Control device, communication system, and control method

Abstract

A control device comprising: an NF management unit for managing an NF in a distributed mobile core network; a condition management unit for detecting that a predetermined condition related to the NF is not satisfied at present or in the future; and a scheduling unit for scheduling the arrangement change of the NF so that the predetermined condition is satisfied when it is detected by the condition management unit that the predetermined condition is not satisfied.

Description

Control device, communication system and control method

[0001] This application claims priority to Japanese Patent Application No. 2023-147276, filed on September 12, 2023, the contents of which are incorporated herein by reference.

[0002] <Examples of Distributed Mobile Network Configurations> FIG. 10 is a diagram showing examples of distributed mobile network configurations. These configurations are described in Non-Patent Document 1. In the Local Offload option, a User Plane Function (UPF) for data communication is located at an edge site, and a Control-Plane (C-Plane) NF for processing control information is located at a central site. The UPF can either offload data traffic to a local Application Function (AF) or forward the data traffic to the central site. In either case, C-Plane signals are exchanged via a backhaul. This option is suitable for environments where edge nodes are unreliable or for use cases where end-to-end services are not affected by latency or capacity (e.g., aerial communications or live content acquisition using nomadic networks).

[0003] In the Locally Administered Edge option, an Access and Mobility Management Function (AMF) and a Session Management Function (SMF) are deployed at the edge site to perform authentication, authorization, and session management at the edge. As a result, certain C-Plane signaling (e.g., Service Request Procedure) between the edge and the central is completed at the edge site, reducing it. This option is suitable when applying specific local policies to the edge or when there is a backhaul with significant latency characteristics.

[0004] The Autonomous Edge option places all C-Plane NF functions on the edge network, providing connectivity to devices within a specific region. However, this model is limited to certain areas and does not provide continuous device mobility. To provide connectivity across edge networks, subscriber profile synchronization is required. This option is best suited for deployments requiring ultra-low latency or where backhaul availability and capacity are very limited and there is a high degree of trust in the edge infrastructure.

[0005] FIG. 10 also shows an AUSF (Authentication User Service Function), a UDM (Unified Data Management), a PCF (Policy Control Function), a 5G terminal UE (User Equipment), and a 5G base station gNB.

[0006] <CORBA> Non-Patent Document 2 describes CORBA (Common Object Request Broker Architecture). CORBA is an open architecture defined in 1989 that aims to standardize distributed object systems. CORBA is a collection of specifications and protocols that enable remote calls between clients and servers and achieve interoperability between different programming languages ​​or different platforms.

[0007] ORB (Object Request Broker) is the core function of CORBA and plays a role of mediating communication between clients and servers. ORB handles communication between objects, such as object creation and deletion, method invocation, and data transfer. ORB interacts with applications that comply with the CORBA specifications and manages the exchange of requests and responses. The combination of client / server and ORB enables objects developed in different programming languages ​​or on different platforms to communicate transparently. CORBA increases the freedom of choice of programming language and platform, and provides a means for improving system scalability and flexibility. Furthermore, as described in non-patent document 3, ORB supports communication using shared memory.

[0008] The C-Plane of the current 5G CORE network adopts SBA (Service Based Architecture). In SBA, service-based modules called NFs (Network Functions) have SBIs (Service Based Interfaces) and use HTTP (Hyper Text Transfer Protocol) to exchange information. In 5G or 6G, since connections from many UEs or UE mobility are expected, a large amount of signaling between NFs to complete procedures such as registration and handover (HO) may occur, which may lead to congestion in the C-Plane called a signaling storm (Non-Patent Document 4).

[0009] Therefore, in order to reduce the processing load due to HTTP signaling, a technique called componentization has been proposed (Non-Patent Document 5). Componentized NFs are deployed on the same server, and a communication method via hardware / software resources such as shared memory (e.g., POSIX shared memory communication method) is used as the communication method between NFs. By replacing HTTP with a different communication method in this way, it is expected that not only the communication cost due to HTTP signaling (e.g., the load on the communication path between NFs) will be reduced, but also the overhead of the processing required for HTTP signaling will be reduced. The processing in question is, for example, parsing (analyzing packets) and deparsing (reassembling packets).

