CN102237940B - Method, system and device for transferring sync-status message (SSM) in passive optical network - Google Patents
Method, system and device for transferring sync-status message (SSM) in passive optical network Download PDFInfo
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Abstract
The embodiment of the invention discloses a method for transferring a sync-status message (SSM), which comprises the following steps: packaging an SSM of an OLT (optical line terminal) output clock into a corresponding SSM message according to a previously established SSM transfer channel by using a packaging format matched with the SSM transfer channel; and transferring the packaged SSM message to an optical network unit through the previously established SSM transfer channel. Correspondingly, the embodiment of the invention also provides a passive optical network system and an optical line terminal.
Description
Technical field
The present invention relates to communication technical field, more particularly, relate to a kind of method, system and equipment that transmits Synchronization Status Message in EPON.
Background technology
At access field, the transmission of EPON (PON, Passive Optical Network) be take optical fiber as transmission medium, has realized point-to-multipoint high bandwidth access, becomes the main flow direction of wideband data access development.Due to the popularization of wireless base station because of the contour broadband services of 3G, the bandwidth of up-downgoing carrying is more and more higher, and traditional SDH (Synchronous Digital Hierarchy) (SDH, Synchronous Digital Hierarchy) cannot satisfy the demands, therefore, the high bandwidth of PON has been brought new solution for moving carrying.
In mobile communication system, BTS service operation needs base station equipment to have high-quality system clock (frequency deviation is better than positive and negative 0.05PPM), optical line terminal equipment (the OLT of PON system, Optical LineTerminal) follow the tracks of behind upstream clock source, can by optical line terminal equipment OLT to the transmission channel clock between network unit/optical network terminal (ONU/ONT, Optical Network Unit/Optical Network Terminal) the clock signal of OLT to ONU/ONT.ONU/ONT gets after the clock signal of OLT, carries out phase-locked output, for upstream device (such as base station equipment) provides phy clock signal.But in existing communication system, upstream device cannot be known the clock quality of the phy clock signal that ONU/ONT provides, therefore cannot select quality preferably clock signal carry out phase locked track.
Summary of the invention
In view of this, the embodiment of the present invention provides a kind of method, system and equipment that transmits Synchronization Status Message in EPON.
The embodiment of the present invention provides a kind of method of transmitting Synchronization Status Message SSM in EPON, the method comprises: according to the SSM transmission channels of setting up in advance, adopt the encapsulation format matching with described SSM transmission channels, the SSM of OLT output clock is packaged into corresponding SSM message; By the SSM transmission channels of setting up in advance, the SSM message after encapsulation is sent to optical network unit
The embodiment of the present invention also provides a kind of passive network system, this system comprises: comprise optical line terminal OLT and at least one optical network unit ONU, described OLT is connected to described ONU by Optical Distribution Network, wherein, described OLT, the Synchronization Status Message SSM transmission channels of setting up in advance for basis, adopt the encapsulation format matching with described SSM transmission channels, the SSM of its output clock is packaged into corresponding SSM message, by the described SSM transmission channels of setting up in advance, the SSM message after encapsulation is sent to described ONU; Described ONU, for following the tracks of the output clock of described OLT, and receive described SSM message and from wherein extracting the SSM of described OLT output clock from described SSM transmission channels, according to extracted SSM, adjust the SSM of described ONU output clock, and the SSM of described ONU output clock is offered to upstream device.
The embodiment of the present invention also provides a kind of optical line terminal, and this optical line terminal comprises: receiver module, the reference clock and SSM corresponding to described reference clock that for receiving a plurality of signal source of clock, provide; Phase-locked module, for according to the reference clock that receives and corresponding SSM thereof, in conjunction with local clock signal source, carries out phase locked track to local clock signal, and using phase-locked rear clock signal as output clock and offer output module; SSM information module, for generating the SSM corresponding with described output clock, and the encapsulation format that adopts the SSM transmission channels with foundation in advance to match, the SSM of described output clock is packaged into corresponding SSM message and offers output module; Output module, for being sent to optical network unit by the SSM message after encapsulation by described SSM transmission channels.
The technical scheme that adopts the embodiment of the present invention to provide, ONU can be by being based upon the SSM transmission channels between OLT and ONU in advance, obtain the SSM of OLT output clock, thus, ONU can provide for the clockwork in downstream clock signal and and correct SSM, so that described downstream clockwork can obtain the clock quality of the clock signal of ONU output, and select quality preferably clock signal carry out phase locked track.
