DS-tt device, 5g system, UE, and message conversion method

Abstract

A user equipment (UE) (40) in a 5 Generation System (5GS) (100) establishes a packet data unit (PDU) session (60) together with a user plane function (UPF) device (20), the session being such that information pertaining to both internet protocol (IP) PDU and Ethernet PDU can be stored. A device-side time-sensitive networking translator (DS-TT) device (50) converts the content in the message body of a precision time protocol (PTP) message, which is received via the PDU session (60), in accordance with a combination of the data type of the PTP message and the data type of the transmission destination of the PTP message.

Description

DS-TT device, 5G system, UE, and message conversion method

[0001] The present disclosure relates to a time synchronization protocol conversion technology in a 5G system.

[0002] Digital factories and Industry 4.0 require mobile communications that are real-time and have predictable latency. Also, a function that allows networks and devices with different profiles to coexist using the PnP method is desirable. PnP stands for Plug and Play. Therefore, time sharing is necessary. 3GPP (registered trademark) aims to expand the application of 5G systems from mobile broadband services to industrial networks. 3GPP stands for 3rd Generation Partnership Project. 5G stands for 5 Generation. Local 5G URLLC enables seamless communication for mobile devices on industrial networks. URLLC stands for Ultra-Reliable and Low Latency Communications. Therefore, there is growing interest in time synchronization between devices of different profiles connected to 5G systems.

[0003] When wired networks or terminals with different time synchronization profiles are mixed, it is necessary to add a function for interpreting time synchronization messages. Patent Document 1 describes a technology for converting the format of data to be transmitted depending on the type of network at the port of a relay device. Patent Document 2 describes a technology for generating frames related to time synchronization using profile technology. It is conceivable to combine the technologies described in Patent Documents 1 and 2 and configure the relay device to convert into time synchronization messages with different time synchronization profiles. This makes it possible to realize a function for interpreting time synchronization messages in the relay device.

[0004] JP 2017-212728 A JP 2016-184809 A

[0005] Terminals with different time synchronization profiles may be connected through a 5G system. In this case, the 5G system must function as the relay device described above and implement the time synchronization message interpretation function. However, the 5G system is a system composed of multiple devices, and no device has the information necessary to implement the time synchronization message interpretation function. The present disclosure aims to enable the implementation of the time synchronization message interpretation function in a 5G system.

[0006] The DS-TT device according to the present disclosure is a DS-TT (Device-Side Time-sensitive networking Translator) device in a 5GS (5 Generation System), and is a PDU (Packet Data Unit) session established between a UE (User Equipment) and a UPF (User Plane Function) device, and is capable of storing information on both an IP (Internet Protocol) PDU and an Ethernet PDU. The DS-TT device includes: a protocol conversion unit that converts the contents of a message body of a PTP (Precision Time Protocol) message received via the PDU session, and the data type of the PTP message received according to a combination of the data type of the PTP message destination.

[0007] In the present disclosure, the DS-TT device identifies the data type of a PTP message received from the 5G system side using the data type of the PTP message received via a PDU session established between the UE and the UPF device, which can store information on both IP PDUs and Ethernet PDUs. This enables the DS-TT device to realize a time synchronization message interpretation function.

[0008] 1 is a configuration diagram of a 5G system 100 according to the first embodiment. A configuration diagram of a UE 40 according to the first embodiment. A configuration diagram of a DS-TT device 50 according to the first embodiment. An explanatory diagram of an overview of the operation of the 5G system 100 according to the first embodiment. A flowchart showing the overall operation of the DS-TT device 50 according to the first embodiment. A flowchart of type determination processing according to the first embodiment. An explanatory diagram of a data type combination according to the first embodiment. A flowchart of protocol conversion processing according to the first embodiment. An explanatory diagram of conversion between an IEEE 1588-2019 one-step sync message and an IEEE 802.1AS one-step sync message according to the first embodiment. An explanatory diagram of conversion between an IEEE 1588-2019 two-step sync message and an IEEE 802.1AS two-step sync message according to the first embodiment. 1 is an explanatory diagram of conversion between a one-step Sync message of IEEE 1588-2019 and a two-step Sync message of IEEE 802.1AS according to the first embodiment. FIG. 2 is an explanatory diagram of conversion between a two-step Sync message of IEEE 1588-2019 and a one-step Sync message of IEEE 802.1AS according to the first embodiment. FIG. 3 is an explanatory diagram of conversion of an Announce message according to the first embodiment. FIG. 4 is an explanatory diagram of conversion of a Pdelay_Req message according to the first embodiment. FIG. 5 is an explanatory diagram of processing for a Delay_Req message according to the first embodiment. FIG. 6 is a flowchart of transmission information conversion processing according to the first embodiment. FIG. 7 is an explanatory diagram of conversion processing for combination (A) according to the first embodiment. FIG. 8 is an explanatory diagram of conversion processing for combination (B) according to the first embodiment. FIG. 9 is an explanatory diagram of conversion processing for combination (C) according to the first embodiment. FIG. 10 is an explanatory diagram of conversion processing for combination (D) according to the first embodiment.