[0010] FIG. 11 is a diagram showing an example of componentization using NFs to which CORBA is applied. FIG. 11 shows an example of an SBA configuration and an example of a componentized configuration. It is expected that components can be implemented by applying CORBA to NFs. In the example of FIG. 11, three NFs are shown as NF#1 to NF#3. In CORBA, an ORB is placed in each NF. Assume that communication is performed from NF#3 to NF#1 via NF#2. In this case, with SBA, a total of four HTTP signalings and eight HTTP parse / deparse operations occur. On the other hand, in a configuration in which NF#1 and NF#2 are componentized, POSIX shared memory communication is applied to communication between NF#1 and NF#2. Therefore, a total of two HTTP signalings and four HTTP parse / deparse operations occur, halving the load due to HTTP signaling.

[0011] Marius Corici, et al. “A Study of 5G Edge-Central Core Network Split Options,” Network 1.3 (2021): 354-368. https: / / www.mdpi.com / 2673-8732 / 1 / 3 / 20 “Let’s First Review the Basics of CORBA,” https: / / atmarkit.itmedia.co.jp / ait / articles / 0103 / 08 / news002.html “CORBA with Shared Memory,” https: / / cmsdoc.cern.ch / ~gutleber / drthesis / node54.html Ahmad, Ijaz, et al. “5G security: Analysis of threats and solutions.” 2017 IEEE Conference on Standards for Communications and Networking (CSCN). IEEE, 2017. Masayuki Kurata and two others, “A Study on Distributed Mobile Core Networks Focusing on NWDAF,” Research Report on Multimedia Communications and Distributed Processing (DPS), 2023-DPS-195.

[0012] However, the number and amount of procedures (e.g., Registration, HO, Service Request) to be processed by the 5G C-Plane, including the CU (Central Unit)-CP, which is an NF of the RAN (Radio Access Networks), varies depending on time or location. For this reason, the number or amount of signaling between each NF is expected to change in real time. In this case, when each option is statically (fixedly) adopted in a distributed mobile network, the following (Problem 1) to (Problem 3) can be considered.

[0013] (Problem 1) It is expected that group HOs will occur frequently during busy morning or evening travel times. In this case, if the Locally Administered Edge option or the Autonomous Edge option is adopted, HOs will occur frequently each time a device moves to a different edge site. This will lead to an increase in the processing load on the NF. (Problem 2) If access to the edge application server is concentrated and the number of service requests increases, adopting the Local Offload option will increase signaling at both the edge site and the central site. (Problem 3) If the Autonomous Edge option is not adopted, it will be impossible to meet the SLA (Service Level Agreement) of delay-critical applications.

[0014] These problems can be addressed by dynamically arranging NFs in appropriate positions. However, in the current distributed mobile core network, there is a problem that NFs cannot be dynamically changed because there is no decision function or device for making the decision, and no device, interface, or procedure for executing instructions for dynamically changing the placement of NFs.

[0015] The present disclosure has been made in consideration of the above circumstances, and an example of an objective thereof is to provide a control device, a communication system, and a control method that can support dynamic relocation of NFs.

[0016] As one configuration example, the control device includes an NF management unit that manages NFs (Network Functions) in a distributed mobile core network, a condition management unit that detects that a specified condition related to the NF is not satisfied at present or in the future, and a scheduling unit that, when the condition management unit detects that the specified condition is not satisfied, schedules a change in the placement of the NF so that the specified condition is satisfied.

[0017] As one configuration example, there is provided a communication system having an NF (Network Function) in a distributed mobile core network and a control device, wherein the control device comprises an NF management unit that manages the NF, a condition management unit that detects that a specified condition related to the NF is not satisfied at present or in the future, and a scheduling unit that schedules a change in the placement of the NF so that the specified condition is satisfied when the condition management unit detects that the specified condition is not satisfied, and the NF performs a process of changing its placement in accordance with the scheduling.

[0018] As one configuration example, this is a control method in which an NF (Network Function) management unit manages NFs in a distributed mobile core network, a condition management unit detects that a specified condition related to the NF is not satisfied at present or in the future, and a scheduling unit schedules a change in the placement of the NF so that the specified condition is satisfied when the condition management unit detects that the specified condition is not satisfied.

