WO2011144110A2

WO2011144110A2 - Method, system and device for communication in the optical network system

Info

Publication number: WO2011144110A2
Application number: PCT/CN2011/074789
Authority: WO
Inventors: 万民; 韦永泉
Original assignee: 华为技术有限公司
Priority date: 2011-05-27
Filing date: 2011-05-27
Publication date: 2011-11-24
Also published as: CN102648590A; WO2011144110A3; CN102648590B

Abstract

A method, system and device for data communication in an optical network system are provided in the embodiment of the present invention. After the communication between the central office and multiple optical network units (ONUs) is switched to a second optical line terminal (OLT) port from a first OLT port, a downlink frame, which indicates that at least one ONU sends a uplink frame with a first preamble, is sent to at least one optical network unit (ONU) via the second OLT port; or, a deactivation message or a message carrying a reassigned ONU identifier are sent to at least one ONU. The present invention implements that the switched optical network system even without supporting a POPUP message can also perform ranging again. Moreover, the data communication between the switched OLT and the ONU can swiftly recovered, the influence for the normal service communication after being switched can be avoided, the switching delay is decreased, and the user satisfaction is improved.

Description

Communication method, system and device for optical network system

The present invention relates to the field of communications technologies, and in particular, to a communication method, system, and apparatus for an optical network system. Background technique

Passive Optical Network (PON) technology is one of the most widely used Fiber To The Home (FTTH) technologies. The existing PON includes a Broadband Passive Optical Network (BPON), a Gigabit-Capable Passive Optical Network (GPON), and an Ethernet Passive Optical Network (EPON). And 10 Gigabit-capable Passive Optical Networks (XG-P0N).

The traditional PON system mainly includes: an optical line terminal (OLT), an optical network unit (0NU), and an optical distribution network (ODN), wherein the optical distribution network includes a backbone. Fiber optics, passive optical splitters, and branch fibers. The 0LT and the passive optical splitter are connected by a backbone optical fiber, and the optical splitter realizes point-to-multipoint optical power distribution and is connected to multiple 0NUs through multiple branch fibers. The direction from 0LT to 0NU is called the downlink direction, and the direction from 0NU to 0LT is called the uplink direction.

The uplink direction of the P0N system is usually a Time Division Multiple Address (TDMA) multiplexing mode. Each ONU sends uplink data packets in the time slot specified by the OLT. The downlink direction 0LT uses Time Division Multiplexing (TDM). The broadcast mode sends downlink data packets to each 0NU. The optical signals carrying all the ONU downlink data packets are divided into several parts at the 0DN optical splitter, and each branch fiber reaches each ONU.

Among them, in the GP0N system, when the optical fiber between the primary 0LT and the 0NU fails, the LOS (lost of signal) alarm is detected because the receiver receives the signal of the other party; the primary 0LT is used. The L0S alarm is detected, indicating that the primary trunk fiber is faulty. The active and standby 0LT switches are required. All the 0NUs are switched to the standby 0LT, and the original standby 0LT is switched to become the primary OLT. After detecting the L0S alarm, 0NU switches from the normal OPERATION state to the POPUP state and stops sending uplink data. The primary 0LT sends a POPUP message to all 0NU broadcasts, notifying the 0NU to transition from the POPUP state to the RANGING state, and starting all 0NU re-ranging. Processing; under the control of the main 0LT, serial processing completes all 0NU ranging processing, and restores data communication between 0LT and 0NU.

In the process of implementing the present invention, the inventors have found that the prior art has at least the following problems:

When the primary optical fiber between the 0LT and the 0NU fails, the primary and backup backbone fibers need to be re-ranged for each 0NU. Since the XGP0N system or other optical network system does not support the POPUP message, the 0NU cannot enter the re-ranging state. As a result, the ONU cannot obtain an accurate equalization delay, and the communication between the 0LT and the ONU is interrupted after the active/standby switchover. Summary of the invention

The object of the embodiments of the present invention is to provide a communication method, system, and device for an optical network system, which is used to solve the problem between the 0LT and the ONU after the OLT is not supported by the OLT in the existing optical network system. The problem of data communication interruption, thereby avoiding the impact on normal business communication after switching, and improving user satisfaction.

To solve the above problem, an embodiment of the present invention provides a communication method of an optical network system, where a central end 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. a plurality of optical network units, the method comprising:

After the communication between the authority and the plurality of optical network units is switched from the first optical line terminal port to the second optical line terminal port, the downlink frame is sent to the at least one optical network unit by the second optical line terminal port, where the downlink frame is Instructing the at least one optical network unit to transmit an uplink frame by using a first preamble, wherein a length of the first preamble is greater than a length of a second preamble for uplink traffic transmission;

Detecting, by the at least one optical network unit, an uplink frame that includes the first preamble sent by the second optical line terminal port, and obtaining an equalization delay of the at least one optical network unit based on the uplink frame that includes the first preamble Transmitting the equalization delay to the at least one optical network unit by the second optical line termination port, so that the at least one optical network unit is based on the equalization delay and the second optical line termination port Communicate.

An embodiment of the present invention further provides a communication method of another optical network system, where the method includes:

Performing service transmission based on the first equalization delay and the first optical line terminal port communication;

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, 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 of the uplink traffic transmission;

Transmitting, to the second optical line terminal port, an uplink frame including the first preamble;

Receiving a second equalization delay from the second optical line terminal port;

And performing traffic transmission based on the second equalization delay and the second optical line terminal port communication.

The present invention also provides a communication method of another optical network system, where the central end 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 multiple optical network units, The method includes: after the communication between the authority end and the plurality of optical network units is switched from the first optical line termination port to the second optical line termination port, sending a deactivation message or transmitting carrying a redistribution through the second optical line termination port Optical network unit Obtaining the message to the at least one optical network unit, causing the at least one optical network unit to go offline;

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

Transmitting the equalization delay to the at least one optical network unit by using the second optical line termination port, so that the at least one optical network unit performs the equalization delay and the second optical line termination port. Communication.

