JP3841811B2 - Path tracing method and apparatus - Google Patents

Description

  The present invention relates to a path tracing method and apparatus, and more particularly to a path tracing method and apparatus between line termination apparatuses.

  In recent years, an optical transmission network such as SONET / SDH has become a form in which a complex network of vendors is connected against the background of increasing demand for communication lines in the information society. In addition, the path path of the transmission path also realizes a complicated connection between paths by performing a digital cross-connect, but a function for preventing the erroneous setting of the cross-connect is required.

  FIG. 20 shows a conventionally known optical transmission network. Path terminating equipment (PTE: Path Terminating Equipment) 1 and 10 includes line terminating equipment (LTE: Line Terminating Equipment) 2 to 8 and an optical network NW1. The path termination device 1 belongs to the client side network NW2, and the path termination device 10 belongs to the client side network NW3.

  In such an optical transmission network, confirmation of misconfiguration of a cross-connect (not shown) in the line termination devices 2 to 8 or the optical network NW1, that is, confirmation of path conduction between the path termination devices 1-10 is shown in FIG. In contrast to the SONET / SDH transmission frame overhead generally shown in 1), the section overhead SOH, line overhead LOH, and path overhead as the termination overhead in the path termination equipment, as shown by the shaded area in (4) in the figure This can be done by using all of the POH and continuously inserting a fixed pattern (path trace code) into the J1 byte portion of the path overhead POH.

  In other words, as shown in Fig. 22, path trace can be performed between the path termination devices 1 and 10 using the J1 byte part, which enables confirmation of path continuity and confirmation of cross-connect misconfiguration. It becomes.

  Further, as the termination overhead in the line termination apparatuses 2 to 8 shown in FIG. 20, a section overhead SOH and a line overhead LOH are used as shown by the shaded portion in FIG. 21 (3).

  Furthermore, although not shown in FIG. 20, the section overhead in the section termination equipment (STE) shown in FIG. 22 uses only the section overhead SOH as shown by the shaded portion in FIG. 21 (2). In addition, by inserting a fixed continuous pattern (section trace code) into the J0 byte portion, section trace can be performed between the section termination devices 51-52 shown in FIG. 22, and optical fiber continuity can be confirmed. It becomes.

  On the other hand, when confirming continuity between arbitrary line termination devices in the line termination devices 2 to 8 shown in FIG. 20, the J1 byte portion shown in FIG. 21 is inserted with data as shown in FIG. Therefore, it is not possible to perform an intermediate path trace between line terminating devices (meaning an intermediate path trace between path terminating devices) using the J1 byte portion.

  However, although the J1 byte part cannot be inserted in this way in the line termination device, it is possible to extract the J1 byte part itself (GR-253-CORE ISSUE03 defines the function for reporting the contents of the J1 byte part. Data inserted in the J1 byte part extracted by any line terminator (path trace code) and data inserted in the J1 byte part extracted by any other line terminator It is possible to perform an intermediate path trace function by comparing

  However, in such a case, when the path trace is not performed between the path termination devices 1-10 using the J1 byte part, the path trace code is not inserted in the J1 byte part. The terminating device cannot receive the J1 byte data (intermediate path trace code), and the intermediate path trace cannot be performed between the line terminating devices.

  Furthermore, the intermediate path trace in the J1 byte part is UNEQ (line unused), the path overhead POH is all “0”, and the J1 byte part is also “0”, so the path trace code can be received. Disappear. This indicates that the path trace can be performed only after releasing the UNEQ, that is, setting the line connection and connecting to the client network when building the line.

  Therefore, if a line misconfiguration has occurred, a path trace is performed until the misconfiguration is discovered, resulting in a line misconnection state and the outflow of client data. To avoid this, it is necessary to enable path trace even when the line is in UNEQ state.

  In addition, when access to the client side information is prohibited, that is, extraction of the path overhead POH shown in Fig. 21 (4) may not be permitted. In this case, the path trace code in the J1 byte part cannot be received. The intermediate path trace cannot be performed between the line terminators.

  Furthermore, since the line overhead LOH (see FIG. 21 (3)) can be terminated in the line termination device, it is possible to insert / extract intermediate path trace codes from the line overhead LOH, but FIG. 23 (1) In the configuration of a general line termination device composed of the receiving unit 60, the cross-connect unit 61, and the transmitting unit 62 as shown in FIG. 4, the line overhead LOH received by the receiving unit 60 is changed to a new line overhead LOH by the transmitting unit 62. It is rewritten and transparent code transfer is not possible.

  Therefore, as shown in FIG. 2 (2), the code extraction unit 130 is connected to the S / LOH reception processing unit 11 in the reception unit 60 to extract the intermediate path trace code, and the cross connect 120 in the cross connection unit 61 The intermediate path trace code is converted by the code conversion unit 612 in response to the channel exchange of the code, and the code insertion unit 150 performs the transparent code transfer using an additional circuit in which the S / LOH transmission processing unit 44 inserts the code. It will be necessary.

  That is, since the path trace code added for each path is assigned to a different channel (time slot) after passing through the cross-connect, it is necessary to transmit the cross-connect information also by the transmission processing unit 44. In this case, if each function is divided by unit, a dedicated circuit (code extraction unit 130, code conversion unit 140, and code insertion unit 150) between the units is required, and this function is newly added Will need to change the circuit of various units.

