TWI866115B - Method and device for time synchronization of time synchronization domains - Google Patents

Abstract

A time synchronization method for a time synchronization device is provided. The time synchronization device connects a plurality of time synchronization domains through a plurality of ports, and the plurality of time synchronization domains complies with a plurality of PTP profiles respectively. The time synchronization method includes determining each port of the plurality of ports to be a time receiving port or a time transmitting port; obtaining information of a grandmaster clock (GM) in the plurality of time synchronization domains; converting the information of the GM to generate a plurality of clock information corresponding to each time transmitting port of the plurality of ports according to the PTP profile of the plurality of PTP profiles corresponding to the each time transmitting port of the plurality of ports; and transmitting a corresponding clock information among the plurality of clock information to a corresponding time synchronization domain by each time transmitting port for time synchronization.

Description

Time synchronization domain time synchronization method and device

The present invention relates to a time synchronization method and device, and in particular to a time synchronization method and device for performing time synchronization in multiple time synchronization domains.

Precision Time Protocol (PTP) is a basic standard for time synchronization established by IEEE 1588, which is used to achieve high-precision clock synchronization. However, with the evolution of the market, applications in various networks have their own different requirements. Therefore, the previous technology proposed many different PTP profiles according to different applications, such as Power Profile (IEEE Std C37.238) for power networks, Telecom Profile (ITU-TG.8265.1) for telecommunications networks, and Generalized Precision Time Protocol (IEEE Std 802.1AS: Generalized Precision Time Protocol, gPTP) profiles. Profiles allow applications in different fields to set different operating parameters, properties, and default values to meet their needs, resulting in the inability of devices and networks using various different profiles to effectively communicate with each other. Generally speaking, in order to ensure time synchronization, devices or equipment in the same environment are required to use corresponding configuration files, making cross-domain time integration relatively difficult.

Currently, the protocol used to achieve accurate time synchronization in a time-sensitive network is regulated by the generalized precise time synchronization protocol defined by IEEE 802.1AS. The generalized precise time protocol profile (gPTP Profile) is also one of the profiles developed according to IEEE 1588. It simplifies PTP and optimizes it for time-sensitive applications. However, under this protocol, all devices and network nodes must support the gPTP profile in order to synchronize time on a time-sensitive network. In this case, equipment manufacturers need to update the equipment or modify all devices that use other types of profiles to use the gPTP profile, which causes great trouble. Therefore, there is a need to improve the known technology.

Therefore, the main purpose of the present invention is to provide a method for integrating multiple devices or networks using different types of precise time protocol configuration files for time synchronization without affecting the accuracy of time synchronization, so as to improve the shortcomings of the prior art.

The embodiment of the present invention discloses a time synchronization method for a time synchronization device. The time synchronization device is connected to a plurality of time synchronization domains through a plurality of connection ports. The plurality of time synchronization domains use a plurality of precise time protocol configuration files. The time synchronization method includes determining each of the plurality of ports as a time receiving port or a time transmission port; obtaining information of a master clock in the plurality of time synchronization domains; converting the information of the master clock according to the precise time protocol configuration files corresponding to each time transmission port of the plurality of ports in the plurality of precise time protocol configuration files to generate a plurality of clock information corresponding to each time transmission port of the plurality of ports; and transmitting a corresponding clock information in the plurality of clock information to a corresponding time synchronization domain by each time transmission port of the plurality of ports to perform time synchronization.

The present invention also discloses a time synchronization device, wherein the time synchronization device is connected to a plurality of time synchronization domains through a plurality of connection ports, and the plurality of time synchronization domains use a plurality of precise time protocol configuration files. The time synchronization device includes a processing unit for executing a program code; and a storage unit coupled to the processing unit for storing the program code to instruct the processing unit to execute a time synchronization method. The time synchronization method includes determining each of the plurality of ports as a time receiving port or a time transmission port; obtaining information of a master clock in the plurality of time synchronization domains; converting the information of the master clock according to the precise time protocol configuration files corresponding to each time transmission port of the plurality of ports in the plurality of precise time protocol configuration files to generate a plurality of clock information corresponding to each time transmission port of the plurality of ports; and transmitting a corresponding clock information in the plurality of clock information to a corresponding time synchronization domain by each time transmission port of the plurality of ports to perform time synchronization.