[0009] Embodiment 1. *** Description of Configuration *** The configuration of a 5G system 100 according to embodiment 1 will be described with reference to Figure 1. The 5G system 100 includes a TSCTSF device 10, a UPF device 20, an NW-TT device 30, and a plurality of sets of UEs 40 and DS-TT devices 50. Here, the NW-TT device 30 is mounted on the UPF device 20, but is not limited to this. TSCTSF is an abbreviation for Time Sensitive Communication Time Synchronization Function. UPF is an abbreviation for User Plane Function. NW-TT is an abbreviation for Network-side Time-sensitive networking Translator. UE is an abbreviation for User Equipment. DS-TT is an abbreviation for Device-Side Time-sensitive networking Translator. A PDU session 60 is established between the UE 40 and the UPF device 20 in each pair of a UE 40 and a DS-TT device 50. PDU is an abbreviation for Packet Data Unit.

[0010] A terminal connected to the network side and a terminal connected to the device side communicate via a 5G system. A message transmitted from a terminal connected to the network side is input to the NW-TT device 30. This message is transmitted to the DS-TT device 50 via a PDU session 60 established between the UE 40 and the UPF device 20 in a pair including the DS-TT device 50 to which the destination device is connected. Then, this message is transmitted from the DS-TT device 50 to a terminal connected to the device side. A message transmitted from a terminal connected to the device side is input to the DS-TT device 50. This message is transmitted to the NW-TT device 30 via a PDU session 60 established between the UE 40 and the UPF device 20 in a pair including the DS-TT device 50. Then, this message is transmitted from the NW-TT device 30 to a terminal connected to the network side.

[0011] In the first embodiment, the DS-TT device 50 realizes the translation function of the time synchronization message.

[0012] The configuration of UE 40 according to the first embodiment will be described with reference to Fig. 2. UE 40 is a computer. UE 40 includes hardware such as a processor 41, a memory 42, a storage 43, and a communication interface 44. Processor 41 is connected to other hardware via signal lines and controls the other hardware.

[0013] The UE 40 includes a session establishment unit 411 as a functional component. The functions of the functional components of the UE 40 are realized by software. A program that realizes the functions of the functional components of the UE 40 is stored in the storage 43. This program is loaded into the memory 42 by the processor 41 and executed by the processor 41. In this way, the functions of the functional components of the UE 40 are realized.

[0014] The configuration of a DS-TT device 50 according to the first embodiment will be described with reference to Figure 3. The DS-TT device 50 is a computer. The DS-TT device 50 comprises the following hardware: a processor 51, a memory 52, a storage 53, a first communication interface 54, and a second communication interface 55. The processor 51 is connected to other hardware via signal lines and controls this other hardware.

[0015] The DS-TT device 50 comprises, as functional components, a time synchronization unit 511, an information acquisition unit 512, a type determination unit 513, and a conversion unit 514. The conversion unit 514 comprises a protocol conversion unit 515 and a transmission processing unit 516. The functions of each functional component of the DS-TT device 50 are realized by software. The storage 53 stores a program that realizes the function of each functional component of the DS-TT device 50. This program is read into the memory 52 by the processor 51 and executed by the processor 51. In this way, the function of each functional component of the DS-TT device 50 is realized.

[0016] The processors 41 and 51 are ICs that perform processing. IC stands for Integrated Circuit. Specific examples of the processors 41 and 51 are a CPU, a DSP, and a GPU. CPU stands for Central Processing Unit. DSP stands for Digital Signal Processor. GPU stands for Graphics Processing Unit.

[0017] The memories 42 and 52 are storage devices that temporarily store data. Specific examples of the memories 42 and 52 are SRAM and DRAM. SRAM stands for Static Random Access Memory. DRAM stands for Dynamic Random Access Memory.

