JP4381886B2 - Extended virtual path switching system - Google Patents

Description

  The present invention relates to an extended virtual path switching system in an ATM network. More specifically, the present invention relates to a plurality of transmission apparatuses (hereinafter referred to as NEF) that constitute a transmission path, and an operation system that executes monitoring control of the plurality of transmission apparatuses ( The present invention relates to a system that performs switching control for realizing high reliability in a virtual path (hereinafter referred to as VP) of an ATM network and high-speed recovery in the event of a VP failure.

  An ATM (Asynchronous Transfer Mode) network employs a VP (virtual path) switching method in order to achieve high reliability and high-speed recovery when a working line fails. The VP switching method enables the automatic switching to the normal system when a failure occurs in the line or interface by setting the working line and the protection spare line for each duplexing target line when constructing the ATM network. ing. In addition, when it is necessary to switch the working line such as during maintenance, the switching is intentionally suppressed or switched.

  The configuration shown in FIG. 1 is a basic configuration example of an ATM (Asynchronous Transfer Mode) network. As an example, transmission apparatuses 1 and 2 (hereinafter referred to as NEF # 1 and # 2) are connected by physical transmission paths PATH-A and B. Furthermore, it is connected to the operation system (OpS) 4 through the control network 3 (refer patent document 1).

  In FIG. 1, each of NEF # 1, # 2 and operation system (OpS) 4 has a VP management table shown in FIGS. 1 (A), (B), (C).

  In the setting before the VP switching shown in FIG. 1, the line managed by NEF # 1 is as follows. As shown in FIG. 1A, the termination point (P-U-A) of user A and the path termination of transmission path PATH-A A line CH1 that connects the points P-1-A and a line CH2 that connects the termination point (P-U-A) of the user A and the path termination point P-1-B of the transmission path PATH-B.

  As shown in FIG. 1B, the line managed by NEF # 2 is a line CH3 that connects the termination point (P-UB) of the user B and the path termination point P-2-A of the transmission path PATH-A. And a line CH4 that connects the termination point (P-U-B) of the user B and the path termination point P-2-B of the transmission path PATH-B.

  Lines CH1 and CH3 are working lines, and lines CH2 and CH4 are set as protection lines.

  On the other hand, the lines managed by OpS4 are the line CH1 and the line CH3 for the transmission path PATH-A, and the line CH2 and the line CH4 for the transmission path PATH-B.

  FIG. 2 is a sequence in the prior art in which a working line and a protection line are set from OpS4 to NEF # 1 and NEF # 2.

  As shown in FIG. 1, the protection line (PU-A = P) is previously set for the working line (P-U-A = P-1-A = P-2-A = P-U-B). −1−B = P−2−B = P−U−B) is assigned, the following switching operation is performed.

  FIG. 2-S1: When a failure occurs in the transmission line PATH-A of the working line, a reception alarm is detected at the path termination point P-2-A of NEF # 2.

  At this time, the “line state” of No. 1 in the VP management table (FIG. 1B) of NEF # 2 in FIG. 1 changes to “failing”.

  FIG. 2-S2: NEF # 2 refers to the VP management table No. 2 shown in FIG. 2B, and determines whether switching is possible from “line information” and “line state”. In this determination, if the “line state” of the protection line in “line information” is normal, the switchability check = OK, and the process of FIG. On the other hand, when the “line state” of the protection line in “line information” is out of order, the switchability check = NG.

  Switch failure notification data (P-2-B = P-U-B) is assigned to the command section in the parameter section of “OpS-NEF interface frame format” shown in FIG. 3 for NEF # 2 to OpS4. And the sequence ends.

  FIG. 2-S3: For NEF # 2 to NEF # 1, the kxky bit of the “VP-APS cell format” shown in FIG. 4 is set as shown in FIG. 4A, and the protection line (P-1-B = P-2-B), a request for switching to the transmission path PATH-B (PU-A = P-1-B), which is a protection line of NEF # 1, is sent out.

  FIG. 2 -S4: NEF # 1 is in the state of failure of "line status" of the "line information" working line in "VP-APS cell format" of FIG. 4 from NEF # 2 and transmission path PATH-B which is a protection line A switching request to (P-U-A = P-1-B) is received.

  At this time, the “line state” in the VP management table No. 1 of NEF # 1 in FIG. 1A changes to “failing”.

  FIG. 2-S5: NEF # 1 changes the working line from the transmission path PATH-A (PUA-P = P-1-A) to the protection line transmission path PATH-B (P-) by its own VPMDX control. Switch to UA = P-1-B). At this time, the “line information” in the VP management table No. 1 of the NEF # 1 in FIG. 1 changes to “protection line”, and the “line information” in No. 2 changes to “working line”.

