CN101630988A - Method, device and system for transferring synchronous clock - Google Patents
Method, device and system for transferring synchronous clock Download PDFInfo
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- CN101630988A CN101630988A CN200810185854A CN200810185854A CN101630988A CN 101630988 A CN101630988 A CN 101630988A CN 200810185854 A CN200810185854 A CN 200810185854A CN 200810185854 A CN200810185854 A CN 200810185854A CN 101630988 A CN101630988 A CN 101630988A
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Abstract
The invention discloses a method, a device and a system for transferring a synchronous clock, and relates to the technical field of optical communication to solve the problem that a GPON network cannot transfer the synchronous clock in the prior art. The method for transferring the synchronous clock, which is provided by the embodiment of the invention, comprises the following steps that: determining an optimal synchronous clock by an optical line terminal; taking the optimal synchronous clock as reference to generate a GPON physical clock by the optical line terminal; acquiring the physical clock through the GPON by an optical network unit; and taking the physical clock as reference to generate a clock which is synchronous with the optimal synchronous clock by the optical network unit. The method, the device and the system are suitable for transferring the synchronous clock in the GPON network.
Description
The application is that the application number submitted on July 14th, 2008 is 200810132786.7, denomination of invention is divided an application for the application of " transmission method of synchronised clock, device and system ".
Technical field
The present invention relates to the optical communication technique field, relate in particular to a kind of transmission method, device and system of synchronised clock.
Background technology
GPON (Gigabit-Capable Passive Optical Network, gigabit passive optical network) technology is important techniques branch in PON (Passive Optical Network, the EPON) family.With other PON technology type seemingly, GPON also is a kind of passive light access technology that a little arrives the multidrop topology structure that adopts, comprise an OLT (Optical Line Terminals who is installed on console for centralized control, optical line terminal), a collection of ONU (the Optical Network Unit that is installed on customer site supportingly, optical network unit) and ODN (Optical Distribution Network, Optical Distribution Network) form.
At present, in the GPON network, mainly adopt TDM (Time Division Multiplex, time division multiplexing) circuit simulation mode to transmit the TDM business data flow, and transmit synchronised clock with this TDM business data flow.The TDM circuit simulation mainly is to use in packet network, and the TDM business datum is encapsulated with the circuit simulation heading, and the message after the encapsulation is PW (pseudo wire) message.When being used for the GPON network, usually the PW message is encapsulated into again G-PON Encapsulation Mode (GPON Encapsulation Mode, GEM) the middle transmission.The key technology of TDM circuit simulation is the self-adaptive recovery algorithm, and the detailed process of self-adaptive recovery algorithm application in the GPON network is:
TDM equipment sends to the TDM circuit of OLT with the TDM business data flow, and the TDM circuit carries out simulation process to this data flow earlier, obtains the PW message, then the PW message is encapsulated in the GEM frame; PW message in the described GEM frame is sent to ONU by the GPON network, and ONU obtains the PW message with the PW message decapsulation in this GEM frame, and with behind the temporary PW message of a buffer memory, it is sent.
Wherein, described TDM equipment is equipped with the first clock fs, and by the control of this clock, TDM equipment sends to business data flow in the TDM circuit of OLT; ONU equipment is equipped with second clock fd, and by the control of this clock, ONU equipment sends the PW message.
In realizing process of the present invention, the inventor finds that there are the following problems at least in the prior art:
Because the encapsulation speed of tdm traffic and PW message is different, small speed difference between the two could come out by concentrated expression after can being accumulated to a certain degree, and these differences can cause the bigger variation of data volume in the ONU buffer memory.And the data volume in second clock fd and the buffer memory has very big relation, and the bigger variation of data volume in the buffer memory will cause the bigger variation of fd, thereby causes fd that bigger shake and drift are arranged, and can not realize with the first clock fs synchronous.Therefore, transmitting when handling the back by the business data flow of ONU output, can not transmit synchronised clock simultaneously through the TDM circuit simulation.That is to say that traditional GPON network can not transmit synchronised clock.
Summary of the invention
Embodiments of the invention provide a kind of transmission method, device and system of synchronised clock, can transmit synchronised clock in the GPON network in high quality.
