CN112867039B

CN112867039B - User plane network element fault processing method and device

Info

Publication number: CN112867039B
Application number: CN201911194071.9A
Authority: CN
Inventors: 王高亮
Original assignee: Datang Mobile Communications Equipment Co Ltd
Current assignee: Datang Mobile Communications Equipment Co Ltd
Priority date: 2019-11-28
Filing date: 2019-11-28
Publication date: 2022-04-05
Anticipated expiration: 2039-11-28
Also published as: CN112867039A

Abstract

The embodiment of the application provides a user plane network element fault processing method, wherein a user plane network element UPF and a control plane network element SMF are communicated, the UPF comprises a protocol data unit PDU session and a UPF function type, and the method comprises the following steps: presetting a PDU session recovery strategy; acquiring the session type of the protocol data unit PDU session; when the SMF judges that the UPF fails, determining the fault type of the failed UPF; determining a target PDU session recovery strategy corresponding to the failure UPF according to the PDU session type and the UPF function type; and recovering the PDU session by adopting the target PDU session recovery strategy. And the method realizes the fine processing of adopting different PDU session strategies for different fault types, and further ensures that the service influenced by the UPF fault is recovered efficiently.

Description

User plane network element fault processing method and device

Technical Field

The present invention relates to the field of communications technologies, and in particular, to a method and an apparatus for processing a user plane network element fault.

Background

In view of the demand of the future fifth generation mobile communication system (5G) for diversified services, when a User Equipment (UE) accesses a network, a User Plane Function (UPF) needs to be controlled by an SMF (e.g., a Session Management Function) to establish a service channel to carry the UE service.

However, in the process of providing the service forwarding service for the UE, the UPF may cause a condition that the service is not available as a whole or a part of the service entity is unavailable due to reasons such as application abnormality, link failure, power failure, etc., for example, the link between the SMF and the UPF is abnormal or the UPF fails, so that the UE service cannot operate normally.

The current UPF failure recovery mechanism mainly considers recovery of network element failure from the perspective of the whole network element. For example, when the UPF overall fault is recovered, only the UPF restart is considered to reconstruct the session, but for time-sensitive service sessions (such as virtual reality, unmanned services, and the like), the recovery after the UPF fault restart is useless, different types of sessions cannot be differentially processed, and the requirement of differentiation of different types of services of the UE on service continuity cannot be met; in addition, the condition of local failure of the existing network element to the network element is usually to directly replace the UPF, for example, the UPF has no recovery mechanism when part of the service session is affected due to internal reasons of the UPF.

Disclosure of Invention

In view of the above problems, embodiments of the present application are proposed to provide a method and apparatus for handling a user plane network element failure, which overcome the above problems or at least partially solve the above problems.

In order to solve the above problem, an embodiment of the present invention discloses a method for processing a user plane network element fault, which is characterized in that a user plane network element UPF communicates with a control plane network element SMF, the UPF includes a protocol data unit PDU session and a UPF function type, and the method includes:

presetting a PDU session recovery strategy;

acquiring the session type of the protocol data unit PDU session;

when the SMF judges that the UPF fails, determining the fault type of the failed UPF;

determining a target PDU session recovery strategy corresponding to the failure UPF according to the PDU session type and the UPF function type;

recovering the PDU session by adopting the target PDU session recovery strategy;

wherein the PDU session types include a Session Service Continuity (SSC) 1 pattern, an SSC2 pattern, and an SSC3 pattern; the UPF function types comprise a service anchor point PSA and an intermediate user plane network element I-UPF.

Optionally, the step of presetting the PDU session recovery policy includes:

pre-configuring a plurality of PDU session recovery strategies in the SMF;

the PDU conversation recovery strategies comprise restart UPF, reselection UPF, priority restart UPF and priority reselection UPF.

Optionally, the SMF is configured to receive heartbeat information sent by the UPF, where the heartbeat information includes a recovery timestamp, and the failure type of the UPF includes a link failure, an overall UPF failure, and an internal UPF failure, and when the SMF determines that the UPF fails, the step of determining the failure type of the failed UPF includes:

when the SMF judges that the UPF has the fault, if the SMF does not receive heartbeat information sent by the UPF within the time exceeding a preset threshold value and the recovery timestamp is unchanged when the SMF and the UPF are recovered in communication, determining that the fault type of the fault UPF is the link fault;

when the SMF judges that the UPF has a fault, if the SMF does not receive heartbeat information sent by the UPF within the time exceeding a preset threshold value and the recovery timestamp is changed when the SMF and the UPF are recovered in communication, determining that the fault type of the UPF has the fault as the UPF integral fault;

and when the SMF judges that the UPF fails, if part of PDU sessions in the UPF are unavailable, determining that the failure type of the failed UPF is an UPF internal failure.

Optionally, when it is determined that the failure type of the failed UPF is the link failure, the step of determining, according to the PDU session type and the UPF function type, a target PDU session recovery policy corresponding to the failed UPF includes:

when the PDU session type is the SSC1 mode, if the UPF function type is the PSA, determining that a corresponding target PDU session recovery strategy is a restart UPF;

when the PDU session type is the SSC2 mode, if the UPF function type is the PSA, determining that a corresponding target PDU session recovery strategy is a reselection UPF;

when the PDU session type is the SSC3 mode, if the UPF function type is the PSA, determining that a corresponding target PDU session recovery strategy is a priority reselection UPF;

and when the UPF function type is the I-UPF, determining that the corresponding target PDU session recovery strategy is a priority UPF restart or a reselection UPF.

Optionally, when it is determined that the failure type of the failed UPF is the overall failure of the UPF, the step of determining, according to the PDU session type and the UPF function type, a target PDU session recovery policy corresponding to the failed UPF includes:

if the PDU session type is the SSC1 mode and the UPF function type is the PSA or I-UPF, determining that a corresponding target PDU session recovery policy is a restart UPF;

if the PDU session type is the SSC2 mode or the SSC3 mode, determining that a corresponding target PDU session recovery policy is a reselected UPF.

Optionally, if the target PDU session recovery policy is a restart UPF, the step of recovering the PDU session using the target PDU session recovery policy includes:

setting a communication failure recovery timer CFT and restarting the UPF;

when the CFT is not expired and the UPF has restarted, the PDU session is resumed on the UPF.

Optionally, if the target PDU session recovery policy is a priority restart UPF, the step of recovering the PDU session by using the target PDU session recovery policy further includes:

when the recovery of the PDU session on the UPF fails, reselecting another UPF to recover the PDU session.

