KR100911271B1 - Oam data transmission apparatus and system - Google Patents

Abstract

The present invention relates to an OAM data transmission apparatus, a system and a method in an Ethernet network, and more particularly, an operation management channel using an existing Ethernet protocol in the data layer of an Ethernet device connected to a star Ethernet network. Minimizes the loss of resources through transmission channel due to operation management channel, and automatically allocates and removes operation management channel when expanding and removing RT without affecting service data, and enables operation management for RT. An apparatus, system, and method are provided.

Ethernet, optical transmission, subscriber network, remote management, OAM, PON, FTTH

Description

OAM DATA TRANSFER DEVICE AND SYSTEM {OAM DATA TRANSMISSION APPARATUS AND SYSTEM}

The present invention relates to an operation, administration and management (OAM) data transmission apparatus, a system and a method in an Ethernet network, and more particularly, in the data layer of an Ethernet device connected to a star Ethernet network. It provides the operation management channel by using the Ethernet protocol as it is, and minimizes the loss of resources due to the transmission channel due to the operation management channel and automatically allocates and removes the operation management channel when expanding and removing RT without affecting the service data. The present invention relates to an apparatus, a system, and a method for enabling an operation management for RT.

The rapid growth of the Internet has accelerated the complexities of voice, data, and video services, and various trends, and various multimedia services provided in real time with high-quality image quality such as distance education, high-quality VoD (Video on Demand), home shopping, and Triple Play Services (TPS). Are required. As a result of the emergence of new telecommunications business such as contents delivery network (CDN) and multimedia web hosting from simple internet access, the IP-xDSL, wireless access device, and home gateway are based on Internet Protocol (IP). Spread of Ethernet equipment such as Active Optical Network (AON) devices connecting Ethernet switches, Passive Optical Network (PON) devices connecting passive branch power splitters or Wavelength Mux / Demux devices It is becoming.

Ethernet equipment is a technology mainly used in Local Area Network (LAN), and there is a weak point in the operation management (OAM) of the equipment. Therefore, the administrator must register and manage the COT (Central Office Terminal) directly when registering and removing RT. In addition, the Ethernet layer does not provide a special channel for operation and management, which causes a problem that the operator has to go to the field in case of equipment failure or expansion. In particular, with the increase in the operation of Ethernet equipment in subscriber networks, the installation location of equipment is increasing in various outdoor environments such as electric poles / walls and roadsides as well as existing indoors. If the outdoor or indoor equipment is installed in a space that is not always managed by the operator, the operator should arrive at the site directly in order to take action in case of failure of the equipment, resulting in a delay in recovery time and an increase in operating costs.

In recent years, Ethernet-PON (E-PON), a PON-type Ethernet device that has been introduced to the market, proposes a method of setting and managing a separate protocol in the Media Access Control (MAC) area.

The present invention has been proposed to solve the above-mentioned problems of the prior art, and it is possible to immediately monitor the network situation when adding and removing RTs in a system connecting a plurality of Ethernet devices to a forming network while using the existing Ethernet protocol in the data layer. An object of the present invention is to provide an apparatus, a system, and a method for transmitting and receiving OAM data, by providing and removing an independent channel for the operation management function.

In the subscriber network, Optical Network Unit (ONU) for connecting to subscriber indoor devices such as COT, IP-xDSL equipment, Layer 2 Fast Ethernet Switch (FES) located in the office, and Optical Network Terminal (ONT) directly placed in subscriber's home Various RTs such as) are connected to the molding structure, which causes frequent ONU / ONT installation and removal at RT's request. Therefore, the COT should be able to immediately identify which channel the equipment is being removed and registered in, and immediately reflect the equipment registration and network status. The present invention provides a function of automatically assigning or deleting an OAM channel to the RT when expanding and removing the RT from the COT, and determining and controlling which channel of the COT itself is connected to the RT.

In addition, the present invention does not affect service data at all through an independent OAM channel provided to subscribers while minimizing loss of transmission channel resources due to allocation of an OAM channel between COT and RT, and vice versa. An object of the present invention is to provide an OAM data transmission apparatus, a system, and a method thereof, which can protect an operating system of a system by a software attack.

