KR102335995B1 - Optical communication path bypass system - Google Patents

Abstract

An optical communication path bypass system of the present invention includes an SDN controller and an SDN agent unit. The SDN controller includes: a monitoring/determination unit which monitors whether there is a failure of an optical communication network including two or more COT devices that manage an optical communication ring, and determines whether switching to a detour path for the optical communication ring is necessary as a countermeasure for a detected failure; and a detour path switching unit which switches an optical path to the detour path. The SDN agent unit includes: a disability recognition unit which recognizes the occurrence of a failure on an OTRU side of the COT device; an OpenFlow agent which performs data communication with the SDN controller in a prescribed protocol; a COT control unit which carries out an instruction for the COT device of the SDN controller; and an IPC controller which performs data communication with each OTRU.

Description

Optical communication path bypass system {OPTICAL COMMUNICATION PATH BYPASS SYSTEM}

The present invention relates to an optical communication path bypass system and method in an optical communication network having a ring structure, and to an optical communication path bypass system and method to which SDN-based distribution automation technology is applied.

For the stable operation of the distribution system, the Distribution Automation System (DAS) is being operated to remotely monitor and control on-site distribution facilities.

DAS is first installed in downtown areas where buildings are dense, industrial areas that consume large amounts of electricity, schools, hospitals, etc., where important electricity customers are located, and the scope is expanding recently. In the DAS system, the COT is the central device of the optical communication network that plays the role of the backbone network, and generally accommodates the optical communication ring.

1 shows the normal operation of the optical communication ring of the distribution intelligent optical communication network and the operation in case of failure.

As shown on the left, the ring operation in the normal direction is performed in a normal state, and as shown on the right, in case of line failure (disconnection, etc.), bypass transfer (opposite direction, within 50 ms) is operated to maintain communication.

However, when the ORTU accommodating the optical ring in the COT fails, the entire optical communication ring accommodated in the OTRU is turned off, making it impossible to monitor and control the entire distribution system accommodated in the optical communication ring.

If it is impossible to monitor and control the DAS field facilities accommodated in the ring due to the OTRU failure of the COT, remote control of the distribution system due to emergency situations such as overload, vehicle dispatch, fire, etc. occurs widely.

However, in the case of an OTRU failure, the current COT has no way to recover from the failure other than replacing the OTRU. As such, when the communication equipment for automation introduced for the operation of the distribution system fails, there is a risk of making the entire distribution system uncontrollable.

In addition, it is possible to monitor the operation status of COT and RT by using the manufacturer's EMS (Equipment Maintenance System). Connection is required.

2 is a diagram showing the occurrence of failures in the distribution intelligent optical communication network operation structure for each branch in an independent operation method.

As shown in the figure, the current distribution automation system is installed for each branch and operated independently. Therefore, in the event of an OTRU failure of the COT of one branch, it is impossible to transfer to another branch and a failure occurs.

The distribution automation optical communication network shown had the ability to cope with failure at the level of simply switching in the East/West direction in case of an internal failure of one optical communication ring, but due to problems such as HOTRU in charge of the optical communication ring, There is no countermeasure for the entire failure of the ring and the failure of the COT. For this reason, in the event of an optical transmission equipment failure, the DAS communication network has no choice but to operate in a state where it is impossible to control and monitor all distribution system facilities accommodated in the optical communication network.

Republic of Korea Publication No. 10-2001-0075768

An object of the present invention is to provide an optical communication path bypass system and method that enables communication of an optical terminal (RT) even when a failure occurs in the optical communication network central unit side (COT/OTRU).

An optical communication path bypass system according to an aspect of the present invention monitors whether an optical communication network including two or more COT devices that manage an optical communication ring fails, and switches to a bypass path for the optical communication ring as a countermeasure for the detected failure a monitoring/judgment unit that determines whether a and an SDN controller having a detour path switching unit for switching an optical path to the detour path;

A disability branch recognizing the occurrence of a failure on the OTRU side of the COT device; an openflow agent performing data communication with the SDN controller in a prescribed protocol; COT control unit for performing an instruction to the COT device of the SDN controller; and an SDN agent unit including an IPC controller performing data communication with each OTRU.

