JP7710629B2 - DS-TT device, 5G system, UE, and message conversion method - Google Patents

Description

This disclosure relates to time synchronization protocol conversion technology in 5G systems.

Digital factories and Industry 4.0 require mobile communications that are real-time and have predictable delays. In addition, a function that allows networks with different profiles and terminals with different profiles to coexist using the PnP method is desirable. PnP stands for Plug and Play. For this reason, 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 in industrial networks. URLLC stands for Ultra-Reliable and Low Latency Communications. Therefore, interest in time synchronization between devices of different profiles connected to 5G systems is increasing.

When wired networks or terminals with different time synchronization profiles are mixed, a function for interpreting time synchronization messages must be added.
Patent Literature 1 describes a technique for converting the format of data to be transmitted depending on the type of network of a port of a relay device. Patent Literature 2 describes a technique for generating frames related to time synchronization using profile technology. It is conceivable to combine the techniques described in Patent Literature 1 and 2 and configure the relay device to convert into a time synchronization message of a different time synchronization profile. This makes it possible to realize a function of interpreting the time synchronization message in the relay device.

JP 2017-212728 A JP 2016-184809 A

There are cases where terminals having different time synchronization profiles are connected through a 5G system. In this case, the 5G system must function as the relay device described above to realize the translation function of the time synchronization message. However, the 5G system is a system composed of multiple devices, and there is no device having the information necessary to realize the translation function of the time synchronization message.
The present disclosure aims to make it possible to realize a time synchronization message interpretation function in a 5G system.

The DS-TT device according to the present disclosure comprises:
A DS-TT (Device-Side Time-sensitive networking Translator) device in 5GS (5 Generation System),
The present invention includes a protocol conversion unit that converts the contents of a message body of a Precision Time Protocol (PTP) message received via 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, in accordance with a combination of a data type of the PTP message and a data type of a destination of the PTP message.

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

FIG. 1 is a configuration diagram of a 5G system 100 according to a first embodiment. FIG. 2 is a configuration diagram of a UE 40 according to the first embodiment. FIG. 2 is a configuration diagram of a DS-TT device 50 according to the first embodiment. An explanatory diagram of an overview of the operation of a 5G system 100 relating to embodiment 1. 4 is a flowchart showing the overall operation of the DS-TT device 50 according to the first embodiment. 13 is a flowchart of a type determination process according to the first embodiment. FIG. 4 is an explanatory diagram of a combination of data types according to the first embodiment. 4 is a flowchart of a protocol conversion process according to the first embodiment. FIG. 1 is an explanatory diagram of conversion between an IEEE 1588-2019 1-step Sync message and an IEEE 802.1AS 1-step Sync message according to the first embodiment. FIG. 1 is an explanatory diagram of conversion between a two-step Sync message of IEEE 1588-2019 and a two-step Sync message of IEEE 802.1AS according to the first embodiment. FIG. 1 is an explanatory diagram of conversion between an IEEE 1588-2019 one-step Sync message and an IEEE 802.1AS two-step Sync message according to the first embodiment. FIG. 1 is an explanatory diagram of conversion between an IEEE 1588-2019 two-step Sync message and an IEEE 802.1AS one-step Sync message according to the first embodiment. FIG. 4 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. 4 is an explanatory diagram of processing for a Delay_Req message according to the first embodiment; 13 is a flowchart of a transmission information conversion process according to the first embodiment. FIG. 11 is an explanatory diagram of a conversion process in the case of combination (A) according to the first embodiment. FIG. 11 is an explanatory diagram of a conversion process in the case of combination (B) according to the first embodiment. FIG. 11 is an explanatory diagram of a conversion process in the case of combination (C) according to the first embodiment. FIG. 13 is an explanatory diagram of a conversion process in the case of combination (D) according to the first embodiment.

