Network node, method, and program

Abstract

The present disclosure provides a network node, method, and program that can accurately grasp the PFCP association status. [Solution] A first network node according to the present disclosure is a first network node of a first network node and a second network node, one of which is a Control Plane Function and the other is a User Plane Function, and sends a first message to the second network node in a PFCP association update procedure to confirm the status of a Packet Forwarding Control Protocol (PFCP) association in the second network node, and receives a first response message to the first message from the second network node in the PFCP association update procedure, the first response message including information regarding the status of the PFCP association in the second network node.

Description

[Technical Field]

[0001] The present disclosure relates to a network node, a method, and a program. [Background technology]

[0002] 3GPP (registered trademark) (3rd Generation Partnership Project) has established specifications for a 5th generation mobile communication system (5G, New Radio (NR)) (for example, Non-Patent Document 1).

[0003] In the 5G Core network (5GC), the User Plane Function (UPF), which controls the U (User)-Plane, and the Session Management Function (SMF), which manages sessions and controls paths for the UPF, are connected by the Packet Forwarding Control Protocol (PFCP).

[0004] As specified in Non-Patent Document 1, PFCP entities connected by PFCP use the Heartbeat Procedure to detect failures and restarts of the connected node. For example, Non-Patent Document 1 specifies that each PFCP entity sends a Heartbeat Request message to the PFCP entity of the peer node with which a PFCP association is established. Then, the User Plane Function (or Control Plane (C-Plane) Function) that receives the Heartbeat Request message replies with a Heartbeat Response message. [Prior art documents] [Non-patent literature]

[0005] [Non-Patent Document 1] 3GPP TS 29.244 V18.5.0 Technical Specification “3rd Generation Partnership Project; Technical Specification Group Core Network and Terminals; Interface between the Control Plane and the User Plane Nodes; Stage 3 (Release 18)”, March 2024 Summary of the Invention [Problem to be solved by the invention]

[0006] Incidentally, Non-Patent Document 1 specifies that a User Plane Function (or C-Plane Function) that receives a Heartbeat Request message will return a Heartbeat Response message even if the peer node that sent the Heartbeat Request message is unknown. According to this specification, a User Plane Function (or C-Plane Function) that receives a Heartbeat Request message will send a Heartbeat Response even if the "PFCP association state" with the node that sent the Heartbeat Request message is "unestablished." On the other hand, because the node that sent the Heartbeat Request message receives the Heartbeat Response, it understands that the "PFCP control association state" of the node that sent the Heartbeat Response is "connected."

[0007] For this reason, it may not be possible to accurately grasp the "PFCP association state" managed in each of two network nodes that can be connected by PFCP.

[0008] An object of the present disclosure is to provide a network node, a method, and a program that can accurately grasp the PFCP association state. It should be noted that this object is only one of multiple objects that multiple embodiments disclosed in this specification aim to achieve. Other objects or problems and novel features will become apparent from the description of this specification or the accompanying drawings. [Means for solving the problem]

[0009] A first network node according to the present disclosure is a first network node of a first network node and a second network node, one of which is a Control Plane Function and the other is a User Plane Function, and comprises at least one memory and at least one processor coupled to the at least one memory, wherein the at least one processor transmits a first message to the second network node in a Packet Forwarding Control Protocol (PFCP) association update procedure to confirm a status of a PFCP association in the second network node, and receives a first response message to the first message from the second network node in the PFCP association update procedure, the first response message including information regarding the status of the PFCP association in the second network node.

[0010] The second network node of the present disclosure is a second network node of a first network node and a second network node, one of which is a Control Plane Function and the other is a User Plane Function, and comprises at least one memory and at least one processor coupled to the at least one memory, wherein the at least one processor receives a first message for confirming a status of a Packet Forwarding Control Protocol (PFCP) association at the second network node from the first network node in a PFCP association update procedure, and in response to receiving the first message, transmits a first response message to the first message to the first network node in the PFCP association update procedure, the first response message including information regarding the status of the PFCP association at the second network node.

