Method for determining time source, and network equipment

[0046] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts shall fall within the protection scope of the present invention.

[0047] The terms "component", "module", "system" and the like are used in this specification to refer to a computer-related entity, hardware, firmware, a combination of hardware and software, software, or software in execution. For example, a component may be, but is not limited to being, a process running on a processor, a processor, an object, an executable, a thread of execution, a program, and/or a computer. By way of illustration, both an application running on a computing device and the computing device can be components. One or more components can reside within a process and/or thread of execution and a component can be localized on one computer and/or distributed between two or more computers. In addition, these components can execute from various computer readable media having various data structures stored thereon. A component may, for example, be based on a signal having one or more packets of data (e.g., data from two components interacting with another component between a local system, a distributed system, and/or a network, such as the Internet via a signal interacting with other systems). Communicate through local and/or remote processes.

[0048] It should be understood that the technical solutions in the embodiments of the present invention can be applied to various communication systems, for example: Global System of Mobile Communication (GSM for short) system, Code Division Multiple Access (CDMA for short) ) system, Wideband Code Division Multiple Access (WCDMA for short) system, Long Term Evolution (LTE for short) system, Frequency Division Duplex for LTE (FDD for short) system, LTE Time Division Duplex (Time Division Duplex, referred to as "TDD"), Universal Mobile Telecommunications System (Universal Mobile Telecommunications System, referred to as "UMTS"), and future 5G communication systems.

[0049] The network device in the embodiment of the present invention may be a device for communicating with a terminal device, for example, it may be a base station (Base Transceiver Station, "BTS" for short) in a GSM system or a CDMA system, or it may be a base station in a WCDMA system (NodeB, referred to as "NB"), or an evolved base station (Evolutional Node B, referred to as "eNB" or "eNodeB") in the LTE system, or the network device can be a relay station, access point, vehicle-mounted device, or Wearable devices and network-side devices in the future 5G network or network devices in the future evolved PLMN network, etc.

[0050] In a communication network, the normal operation of many services requires network clock synchronization, that is, the time or frequency difference between devices in the entire network is kept within a reasonable error level. Time synchronization (Phase Synchronization) means that the frequency and phase between the signals are consistent, that is, the phase difference between the signals is always zero.

[0051] figure 1 is a schematic diagram of an application scenario of an embodiment of the present invention. figure 1 It shows at least one network device (or called time device, device), including BC devices 11 to 16 at the convergence layer, BC devices 17 and 18 at the access layer, and an ordinary clock (Ordinary Clock, referred to as "OC") device 19, base stations NodeB 20 and NodeB 21, and atomic global positioning system (ATOM GPS) 22 and ATOM GPS 23, wherein ATOM GPS 22 is the main time source device, and ATOM GPS 23 is the backup time source device. figure 1 It is only a simplified schematic diagram of an example, and other types of network devices may also be included in the network. figure 1 not drawn in.

[0052]If the optical module of ATOM GPS 22 fails, network equipment such as BC equipment will report a source switching event and a time out of lock alarm during the process of reselecting the source to track the port where the optical module of the standby ATOM GPS 21 is located. Afterwards, if the original ATOMGPS 22 optical module fails, or a new high-priority ATOM GPS optical module is reinserted, the BC device will reselect the source tracking high-priority ATOM GPS optical module again. In this scenario, if the time sources provided by ATOM GPS 22 and ATOMGPS 23 both come from GPS satellite signals, and key parameters such as time source accuracy, stability, and phase are equivalent, then the process of time source switching has no actual benefits , on the contrary, related events and alarms will be reported, which increases unnecessary explanation and maintenance costs, and the process of source cutting may also be accompanied by time jumps and degradation of performance.

[0053] The embodiment of the present invention compares the current time source of the network device with the time source obtained from other network devices, and does not switch the time source when the information of the two time sources is the same, thereby avoiding the additional time source switching caused by unnecessary time source overhead.

[0054] figure 2 A schematic flowchart of a method for determining a time source according to an embodiment of the present invention is shown. In this method, the time source switching of the first device is used as an example for illustration. For example, the first device may be figure 1 Any of the network devices shown in . The methods for determining the time source include:

[0055] S210. The first network device using the first time source acquires time source information of the second time source used by the second network device.

