Network node and control method

Abstract

This network node comprises: a reception unit that acquires a certificate revocation list (CRL); a control unit that identifies a device in which a certificate has expired on the basis of the CRL, and identifies an opposing entity having said device as a communication destination; and a transmission unit that transmits, to the opposing entity, a setting for excluding said device from the communication destination.

Description

Network node and control method

[0001] The present invention relates to a network node and a control method in a communication system.

[0002] 3GPP (registered trademark) (3rd Generation Partnership Project) is currently studying a wireless communication system called 5G or NR (New Radio) (hereinafter, the wireless communication system will be referred to as "5G" or "NR") in order to achieve a larger system capacity, a higher data transmission speed, and a lower latency in wireless sections. Various wireless technologies are being studied for 5G to meet the requirements of achieving a throughput of 10 Gbps or more while keeping latency in wireless sections to 1 ms or less.

[0003] In NR, a network architecture including 5GC (5G Core Network) corresponding to EPC (Evolved Packet Core), which is the core network in the network architecture of LTE (Long Term Evolution), and NG-RAN (Next Generation - Radio Access Network) corresponding to E-UTRAN (Evolved Universal Terrestrial Radio Access Network), which is the RAN (Radio Access Network) in the network architecture of LTE, is being considered (for example, Non-Patent Document 1 and Non-Patent Document 2).

[0004] 3GPP TS 23.501 V18.4.0 (2023-12)3GPP TS 23.502 V18.4.0 (2023-12)Network Working Group Request for Comments: 4210, September 2005Internet Engineering Task Force Request for Comments: 8894, September 2020Internet Engineering Task Force Request for Comments: 7030, October 2013Internet Engineering Task Force Request for Comments: 9480, November 2023Internet Engineering Task Force Request for Comments: 8705, February 20203GPP TS 33.501 V18.4.0 (2023-12)

[0005] Protocols such as CMPv2 (Certificate Management Protocol) (see Non-Patent Document 3), SCEP (Simple Certificate Enrollment Protocol) (see Non-Patent Document 4), and EST (Enrollment over Secure Transport) (see Non-Patent Document 5) have been defined as mechanisms for automatically distributing certificates. When a distributed certificate expires, a CRL (Certificate Revocation List) and an OSCP (Online Certificate Status Protocol) are used. However, in environments involving a large amount of communication, the use of a CRL poses a problem of large overhead.

[0006] The present invention has been made in view of the above points, and has as its object to improve the efficiency of processes relating to certificate revocation.

[0007] According to the disclosed technology, there is provided a network node having a receiving unit that acquires a CRL (Certificate Revocation List), a control unit that identifies a device whose certificate has been revoked based on the CRL and identifies a counterpart entity that communicates with the device, and a transmitting unit that transmits to the counterpart entity a setting to exclude the device from communication destinations.

[0008] According to the disclosed technology, it is possible to improve the efficiency of processes relating to certificate revocation.

[0009] FIG. 1 is a diagram for explaining an example of a communication system. FIG. 1 is a diagram for explaining an example of a communication system in a roaming environment. FIG. 2 is a diagram for explaining an example of a PKI entity. FIG. 3 is a sequence diagram for explaining an example of certificate distribution. FIG. 4 is a diagram for explaining an example of certificate revocation. FIG. 5 is a diagram for explaining an example of certificate revocation in an embodiment of the present invention. FIG. 6 is a diagram for explaining an example of the functional configuration of a base station 10 in an embodiment of the present invention. FIG. 7 is a diagram for explaining an example of the functional configuration of a terminal 20 in an embodiment of the present invention. FIG. 8 is a diagram for explaining an example of the hardware configuration of a base station 10 and a terminal 20 in an embodiment of the present invention. FIG. 9 is a diagram for explaining an example of the configuration of a vehicle 2001 in an embodiment of the present invention.

[0010] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Note that the embodiment described below is an example, and the embodiment to which the present invention is applied is not limited to the following embodiment.

[0011] In the operation of the wireless communication system according to the embodiment of the present invention, existing technology is used as appropriate. However, the existing technology is, for example, the existing LTE, but is not limited to the existing LTE. Furthermore, the term "LTE" used in this specification has a broad meaning including LTE-Advanced, and systems subsequent to LTE-Advanced (e.g., NR), or wireless LAN (Local Area Network), unless otherwise specified.

[0012] Furthermore, in the embodiments of the present invention, "configuring" radio parameters and the like may mean that predetermined values ​​are pre-configured, or that radio parameters notified from the network node 30 or the terminal 20 are set.

[0013] Fig. 1 is a diagram illustrating an example of a communication system. As shown in Fig. 1, the communication system is composed of a UE, which is a terminal 20, and multiple network nodes 30. Hereinafter, it is assumed that one network node 30 corresponds to each function, but multiple functions may be realized by one network node 30, or multiple network nodes 30 may realize one function. Furthermore, the "connection" described below may be a logical connection or a physical connection.

[0014] The RAN (Radio Access Network) is a network node 30 having a radio access function, which may include a base station 10, and is connected to a UE, an AMF (Access and Mobility Management Function), and a UPF (User plane function). The AMF is a network node 30 having functions such as terminating the RAN interface, terminating the NAS (Non-Access Stratum), registration management, connection management, reachability management, and mobility management. The UPF is a network node 30 having functions such as a PDU (Protocol Data Unit) session point to the outside that interconnects with a DN (Data Network), packet routing and forwarding, and user plane QoS (Quality of Service) handling. The UPF and the DN constitute a network slice. In the wireless communication network according to the embodiment of the present invention, multiple network slices may be configured.

[0015] The AMF is connected to the UE, RAN, SMF (Session Management function), NSSF (Network Slice Selection Function), NEF (Network Exposure Function), NRF (Network Repository Function), UDM (Unified Data Management), AUSF (Authentication Server Function), PCF (Policy Control Function), and AF (Application Function). The AMF, SMF, NSSF, NEF, NRF, UDM, AUSF, PCF, and AF are network nodes 30 that are mutually connected via interfaces based on their respective services, Namf, Nsmf, Nnssf, Nnef, Nnrf, Nudm, Nausf, Npcf, and Naf.