For achieving the above object, embodiments of the invention adopt following technical scheme:
A kind of transmission method of synchronised clock comprises:
Optical line terminal is determined a preferable synchronous clock;
Optical line terminal is the phy clock that benchmark produces GPON with described preferable synchronous clock;
Optical network unit obtains described phy clock by GPON;
Optical network unit is a benchmark with described phy clock, produces and the synchronous clock of described preferable synchronous clock.
A kind of optical line terminal comprises:
The clock determining unit is used for determining a preferable synchronous clock;
The phy clock generation unit, being used for described preferable synchronous clock is the phy clock that benchmark produces GPON.
A kind of optical network unit comprises:
The phy clock acquiring unit is used for obtaining by GPON the phy clock of the GPON that described optical line terminal produces;
Clock generating unit, the phy clock that is used for the GPON that gets access to described phy clock acquiring unit is a benchmark, produces and the synchronous clock of described preferable synchronous clock.
A kind of transmission system of synchronised clock comprises:
Optical line terminal is used for determining a preferable synchronous clock, is the phy clock that benchmark produces GPON with this preferable synchronous clock;
Optical network unit is used for obtaining the described phy clock that optical line terminal produces by GPON, is benchmark with described phy clock, produces and the synchronous clock of described preferable synchronous clock.
The transmission method of the synchronised clock that the embodiment of the invention provides, device and system, optical line terminal is determined a preferable synchronous clock, produce the phy clock of GPON by described preferable synchronous clock, optical network unit recovers described phy clock by GPON, and be benchmark with described phy clock, produce and the synchronous clock of described preferable synchronous clock.Compared with prior art, the present invention can realize that clock the whole network in GPON is synchronous in simple mode, can satisfy synchronised clock for shake, drift and frequency accuracy performance demands, and then transmit synchronised clock in high quality.
Description of drawings
The transmission method flow chart of the synchronised clock that Fig. 1 provides for the embodiment of the invention;
Fig. 2 is transmission method embodiment one flow chart of synchronised clock of the present invention;
Fig. 3 is transmission method embodiment two flow charts of synchronised clock of the present invention;
Fig. 4 is transmission method embodiment four flow charts of synchronised clock of the present invention;
Fig. 5 is transmission method embodiment six flow charts of synchronised clock of the present invention;
Fig. 6 is transmission method embodiment seven flow charts of synchronised clock of the present invention;
The optical line terminal structural representation that Fig. 7 provides for the embodiment of the invention;
The optical network unit structural representation that Fig. 8 provides for the embodiment of the invention;
The transmission system structural representation of the synchronised clock that Fig. 9 provides for the embodiment of the invention.
Embodiment
Transmit the not high problem of synchronization clock mass in the prior art in order to solve, embodiments of the invention provide a kind of transmission method, device and system of synchronised clock.
For the advantage that makes technical solution of the present invention is clearer, the present invention is elaborated below in conjunction with drawings and Examples.
Embodiments of the invention provide a kind of transmission method of synchronised clock, and this method can be transmitted synchronised clock in high quality.
As shown in Figure 1, described method comprises:
S101: optical line terminal is determined a preferable synchronous clock;
S102: optical line terminal is the phy clock that benchmark produces gigabit passive optical network (GPON) with described preferable synchronous clock;
S103: optical network unit obtains described phy clock by GPON;
S104: optical network unit is a benchmark with described phy clock, produces and the synchronous clock of described preferable synchronous clock.
The transmission method of the synchronised clock that the embodiment of the invention provides, optical line terminal is determined a preferable synchronous clock, produce the phy clock of GPON by described preferable synchronous clock, optical network unit recovers described phy clock by GPON, and be benchmark with described phy clock, produce and the synchronous clock of described preferable synchronous clock.Compared with prior art, the present invention can realize that clock the whole network in GPON is synchronous in simple mode, can satisfy synchronised clock for shake, drift and frequency accuracy performance demands, and then transmit synchronised clock in high quality.
Describe in detail below in conjunction with the transmission method of specific embodiment to described synchronised clock.
Wherein, described optical line terminal determines that the step of a preferable synchronous clock comprises:
Optical line terminal is chosen the best synchronised clock of one road quality information from building integrated timing supply BITS, E1 phy clock, internal clock source, SDH link, GPS link or other GPON networks, as preferable synchronous clock; Perhaps, optical line terminal is chosen one road synchronised clock according to the priority of setting.
