JP2003298474A - Line identification method and system thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a line identification method and system thereof for distinguishing active lines from a standby line and accurately detecting an error even when the standby line is connected to an active system port by mistake. <P>SOLUTION: A code of an APS (Automatic Protection Switch) mode representing types of lines is defined and assigned to the active lines 1 to 3 and the standby line 4, a storage section 44c (64c) of the APS mode stores a code number in the APS mode, a comparison section 44b (64b) compares the stored code number with a code number of a code of a mode indicated by K2 bytes in a reply frame returned in response to a request frame, and a fault discrimination section 44d (64d) discriminates it to be a connection fault of the line when both the code numbers are non-coincident and detects a connection error. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a line identification method and system for identifying a working line and a protection line connected between a terminal station and a relay station or between relay stations.

[0002]

2. Description of the Related Art In a conventional system, for example, SONET
(Synchronous Optical Network
ork) / SDH (Synchronous Digi)
Tal Hierachy) supported linear AP
S (Automatic Protection Sw)
It) is used. This linear APS
Prepare one spare line in advance for a plurality of working lines connected between the terminal station and the relay station or between the relay stations. When a failure is detected in the working line due to disconnection of the line, for example, Some have tried to maintain the transmission quality of transmitted data by switching the line to the protection line.

In this system, for example, as shown in the system configuration diagram of FIG. 8, one working line 1 to 3 is connected to each channel a to c, and the channels a to c are common. A backup line 4 is provided so that it can be connected. Line switching is based on SONET standard GR-253
-This is performed in the line layer defined by CORE (Issue 3) or the like, and the transmission side station 10 is provided with switches 11 to 13 so that a working line and a protection line can be simultaneously selected and connected to one channel. Has been. Also,
In the station 20 on the receiving side, switches 21 to 23 are provided so that either one working line or protection line can be selected and connected to one channel. In this conventional example, a transmission system for data transmission from the station 10 to the station 20 is shown, but bidirectional data transmission is performed between the stations 10 and 20 and is not shown in FIG. However, there is a transmission system for data transmission from the station 20 to the station 10.

The protocol for switching the line is the frame transmitted to the protection line 4 (see FIG. 9).
And K1 provided in the area of the line overhead of
It uses 2 bytes. This transmission frame is
It is composed of a section overhead of the lower layer, a path overhead of the upper layer, and a payload which is a field for transmitting actual data. As shown in FIGS. 10 and 11, the K1 and K2 bytes are 8-bit management data. Of these, the K1 byte in FIG. 10 is
This is data for a switching request, and the K2 byte in FIG. 11 is data for a switching response.

The K1 byte is composed of a switching request code (request) and a channel number corresponding to a faulty line when a fault occurs. The K2 byte is an Archit indicating the channel number of the data signal transmitted to the protection line and the switch switching mode.
image and APS modes.

In such a configuration, the working lines 1 to 3
When a failure occurs in one of the channels, for example, the working line 3, the receiving side station 20 uses this K1 byte to detect a failure due to, for example, the presence / absence of a data signal reception or a bit error of the data signal. The data signal of c is the protection line 4
So as to be transmitted to the transmission side, a transmission system (not shown) transmits a request frame to the transmitting station 10 via the protection line 4 to make a line switching request.

In response to this request, the transmitting side station 10 turns on the switch 13 of the channel c to connect it to the protection line 4, and uses this K2 byte to send a response frame indicating that the connection has been completed. Receiving station 2 via protection line 4
Send to 0.

When the receiving side station 20 receives the frame for replying that the connection to the protection line 4 by the transmission side station 10 is completed, the receiving side station 20 sets the switch 23 of the channel c to the protection line 4 side (solid line part in FIG. 8). And the data signal of channel c is transmitted to the protection line 4. As described above, in the conventional system, the protection line is used for the protocol processing of K1 and K2 bytes. Although K1 and K2 bytes are also present in the frame transmitted to the working line, GR-253-CORE (Issue3 5.3.
In 5.5footnote15), these K1 and K2 bytes were undefined.