According to a first aspect of the present invention, an OAM data transmission device installed in a COT for operation and management (OAM) of an Ethernet network to which a central office terminal (COT) and at least one remote terminal (RT) are connected, and at least one RT A control unit for transmitting OAM data for operation management of the network management unit, receiving a response message from the RT for the OAM data through the network management unit, and performing registration, termination and remote management of one or more RTs; A network management unit for receiving OAM data from the control unit and transmitting the OAM data to the switch unit, receiving the OAM data from the switch and transmitting the OAM data to the control unit, and managing an internal network through OAM channel assignment and switching for one or more RTs; A switch unit for multiplexing service data and OAM data to a physical layer and demultiplexing service data and OAM data from the physical layer to the network manager; And a physical layer that transmits and receives service data and OAM data between the switch unit and the physical layer of the RT.

According to a second aspect of the present invention, an OAM data transmission apparatus installed in an RT for operation and management (OAM) of an Ethernet network to which a central office terminal (COT) and at least one remote terminal (RT) are connected, A controller for receiving and processing OAM data through a network manager, and for transmitting a response message for the OAM data to the network manager; A switch unit for multiplexing service data and OAM data to a physical layer and demultiplexing service data and OAM data from the physical layer to the controller; And a physical layer that transmits and receives service data and OAM data between the switch unit and the physical layer of the COT.

According to a third aspect of the present invention, an OAM data transmission system for operation and management (OAM) of an Ethernet network to which a central office terminal (COT) and at least one remote terminal (RT) are connected, and the OAM data transmission of the first aspect. COT with apparatus; And it provides an OAM data transmission system comprising a RT having an OAM data transmission apparatus of the second aspect.

According to the present invention, an independent channel for active operation management function by actively recognizing the network situation upon the expansion and removal of RT in a system that connects a plurality of Ethernet devices to a forming network while using the existing Ethernet protocol in the data layer. The present invention provides a device, a system, and a method for transmitting and removing OAM data.

In addition, according to the present invention, while minimizing the loss of transmission line resources due to the allocation of the management channel between the COT and RT, and does not affect the data serviced through the independent OAM channel provided to the subscriber at all, and vice versa It is possible to provide an OAM data transmission apparatus, a system, and a method thereof, which can protect an operating system of a system from harmful software attacks to be included in the system.

1 is a hierarchical structure of an OAM data transmission apparatus and system according to an embodiment of the present invention.

The physical layer is a Physical Coding Sublayer (PCS) layer (14, 19, 23, 28), Non-Return-to-Zero, Invert on Ones (NRZI) that codes / decodes, serializes, and parallelizes signals of the data layer to the physical layer. (Physical Medium Attachment) layer (15, 18, 24, 27) to convert / inverse transform into a signal form, and a Physical Medium Dependent (PMD) layer (16, 17, 25, 26) consisting of a transceiver.

The control unit 11 of the COT 10 manages registration and termination of the plurality of RTs 20 and exchanges OAM data with the network management unit 12. The network management unit 12 performs an internal network management role of exchanging OAM data between the control unit 11 and the switch unit 13 while allocating and switching control channels for operation management to the plurality of RTs 20.

The control unit 21 of the RT 20 interprets the path assignment message of the COT 10 to check the OAM channel of the RT 20, and the event history information of the device without affecting the service data through the assigned OAM channel. And transmits management information (OAM data) to the COT 10, receives the command from the COT 10, and executes the command.

2 is a block diagram of an OAM data transmission apparatus and system in a system having multiple Ethernet devices connected to a forming network in accordance with one embodiment of the present invention.

The system consists of an OLT 110 that operates as a COT (national company device) and one or more ONTs 120, 130, 140 that operate in RT and located in or around the user's home in the form of a forming network. The OLT 110 and the ONTs 120, 130, and 140 have a hierarchical structure as shown in FIG. 1.

Looking at the detailed configuration for each device, the OLT 110 and the control unit 111; A network manager 112; Switches 113, 114 and 115 for each channel; Each channel is composed of physical layers 116, 117, and 118. The control unit 111 of the OLT monitors the registration and release of the ONT (120, 130, 140) using the OAM channel setting message, and analyzes the RT management data while maintaining the network configuration status as the latest information. Process. In addition, the network manager 112 of the OLT 110 distributes the OAM channel to the ONT 120, 130, and 140 by using the OAM channel setting message of the controller 111. The switches 113, 114, and 115 for each channel perform muxing and demultiplexing of the service data and the OAM data. The physical layers 116, 117, and 118 of each channel of the OLT 110 are logically connected to the corresponding ONTs 120, 130, and 140.

