CN102938676A

CN102938676A - Method, device and system for processing time synchronization

Info

Publication number: CN102938676A
Application number: CN2011102347501A
Authority: CN
Inventors: 齐国民
Original assignee: ZTE Corp
Current assignee: ZTE Corp
Priority date: 2011-08-16
Filing date: 2011-08-16
Publication date: 2013-02-20
Anticipated expiration: 2031-08-16
Also published as: CN102938676B

Abstract

The invention discloses a method, a device and a system for processing time synchronization. The method comprises the following steps of adopting a timestamp information message which is received by one of a main clock and a slave clock through a receiving port and used for the time synchronization and recording and receiving the time of the information message; recording the sending time of the timestamp information message through a sending port, wherein the sending port and the receiving port are synchronous with a device where the sending port and the receiving port are arranged in time; revising time information carried in the timestamp information message and used for the time synchronization according to the receiving time and the sending time of the timestamp information message; and sending the timestamp information message to the other one of the main clock and the slave clock through the sending port. By means of the method, the device and the system for processing the time synchronization, the problem that a time synchronization method is complicated and corresponding network design is complicated and high in cost in the prior art of passive optical networks is solved, the method for processing the time synchronization is simple in process, and a corresponding network device is simple and low in cost.

Description

Time synchronizing method, Apparatus and system

Technical field

The present invention relates to the communications field, in particular to time synchronizing method, Apparatus and system.

Background technology

EPON (Passive Optical Network, referred to as PON) (for example, EPON/10GEPON, GPON/XGPON etc.) be a kind of new broadband optical access technology, Fig. 1 is the structured flowchart according to the EPON of prior art, as shown in Figure 1, EPON comprises: optical line terminal (Optical Line Terminal, referred to as OLT), light routing network (Optical Distributable Network, referred to as ODN), a plurality of optical network units (Optical NetworkUnit, referred to as ONU) or Optical Network Terminal (Optical Network Terminal is referred to as ONT).

PTP IEEE1588, it is a kind of packet-based time synchronization protocol, its basic thought is the cooperation by software and hardware, the time of sending and the time of reception of record synchronised clock information, and each bar information of giving adds corresponding timestamp, by calculating, the recipient just can calculate own clocking error (being time delay) in network, thereby realizes on the network from the time synchronized between equipment clock and the master clock.

IEEE1588 has had IEEE1588V1 and two versions of IEEE1588V2, Fig. 2 is the principle schematic according to IEEE1588 of the prior art, as shown in Figure 2, the hypothesis of IEEE1588 characteristic symmetry Network Based adopts master-slave mode, timed sending time message, the recipient calculates skew and circuit delay between the master-salve clock according to time message, thereby this locality is proofreaied and correct synchronously from clock, and its packet-based mode can make that each network element reaches synchronous on the network.

In Fig. 2, master clock sends synchronously (sync) message, and the record tranmitting data register is t1 constantly, it is t2 that sync message arrives from clock time, then master clock sends and follows (follow up) message, this follows message and carries the temporal information t1 that master clock sends sync message, then from clock forward delay interval request delay_req information, and the tranmitting data register that records this message code is t3 constantly, it is t4 constantly that delay_req message arrives master clock, afterwards master clock loopback time-delay response message delay resp, this message is carried the temporal information t4 that delay_req message reaches master clock.

Suppose that message is from master clock to being Δ T from the time-delay of clockwise path _Ms, message is from time-delay is Δ T from master clock to master clock direction path _Sm, the initial deviation of master-salve clock is T _Offset, thus, can obtain following relationship:

T2=t1+T _Offset+ Δ T _MsFormula (1)

T4=t3-T _Offset+ Δ T _SmFormula (2)

T _Offset=[(t2-t4)-(t1-t3)-(Δ T _Ms-Δ T _Sm)]/2 formula (3)

If network is symmetrical, i.e. Δ T _Ms=Δ T _Sm, so:

T _Offset=[(t2-t4)-(t1-t3)]/2 formula (4)

Δ T _Ms=Δ T _Sm=[(t2+t4)-(t1+t3)]/2 formula (5)

Just can adjust in real time local from clock, so that it reaches synchronous with master clock according to above result of calculation.

Fig. 3 is the schematic diagram of the forwarding of IEEE1588 time-stamping messages message of the prior art under the DBA scheduling, as shown in Figure 3, the direct transparent transmission of the IEEE1588 message of Ethernet on the PON network transmitted, can be found out by the analysis to Fig. 2, if network bi-directional time-delay is fixing, change greatlyr, shake is greatly, then can cause the deviation of result of calculation larger, thereby synchronous accuracy reduce.Because PON itself, the uplink message delay variation that its up DBA scheduling causes is larger, cause link bidirectional time delay error larger, thereby shake is also large.At traditional IEEE1588 message through each networking node device the time, the capital is because network congestion, various QOS algorithm and message processing, message is unfixing in the time delay of device interior storage forwarding, thereby jitter and wander is larger, cause by Fig. 2 algorithm calculate to obtain between the master-salve clock deviation or the path delay of time jitter and wander excessive, thereby finally understand the synchronous accuracy of influence time.

Therefore, as the above analysis, exist shake to have influence on greatly the problem of the accuracy of time synchronized thereby in the PON network, carry out time synchronized at present.

Summary of the invention

Main purpose of the present invention is to provide a kind of time synchronizing method, Apparatus and system, to address the above problem.

According to an aspect of the present invention, a kind of time synchronizing method is provided, comprise the steps: to receive time-stamping messages message for time synchronized by the receiving port in the EPON from master clock and the side from clock, and record receives the time of described time-stamping messages message; Record sends time of described time-stamping messages message by the transmit port in the EPON, and wherein, the equipment time at described transmit port and described receiving port and place keeps synchronously; According to the time of the time that receives described time-stamping messages message and the described time-stamping messages message of transmission, the temporal information that is used for time synchronized of carrying in the described time-stamping messages message is revised; Send described time-stamping messages message by described transmit port to described master clock and the opposing party from clock.

Preferably, record time of receiving described time-stamping messages message comprises: record the time that described time-stamping messages message arrives described receiving port; The time that arrives described receiving port is compensated according to the first make-up time and/or the second make-up time, wherein, described the first make-up time is that described time-stamping messages message arrives described receiving port and arrives time-delay between the corresponding physical port of described receiving port, and described the second make-up time is the processing time that receives described time-stamping messages message process; The time that will obtain after will compensating the time that described time-stamping messages message arrives described receiving port, be recorded as the time that receives described time-stamping messages message.

Preferably, record comprised by the time that described transmit port sends described time-stamping messages message: record the time that described time-stamping messages message arrives described transmit port; The time that arrives described transmit port is compensated according to the 3rd make-up time and/or the 4th make-up time, wherein, described the 3rd make-up time is the error that described time-stamping messages message arrives time and the actual time that sends of described transmit port, and described the 4th make-up time is for to the described processing time of revising for the temporal information of time synchronized; The time that will obtain after will compensating the time that described time-stamping messages message arrives described transmit port, be recorded as the time that sends described time-stamping messages message by described transmit port.

Preferably, the time of the equipment at described transmit port and described receiving port and place keeps one of at least synchronously in the following manner: the telecommunication standards group ITU-T of International Telecommunications Union G.984.3AD2, the telecommunication standards group ITU-T of International Telecommunications Union G.987.3, IEEE802.1as.

Preferably, record the time that receives the time of described time-stamping messages message and send described time-stamping messages message by described transmit port by following time format: described time format comprises: be used to indicate the field on date, the field that is used to indicate hour field of minute second and is used to indicate nanosecond.

Preferably, will receive the time of described time-stamping messages message and be recorded in the described time-stamping messages message by the time that described transmit port sends described time-stamping messages message by described receiving port.

According to a further aspect in the invention, a kind of time synchronizing device is provided, comprise: very first time stamp message sink module, the receiving port that is used for by EPON receives time-stamping messages message for time synchronized from master clock and the side from clock, and record receives the time of described time-stamping messages message; The second time-stamping messages receiver module, be used for receiving the described time-stamping messages message from described very first time stamp message sink module, and record sends the time of described time-stamping messages message by the transmit port in the EPON, wherein, the equipment time at described transmit port and described receiving port and place keeps synchronously; Correcting module is used for the time according to the time that receives described timestamp message and the described time-stamping messages message of transmission, and the temporal information that is used for time synchronized of carrying in the described time-stamping messages message is revised; The time-stamping messages sending module is used for sending described time-stamping messages message by described transmit port to described master clock with from the opposing party of clock.

Preferably, described very first time stamp message sink module comprises: the first record cell is used for recording the time that described time-stamping messages message arrives described receiving port; The first compensating unit, be used for according to the first make-up time and/or the second make-up time the time that arrives described receiving port being compensated, wherein, described the first make-up time is that described time-stamping messages message arrives described receiving port and arrives time-delay between the corresponding physical port of described receiving port, and described the second make-up time is the processing time that receives described time-stamping messages message process; The second record cell, is recorded as the time that receives described time-stamping messages message at the time that obtains after being used for compensating the time that described time-stamping messages message arrives described receiving port.

