A service switching method, apparatus and network device

Abstract

An embodiment of the present invention provides a service switching method, apparatus and network device. The method applied to the SMF includes: when detecting that a first user plane function network element UPF carrying the current service fails, sending first indication information to a policy control function network element PCF, where the first indication information is used to indicate that the N4 link between the SMF and the first user plane function network element UPF is disconnected, and to indicate the PCF to modify the status value of the pre-recorded N4 link; receiving the modified status value of the N4 link and the pre-recorded UPF priority value sent by the PCF, where the UPF priority value is used to indicate the UPF carrying the current service; and switching the service carried by the first user plane function network element UPF to a second UPF according to the modified status value of the N4 link and the pre-recorded UPF priority value. Therefore, the embodiment of the present invention can automatically switch the UPF carrying the service, so as to quickly restore the user-interrupted service.

Description

Technical Field

[0001] The present invention relates to the field of mobile communication technologies, and in particular, to a service handover method, apparatus, and network device. Background Art

[0002] Currently, the construction of the fifth-generation mobile communication technology (5G) network has entered the fast lane. Under the background of the construction of new infrastructure (referred to as new infrastructure for short), the demand for digital transformation through 5G technology is more urgent. Among them, due to the obvious differences in the informatization characteristics of different industries and the varying degrees of informatization requirements in inter-industry business scenarios, some enterprises hope to obtain full control of the 5G network and require the 5G network to have high reliability, security, privacy, etc. Therefore, the current public network can no longer fully meet these specific needs.

[0003] Therefore, it is an inevitable measure to deploy a 5G private network for industries. Currently, a converged and collaborative 5G private network solution of "network customization, edge intelligence, cloud collaboration, and X on-demand" has been proposed, aiming to create an integrated and customized service for customers and achieve the goal of "cloud-network integration and on-demand customization". Among them, "network customization" provides three types of network solutions, namely "slice", "edge", and "independent", for the differentiated requirements of industry customers for the coverage range of the 5G network, the security isolation level requirements, the depth of air interface customization, etc., and matches the corresponding networking scenarios, such as "distant", "adjacent", and "wing-like". These three networking scenarios connect the user port function (UPF) network element in the 5G standalone (SA) and the autonomous system boundary router (ASBR) / B device in the fixed network routing device, and achieve the purpose of 5G terminals accessing the enterprise production intranet through the government-enterprise dedicated line.

[0004] Among them, after the customized private network user terminal accesses the UPF through the 5G base station, the enterprise data is transmitted through the intelligent transport network (STN) dedicated line method by the ASBR / B device. Currently, the 5G base station can poll and access the control plane network elements of the 5G core network (5GC), and these control plane network elements all have redundant protection. Specifically, the control plane network element selects a single UPF to carry the service, and a dual-link protection is deployed between the UPF and the ASBR / B device, that is, a primary and standby pseudowire (PW) channel is deployed with dual ASBR / dual B devices on the dedicated line side to reach the U device on the enterprise intranet side.

[0005] Among them, if the UPF network element carrying the service has a device-level failure, even if a standby UPF network element is deployed, the Session Management Function (SMF) network element cannot automatically reselect to the standby UPF network element. In this case, maintenance personnel need to intervene, and only by manually deleting the faulty UPF configuration can the service be restored 100%. In this way, the services of enterprise customers will be interrupted for a period of time, causing certain losses to the actual production of customers.

[0006] As can be seen from the above, in the prior art, when the UPF network element carrying the service has a device-level failure, only by manually deleting the faulty UPF configuration can the service be restored, resulting in a long service interruption time. Summary of the Invention

[0007] Embodiments of the present invention provide a service switching method, device, and network device to solve the problem in the prior art that when the UPF network element carrying the service has a device-level failure, only by manually deleting the faulty UPF configuration can the service be restored, resulting in a long service interruption time.

[0008] In a first aspect, an embodiment of the present invention provides a service switching method applied to a Session Management Function (SMF) network element. The method includes:

[0009] When detecting that the first User Plane Function (UPF) network element currently carrying the service has a failure, send a first indication message to a Policy Control Function (PCF) network element, where the first indication message is used to indicate that the N4 link between the SMF and the first User Plane Function (UPF) network element is disconnected, and to indicate the PCF to modify the status value of the pre-recorded N4 link;

[0010] Receive the modified status value of the N4 link and the pre-recorded UPF priority value sent by the PCF, where the UPF priority value is used to indicate the UPF currently carrying the service;

[0011] According to the modified status value of the N4 link and the pre-recorded UPF priority value, switch the service carried by the first User Plane Function (UPF) network element to a second UPF.

[0012] In a second aspect, an embodiment of the present invention further provides a service switching method applied to a Policy Control Function (PCF) network element. The method includes:

[0013] Receive the first indication message sent by the Session Management Function (SMF) network element when the first User Plane Function (UPF) network element currently carrying the service has a failure, where the first indication message is used to indicate that the N4 link between the SMF and the first User Plane Function (UPF) network element is disconnected;

[0014] Modify the status value of the pre-recorded N4 link according to the first indication information;

[0015] Send the modified status value of the N4 link and the pre-recorded UPF priority value to the SMF, so that the SMF switches the service carried by the first user plane function network element UPF to the second UPF according to the modified status value of the N4 link and the pre-recorded UPF priority value, where the UPF priority value is used to indicate the UPF currently carrying the service.

[0016] In a third aspect, an embodiment of the present invention provides a service switching device, which is applied to a session management function network element SMF. The device includes:

[0017] A first sending module, configured to send first indication information to a policy control function network element PCF when it is detected that a first user plane function network element UPF currently carrying a service fails, where the first indication information is used to indicate that the N4 link between the SMF and the first user plane function network element UPF is disconnected, and to indicate the PCF to modify the status value of the pre-recorded N4 link;

[0018] A first receiving module, configured to receive the modified status value of the N4 link and the pre-recorded UPF priority value sent by the PCF, where the UPF priority value is used to indicate the UPF currently carrying the service;

[0019] A first switching module, configured to switch the service carried by the first user plane function network element UPF to the second UPF according to the modified status value of the N4 link and the pre-recorded UPF priority value.

[0020] In a fourth aspect, an embodiment of the present invention provides a service switching device, which is applied to a policy control function network element PCF. The device includes:

[0021] A second receiving module, configured to receive first indication information sent by a session management function network element SMF when a first user plane function network element UPF currently carrying a service fails, where the first indication information is used to indicate that the N4 link between the SMF and the first user plane function network element UPF is disconnected;

[0022] A first modification module, configured to modify the status value of the pre-recorded N4 link according to the first indication information;

[0023] A second sending module, configured to send the modified status value of the N4 link and a pre-recorded UPF priority value to the SMF, so that the SMF switches the services borne by the first user plane function network element UPF to the second UPF according to the modified status value of the N4 link and the pre-recorded UPF priority value, where the UPF priority value is used to indicate the UPF currently bearing services.

[0024] In a fifth aspect, an embodiment of the present invention provides a network device, including a memory, a transceiver, and a processor:

[0025] The memory is configured to store a computer program; the transceiver is configured to send and receive data under the control of the processor; the processor is configured to read the computer program in the memory and execute the service switching method described in the first aspect above, or the service switching method described in the second aspect above.

[0026] In a sixth aspect, an embodiment of the present invention provides a processor-readable storage medium, where the processor-readable storage medium stores a computer program, and the computer program is used to cause the processor to execute the service switching method described in the first aspect above, or execute the service switching method described in the second aspect above.

[0027] In an embodiment of the present invention, when the SMF detects that the first UPF currently bearing services fails, the SMF can send first indication information indicating that the N4 link between the SMF and the first UPF is disconnected to the PCF, so that the PCF modifies the status value of the N4 link according to the first indication information, and then sends the modified status value of the N4 link and a pre-stored UPF priority value used to indicate the UPF currently bearing services to the SMF, so that the SMF switches the services borne by the first UPF to the second UPF according to the modified status value of the N4 link and the UPF priority value.

[0028] It can be seen that the embodiment of the present invention provides a dual-UPF networking, and when one of the UPF devices fails, the services can be automatically switched to another UPF. On the one hand, it can liberate the human resource investment of maintenance personnel, and on the other hand, it can quickly restore the services interrupted by users, greatly reducing the degree of loss of customer interests. Description of the Drawings

[0029] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for the description of the embodiments of the present invention will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0030] Figure 1 It is a dual-UPF networking architecture diagram of a 5G SA customized private network in the prior art;

[0031] Figure 2 It is one of the flowcharts of the service switching method provided by the embodiments of the present invention;

[0032] Figure 3 It is the second flowchart of the service switching method provided by the embodiments of the present invention;

[0033] Figure 4 It is one of the flowcharts of the specific implementation manner of the service switching method according to the embodiments of the present invention;

[0034] Figure 5 It is the second flowchart of the specific implementation manner of the service switching method according to the embodiments of the present invention;

[0035] Figure 6 It is one of the structural block diagrams of the service switching device provided by the embodiments of the present invention;

[0036] Figure 7 It is the second structural block diagram of the service switching device provided by the embodiments of the present invention;

[0037] Figure 8 It is the structural block diagram of the network device provided by the embodiments of the present invention. Specific implementation manner

[0038] In the embodiments of the present invention, the term "and / or" describes the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B may represent: A exists alone, A and B exist simultaneously, and B exists alone. The character " / " generally represents an "or" relationship between the associated objects before and after.

[0039] In the embodiments of the present application, the term "a plurality of" refers to two or more, and other quantifiers are similar.

[0040] Next, the technical solutions in the embodiments of the present application will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present application.

