JP4364580B2 - Optical transmission system and topology detection method - Google Patents

Description

  The present invention relates to an optical transmission system and an optical transmission device, and more particularly, to an optical transmission system and an optical transmission device using OXC (Optical Cross-Connect) technology that performs switching in a light state.

  The present invention also relates to a topology detection method, and more particularly to a topology detection method using an optical transmission system and an optical transmission apparatus using an OXC technology that performs switching in an optical state.

  Since an optical transmission apparatus is mainly used for a carrier or a backbone network, it is important to transmit a large amount of traffic at high speed without delay. However, the currently most popular SONET / SDH / OADX optical transmission equipment converts optical signals into electrical signals, switches them, converts them back into optical signals, and transmits them again. To do.

  On the other hand, since an OXC (Optical Cross-Connect) device performs switching (cross-connect) with light, there is no delay associated with conversion, and no hardware for electrical conversion and termination is required, thereby reducing the cost of the device. It has the merit that. For these reasons, the OXC device has attracted attention as a next-generation optical transmission device.

  In a network using an OXC apparatus, a technique for collecting a path information existing in the network by a network management system and constructing the network is known (for example, Patent Document 1).

  On the other hand, with the increase of data traffic due to the spread of the Internet and the like, the scale of the network has dramatically increased, and it is not a network management form in which provisioning is performed in units of one node as represented by TL-1 commands. A GMPLS (Generalized Multi-Protocol Label Switching) technique that enables provisioning at a time is attracting attention.

  This GMPLS technology is intended to enhance the maintenance protocol by extending the control protocol of the data IP network to be applied to the carrier network and integrating path setting and maintenance with the IP network. Up to now, MPLS (Multi-Protocol Label Switching) has realized signaling and routing only in the packet layer, but GMPLS is a technology for controlling routing and signaling over all layers of fiber / wavelength / TDM / IP. It is.

  In transmission and reception of control signals such as routing and signaling information, the conventional MPLS transmits the main signal and the control signal through the same channel. However, an OXC device to which GMPLS is applied uses an optical channel for transmitting the main signal as an optical signal. In order to perform cross-connecting as it is, it becomes impossible to superimpose and separate the main signal and the control signal by the same channel. Therefore, in the OXC apparatus, the data channel and the control channel are provided separately.

  In order to perform routing and signaling, each node needs to recognize the topology of which port of which OXC device (node) is connected to which port of an adjacent node.

  In the conventional MPLS, since the main signal and the control signal are transmitted on the same channel, each node recognizes the topology by exchanging the IP address of each device and port with the control signal.

    However, since the data channel and the control channel are separated in GMPLS, the conventional MPLS method cannot recognize the topology of the data channel. Although the administrator can set the topology information of the data channel to each node by a maintenance command, the number of data channels is enormous as thousands, so despite the fact that GMPLS was applied for the purpose of improving maintenance efficiency, Conversely, efficiency will be reduced.

  Therefore, at present, in the Internet Engineering Task Force (IETF), a Link Verification function for automatically detecting a topology using a link management protocol (LMP) is being studied.

  FIG. 1 is a sequence diagram illustrating a procedure of topology detection processing by the Link Verification function. First, an upstream OXC device (hereinafter simply referred to as “upstream node”) transmits a BeginVerify message to an adjacent downstream OXC device (hereinafter simply referred to as “downstream node”) through a control channel, and then the topology Request downstream node to start detection.

  When the downstream node is ready for topology detection, it returns a BeginVerifyAck message to the upstream node via the control channel and notifies the upstream node that the request has been accepted.

  Next, the upstream node selects one data channel, and transmits a Test message (topology detection message) to the downstream node a plurality of times at a predetermined time interval (VerifyInterval) VI using the selected data channel. Since the Test message is transmitted through the data channel, it is converted from an electrical signal to an optical signal and transmitted. In this Test message, an interface ID (port ID) assigned to the data channel in the upstream node is set.

  The downstream node first converts the optical signal into an electrical signal and extracts the Test message. When the Test message is received, the interface ID of the upstream node set in the Test message is extracted. Then, the downstream node creates a correspondence (mapping) between the extracted interface ID and the interface ID (port ID) assigned to the data channel that received the Test message.

  Next, the downstream node transmits a TestStatusSuccess message to the upstream node through the control channel. In this TestStatusSuccess message, the interface ID of the upstream node and the interface ID of the downstream node are set.

  By receiving the TestStatusSuccess message, the upstream node creates a mapping of the interface ID like the downstream node.

  By performing this kind of message exchange for all bidirectional data channels, it is possible to map the sending interface of the own node and the receiving interface of the partner node, and the receiving interface of the own node and the sending interface of the partner node. Thus, it is possible to realize accurate topology detection.

FIG. 2 is a sequence diagram illustrating the procedure of topology detection processing by link verification when a Test message is not received by a downstream node due to a data channel failure (for example, an optical fiber breakage). In this case, since the downstream node cannot receive the Test message, it transmits a TestStatusFailure message to the upstream node to notify the upstream node that it cannot receive it.
Japanese Patent Laid-Open No. 11-261512

  However, in such topology detection processing by the conventional Link Verification, the downstream node cannot know before which data the Test message is received by which data channel, so the optical signal is electrically transmitted for all the data channels. It required an O / E converter and a termination device for converting and terminating the signal.

  For this reason, the result is contrary to the merit that “the OXC is switched as it is, so that hardware for electrical conversion / termination is not required, and the cost of the apparatus can be reduced”.

  Accordingly, an object of the present invention is to provide an optical transmission system that can reduce hardware required for electrical conversion and termination processing and reduce apparatus cost.

  In order to achieve the above object, an optical transmission system according to a first aspect of the present invention transmits a data channel signal of an optical signal respectively transmitted through a plurality of data channels from an output port corresponding to each data channel. An optical transmission system comprising: an optical transmission device; and an adjacent second optical transmission device that receives a data channel signal transmitted by the first optical transmission device from an input port corresponding to each data channel. One optical transmission apparatus selects a generation unit that generates a topology detection message including identification information of the output port and outputs the topology detection message using an optical signal, and selects one of the plurality of data channels. A transmitter that transmits the topology detection message output from the generator; and a first control that controls selection of a data channel of the transmitter The second optical transmission device selects a termination unit that converts an input optical signal into an electrical signal and terminates the signal, and selects one of the plurality of data channels, and the signal of the selected data channel A selection unit that inputs to the termination unit, a second storage unit that stores a correspondence relationship between the identification information of the output port and the identification information of the input port, and the selection of the data channel of the selection unit, When the termination unit receives the topology detection message from the selection unit, the identification information included in the received topology detection message, and the identification information of the input port of the data channel selected by the selection unit, Is stored in the second storage unit, and when the termination unit does not receive the topology detection message, the data channel selected by the selection unit is changed to another data channel. And it includes a second controller to change channel.

  The topology detection method according to the first aspect of the present invention is executed between adjacent first optical transmission devices and second optical transmission devices that transmit and receive optical data channel signals respectively transmitted by a plurality of data channels, A topology detection method for detecting a connection relationship between an output port of the first optical transmission apparatus and an input port of the second optical transmission apparatus, wherein the first optical transmission apparatus is one of the plurality of data channels. The topology detection message including the identification information of the output port of the selected data channel is transmitted using the selected data channel, and the second optical transmission apparatus selects one of the plurality of data channels. When the topology detection message is received on the selected data channel, the output included in the received topology detection message And the identification information of the input port of the selected data channel are stored in association with each other, and when the topology detection message is not received in the selected data channel, another data channel is selected. And terminate.

  An optical transmission device according to a second aspect of the present invention receives optical data channel signals respectively transmitted through a plurality of data channels, and switches the received plurality of data channel signals in an optical state by an optical switch unit. An optical transmission device that transmits an input optical signal to an electrical signal and terminates the data, and selects one of the plurality of data channels, and selects a data channel signal of the selected data channel. The selection unit provided to the termination unit and the selection of the data channel of the selection unit are controlled, and when the termination unit does not receive a signal from the selection unit, the data channel selected by the selection unit is changed to other data. And a control unit for changing to a channel.

  An optical transmission apparatus according to a third aspect of the present invention receives optical data channel signals respectively transmitted through a plurality of data channels, and switches the received plurality of data channel signals in an optical state by an optical switch unit. An optical transmission device that transmits an optical signal and terminates by converting an input optical signal into an electrical signal, and selects one of the plurality of data channels by controlling switching of the switch unit, A control unit that applies a data channel signal of the selected data channel to the termination unit and changes a data channel selected by the optical switch unit to another data channel.

  An optical transmission apparatus according to a fourth aspect of the present invention receives optical data channel signals respectively transmitted through a plurality of data channels, and switches the received plurality of data channel signals in an optical state by an optical switch unit. An optical transmission device that transmits a topology detection message for detecting a data channel connection relationship with an optical transmission device adjacent to the downstream side, and outputs the topology detection message as an optical signal, and the plurality of data A transmission unit that selects one of the channels, and transmits the topology detection message output from the generation unit to the downstream optical transmission device using the selected data channel.

  An optical transmission apparatus according to a fifth aspect of the present invention receives optical data channel signals respectively transmitted by a plurality of data channels, and switches the received plurality of data channel signals in an optical state by an optical switch unit. An optical transmission device that transmits a topology detection message for detecting a data channel connection relationship with an optical transmission device adjacent to the downstream side, and outputs the topology detection message to the optical switch unit by an optical signal; The switching of the optical switch unit is controlled to select one of the plurality of data channels, and the topology detection message output from the generation unit is transmitted to the downstream side by the selected data channel. And a control unit that controls to transmit to the apparatus.

  An optical transmission system according to a sixth aspect of the present invention includes: a first optical transmission device that transmits optical data channel signals respectively transmitted through a plurality of data channels from output ports corresponding to the respective data channels; An adjacent second optical transmission device that receives a data channel signal transmitted by the optical transmission device from an input port corresponding to each data channel, and further between the first optical transmission device and the second optical transmission device The first optical transmission apparatus includes a generation unit that generates a topology detection message including identification information of the output port and outputs the topology detection message as an optical signal, and a plurality of data channels. One data channel is selected as a termination data channel, and the topology detection message output from the generation unit is transmitted by the selected data channel. A transmission control unit, a first control unit that controls selection of a data channel of the transmission unit, and a monitoring timer that detects a response signal from the second optical transmission device to the topology detection message on the control channel. The second optical transmission device selects a termination unit that converts an input optical signal into an electrical signal and terminates the signal, and selects one of the plurality of data channels, and transmits the signal of the selected data channel to the termination unit. A selection unit that inputs to the second storage unit that stores a correspondence relationship between the identification information of the output port and the identification information of the input port, and controls the selection of the data channel of the selection unit. When the topology detection message is received from the selection unit, the identification information included in the received topology detection message and the data chart selected by the selection unit And a second control unit for storing the identification information of the input port of the channel in the second storage unit in association with each other. When the first optical transmission device does not receive the response signal within one channel monitoring timer period by the monitoring timer, the first control unit selects a new data channel to be terminated, and In the two-optical transmission apparatus, the selection unit selects one of the new data channels when the topology detection message is received.

  According to the first aspect of the present invention, in the second optical transmission apparatus, one of the plurality of data channels is selected by the selection unit, and the selected data channel signal is converted into an electrical signal and terminated. Is input to the terminal portion. Therefore, only one termination is required, and there is no need to provide a termination for each data channel. Thereby, apparatus cost is reduced.

  According to the first aspect of the present invention, in the first optical transmission apparatus, one of a plurality of data channels is selected, and a topology detection message including output port identification information is generated by the selected data channel. A topology detection message output from the generation unit that outputs the optical signal is transmitted. Therefore, only one generating unit is required, and this also reduces the apparatus cost.

  According to the second and third aspects of the present invention, only one termination is required, and it is not necessary to provide a termination for each data channel. Thereby, apparatus cost is reduced. In particular, according to the third aspect, since the optical switch unit is also used for selecting the data channel, the apparatus cost is further reduced.

  According to the fourth and fifth aspects of the present invention, only one generator is sufficient, and it is not necessary to provide a generator for each data channel. Thereby, apparatus cost is reduced. In particular, according to the fifth aspect, since the optical switch unit is also used for selecting the data channel, the apparatus cost is further reduced.

  Also according to the sixth aspect of the present invention, the topology detection of a plurality of data channels can be performed at high speed by one electrical termination function. Thereby, apparatus cost is reduced. According to the sixth aspect, since the optical switch unit is also used for data channel selection, the device cost is further reduced.

  Embodiments of the present invention will be described below with reference to the drawings. The embodiments described below are for understanding the present invention, and the application of the present invention is not limited to these embodiments.

  FIG. 3 is a block diagram showing a part of the optical transmission system according to the first embodiment of the present invention. This optical transmission system has a plurality of OXC devices (hereinafter referred to as “OXC nodes”), and the plurality of OXC nodes are connected in various connection forms such as a ring shape and a mesh shape. FIG. 3 shows three OXC nodes A to C connected in a straight line (linear form) as a part thereof.