Here, the disability recognition unit may periodically attempt communication with each of a plurality of OTRUs belonging to the COT device through the IPC controller, and may recognize the occurrence of an OTRU-side failure based on whether communication is possible for each OTRU.

Here, the detour path switching unit instructs the OTRU provided in the COT device to block or forward a managed optical communication ring, and block or forward OTRUs provided in other COT devices forming the detour path. can direct

Here, the COT control unit, an event handler for processing the event generated in the OTRU side or the event generated in the SDN controller; COT manager for processing the SDN control command transmitted to the COT device; and a COT state collector for collecting optical communication state information and Ethernet link network state information of the COT device.

A distribution automation system according to another aspect of the present invention performs a function of monitoring, controlling and measuring distribution facilities, and a central server having an SDN controller for remote control of the following COT devices, and optical terminals for distribution are connected a plurality of OTRUs connected to the optical communication ring; and a COT device having an SDN agent unit that controls the operation of each OTRU according to the instruction of the SDN controller.

Here, the SDN agent unit and the SDN controller may communicate using an OpenFlow protocol, and the SDN agent unit and the OTRUs may communicate by using IPC communication.

Here, each of the plurality of OTRUs has two optical cable connection terminals to which an optical communication cable can be connected, and some of the plurality of OTRUs are connected to an optical communication ring managed by a first terminal among the two optical cable connection terminals. and a second terminal is connected to a first terminal of an OTRU of another COT device, and the rest of the plurality of OTRUs, the two optical cable connection terminals may be connected to an OTRU of another COT device.

Here, the SDN agent unit and the plurality of OTRUs may be manufactured in the form of an expansion card having the same slot standard.

An optical communication path bypass method according to another aspect of the present invention, in an optical communication network including two or more COT devices for managing an optical communication ring, detecting the occurrence of a failure of the COT device; determining whether to switch to a detour path through another COT device; instructing a block for the optical communication ring of the COT device in which the failure has occurred, and instructing forwarding of the bypass path of the other COT device; and changing a service path for an optical terminal belonging to a switched optical communication ring according to the switching to the detour path.

Here, in the step of changing the service path for the optical terminal, the COT device in which the failure has occurred may perform MAC flushing control on the corresponding optical terminal.

Here, in the step of detecting the occurrence of a failure in the COT device, the OTRU of the COT device may periodically check the Alive status, and if there is no response to the Alive, it may be determined as the failure of the OTRU.

Here, the step of determining whether switching to the detour path is necessary may include: determining whether the detour path exists; determining the necessity of switching the detour path; and determining an operation for the COT sharing the detour path.

When the optical communication path bypass system and/or method according to the spirit of the present invention having the above configuration is implemented, there is an advantage of enabling uninterrupted power communication network operation even when a failure occurs in the optical communication network central unit side (COT/OTRU). .

The optical communication path bypass system and/or method of the present invention has the advantage of enabling uninterrupted network operation and stable power system operation by securing a detour route with optical communication equipment (COT) of a nearby business office even in case of HOTRU failure as well as optical ring failure. .

The optical communication path bypass system and/or method of the present invention has the advantage of contributing to the zero failure of the distribution automation communication network by performing intelligent, non-interrupted switching in the event of a communication network failure by utilizing the existing optical communication network infrastructure.

The optical communication path bypass system and/or method of the present invention has an advantage in that it is possible to respond to a real-time failure by automatically processing failure management in the system when a kidney failure occurs, thereby increasing facility operation efficiency.

The optical communication path bypass system and/or method of the present invention grafts the SDN technology to the existing optical communication network infrastructure, so that the technology implementation is easy and the practical effect of the technology application can be predicted. have.