[0019] According to the control device, communication system, and control method according to the present disclosure, as one example, dynamic relocation of NFs can be supported.

[0020] 1 is a diagram showing a schematic configuration example of a control device compatible with CORBA according to an embodiment. FIG. 1 is a diagram showing typically an example of an NF management function according to an embodiment. FIG. 2 is a diagram showing typically an example of a metrics / alert management function according to an embodiment. FIG. 3 is a diagram showing typically an example of a scheduling function according to an embodiment. FIG. 4 is a diagram showing typically an example of a component list management function according to an embodiment. FIG. 5 is a diagram showing typically an example of a procedure for processing performed in a communication system according to an embodiment. FIG. 6 is a diagram showing typically an example of processing performed in a communication system according to an embodiment. FIG. 7 is a diagram showing typically an example of a procedure for processing performed in a communication system according to an embodiment.

[0021] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings.

[0022] A first embodiment will be described. (Configuration Example When CORBA is Applied) [Control Device] Fig. 1 is a diagram showing a schematic configuration example of a control device 11 that supports CORBA according to an embodiment. The control device 11 includes a processing unit 111 and a communication unit 112. The processing unit 111 includes an NF management unit 131 having an NF management function, a metrics / alert management unit 132 having a metrics / alert management function, a scheduling unit 133 having a scheduling function, and a component list management unit 134 having a component management function. The communication unit 112 includes an interface 151. Each unit of the control device 11 may be realized by dedicated hardware. Alternatively, each unit of the control device 11 may be configured with a CPU (Central Processing Unit), memory, etc., and the CPU may execute a computer program for realizing the function of each unit to realize that function.

[0023] In this embodiment, the control device 11 may be provided inside or outside, for example, any of the distributed mobile networks shown in FIG. 9 or other networks. The control device 11 including the processing unit 111 realizes a decision function and a decision device for dynamically changing the placement of NFs, and also realizes a device for executing instructions. The function of the control device 11 (e.g., the function of the processing unit 111) may be configured as a function of a new NF. In this embodiment, CORBA NF is used, and NF componentization (NF components) is applied. Therefore, in this embodiment, the NF management unit 131 may be referred to as a component management unit. The communication unit 112 corresponds to an ORB. Each NF exists, for example, on the same server or on different servers. When NFs on the same network are componentized, communication is replaced with shared memory communication.

[0024] The control device 11 acquires metrics such as NF load, the number or amount of signaling between NFs, or the computing resource capacity of each server from NFs called OAM (Operations Administration and Maintenance) or NRFs (Network Repository Functions) using the processing unit 111 (e.g., the metrics / alert management unit 132).

[0025] Fig. 2A is a diagram schematically illustrating an example of an NF management function according to an embodiment. Fig. 2B is a diagram schematically illustrating an example of a metrics / alert management function according to an embodiment. Fig. 2C is a diagram schematically illustrating an example of a scheduling function according to an embodiment. Fig. 2D is a diagram schematically illustrating an example of a component list management function according to an embodiment.

[0026] The component list management function has information indicating which NFs should be componentized. The example of FIG. 2D schematically illustrates an example of the relationship between five NFs, NF#1 to NF#5. Note that this relationship is an example for explanatory purposes and is not limited to this. In the example of FIG. 2D, NFs of the same type (e.g., NF#1 and NF#2) can be componentized. NFs that are processed consecutively (e.g., NF#1 and NF#2, NF#2 and NF#3, NF#1 and NF#4, NF#4 and NF#5) can also be componentized. On the other hand, NF#1 and NF#3, or NF#1 and NF#5, for example, do not need to be componentized. Here, componentized NFs can communicate via shared memory, while non-componentized NFs do not communicate with each other.

[0027] The NF management function (component management function in this embodiment) of the NF management unit 131 keeps track of the components deployed on a Server ID (e.g., "XXX" or "YYY"), which is an ID unique to the server, as well as the type of NF included in the component and the Instance ID, which is the ID of the NF (e.g., ID "α" for NF#1, ID "β" for NF#2, etc.). The NF management function also keeps track of the server's CR capacity (computing resource capacity). The computing resource is, for example, a CPU (Central Processing Unit) or memory. Here, in this embodiment, the contents (management table) managed by the NF management function are updated when the NF included in a component changes.