Embodiment 1.
***Configuration Description***
With reference to FIG. 1, the configuration of a 5G system 100 according to the first embodiment will be described.
The 5G system 100 includes a TSCTSF device 10, a UPF device 20, an NW-TT device 30, and a plurality of sets of a UE 40 and a DS-TT device 50. Here, the NW-TT device 30 is mounted on the UPF device 20, but is not limited thereto. TSCTSF stands for Time Sensitive Communication Time Synchronization Function. UPF stands for User Plane Function. NW-TT stands for Network-side Time-sensitive networking Translator. UE stands for User Equipment. DS-TT stands 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 the UE 40 and the DS-TT device 50. PDU is an abbreviation for Packet Data Unit.

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 the 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.

In embodiment 1, the DS-TT device 50 provides an interpretation function for time synchronization messages.

The configuration of the UE 40 according to the first embodiment will be described with reference to FIG.
The UE 40 is a computer.
The UE 40 includes the following hardware components: a processor 41, a memory 42, a storage 43, and a communication interface 44. The processor 41 is connected to other hardware components via signal lines and controls the other hardware components.

The UE 40 includes, as a functional component, a session establishment unit 411. The functions of the functional components of the UE 40 are realized by software.
The storage 43 stores a program that realizes the functions of the functional components of the UE 40. The 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.

The configuration of a DS-TT device 50 according to the first embodiment will be described with reference to FIG.
The DS-TT device 50 is a computer.
The DS-TT device 50 comprises the following hardware components: 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 components via signal lines and controls the other hardware components.

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 the functional components of the DS-TT device 50 are realized by software.
The storage 53 stores programs that realize the functions of each functional component of the DS-TT device 50. These programs are loaded into the memory 52 by the processor 51 and executed by the processor 51. In this way, the functions of each functional component of the DS-TT device 50 are realized.

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

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

Storage 43, 53 is a storage device that stores data. A specific example of storage 43, 53 is a HDD. HDD is an abbreviation for Hard Disk Drive. Storage 43, 53 may also be a portable recording medium 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 is an abbreviation for Secure Digital. DVD is an abbreviation for Digital Versatile Disk.

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 equipment connected to the network side. The second communication interface 55 is an interface for communicating with equipment connected to the 5G system 100 side. In other words, the second communication interface 55 is an interface for communicating via the PDU session 60. As specific examples, the communication interface 44, the first communication interface 54, and the second communication interface 55 are ports for communication.

*** Operation Description ***
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. Moreover, the program for realizing the operation of the 5G system 100 according to the first embodiment corresponds to the message conversion program according to the first embodiment.

In the first embodiment, the time synchronization message is a PTP message. PTP is an abbreviation for Precision Time Protocol. In the first embodiment, there are three types of data types for PTP messages: IP packets IEEE1588-2019, Ethernet frames IEEE1588-2019, and Ethernet frames IEEE802.1AS. In the following description, IP packets IEEE1588-2019 are referred to as IP1588. Ethernet frames 1588-2019 are referred to as Ethernet1588. Ethernet frames IEEE802.1AS are referred to as Ethernet1AS.

Referring to FIG. 4, an overview of the operation of the 5G system 100 according to the first embodiment will be described.
There are two cases for protocol conversion: (1) and (2) below. (1) The DS-TT device 50 receives a PTP message from the device side, converts the protocol, 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, converts the protocol, and transmits it to the device side.
To convert the protocol, the data type of the sender and the data type of the destination are required. The data type of the sender is the data type of the transmitted PTP message. In the case of (1), the DS-TT device 50 can identify the data types of the sender and the destination. In the case of (2), the DS-TT device 50 can identify the data type of the destination. However, there is a possibility that data of the transmitted PTP message may be missing, and the DS-TT device 50 may not be able to identify the data type of the sender 5G system 100. 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.

