JP2015204467A - Communication device, optical transmission system, and optical transmission device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a communication device that realizes a reliable optical transmission system.SOLUTION: The present invention is a communication device constituent of a multilayered optical transmission system. The communication device comprises: interlayer communication means (network interface 127, 227) for communicating with another layer communication device, a communication device in a layer different from the layer of the communication device; information management means (L0 path control DB 126 and L1 path control DB 226) for managing information on whether it is possible or not to perform control frame transmission via the layer to which the other layer communication device belongs for each of other communication devices in the same layer as the communication device; and transfer destination determination means (L0 path control unit 121 and L1 path control unit 221) for determining a transfer destination when transferring a control frame transmitted to another destination communication device in the same layer as the communication device on the basis of the information managed by the information management means.

Description

  The present invention relates to a communication apparatus, an optical transmission system, and an optical transmission apparatus that constitute an optical transmission network to which wavelength division multiplexing is applied.

  In an optical transmission network to which wavelength division multiplexing is applied, it is desired to realize cost reduction and efficient accommodation of services. For this reason, an ODUXC (Optical Cross Connect (ROADM) device or an OXC (Optical Cross Connect) device that includes a wavelength multiplexing interface and performs wavelength path switching without converting an optical signal into an electrical signal. Multi-layering is being promoted by applying an optical transmission device that integrates layer or layer 2 switch devices such as ODU Cross Connect (MPU) devices and MPLS-TP (Multi Protocol Label Switching Transport Profile) switch devices. Also, in order to make the optical transmission network highly reliable, ROADM devices and OXC devices become multi-way, so that the network topology changes from a simple topology such as a single ring to a multi-ring / mesh, and a large number of redundant routes. It is possible to construct a highly reliable network that can take off. In addition, by applying WSS (Wavelength Select Switch) to these transmission devices, it is possible to set an optical path to an arbitrary wavelength in an arbitrary path without field work. It is sometimes possible to provide a restoration function for establishing and switching a new normal optical path.

  In the switching of the detour route by the restoration function, the network management device collects the failure status by the alarm notification, determines the switching order and the detour route according to the reliability request of the accommodation service, and instructs each device to set the path ( Non-patent document 1).

  The control frame (monitoring control frame) used for alarm notification, path switching instruction, and inter-device signaling communication for path switching control, etc., includes the out-of-band monitoring control system and the in-band monitoring control system. There are two ways. The out-band supervisory control method performs supervisory control of the optical transmission apparatus using a supervisory line other than the network to be monitored. The in-band supervisory control method is a method for supervising and controlling an optical transmission apparatus via a network to be monitored. When the optical transmission apparatus is located at a remote site and there is no out-band monitoring line, an in-band monitoring method is used (see Patent Document 1).

Japanese Patent No. 4673994

Horiuchi and 3 others "Network control and operation management of photonic network", IEICE Technical Report PN2012-11

  When the above-mentioned in-band monitoring and control method is applied, a transmission path failure also affects the in-band monitoring and control network. Therefore, alarm notification and path switching instruction used during restoration control, and inter-device signaling for path switching control There is a possibility that a monitoring control frame such as communication may be lost. For example, when routing protocols such as OSPF (Open Shortest Path First) and RIP (Routing Information Protocol) are used for path control of the in-band supervisory control network, each device collects route information by exchanging control packets with neighboring devices. Based on this information, the route of the monitoring control communication is switched. There is a possibility that the monitoring control frame may be lost because the routing is not normally performed until the path information has converged.

  The present invention has been made in view of the above, and is intended to improve the reliability of an in-band supervisory control network, ensure the reachability of a supervisory control frame necessary for device setting control, and ensure restoration in an optical transmission network. It is an object of the present invention to obtain a communication device that realizes a reduction in performance and failure recovery time.

  In order to solve the above-described problems and achieve the object, the present invention provides a communication device that constitutes a multi-layered optical transmission system, and another layer communication device that is a communication device of a layer different from itself. Information for managing information on whether or not control frame transmission via the layer to which the other layer communication device belongs is possible for each of the communication means between layers for communication and other communication devices in the same layer as itself Management means; and transfer destination determination means for determining a transfer destination when transferring a control frame transmitted to another communication device in the same layer as itself based on information managed by the information management means, It is characterized by providing.

  According to the present invention, for example, when a control frame is received in a state where a failure has occurred in the own layer, the control frame can be transferred to the destination via another layer, thereby realizing a highly reliable network. There is an effect that it is possible.