[0011] The method disclosed herein is a method executed by a first network node of a first network node and a second network node, one of which is a Control Plane Function and the other is a User Plane Function, and includes: sending a first message to the second network node in a PFCP association update procedure to confirm a status of a Packet Forwarding Control Protocol (PFCP) association in the second network node; and receiving a first response message to the first message from the second network node in the PFCP association update procedure, the first response message including information regarding the status of the PFCP association in the second network node.

[0012] A program according to the present disclosure is a program that causes a first network node of a first network node and a second network node, one of which is a Control Plane Function and the other is a User Plane Function, to execute processing, the processing including: sending a first message to the second network node in a PFCP association update procedure to confirm a status of a PFCP (Packet Forwarding Control Protocol) association in the second network node; and receiving a first response message to the first message from the second network node in the PFCP association update procedure, the first response message including information regarding the status of the PFCP association in the second network node. [Effects of the Invention]

[0013] The present disclosure provides a network node, method, and program that can accurately grasp the PFCP association status. [Brief explanation of the drawings]

[0014] [Figure 1] FIG. 1 is a block diagram illustrating an example of a system of the present disclosure. [Figure 2] FIG. 10 is a diagram illustrating an example of a processing operation of the system of the present disclosure. [Figure 3] FIG. 10 is a diagram illustrating another example of the processing operation of the system of the present disclosure. [Figure 4] FIG. 10 is a diagram illustrating a case in which a mismatch in the PFCP association state occurs. [Figure 5] FIG. 1 illustrates an example of the configuration of a network node. DETAILED DESCRIPTION OF THE INVENTION

[0015] Hereinafter, embodiments will be described with reference to the drawings. In this disclosure, the drawings may relate to one or more embodiments. Furthermore, each element in the drawings may apply to one or more embodiments. Furthermore, in the embodiments, identical or equivalent elements are given the same reference numerals, and redundant explanations will be omitted.

[0016] First Embodiment <System configuration example> Fig. 1 is a block diagram showing an example of a system of the present disclosure. In Fig. 1, the system includes a network node (first network node) 10 and a network node (second network node) 20. One of network node 10 and network node 20 is a Control Plane Function, and the other is a User Plane Function. Network node 10 and network node 20 may be connected by a PFCP. For example, the Control Plane Function is an SMF of 5GC, and the User Plane Function is a UPF of 5GC.

[0017] 1, a network node 10 includes a control unit 11. Also, a network node 20 includes a control unit 21.

[0018] The control unit 11 controls transmission of a first message to the network node 20 for confirming the state of the PFCP association between the network node 10 and the network node 20, which is managed in the network node 20. For example, the control unit 11 may control transmission of the first message when the state of the PFCP association between the network node 10 and the network node 20, which is managed in the network node 10, is "connected". The transmission of the first message may be performed at any timing. On the other hand, the control unit 11 does not need to control transmission of the first message when the state of the PFCP association between the network node 10 and the network node 20, which is managed in the network node 10, is "disconnected". The transmission of this first message is performed, for example, in a PFCP association update procedure. The first message is, for example, a PFCP association update request.

[0019] The control unit 11 receives a first response message in response to the first message transmitted from the network node 20. The first response message includes information on the state of the PFCP association between the network node 10 and the network node 20, which is managed in the network node 20. This first response message is transmitted from the network node 20 to the network node 10 in, for example, a PFCP Association Update Procedure. The first response message is, for example, a PFCP Association Update Response.

[0020] The control unit 21 receives the first message transmitted from the network node 10 .

[0021] In response to receiving the first message, the control unit 21 performs control to transmit the above-mentioned first response message to the network node 10.

[0022] <System operation example> FIG. 2 is a diagram illustrating an example of the processing operation of the system of the present disclosure.