UE 40 is a device that establishes a PDU session 60 between UPF device 20. Session establishment unit 411 of UE 40 transmits a request for establishing an Unstructured PDU session to UPF device 20. At this time, session establishment unit 411 uses a configuration including both the MAC address of the DS-TT device and the IP address information of UE 40 as a format of the Unstructured PDU session. As a result, the Unstructured PDU session is established as PDU session 60.
The DS-TT device 50 receives a PTP message from the 5G system 100. 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 loss. This allows the DS-TT device 50 to perform protocol conversion even in the case of (2).
The DS-TT device 50 converts the PTP message according to the combination of the data type of the transmission source and the data type of the transmission destination. Then, the NW-TT device 30 transmits the converted PTP message to the transmission destination.

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

(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 a data type based on the data acquired by the information acquisition unit 512, and identifies a combination.

If the data type of the transmission source and the data type of the transmission 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 transmission source and the data type of the transmission 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.

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

(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.

(Step S5: Transmission process)
The transmission processing unit 516 transmits the PTP message to the destination.

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

(Step S21: IP field determination process)
The type determination unit 513 determines whether or not 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.

(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 transmission source from the configuration of the extracted information.

(Step S23: Ethernet field determination process)
The type determination unit 513 determines whether or not 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 type determination unit 513 determines that the field is empty, the process ends as an error.

(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.

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

(Step S26: Combination Identification Processing)
The type determination unit 513 determines a combination of the data type of the transmission source determined in step S22 or S24 and the data type of the transmission destination determined in step S25. If the data type of the transmission source and the data type of the transmission destination are the same, the type determination unit 513 advances the process to step S5 in Fig. 5. On the other hand, if the data type of the transmission source and the data type of the transmission destination are different, the type determination unit 513 advances the process to step S3 in Fig. 5.

There are six cases where the data type of the sender and the data type of the destination are different, (A) to (F) as shown in Figure 7. (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.

The protocol conversion process (step S3 in FIG. 5) according to the first embodiment will be described with reference to FIG.
(Step S31: Conversion determination process)
The protocol conversion unit 515 determines whether or not 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 advances the process 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.

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

(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.

First, the protocol conversion unit 515 determines whether the message type of the source 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 advances the process 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 Announcement message. If the message type is an Announcement message, the protocol conversion unit 515 advances the process to step S34.
If the received message is not an Announce message, the protocol conversion unit 515 determines whether the message type is a Pdelay_Req message or a Pdelay_Resp message. If the message type is a Pdelay_Req message or a Pdelay_Resp message, the protocol conversion unit 515 advances the process to step S35.
If the message type is neither a Pdelay_Req message nor a Pdelay_Resp message, 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 advances the process to step S36.
If the received message is not a DelayReq message, the protocol conversion unit 515 determines that an error has occurred and ends the process.

(Step S33: First conversion process)
The protocol conversion unit 515 processes the Sync message and the Follow_Up message together. There are two types of synchronization: one-step synchronization and two-step synchronization. In one-step synchronization, synchronization is performed only with the Sync message. In two-step synchronization, synchronization is performed with the Sync message and the Follow_Up message.
There are four patterns of conversion here, from (a) to (d). (a) Conversion between IEEE1588-2019 1-step Sync message and IEEE802.1AS 1-step Sync message. (b) Conversion between IEEE1588-2019 2-step Sync message and IEEE802.1AS 2-step Sync message. (c) Conversion between IEEE1588-2019 1-step Sync message and IEEE802.1AS 2-step Sync message. (d) Conversion between IEEE1588-2019 2-step Sync message and IEEE802.1AS 1-step Sync message.

With reference to FIG. 9, (a) conversion between IEEE 1588-2019 1-step Sync messages and IEEE 802.1AS 1-step Sync messages will be described.
If the message type of the sender is a Sync message in IEEE1588-2019, the protocol conversion unit 515 adds the 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-synchronized master device is 0. Then, as shown in FIG. 9, the protocol conversion unit 515 adds the 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.

