CN101631014B - Method, device and system for transmitting synchronous clock - Google Patents
Method, device and system for transmitting synchronous clock Download PDFInfo
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- CN101631014B CN101631014B CN2008101327867A CN200810132786A CN101631014B CN 101631014 B CN101631014 B CN 101631014B CN 2008101327867 A CN2008101327867 A CN 2008101327867A CN 200810132786 A CN200810132786 A CN 200810132786A CN 101631014 B CN101631014 B CN 101631014B
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04Q—SELECTING
- H04Q11/00—Selecting arrangements for multiplex systems
- H04Q11/0001—Selecting arrangements for multiplex systems using optical switching
- H04Q11/0062—Network aspects
- H04Q11/0067—Provisions for optical access or distribution networks, e.g. Gigabit Ethernet Passive Optical Network (GE-PON), ATM-based Passive Optical Network (A-PON), PON-Ring
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04J—MULTIPLEX COMMUNICATION
- H04J3/00—Time-division multiplex systems
- H04J3/02—Details
- H04J3/06—Synchronising arrangements
- H04J3/0635—Clock or time synchronisation in a network
- H04J3/0638—Clock or time synchronisation among nodes; Internode synchronisation
- H04J3/0652—Synchronisation among time division multiple access [TDMA] nodes, e.g. time triggered protocol [TTP]
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04Q—SELECTING
- H04Q11/00—Selecting arrangements for multiplex systems
- H04Q11/0001—Selecting arrangements for multiplex systems using optical switching
- H04Q11/0062—Network aspects
- H04Q2011/0079—Operation or maintenance aspects
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Abstract
The invention discloses a method, a device and system for transmitting a synchronous clock, relates to the technical field of optical communication, and is invented to solve the problem that a GPON network cannot transmit the synchronous clock in the prior art. The method for transmitting the synchronous clock comprises that: an optical line terminal determines a preferable synchronous clock; the optical line terminal generates a GPON physical clock by taking the preferable synchronous clock as reference; an optical network unit acquires the physical clock through the GPON; and the optical network unit generates a clock synchronous with the preferable synchronous clock by taking the physical clock as reference. The method, the device and the system are suitable for transmitting the synchronous clock in the GPON network.
Description
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 (Optical Network Unit, optical network unit) and the ODN (Optical Distribution Network, Optical Distribution Network) that is installed on customer site forms supportingly.
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 in packet network, to use, 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 G-PON Encapsulation Mode (GPON Encapsulation Mode, GEM) the middle transmission again.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 said GEM frame is sent to ONU through 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, said TDM equipment is equipped with the first clock fs, and through 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 through the control of this clock, ONU equipment sends the PW message.
In realizing process of the present invention, the inventor finds to exist at least in the prior art following problem:
Because the encapsulation speed of tdm traffic and PW message is different, small speed difference between the two, can be accumulated to a certain degree after the ability concentrated expression come out, 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 G PON 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 in the GPON network, transmit synchronised clock 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 receives business data flow;
Optical line terminal is confirmed a preferable synchronous clock;
Optical line terminal is the phy clock that benchmark produces GPON with said preferable synchronous clock;
Optical line terminal is that benchmark produces first timing signal with said preferable synchronous clock, calculates the speed difference between said business data flow and said first timing signal, and said speed difference and business data flow are carried out being sent to optical network unit after the GEM encapsulation; Perhaps, optical line terminal carries out GEM encapsulation with the original input rate of business data flow and said business data flow and is sent to optical network unit;
Optical network unit obtains said phy clock through GPON;
Optical network unit is a benchmark with said phy clock, produces and said preferable synchronous clock clock synchronized.
A kind of optical line terminal comprises:
Receiving element is used to receive business data flow;
Clock is confirmed the unit, is used for confirming a preferable synchronous clock;
The phy clock generation unit, being used for said preferable synchronous clock is the phy clock that benchmark produces GPON;
The first timing signal for generating unit, being used for said 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 said receiving element receives and the generation of the said first timing signal for generating unit;
Encapsulation unit is used for said business data flow, speed difference or speed are carried out being sent to optical network unit after the GEM encapsulation.
A kind of optical network unit comprises:
The phy clock acquiring unit is used for obtaining through GPON the phy clock of the GPON that said optical line terminal produces;
The second timing signal generation unit, the phy clock of the GPON that is used for getting access to said phy clock acquiring unit is a benchmark, produces second timing signal;
Decapsulation unit is used for said 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 said 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 said original input rate and said second timing signal, and the synchronous output phy clock of input phy clock of generation and said business data flow is exported said business data flow;
Clock generating unit, the phy clock of the GPON that is used for getting access to said phy clock acquiring unit is a benchmark, produces and said preferable synchronous clock clock synchronized.