  FIG. 2-S6: For NEF # 1 to NEF # 2, a switching response is set to kxky of “VP-APS cell format” of FIG. 4 as shown in FIG. B = P-2-B) is used to send a request for switching to transmission path PATH-B (P-2-B = PUB), which is a protection line for NEF # 2.

  FIG. 2-S7: For NEF # 1 to OpS4, the switch completion notification data (PUA = P-1-B) is sent to the command part in the parameter part of “OpS-NEF interface frame format” in FIG. ) And send.

  FIG. 2-S8: NEF # 2 switches from NEF # 1 to the transmission path PATH-B (P-2-B = P-U-B) which is a protection line in the "VP-APS cell format" of FIG. Receive a response.

  FIG. 2-S9: NEF # 2 changes the working line from the transmission path PATH-A (P-2-A = PUB) to the protection line transmission path PATH-B (P- 2-B = P−U−B). At this point, the transmission line is restored. At this time, the “line information” in the VP management table No. 1 of the NEF # 2 in FIG. 1B changes to “protection line”, and the “line information” in the VP management table No. 2 changes to “working line”. .

  2-S10: For NEF # 2 to OpS4, the switch completion notification data (P-2-B = P-U-B) is sent to the command section in the parameter section of “OpS-NEF interface frame format” in FIG. ) And send. At this time, the “line information” in the VP management table No. 1 of OpS 4 in FIG. 1C changes to “protection line”, and the “line information” in the VP management table No. 2 in OpS 4 changes to “working line”. .

FIG. 5 is a diagram showing a mode after switching when the switching operation is performed as described above.
JP-A-8-340335

  However, in the switching operation in the conventional method, switching is performed when the assigned protection line (PUA = P-1-B = P-2-B = PUB) has failed. It was impossible to rescue the working line.

  Accordingly, it is an object of the present invention to provide an extended VP switching system that enables a working line to be relieved even when an assigned protection line is out of order.

  The first aspect of the extended VP switching system that achieves the above-mentioned object of the present invention is the monitoring control of the plurality of transmission devices by connecting the plurality of transmission devices constituting the transmission path to the plurality of transmission devices through a control network. When the operation line that connects the own station transmission apparatus and the opposite station transmission apparatus is switched to the protection line, the protection line is assigned to the active line of the virtual path of the ATM network in advance, and the operation line is switched to the protection line. When the protection line is faulty, the local station transmission apparatus and the opposite station transmission apparatus can relieve the working line by searching for and assigning an empty protection line from the same transmission path virtual path as the protection line. And

  A second aspect of the extended virtual path switching system that achieves the above-described object of the present invention is the monitoring of the plurality of transmission devices by connecting the plurality of transmission devices constituting the transmission path and the plurality of transmission devices through a control network. When having an operation system that performs control, preliminarily assigning a protection line to the working path of the virtual path of the ATM network, and switching the working line connecting the local station transmission apparatus and the opposite station transmission apparatus to the protection line, When the protection line is faulty, the operation system can relieve the working line by searching for and assigning an empty protection line from the same path transmission path PATH as the protection line.

  According to a third aspect of the extended virtual path switching system for achieving the object of the present invention, a plurality of transmission devices constituting a transmission path are connected to the plurality of transmission devices through a control network, and the plurality of transmission devices are monitored. When having an operation system that performs control, preliminarily assigning a protection line to the working path of the virtual path of the ATM network, and switching the working line connecting the local station transmission apparatus and the opposite station transmission apparatus to the protection line, When the protection line is faulty, the operation system can relieve the working line by searching for and assigning a spare protection line having the same termination attribute as the protection line.

  According to a fourth aspect of the extended virtual path switching system for achieving the above-mentioned object of the present invention, in the third aspect, the idle spare line having the same termination attribute as the spare line includes the local station transmission apparatus and the opposite station transmission apparatus. Is a line that passes through another transmission device.

  The features of the present invention will become more apparent from the embodiments described below with reference to the drawings.

  In accordance with the present invention, when the assigned protection line is broken, the active line can be relieved by searching for and assigning an empty protection line from another route, and further, high-speed recovery can be realized. In addition, the reliability of the communication line is improved. In addition, it is possible to effectively utilize transmission lines and VPs that are not allocated.

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

  Here, a configuration example of the operation system OpS and the transmission apparatus NEF common to the embodiments of the present invention described below will be described first.

  FIG. 6 is a diagram illustrating a configuration example of OpS 4 and a connection form between OpS 4 and a plurality of transmission apparatuses NEF (# 1-# n) by control network 3.

[Input / output unit 40]
The input / output unit 40 in the OpS 4 includes an input unit 40-1 connected to a keyboard and a mouse and an output unit 40-2 connected to a CRT device. The input / output unit 40 has a GUI (Graphical User Interface) with an operator (operator), inputs / outputs control commands to / from each NEF # 1- # n, and monitoring information and redundant unit switching information of each NEF. Event information is output.