[0056] S220. If the time source information of the second time source is the same as the time source information of the first time source, prohibit the first network device from switching the time source of the first network device from the first time source to the second time source.

[0057] Specifically, the time source currently used by the first network device is the first time source. When a second time source occurs, such as when a new time source device is inserted into the network or the function of the original main time source device is restored, the prior art The first network device needs to perform a source selection process to reselect a better time source and perform time source switching. For example, the first network device can follow the source selection process of the best master clock (Best Master Clock, referred to as "BMC"), Select and switch the time source. However, if the time source information of the second time source is the same as the time source information of the first time source, the first network device may not select and switch the time source in this embodiment of the present invention.

[0058] The second network device sends the time source information of the second time source used by the second network device to the first network device using the first time source, so that the time source information of the second time source of the first network device is the same as that of the first time source. When the time source information of the time source is the same, the time source of the first network device is not switched from the first time source to the second time source.

[0059] For example, the network device that has already tracked and locked time source A obtains another available time source B. At this time, the network device needs to determine whether the new time source B is the same source as the currently tracked time source A (for example, two Both time sources come from the GPS satellite system); if time source B and time source A are homologous, then the network device does not need to switch the source to track time source B, even if the priority of time source B is higher than that of time source A .

[0060] Optionally, the method may further include: if the time source information of the second network device is different from that of the first time source, the first network device determines the optimal time source among the first time source and the second time source time source, and switch the time source of the first network device from the first time source to the optimal time source.

[0061] Specifically, if the time source information of the second time source is different from the time source information of the first time source, S220 is not performed, but the optimal time source is determined among the first time source and the second time source, for example, by The BMC source selection algorithm realizes the determination of the optimal time source, and switches the time source of the first network device from the first time source to the optimal time source.

[0062] Optionally, the first time source information includes the time source ID of the first time source and the hop count of the first time source; the second time source information includes the time source ID of the second time source and the hop count of the second time source .

[0063] Wherein, the time source ID of the first time source is used to identify the first time source, and the time source ID of the second time source is used to identify the second time source.

[0064] Wherein, the hop count of the time source of the first network device represents the number of network elements passed by the time source of the first network device in the network, and the hop count of the time source of the second network device represents The number of network elements passed by the time source of the first network device to the second network device in the network.

[0065] Specifically, the first network device may determine whether to perform time source switching according to the time source information of the first time source currently used by the first network device and the time source information of the second time source used by the second network device, that is, Whether to switch the time source of the first network device from the first time source to the second time source. After the first network device obtains the time source information of the second time source, if it is determined that the time source information of the second time source is the same as the time source information of the first time source, it can be considered that the first time source and the second time source come from If they are based on the same time source device such as the GPS satellite system, then their synchronization time should also be the same, so there is no need to switch the time source, that is, there is no need to switch the time source currently used by the first network device from the first time source as the second time source.

[0066] It should be noted that one condition for not performing time source switching mentioned here is that the time source ID of the first time source is the same as the time source ID of the second time source. The time source ID of the first time source and the time source ID of the second time source are the same, indicating that the first time source and the second time source are consistent, that is, both the first time source and the second time source come from the same time For example, the source devices all come from GPS satellites, or both come from Beidou satellites, or come from the same independent atomic clock. At this time, the first time source and the second time source should not only ensure the same accuracy and stability of the time source, but also have the same key parameters such as phase. If the first time source currently used by the first network device and the second time source from the second network device come from two different time source devices (for example, the first time source comes from GPS satellites, and the second time source source from the Beidou satellite), then even if the time source accuracy and stability of these two different time source devices are consistent, they do not meet the requirements of consistent time sources, because there is no guarantee that the phases of the first time source and the second time source are the same Consistent, even if the aspect is the same at this moment, there is no guarantee that the aspect will remain the same in the future.

[0067] It should also be understood that different time source IDs are used to identify different time sources, and the same time source ID represents a unique time source, that is, one time source ID is used to identify one independent time source.