<Prior art documents>
Japanese Patent Application Laid-Open No. 6-169311 includes route map processing for tracking transmission paths between stations, MUX map processing for tracking MUX connection paths at each station, and “Back to Back” in the connection paths within a station. In-station map processing that tracks the route corresponding to this “contact” when the network is connected, and change processing that changes the information indicating the starting point of tracking based on the “contact” structure when “contact” exists in the station. Thus, a transmission route tracking system for a transmission network is disclosed in which the transmission route between MUXs is traced and the route display is switched in accordance with the process switching.

  Therefore, the present invention does not perform a path trace using the J1 byte portion between the path termination devices in the optical transmission network, but performs an intermediate path trace between the line termination devices between the path termination devices to confirm the erroneous setting ( It is an object of the present invention to provide a method and an apparatus for performing continuity confirmation.

In order to achieve the above object, a path trace method according to the present invention includes a first step of inserting a predetermined trace code into a predetermined byte portion of a transmission frame format by a predetermined first line termination device, and a predetermined second And a second step of extracting the data of the predetermined byte portion and comparing the data with an expected value corresponding to the predetermined trace code, wherein the predetermined byte portion is a SONET / SDH system. It is characterized by the H3 byte part .

The present invention will be described with reference to FIG. 1. In a predetermined line terminating device (LTE) 3 located between path terminating devices 1-10, that is, a transmission terminating device, for example, as shown in FIG. Then, a predetermined trace code (intermediate path trace code) is inserted into the H3 byte portion of the SONET / SDH optical transmission system system as the predetermined byte portion of the transmission frame format and transmitted.

  Then, in the second line termination device 6 that is predetermined, that is, predetermined as the receiving side device, the data of the H3 byte portion is extracted, and this data, that is, the received value and the above-mentioned predetermined trace code in advance are extracted. Compare with the expected value prepared ((4) in the figure).

  As a result, when the two match, it is possible to confirm (conductivity confirmation) that there is no erroneous setting in the cross-connect.

  On the contrary, a predetermined trace code is inserted into the H3 byte portion by the line terminator 6 ((3) in the figure), and the expected value and the received value are compared by the line terminator 3 ((2) in the figure). It is also possible.

  In the above case, in the line terminator 4 located between the line terminators 3 and 6, transparent data transfer is realized with respect to the H3 byte part by passing the H3 byte part as it is.

  The first and second steps described above can be executed even when the path line is not set (not used).

  That is, when the path line is not set, the path overhead POH (including the J1 byte part) and payload shown in FIG. 21 (4) become “0”, and the path trace is also performed between the path terminating devices 1-10. However, since the H3 byte portion is used in the present invention, the data is not mapped to all “0” even when the H3 byte portion is not set. As with, intermediate path tracing is possible.

  In the first step, when a path alarm occurs (P-AIS), an alarm code can be inserted into a predetermined byte portion instead of a predetermined trace code.

  In other words, when a path alarm occurs, all “1” s are also mapped in the H3 byte part. Therefore, even in the case of the above-described invention, an alarm code such as all “1” is replaced with the H3 byte instead of the predetermined trace code. It will be inserted into the part.

  Therefore, in the second step, when such an alarm code is detected, unnecessary comparison operation between the data (reception value) of the predetermined H3 byte portion and the expected value is not performed.

  Considering the operation as described above, between the first and second line terminators, the first line terminator transmits a predetermined trace code in the first step, respectively, and the second line terminator Then, by extracting this as a received value and comparing the received value with the predetermined trace code itself to be transmitted by the second line terminating device itself as an expected value, the second step may be executed. Good.

  That is, in the second line termination device, instead of setting an expected value as a predetermined trace code in advance, by transmitting a predetermined trace code between the first and second line termination devices, The data can be compared with an expected value corresponding to a predetermined trace code.

  Furthermore, in the first step, when transmitting a concatenated signal, a predetermined trace code may be inserted into the H3 byte portion only for the first channel.

  In other words, since the cross connect is processed in units of concatenation, the intermediate trace code to the H3 byte part in the first step is premised on the assumption that the signals in the concatenation will not be cross connected. It is sufficient to insert only the first channel.

  Therefore, in the above second step, it is only necessary to compare the data detected only in the head channel at the time of receiving the concatenated signal with the expected value.

  Furthermore, in the above second step, even when a path alarm (P-AIS) signal is received, if the device does not support the predetermined byte part (H3 byte part), all the H3 byte parts have the same sign ( If all “1” or “0”), the path trace error signal can be prevented from being generated.

  In other words, in a line termination device that does not support the H3 byte part, all “1” (SDH system) or all “0” (SONET system) is mapped at the time of stuffing or when there is no stuffing / destuffing operation. As described above, when the data of the H3 byte portion has the same sign, even if the path alarm signal is detected, it is not always the case when the path alarm is generated, and therefore, an intermediate path trace error can be prevented from occurring.

  Furthermore, in the first step, a predetermined trace code can be inserted into the H3 byte portion corresponding to the variable frame length.

  Accordingly, in the second step, data may be extracted from the variable frame length accordingly.