[0016] The SMF is a network node 30 having functions such as session management, UE IP (Internet Protocol) address allocation and management, DHCP (Dynamic Host Configuration Protocol) function, ARP (Address Resolution Protocol) proxy, and roaming function. The NEF is a network node 30 having a function of notifying other NFs (Network Functions) of capabilities and events. The NSSF is a network node 30 having functions such as selecting a network slice to which a UE connects, determining an allowed NSSAI (Network Slice Selection Assistance Information), determining an NSSAI to be set, and determining an AMF set to which a UE connects. The PCF is a network node 30 having a function of controlling network policies. The AF is a network node 30 having a function of controlling application servers. The NRF is a network node 30 having a function of discovering NF instances that provide services. The UDM is a network node 30 that manages subscriber data and authentication data. The UDM is connected to a UDR (User Data Repository) that stores the data.

[0017] Fig. 2 is a diagram illustrating an example of a communication system in a roaming environment. As shown in Fig. 2, the network is composed of a UE, which is a terminal 20, and multiple network nodes 30. Hereinafter, it is assumed that one network node 30 corresponds to each function, but multiple functions may be realized by one network node 30, or multiple network nodes 30 may realize one function. Furthermore, the "connection" described below may be a logical connection or a physical connection.

[0018] The RAN is a network node 30 having a radio access function, and is connected to the UE, the AMF, and the UPF. The AMF is a network node 30 having functions such as RAN interface termination, NAS termination, registration management, connection management, reachability management, and mobility management. The UPF is a network node 30 having functions such as a PDU session point to the outside that interconnects with the DN, packet routing and forwarding, and user plane QoS handling. The UPF and the DN constitute a network slice. In the wireless communication network according to the embodiment of the present invention, multiple network slices are constructed.

[0019] The AMF is connected to the UE, RAN, SMF, NSSF, NEF, NRF, UDM, AUSF, PCF, AF, and SEPP (Security Edge Protection Proxy). The AMF, SMF, NSSF, NEF, NRF, UDM, AUSF, PCF, and AF are network nodes 30 that are interconnected via respective service-based interfaces, Namf, Nsmf, Nnssf, Nnef, Nnrf, Nudm, Nausf, Npcf, and Naf.

[0020] The SMF is a network node 30 having functions such as session management, UE IP address allocation and management, DHCP function, ARP proxy, and roaming function. The NEF is a network node 30 having a function of notifying other NFs of capabilities and events. The NSSF is a network node 30 having functions such as selecting a network slice to which a UE connects, determining an allowed NSSAI, determining a configured NSSAI, and determining an AMF set to which a UE connects. The PCF is a network node 30 having a function of controlling network policies. The AF is a network node 30 having a function of controlling application servers. The NRF is a network node 30 having a function of discovering NF instances that provide services. The SEPP is a non-transparent proxy that filters control plane messages between PLMNs (Public Land Mobile Networks). The vSEPP shown in FIG. 2 is a SEPP in the visited network, and the hSEPP is a SEPP in the home network.

[0021] As shown in Figure 2, a UE is in a roaming environment connected to a RAN and an AMF in a Visited PLMN (VPLMN). The VPLMN and a Home PLMN (HPLMN) are connected via a vSEPP and an hSEPP. The UE can communicate with a UDM in the HPLMN via the AMF in the VPLMN, for example.

[0022] Protocols such as CMPv2 (Certificate Management Protocol) (see Non-Patent Document 3 and Non-Patent Document 6), SCEP (Simple Certificate Enrollment Protocol) (see Non-Patent Document 4), and EST (Enrollment over Secure Transport) (see Non-Patent Document 5) have been defined as mechanisms for automatically distributing certificates. Note that CMPv2 may be written as CMP, or may correspond to any version of CMP.

[0023] Fig. 3 is a diagram for explaining an example of a PKI entity, which shows an example of a PKI entity in CMPv2 (see Non-Patent Document 3).

[0024] As shown in Fig. 3, an end entity may communicate with a registration authority (RA) (S101), a certification authority (CA) (S102), and a repository that holds certificates and certificate revocation lists (CRLs) (S103). For example, initial registration / certification, key pair recovery, key pair update, certificate update, and revocation request may be performed via S101 and S102. For example, certificate publication may be performed via S103.

[0025] 3, the registration authority may communicate with an end entity (S101), with a certification authority (S104), and with a repository that holds certificates and certificate revocation lists (S105). For example, certificate publication may be performed via S105.

[0026] 3, the certificate authority may perform communication with an end entity (S102), communication with other certificate authorities (S104), communication with a CRL issuer (S106), communication with other certificate authorities (S107), and communication with a repository that holds certificates and certificate revocation lists (S108). For example, cross-certification and cross-certificate update may be performed via S107. For example, certificate publication may be performed via S108.

[0027] 3, the CRL issuer may communicate with a certificate authority (S106) and a repository that holds certificates and certificate revocation lists (S109). For example, the CRL issuer may publish certificates and certificate revocation lists via S109.

[0028] 3, the end entity, registration authority, certification authority, CRL issuer, other certification authority, and repository that holds certificates and certificate revocation lists may each be a network node. For example, the registration authority and certification authority may be a single network node.

[0029] 4 is a sequence diagram illustrating an example of certificate distribution. In step S201, the registration authority or certification authority sends an initial authentication key (IAK) and a reference value to the end entity.

[0030] In step S202, the end entity performs key generation and creation of a certification request, and protects the request with IAK.

[0031] In step S203, the end entity sends a certification request to a registration authority or certification authority.

[0032] In step S204, the registration or certification authority verifies the request, processes the request, and creates a response.

[0033] In step S205, the registration authority or certification authority sends a certification response to the end entity.

[0034] In step S206, the end entity handles the response and creates a confirmation.

[0035] In step S207, the end entity sends a certification confirmation message to the registration authority or certification authority.

[0036] In step S208, the registration or certification authority verifies confirmation and creates a response.

[0037] In step S209, the registration authority or certification authority sends a confirmation ack to the end entity. Execution of step S209 may be optional.

[0038] In step S210, the end entity handles the response.

[0039] Here, as exemplified by Non-Patent Document 7, current systems are increasingly required to prevent tampering and verify authenticity using certificates. For example, mutual TLS (Transport Layer Security) has been defined for mutual authentication of certificates using TLS (Transport Layer Security) in the transport layer. Also, OAuth has been defined for authorization by granting certificates and privileges.

[0040] In 5G, a communication method using OAuth binding mutual TLS and certificates is also defined, as defined in, for example, Non-Patent Document 8.

