WO2012068894A1

WO2012068894A1 - System and method for implementing remote disaster recovery of optical line terminal

Info

Publication number: WO2012068894A1
Application number: PCT/CN2011/077491
Authority: WO
Inventors: 陈必多; 李明生; 卢金树
Original assignee: 中兴通讯股份有限公司
Priority date: 2010-11-25
Filing date: 2011-07-22
Publication date: 2012-05-31
Also published as: CN102480323B; CN102480323A

Abstract

The present invention provides a system and a method for implementing remote disaster recovery of an OLT. The system includes: an optical network unit ONU, a primary optical line terminal OLT, and at least one backup optical line terminal OLT. The ONU communicates with the primary optical line terminal OLT and the at least one backup optical line terminal OLT through an optical splitter node. The primary OLT comprises: a synchronization module, used for sending current configuration information and relevant parameters of the ONU to the corresponding ONU, and further used for omitting the configuration information and the relevant parameters of the ONU. The backup OLT comprises: a synchronization module, used for extracting configuration information and relevant parameters of the current ONU, and synchronizing configuration information and relevant parameters of the current ONU with the configuration information and the relevant parameters of the ONU of the primary OLT. The ONU comprises: a synchronization module, used for receiving configuration information and relevant parameters of the ONU, and forwarding the configuration information and the relevant parameters of the ONU to the primary OLT and the backup OLT. In the present invention, the primary OLT and the backup OLT implement message exchange through the ONU, thereby avoiding establishment of an additional message channel between the primary OLT and the backup OLT, and saving interconnection optical fiber between the primary OLT and the backup OLT.

Description

System and method for realizing remote disaster tolerance of optical line terminal

The present invention relates to a passive optical network (PON) technology, and more particularly to a system and method for implementing remote disaster recovery of an optical line terminal (OLT) in a passive optical network. Background technique

With the rapid growth of the access bandwidth requirements of the access network and the development of optical communication technologies and the reduction of cost, optical fiber communication is transparent to its services, has a long life span, and has almost unlimited bandwidth carrying capacity, and can adapt to the ever-increasing bandwidth and new business development needs. The characteristics of the access layer network construction, "light into the copper back", optical nodes gradually move down, fiber to the premises (FTTP, Fiber To The Premise), fiber to the building (FTTB, Fiber To The Building), Fiber to the Office (FTTO, Fiber To The Office) and Fiber To The Home (FTTH) have become an inevitable trend in the development of access layer networks.

As more and more services are carried by FTTx (FTTP, FTTB, FTTO, FTTH), the security requirements for FTTx are also increasing, including mobile backhaul (Backhaul) bearer, video real-time monitoring, power distribution. Network automation control, etc., all require the reliability of the FTTx network. As the OLT evolves toward large-capacity and small-office, and the convergence of access devices and aggregation devices, the role of the OLT in the network becomes more and more important, and the requirements for remote disaster recovery of the OLT are becoming more and more urgent.

The protection technology of the existing FTTx network is mainly for fiber protection. For example, in the patent applications of the application numbers 200610138880.4, 200710090069.8, and 200810106452.2, the protection for the optical fiber in the passive optical network is mainly given, and the cross-PON port is implemented on the OLT. Protection across PON boards, but not for protection across OLTs. The patent application with the application number 200710166383.X also provides a backup method for the OLT device, by configuring the backup group and passing between the OLTs. The advertisement packet and the backup packet are used to protect and back up the trunk path. Because the packets exchange between the OLTs are required, the packet channel between the active and standby OLTs increases the cost and increases the fault point. In addition, the active/standby switchover of this patent only considers the trunk fiber abnormality and cannot be linked with the uplink port.

In addition, the patent application with the application number of 201010142584.8 also mentions that the state of the uplink pseudowire is detected and associated with the downlink user equipment by means of Bidirectional Forwarding Detection (BFD) on the operator edge device (PE, Provider Edge). The connectivity between the CE and the customer equipment is implemented to improve the reliability of the service between the CE and the PE. However, the patent only provides a fault detection and service association, and does not implement cross-OLT protection. Summary of the invention

In view of the above, the main purpose of the present invention is to provide a system and method for implementing OLT remote disaster recovery, which implements message interaction through the ONU, and avoids establishing an additional message channel between the active and standby OLTs, thereby saving interconnection between the active and standby OLTs. optical fiber.