  Between the OXC nodes A and B, a transmission path L1 for transmitting user data (main signal) and a transmission path L2 for transmitting control data (control signal) are individually provided. User data is transmitted by an optical signal, and the transmission line L1 is configured by one or a plurality of optical fibers. The control data is transmitted by an electric signal or an optical signal, and the transmission path L2 is configured by a physical medium corresponding to the control data.

  The transmission line L1 is provided with one or a plurality of data channels, and user data is transmitted through the data channels. A control channel is provided in the transmission line L2, and control data is transmitted through the control channel.

  When a plurality of data channels are provided, one optical fiber may be assigned to one data channel, or one optical fiber is assigned to a plurality of data channels. In some cases, a plurality of data channels are transmitted by wavelength division multiplexing (WDM).

  Similarly, a transmission line L3 for transmitting user data and a transmission line L4 for transmitting control data are individually provided between the OXC nodes B and C, and a data channel is transmitted on the transmission line L3. A control channel is provided for each of the paths L4.

  Note that the data channel is unidirectional, and in the example of FIG. On the other hand, the control channel is bidirectional.

  In this optical transmission system, an optical path that is a path for transmitting an optical signal through a data channel is set. In FIG. 3, as an example, an optical path P is set on a route from OXC node A to B through B.

  The OXC nodes A to C all have the same configuration. FIG. 4 is a block diagram showing the configuration of the OXC node according to the first embodiment of the present invention. In the figure, solid arrows indicate the flow of control signals, and broken arrows indicate the flow of data signals (main signals). The same applies to other embodiments described later.

  The OXC node includes a command interface control unit (command IF control unit) 11, a control channel interface unit (control channel IF unit) 12, a link management protocol control unit (LMP control unit) 13, a control signal termination unit 14, and optical / electrical conversion. Unit (O / E conversion unit) 15, optical switch unit 16, optical reception interface unit (optical reception IF unit) 17, optical transmission interface unit (optical transmission IF unit) 18, and topology database (topology DB) 20.

  The command IF control unit 11 accepts a TL-1 command (maintenance command), an SNMP (Simple Network Management Protocol) command, or the like input from an administrator or a management system, checks the received command, and sets arguments included in the command. Perform extraction and so on. The accepted command and the extracted argument are given to the LMP control unit 13. Further, the command IF control unit 11 notifies the administrator or the management system of the command processing result.

  The control channel IF unit 12 executes interface processing for communicating control signals through the control channel, and terminates a data link (mainly IP) carrying a signaling protocol and a routing protocol executed via the control channel. .

  A control channel is provided for each adjacent OXC node. For example, OXC node B in FIG. 3 has a control channel for adjacent OXC node A and a control channel for adjacent OXC node C. The former control channel is used to manage and control the data channel between OXC nodes A and B. The latter control channel is used to manage and control the data channel between OXC nodes B and C.

  Each control channel is assigned a control channel ID for identifying the control channel. This control channel ID is a unique identifier within each node. For example, in the OXC node B of FIG. 3, # 1 is assigned as the control channel ID for the control channel for node A, and # 2 is assigned as the control channel ID for the control channel for node C, for example.

  When a plurality of control channels are provided, the control channel IF unit 12 performs the above processing for a plurality of control channels.

  The LMP control unit 13 executes a link management protocol (LMP) and terminates the LMP. The LMP mainly (1) confirms the management number for the link used between adjacent nodes, (2) identifies the location of the failure in the data channel, (3) maintains and monitors the control channel, (4) detects the topology of the data channel, It has the function of.

  In addition to these functions, the LMP control unit 13 controls an optical selector (described later) and an optical multiplexer (described later) of the optical reception IF unit 17 and a multiplexer (described later) of the optical transmission IF unit 18 to control the topology. Perform detection processing.

  The control signal termination unit 14 terminates the electrical signal (Test message) input from the O / E conversion unit 15. Specifically, the control signal termination unit 14 frames (frames) the electrical signal input from the O / E conversion unit 15 into a physical layer transmission format, and extracts a control packet from the frame. The extracted control packet is given to the LMP control unit 13. Also, the control signal termination unit 14 inserts the control packet given from the LMP control unit 13 into the frame in the reverse order, and gives the frame to the O / E conversion unit 15.

  Conventionally, the control signal termination unit 14 is provided for each data channel. As a result, the control signal termination unit 14 is provided in the same number as the number of data channels. However, in this embodiment, the number is less than the number of data channels. Only one is provided. Thereby, apparatus cost is reduced.

  The O / E conversion unit 15 converts the optical signal (Test message) given from the optical reception IF unit 17 into an electrical signal and gives it to the control signal termination unit 14, and also the electrical signal given from the control signal termination unit 14 Is converted into an optical signal and supplied to the optical transmission IF unit 18.

  Conventionally, the number of O / E converters 15 is also provided for each data channel, and the number of O / E converters 15 is the same as the number of data channels. Yes. Thereby, apparatus cost is reduced.

  The optical switch unit 16 switches the optical signal of the data channel input from the optical reception IF unit 17 in the state of the optical signal, and outputs it to the optical transmission IF unit 18.

  The optical reception IF unit 17 outputs an optical signal of a data channel input from an upstream node via an input port (not shown) to the O / E conversion unit 15 or the optical switch unit 16. When an optical signal is input to the OXC node by WDM, a demultiplexer is provided in the preceding stage of the optical reception IF unit 17, and the data channel signal demultiplexed for each wavelength by the demultiplexer is an optical reception IF. It will be input to the unit 17.

  In this embodiment, as shown in FIG. 5, as an example, it is assumed that optical signals of three channels of data channels Dch1 to Dch3 are input to the optical reception IF unit 17. Input ports (interfaces) (not shown) are provided corresponding to the respective data channels. Therefore, at least three input ports are provided in this embodiment. Each input port is assigned an interface ID (input interface ID) that is an identifier for identifying the input port. This interface ID is a unique identifier in the node. For example, interface IDs # 1 to # 3 are assigned to the input ports of the data channels Dch1 to Dch3, respectively.

  FIG. 5 is a block diagram showing a detailed configuration of the optical reception IF unit 17. The optical reception IF unit 17 includes optical selectors (SEL) 17a to 17c and an optical multiplexer (MUX) 17d.

  The optical signals of the data channels Dch1 to Dch3 are input to the SELs 17a to 17c, respectively. The SELs 17 a to 17 c output the input optical signal to the MUX 17 d or the optical switch unit 16 based on the control signal from the LMP control unit 13. Based on the control signal from the LMP control unit 13, the MUX 17 d selects one of the optical signals from the SELs 17 a to 17 c and outputs it to the O / E conversion unit 15.

  Returning to FIG. 4, the optical transmission IF unit 18 selects one of the optical signal from the optical switch unit 16 or the optical signal from the O / E conversion unit 15, and sends the selected optical signal via the output port (interface). To the downstream node. An interface ID (output interface ID), which is a unique identifier within the node, is also assigned to the output port. For example, interface IDs # 1 to # 3 are assigned to the output ports of the data channels Dch1 to Dch3, respectively.

  When a data channel signal is transmitted by WDM, a multiplexer is provided after the optical transmission IF unit 18, and each data channel signal is wavelength-multiplexed by this multiplexer and transmitted. .

  FIG. 6 is a block diagram showing a detailed configuration of the optical transmission IF unit 18. The optical transmission IF unit 18 includes optical multiplexers (MUX) 18a to 18c. The optical signals of the data channels Dch1 to Dch3 are input to the MUXs 18a to 18c, and the optical signal from the O / E converter 15 is input. Each of the MUXs 18a to 18c selects one of the two input optical signals based on the control signal from the LMP control unit 13, and outputs the selected input optical signal.

  Returning to FIG. 4, the topology DB 20 is configured by a storage device such as a semiconductor memory and a hard disk, and is used for managing the data channel management table and the control channel used by the LMP control unit 13 to manage the data channel. A control channel management table is stored.

  FIG. 7 shows an example of the data channel management table. The data channel management table includes data channel management data corresponding to each interface ID. Each data channel management data is indexed by the interface ID of the data channel and can be searched by the interface ID. For example, FIG. 5 shows a state in which each data channel management data of the interface IDs # 1 to # 3 is indicated (indexed) by the interface IDs # 1 to # 3.

  Each data channel management data has data items of control channel ID, topology detection presence / absence, and remote interface ID.

  The control channel ID is an identifier of a control channel that manages the data channel. In FIG. 5, control channel ID # 1 is shown as an example. The presence / absence of topology detection is a flag indicating whether the interface ID of an adjacent node (upstream node or downstream node) connected to the interface (port) has already been detected by the topology detection process. When this flag is 0, the topology is not detected, and when it is 1, it means that the topology has been detected.

  The remote interface ID is an identifier of an interface of an adjacent node connected to the interface, and includes a node ID of the adjacent node and an interface ID of the adjacent node. The node ID is an identifier for identifying a certain node from other nodes in the optical transmission system, and is a unique identifier in the network of the optical transmission system. For example, an IP address is used as the node ID.

  The remote interface ID is written by the LMP control unit 13 based on the Test message or TestStatusSuccess message transmitted / received by the topology detection process.

  FIG. 8 shows an example of the control channel management table. The control channel management table includes control channel management data corresponding to each control channel ID. Each control channel management data is indexed by the control channel ID of the control channel, and can be searched by the control channel ID. For example, FIG. 8 shows a state in which the control channel management data of the control channel ID # 1 is indicated (indexed) by the control channel ID # 1.

  Each control channel management data includes data items of the number of data channels managed by the control channel and the interface ID (group) of the data channel managed by the control channel. In FIG. 8, as an example, 3 are shown as the number of data channels, and three data channel interface IDs # 1 to # 3 are shown as interface IDs.

  Next, a message transmitted and received for topology detection from the OXC node having such a configuration will be described. This message includes a BeginVerify message, a BeginVerifyAck message, a Test message, a TestStatusSuccess message, a TestStatusAck message, etc. defined by LMP.

  FIG. 9 shows the data structure of the BeginVerify message. The BeginVerify message is a message for a node (upstream node) that starts topology detection to notify the adjacent counterpart node (downstream node) of the start of topology detection, and is transmitted via the control channel.

  This BeginVerify message has data items of “IP Header” (a), “Common Header etc” (b), and “BEGIN # VERIFY Class” (c). “IP Header” (a) is a header defined by the Internet Protocol (IP). “Common Header etc” (b) includes the node ID of the upstream node that transmitted this BeginVerify message. “BEGIN # VERIFY Class” (c) includes data such as “VerifyInterval” (ca) and “Number of Data Links” (cb).

  “VerifyInterval” (ca) is the transmission interval of the Test message, and is set by the LMP control unit 13 of the upstream node. In FIG. 9, 100 ms is set as an example. “Number of Data Links” (cb) is the number of data channels on which topology detection is performed, and is set by the LMP control unit 13 of the upstream node. In FIG. 7, 3 is set as an example.

  FIG. 10 shows the data structure of the BeginVerifyAck message. The BeginVerifyAck message is a message that the downstream node that has received the BeginVerify message returns to the upstream node as a confirmation response, and is transmitted via the control channel.

  This BeginVerifyAck message has data items of “IP Header” (a), “Common Header etc” (b), “BEGIN # VERIFY # ACK Class” (d), and “VERIFY # ID Class” (e).

  “Common Header etc” (b) includes the node ID of the downstream node that transmitted this BeginVerifyAck message. “BEGIN # VERIFY # ACK Class” (d) includes “VerifyDeadInterval” (da). “VerifyDeadInterval” (da) is the time from when the downstream node transmits the BeginVerifyAck message to when it transmits the TestStatusFailure message, and is set by the LMP control unit 13 of the downstream node. The TestStatusFailure message is a message for notifying the upstream node that reception of the Test message has failed when the downstream node does not receive the Test message for a certain period.

  “VERIFY # ID Class” (e) includes “VerifyId” (ea), which is an identifier of topology detection processing. This “VerifyId” (ea) is also used for Test messages, TestStatusSuccess messages, etc., and even if multiple topology detection processes are executed simultaneously between the same upstream node and downstream node, It is possible to identify which topology detection process is performed by VerifyId ”(ea).

  FIG. 11 shows the data structure of the Test message. The Test message is a message sent via the data channel from the interface (upstream node interface) that is the target of topology detection, and is “IP Header” (a), “Common Header etc” (b), “VERIFY # Data items of “ID Class” (e) and “LOCAL # INTERFACE # ID Class” (f) are included.

  “IP Header” (a), “Common Header etc” (b), and “VERIFY # ID Class” (e) are as described above. “LOCAL # INTERFACE # ID Class” (f) includes “InterfaceId” (fa), and “InterfaceId” (fa) is the interface ID of the upstream node to which this Test message is transmitted.