  Further, in the present invention, when the comparison result in the second step is inconsistent, a third step of detecting a normal line termination device by looping back in another line termination device between both line termination devices is performed. It can also be provided.

  That is, in the above case, the presence / absence of an erroneous setting of the cross-connect can be determined, but it cannot be determined where the erroneous setting has occurred.

  Therefore, in the present invention, each line terminator is provided with a loopback function, and when the mismatch is determined in the second step, it is possible to determine how far the normal line terminator is by looping back the intermediate line terminator. I have to.

As a device of the present invention for realizing the path trace method according to the present invention as described above, a predetermined first line termination device for inserting a predetermined trace code into a predetermined byte portion of a transmission frame format, and data of the predetermined byte portion And a predetermined second line termination device that compares the data with an expected value corresponding to the predetermined trace code, and the predetermined byte portion is an H3 byte portion of the SONET / SDH system A path trace device is provided.

  In this path trace device, line termination devices other than both line termination devices can pass the predetermined byte portion as they are.

Their to, first and second line termination devices, also the path line unset time, it is possible to perform the insertion and comparison operations.

  In response, the first line termination device can insert an alarm code into the predetermined byte portion instead of the predetermined trace code when a path alarm occurs.

  Further, the second line terminating device may be configured not to perform the comparison when detecting the alarm code.

  In addition, both line terminating devices can transmit the predetermined trace code, respectively, and compare the detected data with the expected value transmitted by the own device.

  Further, the first line termination device may insert the predetermined trace code into the predetermined byte portion only for the head channel when a concatenation signal is generated.

  In response to this, the second line termination device can perform the comparison only for the head channel at the time of the concatenation signal.

  In addition, even when the second line termination device receives the path alarm signal, if the device does not support the predetermined byte portion, if the predetermined byte portion is all the same sign, It is also possible not to generate a path trace error signal.

  Further, the first line termination device can insert the predetermined trace code into the predetermined byte portion corresponding to the variable frame length.

  Further, the second line termination device can extract the data from the variable frame length.

Furthermore, the path trace device according to the present invention is configured such that when the comparison result in the second line termination device is inconsistent, a loopback is performed in another line termination device between the two line termination devices, thereby normal line termination. The device can be detected .

  FIG. 2 shows an embodiment of a line termination device used in the path trace method and apparatus according to the present invention. The line termination apparatus according to this embodiment is roughly similar to the conventional example shown in FIG. 23 (1), in which the S / LOH reception processing unit 11, the pointer (PTR) processing unit 100, the cross connect 30, and the pointer processing are performed. Unit 110 and S / LOH transmission processing unit 44.

  However, in this embodiment, a predetermined intermediate path trace code is inserted into and extracted from the H3 byte portion, which is a predetermined byte portion that can be terminated by the line terminating device.

  That is, the H3 byte portion is included in the area of the line overhead LOH (see FIG. 21 (3)), but since it is a pointer byte, it is not the S / LOH processing unit (see FIG. 23) but the pointer (PTR) processing unit ( The same). Therefore, it is possible to transparently transfer the received H3 byte part simply by adding a function to the pointer processing unit.

  For this reason, in the line termination device that implements the path trace method and apparatus according to the present invention, the pointer processing unit 100 on the receiving side includes the H1 / H2 extraction unit 12, the H3 extraction unit 13, the J1 counter 14, and the error. It consists of stick store (ES) 15, FIFO 16, comparator 17, write counter (WCTR) 18, phase comparator (PC), read counter (RCTR) 20, H1 / H2 inserter 21, and H3 inserter 22. ing.

  In addition, the transmission side pointer processing unit 110 includes an H1 / H2 extraction unit 32, an H3 extraction unit 33, a J1 counter 34, an elastic store 35, a FIFO 36, a write counter 38, a phase comparator 39, a read counter 40, and an H1 / H An H2 insertion portion 41, an H3 insertion portion 42, and a selector 43 are included.

  In the pointer processing unit 100, the H1 / H2 extraction unit 12 extracts the H1 and H2 byte portions in the frame received and processed by the S / LOH processing unit 11 and sends them to the J1 counter 14. The H3 extraction unit 13 extracts the H3 byte portion based on the H1 and H2 byte portions extracted by the H1 / H2 extraction unit 12 from the H3 byte portion in the frame received and processed by the S / LOH processing unit 11. That is, at the time of destuffing, since the payload is mapped to the H3 byte part, extraction of the H3 byte part is prohibited.

  The FIFO 16 adjusts the timing to the memory 15 when sending the H3 byte part extracted by the H3 extraction unit 13 to the H3 insertion part 22, that is, to transparently transfer the H3 byte part extracted from the input side to the output side. belongs to.

  Since the clock of the data written to the memory 15 and the data to be read are different, the timing is adjusted by reading the data of the H3 byte portion from the FIFO 16 by the writing system clock using the line clock.

  The J1 counter 14 gives the memory 15 the start position of the payload (SPE) from the H1 and H2 byte portions. The comparison unit 17 compares the expected value EC corresponding to a predetermined intermediate path trace code with the data in the H3 byte portion extracted by the H3 extraction unit 13 to determine the presence or absence of a path trace error.