The embodiment of the invention further provides a communication method of an optical network system, where the method includes:

Switching from the first optical line termination port to the second optical line termination port, receiving a deactivation message from the second optical line termination port or carrying a message of the reassigned optical network unit identifier;

Performing offline according to the deactivation message;

After performing ranging again, receiving a second equalization delay from the second optical line terminal port;

And performing traffic transmission based on the second equalization delay and the second optical line terminal port communication. An embodiment of the present invention provides an optical network system, where the system includes: a first optical line terminal port and a second optical line terminal port, where the optical path terminal connects the plurality of optical network units through each optical line terminal port;

The optical line terminal is configured to: when the communication between the optical line terminal and the plurality of optical network units is switched from the first optical line terminal port to the second optical line terminal port, to the at least one light through the second optical line terminal port The network unit sends a downlink frame, where the downlink frame indicates that the at least one optical network unit uses the first preamble to send an uplink frame, where the length of the first preamble is greater than the length of the second preamble used for uplink service transmission; Obtaining an equalization delay of the at least one optical network unit based on the uplink frame including the first preamble by using the uplink frame that includes the first preamble sent by the second optical line terminal port by the at least one optical network unit; The second optical line terminal port transmits the equalization delay to the at least one optical network unit, so that the at least one optical network unit communicates with the second optical line terminal port based on the equalization delay.

The at least one optical network unit is configured to perform traffic transmission based on the first equalization delay and the first optical line terminal port; switch from the first optical line terminal port to the second optical line terminal port, and receive from the second a downlink frame of the optical line terminal port, where the downlink frame indicates that the uplink frame adopts a first preamble, wherein a length of the first preamble is greater than a length of a second preamble used for uplink service transmission; and sending, to the second optical line terminal port, An uplink frame of the first preamble; receiving a second equalization delay from the second optical line termination port; and performing traffic transmission based on the second equalization delay and the second optical line termination port communication.

Another embodiment of the present invention provides an optical network system, where the system includes: a first optical line terminal port and a a second optical line terminal port, the optical line terminal is connected to the plurality of optical network units through each optical line terminal port; the optical line terminal is configured to communicate with the optical line terminal and the plurality of optical network units from the first optical line terminal port After switching to the second optical line terminal port, sending a deactivation message through the second optical line terminal port or sending a message carrying the reassigned optical network unit identifier to the at least one optical network unit, so that the at least one optical network unit Performing re-ranging on the at least one optical network unit to obtain a first equalization delay of the at least one optical network unit; and transmitting, by the second optical line termination port, the equalization delay to the At least one optical network unit, such that the at least one optical network unit communicates with the second optical line termination port based on the equalization delay;

The optical network unit is configured to perform traffic transmission based on the first equalization delay and the first optical line terminal port; switch from the first optical line terminal port to the second optical line terminal port, and receive the second optical line a deactivation message of the terminal port or a message carrying the reassigned optical network unit identifier; performing a downlink according to the deactivation message; and after receiving the ranging, receiving a second equalization delay from the second optical line terminal port; And performing traffic transmission based on the second equalization delay and the second optical line terminal port communication.

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

a first sending unit, configured to: when the communication between the optical line terminal and the plurality of optical network units is switched from the first optical line terminal port to the second optical line terminal port, to the at least one through the second optical line terminal port The optical network unit sends a downlink frame, where the downlink frame indicates that the at least one optical network unit uses the first preamble to send an uplink frame, where the length of the first preamble is greater than the length of the second preamble used for uplink service transmission;

a first acquiring unit, configured to detect an uplink frame that includes the first preamble sent by the at least one optical network unit by using the second optical line terminal port; and obtain the at least one based on the uplink frame that includes the first preamble Equilibrium delay of the optical network unit;

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

An embodiment of the present invention further provides an optical network unit, where the optical network unit includes:

a receiving unit, configured to perform communication according to the first equalization delay and the first optical line terminal port to perform service transmission; switch from the first optical line terminal port to the second optical line terminal port, and receive the second optical line terminal port a downlink frame, where the downlink frame indicates that the uplink frame adopts a first preamble, where a length of the first preamble is greater than a length of a second preamble used for uplink service transmission; a fifth sending unit, configured to send, to the second optical line terminal port, an uplink frame that includes the first preamble; and a second receiving unit, configured to receive a second equalization delay from the second optical line terminal port; The second equalization delay communicates with the second optical line terminal port for service transmission.

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

a third sending unit, configured to send, by the second optical line terminal port, deactivation after the optical line terminal and the plurality of optical network units are switched from the first optical line terminal port to the second optical line terminal port Sending, by the message, a message carrying the reassigned optical network unit identifier to the at least one optical network unit, such that the at least one optical network unit is offline;

a fourth acquiring unit, configured to perform re-ranging on the at least one optical network unit, to obtain a first equalization delay of the at least one optical network unit;

a fourth sending unit, configured to send the equalization delay to the at least one optical network unit by using the second optical line terminal port, so that the at least one optical network unit is based on the equalization delay and the The second optical line terminal P communicates.

A method, system and device for data communication in an optical network system provided by an embodiment of the present invention, after communication between a authority end and a plurality of optical network units is switched from a first optical line terminal port to a second optical line terminal port, The second optical line terminal port sends a downlink frame to the at least one optical network unit, where the downlink frame indicates that the at least one optical network unit sends the uplink frame by using the first preamble, or sends a deactivation message or sends the light that carries the reallocation. The message identified by the network unit is sent to at least one optical network unit, so that after the switching, the optical network system can perform the re-ranging state even if the POPUP message is not supported, thereby quickly recovering the data communication between the 0LT and the ONU after the switching, thereby avoiding the switching. The impact on normal business communication reduces the switching delay and improves user satisfaction. BRIEF DESCRIPTION OF THE DRAWINGS In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments will be briefly described below. Obviously, the drawings in the following description are only some of the embodiments of the present invention, and those skilled in the art can obtain other drawings based on these drawings without any creative work.