  FIG. 12 shows the data structure of the TestStatusSuccess message. The TestStatusSuccess message is a message that the downstream node that has successfully received the Test message returns to the upstream node through the control channel, and includes “IP Header” (a), “Common Header etc” (b), “LOCAL # INTERFACE #ID Class ”(f),“ REMOTE # INTERFACE # ID Class ”(g), and“ VERIFY # ID Class ”(e).

  “IP Header” (a), “Common Header etc” (b), and “VERIFY # ID Class” (e) are as described above. “InterfaceId” (fa) included in “LOCAL # INTERFACE # ID Class” (f) is the interface ID of the downstream node from which the Test message transmitted from the upstream node is received. “InterfaceId” (ga) included in “REMOTE # INTERFACE # ID Class” (g) is the interface ID of the upstream node (“Local # INTERFACE # ID Class” included in the Test message “ InterfaceId ”).

  Next, the flow of the topology detection process according to the first embodiment will be described. First, an outline of the topology detection process will be described, and then the details will be described.

  FIG. 13 is a sequence diagram illustrating an outline of the flow of the topology detection process according to the first embodiment. Here, as an example, three data channels Dch1 to Dch3 whose topology is not detected are provided between the upstream node and the downstream node, and the topology detection processing of these three data channels will be described.

  The data channel Dch1 corresponds to the output side interface ID # 1 of the upstream node, and corresponds to the input side interface ID # 2 of the downstream node. The data channel Dch2 corresponds to the interface ID # 2 on the output side of the upstream node, and corresponds to the interface ID # 3 on the input side of the downstream node. The data channel Dch3 corresponds to the interface ID # 3 on the output side of the upstream node, and corresponds to the interface ID # 1 on the input side of the downstream node.

  The upstream node transmits a BeginVerify message indicating the start of the topology detection process to the downstream node via the control channel, and the downstream node returns a BeginVerifyAck message as an acknowledgment to the upstream node via the control channel. Thereby, VerifyInterval (= 100 ms) and Number of Data Links (= 3) are notified from the upstream node to the downstream node, and VerifyDeadInterval (900 ms) and VerifyId (= 1) are notified from the downstream node to the upstream node.

  Subsequently, as shown in FIG. 13A, the upstream node selects the lowest number # 1 of the interface ID, and from the output port (interface # 1) of this interface ID # 1, the Test message ( Send Test (1)). In this case, VerifyId of the Test message is set to 1, and InterfaceId is set to 1.

  The downstream node also selects the number # 1 with the smallest interface ID, terminates the interface # 1, and attempts to receive a Test message from the interface # 1.

  However, in this case, since the Test message is not terminated (that is, received) by the control signal termination unit 14 via the O / E conversion unit 15 in the downstream node, the TestStatusSuccess message is not returned from the downstream node to the upstream node. The upstream node repeats sending the Test message a predetermined number of times at the time interval VerifyInterval.

  After sending the BeginVerifyAck message, the downstream node sets the 1-channel monitoring timer to a time of, for example, VerifyInterval (100 ms) × 3, and if it does not receive a Test message until this 1-channel monitoring timer times out, it times out Thus, as shown in FIG. 13B, the interface ID is changed to the next lowest interface ID # 2.

  As a result, the downstream node can terminate (receive) the Test message. Upon receiving the Test message, the downstream node transmits a TestStatusSuccess message shown in FIG. 10 to the upstream node. The InterfaceId of LOCAL # INTERFACE # ID of this TestStatusSuccess message is set to # 2, and the InterfaceId of REMOTE # INTERFACE # ID is set to # 1 (see FIG. 12).

  Further, the downstream node stores the interface connection relationship in the data channel management table of its own topology DB 20. That is, the topology detection presence / absence of the data channel management data corresponding to the interface ID # 2 of the data channel management table is set to 1, and # 1 is set to the remote interface ID (see FIG. 7).

  Upon receiving the TestStatusSuccess message from the downstream node, the upstream node returns a TestStatusAck message to the downstream node, and stores the interface connection relationship in the data channel management table of its own topology DB 20. That is, the topology detection presence / absence of the data channel management data corresponding to interface # 1 is set to 1, and the value # 2 of InterfaceId of LOCAL # INTERFACE # ID of the TestStatusSuccess message is set to the remote interface ID.

  Subsequently, as shown in FIG. 13C, the upstream node selects the next lowest numbered interface ID # 2, and transmits a Test message (Test (2)) from the interface # 2. On the other hand, the downstream node selects the lowest-numbered interface ID (in this case, interface # 1) from the interfaces other than the interface # 2 whose connection relation has already been found, terminates, and sends a test message from this interface # 1. Try to receive.

  Again, the receiving node cannot receive the Test message. Therefore, the receiving node selects and terminates the next lowest numbered interface # 3 among the interfaces except for the interface # 2, as shown in FIG. 13D, due to the timeout of the 1-channel monitoring timer. Attempt to receive Test message from # 3.

  In this case, since the reception is successful, the TestStatusSuccess message and the TestStatusAck message are exchanged and the connection relation to the topology DB 20 is registered.

  Next, as shown in FIG. 13E, the upstream node selects the next lowest interface ID # 3 and transmits a Test message (Test (3)) from the interface # 3. On the other hand, the downstream node selects and terminates the lowest-numbered interface ID (in this case, interface # 3) from the interfaces other than the interfaces # 1 and # 2 whose connection relations have already been found. Attempt to receive a Test message.

  Also in this case, since the reception is successful, the TestStatusSuccess message and the TestStatusAck message are exchanged and the connection relation to the topology DB 20 is registered.

  As a result, the topology detection processing for the number of links (= 3) is completed, and the topology detection processing in both nodes ends.

  In this way, the connection relationship between the interface of the upstream node and the interface of the downstream node is detected and stored in the topology DB 20 of both the upstream node and the downstream node.

  Next, details of the processing of this sequence will be described with reference to the block diagram of FIG. 4 and the sequence diagrams of FIGS.

  In the following description, the reference numeral “A” is appended to the reference numerals in FIG. 4 for the constituent elements of the upstream node, and the reference signs “B” are attached to the reference numerals of the constituent elements in the downstream node after the reference numerals in FIG. ". For example, the LMP control unit 14 of the upstream node becomes “LMP control unit 14A”, and the control channel IF unit 12 of the downstream node becomes “control channel IF unit 12B”. The same applies to the description of other embodiments which will be described later.

  The command control unit 11A of the upstream node gives the data channel registration request input by the administrator to the LMP control unit 13A. This data channel registration request includes the interface ID of the data channel to be registered.

  The LMP control unit 13A determines a control channel ID corresponding to the specified interface ID included in the data channel registration request based on the data channel management table stored in the topology DB 20A. When there are a plurality of interface IDs specified by the data channel registration request, a control channel ID corresponding to each interface ID is determined (S1 in FIG. 14).

  Here, for easy understanding, interface IDs # 1 to # 3 of upstream nodes are designated, and the data channels Dch1 to Dch3 corresponding to these three interface IDs # 1 to # 3 are all the same downstream. Assume that it is connected to a node. Therefore, the data channels Dch1 to Dch3 are all under the control of the same control channel (referred to as control channel ID # 1). However, the present invention is not limited to this, and it goes without saying that the present invention can also be applied when a data channel connected to a different downstream node is designated.

  Referring to FIG. 13, the LMP control unit 13A first selects the lowest-numbered interface # 1, and transmits a Test message to the data channel Dch1 corresponding to this interface, so that the data channel Dch1 is transmitted to the optical transmission IF unit 18A. Give a termination request for. Thus, the optical multiplexer 18aA (see FIG. 6) corresponding to the data channel Dch1 in the optical transmission IF unit 18A is set to select and output the optical signal input from the O / E conversion unit 15A.

  Next, the LMP control unit 13A creates a BeginVerify message for starting topology detection and gives a BeginVerify message transmission request to the control channel IF unit 12A. This transmission request includes the created BeginVerify message and control channel ID # 1 (S2).

  The control channel IF unit 12A transmits a BeginVerify message to the downstream node through the control channel with the control channel ID # 1 (control channel # 1) according to the request of the LMP control unit 13A (S3). The transmitted BeginVerify message is received by the control channel IF unit 12B of the downstream node.

  Therefore, referring to FIG. 16 showing the processing procedure (part 1) of the downstream node, the control channel IF unit 12B receives the BeginVerify message and gives a reception notification of the BeginVerify message to the LMP control unit 13B (S21).

  The LMP control unit 13B extracts the number of data channels and the interface ID (data channel) managed by the control channel that has received the BeginVerify message from the control channel management data (see FIG. 8) in the topology DB 20B (S22). Here, the number of data channels 3 and interface IDs # 1 to # 3 are extracted. Then, the LMP control unit 13B provides a control signal for terminating the interface to the optical reception IF unit 17B in order to terminate the interface # 1 having the smallest interface ID # 1 among the extracted interface IDs.

  Based on the control signal from the LMP control unit 13B, the output destination of the SEL 17cB corresponding to the interface # 1 of the optical reception IF unit 17B is set to MUX 17dB, and the MUX 17dB selects and outputs the optical signal from the SEL 17cB (see FIG. 5). Is set as follows.

  Further, the LMP control unit 13B creates a BeginVerifyAck message for notifying that the preparation for topology detection has been completed, requests the control channel IF unit 12B to send a message (S23), and sets the time Tch to the 1-channel monitoring timer. The timer is set and this timer is started (S24). The time Tch of the one-channel management timer is set to a time (100 ms × 3 = 300 ms) that is three times the VerifyInterval included in the BeginVerify message, for example.

  In response to a message transmission request from the LMP control unit 13B, the control channel IF unit 12B transmits a BeginVerifyAck message to the upstream node using the control channel # 1 (S25).

  Returning to FIG. 14, when receiving the BeginVerifyAck message from the downstream node, the control channel IF unit 12A gives a reception notification to the LMP control unit 13A (S4). When receiving the reception notification, the LMP control unit 13A creates a Test message (Test (1)) and requests the control signal termination unit 14A to transmit (S5). As a result, the Test message is transmitted from the control signal termination unit 14A to the downstream node via the optical transmission IF unit 18A (S6).

  Referring again to FIG. 16, the Test message transmitted from the upstream node is received by the interface # 2 of the downstream node (S26). On the other hand, the optical reception IF unit 17B is set to terminate the interface # 1. For this reason, the optical signal received by the optical reception IF unit 17B is not given to the O / E conversion unit 15B, and therefore no reception notification is given from the control signal termination unit 14B to the LMP control unit 13B.

  The upstream node transmits the Test message a plurality of times at the time interval VerifyInterval, but none of the Test messages is given to the O / E conversion unit 15B, and the LMP control unit 13B receives the reception notification from the control signal termination unit 14B. It will not be. For this reason, the one-channel monitoring timer times out (YES in S27), and the LMP control unit 13B sets the optical reception IF unit 17B to terminate the next lowest numbered interface # 2 among the interfaces whose topology has not been detected. Set (YES in S28, S29).

  If the number of test messages transmitted from the upstream node is n times (n is an integer of 2 or more), the time Tch set in the 1-channel monitoring timer is set to Tch <n × VerifyInterval. Therefore, while the upstream node is transmitting a Test message to a certain data channel, the one-channel monitoring timer of the downstream node times out, and the downstream node switches to the next data channel.

  Then, the LMP control unit 13B sets a one-channel monitoring timer (S30) and tries to receive the Test message in the same manner as described above.

  Next, the processing procedure (part 2) of the downstream node is moved to FIG. 17, and the Test message received by the optical reception IF unit 17B is transferred to the LMP control unit 13B via the O / E conversion unit 15B and the control signal termination unit 14B. When given (S41), the LMP control unit 13B updates the data channel management table of the topology DB 20B based on the Test message (S42).

  That is, the LMP control unit 13B reads the data channel management data corresponding to the interface ID # 2 that requested termination from the optical reception IF unit 17B from the topology DB 20B, and changes the topology detection presence / absence of the read data channel management data to 1. In the remote interface ID, the node ID included in the Common Header etc (FIG. 11B) of the Test message and the InterfaceId (# 1) of Local # Interface # ID (FIG. 11F) are written.

  Subsequently, the LMP control unit 13B searches the control channel management table of the topology DB 20B by the interface ID and determines whether there is an interface ID for which no topology is detected (S43). If there is an interface ID whose topology has not been detected, the LMP control unit 13B extracts the interface ID of the lowest number (# 1 in the example of FIG. 13) among them as described above (S44). ) A data channel termination request is given to the optical reception IF unit 18B, and the time is set in the 1-channel monitoring timer.

  Thereafter, the LMP control unit 13B creates a TestStatusSuccess message for the Test message received in step S41, and requests the control channel IF unit 12B to transmit (S46).