[0041] The embodiments of the present application provide a service switching method and device to solve the problem in the prior art that when a UPF network element carrying services fails at the device level, the fault UPF configuration can only be manually deleted, resulting in a long service interruption time.

[0042] Among them, the method and the apparatus are based on the same inventive concept. Since the principles of problem-solving of the method and the apparatus are similar, the implementation of the apparatus and the method can be referred to each other, and the repeated parts will not be elaborated.

[0043] To facilitate the understanding of the service switching method of the embodiments of the present invention, the following content is first introduced:

[0044] Currently, the dual-UPF networking mode of 5G SA customized private networks is as Figure 1 shown. That is, for the high-bandwidth, low-latency, and secure access requirements of industrial customers, the 5G customized private network isolates different enterprise services through the customized data network name (DNN) + STN dedicated line method, and provides proprietary access services for enterprise customers.

[0045] Among them, the implementation method of 5G customized private network services is as follows: The 5G terminal sets the customized DNN and SA mode, and after searching for the 5G base station (gNB) signal, it accesses the 5GC control plane from the gNB through the IP radio access network (IPRAN) bearer network. The SMF selects a user plane network element UPF1 (primary) to allocate the private IP address of the enterprise to the terminal (i.e., the customer premise equipment (CPE)). According to the obtained private IP address, the CPE sends the service data to the core network UPF1 through the gNB, and then the service data is transmitted to the enterprise intranet through the STN dedicated line.

[0046] It can be seen that in the process of the CPE accessing the intranet, the devices and network elements passed through include the gNB, IPRAN routing devices, UPF, and STN dedicated line devices, and dual or multiple devices and network elements are deployed for redundant disaster tolerance protection.

[0047] Among them, when the device carrying the service among the gNB, IPRAN routing device, and STN dedicated line device fails, the service can be automatically migrated to the standby device through the standby route. However, if a device-level failure occurs in the UPF, due to the existing mechanism of the SMF selecting the UPF according to the TAC, DNN, and slice, the SMF cannot select the standby UPF, and the terminal will also send an IP address allocation request anchored to the faulty UPF after going offline, resulting in a continuous interruption problem of the service, and maintenance personnel need to intervene to manually adjust and migrate the service to the standby UPF.

[0048] In addition, it should be noted that Figure 1 the vlan in it is the virtual local area network, the NSSF is the network slice selection function entity, the NRF is the network function entity storage function network element, the NEF is the network extension function network element, the AUSF is the authentication server function network element, and the Naf is the network application function network element.

[0049] Figure 2 The flowchart shows a service switching method provided by an embodiment of the present invention. This service switching method can be applied to the SMF, such as Figure 2 shown, and the method may include the following steps:

[0050] Step 201: When it is detected that the first user plane function network element UPF carrying the current service fails, send a first indication message to the policy control function network element PCF.

[0051] In the embodiment of the present invention, the SMF is connected to the first UPF through an N4 link, and the SMF is connected to the second UPF through another N4 link. Therefore, when any one of the first UPF and the second UPF fails, the N4 link between the failed UPF and the SMF will be disconnected, and the SMF can detect the status of the N4 link in real time. Therefore, the SMF can detect whether the first UPF and the second UPF fail.

[0052] Wherein, the above first indication message is used to indicate that the N4 link between the SMF and the first user plane function network element UPF is disconnected, and to indicate the PCF to modify the previously recorded status value of the N4 link.

[0053] In addition, the status value of the N4 link recorded in the PCF is used to indicate the status of the N4 link between the UPF carrying the current service and the SMF. When the PCF receives the above first indication message from the SMF and learns that the N4 link between the first UPF carrying the current service and the SMF is disconnected, it is necessary to modify the locally recorded N4 link status value to a value used to represent that the N4 link between the first UPF and the SMF is disconnected.

[0054] Step 202: Receive the modified status value of the N4 link and the previously recorded UPF priority value sent by the PCF.

[0055] Wherein, the UPF priority value is used to indicate the UPF carrying the current service. That is, in the PCF, there is also a UPF priority value used to indicate which UPF is the UPF carrying the current service. For example, when the PCF receives the above first indication message and the UPF carrying the service is still the first UPF, the UPF priority value recorded in the PCF indicates that the UPF carrying the current service is the first UPF.

[0056] Step 203: According to the modified status value of the N4 link and the previously recorded UPF priority value, switch the service carried by the first user plane function network element UPF to the second UPF.

[0057] In an embodiment of the present invention, in step 203, the status value of the N4 link received by the SMF indicates that the N4 link between the SMF and the first UPF is disconnected, and the received UPF priority value indicates that the UPF currently carrying the service is the first UPF. Therefore, the SMF needs to switch the service carried on the first UPF to the second UPF to shorten the service interruption time.

[0058] As can be seen from the above steps 201 to 203, in the embodiment of the present invention, when the SMF detects that the first UPF currently carrying the service fails, the SMF can send the first indication information for indicating that the N4 link between the SMF and the first UPF is disconnected to the PCF, so that the PCF modifies the status value of the N4 link according to the first indication information, and then sends the modified status value of the N4 link and the pre-stored UPF priority value for indicating the UPF currently carrying the service to the SMF, so that the SMF switches the service carried on the first UPF to the second UPF according to the modified status value of the N4 link and the UPF priority value.

[0059] It can be seen that the embodiment of the present invention provides a dual-UPF networking, and when one of the UPF devices fails, the service can be automatically switched to the other UPF. On the one hand, it can liberate the human resource investment of maintenance personnel, and on the other hand, it can quickly restore the service interrupted by users, greatly reducing the degree of loss of customer interests.

[0060] Optionally, the first indication information includes the status value of the N4 link with a first preset value, and the first preset value is used to indicate that the N4 link between the SMF and the first user plane function network element UPF is disconnected;

[0061] Sending the first indication information to the PCF includes:

[0062] Sending a first request message for deleting the session of the first terminal device UE to the PCF, where the first terminal device UE is one of the UEs to which the service carried on the first user plane function network element UPF belongs, and the first request message carries the status value of the N4 link with the first preset value.

[0063] It can be seen that when the first UPF currently carrying the service fails, causing the N4 link between the first UPF and the SMF to be disconnected, all UEs on the first UPF can be deactivated. Therefore, for one of the UEs to which the service carried on the first UPF belongs, the SMF can send a session deletion request message for this UE to the PCF, and carry the status value of the N4 link with the first preset value in the session deletion request message to inform the PCF that the N4 link between the first UPF currently carrying the service and the SMF is disconnected.

[0064] In addition, it should be noted that when deactivating all UEs on the first UPF, the SMF can send a delete session request message to the PCF for each UE respectively, and the status value of the N4 link with a value of the first preset value is carried in these delete session request messages.

[0065] In addition, the status value of the N4 link recorded in the PCF can also be UE-corresponding. That is, in the PCF, a status value of an N4 link is recorded for one UE. In this way, when the PCF receives a delete session request message, it deletes the session of the UE corresponding to the request message and modifies the status value of the N4 link corresponding to the UE to a value indicating that the N4 link between the first UPF carrying the current service and the SMF is disconnected.

[0066] Similarly, the UPF priority value recorded in the PCF can also be UE-corresponding. That is, in the PCF, a UPF priority value is recorded for one UE.

[0067] Optionally, receiving the modified status value of the N4 link and the pre-recorded UPF priority value sent by the PCF includes:

[0068] After the first user equipment (UE) is re-connected to the network, sending a first policy control request message to the PCF;

[0069] Receiving the first policy and charging control rule sent by the PCF, where the first policy and charging control rule includes the status value of the N4 link with a value of the first preset value and the UPF priority value with a value of the second preset value, and the second preset value is used to indicate that the UPF carrying the current service is the first user plane function network element UPF.

[0070] Among them, the reconnection of the first UE to the network means that the UE re-initiates the session establishment process, that is, the first UE re-sends a protocol data unit (PDU) session establishment request to the Access and Mobility Management Function (AMF) network element, so that the AMF sends the PDU session establishment request to the SMF. In this way, the SMF can know that the first UE is re-connected to the network, and thus send the above first policy control request message to the PCF.

[0071] In addition, the foregoing first indication information received by the PCF includes the status value of the N4 link with a value of the first preset value. Therefore, the status value of the N4 link modified by the PCF is the first preset value; the foregoing pre-recorded UPF priority value indicates that the UPF carrying the current service is the first UPF. Therefore, the pre-recorded UPF priority value is the second preset value.

[0072] As can be seen from the above, the status value of the N4 link with a value of the first preset value and the UPF priority value with a value of the second preset value can be carried by the PCF in the PCC rule and returned to the SMF during the process of the SMF requesting the Policy and Charging Control Rule (PCC Rule) from the PCF.

[0073] Optionally, according to the modified status value of the N4 link and the pre-recorded UPF priority value, the process of switching the service of the first terminal device UE carried by the first user plane function network element UPF to the second UPF includes:

[0074] Perform an operation on the first preset value and the second preset value according to a preset operation rule to obtain a first operation result;

[0075] According to the first operation result, switch the service of the first terminal device UE carried by the first user plane function network element UPF to the second UPF.

[0076] It can be seen that in the embodiments of the present invention, an operation can be performed on the specific value of the status value of the N4 link and the specific value of the UPF priority value according to a preset operation rule, so as to switch the service of the first UE carried by the first UPF to the second UPF according to the obtained first operation result.

[0077] Among them, the foregoing first operation result represents the priority value of the UPF to be switched. And, in the embodiments of the present invention, different UPFs have their respective priority values. Therefore, the UPF whose priority value is the same as the first operation result is the UPF to be switched.

