Cross Reference to Related Applications

[0002] The present disclosure claims priority to the Chinese patent application No. 202411354512.8, filed on September 26, 2024, and entitled “A communication method, apparatus and system”, the entire contents of which are incorporated herein by reference in its entirety. TECHNICAL FIELD

[0003] The present disclosure relates to the field of mobile communication technology, and in particular, to a communication method, apparatus and system. BACKGROUND

[0004] The roaming scenarios are mainly divided into local breakout / routing roaming (Local Breakout) and home routing (Home Routed, HR). Currently, only the case that the home user plane function (H-UPF) is deployed in the home public land mobile network (Home Public Land Mobile Network, HPLMN) is supported in the two scenarios.

[0005] In the related art, for the home routing roaming scenario, the 5G system supports the HR-SBO (Home-Routed Session BreakOut) mechanism, that is, the data is shunted through the visited user plane function (V-UPF) in the visited public land mobile network (Visited Public Land Mobile Network, VPLMN). However, the data shunting through the V-UPF is not conducive to the control and management (such as charging management, etc.) of the roaming data by the HPLMN. SUMMARY

[0006] The present disclosure provides a communication method, apparatus and system.

[0007] According to a first aspect of the present disclosure, a communication method is provided, comprising: learning that a first user plane function network element in the home network fails, wherein the first user plane function network element is deployed in a visited place; releasing a first home routing protocol data unit (HR PDU) session established for a user equipment via the first user plane function network element; and establishing a second HR PDU session for the user equipment via a second user plane function network element in the home network, wherein the second user plane function network element is deployed in a home place.

[0008] In some embodiments, the establishing the second HRPDU session via the second user plane function network element in the home network comprises: selecting the second user plane function network element; sending a session request to the second user plane function network element; receiving a session response from the second user plane function network element.

[0009] In some embodiments, the establishing the second HRPDU session via the second user plane function network element in the home network further comprises: updating the locally stored session context information.

[0010] In some embodiments, the updating the locally stored session context information comprises: updating information of a domain name system (DNS) server corresponding to the first HRPDU session to information of a DNS server corresponding to the second HRPDU session, the DNS server corresponding to the first HRPDU session being deployed in the visited network, the DNS server corresponding to the second HRPDU session being deployed in the home network; and / or updating user plane path information corresponding to the first HRPDU session to user plane path information corresponding to the second HRPDU session.

[0011] In some embodiments, the selecting the second user plane function network element comprises: selecting the second user plane function network element from user plane function network elements belonging to the home network and deployed in the home network, in a case that there is no other user plane function network element belonging to the home network except the first user plane function network element in the visited network, or there is the other user plane function network element in the visited network but the other user plane function network element does not satisfy a set selection condition.

[0012] In some embodiments, the communication method further comprises: in a case that there is a network element satisfying the selection condition in the other user plane function network elements, establishing a third HRPDU session for the user equipment via the network element satisfying the selection condition.

[0013] In some embodiments, the updating the user plane path information corresponding to the first HRPDU session to the user plane path information corresponding to the second HRPDU session comprises: updating uplink splitter information and PDU session anchor point information corresponding to the first HRPDU session to uplink splitter information and PDU session anchor point information corresponding to the second HRPDU session.

[0014] In some embodiments, the first user plane function network element supports uplink splitter function and PDU session anchor point function established for the first HRPDU session.

[0015] In some embodiments, the learning the first user plane function network element in the home network fails comprises: receiving a failure report from the first user plane function network element; and determining the first user plane function network element fails according to the failure report.

[0016] In some embodiments, the failure report carries an identity of a visited network.

[0017] According to a second aspect of the present disclosure, a communication apparatus is provided, which is arranged in a session management function network element in a home network, comprising: a learning module configured to learn a first user plane function network element in the home network fails, wherein the first user plane function network element is deployed in a visited network; a session releasing module configured to release a first home routed protocol data unit, HRPDU, session established for a user equipment via the first user plane function network element; and a session establishing module configured to establish a second HRPDU session for the user equipment via a second user plane function network element in the home network, wherein the second user plane function network element is deployed in the home network.