FIG. 1 is a diagram illustrating a configuration example of an optical transmission system to which a communication device according to the present invention is applied. FIG. 2 is a diagram illustrating a configuration example of the optical transmission apparatus. FIG. 3 is a diagram illustrating an example of route information (route table) held by the OXC apparatus. FIG. 4 is a diagram illustrating an example of route information (route table) held by the ODUXC apparatus. FIG. 5 is a diagram illustrating an example of route information (route table) held by the OXC apparatus. FIG. 6 is a diagram illustrating an example of route information (route table) held by the ODUXC apparatus. FIG. 7 is a flowchart illustrating an example of the transfer process of the monitoring control frame. FIG. 8 is a diagram illustrating a monitoring control frame transfer operation when a failure occurs.

  Embodiments of a communication apparatus according to the present invention will be described below in detail with reference to the drawings. Note that the present invention is not limited to the embodiments.

Embodiment 1 FIG.
FIG. 1 is a diagram illustrating a configuration example of an optical transmission system to which a communication device according to the present invention is applied. As shown in the figure, the optical transmission system includes a multilayered optical transmission network. In the example shown in FIG. 1, a lower layer L0 (Layer 0) network is configured by OXC apparatus 10 ₁ to 10 ₇ as a communication device belonging to layer 0. The L1 (layer 1) network, which is the upper layer of the L0 network, is configured by ODUXC devices 20 ₁ , 20 ₂ , 20 ₄ , 20 ₅ and 20 ₇ as communication devices belonging to layer 1. Also, the OXC device 10 ₁ and the ODUXC device 20 ₁ , the OXC device 10 ₂ and the ODUXC device 20 ₂ , the OXC device 10 ₄ and the ODUXC device 20 ₄ , the OXC device 10 ₅ and the ODUXC device 20 ₅ , the OXC device 10 ₇ and the ODUXC device 20. Reference numeral ₇ denotes an optical transmission apparatus that is an integrated apparatus that is arranged in the same station and interfaces with a wavelength path. In FIG. 1, N101 to N107 and N201 to N207 described in each OXC device and ODUXC device are device IDs of the respective devices.

The OXC apparatus 10 (10 ₁ , 10 ₂ ,...) Constructs an L0 network that links the wavelength-multiplexed fibers L11 to L19, and provides services to client apparatuses (not shown) through wavelength paths. Further, the ODUXC apparatus 20 (20 ₁ , 20 ₂ ,...) Constructs an L1 network that links the wavelength paths L21 to L26, and provides services to the client apparatus through an electrical path having a finer granularity than the wavelength path.

  Regarding the in-band monitoring and control method of each layer, the OXC device 10 and the ODUXC device 20 construct an in-band monitoring and control network in each layer, and operate, monitor, and operate the network management device 1 and each device in the same network. Send and receive information necessary for control.

  In the L0 network constructed by the OXC apparatus 10, for example, ITU-T Recommendation G. An L0 in-band supervisory control network is constructed using OSC (Optical Supervisory Channel), which is supervisory control light dedicated to supervisory control shown in 709. In the example of FIG. 1, an in-band monitoring and control network that links L11 to L19 is constructed.

  In the L1 network constructed by the ODUXC apparatus 20, for example, ITU-T Recommendation G. Using the GCC (General Communication Channel) area of the main signal overhead shown in 709, an L1 in-band supervisory control network is constructed. In the example of FIG. 1, an L1 in-band monitoring and control network with L21 to L26 as links is constructed.

  The L0 network and the L1 network are connected to the network management apparatus 1 via a DCN (Data Communication Network) 2. That is, the OXC device 10 and the ODUXC device 20 of each layer are connected to the network management device 1 via the DCN 2.

The OXC device 101 connected to the DCN ₂ is a gateway device in the L0 network, and performs protocol conversion between the DCN 2 and the L0 in-band monitoring control network. The ODUXC device 201 connected to the DCN ₂ is a gateway device in the L1 network, and performs protocol conversion between the DCN 2 and the L1 in-band monitoring control network.

  The OXC device 10 in the L0 layer and the ODUXC device 20 in the L1 layer perform monitoring control communication with the network management device 1 and devices in the same network via each in-band monitoring control network. A routing protocol such as OSPF or RIP or a vendor-specific protocol is applied to the path control of the in-band supervisory control network of each layer.