[0023] The network node 10 transmits a first message to the network node 20 for checking the state of the PFCP association between the network node 10 and the network node 20, which is managed in the network node 20 (step S11).

[0024] In response to receiving the first message, the network node 20 transmits a first response message to the network node 10 (step S12).

[0025] As described above, according to the first embodiment, the control unit 11 in the network node 10 transmits to the network node 20 a first message for confirming the state of the PFCP association between the network node 10 and the network node 20, which is managed in the network node 20. Then, the control unit 11 receives a first response message in response to the first message, which is transmitted from the network node 20. The first response message includes information regarding the state of the PFCP association between the network node 10 and the network node 20, which is managed in the network node 20.

[0026] This configuration of the network node 10 makes it possible to accurately grasp the "PFCP association state" managed in each of two network nodes that can be connected by the PFCP.

[0027] Note that, in the above description, a case has been described in which the network node 10 transmits a message and the network node 20 transmits a response message, but the present disclosure is not limited to this. The network node 20 may transmit a message to the network node 10 to confirm the state of the PFCP association between the network node 10 and the network node 20, which is managed in the network node 10. Furthermore, the network node 10 may transmit to the network node 20 a response message in response to the message transmitted from the network node 20. This response message includes information regarding the state of the PFCP association between the network node 10 and the network node 20, which is managed in the network node 10.

[0028] Second Embodiment The system configuration of the second embodiment is the same as the system configuration of the first embodiment, so refer to Fig. 1. In the second embodiment, as an example, the network node 10 is an SMF, and the network node 20 is a UPF.

[0029] 3 is a diagram showing another example of the processing operation of the system of the present disclosure. First, the state of the PFCP association between the SMF 10 and the UPF 20, which is managed by the SMF 10, is "connected." On the other hand, the state of the PFCP association between the SMF 10 and the UPF 20, which is managed by the UPF 20, is "disconnected." Cases in which such a mismatch occurs will be described later with reference to FIG. 4.

[0030] The control unit 11 of the SMF 10 transmits a PFCP association update request to the UPF 20 (step S21). This PFCP association update request is a message for confirming the status of the PFCP association between the SMF 10 and the UPF 20, which is managed by the UPF 20. This PFCP association update request may include identification information (Node ID) of the SMF 10 and information on the functional features of the SMF 10 (CP Function Features).

[0031] In response to receiving the PFCP association update request, control unit 21 of UPF 20 transmits a PFCP association update response to SMF 10 (step S22). The PFCP association update response includes a "Cause value" indicating the state of the PFCP association managed by control unit 21 of UPF 20. In this case, the state of the PFCP association managed by UPF 20 is "disconnected," so the PFCP association update response includes a "Cause value" indicating "disconnected." The PFCP association update response may further include identification information (Node ID) of UPF 20 and information on the functional features of UPF 20 (UP Function Features).

[0032] If the "Cause value" included in the PFCP association update response indicates "disconnected," the control unit 11 of the SMF 10 changes the state of the PFCP association managed by the control unit 11 from "connected" to "disconnected" (step S23).

[0033] The controller 11 of the SMF 10 transmits a second message to the UPF 20 for setting up a PFCP association between the SMF 10 and the UPF 20 (step S24). The second message is, for example, a PFCP Association Setup Request.

[0034] In response to receiving the second message, the control unit 21 of the UPF 20 transmits a second response message to the SMF 10 (step S25). The second response message is, for example, a PFCP Association Setup Response. The second response message includes, for example, information indicating that the PFCP association setup has been successful.

[0035] The control unit 21 of the UPF 20 changes the state of the PFCP association managed by the control unit 21 from "disconnected" to "connected" (step S26).

[0036] The control unit 11 of the SMF 10 changes the state of the PFCP association managed by the control unit 11 from "disconnected" to "connected" (step S27).

[0037] Next, an example of a case where a mismatch in the PFCP association state occurs will be described. Figure 4 is a diagram illustrating a case where a mismatch in the PFCP association state occurs.