1: Network system

12_1~12_3: Time synchronization domain

14_1~14_3: Best local clock

A, B, C: Precision Time Protocol configuration files

2, 4, 5, 6: Time synchronization network system

10: Time synchronization device

16_1~16_3: Connection port

3: Process

300~314: Steps

40_1, 40_2: Time synchronization device

40_1~40_4: Connection port

50_1, 50_2: Time synchronization device

50_1~50_4: Connection port

60: Time synchronization device

60_1~60_3: Connection port

64: Main clock

7: Network devices

70: Processing unit

72: Storage unit

720:Program code

Figure 1 is a schematic diagram of a network system.

Figure 2 is a schematic diagram of a time synchronization network system according to an embodiment of the present invention.

Figure 3 is a schematic diagram of the process of the time synchronization method of the first embodiment of the present invention.

Figure 4 is a schematic diagram of a time synchronization network system including two time synchronization devices according to an embodiment of the present invention.

Figure 5 is a schematic diagram of a time synchronization network system including two time synchronization devices according to an embodiment of the present invention.

Figure 6 is a schematic diagram of a time synchronization network system that synchronizes the time of a time synchronization device in an embodiment of the present invention.

Figure 7 is a schematic diagram of a network device according to an embodiment of the present invention.

Certain terms are used in this specification and subsequent patent applications to refer to specific components. A person with ordinary knowledge in the field should understand that hardware manufacturers may use different terms to refer to the same component. This specification and subsequent patent applications do not use differences in names as a way to distinguish components, but rather use differences in components' functions as the criteria for distinction. The term "including" mentioned throughout the specification and subsequent patent applications is an open term and should be interpreted as "including but not limited to".

Please refer to FIG. 1, which is a schematic diagram of a network system 1. The network system 1 includes time synchronization domains 12_1 to 12_3, wherein each time synchronization domain can be a domain composed of a wired network, a wireless network, or a combination of the two, and can be a domain composed of multiple devices and multiple network switches (including multiple clocks), or a domain composed of only a single device (only one clock). The time synchronization domains 12_1 to 12_3 are time synchronization domains that operate according to the specifications of different types of Precision Time Protocol Profiles (PTP Profiles) A to C. It should be noted that, since the time synchronization domains 12_1~12_3 run the time synchronization mechanism according to different precise time protocol configuration files A~C, time synchronization integration across domains cannot be performed. In this case, each time synchronization domain has a best clock (such as the best clock 14_1~14_3 in FIG. 1) running as the master clock (Grandmaster, GM) of each time-sensitive network domain, that is, the devices belonging to the same domain are all synchronized according to the master clock of the domain to which they belong. Among them, the best clock refers to the most ideal clock suitable for a specific time synchronization domain evaluated based on factors such as time source, time accuracy, and oscillator stability, and can also be determined by humans as the most suitable clock for a specific time synchronization domain. In this case, when a vendor wants to replace or add a new device in a domain, the new device must be compatible with the precise time protocol profile used by the domain to which it belongs; when a device vendor develops a device, it must customize or adjust the device for various precise time protocol profiles before it can be applied to different domains; when the domain to which it belongs wants to integrate with other specific time synchronization domains, it may be necessary to upgrade all devices and network devices to be compatible with the general precise time protocol profile.

In order to enable all devices in the network system 1 to achieve time synchronization based on the same master clock without affecting the accuracy of time synchronization, the present invention provides a time synchronization device that can be connected to the time synchronization domains 12_1~12_3 to integrate the time of different time synchronization domains. For details, please refer to Figure 2, which is a schematic diagram of a time synchronization network system 2 of an embodiment of the present invention. The time synchronization network system 2 includes time synchronization domains 12_1~12_3 and a time synchronization device 10. The time synchronization device 10 can be a network device such as a gateway, a switch, a router, and a bridge running in the network, but is not limited thereto. The time synchronization device 10 is connected to the time synchronization domains 12_1~12_3 through the connection ports 16_1~16_3 respectively. In the embodiment of the present invention, the time synchronization domains 12_1~12_3 can be synchronized through the time synchronization device 10 according to a time synchronization method, so that all equipment and devices in the time synchronization domains 12_1~12_3 are synchronized according to the time of the master clock 14_1 of the specified domain. In addition, in the time synchronization network system 2, the number of time synchronization domains 12_1~12_3 is 3, which is only for illustrative purposes. The time synchronization device 10 of the embodiment of the present invention can be applied to time synchronization between any number of time synchronization domains, but is not limited to this.

