JP2012165110A - Optical transmission apparatus, management device, and optical transmission system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To facilitate the switching control of communication paths.SOLUTION: An optical transmission apparatus related to the present invention constitutes a network having multiple switchable communication paths and is arranged in a section where TCM (tandem connection monitoring) is set. The apparatus includes: a table for storing a TTI (trail trace identifier) value within a TCM area in the ODU (optical data unit) overhead of an OTN (optical transport network) frame and a data transmission destination after the switching of the communication paths, that are corresponding to each other; and a transmission part for transmitting data with the TTI value stored therein to the data transmission destination, based on the TTI value corresponding to the communication path of a switching destination and the data transmission destination, that are stored in the table, when the communication paths are switched.

Description

  The present invention relates to an optical transmission system using an OTN (Optical Transport Network) interface.

  ITU-T Recommendation G. 709 “Interfaces for the optical transport network” defines a standard for an optical transmission system using an OTN interface. In OTN, data multiplexed hierarchically by a WDM (Wavelength Division Multiplexing) method and a TDM (Time Division Multiplexing) method is transferred to an adjacent optical transmission apparatus. In the ODU (Optical Data Unit) hierarchy, TCM (Tandem Connection Monitoring) that divides a plurality of connections through a plurality of optical transmission apparatuses and enables alarm and performance monitoring for each divided section is defined.

  FIG. It is a figure which shows the format of the ODU overhead on 709 standard. FIG. It is a figure which shows the structure of the TCMi (i = 1-6) area | region in the ODU overhead on a 709 standard. As shown in FIG. 12, the ODU overhead is provided with a monitoring control area from TCM1 to TCM6. For this reason, monitoring control information can be transferred in parallel at a maximum of six levels on a link between adjacent optical transmission apparatuses, and alarms, performance, etc. can be monitored.

  In the conventional technique, the TCM is used to monitor the occurrence of a failure or congestion in a section where the communication path is switched by dividing the network into a plurality of sections (sub-networks). When a failure is detected in an optical transmission apparatus that is an end point of a section in which a TCM connection is set (hereinafter referred to as a TCM section), switching to a communication path in which no failure has occurred is performed. Since the switching control of the communication path requires an operation of switching the transfer destination by an optical switch or the like in each optical transmission device, the communication to be switched using a path control means such as GMPLS (Generalized Multi-Protocol Label Switching). The transfer state of each optical transmission device on the path is changed (for example, see Patent Document 1 below).

JP 2007-36412 A

  However, in the conventional technique described in Patent Document 1, when the telecommunications carrier or organization that manages the TCM section differs depending on the TCM section, the monitoring control information for managing a certain TCM section is different from the other telecommunications carrier. There is a problem that it is discarded or misprocessed while passing through another TCM section managed by the organization. For this reason, it is necessary to have a common control communication means between telecommunication carriers and organizations that manage the TCM section, to make it possible to mix even different control communication means, or to communicate separately for control communication There is a problem that it is necessary to take measures such as providing a route, and the switching control of the communication route becomes complicated.

  The present invention has been made in order to solve the above-described problems. When a failure or congestion occurs in the network, the TTI (Tail) in the TCM area of the ODU overhead is used as a control parameter for switching the communication path between the optical transmission apparatuses. It is an object of the present invention to simplify communication path switching control by utilizing a Trace Identifier value.

  An optical transmission apparatus according to the present invention is an optical transmission apparatus that constitutes a network having a plurality of switchable communication paths and is arranged in a section in which a TCM is set, and that is included in a TCM area in an ODU overhead of an OTN frame. A table that associates and stores a TTI value and a data transmission destination after switching the communication path, and the TTI that corresponds to the communication path that is the switching destination that is stored in the table when the communication path is switched. A transmission unit configured to transmit the data storing the TTI value to the data transmission destination based on the value and the data transmission destination.

  According to the present invention, communication path switching control can be simplified.

