WO2011094990A1

WO2011094990A1 - Method and system for path switching and method for transmitting downlink data

Info

Publication number: WO2011094990A1
Application number: PCT/CN2010/074427
Authority: WO
Inventors: 张伟良; 张德智; 耿丹
Original assignee: 中兴通讯股份有限公司
Priority date: 2010-02-05
Filing date: 2010-06-24
Publication date: 2011-08-11
Also published as: CN102149027A; CN102149027B

Abstract

A method and system for path switching and a method for transmitting downlink data are provided by the present invention. The method for path switching includes: a current working optical line terminal (OLT) transmits downlink data carrying the identity information of the OLT itself to an optical network unit (ONU); the ONU receives and parses the downlink data in order to obtain the identity information of the current working OLT; and when a change in the identity information of the current working OLT is detected by the ONU, the ONU performs path switching. The ONU skips some existing login and activation steps in order to reduce the time of switchover from primary path to a backup path performed by the OLT and the ONU, and improve the communication efficiency between the OLT and the ONU.

Description

Path switching method, system and downlink data transmitting method

The present invention relates to passive optical network technologies, and in particular, to a path switching method, a system, and a downlink data sending method in a passive optical network. Background technique

Gigabit-Capable Passive Optical Network (GPON) technology is an important technology branch of the Passive Optical Network (PON) family. Similar to other PON technologies, GPON is also a point-to-multipoint topology. Structured passive optical access technology.

1 is a schematic diagram of a topology of an existing GPON system. As shown in FIG. 1, the GPON is composed of an optical line terminal (OLT, Optical Line Terminal) on the central office, an optical network unit (ONU), and an optical network unit (ONU). The ODN (Optical Distribution Network) is usually composed of a point-to-multipoint network structure. The ODN consists of passive optical components such as single-mode fiber, optical splitter, and optical connector, providing an optical transmission medium for the physical connection between the OLT and the ONU.

In the GPON system, the data transmission in the downlink direction (from the OLT to the ONU) is broadcast, and each ONU receives all the frames, and then according to the ONU identifier (ONU-ID), the GEM port identifier (GEM-Port ID), and the configuration. Identifies (Allocation-ID) to get the frame of my own. For data transmission in the upstream direction (from ONU to OLT), since each ONU needs to share the transmission medium, each ONU should arrange uplink data in its own time slot arranged by the OLT.

2 is a schematic diagram of a downlink frame structure of a GPON (G-PON Transmission Convergence) layer. As shown in FIG. 2, a downlink frame of a GPON is a Physical Control Block downstream (PCBd) and a payload. Two parts, wherein PCBd consists of Psync (Physical Synchronization), Ident (Ident) domain, downlink physical layer operation, management and maintenance (PLOAMd, Physical Layer Operation, The Administraion and Maintenance downstream domain consists of a Bit Interleaved Parity (BIP), a Plend (payload Length downstream), and an Upstream Bandwidth Map (US BWmap).

In a passive optical network deployment, if a staff installs an ONU in a PON system as shown in Figure 1, in some scenarios, the OLT and the ONU may be far apart, up to several tens of kilometers. According to the current GPON protocol, the OLT sends (as shown in Figure 2) the downlink frame does not contain the OLT feature information. However, when the staff installs the ONU at the branch fiber access point, the OLT port information corresponding to the point needs to be obtained. To ensure that the ONU is installed in the correct PON system. If the ONU is not installed in the ODN to which the correct OLT belongs, the installed ONU may not work properly.

In addition, in the deployment of passive optical networks, some users need higher security. It is hoped that operators can provide a guarantee mechanism to ensure that their service channels are not interrupted, or the next level of requirements is that they can be in the service. Quick recovery after the channel is interrupted. This puts forward the requirements for protection paths and fast switching paths for passive optical networks carrying user services.

Figure 3 shows a typical network architecture in the protection mode of the existing passive optical network standard. Figure 4 is a schematic diagram of another typical network architecture in the protection mode in the existing passive optical network standard.