[0041] In a cloud environment, devices or systems that require certificates are dynamically created or deleted, necessitating a mechanism for automatically distributing and revoking certificates. Protocols such as CMPv2, EST, and SCEP are defined for automatic certificate distribution. The mechanism for revoking certificates is defined to use CRL and / or OSCP (Online Certificate Status Protocol).

[0042] Fig. 5 is a diagram for explaining an example of certificate revocation. As shown in Fig. 5, in step 0, a certificate is distributed from a CA to a target device. In step 1, a peer entity downloads a CRL. The CRL download may be via OCSP. In step 2, the peer entity starts communication with the target device. In step 3, the target device sends a certificate to the peer entity. In step 4, the peer entity checks and verifies the revocation of the certificate.

[0043] As mentioned above, when using a CRL, there is a problem of large overhead in environments with a large amount of communication, such as telecommunications. As the number of managed nodes and the number of revoked certificates increase, the CRL list becomes enormous. Checking the CRL list every time communication is initiated, which may be tens or hundreds of times per second, causes delays in the start of communication. Also, once communication has begun between devices, there is no way to forcibly terminate communication if a CRL update occurs during communication.

[0044] FIG. 6 is a diagram illustrating an example of certificate revocation in an embodiment of the present invention. FIG. 6 shows an example of communication in an NFV (Network Function Virtualization) environment. Certificate Management Function #1 distributes Certificate Chain #1 and Certificate #1. Certificate Management Function #2 distributes Certificate Chain #2 and Certificate #2.

[0045] A network service connects a target device and a counterpart entity via a virtual link. A VNF#1 (Virtualized Network Function #1) by a target VM (Virtual Machine) or container corresponds to the target device. A VNF#2 (Virtualized Network Function #2) by a counterpart VM or container corresponds to the counterpart entity. VNF#1 and VNF#2 can communicate over a network and may send and receive certificates via TLS. NFV-MANO (Management and Orchestration) may have at least an NSD (Network Service Descriptor) and a VNFD (VNF Descriptor).

[0046] As shown in FIG. 6, in an NFV environment, NFV-MANO may manage a revocation list and notify the opposing entity of the communication destination to be revoked, thereby blocking communication until a new certificate is distributed.

[0047] Steps 0-1 and 0-2 are steps executed in advance. In step 0-1, certificate #2 is distributed in advance to VNF#1, which is the target device, and certificate chain #1, certificate chain #2, and certificate #1 are distributed in advance to VNF#2, which is the opposite entity. In step 0-2, the relationship between the communication destinations is described in the NSD, and NFV-MANO understands or stores the communication relationship between the generated device and the device. For example, in the example of FIG. 6, NFV-MANO may store that the target device VNF#1 and the opposite entity VNF#2 communicate. Furthermore, NFV-MANO may store that the communication destination of the opposite entity VNF#2 is the target device VNF#1 and that the communication destination of the target device VNF#1 is the opposite entity VNF#2. Note that NFV-MANO may generate VNF#1 of the target device and VNF#2 of the opposite entity in advance.

[0048] In step 1, certificate #2 is revoked. In step 2, NFV-MANO receives or acquires the CRL. NFV-MANO confirms that certificate #2 has been revoked based on the CRL. In step 3, NFV-MANO sets a setting to deny communication with target VNF ​​#1 to the counterpart entity VNF #2. The counterpart entity blocks communication with the target device based on the setting. If the counterpart entity is currently communicating with the target device, it may interrupt the communication, and may further exclude the target device from its communication destinations. If the counterpart entity is not currently communicating with the target device, it may exclude the target device from its communication destinations.

[0049] By using NFV-MANO and interpreting the CRL, if the certificate of the target device has been revoked, NFV-MANO extracts the opposite entity from the communication relationship managed by the NSD and NFV-MANO, and inputs a setting to the opposite entity to exclude the target device from the opposite entity's communication destinations. NFV-MANO may also send the setting to the opposite entity.

[0050] As a method for excluding communication destinations, an Access Control List (ACL) may be used, or the certificate of the target device may be excluded from known certificates. The CRL may be received by the NFV-MANO, or may be received by the Certificate Management Function (CMF) and a certificate status change notification may be sent to the NFV-MANO.

[0051] The NFV-MANO may clean up the registration of the certificate of the target device when the certificate is revoked. The NFV-MANO may delete the certificate of the target device and the registration of the certificate in the Authorization Server. The NFV-MANO may change the Virtual Link (VL) in the NFV-MANO or the VL between the target device and the counterpart entity to indicate that communication is temporarily unavailable. The NFV-MANO may notify the associated maintenance device that the target device and the counterpart entity cannot communicate.

[0052] By redistributing the certificate, the NFV-MANO may allow the opposite entity and the target device to resume communication. The NFV-MANO may send a setting to the opposite entity that allows the resumption of communication. The NFV-MANO may re-register the target device and the target device's certificate with the authorization server. The NFV-MANO may return the VL within the NFV-MANO or the VL between the target device and the opposite entity to a normal state.

[0053] The above-described embodiment can reduce the amount of CRL acquisition or interaction processing with OCSP and the amount of communication. It can also shorten the time from when a certificate is revoked until the use of the revoked certificate is restricted. It can also block communications that use revoked certificates. Since the automated processing by NFV-MANO is incorporated into existing operational procedures, it is possible to localize operational changes. It can also control the period from when communications are blocked due to certificate revocation until when communications are resumed due to the issuance of a new certificate, thereby achieving communication control through certificate control.

[0054] That is, the efficiency of the process relating to certificate revocation can be improved.

[0055] (Device Configuration) Next, a description will be given of an example of the functional configuration of the base station 10, network node 30, and terminal 20 that perform the processes and operations described above. The base station 10, network node 30, and terminal 20 include functions for performing the above-described embodiments. However, the base station 10, network node 30, and terminal 20 may each include only a part of the functions of the embodiments.

[0056] <Base Station 10 and Network Node 30> Fig. 7 is a diagram showing an example of the functional configuration of the base station 10. As shown in Fig. 7, the base station 10 has a transmitting unit 110, a receiving unit 120, a setting unit 130, and a control unit 140. The functional configuration shown in Fig. 7 is merely an example. As long as the operations according to the embodiment of the present invention can be performed, the names of the functional divisions and functional units may be any. Note that the network node 30 may have the same functional configuration as the base station 10. Furthermore, a network node 30 having multiple different functions in the system architecture may be composed of multiple network nodes 30 separated by function.