The ONTs 120, 130, and 140 include the control unit 121, 131, and 141; Switches 122, 132, and 142; It is composed of physical layers 123, 133, and 143. The controllers 121, 131, and 141 interpret the information of the OAM channel setting message to grasp the channel location information of the RT, and the switches 122, 132, and 142 multiplex and demultiplex the service data and the OAM data. Demuxing is performed, and the physical layers 123, 133, and 143 are logically connected to the physical layers 116, 117, and 118 of the corresponding OLT channel.

COT's network management department manages the network to minimize the resource loss and impact of the subscriber service channel by the operation management channel. The first VLAN is used to manage two groups of virtual LANs (VLANs). The group is a group for service data transmission between the upper network and the lower network of the system, and the second group is a group for providing an OAM channel to the system. The first VLAN group is set in an untagged form to be independent of the frame format, so that all frames transmitted through the subscriber service channel can be transmitted at all times. The second VLAN group in port of switch 113, 114 and 115 of the OLT (110) between P0 and P _M and the tag (tagged) communicate to possess a specific VLAN ID value, ONT (120, 130, 140 ) The same applies to the ports of switches 122, 132, and 142.

In order to protect the operating system of the system from harmful software attacks that can be provided to the service data channel without affecting the OAM channel when the OAM channel is set up or completed, An embodiment of configuring a VLAN in a system will be described with reference to FIG. 2.

The control unit 111 of the OLT 110 periodically carries out different channel tags with different VLAN tags so as to deliver the location information to the final destination ONT 120 or 130 140 periodically or when necessary. OAM channel setting message is generated. Through the OAM channel setting message generated in this way, the ONT 120, 130, 140 can know its own location information. For example, in the OAM channel setting message, a message including Tag 0x101 is transmitted to ONT 1, a message including Tag Ox102 is transmitted to ONT 2, and a message including Tag 0x103 is transmitted to ONT 3, so that each ONT has its own location. Make sure you know the information.

In the case of the network management unit 112, the port P _M connected to the control unit 111 supports a function of tagging all VLANs, and transmits a frame to a position corresponding to the tag of the frame with respect to the frame from the control unit 111. . For example, if a tag 0x101 is entered, the tag is untaged to the port P1 to transmit the frame to the ONT1 (120), and if the tag 0x102 is attached to the port P2, the untaged frame is transmitted to the ONT2 (130).

Each channel switch 113, 114, 115 of the OLT 110 serves to separate service data and OAM data. OAM data from port P _M is tagged (0x2) to port P0. Similarly, OAM data coming into port P0 comes in with tag (0x2), and frames coming in through tag (0x2) are sent to port P _M. Service data from port P _S is forwarded unaltered to port P0. Similarly, service data from port P0 is forwarded without any change to port P _S except tag (0x2).

The switches 122, 132, and 142 of the ONT 120, 130, and 140 serve to separate service data and OAM data. For example, in the case of the ONT1 120, the OAM data coming in from the port P0 is tagged (0x2) and the frame is transmitted to the control unit 121 through the port P _M , and the position information is determined by viewing the data of the transferred frame. Done. On the contrary, the frame entered into the port P _M from the control unit 121 is tagged (0x2) to the port P0. Service data from port P _S is forwarded unaltered to port P0. Similarly, service data entering port P0 is forwarded unaltered to all traffic except tag (0x2).

3 is a flowchart illustrating an automatic allocation method of an OAM channel for RT according to an embodiment of the present invention, and FIG. 4 is a diagram illustrating an operation management channel allocation table according to an embodiment of the present invention. Hereinafter, an automatic allocation method of an OAM channel according to an embodiment of the present invention will be described with reference to FIGS. 3 and 4.

First, the control unit of the COT generates an OAM channel setting message including a virtual media access control (MAC) address (S302), and transmits the generated OAM channel setting message to the RT through a corresponding OAM channel (S304). The RT connected to the corresponding OAM channel receives the OAM channel establishment message (S306). Here, if there is no RT connected to the OAM channel, the OAM channel setting message is discarded, and the COT retransmits the OAM channel setting message periodically or at the request of the network manager. The control unit of the RT checks its own virtual MAC address through the received OAM channel setting message (S308) and checks the OAM channel assigned to itself based on the operation management channel allocation table (FIG. 4) stored in the RT. (S310). As shown in FIG. 4, the operation management channel assignment table includes channel information, a virtual MAC address, and a virtual IP address. Thereafter, the control unit of the RT identifies the virtual IP corresponding to the corresponding OAM channel by using the operation management channel assignment table and allocates the virtual IP to the RT (S312). The RT includes a virtual IP address assigned thereto and sends a response message to the COT informing that the OAM channel setup is completed (S314). The control unit of the COT receives and interprets a response message from the RT to register and update the location and OAM channel information of the RT to the COT (S316). After the registration and update of the OAM channel is completed, TCP (Transmission Control Protocol) communication is performed between the COT and the RT (S318) to continuously monitor the state and the communication state of the OAM channel (S320).