[0038] The control unit 11 of the SMF 10 transmits a PFCP association setup request to the UPF 20 (step S31).

[0039] In response to receiving the PFCP association setup request, the control unit 21 of the UPF 20 transmits a PFCP association setup response to the SMF 10 (step S32). This PFCP association setup response includes information indicating that the PFCP association setup has been successful. In this case, the state of the PFCP association managed by the control unit 21 of the UPF 20 becomes "connected." The state of the PFCP association managed by the control unit 11 of the SMF 10 also becomes "connected."

[0040] The control unit 11 of the SMF 10 transmits a PFCP heartbeat request to the UPF 20 (step S33).

[0041] In response to receiving the PFCP heartbeat request, the control unit 21 of the UPF 20 transmits a PFCP heartbeat response to the SMF 10 (step S34). By receiving the PFCP heartbeat response, the control unit 21 of the UPF 20 determines that the state of the PFCP association managed by the control unit 21 of the UPF 20 is "connected."

[0042] The control unit 21 of the UPF 20 transmits a PFCP heartbeat request to the SMF 10 (step S35). However, in this case, it is assumed that the control unit 21 of the UPF 20 transmits a PFCP heartbeat request to the SMF 10 a specified number of times, but none of the requests reaches the SMF 10.

[0043] The control unit 21 of the UPF 20 changes the state of the PFCP association managed by the control unit 21 from "connected" to "disconnected" (step S36).

[0044] The control unit 11 of the SMF 10 transmits a PFCP heartbeat request to the UPF 20 (step S37).

[0045] In response to receiving the PFCP heartbeat request, the control unit 21 of the UPF 20 transmits a PFCP heartbeat response to the SMF 10 (step S38). By receiving the PFCP heartbeat response, the control unit 21 of the UPF 20 determines that the state of the PFCP association managed by the control unit 21 of the UPF 20 is "connected."

[0046] In this way, a mismatch in the PFCP association state may occur. However, by executing the PFCP association update procedure described above with reference to Figure 3, the PFCP association state managed by the control unit 11 of the SMF 10 and the PFCP association state managed by the control unit 21 of the UPF 20 can be made to match. Note that if the PFCP session establishment procedure is executed between the SMF 10 and the UPF 20 when the PFCP association states are in a mismatched state, a "call loss" will occur. However, as described above, the PFCP association state managed by the control unit 11 of the SMF 10 and the PFCP association state managed by the control unit 21 of the UPF 20 can be made to match, so that the "call loss" can be avoided.

[0047] <Other embodiments> Fig. 5 is a diagram showing an example of the configuration of a network node. In Fig. 5, an apparatus 100 includes a network interface 101, a processor 102, and a memory 103. The network nodes 10 and 20 may have the configuration shown in Fig. 5.

[0048] The network interface 101 is used to communicate with, for example, network elements (e.g., other network nodes) and may include, for example, a network interface card (NIC) that complies with the IEEE 802.3 series.

[0049] The processor 102 may be, for example, a microprocessor, an MPU, or a CPU. The processor 102 may include multiple processors.

[0050] The memory 103 is composed of volatile memory and nonvolatile memory. The memory 103 may include multiple physically independent memory devices. The volatile memory is, for example, Static Random Access Memory (SRAM), Dynamic RAM (DRAM), or a combination thereof. The nonvolatile memory is, for example, Mask Read Only Memory (MROM), Electrically Erasable Programmable ROM (EEPROM), flash memory, or a hard disk drive, or any combination thereof. The memory 103 may include storage located remotely from the processor 102. In this case, the processor 102 may access the memory 103 via the network interface 101 or an I / O interface.

[0051] The memory 103 may store one or more software modules (computer programs) including instructions and data for performing the operations of the network nodes 10, 20 described in the above-described embodiments. In some implementations, the processor 102 may be configured to read and execute the software modules from the memory 103 to perform the operations of the network nodes 10, 20 described in the above-described embodiments.