1 is a flowchart of a data communication method of an optical network system according to an embodiment of the present invention;

2 is a schematic diagram of a state of an optical network unit according to an embodiment of the present invention;

FIG. 3 is a flowchart of a specific method for a data communication method of an optical network system according to an embodiment of the present disclosure; FIG. 4 is a schematic structural diagram of a downlink XGTC frame according to an embodiment of the present disclosure;

FIG. 5 is a schematic structural diagram of a BWMAP in a downlink XGTC frame structure according to an embodiment of the present disclosure;

6 is a flowchart of another optical network system data communication method according to an embodiment of the present invention;

FIG. 7 is a schematic structural diagram of an optical network system according to an embodiment of the present disclosure;

FIG. 8 is a schematic structural diagram of an optical line terminal according to an embodiment of the present disclosure;

FIG. 9 is a schematic structural diagram of an optical network unit according to an embodiment of the present disclosure;

FIG. 10 is a schematic structural diagram of another optical line terminal according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The technical solutions in the embodiments of the present invention will be clearly and completely described in the following with reference to the accompanying drawings. It is apparent that the described embodiments are only a part of the embodiments 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.

FIG. 1 is a flowchart of a data communication method of a passive optical network system according to an embodiment of the present invention. As shown in FIG. 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 0LT port and a second 0LT port, and each 0LT port is connected to multiple 0NUs, and the method includes:

Step S102: After the communication between the authority end and the plurality of ONUs is switched from the first OLT port to the second OLT port, send a downlink frame to the at least one ONU by using the second OLT port, where the downlink frame indicates the at least one optical network The unit uses the first preamble to send an uplink frame, where 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-P0N system (or abbreviated as XGP0N), and the XGP0N system includes: an XGP0N1 system and an XGP0N2 system, the two systems are next generation Gigabit The two main alternative architectures of the bit passive optical network NGP0N 1 (also known as the "next generation Gigabit Passive Optical Network"). XGP0N1 is an asymmetric system with downlink lOGbps/uplink 2. 5Gbps; XGP0N2 is a symmetric system with uplink and downlink lOGbps. The XGP0N1 system is an asymmetric system, which may also be called 10GGP0N; the central office is a network side device, which is relative to the user equipment, for example, 0LT. The embodiment of the present invention is described by taking only 0NU as an example, and all methods applicable to 0NU are applicable to 0NT.

Further, the downlink frame may be an XGTC frame. The uplink burst (frame) template Burst Profi le field in the downlink frame is set as a first preamble, which may also be referred to as a long preamble (also referred to as a long frame header), in the downlink frame. The Burst Profile field includes a first preamble and a second preamble (which may be referred to as a short preamble or a short frame header), wherein the length of the first preamble is greater than the length of the second preamble for uplink traffic transmission, the field is used to indicate at least An optical network unit uses an upstream frame of which preamble bytes are used. The first preamble is a preamble used when the 0NU enters the ranging state, that is, the 04 state, and the second preamble is used when the 0NU is in the running state, that is, the 05 state. Leading.

Further, before the sending of the downlink frame, the OLT further includes: generating an uplink bandwidth grant message, where the grant message includes bandwidth information indicating the uplink frame and preamble template information, where the preamble template information indicates that the at least one optical network unit adopts A preamble sends an uplink frame; and an uplink bandwidth grant message is encapsulated into the downlink frame.

Step S104: The 0LT detects an uplink frame that includes the first preamble sent by the at least one ONU through the second OLT port.

Step S106: The 0LT obtains an equalization delay of the at least one optical network unit based on the uplink frame that includes the first preamble.

Step S108: The 0LT sends the equalization delay to the at least one optical network unit by using the second optical line terminal port, so that the at least one optical network unit is based on the equalization delay and the first The two optical line terminal ports communicate.

Further, the method further includes: obtaining, by the OLT, an equalization delay of other optical network units in the plurality of optical network units based on an equalization 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 0LT obtains an equalization delay offset of the at least one optical network unit based on the equalization delay sent by the second optical line terminal port, and sends the equalization time shift offset to the multiple optical network units. Other optical network units.

The 0LT obtains an equalization delay offset of the at least one optical network unit, and the equalization time shift is sent to the other optical network units of the multiple optical network units, and specifically includes two modes:

The first time is that the 0LT is sent according to the first equalization delay EqD1 sent by the first sending port to the at least one ONU, and after the second equalization delay EqD2 sent by the second sending port to the at least one ONU. Calculating the EqD offset of EqD1 and EqD2. At this time, the EqD offset can be estimated as the EqD deviation of each 0NU after switching from the first 0LT port to the second OLT port, and further calculating the other in the optical network system according to the EqD deviation. Each ENU of the ONU is sent to the corresponding ONU in a unicast manner through the second 0LT port.

The second is that after the 0LT calculates the EqD deviation, it is broadcasted to the other ONUs in the optical network system through the second 0LT port, and the other ONUs respectively calculate the switched EqD according to the EqD deviation, and then based on the Switched EqD Communicating with the OLT through the second OLT port.

With respect to the above communication method, for 0NU, the method performed on the 0NU side includes:

The 0NU 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 0NU receives the downlink frame from the second optical line terminal port, and 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 traffic transmission;

The 0NU sends an uplink frame including the first preamble to the second optical line terminal port;

0NU receives a second equalization delay from the second optical line terminal port;

The 0NU communicates with the second optical line terminal port based on the second equalization delay for traffic transmission.

The method for data communication in an optical network system provided by the embodiment of the present invention, after the communication between the authority end and the plurality of optical network units is switched from the first optical line terminal port to the second optical line terminal port, the second light is passed. The line terminal port sends a downlink frame to the at least one optical network unit, where the downlink frame indicates that the at least one optical network unit uses the first preamble to send an uplink frame, where the length of the first preamble is greater than the second for uplink service transmission. Detecting the length of the preamble; detecting, by the at least one optical network unit, an uplink frame that includes the first preamble sent by the second optical line termination port, and obtaining the at least one optical network unit based on the uplink frame that includes the first preamble Equilibrium delay; transmitting, by the second optical line termination port, the equalization delay to the at least one optical network unit, so that the at least one optical network unit is based on the equalization delay and the second The optical line terminal port communicates, and the optical network system can perform re-testing even if the POPUP message is not supported after the handover. The state, in turn, quickly restores the data communication between the 0LT and the 0NU after the handover, avoids the impact on the normal service communication after the handover, reduces the handover delay, and improves the user satisfaction, especially for the XGP0N system, further solving The problem of TYPE B active/standby switchover in the XGP0N system.