[0009]

However, in the above-mentioned conventional example, the distance between the station 10 and the station 20 is long, and the same connector is used for connecting each line 1 to 4 to the station. ing. Therefore, for example, as shown in FIG. 12, the protection line 4 is added to the port in which the working line 1 and the protection line 4 are misconnected, for example, the working port 20a of the station 20 to which the working line 1 should be connected, The working line 1 may be connected to the standby system port 20d of the station 20 to which 4 should be connected.

In this way, if the wrong port is connected to the line, the switching request from the standby port 20d of the station 20 will be received by the active port 10a of the station 10. Therefore, in the working system using the working line, K1 and K
If 2 bytes are not defined, this switching request may be ignored, and there is a problem that normal switching control of the line cannot be performed.

When the K1 and K2 bytes are defined in the active system, the same AP from the active port to the standby port is used.
There is a problem that S information may be transmitted, and in such a case, the working port and the protection port cannot be distinguished from each other, so that an error in connection cannot be detected.

The present invention has been made in view of the above problems, and makes it possible to distinguish between a working line and a protection line, and even if the protection line is erroneously connected to a working port, the error can be accurately detected. An object of the present invention is to provide a line identification method and its system.

[0013]

In order to achieve the above object, according to the present invention, a plurality of active data transmissions for bidirectional data transmission of a frame having a hierarchical header between a terminal station and a relay station or between relay stations. An assigning step of assigning a code indicating the APS mode to the working line and the protection line in a line identification method that includes a line and at least one protection line, performs line switching by a linear APS function, and identifies each of the lines; A first creating step of creating a request frame for judging the state of the line; a first sending step of sending the request frame to a partner station via each line; In response to the response, a second creating step of creating a frame for response based on the assigned code, and a frame for the response via each line. A second transmission step of transmitting,
There is provided a line identification method including a determination step of determining that a failure has occurred when the code in the received response frame and the assigned code are different.

According to the present invention, the APS mode code indicating the type is defined and assigned to the working line and the protection line, and the code in the response frame returned in response to the request frame is pre-assigned. If it does not correspond to the code, if it does not correspond, it is judged that the line connection is abnormal and a connection error is detected.

According to a second aspect of the present invention, in the above invention, the code in the response frame is a mode code forming the K2 byte in the line layer header.

According to the present invention, by writing the code numbers indicating the working line and the protection line in the mode that constitutes the K2 byte in the line layer header of the response frame,
Enables the distinction between working and protection lines.

According to a third aspect of the present invention, a plurality of working lines and at least one protection line for bidirectional data transmission of a frame having a hierarchical header are provided between the terminal station and the relay station or between the relay stations. , A line identification method for performing line switching by the linear APS function and for identifying each line, and an allocating step of allocating trace bytes to each of the working line and the protection line, and creating a frame including the allocated trace bytes And the transmission step of transmitting the frame to the partner station via each of the lines, comparing the frame byte in the captured frame with the trace byte set in the own line, and the frame bytes are And a determination step of determining that a failure has occurred when different.

According to the present invention, when trace bytes are assigned to the respective working lines and protection lines and a frame including the trace bytes is fetched from the partner station, the trace bytes and the trace bytes of the own line that have been previously assigned are allocated. If both trace bytes are different from each other, it is determined that the line connection is abnormal and a connection error is detected.

According to a fourth aspect of the present invention, in the above invention, the line identification method further includes an alarm step of outputting an alarm when it is determined that the fault has occurred.

According to the present invention, when the occurrence of a failure such as a connection error is detected, an alarm is output to notify the manager of the station.

According to a fifth aspect of the present invention, a plurality of working lines and at least one protection line connected between the terminal station and the relay station or between the relay stations are provided, and the terminal station and the relay station are:
Line switching control is performed by the line switching control unit using the linear APS function, and in the line identification system for identifying the line, a storage unit for storing a code indicating the APS mode in association with the working line and the protection line. A first creating means for creating a request frame for determining the state of the line, a first sending means for sending the request frame to a partner station via the respective lines, and the request According to the second generation means for generating a response frame including a code corresponding to a line for transmitting a frame, and a second transmission means for transmitting the response frame via each of the lines. Comparing means for comparing the code in the received response frame with the code corresponding to the line on which the response frame is received, and the comparison result of the code. Flip, the line identification system is provided which is characterized in that a determination means for determining failure.