[0028] The metrics / alert management function of the metrics / alert management unit 132 periodically acquires metrics from the OAM or NRF. For example, when the metrics / alert management function observes (or predicts) that the value of each metric will be equal to or greater than a predetermined threshold X, it issues a scheduling request (alert notification) to the scheduling function to schedule how to reconfigure components so that the value of the corresponding metric will be equal to or less than threshold Y (in this embodiment, Y<X). Note that thresholds X and Y may be, for example, a single threshold for one metric, or a combination of thresholds for two or more metrics (collectively, multiple thresholds). Furthermore, when predicting that a predetermined condition related to NF will no longer be satisfied, the metrics / alert management function makes the prediction based, for example, on the transition or rate of change of the value of each metric.

[0029] As the metrics, various indicators may be used, such as the processing load of an NF, the amount of signaling between NFs, or delays related to predetermined processing. In the example of Fig. 2B, it is managed that the processing load of NF#1 (ID: α) is 70%, the processing load of NF#2 (ID: β) is 30%, the amount of signaling between NF#1 (ID: α) is 0, the amount of signaling between NF#2 (ID: α) is 0, and the amount of signaling between NF#1 (ID: α) and NF#2 (ID: β) is 1000 [kB / s].

[0030] In this way, the metrics / alert management function has a function (condition management function) for detecting when a predetermined condition related to NF is no longer satisfied. In this embodiment, an example of when the predetermined condition is no longer satisfied is when the value of each metric becomes equal to or greater than a predetermined threshold value X, but various other conditions may also be used as the predetermined condition. For example, the predetermined condition may be a condition related to the value of one metric, or a condition related to a combination of values ​​of two or more metrics.

[0031] Furthermore, in this embodiment, when a predetermined condition is no longer satisfied (for example, when the value of each metric becomes equal to or greater than a predetermined threshold X), scheduling is performed to satisfy a different condition (for example, a condition in which the value of the corresponding metric becomes equal to or less than a threshold Y) in order to satisfy the predetermined condition. Note that, as an example, when a predetermined condition is no longer satisfied (for example, when the value of each metric becomes equal to or greater than a predetermined threshold X), scheduling may be performed to satisfy the same condition (for example, a condition in which the value of the corresponding metric becomes less than the threshold X) in order to satisfy the predetermined condition.

[0032] When the scheduling function of the scheduling unit 133 receives an alert notification from the metrics / alert management function, it schedules how to rearrange the NFs included in each component so that the value of the corresponding metric becomes equal to or less than the threshold Y (i.e., changes to the NF placement). For example, the scheduling function simulates the metric values ​​of multiple rearrangement patterns for the placement of each NF in the communication system and, based on the simulation results, acquires a rearrangement pattern in which the value of the corresponding metric becomes equal to or less than the threshold Y. If two or more rearrangement patterns in which the value of the corresponding metric becomes equal to or less than the threshold Y are acquired, the scheduling function may select a rearrangement pattern according to, for example, a predetermined rule or another metric. In this embodiment, the scheduling function determines which NFs can be componentized by referring to the management contents of the component list management function. Furthermore, the scheduling function ensures that the CR capacity of each server is not exceeded when scheduling. In the example of FIG. 2C , the scheduling function is notified that the value of the corresponding metric will become equal to or less than the threshold Y by componentizing the area between NF#1 and NF#4, and performs such scheduling.

[0033] Fig. 3 is a diagram showing an example of a procedure of a process performed in the communication system P1 according to the embodiment. Fig. 4 is a diagram showing a schematic view of a process performed in the communication system P1 according to the embodiment.

[0034] In this embodiment, the communication system P1 includes a control device 11 and NF#1 to NF#5. Note that the configuration of the communication system P1 is an example for explanation purposes, and any configuration may be used as the configuration of the communication system P1.

[0035] In this embodiment, the control device 11 and NF#1 to NF#5 are CORBA NFs, each having an ORB. Each ORB also has an interface for interacting with other ORBs. This provides the interfaces and procedures for executing componentized instructions.