The time synchronization method of the embodiment of the present invention can be summarized as a process 3, as shown in Figure 3, process 3 includes the following steps:

Step 300: Start.

Step 302: Determine whether each of the plurality of ports is a time receiving port or a time transmitting port.

Step 304: Obtain information of a master clock in a plurality of time synchronization domains.

Step 306: According to the precise time protocol configuration files corresponding to each time transmission port of the plurality of connection ports in the plurality of precise time protocol configuration files, the information of the master clock is converted to generate a plurality of clock information corresponding to each time transmission port of the plurality of connection ports.

Step 308: Each time transmission port of the plurality of connection ports transmits a corresponding clock information in the plurality of clock information to a corresponding time synchronization domain for time synchronization.

Step 310: End.

According to process 3, the time synchronization device 10 first determines that a plurality of ports are a time receiving port or a time transmitting port (step 302). The time receiving port refers to a port for receiving information related to the clock and time, or a port whose port state (portState) is set as a SlavePort according to the specification of the precise time protocol; the time transmitting port refers to a port for transmitting information related to the clock and time, or a port whose port state is set as a MasterPort according to the specification of the precise time protocol. After determining that each port is a time receiving port or a time transmitting port, the time synchronization device 10 needs to further obtain information related to the master clock (step 304). Accordingly, the time synchronization device 10 needs to convert the information of the master clock according to the precise time protocol configuration files corresponding to each time transfer port in the plurality of precise time protocol configuration files to generate clock information corresponding to each time transfer port (step 306), and then send the clock information from each time transfer port to the corresponding time synchronization domain (step 308) to synchronize the time. Accordingly, all time synchronization domains connected to the time synchronization device 10 can be operated according to the time of the same master clock.

In other words, the time synchronization device 10 receives the clock-related information sent from the master clock through the time receiving port, converts the master clock information according to the precise time protocol configuration file corresponding to the time transmission port, and then sends the converted clock information to the corresponding time synchronization domain through each time transmission port. In this way, all equipment and devices in the time synchronization network system 2 can operate according to the time of the same master clock.

In detail, taking FIG. 2 as an example, the time synchronization device 10 first determines each port 16_1 to 16_3 as a time receiving port or a time transmitting port. In one embodiment, the time synchronization device 10 may first determine the precise time protocol configuration file A of the time synchronization domain 12_1 to which the master clock 14_1 belongs, and then compare the precise time protocol configuration files corresponding to all ports 16_1 to 16_3 of the time synchronization device 10 one by one. When the precise time protocol configuration file corresponding to one of the ports 16_1 to 16_3 is the same as the precise time protocol configuration file A, the port is determined to be a time receiving port (i.e., port 16_1), and the remaining ports (i.e., ports 16_2 and 16_3) are determined to be time transmitting ports. Since the time receiving port 16_1 receives the clock-related information sent from the master clock 14_1 in the time synchronization domain 12_1, such as the announce message and the sync message, the time synchronization device 10 can obtain the information related to the master clock through the time receiving port 16_1. Furthermore, the time synchronization device 10 needs to perform information conversion for the precise time protocol configuration files B and C, that is, for the time synchronization domains 12_2 and 12_3 corresponding to the time transmission ports 16_2 and 16_3, to generate clock information corresponding to the time synchronization domains 12_2 and 12_3. Finally, the time synchronization device 10 sends the converted clock information to the corresponding time synchronization domains 12_2 and 12_3 through the time transmission ports 16_2 and 16_3 to synchronize the time.

As can be seen from the above, the time synchronization device 10 receives information from the master clock 14_1 of the time synchronization domain 12_1 through the time receiving port 16_1, which includes clock-related information and time information. The information of the master clock 14_1 received by the time synchronization domain 12_1 is information transmitted according to the precise time protocol configuration file A, so it is necessary to perform format and information conversion through the time synchronization device 10 to generate a domain suitable for using different precise time protocol configuration files. Therefore, the time synchronization device 10 converts the information of the master clock 14_1 received by the time receiving port 16_1 according to the precise time protocol configuration files B and C corresponding to the time synchronization domains 12_2 and 12_3, and finally sends the converted time information to the time synchronization domains 12_2 and 12_3 through the time transmission ports 16_2 and 16_3. In this way, time synchronization can be performed across various domains using different precise time protocol configuration files.