[0068] For example, in general, an independent time source corresponding to a time source ID, and other time sources other than the independent time source come from different time source devices and their accuracy, stability, phase parameters are not exactly the same. For example, the first time source is from the first atomic clock, and the second time source is from the second atomic clock, then the accuracy, stability or phase of the first time source from the first atomic clock and the second time source from the second atomic clock If the parameters are different, the time source ID of the first time source and the time source ID of the second time source are different. For example, the time source ID of the first time source from the first atomic clock is 1, and the time source ID of the second time source from the second atomic clock is The time source ID of the time source is 2. But there is a situation, if all the parameters from the first time source of the first atomic clock and the second time source of the second atomic clock are the same, then the first time source and the second time source are exactly the same time source, the first The time source ID of the time source and the time source ID of the second time source are the same time source ID. For example, if the frequency, phase and other parameters of the first time source are adjusted to a fixed value, and the frequency and phase parameters of the second time source are also adjusted to the same parameter value, then the first time source and the second time source The second time source is exactly the same time source, that is, the frequency, accuracy, stability, or phase of the first time source and the second time source are consistent, so the time source IDs of the first time source and the second time source are also identical.

[0069] Because the accuracy and stability of the time source can be transmitted to downstream devices, but even if the accuracy and stability are the same, the same source cannot be guaranteed. Therefore, a new parameter is proposed in the embodiment of the present invention, that is, the time source ID. To characterize the uniqueness of each time source, and can be passed to downstream devices.

[0070] The difference from the existing Clock Identity (Clock ID) of network devices is that each network device in the time synchronization network has its own Clock ID, which is used to uniquely mark each device in the network. A network device, such as an ATOM GPS optical module and a Building Integrated Timing Supply System (BITS for short) device, etc., all have their own Clock ID, but they cannot provide high-precision time sources. It is to receive the time source of GPS satellite or the time source of independent atomic clock, etc., and then transmit the time source to the downstream equipment. The newly added time source ID here is used to represent the real source of their time source.

[0071] That is to say, when the time source ID of the first network device is the same as the time source ID of the second network device, and the hop count of the time source of the first network device is the same as that of the time source of the second network device , the first network device does not switch the time source, that is, does not switch the time source currently used by itself from the first time source to the second time source from the second network device.

[0072] It should be understood that the more network elements the time source passes through the network, the greater the error will be introduced. Therefore, under the same circumstances, it is necessary to select a time source with a smaller value of Steps Removed. If the time source ID of the second time source is the same as the time source ID of the first time source, but the hop count is different, then the first network device can select the time source hop count between the first time source and the second time source A smaller time source, and switch the first time source of its own time source to the time source with the smallest number of hops.

[0073] It should also be understood that the second network device can be called an upstream device of the first network device, and the first network device can be called a downstream device of the second network device, and the upstream device can transmit its own time source to the downstream device, and the downstream device can receive The time source passed by the upstream device. Both the first network device and the second network device can include two ports, one of which is used to transmit its own time source to the downstream device to publish the synchronization time, and the other port can be used to receive the time of the upstream device or the time source device source to receive synchronized time.

[0074] Optionally, the time source information of the second network device may also include first indication information, where the first indication information is used to indicate that the time source information of the second time source of the first network device is different from the time of the first time source. When the source information is the same, it is forbidden to switch the time source of the first network device from the first time source to the second time source;

[0075] Wherein, in S220, if the time source information of the second time source is the same as the time source information of the first time source, the first network device is prohibited from switching the time source of the first network device from the first time source to the second time source , including: the first network device switches the time source of the first network device from the first time source to Secondary time source.

[0076]Specifically, the second network device may send first indication information to the first network device, where the first indication information is used to indicate that the time source information of the second time source of the first network device is different from the time source of the first time source. When the information is the same, the time source of the first network device is not switched from the first time source to the second time source, that is, the first indication information indicates that the time source does not switch back and is enabled. Further, the first indication information may be carried in the above-mentioned time source information of the second time source, after the first network device obtains the time source information of the second time source, it may obtain the time source information of the second time source Acquire the first indication information, and compare the time source information of the first time source with the time source information of the second time source according to the first indication information, and compare the time source information of the first time source with the second time source information When the time source information of the source is the same, the switching of the time source is not performed, that is, the time source currently used by the first network device is not switched from the first time source to the second time source, even if the priority of the second time source is higher.