1 is a conceptual diagram showing the normal operation and the operation in case of failure of an optical communication ring of a distribution intelligent optical communication network.
2 is a conceptual diagram showing the occurrence of failures in the distribution intelligent optical communication network operation structure for each branch in an independent operation method.
3 is a block diagram showing the overall configuration of a general distribution intelligent system (DAS).
4 is a block diagram illustrating the concept of an optical communication network central unit (COT).
5 is a conceptual diagram illustrating the SDN-based distribution automation optical communication network failure bypass structure.
6 is a block diagram illustrating an optical communication path bypass system according to an embodiment of the present invention.
Fig. 7 is a channel diagram illustrating a message channel for an SDN agent;
8 is a communication structure diagram illustrating a detailed structure of a communication channel between an SDN agent and an optical terminal connected to an OTRU;
9 is a data structure diagram showing the configuration of operational data of a communication channel between a DN agent and an optical terminal connected to an OTRU;
10 is a COT SDN agent sequence diagram for a network that forms an optical bypass path to a nearby branch as shown in FIG. 5;
Fig. 11 is an indication structure diagram showing an indication structure in the configuration of Fig. 7 when a light bypass path is formed;
12 is a block diagram illustrating detailed configurations of an SAU and an OTRU according to an embodiment of the present invention.
13 is a flowchart illustrating a disability recognition process through COT SAU.
14 is a flowchart illustrating an optical communication path bypass method according to an embodiment of the present invention.
15 is a conceptual diagram illustrating an OTRU connection configuration for switching in case of HOTRU failure of COT in the distribution automation system and a switching process in case of failure.

In describing the present invention, terms such as first, second, etc. may be used to describe various components, but the components may not be limited by the terms. The terms are only for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, a first component may be referred to as a second component, and similarly, a second component may also be referred to as a first component.

When a component is referred to as being connected or connected to another component, it may be directly connected or connected to the other component, but it can be understood that other components may exist in between. .

The terminology used herein is used only to describe specific embodiments, and is not intended to limit the present invention. The singular expression may include the plural expression unless the context clearly dictates otherwise.

In this specification, the terms include or include are intended to designate that a feature, number, step, operation, component, part, or combination thereof described in the specification exists, and includes one or more other features or numbers, It may be understood that the existence or addition of steps, operations, components, parts, or combinations thereof is not precluded in advance.

In addition, shapes and sizes of elements in the drawings may be exaggerated for clearer description.

First, an intelligent distribution system (DAS) to which the spirit of the present invention is implemented will be described.

3 shows the overall configuration of a general distribution intelligent system (DAS).

The configuration of the illustrated distribution intelligent system (DAS) is DAS main device 10 - Front End Processor (FEP) Server 20 - COT (Centrol Office Terminal) 40 - Optical cable - RT (Remote) Terminal) (50) - FRTU (Field Remote Terminal Unit) (70) - consists of a switch (80), and the communication method is Ethernet method for the DAS(10) ~ COT(40) section, and COT(40) ~ RT(50) ) section is composed of an optical Ethernet method, and the section RT(50) - FRTU(70) is composed of a serial (RS-232c) communication method.

The main device 10 of the illustrated distribution intelligent system (DAS) performs a function of monitoring, controlling, and measuring DAS facilities operated at the field by branch of a power company. The FEP server 20 receives the control command from the DAS main unit 10 and transmits it to the COT 40, which is the optical communication network main unit, in order to transmit it to the FRTU 70). The COT 40 converts the electrical signal received from the FEP server 20 into an optical signal and transmits it to the RT 50 connected to the FRTU 70 to be controlled through the optical cable installed on the electric pole.

The RT 50 converts the optical signal transmitted from the COT 40 through the optical cable into an electrical signal and transmits it to the FRTU 70 through the serial (RS-232c) method. The FRTU 70 interprets the serial signal RS-232c received from the RT 50 and transmits a control command to the switch 80 installed on the electric pole. The switch 80 executes a control command, and the switch status information according to the result is transmitted to the FRTU 70 - the DAS main device 10 in the reverse order.

Next, we will briefly discuss SDN.