Preferably, described the second time-stamping messages receiver module comprises: the 3rd record cell is used for recording the time that described time-stamping messages message arrives described transmit port; The second compensating unit, be used for according to the 3rd make-up time and/or the 4th make-up time the time that arrives described transmit port being compensated, wherein, described the 3rd make-up time is the error that described time-stamping messages message arrives time and the actual time that sends of described transmit port, and described the 4th make-up time is for to the described processing time of revising for the temporal information of time synchronized; The 4th record cell, is recorded as the time that sends described time-stamping messages message by described transmit port at the time that obtains after being used for compensating the time that described time-stamping messages message arrives described transmit port.

In accordance with a further aspect of the present invention, a kind of time synchronizing system is provided, comprise: clock equipment, from clockwork, optical line terminal OLT, optical network unit ONU, also comprise: above-mentioned device, wherein, described device is connected to described clock equipment and described between clockwork, and described clock equipment, described pass between clockwork, described OLT and described ONU are one of following: described clock equipment and describedly be independent of respectively described OLT and described ONU from clockwork; Described clock equipment is positioned on the described OLT, describedly is independent of described OLT and described ONU from clockwork; Described clock equipment is independent of described OLT and described ONU, describedly is positioned on the described ONU from clockwork; Described clock equipment is positioned on the described OLT, describedly is positioned on the described ONU from clockwork.

By the present invention, adopt by the receiving port in the EPON and receive time-stamping messages message for time synchronized from master clock and the side from clock, and record receives the time of described time-stamping messages message; Record sends time of described time-stamping messages message by the transmit port in the EPON, and wherein, the equipment time at described transmit port and described receiving port and place keeps synchronously; According to the time of the time that receives described time-stamping messages message and the described time-stamping messages message of transmission, the temporal information that is used for time synchronized of carrying in the described time-stamping messages message is revised; Send described time-stamping messages message by described transmit port to described master clock and the opposing party from clock, in the PON network, carry out the problem that time synchronized existence shake has influence on greatly the accuracy of time synchronized thereby solved, between the loaded down with trivial details degree that improves time synchronized accuracy and attenuating handling process, obtained equilibrium.

Description of drawings

Accompanying drawing described herein is used to provide a further understanding of the present invention, consists of the application's a part, and illustrative examples of the present invention and explanation thereof are used for explaining the present invention, do not consist of improper restriction of the present invention.In the accompanying drawings:

Fig. 1 is the structured flowchart according to the EPON of prior art;

Fig. 2 is the principle schematic according to IEEE1588 of the prior art;

Fig. 3 is the schematic diagram according to the forwarding of IEEE1588 time-stamping messages message under the DBA scheduling of prior art;

Fig. 4 is the principle schematic according to the IEEE1588 transparent clock of prior art;

Fig. 5 is the flow chart according to the method for synchronizing time of the embodiment of the invention;

Fig. 6 is the structured flowchart according to the time synchronizing device of the embodiment of the invention;

Fig. 7 is the structured flowchart of very first time stamp message sink module in the time synchronism apparatus according to the preferred embodiment of the invention;

Fig. 8 is the structured flowchart of the second time-stamping messages receiver module in the time synchronism apparatus according to the preferred embodiment of the invention;

Fig. 9 is the schematic diagram of timestamp form according to the preferred embodiment of the invention;

Figure 10 is time synchronized computational methods system architecture diagram according to the preferred embodiment of the invention;

Figure 11 be the preferred embodiment according to the present invention lock in time method flow chart;

Figure 12 is the structured flowchart of passive optical network equipment according to the preferred embodiment of the invention;

Figure 13 is the flow chart of passive optical network equipment method for synchronizing time according to the preferred embodiment of the invention;

Figure 14 is the schematic diagram according to the network system of the preferred embodiment of the present invention one;

Figure 15 is the schematic diagram according to the network system of the preferred embodiment of the present invention two;

Figure 16 is the schematic diagram according to the network system of the preferred embodiment of the present invention three;

Figure 17 is the schematic diagram according to the network system of the preferred embodiment of the present invention four;

Figure 18 is the flow chart of implementing according to the optical line terminal one of the embodiment of the invention;

Figure 19 is the flow chart of implementing according to the optical line terminal two of the embodiment of the invention;

Figure 20 is the flow chart of implementing according to the optical network unit one of the embodiment of the invention;

Figure 21 is the flow chart of implementing according to the optical network unit two of the embodiment of the invention.

Embodiment

Hereinafter also describe in conjunction with the embodiments the present invention in detail with reference to accompanying drawing.Need to prove that in the situation of not conflicting, embodiment and the feature among the embodiment among the application can make up mutually.

In IEEE1588V2, introduced the concept of transparent clock TC, Fig. 4 is the principle schematic according to the IEEE1588 transparent clock of prior art, as shown in Figure 4, this transparent clock is a kind of end to end solution, by entry time and the outlet time of accurate record IEEE1588 message each node device on network, just can obtain time message through the residence time of all meshed network equipment, time message obtains by message intercommunication through the time delay at each networking in addition, just can make from clock acquisition and master clock synchronous finally by crossing the algorithm correction.

But, transparent clock in IEEE1588V2 all needs to calculate entry time and outlet time for each independent network node, calculate and the equal more complicated of flow process, for EPON, carry out synchronously in order to use this IEEE1588 agreement, all be that EPON is carried out segment processing, be synchronous between master clock and the OLT, then synchronous between OLT and the ONU, last ONU and between the clock synchronously, especially between master clock and the OLT synchronously and between clock and the ONU synchronously, need relevant software and hardware to solve, OLT and ONU must have the intercommunication of similar IEEE1588 time protocol massages and processing capacity, and the software and hardware design is complicated, has improved cost.

In following examples, EPON integral body is used as a transparent clock, calculate time-stamping messages message (or being called time-stamping messages, timestamp message) at the residence time of EPON, thereby revise this time-stamping messages message, so that master-salve clock synchronization.Fig. 5 is the flow chart according to the method for synchronizing time of the embodiment of the invention, and as shown in Figure 5, the method comprises the steps:

Step S502 receive time-stamping messages message for time synchronized by the receiving port in the EPON from master clock and the side from clock, and record receives the time of this time-stamping messages message;

Step S504, record sends the time of this time-stamping messages message by the transmit port in the EPON, wherein, the equipment time at this transmit port and this receiving port and place keeps synchronously, synchronous mode can be a lot, for example, International Telecommunications Union's telecommunication standards group ITU-T G.984.3AD2, the telecommunication standards group ITU-T G..987.3 of International Telecommunications Union, IEEE802.1as etc.;

Step S506 according to the time of the time that receives this time-stamping messages message and this time-stamping messages message of transmission, revises the temporal information that is used for time synchronized of carrying in this time-stamping messages message;

Step S508 sends this time-stamping messages message by this transmit port to this master clock and the opposing party from clock.

Pass through above-mentioned steps, be recorded in respectively the time of receiving port time of reception stamp message packet and the time of stabbing message packet in the transmit port transmitting time, and at the timestamp message of this transmit port transmission according to above-mentioned time correction, thereby realize the synchronous of master-salve clock.This implementation method no matter uplink message or downlink message all can directly directly be revised the temporal information that is used for time synchronized in the timestamp message, make temporal information in the timestamp message directly embody transmission and processing delay at the PON network, no longer need to consider the asymmetric problem of up-downgoing time delay, thereby reduced in terms of existing technologies shake and improved accuracy, and, above-mentioned steps is processed simple, no longer need master clock, OLT, ONU and carry out progressively synchronous from clock, operating process is simple, cost is lower, has obtained equilibrium between the loaded down with trivial details degree that improves time synchronized accuracy and attenuating handling process.

When implementing, more accurate in order to make by the time that receives of receiving port record, consider that these processing such as temporal information that receive in message, the revision message also need the time, from physical port be transferred to receiving port and message arrive transmit port and actual send between also have time delay, therefore, two kinds of more excellent compensation ways also are provided in the present embodiment, for this dual mode, can only use wherein a kind of, also can two kinds use simultaneously.If for some system, if these processing times or time-delay can neglect, also can not use these two kinds of processing modes, the below describes this dual mode.

Mode one, at first the logging timestamp message packet arrives the time of receiving port; Then according to the first make-up time and/or the second make-up time the time that arrives receiving port is compensated, wherein, this first make-up time is that the time-stamping messages message arrives the time-delay between receiving port and the corresponding physical port of arrival receiving port, and this second make-up time is the processing time of carrying out time of reception stamp message packet process; The time that will obtain after will compensating the time of time-stamping messages message arrival receiving port, be recorded as the time that receives the time-stamping messages message.Above-mentioned compensation process to the time, concrete condition in the time of can be according to implementation is selected, for example, when the time-delay between receiving port and the corresponding physical port of this receiving port is negligible than the processing time of receiving course, just can directly consider the latter, on the contrary, if the processing time of receiving course just can only be considered the time-delay between this receiving port and the corresponding physical port in the time of negligible with respect to the time-delay between receiving port and the corresponding physical port of this receiving port.

Mode two also can adopt such processing mode when recording the time of stabbing message packet by the transmit port transmitting time, that is, at first the logging timestamp message packet arrives the time of transmit port; The time that arrives transmit port is compensated according to the 3rd make-up time and/or the 4th make-up time, wherein, the 3rd make-up time arrived the time of transmit port and the error of the actual time that sends for this time-stamping messages message, the processing time of the 4th make-up time for the temporal information that is used for time synchronized is revised; The time that will obtain after will compensating the time of this time-stamping messages message arrival transmit port, be recorded as the time by transmit port transmitting time stamp message packet.