[0078] For example, when the status value of the N4 link takes the value of 1, it indicates that the link between the UPF currently carrying the service and the SMF is disconnected, and when it is 0, it indicates that the link is not disconnected; when the UPF priority value takes the value of 0, it indicates that the UPF currently carrying the service is the first UPF, and when it is 1, it indicates that the UPF currently carrying the service is the second UPF; if the priority value of the first UPF is 0 and the priority value of the second UPF is 1, then the aforementioned first preset value is 0 and the second preset value is 1. Then, if the preset operation rule is "exclusive OR", the exclusive OR result of 0 and 1 is "1", which means that the service needs to be switched to the UPF with a priority value of "1", that is, the second UPF.

[0079] Optionally, the step of switching the service of the first terminal device UE carried by the first user plane function network element UPF to the second UPF according to the first operation result includes:

[0080] Obtain the tracking area identifier of the cell where the first terminal device UE is located, the data network name of the network where the first terminal device UE is located, and the first network slice;

[0081] Select a UPF group associated with the tracking area identifier, the data network name, and the first network slice, where a UPF group includes two UPFs with different priority values;

[0082] Determine the UPF with a priority value the same as the first operation result in the selected group of UPFs as the second UPF;

[0083] Switch the service of the first terminal device UE carried by the first user plane function network element UPF to the second UPF.

[0084] Among them, in the network architecture applicable to the embodiments of the present invention (such as the 5G network architecture), there are multiple groups of UPFs. According to the tracking area identifier (Tracking Area Identity, TAC), data network name (Data Network Name, DNN) of the cell where the first UE is located, and the first network slice, a group of UPFs can be located. Then, among this group of UPFs, the UPF with a priority value the same as the above first operation result can be selected as the UPF to which the service is to be switched.

[0085] Optionally, after switching the service carried by the first user plane function network element UPF to the second UPF, the method further includes:

[0086] When the second UE needs to go offline and the second UPF has not failed, send second indication information to the PCF, where the second indication information is used to indicate that the N4 link between the SMF and the first user plane function network element UPF is not disconnected, and to indicate that the PCF modifies the status value of the N4 link and the UPF priority value;

[0087] Wherein, the second UE is one of the UEs to which the services carried on the second UPF belong.

[0088] It should be noted here that the above "the second UE needs to go offline" is the normal offline process of the second UE, rather than being triggered by a UPF failure.

[0089] As can be seen from the above, after the services carried by the first UPF are switched to the second UPF, if one of the UEs on the second UPF needs to go offline normally and the second UPF has not failed at this time (that is, the N4 link between the second UPF and the SMF is not disconnected at this time), the SMF can send the above second indication information to the PCF so that the PCF modifies the status value of the N4 link and the UPF priority value.

[0090] Wherein, when the PCF receives the second indication information, the N4 link between the second UPF and the SMF is not disconnected, and the UPF currently carrying the service is the second UPF. Therefore, after the PCF receives the second indication information, it needs to modify the status value of the N4 link to a value indicating that the N4 link between the second UPF and the SMF is not disconnected, and modify the UPF priority value to a value indicating that the UPF currently carrying the service is the second UPF.

[0091] That is, as can be seen from the above content, when a UE needs to go offline (including normal offline and offline triggered by the failure of the UPF currently carrying the service), the PCF modifies the status value of the N4 link according to the indication information sent by the SMF received by it, which is used to indicate the actual status of the N4 link between the UPF currently carrying the service and the SMF; while the PCF only modifies the UPF priority value when the UE goes offline normally.

[0092] Optionally, the second indication information includes the status value of the N4 link with a third preset value, and the third preset value is used to indicate that the N4 link between the SMF and the second UPF is not disconnected;

[0093] The sending the second indication information to the PCF includes:

[0094] Send a second request message to the PCF to delete the session of the second UE, where the second request message carries the status value of the N4 link with the third preset value.

[0095] It can be seen from this that when the second UE is normally offline from the second UPF, if the second UPF does not fail, that is, the N4 link between the second UPF and the SMF is not broken, the SMF can deactivate the second UE, that is, the SMF can send a delete session request message for the second UE to the PCF, and carry the status value of the N4 link with a value of the third preset value in the delete session request message to inform the PCF that the N4 link between the second UPF carrying the current service and the SMF is not disconnected.

[0096] Optionally, after sending the second indication information to the PCF, the method further includes:

[0097] After the second UE is back online, receiving the status value of the N4 link and the UPF priority value modified most recently sent by the PCF;

[0098] Setting the second UPF to carry the service of the second UE according to the status value of the N4 link and the UPF priority value modified most recently.

[0099] It can be seen from this that if, after the second UE is normally offline from the second UPF, it needs to be back online again, the SMF can obtain the status value of the N4 link and the UPF priority value modified most recently by the PCF from the PCF, and thus set the second UPF to carry the service of the second UE according to the status value of the N4 link and the UPF priority value modified most recently by the PCF.

[0100] Optionally, the receiving the status value of the N4 link and the UPF priority value modified most recently sent by the PCF includes:

[0101] Sending a second policy control request message to the PCF;

[0102] Receiving the second policy and charging control rule sent by the PCF, where the second policy and charging control rule includes the status value of the N4 link with a value of the third preset value and the UPF priority value with a value of the fourth preset value, the third preset value is used to indicate that the N4 link between the SMF and the second UPF is not disconnected, and the fourth preset value is used to indicate that the UPF carrying the current service is the second UPF.

[0103] Wherein, the status value of the N4 link modified most recently by the PCF is the third preset value, and the UPF priority value modified most recently is the fourth preset value.

[0104] It can be seen therefrom that the status value of the N4 link with the third preset value and the UPF priority value with the fourth preset value can be carried by the PCF in the PCC rule and returned to the SMF during the process of the SMF requesting the PCC rule from the PCF.

[0105] Optionally, the setting the second UPF to carry the service of the second UE according to the status value of the N4 link modified most recently and the UPF priority value includes:

[0106] Performing an operation on the third preset value and the fourth preset value according to a preset operation rule to obtain a second operation result;

[0107] Setting the second UPF to carry the service of the second UE according to the second operation result.

[0108] It can be seen therefrom that in the embodiments of the present invention, an operation can be performed on the specific value of the status value of the N4 link and the specific value of the UPF priority value according to a preset operation rule, so as to set the second UPF to carry the service of the second UE according to the second operation result.

[0109] Wherein, the above-mentioned second operation result represents the priority value of the UPF to carry the service of the second UE. And, in the embodiments of the present invention, different UPFs have their respective priority values. Therefore, if the second operation result is the same as the priority value of a certain UPF, that UPF is the UPF to carry the service of the second UE.

[0110] For example, when the status value of the N4 link takes the value of 1, it means that the link between the current service-carrying UPF and the SMF is disconnected, and when it is 0, it means it is not disconnected; when the UPF priority value takes the value of 0, it means that the current service-carrying UPF is the first UPF, and when it is 1, it means that the current service-carrying UPF is the second UPF; the priority value of the first UPF is 0, and the priority value of the second UPF is 1; then the aforementioned third preset value is 0 and the fourth preset value is 1. Then, if the preset operation rule is "exclusive OR", the exclusive OR result of 0 and 1 is "1", which means that the UPF to carry the service of the second UE is the UPF with the priority value of "1", that is, the second UPF.

[0111] Optionally, the setting the second UPF to carry the service of the second UE according to the second operation result includes:

[0112] Obtaining the tracking area identifier of the cell where the second UE is located, the data network name of the network where the second UE is located, and the second network slice;

[0113] Select a UPF packet associated with the tracking area identity of the cell where the second UE is located, the data network name of the network where the second UE is located, and the second network slice. One UPF packet includes two UPFs with different priority values.

[0114] Among the selected group of UPFs, the UPF with a priority value the same as the first operation result is determined as the second UPF.

[0115] Configure the second UPF to carry the services of the second UE.

[0116] Wherein, in the network architecture applicable to the embodiments of the present invention (such as the 5G network architecture), there are multiple groups of UPFs. Therefore, according to the TAC of the cell where the second UE is located, the DNN of the network where it is located, and the second network slice, a group of UPFs can be located. Then, among this group of UPFs, the UPF with a priority value the same as the above second operation result can be selected as the UPF to carry the services of the second UE.

[0117] Figure 3 The flowchart of a service handover method provided by an embodiment of the present invention is shown. This service handover method can be applied to a PCF, as Figure 3 shown, and this method may include the following steps:

[0118] Step 301: Receive first indication information sent by a session management function network element SMF when a first user plane function network element UPF that is currently carrying services fails.

[0119] In the embodiments of the present invention, the SMF is connected to the first UPF through an N4 link, and the SMF is connected to the second UPF through another N4 link. Therefore, when any one of the first UPF and the second UPF fails, the N4 link between the failed UPF and the SMF will be disconnected, and the SMF can detect the status of the N4 link in real time. Therefore, the SMF can detect whether the first UPF and the second UPF have failed.

[0120] Step 302: Modify the pre-recorded status value of the N4 link according to the first indication information.

[0121] Wherein, the first indication information is used to indicate that the N4 link between the SMF and the first user plane function network element UPF is disconnected.

[0122] In addition, the status value of the N4 link recorded in the PCF is used to indicate the status of the N4 link between the UPF currently carrying the service and the SMF. When the PCF receives the above-mentioned first indication information sent by the SMF and learns that the N4 link between the first UPF currently carrying the service and the SMF is disconnected, it is necessary to modify the status value of the N4 link recorded locally to a value indicating that the N4 link between the first UPF and the SMF is disconnected.

[0123] Step 303: Send the modified status value of the N4 link and the pre-recorded UPF priority value to the SMF, so that the SMF can switch the service carried by the first user plane function network element UPF to the second UPF according to the modified status value of the N4 link and the pre-recorded UPF priority value.