[0018] According to a third aspect of the present disclosure, a communication apparatus is provided, comprising: a memory; and a processor coupled to the memory, the processor is configured to execute a communication method as previously described based on instructions stored in the memory.

[0019] According to a fourth aspect of the present disclosure, a communication system is provided, comprising: a session management function network element in a home network, comprising a communication apparatus as previously described; the first user plane function network element configured to assist the session management function network element to release a first HRPDU session; and the second user plane function network element configured to assist the session management function network element to establish a second HRPDU session.

[0020] According to a fifth aspect of the present disclosure, a computer readable storage medium is provided, which stores computer program instructions, the instructions being executed by a processor to implement a communication method as previously described.

[0021] According to a sixth aspect of the present disclosure, a computer program product is provided, which stores computer program instructions, the instructions being executed by a processor to implement a communication method as previously described.

[0022] Other features and advantages of the present disclosure will be apparent from the following detailed description of exemplary embodiments thereof, taken in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF DRAWINGS

[0023] The accompanying drawings, which constitute a part of this specification, illustrate embodiments of the present disclosure and, together with the description, serve to explain the principles of the present disclosure.

[0024] FIG. 1 is a schematic diagram of a system architecture in a roaming scenario, according to some embodiments of the present disclosure;

[0025] FIG. 2 is a schematic diagram of a communication method, according to some embodiments of the present disclosure;

[0026] FIG. 3 is a schematic diagram of a communication method, according to some other embodiments of the present disclosure;

[0027] FIG. 4 is a schematic diagram of a structure of a communication apparatus, according to some embodiments of the present disclosure;

[0028] FIG. 5 is a schematic diagram of a structure of a communication apparatus, according to some other embodiments of the present disclosure;

[0029] FIG. 6 is a schematic diagram of a structure of a communication system, according to some embodiments of the present disclosure.

[0030] The present disclosure can be more clearly understood and appreciated from the following detailed description, taken in conjunction with the following drawings of which: DETAILED DESCRIPTION

[0031] Various exemplary embodiments of the present disclosure will now be described in detail by way of specific example with reference to the drawings. It should be noted that the relative arrangement, numerical expressions, and numerical values of the components and steps set forth in these embodiments are not intended to limit the scope of the present disclosure unless otherwise specifically stated.

[0032] It should be noted that the size of each part shown in the drawings is not necessarily drawn to scale for the purpose of convenience of description.

[0033] The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the scope of the present disclosure and its applications or uses.

[0034] Techniques, methods, and apparatus known to those of ordinary skill in the relevant art can not be discussed in detail herein. However, where appropriate, such techniques, methods, and apparatus can be considered as part of the present disclosure.

[0035] In all of the examples shown and discussed herein, any specific values should be interpreted as merely illustrative and not as a limitation on the scope of the exemplary embodiments. Thus, other examples of the exemplary embodiments can have different values.

[0036] It should be noted that like numbers and letters refer to like items throughout the drawings, and that, once an item is defined in one drawing, it should not require further discussion in subsequent drawings.

[0037] In order to make the objects, technical solutions, and advantages of the present disclosure clearer, the present disclosure will be further described in detail below with reference to specific embodiments and with reference to the accompanying drawings.

[0038] In the related art, the roaming data is split by the V-UPF, which is not conducive to the control and management of the home network to the roaming data. The inventor of the present disclosure finds that the roaming data can only be split by the V-UPF in the current roaming scenario, which is caused by the fact that the current communication system only supports deploying the H-UPF in the home network.

[0039] In view of this, the present disclosure proposes a new communication method, device and system, which can support splitting the roaming data by the H-UPF and guarantee the continuity of services when the H-UPF fails.

[0040] FIG. 1 is a schematic diagram of a system architecture in a roaming scenario according to some embodiments of the present disclosure. As shown in FIG. 1, the system architecture of the embodiments of the present disclosure includes a visited public land mobile network (VPLMN) and a home public land mobile network (HPLMN).

