Method and device for time synchronization in a time synchronization domain

Abstract

To provide a time synchronization method for a time synchronization device.SOLUTION: A time synchronization device is connected to a plurality of time synchronization domains through a plurality of ports, and the time synchronization domains use a plurality of PTP profiles. The method comprises determining whether each of the ports is a time receiving port or a time transmitting port; obtaining information of a grandmaster clock of the time synchronization domains; performing information conversion on the information of the grandmaster clock according to a PTP profile corresponding to each time transmitting port of the ports in the PTP profiles, to generate multiple pieces of clock information corresponding to each time transmitting port; and transmitting corresponding clock information of the multiple pieces of clock information to a corresponding time synchronization domain from each time transmitting port, to perform time synchronization.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a method and a device for time synchronization, and more particularly, to a method and a device for time synchronization in a plurality of time synchronization network domains.

Background Art

[0002] PTP (Precision Time Protocol) is a standard for time synchronization defined by IEEE 1588 and is used to achieve high-precision time synchronization through time-critical networks. As the market evolves, different network applications have their own requirements. To address this, many different PTP profiles, such as Power Profile for power networks (IEEE Std C37.238), Telecom Profile for telecommunications networks (ITU-T G.8265.1), and Generalized Precision Time Protocol (gPTP, IEEE Std 802.1AS), have been proposed for different applications. PTP profiles enable applications in different fields to set specific operating parameters, attributes, and default values to meet these requirements. However, this can make it difficult for devices and networks using different PTP profiles to communicate effectively. Generally, to ensure time synchronization, devices or devices within the same environment must use the same PTP profile, making inter-domain time integration difficult.

[0003] Currently, gPTP defined by IEEE802.1AS is used to achieve accurate time synchronization in a time-sensitive network (TSN). The gPTP profile is one of the PTP profiles formulated according to IEEE1588 and is a simplified and optimized version of PTP for time-sensitive applications. However, under this protocol, all devices and network nodes need to support the gPTP profile to perform time synchronization in the TSN. This can be a problem for device manufacturers who need to update or modify devices that use other types of PTP profiles in order to use the gPTP profile. Therefore, there is a need for improvement in this field. Summary of the Invention

[0004] Therefore, the main object of the present invention is to provide a method for integrating multiple devices or networks that use different types of PTP profiles for time synchronization without affecting the accuracy of time synchronization in order to improve the drawbacks of the prior art.

[0005] Embodiments of the present invention disclose 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 ports, and the plurality of time synchronization domains use a plurality of PTP (Precision Time Protocol) profiles. The time synchronization method includes determining whether each of the plurality of ports is a time receiving port or a time transmitting port, obtaining information on the grandmaster clocks of the plurality of time synchronization domains, performing information conversion on the information on the grandmaster clocks according to the PTP profiles corresponding to the respective time transmitting ports of the plurality of ports in the plurality of PTP profiles to generate a plurality of clock information corresponding to the respective time transmitting ports of the plurality of ports, and transmitting the corresponding clock information of the plurality of clock information from each of the time transmitting ports of the plurality of ports to the corresponding time synchronization domain to perform time synchronization.

[0006] Embodiments of the present invention disclose a time synchronization device. The time synchronization device is connected to a plurality of time synchronization domains through a plurality of ports, and the plurality of time synchronization domains use a plurality of PTP (Precision Time Protocol) profiles. The time synchronization device includes a processing unit and a storage unit. The processing unit is configured to execute program code. The storage unit is coupled to the processing unit and is configured to store program code to instruct the processing unit to execute a time synchronization method. The time synchronization method includes determining whether each of the plurality of ports is a time receiving port or a time transmitting port, obtaining information on the grandmaster clocks of the plurality of time synchronization domains, performing information conversion on the information on the grandmaster clocks according to the PTP profiles corresponding to the respective time transmitting ports of the plurality of ports in the plurality of PTP profiles to generate a plurality of clock information corresponding to the respective time transmitting ports of the plurality of ports, and transmitting the corresponding clock information of the plurality of clock information from each of the time transmitting ports of the plurality of ports to the corresponding time synchronization domain to perform time synchronization.

[0007] The above and other objects of the present invention will become apparent to those skilled in the art after reading the following detailed description of the preferred embodiments shown in various figures and drawings.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Modes for Carrying Out the Invention

[0009] To indicate certain components, certain terms are used throughout the description and the following claims. As will be understood by those skilled in the art, hardware manufacturers may refer to components by different names. This document is not intended to distinguish between components that have different names but the same functions. In the following description and claims, the terms "include" and "comprise" are used in an open-ended manner and should therefore be construed to mean "including but not limited to".