Figure 3 shows the manner in which Type B protects the backbone fiber. As shown in Figure 3, the two optical ports of the OLT, namely the passive optical network line terminal optical port 0 (PON LT(O)) and port 1 (PON LT(l)) are connected to a 2:N splitter. The downstream direction of the optical splitter is respectively connected to each ONU through optical fibers (the number is from N1 to #N). It is assumed that the optical port PON LT(0) of the OLT passes through the optical splitter to the path of the ONU as the primary path, and the optical port PON LT(1) of the OLT passes through the optical splitter to the ONU as the standby path. After the primary path is interrupted as the service path of the optical network unit and the optical line terminal, the alternate path is enabled as the service path of the optical network unit and the optical line terminal to maintain communication between the optical network unit and the optical line terminal. Figure 4 shows the all-fiber protection of Type C. As shown in FIG. 4, the optical port PON LT(0) of the OLT is connected to the 1:N splitter 1, and the optical port PON LT(l) of the OLT is connected to the 1:N splitter 2, and the two splitters respectively pass The fiber is connected to each ONU. It is assumed that the optical port PON LT(O) of the OLT reaches the path of the ONU through the optical splitter 1 as the primary path, and the path of the optical port PON LT(1) of the OLT to the ONU through the optical splitter 2 is the standby path. After the primary path is interrupted as the service path of the optical network unit and the optical line terminal, the alternate path is enabled as the service path of the optical network unit and the optical line terminal to maintain communication between the optical network unit and the optical line terminal.

In the existing protection mode of the passive optical network shown in FIG. 3 and FIG. 4, the process of enabling the alternate path after the primary path failure is taken as an example to illustrate the logical state transition process of the optical network unit.

Figure 5 is a schematic diagram of the logical state transition process of the optical network unit when the standby path is enabled after the failure of the existing primary path. As shown in Figure 5, it is assumed that the ONU and the OLT pass the primary path between the two, that is, PON LT (O The channel communication of the port, the ONU is in the running state (05); after the main channel is interrupted, it includes:

The ONU does not detect the optical signal of the OLT in the primary path, generates a loss of synchronization (LOS/LOF) alarm, and enters a pop-up state (06). After the ONU is in the pop-up state (06) for longer than the time set by the T02 timer, Enter the initial state (01);

The OLT enables the alternate path, that is, the path of the PON LT(1) port, synchronizes the alternate channel related protocol configuration parameters (such as the transmitted optical power, the ONU ID, the T-CONT ID, the GEM ID, etc.), and sends the downlink optical signal to the ONU, and the ONU. Perform frame delimitation and synchronization;

After detecting the downlink optical signal of the OLT, the ONU cancels the LOS/LOF alarm of the OLT, and after the frame is delimited and synchronized by the standby path and the OLT, the ONU transitions from the initial state (01) to the standby state (02);

After receiving the uplink overhead parameter sent by the OLT, the ONU transits from the standby state ( 02 ) to the sequence number state ( 03 ); the uplink overhead parameter includes: a preamble bit type, a delimiter parameter, and a delimiter parameter. After the OLT switches from the primary path to the standby path, the ID of the ONU to be managed is reassigned, and the ID of each re-allocated ONU is sent to each ONU. After receiving the ONU-ID information sent by the OLT, the ONU receives the information from the OLT. The serial number status (03) is transferred to the ranging state (04);

After receiving the EqD (Equalization Delay) message sent by the OLT, the ONU transits from the ranging state (04) to the running state (05);

At this point, the alternate path between the ONU and the OLT is completely established, and the ONU interacts with the OLT through the alternate path.

In the path switching process shown in Figure 5, after the physical layer path is established on the alternate path, the OLT needs to send EqD and other related data to all ONUs. Each ONU needs to update its own parameters after receiving the relevant data, and the alternate path is The adjustment of the transmit power is completed between the OLT optical ports, and finally the normal working state can be restored. Taking the network structure of type B shown in Figure 3 as an example, when there are 32 ONUs managed by a 0LT, in the path switching process, 0LT needs to interact with 32 ONUs and complete the state as shown in Figure 5. Migration process (ie experiencing 01, 02, 03, 04 and 05). It can be seen that the existing path switching process has the following problems:

(1) Each 0NU completes the above series of state transitions, so that 0LT has to bear a lot of messaging work;

(2) During processing, due to the limited capacity of the path between 0LT and ONU, there is not enough capacity in the GTC downstream frame to store the Physical Layer Operation Administration and Maintenance (PLOAM) message to support 32 0NU also completes the foregoing state transition process. Therefore, most of the 0NUs need to wait for messages, which prolongs the path switching time, affects the 0NU and 0LT to quickly resume normal communication, and restores 0NU and 0LT to normal operation. The basic time is on the order of 100 milliseconds. The above, can not meet the user's requirements for rapid recovery of network failures. Summary of the invention

In view of this, the main object of the present invention is to provide a path switching method and system in a passive optical network, which can shorten the time of path switching and quickly realize the recovery of normal communication between the ONU and the OLT.