When implementing, record for the time, if receiving port and transmit port be not on an equipment, need so the time is recorded on receiving port place equipment and the equal storage device that can access of transmit port place equipment, certainly as an easier mode, can directly add in the corresponding time-stamping messages message time of record and forwarding.Such processing mode realizes easier.

When implementing, as a kind of more excellent execution mode, record is received time format corresponding to time of time-stamping messages message and the time format by transmit port transmitting time stamp message packet adopts a kind of new recording mode, for example, this time format comprises: be used to indicate the field on date, the field that is used to indicate hour field of minute second and is used to indicate nanosecond.Perhaps adopt similar IEEE1588 timestamp format mode writing time: be used to indicate second field and the field that is used to indicate nanosecond, these two kinds of forms realize than being easier to that all concrete form is realized with reference to shown in Figure 9.

A kind of time synchronizing device also is provided in the present embodiment, Fig. 6 is the structured flowchart according to the time synchronizing device of the embodiment of the invention, as shown in Figure 6, this device comprises very first time stamp message sink module 62, the second time-stamping messages receiver module 64, correcting module 66 and time-stamping messages sending module 68, and the below describes this device.

Very first time stamp message sink module 62, be used for receiving time-stamping messages message for time synchronized by receiving port from master clock with from a side of clock, and record time corresponding to this time-stamping messages message that receives, revise this timestamp message and forwarding according to time format of the present invention;

The second time-stamping messages receiver module 64, be connected to very first time stamp message sink module 62, be used for receiving the correspondent time message packet that sends from above-mentioned very first time stamp message sink module, and record is by the time of transmit port transmitting time stamp message packet, wherein, the equipment time at transmit port and receiving port and place keeps synchronously;

Correcting module 66, be connected to very first time stamp message sink module 62 and the second time-stamping messages receiver module 64, be used for the time according to the time that receives this timestamp message and this time-stamping messages message of transmission, the temporal information that is used for time synchronized of carrying in this time-stamping messages message is revised;

Time-stamping messages sending module 68 is connected to correcting module 66, is used for sending this time-stamping messages message by transmit port to master clock with from the opposing party of clock.

Fig. 7 is the structured flowchart of very first time stamp message sink module in the time synchronism apparatus according to the preferred embodiment of the invention, as shown in Figure 7, this very first time stamp message sink module 62 comprises: the first record cell 622, the first compensating unit 624 and the second record cell 626.The below describes this very first time stamp message sink module 62.

The first record cell 622 is used for the time that the logging timestamp message packet arrives receiving port;

The first compensating unit 624, be connected to the first record cell 622, be used for according to the first make-up time and/or the second make-up time the time that arrives receiving port being compensated, wherein, this first make-up time is that the time-stamping messages message arrives the time-delay between receiving port and the corresponding physical port of arrival receiving port, and this second make-up time is the processing time that receives this time-stamping messages message process;

The second record cell 626 is connected to the first compensating module 624, the time that obtains after being used for compensating the time of this time-stamping messages message arrival receiving port, is recorded as the time that receives this time-stamping messages message.

Fig. 8 is the structured flowchart of the second time-stamping messages receiver module in the time synchronism apparatus according to the preferred embodiment of the invention; This second time-stamping messages receiver module 64 comprises: the 3rd record cell 642, the second compensating unit 644 and the 4th record cell 646.The below describes this second time-stamping messages receiver module 64.

The 3rd record cell 642 is used for the time that the logging timestamp message packet arrives transmit port;

The second compensating unit 644, be connected to the 3rd record cell 642, be used for according to the 3rd make-up time and/or the 4th make-up time the time that arrives transmit port being compensated, wherein, the 3rd make-up time was that the time-stamping messages message arrives the time of transmit port and the error of the actual time that sends, the processing time of the 4th make-up time for the temporal information that is used for time synchronized is revised;

The 4th record cell 646 is connected to the second compensating module 644, the time that obtains after being used for compensating the time of time-stamping messages message arrival transmit port, is recorded as the time by transmit port transmitting time stamp message packet.

A kind of time synchronizing system also is provided in the present embodiment, this system comprises: clock equipment, from clockwork, optical line terminal OLT, optical network unit ONU, also comprise: the device of above-described embodiment or preferred embodiment, wherein, this device is connected to clock equipment and between the clockwork, clock equipment, is one of following from the pass between clockwork, OLT and the ONU: clock equipment and be independent of respectively OLT and ONU from clockwork; Clock equipment is positioned on the OLT, is independent of OLT and ONU from clockwork; Clock equipment is independent of OLT and ONU, is positioned on the ONU from clockwork; Clock equipment is positioned on the OLT, is positioned on the ONU from clockwork.

At present embodiment and preferred embodiment, by introducing the concept of TC transparent clock, for EPON, the method for synchronizing time that a kind of cost is low, design complexities is low, reliability is high is provided, and the corresponding network equipment and distributed clock synchronization system, to satisfy the synchronisation requirement of real-time service.Need to prove that these advantages are not the effect that above-mentioned all embodiment all can obtain, some effect is that some preferred implementation just can obtain.

Describe below in conjunction with a preferred embodiment, need to prove, the preferred embodiment combines above-described embodiment and preferred implementation.

In this preferred embodiment, a kind of computational methods of synchronous time of passive optical network are provided, according to the self-defining time-stamping messages form of this preferred embodiment, and corresponding handling process, by introducing TC transparent clock concept, EPON integral body is regarded as the TC transparent clock, calculate the time-stamping messages message through the residence time of EPON, and revise this timestamp, and network master clock and network are obtained synchronously from clock, synchronization accuracy and accuracy are improved simultaneously.The computational methods of this lock in time comprise the steps:

S1, master clock and carry out intercommunication by the time-stamping messages message from clock obtains synchronously.The time-stamping messages message can be the NTP message packet, also can be the IEEE1588 message packet, also can be other identical or similar packet-based synchronous protocol time-stamping messages message, and concrete implementation method is with reference to figure 2.

There are a local system clock in S2, EPON, OLT and ONU by ITU-T G.984.3AD2 or G.987.3 or IEEE802.1as make OLT and ONU be synchronized to EPON local system clock.

S3, downgoing time stamp message packet sends from master clock, (this port can be the outside first line of a couplet port of OLT to arrive the passive optical network OLT port, also can be inner self-defined port), this downgoing time stamp message packet arrived EPON local system time T 1 corresponding to this port and went on record this moment, this temporal information T1 is inserted into downgoing time stamp message packet, and this message continues downstream ONU forwarding in EPON afterwards.

S4, local system time T 1 is inserted into downgoing time stamp message packet and realizes according to the message format that the embodiment of the invention provides.

S5, the downgoing time stamp message packet that carries local system time T 1 arrives the ONU port, and (this port can be ONU external user port, also can be inner self-defined port), EPON local system time corresponding to this moment is T2, through processing the difference Δ T that gets T2-T1 _DownRevise downgoing time stamp message packet, downgoing time stamp message packet process is by Δ T _DownAfter the correction, the T1 record that then originally was inserted into is stripped from, and the time-stamping messages message continues to transmit (perhaps the T1 record is not stripped from, and mainly decides on concrete networking and equipment form) from clockwork.

S6, up time-stamping messages message is from sending from clock, (this port can be ONU external user port through EPON ONU port, also can be inner self-defined port), up time-stamping messages message arrived EPON local system time T 3 corresponding to this port and went on record this moment, this temporal information T3 is inserted into up time-stamping messages message, and this message continues upstream OLT forwarding in EPON afterwards.

S7, local system time T 3 is inserted into up time-stamping messages message and realizes according to the message format that the embodiment of the invention provides.

S8, the up time-stamping messages message that carries local system time T 3 arrives the OLT port, and (this port can be the outside first line of a couplet port of OLT, also can be inner self-defined port), EPON local system time corresponding to this moment is T4, through processing the difference Δ T that gets T4-T3 _UpRevise up time-stamping messages message, up time-stamping messages message process is by Δ T _UpAfter the correction, the T3 record that then originally was inserted into is stripped from, and the time-stamping messages message continues to transmit (perhaps the T3 record is not stripped from, and mainly decides on concrete networking and equipment form) to clock equipment.

(this port can be the outside first line of a couplet port of OLT at the OLT port by calculating up-downgoing time-stamping messages message, also can be inner self-defined port) and the ONU port (this port can be ONU external user port, also can be inner self-defined port) between residence time and revise corresponding up-downgoing time-stamping messages message, introduce the concept of similar IEEE1588TC transparent clock, network master clock and network are sent out by message mutually from clock like this, just can obtain each other synchronously.

A kind of passive optical network equipment (having realized the function of time synchronizing device) also is provided in the present embodiment, this passive optical network equipment comprises: EPON local system clock synchronous processing module, the time-stamping messages receiver module, EPON local system time insert module, the time-stamping messages sending module, time-stamping messages code correcting module, EPON local system time strip module, the below describes above-mentioned module.

EPON local system clock synchronous processing module: mainly by ITU-T G.984.3AD2 or G.987.3 or the time synchronizing method of IEEE802.1as realize OLT and ONU both sides' local clock and EPON local system clock synchronous separately.

Time-stamping messages receiver module: be mainly used in recognition time stamp message packet, can distinguish time-stamping messages message and other data messages by protocol type or self-defining method.This module can be processed from master clock and the time-stamping messages message that sends from clock, also can identify through the time-stamping messages message from EPON inside after revising.This module also is responsible for recorded message and is reached EPON local system time corresponding to this module simultaneously, this module also has the time bias function in addition, to compensate the actual time error that arrives this module of this resume module time and message etc., so that the accuracy of the local system time that this time-stamping messages message is recorded is improved.Time-stamping messages message and corresponding EPON local system time are preserved one to one.