Accompanying drawing explanation
In order to be illustrated more clearly in the embodiment of the present invention or technical scheme of the prior art, to the accompanying drawing of required use in embodiment or description of the Prior Art be briefly described below, apparently, accompanying drawing in the following describes is only some embodiments of the present invention, for those of ordinary skills, do not paying under the prerequisite of creative work, can also obtain according to these accompanying drawings other accompanying drawing.
A kind of Synchronization Status Message transmission method flow chart that Fig. 1 provides for the embodiment of the present invention;
The structural representation of a kind of passive optical network that Fig. 2 provides for the embodiment of the present invention;
The structural representation of a kind of optical line terminal that Fig. 3 provides for the embodiment of the present invention;
A kind of GPON system clock synchronization principles structure chart that Fig. 4 provides for the embodiment of the present invention;
The flow chart of a kind of specific embodiment of Synchronization Status Message transmission method that Fig. 5 provides for the embodiment of the present invention;
The flow chart of the another kind of specific embodiment of Synchronization Status Message transmission method that Fig. 6 provides for the embodiment of the present invention;
The PLOAM message structure figure that Fig. 7 provides for the embodiment of the present invention;
The flow chart of another specific embodiment of Synchronization Status Message transmission method that Fig. 8 provides for the embodiment of the present invention;
The OMCI message structure figure that Fig. 9 provides for the embodiment of the present invention.
Embodiment
Below in conjunction with the accompanying drawing in the embodiment of the present invention, the technical scheme in the embodiment of the present invention is clearly and completely described, obviously, described embodiment is only the present invention's part embodiment, rather than whole embodiment.Embodiment based in the present invention, those of ordinary skills, not making the every other embodiment obtaining under creative work prerequisite, belong to the scope of protection of the invention.
The embodiment of the present invention provides a kind of Synchronization Status Message (Synchronization Status Message, SSM) transmission method, can solve ONU/ONT equipment in prior art and cannot export correct SSM to the clockwork in its downstream, and cause downstream clockwork cannot select preferably clock signal horizontal lock tracking of quality.For ease of describing, below ONU/ONT is referred to as to ONU.
The SSM information transmitting methods that the embodiment of the present invention provides can be applied in Optical Access Network, as EPON (PON) system.Described PON system can comprise OLT equipment, Optical Distribution Network and a plurality of ONU equipment, and wherein said OLT can be connected to described a plurality of ONU with point-to-multipoint form by described Optical Distribution Network.
The SSM information transmitting methods providing according to the embodiment of the present invention, before carrying out SSM transmission, first OLT needs correctly to generate the SSM of OLT clock, then set up and ONU between SSM transmission channel, a SSM who generates is being carried out to special message encapsulation, then passing through the message that set up SSM transmission channel carries SSM by this and pass to ONU, ONU is according to the special package form of OLT, SSM is extracted from message, thereby get the SSM of OLT clock signal.ONU can carry out phase locked track to the clock signal of OLT, and export its from this Receive message to SSM to the clockwork in downstream.
In specific embodiment, as shown in Figure 1, described SSM information transmitting methods can comprise the following steps:
Step 101:OLT follows the tracks of clock signal input, generates the SSM of OLT equipment self clock;
In step 101, OLT can receive a plurality of signal source of clock, and selects optimum clock source to follow the tracks of.When optimum external clock signal source is better than the local crystal oscillator of OLT, as as described in the clock grade of external clock signal source higher than local crystal oscillator, OLT can follow the tracks of the external clock signal source of described optimum, and obtain the SSM of this signal source of clock, and enter according to this optimum signal source of clock and carry out after phase locked track state in system, generate the SSM of OLT equipment self clock, i.e. the SSM of OLT clock signal.Wherein, the SSM of described OLT clock signal equals the SSM of the external clock signal source of described optimum.
If the clock quality of the external clock signal source of described optimum is lower than local crystal oscillator, OLT equipment switches to clock holdover mode or free-run mode, and the SSM value that now OLT equipment can self clock is set to equal the clock grade (as QL SEC) of the local crystal oscillator of OLT equipment.
Step 102: the SSM transmission channels according to setting up in advance, is packaged into the SSM message corresponding with described SSM transmission channels by described SSM;
In specific embodiment, OLT can set in advance SSM transmission channels with between ONU, for transmitting SSM information, or more specifically, transmits the SSM message that carries SSM information.Wherein, described SSM transmission channels can be GEM PORT passage, GEM PLOAM passage or GEM OMCI passage.
In step 102, when the SSM transmission channels of setting up between OLT and ONU is GEM PORT passage, for SSM can be transmitted in this passage, OLT can be packaged into SSM the ESMC message of standard, and the source MAC of this ESMC message will be set to the MAC Address of OLT equipment.Or OLT also can be packaged into SSM common Ethernet message, in message, 4 bit information of SSM are placed in low 4 of first byte of IP payload of Ethernet message and are gone, high 4 is all 0.Because Ethernet message requires minimum 64 bytes, other bytes of IP payload will be filled into message the length that Ethernet requires with 0.