FIG. 2 is a diagram illustrating a configuration example of the optical transmission apparatus according to the first embodiment. As an example, a configuration example of an optical transmission device including the OXC device 10 ₄ and the ODUXC device 20 ₄ illustrated in FIG. 1 is illustrated. The other optical transmission device (optical transmission device comprising a OXC device 10 ₁ and ODUXC device 20 _1, the optical transmission device comprising a OXC device 10 ₂ and ODUXC device 20 _2, etc.) is the same structure of. FIG. 2 shows specific functional configurations of the OXC device 10 ₄ and the ODUXC device 20 ₄ .

As shown in FIG. 2, OXC device ₁₀₄ includes a device monitoring control unit 12, and a plurality of transponder 13-1 13-n, a MUX / DEMUX unit 14, an OXC section 15, a plurality of AMP section 16-1 to 16-n and a plurality of OSC units 17-1 to 17-n. Further, ODUXC device 20 _4, a device monitoring control unit 22, and 23-n from a plurality of client signal accommodating portion 23-1, the XC 24, and a plurality of line signal receiving unit 25 - 1 25-n, It is comprised by.

It described respective portions of the OXC apparatus 10 _4. The device monitoring control unit 12 includes a CPU (Central Processing Unit), and this CPU realizes an L0 path control unit 121, a switching management unit 122, a failure management unit 123, an L0 path management unit 124, and a configuration management unit 125. Yes.

The L0 path control unit 121 transmits / receives a control frame used in the routing protocol applied to the L0 in-band monitoring control network to / from the adjacent OXC device 10 via the OSC light terminated at the OSC units 17-1 to 17-n. , Performs route management of the L0 in-band monitoring control network. The switching management unit 122 manages the switching state of the MUX / DEMUX unit 14 and the OXC unit 15. The failure management unit 123 monitors alarm information and transmission path performance information detected by the transponder unit 13. The L0 path management unit 124 includes wavelength protocol attribute information, wavelength path route information, signaling protocols such as GMPLS (Generalized Multi-Protocol Label Switching) protocol and APS (Automatic Protection Switching) protocol used for wavelength path switching control. Perform state management. The configuration management unit 125 manages the configurations of the transponder unit 13, the MUX / DEMUX unit 14, the OXC unit 15, the AMP units 16-1 to 16-n, and the OSC units 17-1 to 17-n included in the own device. . In addition, the device monitoring control unit 12 is connected to the network management device 1 via the L0 route control database (DB) 126 holding the route information of the monitoring control frame to each OXC device 10 in the L0 network and the DCN 2. includes being disposed in the same station in the building, a network IF (NW IF) 127 for exchanging device monitoring control unit 22 and the route information ODUXC device 20 ₄ that interfaces with wavelength path, a.

  The transponder units 13-1 to 13-n are connected to client devices such as an IP router and an L2 switch (not shown), and are connected to 100 GbE (100 Gigabit Ethernet (registered trademark)) or 10 GbE (10 Gigabit Ethernet (registered trademark)). The client signals such as Ethernet (registered trademark) signals and SONET / SDH (Synchronous Optical Network / Syncronous Digital Hierarchy) signals are accommodated. Specifically, ITU-T G.I. The wavelength path is terminated by mapping to an OTU (Optical Transport Unit) frame defined in 709, converted into a wavelength signal by electrical / optical conversion, and converted to a wavelength that is output to a transmission line fiber. In addition, the wavelength signal input from the transmission line fiber is subjected to conversion opposite to the conversion performed on the client signal. The transponders 13-1 to 13-n include an error correction circuit for guaranteeing quality degradation of the transmission signal, perform error correction code processing, and perform LOS (Loss of Signal) and LOF (Loss of Frame). ), Detection of cause alarms that are the main causes of failures such as LOM (Loss of Multiframe), and ITU-T G. Transmission quality using BIP-8 (Bit Interleaved Parity) by terminating various OTN overheads such as OTU overhead, ODU (Optical Data Unit) overhead, and TCM (Tandem Connection Monitoring) overhead It performs monitoring, fiber connectivity confirmation using TTI (Trail Trace Identifier), and insertion and detection of various maintenance signals such as AIS (Alarm Indication Signal) signals.