It is a figure which shows the structural example of the network concerning Embodiment 1 of this invention. It is a figure which shows the structural example of the optical transmission apparatus concerning Embodiment 1 of this invention. It is a figure which shows an example of the switch setting table before and behind the communication path switching of the optical transmission apparatus 2 concerning this Embodiment 1, a TTI reception reference table, and a path switching control table. It is a figure which shows an example of the switch setting table before and behind the communication path switching of the optical transmission apparatus 3 concerning this Embodiment 1, a TTI reception reference table, and a path switching control table. It is a figure which shows an example of the switch setting table before and behind the communication path switching of the optical transmission apparatus 4 concerning this Embodiment 1, a TTI reception reference table, and a path switching control table. It is a figure which shows an example of the switch setting table before and behind the communication path switching of the optical transmission apparatus 5 concerning this Embodiment 1, a TTI reception reference table, and a path switching control table. 6 is a flowchart illustrating an example of processing for switching communication paths in the optical transmission device serving as the transmission end of the TCM section according to the first embodiment of the present invention. 6 is a flowchart showing an example of processing for switching communication paths in the optical transmission device serving as a relay point or receiving end of a TCM section according to the first embodiment of the present invention; It is a figure which shows the structural example of the network concerning Embodiment 2 of this invention. It is a figure which shows an example of the TTI reception reference table of the optical transmission apparatus 35 concerning Embodiment 2 of this invention. It is a figure which shows the structural example of the network concerning Embodiment 3 of this invention. G. It is a figure which shows the format of the ODU overhead on 709 standard. G. It is a figure which shows the structure of the TCMi (i = 1-6) area | region in the ODU overhead on a 709 standard.

  Embodiments of the present invention will be described below in detail with reference to the drawings. Note that each of the embodiments described below is an embodiment for embodying the present invention, and is not intended to limit the present invention within the scope thereof.

Embodiment 1 FIG.
FIG. 1 is a diagram illustrating a configuration example of a network according to the present embodiment. As shown in the figure, in the network according to the present embodiment, client apparatuses 7 and 8 are connected via optical transmission apparatuses 1 to 6. The interfaces 21 to 29 for connecting the client device and the optical transmission device or the optical transmission device are realized by, for example, a pair of optical fibers for transmission and reception. A communication path for transmitting and receiving data between the client device 7 and the client device 8 is set so as to avoid failures and congestion occurring in the network. The management apparatus 11 monitors the optical transmission apparatuses 1 to 6 via the monitoring control network 12. In FIG. 1, as an example, the case of data transmission from the client device 7 to the client device 8 is shown.

  FIG. 2 is a diagram illustrating a configuration example of the optical transmission apparatus according to the present embodiment. As illustrated, the optical transmission device according to the present embodiment includes a path control unit 100, line interface units 200, 210, and 220, and a switch unit 300. Note that the configuration of each part in FIG. 2 is shown as an example for explaining the embodiment, and the mounting form of each part is not limited to this. For example, it is possible to modify such that the function of each unit is realized by a common hardware, or the function of each unit is realized by a plurality of hardware. The optical transmission apparatus in the following embodiments has the same configuration.

  The path control unit 100 includes a switch setting table 101, a TTI reception reference table 102, and a path switching control table 103. The contents of these tables are changed based on a request from the management apparatus 11. An arrow from the management apparatus 11 to each optical transmission apparatus in FIG. 1 indicates a request to change the table contents.

  The switch setting table 101 stores the current switch setting contents of the switch unit 300. The TTI reception reference table 102 is used to change the contents of the switch setting table 101 according to the TTI value in the TCM area in the ODU overhead of the OTN frame received by the line interface unit 200. The table also registers whether the optical transmission device is the receiving end of the TCM section. Based on this information, monitoring of signal transmission in the TCM section is started. The path switching control table 103 is a switch setting content of a switching destination communication path when switching from the communication path currently used at the end point of the TCM section to another communication path triggered by detection of a failure or the like. Is stored.

  The line interface unit 200 includes a TCM TTI reference unit 201, an OTN frame processing unit 202, and a buffer 203. The line interface unit 210 includes a TCM TTI setting unit 211 and an OTN frame generation unit 212. The line interface unit 220 has the same configuration as the line interface unit 210.