[0018] The storages 43 and 53 are storage devices that store data. Specific examples of the storages 43 and 53 are HDDs. HDD stands for Hard Disk Drive. The storages 43 and 53 may also be portable recording media such as an SD (registered trademark) memory card, CompactFlash (registered trademark), NAND flash, a flexible disk, an optical disk, a compact disk, a Blu-ray (registered trademark) disk, or a DVD. SD stands for Secure Digital. DVD stands for Digital Versatile Disk.

[0019] The communication interface 44 is an interface for communicating with the NW-TT device 30. The first communication interface 54 is an interface for communicating with a device connected to the network side. The second communication interface 55 is an interface for communicating with a device connected to the 5G system 100 side. In other words, the second communication interface 55 is an interface for communicating via a PDU session 60. The communication interface 44, the first communication interface 54, and the second communication interface 55 are, as specific examples, ports for communication.

[0020] ***Description of Operation*** The operation of the 5G system 100 according to the first embodiment will be described with reference to Figures 4 to 20. The operation procedure of the 5G system 100 according to the first embodiment corresponds to the message conversion method according to the first embodiment. Furthermore, the program that realizes the operation of the 5G system 100 according to the first embodiment corresponds to the message conversion program according to the first embodiment.

[0021] In the first embodiment, it is assumed that the time synchronization message is a PTP message. PTP is an abbreviation for Precision Time Protocol. In the first embodiment, it is assumed that there are three types of data types for PTP messages: IP packets of IEEE 1588-2019, Ethernet frames of IEEE 1588-2019, and Ethernet frames of IEEE 802.1AS. In the following description, IP packets of IEEE 1588-2019 are referred to as IP1588. Ethernet frames of 1588-2019 are referred to as Ethernet1588. Ethernet frames of IEEE 802.1AS are referred to as Ethernet1AS.

[0022] An overview of the operation of the 5G system 100 according to the first embodiment will be described with reference to FIG. 4. There are two cases for protocol conversion: (1) and (2). (1) The DS-TT device 50 receives a PTP message from the device side, performs protocol conversion, and transmits it to the 5G system 100 side. (2) The DS-TT device 50 receives a PTP message from the 5G system 100 side, performs protocol conversion, and transmits it to the device side. Protocol conversion requires the data type of the sender and the data type of the destination. The data type of the sender is the data type of the transmitted PTP message. In case (1), the DS-TT device 50 can identify the data types of the sender and the destination. In case (2), the DS-TT device 50 can identify the data type of the destination. However, there is a possibility that data may be missing from the transmitted PTP message, and the DS-TT device 50 may not be able to identify the data type of the 5G system 100 side that is the sender. This is because the PDU session 60 established between the UE 40 and the UPF device 20 is either an IP PDU session or an Ethernet PDU session. The PDU session 60 is either an IP PDU session or an Ethernet PDU session depending on the terminal connected to the device side. Therefore, in the first embodiment, the UE 40 establishes a PDU session 60 including the MAC address of the DS-TT device and the IP address information of the UE with the UPF device 20. This prevents data from being lost in the PTP message received by the DS-TT device 50.

[0023] The UE 40 is a device that establishes a PDU session 60 with the UPF device 20. The session establishment unit 411 of the UE 40 transmits a request to the UPF device 20 to establish an Unstructured PDU session. At this time, the session establishment unit 411 uses a configuration including both the MAC address of the DS-TT device and the IP address information of the UE 40 as the format of the Unstructured PDU session. As a result, the Unstructured PDU session is established as the PDU session 60. The DS-TT device 50 receives a PTP message from the 5G system 100 side. If the data type of the sender of the received PTP message is IP, information is set in the IP field. If the data type of the sender of the received PTP message is Ethernet, information is set in the Ethernet field. Therefore, the DS-TT device 50 can receive the PTP message data without any loss. This allows the DS-TT device 50 to perform protocol conversion even in case (2). The DS-TT device 50 converts the PTP message according to the combination of the data type of the sender and the data type of the destination. The NW-TT device 30 then transmits the converted PTP message to the destination.

[0024] The overall operation of the DS-TT device 50 according to the first embodiment will be described with reference to Fig. 5. (Step S1: Time Synchronization Processing) Upon receiving a PTP message, the time synchronization unit 511 executes processing related to time synchronization based on the PTP message.