With reference to FIG. 10, (b) conversion between the IEEE 1588-2019 two-step Sync message and the IEEE 802.1AS two-step Sync message will be described.
If the message type of the sender is a Sync message in IEEE1588-2019, the protocol conversion unit 515 adds a Follow_Up information TLV to the Follow_Up message. Also, if the message type of the sender is a Sync message in IEEE1588-2019, the protocol conversion unit 515 sets all of the fields in 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.

With reference to FIG. 11, (c) conversion between the 1-step Sync message of IEEE 1588-2019 and the 2-step Sync message of IEEE 802.1AS 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. In addition, when the message type of the sender is a Sync message in IEEE1588-2019, the protocol conversion unit 515 sets all of the fields that are set to originTimestamp to 0.
On the other hand, when the message type of the sender is a Sync message in IEEE802.1AS, the protocol conversion unit 515 sets the value of the PreciseoriginTimestamp field of the Follow_Up message in IEEE802.1AS in the reserved field of the Sync message.

With reference to FIG. 12, (d) conversion between the 2-step Sync message of IEEE 1588-2019 and the 1-step Sync message of IEEE 802.1AS will be described.
If the message type of the sender is a Sync message in IEEE1588-2019, 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 Sync message of IEEE802.1AS.
On the other hand, when the message type of the sender is a Sync message in IEEE802.1AS, the protocol conversion unit 515 generates a Follow_Up message in IEEE1588-2019. 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.

(Step S34: Second conversion process)
The protocol conversion unit 515 adds or deletes a TLV field to or from the Announce message.

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

Here, the protocol conversion unit 515 configures the information of the PATH TRACE TLV 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 of the Announce message. Since the MAC addresses of 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 0).
As a specific example, the information of the PATH TRACE TLV is configured as shown in Fig. 13. Here, the stepRemoved information of the Announce message is set to N.

(Step S35: Third conversion process)
The protocol conversion unit 315 converts the items of the Pdelay_Req message.

A specific description will be given with reference to FIG.
If 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.

(Step S36: Fourth conversion process)
The protocol conversion unit 515 transmits a Delay_Resp message to the source.

A specific description will be given with reference to FIG.
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 transmit a Delay_Req message to the destination, but transmits a Delay_Resp message to the source.
At this time, the protocol conversion unit 515 sets the difference in delay value between the grandmaster and the 5G system calculated from the timestamp value acquired by the 5G system 100 in the receiveTimestamp field in the Delay_Resp message.

Here, the protocol conversion between IEEE1588-2019 and IEEE802.1AS has been described. However, it is possible to convert between other protocols according to the above-mentioned concepts. The above-mentioned concepts are the four concepts (S) to (V).
(S) The protocol conversion unit 515 converts a message with a TLV into a message without a TLV. In this case, the protocol conversion unit 515 deletes the TLV.
(T) The protocol conversion unit 515 converts a message without a TLV into a message with a TLV. In this case, the protocol conversion unit 515 sets a TLV 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 time stamp between the one-step synchronization message and the two-step synchronization message. 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 data type of the destination 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 data type of the destination, a Delay_Resp message is sent to the sender when a Delay_Req message is received.

The transmission information conversion process (step S4 in FIG. 5) according to the first embodiment will be described with reference to FIG.
(Step S41: Combination Determination Process)
The transmission processing unit 516 determines which combination in FIG. 7 the combination identified in step S2 is. 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.

(Step S42: A conversion process)
The transmission processing unit 516 converts the IP header and UDP header into DA, SA, and EtherType, as shown in Fig. 17. DA is an abbreviation for Destination MAC Address, SA is an abbreviation for Source MAC Address, and MAC is an abbreviation 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.

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

(Step S44: C conversion process)
The transmission processing unit 516 replaces the DA for Ethernet1588 with the DA for Ethernet1AS, as shown in FIG.

(Step S45: Digital conversion process)
The transmission processing unit 516 replaces the DA for Ethernet1AS with a DA for Ethernet1588, as shown in FIG.