In following all embodiment, OLT has a BITS synchronised clock mouth and two professional inputs of E1, and ONU has a BITS synchronised clock mouth and two professional outputs of E1.
Wherein, if BITS disposes when being 2Mbit/s, optical line terminal is imported the data flow of BITS simultaneously.
Embodiment one
In this embodiment, transmit two-way E1 business simultaneously, described two-way E1 business has been carried different synchronised clocks respectively when ONU exports.As shown in Figure 2, the specific implementation process of present embodiment is as follows:
The synchronised clock input module of S201:OLT is perhaps set according to the user according to synchronization clock mass information, and the input of selecting BITS or a certain road E1 is delivered to the synchronised clock processing module as the synchronised clock source;
S202:, produce the synchronous timing signal of OLT inside according to selected synchronised clock;
S203: according to selected synchronised clock, produce synchronous 8KHz and the 155.52MHzGPON phy clock of synchronised clock therewith, deliver to the GTC processing module of OLT;
S204: calculate the speed difference between two-way E1 business and the described synchronous timing signal;
S205: together with the E1 speed difference that calculates and synchronization clock mass information, deliver to the GEM package module, by the GEM package module this E1 speed difference, synchronization clock mass information and E1 business data flow are encapsulated in the GEM frame, and be sent to ONU, wherein, described synchronization clock mass information is optional content;
Wherein, the detailed process of described GEM encapsulation is: the form that G.984 information to be packaged defined according to ITU-T is encapsulated in the GEM frame, comprising the GEM frame head of 5 bytes, the synchronizing quality information of 1 byte, the speed difference of 1 byte and the E1 data flow of variable-length.
Wherein, on the basis of above-mentioned encapsulation process, can reduce the length of synchronization clock mass information and speed difference, represent synchronization clock mass information and speed difference with 4 bits respectively, can reduce the frame length of GEM, improve bandwidth availability ratio.
The synchronised clock processing module of S206:ONU is recovered 8KHz and 155.52MHzGPON phy clock from the GTC frame that receives;
Wherein, described 8KHz clock recovery process is: ONU searches for the GTC frame head from the data flow that receives, and when searching out GTC frame head 0xB6AB31E0, sends a marking signal, the GTC frame that this marking signal and OLT send is frequency together, thereby obtains the GPON phy clock of 8KHz.
The GTC frame head is defined as the 0xB6AB31E0 of 4 bytes, the 125us GTC frame period that G.984.3 the GTC frame frequency of 8KHz defines from ITU-T in G.984.3 at ITU-T.
Described 155.52MHz clock recovery process is: the light signal that ONU receives, the process optical module is delivered to CDR (clock and data recovery after doing light-electricity conversion, clock and data recovery) device, this CDR device is isolated clock and data from serial data stream, and do and go here and there and conversion at 1: 16, obtain the 155.52MHz line clock.
155.52MHz be by the parallel-to-serial converter spare that is positioned on the OLT, and be positioned at deserializer spare decision on the ONU, be specifically as follows 1/2/4/8/16/32nd or other multiple of 2.48832G line speed.Usually with 1: 16,1: 8,1: 4,, the 311Hz clock is done the GPON phy clock that 2 frequency divisions can get 155.52MHz if, the clock of 311MHz will be recovered with 1: 8.
S207: according to described GPON phy clock, produce the synchronous ONU internal timing signal of GPON phy clock therewith, and the clock synchronous with described preferable synchronous clock;
S208: separate the GEM encapsulation, obtain the speed difference and the synchronization clock mass information of the two-way E1 business data flow of OLT calculating;
S209:, calculate the original input rate of two-way E1 business data flow at the E1 of OLT line interface place according to the speed difference of described two-way E1 business data flow and the synchronous timing signal of ONU inside;
S210: according to original input rate of described two-way and the inner synchronous timing signal of ONU, the synchronous output phy clock of input phy clock of generation and described two-way E1 business data flow is exported two-way E1 business data flow respectively respectively;
The synchronised clock output module of S211:ONU from the output phy clock of above-mentioned two-way E1 business or with the synchronous clock of described preferable synchronous clock select one the tunnel, and determine whether to add synchronization clock mass information, from the synchronised clock mouth output of ONU.