[0077] It should be understood that a specific value can be set in the first indication information obtained by the first network device to indicate that the non-switchback mode is enabled, that is, it is used to indicate that the time source information of the first network device is in the second time source and the time source information of the first time source When the time source information is the same, time source switching will not be performed; other specific values ​​can also be set in the first indication information to indicate that the non-switchback mode is not enabled, that is, it is used to instruct the first network device to An optimal time source is determined from the first time source and the second time source, and the time source of the first network device is switched from the first time source to the optimal time source.

[0078] For example, it is assumed that the current time source of the second network device comes from the primary time source device or a device newly added to the network, and the time source of the first network device comes from the backup time source device. At this time, due to reasons such as the restoration of the main time source device from the fault state to the working state or the addition of new network devices, a new time source may be brought in for the first network device. At this time, the first network device needs to re-determine its own time source. time source. The first network device may obtain the time source information of the second time source used by the second network device, and obtain the following information from the time source information of the second time source: (1) the first indication information, and the first indication information Indicate that the time source does not switch back mode enable; (2) the time source ID of the second time source used by the second network device, and the time source ID of the second time source is the same as the time source ID of the first time source and the value is different is 0, indicating that the real time sources received by the two interfaces of the first network device are the same, that is, the time sources are consistent; (3) the hop count of the time source of the second time source, and the time source of the second time source The hop count of is the same as the value of the hop count of the time source of the first time source. At this time, the first network device determines whether the time source ID of the second time source is the same as its own time source ID and whether the time source hop count of the second time source is the same as that of its own time source according to the time source information of the second time source. Whether the number of hops is the same, the first network device, according to the indication of the first indication information, if both time source IDs and time source hops are the same, there is no need to perform source selection operations, even if the second time source comes from the main time source device (the priority of the second time source is higher than that of the first time source), and the first network device will not switch its current time source from the first time source to the second time source. That is to say, if the three conditions in (1) to (3) above are met at the same time, the source cutting action will not be performed.

[0079] Here, the time source ID of 0 can be used to indicate that the upstream device has not passed this parameter to the network device. For example, if the time source ID of the time source information obtained by the first network device from the second network device is 0, it means that the second network The device does not pass the time source ID of the second time source to the first network device. At this time, the first network device may determine the optimal time source among the first time source and the second time source according to the source selection algorithm, and switch the first time source of the first network device to the optimal time source.

[0080] Optionally, the above-mentioned first network device may include a boundary clock BC device, and the above-mentioned second network device may include a BC device or a time source device.

[0081] Wherein, the time source device may be, for example, a GPS satellite, a Beidou satellite, a Glonass satellite, a Galileo satellite or an independent atomic clock.

[0082] In S210, the first network device obtains the time source information of the second time source used by the second network device, specifically in two ways, which are combined below Figure 4 and Figure 5 The two modes proposed in the embodiments of the present invention are described in detail respectively.

[0083] way 1

[0084] A method for obtaining time source information of the second time source is: the first network device receives a Precision Time Protocol (Precision Time Protocol, "PTP") message sent by the second network device, and the reserved field of the PTP message Contains time source information of the second time source.

[0085] E.g image 3 The schematic diagram of the notification (Announce) message shown, the message includes a PTP message header and a PTP message content field, image 3 The shaded part in the middle is the message header, and the message content field is below the message header. The message content field in the Announce message at least includes:

[0086] The value of the OriginTime Stamp field is 0 or the estimated value of the Announce message sending time;

[0087] The current UTC offset value (Current UTC Offset) field carries the offset value between the current International Atomic Time (International Atomic Time, referred to as "TAI") and the Universal Time Coordinated (abbreviated as "UTC"), in seconds (s );

[0088] The Grandmaster Priority 1 field is the priority 1 attribute of the Grandmaster, which is used to compare priorities in the BMC algorithm. The smaller the value, the higher the priority, and the master time source refers to the upstream time The time source signal delivered by the source device;