  As a result, the control channel IF unit 12B transmits a TestStatusSuccess message (S47), and waits for reception of a TestStatusAck message from the upstream node. InterfaceID # 2 of the downstream node is written in InterfaceId of LOCAL # INTERFACE # ID of this TestStatusSuccess message, and InterfaceId (# 1) included in LOCAL # INTERFACE # ID of Test message is written in InterfaceId of REMOTE # INTERFACE # ID ) Is written. Thereafter, the control channel IF unit 12B receives the TestStatusAck message from the upstream node (S48).

  Even when there is no interface ID whose topology is not detected in step S43, the TestStatusSuccess message for the Test message in step S41 is transmitted to the upstream node, and the TestStatusAck message transmitted from the upstream node is received.

  Similar processing is repeated for other interface IDs.

  Returning to FIG. 15 showing the processing procedure (part 2) of the upstream node, when receiving the TestStatusSuccess message from the upstream node, the control channel IF unit 12A of the upstream node gives a reception notification to the LMP control unit 13A (S7). The LMP control unit 13A updates the data channel management table in the topology DB 20A (S8).

  That is, the LMP control unit 13A reads the data channel management data corresponding to the interface ID # 1 that requested termination from the optical transmission IF unit 18A from the topology DB 20A, and changes the topology detection presence / absence of the read data channel management data to 1. Then, the node ID included in the Common Header etc of the TestStatusSuccess message and the InterfaceId (= # 1) of LOCAL # INTERFACE # ID are written in the remote interface ID.

  Subsequently, the LMP control unit 13A creates a TestStatusAck message and requests transmission to the control channel IF unit 12A (S9). The control channel IF unit 12A transmits a TestStatusAck message to the downstream node according to the transmission request (S11).

  Thereafter, the LMP control unit 13A extracts the next interface ID whose topology has not been detected (S10). The same process is repeated for the extracted interface ID.

  In FIG. 15, when the topology detection processing is completed for the interfaces of “Number of Data Links” in the BeginVerify message, the LMP control unit 13A creates an EndVerify message (S12), and the control channel IF unit 12A Transmit to the downstream node (S13). Thereafter, the EndVerifyAck message transmitted from the downstream node is received by the control channel IF unit 12A (S14), the reception notification is given to the LMP control unit 13A, and the topology detection process is completed.

  Further, in FIG. 17, when the topology detection processing is completed for the interfaces corresponding to the “Number of Data Links” of the BeginVerify message, the LMP control unit 13B waits for the reception of the EndVerify message (S49) and creates an EndVerifyAck message. The control channel IF unit 12B transmits this to the upstream node (S51). As a result, the topology detection process ends.

Returning to FIG. 16, there is no interface ID whose topology is not detected in step S28 (NO in S28), and the “Number of” included in the BeginVerify message.
When the topology detection processing for the number of “Data Links” has not been completed, the LMP control unit 13B creates a TestStatusFailure message (S31), and the control channel IF unit 12B transmits the TestStatusFailure message to the upstream node ( S32) The upstream node LMP control unit 13A receives the TestStatusFailure message to know that the topology detection has failed.

  In the present embodiment, the method of selecting an interface in order from the interface having the lowest-numbered interface ID has been described for both the upstream node and the downstream node. However, the interface selection method is not limited to this. You may select in order from a small thing, and may select at random. The same applies to a third embodiment to be described later.

  Further, two, three, etc., may be provided as long as the number of control signal termination units 14 is smaller than the number of data channels. However, one with the lowest cost is preferred. The same applies to the O / E converter 15. The same applies to the following second to fourth embodiments.

  In the second embodiment of the present invention, when a downstream node attempts to receive a Test message through a certain data channel, when an optical signal is detected in another data channel, the other data in which the optical signal is detected is detected. The channel is a candidate for the next data channel to be terminated. Thereby, the topology detection process can be speeded up.

  In the second embodiment, the upstream node transmits the dummy light to the downstream node in advance by the data channel scheduled to transmit the Test message next while transmitting the Test message by a certain data channel, Next, it is also possible to notify the downstream node in advance of the data channel for transmitting the Test message. Thereby, the topology detection process can be further speeded up.

  FIG. 18 is a block diagram showing a configuration of a node according to the second exemplary embodiment of the present invention. Constituent elements that are the same as or similar to the node according to the first embodiment shown in FIG. 4 are given the same reference numerals, and detailed descriptions of those having the same configuration and function are omitted. The same applies to other embodiments described later.

  The difference from the node according to the first embodiment shown in FIG. 4 is that a topology detection order control unit 19 is added. When the topology detection order control unit 19 detects an optical signal in a data channel of which topology is not detected when the own node is a downstream node, the topology detection order control unit 19 assigns the interface ID to the topology detection candidate channel queue in the order of the interface in which the optical signal is detected. The data channel to be subjected to the next topology detection is determined in the order of the queued interface IDs.

  The optical reception IF unit 17 according to the second embodiment includes a control device, a photodetector, and a register in addition to the SEL and MUX of the optical reception IF unit 17 according to the first embodiment.

  A photodetector is provided for each data channel and detects whether an optical signal is received on each data channel. When each optical detector detects an optical signal, it provides a detection signal (electric signal) to the control device.

  The register has a detection flag provided for each data channel (input interface). Each detection flag consists of 1 bit, for example. The LMP control unit 13 sets the detection flag.

  The detection flag indicates whether or not the topology detection processing of the data channel corresponding to the detection flag has been completed. When “1” is set in the detection flag, the topology detection processing of the data channel corresponding to the detection flag is completed. On the other hand, when “0” is set in the detection flag, the topology detection processing of the data channel corresponding to the detection flag is not completed.

  The control device is notified of the currently terminated interface ID from the LMP control unit 13. When the control device receives the detection signal from the photodetector, the interface notified from the LMP control unit 13 whether or not the data channel (interface) corresponding to the photodetector to which the detection signal is applied is currently terminated. Judgment is made based on the ID, and whether the interface is a topology undetected interface is judged based on the detection flag of the register.

  If the interface corresponding to the photodetector is not an interface that is currently terminated and an interface that has not been detected as a topology, the controller detects the topology as the interface that should be terminated next. Queuing to the topology detection candidate channel queue (hereinafter simply referred to as “queue”) of the forward control unit 19.

  FIG. 19 shows the data structure of the queue of the topology detection order control unit 19. The queue has a pointer list 19a including a queue head pointer and a queue tail pointer, and interface lists 19b and 19c.

  The queue head pointer of the pointer list 19a is a pointer that points to the interface list 19a at the head of the queue. When the interface ID is not queued in this queue, there is no interface list. Therefore, a value that does not function as a pointer such as NULL is written in the queue head pointer. The queue tail pointer is a pointer that points to the interface list linked to the tail. When the interface list does not exist, a value such as NULL is written to this queue tail pointer.

  The interface lists 19b and 19c include a link list previous pointer that points to an interface list or pointer list 19a linked adjacently in front of itself, a link next pointer that points to an interface list linked adjacently behind itself, and Interface ID. When there is no interface list linked to the rear side of itself, a value such as NULL is written in the link next pointer. Other interface lists (not shown) have the same configuration.

  When a new interface ID is queued, the interface list having this new interface ID is linked to the tail of the queue.

  The LMP control unit 13 extracts the interface ID of the head interface list (interface list pointed to by the queue head pointer) from the interface IDs queued in the queue, and terminates the extracted interface ID. The IF unit 170 is controlled. When the interface ID is extracted, the interface list having the extracted interface ID is deleted (erased), and the interface list linked adjacently behind it becomes the top interface list.

  The optical transmission IF unit 18 includes a light emitting element for each data channel in addition to the MUX of the optical transmission unit 18 according to the first embodiment shown in FIG. The light emitting element emits light according to a command from the LMP control unit 13 and transmits an optical signal to the downstream node. This light is an optical signal that does not have a predetermined format such as a Test message, and is so-called dummy light.

  Hereinafter, the outline of the topology detection process according to the second embodiment will be described, and then the details thereof will be described.

  FIG. 20 is a sequence diagram showing an outline of the flow of the topology detection process according to the second embodiment. Here, a state in which the downstream node B receives the Test message from the two upstream nodes A and C and executes the topology detection processing is shown.

  In FIG. 20A, the Test message is transmitted from the interface # 1 of the upstream node A to the interface # 2 of the downstream node B, while the downstream node B terminates the data channel of the interface # 1 and receives the Test message. Indicates the attempted state.

  In this state, the downstream node B detects an optical signal on the data channel of interface # 2. Therefore, the downstream node B determines whether the interface # 2 that has detected the optical signal has already detected the topology and whether it is a terminated interface, and if the topology has not been detected and is not a terminated interface. Queues interface # 2 in the queue.

  After upstream node A transmits a Test message, as shown in FIG. 20A, when upstream node C transmits a Test message from interface # 1, downstream node B transmits an optical signal (Test Message). Therefore, the downstream node B also queues interface # 4 at the end of the queue.

  In the state shown in FIG. 20A, since the downstream node B does not receive the Test message at the terminated interface # 1, the one-channel monitoring timer times out. Due to this timeout, the downstream node B extracts the interface list (interface list of interface # 2) queued at the head of the queue and deletes the extracted interface list from the queue.

  Then, the downstream node B terminates the extracted interface # 2. As a result, the Test message from the upstream node A is received by the downstream node B as shown in FIG. As a result, the topology is detected, and the mapping between the interface # 1 of the upstream node A and the interface # 2 of the downstream node B is registered in the respective topology DBs of the upstream node A and the downstream node B.

  The upstream node A transmits a dummy light to the downstream node B from the interface # 2 that transmits the Test message next while transmitting the Test message from the interface # 1. As a result, the downstream node B detects light at the interface # 3 and queues the interface # 3 at the end of the queue.

  On the other hand, since it is the interface # 4 that is queued at the head of the queue, the downstream node B next terminates the interface # 4. Thereby, as shown in FIG. 20C, the Test message from the upstream node C is received by the downstream node B, and the topology is detected. The mapping between the interface # 1 of the upstream node C and the interface # 4 of the downstream node B is registered in the topology DB 20 of each of the upstream node C and the downstream node B.

  Next, as illustrated in FIG. 20D, the downstream node B terminates the interface # 3 queued in the queue by receiving the dummy light. On the other hand, when the topology detection processing of the interface # 1 is completed, the upstream node A immediately switches the dummy light transmitted from the interface # 2 to the Test message, and transmits the Test message to the downstream node B.

  As a result, the downstream node B receives the Test message from the upstream node A at the interface # 3, and the topology is detected.

  Such processing is repeated, and the topology detection processing is executed between the upstream nodes A and C and the downstream node B.

  Next, details of the processing sequence in the second embodiment will be described with reference to the block diagram of FIG. 18 and the sequence diagrams of FIGS.

  In the sequence diagrams of FIGS. 21 to 23, the same processes as those in FIGS. 14 to 17 of the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted. Further, as mentioned above, the reference numeral “A” is appended to the reference numerals in FIG. 18 for the constituent elements of the upstream node A, and the reference numerals in FIG. Is denoted by “C”, and the symbols of each component of the downstream node B are denoted by “B” after the symbols of FIG.

  Referring to FIG. 21, similar to the first embodiment, after sending the BeginVerify message and receiving the BeginVerifyAck message (not shown), the LMP control unit 13A of the upstream node A creates a Test message (S5), and the control signal The termination unit 14A transmits the Test message to the downstream node B via the O / E conversion unit 15A and the optical transmission IF unit 18A (S6).

  Subsequently, the LMP control unit 13A searches for control channel management data corresponding to the control channel ID from the control channel management table of the topology DB 20A, and is the youngest among the data channels whose topology has not been detected in the searched control channel management data. The interface ID of the number is extracted (S61). If this interface ID exists (YES in S62), a dummy optical transmission request from this interface is given to the optical transmission IF unit 18A. The optical transmission IF unit 18A transmits dummy light according to the transmission request (S63). On the other hand, when the interface ID does not exist, the LMP control unit 13A does not give a dummy light transmission request.

  When the TestStatusSuccess message is returned from the downstream node B in response to the transmitted Test message, the processes of Steps S5 and S6 are executed for the interface (data channel) through which the dummy light is transmitted. Switch to Test message.

  The transmission of the Test message and the transmission of the dummy light are executed in the same manner for other interfaces that perform topology detection. The same processing is also executed at the upstream node C.

  On the other hand, referring to FIG. 22, in the downstream node B, after receiving the BeginVerify message and transmitting the BeginVerifyAck message (not shown), the optical reception IF unit 17B receives the optical signal (Test message or dummy light) (S71). The control device of the optical reception IF unit 17B confirms whether the interface (data channel) that received the optical signal is an interface whose topology has not been detected and is not terminated (S72).

  If the interface that has received the optical signal has not detected topology (that is, the detection flag corresponding to the interface is “0”) and is not terminated, the control device of the optical reception IF unit 17B uses this interface ID as the topology. The queue is queued in the detection order control unit 19B (S73). For example, in FIG. 20A, the interface ID # 2 receiving the Test message from the upstream node A is queued.