  Each of the line interface units 200, 210, and 220 transmits / receives data to / from an adjacent optical transmission device. For the sake of simplicity, FIG. 2 shows a configuration in which the line interface unit 200 receives data output from an adjacent optical transmission device, and a configuration in which the line interface unit 210 transmits data to the adjacent optical transmission device. Is shown. The line interface units 200, 210, and 220 may have both a configuration for receiving data output from an adjacent optical transmission device and a configuration for transmitting data to the adjacent optical transmission device. In the present embodiment, the line interface unit 200 is an example of a receiving unit. The line interface unit 210 is an example of a transmission unit.

  Next, the operation of the optical transmission apparatus will be described. The OTN frame processing unit 202 of the line interface unit 200 performs frame synchronization with respect to the data string and extracts an OTN frame. The TCM TTI reference unit 201 refers to the TTI value of the TCM area in the OTN frame. If the TTI value referred to here matches the TTI value stored in the TTI reception reference table 102, the received data is transferred to the data transmission destination associated with the matched TTI value. The buffer 203 temporarily holds the OTN frame. From the above reference, if the TTI values match, data is sent from the buffer 203 to the switch unit 300.

  The switch unit 300 transfers the data received by the line interface unit 200 to the line interface unit 210 or the line interface unit 220 based on the contents of the switch setting table 101.

  In the line interface units 210 and 220, the TCM TTI setting unit 211 sets a TTI value for the data transferred from the switch unit 300, and the OTN frame generation unit 212 generates an OTN frame from the data. The generated OTN frame is output to the outside.

  Next, the operation of the optical transmission apparatus when switching communication paths in the network configuration example shown in FIG. 1 will be described. In this description, the optical transmission device 1, the optical transmission device 2, the optical transmission device 5, the optical transmission device 1, the optical transmission device 2, the optical transmission device 4, and the optical transmission device 6, in order, An example of switching to a communication path that passes through the optical transmission device 4 and the optical transmission device 6 in order will be described.

  The management apparatus 11 registers the contents of each table of the path control unit 100 of the optical transmission apparatuses 2 to 5 in advance. For example, the tables of the optical transmission apparatuses 2 to 5 are set in advance so as to have the contents before the communication path switching shown in the upper part (a) of FIGS. The contents of each table can be updated in a timely manner according to the request of the management device 11 so as to correspond to the signal transmission status. The switch units 300 of the optical transmission apparatuses 2 to 5 transfer data based on the contents of the switch setting table 101.

  FIG. 3 is a diagram illustrating an example of a switch setting table, a TTI reception reference table, and a path switching control table before and after switching the communication path of the optical transmission device 2 according to the present embodiment. The upper part (a) of FIG. 3 shows the contents of each table before the communication path is switched, and the lower part (b) shows the contents of each table after the communication path is switched. The same applies to FIGS. 4, 5, and 6.

  The switch setting table 101 stores a reception interface number, a reception slot number, a transmission destination interface number, and a transmission destination slot number. The reception interface number indicates the number of an interface that receives data, and the transmission destination interface number indicates the number of an interface that is a data transmission destination. In this embodiment, for the sake of explanation, the transmission destination interface number and the reception interface number correspond to the reference numerals in FIG. The reception slot number indicates a time slot assigned to data to be received, and the transmission destination slot number indicates a time slot number assigned to data to be transmitted. In accordance with the switch setting table 101, the optical transmission device 2 transmits data received from the reception source specified by the reception interface number “22” and the time slot number “7” to the transmission destination interface number “23” and the time slot number “6”. "To the destination specified by. That is, before the communication path is switched, the optical transmission device 2 receives data from the optical transmission device 1 and transfers the data to the optical transmission device 3.