[Monitoring control application unit 41]
The supervisory control application unit 41 controls communication between NEFs for control commands (IF registration command, soft strap command, VP / VC setting command, etc.) to each NEF input from the operator (operator) to the input unit 40-1. This is executed for each NEF via the unit 42. The control command response sent from each NEF is output to the output unit 40-2 to notify the operator.

  In addition, event information (alarm, switching notification, etc.) issued autonomously from each NEF is received via the inter-NEF communication control unit 42. The received event information is output to the output unit 40-2 to notify the operator.

  The operation information according to the execution result of the control command for each NEF is updated in the NEF BU information backup unit (DB) 43. In the NEF BU information backup unit (DB) 43, the operation data on each NEF side stored in each NEF is periodically collected via the inter-NEF communication control unit 42, and the NEF BU information backup unit. (DB) 43 is stored in backup units # 1BU to # 4BU corresponding to each NEF.

[Non-NEF communication control unit 42]
The inter-NEF communication control unit 42 transmits the control command executed from the monitoring control application unit 41 to the corresponding NEF. In addition, a control command response is received from the corresponding NEF and notified to the monitoring control application unit 41. Further, the inter-NEF communication control unit 42 receives event information issued from each NEF and notifies the monitoring control application unit 41 of the event information.

[BU information backup unit (DB) 43 in NEF]
The NEF BU information backup unit (DB) 43 stores backup information in each NEF that is collected periodically as a BU file (binary data file). The setting state in each NEF that is changed as needed by the execution of the control command for each NEF is stored in the database 43. The update location and update data in the database are specified by the monitoring control application unit 41.

  FIG. 7 shows a configuration example of a NEF connected to the OpS 4 through the control network 3 and has the following functions.

[Setting process]
When a setting command is transmitted from the OpS 4 to the NEF, as a basic operation, the NEF confirms the normality of the setting command received by the LAN 100 of the SEMF-IF unit 10 by the CPU (control processing unit) 101, and the SEMF-IF unit. 10 to SVCONT unit 11 through bus interface unit 102. In the received SVCONT unit 11, the normality is confirmed by a CPU (alarm monitoring processing unit) 111 and set to the corresponding interface IF through the bus interface unit 112.

[Alarm detection processing]
The SVCONT unit 11 periodically polls the controlled package 12 and collects alarms in a CPU (alarm monitoring processing unit) 111. The SEMF-IF unit 10 periodically polls the SVCONT unit 11, converts the collected data, and notifies the OpS4. Issuing alarms (geological output, monitoring control IF transfer, overhead lamp, FAIL lamp lighting) can be prohibited by soft strap command.

[VP switching process]
In VP switching, there are a case where a line or a controlled package breaks down and NEF autonomous switching is executed, or a case where the switching is forcibly executed by a command from OpS4. When the line or the controlled package 12 fails, the SVCONT unit collects alarms by periodic polling and sends them to the SEMF-IF unit 10. The SEMF-IF unit 10 confirms normality by a CPU (control processing unit) 101, sends a switching request from the SVCONT unit 11 to the controlled package 12 through the bus interface unit 102, and performs switching.

  When a forced switching command is transmitted from OpS 4, the SEMF-IF unit 10 that has received the command confirms normality by the CPU (control processing unit) 101, and sends it from the SEMF-IF unit 10 to the SVCONT unit 11 through the bus interface unit 102. To do. The SVCONT unit 11 confirms normality by a CPU (alarm monitoring processing unit) 111 and sends a forced switching command to the controlled package 12 through the bus interface face unit 112.

[SEMF-IF section FILE second generation management]
When the operation information is lost due to a disaster or other event, the NEF operation information is backed up to a file (FILE) 103 in order to restart the NEF and start operation. The backup file (FILE) 103-2 is written by the regular write process and the mirroring command, and the current file (FILE) 103-1 is written by the recovery command.

  6 and 7, the information is transmitted and received between the OpS 4 and the NEF using the interface frame format shown in FIG.

  In the frame format of FIG. 3, the communication header has a fixed length of 16 bytes at the header portion placed at the head of the frame, and carries only information necessary for communication. The common part is a common part of the message, has a fixed length of 16 bytes, and carries an operation identifier, class identifier, and instance identifier defined by NEF. Further, the parameter part is a part (attribute identifier, attribute value) defined for each operation, and the operation and response in each class and instance are different. Therefore, the parameter part has a variable length to enable a plurality of operations.

  Command part is 01 search request data, 02 search result response data, 03 switching completion notification data, 04 switching failure notification data, 05 other road switching search request data, 06 other road switching search result response data, 07 other road switching It includes setting data, execution result response data for 08 other-path switching setting, 09 line setting data, and execution result response data for 10 line setting.