  If the interface that has received the optical signal has already been topology detected (that is, if the detection flag corresponding to the interface is “1”), this interface ID is not queued. Also, if the interface that received the optical signal is a terminated interface, this interface ID is not queued, but the Test message in step S41 in FIG. 23 is received, and the processing (step S42 and subsequent steps in FIG. (Described later) is executed.

  The LMP control unit 13B checks whether the interface ID is queued in the queue of the topology detection order control unit 19B when the one-channel monitoring timer times out (S24, S27) (S74).

  If the interface ID is queued (YES in S74), the LMP control unit 13B extracts the interface ID that is queued at the head, and the interface of the optical reception IF unit 17B corresponding to the extracted interface ID ( The data channel is terminated (S75). In FIG. 20B, the queued interface ID # 2 interface is terminated. The interface list of the interface ID extracted from the queue is deleted (erased) from the queue, and the interface list subsequent to the deleted interface list is sequentially advanced in the head direction.

  After termination of the interface, a one-channel monitoring timer is set (S30), and a Test message is received.

  The interface ID # 4 that has received the Test message from the upstream node C in FIG. 20A is also queued in the same manner, and after the topology detection processing of the interface ID # 2, as shown in FIG. Is taken out of and terminated. Subsequently, the interface ID # 3 that has received the dummy light is also taken out of the queue and terminated (see FIG. 20D).

  On the other hand, if the interface ID is not queued in the queue in step S74 (NO in S74), the processes in steps S28 to S32 described in the first embodiment are executed.

  Moving to FIG. 23, when an optical signal (that is, a Test message) is received at the terminated interface of the downstream node B (S41), the LMP control unit 13B performs the data channel of step S42 described in the first embodiment. Execute management table update processing. Subsequently, the LMP control unit 13B determines whether an interface ID is queued in the queue (S81). This determination is the same as the processing in step S74 in FIG.

  When the interface ID is queued (YES in S81), the LMP control unit 13B extracts the top interface ID and terminates this interface (data channel) (S82). On the other hand, if the interface ID is not queued (NO in S81), the processes in steps S43 and S44 described in the first embodiment are executed. Thereafter, the processes of steps S45 to S48 are executed.

  As a result, when a downstream node detects an optical signal (Test message or dummy light) in another data channel while detecting the topology of a data channel, priority is given to the topology detection of this other data channel. Thus, even when one electrical termination function (O / E conversion unit 15 and control signal termination unit 14) is used, topology detection can be performed in a short time.

  In the third embodiment of the present invention, the optical switch unit 16 switches the optical signal from the optical reception IF unit 17 to the O / E conversion unit 18 and switches the optical signal from the O / E conversion unit 18. Thus, it is given to the optical transmission IF unit 17.

  FIG. 24 is a block diagram showing the configuration of an OXC node according to the third embodiment of the present invention. In this embodiment, as in the previous embodiment, the OXC node includes a command IF unit 11, a control channel IF unit 12, an LMP control unit 13, a control signal termination unit 14, an O / E conversion unit 15, and an optical reception IF unit 17. , An optical switch unit 16, an optical transmission IF unit 18, and a topology DB 20.

  The command IF unit 11, topology DB 20, control channel IF unit 12, control signal termination unit 14, O / E conversion unit 15, LMP control unit 13 and topology DB 20 are the same as those in the first embodiment shown in FIG. Therefore, detailed description thereof is omitted.

  The optical reception IF unit 17 does not include the optical selectors (SELs 17a to 17c) and the optical multiplexer (MUX 17d) included in the optical reception IF unit 17 according to the first embodiment. Further, the optical transmission IF unit 18 does not include the optical multiplexers (MUXs 18a to 18c) included in the optical transmission IF unit 18 according to the first embodiment.

  The optical switch unit 16 has an output line to the O / E conversion unit 15 in addition to an output line to the optical transmission IF unit 18 (data channels Dch1 to Dch3). Then, the optical switch unit 16 outputs, to the O / E conversion unit 15, the data channel optical signal to be terminated for topology detection processing, out of the data channel optical signal input via the optical reception IF unit 17. To switch. As a result, the test message can be terminated at the downstream node.

  The optical switch unit 16 includes an input line from the O / E conversion unit 15 in addition to the input lines from the optical reception IF unit 17 (data channels Dch1 to Dch3). Then, the optical switch unit 16 performs switching so that the optical signal input from the O / E conversion unit 15 is output to any one of the output lines to the optical transmission IF unit 18. As a result, the Test message can be transmitted in the upstream node.

  Note that such switching control of the optical switch unit 16 is performed by the LMP control unit 13.

  In the topology detection processing according to the third embodiment, the test message is switched from the O / E converter 15 by the optical switch unit 16 to the optical transmission IF unit 18 at the upstream node, and at the downstream node. This is the same as the first embodiment except that the received Test message is switched by the optical switch unit 16 and given to the O / E conversion unit 15. Therefore, the details of the topology detection process are omitted.

  Also according to the present embodiment, the control signal termination unit 14 and the O / E conversion unit 15 that terminate the optical signal may be smaller than the number of data channels, thereby reducing the apparatus cost.

  In the fourth embodiment of the present invention, similarly to the third embodiment, the optical switch unit 16 switches the optical signal from the optical reception IF unit 17 and supplies it to the O / E conversion unit 15 for O / E conversion. The optical signal from the unit 15 is switched and supplied to the optical transmission IF unit 18, and similarly to the second embodiment, the topology detection order control unit 19 is provided to queue the interface ID that has received the optical signal. Is.

  FIG. 25 is a block diagram showing the configuration of an OXC node according to the fourth embodiment of the present invention. The OXC node includes a command IF unit 11, a control channel IF unit 12, an LMP control unit 13, a control signal termination unit 14, an O / E conversion unit 15, an optical reception IF unit 17, an optical switch unit 16, and an optical transmission IF unit 18. The topology detection order control unit 19 and the topology DB 20 are included.

  The command IF unit 11, topology DB 20, control channel IF unit 12, control signal termination unit 14, O / E conversion unit 15, LMP control unit 13, and topology DB 20 are the same as those in the first embodiment shown in FIG. Therefore, detailed description thereof is omitted. The topology detection order control unit 19 is the same as that of the second embodiment shown in FIG. 18, and the optical switch unit 16 and the optical transmission IF unit 18 are the same as those of the third embodiment shown in FIG. Since they are the same, detailed description thereof is omitted.

  The optical reception IF unit 17 does not include the optical selectors (SELs 17a to 17c) and the optical multiplexer (MUX 17d) included in the optical reception IF unit 17 according to the first embodiment.

  On the other hand, the optical reception IF unit 17 includes a control device, a photodetector, and a register (detection flag), similarly to the optical reception IF unit 17 of the second embodiment. Similarly to the second embodiment, the control device determines the topology of the interface from which the optical signal is detected by the photodetector based on the termination / non-termination of the interface and the detection flag of the register given from the LMP control unit 13. It is determined whether or not the interface ID is queued to the detection order control unit 19. When the interface is non-terminal and the detection flag is “0”, the interface ID is queued.

  The LMP control unit 13 extracts the interface ID queued at the head of the queue of the topology detection order control unit 19 and terminates the data channel (interface) corresponding to the extracted interface ID. Control switching.

  As described above, the topology detection processing according to this embodiment is performed by the topology detection order control unit 19 and the optical reception IF unit 17 in the same manner as in the second embodiment, and is the same as in the third embodiment. Thus, the optical switch unit 16 switches the optical signal from the optical reception IF unit 17 to the O / E conversion unit 15 and the optical signal from the O / E conversion unit 15 to the optical transmission IF unit 18. .

  Also according to the present embodiment, the control signal termination unit 14 and the O / E conversion unit 15 that terminate the optical signal may be smaller than the number of data channels, thereby reducing the apparatus cost. Further, according to the present embodiment, it is possible to increase the speed of the topology detection process.

  Similar to the optical transmission IF unit 18 of the second embodiment, the optical transmission IF unit 18 includes a light emitting element, and can transmit dummy light to a data channel on which a Test message is to be transmitted next. Thereby, the topology detection process can be further accelerated.

  The fifth embodiment of the present invention is a response signal to the Test message in the upstream node, whereas in the first and second embodiments, the timer for monitoring the reception of the TEST message is held in the downstream node. Holds a timer to monitor TestStatusSuccess message reception on the control channel. Thereby, the topology detection of a plurality of data channels can be performed at high speed by one electrical termination function.

 The OXC node configuration according to the fifth embodiment is the same as that corresponding to the first embodiment, and the configuration shown in FIG. 4 is possible. However, unlike the first embodiment, the upstream node has a timer function that waits for reception of a TestStatusSuccess message for a certain period of time.

 If the TestStatusSuccess message on the control channel, which is a response signal to the Test message, is not received within a certain time, the data channel to be terminated is changed to another data channel. By repeating such processing in the upstream node, topology detection becomes possible.

  That is, when the upstream node does not receive a response signal on the control channel for the Test message within a certain period of time, the data channel terminated by the LMP control unit 13 is switched to any data channel for which other topology detection has not been completed. In this configuration, control is performed. Thus, in response to an instruction from the LMP control unit 13, the optical transmission IF unit 18 functions to transmit an optical signal to a designated data channel, and detects a large number of data channel topologies with at least one electrical termination function. It can be realized.

  FIG. 26 is a sequence diagram illustrating an outline of the flow of the topology detection process according to the fifth embodiment. Here, as an example, assuming that three data channels Dch1 to Dch3 whose topology is not detected are provided between the upstream node and the downstream node as in the previous embodiment, the topology of these three data channels is assumed. The detection process will be described.

  The data channel Dch1 corresponds to the output side interface ID # 1 of the upstream node, and corresponds to the input side interface ID # 2 of the downstream node. The data channel Dch2 corresponds to the interface ID # 2 on the output side of the upstream node, and corresponds to the interface ID # 3 on the input side of the downstream node. The data channel Dch3 corresponds to the interface ID # 3 on the output side of the upstream node, and corresponds to the interface ID # 1 on the input side of the downstream node.

  In FIG. 26, the upstream node transmits a BeginVerify message indicating the start of the topology detection process to the downstream node through the control channel, and the downstream node returns a BeginVerifyAck message as a confirmation response to the upstream node through the control channel. Thereby, VerifyInterval (= 100 ms) and Number of Data Links (= 3) are notified from the upstream node to the downstream node, and VerifyDeadInterval (900 ms) and VerifyId (= 1) are notified from the downstream node to the upstream node.

  Subsequently, as shown in FIG. 26A, the upstream node selects the lowest number # 1 of the interface ID, and from the output port (interface # 1) of this interface ID # 1, the Test message ( Send Test (1)). In this case, VerifyId of the Test message is set to 1, and InterfaceId is set to 1.

  Further, as a feature of the present embodiment, when transmitting an Test message, the upstream node sets a one-channel monitoring timer to a time of, for example, VerifyInterval (100 ms) × 3, and until this one-channel monitoring timer times out (TO) During this period, the return of the TestStatusSuccess message that confirms the reception of the Test message from the downstream node is monitored.

  In the example of FIG. 26, since the interface ID # 3 is terminated as an initial state in the downstream node, the Test message (Test (1)) from the upstream node cannot be received. Therefore, the upstream node cannot receive the TestStatusSuccess message for confirming reception of the Test message (Test (1)) from the downstream node within the period of the one-channel monitoring timer. Therefore, the monitoring timer times out (TO).

  The upstream node switches the interface node to the next lowest interface ID # 2 as shown in FIG. 26B by the timeout (TO) of the monitoring timer, and sends a Test message (Test (2)). At this time, the Test message (Test (2)) can be received at the downstream node, so the TestStatusSuccess message is returned from the downstream node. At this time, the InterfaceId of LOCAL # INTERFACE # ID of the TestStatusSuccess message is set to # 3, and the InterfaceId of REMOTE # INTERFACE # ID is set to # 2.

  Further, the downstream node stores the connection relationship of the interfaces related to the data channel management table of its own topology DB 20. That is, the presence / absence of detection of topology of the data channel management data corresponding to the interface ID # 3 of the data channel management table is set to “1” indicating presence of detection, and # 2 is set to the remote interface ID.

  Upon receiving the TestStatusSuccess message from the downstream node, the upstream node returns a TestStatusAck message to the downstream node, and stores the interface connection relationship in the data channel management table of its own topology DB 20. That is, the topology detection presence / absence of the data channel management data corresponding to the interface # 2 is set to “1”, and the value # 3 of the InterfaceId of LOCAL # INTERFACE # ID in the TestStatusSuccess message is set to the remote interface ID.

  Subsequently, as shown in FIG. 26C, the upstream node selects the lower-numbered interface ID # 1 again and transmits a Test message (Test (1)) from the interface # 1. On the other hand, the downstream node selects the lowest-numbered interface ID (in this case, interface # 1) from the interfaces other than the interface # 3 whose connection relation has already been found, terminates, and sends a test message from this interface # 1. Try to receive.