A kind of transmission system of synchronised clock comprises:
Optical line terminal is used for confirming a preferable synchronous clock, is the phy clock that benchmark produces GPON with this preferable synchronous clock; Be used for that also the original input rate of business data flow and said business data flow is carried out the GEM encapsulation and be sent to optical network unit; Perhaps, also being used for said preferable synchronous clock is that benchmark produces first timing signal, calculates the speed difference between said business data flow and said first timing signal, and said speed difference and business data flow are carried out being sent to optical network unit after the GEM encapsulation;
Optical network unit; Being used for obtaining the said phy clock that optical line terminal produces through GPON, is benchmark with said phy clock, produces second timing signal; Said business data flow, speed difference or speed through the GEM encapsulation is carried out decapsulation; According to said speed difference and second timing signal, the original input rate of computing service data flow is according to said original input rate and said second timing signal; The synchronous output phy clock of input phy clock of generation and said business data flow is exported said business data flow.
The transmission method of the synchronised clock that the embodiment of the invention provides, device and system; Optical line terminal is confirmed a preferable synchronous clock; Produce the phy clock of GPON by said preferable synchronous clock; Optical network unit recovers said phy clock through GPON, and is benchmark with said phy clock, produces and said preferable synchronous clock clock synchronized.Compared with prior art, the present invention can realize that clock the whole network in GPON is synchronous with 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 scheme of the present invention is clearer, the present invention is elaborated below in conjunction with accompanying drawing and embodiment.
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, said method comprises:
S101: optical line terminal is confirmed a preferable synchronous clock;
S102: optical line terminal is the phy clock that benchmark produces gigabit passive optical network (GPON) with said preferable synchronous clock;
S103: optical network unit obtains said phy clock through GPON;
S104: optical network unit is a benchmark with said phy clock, produces and said preferable synchronous clock clock synchronized.
The transmission method of the synchronised clock that the embodiment of the invention provides; Optical line terminal is confirmed a preferable synchronous clock; Produce the phy clock of GPON by said preferable synchronous clock; Optical network unit recovers said phy clock through GPON, and is benchmark with said phy clock, produces and said preferable synchronous clock clock synchronized.Compared with prior art, the present invention can realize that clock the whole network in GPON is synchronous with 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 said synchronised clock.
Wherein, said optical line terminal confirms 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, it is professional to transmit two-way E1 simultaneously, and said two-way E1 business has been carried the different synchronization clock respectively when ONU exports.As shown in Figure 2, the concrete implementation procedure of present embodiment is following:
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 inner synchronous timing signal of OLT 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 said 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, said synchronization clock mass information is optional content;
Wherein, The detailed process of said 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, Said 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, sees a marking signal off; 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.
Said 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 does and go here and there and conversion at 1: 16, obtains 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, specifically can be 1/2/4/8/16/32nd or other multiple of 2.48832G line speed.Usually with 1: 16,1: 8,1: 4, if,, the 311Hz clock is done the GPON phy clock that 2 frequency divisions can get 155.52MHz with the clock that recovers 311MHz with 1: 8.
S207: according to said GPON phy clock, produce the synchronous ONU internal timing signal of GPON phy clock therewith, and with said preferable synchronous clock clock synchronized;
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: speed difference and the inner synchronous timing signal of ONU according to said two-way E1 business data flow calculate the original input rate of two-way E1 business data flow at the E1 of OLT line interface place;
S210: according to original input rate of said two-way and the inner synchronous timing signal of ONU, the synchronous output phy clock of input phy clock of generation and said two-way E1 business data flow is exported two-way E1 business data flow respectively respectively;
The synchronised clock output module of S211:ONU perhaps with the said preferable synchronous clock clock synchronized selects one the tunnel from the professional output phy clock of above-mentioned two-way E1, and determines 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, through difference modes, with the output of two-way business data flow, wherein, the output phy clock of said 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 with 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 through identical network delivery with clock.
Embodiment two:
In this embodiment, it is professional to transmit two-way E1 simultaneously, and said two-way E1 business has been carried the different synchronization clock 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 said synchronous timing signal.As shown in Figure 3, the concrete implementation procedure of present embodiment is following:
S301-S303: S201-S203 is identical with step;
S304: together with the original input rate of said 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, said synchronization clock mass information is optional content;
Wherein, identical among the process of said GEM encapsulation and the embodiment one, repeat no more here.