In the present embodiment, transmit the business data flow that two-way has different clocks simultaneously, by difference modes, with the output of two-way business data flow, wherein, the output phy clock of described two-way business data flow is synchronous with its input phy clock respectively.Compared with prior art, the present invention can realize the transmission of synchronised clock in GPON in simple mode, and, optical line terminal can be chosen preferable synchronous clock from multiple synchronised clock source, do not need to set up separately the synchronised clock distribution networks, business can satisfy synchronised clock for shake, drift and frequency accuracy performance demands, and then transmit synchronised clock in high quality by identical network delivery with clock.
Embodiment two:
In this embodiment, transmit two-way E1 business simultaneously, described two-way E1 business has been carried different synchronised clocks respectively when ONU exports.Different with embodiment one is that present embodiment directly encapsulates and decapsulation the original input rate of E1, and does not calculate the speed difference between E1 and the described synchronous timing signal.As shown in Figure 3, the specific implementation process of present embodiment is as follows:
S301-S303: S201-S203 is identical with step;
S304: together with the original input rate of described E1 and synchronization clock mass information, deliver to the GEM package module, be encapsulated in the GEM frame by original input rate, synchronization clock mass information and the E1 business data flow of GEM package module this E1, be sent to ONU, wherein, described synchronization clock mass information is optional content;
Wherein, identical among the process of described GEM encapsulation and the embodiment one, repeat no more herein.
The synchronised clock processing module of S305:ONU is recovered described GPON phy clock from the GTC frame that receives;
S306: according to described GPON phy clock, produce the synchronous ONU internal timing signal of GPON phy clock therewith, and the clock synchronous with described preferable synchronous clock;
S307: separate the GEM encapsulation, obtain the original input rate and the synchronization clock mass information of the two-way E1 business data flow of OLT calculating;
S308: according to original input rate of described two-way and the inner synchronous timing signal of ONU, the synchronous output phy clock of input phy clock of generation and described two-way E1 business data flow is exported two-way E1 business data flow respectively respectively;
The synchronised clock output module of S309:ONU from the output phy clock of above-mentioned two-way E1 business or with the synchronous clock of described preferable synchronous clock select one the tunnel, and determine whether to add synchronization clock mass information, from the synchronised clock mouth output of ONU.
In the present embodiment, transmit the business data flow that two-way has different clocks simultaneously, encapsulate and decapsulation by input rate the two-way business data flow, the two-way business data flow is exported, wherein, the output phy clock of described two-way business data flow is synchronous with its input phy clock respectively.Compared with prior art, the present invention can realize the transmission of synchronised clock in GPON in simple mode, and, optical line terminal can be chosen preferable synchronous clock from multiple synchronised clock source, do not need to set up separately the synchronised clock distribution networks, business can satisfy synchronised clock for shake, drift and frequency accuracy performance demands, and then transmit synchronised clock in high quality by identical network delivery with clock.
Embodiment three
In this embodiment, the GPON network transmits two-way E1 business simultaneously, and described two-way E1 business has been carried identical synchronised clock when ONU exports.The specific implementation process of present embodiment is identical with embodiment one described implementation procedure, does not repeat them here.Wherein, among the described step S204 speed difference between the professional and described synchronous timing signal of two-way E1 constant be zero.
Certainly, present embodiment also can be similar with embodiment two, and directly the original input rate to E1 encapsulates and decapsulation, and do not calculate the speed difference between E1 and the described synchronous timing signal, the specific implementation process does not repeat them here with reference to embodiment one and embodiment two.