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

The present invention provides a system for implementing OLT remote disaster recovery, including an optical network unit ONU, a splitter node, a primary OLT, and at least one standby OLT, wherein the ONU communicates with the primary OLT and the standby OLT through the optical splitter node. The primary OLT includes: a synchronization module, configured to send current configuration information and related parameters of the ONU to the corresponding ONU; and is further configured to ignore the configuration information forwarded by the ONU and related parameters of the ONU; The OLT includes: a synchronization module, configured to extract the configuration information forwarded by the ONU and related parameters of the current ONU, and synchronize with the configuration information of the primary OLT and related parameters of the ONU; the ONU includes: a synchronization module, And receiving the configuration information and related parameters of the ONU, and forwarding the configuration information and related parameters of the ONU to the primary OLT and the standby OLT.

The synchronization module of the standby OLT is further configured to listen to the message sent by the ONU to the primary OLT. Or the protocol packet, including the ONU registration message or the dynamic host configuration protocol DHCP message, the Internet group management protocol IGMP message, the ONU registration information, the user IP address and the medium access control MAC, the binding information, and the multicast joining information of the ONU. At least one of them.

The primary OLT is configured to send the current configuration information and related parameters of the ONU to the corresponding ONU through the PON interface, where the configuration information includes the time when the PON port of the primary OLT is turned on/off, the primary OLT, and the standby OLT. The active/standby relationship; the related parameters of the ONU include the ranging information of the ONU.

The primary OLT and the standby OLT synchronize the configuration information and related parameters of the ONU through the physical layer operation maintenance management PLOAM message channel of the ONU.

In addition, the standby OLT is also used to interrupt the service of the primary OLT and the uplink network, and the OLT port status of the standby OLT is switched to the primary and the configuration is restored.

The present invention also provides a method for implementing OLT remote disaster recovery, wherein the ONU communicates with the OLT and at least one standby OLT through the optical splitter node, where:

Step A: The primary OLT sends the current configuration information and related parameters of the ONU to the corresponding ONU;

Step B: The ONU receives the configuration information and related parameters of the ONU, and forwards the configuration information and related parameters of the ONU to the primary OLT and the standby OLT;

Step C: The primary OLT ignores the configuration information forwarded by the ONU and related parameters of the ONU; the standby OLT extracts the configuration information forwarded by the ONU and related parameters of the current ONU, and the primary OLT The configuration information is synchronized with the relevant parameters of the ONU.

The configuration information includes the time when the PON port of the primary OLT is turned on/off, and the active/standby relationship between the primary OLT and the standby OLT. The related parameters of the ONU include the ranging information of the ONU.

After the step C, the method further includes:

When the primary OLT and the uplink network are interrupted and the active/standby switchover is required, the standby OLT switches its PON port status to the primary and performs configuration restoration. The method further includes: after the standby OLT switches to the primary state, re-ranging the ONU, and calculating a difference of the backbone optical fibers according to the previously collected ranging information of the ONU, and simultaneously configuring the current configuration information and the ONU. Related parameters are sent to the corresponding ONU.

In addition, the method further includes: the standby OLT intercepting a message or a protocol message sent by the ONU to the primary OLT, including an ONU registration message or a dynamic host configuration protocol DHCP message, an Internet group management protocol IGMP message, and acquiring an ONU At least one of registration information, a user IP address under the ONU, and a medium access control MAC, binding information, and multicast joining information.

