JP2998635B2 - Alarm transfer method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an alarm transfer system for an ATM communication device, and more particularly to an alarm transfer system for transmitting a failure in a non-ATM transmission line of an ATM communication device connected to a non-ATM transmission line.

[0002]

2. Description of the Related Art In an ATM communication apparatus, when a transmission path failure occurs, a VPI (Virtual Path) of a connection destination of the transmission path failure occurs.
Id e ntifier) VP-AIS ( A to the number
An alarm indication signal is transmitted to notify a downstream device that a transmission line failure has occurred upstream.

[0003] However, the above-mentioned alarm transmission method is VP (Vir).
This is a method that is performed when a transmission path failure occurs in a section where the “Tual Path” is set, and cannot be applied to a transmission path failure that occurs in a section where a non-ATM signal is transmitted.

In the non-ATM signal, when focusing on one channel, data is written at a fixed position in the transmission frame, and the position of the fault alarm is fixedly determined by the type of the fault. In the signal failure alarm transfer method, an alarm pattern corresponding to the type of the failure is written in a corresponding position in a transmission frame to perform an alarm transfer to a downstream device.

[0005] Therefore, when a transmission path failure occurs at the boundary where the non-ATM transmission is converted to the ATM transmission, it is necessary to transfer the non-ATM signal through the ATM transmission path. Can not.

[0006]

SUMMARY OF THE INVENTION A non-ATM signal is transmitted to an ATM.
As long as the data is transmitted on the transmission line, it is necessary to write the alarm information in the ATM cell and transfer it for the transmission line failure occurring in the non-ATM section.

In normal operation, when information to be written in one ATM cell is stored in the buffer memory, an ATM cell in which the information is written is generated. However, for example, when the clock pulse of the non-ATM signal disappears, the information of the non-ATM signal cannot be written in the memory, so that information for one cell is not stored, and a trigger signal for generating an ATM cell cannot be obtained. For this reason, no ATM cell is generated, and the alarm information cannot be transferred using this cell. Therefore, even when such a transmission path failure occurs, it is necessary to continuously generate the ATM cells, and it is necessary to generate the ATM cells at the same interval even when shifting from the normal state to the failure state. .

The reason why the interval between ATM cells must be constant is as follows. In ATM networks, CDV
(Cell Delay Variation), which has a property of causing a cell arrival delay fluctuation.
This is because even if the sending side sends out ATM cells at regular intervals,
This means that the ATM cells do not always arrive at a fixed interval on the receiving side. For this reason, when transmitting a synchronization signal such as an STM signal through the ATM network, the AT carrying the synchronization signal
The circuit for restoring the M cell to the original synchronizing signal is provided with a buffer memory for absorbing CDV. At the start of operation, a certain amount of data is stored in this buffer memory in advance, and then data reading is started. By doing this,
Even if there is a CDV in the arriving cell after the start of reading, the amount of data stored in the buffer memory fluctuates before and after the first amount of storage. If the generation interval of the ATM cells is changed in the transmission-side cell forming unit, the fluctuation on the receiving side is larger than the CDV generated on the ATM network, and may exceed the allowable range of the buffer memory. Even if it does not exceed the allowable range, the amount of data stored in the buffer memory in the steady state will fluctuate around a value different from the amount of storage stored at the start of operation, and the CDV generated in the ATM network will not change. The function of absorbing the water is no longer guaranteed.

The present invention has been made under such a background. The first invention corresponding to the case where the number of alarm patterns to be used is one or more, and the one to be used when the number of alarm patterns to be used is one.
Although the second invention corresponding to the first case is included, the purpose of the invention in any case is to reduce the amount of data stored in the buffer memory of the decelerating unit on the receiving side without affecting the celling unit on the transmitting side. The present invention is to provide an alarm transfer method for transferring an alarm of a failure occurring in a non-ATM transmission line, which is input to a non-ATM transmission line, through the ATM transmission line.

