CN102648590B - Communication means, system and the device of optical network system - Google Patents

Abstract

The embodiment of the present invention discloses a method, system and device for data communication in an optical network system. After the communication between the main terminal and multiple optical network units is switched from the first optical line terminal port to the second optical line terminal port, through The second optical line terminal port sends a downlink frame to at least one optical network unit, and the downlink frame instructs the at least one optical network unit to use the first preamble to send an uplink frame, or sends a deactivation message or sends a message carrying reallocation The message of the optical network unit identification is sent to at least one optical network unit. The present invention realizes that the optical network system can perform re-ranging even if the POPUP message is not supported after the switchover, and then quickly recovers the data communication between the OLT and the ONU after the switchover, avoiding This reduces the impact on normal business communications after handover, reduces handover delay, and improves user satisfaction.

Description

Communication method, system and device of optical network system

technical field

The present invention relates to the technical field of communication, in particular to a communication method, system and device of an optical network system.

Background technique

A passive optical network (Passive Optical Network, PON) technology is currently one of the most widely used fiber-to-the-home (Fiber To The Home, FTTH) technologies. Existing PONs include Broadband Passive Optical Network (BPON), Gigabit-capable Passive Optical Network (GPON), Ethernet Passive Optical Network (Ethernet Passive Optical Network, EPON), and 10 Gigabit Passive Optical Network (10 Gigabit-capable Passive Optical Networks, XG-PON).

The traditional PON system mainly includes: optical line terminal (OpticalLineTerminal, OLT), optical network unit (OpticalNetworkUnit, ONU) and optical distribution network (OpticalDistributionNetwork, ODN) and other parts, wherein, the optical distribution network includes backbone optical fiber, passive optical splitter and branch fibers. The OLT and the passive optical splitter are connected through the main optical fiber, and the optical splitter realizes point-to-multipoint optical power distribution, and is connected to multiple ONUs through multiple branch optical fibers. Wherein, the direction from the OLT to the ONU is called the downlink direction, and the direction from the ONU to the OLT is called the uplink direction.

The upstream direction of the PON system usually adopts Time Division Multiple Access (TimeDivisionMultipleAddress, TDMA) multiplexing mode, and each ONU sends the upstream data message in the time slot specified by the OLT; and the downstream direction OLT adopts Time Division Multiplexing (TimeDivisionMultiplexing, TDM) The ONU sends the downlink data message, and the optical signal carrying the downlink data message of all ONUs is divided into several parts at the optical splitter of the ODN, and reaches each ONU through each branch optical fiber.

Among them, in the GPON system, when the optical fiber between the active OLT and the ONU fails, the OLT and the ONU will detect a LOS (lost of signal, loss of signal) alarm because they cannot receive the signal from the other party; the active OLT detects a LOS alarm , indicating that the main trunk fiber is faulty, and a master-standby OLT switchover is required, and all ONUs are switched to the standby OLT, and the original standby OLT is switched to become the active OLT. After the ONU detects the LOS alarm, it switches from the normal OPERATION state to the POPUP state, and stops sending uplink data; the master OLT broadcasts a POPUP message to all ONUs, notifies the ONUs to change from the POPUP state to the RANGING state, and starts re-ranging of all ONUs Processing: Under the control of the active OLT, the ranging processing of all ONUs is completed in a serial manner, and the data communication between the OLT and the ONU is restored.

In the process of realizing the present invention, the inventor finds that there are at least the following problems in the prior art:

When the optical fiber between the active OLT and the ONU fails, after the active and standby backbone optical fibers are switched, each ONU needs to be re-measured. Since the XGPON system or other optical network systems do not support POPUP messages, the ONU cannot enter the re-ranging state, and then This makes it impossible for the ONU to obtain an accurate equalization delay, resulting in interruption of communication between the OLT and the ONU after the active/standby switchover.

Contents of the invention

The purpose of the embodiments of the present invention is to provide a communication method, system and device of an optical network system, which is used to solve the problem of communication between the OLT and the ONU after the OLT performs active-standby switchover in the existing optical network system because it does not support POPUP messages. The problem of data communication interruption can be avoided, thereby avoiding the impact on normal business communication after switching, and improving user satisfaction.

In order to solve the above problems, an embodiment of the present invention provides a communication method for an optical network system. The central office of the optical network system provides a first optical line terminal port and a second optical line terminal port, and each optical line terminal port is connected to A plurality of optical network units, the method comprising:

After the communication between the main terminal and the multiple optical network units is switched from the first optical line terminal port to the second optical line terminal port, a downlink frame is sent to at least one optical network unit through the second optical line terminal port, and the downlink frame is instructing the at least one optical network unit to use a first preamble to send an uplink frame, wherein the length of the first preamble is greater than the length of a second preamble used for uplink traffic transmission;

Detecting an uplink frame containing a first preamble sent by the at least one optical network unit through the second optical line terminal port, and obtaining an equalized delay of the at least one optical network unit based on the uplink frame containing the first preamble ;

Send the equalized delay to the at least one optical network unit through the second optical line terminal port, so that the at least one optical network unit communicates with the second optical line terminal port based on the equalized delay. communication.

The embodiment of the present invention also provides another communication method for an optical network system, the method comprising:

Based on the first equalization delay and communicating with the first optical line terminal port, to perform service transmission;

Switching from the first optical line terminal port to the second optical line terminal port, receiving a downlink frame from the second optical line terminal port, the downlink frame indicating that the uplink frame adopts a first preamble, wherein the length of the first preamble is greater than that used The length of the second preamble for uplink service transmission;

sending an uplink frame including the first preamble to a second optical line terminal port;

receiving a second equalization delay from a second optical line terminal port;

Based on the second equalization delay, communicate with the second optical line terminal port to perform service transmission.

The present invention also provides another communication method for an optical network system. The central office of the optical network system provides a first optical line terminal port and a second optical line terminal port, and each optical line terminal port is connected to a plurality of optical network units. The methods include:

After the communication between the main terminal and multiple optical network units is switched from the first optical line terminal port to the second optical line terminal port, a deactivation message is sent through the second optical line terminal port or a message carrying a reallocated optical network unit identifier is sent. Send a message to at least one optical network unit, so that the at least one optical network unit goes offline;

Re-ranging the at least one optical network unit to obtain a first equalization delay of the at least one optical network unit;

Send the equalized delay to the at least one optical network unit through the second optical line terminal port, so that the at least one optical network unit communicates with the second optical line terminal port based on the equalized delay. communication.

The embodiment of the present invention also provides a communication method for an optical network system, the method comprising:

Based on the first equalization delay and communicating with the first optical line terminal port, to perform service transmission;

Switching from the first OLT port to the second OLT port, receiving a deactivation message from the second OLT port or a message carrying a reallocated ONU identifier;

Go offline according to the deactivation message;

After re-ranging, receive the second equalization delay from the second optical line terminal port;

Based on the second equalization delay, communicate with the second optical line terminal port to perform service transmission. An embodiment of the present invention provides an optical network system. The system includes: a first optical line terminal port and a second optical line terminal port, and the optical line terminal is connected to a plurality of optical network units through each optical line terminal port;

The optical line terminal is configured to, after the communication between the optical line terminal and a plurality of optical network units is switched from the first optical line terminal port to the second optical line terminal port, send at least one optical line terminal through the second optical line terminal port The network unit sends a downlink frame, and the downlink frame instructs the at least one optical network unit to use a first preamble to send an uplink frame, wherein the length of the first preamble is greater than the length of a second preamble used for uplink service transmission; detecting the At least one optical network unit sends an uplink frame containing the first preamble through the second optical line terminal port, and based on the uplink frame containing the first preamble, obtain the equalization delay of the at least one optical network unit; through the The second OLT port sends the equalized time delay to the at least one ONU, so that the at least one ONU communicates with the second OLT port based on the equalized time delay.