[0036] In the examples of Figures 3 and 4, it is assumed that, as an initial state, NF#1, NF#2, and NF#3 exist on a server with a Server ID of XXX, NF#1 and NF#2 can communicate with each other via shared memory Q1, NF#2 and NF#3 can communicate with each other via shared memory Q2, and NF#4 and NF#5 exist on a server with a Server ID of YYY, and NF#4 and NF#5 can communicate with each other via shared memory Q4. It is assumed that a problem occurs when components are configured in this initial state, and the control device 11 determines that the problem can be solved by migrating NF#1 on the server with a Server ID of XXX to a server with a Server ID of YYY. In this case, the scheduling unit 133 of the control device 11 schedules such a migration. That is, the scheduling unit 133 changes the placement of the NF by migrating it to another server.

[0037] Note that the example of Figure 3 only shows the control device 11, NF#1, NF#2, and NF#4 involved in (Process T1) to (Process T4) of this example. Furthermore, in the example of Figure 4, the control device 11 and NF#1 to NF#5 are shown with the processing unit and the communication unit (ORB) separated, and an interface is shown in the communication unit (ORB). Furthermore, in the example of Figure 4, in the initial state, NF#1 exists on a server with a Server ID of XXX. After the migration of the example of Figure 4, NF#1 has moved to a server with a Server ID of YYY, and the state in which NF#1 and NF#4 can communicate via shared memory Q3 is schematically shown.

[0038] (Process T1) In the initial state, the control device 11 instructs the ORB of NF#1 to componentize with NF#4 on the server whose Server ID is YYY. (Process T2) The ORB of NF#1 releases (decomponent) the shared memory communication with the ORB of NF#2. (Process T3) After NF#1 is migrated to the server whose Server ID is YYY, the ORB of NF#1 sets up (recomponent) for shared memory communication with the ORB of NF#4. (Process T3) Finally, NF#1 notifies the control device 11 that componentization on the server whose Server ID is YYY has been completed. In the control device 11, the NF management unit 131 receives this notification and updates the NF management table (in this embodiment, the component management table).

[0039] 5 and 6, a specific example will be shown in which the placement of a C-Plane NF in a distributed mobile network changes. Fig. 5 is a diagram showing an example of the placement of a C-Plane NF in an initial state in a distributed mobile network according to an embodiment. Fig. 6 is a diagram showing an example of the placement of a C-Plane NF in a changed state in a distributed mobile network according to an embodiment.

[0040] 5 and 6 will be used to explain an example of the behavior of the control device 11 and componentized NFs in the communication system P11. Although not shown in FIGS. 5 and 6, the control device 11 may be located in any component (e.g., on any server) in the communication system P11. In the examples of FIGS. 5 and 6, AMF, SMF, CU-CP, and Any are shown as NFs. Here, Any represents a C-Plane NF other than AMF and SMF, and may be, for example, the control device 11 or OAM. In this example, one Any corresponds to the control device 11.

[0041] The initial state shown in FIG. 5 will be described. A total of nine servers exist. Five servers (Server IDs 1 to 5) with a unit computing resource capacity (e.g., CPU or memory) of 4 are installed at central site #1. Two servers (Server IDs 6 to 7) with a unit computing resource capacity of 3 are installed at edge site #1. Two servers (Server IDs 8 to 9) with a unit computing resource capacity of 3 are installed at edge site #2. In this example, since each NF requires only one unit computing resource capacity, the server at the central site can accommodate four NFs, and the server at the edge site can accommodate three NFs. In this example, it is assumed that componentization is possible between CU-CPs, between AMFs, between SMFs, between CU-CPs and AMFs, and between AMFs and SMFs on the same server.

[0042] The state after the change shown in Fig. 6 will be described. Assume that the control device 11 observes (or predicts) via the metrics / alert management unit 132 that the amount of inter-site signaling resulting from signaling between the AMF and SMF on the server with Server ID 7 at edge site #1 and the AMF and SMF on the server with Server ID 1 and Server ID 2 at central site #1 will be equal to or greater than threshold X. That is, the control device 11 detects that the amount of signaling between central site #1 and edge site #1 will be equal to or greater than threshold X. Alternatively, the control device 11 predicts that the amount of signaling will be equal to or greater than threshold X after a predetermined period of time has elapsed. As a result, the control device 11 starts scheduling via the scheduling unit 133 to reduce the amount of signaling spanning between central site #1 and edge site #1 to be equal to or less than threshold Y.