According to the present invention, the APS mode code indicating the type is defined and assigned to the working line and the protection line, the code numbers are stored in the storage means, and are returned in response to the request frame. The code number in the response frame is compared with the stored code number. If the two code numbers are different, it is determined that the line connection is abnormal and a connection error is detected.

According to a sixth aspect of the present invention, in the above invention, the code in the response frame is a code constituting K2 bytes in the line layer header.

According to the present invention, the code number for specifying the working line and the protection line is written in the mode forming the K2 byte in the line layer header of the response frame to distinguish the working line and the protection line. To enable.

According to a seventh aspect of the present invention, a plurality of working lines and at least one protection line connected between the terminal station and the relay station or between the relay stations are provided, and the terminal station and the relay station are:
The line switching control unit using the linear APS function controls the line switching, and in the line identification system for identifying the line, a storage unit for storing trace bytes respectively corresponding to the working line and the protection line, and the trace. Comparing a creating means for creating a frame including bytes, a sending means for sending the frame to the partner station through each of the lines, and a trace byte in the captured frame and a trace byte set in the own line. It is characterized by comprising a comparing means and a judging means for judging the occurrence of a failure based on the comparison result of the trace bytes.

According to the present invention, a trace byte is assigned to each of the working line and the protection line, and the trace byte is stored in the storage means. When a frame including the trace byte is taken in, the trace byte and the trace byte are stored in advance. Compare with the trace byte of the own line that you made,
If both trace bytes are different, it is judged that the line connection is abnormal and a connection error is detected.

According to an eighth aspect of the present invention, in the above invention, the line identification system further comprises alarm means for outputting an alarm when it is determined that the fault has occurred.

According to the present invention, when the judgment means detects the occurrence of a failure such as a connection error, the alarm means outputs an alarm to notify the manager of the station.

[0029]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the line identification method and system according to the present invention will be described below with reference to the accompanying drawings.

(Embodiment 1) FIG. 1 is a configuration diagram showing a configuration of a line identification system according to the present invention. In the figure, in this system, as in the conventional example, each channel a
.. to c, one working line 1 to 3 is connected, and a common protection line 4 is provided so as to be connectable to each channel a to c.

The working lines 1 to 3 are provided with two lines 1a, 1b, 2a, 2b, 3a and 3 so that bidirectional transmission is possible.
b, 4a, 4b, respectively, which are connected between the terminal station and the relay station or between the relay stations. Note that the system of FIG. 1 shows the case between the relay station 30 on the upstream side and the relay station 50 on the downstream side, for example, from the relay station 30 to the relay station 5.
A frame is transmitted to 0 via the downstream working lines 1a, 2a, 3a, and a frame is transmitted from the relay station 50 to the relay station 30 via the upstream working lines 1b, 2b, 3b. To do. Also in the backup line 4, from the relay station 30 to the relay station 50, via the downstream backup line 4a,
It is assumed that each frame is transmitted from the relay station 50 to the relay station 30 via the upstream protection line 4b.

The relay station 30 transmits and receives frames to and from the relay station 50 via the lines 1 to 4, and includes transmitters 31a, 32a,
33a, 34a and receivers 31b, 32b, 33b,
34b, transmitters 35a, 36a, 37a for transmitting and receiving frames to and from an upstream station (not shown) and receiver 35
b, 36b, 37b and switches 38 to 4 for bridge
0, line switching switches 41 to 43, and a control circuit 44 that controls the operation of these devices and switches.

One end of each of the bridge switches 38 to 40 is a transmitter 31a, 32a, 33a and a receiver 35b, 3.
6b and 37b, and the other end is the transmitter 3
4a, the working line and the protection line are simultaneously selected and connected to one channel in the ON state. The line switching switches 41 to 43 are provided in the transmitter 35.
a, 36a, 37a and the receivers 31b, 32b, 33b are provided on the line, and by switching the receivers 31b, 32b, 33b and the receiver 34b, one working line for one channel or One of the protection lines is selected and connected.