[0041] The VPLMN includes a user equipment (UE), a radio access network (RAN), an access and mobility management function (AMF), a user plane function (UPF), a session management function (SMF), and the like. The HPLMN includes an SMF, a UPF, and the like. In order to distinguish the functions in the two networks, the prefix "H" or "V" is used for distinction. For example, the user plane function in the VPLMN is called V-UPF, and the user plane function in the HPLMN is called H-UPF.

[0042] The main difference between the system architecture in the embodiments of the present disclosure and the related art is that the H-UPF is deployed in the visited network. For example, the H-UPF is deployed in the visited network by cloud technology.

[0043] In the HR roaming scenario, a first home routed protocol data unit (HR PDU) session is established for a UE moving to a visited location via a V-UPF and a H-UPF located in the visited location. The H-UPF deployed in the visited location can include a PDU session anchor (PSA) and an uplink classifier (UL CL). In implementation, the PSA and the UL CL can be deployed on different devices or on the same device (e.g., the same network element). For a data flow of the first HR PDU session, the data flow can be sent by the UE to the V-UPF, sent by the V-UPF to the H-UPF as the UL CL, sent by the H-UPF as the UL CL to the H-UPF as the PSA, and sent by the H-UPF as the PSA to a data network.

[0044] FIG. 2 is a flow diagram of a communication method according to some embodiments of the present disclosure. As shown in FIG. 2, the communication method includes steps S21-S23.

[0045] In step S21, a first user plane function network element in a home network is learned to be faulty.

[0046] In some embodiments of the present disclosure, the communication method can be performed by a session management function network element in the home network. The session management function network element in the home network can be, for example, an H-SMF network element.

[0047] The first user plane function network element is deployed in a visited location. For example, the first user plane function network element can be an H-UPF network element deployed in the visited location. For example, the first user plane function network element can be a network element supporting a PSA function deployed in the visited location, or an H-UPF network element supporting both a PSA function and an UL CL function.

[0048] The session management function network element in the home network can determine whether the first user plane function network element is faulty in multiple ways. Two determination methods are exemplarily described below.

[0049] In the first determination method, the session management function network element in the home network receives a fault report from the first user plane function network element, and determines that the first user plane function network element is faulty based on the fault report.

[0050] In some examples, the failure report carries an identity of the visited network. For example, the identity of the visited network is an identity of a VPLMN. The session management function network element in the home network can determine which H-UPF network element in which visited network has failed according to the identity of the visited network after receiving the failure report.

[0051] In other examples, the failure report carries an identity of the visited network and an identity of the first user plane function network element. The session management function network element in the home network can accurately determine which H-UPF network element in which visited network has failed according to the information in the failure report after receiving the failure report. In addition, in specific implementation, the failure report can also carry a failure type and the like.

[0052] In the second determination manner, the session management function network element in the home network receives a failure report sent by a network element (such as a V-SMF network element) other than the first user plane function network element, and determines that the first user plane function network element has failed according to the failure report. In addition, in specific implementation, the session management function network element in the home network can also determine whether the first user plane function network element has failed in other manners.

[0053] In step S22, the first HRPDU session established for the user equipment via the first user plane function network element is released.

[0054] The user equipment is a device that is subscribed to the home network and is located in a visited place (or a visited network). The user equipment, also referred to as a terminal or a terminal device, is a device with wireless transceiving function, which can communicate with one or more core networks via an access network device in the access network.

[0055] In some examples, the session management function network element in the home network manages the session of the user equipment in a session and service continuity mode 2 (SSC mode 2). In these examples, step S22 is performed first, and then step S23 is performed.

[0056] In other examples, the session management function network element in the home network manages the session of the user equipment in a session and service continuity mode 3 (SSC mode 3). In these examples, step S23 is performed first, and then step S22 is performed.

[0057] In some examples, the session management function network element in the home network determines the session and service continuity mode corresponding to the user equipment first; and performs steps S22 and S23 according to the session and service continuity mode corresponding to the user equipment.