[0043] Then, the scheduling unit 133 determines that the signaling volume will be below threshold Y by migrating and recomponenting the CU-CP on the server with Server ID 1 at central site #1 and the CU-CP on the server with Server ID 2, and the AMF and SMF on the server with Server ID 7 at edge site #1.

[0044] In this case, the control device 11 instructs the ORB of each NF via the scheduling unit 133 to decomponent the relevant NF from the existing component. As a result, each NF releases the component with the NF that is currently the component destination, and then moves to the server where the NF is to be placed. Then, each NF performs recomponenting to re-form the component. After completing the recomponenting, each NF sends a completion notification to the control device 11.

[0045] In this example, the above-mentioned (Problem 1) can be solved by the control device 11 moving the AMF from the edge site to the central site. The above-mentioned (Problem 2) can be solved by the control device 11 locating the C-Plane NF at the edge site, thereby closing the C-Plane signaling within the edge site. This reduces signaling between sites, thereby solving the problem. The above-mentioned (Problem 3) can be solved by locating the NF at the edge site to accommodate applications that require delay.

[0046] As described above, the communication system according to this embodiment includes NFs in a distributed mobile core network and a control device 11. The control device 11 includes an NF management unit 131, a condition management unit (in this embodiment, a metrics / alert management unit 132), a scheduling unit 133, and a component list management unit 134. The NF management unit 131 manages NFs. In this embodiment, the NF management unit 131 manages components, which are collections of multiple NFs. In other words, a component has an association between multiple NFs. The condition management unit detects that a predetermined condition related to an NF is not satisfied in the present or future. When the condition management unit detects that the predetermined condition is not satisfied, the scheduling unit 133 schedules a change in the placement of the NF (determines a dynamic placement of the NF) so that the predetermined condition is satisfied. The component list management unit 134 manages a list of components.

[0047] In this embodiment, the NF is separated into a communication unit having an interface and a processing unit. Each NF includes a communication unit and a processing unit. The NF performs processing to change its own location according to scheduling. In this embodiment, each NF communicates with the control device 11 via the communication unit (interface) and performs processing to change its own location (the NF) in response to instructions from the control device 11. For example, the NF performs migration processing of the NF based on various known migration techniques in response to instructions from the control device 11.

[0048] As described above, in this embodiment, each NF has a function of receiving instructions related to dynamic NF placement from the control device 11 and performing processing according to the instructions. In this embodiment, in the componentized NF, the communication unit (in this embodiment, the ORB) is provided with an interface with the control device 11. The interface receives instructions related to components, instructions related to recomponents, or instructions related to decomponents from the control device 11.

[0049] The NF has, for example, a function to receive a predetermined instruction from an external device and, upon receiving the instruction, a function to perform processing to change its own location in accordance with the instruction. The external device is not limited to, for example, the control device 11 according to this embodiment, but may be any device. In this case, the interface of the communication unit is not limited to the control device 11 according to this embodiment, but may be capable of communicating with such an external device. Here, although the present embodiment shows a case where componentization using CORBA is used, componentization using other methods may also be used.

[0050] In the communication system of this embodiment, the control device 11 can support dynamic relocation of NFs in a distributed mobile core network, thereby making it possible to satisfy evaluation indicators such as SLAs regarding processing load, signaling volume, or delay.

[0051] A second embodiment will be described. (Configuration example when normal NF is applied) A case where normal NF is applied will be described with reference to Figures 7 to 9. Note that in this example, differences from the case where CORBA according to Figures 1 to 6 is applied will be described in detail, and a detailed description of similar points will be omitted.

[0052] 7 is a diagram showing a schematic configuration example of a control device 511 corresponding to a normal NF according to an embodiment. The control device 511 includes an NF management unit 531 having an NF management function, a metrics / alarm management unit 532 having a metrics / alarm management function, and a scheduling unit 533 having a schedule function. Here, in this example, the control device 511 does not have a component list management function.