[0089] The clock quality (Grandmaster Clock Quality) field of the master time source is the clock quality (Clock Quality) attribute of the master time source, including the level and precision of the master time source;

[0090] The field of Grandmaster Priority 2 (Grandmaster Priority 2) field is the priority 2 attribute of the master time source, which is used to compare priorities in the BMC algorithm, where the smaller the value, the higher the priority;

[0091] The main time source identification (Grandmaster Identity) field is the clock identification (Clock ID) attribute of the main time source;

[0092] The Steps Removed field indicates the number of hops between the local clock sending the Announce message and the advanced clock through the link;

[0093] The main time source source (Time Source) field indicates the source of the main time source, such as atomic clock, GPS, PTP, Network Time Protocol (Network Time Protocol, "NTP" for short), etc.;

[0094] The Reserved field is a reserved field.

[0095] It can be seen that there is a reserved field in the PTP message content, and the present invention can use this field to transmit time source information including the parameter value of the time source ID. For example, the setting and meaning of the value of the reserved field can be as follows :

[0096] (1) The default value is all 0, which means that the non-switchback mode is not enabled. At this time, you can select a high-priority time source according to the source selection algorithm and switch the current time source to a high-priority time source, so that the downstream equipment can be maintained compatible.

[0097] (2) Setting the value of the bit (bit) on the highest bit to 1 means that the non-switchback mode has been enabled, and means that if the time source ID and the number of time source hops are the same, source selection switching may not be performed;

[0098] (3) The value on the remaining 7 bits can represent the time source ID, and the only time source commonly used in the world (such as the time source from GPS satellites, the time source from Beidou satellites, etc.) needs to be assigned a fixed time source value to ensure interoperability , for example, the time source ID value of GPS can be specified as 1, the time source ID value of Beidou satellite is 2, and the value 3-31 can be reserved for subsequent use and must not be occupied;

[0099] The remaining 7 bits are all 0, which means that the information of the time source ID is not transmitted (that is, the upstream device does not transmit this parameter). At this time, even if the network device has enabled the non-switchback mode, the network device also performs normal source selection or switching.

[0100] (4) The value 32-127 can be planned and used according to the actual situation when deploying the time synchronization network, and can be manually configured. Network planning should avoid scenarios with the same time source ID value in the entire network, and you can refer to the use restrictions of Clock ID;

[0101] (5) Time-synchronized network devices need to support the ability to recognize the information in the reserved field;

[0102] (6) Time-synchronized network devices and time source devices need to be able to transmit the information in the reserved field to downstream devices, that is, to be able to transmit the time source information in the reserved field downstream through the Announce message.

[0103] way 2

[0104] Another way to obtain the time source information of the second time source is: the first network device receives the TLV field carried in the Announce packet sent by the second network device, and the TLV field includes the time source information of the second time source. That is to say, the second network device can transmit the time source information including the parameter value of the time source ID to the downstream device by attaching the TLV to the Announce message.

[0105] Type-Length-Value ("TLV" for short) is a data format. The length of the TLV field is required to be an even number of bytes. Its structure is as follows:

[0106]

[0107] Among them, tlvType indicates the type of TLV, indicating the meaning of the current data packet, such as indicating the type of a single package or the type of a nested package; lengthField indicates the byte length of the TLV field, which includes three parts: tlvType, lengthField and valueField ;valueField indicates the content body of the data in the TLV field, including the actual content of the data packet.

[0108] The TLV field can be attached at the end of the Announce message to transmit some additional information. Therefore, the newly added time source ID information can be encapsulated and transmitted by adding such a TLV field. The second network device may send the time source information of the second time source to the first network device through the TLV field.

[0109] Therefore, in the embodiment of the present invention, the network device compares its own current time source with the time source obtained from other network devices, and does not perform time source switching when the information of the two time sources is the same, thereby reducing unprofitable time sources. The time source switching action avoids unnecessary source switching events and alarm reporting, and reduces the maintenance cost of the live network.

[0110] It should be understood that in various embodiments of the present invention, the sequence numbers of the above-mentioned processes do not mean the order of execution, and the execution order of each process should be determined by its functions and internal logic, rather than by the embodiment of the present invention. The implementation process constitutes any limitation.