EPON local system time insert module: be mainly used in modification time stamp message.Time-stamping messages receiver module transmitting time stamp message and corresponding EPON local system time are given this module, this module is by processing, message format according to embodiment of the invention appointment, form inserts the EPON local system time in the time-stamping messages message of correspondence as shown in Figure 9.

Time-stamping messages sending module: be mainly used in sending through the time-stamping messages message after revising (such as the time-stamping messages message after inserting and peeling off).

Time-stamping messages code correcting module (having realized the function of above-mentioned correcting module): (this port can be the outside first line of a couplet port of OLT at the OLT port to be mainly used in stabbing computing time message, also can be inner self-defined port) and the ONU port (this port can be ONU external user port, also can be inner self-defined port) between residence time, and the time-stamping messages message revised.This module also has the time bias function, with compensate this resume module time and from this module to message actual time error that sends etc. so that the accuracy of the residence time that is corrected is improved.

EPON local system time strip module: be mainly used in modification time stamp message.Time-stamping messages code correcting module sends and is corrected time-stamping messages to this module, and this module peels off the EPON local system time that is inserted into by processing, with the original form of recovery time stamp message packet.

The network architecture below in conjunction with different PON describes.

Preferred architecture one

The network system of this framework comprises optical line terminal OLT 1, at least one above-mentioned passive optical network equipment, at least one optical network unit ON U1, at least one outside clock equipment and outside from clockwork.

Optical line terminal OLT 1: be mainly used in receiving transmitting time stamp message packet.The time-stamping messages message that reception sends from the outside master clock of OLT1, and send to passive optical network equipment and processed, passive optical network equipment sends for its time-stamping messages message by OLT1.OLT1 is also responsible in addition finds range to the ONU1 in the system, relevant ranging information is sent to passive optical network equipment process, and also is responsible for and the ONU1 intercommunication, and assurance time-stamping messages message is transmitted between OLT1 and ONU1 normally.

Optical network unit ONU 1: be mainly used in receiving transmitting time stamp message packet.The time-stamping messages message that reception sends from the ONU1 outside from clock, and send to passive optical network equipment and processed, passive optical network equipment sends to outside from clock for its time-stamping messages message by ONU1.ONU1 also is responsible for and the OLT1 intercommunication in addition, and assurance OLT1 range finding is normally carried out, and assurance time-stamping messages message is transmitted between OLT1 and ONU1 normally.

Passive optical network equipment: mainly for the treatment of the time-stamping messages message that sends over from OLT1 and ONU1, the message packet after the transmission processing is to OLT1 and ONU1 simultaneously.This equipment also is responsible for processing the ranging information that OLT1 sends in addition, and makes the ONU1 local clock, OLT1 local clock and EPON local system clock synchronous.

Master-salve clock equipment: clock equipment is time server, such as IEEE1588 equipment, can be that master clock also can be the BC boundary clock, is IEEE1588 client client from clockwork.

Preferred architecture two

The network system of this framework comprises optical line terminal OLT 1, at least one above-mentioned passive optical network equipment, at least one optical network unit ONU 2 and at least one clock equipment.

Optical line terminal OLT 1: be mainly used in receiving transmitting time stamp message packet.The time-stamping messages message that reception sends from the outside master clock of OLT1, and send to passive optical network equipment and processed, passive optical network equipment sends for its time-stamping messages message by OLT1.OLT1 is also responsible in addition finds range to the ONU2 in the system, relevant ranging information is sent to passive optical network equipment process, and also is responsible for and the ONU2 intercommunication, and assurance time-stamping messages message is transmitted between OLT1 and ONU2 normally.

Optical network unit ONU 2: be mainly used in receiving transmitting time stamp message packet.Become in addition the part of ONU2 above clockwork is placed on ONU2, ONU2 mainly is responsible for and passive optical network equipment carries out time information receiving and transmitting intercommunication.ONU2 is upper to send to passive optical network equipment and processed from clock time stamp message packet, and passive optical network equipment is sent to processing from clockwork above the ONU2 for its time-stamping messages message.ONU2 also is responsible for and the OLT1 intercommunication in addition, and assurance OLT1 range finding is normally carried out, and assurance time-stamping messages message is transmitted between OLT1 and ONU2 normally.

Passive optical network equipment: mainly for the treatment of the time-stamping messages message that sends over from OLT1 and ONU2, the message packet after the transmission processing is to OLT1 and ONU2 simultaneously.This equipment also is responsible for processing the ranging information that OLT sends in addition, and makes the ONU2 local clock, OLT1 local clock and EPON local system clock synchronous.

Clock equipment: clock equipment is time server, such as IEEE1588 equipment, can be that master clock also can be the BC boundary clock.

Preferred architecture three

The network system of this framework comprises optical line terminal OLT 2, at least one above-mentioned passive optical network equipment, and one of at least one optical network unit ONU 1 and correspondence from clockwork.

Optical line terminal OLT 2: be mainly used in receiving transmitting time stamp message packet.Clock equipment is placed on a part that becomes OLT2 above the OLT2 in addition, and the OLT2 clock equipment mainly is responsible for and passive optical network equipment carries out time information receiving and transmitting intercommunication, and it also is responsible for carrying out message intercommunication with upstream clock equipment simultaneously, to obtain synchronously.If the source of OLT2 upstream equipment is similar IEEE1588 time server, the OLT2 clock equipment is as the IEEE1588BC boundary clock, it is responsible for and the time of upstream is carried out the time message intercommunication to obtain synchronously by server, if the OLT2 upstream equipment is the global navigation satellite time dissemination system, it directly obtains time synchronization information from time dissemination system.OLT2 is also responsible in addition finds range to the ONU1 in the system, relevant ranging information is sent to passive optical network equipment process, and also is responsible for and the ONU1 intercommunication, and assurance time-stamping messages message is transmitted between OLT2 and ONU1 normally.

Optical network unit ONU 1: be mainly used in receiving transmitting time stamp message packet.The time-stamping messages message that reception sends from the ONU1 outside from clock also sends to passive optical network equipment and processed, and passive optical network equipment sends to outside from clock for its time-stamping messages message by ONU1.ONU1 also is responsible for and the OLT2 intercommunication in addition, and assurance OLT2 range finding is normally carried out, and assurance time-stamping messages message is transmitted between OLT2 and ONU1 normally.

Passive optical network equipment: mainly for the treatment of the time-stamping messages message that sends over from OLT2 and ONU1, the message packet after the transmission processing is to OLT2 and ONU1 simultaneously.This equipment also is responsible for processing the ranging information that OLT2 sends in addition, and makes the ONU1 local clock, OLT2 local clock and EPON local system clock synchronous.

From clockwork: be IEEE1588 client client from clockwork.

Preferred architecture four

The network system of this framework comprises optical line terminal OLT 2, at least one above-mentioned passive optical network equipment, at least one optical network unit ONU 2.

Optical line terminal OLT 2: be mainly used in receiving transmitting time stamp message packet.Clock equipment is placed on a part that becomes OLT2 above the OLT2 in addition, and the OLT2 clock equipment mainly is responsible for and passive optical network equipment carries out time information receiving and transmitting intercommunication, and it also is responsible for carrying out message intercommunication with upstream clock equipment simultaneously, to obtain synchronously.If the source of OLT2 upstream equipment is similar IEEE1588 time server, the OLT2 clock equipment is as the IEEE1588BC boundary clock, it is responsible for and the time of upstream is carried out the time message intercommunication to obtain synchronously by server, if the OLT2 upstream equipment is the global navigation satellite time dissemination system, it directly obtains time synchronization information from time dissemination system.OLT2 is also responsible in addition finds range to the ONU2 in the system, relevant ranging information is sent to passive optical network equipment process, and also is responsible for and the ONU2 intercommunication, and assurance time-stamping messages message is transmitted between OLT2 and ONU2 normally.

Optical network unit ONU 2: be mainly used in receiving transmitting time stamp message packet.Become in addition the part of ONU2 above clockwork is placed on ONU2, ONU2 mainly is responsible for and passive optical network equipment carries out time information receiving and transmitting intercommunication.ONU2 is upper to send to passive optical network equipment and processed from clock time stamp message packet, and passive optical network equipment is sent to processing from clockwork above the ONU2 for its time-stamping messages message.ONU2 also is responsible for and the OLT2 intercommunication in addition, and assurance OLT2 range finding is normally carried out, and assurance time-stamping messages message is transmitted between OLT2 and ONU2 normally.

Passive optical network equipment: mainly for the treatment of the time-stamping messages message that sends over from OLT2 and ONU2, the message packet after the transmission processing is to OLT2 and ONU2 simultaneously.This equipment also is responsible for processing the ranging information that OLT2 sends in addition, and makes the ONU2 local clock, OLT2 local clock and EPON local system clock synchronous.

A kind of optical line terminal OLT 1 also is provided in this preferred embodiment, has mainly comprised: EPON local system clock synchronous processing module, time-stamping messages receiver module, EPON local system time insert module, time-stamping messages sending module, time-stamping messages code correcting module and EPON local system time strip module.