[0025] (Step S2: Type Determination Process) The type determination unit 513 identifies a combination of the data type of the transmission source and the data type of the transmission destination. At this time, when a PTP message is received from the 5G system 100, the information acquisition unit 512 acquires data from the IP session or the Ethernet session in the PDU session 60. Then, the type determination unit 513 identifies the data type based on the data acquired by the information acquisition unit 512, and identifies the combination.

[0026] If the data type of the sender and the data type of the destination are the same, the type determination unit 513 skips the processes of steps S3 and S4 and proceeds to step S5. On the other hand, if the data type of the sender and the data type of the destination are different, the type determination unit 513 proceeds to step S3. In steps S3 and S4, the conversion unit 514 converts the PTP message in accordance with the combination identified in step S2.

[0027] (Step S3: Protocol conversion process) The protocol conversion unit 515 converts the content of the message body of the PTP message according to the combination identified in step S2. Specifically, the protocol conversion unit 515 converts the content of the message body of the PTP message to content that matches the data type of the PDU session 60 for the destination of the PTP message.

[0028] (Step S4: Transmission information conversion process) The transmission processing unit 516 converts the configuration of the transmission information indicating the destination and source of the PTP message. Specifically, the transmission processing unit 516 converts the configuration of the transmission information of the PTP message into content that matches the data type of the PDU session 60 for the destination of the PTP message.

[0029] (Step S5: Transmission Process) The transmission processing unit 516 transmits the PTP message to the destination.

[0030] The operation of the type determination process (step S2 in FIG. 5) according to the first embodiment will be described with reference to FIG. 6. When a PTP message is received from the device side, even an existing DS-TT device can identify the combination of the data type of the sender and the data type of the destination. Therefore, here, a case where a PTP message is received from the 5G system 100 side will be described.

[0031] (Step S21: IP field determination process) The type determination unit 513 determines whether the IP field of the PDU session 60 is empty. If the type determination unit 513 determines that the IP field is not empty, the process proceeds to step S22. On the other hand, if the type determination unit 513 determines that the IP field is empty, the process proceeds to step S23.

[0032] (Step S22: First information extraction process) The type determination unit 513 extracts information from the IP field of the PDU session 60. Then, the type determination unit 513 identifies the data type of the sender from the configuration of the extracted information.

[0033] (Step S23: Ethernet field determination process) The type determination unit 513 determines whether the Ethernet field of the PDU session 60 is empty. If the type determination unit 513 determines that the field is not empty, the process proceeds to step S24. On the other hand, if the field is empty, the type determination unit 513 determines that an error has occurred and terminates the process.

[0034] (Step S24: Second information extraction process) The type determination unit 513 extracts information from the Ethernet field of the PDU session 60. Then, the type determination unit 513 identifies the data type of the transmission source from the configuration of the extracted information.

[0035] (Step S25: Device-side identification process) The type determination unit 513 identifies the data type on the device side that is the destination. On the device side, the DS-TT device 50 has data type information and can identify the data type.

[0036] (Step S26: Combination Identification Process) The type determination unit 513 identifies the combination of the data type of the sender identified in step S22 or step S24 and the data type of the destination identified in step S25. If the data type of the sender and the data type of the destination are the same, the type determination unit 513 proceeds to step S5 in Fig. 5. On the other hand, if the data type of the sender and the data type of the destination are different, the type determination unit 513 proceeds to step S3 in Fig. 5.

[0037] There are six cases where the data type of the sender and the data type of the destination are different, as shown in Figure 7, (A) to (F). (A) The sender is IP1588 and the destination is Ethernet1588. (B) The sender is Ethernet1588 and the destination is IP1588. (C) The sender is Ethernet1588 and the destination is Ethernet1AS. (D) The sender is Ethernet1AS and the destination is Ethernet1588. (E) The sender is IP1588 and the destination is Ethernet1AS. (F) The sender is Ethernet1AS and the destination is IP1588.

[0038] The protocol conversion process (step S3 in FIG. 5) according to the first embodiment will be described with reference to FIG. 8. (Step S31: Conversion Determination Process) The protocol conversion unit 515 determines whether the combination identified in step S2 is a combination that requires message body conversion. If the combination requires message body conversion, the protocol conversion unit 515 proceeds to step S32. On the other hand, if the combination does not require message body conversion, the protocol conversion unit 515 outputs the message body of the received PTP message as is.