The at least one optical network unit is used to communicate with the first optical line terminal port based on the first equalization delay to perform service transmission; switch from the first optical line terminal port to the second optical line terminal port, and receive information from the second optical line terminal port The downlink frame of the optical line terminal port, the downlink frame indicates that the uplink frame adopts the first preamble, wherein the length of the first preamble is greater than the length of the second preamble used for uplink service transmission; sending to the second optical line terminal port includes The first leading uplink frame; receiving a second equalization delay from the second optical line terminal port; communicating with the second optical line terminal port based on the second equalization delay to perform service transmission.

The embodiment of the present invention also provides another optical network system. The system includes: a first optical line terminal port and a second optical line terminal port, and the optical line terminal is connected to a plurality of optical network units through each optical line terminal port;

The optical line terminal is configured to send a deactivation message through the second optical line terminal port after the communication between the optical line terminal and a plurality of optical network units is switched from the first optical line terminal port to the second optical line terminal port Or send a message carrying a redistributed ONU identifier to at least one ONU, so that the at least one ONU goes offline; re-range the at least one ONU to obtain the at least one ONU The first equalization delay of the unit; sending the equalization delay to the at least one optical network unit through the second optical line terminal port, so that the at least one optical network unit is based on the equalization delay and the communicating through the second optical line terminal port;

The optical network unit is configured to communicate with the first optical line terminal port based on the first equalization delay to perform service transmission; switch from the first optical line terminal port to the second optical line terminal port, and receive information from the second optical line terminal port The deactivation message of the terminal port or the message carrying the redistributed optical network unit identification; according to the deactivation message, go offline;

After re-ranging, receive a second equalization delay from the second optical line terminal port; communicate with the second optical line terminal port based on the second equalization delay to perform service transmission.

An embodiment of the present invention provides an optical line terminal, and the optical line terminal includes:

The first sending unit is configured to, when the communication between the optical line terminal and multiple optical network units is switched from the first optical line terminal port to the second optical line terminal port, send the communication to at least one of the optical line terminal ports through the second optical line terminal port The optical network unit sends a downlink frame, and the downlink frame instructs the at least one optical network unit to use a first preamble to send an uplink frame, wherein the length of the first preamble is greater than the length of the second preamble used for uplink traffic transmission;

The first acquisition unit is configured to detect the uplink frame containing the first preamble sent by the at least one optical network unit through the second optical line terminal port; based on the uplink frame containing the first preamble, obtain the at least one The equalization delay of the optical network unit;

The second sending unit is configured to send the equalization delay of the at least one optical network unit to the at least one optical network unit through the second optical line terminal port, so that the at least one optical network unit is based on the The equalization delay communicates with the second optical line terminal port.

The embodiment of the present invention also provides an optical network unit, and the optical network unit includes:

The receiving unit is configured to communicate with the first optical line terminal port based on the first equalization delay to perform service transmission; switch from the first optical line terminal port to the second optical line terminal port, and receive the signal from the second optical line terminal port A downlink frame, where the downlink frame indicates that the uplink frame adopts a first preamble, wherein the length of the first preamble is greater than the length of the second preamble used for uplink service transmission;

a fifth sending unit, configured to send the uplink frame including the first preamble to the second optical line terminal port;

The second receiving unit is configured to receive the second equalized delay from the second optical line terminal port; communicate with the second optical line terminal port based on the second equalized delay to perform service transmission.

The embodiment of the present invention also provides an optical line terminal, where the optical line terminal includes:

The third sending unit is configured to send deactivation through the second optical line terminal port after the communication between the optical line terminal and multiple optical network units is switched from the first optical line terminal port to the second optical line terminal port message or send a message carrying the reallocated ONU identifier to at least one ONU, so that the at least one ONU goes offline;

The fourth obtaining unit is configured to re-range the at least one optical network unit, and obtain the first equalization delay of the at least one optical network unit;

A fourth sending unit, configured to send the equalized time delay to the at least one optical network unit through the second optical line terminal port, so that the at least one optical network unit is based on the equalized time delay and the The second optical line termination port communicates.

In the method, system and device for data communication in an optical network system provided by the embodiments of the present invention, after the communication between the main terminal and multiple optical network units is switched from the first optical line terminal port to the second optical line terminal port, through the The second optical line terminal port sends a downlink frame to at least one optical network unit, the downlink frame instructs the at least one optical network unit to use the first preamble to send an uplink frame, or sends a deactivation message or sends an optical network unit carrying reallocation The message of the network unit identification is sent to at least one optical network unit, so that the optical network system can re-range the state even if it does not support the POPUP message after the switchover, and then quickly restore the data communication between the OLT and the ONU after the switchover, avoiding the post-switchover The impact on normal business communication reduces handover delay and improves user satisfaction.

Description of drawings

In order to illustrate the technical solutions of the embodiments of the present invention more clearly, the following briefly introduces the drawings that need to be used in the description of the embodiments. Apparently, the drawings in the following description are only some embodiments of the present invention, and those skilled in the art can obtain other drawings according to these drawings without creative efforts.

FIG. 1 is a flowchart of a data communication method of an optical network system provided by an embodiment of the present invention;

FIG. 2 is a schematic diagram of the state of an optical network unit provided by an embodiment of the present invention;

FIG. 3 is a specific method flowchart of a data communication method for an optical network system provided by an embodiment of the present invention;

FIG. 4 is a schematic structural diagram of a downlink XGTC frame provided by an embodiment of the present invention;

FIG. 5 is a schematic diagram of a BWMAP structure in a downlink XGTC frame structure provided by an embodiment of the present invention;

FIG. 6 is a flow chart of another optical network system data communication method provided by an embodiment of the present invention;

FIG. 7 is a schematic structural diagram of an optical network system provided by an embodiment of the present invention;

FIG. 8 is a schematic structural diagram of an optical line terminal provided by an embodiment of the present invention;

FIG. 9 is a schematic structural diagram of an optical network unit provided by an embodiment of the present invention;

Fig. 10 is a schematic structural diagram of another optical line terminal provided by an embodiment of the present invention.

detailed description

The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the drawings in the embodiments of the present invention. Apparently, the described embodiments are only some of the embodiments of the present invention, but not all of them. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention.

FIG. 1 is a flowchart of a data communication method of a passive optical network system provided by an embodiment of the present invention. As shown in Figure 1, the method of the embodiment of the present invention may include the following steps:

The central office of the optical network system provides a first OLT port and a second OLT port, and each OLT port is connected to a plurality of ONUs, and the method includes:

Step S102, after the communication between the authority end and multiple ONUs is switched from the first OLT port to the second OLT port, a downlink frame is sent to at least one ONU through the second OLT port, and the downlink frame indicates the at least one optical network The unit uses the first preamble to send the uplink frame, wherein the length of the first preamble is greater than the length of the second preamble used for uplink service transmission.