  In this case, the receiving node cannot receive the Test message (Test (1)). Therefore, the transmission node selects and terminates the remaining interface # 3 except for the interfaces # 2 and # 1, as shown in FIG. 26 (D), due to the timeout of the 1-channel monitoring timer. Send message (3).

  In this case, since the reception is successful, the exchange of the TestStatusSuccess message and the TestStatusAck message and the registration of the connection relation to the topology DB 20 are performed in each of the downstream node and the upstream node.

  Next, as shown in FIG. 26E, the upstream node selects the remaining interface ID # 1, and transmits a Test message (Test (1)) from the interface # 1. On the other hand, the downstream node selects and terminates the remaining interface ID # 2 except for the interfaces # 3 and # 2 whose connection relation has already been found, and tries to receive the Test message from this interface # 2.

  Also in this case, since the reception is successful, the TestStatusSuccess message and the TestStatusAck message are exchanged and the connection relation to the topology DB 20 is registered.

  As a result, the topology detection processing for the number of links (= 3) is completed, and the topology detection processing in both nodes ends.

  In this way, the connection relationship between the interface of the upstream node and the interface of the downstream node is detected and stored in the topology DB 20 of both the upstream node and the downstream node.

  Next, details of the processing of this sequence will be described with reference to the node configuration of FIG. 4 and the sequence diagrams of FIGS.

  Since the fifth embodiment uses the same network configuration example as the first embodiment, description of the network configuration is omitted. For the description, each part of the OXC node uses the configuration shown in FIG. The present embodiment can be similarly realized in the OXC node configuration (see FIGS. 18, 24, and 25) in the other embodiments.

  First, in FIG. 27, the LMP control unit 13 receives a data channel registration request through the command IF control unit 11 for the data channel of the interface ID = 1 to 3 from the administrator, and starts the topology detection operation.

 At this time, the command IF control unit 11A of the upstream node OXC node A receives the data channel registration request input by the administrator, and the control channel IF unit 12 transmits a BeginVerify message to the downstream node OXC node B. To do. The operations so far (S1 to S3) are the same as those in the previous embodiments. The BeginVerify message transmitted from OXC node A in this way reaches OXC node B, which is a downstream node, as shown in FIG.

  Referring to FIG. 30, the control channel IF unit 12B of the OXC node B, which is the downstream node, notifies the received BeginVerify message to the LMP control unit 13B (S21). The LMP control unit 13B indexes the control channel management table shown in FIG. 8 stored in the topology database 20 by the control channel ID that has received the BeginVerify message, and extracts the number of data channels and the interface ID (S22).

 The data extracted from the control channel management table is as shown in FIG. 8 (data channel number = 3, interface ID # 1 = 1, interface ID # 2 = 2, interface ID # 3 = 3).

 Next, the LMP control unit 13B makes a termination request for the channel to the optical reception IF unit 17B in order to terminate the data channel (interface ID = 1) having the smallest number among the extracted interface IDs.

 The optical reception IF unit 17B in this embodiment switches the selector so that the optical signal with the interface ID = 1 flows into the O / E conversion unit 15B in order to terminate the notified data channel with the interface ID = 1. The LMP control unit 13B edits the BeginVerifyAck message for notifying that the preparation for topology detection is completed, and sends a message transmission request to the control channel IF unit 12B (S23). The format and setting information of the BeginVerifyAck message to be edited at this time are the same as those described for the first embodiment.

 Upon receiving the message transmission request, the control channel IF unit 12B transmits a message using the control channel (S25). In the first embodiment, the one-channel monitoring timer is started here, but in the fifth embodiment, the timer is not used in the downstream node because the timer is held in the upstream node (S90 in FIG. 27).

  The BeginVerifyAck message transmitted from OXC node B in this way reaches OXC node A as shown in FIG.

  Returning to FIG. 27, the control channel IF unit 12A of the upstream node OXC node A notifies the received BeginVerifyAck message to the LMP control unit 13A (S4). When notified of the BeginVerifyAck message, the LMP control unit 13A edits the TEST message and makes a transmission request for the TEST message to the control signal termination unit 14A at an interval of VerifyInterval [100 msec] (S5).

 At this time, the TEST message to be edited has the format shown in FIG. 11, and the setting information is shown enlarged on the right side of FIG. The interface ID (Interface # Id) set in this TEST message is an identifier assigned to the data channel to which the upstream node transmits the TEST message. In addition, the one-channel monitoring timer set in the downstream node in the first embodiment is started at this point in this embodiment (S90).

 Upon receipt of the TEST message transmission request, the control signal termination unit 14A inserts the TEST message, performs framing to the transmission format of the physical layer, and notifies the O / E conversion unit 15A (S6). The O / E conversion unit 15A converts the electrical signal into an optical signal, and transmits it to the data channel through the optical transmission IF unit 18.

  The TEST message transmitted from OXC node A in this way propagates on the data channel and reaches OXC node B. Note that the relationship between the termination data channel in the upstream node and the termination data channel in the downstream node in this state is as shown in FIG.

  In the state shown in FIG. 26, the OXC node B that is the downstream node does not receive the TEST message. In the first embodiment, a one-channel monitoring timer for monitoring reception of the TEST message is started in the downstream node, and the timer is not used in the upstream node. On the other hand, in the fifth embodiment, a one-channel monitoring timer for monitoring the reception of the TestStatusSuccess message at the upstream node is started (see S90 in FIG. 27).

  Moving to FIG. 28, since the upstream node does not receive the TestStatusSuccess message, the LMP control unit 13A detects the occurrence of a timeout of the 1-channel monitoring timer (S91, YES). In this embodiment, when a timeout occurs, the LMP control unit 13A indexes the control channel management table of FIG. 8 with the control channel, and extracts the next lowest data channel (interface ID = 2).

 The extracted data channel (interface ID = 2) is requested to terminate the channel to the optical transmission IF unit 18A. The optical transmission IF unit 18A terminates the notified data channel with the interface ID = 2, so that the optical signal with the interface ID = 2 passes through the O / E conversion unit 15A to the data channel with the interface ID = 2. The selector is switched so as to flow in as a signal.

 Next, the LMP control unit 13A edits the TEST message, requests the control signal termination unit 14A to transmit a TEST message (S93), and the control signal termination unit 14A sends the TEST message through the optical transmission IF unit 18A. (S94). Further, the LMP control unit 13A starts a one-channel monitoring timer (VerifyInterval [100 msec] × 3 times = 300 msec) (S95). The relationship between the termination data channel in the upstream node and the termination data channel in the downstream node in this state is as shown in FIG.

 In the state shown in FIG. 26B, similarly, the downstream node does not receive the TEST message, and therefore, a timeout of the one-channel monitoring timer that monitors reception of the TestStatusSuccess message that is a response message of the TEST message occurs in the upstream node. Also in this case, according to the flow of FIG. 28, the next young data channel (interface ID = 3) is terminated and the same processing is performed.

 The relationship between the termination data channel in the upstream node and the termination data channel in the downstream node in this state is as shown in FIG. In FIG. 26C, since the data channel terminated at the upstream node is the same as the data channel terminated at the downstream node, the OXC node B of the downstream node receives the TEST message. The description of the operation until the downstream OXC node B receives the TEST message and transmits the TestStatusSuccess message to the upstream OXC node A is the same as in the first embodiment described above. The TestStatusSuccess message transmitted from the OXC node B in this way reaches the OXC node A through the control channel as in the first embodiment.

  Referring to FIG. 29, the control channel IF unit 12A of the upstream node OXC node A notifies the LMP control unit 13A of the received TestStatusSuccess message (S7).

 The LMP control unit 13A indexes the control channel management table shown in FIG. 7 stored in the topology DB 20 based on the interface ID = 3 in the TestStatusSuccess message, and the topology detection presence = 1 (topology detected) and the remote interface ID = 1 (LOCAL # INTERFACE # ID: downstream node interface ID set in the TestStatusSuccess message) is set (S8). With this setting, the upstream node can identify the connection destination connected downstream of the data channel.

 Next, the LMP control unit 13A edits the TestStatusAck message as a response to the TestStatusSuccess message, and makes a message transmission request to the control channel IF unit 12A (S9). Therefore, a TestStatusAck message is transmitted from the control channel IF unit 12A to the downstream node OXC node B. Since this TestStatusAck message is the same as that in the above-described embodiment, further explanation is omitted.

  In this way, in the upstream node, the topology detection for the interface ID = 3 is completed. Next, in FIG. 29, the control unit 13A of the upstream node indexes the control channel management table by the control channel ID, and extracts the youngest interface ID from the topology undetected data channels (S96).

 In this embodiment, the data channel with interface ID = 1 is extracted. For this extracted interface ID = 1, a TEST message is sent out as in the first time (S97), and topology detection is performed. At the same time, a one-channel monitoring timer is set (S98). Since this topology detection method is the same as that already described, further description thereof is omitted. By performing the topology detection for all the interface IDs = 1 to 3 in this way, the topology detection between the OXC node A and the OXC node B is completed.

  As described above, in the first embodiment, the timer for monitoring the reception of the TEST message is held in the downstream node, but in this embodiment, the timer for monitoring the reception of the TestStatusSuccess message is held in the upstream node. Thereby, topology detection of a plurality of data channels can be performed by one electrical termination function.

  In the sixth embodiment, when the termination data channel is switched at a certain time by the monitoring timer in the upstream node, the optical signal is detected in a data channel different from the termination data channel in the downstream node, and the next topology detection is performed. It is intended for use. By providing a function of switching a data channel to be terminated to a data channel that detects an optical signal, high-speed topology detection is realized.

  FIG. 31 is a diagram showing a network configuration in application of the sixth embodiment. In order to simplify the explanation, the data channel in this embodiment is unidirectional from OXCA as the first upstream node 1 to OXCB as the downstream node, and from OXCC as the second upstream node 2 to OXCB as the downstream node. However, there is no limitation on the application of this embodiment even for a bidirectional data channel.

 In the network configuration shown in FIG. 31, three data channels and a bidirectional channel for controlling the data channel are connected between the OXCA and OXCB nodes. Further, three data channels and a bidirectional control channel for controlling the data channels are connected between the OXCC and OXCB nodes.

 Also, it is assumed that each data channel is assigned a unique interface ID within the node.

  In the sixth embodiment, when switching the data channel that terminates at a certain time in the upstream node, the data channel that detected the light signal is terminated within a certain time after the optical signal is detected in the downstream node. A function for performing switching control is provided in the LMP control unit 13. Thereby, topology detection is performed in a shorter time.

  Similar to the previous embodiment, three data channels Dch1 to Dch3 whose topology is not detected are provided between the upstream node and the downstream node, and the topology detection processing of these three data channels will be described.

 FIG. 32 is a sequence diagram illustrating an outline of the flow of the topology detection process according to the sixth embodiment. In the description of the sixth embodiment, each part of the OXC node uses the configuration of the second embodiment shown in FIG. 18, but the node configuration of the fourth embodiment of FIG. 25 can also be used. .

 The state of FIG. 32A is where the downstream node terminates the data channel with interface ID = 1 and waits for the reception of the TEST message from the upstream node 1. In this state, the downstream node receives the TEST message from the upstream node interface ID = 1 on the data channel of the downstream node interface ID = 2, and detects the optical signal by the optical reception IF unit 17 of the downstream node.

 When detected by the optical reception IF unit 17, the LMP control unit 13 searches the topology DB 20 to determine whether or not the data channel from which the optical signal is detected has already been detected. If it is determined that the topology of the data channel has not yet been detected, the LMP control unit 13 checks whether the data channel being terminated is in a waiting state for a predetermined time for receiving the TEST message. If it is determined that it is not in the waiting state, it requests the optical reception IF unit 17 to terminate the interface ID = 2, and starts a one-channel monitoring timer.

 The optical reception IF unit 17 switches the selector so that the optical signal flows into the O / E conversion unit 15 in order to terminate the data channel with the interface ID = 2. The relationship between the termination data channel in the upstream node 1 and the termination data channel in the downstream node in this state is as shown in FIG.

 In the state shown in FIG. 32B, since the data channel terminated at the upstream node 1 and the data channel terminated at the downstream node are the same, the downstream node receives the TEST message. Since the operation until the downstream node receives the TEST message and transmits the TestStatusSuccess message to the upstream node 1 is the same as that of the first embodiment, the description is omitted.

 The TestStatusSuccess message transmitted from the downstream node in this way reaches the upstream node 1. Since the upstream node 1 receives the TestStatusSuccess message on the control channel and determines the data channel for detecting the next topology, the operation is the same as in the fifth embodiment, and the description is omitted.

 As a result, when an optical signal is detected in a data channel different from the terminated data channel in the downstream node, even if one electrical termination function is used by switching the terminated data channel to the data channel. Topology detection can be performed in a short time.