The synchronised clock processing module of S305:ONU is recovered said GPON phy clock from the GTC frame that receives;
S306: according to said GPON phy clock, produce the synchronous ONU internal timing signal of GPON phy clock therewith, and with said preferable synchronous clock clock synchronized;
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 said two-way and the inner synchronous timing signal of ONU, the synchronous output phy clock of input phy clock of generation and said two-way E1 business data flow is exported two-way E1 business data flow respectively respectively;
The synchronised clock output module of S309:ONU perhaps with the said preferable synchronous clock clock synchronized selects one the tunnel from the professional output phy clock of above-mentioned two-way E1, and determines 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 through input rate the two-way business data flow; With the output of two-way business data flow, wherein, the output phy clock of said 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 with 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 through identical network delivery with clock.
Embodiment three
In this embodiment, it is professional that the GPON network transmits two-way E1 simultaneously, and said two-way E1 business has been carried identical synchronised clock when ONU exports.The concrete implementation procedure of present embodiment is identical with embodiment one described implementation procedure, repeats no more at this.Wherein, among the said step S204 speed difference between the professional and said 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 does not calculate the speed difference between E1 and the said synchronous timing signal; Concrete implementation procedure repeats no more at this 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 concrete implementation procedure of present embodiment is following:
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 inner synchronous timing signal of OLT;
S403: according to said 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 said E1 business and the said 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, said synchronization clock mass information is optional content;
The synchronised clock processing module of S406:ONU is recovered said GPON phy clock from the GTC frame that receives;
S407: according to said GPON phy clock, produce the synchronous ONU internal timing signal of GPON phy clock therewith, and with said preferable synchronous clock clock synchronized;
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: speed difference and the inner synchronous timing signal of ONU according to said E1 business data flow calculate the original input rate of E1 business data flow at the E1 of OLT line interface place;
S410: according to said original input rate and the inner synchronous timing signal of ONU, the synchronous output phy clock of input phy clock of generation and said E1 business data flow, output E1 business data flow;
The synchronised clock output module of S411:ONU perhaps with the said preferable synchronous clock clock synchronized selects one the tunnel from the professional output phy clock of above-mentioned E1, and determines 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 said synchronous timing signal, and concrete implementation procedure repeats no more at this with reference to embodiment two.
In the present embodiment, transmit one road business data flow, through difference modes, with said business data flow output, wherein, the output phy clock of said 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 with 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 through identical network delivery with clock.
Embodiment five
In this embodiment, it is professional to transmit two-way E1 simultaneously, and said two-way E1 business has been carried the different synchronization clock respectively when ONU exports, export the synchronised clock that one road E1 carries from the synchronised clock mouth of ONU.The concrete implementation procedure of present embodiment is identical with embodiment one described implementation procedure, repeats no more at this.Wherein, among the said 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 said synchronous timing signal, and concrete implementation procedure repeats no more at this 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 concrete implementation procedure of present embodiment is following:
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 said 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 said 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 with 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 concrete implementation procedure of present embodiment is following:
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 said 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 through the GPON network, wherein, comprises the quality information of synchronised clock in the data flow of said BITS;
S605:, produce the synchronised clock of the synchronous 2.048Mbit/s of GPON phy clock therewith according to said GPON phy clock;
The synchronised clock processing module of S606:ONU is carried out decapsulation with said 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, said optical line terminal comprises:
Clock is confirmed unit 701, is used for confirming a preferable synchronous clock;
Phy clock generation unit 702 is used for confirming that with said clock the preferable synchronous clock that unit 701 is confirmed is the phy clock that benchmark produces GPON.