[0057] The transmitter 110 includes a function of generating a signal to be transmitted to the terminal 20 or another network node 30 and transmitting the signal by wire or wirelessly. The receiver 120 includes a function of receiving various signals transmitted from the terminal 20 or another network node 30 and acquiring, for example, information of a higher layer from the received signal.

[0058] The setting unit 130 stores preset setting information and various setting information to be transmitted to the terminal 20 in a storage device, and reads the information from the storage device as needed. The content of the setting information includes, for example, settings related to the operations described in the embodiments.

[0059] As described in the embodiments, the control unit 140 performs processing related to the operations described in the embodiments. The control unit 140 also performs processing related to communication with the terminal 20. A functional unit related to signal transmission in the control unit 140 may be included in the transmitting unit 110, and a functional unit related to signal reception in the control unit 140 may be included in the receiving unit 120.

[0060] <Terminal 20> Fig. 8 is a diagram showing an example of the functional configuration of the terminal 20. As shown in Fig. 8, the terminal 20 has a transmitting unit 210, a receiving unit 220, a setting unit 230, and a control unit 240. The functional configuration shown in Fig. 8 is merely an example. The names of the functional divisions and functional units may be any as long as they can perform the operations related to the embodiment of the present invention.

[0061] The transmitter 210 creates a transmission signal from the transmission data and transmits the transmission signal wirelessly. The receiver 220 receives various signals wirelessly and acquires higher layer signals from the received physical layer signals. The receiver 220 also has a function of receiving NR-PSS, NR-SSS, NR-PBCH, DL / UL control signals, reference signals, etc. transmitted from the network node 30.

[0062] The setting unit 230 stores various setting information received from the network node 30 by the receiving unit 220 in a storage device and reads it from the storage device as needed. The setting unit 230 also stores setting information that is set in advance. The content of the setting information is, for example, settings related to the operations described in the embodiments.

[0063] The control unit 240 performs processing related to the operations described in the embodiments as described in the embodiments. The control unit 240 also performs processing related to the capacity-enhanced cell. The function unit related to signal transmission in the control unit 240 may be included in the transmitting unit 210, and the function unit related to signal reception in the control unit 240 may be included in the receiving unit 220.

[0064] (Hardware Configuration) The block diagrams (FIGS. 7 and 8) used to explain the above embodiments show functional blocks. These functional blocks (components) are realized by any combination of at least one of hardware and software. Furthermore, the method for realizing each functional block is not particularly limited. That is, each functional block may be realized using a single device that is physically or logically coupled, or may be realized using two or more physically or logically separated devices that are directly or indirectly connected (for example, using wires, wirelessly, etc.) and these multiple devices. The functional block may also be realized by combining software with the single device or the multiple devices.

[0065] Functions include, but are not limited to, judgment, determination, assessment, calculation, computation, processing, derivation, investigation, search, confirmation, reception, transmission, output, access, resolution, selection, selection, establishment, comparison, assumption, expectation, consideration, broadcasting, notifying, communicating, forwarding, configuring, reconfiguring, allocating, mapping, and assignment. For example, a functional block (component) that performs transmission is called a transmitting unit or transmitter. As mentioned above, there are no particular limitations on how these functions are implemented.

[0066] For example, the network node 30, the terminal 20, etc. according to an embodiment of the present disclosure may function as a computer that performs processing of the wireless communication method of the present disclosure. Fig. 9 is a diagram illustrating an example of the hardware configuration of the base station 10 and the terminal 20 according to an embodiment of the present disclosure. The network node 30 may have the same hardware configuration as the base station 10. The above-described base station 10 and the terminal 20 may be physically configured as a computer device including a processor 1001, a storage device 1002, an auxiliary storage device 1003, a communication device 1004, an input device 1005, an output device 1006, a bus 1007, etc.

[0067] In the following description, the term "apparatus" can be interpreted as a circuit, a device, a unit, etc. The hardware configuration of the base station 10 and the terminal 20 may be configured to include one or more of the apparatuses shown in the drawings, or may be configured to exclude some of the apparatuses.

[0068] Each function in the base station 10 and the terminal 20 is realized by loading specified software (programs) onto hardware such as the processor 1001, the memory device 1002, etc., so that the processor 1001 performs calculations, controls communication by the communication device 1004, and controls at least one of reading and writing data in the memory device 1002 and the auxiliary memory device 1003.

[0069] The processor 1001 controls the entire computer by running, for example, an operating system. The processor 1001 may be configured as a central processing unit (CPU) including an interface with peripheral devices, a control device, an arithmetic unit, a register, etc. For example, the above-mentioned control unit 140, control unit 240, etc. may be realized by the processor 1001.

[0070] The processor 1001 also reads programs (program codes), software modules, data, etc. from at least one of the auxiliary storage device 1003 and the communication device 1004 into the storage device 1002 and executes various processes in accordance with the programs. The programs used are those that cause a computer to execute at least some of the operations described in the above-described embodiments. For example, the control unit 140 of the base station 10 shown in FIG. 7 may be implemented by a control program stored in the storage device 1002 and running on the processor 1001. For example, the control unit 240 of the terminal 20 shown in FIG. 8 may be implemented by a control program stored in the storage device 1002 and running on the processor 1001. While the above-described various processes have been described as being executed by one processor 1001, they may also be executed simultaneously or sequentially by two or more processors 1001. The processor 1001 may be implemented by one or more chips. The programs may also be transmitted from a network via a telecommunications line.

[0071] The storage device 1002 is a computer-readable recording medium and may be configured, for example, by at least one of a read-only memory (ROM), an erasable programmable read-only memory (EPROM), an electrically erasable programmable read-only memory (EEPROM), a random access memory (RAM), etc. The storage device 1002 may also be called a register, a cache, a main memory, etc. The storage device 1002 can store executable programs (program codes), software modules, etc. for implementing a communication method according to an embodiment of the present disclosure.

[0072] The secondary storage device 1003 is a computer-readable recording medium, and may be, for example, at least one of an optical disk such as a CD-ROM (Compact Disc ROM), a hard disk drive, a flexible disk, a magneto-optical disk (e.g., a compact disk, a digital versatile disk, a Blu-ray (registered trademark) disk), a smart card, a flash memory (e.g., a card, a stick, a key drive), a floppy (registered trademark) disk, a magnetic strip, etc. The above-mentioned storage medium may be, for example, a database, a server, or other appropriate medium including at least one of the storage device 1002 and the secondary storage device 1003.