[0010] Refer to FIG. 1 which is a schematic diagram of the network system 1. The network system 1 includes time synchronization domains 12_1 to 12_3. Each time synchronization domain may be a network domain composed of a wired network, a wireless network, or a combination thereof, may be a network domain composed of a plurality of devices, network switches, etc. (including a plurality of clocks), or may be a network domain composed of only a single device (including 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 (PTP) profiles A to C. It should be noted that since the time synchronization domains 12_1 to 12_3 operate the time synchronization mechanism according to different PTP profiles A to C, domain integration for time synchronization cannot be executed. In this situation, each time synchronization domain may have an optimal clock (such as the optimal clocks 14_1 to 14_3 in FIG. 1) for operating as the grandmaster (GM) clock of each time synchronization domain. In other words, devices belonging to the same network domain execute time synchronization according to the grandmaster clock of the network domain to which they belong. The optimal clock indicates the most ideal clock suitable for a specific time synchronization domain evaluated based on factors such as the time source, time accuracy, and oscillator stability, and may also be a clock determined by the user to be the most suitable for a specific time synchronization domain.In this situation, when a manufacturer attempts to replace or add a new device in a network domain, the new device must be compatible with the PTP profile used by the network domain. When a device manufacturer develops a device, customizations and adjustments for different types of PTP profiles should be performed separately so that it can be applicable in different fields. When a network domain needs to integrate with other specific time synchronization domains, updates for all devices and network devices may be required to be compatible with the gPTP (generalized Precision Time Protocol) profile.

[0011] In order to ensure that all devices within the network system 1 reach time synchronization based on the same grandmaster 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 to 12_3 to integrate the times of different time synchronization domains. Specifically, refer to FIG. 2, which is a schematic diagram of a time synchronization network system 2 according to an embodiment of the present invention. The time synchronization network system 2 includes time synchronization domains 12_1 to 12_3 and a time synchronization device 10. The time synchronization device 10 may be a network device such as a gateway, switch, router, or bridge operating within the network, but is not limited thereto. The time synchronization device 10 is connected to the time synchronization domains 12_1 to 12_3 through ports 16_1 to 16_3 respectively. In an embodiment of the present invention, the time synchronization domains 12_1 to 12_3 may perform time synchronization through the time synchronization device 10 according to a time synchronization method so that all devices and devices within the time synchronization domains 12_1 to 12_3 can be synchronized according to the grandmaster clock 14_1 of the specified network domain. Further, in the time synchronization network system 2, the number of time synchronization domains 12_1 to 12_3 is 3, but this is for illustrative purposes. The time synchronization device 10 according to an embodiment of the present invention may be applied to any number of time synchronization domains for time synchronization and is not limited thereto.

[0012] The time synchronization method of the present invention may be summarized in Process 3 as shown in FIG. 3, and Process 3 includes the following steps.

[0013] Step 300: Start.

[0014] Step 302: Determine whether each of the plurality of ports is a time receiving port or a time transmitting port.

[0015] Step 304: Obtain the information of the grandmaster clocks of the plurality of time synchronization domains.

[0016] Step 306: Perform information conversion on the information of the grandmaster clock according to the PTP profile corresponding to each time transmission port of the plurality of ports in the plurality of PTP profiles, and generate a plurality of clock information corresponding to each time transmission port of the plurality of ports.

[0017] Step 308: Transmit the corresponding clock information of the plurality of clock information from each time transmission port of the plurality of ports to the corresponding time synchronization domain to perform time synchronization.

[0018] Step 310: End.

[0019] According to Process 3, first, the time synchronization device 10 determines that each of the plurality of ports is a time reception port or a time transmission port (step 302). A time reception port refers to a port used to receive information such as a clock and time, or a port having a port state (portState) set to SlavePort according to the PTP specification. A time transmission port refers to a port used to transmit information such as a clock and time, or a port having a port state set to MasterPort according to the PTP specification. After determining that each port is a time reception port or a time transmission port, the time synchronization device 10 needs to further obtain information regarding the grandmaster clock (step 304). Therefore, the time synchronization device 10 performs information conversion on the information of the grandmaster clock according to the PTP profile corresponding to each time transmission port among the plurality of ports in the plurality of PTP profiles, generates clock information corresponding to each time transmission port (step 306), and then transmits the clock information from each time transmission port to the corresponding time synchronization domain (step 308) to synchronize the time. Therefore, all the time synchronization domains connected to the time synchronization device 10 may operate according to the time of the same grandmaster clock.