[0124] Among them, the UPF priority value is used to indicate the UPF currently carrying the service. That is, in the PCF, there is also a UPF priority value used to indicate which UPF is the UPF currently carrying the service. For example, when the PCF receives the above-mentioned first indication information, if the UPF carrying the service is still the first UPF, the UPF priority value recorded in the PCF indicates that the UPF currently carrying the service is the first UPF.

[0125] In addition, in step 303, the status value of the N4 link sent by the PCF to the SMF indicates that the N4 link between the SMF and the first UPF is disconnected, and the UPF priority value sent to the SMF indicates that the UPF currently carrying the service is the first UPF. Therefore, after the SMF receives the status value of the N4 link and the UPF priority value, it is necessary to switch the service carried on the first UPF to the second UPF to shorten the service interruption time.

[0126] It can be seen from the above steps 301 to 303 that in the embodiment of the present invention, when the SMF detects that the first UPF currently carrying the service fails, it can send the first indication information indicating that the N4 link between the SMF and the first UPF is disconnected to the PCF, so that the PCF can modify the status value of the N4 link according to the first indication information, and then send the modified status value of the N4 link and the pre-stored UPF priority value used to indicate the UPF currently carrying the service to the SMF, so that the SMF can switch the service carried by the first UPF to the second UPF according to the modified status value of the N4 link and the UPF priority value.

[0127] It can be seen that the embodiment of the present invention provides a dual-UPF networking, and when one of the UPF devices fails, the service can be automatically switched to another UPF. On the one hand, it can liberate the human resource investment of maintenance personnel, and on the other hand, it can quickly restore the service interrupted by users, greatly reducing the degree of loss of customer interests.

[0128] Optionally, the first indication information includes a status value of the N4 link with a first preset value, where the first preset value is used to indicate that the N4 link between the SMF and the first user plane function network element UPF is disconnected;

[0129] The process of receiving the first indication information includes:

[0130] Receiving a first request message for deleting a session of a first terminal device UE sent by the SMF, where the first terminal device UE is one of the UEs to which the services carried on the first user plane function network element UPF belong, and the status value of the N4 link with the first preset value is carried in the first request message.

[0131] Optionally, after receiving the first request message for deleting a session of the first terminal device UE sent by the SMF, the method further includes:

[0132] Deleting the session of the first terminal device UE.

[0133] It can be seen that when a failure occurs in the first UPF that currently bears services, causing the N4 link between the first UPF and the SMF to be disconnected, all UEs on the first UPF can be deactivated. Therefore, for one of the UEs to which the services carried on the first UPF belong, the SMF can send a session deletion request message for this UE to the PCF, and carry the status value of the N4 link with the first preset value in the session deletion request message to inform the PCF that the N4 link between the first UPF that currently bears services and the SMF is disconnected.

[0134] In addition, it should be noted that when deactivating all UEs on the first UPF, the SMF can send a session deletion request message to the PCF for each UE respectively, and the status value of the N4 link with the first preset value is carried in these session deletion request messages.

[0135] In addition, the status value of the N4 link recorded in the PCF can also be UE-corresponding. That is, one UE records one status value of the N4 link in the PCF. In this way, when the PCF receives a session deletion request message, it deletes the session of the UE corresponding to the request message and modifies the status value of the N4 link corresponding to this UE to: the value used to indicate that the N4 link between the first UPF that currently bears services and the SMF is disconnected.

[0136] Similarly, the UPF priority value recorded in the PCF can also be UE-corresponding. That is, one UE records one UPF priority value in the PCF.

[0137] Optionally, modifying the status value of the pre-recorded N4 link according to the first indication information includes:

[0138] According to the first indication information, modifying the status value of the pre-recorded N4 link to the first preset value;

[0139] Sending the modified status value of the N4 link and the pre-recorded UPF priority value to the SMF includes:

[0140] Receiving a first policy control request message sent by the SMF after the first terminal device UE is back online;

[0141] Sending a first policy and charging control rule to the SMF, where the first policy and charging control rule includes the status value of the N4 link with a value of the first preset value and the UPF priority value with a value of the second preset value, and the second preset value is used to indicate that the UPF carrying the current bearer service is the first user plane function network element UPF.

[0142] Among them, the aforementioned first indication information received by the PCF includes the status value of the N4 link with a value of the first preset value. Therefore, the status value of the N4 link modified by the PCF is the first preset value; the aforementioned pre-recorded UPF priority value indicates that the UPF carrying the current bearer service is the first UPF. Therefore, this pre-recorded UPF priority value is the second preset value.

[0143] As can be seen from the above, the status value of the N4 link with a value of the first preset value and the UPF priority value with a value of the second preset value can be carried by the PCF in the PCC rule and returned to the SMF during the process of the SMF requesting a policy and charging control rule (Policy and Charging Control Rule - PCC Rule) from the PCF.

[0144] Optionally, after the service carried by the first user plane function network element UPF is switched to the second UPF, the method further includes:

[0145] Receiving second indication information sent by the SMF when the second UE needs to go offline and the second UPF has not failed, where the second UE is one of the UEs to which the service carried by the second UPF belongs, and the second indication information is used to indicate that the N4 link between the SMF and the first user plane function network element UPF has not been disconnected;

[0146] According to the second indication information, modifying the status value of the N4 link and the UPF priority value.

[0147] It should be noted here that the above "the second UE needs to go offline" is the normal offline process of the second UE, rather than being triggered by a UPF failure.

[0148] As can be seen from the above, after the service carried by the first UPF is switched to the second UPF, if one of the UEs on the second UPF needs to go offline normally and the second UPF does not fail at this time (that is, the N4 link between the second UPF and the SMF is not disconnected), the SMF can send the above second indication information to the PCF so that the PCF can modify the status value of the N4 link and the UPF priority value.

[0149] Among them, when the PCF receives the second indication information, the N4 link between the second UPF and the SMF is not disconnected, and the UPF currently carrying the service is the second UPF. Therefore, after the PCF receives the second indication information, it needs to modify the status value of the N4 link to a value indicating that the N4 link between the second UPF and the SMF is not disconnected, and modify the UPF priority value to a value indicating that the UPF currently carrying the service is the second UPF.

[0150] That is, as can be seen from the above content, when a UE needs to go offline (including normal offline and offline triggered by the failure of the UPF currently carrying the service), the PCF modifies the status value of the N4 link according to the indication information sent by the SMF indicating the actual status of the N4 link between the UPF currently carrying the service and the SMF; and the PCF only modifies the UPF priority value when the UE goes offline normally.

[0151] Optionally, the second indication information includes the status value of the N4 link with a third preset value, and the third preset value is used to indicate that the N4 link between the SMF and the second UPF is not disconnected;

[0152] The process of receiving the second indication information includes:

[0153] Receiving a second request message sent by the SMF to delete the session of the second UE, where the second request message carries the status value of the N4 link with the third preset value.

[0154] It can be seen from this that when the second UE normally goes offline from the second UPF, if the second UPF does not fail, that is, the N4 link between the second UPF and the SMF is not broken, the SMF can deactivate the second UE, that is, the SMF can send a session deletion request message for the second UE to the PCF and carry the status value of the N4 link with the third preset value in the session deletion request message to inform the PCF that the N4 link between the second UPF currently carrying the service and the SMF is not disconnected.

[0155] Optionally, after receiving the second request message for deleting the session of the second UE sent by the SMF, the method further includes:

[0156] Deleting the session of the second UE.

[0157] That is, after the PCF receives the second request message for deleting the session of the second UE, it can delete the session of the second UE to deactivate the second UE.

[0158] Optionally, the modifying the status value of the N4 link and the UPF priority value according to the second indication information includes:

[0159] According to the second indication information, modifying the status value of the N4 link to a third preset value and modifying the UPF priority value to a fourth preset value, where the third preset value is used to indicate that the N4 link between the SMF and the second UPF is not disconnected, and the fourth preset value is used to indicate that the UPF currently carrying the service is the second UPF.

[0160] That is, in the embodiment of the present invention, an N4 link status value with a value of the third preset value is used to indicate that the N4 link between the SMF and the second UPF is disconnected; a UPR priority value with a value of the fourth preset value is used to indicate that the UPF currently carrying the service is the second UPF.

[0161] Optionally, after receiving the second indication information, the method further includes:

[0162] After the second UE goes online again, sending the status value of the N4 link and the UPF priority value modified most recently to the SMF, so that the SMF sets the second UPF to carry the service of the second UE according to the status value of the N4 link and the UPF priority value modified most recently.

[0163] It can be seen from this that if the second UE needs to go online again after being normally offline from the second UPF, the SMF can obtain the status value of the N4 link and the UPF priority value modified most recently by the PCF from the PCF, and thus set the second UPF to carry the service of the second UE according to the status value of the N4 link and the UPF priority value modified most recently by the PCF.

[0164] Optionally, the sending the status value of the N4 link and the UPF priority value modified most recently to the SMF includes:

[0165] Receiving a second policy control request message sent by the SMF;

[0166] Send a second policy and charging control rule to the SMF, where the second policy and charging control rule includes a status value of the N4 link with a third preset value and a UPF priority value with a fourth preset value. The third preset value is used to indicate that the N4 link between the SMF and the second UPF is not disconnected, and the fourth preset value is used to indicate that the UPF carrying the current service is the second UPF.

[0167] Wherein, the status value of the N4 link after the PCF's most recent modification is the third preset value, and the UPF priority value after the most recent modification is the fourth preset value.

[0168] It can be seen therefrom that the status value of the N4 link with the third preset value and the UPF priority value with the fourth preset value can be carried by the PCF in the PCC rule and returned to the SMF during the process of the SMF requesting the PCC rule from the PCF.