Embodiment four
In this embodiment, transmit the synchronization clock mass information that one road E1 carries, as shown in Figure 4, the specific implementation process of present embodiment is as follows:
The synchronised clock input module of S401:OLT selects the input of one road E1 as the synchronised clock source, delivers to the synchronised clock processing module;
S402: according to selected synchronised clock, the synchronised clock processing module produces the synchronous timing signal of OLT inside;
S403: according to described synchronous timing signal, produce the synchronous GPON phy clock of synchronous timing signal therewith, deliver to the GTC processing module of OLT;
S404: calculate the speed difference between described E1 business and the described synchronous timing signal;
S405: together with the E1 speed difference that calculates and synchronization clock mass information, deliver to the GEM package module, by the GEM package module this E1 speed difference, synchronization clock mass information and E1 business data flow are encapsulated in the GEM frame, and be sent to ONU, wherein, described synchronization clock mass information is optional content;
The synchronised clock processing module of S406:ONU is recovered described GPON phy clock from the GTC frame that receives;
S407: according to described GPON phy clock, produce the synchronous ONU internal timing signal of GPON phy clock therewith, and the clock synchronous with described preferable synchronous clock;
S408: separate the GEM encapsulation, obtain the speed difference and the synchronization clock mass information of the E1 business data flow of OLT calculating;
S409:, calculate the original input rate of E1 business data flow at the E1 of OLT line interface place according to the speed difference of described E1 business data flow and the synchronous timing signal of ONU inside;
S410: according to described original input rate and the inner synchronous timing signal of ONU, the synchronous output phy clock of input phy clock of generation and described E1 business data flow, output E1 business data flow;
The synchronised clock output module of S411:ONU from the output phy clock of above-mentioned E1 business or with the synchronous clock of described preferable synchronous clock select one the tunnel, and determine whether to add synchronization clock mass information, from the synchronised clock mouth output of ONU.
Certainly, present embodiment also can be directly encapsulates and decapsulation the original input rate of E1, and does not calculate the speed difference between E1 and the described synchronous timing signal, and the specific implementation process does not repeat them here with reference to embodiment two.
In the present embodiment, transmit one road business data flow, by difference modes, with described business data flow output, wherein, the output phy clock of described business data flow and its input phy clock are synchronous.Compared with prior art, the present invention can realize the transmission of synchronised clock in GPON in simple mode, and, optical line terminal can be chosen preferable synchronous clock from multiple synchronised clock source, do not need to set up separately the synchronised clock distribution networks, business can satisfy synchronised clock for shake, drift and frequency accuracy performance demands, and then transmit synchronised clock in high quality by identical network delivery with clock.
Embodiment five
In this embodiment, transmit two-way E1 business simultaneously, described two-way E1 business has been carried different synchronised clocks respectively when ONU exports, export the synchronised clock that one road E1 carries from the synchronised clock mouth of ONU.The specific implementation process of present embodiment is identical with embodiment one described implementation procedure, does not repeat them here.Wherein, among the described step S211, the synchronised clock that the synchronised clock output module of ONU selects one road E1 business to carry is from the synchronised clock mouth output of ONU.
Certainly, present embodiment also can be directly encapsulates and decapsulation the original input rate of E1, and does not calculate the speed difference between E1 and the described synchronous timing signal, and the specific implementation process does not repeat them here with reference to embodiment two.
Embodiment six
In this embodiment, transmit the BITS synchronised clock of the 2.048MHZ of OLT input and export, do not comprise effective business data flow to the synchronised clock mouth of ONU.As shown in Figure 5, the specific implementation process of present embodiment is as follows:
The synchronised clock input module of S501:OLT selects the synchronised clock mouth of BITS to deliver to the synchronised clock processing module as the synchronised clock source;
S502: according to selected synchronised clock, the synchronised clock processing module produces the synchronous GPON phy clock of synchronised clock therewith, delivers to the GTC processing module of OLT;
The synchronised clock processing module of S503:ONU is recovered described GPON phy clock from the GTC frame that receives;
S504:, produce the synchronised clock of the synchronous 2.048MHZ of GPON phy clock therewith according to described GPON phy clock;
S505: select of the synchronised clock mouth output of this 2.048MHZ synchronised clock from ONU.
In the present embodiment, transmit the synchronised clock mouth output of BITS synchronised clock to ONU, do not comprise effective business data flow, ONU directly produces the output phy clock by the phy clock of the GPON that gets access to.Compared with prior art, the present invention can realize that clock the whole network in GPON is synchronous in simple mode, can satisfy synchronised clock for shake, drift and frequency accuracy performance demands, and then transmit synchronised clock in high quality.