SDN aims to prevent problems from occurring in the communication network and to minimize response time in case of problems.

SDN started with the idea of managing multiple devices simultaneously in one central location. The physical equipment of the network is divided into a control plane and a data plane. A module that processes user data is called a data plane, and a module that processes it is called a control plane.

Therefore, by running the control plane outside the machine, multiple management can be managed simultaneously from a central location. Through virtualization, it is possible to manage multiple devices with one controller.

The initial protocol of such SDN is OpenFlow. A protocol is a standard created for communication. It is a structure in which commands are exchanged according to a set standard called OpenFlow.

4 is a block diagram illustrating the concept of an optical communication network central device (COT). With reference to Fig. 4, we will look at the operation of the optical communication network (COT/RT) for the distribution automation system (DAS).

The optical communication network for DAS serves as a backbone communication network for communication between the main device and the optical terminal, and is composed of COT acting as the main device and RT acting as the optical terminal.

The COT monitors an Optical Trasmit and Reviever Unit (OTRU) 480 which is a communication unit through a Main Control Unit (MCU) 420 which is a control unit.

ORTU (eg, HOTRU) 480 configures an independent optical communication ring (Ring), one ring accommodates up to 30 RTs, and one COT accommodates up to 6 ORTUs (6 rings). COT can manage up to 180 RTs.

The monitoring information generated by the illustrated MCU 420 provides ring and optical terminal information to the operator through the manufacturer's EMS (Element Management System).

For example, the COT assigns an IP to each ORTU ring individually, and the RT accommodated in the ring communicates by designating port numbers 1 to 30.

The ORTU 480 communicates in two directions, East/West, in order to secure the availability of DAS even in the event of optical fiber and optical modem failure. Continuous communication with non-obstructed section and RT is performed through direction change in case of optical fiber section or corresponding RT failure.

In the present invention, in order to solve the problem that the entire optical communication ring becomes impossible when the COT itself or the OTRU 480 fails, the communication network (COT) for DAS that is installed and operated independently for each branch is interconnected and operated between branches. By improving the structure so that OTRUs in each branch are simultaneously controlled (switched over) by using SDN technology from the center, the function is implemented to enable uninterrupted monitoring and control of distribution facilities even in the event of a failure in the OTRU of a branch. .

5 is a conceptual diagram illustrating an SDN-based distribution automation optical communication network failure bypass structure.

5 shows a ring that was accommodated in one HOTRU (High Availability Seamless Redundancy (HSR) function applied to an existing OTRU) unit of the COT 400 in a branch and configured independently to transmit and receive a ring in the COT 400-1 of a nearby branch. It is configured to cross the transmission and reception by connecting in parallel with the . For this, a separate optical communication line between branch offices is used.

In the drawings and the description of the present invention, the OTRU is concretely described as a HOTRU to which HSR is applied, which is a technology without packet loss even in case of network failure through system replacement operation and no waiting time for switching. However, the spirit of the present invention may be implemented for a general OTRU, which also falls within the scope of the present invention.

6 is a block diagram illustrating an optical communication path bypass SDN system according to an embodiment of the present invention.

The illustrated optical communication path bypass system includes a Software Defined Network (SDN) controller 150 that is a SW module (or HW module) executed in the distribution center server 100 and a HW module (or SW module) can be roughly divided into the SDN agent unit 450 in the COT.

The SDN controller 150 monitors whether there is a failure of the optical communication network including two or more COT devices that manage the optical communication ring, and determines whether switching to a detour path for the optical communication ring is necessary as a countermeasure for the detected failure. /judging unit 154; and a detour path switching unit 156 for switching the optical path to the detour path.

More specifically, the detour path switching unit 156 instructs, for each COT device, block/forwarding/reversing of a managed optical communication ring (more specifically, a HOTRU connected to the corresponding optical communication ring cable), and , instructs blocking/forwarding/reversing of a detour path to another COT device (more specifically, a HOTRU connected to the detour path optical cable), and instructs the communication direction for modems of terminals provided in the optical communication ring. have.