FIG. 5 is a transparent transmission path for accommodating the form of all Ethernet frames input through a service channel in order to supply an Ethernet service to a service channel for a subscriber without being influenced by the OAM channel at the time of setting up or after setting up an OAM channel. How to secure it. That is, it is a method for transmitting data without processing a frame even if any type of Ethernet frame enters the device.

In the OAM data transmission apparatus and system according to an embodiment of the present invention, the Ethernet network is internally configured with two VLANs to have the same effect as physically separating the paths of the operation management channel and the service channel for subscribers. As described above.

First, the switch (113, 114, 115, 122, 132, 142 in Fig. 2) determines whether the incoming Ethernet frame is a frame having a VLAN ID (S502). If the incoming Ethernet frame has a VLAN ID value, it is determined whether the VLAN ID value of the frame and the VLAN ID value set in the ports in the switch are the same (S504). If the VLAN ID value of the input frame and the VLAN ID value set in the ports in the switch match, the frame is transmitted to ports owning the same VLAN ID value (S506). If the input frame does not have a VLAN ID value or if it does not find a port that has a VLAN ID value but owns the same VLAN ID value in the switch, it does not process the input frame and transmits it through the output port corresponding to the input port. (S508).

According to the data transmission method illustrated in FIG. 5, even when an Ethernet frame having an externally set VLAN ID instead of the VLAN ID set according to the present invention is transmitted as it is through the output port corresponding to the incoming input port, the OAM channel is A transparent transmission path can be secured by accepting any type of Ethernet frame input through the service channel without being affected.

6 is a block diagram illustrating an example of another system implementation in accordance with the present invention. In the case of FIG. 2, the service data exchanged with each ONT is individually connected to the upper network, whereas in FIG. 6, the service data exchanged with each ONT is collected and connected to the upper network. In the case of Figure 2 is an independent channel-by-channel structure, even if any one channel has an advantage that does not affect the service of the other channel. In the case of Figure 6 is an economical system implementation method by integrating the switch and N channel switch in charge of the network management unit into a single switch.

7, 8, and 9 illustrate a method of implementing a physical connection for a logical connection between the OLT and the physical layer of the ONT shown in FIGS. 2 and 6.

In FIG. 7, a plurality of RTs 320, 330, and 340 are connected 1: 1 to point-to-point to multiple physical layer ports of the COT 310. Connection methods include the use of RJ45 and UTP cables, the use of optical fiber transmitters and optical receivers and two strands of optical fiber, the method of using a transceiver and one strand of optical fiber coupled by a wavelength-division filter, or different ports by port. The method of mixing the said method, etc. are mentioned.

In FIG. 8, an optical fiber is connected to a port having an optical transceiver physical layer of a COT 410 by a time division type PON (TDM-PON), and a plurality of RTs 430, 440, 450 is connected. Physically, they can be point-to-multipoint, or they can be virtually point-to-point within a certain time frame by separating each port in time.

In FIG. 9, a plurality of optical transceiver physical layers 511, 512, and 513 in a COT 510 are bundled by a wavelength branch combiner (Mux / Demux, 514) in a COT 510. It is connected to the wavelength branch coupler 520 corresponding to the Remote Node (RN) installed in the. In the RN 520, several RTs 530, 540, and 550 are connected. In this method, COT and RT are connected point-to-multipoint physically, but each channel is completely separated by wavelength and logically forms a point-to-point structure.

One modified method of the WDM-PON method is a boradband light source (BLS, 515, 516) of two different wavelength bands in the COT 510 to cancel the wavelength dependence between channels, and a passive device group for forming the optical path thereof. 517 may be included in the COT 510.

Those skilled in the art will appreciate that the present invention can be embodied in other specific forms without changing the technical spirit or essential features of the present invention. Therefore, it should be understood that the embodiments described above are exemplary in all respects and not restrictive. The scope of the present invention is indicated by the scope of the following claims rather than the detailed description, and all changes or modifications derived from the meaning and scope of the claims and the equivalent concept are included in the scope of the present invention. Should be interpreted.