The MUX / DEMUX unit 14 wavelength-multiplexes the wavelength signals received from the line signal accommodating unit 25 of the transponder unit 13 and the ODUXC device 20 ₄ (ODUXC device 20 that constitutes an optical transmission device together with the own device), and wavelength-multiplexed signals To the OXC unit 15. Further, a wavelength-multiplexed signal received from OXC 15 and wavelength separation, and transmits to the transponder unit 13 and ODUXC device 20 _fourth line signal receiving portion 25 as OCh (Optical Channel) signal.

  The OXC unit 15 drops an arbitrary OCh signal from the wavelength multiplexed signal received from the AMP units 16-1 to 16-n on an arbitrary route and transmits the dropped OCh signal to the MUX / DEMUX unit 14. Further, the OCh signal received from the MUX / DEMUX unit 14 is added to the wavelength division multiplexed signal of an arbitrary route and transmitted from the AMP units 16-1 to 16-n. Further, there is a case where the wavelength multiplexed signal received from the AMP units 16-1 to 16-n on an arbitrary route is transmitted and transmitted to the AMP units 16-1 to 16-n on other routes.

  The AMP units 16-1 to 16-n transmit and receive wavelength multiplexed signals to and from other OXC devices 10.

  The OSC units 17-1 to 17-n are used for alarm transfer information below the OCh layer, monitoring control frames from the network management device 1 such as SNMP (Simple Network Management Protocol) Trap and Get / Set, and monitoring control used in signaling. In addition to transferring frames and the like, the OSC light that is a monitoring control channel for transmitting and receiving a routing message that is terminated by the L0 path control unit 121 of the device monitoring control unit 12 is terminated. The OSC units 17-1 to 17-n are provided for each route, and transmit and receive the monitoring control frame between adjacent optical transmission nodes (OXC devices) to construct an L0 in-band monitoring control network.

We explained each unit of ODUXC device 20 _4. The device monitoring control unit 22 includes a CPU, and the CPU realizes an L1 path control unit 221, a switching management unit 222, a failure management unit 223, an L1 path management unit 224, and a configuration management unit 225.

  The L1 path control unit 221 is a control used in the routing protocol applied to the L1 in-band monitoring control network via the main signal overhead for monitoring control communication such as GCC that terminates in the line signal accommodating units 25-1 to 25-n. The frame is transmitted / received to / from the adjacent ODUXC apparatus 20, and the path management of the L1 in-band monitoring control network is performed.

  The switching management unit 222 manages the switching state of the XC unit 24.

  The failure management unit 223 monitors alarm information and transmission path performance information detected by the client signal accommodating units 23-1 to 23-n and the line signal accommodating units 25-1 to 25-n.

  The L1 path management unit 224 performs state management of signaling information such as LMP path attribute information and route information, and GMPLS protocol and APS protocol used for switching control of the L1 path.

  The configuration management unit 225 manages the configurations of the plurality of client signal accommodation units 23-1 to 23-n, the XC unit 24, and the plurality of line signal accommodation units 25-1 to 25-n included in the own device. .

The device monitoring control unit 22 is connected to the network management device 1 via the L1 route control database (DB) 226 holding the route information of the monitoring control frame to each ODUXC device 20 in the L1 network and the DCN 2. , are arranged in the same station in the building, and a network IF (NW IF) 227 for exchanging device monitoring control unit 12 and the route information of the OXC apparatus ₁₀₄ that interfaces with wavelength path.

  The client signal accommodating units 23-1 to 23-n are connected to client devices such as IP routers and L2 switches (not shown), and receive client signals such as Ethernet (registered trademark) signals such as 100 GbE, 10 GbE, and GbE. Accommodates and maps to the LO ODU frame to terminate the L1 path.

  The XC unit 24 transmits the L1 path (LO ODU frame) received from the client signal accommodating units 23-1 to 23-n to any line signal accommodating unit in the line signal accommodating units 25-1 to 25-n. .

  The line signal accommodating units 25-1 to 25-n map the input LO ODU frame to the HO ODU frame, terminate the wavelength path, convert it into a wavelength signal by electrical / optical conversion, and output it to the transmission line fiber. In addition, a process (inverse conversion) opposite to the process of converting the wavelength signal input from the transmission line fiber into the above-described wavelength signal is performed.