FIG. 2 is a schematic diagram of a state of an optical network unit according to an embodiment of the present invention, and is specifically a schematic diagram of various states of an optical network unit in an XGP0N system. The XP0N system is taken as an example to describe the communication methods in the optical network system described above by introducing various state diagrams of the 0NU in the XP0N system.

As shown in Figure 2, the state change of the 0NU has six states:

( 1 ) 01 - Initial state

Initial state, optical transmission is off, all transmission control TC layer configuration parameters include 0NU-ID, default or explicit bandwidth allocation identifier Alloc-Id is the 0NU flag, when 0NU is synchronized with the downstream optical signal, it switches to the 02_3 state.

( 2) 02-3 - Serial Number state

Serial number SN status, 0NU activates the optical transmission function, receives and learns the Burst template (ie, the template of the uplink burst frame) The PLOAM message, when the ONU receives the SN windowing message with the known Burst template, sends an XGTC frame with the SN response physical layer operation management and maintenance PL0AM. At this time, the 0NU ignores the uplink dynamic bandwidth report DBRu identifier and the bandwidth mapping authorization width. BWMAP GrantSize area. When the ONU receives the PL0AM message with the sequence number SN equal to its own SN assigning the 0NU-ID, the 0NU enters the 04 state. When receiving a non-enable serial number Disable_Serial_Number PLOAM message whose SN is equal to its own SN, the ONU enters the 07 state. If the 0LT has learned the existence of the ONU in some way, for example, during the power failure recovery process, the 0LT can directly transmit an ONU-ID PL0AM message with a known ONU SN, so that the 0NU can ignore the 02-3 state. Go directly to the 04 state.

( 3) 04 - Ranging state

Ranging status, if 0NU receives a ranging request with a known template, it responds to an XGTC frame with a registered registration PLOAM, ignoring the DBRu flag and GrantSize area during ranging. The 0NU status of the 04 status is as follows: Template Prof i le (upstream burst frame template), ranging time Ranging—Time, deactivate the optical network identifier Deactivate— 0NU-ID, non-enable serial number Disable— Serial—Number. Timer T01 times out, 0NU discards the optical network unit ID ONU-ID and the default Alloc-ID and the default optical network unit management control interface XGP0N encapsulation mode port identifier 0MCI XGEM port-ID, and enters the 02-3 state, retaining the uplink Send frame BurstFrame template information. When the 0NU receives an EQD message with an absolute value of the equalization delay, it enters the 05 state. If the round-trip delay RTD of the 0NU has been tested before the 0LT is confirmed by the SN or during the activation of the early 0NU, the 0LT can directly send a Ranging_Time message, so that the 0NU can directly enter the 05 state. State without going through the ranging process.

(4) 05 - Operation state

Running state, at this time 0NU is in normal operation, and data communication is performed with 0LT.

( 5) 06 - Intermittent L0DS state

If the downlink signal is lost before the timer T02 expires, the L0DS state is restored, then it returns to the 05 state. If there is no L0DS recovery before T02 expires, it enters the 01 state.

(6) 07 - Emergency Stop state

In the emergency stop state, the 0NU receives the disable serial number Disable SN message (enables the disable enable field to be disabled), turns off the transmit light, and transmits the configuration parameters of the TC layer including: Optical network unit identifier 0NU-ID, all The allocation ID Alloc-ID, the default XGEM Port-ID, the burst template, and the EqD are all discarded. In the 07 state, the 0NU maintains downlink synchronization, parses the downlink PL0AM message, and prohibits downlink forwarding data and uplink transmission data. When re-enabled, 0LT sends a non-enable serial number Disable SN message ("Enable Disable" field is enabled), 0NU should enter the 01 state and go online again. When the 07 state 0NU is restarted, 0NU should remain in the 07 state. The timer T01 Ranging timer is the ranging timeout timer. The ONU can't be in the ranging state for too long. The standard recommendation is 10 seconds. In the 05 state, the ranging state timeout timer will be stopped. The timer T02 L0DS timer is the downlink signal. Loss of Downstream Signal (LODS) timeout timer ensures that the ONU is not in the 06 state for too long. The standard recommended 06 state time is 100ms.

The specific method flow of the data communication method of the passive optical network system provided by the embodiment of the present invention shown in FIG. 3 is described in detail below with reference to the ONU state diagram of FIG. 2, and the method of the embodiment of the present invention may include the following steps. :

Step S302: When the optical fiber between 0LT and ONU is faulty, 0LT detects a signal loss L0S alarm, starts a handover process, and the 0LT switches from the first 0LT port to the second 0LT port, and switches all 0NUs to the second 0LT. On the port.

Further, before the switching, the first 0LT port does not have an uplink optical signal, and the 0LT determines to enter the TYPE B protection process, that is, performs an active/standby switchover, switches the first 0LT port to the second 0LT port, and then switches all the ONUs. Go to the second 0LT port.

After detecting the LODS alarm, the 0NU is switched from the normal Operation State to the Intermittent LODS State state, and the uplink data is stopped.

The 0NU in this step can detect L0DS for at least one 0NU, the 0NU transitions from the 05 state to the 06 state, and the other 0NUs perform similar operations (see Figure 4).

Step S306: The downlink illumination of the second 0LT port (no bandwidth allocated), all the uplink bandwidth is turned off, and after waiting for a period of time, the 0NU enters the Operation State from the Intermittent LODS State.

According to the ONU state diagram of FIG. 2, when any ONU detects the LODS alarm, it enters the 06 state and starts the T02 timer. If the LO2 alarm is detected before the TO2 timer expires, the ONU jumps directly to 05 state, if the timer has not recovered after the timeout, it enters the 01 state.

Step S308, 0LT selects at least one ONU from the ONU that enters the Operation State, and sends a downlink frame to the at least one ONU, where the downlink frame indicates that the at least one optical network unit sends the uplink frame by using the first preamble, where The length of the first preamble is greater than the length of the second preamble for uplink traffic transmission.