EPON local system clock synchronous processing module: be mainly used in by ITU-T G.984.3AD2 or G.987.3 or the time synchronizing method of IEEE802.1as realize OLT and ONU both sides local clock and EPON local system clock synchronous separately.

Time-stamping messages receiver module: be mainly used in recognition time stamp message packet, can distinguish time-stamping messages message and other data messages by protocol type or self-defining method.This module can be processed the time-stamping messages message that sends from outside upstream master clock, also can identify through the time-stamping messages message from inside, EPON downstream after revising.This module also is responsible for recorded message and is reached EPON local system time corresponding to this module simultaneously, this module also has the time bias function in addition, to compensate this module of the actual arrival of this resume module time and message time error etc., so that the accuracy of the local system time that this time-stamping messages message is recorded is improved.Time-stamping messages message and corresponding EPON local system time are preserved one to one.

EPON local system time insert module: be mainly used in modification time stamp message.Time-stamping messages receiver module transmitting time stamp message and corresponding EPON local system time are given this module, this module is by processing, according to the message format of appointment of the present invention, insert the EPON local system time in the time-stamping messages message of correspondence.

Time-stamping messages sending module: be mainly used in sending through the time-stamping messages message after revising (such as the time-stamping messages message after inserting and peeling off).Send through the standard message after the lift-off processing to OLT upstream clock equipment or send through the self-defined message after the insert handling to the OLT downstream from clockwork.

Time-stamping messages code correcting module: (this port can be ONU external user port at OLT first line of a couplet port (with upstream master clock communication interface) and ONU port to be mainly used in stabbing computing time message, it also can be inner self-defined port, mainly look from clock whether on ONU) between residence time, and the time-stamping messages message revised.This module also has the time bias function, with compensate this resume module time and from this module to message actual time error that sends etc. so that the accuracy of the residence time that is corrected is improved.

In the present embodiment, a kind of optical line terminal OLT 2 also is provided, has mainly comprised: clock equipment, EPON local system clock synchronous processing module, time-stamping messages receiver module, EPON local system time insert module, time-stamping messages sending module, time-stamping messages code correcting module and EPON local system time strip module.

Clock equipment, clock equipment is placed on above the OLT here, becomes the part of OLT.If the source of OLT upstream equipment is similar IEEE1588 time server, the OLT clock equipment is as the IEEE1588BC boundary clock, it is responsible for and the time of upstream is carried out the time message intercommunication to obtain synchronously by server, if the OLT upstream equipment is the global navigation satellite time dissemination system, it directly obtains time synchronization information from time dissemination system.

Time-stamping messages receiver module: be mainly used in recognition time stamp message packet, can distinguish time-stamping messages message and other data messages by protocol type or self-defining method.This module can be processed the time-stamping messages message that sends from internal master clock, also can identify through the time-stamping messages message from EPON inside after revising.This module also is responsible for recorded message and is reached EPON local system time corresponding to this module simultaneously, this module also has the time bias function in addition, to compensate this module of the actual arrival of this resume module time and message time error etc., so that the accuracy of the local system time that this time-stamping messages message is recorded is improved.Time-stamping messages message and corresponding EPON local system time are preserved one to one.

Time-stamping messages sending module: be mainly used in sending through the time-stamping messages message after revising (such as the time-stamping messages message after inserting and peeling off).Send through the standard message after the lift-off processing to the upper clock equipment of OLT or send through the self-defined message after the insert handling to the OLT downstream from clockwork.

Time-stamping messages code correcting module: (this port can be ONU external user port at OLT port (with the upper master clock communication interface of OLT) and ONU port to be mainly used in stabbing computing time message, it also can be inner self-defined port, mainly look from clock whether on ONU) between residence time, and the time-stamping messages message revised.This module also has the time bias function, with compensate this resume module time and from this module to message actual time error that sends etc. so that the accuracy of the residence time that is corrected is improved.

In the present embodiment, a kind of light network element ON U1 also is provided, has mainly comprised EPON local system clock synchronous processing module, time-stamping messages receiver module, EPON local system time insert module, time-stamping messages sending module, time-stamping messages code correcting module and EPON local system time strip module:

Time-stamping messages receiver module: be mainly used in recognition time stamp message packet, can distinguish time-stamping messages message and other data messages by protocol type or self-defining method.This module can be processed the time-stamping messages message that sends from clock from the outside, also can identify through the time-stamping messages message from upstream, EPON inside after revising.This module also is responsible for recorded message and is reached EPON local system time corresponding to this module simultaneously, this module also has the time bias function in addition, to compensate this module of the actual arrival of this resume module time and message time error etc., so that the accuracy of the local system time that this time-stamping messages message is recorded is improved.Time-stamping messages message and corresponding EPON local system time are preserved one to one.

Time-stamping messages sending module: be mainly used in sending through the time-stamping messages message after revising (such as the time-stamping messages message after inserting and peeling off).Send through the standard message after the insert handling to ONU upstream clock equipment or send through the self-defined message after the lift-off processing to the ONU downstream from clockwork.

Time-stamping messages code correcting module: (this port can be the outside first line of a couplet port of OLT at the OLT port to be mainly used in stabbing computing time message, also can be inner self-defined port) and the ONU port (this port can be ONU external user port, also can be inner self-defined port) between residence time, and the time-stamping messages message revised.This module also has the time bias function, with compensate this resume module time and from this module to message actual time error that sends etc. so that the accuracy of the residence time that is corrected is improved.

In the present embodiment, a kind of optical network unit ONU 2 also is provided, has mainly comprised from clockwork, EPON local system clock synchronous processing module, time-stamping messages receiver module, EPON local system time insert module, time-stamping messages sending module, time-stamping messages code correcting module and EPON local system time strip module:

From clockwork, above clockwork is placed on ONU, become the part of ONU here.

Time-stamping messages receiver module: be mainly used in recognition time stamp message packet, can distinguish time-stamping messages message and other data messages by protocol type or self-defining method.This module can be processed the upper time-stamping messages message that sends from clock from ONU, also can identify through the time-stamping messages message from upstream, EPON inside after revising.This module also is responsible for recorded message and is reached EPON local system time corresponding to this module simultaneously, this module also has the time bias function in addition, to compensate this module of the actual arrival of this resume module time and message time error etc., so that the accuracy of the local system time that this time-stamping messages message is recorded is improved.Time-stamping messages message and corresponding EPON local system time are preserved one to one.

Time-stamping messages sending module: be mainly used in sending through the time-stamping messages message after revising (such as the time-stamping messages message after inserting and peeling off).Send through the standard message after the insert handling upper from clockwork to ONU through the self-defined message after the lift-off processing to ONU upstream clock equipment or transmission.

Describe below in conjunction with another preferred embodiment, need to prove, the preferred embodiment combines above-described embodiment and preferred implementation.

In this preferred embodiment, defined a kind of timestamp form, Fig. 9 is the schematic diagram of timestamp form according to the preferred embodiment of the invention, as shown in Figure 9, original standard time stamp is made amendment, insert message and arrived local system time corresponding to EPON, local system temporal information form can be the similar IEEE1588 form of writing time: adopt the 48bit signless integer to record second, 32 bit record nanosecond without meeting integer, in this way expression time information, for example, 1ns represents with 0,000 0,000 0001 0000H, again for example, 2.5ns represents with 0,000 0,000 0002 8000H; Also can adopt in addition such as the mode of " Hour Minute Second nanosecond date " and come expression time, such as 5 o'clock 06 minute 28 seconds 2.5 nanoseconds of on January 24th, 2009, the expression mode of nanosecond is with above-mentioned identical.Original timestamp information has been kept by complete, is placed on local system corresponding to EPON after the time.

Figure 10 is time synchronized computational methods system architecture diagram according to the preferred embodiment of the invention, Figure 11 be the preferred embodiment according to the present invention lock in time method flow chart, as shown in figure 11, corresponding to the system architecture diagram of Figure 10, this flow process comprises the steps:

Step S1102, master-salve clock carries out intercommunication by the time-stamping messages message, obtains synchronously, and the mode of similar IEEE1588 twoway realizes synchronously, such as formula (1)～formula (5).

Step S1104, OLT and ONU by ITU-T G.984.3AD2 or G.987.3 or IEEE802.1as make OLT and ONU be synchronized to EPON local system clock, an EPON local system of the upper existence of OLT clock processing module, also have an EPON local system clock processing module above the ONU, both send out mutually timing code message and can obtain synchronously.As shown in figure 10, the EPON local system clock of indication can exist on OLT and also can exist on ONU here, but generally all is arranged on above the OLT, is responsible for maintenance by OLT.

Step S1106, downgoing time stamp message packet sends from master clock, arrive passive optical network OLT port (this port can be the outside first line of a couplet port of OLT, also can be inner self-defined port), corresponding local EPON local system time T 1 goes on record constantly.

Step S1108, then this downlink message as shown in Figure 9, is inserted into constantly message of T1 according to the form of the above-mentioned definition of this preferred embodiment, then continues to transmitting from clockwork.

Step S1110, the downgoing time stamp message packet that carries T1 arrives ONU port (this port can be ONU external user port, also can be inner self-defined port), and this moment, local EPON local system time T 2 went on record constantly.

Step S1112 is through processing the difference Δ T that gets T2-T1 _DownRevise downgoing time stamp message packet, illustrate here and how to revise the IEEE1588 processing mode, according to IEEE1588 principle and TC clock processing mode, descending IEEE1588event message:

SYNC message residence time is: Δ T _Down=T2-T1,

If TC clock (EPON integral body is treated as the TC clock) is one step clock, so should be this Δ T during the ONU outbound port _DownParameter is added to SYNC message correctionField territory.