Another object of the present invention is to provide a method for transmitting downlink data in a passive optical network, which ensures that the ONU is installed in the ODN to which the correct OLT belongs, and ensures normal operation of the ONU.

In order to achieve the above object, the technical solution of the present invention is achieved as follows:

A path switching method includes:

The current working optical line terminal OLT sends downlink data carrying the identity information of the OLT to the optical network unit ONU;

The ONU receives and parses the downlink data to obtain identity information of the current working OLT. When the ONU detects that the identity information of the current working OLT changes, the ONU performs path switching.

When the ONU detects that the identity information of the current working OLT changes, the ONU performs the path switching, including:

When the ONU detects that the identity information of the current working OLT changes, the ONU configures its working parameters as an alternate path according to the correspondence between the identity information of the OLT and the working parameters of the ONU on the standby path. After entering the working parameters, the working parameters.

The current working OLT sends the downlink data carrying the identity information of the OLT to the ONU, including:

When the primary path is used as the working path, the OLT on the primary path sends the downlink data carrying the identity information of the OLT to the ONU; when the primary path is invalid, the standby path acts as the working path, and the OLT on the working path sends the carrying to the ONU. There is downlink data of the identity information of the OLT.

The ONU receives identity information from the OLT when in the following state: a standby state; or, transitions from a standby state to a sequence number state, and is in a sequence number state; or, from The standby state shifts to the serial number state, and then shifts from the serial number state to the ranging state, and is in the ranging state.

The ONU stores the correspondence between the identity information of the OLT on the alternate path and the working parameters of the ONU on the standby path in the following manner:

When the primary path is used as the working path, the OLT on the standby path sends its own identity information to the OLT on the primary path, and performs measurement of the operating parameters of all ONUs on the standby path through the OLT on the primary path;

The OLT on the primary path sends the identity information of the OLT on the received standby path and the measured working parameters of the measured ONU on the standby path to the corresponding ONU;

The ONU receives the identity information of the OLT and the working parameters of the ONU on the standby path that are sent by the OLT on the primary path, and stores the correspondence between the identity information and the working parameter.

The ONU stores the identity information of the OLT on the alternate path and the working parameters of the ONU on the alternate path, and the corresponding relationship between the two is the system default setting.

The OLT sends the downlink data carrying the identity information of the OLT by: carrying the identity information in a newly added domain in a downlink frame, where the newly added domain is located in a downlink of a downlink frame of the GPON Physical control block in the PCBd domain, or in the GEM header of the payload of the downstream frame of the GPON;

Or the identity information is carried in an existing domain in a downlink frame, where the existing domain is a downlink physical layer OAM PLOAMd domain, or a payload domain.

The identity information of the OLT includes one or any combination of the following: a country where the OLT is located, a city where the OLT is located, OLT identification information, slot identification information of the OLT, port identification information currently working by the OLT, and information about the transmitted optical power of the OLT. Or, The logical information that has a preset correspondence with the identity information of the actual OLT.

A path switching system, including an optical line terminal OLT and an optical network unit ONU; when the path is used as a working path, the OLT on the working path is configured to send downlink data carrying the identity information of the OLT to the ONU;

The ONU is configured to store the correspondence between the identity information of the OLT on the standby path and the working parameters of the ONU on the standby path when the primary path is normally communicating; and is further configured to receive and parse the downlink data to obtain the current work. The identity information of the OLT is used, and when the identity information of the current working OLT is detected, the working parameter is configured as the working parameter of the standby path according to the corresponding relationship stored by the OLT, and then enters the working state.