[0169] In summary, the specific implementation of the service switching method according to the embodiments of the present invention can be described as follows:

[0170] As Figure 4 shown, the UE initiates a session establishment process through the following steps 401 to 403:

[0171] Step 401: The UE (i.e., the 5G terminal) initiates a registration service to complete network registration;

[0172] Step 402: The UE sends a PDU session establishment request to the AMF;

[0173] Step 403: The AMF sends the received PDU session establishment request to the SMF;

[0174] Step 404: The SMF interacts with a Unified Data Management (UDM) network element to query subscription data;

[0175] First aspect: In the case of a failure of the primary UPF, the UE is automatically switched from the primary UPF to the secondary UPF through the following steps 405 to step 412:

[0176] Step 405: The SMF detects that the primary UPF has failed and sends a first request message to the PCF to delete the UE's session. That is, the SMF sends, via the session policy control delete request (Npcf_SMPolicyControlAPI_SmPolicyControlDelete Request) message in the session policy control application programming interface (API) of the PCF, N4-State = 1 to the PCF. The first request message carries "N4-State = 1 (i.e., the status value of the N4 link = 1)". N4-State = 1 indicates that the N4 link between the UPF currently carrying the service (i.e., the primary UPF) and the SMF is disconnected;

[0177] Step 406: The PCF modifies the value of the locally recorded N4-State to "1" and deletes the UE's session;

[0178] Step 407: After the SMF detects that the UE has come back online (i.e., after the SMF receives again the session establishment request of the UE forwarded by the AMF), the SMF sends a policy control request to the PCF. After the UE goes offline due to the failure of the primary UPF, it will automatically come back online;

[0179] Step 408: The PCF returns a PCC rule to the SMF. The PCC rule includes "N4-State = 1 and Priority = 0". That is, the PCF returns N4-State = 1 and Priority = 0 to the SMF via the session policy control create response (Npcf_SMPolicyControlAPI_SmPolicyControlCreate Response) message in the session policy control API of the PCF. Here, Priority is the UPF priority value, indicating the UPF currently carrying the service. When Priority = 0 recorded in the PCF, it means the UPF currently carrying the service is the primary UPF. When Priority = 1 recorded in the PCF, it means the UPF currently carrying the service is the secondary UPF;

[0180] Step 409: The SMF selects the UPF to be switched according to "N4-State = 1 and Priority = 0", that is, the SMF performs an exclusive OR operation on the received "N4-State = 1 and Priority = 0" (that is, performs an exclusive OR on 1 and 0), and the result is "1". Then, according to the network topology selection mechanism, a group of available UPFs are selected through TAC, DNN, and network slice, and the UPF with a priority value of "1" in this group of UPFs is selected as the UPF to be switched. Among them, a group of UPFs includes a primary UPF and a standby UPF, and different UPFs have different priority values (Priority). The UPF with a priority value of 1 is the standby UPF, and the UPF with a priority value of 0 is the primary UPF. In addition, the priority values of the primary and standby UPFs can be pre-configured in the SMF by adding a DNN (ADD PNFDNN) command that supports the peer network function;

[0181] Step 410: The SMF interacts with the standby UPF so that the standby UPF allocates a dedicated IP address for the UE and completes the PDU session establishment, that is, the SMF sends a Packet Forwarding Control Protocol (PFCP) session message for the establishment completion packet to the standby UPF, and the standby UPF responds to the establishment PFCP session message, allocates a dedicated IP address for the UE, and completes the PDU session establishment;

[0182] Step 411: The SMF interacts with the AMF and RAN to send the IP address allocated by the standby UPF to the UE;

[0183] Step 412: The UE interacts with the RAN and the standby UPF to access the enterprise intranet.

[0184] In the second aspect, after step 412, if the UE needs to go offline from the standby UPF, the following steps 413 to 414 are executed to deactivate the UE:

[0185] Step 413: When the UE needs to go offline from the standby UPF, if the SMF detects that the standby UPF has not failed, it sends a second request message to the PCF to delete the UE's session. The second request message carries "N4-State = 0 (that is, the status value of the N4 link = 0)", and N4-State = 0 means that the N4 link between the current UPF carrying the service (that is, the standby UPF) and the SMF is not disconnected;

[0186] Step 414: The PCF modifies the value of the locally recorded N4-State to "0", modifies the value of the locally recorded Priority to "1", and deletes the UE's session.

[0187] Thirdly, after step 414, if the UE reconnects to the network and the standby UPF does not fail, then perform the following steps 415 to 420 to enable the standby UPF to carry the UE's services:

[0188] Step 415: When the UE reconnects to the network, the SMF sends a policy control request to the PCF;

[0189] Step 416: The PCF returns a PCC rule to the SMF. The PCC rule includes "N4-State = 0 and Priority = 1";

[0190] Step 417: The SMF selects the UPF to be switched according to "N4-State = 0 and Priority = 1", that is, the SMF performs an exclusive OR operation on the received "N4-State = 0 and Priority = 1" (that is, performs an exclusive OR on 1 and 0), and the obtained result is "1", and selects a group of available UPFs through TAC, DNN, and network slice, and then selects the UPF with the priority value of "1" in this group of UPFs (that is, the standby UPF) as the UPF carrying the UE's services;

[0191] Step 418: The SMF interacts with the standby UPF so that the standby UPF allocates a dedicated IP address for the UE and completes the PDU session establishment, that is, the SMF sends a PFCP session establishment message to the standby UPF, and the standby UPF responds to the PFCP session establishment message, allocates a dedicated IP address for the UE, and completes the PDU session establishment;

[0192] Step 419: The SMF interacts with the AMF and RAN to send the IP address allocated by the standby UPF to the UE;

[0193] Step 420: The UE interacts with the RAN and the standby UPF to access the enterprise intranet.

[0194] Fourthly: After step 420, that is, during the process of the UE accessing the enterprise intranet through the standby UPF, if the standby UPF fails, then as Figure 5 shown, perform the following steps 501 to 508 to switch the UE from the standby UPF to the primary UPF:

[0195] Step 501: When the SMF detects that the standby UPF fails, it sends a third request message to the PCF to delete the UE's session. Among them, the third request message carries "N4-State = 1", and N4-State = 1 indicates that the N4 link between the current UPF carrying the service (that is, the standby UPF) and the SMF is disconnected;

[0196] Step 502: The PCF modifies the value of the locally recorded N4-State to "1" and deletes the UE's session;

[0197] Step 503: After the SMF detects that the UE has come back online, it sends a policy control request to the PCF. After the UE goes offline due to a standby UPF failure, it will automatically come back online;

[0198] Step 504: The PCF returns a PCC rule to the SMF. The PCC rule includes "N4-State = 1 and Priority = 1". Here, Priority is the UPF priority value, indicating the UPF currently carrying the service. When Priority = 1, it means the UPF currently carrying the service is the standby UPF;

[0199] Step 505: The SMF selects the UPF to be switched according to "N4-State = 1 and Priority = 1", that is, the SMF performs an exclusive OR operation on the received "N4-State = 1 and Priority = 1" (that is, performs an exclusive OR on 1 and 1), and the result is "0". Then, it selects a group of available UPFs through TAC, DNN, and network slice, and then selects the UPF with a priority value of "0" (that is, the primary UPF) in this group of UPFs as the UPF to be switched;

[0200] Step 506: The SMF interacts with the primary UPF so that the primary UPF assigns a dedicated IP address to the UE and completes the PDU session establishment. That is, the SMF sends a PFCP session establishment message to the primary UPF, and the primary UPF responds to this PFCP session establishment message, assigns a dedicated IP address to the UE, and completes the PDU session establishment;

[0201] Step 507: The SMF interacts with the AMF and the RAN to send the IP address assigned by the primary UPF to the UE;

[0202] Step 508: The UE interacts with the RAN and the primary UPF to access the enterprise intranet.

[0203] In a fifth aspect, after step 508, if the UE needs to go offline from the primary UPF, the following steps 509 to 510 are executed to deactivate the UE:

[0204] Step 509: When the UE needs to go offline from the primary UPF, if the SMF detects that the primary UPF has not failed, it sends a fourth request message to the PCF to delete the UE's session. The fourth request message carries "N4-State = 0 (that is, the status value of the N4 link = 0)". N4-State = 0 means that the N4 link between the current UPF carrying the service (that is, the primary UPF) and the SMF is not disconnected;

[0205] Step 510: The PCF modifies the value of the locally recorded N4-State to "0", modifies the value of the locally recorded Priority to "0", and deletes the UE's session.

[0206] In a sixth aspect, after step 510, if the UE goes online again and the primary UPF does not fail, the following steps 511 to 516 are executed to enable the primary UPF to carry the UE's service:

[0207] Step 511: When the UE goes online again, the SMF sends a policy control request to the PCF;

[0208] Step 512: The PCF returns a PCC rule to the SMF, and the PCC rule includes "N4-State = 0 and Priority = 0";

[0209] Step 513: The SMF selects the UPF to be switched according to "N4-State = 0 and Priority = 0", that is, the SMF performs an exclusive OR operation on the received "N4-State = 0 and Priority = 0" (that is, performs an exclusive OR on 0 and 0), and the result obtained is "0", and a group of serviceable UPFs are selected through the TAC, DNN, and network slice, and then the UPF with the priority value of "0" in this group of UPFs (that is, the primary UPF) is selected as the UPF carrying the UE's service;

[0210] Step 514: The SMF interacts with the primary UPF so that the primary UPF allocates a dedicated IP address for the UE and completes the PDU session establishment, that is, the SMF sends a PFCP session establishment message to the primary UPF, and the primary UPF responds to the PFCP session establishment message, allocates a dedicated IP address for the UE, and completes the PDU session establishment;

[0211] Step 515: The SMF interacts with the AMF and the RAN to send the IP address allocated by the primary UPF to the UE;

[0212] Step 516: The UE interacts with the RAN and the primary UPF to access the enterprise intranet.