  Embodiments of the present invention that are realized by using the constituent functions of the above-described apparatuses will be described below.

  FIG. 8 shows a configuration example (before VP switching) of the ATM network according to the first embodiment of the present invention and the state of the VP management table, and FIG. 9 shows a configuration of the ATM network after VP switching and the VP management table. It is a figure which shows the state of. The first embodiment is an example in which switching is performed mainly by a NEF, and FIG. 10 is an operation sequence diagram thereof. The operation of the first embodiment will be described below with reference to FIG.

  For the working line (P-U-A = P-1-A = P-2-A = P-U-B), the protection line (P-U-A = P-1-B = P-2) in advance. −B = P−U−B) is allocated, and it is not possible to switch to the protection line (P−U−A = P−1−B = P−2−B = P−U−B). Free line (P-1-B ′ = P−2) of the same line (transmission path PATH-B) as the line (P−U−A = P−1−B = P−2−B = P−U−B) This is an example of performing the switching operation to -B ′).

  10-S1-1: When a failure occurs in the transmission line PATH-A of the working line, a reception alarm is detected at the user termination point P-2-A of NEF # 2. As a result, the “line state” in the VP management table No. 1 of NEF # 2 in FIG. 9B changes to “failing”.

  10-S1-2: NEF # 2 refers to the VP management table No. 2 of NEF # 2 in FIG. 7B, determines whether switching is possible from “line information” and “line state”, and “ The line information “protection line” “line status” failure is detected and switching to the protection line becomes impossible. As a result, the “line information” in the VP management table No. 2 of NEF # 2 in FIG. 8 changes to “unusable” (see FIG. 9B).

  10-S1-3: NEF # 2 refers to VP management table No. 3 of NEF # 2 in FIG. 8B, and determines whether switching is possible from “line information” and “line state”. When the “line information” is an empty line and the “line state” is normal, the switchability check is OK, and the processing of FIG. 10-S1-4 is performed.

  When there is no free line of “line information” or “line state” is not normal, the switchability check = NG. From NEF # 2 to OpS4, the switch failure notification data (P-2-B = PUB) is added to the command part in the parameter part of the interface frame format between OpS and NEF in FIG. This ends the sequence.

  10-S1-4: From NEF # 2 to NEF # 1, a switching request is set to kxky of the VP-APS cell format shown in FIG. 4 as shown in FIG. “B ′” of P-2-B ′ is stored as switching information in an empty area 1 Byte (APS RSV) of the cell, and an empty line (P-1-B ′ = P-2-B ′) is used. A switch request is sent to NEF # 1.

  10-S1-5: NEF # 1 receives the switching information “B ′” from NEF # 2 when the “line state” of the working line “line information” is failed in the VP-APS cell format of FIG. Accordingly, the “line state” in the VP management table No. 1 of NEF # 1 in FIG. 8A changes to “failing” (FIG. 9A).

  FIG. 10-S1-6: NEF # 1 receives the switching information “B ′” received from the transmission path PATH-A (PUA = P-1-A) through the working line by the VPMDX control of the local station. The transmission line is switched to the transmission path PATH-B (PUA = P-1-B ′) of the same line as the stored protection line. The “line information” in the VP management table No. 1 of the NEF # 1 in FIG. 8A is set to “unusable”, the “line information” in the VP management table No. 2 is set to “unusable”, and the VP management table No. The “line information” in .3 changes to “working line” (FIG. 9A).

  FIG. 10-S1-7: For NEF # 1 to NEF # 2, set the switching response to kxky of the VP-APS cell format of FIG. 4 as shown in FIG. “B ′” of P-2-B ′ is stored as switching information in an empty area 1 Byte (APS RSV), and NEF # is used using an empty line (P-1-B ′ = P-2-B ′). A switch request is sent to 2.

  10-S1-8: For NEF # 1 to OpS4, switch completion notification data (PUA = P-1-B) is sent to the command part in the parameter part of the interface frame format between OpS and NEF of FIG. ') Is added and sent.

  10-S1-9: NEF # 2 receives the switching information “B ′” from NEF # 1 in the VP-APS cell format of FIG. The NEF # 2 uses a protection line storing the received switching information “B ′” from the transmission path PATH-A (P-2-A = PUB) by the VPMDX control of its own station. Switch to the transmission line PATH-B (P-2-B ′ = PUB) of the same line. At this point, the transmission line is restored.

  10-S1-10: “Line information” in the VP management table No. 1 of NEF # 2 in FIG. 8B is set to “unusable”, and “Line information” in the VP management table No. 3 is “working line”. To change.