[0010]

According to a first aspect of the present invention, there is provided an alarm transfer system comprising: a transmission line failure detection unit for detecting a transmission line failure of a non-ATM transmission line; and an alarm pattern for generating an alarm pattern corresponding to the transmission line failure. The generation means and an ATM cell which contains no valid information other than a cell header is stored in a buffer memory of a transmission-side cell-forming unit of the ATM communication apparatus with a period in which data for one cell is stored as a cycle. A generated in synchronization with the timing at which the data for the cell is read
The TM cell generating means writes data read from the buffer memory into a first predetermined area of the payload of the ATM cell when the transmission path failure is not normally detected, and detects the transmission path failure when the transmission path failure is detected. Data / alarm selection writing means for writing an alarm pattern in the area, and when a transmission path failure is detected, the second
AT with a predetermined alarm pattern written in a predetermined area of
M cells are transmitted.

On the receiving side, an alarm pattern detecting means for detecting an alarm pattern written in the second predetermined area, and a failure alarm signal restored to a non-ATM signal are transmitted to the non-ATM transmission line when a transmission path failure occurs. To an alarm pattern that conveys
There is an alarm pattern rewriting means for sending out to a non-ATM transmission line connected to the ATM communication device.

The second predetermined area may be made coincident with the first predetermined area in which data is normally written in a normal state by using an alarm pattern for notifying the occurrence of a transmission path failure in a non-ATM transmission path as the failure alarm pattern.

In the alarm transfer system according to a second aspect of the present invention, a predetermined fault alarm pattern is included in a predetermined area of a payload other than a cell header, in addition to a cell header. ATM cell generation for generating an ATM cell with a period in which data of one cell is accumulated in a buffer memory of a cell-forming unit on the transmission side of the ATM communication apparatus and in synchronization with a timing at which data of one cell is read. Means for overwriting data read from the buffer memory in a predetermined area of the ATM cell payload in a normal area where no transmission path failure is detected with an alarm pattern,
A transfer data writing unit for stopping overwriting of the data when a transmission path failure is detected; and when a transmission path failure is detected, an ATM cell in which a predetermined alarm pattern is written in a predetermined area of the payload is transmitted. .

[0014] As the alarm pattern, an alarm pattern for transmitting a transmission path failure on a non-ATM transmission path may be used.

[0015]

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 shows an AT connected to a non-ATM transmission line.
FIG. 2 is an example of a block diagram showing an embodiment of the alarm transfer system of the first invention in the M communication device. FIG. 1 shows a main part on the transmitting side of the above-mentioned alarm transfer system, which includes a memory 101, a transmission line failure detection unit 102, an alarm pattern generation unit 103, an ATM
The cell path is described with the cell generator 104, the transfer information selector 105, and the transfer information writer 106.

Here, the ATM cell generating section 104 is self-propelled so as to generate an ATM cell in which only a cell header is written, at a fixed period, that is, a period in which data of one cell is stored in the memory 101. I have.

When the transmission path failure is not detected by the transmission path failure detection unit 102, that is, when the transmission path failure is normal, the data (S101) input as the non-ATM signal is temporarily stored in the memory 1
01 is written. When data for one cell to be written to one ATM cell is stored in the memory 101, the ATM cell generator 104 reads the data (S103) from the memory 101 in synchronization with the timing of the next ATM cell to be generated. (A memory of one cell is stored in the memory 101, and an ATM cell is generated at the timing of starting reading.) Since the transmission path failure has not been detected in the transfer information selecting unit 105, the transfer information selecting unit 105 reads the cell from the memory 101. Data (S103) is selected, and the transfer information selecting unit 10
The transfer information (S106) selected in step 5, ie, the data, is written in the transfer information writing unit 106 into a first predetermined area in the payload of the ATM cell (S107) generated by the ATM cell generating unit 104, and the data ( 10
The ATM cell (S108) in which 3) has been written is transferred.

Next, when a transmission path failure is detected by the transmission path failure detecting section 102, for example, when the input non-ATM signal clock pulse (S102) is no longer input, the transmission path failure detecting section 102 It is detected as a transmission path failure, and a failure occurrence notification (S104) is made. When the alarm pattern generation unit 103 receives the failure occurrence notification (S104), it outputs an alarm pattern (S105) according to the content of the failure. The transfer information selection unit 105 selects an alarm pattern (S105) as the transfer information (S106) instead of the data (S103). The transfer information writing unit 106 sets an alarm pattern (S10) in a second predetermined area in the payload of the ATM cell (S107) generated by the ATM cell generation unit 104.
5) is written, and the ATM cell (S108) in which the alarm pattern (105) is written is transferred.