1 is a hierarchical structure of an Ethernet device according to an embodiment of the present invention.

2 is a block diagram illustrating a system implementation in accordance with one embodiment of the present invention.

3 is a flowchart illustrating an automatic allocation method of an OAM channel for a remote terminal (RT) according to an embodiment of the present invention.

4 is a diagram illustrating an operation management channel allocation table according to an embodiment of the present invention.

5 is a flowchart illustrating a method for transmitting service data without being affected by an OAM channel according to an embodiment of the present invention.

6 is a block diagram illustrating an example of a system implementation in accordance with another embodiment of the present invention.

7 is a view showing the configuration of a system in which a plurality of RT and COT is connected to the forming network according to an embodiment of the present invention.

8 is a diagram illustrating a configuration of a TDM-PON system according to an embodiment of the present invention.

9 is a diagram illustrating a configuration of a WDM-PON system according to an embodiment of the present invention.

Claims (29)

OAM data transmission device installed in the COT for operation and management (OAM) of the Ethernet network to which the central office terminal (COT) and one or more remote terminals (RT) are connected. A control unit which transmits OAM data for operation management of one or more RTs to a network management unit, receives a response message from the RT for the OAM data through the network management unit, and performs registration, termination and remote management of one or more RTs; A network manager which receives the OAM data from the control unit and transmits the OAM data to the switch unit, receives the OAM data from the switch unit and transmits the OAM data to the control unit, and manages the internal network through OAM channel assignment and switching for one or more RTs; A switch unit for multiplexing service data and OAM data to a physical layer and demultiplexing service data and OAM data from the physical layer to the network manager; And It includes a physical layer for transmitting and receiving service data and OAM data between the switch unit and the physical layer of the RT, The switch unit determines whether the frame has a VLAN ID for the incoming frame, and if the frame has a VLAN ID, and transmits the incoming frame to a port that matches the VLAN ID set in the ports in the switch, and the determination result VLAN ID OAM data transmission, characterized in that it does not have or does not match the VLAN ID of the incoming frame and the VLAN ID set in the ports in the switch without processing the incoming frame through the output port corresponding to the input port Device. OAM data transmission device installed in RT for operation and management (OAM) of Ethernet network connected to Central Office Terminal (COT) and one or more Remote Terminals (RT), A control unit for receiving and processing OAM data from the COT through a network management unit and delivering a response message to the network management unit; A switch unit for multiplexing service data and OAM data to a physical layer and demultiplexing service data and OAM data from the physical layer to the control unit; And A physical layer for transmitting and receiving service data and OAM data between the switch unit and the physical layer of the COT, The switch unit determines whether the frame has a VLAN ID for the incoming frame, and if the frame has a VLAN ID, and transmits the incoming frame to a port that matches the VLAN ID set in the ports in the switch, and the determination result VLAN ID OAM data transmission, characterized in that it does not have or does not match the VLAN ID of the incoming frame and the VLAN ID set in the ports in the switch without processing the incoming frame through the output port corresponding to the input port Device. The method of claim 1, OAM data transmission device, characterized in that configured to integrate the network management unit and the switch unit. The method of claim 1, The control unit generates an OAM channel setting message and transmits it to the network management unit, and receives and analyzes a response message from the RT through the network management unit to manage OAM channel setting for RT connected to an Ethernet network. OAM data transmission device. The method of claim 2, The control unit receives the OAM channel setting message from the COT through the switch unit, and confirms the assigned OAM channel based on the stored management channel assignment table and the OAM channel setting message, and transmits a response message to the switch unit. OAM data transmission device characterized in that. The method according to claim 1 or 2, The switch unit OAM data transmission apparatus, characterized in that for distinguishing by setting the OAM data and the service data to different VLAN groups. The method of claim 6, The VLAN group for the service data does not have a VLAN ID. The method of claim 6, The VLAN group for the OAM data has an OAM data transmission device, characterized in that having a VLAN ID. The method of claim 1, Between the control unit and the network management unit, in order to distinguish OAM data other than the OAM channel setting message and the OAM channel setting message, the OAM channel setting message is transmitted in a tag manner and OAM data other than the OAM channel setting message. The OAM data transmission device, characterized in that transmitted in a tagless manner. delete The method of claim 4, wherein And the network manager transmits the