Here, the number of 0NUs that re-enter the 05 state can be multiple or one, because the time of each 0NU entering the 05 state is different, so as long as there is a 0NU entering the 05 state, 0LT can perform step S208 on the 0NU, of course, The 0LT may also select one or more of the plurality of ONUs that enter the 05 state to perform step S208.

Specifically, after the 0LT selects at least one ONU, the Burst Profile field in the downlink frame is set as the first preamble, and is used to indicate that the selected ONU adopts an uplink frame using the first preamble preamble. The Burst Profile field is in the frame header portion of the downlink frame, and the XGTC frame in the XGP0N is taken as an example to describe how to set the Burst Prof ile field. The long preamble is set, but the embodiment of the present invention is not limited to the XGP0N system and is applicable to any type of passive optical network system.

The XGTC frame of the XG-P0N is taken as an example to describe the frame structure of the XGTC in detail. As shown in Figure 4, Figure 4 is a schematic diagram of the frame structure of the downlink XGTC frame.

The downlink XGTC frame has 135,432 bytes, including: an XGTC frame header and an XGTC payload. The XGTC header includes: HLend, which is used to represent the number of BWmaps and the number of PLOAMs; and the bandwidth mappings BWmap and PL0AMd. The specific BWmap structure is shown in Figure 5. One

FIG. 5 is a schematic diagram of a BWmap structure. The BWmap includes: an allocation structure, an Allocation Structure, and the number of the allocation structure varies with N, including: an uplink burst (frame) template Burst Profile, 2 bits, used to indicate an ONU The uplink frame of which preamble is used, or the uplink frame indicating which frame header is used by the ONU (where the uplink frame is the uplink burst frame), the general Burst Profile includes: a first preamble (also referred to as a long frame header or Long preamble) and second preamble (also known as long frame header or long preamble and short frame header), where the first preamble is used for 0LT registration discovery, ie

0NU enters the leading state used in the ranging state, ie, the 04 state; its length is longer than the length of the second preamble (bytes Bite), and is generally at least equal to or greater than 8 bits. The second preamble is used for normal communication or for the preamble used for normal uplink traffic transmission, that is, the preamble used when the 0NU is in the 05 state. The Allocation Structure further includes: an allocation identifier

Alloc-ID, 4 bits, used to identify the upstream bandwidth allocated by the 0LT to the 0NU; Flags Flags, 2 bits; Start Time, 16 bits; Bandwidth Grant Length, GrantSize, 16 bits; Power Management Indicator FWI, 1 bit; Hlend structure error detection and correction coding HEC, 13bits.

The specific use process is as follows:

For example, 0NU has recorded multiple burst (frame) templates Burst Profile during the online process, and saves the template after receiving the downlink frame sent by 0LT. The 0NU parses the downlink frame according to the downlink PL0AM message. For example, the ONU receives the PL0AM message "0 PP" as "00", indicating that the preamble (which may also be a preamble) is the first preamble, where the preamble is 32 bytes. The delimiter is 4 bytes; if the 0NU receives the PL0AM message "1 PP" is "01", it indicates that the preamble is the second preamble, the preamble is 4 bytes, and the delimiter is 4 bytes. After the OLT performs the active/standby switchover, the 0LT sets the Burst Profile to the first preamble in the downlink frame, and the ONU uses the uplink frame structure of the "00" defined by the PL0AM message, and uses the 32-byte uplink frame of the first preamble. Send it.

The embodiment of the present invention sets the Burst Profile field in the frame header of the downlink XGTC frame to the first preamble (long frame header), so that the ONU adopts the uplink frame of the first preamble, so that the 0LT receives the uplink burst frame sent by the ONU. According to the first preamble, the location of the uplink frame after the handover is determined, so that the EqD deviation of the ONU is obtained, and the re-ranging process of the ONU is implemented, which solves the problem that the POPUP message is not supported after the active/standby switchover in the current P0N system. , making 0LT and 0NU Interrupted data communication, increasing user satisfaction.

Step S310, 0LT detects that the at least one ONU transmits the uplink frame of the first preamble by using the second OLT, and obtains an equalization delay of the at least one optical network unit based on the uplink frame that includes the first preamble.

Step S312, the 0LT sends the equalization delay to the at least one optical network unit by using the second optical line terminal port, so that the at least one optical network unit is based on the equalization delay and the first The second optical line terminal P communicates. The 0LT obtains an equalization delay of the other optical network units in the multiple optical network units based on the equalization delay sent by the second optical line terminal port; and sends the equalization delay of the other optical network unit to the corresponding Said other optical network unit; or

The second is that the 0LT calculates the EqD deviation and sends it to the other ONUs in the optical network system through the second 0LT port in a broadcast manner, and the other ONUs respectively calculate the switched EqD according to the EqD deviation, and then based on the The switched EqD communicates with the 0LT through the second OLT port.

In the unicast mode, each 0NU EqD mode is sent, and the message returned by each 0NU can be used to confirm whether the active/standby switchover is successful.

In addition, when 0NU detects the TYPE B protection switching, it immediately clears the EqD value of the original P0N port and returns to the default value of 0. The distance measurement after the switching is consistent with the ranging processing flow when the 0NU is normally online.

The method for data communication in an optical network system provided by the embodiment of the present invention, after the communication between the authority end and the plurality of optical network units is switched from the first optical line terminal port to the second optical line terminal port, the second light is passed. Line terminal port Sending, to the at least one optical network unit, a downlink frame, where the downlink frame indicates that the at least one optical network unit sends the uplink frame by using the first preamble, where the length of the first preamble is greater than the length of the second preamble used for uplink service transmission Detecting, by the at least one optical network unit, an uplink frame that includes the first preamble sent by the second optical line terminal port, and obtaining an equalization time of the at least one optical network unit based on the uplink frame that includes the first preamble Transmitting, by the second optical line termination port, the equalization delay to the at least one optical network unit, so that the at least one optical network unit is based on the equalization delay and the second optical line termination The port communicates, so that the optical network system can perform the re-ranging state even if the POPUP message is not supported after the handover, thereby quickly recovering the data communication between the 0LT and the 0NU after the handover, thereby avoiding the impact on the normal service communication after the handover, and reducing The switching delay has improved the user's satisfaction, especially for the XGP0N system, which further solved the XGP. The problem of TYPE B active/standby switchover in the 0N system.