In FIG. 2, using a single time synchronization device 10 and according to process 3, the time synchronization network system 2 can achieve that all time synchronization domains connected to the time synchronization device 10 are operated according to the time of the same master clock, thereby synchronizing the time. A person skilled in the art can make appropriate changes according to the needs of the system, but is not limited to this. For example, please refer to FIG. 4, which is a schematic diagram of the time synchronization network system 4 of the first embodiment of the present invention. In this embodiment, the time synchronization network system 4 performs time synchronization of the time synchronization domains 12_1~12_3 through two time synchronization devices 40_1 and 40_2. The time synchronization device 40_1 is connected to the time synchronization domains 12_1 and 12_2 through the ports 46_1 and 46_2, respectively, and the time synchronization device 40_2 is connected to the time synchronization domains 12_2 and 12_3 through the ports 46_3 and 46_4, respectively. Similar to the operation of the time synchronization device 10, after determining the time synchronization domain to which the master clock 14_1 belongs, the time synchronization device 40_1 can determine the corresponding accurate time protocol configuration file A, and accordingly determine the port 46_1 as a time receiving port and the port 46_2 as a time transmitting port. Therefore, through the time synchronization device 40_1, the information of the master clock 14_1 related to the precise time protocol profile A can be received by the time receiving port 46_1, and after the information and format conversion, the time information corresponding to the precise time protocol profile B is sent to the time synchronization domain 12_2 through the time transmission port 46_2. In this case, the time synchronization domain 12_2 can be synchronized according to the master clock 14_1 located in the time synchronization domain 12_1. Correspondingly, since the master clock 14_1 is transmitted to the time synchronization device 40_2 through the time synchronization domain 12_2, the time synchronization device 40_2 can determine the connection port 46_3 as a time receiving port and the connection port 46_4 as a time transmission port. Therefore, through the time synchronization device 40_2, the information of the master clock 14_1 related to the precise time protocol configuration file B can be received by the time receiving port 46_3, and after the information and format conversion, the time information corresponding to the precise time protocol configuration file C is sent to the time synchronization domain 12_3 through the time transmission port 46_4. Accordingly, the time synchronization network system 4 can use the two time synchronization devices 40_1 and 40_2 to achieve time synchronization of the time synchronization domains 12_1~12_3.

Please refer to FIG. 5, which is a schematic diagram of a time synchronization network system 5 of the first embodiment of the present invention. In this embodiment, the time synchronization network system 5 performs time synchronization of the time synchronization domains 12_1 to 12_3 through two time synchronization devices 50_1 and 50_2. The time synchronization device 50_1 is connected to the time synchronization domains 12_1 and 12_2 through the connection ports 56_1 and 56_2, respectively, and the time synchronization device 50_2 is connected to the time synchronization domains 12_1 and 12_3 through the connection ports 56_3 and 56_4, respectively. After determining the time synchronization domain to which the master clock 14_1 belongs, the time synchronization device 50_1 can determine the corresponding precise time protocol profile A, and accordingly determine the connection port 56_1 to be a time receiving port and the connection port 56_2 to be a time transmitting port. Through the time synchronization device 50_1, the information of the master clock 14_1 related to the precise time protocol profile A can be received by the time receiving port 56_1, and after the information and format conversion, the time information corresponding to the precise time protocol profile B is sent to the time synchronization domain 12_2 through the time transmitting port 56_2. In this way, the time synchronization domain 12_2 can be synchronized according to the master clock 14_1 located in the time synchronization domain 12_1. Similarly, the time synchronization device 50_2 can determine that the connection port 56_3 is a time receiving port and the connection port 56_4 is a time transmitting port. Through the time synchronization device 50_2, the information of the master clock 14_1 related to the precise time protocol configuration file A can be received by the time receiving port 56_3, and after the information and format conversion, the converted time information corresponding to the precise time protocol configuration file C is sent to the time synchronization domain 12_3 through the time transmission port 56_4. Accordingly, the time synchronization network system 5 can use the two time synchronization devices 50_1 and 50_2 to achieve time synchronization of the time synchronization domains 52_1~52_3.