Embodiment seven
In this embodiment, transmit the BITS synchronised clock of the 2.048Mbit/s of OLT input and export, at this moment, need to transmit the 2.048Mbit/s data flow of BITS output to the synchronised clock mouth of ONU.As shown in Figure 6, the specific implementation process of present embodiment is as follows:
The synchronised clock input module of S601:OLT selects the synchronised clock mouth of BITS to deliver to the synchronised clock processing module as the synchronised clock source;
S602: according to selected synchronised clock, the synchronised clock processing module produces the synchronous GPON phy clock of synchronised clock therewith, delivers to the GTC processing module of OLT;
The synchronised clock processing module of S603:ONU is recovered described GPON phy clock from the GTC frame that receives;
S604: the synchronised clock processing module is carried out the GEM encapsulation with the 2.048Mbit/s data flow of BITS input, sends to ONU by the GPON network, wherein, comprises the quality information of synchronised clock in the data flow of described BITS;
S605:, produce the synchronised clock of the synchronous 2.048Mbit/s of GPON phy clock therewith according to described GPON phy clock;
The synchronised clock processing module of S606:ONU is carried out decapsulation with described data flow, obtains the BITS input traffic of OLT input, delivers to the synchronised clock output module of ONU and exports.
Thereby, utilize the transmission method of embodiments of the invention synchronised clock, can satisfy synchronised clock for shake, drift and frequency accuracy performance demands, in the GPON network, transmit synchronised clock in high quality.
Embodiments of the invention also provide a kind of optical line terminal, and this optical line terminal can transmit synchronised clock in high quality.
As shown in Figure 7, described optical line terminal comprises:
Phy clock generation unit 702, the preferable synchronous clock that is used for determining with described clock determining unit 701 is the phy clock that benchmark produces GPON.
The optical line terminal that the embodiment of the invention provides, at first determine a preferable synchronous clock, produce the phy clock of GPON by described preferable synchronous clock, recover described phy clock by optical network unit by GPON, and be benchmark with described phy clock, produce and the synchronous clock of described preferable synchronous clock.Compared with prior art, the present invention can realize that clock the whole network in GPON is synchronous in simple mode, can satisfy synchronised clock for shake, drift and frequency accuracy performance demands, and then transmit synchronised clock in high quality.
As shown in Figure 7, described optical line terminal also comprises:
Receiving element 703 is used to receive business data flow;
The first timing signal for generating unit 704, being used for described preferable synchronous clock is that benchmark produces first timing signal;
Speed difference computing unit 705 is used to calculate the speed difference between first timing signal of business data flow that described receiving element 703 receives and the described first timing signal for generating unit, 704 generations;
Thereby, utilize the embodiments of the invention optical line terminal, can satisfy synchronised clock for shake, drift and frequency accuracy performance demands, and then in the GPON network, transmit synchronised clock in high quality.
Embodiments of the invention also provide a kind of optical network unit, and this optical network unit can transmit synchronised clock in high quality.
As shown in Figure 8, described optical network unit comprises:
Phy clock acquiring unit 801 is used for obtaining by GPON the phy clock of the GPON that described optical line terminal produces;
The optical network unit that the embodiment of the invention provides, optical network unit recovers the phy clock of the GPON that optical line terminal produces by GPON, and is benchmark with described phy clock, produces and the synchronous clock of described preferable synchronous clock.Compared with prior art, the present invention can realize that clock the whole network in GPON is synchronous in simple mode, can satisfy synchronised clock for shake, drift and frequency accuracy performance demands, and then transmit synchronised clock in high quality.
As shown in Figure 8, described optical network unit also comprises:
Second timing signal generation unit 803, the phy clock that is used for the GPON that gets access to described phy clock acquiring unit 801 is a benchmark, produces second timing signal;
As shown in Figure 8, described optical network unit also comprises:
Thereby, utilize the embodiments of the invention optical network unit, can satisfy synchronised clock for shake, drift and frequency accuracy performance demands, and then in the GPON network, transmit synchronised clock in high quality.
Embodiments of the invention also provide a kind of transmission system of synchronised clock, and this system can transmit synchronised clock in high quality.
As shown in Figure 9, described system comprises:
The transmission system of the synchronised clock that the embodiment of the invention provides, optical line terminal is determined a preferable synchronous clock, produce the phy clock of GPON by described preferable synchronous clock, optical network unit recovers described phy clock by GPON, and be benchmark with described phy clock, produce and the synchronous clock of described preferable synchronous clock.Compared with prior art, the present invention can realize that clock the whole network in GPON is synchronous in simple mode, can satisfy synchronised clock for shake, drift and frequency accuracy performance demands, and then transmit synchronised clock in high quality.