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

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

Step S602: After the communication between the authority end and the plurality of optical network units is switched from the first optical line terminal port to the second optical line terminal port, the 0LT sends a deactivation message or sends a redistribution message through the second optical line terminal port. The message identified by the optical network unit is provided to the at least one optical network unit such that the at least one optical network unit is offline.

Step S604: Perform re-ranging on the at least one optical network unit to obtain a first equalization delay of the at least one optical network unit.

Steps S606 and 0LT perform re-ranging on the optical network unit to obtain a first equalization delay of the optical network unit.

Steps S608, 0LT send the equalization delay to the at least one optical network unit by using the second optical line terminal port, so that the at least one optical network unit is based on the equalization delay and the second light. The line terminal port communicates.

The 0LT obtains an equalization delay of the other optical network units in the multiple optical network units based on the equalization delay sent by the second optical line terminal port; and sends the equalization delay of the other optical network unit to the corresponding Said other optical network unit; or

The 0LT obtains an equalization delay offset of the at least one optical network unit, and shifts the equalization time shift Sending the other optical network units of the multiple optical network units specifically includes two ways:

The method adopted on the user terminal side corresponding to the above method, that is, the 0NU side includes:

0NU performs offline according to the deactivation message;

After the 0NU re-measures, receiving the second equalization delay from the second optical line terminal port;

Another method for data communication in an optical network system according to an embodiment of the present invention, after the communication between the authority end and the plurality of optical network units is switched from the first optical line terminal port to the second optical line terminal port, the second The optical line terminal port sends a deactivation message or sends a message carrying the reassigned optical network unit identifier to the at least one optical network unit, such that the at least one optical network unit goes offline; re-ranging the at least one optical network unit Obtaining a first equalization delay of the at least one optical network unit; transmitting, by the second optical line termination port, the equalization delay to the at least one optical network unit, to enable the at least one optical network unit Performing communication with the second optical line terminal port based on the equalization delay, so that the optical network system can perform the re-ranging state even after the handover does not support the POPUP message, thereby quickly recovering the data between the 0LT and the ONU after the handover. Communication, avoiding the impact on normal service communication after switching, reducing the switching delay and improving the user's fullness Degree. As shown in FIG. 7, FIG. 7 is an optical network system according to an embodiment of the present invention. The system includes: a first optical line terminal port and a second optical line terminal port, where 0LT is connected through each optical line terminal port. 0NU;

The optical line terminal is further configured to generate an uplink bandwidth grant message, where the authorization message includes bandwidth information indicating the uplink frame and preamble template information, where the preamble template information indicates that the at least one optical network unit sends the uplink frame by using the first preamble. Encapsulating an upstream bandwidth grant message into the downstream frame.

The optical line terminal is further configured to obtain, according to the equalization delay sent by the second optical line terminal port, an equalization delay of the other optical network units in the multiple optical network units; and the other optical network unit The equalization delay is sent to the corresponding other optical network unit.

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

Also included between 0LT and 0NU is an optical distribution network 0DN, which includes: a backbone fiber and a branch fiber.

The embodiment of the present invention further provides another optical network system, where the system includes: a first optical line terminal port and a second optical line terminal port, where the optical line terminal connects the plurality of optical network units through each optical line terminal port;

The optical line terminal is configured to communicate from an optical line terminal and a plurality of optical network units from a first optical line terminal port After switching to the second optical line terminal port, sending a deactivation message through the second optical line terminal port or sending a message carrying the reassigned optical network unit identifier to the at least one optical network unit, so that the at least one optical network unit Performing re-ranging on the at least one optical network unit to obtain a first equalization delay of the at least one optical network unit; and transmitting, by the second optical line termination port, the equalization delay to the At least one optical network unit, such that the at least one optical network unit communicates with the second optical line termination port based on the equalization delay;

The method for data communication in an optical network system provided by the embodiment of the present invention, the system and the optical line terminal, after the communication between the authority end and the plurality of optical network units is switched from the first optical line terminal port to the second optical line terminal port, Sending, by the second optical line terminal port, a downlink frame to the at least one optical network unit, where the downlink frame indicates that the at least one optical network unit sends the uplink frame by using the first preamble, or sends a deactivation message or sends a bearer reassignment The message identified by the optical network unit is sent to at least one optical network unit, so that after the switching, the optical network system can perform the re-ranging state even if the POPUP message is not supported, thereby quickly recovering the data communication between the 0LT and the 0NU after the switching, thereby avoiding The impact on normal service communication after switching reduces the handover delay and improves user satisfaction.

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

a first sending unit 802, configured to: when the communication between the optical line terminal and the plurality of optical network units is switched from the first optical line terminal port to the second optical line terminal port, to the at least the second optical line terminal port An optical network unit sends a downlink frame, where the downlink frame indicates that the at least one optical network unit uses the first preamble to send an uplink frame, where the length of the first preamble is greater than the length of the second preamble used for uplink service transmission; The first obtaining unit 804 is configured to detect, by the at least one optical network unit, an uplink frame that includes the first preamble that is sent by using the second optical line terminal port, and obtain the at least the uplink frame that includes the first preamble. Equilibrium delay of an optical network unit;

a second sending unit 806, configured to send, by using the second optical line terminal port, an equalization delay of the at least one optical network unit to the at least one optical network unit, so that the at least one optical network unit is based on The equalization delay communicates with the second optical line termination port.

The optical line terminal further includes:

The bandwidth authorization unit 808 is connected to the first sending unit, and configured to generate an uplink bandwidth grant message, where the authorization message includes bandwidth information indicating the uplink frame and preamble template information, where the preamble template information indicates the at least one optical network unit The first preamble is used to send an uplink frame; and the uplink bandwidth grant message is encapsulated into the downlink frame.