[0073] The communication device 1004 is hardware (transmission / reception device) for communicating between computers via at least one of a wired network and a wireless network, and is also referred to as, for example, a network device, a network controller, a network card, a communication module, etc. The communication device 1004 may be configured to include a high-frequency switch, a duplexer, a filter, a frequency synthesizer, etc. to realize at least one of frequency division duplex (FDD) and time division duplex (TDD). For example, a transmission / reception antenna, an amplifier unit, a transmission / reception unit, a transmission path interface, etc. may be realized by the communication device 1004. The transmission / reception unit may be implemented as a transmission unit and a reception unit that are physically or logically separated.

[0074] The input device 1005 is an input device (e.g., a keyboard, a mouse, a microphone, a switch, a button, a sensor, etc.) that receives input from the outside. The output device 1006 is an output device (e.g., a display, a speaker, an LED lamp, etc.) that outputs to the outside. Note that the input device 1005 and the output device 1006 may be integrated into one device (e.g., a touch panel).

[0075] Furthermore, each device such as the processor 1001 and the storage device 1002 is connected by a bus 1007 for communicating information. The bus 1007 may be configured using a single bus, or may be configured using different buses between each device.

[0076] Furthermore, the base station 10 and the terminal 20 may be configured to include hardware such as a microprocessor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a programmable logic device (PLD), or a field programmable gate array (FPGA), and some or all of the functional blocks may be realized by the hardware. For example, the processor 1001 may be implemented using at least one of these pieces of hardware.

[0077] Fig. 10 shows an example configuration of a vehicle 2001. As shown in Fig. 10, the vehicle 2001 includes a drive unit 2002, a steering unit 2003, an accelerator pedal 2004, a brake pedal 2005, a shift lever 2006, front wheels 2007, rear wheels 2008, an axle 2009, an electronic control unit 2010, various sensors 2021 to 2029, an information service unit 2012, and a communication module 2013. Each aspect / embodiment described in the present disclosure may be applied to a communication device mounted on the vehicle 2001, and may be applied to the communication module 2013, for example.

[0078] The drive unit 2002 is configured, for example, by an engine, a motor, or a hybrid of an engine and a motor. The steering unit 2003 includes at least a steering wheel (also called a handle) and is configured to steer at least one of the front wheels and the rear wheels based on the operation of the steering wheel operated by the user.

[0079] The electronic control unit 2010 is composed of a microprocessor 2031, a memory (ROM, RAM) 2032, and a communication port (IO port) 2033. Signals are input to the electronic control unit 2010 from various sensors 2021 to 2029 provided in the vehicle 2001. The electronic control unit 2010 may also be called an ECU (Electronic Control Unit).

[0080] The signals from the various sensors 2021 to 2029 include a current signal from a current sensor 2021 that senses the current of the motor, a rotation speed signal of the front and rear wheels obtained by a rotation speed sensor 2022, an air pressure signal of the front and rear wheels obtained by an air pressure sensor 2023, a vehicle speed signal obtained by a vehicle speed sensor 2024, an acceleration signal obtained by an acceleration sensor 2025, an accelerator pedal depression amount signal obtained by an accelerator pedal sensor 2029, a brake pedal depression amount signal obtained by a brake pedal sensor 2026, a shift lever operation signal obtained by a shift lever sensor 2027, and a detection signal for detecting obstacles, vehicles, pedestrians, etc. obtained by an object detection sensor 2028.

[0081] The information service unit 2012 is composed of various devices, such as a car navigation system, an audio system, speakers, a television, and a radio, for providing various types of information such as driving information, traffic information, and entertainment information, and one or more ECUs for controlling these devices. The information service unit 2012 provides various types of multimedia information and multimedia services to the occupants of the vehicle 2001 by using information acquired from external devices via the communication module 2013, etc.

[0082] The driving assistance system unit 2030 is composed of various devices that provide functions for preventing accidents and reducing the driving burden on the driver, such as millimeter-wave radar, LiDAR (Light Detection and Ranging), cameras, positioning locators (e.g., GNSS, etc.), map information (e.g., high-definition (HD) maps, autonomous vehicle (AV) maps, etc.), gyro systems (e.g., IMU (Inertial Measurement Unit), INS (Inertial Navigation System), etc.), AI (Artificial Intelligence) chips, and AI processors, as well as one or more ECUs that control these devices. In addition, the driving assistance system unit 2030 transmits and receives various information via the communication module 2013 to realize the driving assistance function or the autonomous driving function.

[0083] The communication module 2013 can communicate with the microprocessor 2031 and components of the vehicle 2001 via the communication port. For example, the communication module 2013 transmits and receives data via the communication port 2033 to and from the drive unit 2002, steering unit 2003, accelerator pedal 2004, brake pedal 2005, shift lever 2006, front wheels 2007, rear wheels 2008, axle 2009, microprocessor 2031 and memory (ROM, RAM) 2032 in the electronic control unit 2010, and sensors 2021 to 29, which are provided in the vehicle 2001.

[0084] The communication module 2013 is a communication device that can be controlled by the microprocessor 2031 of the electronic control unit 2010 and can communicate with an external device. For example, it transmits and receives various information to and from the external device via wireless communication. The communication module 2013 may be located either inside or outside the electronic control unit 2010. The external device may be, for example, a base station, a mobile station, or the like.

[0085] The communication module 2013 transmits, via wireless communication to an external device, a current signal from the current sensor that is input to the electronic control unit 2010. The communication module 2013 also transmits, via wireless communication to an external device, the rotation speed signals of the front and rear wheels acquired by a rotation speed sensor 2022, the air pressure signals of the front and rear wheels acquired by an air pressure sensor 2023, the vehicle speed signal acquired by a vehicle speed sensor 2024, the acceleration signal acquired by an acceleration sensor 2025, the accelerator pedal depression amount signal acquired by an accelerator pedal sensor 2029, the brake pedal depression amount signal acquired by a brake pedal sensor 2026, the shift lever operation signal acquired by a shift lever sensor 2027, and detection signals for detecting obstacles, vehicles, pedestrians, etc. acquired by an object detection sensor 2028, all of which are input to the electronic control unit 2010.

[0086] The communication module 2013 receives various information (traffic information, traffic signal information, vehicle distance information, etc.) transmitted from external devices and displays it on the information service unit 2012 provided in the vehicle 2001. The communication module 2013 also stores the various information received from the external devices in a memory 2032 that can be used by the microprocessor 2031. Based on the information stored in the memory 2032, the microprocessor 2031 may control the drive unit 2002, steering unit 2003, accelerator pedal 2004, brake pedal 2005, shift lever 2006, front wheels 2007, rear wheels 2008, axles 2009, sensors 2021 to 2029, etc. provided in the vehicle 2001.