When the main path is used as a working path,

The OLT on the standby path is configured to send its own identity information to the OLT on the primary path;

The OLT on the primary path is used to complete the measurement of the working parameters of all the ONUs on the standby path, and send the identity information of the OLT on the received standby path and the measured working parameters of the measured ONU on the standby path. Give the corresponding ONU;

The ONU is configured to receive the identity information of the OLT on the standby path sent by the OLT on the primary path and the working parameter of the ONU on the standby path, and then store the correspondence between the identity information and the working parameter; or The ONU stores the identity information of the OLT on the standby path and the working parameters of the ONU on the standby path, and the corresponding relationship between the two is a system default setting.

A method for transmitting downlink data includes:

The ONU receives and parses the downlink data, obtains identity information of the current working OLT, and performs Display.

The identity information of the OLT includes one or any combination of the following: a country where the OLT is located, a city where the OLT is located, OLT identification information, slot identification information of the OLT, port identification information currently working by the OLT, and information about the transmitted optical power of the OLT. Or,

The logical information that has a preset correspondence with the identity information of the actual OLT.

The ONU is a handheld terminal with a display.

The ONU displays the identity information of the OLT through a network management.

It can be seen from the technical solution provided by the present invention that the method and system for implementing path switching by the present invention, the OLT and the ONU quickly transfer to the standby path after the failure of the primary path, and the ONU skips the existing registration activation step. The time required for the conversion of the OLT and the ONU from the primary path to the alternate path is reduced, and the communication efficiency between the OLT and the ONU is improved. In the method for transmitting downlink data of the present invention, the OLT sends downlink data carrying the identity information of the OLT to the ONU, and the ONU receives the downlink data, and can identify and display the identity information of the current working OLT, thereby ensuring that the ONU is installed correctly. In the PON, the normal installation of the ONU is guaranteed. DRAWINGS

1 is a schematic diagram of a topology of an existing GPON system;

2 is a schematic diagram of a downlink frame structure of a GTC layer of an existing GPON;

Figure 3 is a schematic diagram of a typical network architecture in the protection mode in the existing passive optical network standard; 4 is a schematic diagram of another typical network architecture in the protection mode in the existing passive optical network standard;

FIG. 5 is a schematic diagram of a logical state transition process of an optical network unit when an alternate path is enabled after an existing primary path fails;

6 is a schematic diagram of a downlink frame structure of a GTC layer of a GPON according to the present invention;

FIG. 7 is a flow chart of implementing path switching according to the present invention. detailed description

The downlink data sending method of the present invention includes: the OLT sends downlink data carrying the identity information of the OLT to the ONU, and the ONU receives and parses the downlink data, obtains the identity information of the current working OLT, and displays the information. Among them, the identity information of the OLT can be carried in the following manner:

In the first mode, the identity information of the OLT is carried in a newly added domain in the downlink frame. The newly added domain may be located in the PCBd domain of the GPON downlink frame or in the GEM frame header of the payload of the GPON downlink frame. For example, adding a domain in the PCBd field of the GPON downlink frame to carry the identity information of the OLT that transmits the downlink frame is an example. FIG. 6 is a schematic diagram of a downlink frame structure of the GTC layer of the GPON according to the present invention.

As shown in FIG. 6, the PON identification information (PON-ID, PON identifier) field is included in the PCBd domain of the downstream frame of the GPON, and the PON-ID field is located between the Psync domain and the Ident domain (FIG. 6 is only for the PON-ID). The location gives an example, and the PON-ID can also be located elsewhere in the PCBd domain). The PON-ID field is used to carry the identity information of the OLT (ie, PON-ID information), including one or any combination of the following: the country where the OLT is located (Country), the city where the OLT is located (City), and the OLT identification information (OLT-ID) ), the slot identification information (Slot-ID) of the OLT, the port identification information (Port-ID) at which the OLT is currently working, and the transmitted optical power information (Power) of the OLT. Of course, the identity information used by the PON-ID domain to carry the OLT may also be logical information, that is, a code or code that has a preset correspondence with the actual information.

In this way, in the deployment application of GPON, when the staff needs to install an ONU to In the GPON system, the worker selects a GPON access node and connects a device that can receive the GP0N downlink frame (for example, a handheld terminal with a display) to the access node to receive the downlink frame, and the staff receives the data according to the reception. The information of the PON-ID field in the downlink frame to which it is determined determines whether the currently used access node belongs to the PON to be accessed by the ONU, thereby ensuring that the ONU is installed in the correct PON. Further, after receiving the transmitted optical power information of the OLT in the PON-ID domain, the ONU compares with the OLT optical power received by the ONU itself to calculate the link loss of the PON system.