The invention has the beneficial effects that the system and the method for implementing the OLT remote disaster recovery according to the present invention enable the active and standby OLTs to implement message interaction through the ONU, thereby avoiding the establishment of additional message channels between the active and standby OLTs, thereby saving the relationship between the active and standby OLTs. The OLT adds the synchronization module to the OLT to increase the ONU packet snooping and accelerates the service recovery after the active/standby switchover. In addition, the detection module detects the connectivity of the uplink interface and is associated with the active/standby switchover of the PON interface. The remote disaster recovery for the uplink network has been added to provide users with more complete protection measures. DRAWINGS

FIG. 1 is a schematic diagram of networking for implementing OLT remote disaster recovery according to the present invention;

Figure 2 is a diagram showing the internal module relationship of the OLT for implementing OLT remote disaster recovery;

Figure 3 is a diagram showing the internal module relationship of the ONU that implements OLT remote disaster recovery;

Figure 4 is a schematic diagram of a specific networking for implementing OLT remote disaster recovery.

FIG. 5 is a diagram of a PON port working state switching diagram for implementing OLT remote disaster recovery;

FIG. 6 is a flow chart of the PON port state switching timer timeout processing in the active/standby mode; FIG. 7 is a flow chart of the uplink connection initiated service connection detection;

Figure 8 is a flow chart of processing the primary and secondary switching messages;

Figure 9 is a flow chart of processing LOS messages in the primary and backup contention mode. detailed description

The basic idea of the present invention is: The ONU communicates with the primary OLT and the at least one standby OLT through the optical splitter node, wherein the primary OLT sends the current configuration information and related parameters of the ONU to the corresponding ONU; Configuring configuration information and related parameters of the ONU, and forwarding the configuration information and related parameters of the ONU to the primary OLT and the standby OLT; the primary OLT ignores the configuration information forwarded by the ONU and related parameters of the ONU; The standby OLT extracts the configuration information forwarded by the ONU and related parameters of the current ONU, and is synchronized with the configuration information of the primary OLT and related parameters of the ONU.

Hereinafter, a system and method for realizing OLT remote disaster tolerance of the present invention will be described in detail with reference to Figs.

The system for implementing OLT remote disaster recovery includes an ONU (Optical Network Unit), a splitter node, and at least two optical line terminals OLT. The OLT is a Gigabit-capable Passive Optical Network (OLT) OLT. As shown in Figure 1, each OLT provides a PON port to the optical splitter. The ONU is connected to the splitter branch optical path. The two PON ports of the OLT are configured in the protection group. Under normal working conditions, one of them The working status of the PON is Master (main), and the working status of the other PON port is Standby. The master and slave PONs use the ONU as a bridge to synchronize configuration data. In addition, the PON port listens to the packets sent by the ONU. Maintaining the registration status of the ONU and listening to some service packets sent by the ONU, facilitating faster switching of services.

Specifically, as shown in FIG. 2, the OLT includes a PON port, a configuration module, a switching control module, an uplink port, a detection module, and a synchronization module. The PON port mainly completes data transmission; the configuration module creates a protection group, and adds the PON port. In the protection group, the protection group is associated with the service connectivity of the uplink port, and the current configuration information of the protection group is transmitted to the switching control module and the detection module; and the switching control module is configured to detect the optical path signal loss of the PON port ( LOS, Loss of Signal) alarm, and support interaction with the detection module to achieve active/standby fiber switching control; The data transmission between the OLT and the uplink network is completed; the detection module performs service connectivity detection on the uplink port bound to the protection group according to the configuration information transmitted by the configuration module, and may also be directed to a virtual local area network (VLAN) of the uplink port. , Virtual Local Area Network), in which connectivity detection can use a variety of methods, such as BFD, Connectivity Fault Management (CFM), Υ·1731, etc.

The synchronization module on the primary OLT is configured to send the configuration information configured by the configuration module to the ONU through the PON interface, or periodically send the current ONU related parameters to the ONU through the PON interface. The configuration information includes the time when the PON port of the primary OLT is turned on/off, and the active/standby relationship between the primary OLT and the standby OLT. The relevant parameters of the ONU mainly include the ranging information of the ONU. The synchronization module on the OLT is configured to receive configuration data information from the ONU, so that the active and standby OLTs can synchronize the data through the ONU physical layer operations (Administration and Maintenance) message channel. In addition, the synchronization module on the standby OLT can also listen to messages or protocol packets sent by the ONU to the primary OLT, such as ONU registration messages or Dynamic Host Configuration Protocol (DHCP), Internet Group Management Protocol (IGMP, Internet Group). The management protocol) obtains the ONU registration information, and obtains the IP and Internet Protocol (IP) address and the media access control (MAC, Media Access Control) binding information and multicast join information of the user under the ONU, so that the active/standby switchover is performed. After that, it can speed up business recovery and reduce business flow interruption time.