And when the CFT is over time, determining that the session recovery fails, and releasing the PDU session.

Optionally, if the target PDU session recovery policy is a re-selection UPF, the step of recovering the PDU session by using the target PDU session recovery policy further includes:

reselecting another UPF to recover the PDU session.

Optionally, if the target PDU session recovery policy is a priority reselection UPF, the step of recovering the PDU session by using the target PDU session recovery policy further includes:

and when the PDU session is failed to be recovered by reselecting another UPF, restarting the original UPF and recovering the PDU session.

Optionally, the method further comprises:

deleting the released PDU session during the link failure.

Optionally, when it is determined that the failure type of the failed UPF is an internal failure of the UPF, before the step of determining, according to the PDU session type and the UPF function type, a target PDU session recovery policy corresponding to the failed UPF, the method further includes:

acquiring a failure PDU session list generated by the UPF; wherein the failure PDU session list is used for indicating a failure PDU session, and the SMF further includes a session type of the failure PDU session.

Optionally, the step of determining a target PDU session recovery policy corresponding to the failed UPF according to the PDU session type and the UPF function type includes:

when the failure PDU session type is the SSC1 mode, if the UPF function type is the PSA, determining that a corresponding target PDU session recovery strategy is a restart UPF;

when the failure PDU session type is the SSC2 mode, if the UPF function type is the PSA, determining that the corresponding target PDU session recovery strategy is a reselection UPF;

when the failure PDU session type is the SSC3 mode, if the UPF function type is the PSA, determining that the corresponding target PDU session recovery strategy is a priority reselection UPF;

Optionally, if the target PDU session recovery policy is a restart UPF, the step of recovering the PDU session by using the target PDU session recovery policy further includes:

the UPF receives a failure PDU session list and recovery time requirement information sent by the SMF;

the UPF sets a PDU session recovery timer PRT according to the session recovery time requirement information;

restarting the UPF to recover the failed PDU session;

the UPF sends a session recovery result to the SMF;

wherein the session recovery result includes a failed PDU session list in which the PRT is not expired and the failed PDU session is recovered, or the session recovery fails.

Optionally, after the step of sending the session recovery result to the SMF, if the PDU session recovery policy is a restart priority UPF, the step of adopting the PDU session recovery policy, and recovering the PDU session further includes:

the SMF reselects another UPF to recover the failed PDU session.

reselecting another UPF to recover the failed PDU session.

Optionally, after reselecting another UPF to recover the failed PDU session, if receiving information that the partial failure of the UPF sent by the UPF has been recovered and the target PDU session recovery policy is a priority reselected UPF, the step of recovering the PDU session by using the target PDU session recovery policy further includes:

and restarting the UPF to recover the failure PDU session.

Optionally, the method further comprises:

otherwise, determining that the recovery of the failed PDU session fails, and releasing the failed PDU session.

The embodiment of the present application further provides a device for handling a failure of a user plane network element, where a user plane network element UPF communicates with a control plane network element SMF, the UPF includes a protocol data unit PDU session and a UPF function type, and the device includes:

the PDU conversation recovery strategy presetting module is used for presetting a PDU conversation recovery strategy;

a PDU session type acquisition module for acquiring the session type of the PDU session;

a UPF fault type determining module, configured to determine a fault type of a faulty UPF when the SMF determines that the UPF is faulty;

a target PDU session recovery strategy determining module, configured to determine a target PDU session recovery strategy corresponding to the faulty UPF according to the PDU session type and the UPF function type;

a target PDU session recovery strategy adopting module, configured to adopt the target PDU session recovery strategy to recover the PDU session;

Optionally, the PDU session recovery policy presetting module includes:

a PDU session recovery strategy presetting submodule for presetting a plurality of PDU session recovery strategies in the SMF;

Optionally, the SMF is configured to receive heartbeat information sent by the UPF, where the heartbeat information includes a recovery timestamp, and the failure type of the UPF includes a link failure, an overall UPF failure, and an internal UPF failure, and the UPF failure type determining module includes:

a link failure determining sub-module, configured to, when the SMF determines that the UPF fails, determine that a failure type of the failed UPF is the link failure if the SMF cannot receive heartbeat information sent by the UPF and exceeds a preset threshold and the recovery timestamp is unchanged when communication between the SMF and the UPF is recovered;

a UPF overall fault determining sub-module, configured to determine, when the SMF determines that the UPF has a fault, that the fault type of the faulty UPF is the UPF overall fault if the SMF cannot receive heartbeat information sent by the UPF and the recovery timestamp changes when communication between the SMF and the UPF is recovered and the SMF cannot receive heartbeat information sent by the UPF and the recovery timestamp changes;

and the UPF internal fault judgment sub-module is used for determining that the fault type of the fault UPF is the UPF internal fault if part of PDU sessions in the UPF are unavailable when the SMF judges that the UPF is in fault.

Optionally, when determining that the failure type of the failed UPF is the link failure, the target PDU session recovery policy determining module includes:

a first target PDU session recovery policy determining sub-module, configured to determine that a corresponding target PDU session recovery policy is a restart UPF if the UPF function type is the PSA when the failed PDU session type is the SSC1 mode;

a second target PDU session recovery policy determining sub-module, configured to determine that the corresponding target PDU session recovery policy is a reselected UPF if the UPF function type is the PSA when the failed PDU session type is the SSC2 mode;

a third target PDU session recovery policy determining sub-module, configured to determine that the corresponding target PDU session recovery policy is a priority reselection UPF if the UPF function type is the PSA when the failed PDU session type is the SSC3 mode;

and the fourth target PDU session recovery strategy determining sub-module is used for determining that the corresponding target PDU session recovery strategy is a priority UPF or a reselection UPF when the UPF function type is the I-UPF.

Optionally, when it is determined that the failure type of the failed UPF is the overall UPF failure, the target PDU session recovery policy determining module further includes:

a fifth target PDU session recovery policy determining sub-module, configured to determine that the corresponding target PDU session recovery policy is a restart UPF if the PDU session type is the SSC1 mode and the UPF function type is the PSA or I-UPF;

a sixth target PDU session recovery policy determining sub-module, configured to determine that a corresponding target PDU session recovery policy is a re-selection UPF if the PDU session type is the SSC2 mode or the SSC3 mode.

Optionally, if the target PDU session recovery policy is a restart UPF, the target PDU session recovery policy applying module includes:

the CFI timing submodule is used for setting a communication failure recovery timer CFT and restarting the UPF;

a first PDU session recovery sub-module for recovering the PDU session on the UPF when the CFT is not expired and the UPF has restarted.