[0052] Although the present invention has been described above with reference to the embodiments, the present invention is not limited to the above. Various modifications that can be understood by those skilled in the art can be made to the configuration and details of the present invention within the scope of the invention. Furthermore, each embodiment can be combined with other embodiments as appropriate.

[0053] Each drawing is merely an example for describing one or more embodiments. Each drawing may relate not only to one particular embodiment, but also to one or more other embodiments. As will be understood by those skilled in the art, various features or steps described with reference to any one drawing can be combined with features or steps shown in one or more other drawings to create, for example, an embodiment not explicitly shown or described. Not all features or steps shown in any one drawing are necessary to describe an exemplary embodiment, and some features or steps may be omitted. The order of steps described in any drawing may be changed as appropriate.

[0054] A part or all of the above-described embodiments can be described as, but not limited to, the following supplementary notes. (Appendix 1) The first network node of a first network node and a second network node, one of which is a Control Plane Function and the other of which is a User Plane Function, At least one memory; at least one processor coupled to the at least one memory; Equipped with The at least one processor: sending a first message to the second network node in a Packet Forwarding Control Protocol (PFCP) association update procedure to confirm a state of a PFCP association at the second network node; receiving a first response message to the first message from the second network node in the PFCP association update procedure, the first response message including information regarding a state of a PFCP association at the second network node; First network node. (Appendix 2) The information about the state of the PFCP association is a Cause value; 10. The first network node of claim 1. (Appendix 3) the at least one processor, when the information on the state of the PFCP association indicates a disconnected state, sets the state of the PFCP association in the first network node to a disconnected state and sends a second message to the second network node to set up the PFCP association; 3. The first network node according to claim 1 or 2. (Appendix 4) The at least one processor: receiving a second response message to the second message, the second response message including information indicating that the PFCP association has been successfully set up; In response to receiving the second response message, changing the state of the PFCP association in the first network node from the disconnected state to a connected state; 4. The first network node of claim 3. (Appendix 5) The at least one processor: If the state of the PFCP association in the first network node is the connected state, sending a heartbeat request to the second network node; changing the state of the PFCP association in the first network node from the connected state to the disconnected state when no heartbeat response to the heartbeat request is received from the second network node; 5. The first network node of claim 4. (Appendix 6) the first message includes an identification of the first network node and information about functional characteristics of the first network node; 3. The first network node according to claim 1 or 2. (Appendix 7) the first response message further includes identification information of the second network node and information about functional characteristics of the second network node; 3. The first network node according to claim 1 or 2. (Appendix 8) the first message is a PFCP association update request; 3. The first network node according to claim 1 or 2. (Appendix 9) The first response message is a PFCP association update response. 3. The first network node according to claim 1 or 2. (Appendix 10) The second network node of the first network node and the second network node, one of which is a Control Plane Function and the other of which is a User Plane Function, At least one memory; at least one processor coupled to the at least one memory; Equipped with The at least one processor: receiving a first message from the first network node in a Packet Forwarding Control Protocol (PFCP) association update procedure to confirm a state of a PFCP association at the second network node; In response to receiving the first message, sending a first response message to the first message to the first network node in the PFCP association update procedure, the first response message including information about a state of the PFCP association at the second network node; Second network node. (Appendix 11) The information about the state of the PFCP association is a Cause value; 11. The second network node of claim 10. (Appendix 12) when the state of the PFCP association in the second network node is a disconnected state, the at least one processor transmits the first response message to the first network node, the first response message including information indicating the disconnected state as information regarding the state of the PFCP association in the second network node; 12. The second network node according to claim 10 or 11. (Appendix 13) The at least one processor: receiving a second message from the first network node for setting up the PFCP association; If the setup of the PFCP association is successful, change the state of the PFCP association in the second network node from the disconnected state to a connected state, and send a second response message to the second message to the first network node, the second response message including information indicating that the setup of the PFCP association is successful; 13. The second network node of claim 12. (Appendix 14) The at least one processor: If the state of the PFCP association in the second network node is the