Manner 2: The identity information of the OLT is carried in an existing domain in a downlink frame, such as in a PLOAMd domain (or PLOAM message), or in a payload. among them,

The PLOAM message carrying the identity information of the OLT is referred to herein as a PON-ID message, and the format of the PON-ID message is as shown in Table 1.

Table 1

As shown in Table 1, the first byte of the PON-ID message is the value of the ONU-ID, and the content of the byte is 11111111, indicating that the message is broadcast to all ONUs; the content of the byte is 11111110, indicating to all The registered ONU broadcasts the message; when the content of the byte is the ONU-ID 1 other than 11111111 and 11111110, the message is sent to the ONU whose ONU-ID value is ONU-ID1. The content of the second byte of the PON-ID message indicates that the type of the PLOAM message is the PON identification information type.

The contents of the third to twelfth bytes of the PON-ID message are the identity information of the OLT, including: the country where the OLT is located, the city where the OLT is located, the OLT-ID, the Slot-ID, the Port-ID, and the transmitted optical power information of the OLT. .

The OLT may send the broadcast PON-ID message in a certain period; or, after receiving the PON-ID request message sent by an ONU, the OLT sends a PON-ID message to the ONU that sends the PON-ID request. The format of the PON-ID request message sent by the ONU is shown in Table 2.

Table 2

As shown in Table 2, the first byte of the PON-ID request message is the value of the ONU-ID, indicating that the message is from the ONU whose ONU-ID value is ONU-ID 1.

The content of the second byte of the PON-ID request message indicates that the type of the PLOAM message is the PON-ID request type.

The identity information of the OLT may also be carried by the newly created OMCI message, and the OMCI message carrying the identity information of the OLT is referred to herein as a PON-ID message. The OMCI message may include a Message type field and a Message contents field. The message type field includes a PON-ID message for indicating that the message is the identity information of the OLT, for example, bit 1 to bit 5. The message content field is used to carry the identity information of the OLT, including: the country where the OLT is located, and the OLT. City, OLT-ID, Slot-ID, Port-ID, OLT transmit optical power information. The value of the port identifier (Port-ID) in the GEM header of the GEM frame encapsulating the OMCI It can be set to 11111110, indicating that the type of OMCI message encapsulated by the GEM frame is a PON-ID message.

The OLT can send the OMCI message with the message type PON-ID in a certain period. After receiving the PON-ID type OMCI message sent by the OLT, the ONU obtains the identity information of the OLT that sends the message according to the message content field of the OMCI message.

After the PON-ID message sent by the OLT is received by the ONU, the ONU compares with the OLT optical power received by the ONU according to the received optical power information of the OLT in the PON-ID message, and calculates the PON system link. loss.

In the PON protection structure of type B and type C in the prior art, the path currently in operation is called the primary path, and after the failure of the primary path, the OLT (and ONU) switches to the alternate path. FIG. 7 is a flowchart of implementing path switching according to the present invention. As shown in FIG. 7, the method includes the following steps: Step 700: When the primary path is used as the working path for normal communication, the OLT on the primary path is sent by using the foregoing mode 1 or mode 2. The downlink data of the identity information is sent to the ONU, and the ONU receives and parses the downlink data to obtain the identity of the current working OLT. The ONU stores the correspondence between the PON identity information of the OLT of the standby path and the working parameters of the ONU in the standby path.

This step generally includes: when the primary path is used as the working path, the OLT on the standby path sends its own identity information to the OLT on the primary path, and the OLT on the standby path completes all ONUs through the OLT on the primary path. Measurement of the working parameters on the alternate path; the OLT on the primary path sends the identity information of the OLT on the alternate path and the operating parameters of the ONU on the alternate path to all ONUs through the newly created PLOAM message or GEM frame; After receiving the foregoing information sent by the OLT on the primary path, the ONU stores the correspondence between the identity information of the OLT on the standby path and the working parameters of the ONU on the standby path; or

The ONU stores the identity information of the OLT on the standby path and the working parameters of the ONU on the standby path, and the corresponding relationship between the two is the system default setting. This step emphasizes that, regardless of the method, the ONU stores the identity information PON-ID and ONU of the OLT on the alternate path. Correspondence of operating parameters on the alternate path.

