CN102983960A - Method and device for implementing rapid synchronous switching in PTP (precision time protocol) - Google Patents
Method and device for implementing rapid synchronous switching in PTP (precision time protocol) Download PDFInfo
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- CN102983960A CN102983960A CN2012105178317A CN201210517831A CN102983960A CN 102983960 A CN102983960 A CN 102983960A CN 2012105178317 A CN2012105178317 A CN 2012105178317A CN 201210517831 A CN201210517831 A CN 201210517831A CN 102983960 A CN102983960 A CN 102983960A
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Abstract
The invention discloses a method and a device for implementing rapid synchronous switching in a PTP (precision time protocol). A plurality of clock examples are arranged on clock PTP equipment and a plurality of synchronous interfaces are configured, so that the synchronous interfaces are connected with main clocks and a clock synchronous information processing module, the clock synchronous information processing module receives the information of the main clocks through the synchronous interfaces, the synchronous relations between the plurality of main clocks and the clock examples are built, the best clock example is selected from all the clock examples through a clock output module to be output to be used as a current system, and if the synchronous relation of the selected clock example is changed, the clock output module is immediately switched to another clock example to be output. According to the method and the device for implementing rapid synchronous switching in the PTP, the synchronous convergence time of the clocks is improved, the clocks are rapidly synchronously switched, and the reliability of the PTP is improved.
Description
Technical field
The present invention relates to the network communications technology field, relate in particular to and realize method and the device that Fast synchronization switches among a kind of synchronous ethernet PTP.
Background technology
PTP (Precision Time Protocol, accurate clock synchronization protocol) is that it is compared with traditional Clock Synchronization Technology, and obvious advantage (as shown in Table 1) is arranged by the agreement of a kind of precise synchronization of IEEE1588 definition.What PTP adopted is two-way channel, and precision is the ns level, and expense is low, can adapt to different access environment etc.Under the current industry background that this constantly requires to improve to precision, PTP has become a kind of inexorable trend of development.
Table one
| ? | GPS | NTP | The Big Dipper | Atomic clock | IEEE1588V2 |
| Typical case's time service precision | 20ns | 10ms | 100ns | 10ns | 100ns |
| Need satellite to cover | Need | Do not need | Need | Do not need | Do not need |
| Locking time | 40s | 30ns | 60s | ? | 60ns |
| Integrated cost | In | Low | High | High | Low |
| Support ethernet port | Do not support | Support | Do not support | Do not support | Support |
| Controllability | Low | High | In | High | High |
| Fail safe | Low | Low | High | High | In |
| Reliability | In | High | In | High | High |
PTP is a kind of typical master-slave synchronisation system, in the synchronizing process of system, master clock cycle issue PTP time synchronization protocol and time information, receive the timestamp information that the master clock port is sent from clock port, system calculates principal and subordinate's wire time according to timestamp information and postpones and principal and subordinate's time difference, utilizes this time difference to adjust local zone time.And result's calculating of passing through repeatedly to adjust adopts the way of infinite approach to reach from frequency and the phase place of equipment and main equipment time consistency from the difference on the frequency between equipment and the main equipment.Although the mode that PTP has adopted hardware to add software improves the accuracy of time synchronized, yet the load mode based on message, the accuracy that it is synchronous and convergence time inevitably are subject to (the Packet Delay Variation of PDV in the message transmission procedure, the packet delay deviation) impact, in order to reduce PDV to the impact of accuracy, software can adopt complicated algorithm progressively to adjust from the deviation of clock and master clock, and this has increased undoubtedly from the synchronous convergence time of clock and the maintenance of main time.
Be illustrated in figure 7 as the synchronizing process of PTP, specific as follows: PTP equipment sends and accepts the Announce message, learns simultaneously each road signal clock quality information;
Device interior carries out BMC (Best Master Clock to the clock information that receives, best master clock) algorithm, therefrom choose optimum clock source as master clock, determine the state of synchro system middle port, the canonical algorithm regulation, equipment can only have at most one, and to carry out temporal information from clock port and the master clock Master that chooses mutual, and the timestamp information that simultaneously master clock Master is sent is by software skew computing time, and progressively adjust local clock until synchronously; Establishment is from the synchronized relation of clock and master clock.