  FIG. 10-S1-11: For NEF # 2 to OpS4, the switch completion notification data (P-2-B ′ = PU−) is sent to the command part in the parameter part of the interface frame format between OpS and NEF of FIG. B) is added and sent. As a result, the “line information” in the VP management table No. 1 of OpS 4 in FIG. 8C is changed to “unusable”, the “line information” in the VP management table No. 2 is changed to “unusable”, and the VP management table No. The "line information" in .3 changes to "working line". With the above procedure, the basic configuration diagram of FIG. 8 becomes the basic configuration diagram of FIG. 9 after the completion of switching.

  As described above, in the first embodiment, opposing NEFs search for a free line that can be switched to the same line, and the line is relieved based on the result. Switch to the protection line NG, without stopping the processing, add connection destination transmission device information to the VP management table managed by NEF, and switch information to the VP-APS cell format free space 1 ByteE (APS RSV) in FIG. And a process for searching for a free line on the same line as the protection line is added to the NEF.

  FIG. 11 shows a configuration example of the ATM network (before VP switching) and the state of the VP management table according to the second embodiment of the present invention, and FIG. 12 shows the configuration of the ATM network after VP switching and the VP management table. It is a figure which shows the state of. The second embodiment is also an example in which switching is performed mainly by the NEF, and FIG. 13 is an operation sequence diagram thereof. The operation of the second embodiment will be described below with reference to FIG.

  For the working line (P-U-A = P-1-A = P-2-A = P-U-B), the protection line (P-U-A = P-1-B = P-2) in advance. −B = P−U−B) is allocated, the switch to the protection line (P−U−A = P−1−B = P−2−B = P−U−B) cannot be made and the protection line Free line (P-1-C = P-) of the same path line (transmission path PATH-C) as the line (P-U-A = P-1-B = P-2-B = P-U-B) The switching operation to 2-C) is performed.

  FIG. 13-S2-1: When a failure occurs in the transmission line PATH-A of the working line, a reception alarm is detected at P-2-A of NEF # 2. Therefore, the “line status” in the VP management table No. 1 of NEF # 2 in FIG. 11B changes to “failing” (FIG. 12B).

  FIG. 13-S2-2: NEF # 2 refers to the VP management table No.2 of NEF # 2 in FIG. 11B, determines whether switching is possible from “line information” and “line state”. The information "protection line" "line status" failure is detected and switching to the protection line is impossible. Therefore, the “line information” in the VP management table No. 2 of NEF # 2 in FIG. 11B changes to “unusable” (FIG. 12B).

  13-S2-3: For NEF # 2 to OpS4, search request data (P-2-B = P-U-B) in the command part in the parameter part of the interface frame format between OpS and NEF in FIG. And a search request for whether there is an empty line in the same route line as the protection line is transmitted.

  FIG. 13-S2-4: OpS4 receives the search request data (P-2-B = P-U-B) from NEF # 2 as to whether there is an empty line in the same route line as the protection line.

  13-S2-5: OpS4 refers to VP management table No. 2 of OpS4 in FIG. 11C from the received search request data (P-2-B = P-U-B), and is managed by OpS4. The transmission apparatus connected from the connected line recognizes NEF # 1 = NEF # 2. OpS4 searches the VP management table of OpS4 in FIG. 11C for a free line of the line information of NEF # 1 = NEF # 2, and transmits the transmission path PATH-C (NEF # 1 (P -U-A = P-1-C) = NEF # 2 (P-2-C = P-U-B) is detected.

  FIG. 13-S2-6: For OpS4 to NEF # 2, search result data (P-2-C = PUB) in the command part in the parameter part of the interface frame format between OpS and NEF in FIG. Is sent, and a search result is sent out as to whether there is an empty line in the same route line as the protection line.

  FIG. 13-S2-7: NEF # 2 is a search result from OpS4, and an empty line (P-2-C = PU−) in the same path line as the protection line in the OpS-NEF interface frame format of FIG. B) is received.

  13-S2-8: NEF # 2 refers to the VP management table No. 3 of NEF # 2 in FIG. 11B, and determines whether switching is possible from “line information” and “line state”. If the “line status” of the “line information” vacant line is normal, the switchability check = OK, and the process of FIG. 13-S2-9 is performed.

  If there is no free line in the “line information” or the “line state” is not normal, the switchability check = NG. From NEF # 2 to OpS4, the switch failure notification data (P-2-B = PUB) is added to the command part in the parameter part of the interface frame format between OpS and NEF in FIG. This ends the sequence.

  FIG. 13-S2-9: For NEF # 2 to NEF # 1, set a switching request to kxky in the VP-APS cell format of FIG. 4 as shown in FIG. “C” of P-2-C is stored as switching information in area 1 Byte (APS RSV), and a switching request is sent to NEF # 1 using an empty line (P-1-C = P-2-C). Send it out.