When adopting GEM PLOAM passage to carry out the transmission of SSM between OLT and ONU, OLT can be packaged into SSM the message of the PLOAM type of message of appointment.
Or when adopting GEM OMCI passage to carry out the transmission of SSM between OLT and ONU, OLT can be packaged into SSM the message of the OMCI type of message of appointment.In this step, the packing forms of SSM need to decide according to the SSM transmission channels of setting up in advance between OLT and ONU.Above-mentioned various SSM transmission channels the concrete message format of SSM message (as EMSC message, PLOAM message, OMCI message etc.) of corresponding carrying SSM, below with reference to being described in detail respectively in each specific embodiment.
And, should be appreciated that SSM also can transmit by other passages except above-mentioned mentioned several SSM transmission channels and corresponding packing forms, and correspondingly according to this passage, encapsulate, the embodiment of the present invention is not done particular restriction.
Step 103: the SSM message after encapsulation is sent to described ONU by described SSM transmission channels.
After OLT is packaged into corresponding SSM message by the SSM of himself clock signal according to the form of the transmission channels of setting up in advance, this SSM message can be positioned in corresponding SSM transmission channels and be sent to object ONU.In addition, because PON system is point-to-multipoint network system, OLT generally can corresponding a plurality of ONU, between OLT and each ONU, can set up respectively corresponding SSM transmission channels, and OLT is when ONU to appointment sends SSM message, need by this SSM message be positioned over the corresponding transmission channels of target ONU on send.
Further, the SSM transmission method that the present embodiment provides can also comprise:
ONU has obtained after SSM message in SSM transmission channel, by the encapsulation specification of OLT, carries out corresponding decapsulation, thereby obtains the SSM of OLT clock signal.And, ONU can follow the tracks of OLT and transmit the clock signal of getting off, and adjust the SSM of its output clock, so that the SSM of the clock signal of its output (being the SSM of ONU clock signal) equals the SSM that it gets from the SSM message by the transmission of described SSM transmission channels.
Further, the SSM of the ONU clock signal after the exportable phase locked track of ONU and this ONU clock signal is to the clockwork in downstream.
The Synchronization Status Message transmission method that adopts the embodiment of the present invention to provide, ONU can be by being based upon the SSM transmission channels between OLT and ONU in advance, obtain the SSM of OLT clock signal, make thus ONU can provide for the clockwork (as mobile load bearing equipment and other system) in downstream clock signal and and correct SSM, so that described downstream clockwork can obtain the clock quality of the clock signal of ONU output, and select quality preferably clock signal carry out phase locked track.
Accordingly, the embodiment of the present invention also provides a kind of passive optical network PON system and a kind of optical line terminal OLT that can be applied in described PON system.Described PON system can be GPON system.Refer to Fig. 2, described PON system comprises optical line terminal OLT 201 and at least one optical network unit ONU 202, and described OLT 201 is connected to described at least one ONU 202 by Optical Distribution Network 203 in point-to-multipoint mode.
Wherein, the Synchronization Status Message SSM transmission channels that described OLT 201 can set up in advance for basis, adopt the encapsulation format matching with described SSM transmission channels, the SSM of its output clock is packaged into corresponding SSM message, by the described SSM transmission channels of setting up in advance, the SSM message after encapsulation is sent to described ONU 202;
Described ONU 202 can be for following the tracks of the output clock of described OLT 201, and receive described SSM message and from wherein extracting the SSM of described OLT output clock from described SSM transmission channels, according to extracted SSM, adjust the SSM of described ONU output clock, and the SSM of described ONU output clock is offered to upstream device.
In specific embodiment, the described SSM transmission channels of setting up in advance comprises one of GEM PORT passage, GEM PLOAM passage, GEM OMCI passage.
And when the described SSM transmission channels of setting up is in advance GEM PORT passage, described SSM message is the ESMC message that carries the SSM of OLT output clock; Or,
When the described SSM transmission channels of setting up is in advance GEM PLOAM passage, described SSM message for carrying the descending GEM frame of the SSM of OLT output clock in PLOAM field; Or,
When the described SSM transmission channels of setting up is in advance GEM OMCI passage, described SSM message is the OMCI message that carries the SSM of OLT output clock.
Based on above method and system, the optical line terminal OLT that the embodiment of the present invention provides can be as shown in Figure 3.The OLT that the embodiment of the present invention provides can comprise: receiver module 301, phase-locked module 302, SSM information module 303 and output module 304.