The working parameters of the primary path and the alternate path stored in the ONU in this step include the OLT identity information of the two paths, that is, the PON-ID information, the preamble bit type, the delimiter parameter (Delimiter), and the ONU transmission optical power level parameter. , EqD, Equalization Delay, and the ONU ID assigned to it by the two OLTs. The PON-ID information includes the country where the OLT is located, the city where the OLT is located, the OLT identification information (OLT-ID), the slot identification information of the OLT (Slot-ID), and the identification information (Port-ID) of the current working port of the OLT. The OLT transmits the optical power information, and the ONU identifies the identity of the OLT in the working state according to the PON-ID information sent by the OLT, and configures the above working parameters according to the received PON-ID information of the OLT to establish and work between the OLTs. Communication.

Step 701: After the primary path is invalid, the ONU synchronizes with the OLT on the standby path.

After the primary channel for data communication between the ONU and the OLT is invalid, the ONU generates a loss of synchronization (LOS/LOF) alarm and enters the pop-up state (06). The ONU is in the pop-up state (06) for longer than the preset duration of the T02 timer. After that, enter the initial state (01). The OLT enables the alternate path to send the downlink frame, the ONU completes synchronization with the OLT, and the ONU enters the 02 state.

Step 702: The standby path is used as the working path, and the OLT on the standby path sends the downlink data carrying the identity information (PON-ID) to the ONU by using mode 1 or mode 2, and the ONU receives and parses the downlink data, and according to the PON in the downlink data. The -ID information gets the identity of the current working OLT. After the ONU finds that the identity information of the OLT is changed, the ONU configures its working parameters as the working parameters of the standby path according to the corresponding relationship between the OLT identity information stored in the alternate path and the ONU in the standby path working parameter, and then enters the working state. .

By implementing the path switching method by the present invention, the OLT and the ONU quickly transfer to the standby path after the primary path fails, and the ONU skips the existing registration activation step from the 02 state to the 05 state, thereby minimizing the OLT and the The time required for the ONU to transition from the primary path to the alternate path maximizes communication efficiency between the OLT and the ONU. The specific implementation of the step 702 may be: the ONU is transferred from the 02 state to the 03 state according to the existing method; and the ONU in the 03 state receives the downlink frame or the PON-ID message sent by the OLT in the mode 1 or mode 2, according to the downlink frame or The PON-ID content carried in the PON-ID message obtains the identity information of the current working OLT, and the ONU configures its own working parameter as the work of the standby path according to the correspondence between the stored PON-ID of the alternate path and the working parameters of the alternate path. Parameters, ONU enters the working state. It can be seen that after the primary path fails, the OLT and the ONU quickly transfer to the standby path. The ONU skips the existing registration activation step from the 03 state to the 05 state, reducing the conversion of the OLT and the ONU from the primary path to the alternate path. The time required to improve communication efficiency between the OLT and the ONU.

The specific implementation of the step 702 may be: the ONU shifts from the 02 state to the 03 state according to the existing method, and then shifts from the 03 state to the 04 state; the ONU of the 04 state receives the downlink frame or PON sent by the OLT in the first mode or the second mode. After the ID message, the identity information of the current working OLT is obtained according to the PON-ID content carried in the downlink frame or the PON-ID message, and the ONU is configured according to the correspondence between the stored PON-ID of the alternate path and the working parameters of the standby path. The working parameters of the slave are the working parameters of the standby path, and the ONU enters the working state. It can be seen that after the primary path fails, the OLT and the ONU quickly transfer to the standby path, and the ONU skips the existing registration activation step from the 04 state to the 05 state, thereby reducing the conversion of the OLT and the ONU from the primary path to the alternate path. The required time increases the communication efficiency between the OLT and the ONU.

For the path switching method of FIG. 7 of the present invention, a path switching system is further provided, including 0LT and 0NU, wherein

0LT includes 0LT on the primary path and 0LT on the alternate path. When the primary path or the alternate path is used as the working path, the 0LT of the working path is used to send downlink data carrying the identity information of the 0LT to the 0NU;

The ONU is used to store the correspondence between the identity information of the OLT on the standby path and the working parameters of the ONU on the standby path when the primary path is normally communicating; and is also used to receive and parse the downlink number. According to the method, the identity information of the current working OLT is obtained; and when the identity information of the current working OLT is detected, the working parameter is configured as the working parameter of the standby path according to the corresponding relationship stored by the OLT, and then enters the working state.