Can find out from the synchronizing process of above-mentioned PTP, whole PTP synchronizing process need to consume the long period, in case and the master clock in the PTP link breaks down, just need again to select new master clock according to above-mentioned synchronizing process, and adjust the clock synchronous from clock, this switching process need expends the plenty of time, can't satisfy the professional demand of switching fast.
Therefore need a kind of technology that when master clock breaks down, can switch to fast another master clock.
Summary of the invention
The object of the invention is to overcome the defective of prior art, switch problem consuming time for synchronous ethernet PTP master clock, provide a kind of and can high efficiencyly in PTP, realize the synchronously method and apparatus of switching, mode by the multi-clock example, adopting Multi-path synchronous mechanism from clock, when one tunnel synchronizing signal is lost, switch to fast another road synchronizing signal, to improve the convergence time of clock synchronous.
For achieving the above object, the present invention proposes following technical scheme: realize among a kind of PTP comprising the method that Fast synchronization switches:
Disposing several sync caps from clock PTP device protocol face, make it connect several master clocks;
In clock PTP equipment, several clock examples are being set, and are setting up synchronized relation with described several master clocks;
Describedly receive the clock information of described master clock from clock PTP equipment by described sync cap, and adjust in real time the described clock example master clock clock synchronous corresponding with it;
Describedly from several clock examples, select optimum clock to export from clock PTP equipment, and when synchronized relation corresponding to the clock example of optimum changed, the clock example that switches to immediately suboptimum was exported.
Described clock example is based on the timekeeping system of hardware, is responsible for safeguarding the synchronized relation of local clock and master clock.
The clock example of described optimum is the parameter attribute according to the clock example, and manual configuration goes out optimum clock example output.
Described synchronized relation changes and comprises variation that the master clock synchronization link occurs and the variation of the caused synchronized relation of master clock faults itself.
When described synchronized relation generation political reform, the synchronized relation between described clock example and the described master clock will disconnect, and discharge described clock example, make it become idle clock example.
Described several master clocks for the output clock of described several upper level network equipments that join from clock PTP equipment.
The present invention also proposes the fast device of protection of a kind of PTP of realization, comprises being located in the clock PTP equipment:
Be disposed at several sync caps of agreement face, be used for being connected with several master clocks;
Several clock examples, be used for and described several master clocks between set up synchronized relation;
The clock synchronization information processing module be used for receiving the clock information of described master clock, and it is synchronous to adjust in real time the described clock example master clock phase clock corresponding with it;
The clock output module be used for selecting optimum clock to export from several clock examples, and when synchronized relation corresponding to the clock example of optimum broke down, the clock example that switches to immediately suboptimum was exported.
Described clock example is based on the timekeeping system of hardware, is responsible for safeguarding the synchronized relation of local clock and master clock.
Describedly also comprise several sync caps from clock PTP equipment, be used for receiving the clock information of described master clock and sending corresponding clock example to.
Described several master clocks for the output clock of described several upper level network equipments that join from clock PTP equipment.
Compared with prior art, realize the method and apparatus that Fast synchronization switches among the disclosed PTP, effectively shortened the convergence time of clock synchronous, and removed from because of master clock fault or clock chain circuit fault cause to re-start PTP synchronous, so that when one tunnel synchronizing signal is lost, can switch to fast another road synchronizing signal.
Description of drawings
Fig. 1 is the module diagram of realizing the Fast synchronization switching device shifter among the PTP of the present invention;
Fig. 2 is the flow chart of realizing the Fast synchronization changing method among the PTP of the present invention;
Fig. 3 is the flow chart of clock example of the present invention and master clock synchronizing process;
Fig. 4 is the flow chart that clock output module of the present invention is selected clock example output procedure;
Fig. 5 is the flow chart that master clock of the present invention is lost rear release clock example procedure;
Fig. 6 (a) schematic diagram that to be master clock break down with synchronization link from clock PTP equipment room;
Fig. 6 (b) is the schematic diagram of clock equipment faults itself;
Fig. 7 is the flow chart of existing clock synchronization compliant with precision time protocol synchronizing process.