connected state, sending a heartbeat request to the first network node; if no heartbeat response to the heartbeat request is received from the first network node, changing the state of the PFCP association at the second network node from the connected state to the disconnected state; 14. The second network node of claim 13. (Appendix 15) the first message includes an identification of the first network node and information about functional characteristics of the first network node; 12. The second network node according to claim 10 or 11. (Appendix 16) the first response message further includes identification information of the second network node and information about functional characteristics of the second network node; 12. The second network node according to claim 10 or 11. (Appendix 17) the first message is a PFCP association update request; 12. The second network node according to claim 10 or 11. (Appendix 18) The first response message is a PFCP association update response. 12. The second network node according to claim 10 or 11. (Appendix 19) A method executed by a first network node among a first network node and a second network node, one of which is a Control Plane Function and the other of which is a User Plane Function, the first network node comprising: sending a first message to the second network node in a Packet Forwarding Control Protocol (PFCP) association update procedure to confirm a state of a PFCP association at the second network node; receiving a first response message to the first message from the second network node in the PFCP association update procedure, the first response message including information regarding a state of a PFCP association at the second network node; A method comprising: (Appendix 20) The information about the state of the PFCP association is a Cause value; The method described in Appendix 19. (Appendix 21) If the information on the state of the PFCP association indicates a disconnected state, setting the state of the PFCP association in the first network node to a disconnected state and sending a second message to the second network node to set up the PFCP association. 21. The method of claim 19 or 20. (Appendix 22) receiving a second response message to the second message, the second response message including information indicating that the PFCP association has been successfully set up; In response to receiving the second response message, changing the state of the PFCP association in the first network node from the disconnected state to a connected state; 22. The method of claim 21, comprising: (Appendix 23) If the state of the PFCP association in the first network node is the connected state, sending a heartbeat request to the second network node; changing the state of the PFCP association at the first network node from the connected state to the disconnected state when no heartbeat response to the heartbeat request is received from the second network node; 23. The method of claim 22, comprising: (Appendix 24) the first message includes an identification of the first network node and information about functional characteristics of the first network node; 21. The method of claim 19 or 20. (Appendix 25) the first response message further includes identification information of the second network node and information about functional characteristics of the second network node; 21. The method of claim 19 or 20. (Appendix 26) the first message is a PFCP association update request; 21. The method of claim 19 or 20. (Appendix 27) The first response message is a PFCP association update response. 21. The method of claim 19 or 20. (Appendix 28) A method executed by a second network node of a first network node and a second network node, one of which is a Control Plane Function and the other is a User Plane Function, the method comprising: receiving a first message from the first network node in a Packet Forwarding Control Protocol (PFCP) association update procedure to confirm a state of a PFCP association at the second network node; In response to receiving the first message, sending a first response message to the first message to the first network node in the PFCP association update procedure, the first response message including information regarding a state of a PFCP association at the second network node; A method comprising: (Appendix 29) The information about the state of the PFCP association is a Cause value; The method described in Appendix 28. (Appendix 30) If the state of the PFCP association in the second network node is a disconnected state, transmitting the first response message to the first network node, the first response message including information indicating the disconnected state as information regarding the state of the PFCP association in the second network node. 29. The method of claim 28 or 29. (Appendix 31) receiving a second message from the first network node for setting up the PFCP association; If the setup of the PFCP association is successful, changing the state of the PFCP association in the second network node from the disconnected state to a connected state, and sending a second response message to the second message to the first network node, the second response message including information indicating that the setup of the PFCP association is successful; 31. The method of claim 30, comprising: (Appendix 32) If the state of the PFCP association in the second network node is the connected state, sending a heartbeat request to the first network node; changing the state of the PFCP association at the second network node from the connected state to the disconnected state when no heartbeat response to the heartbeat request is received from the first network node; 32. The method of claim 31, comprising: (Appendix 33) the first message includes an identification of the first network node and information about functional characteristics of the first network node; 29. The method of claim 28 or 29. (Appendix 34) the first response message further includes identification information of the second network node and information about functional characteristics of the second network node; 29. The method of claim 28 or 29. (Appendix 35) the first message is a PFCP association update request; 29. The method of claim 28 or 29. (Appendix 36) The first response message is a PFCP association update response. 