  The write counter 18 is a counter for writing the payload data received and processed by the S / LOH processing unit 11 from the beginning of the payload indicated by the J1 counter 14 to the memory 15, and the phase comparator 19 reads the memory 15 The stuff / destuff notification signal is generated based on the phase difference between the read counter 20 and the write counter.

  The H1 / H2 insertion unit 21 inserts H1 and H2 byte portions into the payload data read from the memory 15 by the read counter 20 based on the stuff / destuff notification signal from the phase comparator 19. The H3 insertion unit 22 writes the H3 byte part read from the FIFO 16 to the H3 byte position of the line overhead LOH. At this time, since valid data is inserted at the time of destuffing, the trace code to the H3 byte part Is prohibited.

  In the pointer processing unit 110, the H1 / H2 extraction unit 32 corresponds to the H1 / H2 extraction unit 12 in the pointer processing unit 100, the H3 extraction unit 33 is the H3 extraction unit 13, the J1 counter 34 is the J1 counter 44, the elastic Store 35 is elastic store 15, FIFO 36 is FIFO 16, write counter 38 is write counter 18, phase comparator 39 is phase comparator 19, read counter 40 is read counter 20, and H1 / H2 insertion section 41 is H1 / H2. The insertion part 21 and the H3 insertion part 42 correspond to the H3 insertion part 22, respectively.

  However, in the case of the pointer processing unit 110 on the transmission side, the H3 byte portion from the FIFO 36 and the (intermediate) path trace code PTC are selected by the selector 43 and sent to the H3 insertion unit 42. The point is different. The path trace code PTC and the path trace code expected value EC are corresponding code data.

  The line termination device (LTE) shown in FIG. 2 is separately the network management system side whether it is a transmitting station, a receiving station, or an intermediate station located between the transmitting station and the receiving station. The operation is different based on this.

  FIG. 3 is a diagram for explaining the operation of the transmitting station in this case, FIG. 4 is a diagram for explaining the operation in the intermediate station, and FIG. 5 is a diagram for explaining the operation in the receiving station. However, in all cases, the configuration itself is the same.

  First, in FIG. 3, the selector 43 in the pointer processing unit 110 on the transmission side selects a predetermined path trace code PTC, not the H3 byte portion from the FIFO 36, and sends it to the H3 insertion unit. As a result, the H3 insertion unit 42 inserts a predetermined trace code PTC into the H3 byte portion and transmits it from the S / LOH processing unit 44. This corresponds to the pointer processing unit 110 in the line termination device 3 in the example of FIG.

  The transmission frame sent from the line termination device 3 shown in FIG. 1 is transferred in the line termination device performing the operation shown in FIG.

  That is, the H1 / H2 extraction unit 12 extracts the H1 and H2 byte portions from the frame received and processed by the S / LOH processing unit 11, and the H3 extraction unit 13 extracts the H3 byte portion based on this.

  The extracted data is inserted into the H3 byte portion by the H3 insertion unit 22 via the FIFO 16 and sent to the cross-connect unit 30.

  The H1 and H2 byte parts are extracted by the H1 / H2 extraction unit 32 and the H3 byte part is extracted by the H3 extraction unit 33 from the frame that has passed through the cross-connect unit 30. The data inserted in the H3 byte portion is sent to the selector 43 via the FIFO 36.

  At this time, in this line termination device as an intermediate station, since the selector 43 is controlled to select the FIFO 36 side, the data from the FIFO 36 is sent to the H3 insertion unit 42 via the selector 43, It is inserted into the H3 byte part and transmitted from the S / LOH processing unit 44.

  In this way, the data in the H3 byte portion is transferred transparently in the intermediate line terminating device. The line termination device in this case corresponds to the line termination device 4 in FIG.

  FIG. 5 is for explaining the operation of the line termination device 6 as the receiving station shown in FIG. In this embodiment, from the frame received and processed by the S / LOH processing unit 11, the data inserted in the H3 byte portion is extracted by the H3 extraction unit 13 and sent to the comparison unit 17.

  The comparison unit 17 compares the path trace code expected value EC prepared in advance with the data from the H3 extraction unit 13, and if they match, it can be confirmed that there is no misconfiguration in the cross-connect (normal line). In the case of mismatch, it can be confirmed that there is a misconfiguration in some cross-connect.

  3 and 4 also compares the path trace code expected value EC with the extracted data from the H3 extraction unit 13, but the comparison unit 17 operates as a receiving station. The operation is not performed except when instructed in the above, and the coincidence and disagreement of both do not appear as a result.

  The above embodiment deals with a state where the line has already been set (when the line is not used). However, when the line is not set, the path overhead POH ( (Including the J1 byte part) and the payload are all “0”, and the path termination based on the J1 byte part cannot be performed even in the path terminating device (see the path terminating devices 1 and 10 in FIG. 1). .

  Therefore, normally, the path trace can be performed only after the line is set, and when the line is not set, the line is provided to the client without confirming the continuity of the path.

  On the other hand, since the path trace method and apparatus according to the present invention uses the H3 byte portion, even when the line is not set, the data in the H3 byte portion is not mapped to all “0”, so that path trace is possible. Become. A line construction example in this case will be described below with reference to FIG.