[0020] In other words, the time synchronization device 10 receives the clock-related information transmitted from the grandmaster clock through the time reception port, performs information conversion on the grandmaster clock information according to the PTP profile corresponding to the time transmission port, and then transmits the converted clock information through each time transmission port to the corresponding time synchronization domain. Therefore, all the devices and apparatuses in the time synchronization network system 2 may operate according to the time of the same grandmaster clock.

[0021] Specifically, taking FIG. 2 as an example, the time synchronization device 10 first determines that each of ports 16_1 to 16_3 is either a time reception port or a time transmission port. In an embodiment, the time synchronization device 10 first determines the PTP profile A of the time synchronization domain 12_1 to which the grandmaster clock 14_1 belongs, and then may compare it one by one with the PTP profiles corresponding to all the ports 16_1 to 16_3 of the time synchronization device 10. When the PTP profile corresponding to one of ports 16_1 to 16_3 is the same as the PTP profile A, that port is determined to be a time reception port (i.e., port 16_1), and the other ports (i.e., ports 16_2 and 16_3) are determined to be time transmission ports. Since the time reception port 16_1 receives clock-related information such as a notification message or a synchronization message transmitted from the grandmaster clock 14_1 of the time synchronization domain 12_1, the time synchronization device 10 may obtain information regarding the grandmaster clock through the time reception port 16_1. Further, the time synchronization device 10 needs to perform information conversion for the PTP profiles B and C respectively, 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 transmits the converted clock information to the corresponding time synchronization domains 12_1 and 12_3 through the time transmission ports 16_2 and 16_3 to synchronize the time.

[0022] As can be seen from the above, the time synchronization device 10 receives the information of the grandmaster clock 14_1 from the time synchronization domain 12_1 through the time reception port 16_1, and the information includes clock-related information and time information. Since the information of the grandmaster clock 14_1 received from the time synchronization domain 12_1 is the information transmitted according to the PTP profile A, the time synchronization device 10 needs to execute format and information conversion to generate information suitable for the network domains using different PTP profiles. Therefore, the time synchronization device 10 converts the information of the grandmaster clock 14_1 received by the time reception port 16_1 according to the PTP profiles B and C corresponding to the time synchronization domains 12_2 and 12_3 respectively, and finally transmits the time information after format conversion to the time synchronization domains 12_2 and 12_3 through the time transmission ports 16_2 and 16_3 respectively. Therefore, time synchronization between network domains using various types of PTP profiles can be achieved.

[0023] In FIG. 2, by using a single time synchronization device 10 and referring to process 3, the time synchronization network system 2 achieves synchronizing the time such that all time synchronization domains connected to the time synchronization device 10 operate according to the time of the same grandmaster clock. Those skilled in the art may make appropriate modifications according to the requirements of the system and are not limited thereto. For example, refer to FIG. 4 which is a schematic diagram of a time synchronization network system 4 according to an embodiment of the present invention. In this embodiment, the time synchronization network system 4 performs time synchronization of time synchronization domains 12_1 to 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 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 connection ports 46_3 and 46_4 respectively. Similar to the operation method of the time synchronization device 10, after determining the time synchronization domain to which the grandmaster clock 14_1 belongs, the time synchronization device 40_1 may determine the corresponding PTP profile A, whereby it is determined that port 46_1 is the time receiving port and port 46_2 is the time transmitting port. Therefore, through the time synchronization device 40_1, the information of the grandmaster clock 14_1 related to the PTP profile A may be received by the time receiving port 46_1, and the time information corresponding to the PTP profile B is transmitted to the time synchronization domain 12_1 through the time transmitting port 46_2 after information and format conversion. In this situation, the time synchronization domain 12_2 may be synchronized according to the grandmaster clock 14_1 located in the time synchronization domain 12_1. Correspondingly, since the information of the grandmaster 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 may determine that port 46_3 is the time receiving port and port 46_4 is the time transmitting port.Therefore, through the time synchronization device 40_2, the information of the grandmaster clock 14_1 related to the PTP profile B may be received by the time reception port 46_3, and then the time information corresponding to the PTP profile C is transmitted to the time synchronization domain 12_3 through the time transmission port 46_4 after information and format conversion. Therefore, the time synchronization network system 4 may achieve time synchronization for the time synchronization domains 12_1 to 12_3 by using two time synchronization devices 40_1 and 40_2.