As shown in FIG. 3, the ONU includes an uplink PON port and an ONU synchronization module, where the ONU synchronization module is configured to receive a PLOAM message related to configuration data in a specific format sent by the primary OLT, and then forward the message to the active and standby OLTs. The primary OLT can directly ignore the PLOAM message, and the standby OLT can process the PLOAM messages, and extract the configuration data of the primary OLT to ensure that the configuration data of the primary OLT is maintained on the standby OLT. Interruption time.

As shown in Figure 4, a specific networking diagram of OLT remote disaster recovery is implemented. Beam splitter, can The node is a 2: N splitter. The two nodes of the splitter are connected to two OLTs. The splitter is connected to the ONU by a branch fiber. The ONU can communicate with two OLTs simultaneously through the 2:N splitter.

In addition, the working state of the PON port includes the unprotected mode, the active/standby mode, the main working mode, and the standby working mode. The state switching is as shown in FIG. 5. The PON port defaults to the unprotected mode. When the PON port is added to the protection group, the state changes to the active-standby mode. After the main and standby competitions are completed, the PON port will switch to the main working mode if the competition succeeds. If the competition fails, the switch will switch to the standby working mode. After the active/standby switchover, the PON port status will be in the main working mode and the standby working mode. When the PON port is removed from the protection group, the PON port switches to the unprotected mode regardless of whether it is in the active/standby mode, the primary mode or the standby mode.

The method for implementing OLT remote disaster recovery of the present invention includes the following steps:

Step 100: The primary OLT sends the current configuration information and related parameters of the ONU to the corresponding ONU.

Step 200: The ONU receives the configuration information and related parameters of the ONU, and forwards the configuration information and related parameters of the ONU to the primary OLT and the standby OLT;

Step 300: The primary OLT ignores the configuration information forwarded by the ONU and the related parameters of the ONU. The standby OLT extracts the configuration information forwarded by the ONU and the related parameters of the current ONU to synchronize with the configuration information of the primary OLT and related parameters of the ONU. .

The primary OLT sends the current configuration information and related parameters of the ONU to the corresponding ONU through the PON interface, where the configuration information includes the time when the PON port of the primary OLT is turned on/off, and the active/standby relationship between the primary OLT and the standby OLT. ; ONU related parameters, including the ONU's ranging information.

In addition, after step 300, the following steps are further included:

When the primary OLT and the uplink network are interrupted and the active/standby switchover is required, the standby OLT switches the state of its PON port to the primary state, and then performs configuration recovery. After the standby OLT is switched to the primary state, the ONU needs to be re-ranged, and calculated according to the previously collected ranging information of the ONU. The difference between the backbone fibers ensures that the ONU services are forwarded normally. The current configuration information and related parameters of the ONUs are sent to the corresponding ONUs.

In a specific implementation, the present invention may include the following steps:

Step 11: Configure the protection group on the active and standby OLTs, and add the PON interface to the protection group. The PON interface is switched from the non-protected mode to the active/standby mode. When the PON ports of the two OLT protection groups enter the active/standby mode, the timer is started. The active and standby PON ports are closed according to the configured time interval and a random number is added. The PON port is turned off in turn. The purpose of adding random numbers is to ensure When the first ONU goes online, only one PON port is open. The status switch timeout timer message processing is as shown in Figure 6, waiting for the ONU to go online.