The second obtaining unit 810 is configured to obtain, according to the equalization delay sent by the second optical line terminal port, an equalization delay of the other optical network units in the multiple optical network units.

The second sending unit is further configured to send the equalization delay of the other optical network unit to the corresponding other optical network unit.

The optical line terminal further includes:

The third obtaining unit 812 is configured to obtain, according to the equalization delay sent by the second optical line terminal port, an equalization delay offset of the at least one optical network unit.

The second sending unit is further configured to send the equalization time shift offset to other optical network units in the multiple optical network units.

The first receiving unit 902 is configured to perform communication according to the first equalization delay and the first optical line terminal port for communication; switch from the first optical line terminal port to the second optical line terminal port, and receive the second optical line. a downlink frame of the terminal port, where the downlink frame indicates that the uplink frame adopts a first preamble, where 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, to the second optical line terminal port, an uplink frame that includes the first preamble; the second receiving unit 906 is configured to receive a second equalization delay from the second optical line terminal port; The second equalization delay and the second optical line terminal port communicate for service transmission.

An optical line terminal according to an embodiment of the present invention, after the communication between the authority end and the plurality of optical network units is switched from the first optical line terminal port to the second optical line terminal port, the second optical line terminal port is at least An optical network The unit sends a downlink frame, where the downlink frame indicates that the at least one optical network unit uses the first preamble to send an uplink frame, where the length of the first preamble is greater than the length of the second preamble used for uplink service transmission; Obtaining an equalization delay of the at least one optical network unit based on the uplink frame that includes the first preamble by using an uplink frame that includes the first preamble sent by the second optical line terminal port; Transmitting, by the second optical line terminal port, the equalization delay to the at least one optical network unit, so that the at least one optical network unit communicates with the second optical line terminal port based on the equalization delay After the switchover, the optical network system can perform the re-range state even if the POPUP message is not supported, thereby quickly recovering the data communication between the 0LT and the 0NU after the handover, thereby avoiding the impact on the normal service communication after the handover, and reducing the handover delay. Improve user satisfaction, especially for XGP0N system, further solve the TYPE B master in XGP0N system Switching problem.

As shown in FIG. 10, the embodiment of the present invention further provides another optical line terminal, where the optical line terminal includes: a third sending unit 1002, configured to: when the optical line terminal and the plurality of optical network units communicate from After the first optical line terminal port is switched to the second optical line terminal port, sending, by the second optical line terminal port, a deactivation message or sending a message carrying the reassigned optical network unit identifier to the at least one optical network unit, so that Said at least one optical network unit is offline;

The fourth obtaining unit 1004 is configured to perform re-ranging on the at least one optical network unit to obtain a first equalization delay of the at least one optical network unit.

The fourth sending unit 1006 is configured to send, by using the second optical line terminal port, the equalization delay to the at least one optical network unit, so that the at least one optical network unit is based on the equalization delay and the The second optical line terminal port communicates.

The optical line terminal further includes:

The fifth obtaining unit 1008 is configured to obtain, according to the equalization delay sent by the second optical line terminal port, an equalization delay of the other optical network units in the multiple optical network units.

The fourth sending unit is further configured to send the equalization delay of the other optical network unit to the corresponding other optical network unit.

The optical line terminal according to claim 22, wherein the optical line terminal further comprises: a sixth obtaining unit 1010, configured to obtain, according to the equalization delay sent by the second optical line terminal port, Determining an equalization delay offset of at least one optical network unit;

The fourth sending unit is further configured to send the equalization delay offset to other optical network units in the multiple optical network units. According to another optical line terminal provided by the embodiment of the present invention, after communication between the authority end and the plurality of optical network units is switched from the first optical line terminal port to the second optical line terminal port, the second optical line terminal port is sent. Deactivating the message or sending a message carrying the redistributed optical network unit identifier to the at least one optical network unit, causing the at least one optical network unit to go offline; re-ranging the at least one optical network unit to obtain the at least a first equalization delay of an optical network unit; transmitting, by the second optical line termination port, the equalization delay to the at least one optical network unit, so that the at least one optical network unit is based on the equalization time The communication is performed with the second optical line terminal port, so that the optical network system can perform the re-ranging state even after the handover does not support the POPUP message, thereby quickly recovering the data communication between the 0LT and the ONU after the handover, thereby avoiding the handover. After the impact on normal business communication, the switching delay is reduced, and the user's satisfaction is improved.

A person skilled in the art can understand that all or part of the steps of implementing the above method embodiments may be completed by using hardware related to program instructions, and the foregoing program may be stored in a computer readable storage medium, and the program is executed when executed. The steps of the foregoing method embodiments are included; and the foregoing storage medium includes: various media that can store program codes, such as wake up, wake up, disk or optical disc.

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; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those skilled in the art that: The technical solutions described in the foregoing embodiments are modified, or some of the technical features are equivalently replaced; and the modifications or substitutions do not deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

Rights request

A communication method of an optical network system, wherein a central end 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, wherein The method includes: after the communication between the authority end and the plurality of optical network units is switched from the first optical line termination port to the second optical line termination port, sending, by the second optical line termination port, the downlink frame to the at least one optical network unit, where The downlink frame indicates that the at least one optical network unit sends the uplink frame by using the first preamble, wherein the length of the first preamble is greater than the length of the second preamble for uplink traffic transmission;

2. The method according to claim 1, before the sending the downlink frame, the method further includes: generating an uplink bandwidth grant message, where the authorization message includes bandwidth information indicating the uplink frame and preamble template information, where the preamble template information indicates the at least one The optical network unit sends the uplink frame by using the first preamble;

Encapsulating an upstream bandwidth grant message into the downstream frame.

The method according to claim 1 or 2, wherein the method further comprises:

And obtaining, according to the equalization delay sent by the second optical line terminal port, an equalization delay of the other optical network units in the multiple optical network units;

And transmitting the equalization delay of the other optical network unit to the corresponding other optical network unit.

The method according to claim 1 or 2, wherein the method further comprises:

Obtaining an equalization delay offset of the at least one optical network unit based on the equalization delay sent by the second optical line terminal port, and transmitting the equalization time shift offset to other opticals in the multiple optical network units Network unit.