29. The method of claim 28 or 29. (Appendix 37) A program for causing a first network node of a first network node and a second network node, one of which is a Control Plane Function and the other of which is a User Plane Function, to execute processing, The process comprises: sending a first message to the second network node in a Packet Forwarding Control Protocol (PFCP) association update procedure to confirm a state of a PFCP association at the second network node; receiving a first response message to the first message from the second network node in the PFCP association update procedure, the first response message including information regarding a state of a PFCP association at the second network node; Including, the program. (Appendix 38) The information about the state of the PFCP association is a Cause value; The program described in Appendix 37. (Appendix 39) the processing includes, when the information on the state of the PFCP association indicates a disconnected state, setting the state of the PFCP association in the first network node to a disconnected state and sending a second message to the second network node to set up the PFCP association; 39. The program according to claim 37 or 38. (Appendix 40) The process comprises: receiving a second response message to the second message, the second response message including information indicating that the PFCP association has been successfully set up; In response to receiving the second response message, changing the state of the PFCP association in the first network node from the disconnected state to a connected state; 39. The program of claim 39, (Appendix 41) The process comprises: If the state of the PFCP association in the first network node is the connected state, sending a heartbeat request to the second network node; changing the state of the PFCP association at the first network node from the connected state to the disconnected state when no heartbeat response to the heartbeat request is received from the second network node; 41. The program of claim 40, comprising: (Appendix 42) the first message includes an identification of the first network node and information about functional characteristics of the first network node; 39. The program according to claim 37 or 38. (Appendix 43) the first response message further includes identification information of the second network node and information about functional characteristics of the second network node; 39. The program according to claim 37 or 38. (Appendix 44) the first message is a PFCP association update request; 39. The program according to claim 37 or 38. (Appendix 45) The first response message is a PFCP association update response. 39. The program according to claim 37 or 38. (Appendix 46) A program for causing a second network node of a first network node and a second network node, one of which is a Control Plane Function and the other of which is a User Plane Function, to execute processing, The process comprises: receiving a first message from the first network node in a Packet Forwarding Control Protocol (PFCP) association update procedure to confirm a state of a PFCP association at the second network node; In response to receiving the first message, sending a first response message to the first message to the first network node in the PFCP association update procedure, the first response message including information regarding a state of a PFCP association at the second network node; Including, the program. (Appendix 47) The information about the state of the PFCP association is a Cause value; The program described in Appendix 46. (Appendix 48) the processing includes, when the state of the PFCP association in the second network node is a disconnected state, transmitting the first response message to the first network node, the first response message including information indicating the disconnected state as information regarding the state of the PFCP association in the second network node; 48. The program according to claim 46 or 47. (Appendix 49) The process comprises: receiving a second message from the first network node for setting up the PFCP association; If the setup of the PFCP association is successful, changing the state of the PFCP association in the second network node from the disconnected state to a connected state, and sending a second response message to the second message to the first network node, the second response message including information indicating that the setup of the PFCP association is successful; 49. The program of claim 48, comprising: (Appendix 50) The process comprises: If the state of the PFCP association in the second network node is the connected state, sending a heartbeat request to the first network node; changing the state of the PFCP association at the second network node from the connected state to the disconnected state when no heartbeat response to the heartbeat request is received from the first network node; 49. The program of claim 49, (Appendix 51) the first message includes an identification of the first network node and information about functional characteristics of the first network node; 48. The program according to claim 46 or 47. (Appendix 52) the first response message further includes identification information of the second network node and information about functional characteristics of the second network node; 48. The program according to claim 46 or 47. (Appendix 53) the first message is a PFCP association update request; 48. The program according to claim 46 or 47. (Appendix 54) The first response message is a PFCP association update response. 48. The program according to claim 46 or 47. [Explanation of symbols]