[0111] The following will combine Figure 4 to Figure 6 , to describe a network device according to an embodiment of the present invention, and the technical features described in the foregoing method embodiments may be applicable to the following device embodiments.

[0112] Figure 4 A network device 400 according to an embodiment of the present invention is shown. like Figure 4 As shown, the network device 400 is a first network device, and the network device 400 includes:

[0113] An obtaining unit 410, configured to obtain time source information of a second time source used by the second device;

[0114] A processing unit 420, configured to forbid the time source information of the second time source acquired by the acquiring unit 420 to The time source of the network device is switched from the first time source to the second time source from the first time source.

[0115] Therefore, the network device compares the current time source with the time source obtained from other network devices, and does not switch the time source when the information of the two time sources is the same, thereby avoiding the extra overhead caused by unnecessary time source switching.

[0116] Optionally, the time source information of the first time source includes a time source identification ID of the first time source and a hop count of the first time source, and the time source ID of the first time source is used to identify The first time source; the time source information of the second time source includes the time source ID of the second time source and the hop count of the second time source, and the time source ID of the second time source is used for identifying the second time source.

[0117] Optionally, the time source information of the second time source further includes first indication information, and the first indication information is used to indicate that the time source information of the second time source is the same as the time source information of the first network device. When the time source information of the first time source is the same, it is forbidden to switch the time source of the first network device from the first time source to the second time source;

[0118] Wherein, the processing unit 420 is specifically configured to: according to the first indication information, when the time source information of the second time source is the same as the time source information of the first time source, prohibit the The time source of the network device is switched from the first time source to the second time source.

[0119] Optionally, the acquiring unit 410 is specifically configured to: receive a Precision Time Protocol (PTP) message sent by the second network device, where a reserved field of the PTP message includes time source information of the second time source.

[0120] Optionally, the acquiring unit 420 is specifically configured to: receive an Announce message sent by the second network device, where the type-length-value TLV field carried in the Announce message includes the time source of the second time source Time source information.

[0121] Optionally, the first network device includes a boundary clock BC device, and the second network device includes a BC device or a time source device.

[0122] Optionally, the time source device includes a global positioning system GPS satellite, a Beidou satellite, a GLONASS satellite, a Galileo satellite or an independent atomic clock.

[0123] Optionally, the processing unit 420 is further configured to: when the information on the second time source is different from the information on the first time source, determine the best time source among the first time source and the second time source. an optimal time source, and switch the time source of the first network device from the first time source to the optimal time source.

[0124] It should be noted that in this embodiment of the present invention, the acquiring unit 410 and the processing unit 420 may be implemented by a processor. like Figure 5 As shown, the network device 500 may include a processor 510 , a transceiver 520 and a memory 530 . Wherein, the transceiver 520 may include a receiver 521 and a transmitter 522, and the memory 530 may be used to store time source information of a time source used by network devices or codes executed by the processor 510, and the like. Various components in the network device 500 can be coupled together through a bus system 540, wherein the bus system 540 includes a power bus, a control bus, and a status signal bus, etc. in addition to a data bus. Wherein, the network device 500 is the first network device, and the processor 510 is configured to:

[0125] Acquiring time source information of a second time source used by the second device;

[0126] When the time source information of the second time source is the same as the time source information of the first time source used by the first network device, prohibit switching the time source of the first network device from the first time source is the second time source.

[0127] Therefore, the network device compares the current time source with the time source obtained from other network devices, and does not switch the time source when the information of the two time sources is the same, thereby avoiding the extra overhead caused by unnecessary time source switching.

[0128] Optionally, the time source information of the first time source includes a time source identification ID of the first time source and a hop count of the first time source, and the time source ID of the first time source is used to identify The first time source; the time source information of the second time source includes the time source ID of the second time source and the hop count of the second time source, and the time source ID of the second time source is used for identifying the second time source.

[0129] Optionally, the time source information of the second time source further includes first indication information, and the first indication information is used to indicate that the time source information of the second time source is the same as the time source information of the first network device. When the time source information of the first time source is the same, it is forbidden to switch the time source of the first network device from the first time source to the second time source;

[0130] Wherein, the processor 510 is specifically configured to: according to the first indication information, when the time source information of the second time source is the same as the time source information of the first time source, prohibiting the The time source of the network device is switched from the first time source to the second time source.