The relay station 50 includes transmitters 51a, 52a, which transmit and receive frames to and from the relay station 30 via the lines 1 to 4.
53a, 54a and receivers 51b, 52b, 53b,
54b, transmitters 55a, 56a, 57a and a receiver 55 for transmitting / receiving frames to / from a downstream station (not shown).
b, 56b, 57b and switches 58-6 for switching lines
0, a bridge switch 61 to 63, and a control circuit 64 that controls the operation of these devices and switches.

The line changeover switches 58-60 include transmitters 55a, 56a, 57a and receivers 51b, 52b, 53.
receivers 51b, 52b, 53 provided on the line between b
By switching between b and the receiver 54b, either one working line or one protection line is selected and connected to one channel. The bridge switches 61 to 63 have one end connected to the line between the transmitters 51a, 52a, 53a and the receivers 55b, 56b, 57b, and the other end connected to the transmitter 54a. A working line and a protection line are simultaneously selected and connected to the channel.

The protocol for switching the line is
The K1 and K2 bytes provided in the field of the line overhead of the frame (see FIG. 9) transmitted to the working lines 1 to 3 and the protection line 4 are used. This K1
The K2 byte and the K2 byte are management data configured as shown in FIGS. In this example, K2
A code indicating the working line and the protection line is assigned to the APS mode in the byte.

As shown in the block diagram of FIG. 2, the control circuit 44 takes in a management data from each of the receivers 31b, 32b, 33b and 34b and a data input section 44a which takes in a K2 byte APS mode and pre-allocates it. Comparing section 44b for comparing with the assigned code number, and storage section 44c for storing the code numbers assigned to the working line and the protection line
And a failure determination unit 44d for determining the occurrence of failure, K1,
K1, K2 creation unit 44e that creates K2, alarm generation unit 44f that generates an alarm, and switches 38 to 4
The switch switching control unit 44g for controlling the operation of No. 3 of FIG.

The control circuit 64 similarly receives the receivers 51b,
A data input unit 64a for fetching management data from 52b, 53b, 54b, a comparison unit 64b, and a storage unit 64c.
And a failure determination unit 64d, a K1 and K2 creation unit 64e,
It is composed of an alarm generation unit 64f and a switch switching control unit 64g.

The storage units 44c and 64c store, for example, a code number indicating the APS mode of "000" assigned to the working line and "00" assigned to the protection line.
Data of predetermined APS mode numbers other than 0, “111” and “110” and data of code numbers “111” and “110” are stored.
"1" and "110" indicate the alarm form of the line.

The comparators 44b and 64b take in the K2 byte APS mode of the signals input from the receivers 31b to 34b and 51b to 54b in the own station, and the storage 44
c and 64c are compared with code numbers stored in advance. That is, when the K2 byte APS mode is input from the data input units 44a and 64a, the comparing units 44b and 64b determine whether the mode code number in the K2 byte is "000" when the input destination is the active port. If the input destination is the standby port, whether the code number of this mode is the predetermined APS mode number or not is stored in the storage unit 44.
The comparison result is compared with the code numbers of c and 64c, and the comparison result is output to the failure determination units 44d and 64d.

The fault decision units 44d and 64d monitor the signals input from the receivers 31b to 34b and 51b to 54b in the local station, and detect the fault occurrence in each line based on the presence or absence thereof or bit error. There is. Further, the failure determination units 44d and 64d are configured to input the input signal (frame).
The K1 and K2 bytes, which are the management data, are monitored. When a failure is detected by these monitoring, the failure determination units 44d and 64d cause the alarm generation unit 44 to operate.
Instructs f and 64f to generate an alarm.

That is, the failure judgment units 44d and 64d are
When the K1 byte of the line overhead is input, the K2 byte corresponding to the request information is created,
An instruction is given to the K1, K2 creating units 44e and 64e.
In this embodiment, when the K1 byte indicating the normal state of the line is input from the partner station for each line in the normal state, for example, the APS for the input from the working port.
Control is made so that a response frame having a K2 byte of mode "000" is transmitted from this active port to this partner station. For the input from the standby port, the APS mode is set to K of the above predetermined APS mode number.
A response frame having 2 bytes is controlled to be transmitted from this spare port to this partner station.