Optionally, if the target PDU session recovery policy is a restart priority UPF, the target PDU session recovery policy applying module further includes:

a first UPF reselection sub-module, configured to reselect another UPF to recover the PDU session when recovery of the PDU session on the UPF fails.

And the PDU session release submodule is used for determining that the session recovery fails when the CFT is over time and releasing the PDU session.

Optionally, if the target PDU session recovery policy is a re-selection UPF, the target PDU session recovery policy applying module further includes:

and the second UPF reselection submodule is used for reselecting another UPF to recover the PDU session.

Optionally, if the target PDU session recovery policy is a preferred reselection UPF, the target PDU session recovery policy applying module further includes:

and the UPF restarting sub-module is used for restarting the original UPF and recovering the PDU session when the another UPF fails to recover the PDU session.

Optionally, the apparatus further comprises:

and the PDU session deleting submodule is used for deleting the released PDU session during the link failure.

Optionally, when the failure type of the failed UPF is determined to be an UPF internal failure, the apparatus further includes:

and the failure PDU session list acquisition module is used for acquiring the failure PDU session list generated by the UPF. Wherein the failure PDU session list is used for indicating a failure PDU session, and the SMF further includes a session type of the failure PDU session.

Optionally, the target PDU session recovery policy determining module includes:

a seventh target PDU session recovery policy determining sub-module, configured to determine that the corresponding target PDU session recovery policy is a restart UPF if the UPF function type is the PSA when the failed PDU session type is the SSC1 mode;

an eighth target PDU session recovery policy determining sub-module, configured to determine that the corresponding target PDU session recovery policy is a reselected UPF if the UPF function type is the PSA when the failed PDU session type is the SSC2 mode;

a ninth target PDU session recovery policy determining sub-module, configured to determine that the corresponding target PDU session recovery policy is a priority reselection UPF if the UPF function type is the PSA when the failed PDU session type is the SSC3 mode;

and the tenth target PDU session recovery strategy determining sub-module is used for determining that the corresponding target PDU session recovery strategy is a priority UPF or a reselection UPF when the UPF function type is the I-UPF.

Optionally, if the target PDU session recovery policy is a restart UPF, the target PDU session recovery policy applying module further includes:

a recovery time information receiving submodule, configured to receive a failure PDU session list and recovery time requirement information sent by the SMF;

a PDU session recovery timing setting submodule for setting a PDU session recovery timer PRT according to the session recovery time requirement information;

a UPF restart sub-module, configured to restart the UPF to recover the failed PDU session;

a recovery result sending module, configured to send a session recovery result to the SMF;

Optionally, after the step of sending the session recovery result to the SMF, if the PDU session recovery policy is a restart priority UPF, the target PDU session recovery policy applying module further includes:

a first UPF reselection sub-module for reselecting another UPF to recover the failed PDU session.

Optionally, if the target PDU session recovery policy is a reselected UPF, the target PDU session recovery policy applying module further includes:

and the second UPF reselection submodule is used for reselecting another UPF to recover the failed PDU session.

Optionally, after reselecting another UPF to recover the failed PDU session, if receiving information that the partial failure of the UPF sent by the UPF has been recovered and the target PDU session recovery policy is a priority reselected UPF, the target PDU session recovery policy applying module further includes:

and the UPF restarting submodule is used for restarting the UPF to recover the failed PDU session.

Optionally, the apparatus further comprises:

and the failure PDU session release submodule is used for determining that the failure PDU session is failed to recover and releasing the failure PDU session.

The embodiment of the application has the following advantages:

in the embodiment of the application, a user plane network element UPF and a control plane network element SMF are communicated, a PDU session recovery strategy can be preset and used for carrying out corresponding detailed processing on different faults of the user plane network element UPF, when the control plane network element SMF judges that the user plane network element has a fault, the fault type of the fault UPF is determined, a target PDU session recovery strategy corresponding to the fault UPF is determined according to the PDU session type and the functional type of the UPF, the PDU session is recovered by adopting the target PDU session recovery strategy, so that different PDU session strategies are adopted according to different fault types, and the efficient recovery of services influenced by the UPF fault is ensured.

Drawings

Fig. 1 is a flowchart of a first embodiment of a method for processing a user plane network element fault according to the present invention;

fig. 2 is a flowchart of the steps of a second embodiment of a method for processing a fault of a user plane network element according to the present invention;

fig. 3 is a block diagram of an embodiment of a user plane network element fault handling apparatus according to the present invention;

fig. 4 is a schematic diagram of a fault location when a link fault or an overall fault occurs in a method for processing a user plane network element fault according to the present invention;

fig. 5 is a schematic diagram of a fault location of an internal fault of a user plane network element in the method for processing a fault of a user plane network element according to the present invention;

fig. 6 is a schematic diagram of a session recovery strategy when a link failure or an overall failure occurs in a user plane network element failure handling method according to the present invention;

fig. 7 is a schematic diagram of another session recovery strategy when a link fails or an overall failure occurs in a user plane network element failure handling method according to the present invention;

fig. 8 is a schematic diagram of a session recovery policy when a user plane network element internal failure occurs in a user plane network element failure processing method according to the present invention;

fig. 9 is a schematic diagram of another session recovery policy when the user plane network element internal failure occurs in the method for processing the user plane network element failure according to the present invention.

Detailed Description

In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in further detail below.

One of the core concepts of the embodiment of the application is that for a user plane network element fault, the user plane network element fault type is subdivided through a control plane network element, different recovery strategies are provided according to different fault types, and service session continuity is guaranteed under the condition of the user plane network element fault; and the user plane network element resources are fully utilized to ensure that the service session influenced by the user plane network element fault can be efficiently recovered.

Referring to fig. 1, a flowchart illustrating steps of an embodiment of a method for handling a failure of a user plane network element according to the present invention is shown, where a user plane network element UPF communicates with a control plane network element SMF, and the UPF includes a protocol data unit PDU session and a UPF function type, and specifically may include the following steps:

step 101, presetting a PDU session recovery strategy;

102, acquiring the session type of the protocol data unit PDU session;

103, when the SMF judges that the UPF has a fault, determining the fault type of the fault UPF;

104, determining a target PDU session recovery strategy corresponding to the failure UPF according to the PDU session type and the UPF function type;

and 105, recovering the PDU session by adopting the target PDU session recovery strategy.