  The path switching control table 103 stores the TCM level, transmission TTI value, transmission destination interface number, transmission destination slot number, switching destination interface number, and switching destination slot number. When switching communication paths according to signal transmission conditions such as network failure and congestion, the destination interface and destination slot number in the switch setting table 101 are switched as shown in the lower part (b) of FIG. It is rewritten by the destination interface number and the switching destination slot number. The switching destination interface number is the number of the interface that is the data transmission destination after switching the communication path, and the switching destination slot number is the time slot number assigned to the data to be transmitted after switching the communication path. The switching destination interface number and the switching destination slot number are stored in the path switching control table 103 in association with the TCM level and the transmission TTI value. In the present embodiment, the path switching control table 103 stores the switching destination interface number “24” and the switching destination slot number “8”. In the optical transmission apparatus 2, when switching the data received from the optical transmission apparatus 1 from the communication path for transferring to the optical transmission apparatus 3 to the communication path for transferring to the optical transmission apparatus 5, the transmission destination interface number is changed from “23” to “ The transmission destination slot number is rewritten from “6” to “8”.

  The TCM level and the transmission TTI value are information used for switching the communication path. As shown in FIG. 3, the TCM level is “2”, and the transmission TTI value is AB_CD_EF. That is, the TTI value stored in the TCM 2 of the ODU overhead is a bit string representing AB_CD_EF when displayed as a character string. The character string AB_CD_EF is shown as an example, and any value may be used as long as it is a unique value for the TCM level to be used and its TCM section. That is, when a network is divided into several sections and one TCM level is used for one divided section (subnetwork), the TTI value corresponding to the TCM level is unique for each subnetwork. Value.

  In this embodiment, in order to identify the communication path to be switched, it is assumed that the TTI value is unique on the subnetwork, and the TTI value is associated with the communication path to be switched to. That is, when the subsequent device refers to the TTI value, the switch setting content is rewritten based on the TTI value, thereby realizing partial switching from the current communication path to another communication path.

  FIG. 4 is a diagram illustrating an example of a switch setting table, a TTI reception reference table, and a path switching control table before and after switching the communication path of the optical transmission device 3 according to the present embodiment. The switch setting table 101 stores a reception interface number “23”, a reception slot number “6”, a transmission destination interface number “25”, and a transmission destination slot number “5”. That is, the contents of receiving data from the optical transmission device 2 and transmitting the received data to the optical transmission device 4 are shown. When a destination other than the optical transmission device 4 is not designated as a transfer destination of the data received from the optical transmission device 2, nothing is stored in the TTI reception reference table 102 and the path switching control table 103 of the optical transmission device 3 as illustrated. It does not have to be.

  FIG. 5 is a diagram illustrating an example of a switch setting table, a TTI reception reference table, and a path switching control table before and after switching the communication path of the optical transmission device 4 according to the present embodiment. When the communication path is switched, the state of receiving data from the optical transmission device 3 is switched to the state of receiving data from the optical transmission device 5. Therefore, as shown in FIG. 5, the reception interface number in the switch setting table 101 is rewritten from “25” to “27”, and the reception slot number is rewritten from “5” to “7”.

  The TTI reception reference table 102 stores reception interface numbers, reception slot numbers, TCM levels, reception TTI values, transmission destination interface numbers, transmission destination slot numbers, and reception ends. In the same table, the receiving interface number and receiving slot number, the sending destination interface number and the sending destination slot number are assigned to the number of the interface corresponding to the sending or receiving source of the data after switching the communication path, respectively. The number of the assigned time slot. The reception TTI value is a TTI value expected to be extracted from the reception data in the TCM section. As shown in FIG. 5, the content of the TTI reception reference table 102 includes the TCM of the ODU overhead received from the reception source specified by the reception interface number “27” and the reception slot number “7” and extracted from the reception data. When the level is “2” and the TTI value is AB_CD_EF, this indicates that the received data is transferred to the destination specified by the destination interface number “28” and the destination slot number “1”. Also, “1” is stored if the optical transmission apparatus is the receiving end of the TCM section, and “0” is stored if it is not the receiving end. Since the optical transmission device 4 is the receiving end of the section of the TCM level “2”, the value “1” is stored.