In the drawing, the COT device 400 may be composed of one SDN agent unit 450 and a plurality of HOTRUs 481 to N.

The HOTRU of the prior art connects both ends of the optical cable of the optical communication ring in charge, whereas each of the illustrated HOTRUs is connected to only one end of the optical cable of the optical communication ring in charge, and a detour path is used with the remaining connection terminals. A clear distinction exists in that the optical cable shared with the HOTRU unit of other COT devices forming is connected.

The SDN agent unit 450 in the COT instructs the operation of each of the plurality of HOTRU units 481 to N according to an instruction from the SDN controller 150 .

The illustrated SDN agent unit 450 includes a disability identification unit (not shown) that recognizes the occurrence of a failure on the HOTRU side of the COT device 400; an openflow agent 451 for performing data communication with the SDN controller using a prescribed protocol; COT control unit 455 for performing an instruction to the COT device of the SDN controller; and an IPC controller 454 that performs data communication with each of the HOTRUs.

The disability recognition unit periodically attempts to communicate through the IPC controller 454 to each of a plurality of HOTRUs 481 to 48N belonging to the COT device, It can perform the function of recognizing the occurrence. Since the function is relatively simple, the disability recognition unit may be implemented as a SW function block of the IPC controller 454 or the COT controller 455 .

7 is a channel diagram illustrating a message channel for an SDN agent.

8 shows a detailed structure of a communication channel between an SDN agent and an optical terminal connected to a HOTRU.

9 shows a configuration of operational data of a communication channel between a DN agent and an optical terminal connected to a HOTRU.

As shown, the SDN command (instruction) issued by the SDN controller 150 is transmitted through the command channel to the optical terminal via the HOTRU 480, and status information or event information from the optical terminal is transmitted to the HOTRU 480. Through the event channel, it may be transmitted to the SDN controller 150 .

10 is a COT SDN agent sequence diagram for a network that forms an optical bypass path to a nearby branch as shown in FIG. 5 .

FIG. 11 shows an indication structure in the configuration of FIG. 7 when a light bypass path is formed.

For example, each COT device is a HW module in the form of an expansion card that performs optical communication for the optical communication ring. In addition to the expansion slot where the existing HOTRUs are installed, the SAU card supporting the SDN function built in the distribution center (server) can be installed. can

In other words, since the SDN controller can monitor and control the network switch operated based on OpenFlow, the SDN controller 150 is installed in the central distribution center and the SDN agent unit 450, which can accommodate the SDN protocol in each COT. 450-1) was installed.

The SDN agent unit may be further divided into a pure SDN agent module including the COT control unit 455 and an SDN controller 454 as a communication device with the HOTRU.

The OpenFlow protocol transmitted from the SDN controller 150 is interpreted through each mounted SAU 450 and 450-1 to control each HOTRU 480 and 480-1.

Each SDN agent unit (450, 450-1) accommodated in each COT issues a control command to each HOTRU (480, 480-1), and the HOTRU (480, 480-1) It performs the function of transmitting status information. The OpenFlow protocol transmitted from the SDN controller 150 is interpreted through the SAUs 450 and 450-1 to control the HOTRUs 480 and 480-1, and the detailed configuration of the SAU will be described later.

A network is configured so that one ring accommodated in the COT#1 HOTRU 480 of the branch A shown is accommodated together in one port of the COT#2 HOTRU 480-1 of the branch B. When a failure occurs in the HOTRU 480 of the branch A COT#1, the status information of the HOTRU 480 is converted to the OpenFlow protocol through the COT#1 SAU 450 and transmitted to the SDN controller 150, and the SDN controller 150 A HOTRU switch command is issued to the SAU 450 of COT#1 at branch A and SAU 450-1 of COT#2 at branch B through the OpenFlow protocol to perform switchover to COT#2 COT at branch B.