When the comparison results of the K2 byte APS mode are input from the comparison units 44b and 64b, the failure determination units 44d and 64d determine whether or not the comparison results match. Then, the failure determination unit 44d, 6
If the comparison result does not match, 4d indicates that a connection error has occurred in the working line connected to the working port or the protection line connected to the protection port that has acquired the mismatched APS mode. To judge.

The K1 and K2 creating sections 44e and 64e create K1 bytes at a predetermined cycle for each of the lines 1 to 4, and the transmitters 31a to 34a and 51a to 54a respectively set the active port and the standby port. To the other station next to
A request frame including 1 byte is transmitted. Also,
The K1 and K2 creating units 44e and 64e are connected to the failure determining unit 44.
Based on the instructions of d and 64d, K2 bytes, for example, in the case of output to the active port, "00" is set in the APS mode.
When the code number of "0" is output to the spare port, the predetermined APS mode number set above is created and output in the APS mode.

The switch switching control units 44g and 64g control the operation of the switches 38 to 43 and 58 to 63 based on the instructions from the failure determining units 44d and 64d. In this system, by controlling the operation of this switch, a protection line is selected in place of the working line in which a failure has occurred, and the data signal of each channel can be transmitted through this protection line.

In the above-mentioned control of the control circuits 44 and 64, the K1 byte may be output from the upstream station or the K1 byte may be output from the downstream station. , Or from both upstream and downstream stations, K1
You may output the byte.

Next, the connection error control operation of the control circuits 44 and 64 will be described with reference to the flow charts of FIGS. FIG. 3 is a flowchart for determining a connection error in the working line (working system port). In this embodiment, the case where the control circuit 64 creates the K1 byte will be described.

First, the failure determination unit 64d of the relay station 50
By a timer (not shown) provided inside, a fixed time t
It is determined whether or not 1 has elapsed (step 101), and each time this time t1 elapses, the K1 and K2 creating unit 64e outputs K.
Gives an instruction to create a request frame containing 1 byte.

Based on this instruction, the K1, K2 creating unit 64e creates a K1 byte having a request number for requesting switching and a channel number for switching, for each channel, and further creates this K1 byte. A request frame including the above is created, and each of the transmitters 51a to 54a
(Step 102). Each transmitter 51a-54
When the request frame is input, a transmits the request frame to each of the lines 1 to 4 via the active port and the standby port.

The failure judgment unit 44d of the relay station 30 is on standby for fetching the request frame including the K1 byte transmitted via the lines 1 to 4 (step 20).
1). Then, when the request frame is fetched from the receivers 31b to 34b via the active port and the standby port, the failure determination unit 44d causes the K1 and K2 creation unit 4 to operate.
4e is caused to create a response frame including K2 bytes.

The K1 and K2 creating unit 44e creates a K2 byte having a channel number for transmitting this frame and an APS mode for each channel having a K1 byte input, and outputs it to each of the transmitters 31a to 34a. (Step 202). When the response frame is input, each of the transmitters 31a to 34a transmits it to each of the lines 1 to 4 via the active port and the standby port.

The comparing section 64b of the relay station 50 is provided for each line 1 to
It waits for a response frame including the K2 byte transmitted via the protocol No. 4 (step 103). And
Receiver 51b via the active port and the standby port
When the response frame is fetched from 54b to 54b, the comparison unit 64b compares whether or not the K2 byte APS mode code number included in the response frame fetched through the active port is "000" ( Step 104).

Here, when the code number of this APS mode is "000", the failure judging section 64d judges that the working line is connected based on the comparison result (step 105), Determines whether or not it is the active port (step 106), and if it is not the active port, it causes the alarm generation unit 64f to report the occurrence of the failure (step 107), and returns to step 101 again to set time t1. Determine if it has passed. If the code number is other than "000", the comparison unit 64b compares the code number with "111" or "110" (step 108).

If the code number is "111" or "110", a predetermined alarm is generated (step 109). Otherwise,
It is considered that the protection line is connected to the working port (step 110). Next, it is judged whether or not it is the spare port (step 111). Here, when the self is the standby port, the switch switching control unit 64g is caused to execute the switch control processing based on this mode (step 112). If the port is not the standby port, the alarm generator 64f is caused to report the occurrence of a failure (step 1
13) Then, the process returns to step 101 again to judge whether or not the time t1 has elapsed.