  FIG. 6 is a diagram illustrating an example of a switch setting table, a TTI reception reference table, and a path switching control table before and after switching the communication path of the optical transmission apparatus 5 according to the present embodiment. As shown in the upper part (a) of FIG. 6, the content of the TTI reception reference table 102 is received from the reception source specified by the reception interface number “24” and the reception slot number “8”, and extracted from the reception data. When the TCM level in the ODU overhead of the OTN frame is 2 and the TTI value is AB_CD_EF, this indicates that transfer is performed to the transmission destination specified by the transmission destination interface number “27” and the transmission destination slot number “7”. As shown in the upper part (a) of FIG. 6, the switch setting table 101 before switching the communication path is empty because no data is transmitted or received. As shown in the lower part (b) of FIG. 6, the switch setting table 101 after the communication path switching has a reception interface number “24”, a reception slot number “8”, a transmission destination interface number “27”, a transmission destination slot number “ 7 ”is stored, indicating the content of receiving data from the optical transmission apparatus 2 and transferring the data to the optical transmission apparatus 4.

  Next, each operation of the optical transmission apparatus when a failure or congestion occurs in the TCM section will be described. In the present embodiment, the operation when a failure occurs in the transmission path between the optical transmission device 3 and the optical transmission device 4 and the optical transmission device 4 detects an optical input interruption will be described as an example. When detecting the optical input interruption, the optical transmission device 4 uses the BCM (Backward Detect Indication) of TCM2 (i = 2) shown in FIG. 13 to cause the optical transmission device 2 to recognize that a failure has occurred in the TCM section.

  The optical transmission apparatus 2 is a transmission end of communication path switching control information (transmission TTI value) in the TCM section. Next, processing for switching communication paths in the optical transmission device 2 will be described. FIG. 7 is a flowchart illustrating an example of a process of switching communication paths in the optical transmission apparatus that is the transmission end of the TCM section according to the present embodiment.

  As described above, the optical transmission device 2 detects a failure in the communication path such as optical input interruption in the network (step ST71). When the optical transmission device 2 detects a communication path failure, the optical transmission device 2 refers to the switching destination interface number and the switching destination slot number in the path switching control table 103 (step ST72), and switches the switching destination interface number and the switching destination slot. A number is acquired (step ST73). Next, the transmission TTI value registered in the path switching control table 103 is stored in the data to be transmitted, and transmission of the OTN frame generated from the data is started to the data transmission destination specified by the switching destination interface number (step ST74). At this time, the contents of the switch setting table 101 are updated by rewriting the transmission destination interface number and the transmission destination slot number with the switching destination interface number and the switching destination slot number (step ST75). Note that step ST74 and step ST75 may be performed in parallel, or the order of FIG. 7 may be reversed.

  As a result, as shown in the lower part (b) of FIG. 3, the contents of the switch setting table 101 are rewritten to the transmission destination interface number “24” and the transmission destination slot number “8”, and the data transfer destination is the optical transmission. The device 3 is switched to the optical transmission device 5. Also, the TTI value of TCM2 of ODU overhead is AB_CD_EF.

  Next, a description will be given of processing for switching communication paths in an optical transmission apparatus that is a relay point or a receiving end of a TCM section. In this embodiment, the optical transmission device 5 is the relay point of the TCM section, and the optical transmission device 4 is the reception end. FIG. 8 is a flowchart illustrating an example of a process of switching communication paths in the optical transmission apparatus serving as a relay point or reception end of the TCM section according to the present embodiment.

  The optical transmission apparatus receives the TTI value of the TCM area in the ODU overhead of the OTN frame extracted from the received data (step ST81). Next, the TTI value is a predetermined fixed value (0xFFFF or the like) indicating release, or the STAT value (PM status) in the TCM area is, for example, release of OCI (Open Connection Indication) “110” or the like It is determined whether the value indicates (ST811). If these indicate release, the switch setting is released for the reception interface number and the reception slot number corresponding to the reception source that received the data (step ST812), and the process ends. The data received at this time is not transferred to another optical transmission device. On the other hand, if they do not indicate release, the TTI reception reference table 102 is referred to (step ST82). Next, the optical transmission apparatus determines whether a TCM level and a TTI value that match the TCM level and TTI value extracted from the received data are registered in the TTI reception reference table 102 (step ST821). If the matching TCM level and TTI value are not registered, the received data is discarded (step 822), and the process ends. If the matching TCM level and TTI value are registered, the reception interface number, reception slot number, transmission destination interface number, and transmission destination slot number are acquired from the TTI reception reference table 102 (step ST83). Next, the optical transmission apparatus starts transmitting an OTN frame generated from this data to the acquired data transmission destination (step ST84). At this time, the contents of the switch setting table 101 are updated with the acquired reception interface number, reception slot number, transmission destination interface number, transmission destination slot number (step ST85). Also, the optical transmission apparatus determines from the TTI reception reference table 102 whether or not it is the receiving end of the TCM section (step ST831). When the value at the receiving end of the TTI reception reference table 102 is “1”, the reception expected TTI value expected to be received in the communication path after switching the received TTI value is the communication path of the TCM section. Monitoring of erroneous connection is started (step ST86). In addition, step ST84 and step ST85 may be performed in parallel, or the order may be reverse to FIG.