Next, the route information held in the L0 route control DB 126 and the route information held in the L1 route control DB 226 will be described with reference to FIGS. FIG. 3 is a diagram showing an example of route information (route table) held in the L0 route control DB 126 of the OXC device 10 ₁ (OXC device whose device ID is N101) shown in FIG. FIG. 4 is a diagram showing an example of route information held in the L0 route control DB 126 of the ODUXC device 20 ₁ (ODUXC device whose device ID is N201) shown in FIG. FIG. 5 is a diagram showing an example of route information (route table) held in the L0 route control DB 126 of the OXC device 10 ₄ (OXC device whose device ID is N104) shown in FIG. FIG. 6 is a diagram showing an example of route information held in the L0 route control DB 126 of the ODUXC device 20 ₄ (ODUXC device whose device ID is N204) shown in FIG.

For example, OXC _device 101 with ID N101 via the OSC light terminating the OSC section 17-1 at 17-n, and transmits and receives control frames of the route information such as advertisement of routing protocols, L0-band monitoring The ID of each OXC device in the control network ((a) destination L0 device ID shown in FIG. 3) and the ID of the next hop OXC device when transferring the control frame to the OXC device of that ID ((b) the next hop L0 device ID) and the number of hops ((c) number of hops) required to reach the OXC device of the destination L0 device ID are generated and held in the L0 route control database 126. Each OXC device 10 gives the ID of the connected ODUXC device 20 in addition to its own device ID when advertising routing information using the routing protocol when the ODUXC device 20 connected by the network IF 127 exists. Then advertise. For example, OXC apparatus 10 _1, because it is connected to the ODUXC device 20 _1, advertising to impart N201 is the ID of the ODUXC device 20 ₁ in the route information. Meanwhile, since the ODUXC apparatus connected by a network IF127 is the OXC apparatus ₁₀₃ does not exist, OXC device ₁₀₃ advertises the route information ID of ODUXC device is not assigned. Thereby, each OXC device 10 can learn the device ID of the ODUXC device 20 connected to the destination OXC device ((d) the L1 device ID connected to the destination L0 device). The L0 route control unit 121 of the OXC apparatus 10 performs advertisement such as route information.

Similarly, the ODUXC device 20 whose device ID is N201 transmits / receives a control frame such as routing information advertisement of the routing protocol via the overhead for monitoring control communication terminated at the line signal accommodating units 25-1 to 25-n. ID of each ODUXC device in the L1 in-band monitoring control network ((a) destination L1 device ID shown in FIG. 4) and ID of the next hop UXUXC device when the control frame is transferred to the ODUXC device of that ID ((B) Next hop L1 device ID) and the number of hops until reaching the ODUXC device of the destination L1 device ID ((c) hop number) are generated and held in the L1 route control database 226. Each ODUXC device 20 gives the ID of the connected OXC device 10 in addition to its own device ID when advertising route information using the routing protocol when the OXC device 10 connected by the network IF 227 exists. Then advertise. For example, ODUXC device 20 _1, because it is connected to the OXC _device 101 advertises to impart N101 is the ID of the OXC apparatus 10 ₁ in the route information. Thereby, each ODUXC device 20 can learn the ID of the OXC device 10 connected to the destination ODUXC device 20 ((d) the L0 device ID connected to the destination L1 device). The advertisement of route information and the like is performed by the L1 route control unit 221 of the ODUXC device 20.

OXC apparatus 10 _1, when learning of the column (d) from a column of the path table shown in FIG. 3 (a) is terminated, via a network IF127, to be that the information (destination L0 apparatus described in column (d) L1 apparatus ID attached), specifically, to notify the N202, N204, N205 and N207 to ODUXC device 20 _1. ODUXC device 20 ₁ which has received this notification refers to the L1 path control DB 226 (routing table shown in FIG. 4), L1 device ID notified shows the ODUXC device reachable via L0-band monitoring control network Therefore, the column (e) corresponding to the notified L1 device ID, that is, “(e) whether it is reachable via the L0 in-band monitoring control network” is set to “YES”. ODUXC device 20 _1, for example, the N202 is notified, the (e) the column of (a) searching the line (record) to the destination L1 device ID column "N202" is registered, the search record Set to “YES”. As a result, learning (updating) of the routing table held in the L1 routing control DB 226 is completed.