Further, the optical network system may be a 10 gigabit passive optical network XG-PON system (or XGPON for short), and the XGPON system includes: XGPON1 system and XGPON2 system, these two systems are next-generation gigabit Two main candidate architectures of bit passive optical network NGPON1 (also called "next generation gigabit passive optical network"). XGPON1 is an asymmetric system with 10Gbps downlink/2.5Gbps uplink; XGPON2 is a symmetric system with 10Gbps uplink and downlink. The XGPON1 system is an asymmetrical system, which can also be called 10GGPON; the central office is a network side device, which is relative to a user end device, such as an OLT. The embodiment of the present invention only uses the ONU as an example for description, and all methods applicable to the ONU are also applicable to the ONT.

Further, the downlink frame may be an XGTC frame. The uplink burst (frame) template BurstProfile field in the downlink frame is set to the first preamble, which can also be called a long preamble (also can be called a long frame header), and the BurstProfile field in the downlink frame includes the first preamble and The second preamble (which may be called a short preamble or a short frame header), wherein the length of the first preamble is greater than the length of the second preamble used for uplink traffic transmission, and this field is used to indicate which Uplink frame of preamblebytes. Wherein, the BurstProfile field is located in the frame header of the downlink frame; the first preamble is the preamble used when the ONU enters the ranging state, that is, the O4 state; the second preamble is the preamble used when the ONU is in the running state, that is, the O5 state .

Further, before sending the downlink frame, the OLT also includes: generating an uplink bandwidth authorization message, the authorization message includes bandwidth information indicating the uplink frame and preamble template information, and the preamble template information indicates that the at least one optical network unit adopts the first Sending an uplink frame as a preamble; encapsulating an uplink bandwidth authorization message into the downlink frame.

Step S104, the OLT detects the uplink frame containing the first preamble sent by the at least one ONU through the second OLT port.

Step S106, the OLT obtains the equalization delay of the at least one optical network unit based on the uplink frame including the first preamble.

Step S108, the OLT sends the equalization delay to the at least one optical network unit through the second optical line terminal port, so that the at least one optical network unit is based on the equalization delay and the first Two optical line terminal ports for communication.

Further, the method further includes: the OLT obtains the balanced delay of other optical network units in the plurality of optical network units based on the balanced delay sent by the second optical line terminal port; The equalization delay of the network unit is sent to the corresponding other optical network unit; or,

The OLT obtains the equalized delay offset of the at least one optical network unit based on the equalized delay sent by the second optical line terminal port, and sends the equalized time shift offset to the plurality of optical network units other optical network units.

Wherein, the OLT obtains the balanced delay offset of the at least one optical network unit, and sending the balanced time shift offset to other optical network units in the plurality of optical network units specifically includes two ways:

One is, after the OLT sends the first equalization time delay EqD1 to the at least one ONU through the first sending port and the second equalization time delay EqD2 sent to the at least one ONU through the second sending port, Calculate the EqD offset of EqD1 and EqD2. At this time, the EqD offset can be estimated as the EqD offset of each ONU after switching from the first OLT port to the second OLT port. According to the EqD offset, other components in the optical network system can be calculated. EqD of each ONU, and deliver the EqD to each corresponding ONU in a unicast manner through the second OLT port.

The second is that after the OLT calculates the EqD deviation, it is broadcast to other ONUs in the optical network system through the second OLT port, and the other ONUs calculate the EqD after switching according to the EqD deviation, and then based on the described The switched EqD communicates with the OLT through the second OLT port.

Compared with the above-mentioned communication methods, for the ONU, the methods performed on the ONU side include:

The ONU communicates with the first optical line terminal port based on the first equalization delay to perform service transmission;

Switching from the first optical line terminal port to the second optical line terminal port, the ONU receives a downlink frame from the second optical line terminal port, and the downlink frame indicates that the uplink frame adopts a first preamble, wherein the length of the first preamble is greater than The length of the second preamble used for uplink service transmission;

The ONU sends the upstream frame including the first preamble to the second optical line terminal port;

The ONU receives the second equalization delay from the second optical line terminal port;

The ONU communicates with the second optical line terminal port based on the second equalization delay to perform service transmission.

The embodiment of the present invention provides a data communication method in an optical network system. After the communication between the main terminal and multiple optical network units is switched from the first optical line terminal port to the second optical line terminal port, the second optical line The line terminal port sends a downlink frame to at least one optical network unit, and the downlink frame instructs the at least one optical network unit to use a first preamble to send an uplink frame, wherein the length of the first preamble is longer than the second preamble used for uplink service transmission. The length of the preamble: detecting the uplink frame containing the first preamble sent by the at least one optical network unit through the second optical line terminal port, and obtaining the at least one optical network unit based on the uplink frame containing the first preamble the equalized delay; send the equalized delay to the at least one optical network unit through the second optical line terminal port, so that the at least one optical network unit is based on the equalized delay and the second The optical line terminal port communicates, so that the optical network system can re-range the state even if it does not support the POPUP message after the switchover, and then quickly restore the data communication between the OLT and the ONU after the switchover, avoiding the normal business communication after the switchover Influence, reduce switching delay, improve user satisfaction, especially for XGPON system, further solve the problem of TYPEB active/standby switching in XGPON system.

FIG. 2 is a schematic diagram of states of an optical network unit provided by an embodiment of the present invention, specifically a schematic diagram of various states of an optical network unit in an XGPON system. Taking the XPON system as an example, the communication method in the above optical network system will be described in detail by introducing various state diagrams of the ONU in the XPON system.

As shown in Figure 2, the state change of the ONU has 6 states:

(1) O1-Initial state

In the initial state, the optical transmission is turned off, and all configuration parameters of the transmission control TC layer include the ONU-ID. The default or explicit bandwidth allocation identifier Alloc-Id is the ONU identifier. When the ONU is synchronized with the downlink optical signal, it switches to the O2-3 state.

(2)O2-3-SerialNumberstate

Serial number SN state, the ONU activates the optical transmission function, receives and learns the Burst template (that is, the template of the upstream burst frame) PLOAM message, when the ONU receives the SN window opening message with the known Burst template, it sends a response physical message with the SN Layer operation management maintains the XGTC frame of PLOAM. At this time, ONU ignores the uplink dynamic bandwidth report DBRu identifier and bandwidth mapping authorization width BWMAPGrantSize area. When the ONU receives a PLOAM message with a serial number SN equal to its own SN to allocate an ONU-ID, the ONU enters the O4 state. When receiving a Disable_Serial_NumberPLOAM message whose SN is equal to its own SN, the ONU enters the O7 state. If the OLT has already known the existence of the ONU in some way, for example, in the process of power failure recovery, the OLT can directly pass an ONU-IDPLOAM message with a known ONUSN, so that the ONU can ignore the O2-3 state and directly enter O4 state.

(3)O4-Rangingstate

In the ranging state, if the ONU receives a ranging request with a known template, it responds with an XGTC frame with RegistrationPLOAM, and ignores the DBRu flag and the GrantSize area during ranging. The ONU in the O4 state responds with the following information: Profile (uplink burst frame profile), ranging time Ranging_Time, deactivated optical network identifier Deactivate_ONU-ID, and disabled serial number Disable_Serial_Number. When the timer TO1 expires, the ONU discards the ONU-ID, the default Alloc-ID and the default ONU management control interface XGPON encapsulation mode port ID OMCIXGEMport-ID, and enters the O2-3 state, retaining the upstream burst frame BurstFrame template information. When the ONU receives an equalization delay EqD message of an absolute value, it enters the O5 state. If the OLT has tested the round-trip delay RTD of the ONU during the SN confirmation or the early ONU activation process, the OLT can directly send a Ranging_Time message, so that the ONU can directly enter the O5 state through the O4 state. without going through the ranging process.