  FIG. 13-S2-10: NEF # 1 receives switching information “C” from NEF # 2 when the “line information” working line “line state” is in failure in the VP-APS cell format of FIG. Therefore, the “line status” in the VP management table No. 1 of NEF # 1 in FIG. 11A changes to “failing” (FIG. 12A).

  FIG. 13-S2-11: NEF # 1 stores the switching information “C” received from the transmission path PATH-A (PU-A = P-1-A) on the working line by the VPMDX control of the local station. The transmission line is switched to the transmission path PATH-C (PU-A = P-1-C) of the same path line as the protection line being operated. The “line information” in the VP management table No. 1 of the NEF # 1 in FIG. 11A is set to “unusable”, the “line information” in No. 2 is set to “unusable”, "Changes to" working line "(FIG. 12A).

  FIG. 13-S2-12: For NEF # 1 to NEF # 2, set the switching response to kxky in the VP-APS cell format of FIG. 4 as shown in FIG. P-2-C “C” is stored as switching information in area 1 Byte E (APS RSV), and a switching request is made to NEF # 2 using an empty line (P-1-C = P-2-C). Send it out.

  13-S2-13: For NEF # 1 to OpS4, the switch completion notification data (PUA = P-1-C) is sent to the command part in the parameter part of the interface frame format between OpS and NEF of FIG. ) And send.

  13-S2-14: NEF # 2 receives the switching information “C” from NEF # 1 in the VP-APS cell format of FIG.

  FIG. 13-S2-15: NEF # 2 stores the switching information “C” received from the transmission path PATH-A (P-2-A = PUB) on the working line by the VPMDX control of its own station. The transmission line is switched to the transmission path PATH-C (P-1-C = P-2-C) of the same path line as the protection line being operated.

At this point, the transmission line is restored. At this time, the “line information” in the VP management table No. 1 of the NEF # 2 in FIG. 11B changes to “unusable”, and the “line information” in the VP management table No. 3 changes to “working line”. .
13-S2-16: For NEF # 2 to OpS4, the switch completion notification data (P-2-C = P-U-B) is sent to the command part in the parameter part of the interface frame format between OpS and NEF in FIG. ) And send. 11B, “Line information” in the VP management table No. 1 of OpS4 is set to “unusable”, “Line information” in VP management table No. 2 is set to “unusable”, and VP management table No. 3 The “line information” changes to “working line”. The basic configuration diagram of FIG. 11 becomes the basic configuration diagram of FIG. 12 after the completion of switching.

  As described above, in the second embodiment, as a feature, the connection destination transmission apparatus information is added to the VP management table managed by the NEF without stopping the processing by the switching to the protection line NG. Switching information is added to the empty area 1BYTE (APS RSV) in the VP-APS cell format, and processing for searching for an empty spare line on the same route line as the spare line is added to OpS4.

  FIG. 14 shows a configuration example of the ATM network (before VP switching) and the state of the VP management table according to the third embodiment of the present invention, and FIG. 15 shows the configuration of the ATM network after the VP switching and the VP management table. It is a figure which shows the state of. The third embodiment is an example in which switching is performed mainly by the OpS, and FIG. 16 is an operation sequence diagram thereof. The operation of the third embodiment will be described below with reference to FIG.

  For the working line (P-U-A = P-1-A = P-2-A = P-U-B), the protection line (P-U-A = P-1-B = P-2) in advance. −B = P−U−B) is allocated, the switch to the protection line (P−U−A = P−1−B = P−2−B = P−U−B) cannot be made and the protection line Free line (P-1) of the same line termination (transmission path PATH-D = transmission path PATH-E) as the line (P-U = P-1-B = P-2-B = P-U-B) -D = P-3-D = P-3-E = P-2-E).

  FIG. 16-S3-1: When a failure occurs in the transmission line PATH-A of the working line, a reception alarm is detected at P-2-A of NEF # 2. The “line state” in the VP management table No. 1 of NEF # 2 in FIG. 14B changes to “failing”.

  FIG. 16-S3-2: NEF # 2 refers to the VP management table No.2 of NEF # 2 in FIG. 14B, determines whether switching is possible from “line information” and “line state”, The information "protection line" "line status" failure is detected and switching to the protection line is impossible. As a result, the “line information” in the VP management table No. 2 of NEF # 2 in FIG. 14B changes to “unusable”.

  16-S3-3: For NEF # 2 to OpS4, search request data (P-2-B = P-U-B) in the command part in the parameter part of the interface frame format between OpS and NEF in FIG. And a search request for whether there is an empty line in the same route line as the protection line is transmitted.

  FIG. 16-S3-4: OpS4 receives search request data (P-2-B = P-U-B) from NEF # 2 to determine whether there is an empty line in the same route line as the protection line.