When judging a connection error in this protection line (protection port), step 11 in FIG.
After 0, it is compared whether or not the APS mode of K2 is a predetermined APS mode number set in advance, and if this code number is the predetermined APS mode number, the failure determination unit 64d determines that it is a protection line. If this APS mode is not the predetermined APS mode number, "000", "1"
By determining whether it is 11 "or" 110 ", it is possible to determine whether the connected line is the working line.

Thus, in this embodiment, the APS mode code indicating the type is defined and assigned to the working line and the protection line, and the K2 APS mode code in the received response frame from each line is used. , If the pre-stored code is different, it is judged that the line connection is abnormal, so that the working line and the protection line can be easily distinguished, and even if the protection line is mistakenly connected to the working port, Errors can be detected accurately.

Further, in this embodiment, since the request frame and the response frame are transmitted at a constant cycle, it is possible to promptly detect the connection error of each line after a predetermined time has elapsed since the system was first started up.

In this embodiment, a code is assigned to each type of the working line and the protection line, so that the working line and the protection line can be easily distinguished. However, there are a plurality of working lines and the working lines are used. When a connection error occurs between lines, it is difficult to detect this connection error.

In view of the above, the present invention provides a line identification method and system for solving the above-mentioned problems and capable of accurately detecting a connection error in the following embodiments.

(Embodiment 2) This embodiment is different from Embodiment 1 in that the line switching protocol is
The point is to introduce a line trace byte. That is,
In this embodiment, an undefined field (for example, Data Com) provided in the field of the line overhead of the frame transmitted to the working lines 1 to 3 and the protection line 4 is used.
A line trace byte indicating each working line and protection line is assigned to the communication field).
This line trace byte defines and assigns a different value for each port to which the working line and the protection line are connected, for example.

Accordingly, in the block configuration of the control circuit shown in FIG. 5, the line trace bytes assigned to the active ports and the standby ports are stored in the storage units 44c and 64c. In this embodiment, for example, the working line 1
The line trace byte is "01" for the active port that connects the active line, the line trace byte is "02" for the active port that connects the active line 2, and the active port that connects the active line 3 , The line trace byte is defined as "03", and the line trace byte is defined as "00" for the spare port connecting the spare line 4.

The comparators 44b and 64b extract the line trace bytes stored in the field of the line overhead of the frame and compare the line trace bytes with the line trace bytes stored in advance. That is,
The comparing units 44b and 64b store the line trace byte corresponding to the port on which this frame is received in the storing unit 44c and
The line trace byte is read from 64c, the line trace byte is compared with the line trace byte on the received frame, and the comparison result is output to the failure determination units 44d and 64d.

The failure judgment units 44d and 64d are provided in the comparison unit 44.
When the comparison result of the line trace bytes is input from b and 64b, it is determined whether the comparison result is a match or a mismatch. Then, when the comparison result does not match, the failure determination units 44d and 64d determine that the working line connected to the working port or the protection line connected to the protection port that has captured the mismatched line trace byte. It is determined that there is a connection error in.

Further, the trace byte creation parts 44h and 64
h creates a trace byte at a predetermined cycle for each of the lines 1 to 4, and the transmitters 31a to 34a and 51a to 54a
A frame including this trace byte is transmitted to the adjacent partner station via each active port and standby port.

The above control of the control circuits 44 and 64 may be performed by outputting the trace byte from the upstream side station or by outputting the trace byte from the downstream side station. Alternatively, trace bytes may be output from both the upstream and downstream stations.

Next, the connection error control operation of the control circuits 44 and 64 will be described with reference to the flow charts of FIGS. 6 and 7. In this embodiment, the case where the control circuit 64 creates a line trace byte will be described.

FIG. 6 is a flow chart for explaining the operation of creating a line trace byte. In the figure,
The failure determination unit 64d of the relay station 50 determines whether or not a certain time t2 has passed by a timer (not shown) provided inside (step 301), and each time the time t2 passes, the trace byte creation unit 64h. Gives instructions to create a frame containing line trace bytes.