[0087] (Summary of the embodiment) As described above, according to the embodiment of the present invention, there is provided a network node having a receiving unit that acquires a CRL (Certificate Revocation List), a control unit that identifies a device whose certificate has been revoked based on the CRL and identifies a counterpart entity that communicates with the device, and a transmitting unit that transmits to the counterpart entity a setting to exclude the device from communication destinations.

[0088] The above configuration makes it possible to reduce the amount of CRL acquisition or interaction processing with OCSP, as well as the amount of communication. It also shortens the time between the revocation of a certificate and the suppression of use of the revoked certificate. It also makes it possible to block communications using revoked certificates. Furthermore, since the automated processing by NFV-MANO is incorporated into existing operational procedures, it is possible to localize operational changes. It also makes it possible to control the period from the blocking of communications due to certificate revocation to the resumption of communications due to the issuance of a new certificate, thereby realizing communication control through certificate control. In other words, it is possible to improve the efficiency of processing related to certificate revocation.

[0089] The control unit may delete the certificate of the device in the authorization server. This configuration can reduce the amount of communication and the need for CRL acquisition or interaction with OCSP.

[0090] The control unit may change the VL (Virtual Link) between the device and the counterpart entity to indicate that communication is temporarily unavailable. This configuration can reduce the amount of CRL acquisition or interaction processing with OCSP and the amount of communication. It can also shorten the time from when a certificate is revoked to when the use of the revoked certificate is restricted.

[0091] The control unit may allow the resumption of communication between the device and the counterpart entity when the certificate of the device is redistributed. With this configuration, it is possible to control the period from when communication is blocked due to the certificate expiration until when communication is resumed due to the issuance of a new certificate, thereby realizing communication control through certificate control.

[0092] When the certificate of the device is redistributed, the control unit may change the VL (Virtual Link) between the device and the counterpart entity to indicate that communication is possible. With this configuration, it is possible to control the period from when communication is blocked due to the certificate expiration to when communication is resumed due to the issuance of a new certificate, thereby realizing communication control through certificate control.

[0093] Furthermore, according to an embodiment of the present invention, there is provided a control method in which a network node executes the following procedures: a procedure for acquiring a CRL (Certificate Revocation List); a procedure for identifying a device whose certificate has been revoked based on the CRL, a procedure for identifying a counterpart entity that communicates with the device; and a procedure for transmitting a setting to the counterpart entity to exclude the device from communication destinations.

[0094] The above configuration makes it possible to reduce the amount of CRL acquisition or interaction processing with OCSP, as well as the amount of communication. It also shortens the time between the revocation of a certificate and the suppression of use of the revoked certificate. It also makes it possible to block communications using revoked certificates. Furthermore, since the automated processing by NFV-MANO is incorporated into existing operational procedures, it is possible to localize operational changes. It also makes it possible to control the period from the blocking of communications due to certificate revocation to the resumption of communications due to the issuance of a new certificate, thereby realizing communication control through certificate control. In other words, it is possible to improve the efficiency of processing related to certificate revocation.

[0095] (Supplementary Notes on the Embodiments) Although the embodiments of the present invention have been described above, the disclosed invention is not limited to such embodiments, and those skilled in the art will understand various modifications, alterations, alternatives, and substitutions. While specific numerical examples have been used to facilitate understanding of the invention, unless otherwise specified, these numerical values ​​are merely examples, and any appropriate values ​​may be used. The division of items in the above description is not essential to the present invention. Two or more items may be used in combination as needed, and items described in one item may apply to items described in another item (as long as there is no contradiction). Boundaries between functional units or processing units in functional block diagrams do not necessarily correspond to physical component boundaries. The operations of multiple functional units may be physically performed by a single component, or the operations of a single functional unit may be physically performed by multiple components. The order of processing steps described in the embodiments may be reversed as long as there is no contradiction. For convenience of processing description, the network node 30 and the terminal 20 have been described using functional block diagrams. However, such devices may be realized by hardware, software, or a combination thereof. The software operated by the processor of the network node 30 in accordance with an embodiment of the present invention and the software operated by the processor of the terminal 20 in accordance with an embodiment of the present invention may each be stored in any suitable storage medium, such as random access memory (RAM), flash memory, read-only memory (ROM), EPROM, EEPROM, registers, hard disk (HDD), removable disk, CD-ROM, database, server, or the like.

[0096] Furthermore, the notification of information is not limited to the aspects / embodiments described in the present disclosure, and may be performed using other methods. For example, the notification of information may be performed by physical layer signaling (e.g., Downlink Control Information (DCI), Uplink Control Information (UCI)), higher layer signaling (e.g., Radio Resource Control (RRC) signaling, Medium Access Control (MAC) signaling), broadcast information (Master Information Block (MIB), System Information Block (SIB)), other signals, or a combination thereof. Furthermore, the RRC signaling may be referred to as an RRC message, and may be, for example, an RRC Connection Setup message, an RRC Connection Reconfiguration message, or the like.

[0097] Each aspect / embodiment described in the present disclosure may be applied to at least one of systems using LTE (Long Term Evolution), LTE-Advanced (LTE-A), SUPER 3G, IMT-Advanced, 4G (4th generation mobile communication system), 5G (5th generation mobile communication system), FRA (Future Radio Access), NR (New Radio), W-CDMA (registered trademark), GSM (registered trademark), CDMA2000, UMB (Ultra Mobile Broadband), IEEE 802.11 (Wi-Fi (registered trademark)), IEEE 802.16 (WiMAX (registered trademark)), IEEE 802.20, UWB (Ultra-Wide Band), Bluetooth (registered trademark), or other suitable systems, and next-generation systems enhanced based on these. Furthermore, a combination of multiple systems (e.g., a combination of at least one of LTE and LTE-A with 5G, etc.) may also be applied.