[0213] As can be seen from the above, in the embodiments of the present invention, a primary / backup UPF identification method and a primary / backup UPF automatic switching switch are defined.

[0214] 1. Regarding the identification of the primary / backup UPF:

[0215] When performing service activation, in the configuration command for the SMF to select the UPF, configure the Priority of the UPF to distinguish between the primary and standby UPFs. That is, the primary and standby UPFs can be pre-distinguished on the SMF by defining the Priority. Priority supports two values, for example, 0 and 1 respectively. The smaller the value, the higher the priority. When Priority = 0, it means the corresponding UPF is the primary one. When Priority = 1, it means the corresponding UPF is the standby one.

[0216] 2. Regarding the automatic switch for the primary and standby UPFs:

[0217] Determine whether to perform the primary and standby UPF switch by defining the N4-State field. The N4-State field has two values: 0 (default value), 1. Among them, N4-State = 0 turns off the automatic UPF switch, indicating that the primary and standby UPF switch is not allowed. That is, when N4-State = 0, it means the N4 link between the currently bearer service UPF and the SMF is not disconnected, and there is no need for automatic UPF switch. N4-State = 1 turns on the automatic UPF switch, indicating that the primary and standby UPF switch is allowed. That is, when N4-State = 1, it means the N4 link between the currently bearer service UPF and the SMF is disconnected, and an automatic UPF switch is required.

[0218] In this way, the SMF introduces Priority through transformation and marks the primary and standby for the dual UPFs in the customized network. Then, when a single UPF device-level failure occurs, all UEs anchored on this UPF will be deactivated. Thus, during the UE offline process, when the PCF deletes the UE session, the PCF can modify the N4-State value in the dynamic cache space according to the cause value carried by the SMF (i.e., the cause value used to indicate whether the UE goes offline normally or due to UPF failure). After the UE reconnects, the SMF queries the PCF to obtain the latest N4-State and Priority, and determines whether to switch to the standby UPF to anchor and obtain the IP address according to the exclusive OR operation value of the two fields, thereby realizing the automatic switch function of the primary and standby UPFs.

[0219] That is, in the embodiments of the present invention, by adding Priority on the SMF to implement the primary / backup distinction in the disaster recovery networking of the customized network with dual UPFs, and by modifying and increasing the N4-State dynamic cache space and pre-configuring the Priority rule on the PCF. In this way, when the primary UPF has a device-level failure, the UE goes offline first, the PCF records and modifies the N4-State value. After the UE goes online again, the PCF sends the latest N4-State and Priority fields to the SMF, and then the SMF selects the UPF with the corresponding priority value according to the exclusive OR operation value of the TAC, DNN, slice, and the newly added N4-State and Priority, so as to automatically migrate the service to the standby UPF, completing the rapid recovery of the user service.

[0220] In summary, the embodiments of the present invention have the following advantages:

[0221] 1. In the prior art, in the ordinary disaster recovery solution of the customized network, only the protection of the link layer is mainly considered, and the device-level disaster recovery protection of the UPF is not considered. However, the embodiments of the present invention can provide the UPF device-level protection function;

[0222] 2. In the prior art, when a single UPF device fails, the service recovery means are relatively primitive, and the service can only be migrated by manually modifying the network configuration or subscribing to a dual DNN for the UE. The service recovery ability is weak. In the embodiments of the present invention, the automatic switching of the service can be realized. On the one hand, it can liberate the human resource input of the maintenance personnel. On the other hand, it can quickly recover the interrupted service of the user, greatly reducing the degree of loss of the customer's interests;

[0223] 3. The embodiments of the present invention make more full use of the network function entity (Network Function, NF) resources of the 5GC itself. By adding the form of a cell field to implement the dynamic selection of the UPF function, without adding additional NFs, it can ensure the security and stability of the 5GC.

[0224] The above introduces the service switching method provided by the embodiments of the present invention. Next, the service switching device provided by the embodiments of the present invention will be introduced in conjunction with the accompanying drawings.

[0225] See Figure 6 , the embodiments of the present invention also provide a service switching device, which is applied to the SMF. The device includes:

[0226] The first sending module 601 is used for, when detecting that the first user plane function network element UPF carrying the service has a failure, sending a first indication message to the policy control function network element PCF, where the first indication message is used to indicate that the N4 link between the SMF and the first user plane function network element UPF is disconnected, and to indicate the PCF to modify the pre-recorded state value of the N4 link;

[0227] A first receiving module 602, configured to receive the modified status value of the N4 link sent by the PCF and a pre-recorded UPF priority value, where the UPF priority value is used to indicate the UPF carrying the current bearer service;

[0228] A first switching module 603, configured to switch the service carried by the first user plane function network element UPF to a second UPF according to the modified status value of the N4 link and the pre-recorded UPF priority value.

[0229] Optionally, the first indication information includes the status value of the N4 link with a value of a first preset value, and the first preset value is used to indicate that the N4 link between the SMF and the first user plane function network element UPF is disconnected;

[0230] The first sending module is specifically configured to:

[0231] Send a first request message for deleting the session of the first terminal device UE to the PCF, where the first terminal device UE is one of the UEs to which the service carried by the first user plane function network element UPF belongs, and the first request message carries the status value of the N4 link with a value of the first preset value.

[0232] Optionally, the first receiving module includes:

[0233] A first request sub-module, configured to send a first policy control request message to the PCF after the first terminal device UE goes online again;

[0234] A first receiving sub-module, configured to receive the first policy and charging control rules sent by the PCF, where the first policy and charging control rules include the status value of the N4 link with a value of the first preset value and a UPF priority value with a value of a second preset value, and the second preset value is used to indicate that the UPF carrying the current bearer service is the first user plane function network element UPF.

[0235] Optionally, the first switching module includes:

[0236] A first operator sub-module, configured to perform an operation on the first preset value and the second preset value according to a preset operation rule to obtain a first operation result;

[0237] A first switching sub-module, configured to switch the service of the first terminal device UE carried by the first user plane function network element UPF to a second UPF according to the first operation result.

[0238] Optionally, the first switching sub-module is specifically configured to:

[0239] Obtain the tracking area identifier of the cell where the first terminal device UE is located, the data network name of the network where the first terminal device UE is located, and the first network slice;

[0240] Select a UPF packet associated with the UPF packet associated with the tracking area identifier, the data network name, and the first network slice, where one UPF packet includes two UPFs with different priority values;

[0241] Determine the UPF with the same priority value as the first operation result in the selected group of UPFs as the second UPF;

[0242] Switch the service carried by the first user plane function network element UPF to the second UPF.

[0243] Optionally, the device further includes:

[0244] A third sending module, configured to send second indication information to the PCF when the second UE needs to go offline and the second UPF does not fail, where the second indication information is used to indicate that the N4 link between the SMF and the first user plane function network element UPF is not disconnected, and to indicate that the PCF modifies the status value of the N4 link and the UPF priority value;

[0245] Wherein, the second UE is one of the UEs to which the service carried on the second UPF belongs.

[0246] Optionally, the second indication information includes the status value of the N4 link with a third preset value, and the third preset value is used to indicate that the N4 link between the SMF and the second UPF is not disconnected; the third sending module is specifically configured to:

[0247] Send a second request message for deleting the session of the second UE to the PCF, where the second request message carries the status value of the N4 link with the third preset value.

[0248] Optionally, the device further includes:

[0249] A third receiving module, configured to receive the status value of the N4 link and the UPF priority value modified most recently sent by the PCF after the second UE goes online again;

[0250] A setting module, configured to set the second UPF to carry the service of the second UE according to the status value of the N4 link and the UPF priority value modified most recently.

[0251] Optionally, the third receiving module includes:

[0252] A second request sub-module, configured to send a second policy control request message to the PCF;

[0253] A second receiving sub-module, configured to receive a second policy and charging control rule sent by the PCF, where the second policy and charging control rule includes a status value of the N4 link with a value of a third preset value, and a UPF priority value with a value of a fourth preset value, and the third preset value is used to indicate that the N4 link between the SMF and the second UPF is not disconnected, and the fourth preset value is used to indicate that the UPF carrying the current service is the second UPF.

[0254] Optionally, the setting module includes:

[0255] A second operator sub-module, configured to perform an operation on the third preset value and the fourth preset value according to a preset operation rule to obtain a second operation result;

[0256] A setting sub-module, configured to set the second UPF to carry the service of the second UE according to the second operation result.

[0257] See Figure 7 , an embodiment of the present invention further provides a service switching device, which is applied to a PCF, and the device includes:

[0258] A second receiving module 701, configured to receive first indication information sent by a session management function network element SMF when a first user plane function network element UPF carrying the current service fails, where the first indication information is used to indicate that the N4 link between the SMF and the first user plane function network element UPF is disconnected;

[0259] A first modification module 702, configured to modify a pre-recorded status value of the N4 link according to the first indication information;

[0260] A second sending module 703, configured to send the modified status value of the N4 link and a pre-recorded UPF priority value to the SMF, so that the SMF switches the service carried by the first user plane function network element UPF to the second UPF according to the modified status value of the N4 link and the pre-recorded UPF priority value, where the UPF priority value is used to indicate the UPF carrying the current service.

[0261] Optionally, the first indication information includes a status value of the N4 link with a value of a first preset value, and the first preset value is used to indicate that the N4 link between the SMF and the first user plane function network element UPF is disconnected; specifically, the second receiving module is used for:

[0262] Receive a first request message for deleting a session of a first user equipment (UE) sent by the SMF, where the first UE is one of the UEs to which the services carried on the first user plane function network element (UPF) belong, and the first request message carries a status value of the N4 link with a value of the first preset value.