In the embodiment of the application, a PDU session recovery strategy can be preset in the SMF, after the SMF obtains the session type of a protocol data unit PDU session, the UPF is judged to be a link failure or an UPF overall failure, a corresponding target PDU session recovery strategy is determined according to the PDU session type and the UPF function type, and the PDU session is recovered by adopting the target PDU session recovery strategy. Therefore, different failures of the PDU conversation can be subdivided, and an adaptive PDU conversation recovery strategy can be provided. And further, the service session continuity can be guaranteed under the condition of the failure of the user plane network element.

The embodiment of the application can be applied to a 5GC network element, wherein a User plane network element (such as UPF) generally provides a service forwarding service for UE (User Equipment), and the service experience of the UE is directly influenced by the UPF related fault. When the UE accesses the network, a control plane network element (e.g., SMF) needs to control a user plane network element (e.g., UPF), and a service channel is established on the UPF to carry the UE service. Specifically, the control plane network element selects a user plane network element that can meet the UE service requirement from suitable user plane network elements, and the user plane network element is used as an entity for processing the user plane service, so as to implement functions of continuing and forwarding the UE service in the core network.

The user plane network element (e.g. UPF) is inevitable in providing the service forwarding service for the UE, and may cause the situation that its service is not available as a whole or part of the service entity is not available due to some reasons (e.g. application anomaly, link failure, power failure, etc.). If the selected UPF fails, the UE service on the selected UPF cannot be performed normally. At this time, the network needs to take certain measures to recover the service, so as to ensure the continuity of the UE service.

In a 5GC network element, faults that frequently occur in the UPF are communication abnormality and local faults, and the following describes the embodiments of the present application in a scenario where the UPF is in communication abnormality and local fault, respectively.

Referring to fig. 2, a flowchart illustrating steps of another embodiment of a method for handling a user plane network element failure according to the present invention is shown. The method may comprise the steps of:

step 201, a PDU session recovery policy is preset.

The method is applied to the embodiment of the application, a plurality of PDU session recovery strategies can be preset in the SMF, the PDU session recovery strategies at least comprise session service continuity session types of a plurality of user services, user plane network element function types and corresponding PDU session recovery strategies, and the PDU session recovery strategies are used for maintaining the corresponding relations among the session types, the UPF function types and the corresponding PDU session recovery strategies.

In the embodiment of the present application, step 201 may include the following sub-steps:

a substep 2011 of pre-configuring a plurality of PDU session recovery policies in the SMF.

Wherein the plurality of PDU session recovery policies include: restarting the UPF and reselecting the UPF; restarting UPF preferentially and reselecting UPF preferentially.

In a specific implementation, the various PDU session recovery policies may be configured in the following form:

m1: and restarting the UPF, starting a communication failure recovery timer CFT and restarting the UPF, and selecting to execute the selected session reconfiguration processing on the CFT if the CFT is not expired and the failure UPF is restarted.

M2: reselecting the UPF, reselecting a new UPF, and recovering the selected PDU session on the new UPF.

M3: firstly, starting a communication failure recovery timer CFT and restarting the UPF, and if the CFT is not overdue and the failure UPF is restarted, selecting to execute the selected PDU session reconfiguration processing on the CFT; and if the CFT is over-time, the selected PDU session is regarded as a failure UPF unrecoverable session, a new UPF is reselected, and the selected PDU session is recovered on the new UPF.

M4: reselecting the UPF preferentially, firstly reselecting a new UPF, recovering the selected PDU session on the new UPF, and simultaneously detecting the running state of the original UPF; if the original UPF has been restarted and the recovery of the selected PDU session on the new UPF fails, the selected PDU session is recovered on the original UPF.

Step 202, obtaining the session type of the protocol data unit PDU session.

In a specific implementation, the PDU session type on the UPF may be obtained by the SMF, or the UPF may report the PDU session type of the UE service to the SMF at regular time.

And 203, when the SMF judges that the UPF has the fault, determining the fault type of the fault UPF.

In a specific implementation, there are various types of failures related to the user plane network element, such as a link between the user plane and the control plane being abnormal, a user plane network element interface being failed, a user plane network element service processing entity being failed, and the like. The influence of these faults on the service is different, and the corresponding processing mechanisms are also different.

According to the scheme, the coping strategies are respectively given according to the fault conditions of different levels of the user plane network elements, so that the requirement of UE service continuity can be met to the maximum extent.

In this embodiment of the present application, the SMF is configured to receive heartbeat information sent by the UPF, where the heartbeat information includes a recovery timestamp; the fault type of the UPF may be divided into SMF and UPF communication anomalies, or a UPF internal fault, and specifically, the SMF and UPF communication anomalies may be subdivided into a link fault and a UPF overall fault.

In a specific implementation, the method for the SMF to determine that the communication between the UPF and the SMF is abnormal may be multiple, for example, whether the heartbeat message between the UPF and the SMF is lost more than a threshold number of times, and if the heartbeat message is lost more than the threshold number of times, the communication between the UPF and the SMF is determined to be abnormal.

In terms of user service experience, during abnormal communication between the UPF and the SMF, unless other human intervention occurs, the UPF cannot communicate with the SMF, and the normal processing state of the existing service should be maintained, so as to ensure that user plane service forwarding is not affected as much as possible.

In the embodiment of the present application, step 203 may include the following sub-steps:

substep 2031, when the SMF determines that the UPF has a failure, determining that the failure type of the failed UPF is the link failure if the SMF does not receive heartbeat information sent by the UPF within a time period exceeding a preset threshold value and the recovery timestamp is not changed when communication between the SMF and the UPF is recovered.

Referring to fig. 4, in this embodiment of the present application, the SMF may periodically acquire a session type of the PDU session, or periodically report, by the UPF, a session type of the PDU session carried. When the SMF cannot know the session type of the PDU session, determining that the SMF and the UPF are abnormal in communication.

Further, the UPF sends heartbeat information to the SMF at regular time, and by presetting a time threshold value on the SMF, when the SMF does not receive the heartbeat information of the UPF within a range exceeding the time threshold value, the fact that communication abnormity occurs between the SMF and the UPF can be judged. And when the communication is recovered, if the recovery timestamp is not changed, the specific type of the communication abnormality can be further determined to be a link failure.

Optionally, the recovery timestamp of the UPF may be sent to the SMF through heartbeat information between the SMF and the UPF, or may be sent to the SMF by being carried by the UPF in a process of establishing an association between the SMF and the UPF.