 (1) In the line terminating device 2, the line setting with the path terminating device 1 of the client side network NW2 is set to UNEQ (path line not set).

 (2) In the line termination device 8, the line setting is set to UNEQ in the same manner.

 (3) Set up an internal network cross-connect from the client-side network NW2. In this state, frame data with all “0” in the path overhead POH is input to the line termination device set to UNEQ, but since the path trace code PTC is mapped to the H3 byte part, the expected value, received value and Can be compared.

 (4) After confirming the continuity of the path using such a path trace method, cancel UNEQ, set the line, and provide the line to the client without any line misconnection.

  On the other hand, when a path alarm (P-AIS) occurs, all “1” is mapped not only in the payload (SPE) but also in the H3 byte portion as shown by the shaded portion in the transmission frame format of FIG. .

  Therefore, even if a path trace code is inserted upstream when a path alarm occurs, if an error occurs in the line termination device LTE on the way, all “1” is mapped in the H3 byte part by the path alarm processing. As a result, the comparison unit 17 cannot compare and match the expected value with the received value.

  Therefore, in the embodiment according to the present invention, when all “1” is received in the H3 byte portion when the path alarm occurs, the comparison operation in the comparison unit 17 is not performed.

  FIG. 9 shows a path alarm generation processing system on the transmission side in this case. In addition to the H1 / H2 insertion unit 41, a P-AIS control unit 45 is connected to the H3 insertion unit.

  That is, when the P-AIS control unit 45 detects the occurrence of a path alarm, the H3 byte portion in the H3 insertion unit 42 is controlled to insert “1”. Other operations are the same as those in FIGS.

  FIG. 10 shows a reception system corresponding to the transmission system shown in FIG. That is, when the path alarm occurs, all “1” is detected in the H1 / H2 extraction unit 12 in the H1 and H2 byte portions. At this time, the P-AIS detection unit 23 determines that the path alarm is generated. Thus, the comparison unit 17 stops comparing the data in the H3 byte portion from the H3 extraction unit 13 and the path trace code expected value EC. Accordingly, the comparison result is not output from the comparison unit 17 regardless of the coincidence / disagreement between the received data and the expected value.

  In the above embodiment, the comparison unit 17 is provided with a path trace code expected value EC prepared in advance and detects a match / mismatch with the received data value. In the case of the embodiment shown in FIG. Can check path continuity (intermediate path trace) using transmission data from the transmission-side line termination device and the reception-side termination device.

  That is, as shown in FIG. 1, when performing an intermediate path trace from the line terminator (LTE) 2 to the line terminator 8, when the line setting is normal as shown in FIG. 11 (1), the line terminator When a predetermined trace code inserted from 2 to the H3 byte part is transmitted as “AAAAAA” (step S1), the line terminating device 3 extracts the H3 byte part from this predetermined trace code “AAAAAA” (step S2). The trace code “AAAAAA” is again inserted into the H3 byte portion via the cross connect 30 (step S3).

  Similarly, the trace code “AAAAAA” is transferred transparently through the line terminators 4, 6 and 7 from step S4 to S9, and the trace code “AAAAAA” is transmitted from the H3 byte portion in the line terminator 8 on the receiving side. It will be extracted (step S10).

  On the other hand, the line terminator 8 also functions as a line terminator on the transmission side, and inserts the same trace code “AAAAAA” in the H3 byte portion (step S12), and the line terminators 7, 6, and 4 by steps S13 to S20. , 3, the trace code “AAAAAA” is extracted from the H3 byte part in the line terminating device 2 on the receiving side (step S 21).

  As a result, in the line terminating device 2, the data “AAAAAA” inserted in step S1 is compared with the data “AAAAAA” extracted in step S21 (step S22). In 30, it is possible to confirm the continuity of the intermediate path that the normal line setting is performed.

  On the other hand, as shown in FIG. 2 (2), in the case where the cross connect 30 misconfigures the channel CH1 and the channel CH2 in the line termination device 6, the trace code “ In the case of sending by inserting “AAAAAA”, when reaching the line termination device 6 via the line termination devices 3 and 4, the trace code “AAAAAA” is extracted in the H3 byte part in step S6, but in step S7 Since the channel is incorrectly set in the cross connect 30, the data “BBBBBB” is extracted in the H3 byte portion, and when this is sent to the line terminating device 8 via the line terminating device 7, in step S10 Will receive data “BBBBBB” from the H3 byte.

  Therefore, in the comparison in step S11, since data “AAAAAA” ≠ data “BBBBBB”, it is found that the cross-connect is erroneously set.

  On the other hand, when the line terminator 8 sets and sends the trace code “AAAAAA” and is sent to the line terminator 2 via the line terminators 7, 6, 4, and 3, the H3 byte portion is used in step S21. The extracted data is “BBBBBB”, and the transmission data and the reception data also do not match in step S22, so that the line termination apparatus 2 can also confirm the cross-connect misconfiguration.

  As described above, when the continuity confirmation of the intermediate path is also performed on the transmitting side, the line maintenance can be easily performed without performing the remote access to the line terminating device on the receiving side and confirming the path trace code.