If the TC clock is two step clock, so should be this Δ T during the ONU outbound port _DownParameter is added to Follow_Up message correctionField territory.

Downgoing time stamp message packet is through after being corrected, and the T1 record that then originally was inserted into is stripped from, and the time-stamping messages message continues to transmit (perhaps the T1 record is not stripped from, and mainly decides on concrete networking and equipment form) from clockwork.

Step S1114, up time-stamping messages message sends from master clock, arrive EPON ONU port (this port can be ONU external user port, also can be inner self-defined port), corresponding local EPON local system time T 3 goes on record constantly.

Step S1116, then this uplink message is inserted into constantly message of T3 according to the form of preferred embodiment of the present invention definition, then continues to transmit to clock equipment.

Step S1118, the downgoing time stamp message packet that carries T3 arrives OLT port (this port can be the outside first line of a couplet port of OLT, also can be inner self-defined port), and this moment, corresponding local EPON local system time T 4 went on record constantly.

Step S1120 is through processing the difference Δ T that gets T4-T3 _UpRevise up time-stamping messages message, up time-stamping messages message is through after being corrected, then the T3 record that originally was inserted into is stripped from, the time-stamping messages message continues to transmit (perhaps the T3 record is not stripped from, and mainly decides on concrete networking and equipment form) to clock equipment.Here illustrate and how to revise the IEEE1588 processing mode, according to IEEE1588 principle and TC clock processing mode, up IEEE1588 eventmessage:

Delay_Req message residence time is: Δ T _Up=T4-T3,

If the TC clock is one step clock, so should be this Δ T during the OLT outbound port _UpParameter deducts from Delay_Req message correctionField territory.

If the TC clock is two step clock, so should be this Δ T during the OLT outbound port _UpParameter is added to Delay_Req message correctionField territory, and then the IEEE1588 Master equipment of upstream deducts this parameter again from Delay_Resp message correctionField territory and sends.

Finally, master-salve clock is according to the intercommunication of time-stamping messages message, by the mode of class IEEE1588, obtains synchronously such as the mode of formula (1)～formula (5).

In this preferred embodiment, a kind of passive optical network equipment also is provided, Figure 12 is the structured flowchart of passive optical network equipment according to the preferred embodiment of the invention, as shown in figure 12, this passive optical network equipment comprises: EPON local system clock synchronous processing module 02-1 and 02-2, time-stamping messages receiver module 01-1 and 01-2, time-stamping messages sending module 06-1 and 06-2, EPON local system time insert module 05-1 and 05-2, EPON local system time strip module 04-1 and 04-2, time-stamping messages code correcting module 03-1 and 03-2.Need to prove that the internal interface among the figure is relative passive optical network equipment and master-salve clock with external interface.External interface: interacting message interface between master-salve clock and the passive optical network equipment.Internal interface: interacting message interface between the passive optical network equipment internal module.Figure 13 is the flow chart of passive optical network equipment method for synchronizing time according to the preferred embodiment of the invention, and as shown in figure 13, this flow process comprises the steps:

Step S1302, master-salve clock carries out intercommunication by the time-stamping messages message, obtains synchronously, and the mode of similar IEEE1588 twoway realizes synchronously, concrete principle and computing formula such as formula (1)～formula (5).

Step S1304, EPON local system clock synchronous processing module 02-1 and 02-2, by ITU-T G.984.3AD2 or G.987.3 or the time synchronizing method of IEEE802.1as realize OLT and ONU both sides' local clock and EPON local system clock synchronous separately.

Step S1306, (the local system clock can be at OLT after 02-1 module, 02-2 module and local system clock synchronous, also can be at ONU, generally all be arranged on OLT, safeguarded by OLT), the 02-1 module provides the EPON local system time to do timing reference to the 01-1 module, and the 02-2 module provides the EPON local system time to do timing reference to the 01-2 module.

Step S1308, stab message sink module 01-1 the time of advent from outside port downgoing time stamp message packet, message is recorded and arrives EPON local system time corresponding to 01-1 is T1, and the 01-1 module also has the time bias function in addition, to compensate this resume module time Δ T _P-d1 and this module of the actual arrival of message time error, because message arrived between the time that optical network device time and message packet arrive the OLT physical port time-delay Δ T is arranged _P-d2, so that the accuracy of this time-stamping messages message time of advent is improved, the actual local zone time that is corrected like this is by compensation:

T1 '=(T1-Δ T _P-d1-Δ T _P-d2) formula (6)

Here represent Δ T with T1 ' _P-d1, Δ T _P-d2 can revise by the mode of software, also can by the mode of hardware, directly obtain Δ T according to formula (6) _P-d1, Δ T _P-d2 can be set to 0.The EPON local system time T 1 of time-stamping messages message and correspondence ' preserved one to one.

Step S1310, T1 ' the information of carrying downgoing time stamp message packet and correspondence is sent to EPON local system time insert module 05-1 and processes, T1 ' information as shown in Figure 9, is inserted in this downgoing time stamp message packet according to definition format of the present invention.

Step S1312, the downgoing time stamp message packet that carries T1 ' information is sent to time-stamping messages sending module 06-1, is sent at last OLT PON mouth and is forwarded to descending from clock.

Step S1314, the downgoing time stamp message packet that carries T1 ' information stabs message sink module 01-2 the time of advent, message is recorded and arrives EPON local system time corresponding to 01-2 is T2, and time-stamping messages message and corresponding EPON local system time T 2 are preserved one to one.

Step S1316, downgoing time stamp message packet and the corresponding T2 information of carrying T1 ' information are sent to time-stamping messages code correcting module 03-2, and the 03-2 module also has the time bias function, to compensate this resume module time Δ T _P-d3 and from this module to message the actual time error Δ T that sends _P-d4 etc., by compensation so that the accuracy of the residence time that is corrected be improved, so actual sending to from the time of clock is:

T2 '=(T1+ Δ T _P-d3+ Δ T _P-d4) formula (7)

Here represent Δ T with T2 ' _P-d3, Δ T _P-d4 can revise by the mode of software, also can by the mode of hardware, directly obtain Δ T according to formula (7) _P-d3, Δ T _P-d4 can be set to 0.At last by Δ T _Down=T2 '-T1 ', then the actual residence time of acquisition downlink message revises this time-stamping messages message, concrete correcting mode refer step S1120.

Step S1318, the downgoing time that is corrected stamp message packet is sent to EPON local system time strip module 04-2, is reduced into after treatment downgoing time stamp message packet reference format.

Step S1320, after revising and the time-stamping messages message of being stripped from directly be sent to from clockwork.

Step S1322, stab message sink module 01-2 the time of advent from the up time-stamping messages message of outside port, message is recorded and arrives EPON local system time corresponding to 01-2 is T3, and the 01-2 module also has the time bias function in addition, to compensate this resume module time Δ T _P-u1 and this module of the actual arrival of message time error, because message arrived between the time that optical network device time and message packet arrive the ONU physical port time-delay Δ T is arranged _P-u2, so that the accuracy of this time-stamping messages message time of advent is improved, the actual local zone time that is corrected like this is by compensation:

T3 '=(T3-Δ T _P-u1-Δ t _P-u2) formula (8)

Here represent Δ T with T3 ' _P-u1, Δ T _P-u2 can revise by the mode of software, also can by the mode of hardware, directly obtain Δ T according to formula (8) _P-u1, Δ T _P-u2 can be set to 0.The EPON local system time T 3 of time-stamping messages message and correspondence ' preserved one to one.

Step S1324, T3 ' the information of carrying up time-stamping messages message and correspondence is sent to EPON local system time insert module 05-2 and processes, T3 ' information as shown in Figure 9, is inserted in this downgoing time stamp message packet according to definition format of the present invention.

Step S1326, the up time-stamping messages message that carries T3 ' information is sent to time-stamping messages sending module 06-2, is sent at last OLT PON mouth and is forwarded to up master clock.

Step S1328, the up time-stamping messages message that carries T3 ' information stabs message sink module 01-1 the time of advent, message is recorded and arrives EPON local system time corresponding to 01-1 is T4, and time-stamping messages message and corresponding EPON local system time T 4 are preserved one to one.

Step S1330, up time-stamping messages message and the corresponding T4 information of carrying T3 ' information are sent to time-stamping messages code correcting module 03-1, and the 03-1 module also has the time bias function, to compensate this resume module time Δ T _P-u3 and from this module to message the actual time error Δ T that sends _P-u4 etc., by compensating so that the accuracy of the residence time that is corrected is improved, so the actual time that sends to master clock is:

T4 '=(T1+ Δ T _P-u3+ Δ T _P-u4) formula (9)

Here represent Δ T with T4 ' _P-u3, Δ T _P-u4 can revise by the mode of software, also can by the mode of hardware, directly obtain Δ T according to formula (9) _P-u3, Δ T _P-u4 can be set to 0.At last by Δ T _Up=T4 '-T3 ', then the actual residence time of acquisition uplink message revises this time-stamping messages message, concrete correcting mode refer step S1120.

Step S1332, the up time-stamping messages message that is corrected is sent to EPON local system time strip module 04-1, is reduced into after treatment downgoing time stamp message packet reference format.

Step S1334, after revising and the time-stamping messages message of being stripped from directly be sent to clock equipment.