Substep 2032, when the SMF determines that the UPF fails, if the SMF does not receive heartbeat information sent by the UPF within a time period exceeding a preset threshold value and the recovery timestamp changes when communication between the SMF and the UPF is recovered, determining that the failure type of the failed UPF is the UPF overall failure;

in this embodiment of the present application, the occurrence of the communication abnormality between the SMF and the UPF further includes that when the communication between the SMF and the UPF is recovered, if the recovery timestamp is not changed, the specific type of the communication abnormality may be further determined to be an UPF overall fault, that is, the fault type of the UPF is determined to be the UPF overall fault.

Substep 2033, when the SMF determines that the UPF fails, determining that the failure type of the failed UPF is an UPF internal failure if part of the PDU sessions in the UPF are unavailable.

Referring to fig. 4, in the embodiment of the present application, the communication link between the SMF and the UPF is normal, but the UPF may render the UPF partial PDU session unavailable due to internal individual service node anomalies, or N3/N9/N6 link anomalies. At this time, the fault type of the faulty UPF can be judged to be an UPF internal fault.

When the fault type of the faulty UPF is judged to be an UPF internal fault, since the communication between the SMF and the UPF is not interrupted, and the communication can be reported to the SMF according to the UPF report information, the sub-step 2032 may further include the following sub-steps:

substep 20321, obtaining a failure PDU session list generated by the UPF; wherein the failure PDU session list is used for indicating a failure PDU session, and the SMF further includes a session type of the failure PDU session.

In a specific implementation, when the SMF acquires the session type of the failed PDU, a decision may be made according to the session type of the failed PDU session, so that it may be determined that the manner of recovering the PDU session is to perform a session by the SMF-dominated UPF, or to recover by the UPF itself.

Therefore, the available resources of the UPF of the service plane network element are fully utilized, and the service influenced by the UPF fault is ensured to be efficiently recovered.

And 204, determining a corresponding target PDU session recovery strategy according to the PDU session type and the UPF function type.

In the embodiment of the present application, the PDU session type includes a session service continuity SSC1 pattern, SSC2 pattern and SSC3 pattern.

As for the UE Service characteristics, the UE Service has three types of Session and Service Continuity (SSC) modes, which are: SSC1 pattern, SSC2 pattern, SSC3 pattern. SSC1 means that the PDU (protocol data unit) session anchor point of UE service is always kept unchanged after the UE service session is established, and the IP continuity is kept; the SSC2 means that the original PDU session is deleted firstly and then another PDU session is created to provide the UE service in the process of the UE service due to service requirements or other factors; the SSC3 refers to UE service provided by adding another session anchor for the current PDU session before releasing the session anchor due to service requirements or other factors while the UE service is in progress.

In the embodiment of the present application, the UPF function types include a service anchor point PSA and an intermediate user plane network element I-UPF.

The service anchor point PSA refers to an entity (device and module) capable of independently providing a certain service, and is a network element capable of receiving various switching type or permanent connection type telecommunication services.

The intermediate user plane network element I-UPF refers to a network element between the user plane network element UPF of the PDU session carrying the UE service and the user equipment UE, and is used for providing the transmission of the PDU session.

In this embodiment of the present application, when the failure type of the failed UPF is determined to be a link failure or an internal failure of the UPF, step 204 may include the following sub-steps:

substep 2041, if the PDU session type is the SSC1 mode and the UPF function type is the PSA, determining that the corresponding target PDU session recovery policy is a restart UPF;

substep 2042, if the PDU session type is the SSC2 mode and the UPF function type is the PSA, determining that the corresponding target PDU session recovery policy is a reselected UPF;

substep 2043, if the PDU session type is the SSC3 mode and the UPF function type is the PSA, determining that the corresponding target PDU session recovery policy is a priority reselection UPF;

and a substep 2044, determining the corresponding target PDU session recovery strategy to be a priority restart UPF or a reselection UPF if the UPF function type is the I-UPF.

For example, the PDU session recovery policy may be represented in a table form, as shown in table 1 below:

TABLE 1

Optionally, the PDU session recovery policy may further include network slice selection information SNSSAI and quality of service flow identification QFI of the PDU session.

A Network slice is understood to be a set of logical Network functions supporting communication service requirements of a specific usage scenario or business model, and is based on the implementation of a physical infrastructure to a service, and these logical Network functions can be regarded as a series of sub-functions (Network sub-functions) decomposed from Network functions (Network functions) under the EPC. Based on this, the network slice selection information SNSSAI can be understood as an identifier which is customized by the user according to the function of the network slice and reflects the PDU session continuity requirement.

The QFI is an identifier which can provide better service capability for specified network communication by utilizing various basic technologies; can provide the transmission quality service for the equipment supporting the QoS function; for a certain class of data flows, it can be given a certain level of transmission priority to identify its relative importance, and provide special transmission services for these data flows using various priority forwarding policies, congestion avoidance, etc. provided by the device.

The continuity requirement for the PDU session can be determined based on the network slice selection information SNSSAI;

in a specific implementation, network slice selection information SNSSAI of a PDU session may be obtained first, and the PDU session is determined to be in a high continuity requirement or a low continuity requirement according to the SNSSAI of the PDU session.

The priority requirement for the PDU session may be determined based on the quality of service flow identity QFI;

in a specific implementation, the qos flow identifier QFI of the PDU session may be obtained first, and the priority of the PDU session may be divided into a high priority or a low priority according to the QFI of the PDU session.

For example, the PDU session recovery policy may be represented in a table form, as shown in table 2 below:

TABLE 2

When the fault type of the faulty UPF is determined to be an overall UPF fault, step 204 may further include the following sub-steps:

sub-step X1, determining a corresponding target PDU session recovery policy to be a restart UPF if the PDU session type is the SSC1 mode and the UPF function type is the PSA or I-UPF;

sub-step X2, if the PDU session type is the SSC2 mode or the SSC3 mode, determining the corresponding target PDU session recovery policy to be reselection UPF.

In a particular implementation, a UPF overall session is not available due to an overall UPF failure. The session type corresponding to the PDU session is recorded in the SMF, and it can be known that the PDU session recovery policy is determined to be the restart UPF or the reselection UPF directly according to the PDU session type and the functional type of the UPF, which is not described herein again.

And step 205, adopting the target PDU session recovery strategy to recover the PDU session.

In the embodiment of the application, the PDU session can be recovered according to the determined target PDU session recovery policy.