 On the other hand, in the state shown in FIG. 32 (B), when the TEST message starts to be transmitted from the upstream node 2 while waiting for 100 msec to receive the TEST message from the upstream node 1, the downstream node receives the interface ID = 4 optical signals are detected. Similarly to the above, the LMP control unit 13 determines whether or not the topology of the data channel of the detected optical signal has already been detected. If it is determined that the topology of the data channel has not yet been detected, the LMP control unit 13 confirms whether the data channel being terminated is in a waiting state for a predetermined time for receiving the TEST message.

 At this time, the data channel of interface ID = 2 that terminates in the downstream node is in a wait state for the TEST message from the upstream node 1, so that the interface ID = 4 notified to the optical reception IF unit 17. No switch request is made to terminate the data channel.

 When the topology detection on the data channel with the interface ID = 2 is completed in the downstream node, the optical signal of the TEST message from the upstream node 2 is detected with the interface ID = 4. The operation until the optical reception IF unit 17 detects the optical signal and switches the terminal data channel to the data channel of the interface ID = 4 is the same as that already described.

 When the switching to the data channel of interface ID = 4 is completed, the device waits for a certain period of time to receive the TEST message from the upstream node 2. When the TEST message is not received while waiting for the TEST message reception, it waits until an optical signal is detected on another data channel.

 The state shown in FIG. 32C is that, in the upstream node 2, the 1-channel monitoring timer for monitoring the reception of the TestStatusSuccess message has timed out due to the data channel with the interface ID = 1. The operation of timer monitoring at the upstream node is the same as that of the fifth embodiment.

 On the other hand, when the waiting state on the data channel of interface ID = 4 of the downstream node is released, the optical signal is detected on the data channel of interface ID = 5. The operation until the optical reception IF unit 17 detects the optical signal and switches the data channel terminating to the data channel with the interface ID = 5 is the same as that already described.

 As shown in FIG. 32D, the upstream node 1 transmits a TEST message from the interface ID = 2, and the upstream node 2 transmits a TEST message from the interface ID = 2. At this time, since the data channel terminated at the upstream node 2 and the data channel terminated at the downstream node are the same, the TEST message is received. The operation until the downstream node receives the TEST message on the terminating data channel and transmits the TestStatusSuccess message is the same as that already described.

 The TestStatusSuccess message transmitted from the downstream node in this way reaches the upstream node 2. As a result, after switching the data channel to be terminated, it waits for the reception of the TEST message for a certain period of time. Even if an optical signal is detected by another data channel during this period, the switching is not performed, and the TEST message is received within a certain period of time. If the optical signal is detected on another data channel after the TEST message reception wait state is canceled without switching, the switching of the data channel to be terminated is prevented by switching, and one electrical termination function is used. Even in such a case, the topology can be detected in a short time.

 As described above, when an optical signal is detected by a data channel different from the data channel terminating at the downstream node while the data channel terminating at a certain time is switched in the upstream node, It is possible to detect the topology in a short time by switching to terminate the data channel, or waiting for a predetermined time after receiving the TEST message after the data channel to be terminated is switched, and preventing switching flapping.

 Next, the detailed operation of the sixth embodiment will be described with reference to the state transition diagrams of FIGS. 33.A to 33.E in the network configuration of FIG. 31 and the sequence operation diagram of the nodes of FIG.

 In the sixth embodiment, the state described in the fifth embodiment, that is, as shown in FIG. 33A, the upstream node 1 periodically sends out a TEST message, and terminates at the downstream node. In a situation where different data channels are used, it is possible to realize topology detection in a shorter time than in the fifth embodiment.

 In the description, each part uses the node configuration of FIG. 18, but this embodiment can be similarly realized in the node configuration of FIG.

 First, the state of FIG. 33A is where the downstream node OXCB terminates the data channel with interface ID = 1 and waits for the reception of the TEST message. The operation of messages other than the TEST message (eg, BeginVerify message) has already been described in the first embodiment, and the operation is exactly the same.

 In this state, when the data channel with the interface ID = 3 of OXCB receives the TEST message transmitted from OXCA which is the upstream node, the optical reception IF unit 17 in the present invention detects the optical signal (FIG. 34: S100). .

 The optical reception IF unit 17 notifies the LMP control unit 13 that the optical signal has been received with the interface ID = 3 (S101). Therefore, the LMP control unit 13 indexes the data channel management table of the topology DB 20, extracts the presence / absence of topology detection, and determines whether the topology has been detected (S102).

 In this case, since the topology detection has not been performed yet, the LMP control unit 13 confirms whether or not it is waiting for 100 msec for receiving the TEST message (S103). Since OXCB is an initial state in which the data channel of interface ID = 1, which is the youngest, is terminated and is not in a waiting state of 100 msec, the data of interface ID = 3 notified to the optical reception IF unit 17 is set. A channel termination request is made (S104). The optical reception IF unit 17 switches the selector so that the optical signal with the interface ID = 3 flows into the O / E conversion unit 15 in order to terminate the notified data channel with the interface ID = 3 (S105).

 In the downstream node OXCB, after switching the data channel to be terminated to the data channel with the interface ID = 3, in this embodiment, the data channel waits for 100 msec in order to receive the TEST message from OXCA (S106). ). As described in the previous embodiment, this 100 msec waiting state is necessary for the OXCB to receive the next TEST message because the TEST message from the upstream node OXCA is transmitted at a period of VerifyInterval (100 msec). It is a long waiting time.

 Here, as shown in FIG. 33B, when the OXCB optical reception IF unit 17 receives a TEST message from OXCA while the data channel of interface ID = 3 is waiting for 100 msec (S107: Yes), LMP control is performed. The unit 13 edits the TestStatusSuccess message (S108), and requests the control channel IF unit 12 to transmit the TestStatusSuccess message. The control channel IF unit 12 transmits a message using the notified control channel (S109).

 In this way, the TestStatusSuccess message transmitted from OXCB reaches OXCA. Here, in the fifth embodiment, the data channel that terminates when the upstream node holds a timer and terminates with a timeout is switched, so that the data channel that terminates the OXCB receives the first TEST message. 900 msec ((VerifyDeadInterval [100 msec × 3 times] × OXCA topology undetected data channel number [3])). On the other hand, in this embodiment, the data channel to be terminated is switched when the optical signal of the data channel is detected, and the TEST message is received within 100 msec (VerifyInterval) after the switching is completed until the next TEST message is transmitted. As a result, the topology detection time can be shortened.

 Next, as shown in FIG. 33C, when the TEST message is transmitted from the data channel of the second upstream node OXCC interface ID = 1 to the downstream node OXCB, the interface ID of OXCB = 4 Receive a TEST message on the data channel. The operation until the optical reception IF unit 17 of the OXCB detects an optical signal and switches to terminate the data channel with the interface ID = 4 is the same as that described above. When the switching of the OXCB termination data channel is completed in this way, the terminated data channel with the interface ID = 4 enters a waiting state of 100 msec for receiving the TEST message from the OXCC.

 In this state, as shown in FIG. 33D, when the data channel with the interface ID = 2 of the downstream node OXCB receives the TEST message from the data channel with the interface ID = 2 of the upstream node OXCA, OXCB The optical reception IF unit 17 detects an optical signal. Next, the LMP control unit 13 confirms whether the terminating data channel is waiting for 100 msec (S103). In this case, since the data channel with interface ID = 4 is waiting for 100 msec, a request for switching the data channel to be terminated to the optical reception IF unit 17 is not performed. (S110).

 Here, when the data channel with the interface ID = 4 of the OXCB completes the 100 msec wait state without receiving the TEST message, the OXCB detects the optical signal on the other data channel with the data channel with the interface ID terminated. Wait until

 In this state, as shown in FIG. 33.E, when the TEST message is transmitted from the upstream node OXCC interface ID = 2 to the downstream node OXCB, the data channel of the OXCB interface ID = 5 is transmitted. An optical signal is detected. Similarly, the LMP control unit 13 confirms whether the data channel with the interface ID = 4 being terminated is in a 100 msec waiting state. In this case, since the waiting state is not 100 msec, the optical receiving IF unit 17 is requested to terminate the data channel in which the optical signal is detected.

 The optical reception IF unit 17 switches the selector so that the optical signal with the interface ID = 5 flows into the O / E conversion unit 15 in order to terminate the notified data channel with the interface ID = 5. The operations from the completion of switching to the completion of topology detection are the same as those described above.

 Thus, the topology detection process between OXCA, OXCB, and OXCC is completed by performing the topology detection process for all of the OXCB interface IDs = 1 to 6 shown in FIG. 33A.

 As described above, the topology detection can be performed in a shorter time than in the fifth embodiment by switching the termination channel to the data channel in which the optical signal is detected in the downstream node.

(Additional remark 1) The 1st optical transmission apparatus which transmits the data channel signal of the light respectively transmitted by several data channels from the output port corresponding to each data channel, The data channel signal which this 1st optical transmission apparatus transmitted And an adjacent second optical transmission device that receives the data from an input port corresponding to each data channel,
The first optical transmission device includes:
A generation unit that generates a topology detection message including identification information of the output port and outputs it by an optical signal;
A transmission unit that selects one of the plurality of data channels as a data channel that terminates, and transmits the topology detection message output from the generation unit through the selected data channel;
A first control unit for controlling selection of a data channel of the transmission unit,
The second optical transmission device is:
A termination unit for converting an input optical signal into an electrical signal and terminating it;
A selection unit that selects one of the plurality of data channels and inputs a signal of the selected data channel to the termination unit;
A second storage unit that stores a correspondence relationship between the identification information of the output port and the identification information of the input port;
The selection unit controls the selection of the data channel, and when the termination unit receives the topology detection message from the selection unit, the identification information included in the received topology detection message, and the selection unit The data channel selected by the selection unit is stored in the second storage unit in association with the identification information of the input port of the data channel selected by the data channel selected by the selection unit when the termination unit does not receive the topology detection message. A second control unit for changing to another data channel;
An optical transmission system equipped with.

(Appendix 2) In Appendix 1,
The second optical transmission device further includes a reply unit that returns identification information of the output port and identification information of the input port to the first optical transmission device,
The first optical transmission device further includes a first storage unit that stores the output port identification information and the input port identification information returned from the second optical transmission device in association with each other.
Optical transmission system.

(Appendix 3) In Appendix 2,
The reply unit of the second optical transmission device sends back the identification information of the output port and the identification information of the input port by a control channel provided separately from the plurality of data channels;
Optical transmission system.

(Appendix 4) In any one of Appendices 1 to 3,
The first control unit of the first optical transmission device causes the transmission unit to select a data channel corresponding to an output port whose connection relationship with the input port of the second optical transmission device is unknown;
Optical transmission system.

(Appendix 5) In any one of Appendices 1 to 4,
The second control unit of the second optical transmission device causes the selection unit to select a data channel corresponding to an input port whose connection relationship with the output port of the first optical transmission device is unknown;
Optical transmission system.

(Appendix 6) In any one of Appendices 1 to 5,
The second optical transmission device is:
A light detection unit provided corresponding to each of the plurality of data channels, detecting light on the corresponding data channel and outputting a detection signal;
The detection signal from the light detection unit is input, the data channel corresponding to the detection unit that has output the detection signal is not selected by the selection unit, and the input port is the first optical transmission device A third storage unit that stores identification information of the input port in the case of a data channel whose connection relationship with the output port is not known;
An optical transmission system further comprising:

(Appendix 7) In Appendix 6,
The second control unit of the second optical transmission device stores the data channel selected by the selection unit in the third storage unit first when the termination unit does not receive the topology detection message. Change to the data channel corresponding to the identified information,
Optical transmission system.

(Appendix 8) In any one of Appendices 1 to 7,
The first optical transmission device further includes a light emitting unit provided corresponding to each of the plurality of data channels, and transmitting an optical signal to the corresponding data channel,
The first control unit of the first optical transmission device does not know a correspondence relationship with the input port of the second optical transmission device among data channels other than the data channel selected by the transmission unit. Send an optical signal to the light emitting part of the data channel corresponding to the output port,
Optical transmission system.

(Appendix 9) In any one of Appendices 1 to 8,
The second control unit of the second optical transmission device changes the data channel selected by the selection unit to another data channel when the termination unit does not receive the topology detection message for a predetermined time. change,
Optical transmission system.

(Supplementary Note 10) In any one of Supplementary Notes 1 to 9,
The selection unit of the second optical transmission device is disposed in front of an optical switch unit that switches a plurality of data channel signals in an optical state, and is provided corresponding to each of the plurality of data channels. A selector and an optical multiplexer;
Each of the optical selectors outputs an input data channel signal to the optical multiplexer or the optical switch unit based on the control of the second control unit,
The optical multiplexer selects one of the data channel signals from the optical selector based on the control of the second control unit and provides the selected signal to the termination unit;
Optical transmission system.

(Appendix 11) In any one of Appendices 1 to 9,
The selection unit of the second optical transmission device also serves as an optical switch unit that switches a plurality of data channel signals in an optical state.
Optical transmission system.