(4)O5-Operationstate

In the running state, the ONU is in the normal running state at this time, and performs data communication with the OLT.

(5) O6-Intermittent LODS state

Interrupt signal loss state, if the downlink signal loss LODS state recovers before timer TO2 expires, then return to O5 state, if there is no LODS recovery before TO2 expires, then enter O1 state.

(6) O7-Emergency Stopstate

In the emergency stop state, the ONU receives the disable serial number DisableSN message (the enable or disable field is configured as disabled), and the sending light is turned off. The configuration parameters of the transmission TC layer include: the optical network unit identifier ONU-ID, all The allocation identifier Alloc-ID, default XGEMPort-ID, burst template, and EqD are all discarded. In the O7 state, the ONU maintains downlink synchronization, parses downlink PLOAM messages, and prohibits downlink forwarding of data and uplink sending of data. After re-enabling, the OLT sends a disable serial number DisableSN message (the "enable or disable" field is configured as enable), and the ONU should enter the O1 state and go online again. When the ONU in O7 state restarts, the ONU should remain in O7 state.

Timer TO1Rangingtimer is the ranging timeout timer, which ensures that the ONU cannot stay in the ranging state for too long. The standard recommendation is 10 seconds. In the O5 state, the ranging state timeout timer will be stopped; Timer TO2

LODStimer is a Loss of Downstream Signal (LODS) overtime timer, which ensures that the ONU is not in the O6 state for too long, and the time of the O6 state suggested by the standard is 100ms.

In the following, in conjunction with the ONU state diagram of FIG. 2, the specific method flow of a data communication method for a passive optical network system provided by the embodiment of the present invention shown in FIG. 3 is introduced in detail. The method of the embodiment of the present invention may include the following steps :

Step S302, when the optical fiber between the OLT and the ONU fails, the OLT detects a signal loss LOS alarm, starts the switching process, the OLT switches from the first OLT port to the second OLT port, and switches all ONUs to the second OLT port.

Further, before switching, the first OLT port has no upstream optical signal, then the OLT judges to enter the TYPEB protection process, that is, performs active-standby switching, switches the first OLT port to the second OLT port, and then switches all ONUs to on the second OLT port.

Step S304, after the ONU detects the LODS alarm, the ONU switches from the normal OperationState to the IntermittentLODSState, and stops sending uplink data.

The ONU in this step can detect LODS for at least one ONU, and the ONU changes from the O5 state to the O6 state, and other ONUs also perform similar operations (see Figure 4).

Step S306 , the downlink of the second OLT port emits light (no bandwidth is allocated), all uplink bandwidth is closed, and after waiting for a period of time, the ONU enters from IntermittentLODSState to OperationState.

According to the ONU state diagram in Figure 2, when any ONU detects a LODS alarm, it enters the O6 state and starts the TO2 timer. In the O5 state, if the timer expires and has not been recovered, it will enter the O1 state.

Step S308, the OLT selects at least one ONU from the ONUs entering OperationState, and sends a downlink frame to the at least one ONU, and the downlink frame instructs the at least one optical network unit to use the first preamble to send the uplink frame, wherein the first The length of the first preamble is greater than the length of the second preamble used for uplink service transmission.

The ONU that re-enters the O5 state here can have multiple, also can be one, because the time that each ONU enters the O5 state is not the same, so as long as one ONU enters the O5 state, the OLT just can carry out step S208 to the ONU, certainly, The OLT may also select one or more ONUs entering the O5 state to perform step S208.

Specifically, after the OLT selects at least one ONU, it sets the BurstProfile field in the downlink frame as the first preamble, which is used to indicate that the selected ONU adopts the uplink frame using the first preamble. Wherein the BurstProfile field is in the frame header part of the downlink frame. Taking the XGTC frame in XGPON as an example, how to set the BurstProfile field as a long preamble is described in detail below, but the embodiment of the present invention is not limited to the XGPON system, and is applicable to passive Any type of optical network system.

The XGTC frame of the XG-PON is taken as an example below to describe the frame structure of the XGTC in detail, as shown in FIG. 4 , which is a schematic diagram of the frame structure of the downlink XGTC frame.

The downlink XGTC frame has 135432 bytes, including: XGTC frame header and XGTC payload payload. The XGTCheader includes: HLend, which is used to represent the number of BWmaps and the number of PLOAMs; bandwidth mapping BWmap and PLOAMd. The specific BWmap structure is shown in Figure 5.

Figure 5 is a schematic diagram of the structure of BWmap. BWmap includes: allocation structure AllocationStructure, the number of which allocation structure changes with the change of N, specifically includes: uplink burst (frame) template BurstProfile, 2 bits, used to indicate which ONU adopts The upstream frame of the preamble, or the upstream frame of which frame header is used to indicate the ONU (the upstream frame is the upstream burst frame here), the general BurstProfile includes: the first preamble (also called a long frame header or a long preamble) And the second preamble (also can be referred to as long frame header or long preamble and short frame header), wherein the first preamble is used for OLT registration discovery, is the preamble used when ONU enters ranging state namely O4 state; Its length is longer than the first The length of the second preamble (number of bytes Bite) is long, generally at least greater than or equal to 8 bits. The second preamble is used for the preamble used in normal communication or normal uplink service transmission, that is, the preamble used when the ONU is in the O5 state. The AllocationStructure also includes: allocation identifier Alloc-ID, 4 bits, used to identify the upstream bandwidth allocated by the OLT to the ONU; flag bit Flags, 2 bits; start time StartTime, 16 bits; bandwidth authorization length GrantSize, 16 bits; power management identifier FWI, 1 bit; error detection and correction code HEC of Hlend structure, 13 bits.

The specific use process is as follows:

For example, the ONU has recorded multiple burst (frame) templates BurstProfile during the online process, and saves the template after receiving the downlink frame sent by the OLT. The ONU parses the downlink frame according to the downlink PLOAM message. For example, the ONU receives the PLOAM message "0PP" as "00", indicating that the preamble (also can be a preamble) is the first preamble, wherein the preamble is 32 bytes, delimited The character is 4 bytes; if the ONU receives the PLOAM message "1PP" as "01", it means that the preamble is the second preamble, the preamble is 4 bytes, and the delimiter is 4 bytes. After the OLT performs master/standby switchover, the OLT sets the BurstProfile as the first leader in the downlink frame, and the ONU uses the 32-byte first leader uplink frame through the "00" uplink frame structure defined by the PLOAM message. send.

Embodiments of the present invention set the BurstProfile field in the frame header of the downlink XGTC frame as the first leading (long frame header), so that the ONU adopts the upstream frame of the first leading, so that after the OLT receives the upstream burst frame sent by the ONU, According to the first preamble, the position of receiving the upstream frame after switching can be determined, thereby obtaining the EqD deviation of the ONU, realizing the re-ranging process of the ONU, and solving the problem of not supporting the POPUP message after the active-standby switchover in the current PON system. The data communication between the OLT and the ONU is interrupted, and user satisfaction is improved.

Further, before sending the downlink frame, the OLT also includes: generating an uplink bandwidth authorization message, the authorization message includes bandwidth information indicating the uplink frame and preamble template information, and the preamble template information indicates that the at least one optical network unit adopts the first Sending an uplink frame as a preamble; encapsulating an uplink bandwidth authorization message into the downlink frame.