[0263] Optionally, the apparatus further includes:

[0264] A first deletion module, configured to delete the session of the first UE.

[0265] Optionally, the first modification module is specifically configured to:

[0266] Modify a pre-recorded status value of the N4 link to the first preset value according to the first indication information;

[0267] The second sending module is specifically configured to:

[0268] Receive a first policy control request message sent by the SMF after the first UE comes back online;

[0269] Send a first policy and charging control rule to the SMF, where the first policy and charging control rule includes a status value of the N4 link with a value of the first preset value and a UPF priority value with a value of a second preset value, and the second preset value is used to indicate that the UPF currently carrying services is the first UPF.

[0270] Optionally, the apparatus further includes:

[0271] A fourth receiving module, configured to receive second indication information sent by the SMF when a second UE needs to go offline and the second UPF does not fail, where the second UE is one of the UEs to which the services carried on the second UPF belong, and the second indication information is used to indicate that the N4 link between the SMF and the first UPF is not disconnected;

[0272] A second modification module, configured to modify the status value of the N4 link and the UPF priority value according to the second indication information.

[0273] Optionally, the second indication information includes a status value of the N4 link with a value of a third preset value, and the third preset value is used to indicate that the N4 link between the SMF and the second UPF is not disconnected; the fourth receiving module is specifically configured to:

[0274] Receive a second request message for deleting the session of the second UE sent by the SMF, where the second request message carries a status value of the N4 link with a value of the third preset value.

[0275] Optionally, the apparatus further includes:

[0276] A second deletion module, configured to delete the session of the second UE.

[0277] Optionally, the second modification module is specifically configured to:

[0278] According to the second indication information, modify the status value of the N4 link to a third preset value, and modify the UPF priority value to a fourth preset value, where the third preset value is used to indicate that the N4 link between the SMF and the second UPF is not disconnected, and the fourth preset value is used to indicate that the UPF currently carrying the service is the second UPF.

[0279] Optionally, the apparatus further includes:

[0280] A fourth sending module, configured to, after the second UE goes online again, send the status value of the N4 link and the UPF priority value modified most recently to the SMF, so that the SMF sets the second UPF to carry the service of the second UE according to the status value of the N4 link and the UPF priority value modified most recently.

[0281] Optionally, the fourth sending module is specifically configured to:

[0282] Receive a second policy control request message sent by the SMF;

[0283] Send a second policy and charging control rule to the SMF, where the second policy and charging control rule includes the status value of the N4 link with a value of the third preset value, and the UPF priority value with a value of the fourth preset value, where the third preset value is used to indicate that the N4 link between the SMF and the second UPF is not disconnected, and the fourth preset value is used to indicate that the UPF currently carrying the service is the second UPF.

[0284] It should be noted that the division of units in the embodiments of the present application is illustrative, and is only a logical function division. In actual implementation, there may be other division methods. In addition, in each embodiment of the present application, each functional unit may be integrated into one processing unit, or each unit may exist physically alone, or two or more units may be integrated into one unit. The above integrated units may be implemented in the form of hardware or in the form of software functional units.

[0285] When the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a processor-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or all or part of this technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions for causing a computer device (which can be a personal computer, a server, or a network device, etc.) or a processor to execute all or part of the steps of the methods described in various embodiments of this application. The aforementioned storage medium includes: various media such as USB flash drives, mobile hard disks, read-only memories (ROMs), random access memories (RAMs), magnetic disks, or optical discs that can store program codes.

[0286] It should be noted here that the above-mentioned device provided in the embodiments of the present invention can implement all the method steps implemented in the above method embodiments and can achieve the same technical effects. Therefore, the same parts and beneficial effects as those in the method embodiments will not be specifically described in this embodiment.

[0287] Embodiments of the present invention also provide a network device, such as Figure 8 shown. This network device includes a memory 820, a transceiver 810, and a processor 800;

[0288] The memory 820 is used to store computer programs;

[0289] The transceiver 810 is used to receive and send data under the control of the processor 800;

[0290] In a first aspect, when the network device acts as an SMF, the processor 800 is used to read the computer program in the memory 820 and execute the service switching method described in the first aspect above;

[0291] In a second aspect, when the network device acts as a PCF, the processor 800 is used to read the computer program in the memory 820 and execute the service switching method described in the second aspect above.

[0292] Among them, in Figure 8Among them, the bus architecture may include any number of interconnected buses and bridges, specifically, various circuits represented by one or more processors represented by processor 800 and a memory represented by memory 820 are linked together. The bus architecture may also link together various other circuits such as peripheral devices, voltage regulators, and power management circuits, which are well known in the art, and thus will not be further described herein. The bus interface provides an interface. The transceiver 810 may be multiple components, that is, including a transmitter and a receiver, and provides a unit for communicating with various other devices on a transmission medium, and these transmission media include wireless channels, wired channels, optical fiber cables, and other transmission media. The processor 800 is responsible for managing the bus architecture and general processing, and the memory 820 may store data used by the processor 800 when performing operations.

[0293] The processor 800 may be a central processing unit (CPU), an application specific integrated circuit (ASIC), a field-programmable gate array (FPGA), or a complex programmable logic device (CPLD). The processor 800 may also adopt a multi-core architecture.

[0294] It should be noted here that the above device provided by the embodiments of the present invention can implement all the method steps implemented by the above method embodiments, and can achieve the same technical effects. The same parts and beneficial effects as those in the method embodiments will not be specifically described in this embodiment.

[0295] The embodiments of the present invention also provide a processor-readable storage medium. The processor-readable storage medium stores a computer program, and the computer program is used to cause the processor to execute the above-mentioned service switching method.

[0296] The processor-readable storage medium may be any available medium or data storage device accessible by the processor, including but not limited to magnetic memories (such as floppy disks, hard disks, magnetic tapes, magneto-optical discs (MO), etc.), optical memories (such as CDs, DVDs, BDs, HVDs, etc.), and semiconductor memories (such as ROMs, EPROMs, EEPROMs, non-volatile memories (NAND FLASH), solid state drives (SSD)).

[0297] Those skilled in the art should understand that the embodiments of the present application can be provided as a method, a system, or a computer program product. Therefore, the present application can take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware aspects. Moreover, the present application can take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage and optical storage, etc.) that contain computer-usable program code.

[0298] The present application is described with reference to the flowcharts and / or block diagrams of methods, apparatuses (systems), and computer program products according to the embodiments of the present application. It should be understood that each flow and / or block in the flowchart and / or block diagram, as well as the combination of flows and / or blocks in the flowchart and / or block diagram, can be implemented by computer-executable instructions. These computer-executable instructions can be provided to the processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing devices to generate a machine, such that the instructions executed by the processor of the computer or other programmable data processing devices generate means for implementing the functions specified in Figure 1 one flow or multiple flows and / or blocks Figure 1 one block or multiple blocks.

[0299] These processor-executable instructions can also be stored in a processor-readable memory that can direct a computer or other programmable data processing device to work in a specific manner, such that the instructions stored in the processor-readable memory generate a manufactured article including instruction means that implement the functions specified in Figure 1 one flow or multiple flows and / or blocks Figure 1 one block or multiple blocks.

[0300] These processor-executable instructions can also be loaded onto a computer or other programmable data processing device, such that a series of operation steps are executed on the computer or other programmable device to generate a computer-implemented process, and thus the instructions executed on the computer or other programmable device provide steps for implementing the functions specified in Figure 1 one flow or multiple flows and / or blocks Figure 1 one block or multiple blocks.

[0301] Obviously, those skilled in the art can make various modifications and variations to the present application without departing from the spirit and scope of the present application. Thus, if these modifications and variations of the present application fall within the scope of the claims of the present application and their equivalent technologies, the present application is also intended to include these modifications and variations.

Claims

1. A service switching method, characterized in that, applied to a Session Management Function network element (SMF), the method includes: in the case of detecting a failure of a first User Plane Function network element (UPF) that currently bears a service, sending a first indication message to a Policy Control Function network element (PCF), wherein the first indication message is used to indicate that the N4 link between the SMF and the first UPF is disconnected, and to indicate that the PCF modifies a pre-recorded status value of the N4 link; receiving the modified status value of the N4 link and the pre-recorded UPF priority value sent by the PCF, wherein the UPF priority value is used to indicate the UPF that currently bears the service; switching the service borne by the first UPF to a second UPF according to the modified status value of the N4 link and the pre-recorded UPF priority value; wherein the first indication message includes the status value of the N4 link with a value of a first preset value, and the first preset value is used to indicate that the N4 link between the SMF and the first UPF is disconnected; sending the first indication message to the PCF includes: sending a first request message to delete the session of a first User Equipment (UE) to the PCF, wherein the first UE is one of the UEs to which the service borne by the first UPF belongs, and the first request message carries the status value of the N4 link with a value of the first preset value.

2. The service switching method according to claim 1, characterized in that, the receiving the modified status value of the N4 link and the pre-recorded UPF priority value sent by the PCF includes: after the first UE is re-connected to the network, sending a first Policy Control Request message to the PCF; receiving the first Policy and Charging Control Rule sent by the PCF, wherein the first Policy and Charging Control Rule includes the status value of the N4 link with a value of the first preset value and the UPF priority value with a value of a second preset value, and the second preset value is used to indicate that the UPF that currently bears the service is the first UPF.

3. The service switching method according to claim 2, characterized in that, the process of switching the service of the first UE borne by the first UPF to a second UPF according to the modified status value of the N4 link and the pre-recorded UPF priority value includes: performing an operation on the first preset value and the second preset value according to a preset operation rule to obtain a first operation result; switching the service of the first UE borne by the first UPF to a second UPF according to the first operation result.