[0024] Refer to FIG. 5, which is a schematic diagram of a time synchronization network system 5 according to an embodiment of the present invention. In this embodiment, the time synchronization network system 5 performs time synchronization of 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 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 connection ports 56_3 and 56_4 respectively. After determining the time synchronization domain to which the grandmaster clock 14_1 belongs, the time synchronization device 50_1 may determine the corresponding PTP profile A, whereby it is determined that port 56_1 is the time receiving port and port 56_2 is the time transmitting port. Through the time synchronization device 50_1, the information of the grandmaster clock 14_1 related to the PTP profile A may be received by the time receiving port 56_1, and then the time information corresponding to the PTP profile B is transmitted to the time synchronization domain 12_2 through the time transmitting port 56_2 after information and format conversion. Therefore, the time synchronization domain 12_2 may be synchronized according to the grandmaster clock 14_1 located in the time synchronization domain 12_1. Similarly, the time synchronization device 50_2 may determine that port 56_3 is the time receiving port and port 56_4 is the time transmitting port. Through the time synchronization device 50_2, the information of the grandmaster clock 14_1 related to the PTP profile A may be received by the time receiving port 56_3, and then the time information corresponding to the PTP profile C is transmitted to the time synchronization domain 12_3 through the time transmitting port 56_4 after information and format conversion. Therefore, the time synchronization network system 5 may achieve time synchronization for the time synchronization domains 12_1 to 12_3 by using two time synchronization devices 50_1 and 50_2.

[0025] In the above embodiment, the time synchronization device determines whether each of the ports is a time receiving port or a time transmitting port by comparing the PTP profile corresponding to the grandmaster clock with the PTP profiles corresponding to each port. In another embodiment, the clock of the time synchronization device may be the grandmaster clock. In other words, the grandmaster clock does not belong to any time synchronization domain connected to the time synchronization device. In this situation, time synchronization may still be performed according to Process 3. Refer to FIG. 6, which is a schematic diagram of the time synchronization network system 6 according to an embodiment of the present invention. The time synchronization network system 6 includes time synchronization domains 12_1 to 12_3 and a time synchronization device 60. In this embodiment, the time synchronization network system 6 uses the clock 64 of the time synchronization device 6 as the grandmaster clock and synchronizes the times of the time synchronization domains 12_1 to 12_3 accordingly. In this embodiment, the grandmaster clock 64 does not belong to any of the time synchronization domains 12_1 to 12_3 connected to the time synchronization device 60. Therefore, the time synchronization device 60 may determine that each of the ports 66_1 to 66_3 is a time transmitting port (step 302). Since the time synchronization device 60 does not have a time receiving port, the information of the grandmaster clock 64 is directly obtained from the time synchronization device 60 (step 304). Then, the time synchronization device 60 needs to perform information conversion on the PTP profiles A, B, and C used by the time synchronization domains 12_1 to 12_3 corresponding to the time transmitting 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 transmitted to the corresponding time synchronization domains 12_1 to 12_3 through the time transmitting ports 66_1 to 66_3 (step 308) to synchronize the times. Therefore, all of the time synchronization domains 12_1 to 12_3 may operate according to the time of the grandmaster clock 64 provided by the time synchronization device 60.

[0026] The time synchronization network systems 2, 4, 5, and 6 in the above embodiments include three time synchronization domains and one or two time synchronization devices, but it should be noted that these are for illustrative purposes. Embodiments of the present invention may be applied to any number or combination of time synchronization domains and time synchronization devices and are not limited thereto. Those skilled in the art should adopt an appropriate network topology according to actual requirements.

[0027] Furthermore, refer to FIG. 7, which is a schematic diagram of the network device 7 according to an embodiment of the present invention. The network device 7 may be, but is not limited to, a gateway, a switch, a router, or a bridge operating in the network. To implement the time synchronization devices 10, 40_1, 40_2, 50_1, 50_2, and 60 of the embodiments of the present invention, any network device 7 having a plurality of ports may be used. 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), or a combination thereof. The storage unit 72 is coupled to the processing unit 70 and may be any type of data storage device for storing the program code 720, and the program code 720 is read and executed by the processing unit 70. For example, the storage unit 72 may be, but is not limited to, a read-only memory (ROM), a flash memory, a random-access memory (RAM), a hard disk, an optical data storage device, a non-volatile storage unit, etc.

[0028] The network device 7 is used to represent the necessary components required to implement the embodiments of the present invention, and those skilled in the art may make various modifications and adjustments accordingly, not limited thereto. For example, when the network device 7 is applied to implement a time synchronization device, the process 3 for the time synchronization method may be compiled into the program code 720, stored in the storage unit 72, and executed by the processing unit 70. Further, the storage unit 72 is also used to store related information regarding the grandmaster clock, the PTP profile, and data necessary to execute the time synchronization method, not limited thereto.