Step S310, the OLT detects the uplink frame containing the first preamble sent by the at least one ONU through the second OLT, and obtains the equalization delay of the at least one ONU based on the uplink frame containing the first preamble.

Step S312, the OLT sends the equalization delay to the at least one optical network unit through the second optical line terminal port, so that the at least one optical network unit is based on the equalization delay and the first Two optical line terminal ports for communication.

The OLT obtains the balanced time delay of other optical network units in the plurality of optical network units based on the balanced time delay sent by the second optical line terminal port; sends the balanced time delay of the other optical network units to the corresponding said other optical network unit; or,

The OLT obtains the equalized delay offset of the at least one optical network unit based on the equalized delay sent by the second optical line terminal port, and sends the equalized time shift offset to the plurality of optical network units other optical network units.

Wherein, the OLT obtains the balanced delay offset of the at least one optical network unit, and sending the balanced time shift offset to other optical network units in the plurality of optical network units specifically includes two ways:

One is, after the OLT sends the first equalization time delay EqD1 to the at least one ONU through the first sending port and the second equalization time delay EqD2 sent to the at least one ONU through the second sending port, Calculate the EqD offset of EqD1 and EqD2. At this time, the EqD offset can be estimated as the EqD offset of each ONU after switching from the first OLT port to the second OLT port. According to the EqD offset, other components in the optical network system can be calculated. EqD of each ONU, and deliver the EqD to each corresponding ONU in a unicast manner through the second OLT port.

The second is that after the OLT calculates the EqD deviation, it is broadcast to other ONUs in the optical network system through the second OLT port, and the other ONUs calculate the EqD after switching according to the EqD deviation, and then based on the described The switched EqD communicates with the OLT through the second OLT port.

The EqD mode of each ONU is sent in unicast mode, and it can be confirmed whether the main/standby switchover is successful or not through the message returned by each ONU.

In addition, when the ONU detects TYPEB protection switching, it immediately clears the EqD value of the original PON port and restores it to the default value of 0. Make the distance measurement after switching consistent with the distance measurement processing flow when the ONU goes online normally.

The embodiment of the present invention provides a data communication method in an optical network system. After the communication between the main terminal and multiple optical network units is switched from the first optical line terminal port to the second optical line terminal port, the second optical line The line terminal port sends a downlink frame to at least one optical network unit, and the downlink frame instructs the at least one optical network unit to use a first preamble to send an uplink frame, wherein the length of the first preamble is longer than the second preamble used for uplink service transmission. The length of the preamble: detecting the uplink frame containing the first preamble sent by the at least one optical network unit through the second optical line terminal port, and obtaining the at least one optical network unit based on the uplink frame containing the first preamble the equalized delay; send the equalized delay to the at least one optical network unit through the second optical line terminal port, so that the at least one optical network unit is based on the equalized delay and the second The optical line terminal port communicates, so that the optical network system can re-range the state even if it does not support the POPUP message after the switchover, and then quickly restore the data communication between the OLT and the ONU after the switchover, avoiding the normal business communication after the switchover Influence, reduce switching delay, improve user satisfaction, especially for XGPON system, further solve the problem of TYPEB active/standby switching in XGPON system.

FIG. 6 is a flow chart of another data communication method in an optical network system according to an embodiment of the present invention. As shown in Figure 6, the method of the embodiment of the present invention may include the following steps:

The central office of the optical network system provides a first optical line terminal port and a second optical line terminal port, each optical line terminal port is connected to a plurality of optical network units, and the method includes:

Step S602, after the communication between the authority terminal and the multiple ONUs is switched from the first OLT port to the second OLT port, the OLT sends a deactivation message or sends a redistributed message through the second OLT port. The message identified by the optical network unit is sent to at least one optical network unit, so that the at least one optical network unit goes offline.

Step S604, re-ranging the at least one ONU to obtain a first equalization delay of the at least one ONU.

Step S606, the OLT performs re-ranging on the ONU to obtain the first equalization delay of the ONU.

Step S608, the OLT sends the equalization delay to the at least one optical network unit through the second optical line terminal port, so that the at least one optical network unit is based on the equalization delay and the second optical network unit Line terminal port for communication.

The OLT obtains the balanced time delay of other optical network units in the plurality of optical network units based on the balanced time delay sent by the second optical line terminal port; sends the balanced time delay of the other optical network units to the corresponding said other optical network unit; or,

The OLT obtains the equalized delay offset of the at least one optical network unit based on the equalized delay sent by the second optical line terminal port, and sends the equalized time shift offset to the plurality of optical network units other optical network units.

Wherein, the OLT obtains the balanced delay offset of the at least one optical network unit, and sending the balanced time shift offset to other optical network units in the plurality of optical network units specifically includes two ways:

One is, after the OLT sends the first equalization time delay EqD1 to the at least one ONU through the first sending port and the second equalization time delay EqD2 sent to the at least one ONU through the second sending port, Calculate the EqD offset of EqD1 and EqD2. At this time, the EqD offset can be estimated as the EqD offset of each ONU after switching from the first OLT port to the second OLT port. According to the EqD offset, other components in the optical network system can be calculated. EqD of each ONU, and deliver the EqD to each corresponding ONU in a unicast manner through the second OLT port.

The second is that after the OLT calculates the EqD deviation, it is broadcast to other ONUs in the optical network system through the second OLT port, and the other ONUs calculate the EqD after switching according to the EqD deviation, and then based on the described The switched EqD communicates with the OLT through the second OLT port.

The EqD mode of each ONU is sent in unicast mode, and it can be confirmed whether the main/standby switchover is successful or not through the message returned by each ONU.

In addition, when the ONU detects TYPEB protection switching, it immediately clears the EqD value of the original PON port and restores it to the default value of 0. Make the distance measurement after switching consistent with the distance measurement processing flow when the ONU goes online normally.

The method adopted by the user terminal side corresponding to the above method, that is, the ONU side includes:

The ONU communicates with the first optical line terminal port based on the first equalization delay to perform service transmission;

Switching from the first OLT port to the second OLT port, receiving a deactivation message from the second OLT port or a message carrying a reallocated ONU identifier;

The ONU goes offline according to the deactivation message;

After the ONU performs ranging again, it receives the second equalization delay from the second optical line terminal port;

The ONU communicates with the second optical line terminal port based on the second equalization delay to perform service transmission.

In another data communication method in an optical network system provided by an embodiment of the present invention, after the communication between the main terminal and multiple optical network units is switched from the first optical line terminal port to the second optical line terminal port, through the second The optical line terminal port sends a deactivation message or sends a message carrying a redistributed optical network unit identifier to at least one optical network unit, so that the at least one optical network unit goes offline; re-ranges the at least one optical network unit , obtain the first equalization delay of the at least one optical network unit; send the equalization delay to the at least one optical network unit through the second optical line terminal port, so that the at least one optical network unit Communicate with the second optical line terminal port based on the equalized time delay, so that the optical network system can perform a re-ranging state even if it does not support POPUP messages after the switch, and then quickly restore the data between the OLT and the ONU after the switch Communication avoids the impact on normal business communication after handover, reduces handover delay, and improves user satisfaction.