[0058] In some examples, the process of releasing the first HR PDU session includes: the H-SMF network element sending an N4 session release request to the first UPF network element to instruct the first UPF network element to release the session-related resources; receiving an N4 session release response sent by the first UPF network element; and the H-SMF network element sending a session release instruction to a session management function (V-SMF) network element in the visited network to release the session-related resources through the V-SMF network element. In addition, in specific implementation, the session release process can further include a signaling process between the V-SMF network element and an access and mobility management function (V-AMF) network element in the visited network, and a signaling process between the V-AMF network element and the UE, so that the network elements involved in the first HR PDU session release corresponding resources. For the signaling process between these network elements, reference can be made to the related content in 3GPP about session release.

[0059] Exemplarily, the first HR PDU session can be a session with an uplink splitter function inserted, and the uplink splitter function is implemented through the first user plane function network element. In these examples, the process of releasing the first HR PDU session includes: deleting the locally stored ULCL node information and PSA node information corresponding to the first HR PDU session.

[0060] In step S23, a second HR PDU session via a second user plane function network element in the home network is established for the user equipment.

[0061] The second user plane function network element is deployed in the home network. For example, the second user plane function network element can be an H-UPF network element deployed in the home network.

[0062] In some examples, the session management function network element in the home network establishing the second HR PDU session includes: selecting the second user plane function network element; sending a session request to the second user plane function network element; and receiving a session response from the second user plane function network element. In addition, establishing the second HR PDU session can further include the following steps: updating the locally stored session context information.

[0063] The selection of the second user plane function network element can be implemented in various exemplary ways. The following describes two exemplary ways.

[0064] In the first exemplary way, selecting the second user plane function network element includes: selecting the second user plane function network element from a plurality of user plane function network elements deployed in the home network and belonging to the home network according to a set selection condition.

[0065] In the second exemplary manner, selecting the second user plane function network element includes: determining whether there is, in the visited place, a user plane function network element belonging to the home network and other than the first user plane function network element; and in a case where there is no user plane function network element belonging to the home network and other than the first user plane function network element in the visited place, or the other user plane function network element does not meet a set selection condition, selecting the second user plane function network element from a plurality of user plane function network elements belonging to the home network and deployed in the home place. In implementation, the selection condition used for selecting the H-UPF network element from the H-UPF network elements deployed in the home place can be the same as or different from the selection condition used for selecting the H-UPF network element from the H-UPF network elements deployed in the visited place.

[0066] In the second exemplary manner, the communication method can further include: in a case where there is, among the above-mentioned other user plane function network elements, a network element (which can be referred to as a third user plane function network element) that meets the selection condition, establishing, for the user equipment, a third HRPDU session via the third user plane function network element.

[0067] The updating of the locally stored session context information can be implemented in various exemplary manners. The following is described in conjunction with an exemplary manner.

[0068] In an exemplary manner, the updating of the locally stored session context information includes: updating Domain Name System (DNS) server information corresponding to the first HRPDU session to DNS server information corresponding to the second HRPDU session; and updating user plane path information corresponding to the first HRPDU session to user plane path information corresponding to the second HRPDU session.

[0069] The DNS server corresponding to the first HRPDU session is deployed in the visited place. The DNS server information corresponding to the first HRPDU session can be address information of the DNS server deployed in the visited place, or address information of an Edge Application Server Discovery Function (EASDF) deployed in the visited place.

[0070] The DNS server corresponding to the second HRPDU session is deployed in the home place. The DNS server information corresponding to the second HRPDU session can be address information of the DNS server deployed in the home place, or address information of an EASDF deployed in the home place.

[0071] In the embodiments of the present disclosure, by updating the DNS server information of the access place to the DNS server information of the home place, subsequent communication with the DNS server or the EASDF closer to the second user plane function network element is facilitated, and the transmission overhead of data in the roaming scenario is saved.

[0072] The user plane path information includes node information required to be passed through for transmitting data between the user equipment and the data network. For example, information of the UPF network element. In some examples, the first HR PDU session supports an uplink splitter function, and the uplink splitter function is implemented through the first user plane function network element. In these examples, updating the user plane path information can include: updating the uplink splitter information and the PDU session anchor point information corresponding to the first HR PDU session to the uplink splitter information and the PDU session anchor point information corresponding to the second HR PDU session.