Optionally, step 205 may further comprise the sub-steps of:

as shown in fig. 6, when it is determined that the failure type of the failed UPF is the link failure or the overall failure of the UPF, and the PDU session recovery policy is a restart UPF, step 205 may further include the following sub-steps:

substep 20511, setting a communication failure recovery timer CFT and restarting the UPF;

where the communication failure recovery timer CFT refers to a timer that can be started upon detection of a UPF and SMF link failure, the validity of the PSA for such sessions is maintained until the timer expires.

In a specific implementation, the timing length and whether the CFT timer is enabled or not may be determined by an operator according to factors such as the location of the UPF (e.g., PSA or I-UPF) and the PDU session characteristics of the bearer (e.g., quality of service indicator or network slice selection information).

Substep 20512, when the CFT is not expired and the UPF has restarted, resuming the PDU session on the UPF;

in a specific implementation, the effectiveness of the PSA is maintained during CFT timing since the CFT is not timed out and the UPF has restarted. Therefore, the PDU session can be directly established with the UE through the restarted UPF, and then the PDU session is recovered.

As shown in fig. 6, when the PDU session recovery policy is a priority restart UPF, step 205 may further include the following sub-steps:

a sub-step 20521 of reselecting another UPF to recover the PDU session when recovery of the PDU session on the UPF fails.

In a specific implementation, since the CFT is not expired but there is still a failure after the UPF restart, the PSA cannot be maintained, at which point the recovery of the PDU session may fail.

When the selected PDU session recovery policy is a priority restart UPF, since the SCC1 has a high requirement on session continuity, another UPF may be reselected, a PSA is established on the another UPF, and a PDU session is re-established with the UE, thereby recovering the PDU session.

And a substep 20524 of determining that the session recovery fails and releasing the PDU session when the CFT expires.

In the embodiment of the present application, when the CFT expires, the PSA cannot maintain its validity due to the influence of the session continuity PDU session on the PDU session. Therefore, whether the UPF is possible to restart successfully or fails, the SMF can determine that the PDU session is failed to recover, and then the PDU session is released.

The manner of releasing the PDU session can isolate the PSA of the PDU session through the SMF, so as to prevent the PSA from affecting other PDU sessions.

As shown in fig. 7, when it is determined that the failure type of the failed UPF is the SMF and UPF link failure or the UPF overall failure, and the PDU session recovery policy is a reselected UPF, step 205 may further include the following sub-steps:

sub-step 20531, reselecting another UPF to resume the PDU session.

In the embodiment of the application, the SMF can trigger the release of the current PDU session and inform the UE to reinitiate the new PDU session establishment, and the SMF reselects a new UPF to serve as the PSA for the UE service, thereby recovering the PDU session.

Alternatively, the SMF may trigger a new PSA setup, and the current PSA may be removed from the session after the service is switched to the PSA on the new UPF.

As shown in fig. 7, when the PDU session recovery policy is a priority reselection UPF, step 205 may further include the following sub-steps:

and a substep 20541, when the recovery of the PDU session by reselecting another UPF fails, restarting the original UPF and recovering the PDU session.

In the embodiment of the present application, it is possible that another reselected UPF also fails, and the PDU session cannot be recovered in time. Due to the continuity requirement of the PDU session, the SMF can also detect the running state of the UPF in real time, if the original UPF is restarted or the link failure is recovered, the SMF can establish the PSA in the restarted original UPF, reestablish the PDU session with the UE and further recover the PDU session. Optionally, based on the user experience, the UE of the PDU session may be informed in advance, and for the UE, some pre-protection processing may be performed, including but not limited to, creating another PDU session first and transferring the traffic to it, so as to minimize the impact on the session due to communication failure.

As shown in fig. 8, when it is determined that the failure type of the failed UPF is an internal failure of the UPF and the target PDU session recovery policy is a restart UPF, step 205 may specifically include the following sub-steps:

substep 20551, receiving the failure PDU session list and the recovery time requirement information sent by the SMF;

a substep 20552, setting a PDU session recovery timer PRT according to the session recovery time requirement information;

substep 20553 of restarting said UPF to recover said failed PDU session;

a sub-step 20554 of sending a session recovery result to the SMF;

wherein the session recovery result includes a result that the PRT is not expired and the failed PDU session is recovered, or a failed PDU session list in which session recovery fails.

As shown in fig. 8, after sending the session recovery result to the SMF, the method further includes:

sub-step 20555, when the PDU session recovery policy is a priority restart UPF, the step of recovering the failed PDU session by using the PDU session recovery policy further includes: reselecting another UPF to recover the failed PDU session.

As shown in fig. 9, when it is determined that the failure type of the failed UPF is an internal failure of the UPF and the target PDU session recovery policy is a reselected UPF, step 205 may further include the following sub-steps:

sub-step 20561, reselecting another UPF to recover the failed PDU session.

Sub-step 20562, after said reselecting another UPF to recover said failed PDU session, further comprises:

receiving UPF local fault recovered information sent by the UPF;

as shown in fig. 9, when the PDU session recovery policy is a priority reselection UPF, the step of recovering the failed PDU session by using the target PDU session recovery policy further includes:

and restarting the UPF to recover the failure PDU session.

And a substep 2057, otherwise, determining that the recovery of the failed PDU session fails, and releasing the failed PDU session.

In a specific implementation, due to a failure of a node of the UPF part, the recovery of the PDU session actively recovered by the UPF may fail. In order to prevent the UE from failing to perform service processing on the failed PDU session, the failed PDU session may be directly released, so that the UE may newly select a UPF bearer PDU session.

Optionally, in this embodiment of the present application, the method for processing a user plane network element fault may further include the following steps:

step 206, deleting the released PDU session during the link failure.

In the embodiment of the application, during the communication exception, the SMF releases the unrecoverable PDU session and the migrated PDU session, or isolates the PSA of the PDU session. Therefore, the SMF deletes the upper PDU session, and the UE is prevented from performing invalid service processing on the released PDU session.

Optionally, since the UPF is not restarted, if the UPF continues to maintain the original PDU session, the UE may not recognize the reselected UPF, which further affects service execution continuity, and thus user experience is reduced. Thus, a delete operation may be performed by the SMF for a session that has previously migrated out of this UPF, i.e., a session that is to be migrated from the affected UPF to the new UPF is purged from the former.

and step 207, when the SMF and the UPF are recovered, determining the restarting condition of the UPF according to whether the recovery time stamp is changed.