[0053] The NF management function of the NF management unit 531 manages normal NFs. When the metrics / alert management function of the metrics / alarm management unit 532 observes (or predicts) that the value of each metric will be equal to or greater than a predetermined threshold X, it issues a scheduling request to the scheduling function. In other words, the metrics / alert management function issues a scheduling request (alert notification) to the scheduling function to schedule where normal NFs should be dynamically allocated so that the value of the corresponding metric will be equal to or less than threshold Y (Y<X). When the scheduling function of the scheduling unit 533 receives an alert notification from the metrics / alert management function, it schedules how to rearrange the NFs (which NFs should be moved to which servers) so that the value of the corresponding metric will be equal to or less than threshold Y.

[0054] FIG. 8 is a diagram showing an example of a processing procedure performed in a communication system P51 according to an embodiment. FIG. 9 is a diagram showing a schematic view of a processing performed in a communication system P51 according to an embodiment. In this embodiment, the communication system P51 includes a control device 511 and NF#1 to NF#5. Note that this configuration of the communication system P51 is an example for explanation purposes, and any configuration may be used as the configuration of the communication system P51. Here, in this embodiment, the control device 511 and NF#1 to NF#5 integrate the functions of the processing unit and the communication unit.

[0055] 8 and 9, it is assumed that, as an initial state, NF#1, NF#2, and NF#3 exist on a server with a Server ID of XXX, and NF#4 and NF#5 exist on a server with a Server ID of YYY. It is assumed that a problem occurs in this initial state, and the control device 11 determines that the problem can be solved by migrating NF#1 on the server with a Server ID of XXX to the server with a Server ID of YYY. In this case, the scheduling unit 533 of the control device 511 schedules such a migration.

[0056] In the example of Fig. 8, only the control device 511 and NF#1, NF#2, and NF#4 are shown. In the example of Fig. 9, the control device 511 and NF#1 to NF#5 are illustrated. In the example of Fig. 9, NF#1 was initially located on a server with a Server ID of XXX, but after migration, a state in which NF#1 has moved to a server with a Server ID of YYY is schematically shown. In this embodiment, NFs communicate with each other via HTTP.

[0057] (Process T11) In the initial state, the control device 511 instructs NF#1 to migrate to a server whose Server ID is YYY. (Process T12) After NF#1 has migrated to the server whose Server ID is YYY, NF#1 notifies the control device 511 that the migration has been completed. In the control device 511, the NF management unit 531 receives this notification and updates the NF management table.

[0058] These interactions (instructions and completion notifications) are performed using SBI, which is a standard feature of the NF. These notifications may be performed directly from the control device 511, or may be performed via the NEF (Network Exposure Function).

[0059] <Specific Example> In the case of a normal NF, for example, by performing NF migration in a manner similar to that shown in FIGS. 5 and 6, (Problem 1), (Problem 2), and (Problem 3) can be solved.

[0060] That is, in this example, the scheduling unit 533 determines that the signaling volume will be below threshold Y by migrating the CU-CP on the server with Server ID 1 at central site #1 and the CU-CP on the server with Server ID 2, and the AMF and SMF on the server with Server ID 7 at edge site #1.

[0061] In this case, the control device 511 instructs each relevant NF to migrate to the server where it should be placed by the scheduling unit 533. After that, after the migration is completed, each relevant NF sends a completion notification to the control device 511.

[0062] As described above, in the communication system of this embodiment, in a distributed mobile core network, the control device 511 can support dynamic relocation of NFs, thereby making it possible to satisfy evaluation indicators such as SLAs regarding, for example, processing load, signaling volume, or delay.

[0063] [Regarding the above embodiment] As a result of the above, it is possible to realize an improvement in the overall service quality in, for example, a wireless network, which makes it possible to contribute to Goal 9 of the Sustainable Development Goals (SDGs) led by the United Nations, which is to "build resilient infrastructure, promote sustainable industrialization and foster innovation."