  In the case of the above embodiment, a predetermined trace code is inserted into the H3 byte portion and extracted, assuming that the cross-connect is set for each channel separately. In the case of the concatenation signal as shown in FIG. 6, since the processing is performed in units of concatenation, the signals in the concatenation are not set to be cross-connected.

  Therefore, in order to simplify the insertion and extraction of data in the H3 byte part and the comparison function, or to reduce the circuit function, when the STS-Nc concatenation signal is input, the expected value judgment is performed only for the first channel. This makes it possible to avoid processing the H3 byte portion of the subordinate channel.

  Therefore, as shown in FIG. 13, on the transmission side of the line terminating device, when the concatenation control unit 46 is connected to the H3 insertion unit 42 and this concatenation control unit 46 detects that it is a concatenation signal, Insert the H3 byte into the first channel of the signal.

  As shown in FIG. 12, in the case of the STS48c concatenated signal, it is sufficient to insert an intermediate path trace code in the H3 byte portion for only channel ch01 as shown in FIG. In the case of a concatenated signal, it is only necessary to insert a trace code in the H3 byte portion only in ch01, ch13, ch25, and ch37 as the first channel. The same applies to the STS3c concatenated signal shown in FIG. 3 (3), and intermediate path trace codes may be inserted at intervals of three channels.

  FIG. 14 shows a configuration for receiving the intermediate path trace code of the H3 byte portion inserted only in the first channel of the concatenated signal in this way.

  That is, in addition to the received value from the H3 extraction unit 13 and the path trace code expected value EC, the comparison unit 17 is connected to the concatenation determination unit 24, and the concatenation determination unit 24 extracts the H1 extracted by the H1 / H2 extraction unit 12. If the received signal is found to be a concatenated signal from the H2 byte portion, the operation of the comparison unit 17 can be simplified by providing the comparison unit 17 with a control signal for comparing only the leading channel.

  Note that the transmission unit in FIG. 13 inserts all “1” s in the H3 byte portion of the subordinate channel, and the receiving side shown in FIG. 14 does not perform the processing of the H3 byte portion of the subordinate channel.

  In the case of the above embodiment, it is assumed that the line terminator supports the H3 byte part as in the SONET / SDH system, but the line terminator on the receiving side does not support the H3 byte part. It is necessary to consider that.

  In other words, the H3 byte part of a normal line termination device inserts a payload during destuffing regardless of whether or not H3 byte processing is supported, but the line termination device is a device that does not support the H3 byte part. When staffing as shown in Fig. 15 (1) or without staff / destuffing operation as shown in Fig. 15 (2), all "1" is mapped in the SDH system, and all "0" is mapped in the SONET system. The Rukoto.

  Therefore, when a line termination device that does not support H3 byte partial processing exists in the path for performing intermediate path tracing, all “1” or “0” is inserted in this H3 byte portion. There is a possibility of misjudging when a path alarm occurs (when PIP-AIS occurs).

  Therefore, as shown in FIG. 16, when the H / H2 extraction unit 12 extracts the H1 and H2 byte portions and the P-AIS detection unit 23 determines that the path alarm state is present, in this embodiment, the embodiment of FIG. Like this, the comparison unit 17 is not directly controlled.

  Therefore, when the comparison result of the comparison unit 17 is given to the mask unit 26, and the mask unit 26 determines that the data extracted by the H3 extraction unit 13 is all “1” or “0” in the detection unit 25 In this case, the mask unit 26 masks the path trace error signal (TIM-P: STS Path Trace Identifier Mismatch) from the comparison unit 17 because it is not in the path alarm state, so that the H3 byte partial passing function is provided in the middle of the path. Eliminates alarm errors of line termination equipment that you do not have.

  In the case of a line terminator that supports the H3 byte part, ASCII code is used, and all “1” or “0” is not used. Therefore, there is a line terminator that does not support H3 byte part processing. It is possible to distinguish whether there is between path traces.

  In the above embodiment, it is assumed that the H3 byte portion is inserted and extracted in a normal single frame. However, the present invention is not limited to this, and the present invention can also be applied to a multi-frame pattern.

  That is, in the case of the multi-frame pattern format, as shown in FIG. 17, byte # 1 indicates the multi-frame pattern, byte # 2 indicates the frame length, and bytes # 3 to #N indicate the expected path trace code. An ASCII code indicating the value EC is inserted.

  FIG. 18 (1) shows an operation example of the H3 insertion unit that inserts such a multi-frame as a path trace code, and FIG. 18 (2) shows an operation example of the H3 extraction unit. Has been.

  As shown in (1) of the figure, on the path trace code transmission side, after the operation starts (step S101), the multi-frame pattern is inserted into byte # 1 (step S102), and the frame length is further inserted into byte # 2. (Step S103), and the path trace code is inserted into bytes # 3 to #N (Step S104). As a result, an N-byte intermediate path trace code can be inserted.

  Then, it is determined whether or not writing has been completed up to the instructed frame length (step S105), and this is executed until completion, and after completion, the process returns to step S102.

  On the receiving side of the path trace code shown in FIG. 2 (2), after the operation is started (step S111), it is detected by byte # 1 whether it is a multi-frame pattern (step S112). An N-byte path trace code is written into the memory according to the frame length shown in 2 (step S113). An intermediate path trace code can be extracted by combining these N-byte path trace codes.