  With the above operation, the optical transmission device 5 receives the TTI value from the data and updates the switch setting table 101. As shown in the lower part (b) of FIG. 6, the contents of the switch setting table 101 are the reception interface number “24”, the reception slot number “8”, the transmission destination interface number “27”, and the transmission destination slot number “7”. The data received from the optical transmission device 2 is transferred to the optical transmission device 4. Further, the TTI value of TCM2 in the ODU overhead of the data to be transmitted is AB_CD_EF.

  Similarly, the optical transmission device 4 receives the TTI value from the data and updates the switch setting table 101. As shown in the lower part (b) of FIG. 5, the reception interface number is changed to “27” and the reception slot number “7”, and the switch setting table 101 is updated so as to receive data from the optical transmission apparatus 5. Furthermore, since the optical transmission device 4 is a receiving end, the reception TTI value is set as an expected reception TTI value expected to be extracted from the reception data in the communication path after switching. The TTI value extracted from the data received after switching the communication path is compared with the expected reception TTI value, and if they do not match, it is determined that an erroneous connection has occurred in the communication path. Thus, G. Error detection and comparison are performed using misconnection detection compared with the received TTI value based on the 709 standard and other areas in the TCM of the ODU overhead.

  As described above, when a failure occurs, the communication path that passes through the optical transmission device 2, the optical transmission device 3, and the optical transmission device 4 in order is the communication that passes through the optical transmission device 2, the optical transmission device 5, and the optical transmission device 4 in order. Switch to the route.

  As described above, when a failure or congestion occurs in the network, the TTI value of the TCM area in the ODU overhead of the OTN frame is used as a control parameter for switching the communication path, and the data transmission destination associated with the TTI value is a table. And the communication path is switched based on the TTI value. The TTI value is a unique value for each TCM section, and independent control communication can be performed for each TCM section. That is, since the TTI value of a certain TCM level is not referred to in a section in which another TCM level is set, there is no hindrance to control communication such as monitoring control information being discarded while passing through another TCM section. . Further, even if a plurality of TCM levels are set to overlap in a certain section, identification information such as an optical transmission device or an interface number as a data transfer destination can be determined for each TCM level, such as device identification information. There is no restriction to unify the specifications of control information. For this reason, even if the telecommunications carrier or organization that manages the TCM section is different depending on the TCM section, it does not interfere with the control communication of the other telecommunications carrier or organization, and the other telecommunications carrier or organization. There is no need for an agreement to unify the control information specifications. Thereby, the switching control of the communication path can be simplified. Furthermore, since the data transfer destination associated with the TTI value can be specified by reading the TTI value and collating the table, it is possible to realize high-speed switching of the communication path according to the signal transmission situation such as occurrence of a failure or congestion. It becomes possible. Further, after switching the communication path, the TTI information is used as it is for monitoring an erroneous connection of the communication path. Since TCM monitoring based on the 709 standard can be automatically continued, setting of a new TCM is not required, and operation after switching can be simplified.

Embodiment 2. FIG.
In the first embodiment, the contents registered in the TTI reception reference table 102 and the path switching control table 103 relate to one TCM level, but in the present embodiment, a plurality of contents are registered.