Similarly, ODUXC device 20 _1, the learning of the column (d) from the column (a) of the path table shown in FIG. 4 terminates, via a network IF227, information registered in the column (d) (Destination L1 L0 apparatus ID attached to the device), specifically, to notify the N102, N104, N105 and N107 the OXC apparatus 10 _1. OXC _device 101 which has received this notification refers to the L0 routing DB 126 (routing table shown in FIG. 3), L0 device ID notified shows the ODUXC device reachable via L1-band monitoring control network Therefore, the (e) column corresponding to the notified L0 device ID, that is, “(e) whether it is reachable via the L1 in-band monitoring control network” is set to “YES”. OXC _device 101 is, for example, the N102 is notified, the (e) the column of (a) searching the line (record) to the destination L0 apparatus ID column "N102" is registered, the search record Set to “YES”. As a result, the learning (updating) of the route table held in the L0 route control DB 126 is completed.

  In the L0 in-band monitoring control network, an ODUXC device 20 (first ODUXC device) is connected to an OXC device 10 that transmits (transfers) a monitoring control frame, and the ODUXC device 20 (the ODUXC device 20 ( If the second ODUXC device) is connected, and the path from the first ODUXC device to the second ODUXC device exists in L1 (layer 1), the other layer (L1 in-band monitoring and control network) The monitoring control frame can be reached via the route. Similarly, in the L1 in-band supervisory control network, the OXC apparatus 10 (first OXC apparatus) is connected to the transmission source ODUXC apparatus 20 of the supervisory control frame, and the OXC apparatus 10 (first OXC apparatus 20 is also connected to the destination ODUXC apparatus 20). 2 OXC devices) are connected, and when the route from the first OXC device to the second OXC device exists in L0 (layer 0), it passes through another layer (L0 in-band monitoring control network). The monitoring control frame can be reached at

  Next, the transfer operation of the monitoring control frame by the OXC apparatus 10 and the ODUXC apparatus 20 according to the present embodiment will be described. Since the transfer operation of the OXC device 10 and the transfer operation of the ODUXC device 20 when receiving the monitoring control frame are the same, they will be described together.

  FIG. 7 is a flowchart illustrating an example of transfer processing of each device (OXC device 10 and ODUXC device 20) that has received the monitoring control frame.

  When the OXC device 10 and the ODUXC device 20 receive the monitoring control frame, the OXC device 10 and the ODUXC device 20 first refer to the route table held in the database (L0 route control DB 126, L1 route control DB 226), and the destination device of the received monitoring control frame is It is confirmed whether or not it is reachable, that is, whether or not the destination device ID is registered in the column (a) (destination L0 device ID, destination L1 device ID) (step S11). If the destination device is reachable (step S11: Yes), it is confirmed whether there is a failure in the link with the next-hop device to be transferred (S12). If there is no failure (step S12: Yes), the monitoring control frame is transferred to the next-hop device (step S14). On the other hand, when the destination device is unreachable (step S11: No) and when there is a failure in the link with the next-hop device to be transferred (step S12: No), the (e) column ( Whether or not the destination device can be reached via another layer is checked by referring to whether or not the destination device can be reached via the L1 / L0 in-band monitoring and control network (step S13). When reachable (step S13: Yes), the monitoring control frame is transferred to another layer (OXC device 10 / ODUXC device 20) via the inter-device interface (network IF 127/227) (step S15). On the other hand, when it is not reachable (step S13: No), the monitoring control frame is discarded (step S16).

  Each determination process shown in FIG. 7 is performed by the device monitoring control unit 12 (particularly, the L0 route control unit 121) in the OXC device 10, and the device monitoring control unit 22 (particularly, the L1 route control unit 221) in the ODUXC device 20. ) Do.

The effect when this embodiment is applied will be described with reference to FIG. 8, in the network configuration shown in FIG. 1 shows the operation of the case of transmitting the monitoring control frame from the network management apparatus 1 to ODUXC 20 ₇ addressed in a failed state in the link L26. ODUXC 20 ₄ executes the processing in accordance with the monitoring control frame transfer flow shown in FIG. 7, since the link to ODUXC device 20 ₇ destination has failed to reach to the destination via another layer To see if it is possible. Then, since it is possible to reach the destination, the OXC apparatus ₁₀₄ connected via the network IF227 transfers monitoring control frame, the monitor control until ODUXC 20 ₇ destinations via L0-band monitoring control network The frame arrives. In the layer 1 where the failure occurs, each communication device (ODUXC device 20) updates the route information as appropriate so as to avoid the failure. Therefore, when transferring within the layer 1, there is a possibility that the message may be lost. . However, by transferring the message to the destination device via the layer 0 network in which no failure has occurred, the possibility of the message being lost can be reduced. In this way, high reliability of the in-band monitoring and control network that has been multi-layered by the integrated device can be realized, and even if a failure that affects the in-band monitoring and control network occurs, continuous device monitoring and control can be performed. Can be restored.