In the aforementioned embodiment, the time synchronization device determines each port as a time receiving port or a time transmitting port by comparing the precise time protocol configuration file corresponding to the master clock with the precise time protocol configuration file corresponding to each port. In another embodiment, the time synchronization device may be the master clock, in other words, the master clock does not belong to any time synchronization domain connected to the time synchronization device. In this case, time synchronization can still be performed according to process 3. Please refer to Figure 6, which is a schematic diagram of a time synchronization network system 6 of an embodiment of the present invention. The time synchronization network system 6 includes time synchronization domains 12_1~12_3 and a time synchronization device 60. In this embodiment, the time synchronization network system 6 uses a clock 64 of the time synchronization device 60 as the master clock, and synchronizes the time of the time synchronization domains 12_1~12_3 accordingly. In this embodiment, the master clock 64 does not belong to any of the time synchronization domains 12_1~12_3 connected to the time synchronization device 60, so the time synchronization device 60 can set all the connection ports 66_1~66_3 as time transmission ports (step 302). Since the time synchronization device 60 does not have a time receiving port, the information of the master clock 64 is directly obtained by the time synchronization device 60 itself (step 304). Next, the time synchronization device 60 needs to convert the precise time protocol configuration files A, B, and C used by the time synchronization domains 12_1 to 12_3 corresponding to the time transmission ports 66_1 to 66_3 to generate clock information corresponding to the time synchronization domains 12_1 to 12_3 (step 306). Finally, the converted clock information is sent to the corresponding time synchronization domains 12_1 to 12_3 via the time transmission ports 66_1 to 66_3 (step 308) to synchronize the time. Accordingly, all time synchronization domains 12_1 to 12_3 connected to the time synchronization device 60 can operate according to the time of the master clock 64 provided by the time synchronization device 60.

In addition, it should be noted that the time synchronization network systems 2, 4, 5, and 6 in the above embodiments include 3 time synchronization domains and 1 or 2 time synchronization devices, which are for illustrative purposes only. The embodiments of the present invention can be applied to the time synchronization of any number or combination of time synchronization domains and time synchronization devices, but are not limited thereto. A person with ordinary knowledge in the field can adopt an appropriate network topology according to actual needs.

Further, please refer to FIG. 7, which is a schematic diagram of a network device 7 of an embodiment of the present invention. The network device 7 may be a network device such as a gateway, a switch, a router, and a bridge operating in a time-sensitive network, but is not limited thereto. Any network device 7 with multiple connection ports can be used to implement the time synchronization devices 10, 40_1, 40_2, 50_1, 50_2, and 60 of the embodiment of the present invention. As shown in FIG. 7, the network device 7 may include a processing unit 70 and a storage unit 72. The processing unit 70 may be a general-purpose processor, a microprocessor, an application-specific integrated circuit (ASIC), etc., or a combination thereof. The storage unit 72 is coupled to the processing unit 70 and can be any data storage device for storing a program code 720, and reading and executing the program code 720 through the processing unit 70. For example, the storage unit 72 can be a read-only memory (ROM), a flash memory, a random access memory (RAM), a hard disk, an optical data storage device, and a non-volatile storage unit, but is not limited thereto.

The network device 7 is used to represent the necessary components required to implement the embodiment of the present invention. A person with ordinary knowledge in the field can make different modifications and adjustments based on it, but it is not limited to this. For example, when the network device 7 is used to implement the time synchronization device, the process 3 of the time synchronization method can be compiled into a program code 720 and stored in the storage unit 72, and the processing unit 70 executes the time synchronization method. In addition, the storage unit 72 is also used to store the main clock related information, the precise time protocol configuration file and the data required for the operation of the time synchronization method, but it is not limited to this.

In summary, the present invention provides a time synchronization method and device, which can perform cross-domain time synchronization in multiple time synchronization domains using different precise time protocol configuration files, improving the shortcomings of the known technology of lack of integration flexibility.

The above is only the preferred embodiment of the present invention. All equivalent changes and modifications made according to the scope of the patent application of the present invention shall fall within the scope of the present invention.