Step 12: After the first ONU is online and successfully registered, the OLT stops timing to turn off the PON port timer, and switches the PON port status from the active/standby mode to the primary mode, and simultaneously sets the ONU ranging information and The current PON port status is encapsulated into a PLOAM message and sent to the ONU. The ONU synchronization module resends the PLOAM message to all PON ports. After the OLT receives the PLOAM message, if the current PON state is in the active mode, the message is directly ignored. If the current PON state is in the active/standby mode, the PON port timer is stopped and the PON port status is removed. The active and standby race states are switched to the standby mode, and the PON port is turned off, and only all messages and data sent from the ONU are received.

Step 13: The primary PON port is configured with the uplink port associated with the protection group. The detection module inputs the configuration information of the uplink interface according to the configuration module, and initiates connectivity detection of the uplink port to the uplink device. Or 802. lag, etc., once the uplink service is interrupted, it can be guaranteed to complete the active and standby PON port switching within 50ms; also can use slow detection, such as PING detection, once the uplink service is interrupted, the switching control module can also be notified to perform the main Switching, but it is difficult to ensure that it is completed within 50ms. It can also directly detect the uplink optical port LOS. If the LOS appears on the uplink port and cannot be recovered in a short period of time, it is considered that the uplink service is interrupted, and the switching control module needs to be notified immediately. Perform active/standby switchover. The process is shown in Figure 7. When implementing, you can use BFD to connect General testing.

Step 14: Before the active/standby switchover occurs, the working state of the standby PON is always in the standby mode. The PON is turned off, but the receiver is turned on, and all PLOAM messages, OMCI messages, and data sent by the ONU are received. The synchronization module processes the PLOAM message, creates the corresponding ONU in the PLOAM message, and switches its state to the active state, and maintains the ONU ranging information in the PLOAM. After the active/standby switchover is performed, the standby PON port is switched to the active working state. The ONU can be quickly re-based and the service can be restored according to the saved information.

In addition, the active and standby switching of the PON port is triggered on the primary OLT, which mainly includes the following situations:

a) The primary OLT configuration module manually performs the active/standby switchover by using the command;

b) the OLT switching control module detects the PON optical path LOS;

c) The primary OLT detection module detects that the uplink port service connectivity is abnormal.

For the above a, b, the primary OLT turns off the PON port optical module to illuminate, and simultaneously updates the PON status to standby. After the ONU detects the PON optical path LOS, it will turn off the PON port optical module to emit light.

In addition, according to the configuration, the synchronization module listens to the message or the protocol message sent by the ONU to the primary OLT, including the ONU registration message or the dynamic host configuration protocol DHCP message, the Internet group management protocol IGMP message, and obtains the ONU registration information and the ONU user. The IP address and media access control MAC, binding information, and multicast join information. For service packets, the standby PON port does not forward and discards the PON port. This facilitates fast recovery after the active/standby switchover.

Step 15: The PON port detects the PON LOS alarm in the main working mode, or receives the manual switching command message sent by the configuration module, or receives the switching message of the detecting module, and the switching control module performs the active/standby switching processing flow. First, the type of the switching message is determined. For the manual switching or the PON optical fiber interruption alarm, the detection module is first notified to stop the uplink detection, and the PON port is turned off, and the PON port state is switched to the standby working mode; If the message is closed, the PON port is turned off, and the state of the PON port is switched to the standby mode. Processing flow The process is shown in Figure 8. After the main PON port is switched and the PON port is closed, the standby PON port detects that the ONU is not illuminated. Then, the standby PON port turns on the PON port to illuminate, and switches the state of the PON port to the active-standby mode.

Step 16: After the standby PON interface is switched from the standby working state module to the active/standby mode, the LOS recovery alarm is received (because the standby PON port is turned on and the ONU detects the LOS recovery alarm), and the current PON port is When the state is turned on, the working state is switched to the main working state, and the synchronization module is notified to perform configuration data recovery. The processing flow is shown in Figure 9. The switch is newly switched to the PON port in the main working state, and the data is recovered by the synchronization module, and the ONU is re-ranged, and the difference of the backbone fibers is calculated. After the business is restored, go to step 13.