As shown in Figure 7, Figure 7 is an optical network system provided by an embodiment of the present invention, the system includes: a first optical line terminal port and a second optical line terminal port, and the OLT connects multiple optical line terminal ports through each optical line terminal port an ONU;

The optical line terminal is configured to, after the communication between the optical line terminal and a plurality of optical network units is switched from the first optical line terminal port to the second optical line terminal port, send at least one optical line terminal through the second optical line terminal port The network unit sends a downlink frame, and the downlink frame instructs the at least one optical network unit to use a first preamble to send an uplink frame, wherein the length of the first preamble is greater than the length of a second preamble used for uplink service transmission; detecting the At least one optical network unit sends an uplink frame containing the first preamble through the second optical line terminal port, and based on the uplink frame containing the first preamble, obtain the equalization delay of the at least one optical network unit; through the The second OLT port sends the equalized time delay to the at least one ONU, so that the at least one ONU communicates with the second OLT port based on the equalized time delay.

The at least one optical network unit is used to communicate with the first optical line terminal port based on the first equalization delay to perform service transmission; switch from the first optical line terminal port to the second optical line terminal port, and receive information from the second optical line terminal port The downlink frame of the optical line terminal port, the downlink frame indicates that the uplink frame adopts the first preamble, wherein the length of the first preamble is greater than the length of the second preamble used for uplink service transmission; sending to the second optical line terminal port includes The first leading uplink frame; receiving a second equalization delay from the second optical line terminal port; communicating with the second optical line terminal port based on the second equalization delay to perform service transmission.

The optical line terminal is further configured to generate an uplink bandwidth authorization message, the authorization message includes bandwidth information indicating the uplink frame and preamble template information, and the preamble template information indicates that the at least one optical network unit uses the first preamble to send the uplink frame ; Encapsulate the uplink bandwidth authorization message into the downlink frame.

The optical line terminal is further configured to obtain the balanced delay of other optical network units in the plurality of optical network units based on the balanced delay sent by the second optical line terminal port; The equalization delay is sent to the corresponding other optical network units.

The optical line terminal is further configured to obtain an equalized delay offset of the at least one optical network unit based on the equalized delay sent by the port of the second optical line terminal, and send the equalized time shift offset to the Other optical network units in the plurality of optical network units.

An optical distribution network ODN is also included between the OLT and the ONU, and the ODN includes: a trunk optical fiber and a branch optical fiber.

The embodiment of the present invention also provides another optical network system, the system includes: a first optical line terminal port and a second optical line terminal port, and the optical line terminal is connected to a plurality of optical network units through each optical line terminal port;

The optical line terminal is configured to send a deactivation message through the second optical line terminal port after the communication between the optical line terminal and a plurality of optical network units is switched from the first optical line terminal port to the second optical line terminal port Or send a message carrying a redistributed ONU identifier to at least one ONU, so that the at least one ONU goes offline; re-range the at least one ONU to obtain the at least one ONU The first equalization delay of the unit; sending the equalization delay to the at least one optical network unit through the second optical line terminal port, so that the at least one optical network unit is based on the equalization delay and the communicating through the second optical line terminal port;

The optical network unit is configured to communicate with the first optical line terminal port based on the first equalization delay to perform service transmission; switch from the first optical line terminal port to the second optical line terminal port, and receive information from the second optical line terminal port The deactivation message of the terminal port or the message carrying the redistributed optical network unit identification; according to the deactivation message, go offline;

After re-ranging, receive a second equalization delay from the second optical line terminal port; communicate with the second optical line terminal port based on the second equalization delay to perform service transmission.

The optical line terminal is further configured to obtain the balanced delay of other optical network units in the plurality of optical network units based on the balanced delay sent by the second optical line terminal port; The equalization delay is sent to the corresponding other optical network units.

The optical line terminal is further configured to obtain an equalized delay offset of the at least one optical network unit based on the equalized delay sent by the port of the second optical line terminal, and send the equalized time shift offset to the Other optical network units in the plurality of optical network units.

The embodiment of the present invention provides a method for data communication in an optical network system, the system and an optical line terminal. After the communication between the main terminal and a plurality of optical network units is switched from the first optical line terminal port to the second optical line terminal port, Send a downlink frame to at least one optical network unit through the second optical line terminal port, the downlink frame instructs the at least one optical network unit to use the first preamble to send an uplink frame, or send a deactivation message or send a reallocation The message identified by the optical network unit is sent to at least one optical network unit, so that the optical network system can re-range the state even if it does not support the POPUP message after the switchover, and then quickly restore the data communication between the OLT and the ONU after the switchover, avoiding The impact on normal business communication after handover reduces handover delay and improves user satisfaction.

As shown in FIG. 8, an embodiment of the present invention provides an optical line terminal, and the optical line terminal includes:

The first sending unit 802 is configured to, when the communication between the OLT and multiple ONUs is switched from the first OLT port to the second OLT port, send at least An optical network unit sends a downlink frame, and the downlink frame instructs the at least one optical network unit to use a first preamble to send an uplink frame, wherein the length of the first preamble is greater than the length of a second preamble used for uplink service transmission;

The first obtaining unit 804 is configured to detect the uplink frame containing the first preamble sent by the at least one optical network unit through the second optical line terminal port; based on the uplink frame containing the first preamble, obtain the at least The equalization delay of an optical network unit;

The second sending unit 806 is configured to send the equalization delay of the at least one optical network unit to the at least one optical network unit through the second optical line terminal port, so that the at least one optical network unit is based on the The equalization delay is used to communicate with the second optical line terminal port.

The optical line terminal also includes:

A bandwidth authorization unit 808, connected to the first sending unit, configured to generate an uplink bandwidth authorization message, the authorization message includes bandwidth information indicating an uplink frame and preamble template information, and the preamble template information indicates the at least one optical network unit sending an uplink frame by using the first preamble; and encapsulating an uplink bandwidth authorization message into the downlink frame.

The second obtaining unit 810 is configured to obtain the balanced time delay of other optical network units in the plurality of optical network units based on the balanced time delay sent by the second optical line terminal port;

The second sending unit is further configured to send the equalization delays of the other ONUs to corresponding other ONUs.

The optical line terminal also includes:

The third obtaining unit 812 is configured to obtain the balanced delay offset of the at least one optical network unit based on the balanced delay sent by the second optical line terminal port;

The second sending unit is further configured to send the equalized time shift offset to other optical network units in the plurality of optical network units.

The embodiment of the present invention also provides an optical network unit, and the optical network unit includes:

The first receiving unit 902 is configured to communicate with the first optical line terminal port based on the first equalization delay to perform service transmission; switch from the first optical line terminal port to the second optical line terminal port, and receive data from the second optical line terminal port A downlink frame of a terminal port, where the downlink frame indicates that the uplink frame adopts a first preamble, wherein the length of the first preamble is greater than the length of the second preamble used for uplink service transmission;

The fifth sending unit 904 is configured to send the uplink frame including the first preamble to the second optical line terminal port;

The second receiving unit 906 is configured to receive a second equalization delay from the second optical line terminal port; and communicate with the second optical line terminal port based on the second equalization delay to perform service transmission.

In an optical line terminal provided by an embodiment of the present invention, after the communication between the main terminal and multiple optical network units is switched from the first optical line terminal port to the second optical line terminal port, at least An optical network unit sends a downlink frame, and the downlink frame instructs the at least one optical network unit to use a first preamble to send an uplink frame, wherein the length of the first preamble is greater than the length of the second preamble used for uplink traffic transmission; detection Based on the uplink frame containing the first preamble sent by the at least one optical network unit through the second optical line terminal port, the equalized delay of the at least one optical network unit is obtained based on the uplink frame containing the first preamble; Send the equalized delay to the at least one optical network unit through the second optical line terminal port, so that the at least one optical network unit communicates with the second optical line terminal port based on the equalized delay. Communication, after switching, the optical network system can re-range the state even if it does not support POPUP messages, and then quickly restore the data communication between the OLT and the ONU after switching, avoiding the impact on normal business communication after switching, reducing switching Delay improves user satisfaction, especially for XGPON systems, and further solves the problem of TYPEB active/standby switchover in XGPON systems.