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

(Step S47: F conversion process)
The F conversion process can be realized by a combination of the D conversion process and the B conversion process. Therefore, the transmission processing unit 516 performs the process of step S43 after performing the process of step S45. That is, after converting Ethernet1AS to Ethernet1588, it converts Ethernet1588 to IP1588.

***Advantages 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 PDU and Ethernet PDU with the UPF device 20. Then, the DS-TT device 50 uses the data type of the PTP message received via the PDU session 60 to identify the data type of the PTP message received from the 5G system 100 side. 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 translation function of the time synchronization message.

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

The DS-TT device 50 according to the first embodiment converts the configuration of the transmission information of the 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 convert the transmission information of the time synchronization message.

In the 5G system 100 according to the first embodiment, when the DS-TT device 50 receives a Delay_Req message in IEEE 1588-2019 when the destination protocol is IEEE 802.1AS, it transmits a Delay_Resp message to the sender. This makes it possible to respond appropriately to the Delay_Req message received from the sender.

***Other configurations***
<Modification 1>
In the first embodiment, each functional component is realized by software. However, as a first modification, each functional component may be realized by hardware. The following describes the first modification in terms of differences from the first embodiment.

When each functional component is realized by hardware, the UE 40 has an electronic circuit instead of the processor 41, the memory 42, and the storage 43. The electronic circuit is a dedicated circuit for realizing the functions of each functional component, the memory 42, and the storage 43.

When each functional component is realized by hardware, the DS-TT device 50 has an electronic circuit instead 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.

The electronic circuits may be a single circuit, a composite circuit, a programmed processor, a parallel programmed processor, a logic IC, a GA, an ASIC, or an FPGA. GA is an abbreviation for Gate Array. ASIC is an abbreviation for Application Specific Integrated Circuit. FPGA is an abbreviation for Field-Programmable Gate Array.
Each functional component may be realized by one electronic circuit, or each functional component may be realized by distributing it among a plurality of electronic circuits.

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

The processors 41 and 51, the memories 42 and 52, the storage 43 and 53, and the electronic circuitry are referred to as a processing circuit. In other words, the functions of each functional component are realized by the processing circuit.

In addition, the word "part" in the above description may be read as "circuit," "process," "procedure," "processing," or "processing circuit."

The above describes the embodiments and variations of the present disclosure. Some of these embodiments and variations may be combined and implemented. Also, one or some of them may be implemented partially. Note that the present disclosure is not limited to the above embodiments and variations, and various modifications are possible as necessary.

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 (8)

A DS-TT (Device-Side Time-sensitive networking Translator) device in 5GS (5 Generation System),
A DS-TT device including a protocol conversion unit that converts the contents of a message body of a Precision Time Protocol (PTP) message received via a PDU (Packet Data Unit) session established between a UE (User Equipment) and a UPF (User Plane Function) device, the PDU session including both information of an IP (Internet Protocol) PDU and an Ethernet PDU, in accordance with a combination of a data type of the PTP message and a data type of a destination of the PTP message. 2. The DS-TT device according to claim 1, wherein the protocol conversion unit converts the contents of the message body of the PTP message into contents that match the data type of the destination. 2. The DS-TT device according to claim 1, wherein the protocol conversion unit converts the contents of the message body in accordance with a message type of the PTP message. 3. The DS-TT device according to claim 2, wherein the protocol conversion unit transmits a reply message to the sender 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 further comprises:
A DS-TT device as described in any one of claims 1 to 4, further comprising a transmission processing unit that converts the configuration of transmission information indicating the destination and source of the PTP message according to the combination and then transmits it to the destination. 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 including 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. A UE (User Equipment) in 5GS (5 Generation System),
A UE including 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 including both IP (Internet Protocol) PDU (Packet Data Unit) and Ethernet PDU information between the UE and a User Plane Function (UPF) device. A message conversion method in a 5G (5 Generation) system,
A UE (User Equipment) establishes a PDU session including 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.