In summary, according to the system and method for implementing OLT remote disaster recovery, the active and standby OLTs implement message interaction through the ONU, thereby avoiding the establishment of additional message channels between the active and standby OLTs, and saving the interconnection fibers between the active and standby OLTs. By adding a synchronization module, the standby OLT increases the listening of the ONU packets, which speeds up the service recovery after the active/standby switchover. In addition, the detection module detects the connectivity of the uplink interface and is associated with the active/standby switchover of the PON interface. For the remote disaster recovery of the uplink network, provide users with more complete protection measures.

The above is a detailed description of the present invention to enable those skilled in the art to understand the present invention. It is contemplated that other changes and modifications may be made without departing from the scope of the invention as claimed. Variations and modifications are within the scope of the invention.

Claims

Claim

A system for implementing remote disaster recovery of an optical line terminal OLT, characterized in that the system comprises an optical network unit ONU, a splitter node, a primary OLT and at least one standby OLT, and the ONU passes through the optical splitter node and the primary OLT. Communicate with the standby OLT, where

The primary OLT includes: a synchronization module, configured to send the current configuration information and related parameters of the ONU to the corresponding ONU; and is further configured to ignore the configuration information forwarded by the ONU and related parameters of the ONU;

The standby OLT includes: a synchronization module, configured to extract the configuration information forwarded by the ONU and related parameters of the current ONU, and synchronize with the configuration information of the primary OLT and related parameters of the ONU;

The ONU includes: a synchronization module, configured to receive the configuration information and related parameters of the ONU, and forward the configuration information and related parameters of the ONU to the primary OLT and the standby OLT.

The system for implementing OLT remote disaster recovery according to claim 1, wherein the synchronization module of the standby OLT is further configured to listen to a message or protocol message sent by the ONU to the primary OLT, including an ONU registration message. Or the dynamic host configuration protocol, the DHCP protocol, the Internet Group Management Protocol (IGMP) packet, and the at least one of the ONU registration information, the user IP address of the ONU, the medium access control MAC, the binding information, and the multicast joining information.

The system for implementing OLT remote disaster recovery according to claim 1, wherein the primary OLT is configured to send current configuration information and related parameters of the ONU to the corresponding ONU through the PON interface, where the The configuration information includes the time when the PON port of the primary OLT is turned on/off, and the active/standby relationship between the primary OLT and the standby OLT. The related parameters of the ONU include the ranging information of the ONU.

The system for implementing OLT remote disaster recovery according to claim 1, wherein the primary OLT and the standby OLT implement the configuration information and related parameters of the ONU through the physical layer operation maintenance management PLOAM message channel of the ONU. Synchronize.

5. The system for implementing remote disaster tolerance of an OLT according to claim 1, wherein: The OLT is also used to interrupt the service of the primary OLT and the uplink network. When the active/standby switchover is required, the OLT interface status of the standby OLT is switched to the primary and the configuration is restored.

A method for implementing the OLT remote disaster recovery, wherein the ONU communicates with the primary OLT and the at least one standby OLT through the optical splitter node, where the method includes:

The method for implementing OLT remote disaster recovery according to claim 6, wherein the configuration information includes a time when the PON port of the primary OLT is turned on/off, and a primary/secondary relationship between the primary OLT and the standby OLT; The relevant parameters include the ranging information of the ONU.

The method for implementing OLT remote disaster recovery according to claim 7, wherein after the step C, the method further includes:

When the primary OLT and the uplink network are interrupted and the active/standby switchover is required, the standby OLT switches its PON port status to the primary and performs configuration restoration.

The method for implementing OLT remote disaster recovery according to claim 8, wherein the method further comprises:

After the standby OLT is switched to the primary state, the ONU is re-ranged, and the difference between the backbone fibers is calculated according to the previously collected ranging information of the ONU, and the current configuration information and related parameters of the ONU are sent to the corresponding ONUs. .

The method for implementing OLT remote disaster recovery according to any one of claims 6 to 9, wherein the method further comprises: the standby OLT listening to a message or protocol sent by the ONU to the primary OLT. The packet includes the ONU registration message or the dynamic host configuration protocol DHCP message, the Internet group management protocol IGMP message, the ONU registration information, the user IP address of the ONU, the medium access control MAC, the binding information, and the multicast joining information. One.