  In the case of the above embodiment, when an intermediate path trace is executed from the line terminating device on the transmission side to the line terminating device on the receiving side, somewhere between the two line terminating devices depending on the result of collation between the received data value and the expected value. It can be seen that the cross-connect is erroneously connected (erroneous line setting), but it is not known which cross-connect has failed.

  From this point of view, in the embodiment shown in FIG. 19, it is possible to confirm how far the cross-connect has been set.

  That is, for example, as shown in the figure, when a misconfiguration failure occurs in the cross-connect 30 of the line termination device 6, by using the loopback function of the H3 byte part, up to the cross-connection of any line termination device in the following procedure Check if is set correctly.

 (1) In the line terminating device 8 on the receiving side, a mismatch between the expected value and the received value occurs in step S11.

 (2) Set “H3 byte partial loopback setting” in the multi-frame format of the H3 byte part to “enable”.

 (3) When the line terminating device 7, 6, 4, 3 on the receiving side receives the “H3 byte partial loopback setting” in the multi-frame format of the H3 byte part as “enabled”, it receives the received H3 The byte part is loopback inserted into the H3 byte part on the transmitting side (steps S38, S36, S34, S32).

  That is, the line terminator 8 inserts a predetermined intermediate path trace code into the H3 byte part in step S12 and sends it to the line terminator 7. The line terminator 7 extracts the H3 byte part in step S13 and performs cross-connect. Since the data is sent to 30 and the loopback function is set (step S38), the data inserted in the H3 byte portion is further inserted into the H3 byte portion in step S9 and looped back to the line terminating device 8.

  In this case, “H3 byte partial loopback setting” of the loopback multi-frame pattern is set to “disabled”.

 (4) Since the cross connect 30 of the line terminator 7 is normal, the data of the H3 byte portion returned to the line terminator 8 matches the data on the transmission side. Therefore, when the line terminator 6 next extracts the H3 byte part in step S15 and inserts the H3 byte part in step S7 using the loopback function (step S36), the expected value and the received value also match. .

  However, for the data that has been looped back through steps S17, S34, and S5 in the line termination device 4, the line termination device 8 does not match both, so the line termination device 8 It can be seen that the cross connect 30 is set incorrectly.

  The same applies to the line terminating device 2 on the transmission side, and the trace code is inserted into the H3 byte portion from step S1 and transmitted, and then returned via the line terminating devices 3, 4, 6, and 7. Since the data extracted in step S21 is inconsistent (step S22), the above loop back command is issued and the same operation as the above line terminating device 8 is performed, so that the line terminating devices 3 and 4 are crossed. Since the connection 30 is normal, it can be confirmed that a failure has occurred in the line terminating device 6.

  As described above, according to the path trace method and apparatus according to the present invention, a predetermined trace code is inserted into a predetermined byte portion of a transmission frame format by a predetermined first line termination device, and a predetermined second line termination is performed. Since the apparatus extracts the data of the predetermined byte portion and compares the data with the expected value corresponding to the predetermined trace code, even when the path trace is not performed between the path termination apparatuses, An intermediate path trace between any line termination devices can be realized using bytes.

  In addition, since the line terminator other than the line terminator on the transmitting side and the receiving side passes the predetermined byte part as it is, transparent trace code transfer can be performed without using line overhead and without requiring an additional circuit. Can be done.

It is the schematic for demonstrating operation | movement of the path trace method and apparatus concerning this invention. It is the block diagram which showed one Example of the line termination apparatus used for the path trace method and apparatus which concerns on this invention. FIG. 3 is a diagram for explaining an operation when the line termination device constitutes a transmission station in the embodiment shown in FIG. 2; FIG. 3 is a diagram for explaining an operation when the line termination device constitutes an intermediate station in the embodiment shown in FIG. 2; FIG. 3 is a diagram for explaining an operation when the line termination device constitutes a receiving station in the embodiment shown in FIG. 2; FIG. 6 is a format diagram showing a frame data state when a path line is not set in the embodiment of the path trace method and apparatus according to the present invention. It is the schematic for demonstrating the operation | movement of this invention when a path line is not set. It is the format figure which showed the mapping state of the frame data at the time of a path alarm (at the time of P-AIS). It is the block diagram which expanded and showed partially the transmission side of the path trace method and apparatus based on this invention at the time of path | pass alarm generation | occurrence | production. FIG. 10 is a block diagram showing a receiving side portion corresponding to FIG. In the path trace method and apparatus according to the present invention, it is a diagram showing an embodiment in which an intermediate path trace is performed by transmitting a trace code from both line terminating devices. It is a figure for demonstrating the concatenated signal used for the path trace method and apparatus which concerns on this invention. It is the block diagram which expanded and showed partially the transmission side of the path trace method and apparatus based on this invention at the time of a concatenation signal. FIG. 14 is a block diagram showing a receiving side portion corresponding to FIG. FIG. 4 is a frame format diagram showing how H3 bytes are mapped according to the presence or absence of stuffing and destuffing in a transmission system that does not support H3 bytes. FIG. 16 is a block diagram showing an embodiment in which a path trace error does not occur even when a path alarm signal is received corresponding to the frame format shown in FIG. It is a pattern format figure at the time of applying the path trace method and apparatus based on this invention also to multi-frame. FIG. 18 is a flowchart for transmitting and receiving the multi-frame pattern of FIG. In the path trace method and apparatus according to the present invention, it is a diagram showing an embodiment for detecting a fault portion of the cross-connect using a loopback function. It is the schematic which showed the operation | movement which performs the path conduction | electrical_connection confirmation (path trace) between the path | route termination apparatuses known conventionally. It is a figure for demonstrating the overhead in the frame format of a SONET / SDH optical transmission system. It is a block diagram showing a path trace system and a section trace system. It is a block diagram for demonstrating the conventional and the path trace method and apparatus of this invention.