[0039] In the first embodiment, of the six types (A) to (F), the combinations (A) and (B) in which both the source and destination use the IEEE 1588-2019 protocol are combinations in which message body conversion is not required. The other combinations (C) to (F) are combinations in which the source and destination use different protocols and require message body conversion.

[0040] (Step S32: Message Type Determination Process) The protocol conversion unit 515 determines the message type of the PTP message. In the first embodiment, the message types of the PTP message include a Sync message, a Follow_Up message, an Announce message, a Pdelay_Req message, a Pdelay_Resp message, and a DelayReq message.

[0041] First, the protocol conversion unit 515 determines whether the message type of the sender or destination is a Sync message or a Follow_Up message. If the message type is a Sync message or a Follow_Up message, the protocol conversion unit 515 proceeds to step S33. If the message type is neither a Sync message nor a Follow_Up message, the protocol conversion unit 515 determines whether the message type is an Announce message. If the message type is an Announce message, the protocol conversion unit 515 proceeds to step S34. If the message type is not an Announce message, the protocol conversion unit 515 determines whether the message type is either a Pdelay_Req message or a Pdelay_Resp message. If the message type is either a Pdelay_Req message or a Pdelay_Resp, the protocol conversion unit 515 proceeds to step S35. If the message type is neither a Pdelay_Req message nor a Pdelay_Resp, the protocol conversion unit 515 determines whether the message type is a DelayReq message. If the message type is a DelayReq message, the protocol conversion unit 515 proceeds to step S36. If the message type is not a DelayReq message, the protocol conversion unit 515 terminates the process as an error.

[0042] (Step S33: First Conversion Process) The protocol conversion unit 515 processes the Sync message and the Follow_Up message together. Here, there are one-step synchronization and two-step synchronization in the synchronization process. In one-step synchronization, synchronization is performed using only the Sync message. In contrast, in two-step synchronization, synchronization is performed using the Sync message and the Follow_Up message. There are four patterns of conversion here, (a) to (d). (a) Conversion between the one-step Sync message of IEEE 1588-2019 and the one-step Sync message of IEEE 802.1AS. (b) Conversion between the two-step Sync message of IEEE 1588-2019 and the two-step Sync message of IEEE 802.1AS. (c) Conversion between IEEE 1588-2019 one-step Sync messages and IEEE 802.1AS two-step Sync messages. (d) Conversion between IEEE 1588-2019 two-step Sync messages and IEEE 802.1AS one-step Sync messages.

[0043] Referring to FIG. 9, (a) conversion between an IEEE 1588-2019 one-step sync message and an IEEE 802.1AS one-step sync message will be described. When the source message type is an IEEE 1588-2019 sync message, the protocol conversion unit 515 adds a Follow_Up information TLV. TLV stands for Type Length Value. Here, the protocol conversion unit 515 assumes that the clock deviation between the NW-TT device 30 and the time synchronization master device is 0. Then, as shown in FIG. 9, the protocol conversion unit 515 adds a Follow_Up information TLV. On the other hand, if the message type of the sender is a Sync message in IEEE802.1AS, the protocol conversion unit 515 changes the frame length and deletes the Follow_Up information TLV.

[0044] 10, (b) the conversion between the IEEE 1588-2019 two-step Sync message and the IEEE 802.1AS two-step Sync message will be described. If the source message type is an IEEE 1588-2019 Sync message, the protocol conversion unit 515 adds a Follow_Up information TLV to the Follow_Up message. Also, if the source message type is an IEEE 1588-2019 Sync message, the protocol conversion unit 515 sets all of the fields containing "originTimestamp" to 0. On the other hand, if the message type of the sender is a Sync message in IEEE802.1AS, the protocol conversion unit 515 changes the frame length and deletes the Follow_Up information TLV in the Follow_Up message.

[0045] Referring to Figure 11, (c) the conversion between the 1-step Sync message of IEEE1588-2019 and the 2-step Sync message of IEEE802.1AS will be described. When the message type of the sender is a Sync message in IEEE1588-2019, the protocol conversion unit 515 generates a Follow_Up message in IEEE802.1AS. At this time, the protocol conversion unit 515 sets the value of the originTimestamp field of the Sync message to the PreciseOriginTimestamp field of the Follow_Up message. In addition, the protocol conversion unit 515 sets the Follow_Up information TLV. Furthermore, if the message type of the sender is a Sync message in IEEE 1588-2019, the protocol conversion unit 515 sets all of the fields in the originTimestamp to 0. On the other hand, if the message type of the sender is a Sync message in IEEE 802.1AS, the protocol conversion unit 515 sets the value of the PreciseoriginTimestamp field of the Follow_Up message in IEEE 802.1AS to the reserved field of the Sync message.