As shown in Figure 10, the embodiment of the present invention also provides another optical line terminal, the optical line terminal includes:

The third sending unit 1002 is configured to, when the communication between the optical line terminal and multiple optical network units is switched from the first optical line terminal port to the second optical line terminal port, send the Activating a message or sending a message carrying a reallocated ONU identifier to at least one ONU, so that the at least one ONU goes offline;

The fourth obtaining unit 1004 is configured to re-range the at least one optical network unit, and obtain the first equalization delay of the at least one optical network unit;

The fourth sending unit 1006 is configured to send the equalized time delay to the at least one optical network unit through the second optical line terminal port, so that the at least one optical network unit is based on the equalized time delay and the communicate with the second optical line terminal port.

The optical line terminal also includes:

The fifth obtaining unit 1008 is configured to obtain the balanced time delay of other optical network units in the plurality of optical network units based on the balanced time delay sent by the second optical line terminal port;

The fourth sending unit is further configured to send the equalization delays of the other ONUs to corresponding other ONUs.

24. The optical line terminal according to claim 22, further comprising:

The sixth obtaining unit 1010 is configured to obtain the balanced delay offset of the at least one optical network unit based on the balanced delay sent by the second optical line terminal port;

The fourth sending unit is further configured to send the equalization delay offset to other optical network units in the plurality of optical network units.

In another optical line terminal provided by an embodiment of the present invention, after the communication between the main terminal and multiple optical network units is switched from the first optical line terminal port to the second optical line terminal port, the communication is sent through the second optical line terminal port. Deactivate a message or send a message carrying a reallocated ONU identifier to at least one ONU, so that the at least one ONU goes offline; re-measure the at least one ONU, and obtain the at least one ONU The first equalization delay of an optical network unit; sending the equalization delay to the at least one optical network unit through the second optical line terminal port, so that the at least one optical network unit is based on the equalization time delay Delay communication with the second optical line terminal port to realize the re-ranging state even if the optical network system does not support the POPUP message after the switch, and then quickly restore the data communication between the OLT and the ONU after the switch, avoiding the switch Afterwards, the normal service communication is affected, the handover delay is reduced, and the user satisfaction is improved.

Those of ordinary skill in the art can understand that all or part of the steps for realizing the above-mentioned method embodiments can be completed by hardware related to program instructions, and the aforementioned program can be stored in a computer-readable storage medium. When the program is executed, the It includes the steps of the above method embodiments; and the aforementioned storage medium includes: ROM, RAM, magnetic disk or optical disk and other various media that can store program codes.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: it can still be Modifications are made to the technical solutions described in the foregoing embodiments, or equivalent replacements are made to some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention.

Claims (24)