[0064] A program for implementing the functions of any of the components of any of the above-described devices may be recorded on a computer-readable recording medium and then loaded and executed by a computer system. The term "computer system" as used herein includes hardware such as an operating system or peripheral devices. Furthermore, "computer-readable recording medium" refers to portable media such as flexible disks, optical magnetic disks, ROMs, and compact disc (CD)-read-only memories (ROMs), as well as storage devices such as hard disks built into computer systems. Furthermore, "computer-readable recording medium" also includes devices that retain a program for a certain period of time, such as volatile memory within a computer system that acts as a server or client when a program is transmitted via a network such as the Internet or a communication line such as a telephone line. Such volatile memory may be, for example, random access memory (RAM). The recording medium may also be, for example, a non-transitory recording medium.

[0065] The above program may also be transmitted from a computer system storing the program in a storage device or the like to another computer system via a transmission medium or by transmission waves in the transmission medium. Here, the "transmission medium" that transmits the program refers to a medium that has the function of transmitting information, such as a network such as the Internet or a communication line such as a telephone line. The above program may also be intended to realize part of the above-mentioned functions. Furthermore, the above program may be a so-called differential file that can realize the above-mentioned functions in combination with a program already recorded in the computer system. A differential file may also be called a differential program.

[0066] Furthermore, the functions of any of the components in any of the above-described devices may be implemented by a processor. For example, each process in the embodiments may be implemented by a processor operating based on information such as a program and a computer-readable recording medium storing information such as the program. Here, the functions of each unit of the processor may be implemented by, for example, individual hardware, or may be implemented by integrated hardware. For example, the processor may include hardware, and the hardware may include at least one of a circuit for processing digital signals and a circuit for processing analog signals. For example, the processor may be configured using one or more circuit devices mounted on a circuit board, or one or both of one or more circuit elements. An integrated circuit (IC) or the like may be used as the circuit device, and a resistor or a capacitor may be used as the circuit element.

[0067] Here, the processor may be, for example, a CPU. However, the processor is not limited to a CPU, and various types of processors, such as a GPU (Graphics Processing Unit) or a DSP (Digital Signal Processor), may be used. The processor may also be, for example, a hardware circuit such as an ASIC (Application Specific Integrated Circuit). The processor may also be, for example, composed of multiple CPUs, or may also be composed of a hardware circuit such as multiple ASICs. The processor may also be, for example, composed of a combination of multiple CPUs and a hardware circuit such as multiple ASICs. The processor may also include, for example, one or more of an amplifier circuit or a filter circuit that processes analog signals.

[0068] The embodiments of this disclosure have been described in detail above with reference to the drawings, but the specific configuration is not limited to this embodiment, and includes designs within the scope that do not deviate from the gist of this disclosure.

[0069] According to the present disclosure, as an example, dynamic relocation of NFs can be supported.

[0070] 11, 511...control device, 111...processing unit, 112...communication unit, 131, 531...NF management unit, 132, 532...metrics / alert management unit (condition management unit), 133, 533...scheduling unit, 134...component list management unit, 151...interface, P1, P11, P51...communication system, Q1 to Q4...shared memory

Claims

1. A control device comprising: an NF management unit that manages NFs (Network Functions) in a distributed mobile core network; a condition management unit that detects whether a specified condition related to the NF is not satisfied currently or in the future; and a scheduling unit that, when the condition management unit detects that the specified condition is not satisfied, schedules a change in the placement of the NF so that the specified condition is satisfied.

2. The control device according to claim 1, wherein the NF is separated into a communication unit having an interface and a processing unit, the NF management unit manages a component which is a collection of a plurality of the NFs, and the control device further includes a component list management unit which manages a list of the components.

3. A communications system having a network function (NF) in a distributed mobile core network and a control device, wherein the control device comprises: an NF management unit that manages the NF; a condition management unit that detects that a specified condition related to the NF is not satisfied currently or in the future; and a scheduling unit that, when the condition management unit detects that the specified condition is not satisfied, schedules a change in the placement of the NF so that the specified condition is satisfied; and the NF performs a process of changing the placement of its own NF in accordance with the scheduling.

4. A control method, in which an NF (Network Function) management unit manages NFs in a distributed mobile core network, a condition management unit detects that a specified condition related to the NF is not satisfied at present or in the future, and a scheduling unit schedules a change in the placement of the NF so that the specified condition is satisfied when the condition management unit detects that the specified condition is not satisfied.

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