Wherein, when while during the business transferring data flow, described optical line terminal 901, also being used for described preferable synchronous clock is that benchmark produces first timing signal;
Described optical network unit 902, also being used for described phy clock is benchmark, produces second timing signal.
Thereby, utilize the transmission system of embodiments of the invention synchronised clock, can satisfy synchronised clock for shake, drift and frequency accuracy performance demands, and then in the GPON network, transmit synchronised clock in high quality.
The above; it only is the embodiment of the embodiment of the invention; but the protection range of the embodiment of the invention is not limited thereto; anyly be familiar with those skilled in the art in the technical scope that the present invention discloses; the variation that can expect easily or replacement all should be encompassed within protection scope of the present invention.Therefore, the protection range of the embodiment of the invention should be as the criterion with the protection range of claim.
Claims (18)
1, a kind of transmission method of synchronised clock is characterized in that, comprising:
Optical line terminal is determined a preferable synchronous clock;
Optical line terminal is the phy clock that benchmark produces gigabit passive optical network (GPON) with described preferable synchronous clock;
Optical network unit obtains described phy clock by GPON;
Optical network unit is a benchmark with described phy clock, produces and the synchronous clock of described preferable synchronous clock.
2, the transmission method of synchronised clock according to claim 1 is characterized in that, described optical line terminal determines that the step of a preferable synchronous clock comprises:
Optical line terminal is chosen the best synchronised clock of one road quality information from building integrated timing supply BITS, E1 phy clock, internal clock source, SDH link, GPS link or other GPON networks, as preferable synchronous clock; Or
Optical line terminal is chosen one road synchronised clock according to the priority of setting.
3, the transmission method of synchronised clock according to claim 1 is characterized in that, determines at described optical line terminal also to comprise before the step of a preferable synchronous clock:
Optical line terminal receives business data flow.
4, the transmission method of synchronised clock according to claim 3 is characterized in that, before described optical network unit obtains the step of described phy clock by GPON, also comprises:
Optical line terminal is that benchmark produces first timing signal with described preferable synchronous clock;
Calculate the speed difference between described business data flow and described first timing signal;
Described speed difference and business data flow are carried out being sent to optical network unit after the GEM encapsulation.
5, the transmission method of synchronised clock according to claim 4 is characterized in that, after described optical network unit obtains the step of described phy clock by GPON, also comprises:
Optical network unit is a benchmark with described phy clock, produces second timing signal;
Optical network unit carries out decapsulation to described speed difference and business data flow through the GEM encapsulation;
Optical network unit calculates the original input rate of described business data flow at the optical line terminal place according to described speed difference and second timing signal;
Optical network unit is according to described original input rate and second timing signal, and the synchronous output phy clock of input phy clock of generation and described business data flow is exported described business data flow.
6, the transmission method of synchronised clock according to claim 3 is characterized in that, before described optical network unit obtains the step of described phy clock by GPON, also comprises:
The original input rate of business data flow and described business data flow is carried out the GEM encapsulation be sent to optical network unit.
7, the transmission method of synchronised clock according to claim 6 is characterized in that, after described optical network unit obtains the step of described phy clock by GPON, also comprises:
Optical network unit carries out decapsulation to described through the business data flow of GEM encapsulation and the original input rate of described business data flow;
Optical network unit is according to described original input rate and second timing signal, and the synchronous output phy clock of input phy clock of generation and described business data flow is exported described business data flow.
8, according to the transmission method of claim 5 or 7 described synchronised clocks, it is characterized in that, also comprise:
From with the output phy clock of synchronous clock of described preferable synchronous clock and business data flow select one the tunnel, by the synchronised clock mouth output of optical network unit.
9, the transmission method of synchronised clock according to claim 1, it is characterized in that, when the determined preferable synchronous clock of optical line terminal is the BITS synchronised clock of 2Mbit/s, before described optical network unit obtains the step of described phy clock by GPON, also comprise:
The data flow of input BITS;
Optical line terminal carries out the GEM encapsulation with the data flow of described BITS, sends to optical network unit by GPON, comprises the quality information of preferable synchronous clock in the data flow of described BITS.