2: Time synchronization network system

10: Time synchronization device

12_1~12_3: Time synchronization domain

14_1~14_3: Best local clock

16_1~16_3: Connection port

A, B, C: Precision Time Protocol configuration files

Claims (14)

A time synchronization method is used for a time synchronization device. The time synchronization device is connected to a plurality of time synchronization domains through a plurality of connection ports. The plurality of time synchronization domains use a plurality of precision time protocol profiles (PTP Profiles). The time synchronization method includes: determining each of the plurality of connection ports to be a time receiving port or a time transmitting port; obtaining information of a grandmaster (GM) in the plurality of time synchronization domains; performing information conversion on the information of the grandmaster according to the precision time protocol profiles corresponding to each time transmitting port of the plurality of connection ports in the plurality of precision time protocol profiles to generate a plurality of clock information corresponding to each time transmitting port of the plurality of connection ports; and transmitting a plurality of clock information corresponding to each time transmitting port of the plurality of connection ports by each time transmitting port of the plurality of connection ports. Sending a corresponding clock information from the plurality of clock information to a corresponding time synchronization domain for time synchronization; wherein the step of determining each of the plurality of ports as a time receiving port or a time transmitting port comprises: determining a first precise time protocol configuration file of a time synchronization domain to which the master clock belongs; comparing the plurality of precise time protocol configuration files with the first precise time protocol configuration file to generate a plurality of comparison results; and determining one of the plurality of ports as a time receiving port and determining the other ports as time transmitting ports based on the plurality of comparison results. The time synchronization method as described in claim 1, wherein the step of determining one of the plurality of ports as a time receiving port and determining the other ports as time transmitting ports according to the plurality of comparison results is to determine that the port is the time receiving port and determine the other ports as time transmitting ports when one of the plurality of comparison results shows that a precise time protocol configuration file corresponding to a port meets the first precise time protocol configuration file. The time synchronization method as described in claim 1, wherein the step of obtaining the information of the master clock in the plurality of time synchronization domains includes receiving the information of the master clock from the time receiving port. The time synchronization method as described in claim 1, wherein the step of determining each of the plurality of ports to be a time receiving port or a time transmitting port includes determining each of the plurality of ports to be a time transmitting port when a clock of the time synchronization device is the master clock. The time synchronization method as described in claim 4, wherein the step of obtaining the information of the master clock is to obtain the information of the master clock by the time synchronization device. A time synchronization method as described in claim 1, wherein the time synchronization device is a network gateway, a network switch, a router or a bridge. A time synchronization method as described in claim 1, wherein the plurality of precise time protocol profiles are different. A time synchronization device, wherein the time synchronization device is connected to a plurality of time synchronization domains through a plurality of connection ports, and the plurality of time synchronization domains use a plurality of Precision Time Protocol Profile (PTP) Profile), the time synchronization device comprises: a processing unit for executing a program code; and a storage unit coupled to the processing unit for storing the program code to instruct the processing unit to execute a time synchronization method, the time synchronization method comprising: determining each of the plurality of ports to be a time receiving port or a time transmitting port; obtaining information of a master clock (Grandmaster, GM) in the plurality of time synchronization domains; performing information conversion on the information of the master clock according to the precise time protocol configuration file corresponding to each time transmitting port of the plurality of ports in the plurality of precise time protocol configuration files to generate information corresponding to the plurality of ports A plurality of clock information of each time transmission port; and each time transmission port of the plurality of connection ports transmits a corresponding clock information of the plurality of clock information to a corresponding time synchronization domain for time synchronization; wherein, the step of determining each connection port of the plurality of connection ports as a time receiving port or a time transmission port comprises: determining a first precise time protocol configuration file of a time synchronization domain to which the master clock belongs; comparing the plurality of precise time protocol configuration files with the first precise time protocol configuration file to generate a plurality of comparison results; and determining one of the plurality of connection ports as a time receiving port and determining the other connection ports as time transmission ports according to the plurality of comparison results. The time synchronization device as described in claim 8, wherein the step of determining one of the plurality of ports as a time receiving port and determining the other ports as time transmitting ports according to the plurality of comparison results is to determine that the port is the time receiving port and determine the other ports as time transmitting ports when one of the plurality of comparison results shows that a precise time protocol configuration file corresponding to a port matches the first precise time protocol configuration file. The time synchronization device as described in claim 8, wherein the step of obtaining the information of the master clock in the plurality of time synchronization domains includes receiving the information of the master clock from the time receiving port. The time synchronization device as described in claim 8, wherein the step of determining whether each of the plurality of ports is a time receiving port or a time transmitting port includes determining that each of the plurality of ports is a time transmitting port when a clock of the time synchronization device is the master clock. The time synchronization device as described in claim 11, wherein the step of obtaining the information of the master clock is to obtain the information of the master clock by the time synchronization device. The time synchronization device as described in claim 8 is a network gateway, a network switch, a router or a bridge. A time synchronization device as described in claim 8, wherein the plurality of precise time protocol configuration files are different.

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