In a specific implementation, due to a failure of the UPF, communication abnormality with the control plane SMF is caused, and a full session (PFCP session) on the UPF is unavailable. The SMF needs to make decisions and dominate traffic restoration based on the UPF restart.

Step 207 may also include the following sub-steps:

step 2071, determining that the UPF is restarted if the recovery timestamp changes;

in this embodiment of the present application, if the recovery timestamp changes, it may be determined that the UPF is restarted and the communication between the SMF and the UPF is recovered. The SMF reconfigures the PDU session that needs to be recovered after the failed UPF restarts. For example, the SMF fails to migrate some PDU sessions on the affected UPF due to other reasons, such as resource limitation, service specificity, etc., and needs to recover the affected UPF after restarting.

For example, the recovery of PSA adapted to SSC1 type PDU sessions, or I-UPF for scenarios insensitive to traffic anomalies

Step 2072, if the recovery timestamp is not changed, determining that the UPF is not restarted.

In an embodiment of the present application, if the recovery timestamp is not changed, it may be determined that the UPF is not restarted and communication between the SMF and the UPF is not recovered. The PDU session of the scene sensitive to the service continuity, such as the PDU session of SSC2/SSC3 mode, can be recovered by the UPF reselection of the SMF.

According to the embodiment of the application, the user plane network element is subdivided in fault types by presetting the user plane network element recovery strategies of four categories, so that the service continuity guarantee matched with the user plane network element fault situation of different types of services can be ensured, the purpose of executing a refined recovery mechanism for the user plane network element is further achieved, and the user service experience is enhanced; in addition, the embodiment of the application can also carry out grading on the recovery mechanism of the user plane network element, and can effectively improve the timeliness of UPF fault recovery; by using the report of the UPF and the decision of the SMF, the purposes of fully utilizing the resources of the user plane network element and ensuring that the UPF service subjected to the fault can be efficiently recovered are achieved.

It should be noted that, for simplicity of description, the method embodiments are described as a series of acts or combination of acts, but those skilled in the art will recognize that the embodiments are not limited by the order of acts described, as some steps may occur in other orders or concurrently depending on the embodiments. Further, those skilled in the art will also appreciate that the embodiments described in the specification are presently preferred and that no particular act is required of the embodiments of the application.

Referring to fig. 3, a block diagram of a structure of an embodiment of a device for handling a failure of a user plane network element according to the present invention is shown, where a user plane network element UPF communicates with a control plane network element SMF, the UPF includes a protocol data unit PDU session and a UPF function type, and the device may specifically include:

a PDU session recovery policy presetting module 301, configured to preset a PDU session recovery policy;

a PDU session type obtaining module 302, configured to obtain a session type of the PDU session;

a UPF fault type determining module 303, configured to determine a fault type of a faulty UPF when the SMF determines that the UPF has a fault;

a target PDU session recovery policy determining module 304, configured to determine a target PDU session recovery policy corresponding to the faulty UPF according to the PDU session type and the UPF function type;

a target PDU session recovery policy applying module 305, configured to apply the target PDU session recovery policy to recover the PDU session;

Optionally, the PDU session recovery policy presetting module 301 includes:

Optionally, the SMF is configured to receive heartbeat information sent by the UPF, where the heartbeat information includes a recovery timestamp, and the failure type of the UPF includes a link failure, an overall UPF failure, and an internal UPF failure, and the UPF failure type determining module 303 includes:

Optionally, when determining that the failure type of the failed UPF is the link failure, the target PDU session recovery policy determining module 304 includes:

Optionally, when determining that the failure type of the failed UPF is the UPF overall failure, the target PDU session recovery policy determining module 304 further includes:

Optionally, if the target PDU session recovery policy is a restart UPF, the target PDU session recovery policy applying module 305 includes:

Optionally, if the target PDU session recovery policy is a priority restart UPF, the target PDU session recovery policy applying module 305 further includes:

Optionally, if the target PDU session recovery policy is a re-selection UPF, the target PDU session recovery policy applying module 305 further includes:

Optionally, if the target PDU session recovery policy is a preferred reselection UPF, the target PDU session recovery policy applying module 305 further includes:

Optionally, the apparatus further comprises:

Optionally, the target PDU session recovery policy determining module 304 includes:

Optionally, if the target PDU session recovery policy is a restart UPF, the target PDU session recovery policy applying module 305 further includes:

Optionally, after the step of sending the session recovery result to the SMF, if the PDU session recovery policy is a restart priority UPF, the target PDU session recovery policy applying module 305 further includes:

Optionally, if the target PDU session recovery policy is a reselected UPF, the target PDU session recovery policy applying module 305 further includes:

Optionally, after reselecting another UPF to recover the failed PDU session, if receiving partial failure recovered information of the UPF sent by the UPF and the target PDU session recovery policy is a priority reselected UPF, the target PDU session recovery policy applying module 305 further includes:

Optionally, the apparatus further comprises:

Optionally, the PDU session recovery policy presetting module 301 includes:

Optionally, the apparatus further comprises:

For the device embodiment, since it is basically similar to the method embodiment, the description is simple, and for the relevant points, refer to the partial description of the method embodiment.

The embodiments in the present specification are described in a progressive manner, each embodiment focuses on differences from other embodiments, and the same and similar parts among the embodiments are referred to each other.

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

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

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

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

While preferred embodiments of the present application have been described, additional variations and modifications of these embodiments may occur to those skilled in the art once they learn of the basic inventive concepts. Therefore, it is intended that the appended claims be interpreted as including the preferred embodiment and all such alterations and modifications as fall within the true scope of the embodiments of the application.

Finally, it should also be noted that, herein, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or terminal that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or terminal. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other like elements in a process, method, article, or terminal that comprises the element.

The method and the device for processing the user plane network element fault provided by the invention are introduced in detail, and a specific example is applied in the text to explain the principle and the implementation mode of the invention, and the description of the embodiment is only used for helping to understand the method and the core idea of the invention; meanwhile, for a person skilled in the art, according to the idea of the present invention, there may be variations in the specific embodiments and the application scope, and in summary, the content of the present specification should not be construed as a limitation to the present invention.

Claims

1. A method for processing user plane network element fault is characterized in that a user plane network element UPF and a control plane network element SMF are communicated, the UPF comprises a protocol data unit PDU session and a UPF function type, and the method comprises the following steps:

presetting a PDU session recovery strategy;

acquiring the session type of the protocol data unit PDU session;

2. The method of claim 1, wherein the step of presetting a PDU session recovery policy comprises:

pre-configuring a plurality of PDU session recovery strategies in the SMF;

the PDU session recovery strategies comprise a restart UPF, a reselection UPF, a priority restart UPF or a priority reselection UPF.