10, the transmission method of synchronised clock according to claim 9 is characterized in that, after described optical network unit obtains the step of described phy clock by GPON, also comprises:
Optical network unit carries out decapsulation to the data flow of described BITS;
Optical network unit is exported the data flow of described BITS.
11, the transmission method of synchronised clock according to claim 10 is characterized in that, also comprises:
Clock that will be synchronous with the BITS synchronised clock of described 2Mbit/s is by the synchronised clock mouth output of optical network unit.
12, a kind of optical line terminal is characterized in that, comprising:
The clock determining unit is used for determining a preferable synchronous clock;
The phy clock generation unit, being used for described preferable synchronous clock is the phy clock that benchmark produces GPON.
13, optical line terminal according to claim 12 is characterized in that, also comprises:
Receiving element is used to receive business data flow;
The first timing signal for generating unit, being used for described preferable synchronous clock is that benchmark produces first timing signal;
The speed difference computing unit is used to calculate the speed difference between first timing signal of business data flow that described receiving element receives and the generation of the described first timing signal for generating unit;
Encapsulation unit is used for described business data flow, speed difference or speed are carried out being sent to optical network unit after the GEM encapsulation.
14, a kind of optical network unit is characterized in that, comprising:
The phy clock acquiring unit is used for obtaining by GPON the phy clock of the GPON that described optical line terminal produces;
Clock generating unit, the phy clock that is used for the GPON that gets access to described phy clock acquiring unit is a benchmark, produces and the synchronous clock of described preferable synchronous clock.
15, optical network unit according to claim 14 is characterized in that, also comprises:
The second timing signal generation unit, the phy clock that is used for the GPON that gets access to described phy clock acquiring unit is a benchmark, produces second timing signal;
Decapsulation unit is used for described business data flow, speed difference or speed through the GEM encapsulation is carried out decapsulation;
The rate calculations unit is used for the second timing signal according to described speed difference and the generation of second timing signal generation unit, the original input rate of computing service data flow;
Professional output unit is used for according to described original input rate and described second timing signal, and the synchronous output phy clock of input phy clock of generation and described business data flow is exported described business data flow.
16, optical network unit according to claim 15 is characterized in that, also comprises:
The clock output unit is used for selecting one the tunnel from the output phy clock of synchronous clock of described preferable synchronous clock and business data flow, by the synchronised clock mouth output of optical network unit.
17, a kind of transmission system of synchronised clock is characterized in that, comprising:
Optical line terminal is used for determining a preferable synchronous clock, is the phy clock that benchmark produces GPON with this preferable synchronous clock;
Optical network unit is used for obtaining the described phy clock that optical line terminal produces by GPON, is benchmark with described phy clock, produces and the synchronous clock of described preferable synchronous clock.
18, the transmission system of synchronised clock according to claim 17 is characterized in that,
Described optical line terminal, also being used for described preferable synchronous clock is that benchmark produces first timing signal;
Described optical network unit, also being used for described phy clock is benchmark, produces second timing signal.
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| CN200810185854A CN101630988A (en) | 2008-07-14 | 2008-07-14 | Method, device and system for transferring synchronous clock |
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| CN200810185854A CN101630988A (en) | 2008-07-14 | 2008-07-14 | Method, device and system for transferring synchronous clock |
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| CN2008101327867A Division CN101631014B (en) | 2008-07-14 | 2008-07-14 | Method, device and system for transmitting synchronous clock |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105634642A (en) * | 2016-01-06 | 2016-06-01 | 烽火通信科技股份有限公司 | Clock synchronization method and device for EPON (Ethernet Passive Optical Network) system |
| CN107330231A (en) * | 2017-08-10 | 2017-11-07 | 国网天津市电力公司 | Control system Real Time Simulation Frame design method based on FPGA |
-
2008
- 2008-07-14 CN CN200810185854A patent/CN101630988A/en active Pending
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105634642A (en) * | 2016-01-06 | 2016-06-01 | 烽火通信科技股份有限公司 | Clock synchronization method and device for EPON (Ethernet Passive Optical Network) system |
| CN107330231A (en) * | 2017-08-10 | 2017-11-07 | 国网天津市电力公司 | Control system Real Time Simulation Frame design method based on FPGA |
| CN107330231B (en) * | 2017-08-10 | 2020-07-07 | 国网天津市电力公司 | Control system real-time simulation framework design method based on FPGA |
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