Before the non-ATM signal is restored from the ATM cell by the decellularizing unit, the ATM cell transferred to the receiving side device monitors a second predetermined area where an alarm pattern is to be written, and the alarm pattern is determined. If it has been written, the restored non-ATM signal (actually, normal data is not written due to the effect of the transmission path failure) is transmitted to the downstream device when a transmission path failure occurs in the conventional non-ATM network. Rewrite to the alarm pattern transferred to.

Next, how information is written in the ATM cell will be described with reference to FIG. The ATM cell (S107) generated by the ATM cell generator 104 is shown in FIG.
As shown in (a), no valid information is written except for the header portion. In a normal state before the detection of the transmission path failure, the transfer information selecting unit 105 selects the data (S103) from the memory 101, and the data (S103) is used as the transfer information (S106) in the first predetermined area of the ATM cell (S107). Is written as shown in FIG. 2B. When a transmission path failure is detected, the alarm pattern (S105) is selected by the transfer information selection unit 105 and the ATM cell (S10
The data is written in the second predetermined area of 7), and becomes as shown in FIG.

In the above example, the area where the transfer data is written in the normal state is placed at the beginning of the payload, and the area where the alarm pattern (S105) to be transferred when the transmission path failure is detected is placed at the end of the payload. In practice, there is no problem in using any area in the payload.
However, it is necessary to allocate different areas between the normal data area, ie, the first predetermined area, and the alarm pattern area, ie, the second predetermined area. That is, when the pattern of the data at the time of normality matches the alarm pattern, if each uses the same area, on the detecting side, that is, on the receiving side with the decellularization circuit for restoring the non-ATM signal from the ATM cell,
This is because it cannot be determined whether normal data has been sent or a failure has been notified.

Here, if the alarm pattern generated by the alarm pattern generator 103 is the same as the alarm pattern used to notify a downstream device of the occurrence of a failure when a transmission line failure occurs in a conventional non-ATM network. The following effects can be considered.
In the above example, the normal data area and the alarm pattern area when the transmission path failure is detected use different areas, but in this example, the same area can be used. Therefore,
For example, even when a transmission line failure is detected, the alarm pattern area shown in FIG.
If the data area (first predetermined area) shown in (b) is used, the transferred ATM cell (S108) is as shown in FIG. 2 (d).

In this example as well, an arbitrary area in the payload can be used as an area for writing information. However, the normal data area and the alarm pattern area can be matched,
When such an ATM cell format is used, an alarm pattern detection circuit provided before the non-ATM cell restoration circuit of the receiving apparatus, and a circuit for rewriting the non-ATM signal restored at the time of detection of the alarm pattern into an alarm transfer pattern in the non-ATM network. You do not need to have The reason is that the data is written in the normal state, so if it is restored as it is, the original non-ATM
This is because if the signal is reproduced and the received ATM cell is restored as it is even when the transmission line fails, the normal data portion has already been replaced with the alarm pattern. That is, there is no need to change the configuration of the receiving side of the ATM communication apparatus at all.

FIG. 3 is an example of a block diagram showing an embodiment of the alarm transfer system according to the second invention, which includes a memory 301, a transmission path failure detection unit 302, an ATM cell generation unit 303, a transfer data writing unit 304, a signal Is shown.

The second aspect of the present invention corresponds to a case where a single type of alarm pattern is used to indicate a transmission path failure, for example, to indicate only whether or not a transmission path failure has occurred.

In FIG. 3, the ATM cell generator 303
Regardless of whether or not the transmission path failure is detected by the transmission path failure detection unit 302, an ATM cell (S305) in which an alarm pattern is written in a predetermined area in the payload is always generated. Correct information is written in the header of the ATM cell generated at this time. In addition, data of one cell is stored in the memory 301 at the generation interval of the ATM cell.
It is self-propelled so as to generate ATM cells at the same interval as time .