[0098] Each aspect / embodiment described in the present disclosure may be implemented using any of the following standards: LTE (Long Term Evolution), LTE-Advanced (LTE-A), SUPER 3G, IMT-Advanced, 4G (4th generation mobile communication system), 5G (5th generation mobile communication system), 6th generation mobile communication system (6G), xth generation mobile communication system (xG) (xG (x is, for example, an integer or a decimal number)), FRA (Future Radio Access), NR (new Radio), New radio access (NX), Future generation radio access (FX), W-CDMA (registered trademark), GSM (registered trademark), CDMA2000, UMB (Ultra Mobile Broadband), IEEE 802.11 (Wi-Fi (registered trademark)), IEEE 802.16 (WiMAX (registered trademark)), IEEE 802.17 (WiMAX (registered trademark)), IEEE 802.19 (WiMAX (registered trademark)), IEEE 802.20 (WiMAX (registered trademark)), IEEE 802.21 (Wi-Fi (registered trademark)), IEEE 802.22 (WiMAX (registered trademark)), IEEE 802.23 (WiMAX (registered trademark)), IEEE 802.24 (WiMAX (registered trademark)), IEEE 802.25 (WiMAX (registered trademark)), IEEE 802.26 (WiMAX (registered trademark)), IEEE 802.27 (WiMAX (registered trademark)), IEEE 802.28 (WiMAX (registered trademark)), IEEE 802.29 (WiMAX (registered trademark)), IEEE 802.30 (WiMAX (registered trademark)), IEEE 802.31 (Wi-Fi (registered trademark)), IEEE 802.32 (WiMAX (registered trademark)), IEEE 802.33 (WiMAX (registered trademark)), IEEE 802.34 ( The present invention may be applied to at least one of systems using 802.20, UWB (Ultra-Wide Band), Bluetooth (registered trademark), or other suitable systems, and next-generation systems that are extended, modified, created, or defined based on these systems. The present invention may also be applied to a combination of multiple systems (e.g., a combination of LTE and / or LTE-A with 5G).

[0099] The order of the procedures, sequences, flowcharts, etc. of each aspect / embodiment described herein may be rearranged unless it is consistent. For example, the methods described in this disclosure present elements of various steps using an example order and are not limited to the particular order presented.

[0100] In this specification, a specific operation that is described as being performed by the network node 30 may also be performed by its upper node in some cases. In a network consisting of one or more network nodes including the network node 30, it is clear that various operations performed for communication with the terminal 20 may be performed by at least one of the network node 30 and another network node other than the network node 30 (for example, an MME or an S-GW, etc., are possible, but are not limited to these). Although the above example illustrates a case where there is one other network node other than the network node 30, the other network node may be a combination of multiple other network nodes (for example, an MME and an S-GW).

[0101] The information, signals, etc. described in the present disclosure may be output from a higher layer (or a lower layer) to a lower layer (or a higher layer), or may be input / output via multiple network nodes.

[0102] Input and output information may be stored in a specific location (for example, memory) or may be managed using a management table. Input and output information may be overwritten, updated, or added to. Output information may be deleted. Input information may be sent to another device.

[0103] In the present disclosure, the determination may be made by a value represented by one bit (0 or 1), by a Boolean value (true or false), or by a comparison of numerical values ​​(e.g., comparison with a predetermined value).

[0104] Software shall be construed broadly to mean instructions, instruction sets, code, code segments, program code, programs, subprograms, software modules, applications, software applications, software packages, routines, subroutines, objects, executable files, threads of execution, procedures, functions, etc., whether referred to as software, firmware, middleware, microcode, hardware description language, or otherwise.

[0105] Software, instructions, information, etc. may also be transmitted or received over a transmission medium. For example, if software is transmitted from a website, server, or other remote source using wired technologies (such as coaxial cable, fiber optic cable, twisted pair, Digital Subscriber Line (DSL)), and / or wireless technologies (such as infrared, microwave), then these wired and / or wireless technologies are included within the definition of transmission media.

[0106] The information, signals, etc. described in this disclosure may be represented using any of a variety of different technologies. For example, data, instructions, commands, information, signals, bits, symbols, chips, etc. that may be referred to throughout the above description may be represented by voltages, currents, electromagnetic waves, magnetic fields or magnetic particles, optical fields or photons, or any combination thereof.

[0107] Note that terms described in this disclosure and terms necessary for understanding this disclosure may be replaced with terms having the same or similar meanings. For example, at least one of a channel and a symbol may be a signal (signaling). Furthermore, a signal may be a message. Furthermore, a component carrier (CC) may be called a carrier frequency, a cell, a frequency carrier, etc.

[0108] As used in this disclosure, the terms "system" and "network" are used interchangeably.

[0109] Furthermore, the information, parameters, etc. described in the present disclosure may be expressed using absolute values, may be expressed using relative values ​​from a predetermined value, or may be expressed using other corresponding information. For example, a radio resource may be indicated by an index.

[0110] The names used for the above-described parameters are not intended to be limiting in any way. Furthermore, the mathematical expressions using these parameters may differ from those explicitly disclosed in this disclosure. The various channels (e.g., PUCCH, PDCCH, etc.) and information elements may be identified by any suitable names, and therefore the various names assigned to these various channels and information elements are not intended to be limiting in any way.

[0111] In the present disclosure, terms such as "base station (BS)," "radio base station," "base station device," "fixed station," "NodeB," "eNodeB (eNB)," "gNodeB (gNB)," "access point," "transmission point," "reception point," "transmission / reception point," "cell," "sector," "cell group," "carrier," and "component carrier" may be used interchangeably. A base station may also be referred to by terms such as a macrocell, a small cell, a femtocell, and a picocell.

[0112] A base station can accommodate one or more (e.g., three) cells. When a base station accommodates multiple cells, the overall coverage area of ​​the base station can be partitioned into multiple smaller areas, and each smaller area can also be provided with communication services by a base station subsystem (e.g., a small indoor base station (RRH: Remote Radio Head)). The terms "cell" or "sector" refer to part or all of the coverage area of ​​a base station and / or base station subsystem that provides communication services within that coverage.

[0113] In this disclosure, the terms "Mobile Station (MS)," "user terminal," "User Equipment (UE)," "terminal," and the like may be used interchangeably.

[0114] A mobile station may also be referred to by those skilled in the art as a subscriber station, mobile unit, subscriber unit, wireless unit, remote unit, mobile device, wireless device, wireless communication device, remote device, mobile subscriber station, access terminal, mobile terminal, wireless terminal, remote terminal, handset, user agent, mobile client, client, or some other suitable terminology.