At last, master-salve clock carries out intercommunication by the time-stamping messages message, obtains synchronously, and the mode of similar IEEE1588 two way realizes synchronously, such as formula (1)～formula (5).

In this preferred embodiment, a kind of network system 1 is provided, Figure 14 is the schematic diagram according to the network system of the preferred embodiment of the present invention one, as shown in figure 14, this network system comprises: the passive optical network equipment of optical line terminal OLT 1, at least one above-described embodiment or preferred embodiment, at least one optical network unit ONU 1, at least one outside clock equipment and outside from clockwork:

Optical network unit ONU 1: be mainly used in receiving transmitting time stamp message packet.The time-stamping messages message that reception sends from the ONU1 outside from clock also sends to passive optical network equipment and processed, and passive optical network equipment sends to outside from clock for its time-stamping messages message by ONU1.ONU1 also is responsible for and the OLT1 intercommunication in addition, and assurance OLT1 range finding is normally carried out, and assurance time-stamping messages message is transmitted between OLT1 and ONU1 normally.

Master-salve clock equipment: clock equipment is time server, such as IEEE1588 equipment, can be that master clock also can be the BC boundary clock, is the IEEE1588client client from clockwork.

In this preferred embodiment, a kind of network system 2 also is provided, Figure 15 is the schematic diagram according to the network system of the preferred embodiment of the present invention two, as shown in figure 15, this network system comprises: the passive optical network equipment of optical line terminal OLT 1, at least one above-described embodiment or preferred embodiment, at least one optical network unit ONU 2 and at least one clock equipment.

In this preferred embodiment, a kind of network system 3 is provided, Figure 16 is the schematic diagram according to the network system of the preferred embodiment of the present invention three, as shown in figure 16, this network system: comprise the passive optical network equipment of optical line terminal OLT 2, at least one above-described embodiment or preferred implementation, one of at least one optical network unit ONU 1 and correspondence from clockwork.

From clockwork: be the IEEE1588client client from clockwork.

In this preferred embodiment, a kind of network system 4 is provided, Figure 17 is the schematic diagram according to the network system of the preferred embodiment of the present invention four, as shown in figure 17, this network system comprises: the passive optical network equipment of optical line terminal OLT 2, at least one above-described embodiment or preferred implementation, at least one optical network unit ONU 2.

In the present embodiment, a kind of optical line terminal OLT 1 is provided, Figure 18 is the flow chart of implementing according to the optical line terminal one of the embodiment of the invention, need to prove that the internal interface among the figure is relative passive optical network equipment and master-salve clock with external interface.External interface: interacting message interface between master-salve clock and the passive optical network equipment.Internal interface: interacting message interface between the passive optical network equipment internal module.As shown in figure 18, this flow process comprises the steps:

S1, optical network device 02-1 module and downstream ONU communicate news, by ITU-T G.984.3AD2 or G.987.3 or the time synchronizing method of IEEE802.1as realize OLT and ONU both sides' local clock and EPON local system clock synchronous separately, and provide the EPON local system time to do timing reference to the 01-1 module.

S2, from the next master clock time-stamping messages message of OLT, arriving optical network device 01-1 processes, message is recorded and arrives EPON local system time corresponding to 01-1 is T1, the 01-1 module also has the time bias function in addition, to compensate the time error of this module of the actual arrival of this resume module time and message, because message arrived between the time that optical network device time and message packet arrive the OLT physical port time-delay is arranged, by compensation so that the accuracy of this time-stamping messages message time of advent be improved.

S3, then this downgoing time stamp message packet and corresponding T1 information are sent to optical network device 05-1 module and process.T1 information as shown in Figure 9, is inserted in this downgoing time stamp message packet according to definition format of the present invention.

S4, the downgoing time stamp message packet that carries T1 information is sent to optical network device 06-1 module and processes, and is sent at last OLT PON mouth and is forwarded to descending from clock.

S5, arriving optical network device 01-1 module from the up time-stamping messages message in EPON inside processes, message is recorded and arrives EPON local system time corresponding to 01-1 is T4, and time-stamping messages message and corresponding EPON local system time T 4 are preserved one to one.

S6, this up time-stamping messages message and corresponding T4 information are sent to optical network device 03-1 module and process, the 03-1 module also has the time bias function, with compensate this resume module time and from this module to message the actual time error that sends etc., by compensation so that the accuracy of the residence time that is corrected be improved.By calculating the actual residence time that obtains uplink message, then revise this time-stamping messages message, concrete correcting mode is with reference to above-described embodiment and preferred embodiment.

S7, the up time-stamping messages message that is corrected is sent to optical network device 04-1 module and processes, and is reduced into up time-stamping messages message reference format through after the lift-off processing.

S8 is sent to optical network device 05-1 module finally by revising time-stamping messages message rear and that be stripped from, is sent to outside clock equipment.

In the present embodiment, a kind of optical line terminal OLT 2 is provided, Figure 19 is the flow chart of implementing according to the optical line terminal two of the embodiment of the invention, need to prove that the internal interface among the figure is relative passive optical network equipment and master-salve clock with external interface.External interface: interacting message interface between master-salve clock and the passive optical network equipment.Internal interface: interacting message interface between the passive optical network equipment internal module.As shown in figure 19, this flow process comprises the steps:

S1, clock equipment, clock equipment is placed on above the OLT here, becomes the part of OLT.If the source of OLT upstream equipment is similar IEEE1588 time server, the OLT clock equipment is as the IEEE1588BC boundary clock, it is responsible for and the time of upstream is carried out the time message intercommunication to obtain synchronously by server, if the OLT upstream equipment is the global navigation satellite time dissemination system, it directly obtains time synchronization information from time dissemination system.

S2, optical network device 02-1 module and downstream ONU communicate news, by ITU-T G.984.3AD2 or G.987.3 or the time synchronizing method of IEEE802.1as realize OLT and ONU both sides' local clock and EPON local system clock synchronous separately, and provide the EPON local system time to do timing reference to the 01-1 module.

S3, from the upper master clock time-stamping messages message of OLT, arriving optical network device 01-1 processes, message is recorded and arrives EPON local system time corresponding to 01-1 is T1, the 01-1 module also has the time bias function in addition, to compensate the time error of this module of the actual arrival of this resume module time and message, by compensation so that the accuracy of this time-stamping messages message time of advent be improved.

S4, then this downgoing time stamp message packet and corresponding T1 information are sent to optical network device 05-1 module and process.T1 information as shown in Figure 9, is inserted in this downgoing time stamp message packet according to definition format of the present invention.

S5, the downgoing time stamp message packet that carries T1 information is sent to optical network device 06-1 module and processes, and is sent at last OLT PON mouth and is forwarded to descending from clock.

S6, arriving optical network device 01-1 module from the up time-stamping messages message in EPON inside processes, message is recorded and arrives EPON local system time corresponding to 01-1 is T4, and time-stamping messages message and corresponding EPON local system time T 4 are preserved one to one.

S7, this up time-stamping messages message and corresponding T4 information are sent to optical network device 03-1 module and process, the 03-1 module also has the time bias function, with compensate this resume module time and from this module to message the actual time error that sends etc., by compensation so that the accuracy of the residence time that is corrected be improved.By calculating the actual residence time that obtains uplink message, then revise this time-stamping messages message, concrete correcting mode is with reference to above-described embodiment and preferred embodiment.

S8, the up time-stamping messages message that is corrected is sent to optical network device 04-1 module and processes, and is reduced into up time-stamping messages message reference format through after the lift-off processing.

S9 is sent to optical network device 05-1 module finally by revising time-stamping messages message rear and that be stripped from, is sent to the upper clock equipment of OLT.

In the present embodiment, a kind of optical network unit ONU 1 is provided, Figure 20 is the flow chart of implementing according to the optical network unit one of the embodiment of the invention, need to prove that the internal interface among the figure is relative passive optical network equipment and master-salve clock with external interface.External interface: interacting message interface between master-salve clock and the passive optical network equipment.Internal interface: interacting message interface between the passive optical network equipment internal module.As shown in figure 20, this flow process comprises the steps:

S1, optical network device 02-2 module and upstream OLT communicate news, by ITU-T G.984.3AD2 or G.987.3 or the time synchronizing method of IEEE802.1as realize OLT and ONU both sides' local clock and EPON local system clock synchronous separately, and provide the EPON local system time to do timing reference to the 01-2 module.

S2, stab message packet from what ONU came from clock time, arriving optical network device 01-2 processes, message is recorded and arrives EPON local system time corresponding to 01-2 is T3, the 01-2 module also has the time bias function in addition, to compensate the time error of this module of the actual arrival of this resume module time and message, because message arrived between the time that optical network device time and message packet arrive the ONU physical port time-delay is arranged, by compensation so that the accuracy of this time-stamping messages message time of advent be improved.

S3, then this up time-stamping messages message and corresponding T3 information are sent to optical network device 05-2 module and process.T3 information as shown in Figure 9, is inserted in this up time-stamping messages message according to definition format of the present invention.

S4, the up time-stamping messages message that carries T3 information is sent to optical network device 06-2 module and processes, and is sent at last ONU PON mouth and is forwarded to up master clock.

S5, arriving optical network device 01-2 module from EPON inside downgoing time stamp message packet processes, message is recorded and arrives EPON local system time corresponding to 01-2 is T2, and time-stamping messages message and corresponding EPON local system time T 2 are preserved one to one.