The optical line terminal that the embodiment of the invention provides; At first confirm a preferable synchronous clock; Produce the phy clock of GPON by said preferable synchronous clock; Recover said phy clock by optical network unit through GPON, and be benchmark, produce and said preferable synchronous clock clock synchronized with said phy clock.Compared with prior art, the present invention can realize that clock the whole network in GPON is synchronous with 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, said 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 said 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 said receiving element 703 receives and the said 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, said optical network unit comprises:
Phy clock acquiring unit 801 is used for obtaining through GPON the phy clock of the GPON that said 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 through GPON, and is benchmark with said phy clock, produces and said preferable synchronous clock clock synchronized.Compared with prior art, the present invention can realize that clock the whole network in GPON is synchronous with 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, said optical network unit also comprises:
Second timing signal generation unit 803, the phy clock of the GPON that is used for getting access to said phy clock acquiring unit 801 is a benchmark, produces second timing signal;
As shown in Figure 8, said 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, said system comprises:
The transmission system of the synchronised clock that the embodiment of the invention provides; Optical line terminal is confirmed a preferable synchronous clock; Produce the phy clock of GPON by said preferable synchronous clock; Optical network unit recovers said phy clock through GPON, and is benchmark with said phy clock, produces and said preferable synchronous clock clock synchronized.Compared with prior art, the present invention can realize that clock the whole network in GPON is synchronous with 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, said optical line terminal 901, also being used for said preferable synchronous clock is that benchmark produces first timing signal;
Said optical network unit 902, also being used for said 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; Be merely the embodiment of the embodiment of the invention; But the protection range of the embodiment of the invention is not limited thereto; Any technical staff who is familiar with the present technique field is in the technical scope that the present invention discloses, and 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 (12)
1. the transmission method of a synchronised clock is characterized in that, comprising:
Optical line terminal receives business data flow;
Optical line terminal is confirmed a preferable synchronous clock;
Optical line terminal is the phy clock that benchmark produces gigabit passive optical network (GPON) with said preferable synchronous clock;
Optical line terminal is that benchmark produces first timing signal with said preferable synchronous clock, calculates the speed difference between said business data flow and said first timing signal, and said speed difference and business data flow are carried out being sent to optical network unit after the GEM encapsulation; Perhaps, optical line terminal carries out GEM encapsulation with the original input rate of business data flow and said business data flow and is sent to optical network unit;
Optical network unit obtains said phy clock through GPON;
Optical network unit is a benchmark with said phy clock, produces and said preferable synchronous clock clock synchronized.
2. the transmission method of synchronised clock according to claim 1 is characterized in that, said optical line terminal confirms 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; It is characterized in that; When optical line terminal is that benchmark produces first timing signal with said preferable synchronous clock, calculate the speed difference between said business data flow and said first timing signal, when said speed difference and business data flow are carried out being sent to optical network unit after the GEM encapsulation; After said optical network unit obtains the step of said phy clock through GPON, also comprise:
Optical network unit is a benchmark with said phy clock, produces second timing signal;
Optical network unit carries out decapsulation to said speed difference and business data flow through the GEM encapsulation;
Optical network unit calculates the original input rate of said business data flow at the optical line terminal place according to said speed difference and second timing signal;
Optical network unit is according to said original input rate and second timing signal, and the synchronous output phy clock of input phy clock of generation and said business data flow is exported said business data flow.
4. the transmission method of synchronised clock according to claim 1; It is characterized in that; When optical line terminal carries out the original input rate of business data flow and said business data flow GEM encapsulation and is sent to optical network unit; After said optical network unit obtains the step of said phy clock through GPON, also comprise:
Optical network unit is a benchmark with said phy clock, produces second timing signal;
Optical network unit carries out decapsulation to said through the business data flow of GEM encapsulation and the original input rate of said business data flow;
Optical network unit is according to said original input rate and second timing signal, and the synchronous output phy clock of input phy clock of generation and said business data flow is exported said business data flow.
5. according to the transmission method of claim 3 or 4 described synchronised clocks, it is characterized in that, also comprise:
From with the output phy clock of said preferable synchronous clock clock synchronized and business data flow select one the tunnel, by the synchronised clock mouth output of optical network unit.
6. 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 said optical network unit obtains the step of said phy clock through GPON, also comprise:
The data flow of input BITS;
Optical line terminal carries out the GEM encapsulation with the data flow of said BITS, sends to optical network unit through GPON, comprises the quality information of preferable synchronous clock in the data flow of said BITS.
7. the transmission method of synchronised clock according to claim 6 is characterized in that, after said optical network unit obtains the step of said phy clock through GPON, also comprises:
Optical network unit carries out decapsulation to the data flow of said BITS;
Optical network unit is exported the data flow of said BITS.
8. the transmission method of synchronised clock according to claim 7 is characterized in that, also comprises:
Will with the BITS synchronised clock clock synchronized of said 2Mbit/s, by the output of the synchronised clock mouth of optical network unit.