[0073] In the embodiments of the present disclosure, on the one hand, by deploying the first user plane function network element in the home place in the visited place, data splitting through the first user plane function network element is enabled, and control and management (such as charging management, management of QoS flow, etc.) of the home place network on roaming data is enhanced. On the other hand, by designing the signaling flow shown in FIG. 1, continuity of roaming service can be ensured when the first user plane function network element fails.

[0074] FIG. 3 is a flow diagram of a communication method according to some embodiments of the present disclosure. As shown in FIG. 3, the communication method includes steps 301 to 304.

[0075] In step 301, a first HR PDU session is established.

[0076] In the embodiments of the present disclosure, a user equipment (UE) is located in a visited location, and a first HR PDU session is established through cooperation between network elements in a VPLMN and a HPLMN. The first HR PDU session is specifically a session between the user equipment and a data network via a V-UPF and a H-UPF (Remote H-UPF in FIG. 3) in the visited location in a home routed scenario. In some examples, establishing the first HR PDU session includes: the user equipment (UE) sending a first HR PDU session establishment request to an access and mobility management function (AMF) in a visited network through a radio access network (RAN); the AMF selecting an SMF supporting a home session breakout (HR-HSBO) mechanism in a home routed scenario, such as a V-SMF and a H-SMF in FIG. 3; the H-SMF selecting a UPF belonging to a home network and deployed in the visited location, such as a Remote H-UPF in FIG. 3; and the H-SMF establishing an N4 session with the Remote H-UPF.

[0077] The HR-HSBO mechanism can be understood as a mechanism of deploying a user plane function network element in a home network in a visited location and realizing roaming data shunting through the user plane function network element.

[0078] In specific implementation, the process of establishing the first HR PDU session includes the above steps and further includes the H-SMF sending a PDU session establishment response to the V-SMF, and signaling processes between the V-SMF and the AMF, between the AMF and the RAN, and between the RAN and the UE. The specific signaling processes can refer to related content about establishing a PDU session in a 3GPP standard.

[0079] In step 302, the Remote H-UPF sends a failure report to the H-SMF.

[0080] The failure report carries an identifier of the visited network, such as an identifier of the VPLMN. After receiving the failure report, the H-SMF can know which Remote H-UPF deployed in which visited location has failed according to the identifier of the visited network, so as to accurately perform H-UPF switching in the subsequent process, thereby maintaining the continuity of roaming services.

[0081] In step 303, the first HR PDU session is released.

[0082] In the embodiments of the present disclosure, the first HR PDU session is released through cooperation between network elements in a VPLMN and a HPLMN.

[0083] In some examples, the H-SMF manages the session of the user equipment in SSC mode2. In these examples, step 303 is performed before step 304.

[0084] For how step 303 is implemented in detail, refer to the foregoing related content.

[0085] In step 304, a second HR PDU session is established.

[0086] In embodiments of the present disclosure, the second HR PDU session is established through cooperation between network elements in the VPLMN and the HPLMN.

[0087] In some examples, establishing the second HR PDU session includes: the H-SMF selecting an H-UPF deployed in the home location; and the H-SMF instructing the H-UPF deployed in the home location (i.e., the H-UPF in FIG. 3) to establish a user plane connection. The H-SMF instructing the H-UPF deployed in the home location to establish the user plane connection can further include: the H-SMF sending an N4 session request to the H-UPF; and the H-UPF sending an N4 session response to the H-SMF.

[0088] In some examples, establishing the second HR PDU session further includes: updating locally stored session context information. For example, the H-SMF updates the locally stored session context information directly after receiving the N4 session response. For another example, the H-SMF updates the locally stored session context information after the H-UPF deployed in the home location sends a session update request to the H-SMF. For yet another example, the H-SMF updates the locally stored session context information after receiving a session update request from another network element (such as the V-SMF).

[0089] The H-SMF updating the locally stored session context information can include: the H-SMF updating DNS server information corresponding to the locally stored session, and updating user plane path information corresponding to the locally stored session. When the first HR PDU session supports the ULCL function, updating the user plane path information includes: updating ULCL node information and PSA node information corresponding to the session.