Based on this instruction, the trace byte creating section 64h creates a line trace byte for each of the lines 1 to 4, and also creates a frame including this line trace byte, and transmits each in time division, for example. Vessels 51a-5
4a (step 302). Each transmitter 51a-
54a, when this frame is input, transmits it to each of the lines 1 to 4 via the active port and the standby port.

FIG. 7 is a flow chart for judging a connection error in a line (port). In the figure,
The comparison unit 44b of the relay station 30 stands by for capturing the frame including the line trace bytes transmitted through the lines 1 to 4 (step 401). And
Receiver 31b via the active port and the standby port
When this frame is captured from ~ 34b, the comparison unit 6
4b compares, for example, whether or not the line trace byte included in the frame captured through the spare port is "00". Further, it is also compared whether the line trace bytes included in the frame captured through the working port to which the working lines 1 to 3 are connected are “01”, “02” and “03”. Then, the comparison result as to whether the captured line trace byte is different from the expected value is output to the failure determination unit 44d. (Step 402).

When the comparison results match, the failure judgment unit 44d performs the same signal processing as in the conventional case, for example, when the line overhead includes K1 bytes, processing such as creating K2 bytes for response. After doing (Step 4
03), wait for the capture of the next line trace byte.

Further, when the comparison result does not match, the failure judgment unit 44d is connected to the working line or the protection port connected to the working port which has fetched the line trace byte which becomes the mismatch. It is judged that a connection error has occurred in the protection line, and the alarm generation unit 64f
Alarm processing is performed to cause the failure to be reported (step 404). Then, the process returns to step 401 again to judge whether or not the line trace byte is fetched.

As described above, in this embodiment, the line trace bytes having different values are defined and assigned to the working line and the protection line, respectively, and the line trace bytes in the received frame from each line are stored in advance. If the line trace bytes are different, it is determined that the line connection is abnormal. Therefore, as in the first embodiment, the working line and the protection line can be easily distinguished from each other, and the working lines can be easily distinguished from each other. Even if the is connected to the wrong port, the error can be accurately detected.

Also in this embodiment, since the frame including the line trace bytes is transmitted at a constant cycle, as in the first embodiment, the connection error of each line can be quickly detected after a certain period of time from when the system first started up. Can be detected.

The present invention is not limited to these embodiments, and various modifications can be made without departing from the gist of the present invention.

[0075]

As described above, according to the present invention, a plurality of working lines for bidirectional data transmission of a frame having a hierarchical header between a terminal station and a relay station or between relay stations and at least one working line. Equipped with a backup line, linear APS
In the line identification method for performing line switching by the function and for identifying each line, an APS mode code indicating the type is defined and assigned to the working line and the protection line, and returned in response to the request frame. The APS mode in the response frame is set to the pre-assigned AP
If it does not match the S mode, it is judged that the line connection is abnormal, so it is possible to distinguish the working line and the protection line.
Even if the protection line is mistakenly connected to the working port, the error can be accurately detected.

Further, according to the present invention, a plurality of working lines and at least one protection line for bidirectional data transmission of a frame having a hierarchical header are provided between the terminal station and the relay station or between the relay stations, and the linear line is provided. In the line identification method for performing line switching by the APS function and for identifying each line, the trace bytes included in the frame received from the partner station are defined by assigning trace bytes to the working line and the protection line, respectively. If it does not match the pre-allocated trace byte of the own line, it is judged that the line connection is abnormal, so it is possible to distinguish between the working line and the protection line, and also to distinguish the working lines from each other. Even if you connect to the wrong port, you can detect the error accurately.

Further, according to the present invention, when the occurrence of a failure is detected, an alarm is reported, so that the administrator of the station can easily recognize the occurrence of the failure and correct the incorrect line connection. It is possible to quickly switch to.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing a configuration of a line identification system according to the present invention.

FIG. 2 is a block diagram showing a configuration of a first embodiment of the control circuit shown in FIG.

FIG. 3 is a flowchart for explaining a control operation of a line connection error by the control circuit shown in FIG.

FIG. 4 is likewise a flow chart for explaining the output operation of K2 by the control circuit.

5 is a block diagram showing a configuration of a second embodiment of the control circuit shown in FIG.

6 is a flowchart for explaining an operation of creating a line trace byte by the control circuit shown in FIG.