[0115] At least one of the base station and the mobile station may be referred to as a transmitting device, a receiving device, a communication device, etc. At least one of the base station and the mobile station may be a device mounted on a mobile body, the mobile body itself, etc. The mobile body may be a vehicle (e.g., a car, an airplane, etc.), an unmanned mobile body (e.g., a drone, an autonomous vehicle, etc.), or a robot (manned or unmanned). At least one of the base station and the mobile station may also include devices that do not necessarily move during communication operations. For example, at least one of the base station and the mobile station may be an IoT (Internet of Things) device such as a sensor.

[0116] Furthermore, a base station in the present disclosure may be read as a user terminal. For example, the aspects / embodiments of the present disclosure may be applied to a configuration in which communication between a base station and a user terminal is replaced with communication between multiple terminals 20 (which may be called, for example, Device-to-Device (D2D) or Vehicle-to-Everything (V2X)). In this case, the terminal 20 may be configured to have the functions of the above-described network node 30. Furthermore, terms such as "uplink" and "downlink" may be read as terms corresponding to terminal-to-terminal communication (for example, "side"). For example, terms such as an uplink channel and a downlink channel may be read as a side channel.

[0117] Similarly, the user terminal in the present disclosure may be read as a base station, in which case the base station may be configured to have the functions of the user terminal described above.

[0118] As used in this disclosure, the terms "determining" and "determining" may encompass a wide variety of actions. "Determining" and "determining" may include, for example, judging, calculating, computing, processing, deriving, investigating, looking up, searching, inquiring (e.g., searching in a table, database, or other data structure), ascertaining, and the like. "Determining" and "determining" may also include receiving (e.g., receiving information), transmitting (e.g., sending information), input, output, accessing (e.g., accessing data in memory), and the like. Furthermore, "judgment" and "decision" can include regarding resolving, selecting, choosing, establishing, comparing, etc. as having been "judged" or "decided." In other words, "judgment" and "decision" can include regarding some action as having been "judged" or "decided." Furthermore, "judgment (decision)" can be interpreted as "assuming," "expecting," "considering," etc.

[0119] The terms "connected," "coupled," or any variation thereof, refer to any direct or indirect connection or coupling between two or more elements, and may include the presence of one or more intermediate elements between two elements that are "connected" or "coupled" to each other. The coupling or connection between elements may be physical, logical, or a combination thereof. For example, "connected" may be read as "access." As used in this disclosure, two elements may be considered to be "connected" or "coupled" to each other using one or more wires, cables, and / or printed electrical connections, as well as electromagnetic energy having wavelengths in the radio frequency range, microwave range, and optical (both visible and invisible) range, as some non-limiting and non-exhaustive examples.

[0120] The reference signal may be abbreviated as RS (Reference Signal) or may be called a pilot depending on the applicable standard.

[0121] As used in this disclosure, the phrase "based on" does not mean "based only on," unless expressly stated otherwise. In other words, the phrase "based on" means both "based only on" and "based at least on."

[0122] As used in this disclosure, any reference to an element using a designation such as "first," "second," etc. does not generally limit the quantity or order of those elements. These designations may be used in this disclosure as a convenient method of distinguishing between two or more elements. Thus, a reference to a first and a second element does not imply that only two elements may be employed or that the first element must in some way precede the second element.

[0123] The "means" in the configuration of each of the above devices may be replaced with "part," "circuit," "device," etc.

[0124] When the terms "include," "including," and variations thereof are used in this disclosure, these terms are intended to be inclusive, similar to the term "comprising." Furthermore, when the term "or" is used in this disclosure, it is not intended to be an exclusive or.

[0125] In this disclosure, where articles are added by translation, such as a, an, and the in English, the disclosure may include that the nouns following these articles are in the plural form.

[0126] In the present disclosure, the term "A and B are different" may mean "A and B are different from each other." The term may also mean "A and B are each different from C." Terms such as "separate" and "coupled" may also be interpreted in the same way as "different."

[0127] The aspects / embodiments described in this disclosure may be used alone, in combination, or switched depending on the implementation. Notification of predetermined information (e.g., notification that "X is true") is not limited to explicit notification, but may be implicit (e.g., not notifying the predetermined information).

[0128] Although the present disclosure has been described in detail above, it is clear to those skilled in the art that the present disclosure is not limited to the embodiments described herein. The present disclosure can be implemented in modified and altered forms without departing from the spirit and scope of the present disclosure as defined by the claims. Therefore, the description of the present disclosure is intended to be illustrative and does not have any limiting meaning on the present disclosure.

[0129] 10 Base station 110 Transmitter 120 Receiver 130 Setting unit 140 Control unit 20 Terminal 210 Transmitter 220 Receiver 230 Setting unit 240 Control unit 30 Network node 1001 Processor 1002 Storage device 1003 Auxiliary storage device 1004 Communication device 1005 Input device 1006 Output device 2001 Vehicle 2002 Drive unit 2003 Steering unit 2004 Accelerator pedal 2005 Brake pedal 2006 Shift lever 2007 Front wheels 2008 Rear wheels 2009 Axle 2010 Electronic control unit 2012 Information service unit 2013 Communication module 2021 Current sensor 2022 RPM sensor 2023 Tire pressure sensor 2024 Vehicle speed sensor 2025 Acceleration sensor 2026 Brake pedal sensor 2027 Shift lever sensor 2028 Object detection sensor 2029 Accelerator pedal sensor 2030 Driving assistance system unit 2031 Microprocessor 2032 Memory (ROM, RAM) 2033 Communication port (IO port)

Claims

1. A network node having a receiving unit that acquires a CRL (Certificate Revocation List), a control unit that identifies a device whose certificate has been revoked based on the CRL and identifies a counterpart entity that communicates with the device, and a transmitting unit that transmits settings to the counterpart entity that exclude the device from communication destinations.

2. The network node according to claim 1, wherein the control unit deletes the certificate of the device in the authorization server.

3. The network node according to claim 1, wherein said control unit changes a VL (Virtual Link) between said device and said counterpart entity to indicate that communication is temporarily unavailable.

4. The network node according to claim 1, wherein the control unit allows the device to resume communication with the counterpart entity when the certificate of the device is redistributed.

5. A network node according to claim 1, wherein the control unit changes the VL (Virtual Link) between the device and the opposing entity to indicate that communication is possible when the device's certificate is redistributed.

6. A control method in which a network node executes the following procedures: acquiring a CRL (Certificate Revocation List); identifying a device whose certificate has expired based on the CRL and identifying a counterpart entity that communicates with the device; and sending a setting to the counterpart entity that excludes the device from communication destinations.

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