[0090] In addition, in specific implementation, the procedure of establishing the second HR PDU session can include a signaling procedure between the V-SMF and the AMF, a signaling procedure between the AMF and the RAN, a signaling procedure between the RAN and the UE, etc. in addition to the above steps. For specific signaling procedures, refer to related content about PDU session re-establishment in 3GPP standards.

[0091] In the embodiments of the present disclosure, the above process achieves support for the new HR-HSBO mechanism, and enhances the control and management of roaming data by the home network. In addition, by designing the signaling flow shown in FIG. 3, the continuity of roaming services can be ensured when the Remote H-UPF fails.

[0092] FIG. 4 is a structural schematic diagram of a communication apparatus according to some embodiments of the present disclosure. As shown in FIG. 4, the communication apparatus 400 includes an obtaining module 41, a session releasing module 42, and a session establishing module 43.

[0093] The obtaining module 41 is configured to obtain failure of a first user plane function network element in a home network. The first user plane function network element is deployed in a visited network.

[0094] The session releasing module 42 is configured to release a first HR PDU session established for a user equipment via the first user plane function network element. The user equipment is subscribed to the home network and located in the visited network.

[0095] The session establishing module 43 is configured to establish a second HR PDU session for the user equipment via a second user plane function network element in the home network. The second user plane function network element is deployed in the home network.

[0096] In the embodiments of the present disclosure, the above apparatus can achieve a new user plane function network element failure processing flow in a roaming scenario, and ensure the continuity of roaming services.

[0097] FIG. 5 is a structural schematic diagram of a communication apparatus according to some embodiments of the present disclosure. As shown in FIG. 5, the communication apparatus 50 is arranged in a session management function network element in a home network, and includes a memory 51 and a processor 52 coupled to the memory 51. The memory 51 is used to store instructions for executing corresponding embodiments of a communication method. The processor 52 is configured to execute the communication method in any of some embodiments of the present disclosure based on the instructions stored in the memory 51.

[0098] FIG. 6 is a structural schematic diagram of a communication system according to some embodiments of the present disclosure. As shown in FIG. 6, the communication system 60 includes a SMF network element 61 in a home network, a first UPF network element 62 in the home network, and a second UPF network element 63 in the home network. The first UPF network element 62 is deployed in a visited network, and the second UPF network element 63 is deployed in a home network.

[0099] The SMF network element 61 is configured to establish a first HR PDU session via the first UPF network element for a user equipment roaming to a visited network.

[0100] The SMF network element 61 is further configured to release the first HR PDU session and establish a second HR PDU session for the user equipment via the second UPF network element 63 after determining that the first UPF network element 62 fails.

[0101] For how the SMF network element specifically releases the first HR PDU session and establishes the second HR PDU session, reference can be made to the foregoing relevant description.

[0102] The first UPF network element 62 is configured to assist the SMF network element 61 in releasing the first HR PDU session.

[0103] The second UPF network element 63 is configured to assist the SMF network element 61 in establishing the second HR PDU session.

[0104] In the embodiments of the present disclosure, through the cooperation of various devices in the communication system, the communication method as described above is realized. Through the above system, the control and management of roaming data by the home network can be enhanced, and the continuity of roaming services when the first UPF network element fails can be ensured.

[0105] Here, various aspects of the present disclosure are described with reference to flowcharts and / or block diagrams of the methods, apparatuses and computer program products according to the embodiments of the present disclosure. It should be understood that each block of the flowcharts and / or block diagrams, and combinations of the blocks, can be implemented by computer readable program instructions.

[0106] These computer readable program instructions can be provided to a processor of a general purpose computer, a special purpose computer, or other programmable data processing apparatus to produce a machine, so that the instructions executed by the processor generate the apparatus that implements the functions specified in one or more blocks of the flowcharts and / or block diagrams.

[0107] These computer readable program instructions can also be stored in a computer readable storage medium that causes a computer to operate in a specific manner, thereby producing an article of manufacture including instructions that implement the functions specified in one or more blocks of the flowcharts and / or block diagrams.