[0046] 12, (d) the conversion between the IEEE 1588-2019 two-step Sync message and the IEEE 802.1AS one-step Sync message will be described. When the source message type is an IEEE 1588-2019 Sync message, the protocol conversion unit 515 adds a Follow_Up information TLV. In addition, the protocol conversion unit 515 sets the value of the Precise origin timestamp field of the Follow_Up message to the origin timestamp field of the IEEE 802.1AS Sync message. On the other hand, if the message type of the sender is a Sync message in IEEE 802.1AS, the protocol conversion unit 515 generates a Follow_Up message in IEEE 1588-2019. At this time, the protocol conversion unit 515 sets the value of the originTimestamp field of the Sync message to the PreciseOriginTimestamp field of the Follow_Up message. In addition, the protocol conversion unit 515 sets all of the originTimestamp fields of the Sync message to 0.

[0047] (Step S34: Second Conversion Process) The protocol conversion unit 515 adds or deletes a TLV field to or from the Announce message.

[0048] The case of an Announce message will be specifically described with reference to Fig. 13. If the message type of the sender is an Announce message in IEEE1588-2019, the protocol conversion unit 515 adds a PATH TRACE TLV. Furthermore, the protocol conversion unit 515 sets all fields containing originTimestamp to 0. On the other hand, if the message type of the sender is an Announce message in IEEE802.1AS, the protocol conversion unit 515 changes the frame length and deletes the PATH TRACE TLV.

[0049] Here, the protocol conversion unit 515 configures PATH TRACE TLV information from the MAC address of the time-synchronized master device in the Announce message, the MAC address of the NW-TT device 30, and the stepRemoved information in the Announce message. Because the MAC addresses of the devices between the master device and the NW-TT device 30 are unknown, the protocol conversion unit 515 sets them to specific values ​​(for example, all 0s). As a specific example, the PATH TRACE TLV information is configured as shown in FIG. 13. Here, the stepRemoved information in the Announce message is set to N.

[0050] (Step S35: Third Conversion Process) The protocol conversion unit 315 converts the items of the Pdelay_Req message.

[0051] This will be described in detail with reference to Fig. 14. When the message type of the sender is a Pdelay_Req message in IEEE1588-2019, the protocol conversion unit 315 sets all fields corresponding to originTimestamp to 0. Note that no conversion is required for a Pdelay_Resp message.

[0052] (Step S36: Fourth Conversion Process) The protocol conversion unit 515 transmits a Delay_Resp message to the sender.

[0053] A specific description will be given with reference to FIG. 15. IEEE 1588-2019 includes a Delay_Req message and a Delay_Resp message. However, these messages do not exist in IEEE 802.1AS. Therefore, when a Delay_Req message is received, the protocol conversion unit 515 does not send a Delay_Req message to the destination, but sends a Delay_Resp message to the source. At this time, the protocol conversion unit 515 sets the difference in the delay value between the 5G system and the grandmaster calculated by the 5G system from the timestamp value acquired by the 5G system 100 in the receiveTimestamp field of the Delay_Resp message.

[0054] Note that the protocol conversion between IEEE 1588-2019 and IEEE 802.1AS has been described here. However, protocol conversion between other protocols is also possible according to the above-described concepts. The above-described concepts are the four concepts (S) to (V). (S) The protocol conversion unit 515 converts a message with TLVs into a message without TLVs. In this case, the protocol conversion unit 515 deletes the TLVs. (T) The protocol conversion unit 515 converts a message without TLVs into a message with TLVs. In this case, the protocol conversion unit 515 sets TLVs such as the Follow_Up information TLV described in step S33 and the PATH TRACE TLV described in step S34. (U) The protocol conversion unit 515 switches the timestamp between one-step synchronization messages and two-step synchronization messages. Specifically, the protocol conversion unit 515 uses the originTimestamp of the Sync message in the case of one-step synchronization, and uses the PreciseoriginTimestamp of the Follow_Up message in the case of two-step synchronization. (V) When a message that does not exist in the destination's data type and that requests a reply is received, a reply message is sent to the destination. Specifically, when a Delay_Req message and a Delay_Resp message do not exist in the destination's data type, and a Delay_Req message is received, a Delay_Resp message is sent to the sender.