  In the transfer flow shown in FIG. 7, when the monitoring control frame is not reachable to the destination via another layer, the frame is discarded, but the monitoring control frame is sent to the link where no failure has occurred. You may make it forward. At this time, when a transfer is preferentially performed to a link to a communication apparatus having a transfer path to another layer (connected to a communication apparatus of another layer), the transfer is transferred from the transfer destination communication apparatus to the other layer. Since the possibility of reaching the destination is increased, the reliability can be improved. Whether or not the communication apparatus has a transfer path to another layer can be determined by referring to the column (d) of the path table shown in FIGS.

  As described above, the communication devices (OXC device 10 and ODUXC device 20) of the present embodiment include means (network IFs 127 and 227) for communicating with communication devices of other layers, and the communication devices of other layers are connected. In the case where the route information is advertised by the routing protocol, the ID of the own device and the ID of the communication device of another connected layer are given and advertised. When the route information advertised from another communication device is received, the route table held is updated, and when the update of the route table is completed, another layer connected to each other communication device in the same layer as the own device The communication device ID is notified to the communication device of the other layer connected to the own device. In addition, when the communication device ID of the own layer (the layer to which the own device belongs) connected to each of the other layer communication devices is notified from the other layer communication device connected to the own device. The notified ID is registered and updated in the routing table. As a result, when a monitoring control frame is received in a state where a failure has occurred in its own layer, the monitoring control frame can be transferred to the destination via another layer, and a highly reliable in-band monitoring control network can be established. realizable.

Embodiment 2. FIG.
The optical transmission system according to the second embodiment will be described. The configuration of the optical transmission system of the present embodiment is the same as that of the first embodiment (see FIG. 1). The configurations of the OXC device 10 and the ODUXC device 20 are the same as those in the first embodiment (see FIG. 2).

In the optical transmission system of the present embodiment, the gateway device (OXC device 10 ₁ , ODUXC device 20 ₁ ) of each layer notifies the network management device 1 of the route table (see FIG. 3 to FIG. 6) held by itself. The network management device 1 uses either the L0 in-band monitoring control network or the L1 in-band monitoring control network based on the stored route table (route table notified from the gateway device) when performing the monitoring control communication. Decide what to do.

  For example, when connection-type file transfer such as device setting information and firmware update file is performed, the bandwidth in the supervisory control network is occupied, and Trap and Get / Set responses by SNMP are discarded during file transfer. there is a possibility. For example, when the L1 in-band monitoring control network is used for updating the file of the ODUXC device, this problem is solved by performing the monitoring control of the device using the L0 in-band monitoring control network. In addition, the L0 in-band monitoring control network and the L1 in-band monitoring control network are simultaneously used for the monitoring control frame that affects the switching notification and the main signal, so that the reachability of the monitoring control frame is improved and the continuous device monitoring control is performed. It becomes possible.

  It should be noted that the gateway device in each layer notifies the network management device 1 of the routing table, and when the network management device 1 transmits the monitoring control frame, the implementation is performed except for control other than determining the network to be used based on the routing table. This is the same as the first embodiment. That is, the communication devices (OXC device 10 and ODUXC device 20) of each layer update the routing table in the same procedure as in the first embodiment, and a failure occurs in determining the transfer destination when the monitoring control frame is received. If not, it is transferred to the network of its own layer (the layer to which the communication device belongs). If a failure has occurred, if the destination can be reached via another layer, it is transferred to the communication device of the other layer.

  As described above, in the optical transmission system according to the present embodiment, the gateway device of each layer transmits the stored route table to the network management device 1, and the network management device 1 transmits frames other than the monitoring control frame. When transmitting to the layer communication device, the network to be used is selected based on the routing table received from the gateway device. Thereby, reliability can be improved.

  As described above, the communication apparatus according to the present invention is useful as a communication apparatus constituting an optical transmission network, and is particularly suitable for a communication apparatus having a communication interface with another layer of communication apparatus.