[0108] The present disclosure can take the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment combining software and hardware aspects.

[0109] So far, the communication method, apparatus and system according to the present disclosure have been described in detail. In order to avoid obscuring the concept of the present disclosure, some details known in the art are not described. Those skilled in the art can fully understand how to implement the technical solutions disclosed herein according to the above description.

Claims

1. A communication method, performed by a session management function network element in a home network, comprising: learning a failure of a first user plane function network element in the home network, wherein the first user plane function network element is deployed in a visited network; releasing a first home routed protocol data unit, HR PDU, session established for a user equipment via the first user plane function network element; establishing a second HR PDU session for the user equipment via a second user plane function network element in the home network, wherein the second user plane function network element is deployed in the home network.

2. The communication method according to claim 1, wherein, the establishing the second HR PDU session via the second user plane function network element in the home network comprises: selecting the second user plane function network element; sending a session request to the second user plane function network element; receiving a session response from the second user plane function network element.

3. The communication method according to claim 2, wherein, the establishing the second HR PDU session via the second user plane function network element in the home network further comprises: updating locally stored session context information.

4. The communication method according to claim 3, wherein the updating locally stored session context information comprises: updating information of a domain name system, DNS, server corresponding to a first HR PDU session to information of a DNS server corresponding to a second HR PDU session, wherein the DNS server corresponding to the first HR PDU session is deployed in the visited network, and the DNS server corresponding to the second HR PDU session is deployed in the home network; and / or updating user plane path information corresponding to the first HR PDU session to user plane path information corresponding to the second HR PDU session.

5. The communication method according to claim 2, wherein, the selecting the second user plane function network element comprises: in a case that there is no other user plane function network element belonging to the home network except the first user plane function network element in the visited network, or in a case that there is the other user plane function network element in the visited network but the other user plane function network element does not satisfy a set selection condition, selecting the second user plane function network element from user plane function network elements belonging to the home network and deployed in the home network. 6.The communication method of claim 5, further comprising: in a case that there is a network element satisfying the selection condition among the other user plane function network elements, establishing a third HR PDU session for the user equipment via the network element satisfying the selection condition.

7. The communication method according to claim 4, wherein, the updating the user plane path information corresponding to the first HR PDU session to the user plane path information corresponding to the second HR PDU session comprises: updating uplink splitter information and PDU session anchor point information corresponding to the first HR PDU session to uplink splitter information and PDU session anchor point information corresponding to the second HR PDU session.

8. The communication method according to any one of claims 1 to 7, wherein the first user plane function network element supports uplink splitter function and PDU session anchor point function established for the first HR PDU session.

9. The communication method according to any one of claims 1 to 7, wherein the learning the failure of the first user plane function network element in the home network comprises: receiving a failure report from the first user plane function network element; determining the failure of the first user plane function network element according to the failure report. 10.The communication method of claim 9, wherein the failure report carries an identity of a visited network. 11.A communication apparatus configured to be deployed in a session management function network element in a home network, comprising: an obtaining module configured to obtain a failure of a first user plane function network element in the home network, wherein the first user plane function network element is deployed in a visited network; a session releasing module configured to release a first home routed protocol data unit (HR-PDU) session established for a user equipment via the first user plane function network element; a session establishing module configured to establish a second HR-PDU session for the user equipment via a second user plane function network element in the home network, wherein the second user plane function network element is deployed in the home network. 12.A communication apparatus comprising: a memory; and a processor coupled to the memory and configured to execute a communication method according to any one of claims 1 to 10 based on instructions stored in the memory. 13.A communication system comprising: a session management function network element in a home network, comprising a communication apparatus according to claim 11 or 12; the first user plane function network element configured to assist the session management function network element to release a first HR-PDU session; and the second user plane function network element configured to assist the session management function network element to establish a second HR-PDU session. 14.A computer readable storage medium having computer program instructions stored thereon, the instructions being executable by a processor to implement a communication method according to any one of claims 1 to 10. 15.A computer program product having computer program instructions stored thereon, the instructions being executable by a processor to implement a communication method according to any one of claims 1 to 10. ​

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