Explanation of symbols

1,10 path termination equipment (PTE)
2 to 8 line terminator (LTE)
NW1-NW3 network
11, 44 S / LOH processing section
12, 32 H1 / H2 extractor
13, 33 H3 extractor
14, 34 J1 counter
15, 35 Elastic Store (ES)
16, 36 FIFO
17, Comparison part
18, 38 Write counter (WCTR)
19, 39 Phase comparator
20, 40 Read counter (RCTR)
21, 41 H1 / H2 insertion part
22, 42 H3 insertion part
43 Selector (SEL)
100, 110 Pointer processing unit (PTR)
23 P-AIS detector
45 P-AIS controller
24 Concatenation judgment part
46 Concat control unit
26 Mask part
60 Transmitter
61 Cross-connect section
62 Transmitter
In the cross-connect diagram, the same reference numerals indicate the same or corresponding parts.

Claims (24)

A first step of inserting a predetermined trace code into a predetermined byte portion of the transmission frame format at a predetermined first line termination device;
A second step of extracting data of the predetermined byte portion with a predetermined second line termination device and comparing the data with an expected value corresponding to the predetermined trace code;
And the predetermined byte portion is a SONET / SDH H3 byte portion . In claim 1,
A path tracing method characterized in that a line terminating device other than both line terminating devices passes the predetermined byte portion as it is. In claim 1,
A path tracing method characterized by executing the first and second steps even when a path line is not set. In claim 1,
The first step is a path tracing method characterized in that an alarm code is inserted into the predetermined byte portion instead of the predetermined trace code when a path alarm occurs. In claim 4 ,
The path tracing method, wherein the second step is not executed when the alarm code is detected. In claim 1,
Both line termination devices transmit the predetermined trace code in the first step, and execute the second step by comparing the detected data with the predetermined trace code transmitted by the own device. A path tracing method characterized. In claim 1,
In the path tracing method, the first step includes inserting the predetermined trace code into the predetermined byte portion only in the head channel when a concatenation signal is generated. In claim 7 ,
The path tracing method characterized in that the second step performs the comparison only for the head channel when the concatenation signal is used. In claim 5 ,
In the second step, even when the path alarm signal is received, if the device does not support the predetermined byte part, if the predetermined byte part is all the same sign, an intermediate path trace error signal is generated. A path tracing method characterized by preventing occurrence. In claim 1,
The path tracing method characterized in that the first step inserts the predetermined trace code into the predetermined byte portion corresponding to a variable frame length. In claim 10 ,
The path tracing method, wherein the second step extracts the data from the variable frame length. In claim 6 ,
And a third step of detecting a normal line termination device by looping back at another line termination device between the image line termination devices when the comparison result in the second step does not match. And path trace method. A predetermined first line terminator for inserting a predetermined trace code in a predetermined byte portion of the transmission frame format;
A predetermined second line termination device that extracts data of the predetermined byte portion and compares the data with an expected value corresponding to the predetermined trace code;
And the predetermined byte portion is a SONET / SDH H3 byte portion . In claim 13 ,
A path trace device characterized in that the line terminator other than both line terminators passes the predetermined byte portion as it is. In claim 13 ,
The path trace apparatus characterized in that the first and second line terminators execute the insertion and comparison operations even when the path line is not set. In claim 13 ,
The path trace device, wherein the first line termination device inserts an alarm code into the predetermined byte portion instead of the predetermined trace code when a path alarm occurs. In claim 16 ,
A path trace device characterized in that the second line termination device does not perform the comparison when the alarm code is detected. In claim 13 ,
Both line terminating devices transmit the predetermined trace code, respectively, and compare the detected data with the expected value. In claim 13 ,
The path trace device, wherein the first line termination device inserts the predetermined trace code into the predetermined byte portion only for the head channel when a concatenation signal is present. In claim 19 ,
The path trace device, wherein the second line termination device performs the comparison only on the head channel when the concatenation signal is present. In claim 17 ,
Even when the second line termination device receives the path alarm signal, if the device does not support the predetermined byte portion, if the predetermined byte portion is all the same sign, the intermediate path trace A path trace device characterized in that an error signal is not generated. In claim 13 ,
The path trace device, wherein the first line terminator inserts the predetermined trace code into the predetermined byte portion corresponding to a variable frame length. In claim 22 ,
The path trace device, wherein the second line termination device extracts the data from the variable frame length. In claim 18 ,
A path trace characterized by detecting a normal line termination device by causing a loopback in another line termination device between the two line termination devices when the comparison result in the second line termination device is inconsistent. apparatus.

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