1 network management device, 2 DCN (Data Communication Network), 10 ₁ , 10 ₂ , 10 ₃ , 10 ₄ , 10 ₅ , 10 ₆ , 10 ₇ OXC device, 12, 22 device monitoring control unit, 13-1, 13- n transponder unit, 14 MUX / DEMUX unit, 15 OXC unit, 16-1, 16-2, 16-n AMP unit, 17-1, 17-2, 17-n OSC unit, 20 ₁ , 20 ₂ , 20 ₄ , 20 ₅ , 20 ₇ ODUXC device, 23-1, 23-n client signal accommodation unit, 24 XC unit, 25-1, 25-n line signal accommodation unit, 121 L0 path control unit, 122, 222 switching management unit, 123, 223 Failure management unit, 124 L0 path management unit, 125, 225 Configuration management unit, 126 L0 route control database, 127, 227 Network IF (NW IF), 221 L1 route Route control unit, 224 L1 path management unit, 226 L1 route control database.

Claims (8)

A communication device constituting a multi-layered optical transmission system,
Inter-layer communication means for communicating with another layer communication device that is a communication device of a layer different from itself,
Information management means for managing information on whether or not control frame transmission via the layer to which the other layer communication device belongs is possible for each of other communication devices in the same layer as itself;
Transfer destination determination means for determining a transfer destination when transferring a control frame transmitted to another communication device addressed to the same layer as itself based on information managed by the information management means;
A communication apparatus comprising:   The transfer destination determining means, when a failure has occurred in the transmission path with the next hop communication device in the path to the destination of the control frame, based on the information managed by the information management means, It is determined whether or not the control frame can be transmitted to its destination via another layer device connected to the inter-layer communication means, and if it can be transmitted, the control frame is connected to the inter-layer communication means. The communication apparatus according to claim 1, wherein the communication apparatus transfers to another layer apparatus.   The communication apparatus according to claim 1, wherein an in-band monitoring control network is formed. A first network formed by a first communication device in charge of communication in a first layer; a second network formed by a second communication device in charge of communication in a second layer; A network management device that manages one network and the second network, and the first communication device and the second communication device are configured to communicate with a communication device in a layer different from itself. An optical transmission system provided with communication means,
When the first communication device receives a first control frame that is a control frame transmitted to the communication device of the first network by the network management device, a failure has occurred in the route to the destination. For example, it is confirmed whether or not the first control frame can reach the destination via the second network. If the destination is reachable, the first control frame is transmitted to the second communication device connected to the inter-layer communication means. 1 control frame is transferred,
When the second communication device receives a second control frame that is a control frame transmitted to the communication device of the second network by the network management device, a failure has occurred in the route to the destination. For example, it is confirmed whether or not the second control frame can reach the destination via the first network. If the destination is reachable, the second control frame is sent to the first communication device connected to the inter-layer communication means. 2 transfer control frames,
An optical transmission system characterized by that. Of the first communication devices, a first gateway that operates as a gateway of the first network passes through the second network with respect to each of the other first communication devices belonging to the first network. Informs the network management device whether or not frame transmission is possible,
Among the second communication devices, a second gateway that operates as a gateway of the second network passes through the first network with respect to each of the other second communication devices belonging to the second network. Informs the network management device whether or not frame transmission is possible,
The network management device is configured to transmit a network to be used when transmitting a frame other than the first control frame and the second control frame in an optical transmission system, and the information notified from the first gateway and the second gateway. Select based on the information notified from
The optical transmission system according to claim 4. The network management device is configured to transmit a network to be used when transmitting a frame other than the first control frame and the second control frame in an optical transmission system, and the information notified from the first gateway and the second gateway. Selecting based on the information notified from, and the bandwidth usage status in the first network and the bandwidth usage status in the second network,
The optical transmission system according to claim 5.   The optical transmission system according to claim 4, 5 or 6, wherein the first network and the second network are in-band supervisory control networks. A first communication device responsible for communication in the first layer;
A second communication device responsible for communication in the second layer;
With
The first communication device and the second communication device include inter-layer communication means for communicating with each other,
When the first communication device receives a first control frame, which is a control frame in the first layer, if a failure has occurred in the route to the destination, the first control frame is changed to the second control frame. Confirming whether the destination can be reached via the layer, and if so, transferring the first control frame to the second communication device,
When the second communication device receives a second control frame, which is a control frame in the second layer, if a failure has occurred in a route to the destination, the second control frame is Check whether the destination can be reached via the layer, and if so, transfer the second control frame to the first communication device;
An optical transmission device characterized by that.

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