Branches A and B COT#1, #2 SAUs (450, 450-1) interpret this to perform switching for each HOTRU (480, 480-1), and branch A COT#1 SAU (450) is a HOTRU Blocking (480), branch B COT#2 SAU (450-1) activates HOTRU (480-1), and the ring accommodated in branch A COT#1 HOTRU (480) is branch B COT#2 HOTRU (480-2) ) is transferred to

12 is a block diagram illustrating a detailed configuration of an SAU and a HOTRU according to an embodiment of the present invention.

As previously seen in FIG. 6 , the SAU of the present invention includes a disability identification unit that recognizes the occurrence of a HOTRU-side failure; an openflow agent 451 that performs data communication using an openflow protocol; COT control unit 455 for performing an instruction to the COT device of the SDN controller; and an IPC controller 454 that performs data communication with the HOTRU.

The COT control unit 455 of FIG. 6 includes, in FIG. 12, an event handler 456 for processing an event generated from the HOTRU side or an event generated from the SDN controller; COT manager 457 for processing the SDN control command transmitted to the COT device; and a COT state collector 458 for collecting optical communication state information and Ethernet link network state information of the COT device.

As the OpenFlow standard itself tends to add functions, the OpenFlow agent 451 may further include an OpenFlow extension processing unit 452 for processing the extended OpenFlow message as a function block additionally divided into the OpenFlow agent 451. .

The OpenFlow agent 451 communicates with the OpenFlow protocol in order to interwork with the SDN controller, and can configure a function to receive and process a control command for a network flow table from the SDN controller.

The OpenFlow Extension Message 452 may configure a function to process the OpenFlow Extension Message defined for SDN extension control such as setting and inquiry of COT devices and networks.

The event handler 456 may configure a function to collect and process generated events such as COT device and network setting, inquiry, or SDN controller message.

The COT manager 457 configures a function to process the SDN control command transmitted from the SDN controller to the COT device, port Enable/Disable, port RateLimit setting, and port MTU (MTU: Maximum Transmission Unit, hereinafter referred to as MTU) setting. , Ethernet port Blocking/Forwarding setting, FEP server setting/deletion, etc. can be handled.

The COT status collector 458 may configure a function to collect and process failure alarms such as optical communication status of COT equipment and Ethernet link network status in real time.

Next, data communication performed by the OpenFlow agent 451 and the IPC controller 454 will be described.

A message channel for command and event processing is operated between the SDN controller and the SAU as shown in FIG. 7 . The message channel consists of an event channel and a command channel. The event channel is used to unidirectionally transmit a failure or emergency message from the SAU to the SDN controller. The command channel is structured to respond to a command request and is used to execute commands for setting or inquiry or to collect periodic status.

The SAU acts as a gateway to interpret the message through the command channel requested by the SDN controller and apply it to the HOTRU. When HOTRU receives an event, it converts it into an OpenFlow message and delivers it to the SDN controller through the event channel.

The SAU is composed of communication/processing means for HOTRU as an SDN agent processing unit and a device processing unit, and operates a process for message interpretation and message generation for each communication channel. The SDN agent communicates with the SDN controller using the OpenFlow protocol, and the device processing unit communicates with the HOTRU to collect bypass switch and device status and deliver it to the SDN agent processing unit. As shown in FIG. 8, the SDN agent processing unit and the device processing unit operate independently of each other, and interface data transfers data between processing units by a defined function call in consideration of scalability.

Data operated in SAU is largely classified and managed into information for switching and information on Ethernet port. Switching information consists of optical path failure, link failure, HOTRU communication status and switching information status. Fiber path failure measures the fiber LOS status at HOTRU, and the link status measures the link status of HOTRU and RT Ethernet ports constituting the ring.

The OTRU communication status is measured by periodically sending an Alive message to the HOTRU through the device command channel from the device processing unit. The switch state information provides the current switch state in the HOTRU. As shown in FIG. 9 , the Ethernet port information is composed of port operation state, rate limit control, and MTU control, so that setting and inquiry are possible.

The OpenFlow protocol exchange function between devices is shown in Table 1 below.

13 is a flowchart illustrating a disability recognition process through COT SAU.