1. A communication method of an optical network system, the central office of the optical network system provides a first optical line terminal port and a second optical line terminal port, and each optical line terminal port is connected to a plurality of optical network units, characterized in that ,include: After the communication between the main terminal and the multiple optical network units is switched from the first optical line terminal port to the second optical line terminal port, a downlink frame is sent to at least one optical network unit through the second optical line terminal port, and the downlink frame is instructing the at least one optical network unit to use a first preamble to send an uplink frame, wherein the length of the first preamble is greater than the length of a second preamble used for uplink traffic transmission; Detecting an uplink frame containing a first preamble sent by the at least one optical network unit through the second optical line terminal port, and obtaining an equalized delay of the at least one optical network unit based on the uplink frame containing the first preamble ; Send the equalized delay to the at least one optical network unit through the second optical line terminal port, so that the at least one optical network unit communicates with the second optical line terminal port based on the equalized delay. communication. 2. The method according to claim 1, further comprising: before sending the downlink frame: generating an uplink bandwidth authorization message, the authorization message includes bandwidth information indicating the uplink frame and preamble template information, and the preamble template information indicates the at least one The optical network unit uses the first preamble to send the uplink frame; Encapsulating the uplink bandwidth grant message into the downlink frame. 3. The method according to claim 1 or 2, characterized in that the method further comprises: Obtaining the balanced delay of other optical network units in the plurality of optical network units based on the balanced delay sent by the second optical line terminal port; sending the equalization delays of the other ONUs to the corresponding other ONUs. 4. method according to claim 1 or 2, is characterized in that, described method also comprises: Based on the equalized delay sent by the second optical line terminal port, obtain the equalized delay offset of the at least one optical network unit, and send the equalized delay offset to other optical network units in the plurality of optical network units network unit. 5. A communication method for an optical network system, characterized in that the method comprises: Based on the first equalization delay and communicating with the first optical line terminal port, to perform service transmission; Switching from the first optical line terminal port to the second optical line terminal port, receiving a downlink frame from the second optical line terminal port, the downlink frame indicating that the uplink frame adopts a first preamble, wherein the length of the first preamble is greater than that used The length of the second preamble for uplink service transmission; sending an uplink frame including the first preamble to a second optical line terminal port; receiving a second equalization delay from a second optical line terminal port; Based on the second equalization delay, communicate with the second optical line terminal port to perform service transmission. 6. A communication method for an optical network system, the central office of the optical network system provides a first optical line terminal port and a second optical line terminal port, and each optical line terminal port is connected to a plurality of optical network units, characterized in that , the method includes: After the communication between the main terminal and multiple optical network units is switched from the first optical line terminal port to the second optical line terminal port, a deactivation message is sent through the second optical line terminal port or a message carrying a reallocated optical network unit identifier is sent. Send a message to at least one optical network unit, so that the at least one optical network unit goes offline; Re-ranging the at least one optical network unit to obtain a first equalization delay of the at least one optical network unit; Send the equalized delay to the at least one optical network unit through the second optical line terminal port, so that the at least one optical network unit communicates with the second optical line terminal port based on the equalized delay. communication. 7. The method according to claim 6, further comprising: Obtaining the balanced delay of other optical network units in the plurality of optical network units based on the balanced delay sent by the second optical line terminal port; sending the equalization delays of the other ONUs to the corresponding other ONUs. 8. The method according to claim 6, further comprising: Based on the equalized delay sent by the second optical line terminal port, obtain the equalized delay offset of the at least one optical network unit, and send the equalized delay offset to other optical network units in the plurality of optical network units network unit. 9. A communication method for an optical network system, characterized in that the method comprises: Based on the first equalization delay and communicating with the first optical line terminal port, to perform service transmission; Switching from the first OLT port to the second OLT port, receiving a deactivation message from the second OLT port or a message carrying a reallocated ONU identifier; Go offline according to the deactivation message; After re-ranging, receive the second equalization delay from the second optical line terminal port; Based on the second equalization delay, communicate with the second optical line terminal port to perform service transmission. 10. An optical network system, characterized in that the system comprises: a first optical line terminal port and a second optical line terminal port, and the optical line terminal is connected to a plurality of optical network units through each optical line terminal port; The optical line terminal is configured to, after the communication between the optical line terminal and a plurality of optical network units is switched from the first optical line terminal port to the second optical line terminal port, send at least one optical line terminal through the second optical line terminal port The network unit sends a downlink frame, and the downlink frame instructs the at least one optical network unit to use a first preamble to send an uplink frame, wherein the length of the first preamble is greater than the length of a second preamble used for uplink service transmission; detecting the At least one optical network unit sends an uplink frame containing the first preamble through the second optical line terminal port, and based on the uplink frame containing the first preamble, obtain the equalization delay of the at least one optical network unit; through the The second OLT port sends the equalized delay to the at least one optical network unit, so that the at least one optical network unit communicates with the second OLT port based on the equalized delay; The at least one optical network unit is used to communicate with the first optical line terminal port based on the first equalization delay to perform service transmission; switch from the first optical line terminal port to the second optical line terminal port, and receive information from the second optical line terminal port The downlink frame of the optical line terminal port, the downlink frame indicates that the uplink frame adopts the first preamble, wherein the length of the first preamble is greater than the length of the second preamble used for uplink service transmission; sending to the second optical line terminal port includes The first leading uplink frame; receiving a second equalization delay from the second optical line terminal port; communicating with the second optical line terminal port based on the second equalization delay to perform service transmission. 11. The optical network system according to claim 10, wherein the optical line terminal is further configured to generate an uplink bandwidth authorization message, the authorization message includes bandwidth information indicating an uplink frame and preamble template information, and the preamble The template information instructs the at least one optical network unit to use the first preamble to send the uplink frame; and encapsulates the uplink bandwidth authorization message into the downlink frame. 12. The optical network system according to claim 10 or 11, wherein the optical line terminal is further configured to obtain the plurality of optical network delays based on the equalization delay sent by the second optical line terminal port The equalization delay of other optical network units in the unit; sending the equalization delay of the other optical network units to the corresponding other optical network units. 13. The optical network system according to claim 10 or 11, wherein the optical line terminal is further configured to obtain the at least one optical network time delay based on the equalization delay sent by the port of the second optical line terminal the equalized delay offset of the unit, and send the equalized delay offset to other optical network units in the plurality of optical network units. 14. An optical network system, characterized in that the system comprises: a first optical line terminal port and a second optical line terminal port, and the optical line terminal is connected to a plurality of optical network units through each optical line terminal port; The optical line terminal is configured to send a deactivation message through the second optical line terminal port after the communication between the optical line terminal and a plurality of optical network units is switched from the first optical line terminal port to the second optical line terminal port Or send a message carrying a redistributed ONU identifier to at least one ONU, so that the at least one ONU goes offline; re-range the at least one ONU to obtain the at least one ONU The first equalization delay of the unit; sending the equalization delay to the at least one optical network unit through the second optical line terminal port, so that the at least one optical network unit is based on the equalization delay and the communicating through the second optical line terminal port; The optical network unit is configured to communicate with the first optical line terminal port based on the first equalization delay to perform service transmission; switch from the first optical line terminal port to the second optical line terminal port, and receive information from the second optical line terminal port The deactivation message of the terminal port or the message carrying the redistributed optical network unit identification; according to the deactivation message, go offline; After re-ranging, receive a second equalization delay from the second optical line terminal port; communicate with the second optical line terminal port based on the second equalization delay to perform service transmission. 15. The optical network system according to claim 14, wherein the optical line terminal is further configured to obtain, among the plurality of optical network units, based on the equalized time delay sent by the second optical line terminal port The equalization delay of other optical network units; sending the equalization delays of the other optical network units to the corresponding other optical network units. 16. The optical network system according to claim 14, wherein the optical line terminal is further configured to obtain the time delay of the at least one optical network unit based on the equalization delay sent by the second optical line terminal port equalize the delay offset, and send the equalized delay offset to other optical network units in the plurality of optical network units. 17. An optical line terminal, characterized in that the optical line terminal comprises: The first sending unit is configured to, when the communication between the optical line terminal and multiple optical network units is switched from the first optical line terminal port to the second optical line terminal port, send the communication to at least one of the optical line terminal ports through the second optical line terminal port The optical network unit sends a downlink frame, and the downlink frame instructs the at least one optical network unit to use a first preamble to send an uplink frame, wherein the length of the first preamble is greater than the length of the second preamble used for uplink traffic transmission; The first acquisition unit is configured to detect the uplink frame containing the first preamble sent by the at least one optical network unit through the second optical line terminal port; based on the uplink frame containing the first preamble, obtain the at least one The equalization delay of the optical network unit; The second sending unit is configured to send the equalization delay of the at least one optical network unit to the at least one optical network unit through the second optical line terminal port, so that the at least one optical network unit is based on the The equalization delay communicates with the second optical line terminal port. 18. The optical line terminal according to claim 17, wherein the optical line terminal further comprises: A bandwidth authorization unit, connected to the first sending unit, configured to generate an uplink bandwidth authorization message, the authorization message includes bandwidth information indicating an uplink frame and preamble template information, and the preamble template information indicates that the at least one optical network unit adopts The first preamble sends an uplink frame; and encapsulates an uplink bandwidth authorization message into the downlink frame. 19. The optical line terminal according to claim 17 or 18, wherein the optical line terminal further comprises: The second obtaining unit is configured to obtain the balanced time delay of other optical network units in the plurality of optical network units based on the balanced time delay sent by the second optical line terminal port; The second sending unit is further configured to send the equalization delays of the other ONUs to corresponding other ONUs. 20. The optical line terminal according to claim 17 or 18, wherein the optical line terminal further comprises: A third obtaining unit, configured to obtain the balanced delay offset of the at least one optical network unit based on the balanced delay sent by the second optical line terminal port; The second sending unit is further configured to send the equalization delay offset to other optical network units in the plurality of optical network units. 21. An optical network unit, characterized in that the optical network unit comprises: The receiving unit is configured to communicate with the first optical line terminal port based on the first equalization delay to perform service transmission; switch from the first optical line terminal port to the second optical line terminal port, and receive the signal from the second optical line terminal port A downlink frame, where the downlink frame indicates that the uplink frame adopts a first preamble, wherein the length of the first preamble is greater than the length of the second preamble used for uplink service transmission; a fifth sending unit, configured to send the uplink frame including the first preamble to the second optical line terminal port; The second receiving unit is configured to receive the second equalized delay from the second optical line terminal port; communicate with the second optical line terminal port based on the second equalized delay to perform service transmission. 22. An optical line terminal, characterized in that the optical line terminal comprises: The third sending unit is configured to send deactivation through the second optical line terminal port after the communication between the optical line terminal and multiple optical network units is switched from the first optical line terminal port to the second optical line terminal port message or send a message carrying the reallocated ONU identifier to at least one ONU, so that the at least one ONU goes offline; The fourth obtaining unit is configured to re-range the at least one optical network unit, and obtain the first equalization delay of the at least one optical network unit; A fourth sending unit, configured to send the equalized time delay to the at least one optical network unit through the second optical line terminal port, so that the at least one optical network unit is based on the equalized time delay and the The second optical line termination port communicates. 23. The optical line terminal according to claim 22, wherein the optical line terminal further comprises: The fifth obtaining unit is configured to obtain the balanced time delay of other optical network units in the plurality of optical network units based on the balanced time delay sent by the second optical line terminal port; The fourth sending unit is further configured to send the equalization delays of the other ONUs to corresponding other ONUs. 24. The optical line terminal according to claim 22, wherein the optical line terminal further comprises: A sixth obtaining unit, configured to obtain the equalized delay offset of the at least one optical network unit based on the equalized delay sent by the second optical line terminal port; The fourth sending unit is further configured to send the equalization delay offset to other optical network units in the plurality of optical network units.