(Supplementary Note 12) An output port of the first optical transmission apparatus, which is executed between the adjacent first optical transmission apparatus and the second optical transmission apparatus that transmit and receive optical data channel signals respectively transmitted by a plurality of data channels. And a topology detection method for detecting a connection relationship with an input port of the second optical transmission device,
The first optical transmission device includes:
Selecting one of the plurality of data channels, and transmitting a topology detection message including identification information of an output port of the selected data channel through the selected data channel;
The second optical transmission device is:
Selecting and terminating one of the plurality of data channels;
When the topology detection message is received for the selected data channel, the identification information of the output port included in the received topology detection message is associated with the identification information of the input port of the selected data channel. Remember,
If the selected data channel does not receive the topology detection message, select another data channel and terminate;
Topology detection method.

(Supplementary note 13) An optical transmission device that receives optical data channel signals respectively transmitted through a plurality of data channels, and switches and transmits the received plurality of data channel signals in an optical state by an optical switch unit. ,
A termination unit for converting an input optical signal into an electrical signal and terminating it;
A selection unit that selects one of the plurality of data channels and provides a data channel signal of the selected data channel to the termination unit;
A control unit that controls selection of a data channel of the selection unit, and when the termination unit does not receive a signal from the selection unit, a control unit that changes the data channel selected by the selection unit to another data channel;
An optical transmission device comprising:

(Appendix 14) In Appendix 13,
The selection unit is arranged in front of the optical switch unit, and includes an optical selector provided corresponding to each of the plurality of data channels, and an optical multiplexer.
Each of the optical selectors outputs an input data channel signal to the optical multiplexer or the optical switch unit based on the control of the control unit,
The optical multiplexer selects one of the data channel signals from the optical selector based on the control of the control unit and provides the selected signal to the termination unit;
Optical transmission device.

(Supplementary Note 15) An optical transmission apparatus that receives optical data channel signals respectively transmitted through a plurality of data channels, and switches and transmits the received plurality of data channel signals in an optical state by an optical switch unit. ,
A termination unit for converting an input optical signal into an electrical signal and terminating it;
The switching of the switch unit is controlled to select one of the plurality of data channels, the data channel signal of the selected data channel is given to the termination unit, and the data channel selected by the optical switch unit A control unit for changing to a data channel of
An optical transmission device comprising:

(Supplementary Note 16) An optical transmission device that receives optical data channel signals respectively transmitted through a plurality of data channels, and switches and transmits the received plurality of data channel signals in an optical state by an optical switch unit. ,
A generation unit that generates a topology detection message for detecting a data channel connection relationship with an optical transmission device adjacent to the downstream side and outputs the topology detection message as an optical signal;
A transmission unit that selects one of the plurality of data channels, and transmits the topology detection message output from the generation unit to the downstream optical transmission device by the selected data channel;
An optical transmission device comprising:

(Appendix 17) In Appendix 16,
The transmission unit is an optical transmission device provided at a subsequent stage of the optical switch unit.

(Supplementary Note 18) An optical transmission apparatus that receives optical data channel signals respectively transmitted through a plurality of data channels, and switches and transmits the received plurality of data channel signals in an optical state by an optical switch unit. ,
A generation unit that generates a topology detection message for detecting a data channel connection relationship with an optical transmission device adjacent to the downstream side, and outputs the topology detection message to the optical switch unit by an optical signal;
An optical transmission device that controls switching of the optical switch unit to select one of the plurality of data channels, and uses the selected data channel to transmit the topology detection message output from the generation unit to the downstream side A control unit that controls to transmit to
An optical transmission device comprising:

(Supplementary Note 19) A first optical transmission apparatus that transmits optical data channel signals respectively transmitted through a plurality of data channels from an output port corresponding to each data channel, and a data channel signal transmitted by the first optical transmission apparatus And an adjacent second optical transmission device that receives from the input port corresponding to each data channel, and further includes a control channel between the first optical transmission device and the second optical transmission device. There,
The first optical transmission device includes:
A generation unit that generates a topology detection message including identification information of the output port and outputs it by an optical signal;
A transmission unit that selects one of the plurality of data channels as a data channel that terminates, and transmits the topology detection message output from the generation unit through the selected data channel;
A first controller that controls selection of a data channel of the transmitter;
A monitoring timer for detecting a response signal from the second optical transmission device to the topology detection message on the control channel;
The second optical transmission device is:
A termination unit for converting an input optical signal into an electrical signal and terminating it;
A selection unit that selects one of the plurality of data channels and inputs a signal of the selected data channel to the termination unit;
A second storage unit that stores a correspondence relationship between the identification information of the output port and the identification information of the input port;
The selection unit controls the selection of the data channel, and when the termination unit receives the topology detection message from the selection unit, the identification information included in the received topology detection message, and the selection unit A second control unit that stores the identification information of the input port of the data channel selected by the second storage unit in association with each other,
Furthermore, when the first optical transmission apparatus does not receive the response signal within one channel monitoring timer period by the monitoring timer, the first control unit selects a new data channel to be terminated, and The optical transmission system is characterized in that the selection unit selects one of the new data channels when receiving the topology detection message.

(Supplementary note 20) In claim 19,
The new data channel that is selected and terminated when the topology detection message is received by the selection unit of the second optical transmission device is transmitted from the first optical transmission device by the data channel selected by the selection unit. An optical transmission system which is a data channel that detects an optical signal while waiting for a topology detection message.

(Supplementary Note 21) An output port of the first optical transmission apparatus, which is executed between the adjacent first optical transmission apparatus and the second optical transmission apparatus that transmit and receive optical data channel signals respectively transmitted by a plurality of data channels. And a topology detection method for detecting a connection relationship with an input port of the second optical transmission device,
The first optical transmission device includes:
Selecting one of the plurality of data channels, and transmitting a topology detection message including identification information of an output port of the selected data channel through the selected data channel;
A response signal from the second optical transmission device to the topology detection message is monitored by a timer on a control channel between the first optical transmission device and the second optical transmission device;
The second optical transmission device is:
Selecting and terminating one of the plurality of data channels;
When the topology detection message is received for the selected data channel, the identification information of the output port included in the received topology detection message is associated with the identification information of the input port of the selected data channel. Remember,
Further, the first optical transmission apparatus selects a new data channel to be terminated when the response signal on the control channel for the topology detection message is not received for a predetermined period by the timer monitoring. .

  There is provided an optical transmission system that can reduce the cost of an optical transmission apparatus by reducing the hardware required for electrical conversion and termination processing because only one termination is required to terminate the topology detection message.

It is a sequence diagram which shows the procedure of the topology detection process by a Link Verification function. It is a sequence diagram which shows the procedure of the topology detection process by a Link Verification function. It is a block diagram which shows a part of optical transmission system by the 1st Example of this invention. It is a block diagram which shows the structure of the OXC node by the 1st Example of this invention. It is a block diagram which shows the detailed structure of an optical reception IF part. It is a block diagram which shows the detailed structure of an optical transmission IF part. An example of a data channel management table is shown. An example of a control channel management table is shown. Indicates the data structure of the BeginVerify message. Indicates the data structure of the BeginVerifyAck message. Shows the data structure of the Test message. Shows the data structure of the TestStatusSuccess message. It is a sequence diagram which shows the outline of the flow of the topology detection process by 1st Example of this invention. It is a sequence diagram which shows the topology detection process flow of the upstream node by 1st Example of this invention. It is a sequence diagram which shows the topology detection process flow of the upstream node by 1st Example of this invention. It is a sequence diagram which shows the flow of the topology detection process of the downstream node by 1st Example of this invention. It is a sequence diagram which shows the flow of the topology detection process of the downstream node by 1st Example of this invention. It is a block diagram which shows the structure of the OXC node by the 2nd Example of this invention. The data structure of the topology detection candidate channel queue of the topology detection order control unit is shown. It is a sequence diagram which shows the outline of the flow of the topology detection process by the 2nd Example of this invention. It is a sequence diagram which shows the flow of the topology detection process of the upstream node by the 2nd Example of this invention. It is a sequence diagram which shows the flow of the topology detection process of the downstream node by the 2nd Example of this invention. It is a sequence diagram which shows the flow of the topology detection process of the downstream node by the 2nd Example of this invention. It is a block diagram which shows the structure of the OXC node by the 3rd Example of this invention. It is a block diagram which shows the structure of the OXC node by the 4th Example of this invention. It is a sequence diagram which shows the outline of the flow of the topology detection process by the 5th Example of this invention. It is a sequence diagram which shows the flow of the topology detection process of the upstream node by the 5th Example of this invention. It is a sequence diagram which shows the flow of the topology detection process of the upstream node by the 5th Example of this invention. It is a sequence diagram which shows the flow of the topology detection process of the upstream node by the 5th Example of this invention. It is a sequence diagram which shows the flow of the topology detection process of the downstream node by the 5th Example of this invention. It is a figure which shows the network structure in application of a 6th Example. It is a sequence diagram which shows the outline of the flow of the topology detection process by the 5th Example of this invention. It is a figure which shows the state transition of the network structure in application of a 6th Example. It is a figure which shows the state transition of the network structure in application of a 6th Example. It is a figure which shows the state transition of the network structure in application of a 6th Example. It is a figure which shows the state transition of the network structure in application of a 6th Example. It is a figure which shows the state transition of the network structure in application of a 6th Example. It is a sequence diagram which shows the flow of the topology detection process of the downstream node by the 6th Example of this invention.

Explanation of symbols

A, B, C OXC node 12 Control channel IF unit 13 LMP control unit 14 Control signal termination unit 15 O / E conversion unit 16, 161 Optical switch unit 17, 170, 172 Optical reception IF unit 18, 180, 181 Optical transmission IF Unit 19 Topology detection order control unit 20 Topology database

Claims (6)

A first optical transmission device that transmits an optical data channel signal respectively transmitted through a plurality of data channels from an output port corresponding to each data channel, and a data channel signal transmitted by the first optical transmission device is transmitted to each data An optical transmission system having an adjacent second optical transmission device receiving from an input port corresponding to a channel,
The first optical transmission device includes:
A generation unit that generates a topology detection message including identification information of the output port and outputs it by an optical signal;
A transmission unit that selects one of the plurality of data channels and transmits the topology detection message output from the generation unit through the selected data channel;
A first controller that controls selection of a data channel of the transmitter;
With
The second optical transmission device is:
A termination unit common to the plurality of data channels for terminating the plurality of input data channel optical signals by converting them into electrical signals;
A selection unit that selects one of the plurality of data channels and inputs a signal of the selected data channel to the termination unit;
The identification information and the identification information store a correspondence relationship SL and憶部of said input ports of said output ports,
The selection unit controls the selection of the data channel, and when the termination unit receives the topology detection message from the selection unit, the identification information included in the received topology detection message, and the selection unit in association with the identification information of the input ports of the selected data channel previously stored Kiki憶部result, when the end portion does not receive the topology detection message, the data channel selected by the selection unit A second control unit for changing to another data channel;
An optical transmission system equipped with. In claim 1,
The second optical transmission device further includes a reply unit that returns identification information of the output port and identification information of the input port to the first optical transmission device,
Wherein the first optical transmission apparatus, the second said output port identification information and said input port further comprising in that the optical transmission system in association with that Symbol憶部to store identification information returned from the optical transmission device. In claim 1 or 2,
The optical transmission system, wherein the first control unit of the first optical transmission device causes the transmission unit to select a data channel corresponding to an output port whose connection relationship with an input port of the second optical transmission device is unknown. In any one of Claim 1 to 3,
The second transmission unit of the second optical transmission device causes the selection unit to select a data channel corresponding to an input port whose connection relationship with the output port of the first optical transmission device is unknown. In any one of Claims 1-4,
The second optical transmission device is:
A light detection unit provided corresponding to each of the plurality of data channels, detecting light on the corresponding data channel and outputting a detection signal;
The detection signal from the light detection unit is input, the data channel corresponding to the detection unit that has output the detection signal is not selected by the selection unit, and the input port is the first optical transmission device If it is found to not data channel connection relationship between the output ports, and that SL憶部to store identification information of the input port,
An optical transmission system further comprising: Executed between adjacent first and second optical transmission devices for transmitting and receiving optical data channel signals respectively transmitted by a plurality of data channels, and an output port of the first optical transmission device; A topology detection method for detecting a connection relationship with an input port of a two-optical transmission apparatus,
The first optical transmission device includes:
Selecting one of the plurality of data channels, and transmitting a topology detection message including identification information of an output port of the selected data channel through the selected data channel;
The second optical transmission device is:
Selecting one of the plurality of data channels and terminating at a common termination to the plurality of data channels ;
When the topology detection message is received for the selected data channel, the identification information of the output port included in the received topology detection message is associated with the identification information of the input port of the selected data channel. Remember,
If the selected data channel does not receive the topology detection message, select another data channel and terminate;
Topology detection method.

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