[0055] The transmission information conversion process (step S4 in FIG. 5) according to the first embodiment will be described with reference to FIG. 16. (Step S41: Combination Determination Process) The transmission processing unit 516 determines which combination in FIG. 7 the combination identified in step S2 corresponds to. If the combination is (A), the transmission processing unit 516 proceeds to process step S42. If the combination is (B), the transmission processing unit 516 proceeds to process step S43. If the combination is (C), the transmission processing unit 516 proceeds to process step S44. If the combination is (D), the transmission processing unit 516 proceeds to process step S45. If the combination is (E), the transmission processing unit 516 proceeds to process step S46. If the combination is (F), the transmission processing unit 516 proceeds to process step S47.

[0056] (Step S42: A Conversion Process) As shown in FIG. 17, the transmission processing unit 516 converts the IP header and UDP header into a DA, SA, and EtherType. DA stands for Destination MAC Address. SA stands for Source MAC Address. MAC stands for Media Access Control. Specifically, the transmission processing unit 516 prepares in advance a DA, SA, and EtherType in which the information shown in FIG. 17 is set. Then, the transmission processing unit 516 replaces the IP header and UDP header with the prepared DA, SA, and EtherType.

[0057] (Step S43: Conversion Process B) The transmission processing unit 516 converts the DA, SA, and EtherType into an IP header and a UDP header, as shown in Fig. 18. Specifically, the transmission processing unit 516 prepares in advance the IP header and the UDP header shown in Fig. 18. Then, the transmission processing unit 516 replaces the DA, SA, and EtherType with the prepared IP header and the UDP header.

[0058] (Step S44: C Conversion Process) As shown in FIG. 19, the transmission processing unit 516 replaces the DA for Ethernet1588 with the DA for Ethernet1AS.

[0059] (Step S45: D Conversion Process) The transmission processing unit 516 replaces the DA for Ethernet1AS with a DA for Ethernet1588, as shown in FIG.

[0060] (Step S46: E Conversion Process) The E conversion process can be realized by combining the A conversion process and the C conversion process. Therefore, the transmission processing unit 516 performs the process of step S42 and then the process of step S44. That is, after converting IP1588 to Ethernet1588, it converts Ethernet1588 to Ethernet1AS.

[0061] (Step S47: F Conversion Process) The F conversion process can be realized by combining the D conversion process and the B conversion process. Therefore, the transmission processing unit 516 performs the process of step S45 and then the process of step S43. That is, after converting Ethernet1AS to Ethernet1588, it converts Ethernet1588 to IP1588.

[0062] ***Effects of First Embodiment*** As described above, in the 5G system 100 according to the first embodiment, the UE 40 establishes a PDU session 60 capable of storing information on both IP PDUs and Ethernet PDUs with the UPF device 20. Then, the DS-TT device 50 identifies the data type of the PTP message received from the 5G system 100 side using the data type of the PTP message received via the PDU session 60. This allows the DS-TT device 50 to identify the data type of the PTP message received from the 5G system 100 side. As a result, the DS-TT device 50 can realize the interpretation function of the time synchronization message.

[0063] The DS-TT device 50 according to the first embodiment converts the contents of the message body of a PTP message to match the data type of the destination, using a method that corresponds to the combination of the data type of the source and the data type of the destination. This makes it possible to realize protocol conversion of time synchronization messages.

[0064] The DS-TT device 50 according to the first embodiment converts the structure of the transmission information of the PTP message to match the data type of the destination by a method according to the combination of the data type of the source and the data type of the destination, thereby enabling the conversion of the transmission information of the time synchronization message.

[0065] In the 5G system 100 according to the first embodiment, when the DS-TT device 50 receives a Delay_Req message in IEEE1588-2019 when the destination protocol is IEEE802.1AS, it transmits a Delay_Resp message to the sender. This makes it possible to appropriately respond to the Delay_Req message received from the sender.

[0066] ***Other Configurations*** <Modification 1> In the first embodiment, each functional component is realized by software. However, in Modification 1, each functional component may be realized by hardware. The differences between Modification 1 and the first embodiment will be described below.

[0067] When each functional component is realized by hardware, the UE 40 includes an electronic circuit instead of the processor 41, the memory 42, and the storage 43. The electronic circuit is a dedicated circuit that realizes the functions of each functional component, the memory 42, and the storage 43.