[0029] In short, the present invention provides a time synchronization method and apparatus that realizes inter-domain time synchronization for a plurality of time synchronization domains using different PTP profiles and improves the lack of integration flexibility in the prior art.

[0030] Those skilled in the art can easily recognize that numerous modifications and changes to the devices and methods may be made while retaining the teachings of the present invention. Therefore, the above disclosure should be construed as being limited only by the boundaries of the appended claims.

Claims

1. A time synchronization method for a time synchronization device, wherein the time synchronization device is connected to a plurality of time synchronization domains through a plurality of ports, and the plurality of time synchronization domains use a plurality of PTP (Precision Time Protocol) profiles, the method comprising: determining whether each of the plurality of ports is a time receiving port or a time transmitting port; acquiring information on the grandmaster clocks of the plurality of time synchronization domains; performing information conversion on the information on the grandmaster clocks according to the PTP profiles corresponding to the respective time transmitting ports of the plurality of ports in the plurality of PTP profiles to generate a plurality of clock information corresponding to the respective time transmitting ports of the plurality of ports; transmitting the corresponding clock information of the plurality of clock information from each time transmitting port of the plurality of ports to the corresponding time synchronization domain to perform time synchronization; and the step of determining whether each of the plurality of ports is a time receiving port or a time transmitting port comprises: determining a first PTP profile of the time synchronization domain to which the grandmaster clock belongs; comparing the plurality of PTP profiles with the first PTP profile to generate a plurality of comparison results; and determining, according to the plurality of comparison results, that one of the plurality of ports is a time receiving port and the other ports are time transmitting ports. A time synchronization method.

2. The step of determining, according to the plurality of comparison results, that one of the plurality of ports is a time receiving port and the other ports are time transmitting ports comprises: when one of the plurality of comparison results indicates that the PTP profile corresponding to a port conforms to the first PTP profile, determining that the port is the time receiving port and determining that the other ports are the time transmitting ports. The time synchronization method according to Claim 1.

3. The step of acquiring the information on the grandmaster clocks of the plurality of time synchronization domains comprises: receiving the information on the grandmaster clocks from the time receiving port. The time synchronization method according to Claim 1.

4. The time synchronization method according to claim 1, wherein the time synchronization device is a gateway, a switch, a router, or a bridge.

5. The time synchronization method according to claim 1, wherein the plurality of PTP profiles are different.

6. A time synchronization device, wherein the time synchronization device is connected to a plurality of time synchronization domains through a plurality of ports, and the plurality of time synchronization domains use a plurality of PTP (Precision Time Protocol) profiles. The time synchronization device includes: A processing unit configured to execute program code; A storage unit coupled to the processing unit and configured to store the program code for instructing the processing unit to execute a time synchronization method. Including The time synchronization method includes: Determining whether each of the plurality of ports is a time receiving port or a time transmitting port; Obtaining information on the grandmaster clocks of the plurality of time synchronization domains; Performing information conversion on the information on the grandmaster clocks according to the PTP profiles corresponding to the respective time transmitting ports of the plurality of ports in the plurality of PTP profiles to generate a plurality of clock information corresponding to the respective time transmitting ports of the plurality of ports; Transmitting the corresponding clock information of the plurality of clock information from each time transmitting port of the plurality of ports to the corresponding time synchronization domain to perform time synchronization. Including The step of determining whether each of the plurality of ports is a time receiving port or a time transmitting port includes: Determining a first PTP profile of the time synchronization domain to which the grandmaster clock belongs; Comparing the plurality of PTP profiles with the first PTP profile to generate a plurality of comparison results; Determining, according to the plurality of comparison results, that one of the plurality of ports is a time receiving port and the other ports are time transmitting ports. A time synchronization device.

7. The step of determining, according to the plurality of comparison results, that one of the plurality of ports is a time receiving port and the other ports are time transmitting ports includes: When one of the plurality of comparison results indicates that the PTP profile corresponding to the port conforms to the first PTP profile, the step of determining that the port is the time receiving port and determining that the other port is the time transmitting port is included. The time synchronization device according to claim 6.

8. The step of obtaining the information of the grandmaster clock of the plurality of time synchronization domains includes The time synchronization device according to claim 6, including the step of receiving the information of the grandmaster clock from the time receiving port.

9. The time synchronization device according to claim 6, which is a gateway, switch, router or bridge.

10. The plurality of PTP profiles are different. The time synchronization device according to claim 6.

Images