5. A communication method for an optical network system, the method comprising:

Receiving a second equalization delay from the second optical line terminal port; And performing traffic transmission based on the second equalization delay and the second optical line terminal port communication.

A communication method of an optical network system, wherein a central end 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, wherein , the method includes:

After the communication between the authority and the plurality of optical network units is switched from the first optical line terminal port to the second optical line terminal port, the deactivation message is sent through the second optical line terminal port or the optical network unit identifier carrying the reassignment is sent. Message to at least one optical network unit, causing the at least one optical network unit to go offline;

The method according to claim 6, wherein the method further comprises:

A communication method for an optical network system, the method comprising:

Switching from the first optical line termination port to the second optical line termination port, receiving a deactivation message from the second optical line termination port or carrying a message of the reassigned optical network unit identity;

Performing offline according to the deactivation message;

An optical network system, comprising: a first optical line terminal port and a second optical path terminal port, wherein the optical line terminal connects the plurality of optical network units through each optical line terminal port;

The optical line terminal is configured to: when the communication between the optical line terminal and the plurality of optical network units is switched from the first optical line terminal port to the second optical line terminal port, to the at least one light through the second optical line terminal port Network unit sending a downlink frame, the downlink frame instructing the at least one optical network unit to transmit an uplink frame by using a first preamble, wherein a length of the first preamble is greater than a length of a second preamble for uplink traffic transmission; and detecting the at least one light Obtaining an equalization delay of the at least one optical network unit based on the uplink frame including the first preamble by using the uplink frame that includes the first preamble sent by the second optical line terminal port; The optical line termination port transmits the equalization delay to the at least one optical network unit to cause the at least one optical network unit to communicate with the second optical line termination port based on the equalization delay.

The optical network system according to claim 10, wherein the optical line terminal is further configured to generate an uplink bandwidth grant message, where the authorization message includes bandwidth information indicating the uplink frame and preamble template information, and the preamble The template information indicates that the at least one optical network unit sends the uplink frame by using the first preamble; and the uplink bandwidth grant message is encapsulated into the downlink frame.

The optical network system according to claim 10 or 11, wherein the optical line terminal is further configured to obtain the multiple optical networks based on an equalization delay sent by the second optical line terminal port. Equalization delay of other optical network units in the unit; transmitting the equalization delay of the other optical network units to the corresponding other optical network unit.

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 based on an equalization delay sent by the second optical line terminal port. An equalization delay offset of the unit, the equalization time shift offset being transmitted to other optical network units of the plurality of optical network units.

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 the plurality of optical network units is switched from the first optical line terminal port to the second optical line terminal port Or sending a message carrying the redistributed optical network unit identifier to the at least one optical network unit, causing the at least one optical network unit to go offline; re-ranging the at least one optical network unit to obtain the at least one optical network a first equalization delay of the unit; transmitting, by the second optical line termination port, the equalization delay to the at least one optical network And causing the at least one optical network unit to communicate with the second optical line terminal port based on the equalization delay;

The optical network system according to claim 14, wherein the optical line terminal is further configured to obtain, according to the equalization delay sent by the second optical line terminal port, the plurality of optical network units. Equalization delay of other optical network units; transmitting the equalization delay of the other optical network units to the corresponding other optical network unit.

The optical network system according to claim 14, wherein the optical line terminal is further configured to obtain, according to the equalization delay sent by the second optical line terminal port, the at least one optical network unit. Equalizing the delay offset, transmitting the equalization time shift to other optical network units in the plurality of optical network units.

17. An optical line terminal, wherein the optical line terminal comprises:

a first acquiring unit, configured to detect an uplink frame that includes the first preamble sent by the at least one optical network unit by using the second optical line terminal port; and obtain the at least one uplink based on the uplink frame that includes the first preamble Equilibrium delay of the optical network unit;

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 grant message, where the authorization message includes And indicating the bandwidth information of the uplink frame and the preamble template information, where the preamble template information indicates that the at least one optical network unit sends the uplink frame by using the first preamble; and the uplink bandwidth grant message is encapsulated into the downlink frame.

The optical line terminal according to claim 17 or 18, wherein the optical line terminal further comprises: a second acquiring unit, configured to obtain, according to the equalization delay sent by the second optical line terminal port, an equalization delay of other optical network units in the multiple optical network units;

The optical line terminal according to claim 17 or 18, wherein the optical line terminal further comprises: a third obtaining unit, configured to obtain, according to the equalization delay sent by the second optical line terminal port, An equalization delay offset of the at least one optical network unit;

An optical network unit, where the optical network unit includes:

a receiving unit, configured to perform communication according to the first equalization delay and the first optical line terminal port to perform service transmission; switch from the first optical line terminal port to the second optical line terminal port, and receive the second optical line terminal port a downlink frame, where the downlink frame indicates that the uplink frame adopts a first preamble, where a length of the first preamble is greater than a length of a second preamble used for uplink service transmission;

a fifth sending unit, configured to send, to the second optical line terminal port, an uplink frame that includes the first preamble; and a second receiving unit, configured to receive a second equalization delay from the second optical line terminal port; The second equalization delay communicates with the second optical line terminal port for service transmission.

An optical line terminal, wherein the optical line terminal comprises:

a third sending unit, configured to send, by the second optical line terminal port, deactivation after communication between the optical line terminal and the plurality of optical network units is switched from the first optical line terminal port to the second optical line terminal port Sending, by the message, a message carrying the reassigned optical network unit identifier to the at least one optical network unit, such that the at least one optical network unit is offline;

The optical line terminal according to claim 22, wherein the optical line terminal further comprises: a fifth obtaining unit, configured to obtain the balance based on an equalization delay sent by the second optical line terminal port Multiple lights Equilibrium delay of other optical network units in the network unit;

The optical line terminal according to claim 22, wherein the optical line terminal further comprises: a sixth obtaining unit, configured to obtain the balance based on an equalization delay sent by the second optical line terminal port Equilibrium delay offset of at least one optical network unit;

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