  FIG. 9 is a diagram illustrating a configuration example of a network according to the present embodiment. The communication path starting from the optical transmission apparatus 32 and the optical transmission apparatus 34 includes a communication path that passes through the optical transmission apparatus 32, the optical transmission apparatus 33, and the optical transmission apparatus 34 in order, and a failure in the interface 43. , The optical transmission device 32, the optical transmission device 35, the optical transmission device 33, the optical transmission device 34, the optical transmission device 32, the optical transmission device 35, the optical transmission And a communication path that passes through the device 36 and the optical transmission device 34 in this order.

  In such a communication path, as shown in the figure, a TCM1 connection is set in the communication path of the optical transmission device 32, the optical transmission device 35, the optical transmission device 36, and the optical transmission device 34. A TCM2 connection is set in the communication path of the transmission device 35 and the optical transmission device 33. A unique TTI value is set for the TCM levels “1” and “2” in the path switching control table 103 of the optical transmission apparatus 32, and data transmission is performed after switching the communication path associated with each TTI value. The previous contents are registered. Thus, when the optical transmission device 32 recognizes that a failure has occurred in the interface 43, the transmission TTI value of TCM2 is stored in the TCM TTI region, and the optical transmission device 32, the optical transmission device 35, and the optical transmission device 33 Switching to the sequential communication path is performed. When the optical transmission apparatus 32 recognizes that a failure has occurred in the interface 44, the transmission TTI value of TCM1 is stored in the TCM TTI area, and the optical transmission apparatus 32, optical transmission apparatus 35, optical transmission apparatus 36, optical Switching to the communication path in the order of the transmission device 34 is performed.

  The optical transmission apparatus 35 that has received data from the optical transmission apparatus 32 switches the communication path based on the TTI value extracted from the data. FIG. 10 is a diagram illustrating an example of a TTI reception reference table of the optical transmission apparatus 35 according to the present embodiment. As shown in the figure, the reception interface number “47” and the reception slot number “7” are common. However, when a failure occurs in the interface 44, the TCM level is “1” and the reception TTI value is AB_CD_EF. When a failure occurs in the interface 43, the TCM level is “2” and the reception TTI value is GH_IJ_KL. The received TTI value is a unique value according to the TCM level and its TCM section, as in the first embodiment. The optical transmission apparatus 35 transmits data to the data transmission destination specified by the transmission destination interface number and the transmission destination slot number corresponding to the TTI value extracted from the reception data. As described above, a desired switching operation can be realized in accordance with a signal transmission situation such as a network failure or congestion. In this embodiment, the contents registered in the TTI reception reference table 102 and the path switching control table 103 relate to two TCM levels and TTI values. However, when there are two or more communication paths to be switched, two are stored. It may be the above.

Embodiment 3 FIG.
If there is another communication path that uses the switching destination interface or time slot when switching the communication path, an erroneous connection of the communication path may occur. FIG. 11 is a diagram illustrating an example of a network configuration according to the present embodiment. A case where an erroneous connection occurs in the illustrated network will be described. For data transmission between the client device 66 and the client device 67, a low-priority communication path via the optical transmission device 64 and the optical transmission device 65 is set, and data transmission between the client device 68 and the client device 69 is performed. Therefore, a high-priority communication path that passes through the optical transmission device 61, the optical transmission device 62, and the optical transmission device 63 is set.

  It is assumed that a failure (for example, the interface 72 or the interface 73) occurs in the high-priority communication path, and the communication path is switched to a low-priority communication path. In this case, the transmission destination interface number and the transmission destination slot number in the switch setting table 101 of the optical transmission device 61, the optical transmission device 64, and the optical transmission device 65 are sequentially changed corresponding to switching of communication paths. However, in a state immediately after the switch setting table 101 of the optical transmission device 64 is changed, the data transmitted by the client device 68 is switched from the setting contents before the switching by the switch setting table 101 of the downstream optical transmission device 65. A state of being transferred to the client device 67 via the optical transmission device 61, the optical transmission device 64, and the optical transmission device 65 temporarily occurs until the setting contents are changed later.