The ONU receives the PON-ID content sent by the OLT when it is in the 02 state or the 03 state or the 04 state, and obtains the identity information of the current working OLT. The ONU is based on the correspondence between the stored PON-ID of the alternate path and the working parameters of the standby path. Configure its own working parameters as the working parameters of the alternate path, and the ONU enters the working state.

When the primary path is used as the working path, the OLT on the standby path is used to transmit its own identity information to the OLT on the primary path; the OLT on the primary path is used to complete the measurement of the operating parameters of all ONUs on the alternate path. And transmitting the identity information of the OLT on the received standby path and the measured working parameters of the ONU on the standby path to the corresponding ONU; the ONU is configured to receive the OLT on the alternate path sent by the OLT on the active path. The identity information and the ONU store the corresponding relationship between the identity information and the working parameters after the working parameters on the standby path;

Alternatively, the ONU stores the identity information of the OLT on the alternate path and the operating parameters of the ONU on the alternate path, and the corresponding relationship between the two is the system default setting.

It should be noted that the PON-ID content transmitted in the downlink frame proposed by the present invention may be protected by forward error correction (FEC, Forward Error Correction) coding, or may not be within the range of FEC coding.

The downlink data transmission method including the PON-ID content proposed by the present invention is also applicable to a GPON-based next generation PON system.

The above description is only for the preferred embodiment of the present invention, and is not intended to limit the scope of the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included. Within the scope of protection of the present invention.

Claims

Claim

A method for switching a path, comprising:

The path switching method according to claim 1, wherein when the ONU detects that the identity information of the current working OLT changes, the ONU performs the path switching, where the ONU detects the identity information of the current working OLT. When a change occurs, the operating parameters of the OLT are stored in the working state according to the working parameters of the OLT and the working parameters of the ONU on the standby path.

The path switching method according to claim 1, wherein the current working OLT sends the downlink data carrying the identity information of the OLT to the ONU, including:

The path switching method according to claim 1, wherein the ONU receives identity information from the OLT when in the following state: a standby state; or, shifts from a standby state to a serial number state, and In the serial number state; or, from the standby state to the serial number state, and then from the serial number state to the ranging state, and in the ranging state.

The path switching method according to claim 2, wherein the ONU stores the correspondence between the identity information of the OLT on the standby path and the working parameters of the ONU on the standby path in the following manner:

When the primary path is used as the working path, the OLT on the alternate path sends its own identity information. Giving the OLT on the primary path and measuring the operating parameters of all ONUs on the alternate path through the OLT on the primary path;

The path switching method according to any one of claims 1 to 6, wherein the OLT transmits downlink data carrying the identity information of the OLT by:

Carrying the identity information in a newly added domain in the downlink frame, where the newly added domain is located in the downlink physical control block PCBd domain of the GPON downlink frame, or the GEM frame of the payload of the downlink frame of the GPON In the head

The path switching method according to any one of claims 1 to 6, wherein the identity information of the OLT includes one or any combination of the following: a country where the OLT is located, a city where the OLT is located, and OLT identification information. The slot identification information of the OLT, the port identification information currently working by the OLT, and the transmitted optical power information of the OLT; or

9. A path switching system, comprising: an optical line terminal OLT and an optical network When the path is used as the working path, the OLT on the working path is used to send downlink data carrying the identity information of the OLT to the ONU;

10. The path switching system according to claim 9, wherein when the main path is used as a working path,

11. A method for transmitting downlink data, characterized in that:

The downlink data sending method according to claim 11, wherein the OLT sends downlink data carrying the identity information of the OLT by:

The method for transmitting downlink data according to claim 11, wherein the identity information of the OLT includes one or any combination of the following: a country where the OLT is located, a city where the OLT is located, an OLT identification information, and a slot of the OLT. Bit identification information, port identification information currently working by the OLT, and transmitted optical power information of the OLT; or

The downlink data transmitting method according to claim 11, wherein the ONU is a handheld terminal with a display screen.

The method for transmitting downlink data according to claim 11, wherein the ONU displays the identity information of the OLT through a network management.