S6, this downgoing time stamp message packet and corresponding T2 information are sent to optical network device 03-2 module and process, the 03-2 module also has the time bias function, with compensate this resume module time and from this module to message the actual time error that sends etc., by compensation so that the accuracy of the residence time that is corrected be improved.By calculating the actual residence time that obtains uplink message, then revise this time-stamping messages message, concrete correcting mode is with reference to above-described embodiment and preferred embodiment.

S7, the downgoing time that is corrected stamp message packet is sent to optical network device 04-2 module and processes, through being reduced into downgoing time stamp message packet reference format after the lift-off processing.

S8 is sent to optical network device 05-2 module finally by revising time-stamping messages message rear and that be stripped from, is sent to outside from clockwork.

In the present embodiment, a kind of optical network unit ONU 2 is provided, Figure 21 is the flow chart of implementing according to the optical network unit two of the embodiment of the invention, need to prove that the internal interface among the figure is relative passive optical network equipment and master-salve clock with external interface.External interface: interacting message interface between master-salve clock and the passive optical network equipment.Internal interface: interacting message interface between the passive optical network equipment internal module.As shown in figure 21, this flow process comprises the steps:

S1 from clockwork, above clockwork is placed on ONU, becomes the part of ONU here.

S2, optical network device 02-2 module and upstream OLT communicate news, by ITU-T G.984.3AD2 or G.987.3 or the time synchronizing method of IEEE802.1as realize OLT and ONU both sides' local clock and EPON local system clock synchronous separately, and provide the EPON local system time to do timing reference to the 01-2 module.

S3, from the upper time-stamping messages message that comes from clock of ONU, arriving optical network device 01-2 processes, message is recorded and arrives EPON local system time corresponding to 01-2 is T3, the 01-2 module also has the time bias function in addition, to compensate this module of the actual arrival of this resume module time and message time error, because message arrived between the time that optical network device time and message packet arrive the ONU physical port time-delay is arranged, by compensation so that the accuracy of this time-stamping messages message time of advent be improved.

S4, then this up time-stamping messages message and corresponding T3 information are sent to optical network device 05-2 module and process.T3 information as shown in Figure 9, is inserted in this up time-stamping messages message according to definition format of the present invention.

S5, the up time-stamping messages message that carries T3 information is sent to optical network device 06-2 module and processes, and is sent at last ONU PON mouth and is forwarded to up master clock.

S6, arriving optical network device 01-2 module from EPON inside downgoing time stamp message packet processes, message is recorded and arrives EPON local system time corresponding to 01-2 is T2, and time-stamping messages message and corresponding EPON local system time T 2 are preserved one to one.

S7, this downgoing time stamp message packet and corresponding T2 information are sent to optical network device 03-2 module and process, the 03-2 module also has the time bias function, with compensate this resume module time and from this module to message the actual time error that sends etc., by compensation so that the accuracy of the residence time that is corrected be improved.By calculating the actual residence time that obtains uplink message, then revise this time-stamping messages message, concrete correcting mode is with reference to above-described embodiment and preferred embodiment.

S8, the downgoing time that is corrected stamp message packet is sent to optical network device 04-2 module and processes, through being reduced into downgoing time stamp message packet reference format after the lift-off processing.

S9 is sent to optical network device 05-2 module finally by revising time-stamping messages message rear and that be stripped from, and it is upper from clockwork to be sent out ONU.

Obviously, those skilled in the art should be understood that, above-mentioned each module of the present invention or each step can realize with general calculation element, they can concentrate on the single calculation element, perhaps be distributed on the network that a plurality of calculation elements form, alternatively, they can be realized with the executable program code of calculation element, carried out by calculation element thereby they can be stored in the storage device, perhaps they are made into respectively each integrated circuit modules, perhaps a plurality of modules in them or step are made into the single integrated circuit module and realize.Like this, the present invention is not restricted to any specific hardware and software combination.

The above is the preferred embodiments of the present invention only, is not limited to the present invention, and for a person skilled in the art, the present invention can have various modifications and variations.Within the spirit and principles in the present invention all, any modification of doing, be equal to replacement, improvement etc., all should be included within protection scope of the present invention.

Claims

1. a time synchronizing method is characterized in that comprising the steps:

Receive time-stamping messages message for time synchronized by the receiving port in the EPON from master clock and the side from clock, and record receives the time of described time-stamping messages message;

Record sends time of described time-stamping messages message by the transmit port in the EPON, and wherein, the equipment time at described transmit port and described receiving port and place keeps synchronously;

According to the time of the time that receives described time-stamping messages message and the described time-stamping messages message of transmission, the temporal information that is used for time synchronized of carrying in the described time-stamping messages message is revised;

Send described time-stamping messages message by described transmit port to described master clock and the opposing party from clock.

2. method according to claim 1 is characterized in that, the time that record receives described time-stamping messages message comprises:

Record described time-stamping messages message and arrive time of described receiving port;

The time that arrives described receiving port is compensated according to the first make-up time and/or the second make-up time, wherein, described the first make-up time is that described time-stamping messages message arrives described receiving port and arrives time-delay between the corresponding physical port of described receiving port, and described the second make-up time is the processing time that receives described time-stamping messages message process;

The time that will obtain after will compensating the time that described time-stamping messages message arrives described receiving port, be recorded as the time that receives described time-stamping messages message.

3. method according to claim 1 and 2 is characterized in that, record comprised by the time that described transmit port sends described time-stamping messages message:

Record described time-stamping messages message and arrive time of described transmit port;

The time that arrives described transmit port is compensated according to the 3rd make-up time and/or the 4th make-up time, wherein, described the 3rd make-up time is the error that described time-stamping messages message arrives time and the actual time that sends of described transmit port, and described the 4th make-up time is for to the described processing time of revising for the temporal information of time synchronized;

The time that will obtain after will compensating the time that described time-stamping messages message arrives described transmit port, be recorded as the time that sends described time-stamping messages message by described transmit port.

4. method according to claim 1 is characterized in that, the time of the equipment at described transmit port and described receiving port and place keeps one of at least synchronously in the following manner:

The telecommunication standards group ITU-T of International Telecommunications Union G.984.3 AD2, the telecommunication standards group ITU-T of International Telecommunications Union G.987.3, IEEE802.1as.

5. method according to claim 1 is characterized in that, records the time that receives the time of described time-stamping messages message and send described time-stamping messages message by described transmit port by following time format:

Described time format comprises: be used to indicate the field on date, the field that is used to indicate hour field of minute second and is used to indicate nanosecond.

6. method according to claim 1 or 5, it is characterized in that, will receive the time of described time-stamping messages message and be recorded in the described time-stamping messages message by the time that described transmit port sends described time-stamping messages message by described receiving port.

7. time synchronizing device is characterized in that comprising:

Very first time stamp message sink module, the receiving port that is used for by EPON receives time-stamping messages message for time synchronized from master clock and the side from clock, and record receives the time of described time-stamping messages message;

The second time-stamping messages receiver module, be used for receiving the described time-stamping messages message from described very first time stamp message sink module, and record sends the time of described time-stamping messages message by the transmit port in the EPON, wherein, the equipment time at described transmit port and described receiving port and place keeps synchronously;

Correcting module is used for the time according to the time that receives described timestamp message and the described time-stamping messages message of transmission, and the temporal information that is used for time synchronized of carrying in the described time-stamping messages message is revised;

The time-stamping messages sending module is used for sending described time-stamping messages message by described transmit port to described master clock with from the opposing party of clock.

8. device according to claim 7 is characterized in that, described very first time stamp message sink module comprises:

The first record cell is used for recording the time that described time-stamping messages message arrives described receiving port;

The first compensating unit, be used for according to the first make-up time and/or the second make-up time the time that arrives described receiving port being compensated, wherein, described the first make-up time is that described time-stamping messages message arrives described receiving port and arrives time-delay between the corresponding physical port of described receiving port, and described the second make-up time is the processing time that receives described time-stamping messages message process;

The second record cell, is recorded as the time that receives described time-stamping messages message at the time that obtains after being used for compensating the time that described time-stamping messages message arrives described receiving port.

9. according to claim 7 or 8 described devices, it is characterized in that described the second time-stamping messages receiver module comprises:

The 3rd record cell is used for recording the time that described time-stamping messages message arrives described transmit port;

The second compensating unit, be used for according to the 3rd make-up time and/or the 4th make-up time the time that arrives described transmit port being compensated, wherein, described the 3rd make-up time is the error that described time-stamping messages message arrives time and the actual time that sends of described transmit port, and described the 4th make-up time is for to the described processing time of revising for the temporal information of time synchronized;

The 4th record cell, is recorded as the time that sends described time-stamping messages message by described transmit port at the time that obtains after being used for compensating the time that described time-stamping messages message arrives described transmit port.

10. time synchronizing system, comprise: clock equipment, from clockwork, optical line terminal OLT, optical network unit ONU, it is characterized in that, also comprise: each described device in the claim 7 to 9, wherein, described device is connected to described clock equipment and described between clockwork, and described clock equipment, described pass between clockwork, described OLT and described ONU are one of following:

Described clock equipment and describedly be independent of respectively described OLT and described ONU from clockwork;

Described clock equipment is positioned on the described OLT, describedly is independent of described OLT and described ONU from clockwork;

Described clock equipment is independent of described OLT and described ONU, describedly is positioned on the described ONU from clockwork;

Described clock equipment is positioned on the described OLT, describedly is positioned on the described ONU from clockwork.