OAM channel establishment message to the switch via the OAM channel assigned to the corresponding RT based on the VLAN ID included in the OAM channel establishment message. The method of claim 4, wherein The control unit transmits the OAM channel setting message to the RT periodically or at the request of the Ethernet network manager, characterized in that the OAM data transmission apparatus. OAM data transmission system for the operation and management (OAM) of the Ethernet network connected to the central office terminal (COT) and one or more RT (Remote Terminal), A COT including an OAM data transmission apparatus including the control unit, the network management unit, the switch unit, and the physical layer according to claim 1; And An OAM data transmission system comprising an RT comprising an OAM data transmission apparatus including the control unit, the switch unit, and the physical layer according to claim 2. The method of claim 13, Wherein said at least one RT is connected point-to-point to a plurality of ports of said COT. The method of claim 13, The at least one RT is connected point-to-multipoint with the COT by a Remote Node (RN) having a power splitter. The method of claim 13, The COT further includes a first wavelength distribution combiner coupled to one or more physical layers, Said at least one RT is connected point-to-multipoint with said COT by means of a second wavelength splitter. The method of claim 16, To eliminate inter-channel wavelength dependency, the COT further includes a passive element group constituting one or more BLSs and an optical path between the one or more BLSs. The method of claim 16, The first wavelength distribution combiner and the second wavelength distribution combiner are a thin film filter, The second wavelength distribution combiner is connected to the optical transmitter and the optical receiver of the COT and the OAM data transmission system, characterized in that. The method of claim 16, The first wavelength distribution combiner and the second wavelength distribution combiner are an arrayed waveguide grating (AWG), The second wavelength distribution combiner is connected to the optical transmitter and the optical receiver of the COT and the OAM data transmission system, characterized in that. The method of claim 16, The first wavelength distribution combiner and the second wavelength distribution combiner are each composed of two AWGs (Arrayed Waveguide Grating), The second wavelength distribution combiner is connected to the optical transmitter and the optical receiver of the COT and the OAM data transmission system, characterized in that. The method of claim 14, The COT and at least one RT is OAM data transmission system, characterized in that connected by RJ45 port and UTP cable. The method of claim 14, OT data transmission system, characterized in that the COT and at least one RT is connected by a two-core optical fiber. The method of claim 14, The COT and one or more RTs are OAM data transmission system, characterized in that connected by one core optical fiber. The method of claim 13, The Ethernet network is an OAM data transmission system, characterized in that connected by any one or more of FTTH, IP-xDSL, wireless communication or home gateway. As an OAM data transmission method in an Ethernet network including a central office terminal (COT) and one or more remote terminals (RT), The COT generating an OAM channel establishment message and transmitting it to RT; Checking, by the RT, the OAM channel information and the virtual IP assigned to the user based on the OAM channel establishment message and the stored management channel assignment table, and transmitting a response message to the COT through the identified OAM channel; Registering and updating the RT information based on the response message from the RT in the COT; Determining whether the COT is a frame having a VLAN ID for the incoming frame; Transmitting the received frame to a port corresponding to a VLAN ID set at ports in a switch included in the COT if the frame has a VLAN ID; If the determination result does not have a VLAN ID or does not match the VLAN ID set in the ports in the switch included in the COT, transmitting the incoming frame through an output port corresponding to an input port without processing the incoming frame. OAM data transmission method comprising a. The method of claim 25, The OAM channel establishment message includes virtual MAC information. The operation management channel assignment table includes channel information, virtual MAC information and virtual IP information. The method of claim 26, The RT checks its own virtual MAC address based on the virtual MAC information included in the OAM channel establishment message, and allocates OAM channel information and virtual IP corresponding to the virtual MAC address to itself in a stored management channel assignment table. OAM data transmission method characterized in that it is confirmed by the OAM channel and the virtual IP. The method of claim 25, The response message from the RT includes the virtual IP address allocated to the RT OAM data transmission method. The method of claim 25, Determining whether the RT is a frame having a VLAN ID for an incoming frame; Transmitting the incoming frame to a port corresponding to a VLAN ID set in ports in a switch provided to the RT if the frame has a VLAN ID; If the determination result does not have a VLAN ID or does not match a VLAN ID set in ports in the switch provided in the RT, transmitting the received frame through an output port corresponding to an input port without processing the incoming frame. OAM data transmission method characterized in that.

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