[0055] 10 Network Node (First Network Node) 11 Control section 20 network nodes (second network nodes) 21 Control section

Claims

1. The first network node of a first network node and a second network node, one of which is a Control Plane Function and the other of which is a User Plane Function, at least one memory; at least one processor coupled to the at least one memory; Equipped with The at least one processor sending a first message to the second network node in a Packet Forwarding Control Protocol (PFCP) association update procedure to confirm a state of a PFCP association at the second network node; receiving a first response message to the first message from the second network node in the PFCP association update procedure, the first response message including information regarding a state of a PFCP association at the second network node; First network node.

2. The information about the state of the PFCP association is a Cause value; The first network node of claim 1 .

3. the at least one processor, when the information on the state of the PFCP association indicates a disconnected state, sets the state of the PFCP association in the first network node to a disconnected state and sends a second message to the second network node to set up the PFCP association; 3. A first network node according to claim 1 or 2.

4. the first message includes an identification of the first network node and information about functional characteristics of the first network node.

3. A first network node according to claim 1 or 2.

5. the first response message further includes an identification of the second network node and information about functional characteristics of the second network node.

3. A first network node according to claim 1 or 2.

6. The second network node of the first network node and the second network node, one of which is a Control Plane Function and the other of which is a User Plane Function, at least one memory; at least one processor coupled to the at least one memory; Equipped with The at least one processor receiving a first message from the first network node in a Packet Forwarding Control Protocol (PFCP) association update procedure to confirm a state of a PFCP association at the second network node; In response to receiving the first message, sending a first response message to the first message to the first network node in the PFCP association update procedure, the first response message including information regarding a state of the PFCP association at the second network node; A second network node.

7. A method executed by a first network node among a first network node and a second network node, one of which is a Control Plane Function and the other of which is a User Plane Function, the method comprising: sending a first message to the second network node in a Packet Forwarding Control Protocol (PFCP) association update procedure to confirm a state of a PFCP association at the second network node; receiving a first response message to the first message from the second network node in the PFCP association update procedure, the first response message including information regarding a state of a PFCP association at the second network node; A method comprising:

8. A method executed by a second network node of a first network node and a second network node, one of which is a Control Plane Function and the other is a User Plane Function, the method comprising: receiving a first message from the first network node in a Packet Forwarding Control Protocol (PFCP) association update procedure to confirm a state of a PFCP association at the second network node; In response to receiving the first message, sending a first response message to the first message to the first network node in the PFCP association update procedure, the first response message including information regarding a state of a PFCP association at the second network node; A method comprising:

9. A program for causing a first network node of a first network node and a second network node, one of which is a Control Plane Function and the other of which is a User Plane Function, to execute processing, the program comprising: The process comprises: sending a first message to the second network node in a Packet Forwarding Control Protocol (PFCP) association update procedure to confirm a state of a PFCP association at the second network node; receiving a first response message to the first message from the second network node in the PFCP association update procedure, the first response message including information regarding a state of a PFCP association at the second network node; Including, the program.

10. A program for causing a second network node of a first network node and a second network node, one of which is a Control Plane Function and the other of which is a User Plane Function, to execute processing, The process comprises: receiving a first message from the first network node in a Packet Forwarding Control Protocol (PFCP) association update procedure to confirm a state of a PFCP association at the second network node; In response to receiving the first message, sending a first response message to the first message to the first network node in the PFCP association update procedure, the first response message including information regarding a state of a PFCP association at the second network node; Including, the program.

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