Wherein, described receiver module 301 provides for receiving a plurality of signal source of clock reference clock and SSM corresponding to described reference clock;
Described phase-locked module 302, for according to the reference clock that receives and corresponding SSM thereof, in conjunction with local clock signal source, carries out phase locked track to local clock signal, and using phase-locked rear clock signal as output clock and offer output module 304;
Described SSM information module 303, for generating the SSM corresponding with described output clock, and the encapsulation format that adopts the SSM transmission channels with foundation in advance to match, the SSM of described output clock is packaged into corresponding SSM message and offers output module 304;
Described output module 304, for being sent to optical network unit by the SSM message after encapsulation by described SSM transmission channels.
Specific embodiment one
In conjunction with said method, system, device and concrete application scenarios, technical scheme provided by the present invention is described further.
The various SSM transmission methods that the embodiment of the present invention provides can be applicable to GPON system, and as shown in Figure 4, it is the synchronous principle assumption diagram of GPON system clock.OLT can obtain a plurality of reference clock source signals by T1 interface, E1 interface and synchronous ethernet interface etc., and described synchronous ethernet interface, T1 interface and E1 interface can also send the corresponding SSM of each reference clock source signal to OLT.Such as synchronous ethernet interface can provide synchronised clock source signal, and by ESMC message, transmit the SSM information of this clock source signals.E1 and T1 interface can provide frame synchronizing signal and code stream synchronizing signal as clock source signals, and by Sa bit information, transmit the SSM information of this clock source signals.
OLT is after receiving the SSM of reference clock source signal and correspondence thereof, the phase-locked module of its inner OLT can select to obtain optimum reference clock source signal and corresponding SSM thereof, and according to obtained reference clock source signal and the SSM of this clock source, in conjunction with local crystal oscillator, carry out phase-lockedly, and the OLT clock signal after further phase-locked by the output of its inner clock signal distribution module is to GPON interface.In addition, OLT also can generate the SSM information of current OLT clock signal by its inner SSM information module, offer equally GPON interface.It should be noted that, OLT can, according to the phase locked state of phase-locked module, generate the SSM of corresponding OLT clock.
Particularly, if the phase-locked module of OLT in tracking mode, the SSM of the OLT clock that SSM information module generates equals the SSM of current tracking signal source of clock; If the phase-locked module of OLT is in freedom or hold mode, the SSM of the OLT clock signal that SSM information module generates equals the clock instruction level of local crystal oscillator.
Afterwards, between OLT and ONU, can by the 8K frame synchronizing signal of GPON physical layer, carry out the transmission of clock signal, its output clock is delivered to ONU.In addition, between OLT and each ONU, also set up and have special-purpose SSM to pass through in advance, and when transmitting OLT clock signal, OLT can, by described SSM transmission channels, offer corresponding ONU by the SSM of its output clock.
Finally, ONU receives OLT clock signal and corresponding SSM thereof by described SSM transmission channels, and follow the tracks of OLT equipment clock, make the SSM of clock signal of himself output equal the SSM of described OLT clock signal, and by ONU clock signal and corresponding SSM thereof, by corresponding interface, export to upstream device respectively, such as base station etc.Like this, upstream device just can select optimum clock source to carry out phase locked track according to received SSM, and when the quality of clock source is during all lower than local crystal oscillator, the clock phase-locked loop state of upstream device just can be switched to and keep or free state.
Particularly, the SSM transmission method that the first specific embodiment of the present invention provides can be as shown in Figure 5, and it comprises:
Between step 501:OLT and ONU, set up in advance special-purpose GEM PORT passage as for transmitting the SSM transmission channels of SSM;
In step 501, for carry out the transmission of SSM between OLT and ONU, need between OLT and ONU, set up in advance special-purpose SSM transmission channels, in the present embodiment, the transmission of carrying out SSM of special-purpose GEM PORT passage is set up in employing, and this special-purpose GEM PORT passage can not be used further to the transmission of other business datums, wherein, further, the GEMPORT passage that the present embodiment is set up can be the passage of GEM PORT ID=4094, can adopt the passage of other ID, the present embodiment is not done particular restriction to this yet.
It should be noted that, because an OLT generally can corresponding a plurality of ONU, therefore, when setting up SSM transmission channels, need corresponding each ONU set up respectively special-purpose SSM transmission channels.
Step 502:OLT obtains SSM, and SSM is packaged into ESMC (EthernetSynchronization Messaging Channel) message;
In step 502, because OLT will carry out the transmission of SSM by the GEM PORT passage of setting up in advance, therefore, OLT, after obtaining SSM, need to encapsulate obtained SSM, to realize SSM, can in the GEM PORT passage of being set up, transmit.
In the present embodiment, SSM can be encapsulated according to the form of ESMC message, and ESMC message structure form can reference table 1.Wherein, SSM leaves the beginning of the Data and Padding field of described EMSC message in TLV form, and the LTV form of SSM is in Table 2.
The form of table 1 ESMC message
| Byte | Size | Implication |
| 1-6 | 6 octets | Destination Address＝01-80-C2-00-00-02(hex) |
| 7-12 | 6 octets | Source Address |
| 13-14 | 2 octets | Slow Protocol Ethertype＝88-09(hex) |
| 15 | 1 octets | Slow Protocol Subtype＝0A(hex) |
| 16-18 | 3 octets | ITU-OUI＝00-19-A7(hex) |
| 19-20 | 2 octets | ITU Subtype |
| 21 | 4 bits | Version |
| 1 bit | Event flag | |
| 3 bits | Reserved | |
| 22-24 | 3 octets | Reserved |
| 25-1532 | 36-1490 octets | Data and Padding |
| Last 4 | 4 octets | FCS |
The TLV of table 2 SSM (Type Length Value) form
| 8 bits | Type：0x01 |
| 16 bits | Length：0x04 |
| 4 bits | 0(unused) |
| 4 bits | SSM code |
Particularly, described SSM can comprise 4 bit, and the SSM of described 4 bit fixedly leaves in the low 4bit of the 28th byte of ESMC message.And, in packaged ESMC message, source MAC that can be using the MAC Address of OLT as this message, by this MAC Address, ONU can know that whether received SSM is from OLT.
Further, the SSM message encapsulation that the present embodiment is used, can be EMSC, also can be other the Ethernet message that can transmit by GEM PORT passage, as long as SSM is correctly encapsulated in message, the consensus processing of OLT and ONU, the present embodiment is not done particular restriction to this.
The ESMC message that carries SSM, the GEM PORT by appointment passes to ONU to step 503:OLT.
In step 503, due between OLT and different ONU, there is corresponding GEM PORT passage, therefore, OLT is when carrying the ESMC message of SSM described in transmitting to certain ONU, this message can be positioned over to the corresponding GEM PORT with this ONU, the GEM PORT passage corresponding by this GEM PORT is sent to object ONU.
After completing above-mentioned steps, ONU obtains ESMC message on the GEM of appointment PORT, and parses the SSM of its carrying, as the SSM of OLT clock signal.And, when ONU can follow the tracks of OLT clock signal, and allow the SSM of output clock of ONU equal the SSM of OLT clock signal, and the SSM that further exports this ONU clock signal is to upstream device.In other embodiments of the invention, ONU, after receiving the SSM of OLT tranmitting data register signal and correspondence thereof, all can adopt said method to carry out subsequent operation.
Wherein, the SSM that ONU parses obtains OLT clock quality information, and particular content can it should be noted that referring to table 3 and table 4, in other embodiments of the invention, all can employing table 3 and table 4 shown in content carry out the definition of clock instruction level.
Table 3 is the SSM of Option1 definition G.781
| SSM coding | Clock grade | Implication |
| 0010 | QL-PRC | Follow the tracks of PRC, G.811 |
| 0100 | QL-SSU-A | Follow the tracks of SSU, Type I or TypeV G.812 |
| 1000 | QL-SSU-B | Follow the tracks of SSU, VI G.812 |
| 1011 | QL-SEC | Follow the tracks of SEC, Option I G.813 |
| 1111 | QL-DNU | Not traceable clock source |
Table 4 is the SSM of Option2 definition G.781
| SSM coding | Clock grade | Implication |
| 0001 | QL-PRS | Follow the tracks of PRC, G.811 |
| 0000 | QL-STU | Unknowable clock source, does not carry QL information |
| 0111 | QL-ST2 | Follow the tracks of 2 grades of clocks, G.812 Type II |
| 0100 | QL-TNC | Follow the tracks of transit exchange's Dot Clock, G.812 Type V |
| 1101 | QL-ST3E | Follow the tracks of 3 grades and strengthen clock, G.812 Type III |
| 1010 | QL-ST3 | Follow the tracks of 3 grades of clocks, G.812 Type IV |
| 1100 | QL-SMC | Follow the tracks of SONET clock, G.813 Option II |
| 1110 | QL-PROV | The interim clock grade distributing of webmaster |
| 1111 | QL-DUS | Not traceable clock source |
Specific embodiment two
In the present embodiment, between OLT and ONU, can be used as SSM transmission channels by the descending GEM PLOAM of OLT (Physical Layer OAM) passage, so that the SSM of OLT clock signal is sent to ONU, concrete steps as shown in Figure 6:
Step 601:OLT obtains SSM, and the SSM that will transmit is encapsulated in to the PLOAM field in GEM frame.
PLOAM field is for transmitting physical layer OAM information between OLT and ONU, in uplink and downlink frame, there is definition, owing to needing the SSM by OLT clock signal to be sent to ONU from OLT in the present embodiment, so the present embodiment can carry the SSM of described OLT clock signal by the PLOAM field in descending GEM frame.OLT generates the PLOAM field in GEM frame according to obtained SSM, in the present embodiment, can expand existing GEM PLOAM message, so that the SSM of OLT clock signal is carried on wherein.Refer to Fig. 7, it is the structural representation of PLOAM field in the descending GEM frame of the present embodiment employing.Described PLOAM field comprises:
ONU ID is 1 byte, represents which ONU is this PLOAM message pass to.In specific embodiment, for once SSM message broadcasting to ONU all under PON port, the embodiment of the present invention can be expanded ONU ID, such as being expanded to as 0xFF, this PLOAM message of this value representation is not to send to specific ONU, but is broadcast to all ONU.Should be appreciated that, above-mentionedly about ONU ID being defined as to 0xFF, also meet GEM PLOAM standard.
In the PLOAM of descending GEM frame field, Message ID is 1 byte, and this information definition transmits the information type of PLOAM, can support at most 256 types.Defined descending PLOAM information type has 19 kinds at present, and up have 9 kinds.In the agreement that the present invention formulates, specify a current untapped Message ID as the type of message (as Message ID=100) of SSM.
Data is 10 bytes, the PLOAM message content that this message transmission is concrete.Because the SSM content of embodiment of the present invention definition is 4 bit, in the present embodiment, can adopt 4 bit of first byte low level of Data to deposit SSM content, high-order 4 bit are fixed as preset value, such as being fixed as 0, meanwhile, rear 9 bytes of Data field also can be fixed as 0, can expand use in the future.
Step 602:OLT is sent to ONU by GEM PLOAM passage by the GEM frame that carries the SSM of OLT clock signal.
Step 603:ONU receives described GEM frame from GEM PLOAM passage, and from PLOAM field wherein, obtains the SSM of OLT clock signal.
Further, ONU can carry out clock tracing according to the SSM of described OLT clock signal, and exports accordingly ONU clock signal and corresponding SSM thereof, the correlation step that specifically can consult above-described embodiment.
Specific embodiment three
In the present embodiment, between OLT and ONU, by the descending GEM OMCI of OLT (OpticalNetwork Termination Management and Control Interface) passage, be used as S SM transmission channels, so that the SSM of OLT clock signal is sent to ONU, concrete steps as shown in Figure 8.
Step 801:OLT obtains SSM, and the SSM that will transmit is encapsulated in to GEM OMCI message;
Particularly, OLT can realize the functions such as fault management, configuration management, performance management and safety management to ON by OMCI message.In the present embodiment, can, by carry SSM message in OMCI message, realize the transmission of SSM between OLT and OUT.
The present embodiment utilizes OMCI message to carry SSM for realizing, can to ITU-T G.984.4 the OMCI protocol massages of standard expand, the SSM of OLT clock signal is carried on wherein.Refer to Fig. 9, the frame structure schematic diagram of the OMCI message that it can adopt for the present embodiment.Described OMCI message can comprise:
ATM header/GEM header field, wherein, this field is controlled generation automatically by OLT, and generally length is 5 bytes;
Transaction correlation identifier field, this field for presentation of events type, considers that the OMCI message of transmitting SSM belongs to event type in OMCI message, therefore, in the present embodiment, it is 0 entirely that this field can be fixed;
Message type field, represents in this field that the field of the type of message has 5 bytes, therefore can represent 32 kinds of OMCI type of messages, and the type of message of 4-28 is wherein by standard definition.In order to realize, transmit SSM, the present invention selects a type of message (as Message type=30), the type of message transmitting as SSM from the 0-3 of current not use and 29-31;
Device identifier field, this field is controlled generation automatically by OLT, at this, does not limit;
Message Contents field, in the present embodiment, this field has 32 bytes for carrying the type of message content of appointment.Because the SSM content of standard is 4 bit (specifically can with reference to table 2 and table 3), in the agreement that the present invention formulates, specify 4 bit of first byte low level of Message Contents to deposit SSM content, high-order 4 bit are fixed as 0, simultaneously, rear 31 bytes of Message Contents are fixed as 0, can expand use in the future.
Step 802:OLT, by GEM OMCI passage, is passed to ONU by the OMCI message that carries the SSM of OLT clock signal.
Step 803:ONU receives described OMCI message from GEM OMCI passage, and from Message Contents field wherein, obtains the SSM of OLT clock signal, and carries out respective handling according to described SSM, specifically can consult above-described embodiment.
SSM transmission method based on providing about various embodiments of the invention above, it is a kind of for transmit the system of SSM at EPON that the embodiment of the present invention also further provides, it can comprise OLT, ONU and the Optical Distribution Network ODN transmitting for the signal of realizing between described OLT and ONU, and wherein said OLT is connected to described ONU by described Optical Distribution Network in point-to-multipoint mode.Described OLT and ONU can carry out the corresponding steps of above-mentioned SSM transmission method, and particularly, described OLT and ONU can arrange corresponding module (software module, hardware module or software and hardware combining module) by portion within it and realize.
One of ordinary skill in the art will appreciate that: all or part of step that realizes said method embodiment can complete by the relevant hardware of program command, aforesaid program can be stored in a computer read/write memory medium, this program, when carrying out, is carried out the step that comprises said method embodiment; And aforesaid storage medium comprises: various media that can be program code stored such as ROM (Read-Only Memory, read-only store-memory body), RAM (RandomAccess Memory, random store-memory body), magnetic disc or CDs.
Above-mentioned explanation to the disclosed embodiments, makes professional and technical personnel in the field can realize or use the present invention.To the multiple modification of these embodiment, will be apparent for those skilled in the art, General Principle as defined herein can, in the situation that not departing from the spirit or scope of the present invention, realize in other embodiments.Therefore, the present invention will can not be restricted to these embodiment shown in this article, but will meet the widest scope consistent with principle disclosed herein and features of novelty.
Claims (11)
1. in EPON, transmit a method of Synchronization Status Message SSM, it is characterized in that, comprising:
OLT receives a plurality of signal source of clock, and select optimum clock source to follow the tracks of, when optimum external clock signal source is better than the local crystal oscillator of OLT, OLT follows the tracks of the external clock signal source of described optimum, and obtain the SSM of this signal source of clock, and enter according to this optimum signal source of clock and carry out after phase locked track state in system, the SSM of OLT equipment self clock generated, wherein, the SSM of described OLT clock signal equals the SSM of the external clock signal source of described optimum;
According to the SSM transmission channels of setting up in advance, adopt the encapsulation format matching with described SSM transmission channels, the SSM of OLT output clock is packaged into corresponding SSM message;
By the described SSM transmission channels of setting up in advance, the SSM message after encapsulation is sent to optical network unit, wherein, the corresponding optical network unit described at least one of a described OLT.
2. method according to claim 1, is characterized in that, the described SSM transmission channels of setting up in advance comprises GEM PORT passage, GEM PLOAM passage or GEM OMCI passage.
3. method according to claim 2, is characterized in that, when the described SSM transmission channels of setting up is in advance GEM PORT passage, the step that the described SSM by OLT output clock is packaged into corresponding SSM message comprises:
The SSM of OLT output clock is encapsulated as to ESMC message, and the content carrying of wherein said SSM is in the data stuffing Data of the ESMC message being packaged into and Padding field.
4. method according to claim 2, is characterized in that, when the described SSM transmission channels of setting up is in advance GEM PLOAM passage, the step that the described SSM by OLT output clock is packaged into corresponding SSM message comprises:
The SSM of OLT output clock is encapsulated as to descending GEM frame, and the content carrying of wherein said SSM is in the PLOAM field of the descending GEM frame being packaged into.
5. method according to claim 2, is characterized in that, when the described SSM transmission channels of setting up is in advance GEM OMCI passage, the step that the described SSM by OLT output clock is packaged into corresponding SSM message comprises:
The SSM of OLT output clock is encapsulated as to OMCI message, and the content carrying of wherein said SSM is in the message content Message of the OMCI message being packaged into Contents field.
6. a passive network system, is characterized in that, comprises optical line terminal OLT and at least one optical network unit ONU, and described OLT is connected to described ONU by Optical Distribution Network, wherein,
Described OLT, be used for receiving a plurality of signal source of clock, and select optimum clock source to follow the tracks of, when optimum external clock signal source is better than the local crystal oscillator of OLT, described OLT follows the tracks of the external clock signal source of described optimum, and obtain the SSM of this signal source of clock, and enter according to this optimum signal source of clock and carry out after phase locked track state in system, generate the SSM of described OLT equipment self clock, wherein, the SSM of described OLT clock signal equals the SSM of the external clock signal source of described optimum, and according to the Synchronization Status Message SSM transmission channels of setting up in advance, adopt the encapsulation format matching with described SSM transmission channels, the SSM of its output clock is packaged into corresponding SSM message, by the described SSM transmission channels of setting up in advance, SSM message after encapsulation is sent to described ONU, described ONU, for following the tracks of the output clock of described OLT, and receive described SSM message and from wherein extracting the SSM of described OLT output clock from described SSM transmission channels, according to extracted SSM, adjust the SSM of described ONU output clock, and the SSM of described ONU output clock is offered to upstream device.
7. system according to claim 6, is characterized in that, the described SSM transmission channels of setting up in advance comprises one of GEM PORT passage, GEM PLOAM passage, GEM OMCI passage.
8. system according to claim 7, is characterized in that,
When the described SSM transmission channels of setting up is in advance GEM PORT passage, described SSM message is the ESMC message that carries the SSM of OLT output clock; Or,
When the described SSM transmission channels of setting up is in advance GEM PLOAM passage, described SSM message for carrying the descending GEM frame of the SSM of OLT output clock in PLOAM field; Or,
When the described SSM transmission channels of setting up is in advance GEM OMCI passage, described SSM message is the OMCI message that carries the SSM of OLT output clock.
9. an optical line terminal OLT, is characterized in that, comprising:
Receiver module, the reference clock and SSM corresponding to described reference clock that for receiving a plurality of signal source of clock, provide;
Phase-locked module, the reference clock receiving for basis and corresponding SSM thereof, in conjunction with local clock signal source, local clock signal is carried out to phase locked track, and using phase-locked rear clock signal as output clock and offer output module, according to a plurality of reference clocks that receive, select optimum clock source to follow the tracks of, when optimum external clock signal source is better than the local crystal oscillator of OLT, OLT follows the tracks of the external clock signal source of described optimum;
SSM information module, for generating the SSM corresponding with described output clock, and the encapsulation format that adopts the SSM transmission channels with foundation in advance to match, the SSM of described output clock is packaged into corresponding SSM message and offers output module;
Output module, for the SSM message after encapsulation is sent to optical network unit by described SSM transmission channels, wherein, the corresponding optical network unit described at least one of described OLT.
10. OLT according to claim 9, is characterized in that, the described SSM transmission channels of setting up in advance comprises one of GEM PORT passage, GEM PLOAM passage, GEM OMCI passage.
11. OLT according to claim 10, is characterized in that,
When the described SSM transmission channels of setting up is in advance GEM PORT passage, described SSM message is the ESMC message that carries the SSM of OLT output clock; Or,
When the described SSM transmission channels of setting up is in advance GEM PLOAM passage, described SSM message for carrying the descending GEM frame of the SSM of OLT output clock in PLOAM field; Or,
When the described SSM transmission channels of setting up is in advance GEM OMCI passage, described SSM message is the OMCI message that carries the SSM of OLT output clock.
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| CN102664699A (en) * | 2012-04-12 | 2012-09-12 | 中兴通讯股份有限公司南京分公司 | Method and device for selecting clock sources of microwave network elements |
| CN102946291A (en) * | 2012-11-12 | 2013-02-27 | 华为技术有限公司 | Clock maintaining method and clock equipment |
| CN104579529B (en) * | 2013-10-22 | 2018-08-17 | 中国移动通信集团公司 | A kind of method and apparatus of Synchronization Status Message |
| CN104270433B (en) * | 2014-09-23 | 2017-11-07 | 烽火通信科技股份有限公司 | Distributed SSM protocol processing systems and method based on complicated packet switching system |
| CN105703893A (en) * | 2014-11-25 | 2016-06-22 | 中兴通讯股份有限公司 | Clock source attribute synchronization method, clock source attribute synchronization device and clock source attribute synchronization system |
| CN108429606A (en) * | 2017-02-13 | 2018-08-21 | 中兴通讯股份有限公司 | The method of passing time status information, OLT, ONU and system |
| CN115913369A (en) * | 2021-09-30 | 2023-04-04 | 上海诺基亚贝尔股份有限公司 | Communication method and apparatus in passive optical network and computer readable medium |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101047554A (en) * | 2006-05-17 | 2007-10-03 | 华为技术有限公司 | Management method and system for broadband access network far-end node |
| CN101547085A (en) * | 2009-04-29 | 2009-09-30 | 华为技术有限公司 | Physical layer port master-slave configuration method, device and communication system |
Family Cites Families (2)
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-
2010
- 2010-05-04 CN CN201010163222.7A patent/CN102237940B/en active Active
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101047554A (en) * | 2006-05-17 | 2007-10-03 | 华为技术有限公司 | Management method and system for broadband access network far-end node |
| CN101547085A (en) * | 2009-04-29 | 2009-09-30 | 华为技术有限公司 | Physical layer port master-slave configuration method, device and communication system |
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