  16-S3-5: OpS4 refers to VP management table No. 2 of OpS4 in FIG. 14C from the received search request data (P-2-B = P-U-B), and displays “OpS. The transmission apparatus connected from the “managed line” recognizes NEF # 1 = NEF # 2. OpS4 retrieves the “line information” free line of NEF # 1 = NEF # 2 from the VP management table of OpS4 in FIG. 14C, and transmits the transmission path PATH-C (NEF # 1 ( PU-A = P-1-C) = NEF # 2 (P-2-C = PU-B) is detected.

  FIG. 16-S3-6: For OpS4 to NEF # 2, search result data (P-2-C = PUB) in the command part in the parameter part of the interface frame format between OpS and NEF in FIG. Is sent, and a search result is sent out as to whether there is an empty line in the same route line as the protection line.

  FIG. 16-S3-7: NEF # 2 is a search result from OpS4, and is a free line (P-2-C = PU−) in the same path line as the protection line in the interface frame format between OpS and NEF in FIG. B) is received.

  FIG. 16-S3-8: NEF # 2 refers to the VP management table No. 3 of NEF # 2 in FIG. 14B, detects that “line information” is in failure, and goes to the same route line as the protection line. Switching is impossible. “Line information” in the VP management table No. 3 of NEF # 2 in FIG. 14B changes to “unusable”.

  FIG. 16-S3-9: For NEF # 2 to OpS4, the search request data (“connection destination transmission device” NEF #) in the command part in the parameter part of the interface frame format between OpS and NEF in FIG. 1 and (P-2-B = P-U-B)) are assigned and transmitted.

  FIG. 16-S3-10: OpS4 receives search request data ("connection destination transmission apparatus" NEF # 1 and (P-2-B = P-U-B)) for switching the other path from NEF # 2.

  FIG. 16-S3-11: OpS4 determines the other path switching search request data (“connection destination transmission device” NEF # 1 and P-2-B = PUB) from OpS4 in FIG. 14C. VP management table No. 2 is referred to, and the transmission apparatus connected from the “line managed by OpS” recognizes NEF # 1 = NEF # 2.

  OpS4 searches the VP management table of OpS4 in FIG. 14C for “line information” free line on the other path of NEF # 1 = NEF # 2, and transmits the transmission path PATH-D (NEF) of VP management table No.4. # 1 (PUA = P-1-D) = NEF3 (# 3) (P-3-D)) and No. 5 transmission path PATH-E (NEF3 (# 3) (P-3) -E) = NEF # 2 (P-2-E = PUB)).

  FIG. 16-S3-12: For OpS4 to NEF # 1, the other path switching setting data (PUA = P-1-) is added to the command part in the parameter part of the interface frame format between OpS and NEF of FIG. D) is added and sent out.

  FIG. 16-S3-13: NEF # 1 receives the other-path switching setting data (P-U-A = P-1-D) from OpS4, and changes the working line to the transmission path PATH-A by its own VPMDX control. The switching setting process is executed from (PU-A = P-1-A) to the transmission path PATH-D (PU-A = P-1-D) of the other path. “Line information” in the VP management table No. 1 of NEF # 1 in FIG. 14A changes to “unusable”, and “line state” changes to “failing”. “Line information” in the VP management table No. 2 of NEF # 1 is set to “Unusable”, “Line information” in the VP management table No. 3 is set to “Unusable”, "Changes to" working line ".

  FIG. 16-S3-14: For NEF # 1 to OpS4, processing execution result data (PUA = PUA) in the command part in the parameter part of the interface frame format between OpS and NEF in FIG. P-1-D) is assigned and transmitted.

  16-S3-15: For OpS4 to NEF # 3, line setting data (P-3-D = P-3-E) in the command part in the parameter part of the interface frame format between OpS and NEF in FIG. Is sent out.

  FIG. 16-S3-16: NEF3 (# 3) receives line setting data (P-3-D = P-3-E) from OpS4, and P-3-D = P-3-E line setting. Execute the process. Therefore, a VP management table is created in NEF3 (# 3) in FIG.

  FIG. 16-S3-17: Line setting execution result response data (P-3-D = P) in the command part in the parameter part of the interface frame format between OpS and NEF in FIG. 3 from NEF3 (# 3) to OpS4 P-3-E) is assigned and sent.

  FIG. 16-S3-18: For OpS4 and NEF # 2, in the command part in the parameter part of the interface frame format between OpS and NEF in FIG. B) is added, and the setting for switching to the transmission path PATH-E (P-2-E = PUB) is sent out.