4. The service switching method according to claim 3, characterized in that, the switching the service of the first UE borne by the first UPF to a second UPF according to the first operation result includes: Obtain the tracking area identifier of the cell where the first terminal device UE is located, the data network name of the network where the first terminal device UE is located, and the first network slice; Select a UPF packet associated with the tracking area identifier, the data network name, and the first network slice, where a UPF packet includes two UPFs with different priority values; Determine the UPF with the same priority value as the first operation result in the selected group of UPFs as the second UPF; Switch the service of the first terminal device UE carried by the first user plane function network element UPF to the second UPF.

5. The service switching method according to claim 1, characterized in that, After switching the service carried by the first user plane function network element UPF to the second UPF, the method further includes: In the case where the second UE needs to go offline and the second UPF does not fail, send second indication information to the PCF, where the second indication information is used to indicate that the N4 link between the SMF and the first user plane function network element UPF is not disconnected, and to indicate that the PCF modifies the status value of the N4 link and the UPF priority value; wherein the second UE is one of the UEs to which the service carried by the second UPF belongs.

6. The service switching method according to claim 5, characterized in that, The second indication information includes the status value of the N4 link with a third preset value, and the third preset value is used to indicate that the N4 link between the SMF and the second UPF is not disconnected; The sending the second indication information to the PCF includes: Sending a second request message to the PCF to delete the session of the second UE, where the second request message carries the status value of the N4 link with the third preset value.

7. The service switching method according to claim 5, characterized in that, After sending the second indication information to the PCF, the method further includes: After the second UE goes online again, receive the status value of the N4 link and the UPF priority value modified most recently sent by the PCF; Set the second UPF to carry the service of the second UE according to the status value of the N4 link and the UPF priority value modified most recently.

8. The service switching method according to claim 7, characterized in that, The receiving the status value of the N4 link and the UPF priority value modified most recently sent by the PCF includes: Sending a second policy control request message to the PCF; Receiving the second policy and charging control rule sent by the PCF, where the second policy and charging control rule includes the status value of the N4 link with a third preset value, and the UPF priority value with a fourth preset value, the third preset value is used to indicate that the N4 link between the SMF and the second UPF is not disconnected, and the fourth preset value is used to indicate that the UPF currently carrying the service is the second UPF.

9. The service switching method according to claim 8, wherein, setting the second UPF to carry the service of the second UE according to the status value of the N4 link after the most recent modification and the UPF priority value includes: performing an operation on the third preset value and the fourth preset value according to a preset operation rule to obtain a second operation result; setting the second UPF to carry the service of the second UE according to the second operation result.

10. A service switching method, wherein, applied to a Policy Control Function network element (PCF), the method includes: receiving first indication information sent by a Session Management Function network element (SMF) when a first User Plane Function network element (UPF) that is currently carrying a service fails, wherein the first indication information is used to indicate that the N4 link between the SMF and the first UPF is disconnected; modifying the status value of the pre-recorded N4 link according to the first indication information; sending the modified status value of the N4 link and the pre-recorded UPF priority value to the SMF, so that the SMF switches the service carried by the first UPF to the second UPF according to the modified status value of the N4 link and the pre-recorded UPF priority value, wherein the UPF priority value is used to indicate the UPF that is currently carrying the service; wherein, the first indication information includes the status value of the N4 link with a value of a first preset value, and the first preset value is used to indicate that the N4 link between the SMF and the first UPF is disconnected; The process of receiving the first indication information includes: receiving a first request message for deleting the session of a first User Equipment (UE) sent by the SMF, wherein the first UE is one of the UEs to which the service carried by the first UPF belongs, and the first request message carries the status value of the N4 link with a value of the first preset value.

11. The service switching method according to claim 10, wherein, after receiving the first request message for deleting the session of the first UE sent by the SMF, the method further includes: deleting the session of the first UE.

12. The service switching method according to claim 10, wherein, modifying the status value of the pre-recorded N4 link according to the first indication information includes: modifying the status value of the pre-recorded N4 link to the first preset value according to the first indication information; sending the modified status value of the N4 link and the pre-recorded UPF priority value to the SMF includes: receiving a first policy control request message sent by the SMF after the first UE is back online. Send a first policy and charging control rule to the SMF, where the first policy and charging control rule includes a status value of the N4 link with a value of the first preset value and a UPF priority value with a value of a second preset value, and the second preset value is used to indicate that the UPF carrying the current bearer service is the first user plane function network element UPF.

13. The service handover method according to claim 10, wherein, after the service carried by the first user plane function network element UPF is handed over to a second UPF, the method further includes: receiving second indication information sent by the SMF when a second UE needs to go offline and the second UPF does not fail, where the second UE is one of the UEs to which the service carried on the second UPF belongs, and the second indication information is used to indicate that the N4 link between the SMF and the first user plane function network element UPF is not disconnected; modifying the status value of the N4 link and the UPF priority value according to the second indication information.

14. The service handover method according to claim 13, wherein, the second indication information includes a status value of the N4 link with a value of a third preset value, and the third preset value is used to indicate that the N4 link between the SMF and the second UPF is not disconnected; The process of receiving the second indication information includes: receiving a second request message for deleting the session of the second UE sent by the SMF, where the second request message carries a status value of the N4 link with a value of the third preset value.

15. The service handover method according to claim 14, wherein, after receiving the second request message for deleting the session of the second UE sent by the SMF, the method further includes: deleting the session of the second UE.

16. The service handover method according to claim 13, wherein, the modifying the status value of the N4 link and the UPF priority value according to the second indication information includes: modifying the status value of the N4 link to the third preset value and modifying the UPF priority value to the fourth preset value according to the second indication information, where the third preset value is used to indicate that the N4 link between the SMF and the second UPF is not disconnected, and the fourth preset value is used to indicate that the UPF carrying the current bearer service is the second UPF.

17. The service handover method according to claim 13, wherein, after receiving the second indication information, the method further includes: after the second UE goes online again, sending the status value of the N4 link and the UPF priority value modified most recently to the SMF, so that the SMF sets the second UPF to carry the service of the second UE according to the status value of the N4 link and the UPF priority value modified most recently.

18. The service handover method according to claim 17, wherein, Sending the status value of the N4 link with the most recent modification and the UPF priority value to the SMF includes: Receiving a second policy control request message sent by the SMF; Sending a second policy and charging control rule to the SMF, where the second policy and charging control rule includes the status value of the N4 link with a value of a third preset value, and the UPF priority value with a value of a fourth preset value. The third preset value is used to indicate that the N4 link between the SMF and the second UPF is not disconnected, and the fourth preset value is used to indicate that the UPF carrying the current service is the second UPF.

19. A service switching device Characterized in that Applied to a session management function network element SMF, the device includes: A first sending module, configured to send a first indication message to a policy control function network element PCF when it is detected that a first user plane function network element UPF carrying the current service fails. The first indication message is used to indicate that the N4 link between the SMF and the first user plane function network element UPF is disconnected, and to indicate that the PCF modifies the pre-recorded status value of the N4 link; A first receiving module, configured to receive the modified status value of the N4 link and the pre-recorded UPF priority value sent by the PCF, where the UPF priority value is used to indicate the UPF carrying the current service; A first switching module, configured to switch the service carried by the first user plane function network element UPF to the second UPF according to the modified status value of the N4 link and the pre-recorded UPF priority value; Wherein, the first indication message includes the status value of the N4 link with a value of a first preset value, and the first preset value is used to indicate that the N4 link between the SMF and the first user plane function network element UPF is disconnected; Wherein, the first sending module, when detecting that the first user plane function network element UPF carrying the current service fails, is configured to send a first indication message to the policy control function network element PCF, including: Sending a first request message to delete the session of the first terminal device UE to the PCF, where the first terminal device UE is one of the UEs to which the service carried on the first user plane function network element UPF belongs, and the first request message carries the status value of the N4 link with a value of the first preset value.

20. A service switching device Characterized in that Applied to a policy control function network element PCF, the device includes: A second receiving module, configured to receive a first indication message sent by a session management function network element SMF when a first user plane function network element UPF carrying the current service fails. The first indication message is used to indicate that the N4 link between the SMF and the first user plane function network element UPF is disconnected; A first modification module, configured to modify the pre-recorded status value of the N4 link according to the first indication message A second sending module, configured to send the modified status value of the N4 link and a pre-recorded UPF priority value to the SMF, so that the SMF switches the service carried by the first user plane function network element UPF to the second UPF according to the modified status value of the N4 link and the pre-recorded UPF priority value, where the UPF priority value is used to indicate the UPF carrying the current service. Wherein, the first indication information includes the status value of the N4 link with a first preset value, and the first preset value is used to indicate that the N4 link between the SMF and the first user plane function network element UPF is disconnected. Wherein, the process of the second receiving module receiving the first indication information sent by the session management function network element SMF when the first user plane function network element UPF carrying the current service fails includes: Receiving a first request message for deleting the session of the first terminal device UE sent by the SMF, where the first terminal device UE is one of the UEs to which the service carried on the first user plane function network element UPF belongs, and the first request message carries the status value of the N4 link with the first preset value.

21. A network device Characterized in that It includes a memory, a transceiver, and a processor: The memory is used to store computer programs; The transceiver is used to send and receive data under the control of the processor; the processor is used to read the computer program in the memory and execute the service switching method according to any one of claims 1 to 9, or execute the service switching method according to any one of claims 10 to 18.

22. A processor-readable storage medium Characterized in that The processor-readable storage medium stores a computer program, and the computer program is used to cause the processor to execute the service switching method according to any one of claims 1 to 9, or execute the service switching method according to any one of claims 10 to 18.

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