Embodiment
Below in conjunction with accompanying drawing of the present invention, the technical scheme of the embodiment of the invention is carried out clear, complete description.
Only having a synchronised clock in the network of having used the PTP agreement is master clock, provides clock information in order to give the PTP network, and all devices in this network all keeps synchronously with this clock.Among the present invention, the equipment from clock synchronous with this master clock maintenance is called the equipment from clock PTP, describedly be connected with a plurality of upper level network equipments respectively by a plurality of sync caps from clock PTP equipment, described each upper level network equipment has respectively output clock, these output clocks all can be used as the clock source of PTP equipment, and keep synchronized relation from clock PTP equipment.
As shown in Figure 1, should from clock PTP equipment, be provided with the clock synchronization information processing module, a plurality of clock examples, and clock output module.Described clock synchronization information processing module also comprises several sync caps, the master clock of the upper level network equipment is by carrying out the clock information exchange between described sync cap and described clock synchronization information processing module, described several clock examples are by several sync caps, under the control of described clock synchronization information processing module, receive the synchronised clock information of the clock source of described correspondence, and by the clock output module clock example of optimum is exported.
Described master clock be described several master clocks for the output clock of described several upper level network equipments that join from clock PTP equipment, these master clocks can be regarded as from the clock source of clock PTP equipment.The corresponding master clock of clock example of described optimum is that the master clock of PTP equipment will be exported, and all the other master clocks are alternative master clock.When synchronized relation corresponding to optimum clock example broke down, all the other master clocks just can be selected as master clock, so all master clocks all can be used as the master clock of PTP equipment in the present embodiment.
Described clock synchronization information processing module is for the synchronized relation of controlling by a plurality of sync caps between a plurality of master clocks and a plurality of clock example, the i.e. synchronizing information that sends by receiving master clock of this clock synchronization information processing module, set up the synchronized relation with the clock example, and this synchronizing information is sent to the clock example corresponding with master clock, adjust in real time the clock of described clock example, make the clock synchronised of itself and corresponding master clock.
Described clock example is based on the timekeeping system of hardware, and the clock that is used for safeguarding the local clock example concerns with the clock synchronous of corresponding master clock; According to the hardware supports condition, can support the clock example of a plurality of and different master clock synchronised to move simultaneously.
Described clock output module is used for selecting the clock of current optimum to export to system from a plurality of clock examples, with the clock source as whole network, and when optimum clock example synchronized relation breaks down, selects immediately the second excellent clock example output.In addition, described clock output module also is responsible for receiving the control command of agreement face.
Described clock output module is clock accuracy at the parameter value of choosing the reference of output clock example time institute, controllability, the aspect information such as stability.
Described sync cap is used for connecting the master clock of clock synchronization information processing module and the upper level network equipment, and Real-Time Monitoring master clock state also receives the clock information that master clock sends, and adjusts alternately and synchronously to carry out clock information.
As shown in Figure 2, realize the method that Fast synchronization switches among the disclosed PTP, it is by introducing a plurality of clock examples from clock PTP equipment, so that keep simultaneously synchronized relation with a plurality of master clocks from clock PTP equipment, and from a plurality of clock examples, select optimum clock example and export, as the synchronised clock of PTP network.Simultaneously, when the clock example synchronized relation of the current optimum of choosing breaks down, switch to fast the clock example of another suboptimum from clock, specifically may further comprise the steps:
S1 is disposing several sync caps from clock PTP device protocol face, makes it connect respectively several different master clocks;
S2 is arranging several clock examples from clock PTP device interior, by the clock synchronization information processing module in clock PTP equipment, sets up the synchronized relation of described each clock example and master clock;
S3 after described clock synchronization information processing module receives the clock information of each master clock by described sync cap, then adjusts the clock value of the clock example corresponding with each master clock, and is synchronous with own corresponding master clock to guarantee;
S4, the clock output module is according to the parameter value of each clock example, manual configuration goes out optimum clock example and output, if the corresponding master clock of clock example of choosing breaks down, described clock output module is selected the second excellent clock example output by same method immediately from other clock examples.