With reference to FIGS. 12 and 13, operations continuously performed in the SAU for the above-described optical communication path bypass switching will be described.

The SAU 450 communicates with the SDN controller 150 through an openflow interface (protocol), and the SAU 450 periodically collects HOTRU failure information and switchover information. The SAU 450 configures the HOTRU for automatic switching when a HOTRU failure occurs. The SAU 450 provides failure information to the SDN controller 150 by determining that it is a failure even when information is not collected from the HOTRU 480 .

For the operation of the SAU 450, the HOTRU 480 collects information requested by the SAU through IPC communication, and sets information for automatic switching. Here, IPC communication is an abbreviation of InterProcess Communication, and is a mechanism that enables communication between executing processes. It is a multi-tasking operating system or networked problem regarding the rules for communication between processes, and information is exchanged between processes running between distributed computers. In IPC communication, it is very important to communicate according to a certain rule regardless of the host type, operating system, etc. In general, two processes communicate by exchanging messages according to a predetermined format and order.

The SAU 450 periodically checks the Alive state to the HOTRU 480 . If there is no response to Alive from the IPC controller, the SAU 450 determines that the HOTRU 480 is in a faulty state. Then, the IPC controller transmits an IPC failure event, and the SDN controller 150 performs a switching operation according to the failure event.

14 is a flowchart illustrating a method of bypassing an optical communication path according to an embodiment of the present invention.

In the optical communication path bypass method shown, in an optical communication network including two or more COT devices for managing an optical communication ring, detecting the occurrence of a failure of the COT device (S20); determining whether switching to a detour path is necessary (S40); Instructs the block for the optical communication ring managed by the failed COT device, and directs the forwarding (or reversing) of the bypass path of each COT device to the failed COT device and other COT devices sharing the bypass path step (S60); and changing the service path for the optical terminal device (RT) belonging to the optical communication ring that is switched according to the change of the detour path ( S80 ).

For example, the step of determining whether switching to the detour path is necessary (S40) may include, in the SDN controller, determining whether a detour path exists; the process of determining the necessity of diverting the detour; and determining an operation for the COT sharing the detour path.

For example, in the process of determining whether the detour path exists, it can be checked whether there is another COT device nearby that shares the detour path with the failed COT device in the configuration diagram information of the entire optical communication network.

For example, in the process of determining the necessity of switching the detour path, it may be checked whether there is a problem in the data packet processing capacity even if another identified COT device activates the detour path. Alternatively, from the accumulated related information on the previously performed detour path switching for the failed COT device, for example, there is a record in which a similar failure is immediately restored, or a record in which the operation efficiency of the entire optical communication network is significantly reduced when the same detour path is changed. If there is, it may be determined not to perform bypass switching.

For example, in the step (S80) of changing the service path for the optical terminal device (RT), the COT may perform MAC flushing control on the RT.

The illustrated optical communication path bypass method may perform an SDN controller function and an SAU interworking procedure for performing a bypass path switching function. That is, it is possible to reconfigure the COT ring through the SAU's disability (switching condition) and MAC communication.

SAU communicates with SDN controller through OpenFlow standard interface by embedding SDN Agent. SAU unit and HOTRU use MAC communication.

Specifically, after performing the function of transmitting disability recognition and failure information to the SDN controller through HORTU in SAU, the SDN controller through MAC communication controls HORTU through SAU and performs COT ring reconfiguration.

Here, the MAC communication serves to transmit the switching condition and switching operation as shown in Table 2 below.

The HOTRU provides the SAU with failure information (Blocking/Forwarding) necessary for bypass switching (S20). The fault information for bypass switching collects the HOTRU fault status from the SAU and provides it to the SDN controller (S20).

The SDN controller determines the collected HOTRU failure information and communication status (S40), and issues a command to perform bypass control control (S60).

The HOTRU performs Mac flushing control on the optical terminal device (RT) accommodated in the ring to change the service path when the bypass switching is performed (S60) (S80).