  FIG. 16-S3-19: NEF # 2 receives the other path switching setting data (P-2-E = PUB) from OpS4, and changes the working line to the transmission path PATH-A by the VPMDX control of its own station. The switching setting process is executed from (P-2-A = PUB) to the transmission path PATH-E (P-2-E = PUB) of the other path. The “line information” in the VP management table No. 1 of the NEF # 2 in FIG. 14B changes to “unusable”, and the “line information” in the VP management table No. 4 changes to “working line” (FIG. 15). (B)).

  FIG. 16-S3-20: For NEF # 2 to OpS4, processing execution result data (P-2-E = P2-E =) in the command part in the parameter part of the interface frame format between OpS and NEF in FIG. P-U-B) is assigned and transmitted. In FIG. 14C, “Line information” in the VP management table No. 1 of OpS4 is set to “unusable”, “Line information” in VP management table No. 2 is set to “unusable”, and VP management table No. 3 “Line information” in “VP management table No. 4” changes to “Working line”, and “Line information” in VP management table No. 5 changes to “Working line”. As described above, the basic configuration diagram of FIG. 14 becomes the basic configuration diagram of FIG. 15 after the switching is completed.

  In the third embodiment, the processing is not stopped by switching to the protection line NG, but the connection destination transmission device information is added to the VP management table managed by NEF, and whether the other path can be switched is OpS4. To request. A process of searching for a pattern that can relieve the working line via the other path is added to OpS4. The other line setting thereafter uses an existing line / line setting process.

  As described above, when the assigned spare line is out of order, the active line can be relieved by searching for and assigning a spare spare line from another route. Furthermore, it is possible to realize high-speed restoration, and it is possible to improve the reliability of the communication line economically. As a result, transmission lines and VPs that are not allocated can be effectively used, and this is a significant contribution to the industry.

It is a figure which shows the example of a basic composition of ATM (Asynchronous Transfer Mode network). It is a sequence diagram in the prior art in which working lines and protection lines are set from OpS to NEF # 1 and NEF # 2. It is a figure which shows "the interface frame format between OpS-NEF." It is a figure which shows "VP-APS cell format." It is a figure which shows the aspect after switching when switching operation is performed in the form example shown in FIG. It is a figure explaining the structural example of OpS4, and the connection form of OpS4 by the control network 3, and several transmission apparatus NEF (# 1- # n). It is a figure which shows the structural example of NEF connected to OpS4 through the control network 3. FIG. It is a figure which shows the structural example (before VP switching) of the ATM network of the example of 1st Embodiment according to this invention, and the state of a VP management table. It is a figure which shows the structure of the ATM network after VP switching, and the state of a VP management table. It is an operation | movement sequence diagram of the 1st Embodiment in which switching is mainly performed by NEF. It is a figure which shows the structural example (before VP switching) of the ATM network of the 2nd Example according to this invention, and the state of a VP management table. It is a figure which shows the structure of the ATM network after VP switching, and the state of a VP management table. It is an operation | movement sequence diagram of the 2nd Embodiment in which switching is mainly performed by NEF. It is a figure which shows the structural example (before VP switching) of the ATM network of the example of 3rd Embodiment according to this invention, and the state of a VP management table. It is a figure which shows the structure of the ATM network after VP switching, and the state of a VP management table. It is an operation | movement sequence diagram of the 3rd Example which is switched by OpS main body.

Explanation of symbols

1, 2 Transmission equipment 3 Control network 4 Operation system

Claims (3)

A plurality of transmission devices constituting the transmission path;
The connected through a plurality of transmission devices to the control network, the monitoring control line that have the plurality of transmission devices, and has an operation system having a management table for managing the virtual path,
Preliminary lines have already been allocated to the working lines of the ATM network virtual path,
The working line connecting the local station transmission device and the opposite station transmission device when switching to the protection line, if the previously allocated spare channel of a failure, the operating system by referring to the management table, the said protection line enhanced virtual path switching method characterized by enabling rescue the working line by being assigned searching for idle spare channel of the same transmission path within a virtual path that connects the local station transmission apparatus the opposite station transmission device . A plurality of transmission devices constituting the transmission path;
The connected through a plurality of transmission devices to the control network, the monitoring control line that have the plurality of transmission devices, and has an operation system having a management table for managing the virtual path,
Preliminary lines have already been allocated to the working lines of the ATM network virtual path,
When switching the working line connecting the local station transmission apparatus and the opposite station transmission apparatus to a protection line, if the pre-assigned protection line fails, the operation system refers to the management table and is the same as the protection line. enhanced virtual path switching system characterized by an enabling rescue the working line by being assigned searching for idle spare channel with the end attribute of. In claim 2 ,
2. The extended virtual path switching system according to claim 1, wherein the idle backup line having the same termination attribute as the protection line is a line that bypasses a transmission apparatus different from the local station transmission apparatus and the opposite station transmission apparatus.

Images