Wherein, be illustrated in figure 3 as the process of setting up of clock example and master clock synchronized relation, specifically comprise: the sync cap of static configuration PTP equipment (from port) at first, detect in real time the master clock state that sync cap connects, judge whether to find master clock information, if do not find, then continue to detect, in case find master clock information, whether available free described clock synchronization information processing module detect clock example, if the present clock example is all processed connection status, then ignore this master clock, whole process finishes; If current have the clock example to be in idle condition, then choose this clock example, PTP is synchronous in beginning, and the quality information of this clock example then is set, and sends the information that the clock example upgrades, and finishes whole process.
Described clock output module is selected the output procedure of optimum clock example, as shown in Figure 4, comprise clock output module real-time listening clock example updating message, judge whether to exist and upgrade, just continue if not to monitor, if renewal is arranged, the quality information that then compares each clock example, select optimum clock example, if the current clock example that optimum has been arranged judges then whether the new clock example of selecting equals the present clock example, if it is process finishes, if be not equal to, the clock example that then will newly select is arranged to the optimum clock example that the clock output module is selected, terminal procedure.
When detecting synchronized relation from clock PTP device synchronization interface and occur to lose such as master clock, described clock synchronization information processing module disconnects the synchronized relation of this master clock and corresponding clock example, discharge the clock example, make it become idle clock example, and refresh clock example information, the clock output module can be done synchronous renewal to the selection of optimum clock example after detecting clock example information after the renewal.
Be illustrated in figure 5 as take master clock and lose as the process that is released to of example explanation clock example, comprise: described sync cap detects master clock when losing, search the corresponding clock example of this master clock by the clock synchronization information processing module, judge whether this clock example is the clock example that output is chosen, if not, the synchronized relation of the master clock that just directly disconnects this clock example and lose discharges this clock example; The optimum clock example of if it is choosing, and disconnect first the synchronized relation of this clock example and master clock, discharge the clock example, send simultaneously clock example lastest imformation, last terminal procedure.
Such as Fig. 6 (a), shown in 6 (b), the variation that the clock example among the present invention and the synchronized relation between master clock occur comprises master clock and variations such as fault from clock PTP equipment room synchronization link, causes master clock to be lost and the protection carried out; And the fault of clock equipment self, the variation such as cause that master clock is lost and the protection carried out.
When normally moving from clock PTP equipment, only having a master clock in several master clocks that sync cap connects is really to export from PTP equipment by the clock example, and remaining master clock is only synchronous with corresponding clock example.In case the master clock as output breaks down, PTP equipment will select another synchronous master clock to export, and the system of being provides clock information.
Please again referring to Fig. 1, realize among the PTP that discloses in the preferred embodiment of the present invention from clock PTP equipment (PTP synchronization module), disposing three sync cap A of clock synchronization information processing module, B in the Fast synchronization switching device shifter, C, its respectively from the master clock A of different higher level's network equipment, master clock B, master clock C is corresponding, and in clock PTP equipment, be provided with simultaneously three clock examples, be respectively clock example A, clock example B, clock example C.
Specifically, master clock A, master clock B, master clock C is simultaneously to sync cap A, B, C sends master clock information, and described master clock information exchange is crossed sync cap A, B, C reaches in the described clock synchronization information processing module, and at this moment, described clock synchronization information processing module is set up master clock A, B, C and clock example A, B, the synchronized relation of C, and according to the master clock information that receives, control the corresponding clock example of each master clock, adjust each clock example and corresponding master clock clock synchronous, so that clock example A and master clock A clock synchronous, clock example B and master clock B clock synchronous, clock example C and master clock C clock synchronous.
The clock output module is from clock example A subsequently, and clock example B selects the clock example output of a current optimum, as the clock information that offers system among the clock example C; If that master clock that optimum clock example is corresponding goes out active, then the clock output module is selected immediately the second excellent clock example and is switched output.
Wherein, optimum clock can be specified by manual configuration is static, also can pass through the election of BMC (Best MasterClock, best master clock) protocol dynamic.
The synchronizing process of described clock example and described master clock is existing PTP synchronizing process.
The present invention is by several clock examples whiles and several master clock clock synchronous, this is just so that one group of clock synchronous when breaking down, PTP equipment can switch on another group clock synchronous immediately, this has just saved the time that master clock consumes that reselects, and has greatly improved the convergence time of synchronised clock.