[0068] When each functional component is realized by hardware, the DS-TT device 50 includes an electronic circuit in place of the processor 51, memory 52, and storage 53. The electronic circuit is a dedicated circuit that realizes the functions of each functional component, memory 52, and storage 53.

[0069] Possible electronic circuits include a single circuit, a composite circuit, a programmed processor, a parallel programmed processor, a logic IC, a GA, an ASIC, and an FPGA. GA stands for Gate Array. ASIC stands for Application Specific Integrated Circuit. FPGA stands for Field-Programmable Gate Array. Each functional component may be realized by a single electronic circuit, or each functional component may be distributed across multiple electronic circuits.

[0070] <Modification 2> As a modification 2, some of the functional components may be realized by hardware, and other functional components may be realized by software.

[0071] The processors 41 and 51, the memories 42 and 52, the storages 43 and 53, and the electronic circuits are collectively referred to as a processing circuit. In other words, the functions of the functional components are realized by the processing circuit.

[0072] Furthermore, the term "unit" in the above description may be read as a "circuit," "step," "procedure," "process," or "processing circuit."

[0073] The embodiments and modifications of the present disclosure have been described above. Some of these embodiments and modifications may be combined and implemented. Furthermore, one or more of them may be implemented partially. Note that the present disclosure is not limited to the above embodiments and modifications, and various modifications are possible as needed.

[0074] 100 5G system, 10 TSCTSF device, 20 UPF device, 30 NW-TT device, 40 UE, 41 processor, 42 memory, 43 storage, 44 communication interface, 411 session establishment unit, 50 DS-TT device, 51 processor, 52 memory, 53 storage, 54 first communication interface, 55 second communication interface, 511 time synchronization unit, 512 information acquisition unit, 513 type determination unit, 514 conversion unit, 515 protocol conversion unit, 516 transmission processing unit, 60 PDU session.

Claims

1. A DS-TT (Device-Side Time-sensitive networking Translator) device in 5GS (5 Generation System), a protocol conversion unit that converts the contents of a message body of a Precision Time Protocol (PTP) message according to a combination of a data type of the PTP message received through a Packet Data Unit (PDU) session established between a User Equipment (UE) and a User Plane Function (UPF) device, the PDU session being capable of storing information of both an Internet Protocol (IP) PDU and an Ethernet PDU, and a data type of a destination of the PTP message; A DS-TT device comprising:

2. The protocol conversion unit converts the content of the message body of the PTP message into content that matches the data type of the destination. The DS-TT device according to claim 1.

3. The protocol conversion unit converts the content of the message body according to the message type of the PTP message. The DS-TT device according to claim 1.

4. The protocol conversion unit transmits a reply message to the destination when the protocol conversion unit receives a message that does not exist in the data type of the destination and that requests a reply. The DS-TT device according to claim 2.

5. The DS-TT device further comprises: a transmission processing unit that converts a configuration of transmission information indicating a destination and a source of the PTP message according to the combination and transmits the converted information to the destination. The DS-TT device of claim 1 .

6. A 5G (5 Generation) system including a UE (User Equipment) and a DS-TT (Device-Side Time-sensitive networking Translator) device, The UE establishes a PDU session capable of storing both information of an IP (Internet Protocol) PDU (Packet Data Unit) and an Ethernet PDU with a UPF (User Plane Function) device; The DS-TT device converts the contents of the message body of the Precision Time Protocol (PTP) message according to a combination of the data type of the PTP message received via the PDU session and the data type of the destination of the PTP message. 5G system.

7. A UE (User Equipment) in 5GS (5 Generation System), A session establishment unit that establishes a PDU session for transmitting a Precision Time Protocol (PTP) message to a Device-Side Time-sensitive networking Translator (DS-TT) device that converts the contents of a message body of a PTP message, the PDU session being capable of storing both information of an Internet Protocol (IP) PDU (Packet Data Unit) and an Ethernet PDU between a User Plane Function (UPF) device and the DS-TT device. A UE comprising:

8. A message conversion method in a 5G (5 Generation) system, A UE (User Equipment) establishes a PDU session capable of storing both IP (Internet Protocol) PDU (Packet Data Unit) and Ethernet PDU information with a UPF (User Plane Function) device; A message conversion method in which a DS-TT (Device-Side Time-sensitive networking Translator) device converts the contents of a message body of a Precision Time Protocol (PTP) message according to a combination of a data type of the PTP message received via the PDU session and a data type of a destination of the PTP message.