3. The method of claim 1, wherein the SMF is configured to receive heartbeat information sent by the UPF, wherein the heartbeat information includes a recovery timestamp, and wherein the failure type of the UPF includes a link failure, an UPF overall failure, and an UPF internal failure, and wherein the step of determining the failure type of the failed UPF when the SMF determines that the UPF is failed comprises:

4. The method according to claim 3, wherein when determining that the failure type of the failed UPF is the link failure, the step of determining the target PDU session recovery policy corresponding to the failed UPF according to the PDU session type and the UPF function type comprises:

5. The method according to claim 3, wherein when determining that the failure type of the failed UPF is the UPF overall failure, the step of determining the target PDU session recovery policy corresponding to the failed UPF according to the PDU session type and the UPF function type comprises:

6. The method according to claim 4 or 5, wherein if the target PDU session recovery policy is UPF restart, the step of recovering the PDU session using the target PDU session recovery policy comprises:

setting a communication failure recovery timer CFT and restarting the UPF;

7. The method of claim 6, wherein if the target PDU session recovery policy is UPF (upstream restart priority), the step of recovering the PDU session using the target PDU session recovery policy further comprises:

when the PDU session is failed to be recovered on the UPF, reselecting another UPF to recover the PDU session;

8. The method according to claim 4 or 5, wherein if the target PDU session recovery policy is a reselected UPF, the step of recovering the PDU session using the target PDU session recovery policy further comprises:

reselecting another UPF to recover the PDU session.

9. The method of claim 8, wherein if the target PDU session recovery policy is a priority reselection UPF, the step of recovering the PDU session using the target PDU session recovery policy further comprises:

10. The method of claim 7, further comprising:

deleting the released PDU session during the link failure.

11. The method according to claim 3, wherein when determining that the failure type of the failed UPF is an UPF internal failure, before the step of determining a target PDU session recovery policy corresponding to the failed UPF according to the PDU session type and the UPF function type, the method further comprises:

12. The method according to claim 11, wherein the step of determining the target PDU session recovery policy corresponding to the failed UPF according to the PDU session type and the UPF function type comprises:

13. The method of claim 12, wherein if the target PDU session recovery policy is restart UPF, the step of recovering the PDU session using the target PDU session recovery policy further comprises:

restarting the UPF to recover the failed PDU session;

the UPF sends a session recovery result to the SMF;

14. The method of claim 13, wherein after the step of sending the session recovery result to the SMF, if the PDU session recovery policy is a priority restart (UPF), the step of adopting the PDU session recovery policy, and the step of recovering the PDU session further comprises:

the SMF reselects another UPF to recover the failed PDU session.

15. The method of claim 12, wherein if the target PDU session recovery policy is re-selection UPF, the employing the target PDU session recovery policy, and the step of recovering the PDU session further comprises:

reselecting another UPF to recover the failed PDU session.

16. The method according to claim 15, wherein after reselecting another UPF to recover the failed PDU session, if receiving partial failure recovery information of the UPF sent by the UPF and the target PDU session recovery policy is a priority reselection UPF, the employing the target PDU session recovery policy, the step of recovering the PDU session further comprises:

and restarting the UPF to recover the failure PDU session.

17. The method according to claim 14 or 16, characterized in that the method further comprises:

18. A user plane network element fault handling device is characterized in that a user plane network element UPF and a control plane network element SMF are communicated, the UPF comprises a Protocol Data Unit (PDU) session and a UPF function type, and the device comprises:

19. The apparatus of claim 18, wherein the PDU session recovery policy provisioning module comprises:

20. The apparatus of claim 18, wherein the SMF is configured to receive heartbeat information sent by the UPF, wherein the heartbeat information includes a recovery timestamp, wherein the failure types of the UPF include a link failure, an UPF overall failure, and an UPF internal failure, and wherein the UPF failure type determining module comprises:

and a UPF internal fault determining sub-module, configured to determine, when the SMF determines that the UPF fails, that the fault type of the failed UPF is an UPF internal fault if a part of PDU sessions in the UPF is unavailable.

21. The apparatus as claimed in claim 20, wherein when the failure type of the failed UPF is determined to be the link failure, the target PDU session recovery policy determination module comprises:

22. The apparatus according to claim 20, wherein when the failure type of the failed UPF is determined to be the UPF overall failure, the target PDU session recovery policy determination module further comprises:

23. The apparatus of claim 21 or 22, wherein if the target PDU session recovery policy is restart UPF, the target PDU session recovery policy applying module comprises:

24. The apparatus of claim 23, wherein if the target PDU session recovery policy is restart priority UPF, the target PDU session recovery policy applying module further comprises:

a first UPF reselection sub-module, configured to reselect another UPF to recover the PDU session when recovery of the PDU session on the UPF fails;

25. The apparatus according to claim 21 or 22, wherein if the target PDU session recovery policy is a reselected UPF, the target PDU session recovery policy applying module further comprises:

26. The apparatus of claim 25, wherein if the target PDU session recovery policy is a priority reselection UPF, the target PDU session recovery policy applying module further comprises:

27. The apparatus of claim 24, further comprising:

28. The apparatus according to claim 20, wherein when the failure type of the failed UPF is determined to be an UPF internal failure, the apparatus further comprises:

a failure PDU session list obtaining module, configured to obtain a failure PDU session list generated by the UPF, where the failure PDU session list is used to indicate a failure PDU session, and the SMF further includes a session type of the failure PDU session.

29. The apparatus of claim 28, wherein the target PDU session recovery policy determination module comprises:

30. The apparatus of claim 29, wherein if the target PDU session recovery policy is restart UPF, the target PDU session recovery policy applying module further comprises:

31. The apparatus of claim 30, wherein after the step of sending the session recovery result to the SMF, if the PDU session recovery policy is a priority restart (UPF), the target PDU session recovery policy applying module further comprises:

32. The apparatus of claim 29, wherein if the target PDU session recovery policy is reselected UPF, the target PDU session recovery policy applying module further comprises:

33. The apparatus of claim 32, wherein after reselecting another UPF to recover the failed PDU session, if a partial failure recovery message sent by the UPF is received and the target PDU session recovery policy is a priority reselection UPF, the target PDU session recovery policy applying module further comprises:

34. The apparatus of claim 31 or 33, further comprising: