WO2015184604A1 - Wavelength switching method, device and system - Google Patents

Wavelength switching method, device and system Download PDF

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Publication number
WO2015184604A1
WO2015184604A1 PCT/CN2014/079152 CN2014079152W WO2015184604A1 WO 2015184604 A1 WO2015184604 A1 WO 2015184604A1 CN 2014079152 W CN2014079152 W CN 2014079152W WO 2015184604 A1 WO2015184604 A1 WO 2015184604A1
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WO
WIPO (PCT)
Prior art keywords
wavelength
onu
olt
time
wavelength channel
Prior art date
Application number
PCT/CN2014/079152
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French (fr)
Chinese (zh)
Inventor
刘德坤
高建河
高波
Original Assignee
华为技术有限公司
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Publication date
Application filed by 华为技术有限公司 filed Critical 华为技术有限公司
Priority to PCT/CN2014/079152 priority Critical patent/WO2015184604A1/en
Publication of WO2015184604A1 publication Critical patent/WO2015184604A1/en

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Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04J—MULTIPLEX COMMUNICATION
    • H04J14/00—Optical multiplex systems
    • H04J14/02—Wavelength-division multiplex systems
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04Q—SELECTING
    • H04Q11/00—Selecting arrangements for multiplex systems

Definitions

  • Embodiments of the present invention relate to optical communication technologies, and in particular, to a wavelength switching method, apparatus, and system. Background technique
  • Passive Optical Network (PON) technology is currently a major broadband access technology.
  • TDM Time Division Multiplexing
  • WDM Wave Division Multiplexing
  • TDM Time Wave Division Multiplexing
  • the TWDM PON system is a point-to-multipoint communication system.
  • the optical line terminal (OLT) at the central office and the optical network unit (ONU) on the user side use multiple wavelength channels for data.
  • each ONU operates in one of the wavelength channels.
  • the OLT uses the downlink wavelength corresponding to each wavelength channel to broadcast downlink data to multiple ONUs working in the wavelength channel.
  • the ONU of each wavelength channel can adopt the time slot allocated by the OLT.
  • the upstream wavelength of the wavelength channel sends uplink data to the OLT.
  • the downlink wavelength and the uplink wavelength used by the ONU can be dynamically adjusted.
  • the OLT finds that the load of a certain wavelength channel is too large, it can send a wavelength switching instruction to the ONU working in the wavelength channel, instructing the ONU to switch to the lighter wavelength channel by adjusting its upstream wavelength and/or downstream wavelength.
  • the OLT needs to first send a wavelength switching command to the ONU, and the ONU starts to perform wavelength switching after receiving the wavelength tuning command, and the OLT waits for the ONU to complete the wavelength switching.
  • the ONU is continuously sent an inquiry command to complete the handover.
  • the ONU sends a message that the wavelength switching has been completed to the OLT.
  • the OLT receives the message. Then, the information such as the downlink data and the time slot authorization of the uplink data is sent to the ONU, so that the OLT and the ONU can resume normal service communication.
  • the OLT needs to continuously send an inquiry command to the ONU until the message sent by the ONU indicating that the wavelength switching has been completed is restarted to re-transmit the service data, resulting in a long service interruption time.
  • the embodiment of the invention provides a wavelength switching method, device and system, which are used to solve the technical problem that the service interruption time is too long due to the repeated information interaction between the OLT and the ONU in the wavelength switching operation in the prior art.
  • the first aspect provides a wavelength switching method, including:
  • the OLT sends a wavelength switching command to the ONU, where the wavelength switching command is used to instruct the ONU to switch from the source wavelength channel to the destination wavelength channel, where the wavelength switching command carries a start time t0, where the t0 is used to indicate the ONU Switching from the source wavelength channel to the target wavelength channel at time t0;
  • the OLT starts to send downlink data to the ONU through the destination wavelength channel, and the time T is that the ONU switches from the source wavelength channel to the The time required for the destination wavelength channel.
  • the method before the sending, by the OLT, the wavelength switching command to the ONU, the method further includes:
  • the OLT acquires the time T reported by the ONU.
  • the wavelength switching command carries an identifier of the destination wavelength channel; or carries an uplink wavelength of the destination wavelength channel And / or downstream wavelength.
  • the wavelength switching command carries wavelength switching type information, where the wavelength switching type information is used to indicate that the uplink wavelength is switched. / or downstream wavelength.
  • the method further includes:
  • the OLT stores the downlink data in a local storage; After the OLT stores the downlink data in the local storage, the method further includes: when the OLT receives the uplink data or the wavelength switch completion message sent by the ONU in the destination wavelength channel, the OLT releases the local Downstream data stored in the memory.
  • the method further includes:
  • the OLT If the OLT does not receive the uplink data or the wavelength switching completion message sent by the ONU after the preset wavelength switching timing, the OLT falls back to the source wavelength channel in the ONU. After the source wavelength channel sends the downlink data stored in the local memory to the ONU, or after the ONU re-registers, the OLT re-registers on the wavelength channel re-registered by the ONU. The ONU transmits the downlink data stored in the local storage.
  • the method further includes:
  • the OLT starts to send an uplink time slot grant to the ONU through the destination wavelength channel from the time T0 at the time t0.
  • the second aspect provides a wavelength switching method, including:
  • the ONU sends a wavelength switching time message to the OLT, where the wavelength switching time message carries a time T, where the time T is the time required for the ONU to switch from the source wavelength channel to the destination wavelength channel, and the T is used to indicate the OLT. Waiting time, the waiting time is the waiting time between the wavelength switching from the ONU and the downlink data sent by the OLT.
  • the ONU receives the wavelength switching command sent by the OLT, where the wavelength switching command is used to instruct the ONU to switch from a source wavelength channel to a destination wavelength channel, where the wavelength switching command carries a starting time t0, T0 is used to indicate that the ONU starts to switch from the source wavelength channel to the destination wavelength channel at time t0;
  • the ONU starts to switch from the source wavelength channel to the destination wavelength channel at the time t0;
  • the ONU After switching to the destination wavelength channel, the ONU receives downlink data sent by the OLT through the destination wavelength channel.
  • the wavelength switching command carries Describe the identifier of the destination wavelength channel; or carry the upstream wavelength and/or the downstream wavelength of the destination wavelength channel.
  • the wavelength switching command further carries wavelength switching type information, where the wavelength switching type information includes switching an uplink wavelength and / or indication of the downstream wavelength.
  • the ONU is switched from the source wavelength channel at the time t0 After the destination wavelength channel, the method further includes:
  • the ONU receives the uplink time slot grant sent by the OLT through the destination wavelength channel from the time t0 and the time T.
  • a third aspect provides an apparatus for wavelength switching, comprising:
  • a processing unit configured to generate a wavelength switching command, and instruct to send the wavelength switching command to the ONU, where the wavelength switching command is used to instruct the ONU to switch from the source wavelength channel to the destination wavelength channel, where the wavelength switching command carries Starting at time t0, the t0 is used to indicate that the ONU starts to switch from the source wavelength channel to the destination wavelength channel at time t0; and is further configured to indicate that the time elapses from the time t0, start to pass The destination wavelength channel sends downlink data to the ONU.
  • the apparatus for wavelength switching further includes: a sending unit, configured to send a wavelength switching command to the ONU according to an indication of the processing unit; The time T is sent to the ONU through the destination wavelength channel, where the time T is the time required for the ONU to switch from the source wavelength channel to the destination wavelength channel.
  • the device for wavelength switching further includes a receiving unit, configured to acquire the time T reported by the ONU.
  • the wavelength switching command carries an identifier of the destination wavelength channel
  • the wavelength switching command further carries wavelength switching type information, where the wavelength switching type information is used to indicate that the uplink wavelength is switched. And / or downstream wavelength.
  • the apparatus for wavelength switching further includes: a storage unit, configured to: The downlink data is stored in a local memory.
  • the apparatus for wavelength switching further includes:
  • the processing unit is configured to release the downlink data stored in the local storage when the OLT receives the uplink data or the wavelength switch completion message sent by the ONU in the destination wavelength channel.
  • the sending unit is further configured to: when the OLT is not in the destination wavelength channel after a preset wavelength switching timing time Receiving the uplink data or the wavelength switch completion message sent by the ONU, after the ONU falls back to the source wavelength channel, sending the downlink stored in the local memory to the ONU in the source wavelength channel. Data, or after the ONU re-registers, retransmits the downlink data stored in the local memory to the ONU on the wavelength channel re-registered by the ONU.
  • the sending unit is further configured to: The time T sends an uplink time slot grant to the ONU through the destination wavelength channel.
  • a fourth aspect provides an apparatus for wavelength switching, including:
  • a sending unit configured to send a wavelength switching time message to the OLT, where the wavelength switching time message carries a time T, where the time T is a time required for the ONU to switch from the source wavelength channel to the destination wavelength channel, where the T is used to indicate the The waiting time of the OLT, the waiting time is the waiting time between the wavelength switching from the ONU and the downlink data sent by the OLT.
  • a receiving unit configured to receive a wavelength switching command sent by the optical line terminal OLT, where the wavelength switching command is used to instruct the ONU to switch from a source wavelength channel to a destination wavelength channel, where the wavelength switching command carries a starting time t0, Instructing the ONU to start switching from the source wavelength channel to the destination wavelength channel at time t0;
  • a processing unit configured to switch from the source wavelength channel to the destination wavelength channel at the time of to;
  • the receiving unit is further configured to: after switching to the destination wavelength channel, receive downlink data sent by the OLT through the destination wavelength channel.
  • the wavelength switching command carries an identifier of the destination wavelength channel;
  • the wavelength switching command further carries wavelength switching type information, where the wavelength switching type information includes indication information for switching an uplink wavelength and/or a downlink wavelength.
  • the fifth aspect provides a passive optical network system, including an OLT and an ONU, where the OLT connects at least one of the ONUs by using an ODN, where the OLT includes any possible implementation manner of the third aspect and the third aspect.
  • the OLT, the ONU includes the ONU as described in the fourth aspect and any one of the possible implementations of the fourth aspect.
  • the OLT carries the start time t0 in the wavelength switching command sent to the ONU, and the OLT sends the downlink data directly to the ONU from the time t0, and does not need to wait for the ONU to confirm the completion of the wavelength switching message. After the ONU completes the wavelength switching, the communication is resumed at the first time, and the service interruption time during the wavelength switching is reduced.
  • Figure 1 is a schematic diagram of a network architecture of a TWDM-PON system
  • FIG. 2 is an interaction flowchart of Embodiment 1 of a wavelength switching method according to an embodiment of the present invention
  • FIG. 3 is an interaction flowchart of Embodiment 2 of a wavelength switching method according to an embodiment of the present invention
  • FIG. 4 is a schematic diagram of a PLOAM message format
  • FIG. 5 is a schematic structural diagram of an apparatus for wavelength switching according to an embodiment of the present invention
  • FIG. 6 is a schematic structural diagram of another apparatus for wavelength switching according to an embodiment of the present invention
  • Schematic diagram of the structure of the OLT
  • FIG. 8 is a schematic structural diagram of an ONU according to an embodiment of the present invention.
  • the technical solutions in the embodiments of the present invention are clearly and completely described in the following with reference to the accompanying drawings in the embodiments of the present invention. It is a partial embodiment of the invention, and not all of the embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative efforts are within the scope of the present invention.
  • the TWDM-PON system 100 includes an OLT 110, a plurality of ONUs 120, and an Optical Distribution Network (ODN) 130, wherein the OLT 110 passes the ODN 130 to point to A multi-point connection to multiple ONUs 120. More than one OLT may also be included in the TWDM-PON system 100.
  • a plurality of ONUs 120 share an optical transmission medium of the ODN130.
  • the ODN 130 may include a backbone fiber 131, an optical power split module 132, and a plurality of branch fibers 133.
  • the optical power splitting module 132 can be disposed at a remote node (N), which is connected to the OLT 110 through the trunk fiber 131 on the one hand, and to the plurality of ONUs 120 through the plurality of branch fibers 133 on the other hand.
  • the communication link between the OLT 110 and the plurality of ONUs 120 may include a plurality of wavelength channels, and the plurality of wavelength channels share the optical transmission medium of the ODN 130 by WDM.
  • Each ONU 120 can operate in one of the wavelength channels of the TWDM-PON system 100, and each wavelength channel can carry one or more services of the ONU 120. Also, the ONU120 operating in the same wavelength channel can share the wavelength channel by TDM.
  • the TWDM-PON system 100 has four wavelength channels as an example. It should be understood that, in practical applications, the number of wavelength channels of the TWDM-PON system 100 may also be determined according to network requirements.
  • the four wavelength channels of the TWDM-PON system 100 are respectively named as wavelength channel 1, wavelength channel 2, wavelength channel 3, and wavelength channel 4, wherein each wavelength channel adopts a pair of uplink and downlink wavelengths respectively.
  • the upstream wavelength and the downstream wavelength of the wavelength channel 1 may be ⁇ and ⁇ , respectively.
  • the upstream wavelength and the downstream wavelength of the wavelength channel 2 may be ⁇ 2 and ⁇ , respectively.
  • the upstream wavelength and the downstream wavelength of the wavelength channel 3 may be respectively For ⁇ 3 and ⁇
  • the upstream and downstream wavelengths of the wavelength channel 4 can be ⁇ 4 and ⁇ , respectively (14.
  • Each wavelength channel can have a corresponding wavelength channel identifier (for example, the channel number of the above four wavelength channels can be 1, 2, 3, 4), that is, the wavelength channel identifier has a matching relationship with the upstream and downstream wavelengths of the wavelength channel to which it is identified, and the OLT 110 and the ONU 120 can learn the upstream wavelength and the downstream wavelength of the wavelength channel according to the wavelength channel identifier.
  • the wavelength channel identifier for example, the channel number of the above four wavelength channels can be 1, 2, 3, 4
  • the OLT 110 may include an optical coupler 111, a first wavelength division multiplexer 112, and a second wavelength division multiplexer. 113, multiple downlink optical transmitters Txl ⁇ Tx4, multiple upstream optical receivers Rxl ⁇ Rx4 and processing module
  • the plurality of downstream optical transmitters Tx1 to Tx4 are connected to the optical coupler 111 through the first wavelength division multiplexer 112, and the plurality of upstream optical receivers Rx1 to Rx4 are connected to the optical coupler through the second wavelength division multiplexer 113.
  • the coupler 111 is further connected to the trunk fiber 131 of the ODN 130.
  • the emission wavelengths of the plurality of downlink optical transmitters Tx1 to Tx4 are different.
  • Each of the downstream optical transmitters Tx1 to Tx4 can respectively correspond to one of the wavelength channels of the TWDM-PON system 100, for example, multiple downlink optical transmitters Txl ⁇ .
  • the emission wavelength of Tx4 can be ⁇ (11 ⁇ (14.)
  • the downstream optical transmitters Txl ⁇ Tx4 can respectively use their emission wavelength ⁇ (11 ⁇ (14 will transmit downlink data to the corresponding wavelength channel, so as to be operated at the corresponding wavelength).
  • the receiving wavelengths of the plurality of uplink optical receivers Rx1 to Rx4 may be different, and each of the upstream optical receivers x1 to Rx4 also respectively correspond to one of the wavelength channels of the TWDM-PON system 100.
  • the receiving wavelengths of the plurality of upstream optical receivers Rxl ⁇ Rx4 may be respectively ⁇ 1 ⁇ 4.
  • the upstream optical receivers Rxl ⁇ Rx4 may receive the uplink data transmitted by the ONUs 120 operating in the corresponding wavelength channel by using the receiving wavelengths ⁇ 1 ⁇ 4, respectively.
  • the first wavelength division multiplexer 112 is configured to respectively transmit the wavelengths of the plurality of downlink optical transmitters Tx1 to Tx4 to ⁇ (11 ⁇ (14 downlink data is subjected to wavelength division multiplexing processing, and is sent to the optical coupler 111 through the optical coupler 111).
  • the backbone fiber 131 of the ODN 130 provides downlink data to the ONU 120 through the ODN 130.
  • the optocoupler 111 can also be used to provide uplink data from the plurality of ONUs 120 and having wavelengths of ⁇ 1 to ⁇ 4 to the second wavelength division multiplexer. 113.
  • the second wavelength division multiplexer 113 may demultiplex the uplink data having the wavelengths ⁇ to ⁇ 4 to the upstream optical receivers Rx1 to Rx4 for data reception.
  • the processing module 114 may be a Media Access Control (MAC) module, which may specify a working wavelength channel for the plurality of ONUs 120 by wavelength negotiation, and send the signal to be sent to the ONU 120 according to the working wavelength channel of the ONU 120.
  • the downlink data is provided to the downlink optical transmitters Tx1 to Tx4 corresponding to the wavelength channels, so that the downlink optical transmitters Tx1 to Tx4 transmit the downlink data to the corresponding wavelength channels.
  • the processing module 114 can also uplink the respective wavelength channels.
  • the Dynamic Bandwidth Allocation is configured to allocate an uplink transmission slot to the ONU 120 multiplexed to the same wavelength channel by the TDM mode, to authorize the ONU 120 to transmit uplink data through the corresponding wavelength channel in the designated time slot.
  • the uplink transmit wavelength and the downlink receive wavelength of each ONU 120 are adjustable, and the ONU 120 can respectively set its own uplink transmit wavelength and downlink receive wavelength according to the wavelength channel specified by the OLT 110.
  • the uplink wavelength and the downlink wavelength of the wavelength channel are adjusted, so that uplink and downlink data transmission and reception are performed through the wavelength channel.
  • the ONU 120 can adjust its own uplink transmit wavelength and downlink receive wavelength to the first uplink wavelength ⁇ and the first downlink wavelength ⁇ , respectively (11 ; If the OLT 110 instructs the ONU 120 to operate to the wavelength channel 3, the ONU 120 can adjust its own uplink transmission wavelength and downlink reception wavelength to the third uplink wavelength ⁇ 3 and the first downlink wavelength ⁇ , respectively.
  • the ONU 120 can include an optocoupler 121, a downstream optical receiver 122, an upstream optical transmitter 123, and a processing module 124.
  • the downstream optical receiver 122 and the upstream optical transmitter 123 are connected to the branch optical fiber 133 corresponding to the ONU 120 through the optical coupler 121.
  • the optical coupler 121 can provide the uplink data sent by the upstream optical transmitter 123 to the branch fiber 133 of the ODN 130 to be sent to the OLT 110 through the ODN 130.
  • the optical coupler 121 can also send the downlink data sent by the OLT 110 through the ODN 130.
  • the downlink optical receiver 122 is provided for data reception.
  • the processing module 124 can be a MAC module, which can perform wavelength negotiation with the OLT 110, and adjust the receiving wavelength of the downstream optical receiver 122 and the transmitting wavelength of the upstream optical transmitter 123 according to the wavelength channel specified by the OLT 110 (ie, adjusting the downlink receiving wavelength of the ONU 120). And the uplink transmit wavelength:), so that the ONU 120 operates in the wavelength channel specified by the OLT 110; in addition, the processing module 124 can also control the uplink optical transmitter 123 to send uplink data in the designated time slot according to the dynamic bandwidth allocation result of the OLT 110.
  • the number of ONUs 120 on the line is large, an ideal situation is that some ONUs 120 work in the wavelength channel 1, part of the operation in the wavelength channel 2, part of the operation in the wavelength channel 3, and part of the operation.
  • Wavelength channel 4, and the number of ONUs 120 of each wavelength channel is substantially equal.
  • the number of ONUs 120 per wavelength channel may be different due to the user moving up and down, etc., for example, there may be a large number of ONUs 120 of one wavelength channel, and another wavelength or wavelengths.
  • the number of ONUs 120 of the channel is small and there is no wavelength channel that is not used by the ONU 120, that is, the load of the wavelength channel is unbalanced.
  • Embodiment 1 the load of the wavelength channel used by the more ONUs is heavy.
  • the ONUs 120 operating in the same wavelength channel use TDM to perform service multiplexing.
  • bandwidth may be insufficient.
  • the normal service of the ONU 120 is affected.
  • the method for wavelength switching in the embodiment of the present invention can solve the problem that the OLT wavelength channel load is unbalanced. For details, refer to the following specific embodiments. Embodiment 1
  • FIG. 2 is an interaction flowchart of Embodiment 1 of a wavelength switching method according to an embodiment of the present invention. As shown in FIG. 2, the method in this embodiment includes:
  • Step S201 The OLT sends a wavelength switching command to the ONU.
  • the wavelength switching command sent by the OLT to the ONU is used to instruct the ONU to perform wavelength switching, and the wavelength switching command is used to instruct the ONU to switch from the source wavelength channel to the destination wavelength channel, where the wavelength switching command carries the starting time t0, which is used for Instructs the ONU to switch from the source wavelength channel to the destination wavelength channel at time t0.
  • the source wavelength channel and the destination wavelength channel herein only indicate any two channels that can work in the TWDM-PON system
  • the source wavelength channel indicates the wavelength channel in which the ONU is working
  • the destination wavelength channel indicates that the OLT indicates that the ONU switches to Wavelength channel.
  • the upstream and downstream wavelength pairs do not need to be uniquely paired, that is, the upstream wavelengths of the source wavelength channel and the destination wavelength channel may be the same wavelength, and the same source wavelength channel and purpose
  • the downstream wavelength of the wavelength channel can also be the same. That is to say, in this embodiment, the OLT may only instruct the ONU to perform uplink wavelength switching, or only perform downlink wavelength switching, or simultaneously perform uplink wavelength and downlink wavelength switching.
  • the OLT acquires a time T, which is a time required for the ONU to switch from the source wavelength channel to the destination wavelength channel.
  • Each wavelength channel includes a pair of wavelengths including an upstream wavelength and a downstream wavelength.
  • the source wavelength channel and the destination wavelength channel may have different uplink wavelengths, or only the downstream wavelengths may be different, or the uplink and downlink wavelengths may be different.
  • the time T may be the switching time of the corresponding uplink wavelength; when only the downlink wavelength is cut, the time T may be the switching time of the corresponding downlink wavelength; when the uplink and downlink wavelengths are simultaneously switched, the time T may be Refers to the longer one of the upstream wavelength switching time and the downstream wavelength switching time.
  • the switching of the upstream wavelength means that the emission wavelength of the laser is tuned by the corresponding control component, and the switching of the downstream wavelength may refer to controlling the filtering bandwidth or other filtering parameters of the tunable filter through the control component.
  • the switching of the uplink and downlink wavelengths is a prior art and will not be described in detail herein.
  • the switching time between different upstream wavelengths may be different, and the switching time between different downstream wavelengths may also be different. Therefore, the corresponding time T corresponds to the source wavelength channel and the destination wavelength channel, and the combination of each of the source wavelength channel and the destination wavelength channel corresponds to a corresponding time T.
  • the ONU needs to report the corresponding chirp, it can also report the source wavelength channel and the destination wavelength.
  • the OLT there are various methods for the OLT to obtain the time T required for the ONU to perform wavelength switching. For example, the ONU reports to the OLT during registration or registration, and the ONU switches from the source wavelength channel (may set its uplink and downlink wavelengths to ⁇ , ⁇ respectively) to the destination. The time required for the wavelength channel (may be set to ⁇ 2, ⁇ 2 for the upstream and downstream wavelengths respectively).
  • the OLT receives the wavelength switching information sent by the ONU, where the wavelength switching information carries the time T, and the OLT obtains the time ⁇ from the wavelength switching information.
  • the method is applicable to the ONU being the newly registered ONU, or the ONU is not saved in the OLT. The time required for wavelength switching.
  • the OLT can also read the time required for the ONU to perform wavelength switching from the local storage.
  • the time stored in the memory can be sent to the OLT before the ONU, or can be calculated by the OLT according to other information sent by the ONU. Or, it can be manually entered through the command line or the network management system.
  • the OLT allocates a destination wavelength channel to the ONU before sending the wavelength switching command to the ONU.
  • the OLT may need to instruct the ONU to perform wavelength switching during the operation of the ONU, for example, when the wavelength channel A is loaded.
  • the OLT can control a part of the ONUs that are working in the wavelength channel A to switch to the wavelength channel by adjusting the uplink transmission wavelength and/or the downlink reception wavelength by using a wavelength switching command.
  • the OLT allocates a destination wavelength channel to the ONU, and assigns any one of the plurality of idle wavelength channels to the ONU; or selects an optimal one of the wavelength channels to allocate to the ONU; Or, according to an algorithm, a certain wavelength channel is selected and allocated to the ONU.
  • the embodiment of the present invention does not limit how to select the destination wavelength channel.
  • the foregoing wavelength switching command may be sent during the ONU registration process, and may also be registered in the ONU and sent after being sent online.
  • Step S202 The ONU receives the wavelength switching command, and switches from the source wavelength channel to the destination wavelength channel at time t0.
  • the ONU after receiving the wavelength switching command sent by the OLT, the ONU performs wavelength switching according to the information in the wavelength switching command, and switches from the source wavelength channel to the destination wavelength channel.
  • the wavelength switching command is to instruct the ONU to switch the uplink wavelength and the downlink wavelength
  • the ONU needs to adjust its own optical receiver and optical transmitter to align the uplink wavelength and the downlink wavelength of the destination wavelength channel;
  • the command is to instruct the ONU to switch the upstream wavelength.
  • the ONU only needs to adjust its own optical transmitter to align the upstream wavelength.
  • the wavelength switching command indicates that the ONU switches the downstream wavelength, the ONU only needs to adjust itself.
  • An optical receiver to align the downstream wavelength.
  • the wavelength switching command transmitted by the OLT carries the start time t0, and the ONU starts the wavelength switching from the time t0.
  • the start time t0 is configured by the OLT, and the start time t0 may be any time after the ONU receives the wavelength switching command.
  • Step S203 The OLT sends downlink data to the ONU through the destination wavelength channel from the time t0, and the time T is the time required for the ONU to switch from the source wavelength channel to the destination wavelength channel.
  • the time T may be reported by the ONU to the OLT, or may be obtained by the OLT through configuration or external input or calculation.
  • the OLT should still send downlink data from the source wavelength channel and receive uplink data through the destination wavelength channel. If the OLT instructs the ONU to switch only the downlink wavelength, the OLT sends downlink data through the destination wavelength channel.
  • the ONU After switching to the destination wavelength channel, the ONU receives downlink data sent by the OLT through the destination wavelength channel.
  • the downlink data is directly sent to the ONU after the time T from the time t0, where the time T is the ONU.
  • the time T is the time required for the ONU to switch from the source wavelength channel to the destination wavelength channel
  • the ONU has switched to the destination wavelength channel after the time T from the time t0, and the downlink data sent by the OLT in the destination wavelength channel can be Received by the ONU. This completes the wavelength switching process.
  • the OLT sends the wavelength switching command carrying start time t0 to the ONU, and the interval time T from the time t0, the OTL sends the downlink data to the ONU, thereby saving the time for the wavelength switching confirmation between the OLT and the ONU, and reducing the wavelength.
  • FIG. 3 is an interaction flowchart of Embodiment 2 of a wavelength switching method according to an embodiment of the present invention. As shown in FIG. 3, the method in this embodiment includes:
  • Step S301 The OLT acquires a time T, where the time T is a time required for the ONU to switch from the source wavelength channel to the destination wavelength channel.
  • the OLT before the OLT sends a wavelength switching command to the ONU, the OLT first acquires the time T required for the wavelength switching by the ONU that needs to perform wavelength switching. This time is the time it takes for the ONU to switch from the source wavelength channel in operation to the destination wavelength channel that needs to be switched.
  • the OLT there are various methods for the OLT to obtain the time required for the ONU to perform wavelength switching. For example, the ONU reports to the OLT during registration or registration, and the ONU switches from the source wavelength channel (may set its uplink and downlink wavelengths to ⁇ , ⁇ respectively) to the destination. The time required for the wavelength channel (may be set to ⁇ 2, ⁇ 2 for the upstream and downstream wavelengths respectively).
  • the OLT receives the wavelength switching time message sent by the ONU, where the wavelength switching time message carries the time T, and the OLT obtains the time ⁇ from the wavelength switching time message, where the ⁇ is used to indicate the waiting time of the OLT, where The waiting time is the waiting time between the wavelength switching of the ONU and the downlink data sent by the OLT.
  • This method is applicable to the time required for the newly registered ONU or the OLT to save the ONU for wavelength switching. happening.
  • the ONU can report a, b, respectively. It is possible to report only the wavelength channel switching for the longest time b. Switching here refers to switching from the source wavelength pair to the destination wavelength pair, including the upstream wavelength and the downstream wavelength.
  • the OLT can also read the stored time T of the stored ONU for wavelength switching, and the time ⁇ stored in the memory can be sent to the OLT before the ONU, or can be calculated by the OLT according to other information sent by the ONU. Or, it can be manually entered through the command line or the network management system.
  • the ONU can pass the Physical Layer Operations Administration and Maintenance (PLOAM) message, the Optical Network Terminal Management and Control Interface (OMCI) message, and the Multipoint Control Protocol (Multi- Point Control Protocols, MPCP) Message or Operations Management and Maintenance (Operation Administration and Maintenance, OAM)
  • PLOAM Physical Layer Operations Administration and Maintenance
  • OMCI Optical Network Terminal Management and Control Interface
  • MPCP Multipoint Control Protocol
  • OAM Operations Management and Maintenance
  • the message carries any of the wavelength switching time messages sent by the ONU to the OLT.
  • the ONU may also carry the wavelength switching time information sent to the OLT through the newly defined message.
  • FIG. 4 is a schematic diagram of the PLOAM message format.
  • PLOAM messages typically include an Optical Network Unit Identification (ONU ID) field, a Message ID (Message ID) field, a Sequence Number field, a Data field, and an Integrity Check field.
  • ONU ID Optical Network Unit Identification
  • Message ID Message ID
  • Sequence Number a Sequence Number field
  • Data field a Data field
  • Integrity Check field an Integrity Check field.
  • the wavelength switching time information may be carried in a data field of a PLOAM message.
  • Step S302 the OLT determines to instruct the ONU to switch from the source wavelength channel to the destination wavelength channel. Specifically, before the OLT sends the wavelength switching command to the ONU, it is also required to determine whether the ONU needs to be switched from the source wavelength channel to the destination wavelength channel.
  • the OLT determines that the ONU switches from the source wavelength channel to the destination wavelength channel according to various situations, including: if the load of the source wavelength channel exceeds a preset overload threshold and the load of the destination wavelength channel does not exceed a preset overload a threshold, the OLT determines to indicate that the ONU is switched from the source wavelength channel to the destination wavelength channel; or if the load of the original wavelength channel is lower than a preset light load threshold and the load of the destination wavelength channel If the preset overload threshold is not exceeded, the OLT determines to indicate that the ONU switches from the source wavelength channel to the destination wavelength channel; or if the optical transceiver device corresponding to the source wavelength channel fails or the performance is lower than the pre- Setting a performance threshold, the OLT determines to instruct the ONU to switch from the source wavelength channel to the destination wavelength channel.
  • the OLT can detect the uplink and downlink traffic load of each wavelength channel in the TWDM-PON system in real time to determine whether wavelength switching is required.
  • the wavelength channel load imbalance of the TWDM-PON system for example, when the downlink load of the wavelength channel 1 is too heavy, the downlink load of the wavelength channel 2 is light, and when the downlink load of the wavelength channels 3 and 4 is normal, the OLT can determine the need. Indicates that the ONU that is working in the wavelength channel 1 switches to the wavelength channel 2 for downlink service reception. That is, the OLT can determine that the ONU needs to instruct the ONU to switch its downlink receiving wavelength from the downstream wavelength of the wavelength channel 1 to the downstream of the wavelength channel 2. wavelength.
  • the OLT may also be required for energy saving or optical transceiver replacement.
  • the OLT can determine if you need to indicate ONU Perform wavelength switching. For example, when the OLT detects that only a very small number of ONUs are working in a certain wavelength channel, and other wavelength channels still have bandwidth resources, the OLT can determine that the ONU needs to be instructed to switch from the original wavelength channel to the bandwidth resource based on the energy saving requirement. The wavelength channel and the original wavelength channel are turned off to reduce the overall power consumption of the TWDM-PON system and achieve energy saving.
  • the OLT when the OLT detects that a certain optical transceiver device (such as a downlink optical transmitter or an upstream optical receiver) is faulty or has performance degradation, it may be determined that the ONU that needs to indicate the original wavelength operation in the optical transceiver device is switched to Other wavelength channels perform service transmission and reception to avoid normal services due to optical transceiver failure or performance degradation, and maintenance personnel can replace optical transceivers with faults or performance degradation.
  • the OLT can also indicate that the ONU switches back to the original working channel as needed.
  • step S301 and step S302 are not sequential, and step S301 and step S302 may also be performed simultaneously.
  • Step S303 The OLT sends a wavelength switching command to the ONU.
  • the wavelength switching command is used to indicate that the ONU is switched from the source wavelength channel to the destination wavelength channel, where the wavelength switching command carries a start time t0, and is used to indicate that the ONU starts from the source at the time of to The wavelength channel is switched to the destination wavelength channel.
  • the wavelength switching command carries the identifier of the destination wavelength channel; or carries the uplink wavelength and/or the downlink wavelength of the destination wavelength channel; or carries the identifier of the destination wavelength channel or the uplink wavelength and/or the downlink wavelength of the destination wavelength channel, and the wavelength Switching type information, the wavelength switching type information is used to indicate switching uplink wavelengths and/or downlink wavelengths.
  • the ONU may determine the destination wavelength channel that needs to be switched according to the identification information of the destination wavelength channel or the destination uplink wavelength and/or the destination downlink wavelength that needs to be switched. Therefore, the wavelength switching command sent by the OLT to the ONU includes the identification information of the destination wavelength channel or the destination upstream wavelength and/or the destination downstream wavelength in the destination wavelength channel. In addition, the wavelength switching command may further include a wavelength switching type information, where the wavelength switching type information is used to indicate that the ONU performs the switching of the uplink and downlink wavelengths simultaneously, or only the uplink wavelength or the downlink wavelength is switched.
  • the OLT may send a wavelength switching command to the ONU through one of a PLOAM message, an OMCI message, an MPCP message, or an OAM message.
  • the specific message format such as the field value and the field length, may be determined according to actual needs.
  • the OLT may also send a wavelength switching command to the ONU through the newly defined message bearer.
  • the message format of the PLOAM message is shown in FIG. 4, and FIG. 4 is a schematic diagram of the PLOAM message format.
  • the PLOAM message typically includes an Optical Network Unit Identity (ONU ID) field, a Message ID field, a Sequence No field, a Data field, and an Integrity Check field.
  • the wavelength switching type information and the wavelength switching related information such as the target wavelength channel identifier information or the target downlink receiving wavelength information may be carried in the data field of the PLOAM message.
  • the wavelength switching command may be as shown in Table 1. format.
  • the wavelength switching time information sent by the ONU to the OLT may also adopt a message format similar to the message format shown in FIG. 4 and Table 1.
  • the start time t0 carried by the wavelength switching command may be the time when the OLT receives the wavelength switching acknowledgement message sent by the ONU, or the time t0 is the time when the ONU receives the wavelength switching command.
  • the OLT can also receive the wavelength switching confirmation message sent by the ONU, so that the OLT knows that the ONU has received the wavelength switching command, and can start wavelength switching. Therefore, the time t0 carried by the OLT to the wavelength switching command sent by the ONU can be set to the time when the OLT receives the wavelength switching confirmation message sent by the ONU. That is to say, the meaning of the time t0 set by the OLT is that after the OLT receives the wavelength switching confirmation message sent by the ONU, it confirms that the ONU can perform wavelength switching, and then causes the ONU to start wavelength switching, thereby ensuring the interval of the OLT from time t0.
  • the downlink data sent after time T can be received by the ONU, thereby improving the reliability of the system.
  • the OLT may not wait to receive the ONU after sending the wavelength switching command to the ONU.
  • the wavelength switching confirmation message that is, the time t0 is set to the time when the ONU receives the wavelength switching command. This applies to the high-urgency wavelength switching requirement.
  • the OLT considers that the ONU receives the wavelength switching command, it starts to send downlink data to the ONU in the destination wavelength channel, which can shorten the time required for wavelength switching.
  • Step S304 The ONU switches from the source wavelength channel to the destination wavelength channel at time t0.
  • the OLT starts a "wavelength switching" timer at time t0 to start timing for recording the time of wavelength switching.
  • Step S305 The OLT sends the downlink data and the uplink time slot authorization to the ONU through the destination wavelength channel from the time t0, and the time T is the time required for the ONU to switch from the source wavelength channel to the destination wavelength channel.
  • the OLT passes the time T through the destination wavelength channel from time t0. While transmitting the downlink data, the ONU also sends an uplink time slot grant to the ONU. That is, the OLT needs to instruct the ONU to use the upstream time slot of the destination wavelength channel. For the WDM system, if the wavelength switching method of this embodiment is adopted, the OLT does not need to want the ONU to send an uplink time slot grant.
  • Step S306 the OLT stores the downlink data in the local storage.
  • the OLT After the OLT sends the downlink data and the uplink time slot authorization to the ONU in the destination wavelength channel, the OLT also stores the downlink data in the local memory. After the OLT sends a wavelength switching command to the ONU, the OLT has not received the handover completion message sent by the ONU. That is, the OLT has not confirmed that the ONU has completed the wavelength switching. The ONU may not be completed due to channel error or ONU failure. The wavelength is switched. Therefore, in order to ensure the integrity of the service, the OLT stores the downlink data in the local storage after the destination wavelength channel grants the ONU downlink data and the uplink time slot.
  • step S306 can be performed simultaneously with step S305.
  • the OLT transmits the downlink data only on the destination wavelength channel of the ONU, and performs bandwidth authorization, that is, performs dynamic bandwidth allocation (Danannc Bandwidth Allocation (DBA) scheduling according to the service condition on the destination wavelength channel, and authorizes the ONU to send uplink transmission.
  • DBA Dynamic Bandwidth Allocation
  • the OLT will save the data sent to the ONU on the destination wavelength channel in the local storage.
  • the uplink data sent by the ONU on the OLT authorized time slot or the "wavelength switching completed" message reported by the ONU is received.
  • the optical line terminal OLT can also prepare the MAC (Media Access Control) layer of the destination wavelength channel to prepare the data transmission for the ONU on the destination wavelength channel before the ONU completes the wavelength switching, for example.
  • Prepare a new routing forwarding table for the ONU in the MAC layer of the destination wavelength channel prepare the downlink data of the ONU in advance, and calculate the time slot authorization of the ONU, so that the new channel of the OLT can just complete the wavelength switching in the ONU.
  • the downlink data and the uplink time slot grant can be sent to the destination wavelength channel at any time.
  • Step S307 After completing the wavelength adjustment, the ONU receives the downlink data of the OLT on the destination wavelength channel, and sends the uplink data to the OLT in the time slot authorized by the OLT according to the uplink authorization information of the ONU in the downlink data.
  • the ONU can receive the downlink data and the uplink time slot grant sent by the OLT.
  • the OLT sends the downlink data and the uplink time slot authorization to the ONU after the destination wavelength channel. If the ONU normally receives the downlink data, the ONU will send the wavelength switch to the OLT in the destination wavelength channel. Message. This allows the OLT to confirm that the ONU has switched to the destination wavelength channel.
  • the ONU may send an "ONU Wavelength Switching Complete Confirmation" message to the uplink data sent by the OLT to inform the uplink wavelength switching that the handover has been successful.
  • the wavelength switch completion confirmation may also be carried by a PLOAM message, an OMCI message, an MPCP message, an OAM message, or other newly defined message.
  • the ONU in order to prevent the ONU from switching in the uplink wavelength, the ONU itself fails to know the fault, and the uplink wavelength is switched to the non-destination uplink wavelength, and then the non-destination uplink wavelength is used to transmit to the OLT by using the destination uplink wavelength slot.
  • Uplink data and messages causing interference to other wavelength channels.
  • the OLT instructs the ONU to switch the upstream wavelength from ⁇ to ⁇ 2.
  • the transmitter mis-adjusts the emission wavelength to the passband of ⁇ 3 or other channel wavelengths, which will cause the ONU to ⁇ 3 sends uplink data in the authorized time slot of the wavelength channel corresponding to ⁇ 2, which interferes with the communication of the ONU working normally on ⁇ 3.
  • the OLT transmits the downlink data and the uplink time slot grant to the ONU from the time t0, the interval time T, optionally, the OLT pre-stages the uplink time slot on the other multiple wavelength channels. Leave it and authorize it to the ONU to prevent the ONU from transmitting data at its wavelength in this time slot, thus interfering with other ONUs on other channels. That is, the OLT allocates the same uplink time slot to the ONU in multiple wavelength channels. At this time, on all wavelength channels, the uplink time slot is only allocated to the ONU.
  • the OLT After the OLT receives the uplink data or the wavelength switch completion message sent by the ONU in the destination wavelength channel, it confirms that the ONU has switched to the destination wavelength channel. At this time, the OLT stops the uplink in the other wavelength channels except the destination wavelength and the uplink time slot authorization. Authorization of the ONU by the uplink time slot corresponding to the time slot. This can further improve system reliability and prevent ONU switching from affecting other ONUs.
  • Step S308 after receiving the uplink data or the handover complete message sent by the ONU, the OLT stops storing the downlink data in the local memory, and releases the downlink data stored in the local memory, and stops the wavelength switching timer, and stops the wavelength switching timer. The recorded time is cleared.
  • the OLT can release the downlink data stored in the local memory.
  • the triggering condition for the OLT to release the downlink data stored in the local storage may be: when the OLT receives the uplink data sent by the ONU in the destination wavelength channel.
  • the OLT can also confirm that the ONU has completed the wavelength switching, so that the downlink data stored in the local memory can be released.
  • the OLT further includes: the OLT sends a wavelength switch completion confirmation message to the ONU. After confirming that the ONU completes the wavelength switching, the OLT can also notify the ONU that the confirmation message of the wavelength switching has been completed.
  • the OLT further includes: after the preset time of the preset wavelength switching, the OLT does not receive the uplink data sent by the ONU in the destination wavelength channel or When the wavelength switching completion message is received, the OLT passes through the source wavelength.
  • the channel sends the downlink data stored in the local storage to the ONU, or the OLT retransmits the downlink data stored in the local storage to the ONU after the OLT resumes the communication channel with the ONU.
  • a wavelength switching timer is set in the OLT. After the OLT sends a wavelength switching command to the ONU, the OLT starts the wavelength switching timer, and the OLT receives the uplink data sent by the ONU before the wavelength switching timer expires.
  • the wavelength switching completion message indicates that the ONU has completed wavelength switching. After the OLT sends the downlink data and the uplink time slot authorization to the ONU in the destination wavelength channel, and after the preset wavelength switching timing time (that is, after the wavelength timer expires), the OLT still does not receive the uplink data sent by the ONU on the destination wavelength channel or When the wavelength switching completion message is received, the OLT will determine that the wavelength switching of the ONU has failed.
  • the OLT will wait for the ONU to roll back to the source wavelength channel, and send the downlink data stored in the local storage to the ONU on the source wavelength channel. Or the OLT resends the downlink data stored in the local memory to the ONU after the OLT restores the communication channel with the ONU.
  • the OLT When the OLT does not receive the uplink data or the wavelength switch completion message sent by the ONU in the destination wavelength channel after the preset wavelength switching time, the OLT sends the local memory to the ONU in the source wavelength channel after the ONU falls back to the source wavelength channel.
  • wavelength switching method provided in this embodiment is applicable not only to the TWDM-PON system but also to an optical communication system having multiple wavelengths such as a WDM-PON system.
  • FIG. 5 is a schematic structural diagram of an apparatus for wavelength switching according to an embodiment of the present invention. As shown in FIG. 5, the apparatus 50 for wavelength switching provided by this embodiment includes:
  • the processing unit 51 is configured to generate a wavelength switching command, and instruct to send the wavelength switching command to the ONU, where the wavelength switching command is used to instruct the ONU to switch from the source wavelength channel to the destination wavelength channel, where the wavelength switching command Carrying a start time t0, the t0 is used to indicate that the ONU starts to switch from the source wavelength channel to the destination wavelength channel at the time of to; and is further configured to indicate that the time T is elapsed from the time t0, start Transmitting downlink data to the ONU through the destination wavelength channel.
  • the device further includes:
  • the sending unit 52 is configured to send a wavelength switching command to the ONU according to the indication of the processing unit;
  • the time T is sent to the ONU through the destination wavelength channel, and the time T is the time required for the ONU to switch from the source wavelength channel to the destination wavelength channel. .
  • the wavelength switching command is used to indicate that the ONU is switched from the source wavelength channel to the destination wavelength channel, where the wavelength switching command carries a start time t0, and is used to indicate that the ONU starts from the source at the time of to The wavelength channel is switched to the destination wavelength channel.
  • the wavelength switching command carries the identifier of the destination wavelength channel; or carries the uplink wavelength and/or the downlink wavelength of the destination wavelength channel; or carries the identifier of the destination wavelength channel or the uplink wavelength and/or the downlink wavelength of the destination wavelength channel, and the wavelength Switching type information, the wavelength switching type information is used to indicate switching uplink wavelengths and/or downlink wavelengths.
  • the ONU may determine the destination wavelength channel that needs to be switched according to the identification information of the destination wavelength channel or the destination uplink wavelength and/or the destination downlink wavelength that needs to be switched. Therefore, the wavelength switching command sent by the OLT to the ONU includes the identification information of the destination wavelength channel or the destination upstream wavelength and/or the destination downstream wavelength in the destination wavelength channel. In addition, the wavelength switching command may further include a wavelength switching type information, where the wavelength switching type information is used to indicate that the ONU performs the switching of the uplink and downlink wavelengths simultaneously, or only the uplink wavelength or the downlink wavelength is switched.
  • the OLT may send a wavelength switching command to the ONU through one of a PLOAM message, an OMCI message, an MPCP message, or an OAM message.
  • the specific message format such as the field value and the field length, may be determined according to actual needs.
  • the OLT may also send a wavelength switching command to the ONU through the newly defined message bearer.
  • FIG. 4 is a schematic diagram of the PLOAM message format.
  • the PLOAM message typically includes an Optical Network Unit Identity (ONU ID) field, a Message ID field, a Sequence No field, a Data field, and an Integrity Check field.
  • ONU ID Optical Network Unit Identity
  • Message ID field a Message ID field
  • Sequence No field a Sequence No field
  • Data field a Data field
  • Integrity Check field an Integrity Check field.
  • the wavelength switching type information and the wavelength switching related information such as the target wavelength channel identifier information or the target downlink receiving wavelength information may be carried in the data field of the PLOAM message.
  • the wavelength switching command may be as shown in Table 1. format.
  • the device for wavelength switching in this embodiment is used to perform the technical solution on the OLT side in the first embodiment, and the implementation principle and technical effects are similar, and details are not described herein again.
  • the device 50 for wavelength switching further includes: a receiving unit 53, configured to acquire the Time ⁇ .
  • the OLT there are various methods for the OLT to obtain the time T required for the ONU to perform wavelength switching. For example, the ONU reports to the OLT during registration or registration, and the ONU switches from the source wavelength channel (may set its uplink and downlink wavelengths to ⁇ , ⁇ respectively) to the destination. The time required for the wavelength channel (may be set to ⁇ 2, ⁇ 2 for the upstream and downstream wavelengths respectively).
  • the OLT receives the wavelength switching time message sent by the ONU, where the wavelength switching time message carries the time T, and the OLT obtains the time ⁇ from the wavelength switching time message.
  • the method is applicable to the newly registered ONU or the OLT does not save the ONU.
  • the OLT can also read the time required for the ONU to perform wavelength switching from the local storage.
  • the time stored in the memory can be sent to the OLT before the ONU, or can be calculated by the OLT according to other information sent by the ONU. Or, it can be manually entered through the command line or the network management system.
  • the ONU can pass the Physical Layer Operations Administration and Maintenance (PLOAM) message, the Optical Network Terminal Management and Control Interface (OMCI) message, and the Multipoint Control Protocol (Multi- The Point Control Protocols (MPCP) message or any of the Operation Management and Maintenance (OAM) messages carries the wavelength switch time message sent by the ONU to the OLT.
  • PLOAM Physical Layer Operations Administration and Maintenance
  • OMCI Optical Network Terminal Management and Control Interface
  • MPCP Multipoint Control Protocol
  • OAM Operation Management and Maintenance
  • the ONU may also carry the wavelength switching time information sent to the OLT through the newly defined message.
  • FIG. 4 is a schematic diagram of the PLOAM message format.
  • PLOAM messages typically include an Optical Network Unit Identification (ONU ID) field, a Message ID (Message ID) field, a Sequence Number field, a Data field, and an Integrity Check field.
  • ONU ID Optical Network Unit Identification
  • Message ID Message ID
  • Sequence Number a Sequence Number field
  • Data field a Data field
  • Integrity Check field an Integrity Check field.
  • the wavelength switching time information may be carried in a data field of a PLOAM message.
  • the device 50 for wavelength switching further includes: a storage unit 54 configured to store the downlink data in the local storage.
  • the processing unit 51 is further configured to determine that the ONU is switched from the source wavelength channel to the destination wavelength channel. Specifically, before the OLT sends the wavelength switching command to the ONU, it is also required to determine whether the ONU needs to be switched from the source wavelength channel to the destination wavelength channel.
  • the OLT determines that the ONU switches from the source wavelength channel to the destination wavelength channel according to various situations, including: if the load of the source wavelength channel exceeds a preset overload threshold and the load of the destination wavelength channel does not exceed a preset overload a threshold, the OLT determines to indicate that the ONU is switched from the source wavelength channel to the destination wavelength channel; or if the load of the original wavelength channel is lower than a preset light load threshold and the load of the destination wavelength channel If the preset overload threshold is not exceeded, the OLT determines to indicate that the ONU switches from the source wavelength channel to the destination wavelength channel; or if the optical transceiver device corresponding to the source wavelength channel fails or the performance is lower than the pre- Setting a performance threshold, the OLT determines to instruct the ONU to switch from the source wavelength channel to the destination wavelength channel.
  • the OLT can detect the uplink and downlink traffic load of each wavelength channel in the TWDM-PON system in real time to determine whether wavelength switching is required.
  • the wavelength channel load imbalance of the TWDM-PON system for example, when the downlink load of the wavelength channel 1 is too heavy, the downlink load of the wavelength channel 2 is light, and when the downlink load of the wavelength channels 3 and 4 is normal, the OLT can determine the need. Indicates that the ONU that is working in the wavelength channel 1 switches to the wavelength channel 2 for downlink service reception. That is, the OLT can determine that the ONU needs to instruct the ONU to switch its downlink receiving wavelength from the downstream wavelength of the wavelength channel 1 to the downstream of the wavelength channel 2. wavelength.
  • the OLT may also be required for energy saving or optical transceiver replacement.
  • the OLT can determine if the ONU needs to be instructed to perform wavelength switching. For example, when the OLT detects that only a very small number of ONUs are working in a certain wavelength channel, and other wavelength channels still have bandwidth resources, the OLT can determine that the ONU needs to be instructed to switch from the original wavelength channel to the bandwidth resource based on the energy saving requirement.
  • the wavelength channel and the original wavelength channel are turned off to reduce the overall power consumption of the TWDM-PON system and achieve energy saving.
  • the OLT when the OLT detects that a certain optical transceiver device (such as a downlink optical transmitter or an upstream optical receiver) is faulty or has performance degradation, it may be determined that the ONU that needs to indicate the original wavelength operation in the optical transceiver device is switched to Other wavelength channels perform service transmission and reception to avoid normal services due to optical transceiver failure or performance degradation, and maintenance personnel can replace optical transceivers with faults or performance degradation.
  • the OLT can also instruct the ONU to switch back to the original working channel as needed.
  • the processing unit 51 is further configured to: when the OLT receives the uplink data or the wavelength switch completion message sent by the ONU in the destination wavelength channel, release the downlink data stored in the local memory.
  • the sending unit 52 is further configured to: when the OLT does not receive the uplink data or the wavelength switching complete message sent by the ONU in the destination wavelength channel after the preset wavelength switching timing time, After the ONU falls back to the source wavelength channel, the downlink data stored in the local memory is sent to the ONU in the source wavelength channel, or the wavelength re-registered in the ONU after the ONU is re-registered. The downlink data stored in the local storage is retransmitted to the ONU on the channel.
  • the sending unit 52 is further configured to send an uplink time slot authorization to the ONU by using the destination wavelength channel after the time T from the time t0.
  • the wavelength switching command carries an identifier of the destination wavelength channel or an uplink wavelength and/or a downlink wavelength of the destination wavelength channel; or the wavelength switching command carries the The identifier of the destination wavelength channel or the uplink wavelength and/or the downlink wavelength of the destination wavelength channel, and the wavelength switching type information, where the wavelength switching type information includes indication information for switching the uplink wavelength and/or the downlink wavelength.
  • FIG. 6 is a schematic structural diagram of another apparatus for wavelength switching according to an embodiment of the present invention. As shown in FIG. 6, the apparatus 60 for wavelength switching provided by this embodiment includes:
  • the sending unit 61 is configured to send a wavelength switching time message to the OLT, where the wavelength switching time message carries a time T, where the time T is a time required for the ONU to switch from the source wavelength channel to the destination wavelength channel, where the T is used to indicate the location
  • the waiting time of the OLT is the waiting time between the wavelength switching from the ONU and the downlink data sent by the OLT.
  • the receiving unit 63 is configured to receive a wavelength switching command sent by the OLT, where the wavelength switching command is used to instruct the ONU to switch from the source wavelength channel to the destination wavelength channel, where the wavelength switching command carries a starting time t0, and is used to indicate the The ONU starts to switch from the source wavelength channel to the destination wavelength channel at time t0;
  • the processing unit 62 is configured to switch from the source wavelength channel to the destination wavelength channel at the time t0;
  • the receiving unit 63 is further configured to pass the target wavelength after switching to the destination wavelength channel
  • the channel receives downlink data sent by the OLT.
  • the device for wavelength switching in this embodiment is used to perform the technical solution on the ONU side in the first embodiment, and the implementation principle and technical effects are similar, and details are not described herein again.
  • the receiving unit 63 is further configured to receive, by using the time T from the time t0, the uplink time slot authorization sent by the OLT by using the destination wavelength channel.
  • the wavelength switching command carries an identifier of the destination wavelength channel or an uplink wavelength and/or a downlink wavelength of the destination wavelength channel; or the wavelength switching command carries the The identifier of the destination wavelength channel or the uplink wavelength and/or the downlink wavelength of the destination wavelength channel, and the wavelength switching type information, where the wavelength switching type information includes indication information for switching the uplink wavelength and/or the downlink wavelength.
  • FIG. 7 is a schematic structural diagram of an OLT according to an embodiment of the present invention.
  • the OLT 70 provided in this embodiment includes an optical coupler 71 and a first wave.
  • the optical coupler 71, the first wavelength division multiplexer 72, the second wavelength division multiplexer 73, the plurality of downlink optical transmitters Tx1 to Tx4, and the plurality of upstream optical receivers Rx1 to Rx4 are as shown in FIG.
  • the corresponding modules in the OLT 110 are similar, and the processor 74 can be used to perform the method on the OLT side as in the first or second embodiment.
  • FIG. 8 is a schematic structural diagram of an ONU according to an embodiment of the present invention.
  • the ONU 80 provided in this embodiment includes an optical coupler 81 and downlink optical reception.
  • the transmitter 82, the upstream light transmitter 83 and the processor 84 are similar to the corresponding modules in the ONU 120 shown in FIG. 1.
  • the processor 84 can be used to perform the method on the ONU side as in the first embodiment or the second embodiment. .
  • the embodiment of the present invention further discloses a passive optical network system, including an OLT and an ONU.
  • the OLT connects at least one ONU through an ODN.
  • the OLT includes an OLT as shown in FIG. 7, and the ONU includes an ONU as shown in FIG.
  • G/E-PON and 10G-PON are taken as an example, but the invention is not limited thereto.
  • a single channel 40G-PON and 100G-PON may appear in the network.
  • the technical solution of the present invention can also be used to implement coexistence of ONUs of multiple protocols and multiple rates, and details are not described herein again.
  • aspects of the present invention, or possible implementations of various aspects can be embodied as a system, method, or computer program product.
  • aspects of the invention, or possible implementations of various aspects may take the form of an entirely hardware embodiment, an entirely software embodiment (including firmware, resident software, etc.), or a combination of software and hardware aspects, They are collectively referred to herein as "circuits," “modules,” or “systems.”
  • the corresponding processing unit may be a corresponding processor, or a field programmable integer column FPGA, or may be an integrated circuit ASIC, or a combination of a processor and a memory, or a corresponding integrated chip.
  • the corresponding transmitting or receiving unit may be an optical transmitter or an optical receiver, or an optical transceiver incorporating a light transmitting or light receiving function.
  • aspects of the invention, or possible implementations of various aspects may take the form of a computer program product, which is a computer readable program code stored on a computer readable medium.
  • the computer readable medium can be a computer readable signal medium or a computer readable storage medium.
  • the computer readable storage medium includes, but is not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, device, or device, or any suitable combination of the foregoing, such as random access memory RAM:), read only memory (ROM:), Erasable programmable read-only memory (EPROM or flash memory:), optical fiber, portable read-only memory (CD-ROM:).
  • the processor in the computer reads the computer readable program code stored in the computer readable medium, such that the processor can perform the functional actions specified in each of the steps, or combinations of steps in the flowchart; A device for functional operation specified in each block of the block diagram or in a combination of blocks.
  • the computer readable program code can be executed entirely on the user's computer, partly on the user's computer, as a separate software package, partly on the user's computer and partly on the remote computer, or entirely on the remote computer or server.
  • the functions noted in the various blocks of the flowchart, or in the block diagrams may not occur in the order noted. For example, depending on the functionality involved, two steps, or two blocks, shown in succession may actually be performed substantially concurrently, or the blocks may sometimes be executed in the reverse order.

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Abstract

A wavelength switching method, device and system, the wavelength switching method comprising: an OLT (110) transmits a wavelength switching command to an ONU (120), the wavelength switching command being used to indicate that the ONU (110) switches from a source wavelength channel to a target wavelength channel, and the wavelength switching command carrying a start time t0, t0 being used to indicate that the ONU starts to switch from the source wavelength channel to the target wavelength channel at t0; the OLT (110) starts to transmit downlink data to the ONU (120) via the target wavelength channel during the time T starting from t0, the time T being the time required by the ONU (120) to switch from the source wavelength channel to the target wavelength channel. The wavelength switching method, device and system are used to shorten the time required for wavelength switching.

Description

波长切换方法、 装置和*** 技术领域  Wavelength switching method, device and system
本发明实施例涉及光通信技术， 尤其涉及一种波长切换方法、 装置和系 统。 背景技术  Embodiments of the present invention relate to optical communication technologies, and in particular, to a wavelength switching method, apparatus, and system. Background technique
无源光网络 （Passive Optical Network, PON) 技术是目前一种主要的宽 带接入技术。 为了解决传统的时分复用 （Time Division Multiplexing, TDM) PON收 TDM机制的影响， 带宽通常会收到限制的问题， 业界提出了融合波 分复用 （Wave Division Multiplexing, WDM) 技术和 TDM技术的时分 -波分 复用 （Time Wave Division Multiplexing, TWDM) PON***。  Passive Optical Network (PON) technology is currently a major broadband access technology. In order to solve the problem of the traditional Time Division Multiplexing (TDM) PON receiving TDM mechanism, the bandwidth is usually limited. The industry has proposed Wave Division Multiplexing (WDM) technology and TDM technology. Time Wave Division Multiplexing (TWDM) PON system.
TWDM PON***是一种点对多点的通信***， 其中局端的光线路终端 (Optical Line Terminal, OLT)与用户侧的光网络单元（Optical Network Unit, ONU) 之间采用多个波长通道进行数据收发， 每个 ONU分别工作在其中的 一个波长通道。 在下行方向， OLT采用每一个波长通道分别对应的下行波长 将下行数据广播给工作在该波长通道的多个 ONU; 在上行方向， 每一个波长 通道的 ONU可以在 OLT分配的时隙中采用该波长通道的上行波长向 OLT发 送上行数据。  The TWDM PON system is a point-to-multipoint communication system. The optical line terminal (OLT) at the central office and the optical network unit (ONU) on the user side use multiple wavelength channels for data. Transceiver, each ONU operates in one of the wavelength channels. In the downlink direction, the OLT uses the downlink wavelength corresponding to each wavelength channel to broadcast downlink data to multiple ONUs working in the wavelength channel. In the uplink direction, the ONU of each wavelength channel can adopt the time slot allocated by the OLT. The upstream wavelength of the wavelength channel sends uplink data to the OLT.
在实际应用中， 为了实现 TWDM PON***各个波长通道的负载均衡， 可以对 ONU所使用的下行波长和上行波长进行动态调整。 当 OLT发现某一 波长通道的负载过大时， 可以向工作在该波长通道的 ONU发送波长切换指 令， 指示 ONU通过调整其上行波长和 /或下行波长以切换到负载较轻的波长 通道。  In practical applications, in order to achieve load balancing of each wavelength channel of the TWDM PON system, the downlink wavelength and the uplink wavelength used by the ONU can be dynamically adjusted. When the OLT finds that the load of a certain wavelength channel is too large, it can send a wavelength switching instruction to the ONU working in the wavelength channel, instructing the ONU to switch to the lighter wavelength channel by adjusting its upstream wavelength and/or downstream wavelength.
但在目前的 TWDM PON***中，在进行某一个 ONU的波长切换过程中， OLT需要先向该 ONU发送波长切换指令， ONU收到波长调谐指令后开始进 行波长切换， OLT在等待 ONU完成波长切换的过程中， 会不断地向 ONU发 送是否完成切换的询问命令， 当 ONU完成波长切换后， 向 OLT发送已经完 成波长切换的消息， OLT接收到 ONU发送的已经完成波长切换的消息后， 再开始向 ONU发送下行数据、上行数据的时隙授权等信息，从而 OLT和 ONU 才能恢复正常业务通信。 However, in the current TWDM PON system, during the wavelength switching process of an ONU, the OLT needs to first send a wavelength switching command to the ONU, and the ONU starts to perform wavelength switching after receiving the wavelength tuning command, and the OLT waits for the ONU to complete the wavelength switching. During the process, the ONU is continuously sent an inquiry command to complete the handover. After the ONU completes the wavelength switching, the ONU sends a message that the wavelength switching has been completed to the OLT. After receiving the message that the ONU has completed the wavelength switching, the OLT receives the message. Then, the information such as the downlink data and the time slot authorization of the uplink data is sent to the ONU, so that the OLT and the ONU can resume normal service communication.
现有的 TWDM PON***中， 在波长切换过程中， OLT需要不断向 ONU 发送询问命令，直到收到 ONU发送的表明已经完成波长切换的消息才重新开 始重新传输业务数据， 导致业务中断时间较长。 发明内容  In the existing TWDM PON system, during the wavelength switching process, the OLT needs to continuously send an inquiry command to the ONU until the message sent by the ONU indicating that the wavelength switching has been completed is restarted to re-transmit the service data, resulting in a long service interruption time. . Summary of the invention
本发明实施例提供一种波长切换方法、 装置和***， 用于解决现有技术 中进行波长切换操作时， 由于 OLT和 ONU反复信息交互导致业务中断时间 过长的技术问题。  The embodiment of the invention provides a wavelength switching method, device and system, which are used to solve the technical problem that the service interruption time is too long due to the repeated information interaction between the OLT and the ONU in the wavelength switching operation in the prior art.
第一方面提供一种波长切换方法， 包括：  The first aspect provides a wavelength switching method, including:
OLT向 ONU发送波长切换命令， 所述波长切换命令用于指示所述 ONU 从源波长通道切换到目的波长通道， 其中， 所述波长切换命令携带开始时刻 t0， 所述 t0用于指示所述 ONU在 t0时刻开始从所述源波长通道切换到所述 目的波长通道；  The OLT sends a wavelength switching command to the ONU, where the wavelength switching command is used to instruct the ONU to switch from the source wavelength channel to the destination wavelength channel, where the wavelength switching command carries a start time t0, where the t0 is used to indicate the ONU Switching from the source wavelength channel to the target wavelength channel at time t0;
所述 OLT从所述 t0时刻起经过时间 T的时刻， 开始通过所述目的波长 通道向所述 ONU发送下行数据， 其中， 所述时间 T为所述 ONU从所述源波 长通道切换到所述目的波长通道所需时间。  The OLT starts to send downlink data to the ONU through the destination wavelength channel, and the time T is that the ONU switches from the source wavelength channel to the The time required for the destination wavelength channel.
在第一方面第一种可能的实现方式中， 所述 OLT向 ONU发送所述波长 切换命令之前， 还包括：  In a first possible implementation manner of the first aspect, before the sending, by the OLT, the wavelength switching command to the ONU, the method further includes:
所述 OLT获取所述 ONU上报的所述时间 T。  The OLT acquires the time T reported by the ONU.
结合第一方面或第一方面第一种可能的实现方式， 在第二种可能的实现 方式中， 所述波长切换命令携带所述目的波长通道的标识； 或携带所述目的 波长通道的上行波长和 /或下行波长。  With reference to the first aspect or the first possible implementation manner of the first aspect, in a second possible implementation, the wavelength switching command carries an identifier of the destination wavelength channel; or carries an uplink wavelength of the destination wavelength channel And / or downstream wavelength.
结合第一方面或第一方面第二种可能的实现方式， 在第三种可能的实现 方式中， 所述波长切换命令携带波长切换类型信息， 所述波长切换类型信息 用于指示切换上行波长和 /或下行波长。  With reference to the first aspect or the second possible implementation manner of the first aspect, in a third possible implementation, the wavelength switching command carries wavelength switching type information, where the wavelength switching type information is used to indicate that the uplink wavelength is switched. / or downstream wavelength.
结合第一方面至第一方面第二种可能的实现方式中任一种可能的实现方 式， 在第四种可能的实现方式中， 所述方法还包括：  With reference to the possible implementation of the first aspect to the second possible implementation of the first aspect, in a fourth possible implementation, the method further includes:
所述 0LT在本地存储器中存储所述下行数据； 所述 OLT在本地存储器中存储所述下行数据之后， 还包括： 当所述 OLT在所述目的波长通道接收到所述 ONU发送的上行数据或波 长切换完成消息时， 所述 OLT释放所述本地存储器中存储的下行数据。 The OLT stores the downlink data in a local storage; After the OLT stores the downlink data in the local storage, the method further includes: when the OLT receives the uplink data or the wavelength switch completion message sent by the ONU in the destination wavelength channel, the OLT releases the local Downstream data stored in the memory.
结合第一方面第三种可能的实现方式， 在第五种可能的实现方式中， 所 述方法还包括：  In conjunction with the third possible implementation of the first aspect, in a fifth possible implementation, the method further includes:
如果所述 OLT在预设的波长切换定时时间后，未在所述目的波长通道接 收到所述 ONU发送的上行数据或波长切换完成消息，所述 OLT在所述 ONU 回落到所述源波长通道后，在所述源波长通道向所述 ONU发送所述本地存储 器中存储的所述下行数据， 或者所述 OLT在所述 ONU重新注册后， 在所述 ONU重新注册的波长通道上重新向所述 ONU发送所述本地存储器中存储的 所述下行数据。  If the OLT does not receive the uplink data or the wavelength switching completion message sent by the ONU after the preset wavelength switching timing, the OLT falls back to the source wavelength channel in the ONU. After the source wavelength channel sends the downlink data stored in the local memory to the ONU, or after the ONU re-registers, the OLT re-registers on the wavelength channel re-registered by the ONU. The ONU transmits the downlink data stored in the local storage.
结合第一方面至第一方面第五种可能的实现方式中任一种可能的实现方 式，在第六种可能的实现方式中，所述 OLT向 ONU发送波长切换命令之后， 还包括：  With reference to the first aspect to the possible implementation of the fifth possible implementation manner of the first aspect, in a sixth possible implementation manner, after the OLT sends the wavelength switching command to the ONU, the method further includes:
所述 OLT从所述 t0时刻起经过所述时间 T的时刻， 开始通过所述目的 波长通道向所述 ONU发送上行时隙授权。  The OLT starts to send an uplink time slot grant to the ONU through the destination wavelength channel from the time T0 at the time t0.
第二方面提供一种波长切换方法， 包括：  The second aspect provides a wavelength switching method, including:
ONU向 OLT发送波长切换时间消息， 所述波长切换时间消息携带时间 T, 所述时间 T为所述 ONU从源波长通道切换到目的波长通道所需时间， 所 述 T用于指示所述 OLT的等待时间， 所述等待时间是指从所述 ONU开始波 长切换到所述 OLT开始下发下行数据之间的等待时间；  The ONU sends a wavelength switching time message to the OLT, where the wavelength switching time message carries a time T, where the time T is the time required for the ONU to switch from the source wavelength channel to the destination wavelength channel, and the T is used to indicate the OLT. Waiting time, the waiting time is the waiting time between the wavelength switching from the ONU and the downlink data sent by the OLT.
所述 ONU接收所述 OLT发送的所述波长切换命令， 所述波长切换命令 用于指示所述 ONU从源波长通道切换到目的波长通道，其中，所述波长切换 命令携带开始时刻 t0， 所述 t0用于指示所述 ONU在 t0时刻开始从所述源波 长通道切换到所述目的波长通道；  The ONU receives the wavelength switching command sent by the OLT, where the wavelength switching command is used to instruct the ONU to switch from a source wavelength channel to a destination wavelength channel, where the wavelength switching command carries a starting time t0, T0 is used to indicate that the ONU starts to switch from the source wavelength channel to the destination wavelength channel at time t0;
所述 ONU在所述 t0时刻开始从所述源波长通道切换到所述目的波长通 道；  The ONU starts to switch from the source wavelength channel to the destination wavelength channel at the time t0;
所述 ONU在切换到所述目的波长通道后，通过所述目的波长通道接收所 述 OLT发送的下行数据。  After switching to the destination wavelength channel, the ONU receives downlink data sent by the OLT through the destination wavelength channel.
结合第二方面， 在第一种可能的实现方式中， 所述波长切换命令携带所 述目的波长通道的标识； 或携带所述目的波长通道的上行波长和 /或下行波 长。 With reference to the second aspect, in a first possible implementation, the wavelength switching command carries Describe the identifier of the destination wavelength channel; or carry the upstream wavelength and/or the downstream wavelength of the destination wavelength channel.
结合第二方面或第二方面的第一种可能的实现方式， 在第二种可能的实 现方式中， 所述波长切换命令还携带波长切换类型信息， 所述波长切换类型 信息包括切换上行波长和 /或下行波长的指示信息。  With reference to the second aspect or the first possible implementation manner of the second aspect, in a second possible implementation manner, the wavelength switching command further carries wavelength switching type information, where the wavelength switching type information includes switching an uplink wavelength and / or indication of the downstream wavelength.
结合第二方面至第二方面第二种可能的实现方式中任一种可能的实现方 式， 在第三种可能的实现方式中， 所述 ONU在所述 t0时刻， 从所述源波长 通道切换到所述目的波长通道之后， 还包括：  With reference to the second aspect, the second possible implementation manner of the second possible implementation manner, in a third possible implementation manner, the ONU is switched from the source wavelength channel at the time t0 After the destination wavelength channel, the method further includes:
所述 ONU从所述 t0时刻起， 经过时间 T, 通过所述目的波长通道接收 所述 OLT发送的上行时隙授权。  The ONU receives the uplink time slot grant sent by the OLT through the destination wavelength channel from the time t0 and the time T.
第三方面提供一种用于波长切换的装置， 包括：  A third aspect provides an apparatus for wavelength switching, comprising:
处理单元，用于生成波长切换命令，并指示向 ONU发送所述波长切换命 令， 所述波长切换命令用于指示所述 ONU从源波长通道切换到目的波长通 道， 其中， 所述波长切换命令携带开始时刻 t0， 所述 t0用于指示所述 ONU 在 t0时刻开始从所述源波长通道切换到所述目的波长通道； 还用于指示在从 所述 t0时刻起经过时间 T的时刻， 开始通过所述目的波长通道向所述 ONU 发送下行数据。  a processing unit, configured to generate a wavelength switching command, and instruct to send the wavelength switching command to the ONU, where the wavelength switching command is used to instruct the ONU to switch from the source wavelength channel to the destination wavelength channel, where the wavelength switching command carries Starting at time t0, the t0 is used to indicate that the ONU starts to switch from the source wavelength channel to the destination wavelength channel at time t0; and is further configured to indicate that the time elapses from the time t0, start to pass The destination wavelength channel sends downlink data to the ONU.
在第三方面第一种可能的实现方式中， 所述用于波长切换的装置还包括 发送单元，发送单元，用于根据处理单元的指示向所述 ONU发送波长切换命 令； 从所述 t0时刻起， 经过时间 T, 通过所述目的波长通道向所述 ONU发 送下行数据， 其中， 所述时间 T为所述 ONU从所述源波长通道切换到所述 目的波长通道所需时间。  In a first possible implementation manner of the third aspect, the apparatus for wavelength switching further includes: a sending unit, configured to send a wavelength switching command to the ONU according to an indication of the processing unit; The time T is sent to the ONU through the destination wavelength channel, where the time T is the time required for the ONU to switch from the source wavelength channel to the destination wavelength channel.
在第三方面第一种可能的实现方式中， 所述用于波长切换的装置还包括 接收单元， 用于获取所述 ONU上报的所述时间 T。  In a first possible implementation manner of the third aspect, the device for wavelength switching further includes a receiving unit, configured to acquire the time T reported by the ONU.
结合第三方面或第三方面第一种可能的实现方式， 在第二种可能的实现 方式中， 所述波长切换命令携带所述目的波长通道的标识；  With reference to the third aspect, or the first possible implementation manner of the third aspect, in a second possible implementation manner, the wavelength switching command carries an identifier of the destination wavelength channel;
或携带所述目的波长通道的上行波长和 /或下行波长。  Or carrying the upstream wavelength and/or the downstream wavelength of the destination wavelength channel.
结合第三方面或第三方面第二种可能的实现方式， 在第三种可能的实现 方式中， 所述波长切换命令还携带波长切换类型信息， 所述波长切换类型信 息用于指示切换上行波长和 /或下行波长。 结合第三方面至第三方面第二种可能的实现方式中任一种可能的实现方 式， 在第三种可能的实现方式中， 所述用于波长切换的装置还包括： 存储单 元， 用于在本地存储器中存储所述下行数据。 With the third aspect or the second possible implementation manner of the third aspect, in a third possible implementation manner, the wavelength switching command further carries wavelength switching type information, where the wavelength switching type information is used to indicate that the uplink wavelength is switched. And / or downstream wavelength. With reference to any one of the possible implementation manners of the third aspect to the third possible implementation manner, in a third possible implementation, the apparatus for wavelength switching further includes: a storage unit, configured to: The downlink data is stored in a local memory.
结合第三方面第三种可能的实现方式， 在第四种可能的实现方式中， 所 述用于波长切换的装置还包括：  In conjunction with the third possible implementation of the third aspect, in a fourth possible implementation, the apparatus for wavelength switching further includes:
处理单元， 用于当 OLT在所述目的波长通道接收到所述 ONU发送的上 行数据或波长切换完成消息时， 释放所述本地存储器中存储的下行数据。  The processing unit is configured to release the downlink data stored in the local storage when the OLT receives the uplink data or the wavelength switch completion message sent by the ONU in the destination wavelength channel.
结合第三方面第三种可能的实现方式， 在第五种可能的实现方式中， 所 述发送单元，还用于当所述 OLT在预设的波长切换定时时间后未在所述目的 波长通道接收到所述 ONU发送的上行数据或波长切换完成消息时， 在所述 ONU回落到所述源波长通道后， 在所述源波长通道向所述 ONU发送所述本 地存储器中存储的所述下行数据，或者在所述 ONU重新注册后，在所述 ONU 重新注册的波长通道上重新向所述 ONU发送所述本地存储器中存储的所述 下行数据。  With reference to the third possible implementation manner of the third aspect, in a fifth possible implementation, the sending unit is further configured to: when the OLT is not in the destination wavelength channel after a preset wavelength switching timing time Receiving the uplink data or the wavelength switch completion message sent by the ONU, after the ONU falls back to the source wavelength channel, sending the downlink stored in the local memory to the ONU in the source wavelength channel. Data, or after the ONU re-registers, retransmits the downlink data stored in the local memory to the ONU on the wavelength channel re-registered by the ONU.
结合第三方面至第三方面第五种可能的实现方式中任一种可能的实现方 式， 在第六种可能的实现方式中， 所述发送单元， 还用于从所述 to时刻起， 经过所述时间 T, 通过所述目的波长通道向所述 ONU发送上行时隙授权。  With reference to any one of the third aspect to the fifth possible implementation manner of the third aspect, in a sixth possible implementation, the sending unit is further configured to: The time T sends an uplink time slot grant to the ONU through the destination wavelength channel.
第四方面提供一种用于波长切换的装置， 包括：  A fourth aspect provides an apparatus for wavelength switching, including:
发送单元， 用于向 OLT发送波长切换时间消息， 所述波长切换时间消息 携带时间 T,所述时间 T为 ONU从源波长通道切换到目的波长通道所需时间， 所述 T用于指示所述 OLT的等待时间， 所述等待时间是指从所述 ONU开始 波长切换到所述 OLT开始下发下行数据之间的等待时间；  a sending unit, configured to send a wavelength switching time message to the OLT, where the wavelength switching time message carries a time T, where the time T is a time required for the ONU to switch from the source wavelength channel to the destination wavelength channel, where the T is used to indicate the The waiting time of the OLT, the waiting time is the waiting time between the wavelength switching from the ONU and the downlink data sent by the OLT.
接收单元， 用于接收光线路终端 OLT发送的波长切换命令， 所述波长切 换命令用于指示所述 ONU从源波长通道切换到目的波长通道，其中，所述波 长切换命令携带开始时刻 t0， 用于指示所述 ONU在 t0时刻开始从所述源波 长通道切换到所述目的波长通道；  a receiving unit, configured to receive a wavelength switching command sent by the optical line terminal OLT, where the wavelength switching command is used to instruct the ONU to switch from a source wavelength channel to a destination wavelength channel, where the wavelength switching command carries a starting time t0, Instructing the ONU to start switching from the source wavelength channel to the destination wavelength channel at time t0;
处理单元， 用于在所述 to时刻， 从所述源波长通道切换到所述目的波长 通道；  a processing unit, configured to switch from the source wavelength channel to the destination wavelength channel at the time of to;
所述接收单元， 还用于在切换到所述目的波长通道后， 通过所述目的波 长通道接收所述 OLT发送的下行数据。 在第四方面第一种可能的实现方式， 所述波长切换命令携带所述目的波 长通道的标识； The receiving unit is further configured to: after switching to the destination wavelength channel, receive downlink data sent by the OLT through the destination wavelength channel. In a first possible implementation manner of the fourth aspect, the wavelength switching command carries an identifier of the destination wavelength channel;
或携带所述目的波长通道的上行波长和 /或下行波长。  Or carrying the upstream wavelength and/or the downstream wavelength of the destination wavelength channel.
在第四方面第二种可能的实现方式， 所述波长切换命令还携带波长切换 类型信息， 所述波长切换类型信息包括切换上行波长和 /或下行波长的指示信 息。  In a second possible implementation manner of the fourth aspect, the wavelength switching command further carries wavelength switching type information, where the wavelength switching type information includes indication information for switching an uplink wavelength and/or a downlink wavelength.
第五方面提供一种无源光网络***， 包括 OLT和 ONU, 所述 OLT通过 ODN连接至少一个所述 ONU, 所述 OLT包括如第三方面以及第三方面的任 意一种可能的实现方式所述的 OLT, 所述 ONU包括如第四方面以及第四方 面的任意一种可能的实现方式所述的 ONU。  The fifth aspect provides a passive optical network system, including an OLT and an ONU, where the OLT connects at least one of the ONUs by using an ODN, where the OLT includes any possible implementation manner of the third aspect and the third aspect. The OLT, the ONU includes the ONU as described in the fourth aspect and any one of the possible implementations of the fourth aspect.
本发明实施例， OLT在向 ONU发送的波长切换命令中携带开始时刻 t0， 并且 OLT从 t0时刻起间隔时间 T, 就直接向 ONU发送下行数据， 无需等待 ONU的确认完成波长切换的消息， 能在 ONU完成波长切换后第一时间恢复 通信， 降低了波长切换时业务的中断时间。 附图说明  In the embodiment of the present invention, the OLT carries the start time t0 in the wavelength switching command sent to the ONU, and the OLT sends the downlink data directly to the ONU from the time t0, and does not need to wait for the ONU to confirm the completion of the wavelength switching message. After the ONU completes the wavelength switching, the communication is resumed at the first time, and the service interruption time during the wavelength switching is reduced. DRAWINGS
为了更清楚地说明本发明实施例或现有技术中的技术方案， 下面将对实 施例或现有技术描述中所需要使用的附图作简单地介绍， 显而易见地， 下面 描述中的附图是本发明的一些实施例， 对于本领域普通技术人员来讲， 在不 付出创造性劳动性的前提下， 还可以根据这些附图获得其他的附图。  In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings to be used in the embodiments or the description of the prior art will be briefly described below. Obviously, the drawings in the following description are Some embodiments of the present invention may also be used to obtain other drawings based on these drawings without departing from the skilled artisan.
图 1为 TWDM-PON***的网络架构示意图；  Figure 1 is a schematic diagram of a network architecture of a TWDM-PON system;
图 2为本发明实施例提供的波长切换方法实施例一的交互流程图； 图 3为本发明实施例提供的波长切换方法实施例二的交互流程图； 图 4为 PLOAM消息格式示意图；  2 is an interaction flowchart of Embodiment 1 of a wavelength switching method according to an embodiment of the present invention; FIG. 3 is an interaction flowchart of Embodiment 2 of a wavelength switching method according to an embodiment of the present invention; FIG. 4 is a schematic diagram of a PLOAM message format;
图 5为本发明实施例提供的用于波长切换的装置的结构示意图； 图 6为本发明实施例提供的用于波长切换的另一装置的结构示意图； 图 7为本发明实施例提供的一种 OLT的结构示意图；  FIG. 5 is a schematic structural diagram of an apparatus for wavelength switching according to an embodiment of the present invention; FIG. 6 is a schematic structural diagram of another apparatus for wavelength switching according to an embodiment of the present invention; Schematic diagram of the structure of the OLT;
图 8为本发明实施例提供的一种 ONU的结构示意图。 具体实施方式 为使本发明实施例的目的、 技术方案和优点更加清楚， 下面将结合本发 明实施例中的附图， 对本发明实施例中的技术方案进行清楚、 完整地描述， 显然， 所描述的实施例是本发明一部分实施例， 而不是全部的实施例。 基于 本发明中的实施例， 本领域普通技术人员在没有作出创造性劳动前提下所获 得的所有其他实施例， 都属于本发明保护的范围。 FIG. 8 is a schematic structural diagram of an ONU according to an embodiment of the present invention. detailed description The technical solutions in the embodiments of the present invention are clearly and completely described in the following with reference to the accompanying drawings in the embodiments of the present invention. It is a partial embodiment of the invention, and not all of the embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative efforts are within the scope of the present invention.
图 1为 TWDM-PON***的网络架构示意图， 如图 1所示， TWDM-PON *** 100包括一个 OLT110，多个 ONU120和光分配网络（Optical Distribution Network, ODN) 130， 其中 OLTl lO通过 ODN130以点到多点的方式连接到 多个 ONU120。 在 TWDM-PON*** 100中还可以包括一个以上的 OLT。 其 中多个 ONU120共享 ODN130 的光传输介质。 ODN130可以包括主干光纤 131、 光功率分路模块 132和多个分支光纤 133。 其中光功率分路模块 132可 以设置在远端节点 （Remote Node, N) ， 其一方面通过主干光纤 131连接 到 OLT110 , 另一方面通过多个分支光纤 133分别连接至多个 ONU120。 在 TWDM-PON*** 100中， OLT110和多个 ONU120之间的通信链路可以包括 多个波长通道， 多个波长通道通过 WDM方式共享 ODN130的光传输介质。 每个 ONU120可以工作在 TWDM-PON*** 100的其中一个波长通道， 且每 个波长通道可以承载一个或多个 ONU120的业务。 并且， 工作在同一个波长 通道的 ONU120 可以通过 TDM 方式共享该波长通道。 在图 1 中， 以 TWDM-PON*** 100具有四个波长通道为例进行介绍， 应当理解， 在实际 应用时， TWDM-PON*** 100的波长通道的数量还可以根据网络需要而定。  1 is a schematic diagram of a network architecture of a TWDM-PON system. As shown in FIG. 1, the TWDM-PON system 100 includes an OLT 110, a plurality of ONUs 120, and an Optical Distribution Network (ODN) 130, wherein the OLT 110 passes the ODN 130 to point to A multi-point connection to multiple ONUs 120. More than one OLT may also be included in the TWDM-PON system 100. A plurality of ONUs 120 share an optical transmission medium of the ODN130. The ODN 130 may include a backbone fiber 131, an optical power split module 132, and a plurality of branch fibers 133. The optical power splitting module 132 can be disposed at a remote node (N), which is connected to the OLT 110 through the trunk fiber 131 on the one hand, and to the plurality of ONUs 120 through the plurality of branch fibers 133 on the other hand. In the TWDM-PON system 100, the communication link between the OLT 110 and the plurality of ONUs 120 may include a plurality of wavelength channels, and the plurality of wavelength channels share the optical transmission medium of the ODN 130 by WDM. Each ONU 120 can operate in one of the wavelength channels of the TWDM-PON system 100, and each wavelength channel can carry one or more services of the ONU 120. Also, the ONU120 operating in the same wavelength channel can share the wavelength channel by TDM. In FIG. 1, the TWDM-PON system 100 has four wavelength channels as an example. It should be understood that, in practical applications, the number of wavelength channels of the TWDM-PON system 100 may also be determined according to network requirements.
为便于描述， 在图 1中将 TWDM-PON*** 100的四个波长通道分别命 名为波长通道 1、 波长通道 2、 波长通道 3和波长通道 4， 其中每个波长通道 分别采用一对上下行波长， 比如， 波长通道 1 的上行波长和下行波长可以分 别为 λιιΐ和 λ(11， 波长通道 2的上行波长和下行波长可以分别为 λιι2和 λ(12， 波长通道 3的上行波长和下行波长可以分别为 λιι3和 λ(13， 波长通道 4的上 行波长和下行波长可以分别为 λιι4和 λ(14。 每个波长通道可以分别具有对应 的波长通道标识 (：比如， 上述四个波长通道的通道号可以分别为 1、 2、 3、 4), 即波长通道标识与其标识的波长通道的上下行波长具有匹配关系， OLT110 和 ONU120可以根据波长通道标识获悉波长通道的上行波长和下行波长。  For convenience of description, in FIG. 1, the four wavelength channels of the TWDM-PON system 100 are respectively named as wavelength channel 1, wavelength channel 2, wavelength channel 3, and wavelength channel 4, wherein each wavelength channel adopts a pair of uplink and downlink wavelengths respectively. For example, the upstream wavelength and the downstream wavelength of the wavelength channel 1 may be λιιΐ and λ, respectively. (11, the upstream wavelength and the downstream wavelength of the wavelength channel 2 may be λιι2 and λ, respectively. 12, the upstream wavelength and the downstream wavelength of the wavelength channel 3 may be respectively For λιι3 and λ (13, the upstream and downstream wavelengths of the wavelength channel 4 can be λιι 4 and λ, respectively (14. Each wavelength channel can have a corresponding wavelength channel identifier (for example, the channel number of the above four wavelength channels can be 1, 2, 3, 4), that is, the wavelength channel identifier has a matching relationship with the upstream and downstream wavelengths of the wavelength channel to which it is identified, and the OLT 110 and the ONU 120 can learn the upstream wavelength and the downstream wavelength of the wavelength channel according to the wavelength channel identifier.
OLT110可以包括光耦合器 111、 第一波分复用器 112、 第二波分复用器 113、 多个下行光发射器 Txl~Tx4、 多个上行光接收器 Rxl~Rx4和处理模块The OLT 110 may include an optical coupler 111, a first wavelength division multiplexer 112, and a second wavelength division multiplexer. 113, multiple downlink optical transmitters Txl~Tx4, multiple upstream optical receivers Rxl~Rx4 and processing module
114。 其中， 多个下行光发射器 Txl~Tx4通过第一波分复用器 112连接到光 耦合器 111， 多个上行光接收器 Rxl~Rx4通过第二波分复用器 113连接到光 耦合器 111， 耦合器 111进一歩连接到 ODN130的主干光纤 131。 114. The plurality of downstream optical transmitters Tx1 to Tx4 are connected to the optical coupler 111 through the first wavelength division multiplexer 112, and the plurality of upstream optical receivers Rx1 to Rx4 are connected to the optical coupler through the second wavelength division multiplexer 113. 111, the coupler 111 is further connected to the trunk fiber 131 of the ODN 130.
多个下行光发射器 Txl~Tx4的发射波长各不相同， 其中， 每一个下行光 发射器 Txl~Tx4可以分别对应 TWDM-PON*** 100的其中一个波长通道， 比如多个下行光发射器 Txl~Tx4的发射波长可以分别 λ(11~λ(14。 下行光发射 器 Txl~Tx4可以分别利用其发射波长 λ(11~λ(14将下行数据发射到对应的波长 通道， 以便被工作在对应波长通道的 ONU120所接收。 相对应地， 多个上行 光接收器 Rxl~Rx4 的接收波长可以各不相同， 其中每一个上行光接收器 xl~Rx4 同样分别对应 TWDM-PON*** 100 的其中一个波长通道， 比如, 多个上行光接收器 Rxl~Rx4 的接收波长可以分别 λιι1~λιι4。 上行光接收器 Rxl~Rx4 可以分别利用其接收波长 λιι1~λιι4 接收工作在对应波长通道的 ONU120发送的上行数据。  The emission wavelengths of the plurality of downlink optical transmitters Tx1 to Tx4 are different. Each of the downstream optical transmitters Tx1 to Tx4 can respectively correspond to one of the wavelength channels of the TWDM-PON system 100, for example, multiple downlink optical transmitters Txl~. The emission wavelength of Tx4 can be λ(11~λ(14.) The downstream optical transmitters Txl~Tx4 can respectively use their emission wavelength λ (11~λ (14 will transmit downlink data to the corresponding wavelength channel, so as to be operated at the corresponding wavelength). Correspondingly, the receiving wavelengths of the plurality of uplink optical receivers Rx1 to Rx4 may be different, and each of the upstream optical receivers x1 to Rx4 also respectively correspond to one of the wavelength channels of the TWDM-PON system 100. For example, the receiving wavelengths of the plurality of upstream optical receivers Rxl~Rx4 may be respectively λιι1~λιι4. The upstream optical receivers Rxl~Rx4 may receive the uplink data transmitted by the ONUs 120 operating in the corresponding wavelength channel by using the receiving wavelengths λιι1~λι4, respectively.
第一波分复用器 112用于将多个下行光发射器 Txl~Tx4发射的波长分别 为 λ(11~λ(14 的下行数据进行波分复用处理， 并通过光耦合器 111 发送到 ODN130的主干光纤 131， 以通过 ODN130将下行数据提供给 ONU120。 并 且， 光耦合器 111还可以用于将来自多个 ONU120且波长分别为 λιι1~λιι4的 上行数据提供给第二波分复用器 113， 第二波分复用器 113可以将波长分别 为 λιι1~λιι4的上行数据解复用到上行光接收器 Rxl~Rx4进行数据接收。  The first wavelength division multiplexer 112 is configured to respectively transmit the wavelengths of the plurality of downlink optical transmitters Tx1 to Tx4 to λ (11~λ (14 downlink data is subjected to wavelength division multiplexing processing, and is sent to the optical coupler 111 through the optical coupler 111). The backbone fiber 131 of the ODN 130 provides downlink data to the ONU 120 through the ODN 130. The optocoupler 111 can also be used to provide uplink data from the plurality of ONUs 120 and having wavelengths of λιι1 to λι4 to the second wavelength division multiplexer. 113. The second wavelength division multiplexer 113 may demultiplex the uplink data having the wavelengths λιι to λι4 to the upstream optical receivers Rx1 to Rx4 for data reception.
处理模块 114可以为媒介接入控制（Media Access Control, MAC)模块， 其一方面可以通过波长协商为多个 ONU120指定工作波长通道， 并根据某个 ONU120的工作波长通道， 将待发送给 ONU120的下行数据提供给与波长通 道相对应的下行光发射器 Txl~Tx4， 以便下行光发射器 Txl~Tx4将下行数据 发射到对应波长通道， 另一方面， 处理模块 114还可以对各个波长通道进行 上行发送的动态带宽分配 （Dynamic Bandwidth Allocation, DBA) ， 给通过 TDM方式复用到同一个波长通道的 ONU120 分配上行发送时隙， 以授权 ONU120在指定的时隙通过其对应的波长通道发送上行数据。  The processing module 114 may be a Media Access Control (MAC) module, which may specify a working wavelength channel for the plurality of ONUs 120 by wavelength negotiation, and send the signal to be sent to the ONU 120 according to the working wavelength channel of the ONU 120. The downlink data is provided to the downlink optical transmitters Tx1 to Tx4 corresponding to the wavelength channels, so that the downlink optical transmitters Tx1 to Tx4 transmit the downlink data to the corresponding wavelength channels. On the other hand, the processing module 114 can also uplink the respective wavelength channels. The Dynamic Bandwidth Allocation (DBA) is configured to allocate an uplink transmission slot to the ONU 120 multiplexed to the same wavelength channel by the TDM mode, to authorize the ONU 120 to transmit uplink data through the corresponding wavelength channel in the designated time slot.
每个 ONU120的上行发射波长和下行接收波长是可调的， ONU120可以 根据 OLT110指定的波长通道将其自身的上行发射波长和下行接收波长分别 调整到该波长通道的上行波长和下行波长， 从而实现通过该波长通道进行上 下行数据的发送和接收。 比如， 如果 OLT110在波长协商过程中指示某一个 ONU120工作到波长通道 1， ONU120可以将其自身的上行发射波长和下行接 收波长分别调整到第一上行波长 λιιΐ和第一下行波长 λ(11 ;如果 OLT110指示 ONU120工作到波长通道 3， ONU120可以将其自身的上行发射波长和下行接 收波长分别调整到第三上行波长 λιι3和第一下行波长 λ(13。 The uplink transmit wavelength and the downlink receive wavelength of each ONU 120 are adjustable, and the ONU 120 can respectively set its own uplink transmit wavelength and downlink receive wavelength according to the wavelength channel specified by the OLT 110. The uplink wavelength and the downlink wavelength of the wavelength channel are adjusted, so that uplink and downlink data transmission and reception are performed through the wavelength channel. For example, if the OLT 110 indicates that an ONU 120 is operating to the wavelength channel 1 during the wavelength negotiation process, the ONU 120 can adjust its own uplink transmit wavelength and downlink receive wavelength to the first uplink wavelength λιιΐ and the first downlink wavelength λ, respectively (11 ; If the OLT 110 instructs the ONU 120 to operate to the wavelength channel 3, the ONU 120 can adjust its own uplink transmission wavelength and downlink reception wavelength to the third uplink wavelength λιι3 and the first downlink wavelength λ, respectively.
ONU120可以包括光耦合器 121、 下行光接收器 122、 上行光发射器 123 和处理模块 124。 其中， 下行光接收器 122和上行光发射器 123通过光耦合 器 121连接到 ONU120对应的分支光纤 133。 光耦合器 121可以一方面将上 行光发射器 123 发送的上行数据提供到 ODN130 的分支光纤 133， 以通过 ODN130发送给 OLT110; 另一方面， 光耦合器 121还可以将 OLT110通过 ODN130发送的下行数据提供给下行光接收器 122进行数据接收。  The ONU 120 can include an optocoupler 121, a downstream optical receiver 122, an upstream optical transmitter 123, and a processing module 124. The downstream optical receiver 122 and the upstream optical transmitter 123 are connected to the branch optical fiber 133 corresponding to the ONU 120 through the optical coupler 121. The optical coupler 121 can provide the uplink data sent by the upstream optical transmitter 123 to the branch fiber 133 of the ODN 130 to be sent to the OLT 110 through the ODN 130. On the other hand, the optical coupler 121 can also send the downlink data sent by the OLT 110 through the ODN 130. The downlink optical receiver 122 is provided for data reception.
处理模块 124可以是 MAC模块， 其可以与 OLT110进行波长协商， 并 根据 OLT110指定的波长通道， 调整下行光接收器 122的接收波长和上行光 发射器 123的发射波长 (即调整 ONU120的下行接收波长和上行发射波长：)， 以使得 ONU120工作在 OLT110指定的波长通道； 另外， 处理模块 124还可 以根据 OLT110的动态带宽分配结果， 控制上行光发射器 123在指定的时隙 发送上行数据。  The processing module 124 can be a MAC module, which can perform wavelength negotiation with the OLT 110, and adjust the receiving wavelength of the downstream optical receiver 122 and the transmitting wavelength of the upstream optical transmitter 123 according to the wavelength channel specified by the OLT 110 (ie, adjusting the downlink receiving wavelength of the ONU 120). And the uplink transmit wavelength:), so that the ONU 120 operates in the wavelength channel specified by the OLT 110; in addition, the processing module 124 can also control the uplink optical transmitter 123 to send uplink data in the designated time slot according to the dynamic bandwidth allocation result of the OLT 110.
当 TWDM-PON*** 100运行时， 如果上线的 ONU120数量较多， 一种 较为理想情况是分别有部分 ONU120工作在波长通道 1、 部分工作在波长通 道 2、 部分工作在波长通道 3、 部分工作在波长通道 4， 并且各个波长通道的 ONU120 的数量基本相等。 不过， 在实际工作中， 由于用户动态上下线等原 因， 每个波长通道的 ONU120的数量可能是不同的， 比如有可能出现某一个 波长通道的 ONU120的数量较多， 且另一个或多个波长通道的 ONU120的数 量较少甚至出现没有 ONU120使用的波长通道， 即出现波长通道的负载不均 衡。 在这种情况下， 较多 ONU120使用的波长通道的负载较重， 由于工作在 同一个波长通道的 ONU120采用 TDM方式进行业务复用， 当某一个波长通 道的负载过重时可能会出现带宽不足而影响所述 ONU120的正常业务。 本发 明实施例提供波长切换的方法可以解决 OLT波长通道负载不均衡的问题，详 见以下具体实施例。 实施例一 When the TWDM-PON system 100 is running, if the number of ONUs 120 on the line is large, an ideal situation is that some ONUs 120 work in the wavelength channel 1, part of the operation in the wavelength channel 2, part of the operation in the wavelength channel 3, and part of the operation. Wavelength channel 4, and the number of ONUs 120 of each wavelength channel is substantially equal. However, in actual work, the number of ONUs 120 per wavelength channel may be different due to the user moving up and down, etc., for example, there may be a large number of ONUs 120 of one wavelength channel, and another wavelength or wavelengths. The number of ONUs 120 of the channel is small and there is no wavelength channel that is not used by the ONU 120, that is, the load of the wavelength channel is unbalanced. In this case, the load of the wavelength channel used by the more ONUs is heavy. The ONUs 120 operating in the same wavelength channel use TDM to perform service multiplexing. When the load of a certain wavelength channel is too heavy, bandwidth may be insufficient. The normal service of the ONU 120 is affected. The method for wavelength switching in the embodiment of the present invention can solve the problem that the OLT wavelength channel load is unbalanced. For details, refer to the following specific embodiments. Embodiment 1
图 2为本发明实施例提供的波长切换方法实施例一的交互流程图， 如图 2所示， 本实施例的方法包括：  FIG. 2 is an interaction flowchart of Embodiment 1 of a wavelength switching method according to an embodiment of the present invention. As shown in FIG. 2, the method in this embodiment includes:
歩骤 S201， OLT向 ONU发送波长切换命令。  Step S201: The OLT sends a wavelength switching command to the ONU.
具体地，OLT向 ONU发送的波长切换命令用于指示 ONU进行波长切换， 并且，波长切换命令用于指示 ONU从源波长通道切换到目的波长通道，其中， 波长切换命令携带开始时刻 t0， 用于指示 ONU在 t0时刻开始从源波长通道 切换到目的波长通道。  Specifically, the wavelength switching command sent by the OLT to the ONU is used to instruct the ONU to perform wavelength switching, and the wavelength switching command is used to instruct the ONU to switch from the source wavelength channel to the destination wavelength channel, where the wavelength switching command carries the starting time t0, which is used for Instructs the ONU to switch from the source wavelength channel to the destination wavelength channel at time t0.
需要说明的是， 这里的源波长通道和目的波长通道仅仅表明是 TWDM-PON***中可以工作的任意两个通道，源波长通道表示 ONU正在工 作的波长通道， 目的波长通道表示 OLT指示 ONU切换到的波长通道。此外， 实际工作中， 在波长切换过程中， 上下行的波长对并不需要唯一绑定配对， 即对于源波长通道和目的波长通道的上行波长可以是相同的波长， 同理源波 长通道和目的波长通道的下行波长也可以相同。 也就是说， 在本实施例中， OLT可以仅指示 ONU进行上行波长的切换， 或者仅进行下行波长的切换， 或者同时进行上行波长和下行波长的切换。  It should be noted that the source wavelength channel and the destination wavelength channel herein only indicate any two channels that can work in the TWDM-PON system, the source wavelength channel indicates the wavelength channel in which the ONU is working, and the destination wavelength channel indicates that the OLT indicates that the ONU switches to Wavelength channel. In addition, in actual operation, in the wavelength switching process, the upstream and downstream wavelength pairs do not need to be uniquely paired, that is, the upstream wavelengths of the source wavelength channel and the destination wavelength channel may be the same wavelength, and the same source wavelength channel and purpose The downstream wavelength of the wavelength channel can also be the same. That is to say, in this embodiment, the OLT may only instruct the ONU to perform uplink wavelength switching, or only perform downlink wavelength switching, or simultaneously perform uplink wavelength and downlink wavelength switching.
可选地， OLT获取时间 T, 所述时间 T为 ONU从源波长通道切换到目 的波长通道所需时间。 其中， 每个波长通道包含一个波长对， 该波长对包括 上行波长和下行波长。源波长通道和目的波长通道可以是只有上行波长不同， 或者只有下行波长不同， 也可以是上下行波长都不同。 当只切上行波长， 那 么时间 T可以是相应的上行波长的切换时间； 当只切下行波长， 那么时间 T 可以是相应的下行波长的切换时间； 当同时切换上下行波长时， 时间 T可以 是指上行波长切换时间和下行波长切换时间中时间较长的一个。  Optionally, the OLT acquires a time T, which is a time required for the ONU to switch from the source wavelength channel to the destination wavelength channel. Each wavelength channel includes a pair of wavelengths including an upstream wavelength and a downstream wavelength. The source wavelength channel and the destination wavelength channel may have different uplink wavelengths, or only the downstream wavelengths may be different, or the uplink and downlink wavelengths may be different. When only the upstream wavelength is cut, the time T may be the switching time of the corresponding uplink wavelength; when only the downlink wavelength is cut, the time T may be the switching time of the corresponding downlink wavelength; when the uplink and downlink wavelengths are simultaneously switched, the time T may be Refers to the longer one of the upstream wavelength switching time and the downstream wavelength switching time.
其中， 上行波长的切换是指， 通过相应的控制部件去调谐激光器的发射 波长， 下行波长的切换可以是指通过控制部件去控制可调谐滤波器的滤波带 宽或其他滤波参数。 上下行波长的切换均为现有技术， 在此不做详述。 当然， 不同的上行波长之间的切换时间可能是不同的， 不同的下行波长之间的切换 时间也可能是不同的。 因此， 相应的时间 T跟源波长通道和目的波长通道是 相对应的， 每种源波长通道和目的波长通道的组合对应一个相应的时间 T。 当然， 当 ONU需要上报相应的 Τ时， 其也可以上报源波长通道和目的波长 通道的组合以及相对应的时间 τ。 The switching of the upstream wavelength means that the emission wavelength of the laser is tuned by the corresponding control component, and the switching of the downstream wavelength may refer to controlling the filtering bandwidth or other filtering parameters of the tunable filter through the control component. The switching of the uplink and downlink wavelengths is a prior art and will not be described in detail herein. Of course, the switching time between different upstream wavelengths may be different, and the switching time between different downstream wavelengths may also be different. Therefore, the corresponding time T corresponds to the source wavelength channel and the destination wavelength channel, and the combination of each of the source wavelength channel and the destination wavelength channel corresponds to a corresponding time T. Of course, when the ONU needs to report the corresponding chirp, it can also report the source wavelength channel and the destination wavelength. The combination of channels and the corresponding time τ.
OLT获取 ONU进行波长切换所需要的时间 T的方法有多种， 例如 ONU 在注册时或者注册后向 OLT上报该 ONU从源波长通道 （不妨设其上下行波 长分别为 λιιΐ , λάΐ )切换到目的波长通道（不妨设其上下行波长分别为 λιι2， λά2 ) 过程所需要的时间 Τ。  There are various methods for the OLT to obtain the time T required for the ONU to perform wavelength switching. For example, the ONU reports to the OLT during registration or registration, and the ONU switches from the source wavelength channel (may set its uplink and downlink wavelengths to λιιΐ, λάΐ respectively) to the destination. The time required for the wavelength channel (may be set to λιι2, λά2 for the upstream and downstream wavelengths respectively).
具体可以是 OLT接收到 ONU发送的波长切换信息， 该波长切换信息携 带时间 T， OLT从波长切换信息中获取该时间 Τ, 这种方法适用于 ONU为新 注册的 ONU,或者 OLT中没有保存 ONU进行波长切换所需要的时间 Τ的情 况。  Specifically, the OLT receives the wavelength switching information sent by the ONU, where the wavelength switching information carries the time T, and the OLT obtains the time 从 from the wavelength switching information. The method is applicable to the ONU being the newly registered ONU, or the ONU is not saved in the OLT. The time required for wavelength switching.
OLT还可以从本地存储器中读取存储的该 ONU进行波长切换所需的时 间 Τ， 存储器中存储的时间 Τ可以是 ONU之前向 OLT发送的， 或者可以是 OLT根据 ONU发送的其他信息计算得出的， 或者可以是通过命令行或网管 ***人工输入的。  The OLT can also read the time required for the ONU to perform wavelength switching from the local storage. The time stored in the memory can be sent to the OLT before the ONU, or can be calculated by the OLT according to other information sent by the ONU. Or, it can be manually entered through the command line or the network management system.
可选地， OLT在向 ONU发送波长切换命令之前， 为该 ONU分配一个目 的波长通道。 在实际工作中， 为实现所述 TWDM-PON***各个波长通道之 间的负载均衡 （Load Balance) ， OLT在 ONU的工作过程中可能需要指示 ONU进行波长切换， 比如， 当波长通道 A的负载过大而波长通道 B空闲时， 所述 OLT 可以通过波长切换命令控制原来工作在所述波长通道 A 的部分 ONU通过调整其上行发射波长和 /或下行接收波长的方式切换到所述波长通 道^  Optionally, the OLT allocates a destination wavelength channel to the ONU before sending the wavelength switching command to the ONU. In actual operation, in order to implement load balancing between the wavelength channels of the TWDM-PON system, the OLT may need to instruct the ONU to perform wavelength switching during the operation of the ONU, for example, when the wavelength channel A is loaded. When the wavelength channel B is idle, the OLT can control a part of the ONUs that are working in the wavelength channel A to switch to the wavelength channel by adjusting the uplink transmission wavelength and/or the downlink reception wavelength by using a wavelength switching command.
如果 OLT存在多个空闲波长通道， OLT为 ONU分配一个目的波长通道， 可以将上述多个空闲波长通道中的任意一个波长通道分配给该 ONU; 或者选 择最优的一个波长通道分配给该 ONU; 或者根据某一个算法来挑选某一波长 通道分配给该 ONU, 本发明实施例并不限定如何选择目的波长通道。  If the OLT has multiple idle wavelength channels, the OLT allocates a destination wavelength channel to the ONU, and assigns any one of the plurality of idle wavelength channels to the ONU; or selects an optimal one of the wavelength channels to allocate to the ONU; Or, according to an algorithm, a certain wavelength channel is selected and allocated to the ONU. The embodiment of the present invention does not limit how to select the destination wavelength channel.
可选地，上述波长切换命令可以在 ONU注册过程中发送，还可以在 ONU 注册完成， 上线以后发送。  Optionally, the foregoing wavelength switching command may be sent during the ONU registration process, and may also be registered in the ONU and sent after being sent online.
歩骤 S202， ONU接收波长切换命令， 在 t0时刻， 从源波长通道切换到 目的波长通道。  Step S202: The ONU receives the wavelength switching command, and switches from the source wavelength channel to the destination wavelength channel at time t0.
具体地， 当 ONU接收到 OLT发送的波长切换命令后， 依据该波长切换 命令中的信息， 进行波长切换， 从源波长通道切换到目的波长通道。 可选地， 所述波长切换命令是指示该 ONU切换上行波长和下行波长， ONU需要调整自己的光接收机和光发射机， 以对准目的波长通道的上行波长 和下行波长； 如果所述波长切换命令是指示该 ONU切换上行波长， ONU只 需要调整自己的光发射机， 以对准该上行波长； 同理地， 如果所述波长切换 命令是指示该 ONU切换下行波长， 那么 ONU只需要调整自己的光接收机， 以对准所述下行波长。 Specifically, after receiving the wavelength switching command sent by the OLT, the ONU performs wavelength switching according to the information in the wavelength switching command, and switches from the source wavelength channel to the destination wavelength channel. Optionally, the wavelength switching command is to instruct the ONU to switch the uplink wavelength and the downlink wavelength, and the ONU needs to adjust its own optical receiver and optical transmitter to align the uplink wavelength and the downlink wavelength of the destination wavelength channel; The command is to instruct the ONU to switch the upstream wavelength. The ONU only needs to adjust its own optical transmitter to align the upstream wavelength. Similarly, if the wavelength switching command indicates that the ONU switches the downstream wavelength, the ONU only needs to adjust itself. An optical receiver to align the downstream wavelength.
另外， 在 OLT发送的波长切换命令中携带开始时刻 t0， ONU将从 t0时 刻开始进行波长切换。 该开始时刻 t0是由 OLT配置的， 开始时刻 t0可以是 ONU接收到波长切换命令后的任意时刻。  Further, the wavelength switching command transmitted by the OLT carries the start time t0, and the ONU starts the wavelength switching from the time t0. The start time t0 is configured by the OLT, and the start time t0 may be any time after the ONU receives the wavelength switching command.
歩骤 S203， OLT从 t0时刻起， 经过时间 T, 通过目的波长通道向 ONU 发送下行数据， 其中， 时间 T为 ONU从源波长通道切换到目的波长通道所 需时间。  Step S203: The OLT sends downlink data to the ONU through the destination wavelength channel from the time t0, and the time T is the time required for the ONU to switch from the source wavelength channel to the destination wavelength channel.
可选地， 所述时间 T可以是 ONU上报至 OLT, 也可以是 OLT通过配置 或者外部输入或者计算获取。  Optionally, the time T may be reported by the ONU to the OLT, or may be obtained by the OLT through configuration or external input or calculation.
值得说明的是， 如果 OLT指示 ONU只切换上行波长， OLT仍应从源波 长通道下发下行数据，通过目的波长通道接收上行数据。如果 OLT指示 ONU 只切换下行波长， OLT通过目的波长通道下发下行数据。  It is worth noting that if the OLT instructs the ONU to switch only the upstream wavelength, the OLT should still send downlink data from the source wavelength channel and receive uplink data through the destination wavelength channel. If the OLT instructs the ONU to switch only the downlink wavelength, the OLT sends downlink data through the destination wavelength channel.
S204, 所述 ONU在切换到所述目的波长通道后， 通过目的波长通道接 收 OLT发送的下行数据。  S204. After switching to the destination wavelength channel, the ONU receives downlink data sent by the OLT through the destination wavelength channel.
具体地，为了解决现有波长切换方法的问题，在本实施例中，OTL向 ONU 发送波长切换命令后， 从 t0时刻起， 经过时间 T就直接向 ONU发送下行数 据， 其中， 时间 T为 ONU从源波长通道切换到目的波长通道所需时间。 而 不需要再向 ONU发送是否完成切换的询问消息， 也不需要接收 ONU发送的 已经完成波长切换消息。 由于该时间 T为 ONU从源波长通道切换到目的波 长通道所需的时间， 因此从 t0时刻起， 经过时间 T后 ONU已经切换到了目 的波长通道，此时 OLT在目的波长通道发送的下行数据能够被 ONU接收到。 这样就完成了波长切换过程。  Specifically, in order to solve the problem of the existing wavelength switching method, in the embodiment, after the OTL sends the wavelength switching command to the ONU, the downlink data is directly sent to the ONU after the time T from the time t0, where the time T is the ONU. The time it takes to switch from the source wavelength channel to the destination wavelength channel. There is no need to send an inquiry message to the ONU to complete the handover, and it is not necessary to receive the completed wavelength switching message sent by the ONU. Since the time T is the time required for the ONU to switch from the source wavelength channel to the destination wavelength channel, the ONU has switched to the destination wavelength channel after the time T from the time t0, and the downlink data sent by the OLT in the destination wavelength channel can be Received by the ONU. This completes the wavelength switching process.
本实施例， OLT在向 ONU发送波长切换命令携带开始时刻 t0， 从 t0时 刻起间隔时间 T， OTL向 ONU发送下行数据， 从而节约了 OLT与 ONU之 间进行波长切换确认的时间， 降低了波长切换时业务的中断时间。 实施例二 In this embodiment, the OLT sends the wavelength switching command carrying start time t0 to the ONU, and the interval time T from the time t0, the OTL sends the downlink data to the ONU, thereby saving the time for the wavelength switching confirmation between the OLT and the ONU, and reducing the wavelength. The interruption time of the service when switching. Embodiment 2
下面结合具体的应用场景对本发明进一歩说明。 图 3为本发明实施例提 供的波长切换方法实施例二的交互流程图， 如图 3所示， 本实施例的方法包 括：  The present invention will be further described below in conjunction with specific application scenarios. FIG. 3 is an interaction flowchart of Embodiment 2 of a wavelength switching method according to an embodiment of the present invention. As shown in FIG. 3, the method in this embodiment includes:
歩骤 S301， OLT获取时间 T, 所述时间 T为 ONU从源波长通道切换到 目的波长通道所需时间。  Step S301: The OLT acquires a time T, where the time T is a time required for the ONU to switch from the source wavelength channel to the destination wavelength channel.
具体地， OLT向 ONU发送波长切换命令之前， OLT首先获取需要进行 波长切换的 ONU进行波长切换所需要的时间 T。 该时间 Τ为 ONU从正在工 作的源波长通道切换到需要切换到的目的波长通道所需的时间。  Specifically, before the OLT sends a wavelength switching command to the ONU, the OLT first acquires the time T required for the wavelength switching by the ONU that needs to perform wavelength switching. This time is the time it takes for the ONU to switch from the source wavelength channel in operation to the destination wavelength channel that needs to be switched.
OLT获取 ONU进行波长切换所需要的时间 Τ的方法有多种， 例如 ONU 在注册时或者注册后向 OLT上报该 ONU从源波长通道 （不妨设其上下行波 长分别为 λιιΐ , λάΐ )切换到目的波长通道（不妨设其上下行波长分别为 λιι2， λά2 ) 过程所需要的时间 Τ。  There are various methods for the OLT to obtain the time required for the ONU to perform wavelength switching. For example, the ONU reports to the OLT during registration or registration, and the ONU switches from the source wavelength channel (may set its uplink and downlink wavelengths to λιιΐ, λάΐ respectively) to the destination. The time required for the wavelength channel (may be set to λιι2, λά2 for the upstream and downstream wavelengths respectively).
具体可以是 OLT接收到 ONU发送的波长切换时间消息， 该波长切换时 间消息携带时间 T， OLT从波长切换时间消息中获取该时间 Τ, 所述 Τ用于 指示所述 OLT的等待时间， 所述等待时间是指从所述 ONU开始波长切换到 所述 OLT开始下发下行数据之间的等待时间；这种方法适用于新注册的 ONU 或者 OLT中没有保存 ONU进行波长切换所需要的时间 Τ的情况。  Specifically, the OLT receives the wavelength switching time message sent by the ONU, where the wavelength switching time message carries the time T, and the OLT obtains the time Τ from the wavelength switching time message, where the Τ is used to indicate the waiting time of the OLT, where The waiting time is the waiting time between the wavelength switching of the ONU and the downlink data sent by the OLT. This method is applicable to the time required for the newly registered ONU or the OLT to save the ONU for wavelength switching. Happening.
需要说明的是， 比如， ONU从波长通道 1切换到波长通道 2的时间为 a, 从波长通道 1切换到波长通道 3的时间为 b，b>a，那么 ONU可以分别上报 a、 b， 也可以只上报波长通道切换最长的时间 b。 这里的切换是指从源波长对切 换到目的波长对， 包括上行波长和下行波长。  It should be noted that, for example, the time when the ONU switches from the wavelength channel 1 to the wavelength channel 2 is a, and the time from the wavelength channel 1 to the wavelength channel 3 is b, b>a, then the ONU can report a, b, respectively. It is possible to report only the wavelength channel switching for the longest time b. Switching here refers to switching from the source wavelength pair to the destination wavelength pair, including the upstream wavelength and the downstream wavelength.
OLT还可以从本地存储器中读取存储的该 ONU进行波长切换所需的时 间 T， 存储器中存储的时间 Τ可以是 ONU之前向 OLT发送的， 或者可以是 OLT根据 ONU发送的其他信息计算得出的， 或者可以是通过命令行或网管 ***人工输入的。  The OLT can also read the stored time T of the stored ONU for wavelength switching, and the time Τ stored in the memory can be sent to the OLT before the ONU, or can be calculated by the OLT according to other information sent by the ONU. Or, it can be manually entered through the command line or the network management system.
进一歩地， ONU 可以通过物理层操作管理和维护 （Physical Layer Operations Administration and Maintenance, PLOAM) 消息、 光网络终端管理 和控制接口 （ONT Management and Control Interface, OMCI) 消息、 多点控 制协议 （Multi-Point Control Protocols , MPCP ) 消息或者操作管理和维护 (Operation Administration and Maintenance, OAM) 消息其中的任意一禾中来 承载上述 ONU向 0LT发送的波长切换时间消息。在其他替代实施例中，0NU 也可以通过新定义的消息来承载向 OLT发送的波长切换时间信息。 Further, the ONU can pass the Physical Layer Operations Administration and Maintenance (PLOAM) message, the Optical Network Terminal Management and Control Interface (OMCI) message, and the Multipoint Control Protocol (Multi- Point Control Protocols, MPCP) Message or Operations Management and Maintenance (Operation Administration and Maintenance, OAM) The message carries any of the wavelength switching time messages sent by the ONU to the OLT. In other alternative embodiments, the ONU may also carry the wavelength switching time information sent to the OLT through the newly defined message.
以采用 PLOAM消息来承载波长切换时间消息为例， PLOAM消息的消 息格式如图 4所示， 图 4为 PLOAM消息格式示意图。 PLOAM消息通常包 括光网络单元标识 （ONU ID) 字段、 消息标识 （Message ID) 字段、 序列号 ( Sequence No) 字段、 数据 （Data) 字段和完整性检査 （Integrity Check) 字 段。 在本发明实施例中， 波长切换时间信息可以承载在 PLOAM消息的数据 字段。  Taking the PLOAM message to carry the wavelength switching time message as an example, the message format of the PLOAM message is shown in FIG. 4, and FIG. 4 is a schematic diagram of the PLOAM message format. PLOAM messages typically include an Optical Network Unit Identification (ONU ID) field, a Message ID (Message ID) field, a Sequence Number field, a Data field, and an Integrity Check field. In the embodiment of the present invention, the wavelength switching time information may be carried in a data field of a PLOAM message.
歩骤 S302， OLT确定指示 ONU从源波长通道切换到目的波长通道。 具体地， OLT向 ONU发送波长切换命令之前， 还需要确定是否需要指 示 ONU从源波长通道切换到目的波长通道。 OLT确定指示 ONU从源波长通 道切换到目的波长通道的依据有多种情况， 包括： 若所述源波长通道的负载 超过预设的过载阈值且所述目的波长通道的负载未超过预设的过载阈值， 则 所述 OLT确定指示所述 ONU从所述源波长通道切换到所述目的波长通道； 或者若所述原波长通道的负载低于预设的轻载阈值且所述目的波长通道的负 载未超过预设的过载阈值， 则所述 OLT确定指示所述 ONU从所述源波长通 道切换到所述目的波长通道； 或者若所述源波长通道对应的光收发器件出现 故障或性能低于预设性能阈值， 则所述 OLT确定指示所述 ONU从所述源波 长通道切换到所述目的波长通道。  Step S302, the OLT determines to instruct the ONU to switch from the source wavelength channel to the destination wavelength channel. Specifically, before the OLT sends the wavelength switching command to the ONU, it is also required to determine whether the ONU needs to be switched from the source wavelength channel to the destination wavelength channel. The OLT determines that the ONU switches from the source wavelength channel to the destination wavelength channel according to various situations, including: if the load of the source wavelength channel exceeds a preset overload threshold and the load of the destination wavelength channel does not exceed a preset overload a threshold, the OLT determines to indicate that the ONU is switched from the source wavelength channel to the destination wavelength channel; or if the load of the original wavelength channel is lower than a preset light load threshold and the load of the destination wavelength channel If the preset overload threshold is not exceeded, the OLT determines to indicate that the ONU switches from the source wavelength channel to the destination wavelength channel; or if the optical transceiver device corresponding to the source wavelength channel fails or the performance is lower than the pre- Setting a performance threshold, the OLT determines to instruct the ONU to switch from the source wavelength channel to the destination wavelength channel.
OLT可以实时检测 TWDM-PON***中的各个波长通道的上下行业务负 载情况， 用以判断是否需要进行波长切换。 当检测出 TWDM-PON***出现 波长通道负载不均衡时， 比如， 当波长通道 1下行负载过重， 波长通道 2下 行负载较轻， 而波长通道 3和 4下行负载正常时， OLT可以判断出需要指示 原来工作在波长通道 1的 ONU切换到波长通道 2进行下行业务接收，即此时 OLT可以判断出需要指示此部分 ONU将其下行接收波长从波长通道 1的下 行波长切换到波长通道 2的下行波长。  The OLT can detect the uplink and downlink traffic load of each wavelength channel in the TWDM-PON system in real time to determine whether wavelength switching is required. When the wavelength channel load imbalance of the TWDM-PON system is detected, for example, when the downlink load of the wavelength channel 1 is too heavy, the downlink load of the wavelength channel 2 is light, and when the downlink load of the wavelength channels 3 and 4 is normal, the OLT can determine the need. Indicates that the ONU that is working in the wavelength channel 1 switches to the wavelength channel 2 for downlink service reception. That is, the OLT can determine that the ONU needs to instruct the ONU to switch its downlink receiving wavelength from the downstream wavelength of the wavelength channel 1 to the downstream of the wavelength channel 2. wavelength.
应当理解，上述根据波长通道的负载情况来判断是否需要指示 ONU进行 波长切换只是为了实现负载均衡需求的一种判断依据， 在具体实施方式中， OLT还可以出于节能或者光收发器件更换的需求，来判断是否需要指示 ONU 进行波长切换。 比如， 当 OLT检测出其中只有极少数 ONU工作在某个波长 通道， 而其他波长通道仍具有带宽资源时， 基于节能需求考虑， OLT可以判 断出需要指示 ONU从原波长通道切换到具有带宽资源的波长通道，并关闭原 波长通道从而减低 TWDM-PON***的整体功耗， 实现节能。 It should be understood that, according to the load condition of the wavelength channel, whether the ONU is required to perform wavelength switching is only a basis for determining the load balancing requirement. In a specific implementation manner, the OLT may also be required for energy saving or optical transceiver replacement. To determine if you need to indicate ONU Perform wavelength switching. For example, when the OLT detects that only a very small number of ONUs are working in a certain wavelength channel, and other wavelength channels still have bandwidth resources, the OLT can determine that the ONU needs to be instructed to switch from the original wavelength channel to the bandwidth resource based on the energy saving requirement. The wavelength channel and the original wavelength channel are turned off to reduce the overall power consumption of the TWDM-PON system and achieve energy saving.
可选地， 当 OLT检测出某个光收发器件（比如下行光发射器或上行光接 收器） 出现故障或者性能劣化时， 可以判断出需要指示原工作在光收发器件 对应波长通道的 ONU切换到其他波长通道进行业务收发，以避免由于光收发 器件故障或性能劣化影响正常业务， 维护人员便可对出现故障或性能下降的 光收发器件进行更换。 另外， 在完成器件更换之后， OLT还可以根据需要指 示 ONU切换回原来的工作通道。  Optionally, when the OLT detects that a certain optical transceiver device (such as a downlink optical transmitter or an upstream optical receiver) is faulty or has performance degradation, it may be determined that the ONU that needs to indicate the original wavelength operation in the optical transceiver device is switched to Other wavelength channels perform service transmission and reception to avoid normal services due to optical transceiver failure or performance degradation, and maintenance personnel can replace optical transceivers with faults or performance degradation. In addition, after the device replacement is completed, the OLT can also indicate that the ONU switches back to the original working channel as needed.
需要说明的是， 上述歩骤 S301和歩骤 S302的执行顺序没有先后之分， 歩骤 S301和歩骤 S302也可以是同时执行的。  It should be noted that the execution order of the foregoing step S301 and step S302 is not sequential, and step S301 and step S302 may also be performed simultaneously.
歩骤 S303， OLT向 ONU发送波长切换命令。  Step S303: The OLT sends a wavelength switching command to the ONU.
具体地，所述波长切换命令用于指示所述 ONU从源波长通道切换到目的 波长通道， 其中， 所述波长切换命令携带开始时刻 t0， 用于指示所述 ONU在 to时刻开始从所述源波长通道切换到所述目的波长通道。  Specifically, the wavelength switching command is used to indicate that the ONU is switched from the source wavelength channel to the destination wavelength channel, where the wavelength switching command carries a start time t0, and is used to indicate that the ONU starts from the source at the time of to The wavelength channel is switched to the destination wavelength channel.
可选地， 波长切换命令携带目的波长通道的标识； 或携带目的波长通道 的上行波长和 /或下行波长； 或者携带目的波长通道的标识或目的波长通道的 上行波长和 /或下行波长， 以及波长切换类型信息， 所述波长切换类型信息用 于指示切换上行波长和 /或下行波长。  Optionally, the wavelength switching command carries the identifier of the destination wavelength channel; or carries the uplink wavelength and/or the downlink wavelength of the destination wavelength channel; or carries the identifier of the destination wavelength channel or the uplink wavelength and/or the downlink wavelength of the destination wavelength channel, and the wavelength Switching type information, the wavelength switching type information is used to indicate switching uplink wavelengths and/or downlink wavelengths.
具体地， ONU可以根据目的波长通道的标识信息或需要切换的目的上行 波长和 /或目的下行波长确定需要进行切换的目的波长通道。 因此 OLT 向 ONU发送的波长切换命令中包括目的波长通道的标识信息或目的波长通道 中的目的上行波长和 /或目的下行波长。 另外， 波长切换命令中还可以包括波 长切换类型信息，该波长切换类型信息用于指示 ONU同时进行上行和下行波 长的切换， 或者仅进行上行波长或下行波长的切换。  Specifically, the ONU may determine the destination wavelength channel that needs to be switched according to the identification information of the destination wavelength channel or the destination uplink wavelength and/or the destination downlink wavelength that needs to be switched. Therefore, the wavelength switching command sent by the OLT to the ONU includes the identification information of the destination wavelength channel or the destination upstream wavelength and/or the destination downstream wavelength in the destination wavelength channel. In addition, the wavelength switching command may further include a wavelength switching type information, where the wavelength switching type information is used to indicate that the ONU performs the switching of the uplink and downlink wavelengths simultaneously, or only the uplink wavelength or the downlink wavelength is switched.
OLT可以通过 PLOAM消息、 OMCI消息、 MPCP消息或者 OAM消息 其中之一承载向 ONU发送波长切换命令。具体消息格式如字段取值和字段长 度可以根据实际需要而定， 在其他替代实施例中， OLT也可以通过新定义的 消息承载向 ONU发送波长切换命令。 以采用 PLOAM消息来承载波长切换命令为例， PLOAM消息的消息格 式如图 4所示， 图 4为 PLOAM消息格式示意图。 PLOAM消息通常包括光 网络单元标识（ONU ID)字段、消息标识（Message ID)字段、序列号（Sequence No) 字段、 数据 （Data) 字段和完整性检査 （Integrity Check) 字段。 在本发 明实施例中， 波长切换类型信息以及目标波长通道的标识信息或者目标下行 接收波长信息等波长切换相关信息可以承载在 PLOAM消息的数据字段， 比 如， 波长切换命令可以采用如表 1所示格式。 The OLT may send a wavelength switching command to the ONU through one of a PLOAM message, an OMCI message, an MPCP message, or an OAM message. The specific message format, such as the field value and the field length, may be determined according to actual needs. In other alternative embodiments, the OLT may also send a wavelength switching command to the ONU through the newly defined message bearer. Taking the PLOAM message to carry the wavelength switching command as an example, the message format of the PLOAM message is shown in FIG. 4, and FIG. 4 is a schematic diagram of the PLOAM message format. The PLOAM message typically includes an Optical Network Unit Identity (ONU ID) field, a Message ID field, a Sequence No field, a Data field, and an Integrity Check field. In the embodiment of the present invention, the wavelength switching type information and the wavelength switching related information such as the target wavelength channel identifier information or the target downlink receiving wavelength information may be carried in the data field of the PLOAM message. For example, the wavelength switching command may be as shown in Table 1. format.
表 1  Table 1
Figure imgf000018_0001
Figure imgf000018_0001
需要说明的是， ONU向 OLT发送的波长切换时间信息可也以采用与图 4 和表 1所示的消息格式类似的消息格式。  It should be noted that the wavelength switching time information sent by the ONU to the OLT may also adopt a message format similar to the message format shown in FIG. 4 and Table 1.
可选地， 波长切换命令携带的开始时刻 t0可以为所述 OLT接收到所述 ONU发送的波长切换确认消息的时刻， 或者 t0时刻为所述 ONU接收到所述 波长切换命令的时刻。  Optionally, the start time t0 carried by the wavelength switching command may be the time when the OLT receives the wavelength switching acknowledgement message sent by the ONU, or the time t0 is the time when the ONU receives the wavelength switching command.
具体地， 在 OLT向 ONU发送波长切换命令后， OLT进一歩地还可以接 收 ONU发送的波长切换确认消息， 使 OLT获知 ONU接收到了波长切换命 令， 并且可以开始进行波长切换。 因此 OLT向 ONU发送的波长切换命令携 带的时刻 t0可以设置为 OLT接收到 ONU发送的波长切换确认消息的时刻。 也就是说， OLT设置的时刻 t0的意义在于， 当 OLT接收到 ONU发送波长切 换确认消息后，确认 ONU能够进行波长切换，再使 ONU开始进行波长切换， 这样可以确保 OLT从 t0时刻起， 间隔时间 T后发送的下行数据能够被 ONU 接收到， 从而提高***的可靠性。  Specifically, after the OLT sends the wavelength switching command to the ONU, the OLT can also receive the wavelength switching confirmation message sent by the ONU, so that the OLT knows that the ONU has received the wavelength switching command, and can start wavelength switching. Therefore, the time t0 carried by the OLT to the wavelength switching command sent by the ONU can be set to the time when the OLT receives the wavelength switching confirmation message sent by the ONU. That is to say, the meaning of the time t0 set by the OLT is that after the OLT receives the wavelength switching confirmation message sent by the ONU, it confirms that the ONU can perform wavelength switching, and then causes the ONU to start wavelength switching, thereby ensuring the interval of the OLT from time t0. The downlink data sent after time T can be received by the ONU, thereby improving the reliability of the system.
或者 OLT可以在向 ONU发送波长切换命令后， 不等待接收 ONU发送 的波长切换确认消息， 即将时刻 t0设置为 ONU接收到波长切换命令的时刻。 这样适用于紧急程度比较高的波长切换需求， OLT在认为 ONU接收到波长 切换命令时， 即开始在目的波长通道向 ONU发送下行数据，这样可以缩短波 长切换所需的时间。 Or the OLT may not wait to receive the ONU after sending the wavelength switching command to the ONU. The wavelength switching confirmation message, that is, the time t0 is set to the time when the ONU receives the wavelength switching command. This applies to the high-urgency wavelength switching requirement. When the OLT considers that the ONU receives the wavelength switching command, it starts to send downlink data to the ONU in the destination wavelength channel, which can shorten the time required for wavelength switching.
从上述两种 t0时刻的设置方法可以看出， OLT对于 t0时刻的设置可以 根据***可靠性和波长切换的紧急程度进行调节。  It can be seen from the above two t0 setting methods that the setting of the OLT for the t0 time can be adjusted according to the system reliability and the urgency of the wavelength switching.
歩骤 S304， ONU在 t0时刻， 从源波长通道切换到目的波长通道。  Step S304: The ONU switches from the source wavelength channel to the destination wavelength channel at time t0.
可选地， OLT在 t0时刻启动一个 "波长切换"计时器， 开始计时， 用于记 录波长切换的时间。  Optionally, the OLT starts a "wavelength switching" timer at time t0 to start timing for recording the time of wavelength switching.
歩骤 S305， OLT从 t0时刻起， 经过时间 T, 通过目的波长通道向 ONU 发送下行数据和上行时隙授权， 其中， 时间 T为 ONU从源波长通道切换到 目的波长通道所需时间。  Step S305: The OLT sends the downlink data and the uplink time slot authorization to the ONU through the destination wavelength channel from the time t0, and the time T is the time required for the ONU to switch from the source wavelength channel to the destination wavelength channel.
具体地， 在 TWDM-PON***中， 由于一个波长通道是通过 TDM的方 式使多个 ONU共享上行波长的， 因此对于 TWDM-PON***， OLT从 t0时 刻起， 经过时间 T, 通过目的波长通道向 ONU发送下行数据的同时， 还向 ONU发送上行时隙授权。即 OLT需要指示 ONU使用目的波长通道的上行时 隙。 而对于 WDM***， 若采用本实施例的波长切换方法， 则 OLT就不需要 想 ONU发送上行时隙授权。  Specifically, in a TWDM-PON system, since one wavelength channel is configured to allow a plurality of ONUs to share an upstream wavelength by means of TDM, for a TWDM-PON system, the OLT passes the time T through the destination wavelength channel from time t0. While transmitting the downlink data, the ONU also sends an uplink time slot grant to the ONU. That is, the OLT needs to instruct the ONU to use the upstream time slot of the destination wavelength channel. For the WDM system, if the wavelength switching method of this embodiment is adopted, the OLT does not need to want the ONU to send an uplink time slot grant.
歩骤 S306， OLT在本地存储器中存储下行数据。  Step S306, the OLT stores the downlink data in the local storage.
具体地， OLT在目的波长通道向 ONU发送下行数据以及上行时隙授权 之后， 还在本地存储器中存储该下行数据。 由于 OLT在向 ONU发送波长切 换命令后， 毕竟还未接收到 ONU发送的切换完成消息， 也就是说 OLT还没 有确认 ONU已经完成了波长切换， 由于信道错误或 ONU故障等原因， ONU 可能无法完成波长切换， 因此为了保证业务的完整性， OLT在目的波长通道 向 ONU下行数据以及上行时隙授权后， 还在本地存储器中存储该下行数据。  Specifically, after the OLT sends the downlink data and the uplink time slot authorization to the ONU in the destination wavelength channel, the OLT also stores the downlink data in the local memory. After the OLT sends a wavelength switching command to the ONU, the OLT has not received the handover completion message sent by the ONU. That is, the OLT has not confirmed that the ONU has completed the wavelength switching. The ONU may not be completed due to channel error or ONU failure. The wavelength is switched. Therefore, in order to ensure the integrity of the service, the OLT stores the downlink data in the local storage after the destination wavelength channel grants the ONU downlink data and the uplink time slot.
需要说明的是， 歩骤 S306可以和歩骤 S305同时执行。  It should be noted that step S306 can be performed simultaneously with step S305.
具体地， OLT仅在 ONU工作的目的波长通道上发送下行数据， 并进行 带宽授权， 即根据在目的波长通道上的业务情况进行动态带宽分配 (Dynannc Bandwidth Allocation, DBA)调度， 给 ONU授权上行发送时隙。  Specifically, the OLT transmits the downlink data only on the destination wavelength channel of the ONU, and performs bandwidth authorization, that is, performs dynamic bandwidth allocation (Danannc Bandwidth Allocation (DBA) scheduling according to the service condition on the destination wavelength channel, and authorizes the ONU to send uplink transmission. Time slot.
同时 OLT将在目的波长通道上给 ONU下发的数据同歩保存在本地存储 器中， 直到后续收到 ONU在 OLT 授权的时隙上发送来的上行数据或者是 ONU上报的 "波长切换完成"的消息。 At the same time, the OLT will save the data sent to the ONU on the destination wavelength channel in the local storage. In the device, the uplink data sent by the ONU on the OLT authorized time slot or the "wavelength switching completed" message reported by the ONU is received.
此外， 为了能够实现快速的波长切换， 光线路终端 OLT还可以让目的波 长通道的 MAC (Media Access Control)层在 ONU完成波长切换之前， 提前 在目的波长通道上为 ONU做好数据传输准备， 例如在目的波长通道的 MAC 层为 ONU准备好新的路由转发表， 提前准备好 ONU的下行发数据， 以及计 算好该 ONU的时隙授权， 以便于 OLT新的通道能够在 ONU刚好完成波长 切换的时刻就能立即在目的波长通道向其发送下行数据以及上行时隙授权。  In addition, in order to enable fast wavelength switching, the optical line terminal OLT can also prepare the MAC (Media Access Control) layer of the destination wavelength channel to prepare the data transmission for the ONU on the destination wavelength channel before the ONU completes the wavelength switching, for example. Prepare a new routing forwarding table for the ONU in the MAC layer of the destination wavelength channel, prepare the downlink data of the ONU in advance, and calculate the time slot authorization of the ONU, so that the new channel of the OLT can just complete the wavelength switching in the ONU. Immediately, the downlink data and the uplink time slot grant can be sent to the destination wavelength channel at any time.
歩骤 S307， ONU完成波长调节以后， 在目的波长通道上接收 OLT的下 行数据， 并根据下行数据中的 ONU的上行授权信息， 在 OLT授权的时隙向 OLT发送上行数据。  Step S307: After completing the wavelength adjustment, the ONU receives the downlink data of the OLT on the destination wavelength channel, and sends the uplink data to the OLT in the time slot authorized by the OLT according to the uplink authorization information of the ONU in the downlink data.
具体地，一般地，在 OLT向 ONU发送下行数据以及上行时隙授权之后， ONU就能够接收到 OLT发送的下行数据以及上行时隙授权。但若 ONU出现 故障或传输的通道出现故障等原因， ONU可能无法正常接收 OLT发送的下 行数据以及上行时隙授权。 因此 OLT为了能够与 ONU在目的波长通道正常 通信， OLT在目的波长通道向 ONU发送下行数据以及上行时隙授权之后， 若 ONU正常接收到了下行数据， ONU将在目的波长通道向 OLT发送波长切 换完成消息。 从而使 OLT确认 ONU已经切换至目的波长通道。  Specifically, in general, after the OLT sends the downlink data and the uplink time slot grant to the ONU, the ONU can receive the downlink data and the uplink time slot grant sent by the OLT. However, if the ONU fails or the transmission channel fails, the ONU may not receive the downlink data and the uplink time slot authorization sent by the OLT. Therefore, in order to enable the OLT to communicate with the ONU in the destination wavelength channel, the OLT sends the downlink data and the uplink time slot authorization to the ONU after the destination wavelength channel. If the ONU normally receives the downlink data, the ONU will send the wavelength switch to the OLT in the destination wavelength channel. Message. This allows the OLT to confirm that the ONU has switched to the destination wavelength channel.
此外， ONU还可以在给 OLT发送的上行数据中， 发送一个" ONU波长 切换完成确认"消息， 告知上行波长切换已经切换成功。  In addition, the ONU may send an "ONU Wavelength Switching Complete Confirmation" message to the uplink data sent by the OLT to inform the uplink wavelength switching that the handover has been successful.
在具体实施例中，所述波长切换完成确认同样也可以通过 PLOAM消息、 OMCI消息、 MPCP消息、 OAM消息或者其他新定义的消息进行承载。  In a specific embodiment, the wavelength switch completion confirmation may also be carried by a PLOAM message, an OMCI message, an MPCP message, an OAM message, or other newly defined message.
此外， 为了避免 ONU在上行波长切换时， 在 ONU本身不知情的情况下 发生了故障， 将上行波长切换到了非目的上行波长， 然后在非目的上行波长 上利用目的上行波长的时隙向 OLT发送上行数据以及消息，从而造成对其他 波长通道的干扰。 例如 OLT指示 ONU将上行波长从 λιιΐ切换到 λιι2， 但是 ONU由于光模块器件发生了故障， 其发射机将发射波长误调节到了 λιι3或者 其他通道波长的通带内了，这将会导致 ONU会以 λιι3在 λιι2对应的波长通道 的授权时隙内发送上行数据，这样就会干扰在 λιι3上正常工作的 ONU的通信。  In addition, in order to prevent the ONU from switching in the uplink wavelength, the ONU itself fails to know the fault, and the uplink wavelength is switched to the non-destination uplink wavelength, and then the non-destination uplink wavelength is used to transmit to the OLT by using the destination uplink wavelength slot. Uplink data and messages, causing interference to other wavelength channels. For example, the OLT instructs the ONU to switch the upstream wavelength from λιΐ to λιι2. However, due to the failure of the optical module device, the transmitter mis-adjusts the emission wavelength to the passband of λιι3 or other channel wavelengths, which will cause the ONU to Λιι3 sends uplink data in the authorized time slot of the wavelength channel corresponding to λιι2, which interferes with the communication of the ONU working normally on λιι3.
为了加强***可靠性，避免这种可能因为 ONU器件故障而干扰其他 ONU 的情况， OLT从 t0时刻起， 间隔时间 T， 在目的波长通道向 ONU发送下行 数据以及上行时隙授权的同时， 可选的， OLT在其他的多个波长通道上同时 将这个上行时隙预留出来， 并授权给该 ONU, 以避免 ONU可能在这个时隙 以他的波长发送数据， 从而和其他通道上的其他 ONU发生干扰， 即 OLT在 多个波长通道为 ONU分配相同的上行时隙，此时所有的波长通道上，该上行 时隙只分配给了该 ONU。当 OLT在目的波长通道接收到 ONU发送的上行数 据或波长切换完成消息后，确认 ONU已经切换到了目的波长通道，此时 OLT 停止目的波长之外的其他波长通道中与上行时隙授权中的上行时隙对应的上 行时隙对 ONU的授权。 这样可以进一歩地提高***可靠性， 避免 ONU的切 换对其他 ONU产生影响。 In order to enhance system reliability, avoid this possibility of interfering with other ONUs due to ONU device failure. In the case where the OLT transmits the downlink data and the uplink time slot grant to the ONU from the time t0, the interval time T, optionally, the OLT pre-stages the uplink time slot on the other multiple wavelength channels. Leave it and authorize it to the ONU to prevent the ONU from transmitting data at its wavelength in this time slot, thus interfering with other ONUs on other channels. That is, the OLT allocates the same uplink time slot to the ONU in multiple wavelength channels. At this time, on all wavelength channels, the uplink time slot is only allocated to the ONU. After the OLT receives the uplink data or the wavelength switch completion message sent by the ONU in the destination wavelength channel, it confirms that the ONU has switched to the destination wavelength channel. At this time, the OLT stops the uplink in the other wavelength channels except the destination wavelength and the uplink time slot authorization. Authorization of the ONU by the uplink time slot corresponding to the time slot. This can further improve system reliability and prevent ONU switching from affecting other ONUs.
此种办法通过浪费了一定的其他波长通道上的上行带宽， 从而提高了系 统的可靠性。 实际情况中， 可以根据实际需要以及实际器件、 ***的可靠性 来选择是否需要在所有的波长通道上为网络单元 120进行上行时隙授权。  This approach increases the reliability of the system by wasting the upstream bandwidth on certain other wavelength channels. In actual situations, whether uplink time slot authorization for the network unit 120 needs to be performed on all wavelength channels can be selected according to actual needs and actual device and system reliability.
歩骤 S308， OLT在目的波长通道收到 ONU发送的上行数据或者切换完 成消息后， 停止在本地存储器中存储下行数据， 并释放本地存储器中存储的 下行数据， 同时停止波长切换计时器， 并将其记录的时间清零。  Step S308, after receiving the uplink data or the handover complete message sent by the ONU, the OLT stops storing the downlink data in the local memory, and releases the downlink data stored in the local memory, and stops the wavelength switching timer, and stops the wavelength switching timer. The recorded time is cleared.
具体地， 当 OLT在目的波长通道接收到 ONU发送的波长切换完成消息 后， 确认 ONU已经接收到了本地存储器中存储的下行数据， 则 OLT可以释 放本地存储器中存储的下行数据。  Specifically, after the OLT receives the wavelength switch completion message sent by the ONU in the destination wavelength channel, and confirms that the ONU has received the downlink data stored in the local memory, the OLT can release the downlink data stored in the local memory.
可选地， OLT释放本地存储器中存储的下行数据的触发条件还可以是： 当 OLT在目的波长通道接收到 ONU发送的上行数据。当 OLT在目的波长通 道接收到 ONU发送的上行数据， 则 OLT同样可以确认 ONU已经完成了波 长切换， 因此可以释放本地存储器中存储的下行数据。  Optionally, the triggering condition for the OLT to release the downlink data stored in the local storage may be: when the OLT receives the uplink data sent by the ONU in the destination wavelength channel. When the OLT receives the uplink data sent by the ONU on the destination wavelength channel, the OLT can also confirm that the ONU has completed the wavelength switching, so that the downlink data stored in the local memory can be released.
进一歩地， OLT在目的波长通道接收到 ONU发送的上行数据或波长切 换完成消息之后， 还包括： OLT 向 ONU发送波长切换完成确认消息。 OLT 在确认 ONU完成波长切换后， 还可以通知 ONU已经完成波长切换的确认消 息。  Further, after the OLT receives the uplink data or the wavelength switch completion message sent by the ONU in the destination wavelength channel, the OLT further includes: the OLT sends a wavelength switch completion confirmation message to the ONU. After confirming that the ONU completes the wavelength switching, the OLT can also notify the ONU that the confirmation message of the wavelength switching has been completed.
进一歩地， OLT在本地存储器中存储在目的波长通道向 ONU发送的下 行数据之后， 还包括： 当 OLT在预设的波长切换定时时间后仍未在目的波长 通道接收到 ONU发送的上行数据或波长切换完成消息时， OLT在源波长通 道向 ONU发送本地存储器中存储的下行数据，或者 OLT在 OLT恢复与 ONU 的通信通道之后， 重新向 ONU发送本地存储器中存储的下行数据。 Further, after the OLT stores the downlink data sent by the destination wavelength channel to the ONU in the local storage, the OLT further includes: after the preset time of the preset wavelength switching, the OLT does not receive the uplink data sent by the ONU in the destination wavelength channel or When the wavelength switching completion message is received, the OLT passes through the source wavelength. The channel sends the downlink data stored in the local storage to the ONU, or the OLT retransmits the downlink data stored in the local storage to the ONU after the OLT resumes the communication channel with the ONU.
具体地， 在 OLT中设置有一个波长切换定时器， 当 OLT向 ONU发送波 长切换命令后， OLT将启动该波长切换定时器， OLT在波长切换定时器未超 时之前接收到 ONU发送的上行数据或者波长切换完成消息都代表 ONU已经 完成波长切换。 当 OLT在目的波长通道向 ONU发送下行数据以及上行时隙 授权后， 并且在预设的波长切换定时时间后 （即波长定时器超时后） 仍未在 目的波长通道接收到 ONU发送的上行数据或波长切换完成消息时， 则 OLT 将确定 ONU的波长切换失败。此时为了保证业务的完整性，OLT将等待 ONU 重新回滚到源波长通道，并在源波长通道向 ONU发送本地存储器中存储的下 行数据。 或者 OLT在 OLT恢复与 ONU的通信通道之后， 重新向 ONU发送 本地存储器中存储的下行数据。  Specifically, a wavelength switching timer is set in the OLT. After the OLT sends a wavelength switching command to the ONU, the OLT starts the wavelength switching timer, and the OLT receives the uplink data sent by the ONU before the wavelength switching timer expires. The wavelength switching completion message indicates that the ONU has completed wavelength switching. After the OLT sends the downlink data and the uplink time slot authorization to the ONU in the destination wavelength channel, and after the preset wavelength switching timing time (that is, after the wavelength timer expires), the OLT still does not receive the uplink data sent by the ONU on the destination wavelength channel or When the wavelength switching completion message is received, the OLT will determine that the wavelength switching of the ONU has failed. At this time, in order to ensure the integrity of the service, the OLT will wait for the ONU to roll back to the source wavelength channel, and send the downlink data stored in the local storage to the ONU on the source wavelength channel. Or the OLT resends the downlink data stored in the local memory to the ONU after the OLT restores the communication channel with the ONU.
当 OLT在预设的波长切换定时时间后未在目的波长通道接收到 ONU发 送的上行数据或波长切换完成消息时， OLT在 ONU回落到源波长通道后， 在源波长通道向 ONU发送本地存储器中存储的下行数据，或者 OLT在 ONU 重新注册后， 在 ONU重新注册的波长通道上重新向 ONU发送本地存储器中 存储的下行数据。  When the OLT does not receive the uplink data or the wavelength switch completion message sent by the ONU in the destination wavelength channel after the preset wavelength switching time, the OLT sends the local memory to the ONU in the source wavelength channel after the ONU falls back to the source wavelength channel. The stored downlink data, or after the OLT re-registers with the ONU, re-sends the downlink data stored in the local memory to the ONU on the wavelength channel re-registered by the ONU.
需要说明的是， 本实施例提供的波长切换方法不仅适用于 TWDM-PON ***， 还可以适用于 WDM-PON***等具有多波长的光通信***。  It should be noted that the wavelength switching method provided in this embodiment is applicable not only to the TWDM-PON system but also to an optical communication system having multiple wavelengths such as a WDM-PON system.
实施例三  Embodiment 3
图 5为本发明实施例提供的用于波长切换的装置的结构示意图， 如图 5 所示， 本实施例提供的用于波长切换的装置 50包括：  FIG. 5 is a schematic structural diagram of an apparatus for wavelength switching according to an embodiment of the present invention. As shown in FIG. 5, the apparatus 50 for wavelength switching provided by this embodiment includes:
处理单元 51， 用于生成波长切换命令， 并指示向 ONU发送所述波长切 换命令，所述波长切换命令用于指示所述 ONU从源波长通道切换到目的波长 通道， 其中， 所述波长切换命令携带开始时刻 t0， 所述 t0用于指示所述 ONU 在 to时刻开始从所述源波长通道切换到所述目的波长通道； 还用于指示在从 所述 t0时刻起经过时间 T的时刻， 开始通过所述目的波长通道向所述 ONU 发送下行数据。  The processing unit 51 is configured to generate a wavelength switching command, and instruct to send the wavelength switching command to the ONU, where the wavelength switching command is used to instruct the ONU to switch from the source wavelength channel to the destination wavelength channel, where the wavelength switching command Carrying a start time t0, the t0 is used to indicate that the ONU starts to switch from the source wavelength channel to the destination wavelength channel at the time of to; and is further configured to indicate that the time T is elapsed from the time t0, start Transmitting downlink data to the ONU through the destination wavelength channel.
可选地， 所述装置还包括：  Optionally, the device further includes:
发送单元 52， 用于根据处理单元的指示向 ONU发送波长切换命令； 从 所述 tO时刻起， 经过时间 T, 通过所述目的波长通道向所述 ONU发送下行 数据， 其中， 所述时间 T为所述 ONU从所述源波长通道切换到所述目的波 长通道所需时间。 The sending unit 52 is configured to send a wavelength switching command to the ONU according to the indication of the processing unit; The time T is sent to the ONU through the destination wavelength channel, and the time T is the time required for the ONU to switch from the source wavelength channel to the destination wavelength channel. .
具体地，所述波长切换命令用于指示所述 ONU从源波长通道切换到目的 波长通道， 其中， 所述波长切换命令携带开始时刻 t0， 用于指示所述 ONU在 to时刻开始从所述源波长通道切换到所述目的波长通道。  Specifically, the wavelength switching command is used to indicate that the ONU is switched from the source wavelength channel to the destination wavelength channel, where the wavelength switching command carries a start time t0, and is used to indicate that the ONU starts from the source at the time of to The wavelength channel is switched to the destination wavelength channel.
可选地， 波长切换命令携带目的波长通道的标识； 或携带目的波长通道 的上行波长和 /或下行波长； 或者携带目的波长通道的标识或目的波长通道的 上行波长和 /或下行波长， 以及波长切换类型信息， 所述波长切换类型信息用 于指示切换上行波长和 /或下行波长。  Optionally, the wavelength switching command carries the identifier of the destination wavelength channel; or carries the uplink wavelength and/or the downlink wavelength of the destination wavelength channel; or carries the identifier of the destination wavelength channel or the uplink wavelength and/or the downlink wavelength of the destination wavelength channel, and the wavelength Switching type information, the wavelength switching type information is used to indicate switching uplink wavelengths and/or downlink wavelengths.
具体地， ONU可以根据目的波长通道的标识信息或需要切换的目的上行 波长和 /或目的下行波长确定需要进行切换的目的波长通道。 因此 OLT 向 ONU发送的波长切换命令中包括目的波长通道的标识信息或目的波长通道 中的目的上行波长和 /或目的下行波长。 另外， 波长切换命令中还可以包括波 长切换类型信息，该波长切换类型信息用于指示 ONU同时进行上行和下行波 长的切换， 或者仅进行上行波长或下行波长的切换。  Specifically, the ONU may determine the destination wavelength channel that needs to be switched according to the identification information of the destination wavelength channel or the destination uplink wavelength and/or the destination downlink wavelength that needs to be switched. Therefore, the wavelength switching command sent by the OLT to the ONU includes the identification information of the destination wavelength channel or the destination upstream wavelength and/or the destination downstream wavelength in the destination wavelength channel. In addition, the wavelength switching command may further include a wavelength switching type information, where the wavelength switching type information is used to indicate that the ONU performs the switching of the uplink and downlink wavelengths simultaneously, or only the uplink wavelength or the downlink wavelength is switched.
OLT可以通过 PLOAM消息、 OMCI消息、 MPCP消息或者 OAM消息 其中之一承载向 ONU发送波长切换命令。具体消息格式如字段取值和字段长 度可以根据实际需要而定， 在其他替代实施例中， OLT也可以通过新定义的 消息承载向 ONU发送波长切换命令。  The OLT may send a wavelength switching command to the ONU through one of a PLOAM message, an OMCI message, an MPCP message, or an OAM message. The specific message format, such as the field value and the field length, may be determined according to actual needs. In other alternative embodiments, the OLT may also send a wavelength switching command to the ONU through the newly defined message bearer.
以采用 PLOAM消息来承载波长切换命令为例， PLOAM消息的消息格 式如图 4所示， 图 4为 PLOAM消息格式示意图。 PLOAM消息通常包括光 网络单元标识（ONU ID)字段、消息标识（Message ID)字段、序列号（Sequence No) 字段、 数据 （Data) 字段和完整性检査 （Integrity Check) 字段。 在本发 明实施例中， 波长切换类型信息以及目标波长通道的标识信息或者目标下行 接收波长信息等波长切换相关信息可以承载在 PLOAM消息的数据字段， 比 如， 波长切换命令可以采用如表 1所示格式。  Taking the PLOAM message to carry the wavelength switching command as an example, the message format of the PLOAM message is shown in FIG. 4, and FIG. 4 is a schematic diagram of the PLOAM message format. The PLOAM message typically includes an Optical Network Unit Identity (ONU ID) field, a Message ID field, a Sequence No field, a Data field, and an Integrity Check field. In the embodiment of the present invention, the wavelength switching type information and the wavelength switching related information such as the target wavelength channel identifier information or the target downlink receiving wavelength information may be carried in the data field of the PLOAM message. For example, the wavelength switching command may be as shown in Table 1. format.
本实施例的用于波长切换的装置用于执行上述实施例一中 OLT侧的技术 方案， 其实现原理和技术效果类似， 此处不再赘述。  The device for wavelength switching in this embodiment is used to perform the technical solution on the OLT side in the first embodiment, and the implementation principle and technical effects are similar, and details are not described herein again.
可选的， 用于波长切换的装置 50还包括： 接收单元 53， 用于获取所述 时间 τ。 Optionally, the device 50 for wavelength switching further includes: a receiving unit 53, configured to acquire the Time τ.
OLT获取 ONU进行波长切换所需要的时间 T的方法有多种， 例如 ONU 在注册时或者注册后向 OLT上报该 ONU从源波长通道 （不妨设其上下行波 长分别为 λιιΐ , λάΐ )切换到目的波长通道（不妨设其上下行波长分别为 λιι2， λά2 ) 过程所需要的时间 Τ。  There are various methods for the OLT to obtain the time T required for the ONU to perform wavelength switching. For example, the ONU reports to the OLT during registration or registration, and the ONU switches from the source wavelength channel (may set its uplink and downlink wavelengths to λιιΐ, λάΐ respectively) to the destination. The time required for the wavelength channel (may be set to λιι2, λά2 for the upstream and downstream wavelengths respectively).
具体可以是 OLT接收到 ONU发送的波长切换时间消息， 该波长切换时 间消息携带时间 T， OLT从波长切换时间消息中获取该时间 Τ, 这种方法适 用于新注册的 ONU或者 OLT中没有保存 ONU进行波长切换所需要的时间 Τ 的情况。  Specifically, the OLT receives the wavelength switching time message sent by the ONU, where the wavelength switching time message carries the time T, and the OLT obtains the time 从 from the wavelength switching time message. The method is applicable to the newly registered ONU or the OLT does not save the ONU. The time Τ required for wavelength switching.
OLT还可以从本地存储器中读取存储的该 ONU进行波长切换所需的时 间 Τ， 存储器中存储的时间 Τ可以是 ONU之前向 OLT发送的， 或者可以是 OLT根据 ONU发送的其他信息计算得出的， 或者可以是通过命令行或网管 ***人工输入的。  The OLT can also read the time required for the ONU to perform wavelength switching from the local storage. The time stored in the memory can be sent to the OLT before the ONU, or can be calculated by the OLT according to other information sent by the ONU. Or, it can be manually entered through the command line or the network management system.
进一歩地， ONU 可以通过物理层操作管理和维护 （Physical Layer Operations Administration and Maintenance, PLOAM) 消息、 光网络终端管理 和控制接口 （ONT Management and Control Interface, OMCI) 消息、 多点控 制协议 （Multi-Point Control Protocols , MPCP ) 消息或者操作管理和维护 (Operation Administration and Maintenance, OAM) 消息其中的任意一禾中来 承载上述 ONU向 OLT发送的波长切换时间消息。在其他替代实施例中，ONU 也可以通过新定义的消息来承载向 OLT发送的波长切换时间信息。  Further, the ONU can pass the Physical Layer Operations Administration and Maintenance (PLOAM) message, the Optical Network Terminal Management and Control Interface (OMCI) message, and the Multipoint Control Protocol (Multi- The Point Control Protocols (MPCP) message or any of the Operation Management and Maintenance (OAM) messages carries the wavelength switch time message sent by the ONU to the OLT. In other alternative embodiments, the ONU may also carry the wavelength switching time information sent to the OLT through the newly defined message.
以采用 PLOAM消息来承载波长切换时间消息为例， PLOAM消息的消 息格式如图 4所示， 图 4为 PLOAM消息格式示意图。 PLOAM消息通常包 括光网络单元标识 （ONU ID) 字段、 消息标识 （Message ID) 字段、 序列号 ( Sequence No) 字段、 数据 （Data) 字段和完整性检査 （Integrity Check) 字 段。 在本发明实施例中， 波长切换时间信息可以承载在 PLOAM消息的数据 字段。  Taking the PLOAM message to carry the wavelength switching time message as an example, the message format of the PLOAM message is shown in FIG. 4, and FIG. 4 is a schematic diagram of the PLOAM message format. PLOAM messages typically include an Optical Network Unit Identification (ONU ID) field, a Message ID (Message ID) field, a Sequence Number field, a Data field, and an Integrity Check field. In the embodiment of the present invention, the wavelength switching time information may be carried in a data field of a PLOAM message.
可选的， 用于波长切换的装置 50还包括： 存储单元 54， 用于在本地存 储器中存储所述下行数据。  Optionally, the device 50 for wavelength switching further includes: a storage unit 54 configured to store the downlink data in the local storage.
可选的， 处理单元 51， 还用于确定指示 ONU从源波长通道切换到目的 波长通道。 具体地， OLT向 ONU发送波长切换命令之前， 还需要确定是否需要指 示 ONU从源波长通道切换到目的波长通道。 OLT确定指示 ONU从源波长通 道切换到目的波长通道的依据有多种情况， 包括： 若所述源波长通道的负载 超过预设的过载阈值且所述目的波长通道的负载未超过预设的过载阈值， 则 所述 OLT确定指示所述 ONU从所述源波长通道切换到所述目的波长通道； 或者若所述原波长通道的负载低于预设的轻载阈值且所述目的波长通道的负 载未超过预设的过载阈值， 则所述 OLT确定指示所述 ONU从所述源波长通 道切换到所述目的波长通道； 或者若所述源波长通道对应的光收发器件出现 故障或性能低于预设性能阈值， 则所述 OLT确定指示所述 ONU从所述源波 长通道切换到所述目的波长通道。 Optionally, the processing unit 51 is further configured to determine that the ONU is switched from the source wavelength channel to the destination wavelength channel. Specifically, before the OLT sends the wavelength switching command to the ONU, it is also required to determine whether the ONU needs to be switched from the source wavelength channel to the destination wavelength channel. The OLT determines that the ONU switches from the source wavelength channel to the destination wavelength channel according to various situations, including: if the load of the source wavelength channel exceeds a preset overload threshold and the load of the destination wavelength channel does not exceed a preset overload a threshold, the OLT determines to indicate that the ONU is switched from the source wavelength channel to the destination wavelength channel; or if the load of the original wavelength channel is lower than a preset light load threshold and the load of the destination wavelength channel If the preset overload threshold is not exceeded, the OLT determines to indicate that the ONU switches from the source wavelength channel to the destination wavelength channel; or if the optical transceiver device corresponding to the source wavelength channel fails or the performance is lower than the pre- Setting a performance threshold, the OLT determines to instruct the ONU to switch from the source wavelength channel to the destination wavelength channel.
OLT可以实时检测 TWDM-PON***中的各个波长通道的上下行业务负 载情况， 用以判断是否需要进行波长切换。 当检测出 TWDM-PON***出现 波长通道负载不均衡时， 比如， 当波长通道 1下行负载过重， 波长通道 2下 行负载较轻， 而波长通道 3和 4下行负载正常时， OLT可以判断出需要指示 原来工作在波长通道 1的 ONU切换到波长通道 2进行下行业务接收，即此时 OLT可以判断出需要指示此部分 ONU将其下行接收波长从波长通道 1的下 行波长切换到波长通道 2的下行波长。  The OLT can detect the uplink and downlink traffic load of each wavelength channel in the TWDM-PON system in real time to determine whether wavelength switching is required. When the wavelength channel load imbalance of the TWDM-PON system is detected, for example, when the downlink load of the wavelength channel 1 is too heavy, the downlink load of the wavelength channel 2 is light, and when the downlink load of the wavelength channels 3 and 4 is normal, the OLT can determine the need. Indicates that the ONU that is working in the wavelength channel 1 switches to the wavelength channel 2 for downlink service reception. That is, the OLT can determine that the ONU needs to instruct the ONU to switch its downlink receiving wavelength from the downstream wavelength of the wavelength channel 1 to the downstream of the wavelength channel 2. wavelength.
应当理解，上述根据波长通道的负载情况来判断是否需要指示 ONU进行 波长切换只是为了实现负载均衡需求的一种判断依据， 在具体实施方式中， OLT还可以出于节能或者光收发器件更换的需求，来判断是否需要指示 ONU 进行波长切换。 比如， 当 OLT检测出其中只有极少数 ONU工作在某个波长 通道， 而其他波长通道仍具有带宽资源时， 基于节能需求考虑， OLT可以判 断出需要指示 ONU从原波长通道切换到具有带宽资源的波长通道，并关闭原 波长通道从而减低 TWDM-PON***的整体功耗， 实现节能。  It should be understood that, according to the load condition of the wavelength channel, whether the ONU is required to perform wavelength switching is only a basis for determining the load balancing requirement. In a specific implementation manner, the OLT may also be required for energy saving or optical transceiver replacement. To determine if the ONU needs to be instructed to perform wavelength switching. For example, when the OLT detects that only a very small number of ONUs are working in a certain wavelength channel, and other wavelength channels still have bandwidth resources, the OLT can determine that the ONU needs to be instructed to switch from the original wavelength channel to the bandwidth resource based on the energy saving requirement. The wavelength channel and the original wavelength channel are turned off to reduce the overall power consumption of the TWDM-PON system and achieve energy saving.
可选地， 当 OLT检测出某个光收发器件（比如下行光发射器或上行光接 收器） 出现故障或者性能劣化时， 可以判断出需要指示原工作在光收发器件 对应波长通道的 ONU切换到其他波长通道进行业务收发，以避免由于光收发 器件故障或性能劣化影响正常业务， 维护人员便可对出现故障或性能下降的 光收发器件进行更换。 另外， 在完成器件更换之后， OLT还可以根据需要指 示 ONU切换回原来的工作通道。 所述处理单元 51， 还用于当 OLT在所述目的波长通道接收到所述 ONU 发送的上行数据或波长切换完成消息时， 释放所述本地存储器中存储的下行 数据。 Optionally, when the OLT detects that a certain optical transceiver device (such as a downlink optical transmitter or an upstream optical receiver) is faulty or has performance degradation, it may be determined that the ONU that needs to indicate the original wavelength operation in the optical transceiver device is switched to Other wavelength channels perform service transmission and reception to avoid normal services due to optical transceiver failure or performance degradation, and maintenance personnel can replace optical transceivers with faults or performance degradation. In addition, after the device replacement is completed, the OLT can also instruct the ONU to switch back to the original working channel as needed. The processing unit 51 is further configured to: when the OLT receives the uplink data or the wavelength switch completion message sent by the ONU in the destination wavelength channel, release the downlink data stored in the local memory.
可选的，发送单元 52，还用于当所述 OLT在预设的波长切换定时时间后 未在所述目的波长通道接收到所述 ONU发送的上行数据或波长切换完成消 息时，在所述 ONU回落到所述源波长通道后，在所述源波长通道向所述 ONU 发送所述本地存储器中存储的所述下行数据， 或者在所述 ONU重新注册后， 在所述 ONU重新注册的波长通道上重新向所述 ONU发送所述本地存储器中 存储的所述下行数据。  Optionally, the sending unit 52 is further configured to: when the OLT does not receive the uplink data or the wavelength switching complete message sent by the ONU in the destination wavelength channel after the preset wavelength switching timing time, After the ONU falls back to the source wavelength channel, the downlink data stored in the local memory is sent to the ONU in the source wavelength channel, or the wavelength re-registered in the ONU after the ONU is re-registered. The downlink data stored in the local storage is retransmitted to the ONU on the channel.
可选的， 发送单元 52， 还用于从所述 t0时刻起， 经过所述时间 T, 通过 所述目的波长通道向所述 ONU发送上行时隙授权  Optionally, the sending unit 52 is further configured to send an uplink time slot authorization to the ONU by using the destination wavelength channel after the time T from the time t0.
可选的， 用于波长切换的装置 50中， 所述波长切换命令携带所述目的波 长通道的标识或所述目的波长通道的上行波长和 /或下行波长； 或者所述波长 切换命令携带所述目的波长通道的标识或所述目的波长通道的上行波长和 / 或下行波长， 以及波长切换类型信息， 所述波长切换类型信息包括切换上行 波长和 /或下行波长的指示信息。  Optionally, in the device 50 for wavelength switching, the wavelength switching command carries an identifier of the destination wavelength channel or an uplink wavelength and/or a downlink wavelength of the destination wavelength channel; or the wavelength switching command carries the The identifier of the destination wavelength channel or the uplink wavelength and/or the downlink wavelength of the destination wavelength channel, and the wavelength switching type information, where the wavelength switching type information includes indication information for switching the uplink wavelength and/or the downlink wavelength.
实施例四  Embodiment 4
图 6为本发明实施例提供的用于波长切换的另一装置的结构示意图， 如 图 6所示， 本实施例提供的用于波长切换的装置 60包括：  FIG. 6 is a schematic structural diagram of another apparatus for wavelength switching according to an embodiment of the present invention. As shown in FIG. 6, the apparatus 60 for wavelength switching provided by this embodiment includes:
发送单元 61，用于向 OLT发送波长切换时间消息，所述波长切换时间消 息携带时间 T,所述时间 T为 ONU从源波长通道切换到目的波长通道所需时 间， 所述 T用于指示所述 OLT的等待时间， 所述等待时间是指从所述 ONU 开始波长切换到所述 OLT开始下发下行数据之间的等待时间；  The sending unit 61 is configured to send a wavelength switching time message to the OLT, where the wavelength switching time message carries a time T, where the time T is a time required for the ONU to switch from the source wavelength channel to the destination wavelength channel, where the T is used to indicate the location The waiting time of the OLT is the waiting time between the wavelength switching from the ONU and the downlink data sent by the OLT.
接收单元 63，用于接收 OLT发送的波长切换命令，所述波长切换命令用 于指示 ONU从源波长通道切换到目的波长通道，其中，所述波长切换命令携 带开始时刻 t0， 用于指示所述 ONU在 t0时刻开始从所述源波长通道切换到 所述目的波长通道；  The receiving unit 63 is configured to receive a wavelength switching command sent by the OLT, where the wavelength switching command is used to instruct the ONU to switch from the source wavelength channel to the destination wavelength channel, where the wavelength switching command carries a starting time t0, and is used to indicate the The ONU starts to switch from the source wavelength channel to the destination wavelength channel at time t0;
处理单元 62， 用于在所述 t0时刻， 从所述源波长通道切换到所述目的波 长通道；  The processing unit 62 is configured to switch from the source wavelength channel to the destination wavelength channel at the time t0;
接收单元 63， 还用于在切换到所述目的波长通道后， 通过所述目的波长 通道接收所述 OLT发送的下行数据。 The receiving unit 63 is further configured to pass the target wavelength after switching to the destination wavelength channel The channel receives downlink data sent by the OLT.
本实施例的用于波长切换的装置用于执行上述实施例一中 ONU侧的技 术方案， 其实现原理和技术效果类似， 此处不再赘述。  The device for wavelength switching in this embodiment is used to perform the technical solution on the ONU side in the first embodiment, and the implementation principle and technical effects are similar, and details are not described herein again.
可选的， 接收单元 63， 还用于从所述 t0时刻起， 经过时间 T, 通过所述 目的波长通道接收所述 OLT发送的上行时隙授权。  Optionally, the receiving unit 63 is further configured to receive, by using the time T from the time t0, the uplink time slot authorization sent by the OLT by using the destination wavelength channel.
可选的， 用于波长切换的装置 60中， 所述波长切换命令携带所述目的波 长通道的标识或所述目的波长通道的上行波长和 /或下行波长； 或者所述波长 切换命令携带所述目的波长通道的标识或所述目的波长通道的上行波长和 / 或下行波长， 以及波长切换类型信息， 所述波长切换类型信息包括切换上行 波长和 /或下行波长的指示信息。  Optionally, in the device 60 for wavelength switching, the wavelength switching command carries an identifier of the destination wavelength channel or an uplink wavelength and/or a downlink wavelength of the destination wavelength channel; or the wavelength switching command carries the The identifier of the destination wavelength channel or the uplink wavelength and/or the downlink wavelength of the destination wavelength channel, and the wavelength switching type information, where the wavelength switching type information includes indication information for switching the uplink wavelength and/or the downlink wavelength.
实施例五  Embodiment 5
本发明实施例还公开了一种光线路终端， 图 7为本发明实施例提供的一 种 OLT的结构示意图， 如图 7所示， 本实施例提供的 OLT70包括光耦合器 71、 第一波分复用器 72、 第二波分复用器 73、 多个下行光发射器 Txl~Tx4、 多个上行光接收器 Rxl~Rx4和处理器 74。 其中， 光耦合器 71、 第一波分复 用器 72、 第二波分复用器 73、 多个下行光发射器 Txl~Tx4、 多个上行光接收 器 Rxl~Rx4与图 1所示的 OLT110中的相应模块类似， 处理器 74可以用于 执行如实施例一或实施二中 OLT侧的方法。  The embodiment of the present invention further discloses an optical line terminal. FIG. 7 is a schematic structural diagram of an OLT according to an embodiment of the present invention. As shown in FIG. 7, the OLT 70 provided in this embodiment includes an optical coupler 71 and a first wave. The sub-multiplexer 72, the second wavelength division multiplexer 73, the plurality of downstream optical transmitters Tx1 to Tx4, the plurality of upstream optical receivers Rx1 to Rx4, and the processor 74. The optical coupler 71, the first wavelength division multiplexer 72, the second wavelength division multiplexer 73, the plurality of downlink optical transmitters Tx1 to Tx4, and the plurality of upstream optical receivers Rx1 to Rx4 are as shown in FIG. The corresponding modules in the OLT 110 are similar, and the processor 74 can be used to perform the method on the OLT side as in the first or second embodiment.
实施例六  Embodiment 6
本发明实施例还公开了一种光网络单元， 图 8为本发明实施例提供的一 种 ONU的结构示意图， 如图 8所示， 本实施例提供的 ONU80包括光耦合器 81、 下行光接收器 82、 上行光发射器 83和处理器 84。 其中， 光耦合器 81、 下行光接收器 82、 上行光发射器 83与图 1所示的 ONU120中的相应模块类 似， 处理器 84可以用于执行如实施一或实施例二中 ONU侧的方法。  The embodiment of the present invention further discloses an optical network unit. FIG. 8 is a schematic structural diagram of an ONU according to an embodiment of the present invention. As shown in FIG. 8, the ONU 80 provided in this embodiment includes an optical coupler 81 and downlink optical reception. The transmitter 82, the upstream light transmitter 83 and the processor 84. The optical coupler 81, the downstream optical receiver 82, and the upstream optical transmitter 83 are similar to the corresponding modules in the ONU 120 shown in FIG. 1. The processor 84 can be used to perform the method on the ONU side as in the first embodiment or the second embodiment. .
实施例七  Example 7
本发明实施例还公开了一种无源光网络***， 包括 OLT和 ONU, OLT 通过 ODN连接至少一个 ONU, 其中 OLT包括如图 7所示的 OLT, ONU包 括如图 8所示的 ONU。  The embodiment of the present invention further discloses a passive optical network system, including an OLT and an ONU. The OLT connects at least one ONU through an ODN. The OLT includes an OLT as shown in FIG. 7, and the ONU includes an ONU as shown in FIG.
本发明实施例中仅仅以 G/E-PON和 10G-PON为例进行说明， 但不限于 此， 随着网络的演进， 网络中可能会出现单通道的 40G-PON、 100G-PON, 也都可以采用本发明的技术方案， 实现多种协议、 多种速率的 ONU共存， 在 此不再赘述。 In the embodiment of the present invention, only G/E-PON and 10G-PON are taken as an example, but the invention is not limited thereto. As the network evolves, a single channel 40G-PON and 100G-PON may appear in the network. The technical solution of the present invention can also be used to implement coexistence of ONUs of multiple protocols and multiple rates, and details are not described herein again.
本领域普通技术人员将会理解， 本发明的各个方面、 或各个方面的可能 实现方式可以被具体实施为***、 方法或者计算机程序产品。 因此， 本发明 的各方面、 或各个方面的可能实现方式可以采用完全硬件实施例、 完全软件 实施例 （包括固件、 驻留软件等等：)， 或者组合软件和硬件方面的实施例的形 式， 在这里都统称为"电路"、 "模块 "或者 "***"。 比如， 相应的处理单元， 可 以是相应的处理器， 或者是现场可编程整列 FPGA , 或者可以是集成电路 ASIC, 或者是处理器与存储器的结合， 或者是相应的集成芯片。 在本发明实 施例中， 相应的发送或接收单元可以是光发送器或光接收器， 或者结合有光 发送或光接收功能的光收发器。 此外， 本发明的各方面、 或各个方面的可能 实现方式可以采用计算机程序产品的形式， 计算机程序产品是指存储在计算 机可读介质中的计算机可读程序代码。  Those of ordinary skill in the art will appreciate that various aspects of the present invention, or possible implementations of various aspects, can be embodied as a system, method, or computer program product. Thus, aspects of the invention, or possible implementations of various aspects, may take the form of an entirely hardware embodiment, an entirely software embodiment (including firmware, resident software, etc.), or a combination of software and hardware aspects, They are collectively referred to herein as "circuits," "modules," or "systems." For example, the corresponding processing unit may be a corresponding processor, or a field programmable integer column FPGA, or may be an integrated circuit ASIC, or a combination of a processor and a memory, or a corresponding integrated chip. In the embodiment of the present invention, the corresponding transmitting or receiving unit may be an optical transmitter or an optical receiver, or an optical transceiver incorporating a light transmitting or light receiving function. Furthermore, aspects of the invention, or possible implementations of various aspects, may take the form of a computer program product, which is a computer readable program code stored on a computer readable medium.
计算机可读介质可以是计算机可读信号介质或者计算机可读存储介质。 计算机可读存储介质包含但不限于电子、 磁性、 光学、 电磁、 红外或半导体 ***、 设备或者装置，或者前述的任意适当组合，如随机存取存储器 RAM：)、 只读存储器 （ROM：)、 可擦除可编程只读存储器 (EPROM或者快闪存储器：)、 光纤、 便携式只读存储器 (CD-ROM：)。  The computer readable medium can be a computer readable signal medium or a computer readable storage medium. The computer readable storage medium includes, but is not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, device, or device, or any suitable combination of the foregoing, such as random access memory RAM:), read only memory (ROM:), Erasable programmable read-only memory (EPROM or flash memory:), optical fiber, portable read-only memory (CD-ROM:).
计算机中的处理器读取存储在计算机可读介质中的计算机可读程序代 码， 使得处理器能够执行在流程图中每个歩骤、 或各歩骤的组合中规定的功 能动作； 生成实施在框图的每一块、或各块的组合中规定的功能动作的装置。  The processor in the computer reads the computer readable program code stored in the computer readable medium, such that the processor can perform the functional actions specified in each of the steps, or combinations of steps in the flowchart; A device for functional operation specified in each block of the block diagram or in a combination of blocks.
计算机可读程序代码可以完全在用户的计算机上执行、 部分在用户的计 算机上执行、 作为单独的软件包、 部分在用户的计算机上并且部分在远程计 算机上， 或者完全在远程计算机或者服务器上执行。 也应该注意， 在某些替 代实施方案中， 在流程图中各歩骤、 或框图中各块所注明的功能可能不按图 中注明的顺序发生。 例如， 依赖于所涉及的功能， 接连示出的两个歩骤、 或 两个块实际上可能被大致同时执行， 或者这些块有时候可能被以相反顺序执 行。  The computer readable program code can be executed entirely on the user's computer, partly on the user's computer, as a separate software package, partly on the user's computer and partly on the remote computer, or entirely on the remote computer or server. . It should also be noted that in some alternative implementations, the functions noted in the various blocks of the flowchart, or in the block diagrams, may not occur in the order noted. For example, depending on the functionality involved, two steps, or two blocks, shown in succession may actually be performed substantially concurrently, or the blocks may sometimes be executed in the reverse order.
本领域普通技术人员可以意识到， 结合本文中所公开的实施例描述的各 示例的单元及算法歩骤， 能够以电子硬件、 或者计算机软件和电子硬件的结 合来实现。 这些功能究竟以硬件还是软件方式来执行， 取决于技术方案的特 定应用和设计约束条件。 专业技术人员可以对每个特定的应用来使用不同方 法来实现所描述的功能， 但是这种实现不应认为超出本发明的范围。 Those skilled in the art will appreciate that the elements and algorithms of the various examples described in connection with the embodiments disclosed herein can be implemented in electronic hardware, or in computer software and electronic hardware. Come together to achieve. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the solution. A person skilled in the art can use different methods to implement the described functions for each particular application, but such implementation should not be considered to be beyond the scope of the present invention.
最后应说明的是： 以上各实施例仅用以说明本发明的技术方案， 而非对 其限制； 尽管参照前述各实施例对本发明进行了详细的说明， 本领域的普通 技术人员应当理解：其依然可以对前述各实施例所记载的技术方案进行修改， 或者对其中部分或者全部技术特征进行等同替换。 因此， 本发明的保护范围 应以权利要求的保护范围为准。  Finally, it should be noted that the above embodiments are only for explaining the technical solutions of the present invention, and are not intended to be limiting thereof; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art will understand that The technical solutions described in the foregoing embodiments may be modified, or some or all of the technical features may be equivalently replaced. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

权 利 要 求 书 Claim
1、 一种波长切换方法， 其特征在于， 包括： A wavelength switching method, comprising:
光线路终端 OLT向光网络单元 ONU发送波长切换命令， 所述波长切换 命令用于指示所述 ONU从源波长通道切换到目的波长通道，其中，所述波长 切换命令携带开始时刻 t0， 所述 t0用于指示所述 ONU在 t0时刻开始从所述 源波长通道切换到所述目的波长通道；  The optical line terminal OLT sends a wavelength switching command to the optical network unit ONU, where the wavelength switching command is used to instruct the ONU to switch from the source wavelength channel to the destination wavelength channel, where the wavelength switching command carries a start time t0, the t0 Used to indicate that the ONU starts to switch from the source wavelength channel to the destination wavelength channel at time t0;
所述 OLT从所述 t0时刻起经过时间 T的时刻， 开始通过所述目的波长 通道向所述 ONU发送下行数据， 其中， 所述时间 T为所述 ONU从所述源波 长通道切换到所述目的波长通道所需时间。  The OLT starts to send downlink data to the ONU through the destination wavelength channel, and the time T is that the ONU switches from the source wavelength channel to the The time required for the destination wavelength channel.
2、根据权利要求 1所述的方法， 其特征在于， 所述 OLT向 ONU发送所 述波长切换命令之前， 还包括：  The method according to claim 1, wherein before the OLT sends the wavelength switching command to the ONU, the method further includes:
所述 OLT获取所述 ONU上报的所述时间 T。  The OLT acquires the time T reported by the ONU.
3、 根据权利要求 1或 2所述的方法， 其特征在于， 所述波长切换命令携 带所述目的波长通道的标识；  The method according to claim 1 or 2, wherein the wavelength switching command carries an identifier of the destination wavelength channel;
或携带所述目的波长通道的上行波长和 /或下行波长。  Or carrying the upstream wavelength and/or the downstream wavelength of the destination wavelength channel.
4、 根据权利要求 1〜3任一项所述的方法， 其特征在于， 所述波长切换 命令携带波长切换类型信息， 所述波长切换类型信息用于指示切换上行波长 和 /或下行波长。  The method according to any one of claims 1 to 3, wherein the wavelength switching command carries wavelength switching type information, and the wavelength switching type information is used to indicate switching uplink wavelengths and/or downlink wavelengths.
5、 根据权利要求 1〜4任一项所述的方法， 其特征在于， 所述方法还包 括：  The method according to any one of claims 1 to 4, wherein the method further comprises:
所述 OLT在本地存储器中存储所述下行数据；  The OLT stores the downlink data in a local storage;
所述 OLT在本地存储器中存储所述下行数据之后， 还包括：  After the OLT stores the downlink data in the local storage, the OLT further includes:
当所述 OLT在所述目的波长通道接收到所述 ONU发送的上行数据或波 长切换完成消息时， 所述 OLT释放所述本地存储器中存储的下行数据。  And when the OLT receives the uplink data or the wavelength switch completion message sent by the ONU in the destination wavelength channel, the OLT releases the downlink data stored in the local memory.
6、 根据权利要求 4所述的方法， 其特征在于， 所述方法还包括： 如果所述 OLT在预设的波长切换定时时间后，未在所述目的波长通道接 收到所述 ONU发送的上行数据或波长切换完成消息，所述 OLT在所述 ONU 回落到所述源波长通道后，在所述源波长通道向所述 ONU发送所述本地存储 器中存储的所述下行数据， 或者所述 OLT在所述 ONU重新注册后， 在所述 ONU重新注册的波长通道上重新向所述 ONU发送所述本地存储器中存储的 所述下行数据。 The method according to claim 4, wherein the method further comprises: if the OLT does not receive the uplink sent by the ONU in the destination wavelength channel after the preset wavelength switching timing time Data or wavelength switching completion message, after the ONU falls back to the source wavelength channel, the OLT sends the downlink data stored in the local memory to the ONU in the source wavelength channel, or the OLT After the ONU is re-registered, the ONU is re-registered on the wavelength channel that is re-registered by the ONU, and the local storage is stored in the local memory. The downlink data.
7、 根据权利要求 1〜6任一项所述的方法， 其特征在于， 所述 OLT 向 ONU发送波长切换命令之后， 还包括：  The method according to any one of claims 1 to 6, wherein after the OLT sends a wavelength switching command to the ONU, the method further includes:
所述 OLT从所述 t0时刻起经过所述时间 T的时刻， 开始通过所述目的 波长通道向所述 ONU发送上行时隙授权。  The OLT starts to send an uplink time slot grant to the ONU through the destination wavelength channel from the time T0 at the time t0.
8、 一种波长切换方法， 其特征在于， 包括：  8. A wavelength switching method, comprising:
光网络单元 ONU向光线路终端 OLT发送波长切换时间消息， 所述波长 切换时间消息携带时间 T ,所述时间 T为所述 ONU从源波长通道切换到目的 波长通道所需时间， 所述 T用于指示所述 OLT的等待时间， 所述等待时间是 指从所述 ONU开始波长切换到所述 OLT开始下发下行数据之间的等待时间 ·' 所述 ONU接收所述 OLT发送的所述波长切换命令， 所述波长切换命令 用于指示所述 ONU从源波长通道切换到目的波长通道，其中，所述波长切换 命令携带开始时刻 t0， 所述 t0用于指示所述 ONU在 t0时刻开始从所述源波 长通道切换到所述目的波长通道；  The optical network unit ONU sends a wavelength switching time message to the optical line terminal OLT, where the wavelength switching time message carries a time T, where the time T is the time required for the ONU to switch from the source wavelength channel to the destination wavelength channel, and the T is used. The waiting time for indicating the OLT, the waiting time refers to a waiting time between the wavelength switching from the ONU and the downlink data sent by the OLT, and the ONU receives the wavelength sent by the OLT. a switching command, the wavelength switching command is used to instruct the ONU to switch from the source wavelength channel to the destination wavelength channel, where the wavelength switching command carries a start time t0, where the t0 is used to indicate that the ONU starts at time t0. Switching the source wavelength channel to the target wavelength channel;
所述 ONU在所述 t0时刻开始从所述源波长通道切换到所述目的波长通 道；  The ONU starts to switch from the source wavelength channel to the destination wavelength channel at the time t0;
所述 ONU在切换到所述目的波长通道后，通过所述目的波长通道接收所 述 OLT发送的下行数据。  After switching to the destination wavelength channel, the ONU receives downlink data sent by the OLT through the destination wavelength channel.
9、 根据权利要求 8所述的方法， 其特征在于， 所述波长切换命令携带所 述目的波长通道的标识；  The method according to claim 8, wherein the wavelength switching command carries an identifier of the destination wavelength channel;
或携带所述目的波长通道的上行波长和 /或下行波长。  Or carrying the upstream wavelength and/or the downstream wavelength of the destination wavelength channel.
10、 根据权利要求 8或 9所述的方法， 其特征在于， 所述波长切换命令 还携带波长切换类型信息， 所述波长切换类型信息包括切换上行波长和 /或下 行波长的指示信息。  The method according to claim 8 or 9, wherein the wavelength switching command further carries wavelength switching type information, and the wavelength switching type information includes indication information for switching an uplink wavelength and/or a downlink wavelength.
11、 一种用于波长切换的装置， 其特征在于， 包括：  11. A device for wavelength switching, comprising:
处理单元，用于生成波长切换命令， 并指示向光网络单元 ONU发送所述 波长切换命令，所述波长切换命令用于指示所述 ONU从源波长通道切换到目 的波长通道， 其中， 所述波长切换命令携带开始时刻 to , 所述 to用于指示所 述 ONU在 t0时刻开始从所述源波长通道切换到所述目的波长通道； 还用于 指示在从所述 t0时刻起经过时间 T的时刻， 开始通过所述目的波长通道向所 述 ONU发送下行数据。 a processing unit, configured to generate a wavelength switching command, and instruct the optical network unit ONU to send the wavelength switching command, where the wavelength switching command is used to instruct the ONU to switch from a source wavelength channel to a destination wavelength channel, where the wavelength is The switching command carries a start time to, the to is used to indicate that the ONU starts to switch from the source wavelength channel to the destination wavelength channel at time t0; and is further configured to indicate a time elapsed from the time t0 Starting to pass through the target wavelength channel The ONU sends downlink data.
12、 根据权利要求 11所述的用于波长切换的装置， 其特征在于， 所述装 置还包括：  The device for wavelength switching according to claim 11, wherein the device further comprises:
发送单元，用于根据处理单元的指示向所述 ONU发送波长切换命令；从 所述 t0时刻起， 经过时间 T, 通过所述目的波长通道向所述 ONU发送下行 数据， 其中， 所述时间 T为所述 ONU从所述源波长通道切换到所述目的波 长通道所需时间。  a sending unit, configured to send a wavelength switching command to the ONU according to the instruction of the processing unit; and send, by using the time T, a downlink data to the ONU by using the destination wavelength channel, where the time T is The time required for the ONU to switch from the source wavelength channel to the destination wavelength channel.
13、 根据权利要求 12所述的用于波长切换的装置， 其特征在于， 所述装 置还包括：  The device for wavelength switching according to claim 12, wherein the device further comprises:
接收单元， 用于获取所述 ONU上报的所述时间  a receiving unit, configured to acquire the time reported by the ONU
14、 根据权利要求 12或 13所述的用于波长切换的装置， 其特征在于， 所述波长切换命令携带所述目的波长通道的标识；  The device for wavelength switching according to claim 12 or 13, wherein the wavelength switching command carries an identifier of the destination wavelength channel;
或携带所述目的波长通道的上行波长和 /或下行波长。  Or carrying the upstream wavelength and/or the downstream wavelength of the destination wavelength channel.
15、根据权利要求 12〜14任一项所述的用于波长切换的装置， 其特征在 于， 所述波长切换命令还携带波长切换类型信息， 所述波长切换类型信息用 于指示切换上行波长和 /或下行波长。  The device for wavelength switching according to any one of claims 12 to 14, wherein the wavelength switching command further carries wavelength switching type information, where the wavelength switching type information is used to indicate switching uplink wavelengths and / or downstream wavelength.
16、根据权利要求 12〜15任一项所述的用于波长切换的装置， 其特征在 于， 还包括： 存储单元， 用于在本地存储器中存储所述下行数据。  The device for wavelength switching according to any one of claims 12 to 15, further comprising: a storage unit, configured to store the downlink data in a local memory.
17、根据权利要求 16所述的用于波长切换的装置，其特征在于，还包括： 处理单元，用于当光线路终端 OLT在所述目的波长通道接收到所述 ONU 发送的上行数据或波长切换完成消息时， 释放所述本地存储器中存储的下行 数据。  The device for wavelength switching according to claim 16, further comprising: a processing unit, configured to: when the optical line terminal OLT receives the uplink data or the wavelength sent by the ONU in the destination wavelength channel When the completion message is switched, the downlink data stored in the local storage is released.
18、 根据权利要求 16或 17所述的用于波长切换的装置， 其特征在于， 所述发送单元，还用于当所述 OLT在预设的波长切换定时时间后未在所述目 的波长通道接收到所述 ONU发送的上行数据或波长切换完成消息时，在所述 ONU回落到所述源波长通道后， 在所述源波长通道向所述 ONU发送所述本 地存储器中存储的所述下行数据，或者在所述 ONU重新注册后，在所述 ONU 重新注册的波长通道上重新向所述 ONU发送所述本地存储器中存储的所述 下行数据。  The device for wavelength switching according to claim 16 or 17, wherein the transmitting unit is further configured to: when the OLT is not in the destination wavelength channel after a preset wavelength switching timing time Receiving the uplink data or the wavelength switch completion message sent by the ONU, after the ONU falls back to the source wavelength channel, sending the downlink stored in the local memory to the ONU in the source wavelength channel. Data, or after the ONU re-registers, retransmits the downlink data stored in the local memory to the ONU on the wavelength channel re-registered by the ONU.
19、根据权利要求 12〜18任一项所述的用于波长切换的装置， 其特征在 于， 所述发送单元， 还用于从所述 to时刻起， 经过所述时间 T, 通过所述目 的波长通道向所述 ONU发送上行时隙授权。 19. Apparatus for wavelength switching according to any one of claims 12 to 18, characterized in that The sending unit is further configured to send, by using the time T, the uplink time slot authorization to the ONU through the destination wavelength channel from the to time.
20、 一种用于波长切换的装置， 其特征在于， 包括：  20. A device for wavelength switching, comprising:
发送单元， 用于向光线路终端 OLT发送波长切换时间消息， 所述波长切 换时间消息携带时间 T,所述时间 T为光网络单元 ONU从源波长通道切换到 目的波长通道所需时间， 所述 T用于指示所述 OLT的等待时间， 所述等待时 间是指从所述 ONU开始波长切换到所述 OLT开始下发下行数据之间的等待 时间；  a sending unit, configured to send a wavelength switching time message to the optical line terminal OLT, where the wavelength switching time message carries a time T, where the time T is a time required for the optical network unit ONU to switch from the source wavelength channel to the destination wavelength channel, The T is used to indicate the waiting time of the OLT, where the waiting time refers to a waiting time between the wavelength switching from the ONU and the downlink data sent by the OLT.
接收单元， 用于接收光线路终端 OLT发送的波长切换命令， 所述波长切 换命令用于指示所述 ONU从源波长通道切换到目的波长通道，其中，所述波 长切换命令携带开始时刻 t0， 用于指示所述 ONU在 t0时刻开始从所述源波 长通道切换到所述目的波长通道；  a receiving unit, configured to receive a wavelength switching command sent by the optical line terminal OLT, where the wavelength switching command is used to instruct the ONU to switch from a source wavelength channel to a destination wavelength channel, where the wavelength switching command carries a starting time t0, Instructing the ONU to start switching from the source wavelength channel to the destination wavelength channel at time t0;
处理单元， 用于在所述 to时刻， 从所述源波长通道切换到所述目的波长 通道；  a processing unit, configured to switch from the source wavelength channel to the destination wavelength channel at the time of to;
所述接收单元， 还用于在切换到所述目的波长通道后， 通过所述目的波 长通道接收所述 OLT发送的下行数据。  The receiving unit is further configured to: after switching to the destination wavelength channel, receive downlink data sent by the OLT through the destination wavelength channel.
21、 根据权利要求 20所述的用于波长切换的装置， 其特征在于， 所述波 长切换命令携带所述目的波长通道的标识；  The device for wavelength switching according to claim 20, wherein the wavelength switching command carries an identifier of the destination wavelength channel;
或携带所述目的波长通道的上行波长和 /或下行波长。  Or carrying the upstream wavelength and/or the downstream wavelength of the destination wavelength channel.
22、 根据权利要求 20或 21所述的用于波长切换的装置， 其特征在于， 所述波长切换命令还携带波长切换类型信息， 所述波长切换类型信息包括切 换上行波长和 /或下行波长的指示信息。  The device for wavelength switching according to claim 20 or 21, wherein the wavelength switching command further carries wavelength switching type information, and the wavelength switching type information includes switching uplink wavelength and/or downlink wavelength. Instructions.
23、 一种无源光网络***， 包括光线路终端 OLT和光网络单元 ONU, 所述 OLT通过光分配网络 ODN连接至少一个所述 ONU, 其特征在于， 所述 OLT包括如权利要求 11〜19任一项所述的 OLT,所述 ONU包括如权利要求 20〜22任一项所述的 ONU。  A passive optical network system, comprising an optical line terminal OLT and an optical network unit ONU, wherein the OLT connects at least one of the ONUs through an optical distribution network ODN, wherein the OLT comprises any one of claims 11 to 19 An OLT, the ONU comprising the ONU of any one of claims 20-22.
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CN103475439A (en) * 2013-09-06 2013-12-25 南京邮电大学 Channel wavelength selection method based on TDM/WDM mixed PON structure

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