9. an optical line terminal is characterized in that, comprising:
Receiving element is used to receive business data flow;
Clock is confirmed the unit, is used for confirming a preferable synchronous clock;
The phy clock generation unit, being used for said preferable synchronous clock is the phy clock that benchmark produces GPON;
The first timing signal for generating unit, being used for said 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 said receiving element receives and the generation of the said first timing signal for generating unit;
Encapsulation unit is used for said business data flow, speed difference or speed are carried out being sent to optical network unit after the GEM encapsulation.
10. an optical network unit is characterized in that, comprising:
The phy clock acquiring unit is used for obtaining through GPON the phy clock of the GPON that said optical line terminal produces;
The second timing signal generation unit, the phy clock of the GPON that is used for getting access to said phy clock acquiring unit is a benchmark, produces second timing signal;
Decapsulation unit is used for said 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 said 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 said original input rate and said second timing signal, and the synchronous output phy clock of input phy clock of generation and said business data flow is exported said business data flow;
Clock generating unit, the phy clock of the GPON that is used for getting access to said phy clock acquiring unit is a benchmark, produces and said preferable synchronous clock clock synchronized.
11. optical network unit according to claim 10 is characterized in that, also comprises:
The clock output unit is used for selecting one the tunnel from the output phy clock of said preferable synchronous clock clock synchronized and business data flow, by the synchronised clock mouth output of optical network unit.
12. the transmission system of a synchronised clock is characterized in that, comprising:
Optical line terminal is used for confirming a preferable synchronous clock, is the phy clock that benchmark produces GPON with this preferable synchronous clock; Be used for that also the original input rate of business data flow and said business data flow is carried out the GEM encapsulation and be sent to optical network unit; Perhaps, also being used for said preferable synchronous clock is that benchmark produces first timing signal, calculates the speed difference between said business data flow and said first timing signal, and said speed difference and business data flow are carried out being sent to optical network unit after the GEM encapsulation;
Optical network unit; Being used for obtaining the said phy clock that optical line terminal produces through GPON, is benchmark with said phy clock, produces second timing signal; Said business data flow, speed difference or speed through the GEM encapsulation is carried out decapsulation; According to said speed difference and second timing signal, the original input rate of computing service data flow is according to said original input rate and said second timing signal; The synchronous output phy clock of input phy clock of generation and said business data flow is exported said business data flow.
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2008101327867A CN101631014B (en) | 2008-07-14 | 2008-07-14 | Method, device and system for transmitting synchronous clock |
| PCT/CN2009/071382 WO2010006522A1 (en) | 2008-07-14 | 2009-04-21 | Method, device and system for transferring synchronous clocks |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2008101327867A CN101631014B (en) | 2008-07-14 | 2008-07-14 | Method, device and system for transmitting synchronous clock |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN200810185854A Division CN101630988A (en) | 2008-07-14 | 2008-07-14 | Method, device and system for transferring synchronous clock |
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| CN101631014A CN101631014A (en) | 2010-01-20 |
| CN101631014B true CN101631014B (en) | 2012-04-04 |
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| WO (1) | WO2010006522A1 (en) |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1933367A (en) * | 2006-10-09 | 2007-03-21 | 广州市高科通信技术股份有限公司 | TDM business realizing method based on Ethernet passive light network |
| CN101102158A (en) * | 2006-08-16 | 2008-01-09 | 华为技术有限公司 | Method and device for transmitting synchronization digital system service in passive optical network |
| CN201039198Y (en) * | 2006-09-18 | 2008-03-19 | 中兴通讯股份有限公司 | Network timing distribution system for Ethernet passive optical network |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6470032B2 (en) * | 2001-03-20 | 2002-10-22 | Alloptic, Inc. | System and method for synchronizing telecom-related clocks in ethernet-based passive optical access network |
| JP4680073B2 (en) * | 2006-01-27 | 2011-05-11 | 三菱電機株式会社 | PON system |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101102158A (en) * | 2006-08-16 | 2008-01-09 | 华为技术有限公司 | Method and device for transmitting synchronization digital system service in passive optical network |
| CN201039198Y (en) * | 2006-09-18 | 2008-03-19 | 中兴通讯股份有限公司 | Network timing distribution system for Ethernet passive optical network |
| CN1933367A (en) * | 2006-10-09 | 2007-03-21 | 广州市高科通信技术股份有限公司 | TDM business realizing method based on Ethernet passive light network |
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| Title |
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| JP特開2007-201842A 2007.08.09 |
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| WO2010006522A1 (en) | 2010-01-21 |
| CN101631014A (en) | 2010-01-20 |
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