Technology contents of the present invention and technical characterictic have disclosed as above; yet those of ordinary skill in the art still may be based on teaching of the present invention and announcements and are done all replacement and modifications that does not deviate from spirit of the present invention; therefore; protection range of the present invention should be not limited to the content that embodiment discloses; and should comprise various do not deviate from replacement of the present invention and modifications, and contained by the present patent application claim.
Claims (10)
1. realize the method that Fast synchronization switches among a PTP, it is characterized in that comprising:
Disposing several sync caps from clock PTP device protocol face, make it connect several master clocks;
In clock PTP equipment, several clock examples are being set, and are setting up synchronized relation with described several master clocks;
Describedly receive the clock information of described master clock from clock PTP equipment by described sync cap, and adjust in real time the described clock example master clock clock synchronous corresponding with it;
Describedly from several clock examples, select optimum clock to export from clock PTP equipment, and when synchronized relation corresponding to the clock example of optimum changed, the clock example that switches to immediately suboptimum was exported.
2. the method described in according to claim 1, it is characterized in that: described clock example is based on the timekeeping system of hardware, is used for safeguarding the clock of clock example and the synchronized relation of master clock.
3. the method described in according to claim 1 is characterized in that: the clock example of described optimum is that parameter attribute according to the clock example carries out manual configuration or according to automatically configuration of agreement.
4. the method described in according to claim 1 is characterized in that: described synchronized relation changes and comprises variation that the master clock synchronization link occurs and the variation of the caused synchronized relation of master clock faults itself.
5. the method described in according to claim 4, it is characterized in that: when described synchronized relation generation political reform, the synchronized relation between described clock example and the described master clock will disconnect, and discharge described clock example, make it become idle clock example.
6. the method described in according to claim 1 is characterized in that: described several master clocks for the output clock of described several upper level network equipments that join from clock PTP equipment.
7. realize the device that Fast synchronization switches among the PTP, it is characterized in that comprising and be located in the clock PTP equipment:
Be disposed at several sync caps of agreement face, be used for being connected with several master clocks;
Several clock examples, be used for and described several master clocks between set up synchronized relation;
The clock synchronization information processing module be used for receiving the clock information of described master clock, and it is synchronous to adjust in real time the described clock example master clock phase clock corresponding with it;
The clock output module be used for selecting optimum clock to export from several clock examples, and when synchronized relation corresponding to the clock example of optimum broke down, the clock example that switches to immediately suboptimum was exported.
8. device according to claim 7, it is characterized in that: described clock example is based on the timekeeping system of hardware, is responsible for safeguarding the synchronized relation of local clock and master clock.
9. device according to claim 7 is characterized in that: describedly also comprise several sync caps from clock PTP equipment, be used for receiving the clock information of described master clock and sending corresponding clock example to.
10. the device described in according to claim 7 is characterized in that: described several master clocks for the output clock of described several upper level network equipments that join from clock PTP equipment.
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| WO2014161213A1 (en) * | 2013-04-03 | 2014-10-09 | 北京东土科技股份有限公司 | Clock synchronization method and apparatus in seamless redundant network |
| CN104393976A (en) * | 2014-11-07 | 2015-03-04 | 北京华为数字技术有限公司 | Switching method and switching device |
| JP2021044777A (en) * | 2019-09-13 | 2021-03-18 | 株式会社東芝 | Ptp message selection method and program as well as ptp slave device |
| WO2021203725A1 (en) * | 2020-04-10 | 2021-10-14 | 兖矿集团有限公司 | Time synchronization method and system |
| CN115102658A (en) * | 2022-07-19 | 2022-09-23 | 中铁工程装备集团有限公司 | Clock synchronization method and system |
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| WO2014161213A1 (en) * | 2013-04-03 | 2014-10-09 | 北京东土科技股份有限公司 | Clock synchronization method and apparatus in seamless redundant network |
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| JP2021044777A (en) * | 2019-09-13 | 2021-03-18 | 株式会社東芝 | Ptp message selection method and program as well as ptp slave device |
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Application publication date: 20130320 |