The distribution automation system proposed by the present invention, which applies the spirit of the present invention described above to the distribution automation system of FIG. 3, performs a function of monitoring, controlling, and measuring distribution facilities, and an SDN controller for remotely controlling the following COT devices A central server having a

a plurality of HOTRUs connected to an optical communication ring to which optical terminals for power distribution are connected; and a COT device having an SDN agent unit that controls the operation of each OTRU according to the instruction of the SDN controller.

Here, the SDN agent unit and the plurality of HOTRUs may be manufactured in the form of an expansion card having the same slot standard.

15 is a conceptual diagram illustrating a HOTRU connection configuration for switching in case of a HOTRU failure of the COT and a switching process in case of failure in the distribution automation system.

As shown. Each of the plurality of HOTRUs is provided with two optical cable connection terminals (E, W) to which an optical communication cable can be connected, some of the plurality of HOTRUs, a first terminal (E) of the two optical cable connection terminals connected to the optical communication ring managed by is connected with

The optical communication ring in charge of the illustrated first COT device (COT #1) is connected to the second terminal (W) of the second COT device (COT #2) providing a bypass path, and the illustrated first COT device (COT) An optical cable for a bypass path is connected to the second terminal W of #1), and the optical cable is connected to the first terminal E of the second COT device (COT #2).

HOTRU#1 unit failure is detected in the SAU unit of the first COT device (COT #1) shown, and when the SDN controller requests failure information, the COT#1 SAU unit responds to the failure status, thereby recognizing the failure state in the SDN controller. do. Then, the SDN controller determines that HOTRU#1 is Blocking and HOTRU#2 is forwarding, and the SDN controller sets HOTRU#1 and HOTRU#2 to switch at the same time. HOTRU#1 Forwarding→Blocking setting and HOTRU#2 Blocking→Forwarding setting are performed, and MAC flushing control can be performed from OT to RT.

Those skilled in the art to which the present invention pertains should understand that the present invention can be embodied in other specific forms without changing the technical spirit or essential characteristics thereof, so the embodiments described above are illustrative in all respects and not restrictive. only do The scope of the present invention is indicated by the following claims rather than the detailed description, and all changes or modifications derived from the meaning and scope of the claims and their equivalent concepts should be construed as being included in the scope of the present invention. .

100: distribution center server 150: SDN controller
154: monitoring/determination unit 156: detour path switching unit
400: COT device 450: SDN agent unit
451: openflow agent 452: openflow extension processing unit
454: IPC controller 455: COT control unit
456: event handler 457: COT manager
458: COT state collector
480, 481 ~ N : HOTRU

Claims (12)

a monitoring/determination unit that monitors whether there is a failure of an optical communication network including two or more COT devices that manage the optical communication ring, and determines whether switching to a detour path for the optical communication ring is necessary as a countermeasure for the detected failure; and
A detour path switching unit for switching the optical path to the detour path
An SDN controller comprising a;
A disability branch recognizing the occurrence of a failure on the OTRU side of the COT device;
an openflow agent performing data communication with the SDN controller in a prescribed protocol;
COT control unit for performing an instruction to the COT device of the SDN controller; and
IPC controller to perform data communication with each OTRU
Including an SDN agent unit comprising a,
The COT control unit,
an event handler for processing an event generated from the OTRU side or an event generated from the SDN controller;
COT manager for processing the SDN control command transmitted to the COT device; and
COT status collector for collecting optical communication status information and Ethernet link network status information of the COT device
Optical communication path bypass system comprising a.
According to claim 1,
The disabled branch,
An optical communication path bypass system that periodically attempts to communicate with each of a plurality of OTRUs belonging to the COT device through the IPC controller, and recognizes the occurrence of an OTRU-side failure based on whether communication is possible for each OTRU.
According to claim 1,
The bypass path switching unit,
An optical communication path bypass system for instructing the OTRU provided in the COT device to block or forward for a managed optical communication ring, and to instruct block or forwarding for OTRUs provided in other COT devices forming the bypass path.
delete delete delete delete delete delete delete delete delete

Images