  In order to avoid such an erroneous connection, when data is transferred to a time slot that has already been set in the optical transmission device 64, the OCI (ODU STAT value (PM Status) is 110 when the OTN frame is generated. A specific pattern for canceling the switch setting is inserted and transmitted. In this case, in the optical transmission device 65 on the downstream side of the optical transmission device 64, the switch setting is canceled by the operations of steps ST811 and ST812 in FIG. 8, and thus data is erroneously transferred to the client device 67. Can be prevented. Further, the buffer 203 is controlled so that the received TTI value data not registered in the TTI reception reference table 102 is discarded by the operation of step ST821 in FIG.

  As described above, when switching the communication path, a pattern for canceling the switch setting in the downstream optical transmission apparatus is inserted into the data transferred by the upstream optical transmission apparatus in the switching destination communication path. As a result, it is possible to prevent erroneous connection that occurs when the communication path is switched.

1-6 Optical transmission devices 7, 8 Client device 11 Management device 12 Monitoring control network 21-29 Interfaces 31-37 Optical transmission devices 38, 39 Client devices 41-50 Interfaces 61-65 Optical transmission devices 66-69 Client devices 71- 79 Interface 100 Path control unit 101 Switch setting table 102 TTI reception reference table 103 Path switching control tables 200, 210, 220 Line interface unit 201 TCM TTI reference unit 202 OTN frame processing unit 203 Buffer 211 TCM TTI setting unit 212 OTN frame generation unit 300 Switch part

Claims (9)

An optical transmission apparatus that constitutes a network having a plurality of switchable communication paths and is arranged in a section in which TCM (Tandem Connection Monitoring) is set,
A table that stores a TTI (Trail Trace Identifier) value in a TCM area in an ODU (Optical Data Unit) overhead of an OTN (Optical Transport Network) frame and a data transmission destination after switching the communication path in association with each other;
When switching the communication path, based on the TTI value corresponding to the switching destination communication path and the data transmission destination stored in the table, the data storing the TTI value is transmitted to the data transmission destination. An optical transmission device comprising: a transmission unit.   2. The table according to claim 1, wherein a plurality of different TTI values respectively corresponding to the communication paths serving as switching destinations and data transmission destinations after switching the communication paths are stored in association with each other. The optical transmission device described. An optical transmission apparatus that constitutes a network having a plurality of switchable communication paths and is arranged in a section in which TCM (Tandem Connection Monitoring) is set,
A receiver for receiving data;
A table that stores a TTI (Trail Trace Identifier) value in a TCM area in an ODU (Optical Data Unit) overhead of an OTN (Optical Transport Network) frame and a data transmission destination as a transfer destination of received data in association with each other;
A transmitting unit configured to transfer the received data to the data transmission destination associated with the TTI value in the table when the TTI value extracted from the received data matches the TTI value stored in the table; An optical transmission device comprising:   4. The table according to claim 3, wherein a plurality of different TTI values respectively corresponding to the communication paths that are switching destinations and data transmission destinations that are transfer destinations of the received data are stored in association with each other. 5. The optical transmission device described. The optical transmission device according to claim 3 or 4,
When the TCM at the same level is the end point of the set section, the TTI value stored in the table is compared with the TTI value extracted from the received data, and the communication path in the section is checked. An optical transmission device characterized by monitoring an erroneous connection. The optical transmission device according to any one of claims 3 to 5,
When the TTI value extracted from the received data is a value other than the TTI value stored in the table, or the setting for determining the transfer destination of the received data is canceled in the TCM area of the received data When the value to be stored is stored, the received data is not transferred. When switching to the communication path,
In the downstream optical transmission apparatus on the communication path after switching, the setting for determining the transfer destination of the received data of the optical transmission apparatus switches the communication path from the setting before switching the communication path. The data stored in the TCM area with a value for canceling the setting before switching the communication path is transmitted to the downstream optical transmission apparatus until it is updated to a later setting. The optical transmission device according to any one of 1 to 6.   The management apparatus which registers the said TTI value and the said data transmission destination with respect to the said table of the optical transmission apparatus of Claims 1 thru | or 7.   An optical transmission system, wherein the optical transmission device according to claim 1 is a transmission end, and the optical transmission device according to claim 3 is a relay point or a reception end.

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