[0131] Optionally, the receiver 521 is specifically configured to: receive a Precision Time Protocol PTP message sent by the second network device, where a reserved field of the PTP message includes time source information of the second time source.

[0132] Optionally, the receiver 521 is specifically configured to: receive an Announce message sent by the second network device, where the type-length-value TLV field carried in the Announce message includes the time source of the second time source Time source information.

[0133] Optionally, the first network device includes a boundary clock BC device, and the second network device includes a BC device or a time source device.

[0134] Optionally, the time source device includes a global positioning system GPS satellite, a Beidou satellite, a GLONASS satellite, a Galileo satellite or an independent atomic clock.

[0135] Optionally, the processor 510 is further configured to: when the information on the second time source is different from the information on the first time source, determine the best time source among the first time source and the second time source. an optimal time source, and switch the time source of the first network device from the first time source to the optimal time source.

[0136] Image 6 It is a schematic structure diagram of the system chip of the embodiment of the present invention. Image 6 The system chip 600 includes an input interface 601, an output interface 602, at least one processor 603, and a memory 604. The input interface 601, the output interface 602, the processor 603, and the memory 604 are connected through a bus 605. The processing The processor 603 is used to execute the code in the memory 604, when the code is executed, the processor 603 implements figure 2 and image 3 A method performed by a network device in . The bus 605 is only an example of the connection mode. In the embodiment of the present invention, the input interface 601, the output interface 602, the processor 603, and the memory 604 can also be connected in other ways, which are not limited here .

[0137] Figure 4 network device 400 as shown or Figure 5 network device 500 as shown or Image 6 The SoC 600 shown is capable of implementing the aforementioned figure 2 and image 3 In order to avoid repetition, the various processes implemented by the network device in the method embodiment will not be repeated here.

[0138] Those of ordinary skill in the art can realize that the units and algorithm steps of the examples described in conjunction with the embodiments disclosed herein can be implemented by electronic hardware, computer software, or a combination of the two. In order to clearly illustrate the relationship between hardware and software Interchangeability. In the above description, the composition and steps of each example have been generally described according to their functions. Whether these functions are executed by hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art may use different methods to implement the described functions for each specific application, but such implementation should not be regarded as exceeding the scope of the present invention.

[0139] Those skilled in the art can clearly understand that for the convenience and brevity of the description, the specific working process of the above-described system, device and unit can refer to the corresponding process in the foregoing method embodiment, and will not be repeated here.

[0140] In the several embodiments provided in this application, it should be understood that the disclosed systems, devices and methods may be implemented in other ways. For example, the device embodiments described above are only illustrative. For example, the division of the units is only a logical function division. In actual implementation, there may be other division methods. For example, multiple units or components can be combined or May be integrated into another system, or some features may be ignored, or not implemented. In addition, the mutual coupling or direct coupling or communication connection shown or discussed may be indirect coupling or communication connection through some interfaces, devices or units, and may also be electrical, mechanical or other forms of connection.

[0141] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place, or may be distributed to multiple network units. Part or all of the units can be selected according to actual needs to achieve the purpose of the solution of the embodiment of the present invention.

[0142] In addition, each functional unit in each embodiment of the present invention may be integrated into one processing unit, each unit may exist separately physically, or two or more units may be integrated into one unit. The above-mentioned integrated units can be implemented in the form of hardware or in the form of software functional units.

[0143] If the integrated unit is realized in the form of a software function unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention is essentially or the part that contributes to the prior art, or all or part of the technical solution can be embodied in the form of software products, and the computer software products are stored in a storage medium In, several instructions are included to make a computer device (which may be a personal computer, a server, or a network device, etc.) execute all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-OnlyMemory), random access memory (RAM, Random Access Memory), magnetic disk or optical disk and other media that can store program codes.

[0144]The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person familiar with the technical field can easily think of various equivalents within the technical scope disclosed in the present invention. Modifications or replacements shall all fall within the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.