FIG. 7 is a flow chart for similarly determining a connection error by the control circuit.

FIG. 8 is a configuration diagram showing a schematic configuration of a conventional line identification system.

FIG. 9 is a configuration diagram showing a configuration of a frame transmitted by this line identification system.

10 is a configuration diagram showing a configuration of K1 in the line overhead shown in FIG.

FIG. 11 is also a configuration diagram showing the configuration of K2 in the line overhead.

FIG. 12 is a configuration diagram showing a schematic configuration of a line identification system when a line connection error occurs.

[Explanation of symbols]

1 to 3 working line 4 protection line 10, 20, 30, 50 station 10a to 10c, 20a to 20c working system port 10d, 20d protection system port 11 to 13, 21 to 23, 38 to 43, 58 to 63 switch 31a to 37a, 51a to 57a Transmitter 31b to 37b, 51b to 57b Receiver 44, 64 Control circuit 44a, 64a Data input unit 44b, 64b Comparing unit 44c, 64c Storage unit 44d, 64d Failure determination unit 44e, 64e K1, K2 creation Part 44f, 64f Alarm generator 44g, 64g Switch switching controller 44h, 64h Trace byte creation unit

Claims (8)

[Claims] 1. A line using a linear APS function, comprising a plurality of working lines and at least one protection line for bidirectional data transmission of a frame having a hierarchical header between a terminal station and a relay station or between relay stations. In the line identification method of performing switching and identifying each of the lines, an allocation step of assigning a code indicating the APS mode to the working line and the protection line, and creating a request frame for judging the state of the line And a first transmitting step of transmitting the request frame to the partner station via each of the lines, based on the assigned code at the time of responding to the request. A second creating step of creating a response frame; a second sending step of sending the reply frame via each of the lines; A line identifying method, comprising: a determining step of determining that a failure has occurred when the code in the frame and the assigned code are different. 2. The line identification method according to claim 1, wherein the code in the response frame comprises a code of a mode forming K2 bytes in a line layer header. 3. A line using a linear APS function, comprising a plurality of working lines and at least one protection line for bidirectional data transmission of a frame having a hierarchical header between a terminal station and a relay station or between relay stations. In the line identification method of switching and identifying each line, an allocating step of allocating a trace byte to each of the working line and the protection line, a creating step of creating a frame including the allocated trace byte, and The transmission step of transmitting the frame to the station via each of the lines is compared with the frame byte in the captured frame and the trace byte set in the local line, and if the frame bytes are different, a failure occurs. A line identification method comprising a determination step of determining. 4. The line identification method according to claim 1, further comprising an alarm step of outputting an alarm when it is determined that the failure has occurred. 5. A line switching control using a linear APS function, comprising a plurality of working lines and at least one protection line connected between the terminal station and the relay station or between the relay stations. In the line identification system for performing line switching control by means for identifying the line, storage means for storing a code indicating the APS mode corresponding to the working line and the protection line, and for determining the state of the line First creating means for creating a request frame, first transmitting means for sending the request frame to the partner station via each of the lines, and a line for sending a frame in response to the request Second creating means for creating a response frame including a corresponding code, and second transmitting means for sending the response frame via each of the lines, A comparison means for comparing the code in the response frame with a code corresponding to the line on which the response frame is received, and a determination means for determining a failure occurrence according to the comparison result of the code are provided. A line identification system characterized in that 6. The line identification system according to claim 5, wherein the code in the response frame comprises a code forming K2 bytes in a line layer header. 7. A line switching control using a linear APS function, comprising a plurality of working lines and at least one protection line connected between the terminal station and the relay station or between the relay stations. In the line identification system for performing line switching control by means for identifying the line, storage means for storing trace bytes respectively corresponding to the working line and the protection line, and creating means for creating a frame including the trace bytes A transmission means for transmitting the frame to the partner station via each of the lines, a comparison means for comparing the frame byte in the captured frame with a trace byte set in the own line, and a comparison of the frame byte A line identification system comprising: a determination unit that determines a failure occurrence based on a result. 8. The line identification system according to claim 5, further comprising an alarm unit that outputs an alarm when it is determined that the failure has occurred.