When the transmission path failure is not detected, that is, when the transmission path is normal, the transfer data writing unit 304 reads the ATM cell (S305) generated by the ATM cell generation unit 303 from the memory 301 to the area where the alarm pattern is written. An ATM cell (S306) overwriting the output data (S303) is output. That is, in the ATM cell format, the data area at the time of normal operation matches the alarm pattern area at the time of failure.

When the transmission path failure detecting section 302 detects a transmission path failure, the failure notification (S304) is used for switching control of the transfer data writing section 304. When the transmission path failure occurs, the output ATM of the transfer data writing section 304 is output. As the cell (S306), the ATM cell (S305) to which the alarm pattern has been written, generated by the ATM cell generating unit 303, is output as it is.

An explanation will be added with reference to FIG.
The ATM cell (S30) generated from the cell generation unit 303
5) is as shown in FIG. 2D. When a transmission path failure is detected, the ATM cell (S
In step 306), the ATM cell (S305) generated by the ATM cell generator is output as it is, and the state shown in FIG.
When the transmission path failure is not detected, the transfer data writing unit 304 overwrites the alarm pattern area with the data from the memory 301, as shown in FIG. 2B.

As described above, since the data area at the time of normal operation and the alarm pattern area at the time of transmission path failure coincide with each other, an alarm pattern for notifying a downstream apparatus of a transmission path failure in a non-ATM network is used. The same alarm pattern can be used, so that no changes need to be made to the configuration of the receiving side of the ATM communication device.

[0032]

As described above, according to the present invention, a failure pattern written in an ATM cell, which is generated at a fixed period and at a fixed timing, from a normal time during data transfer to a time when a failure occurs, is transferred. , The non-AT on the receiving side
The non-AT to which the transmitting-side cell unit is connected without affecting the data storage amount of the buffer memory of the M signal restoration circuit
There is an effect that an alarm of a fault that has occurred in the M transmission path can be transferred through the ATM transmission path. It does not affect the amount of data stored in the buffer memory. Therefore, when the buffer memory underflows or overflows, there is no need to worry about transmission line failure on the transmission side, and it simply occurs in the ATM network. It can be determined that the CDV has become larger than the specified value (the value estimated at the time of design). Therefore, maintainability (reliability of maintenance data) is improved.

[Brief description of the drawings]

FIG. 1 is an example of a block diagram showing an embodiment of an alarm transfer system according to the first invention.

FIG. 2 shows examples of ATM cell formats (a), (b),
It is a figure showing (c) and (d).

FIG. 3 is an example of a block diagram showing an embodiment of an alarm transfer system according to the second invention.

[Explanation of symbols]

 101 memory 102 transmission line failure detection unit 103 alarm pattern generation unit 104 ATM cell generation unit 105 transfer information selection unit 106 transfer information writing unit S101 input data S102 input clock pulse S103 transfer data S104 failure information S105 alarm pattern S106 transfer information S107 header only Correctly attached ATM cell S108 ATM cell 301 Memory 302 Transmission path failure detection unit 303 ATM cell generation unit 304 Transfer data writing unit S301 Input data S302 Input clock pulse non-ATM signal S303 Transfer data S304 Failure information S305 Alarm pattern written ATM cell S306 ATM cell

Claims (2)

(57) [Claims] 1. An alarm transfer system for an ATM communication device connected to a non-ATM transmission line, comprising: a transmission line failure detecting means for detecting a transmission line failure of the non-ATM transmission line; and an alarm pattern corresponding to the transmission line failure. An alarm pattern generating means for generating, and an ATM cell containing no valid information other than a cell header, wherein a period of time for storing one cell of data in a buffer memory of a transmitting-side cell-forming unit of the ATM communication device is defined as a cycle;
An ATM cell generating means for constantly generating data in synchronism with the timing at which the stored data of one cell is read out;
When data read from the buffer memory is written in a first predetermined area of a cell payload and the transmission path failure is detected, the data is stored in a second predetermined area different from the first predetermined area of the payload. Data / alarm selection writing means for writing an alarm pattern, wherein when the transmission path failure is detected, the second
ATM in which the alarm pattern is written in a predetermined area of
An alarm transfer method, wherein cells are transmitted. 2. An alarm transfer method for an ATM communication device connected to a non-ATM transmission line, comprising: a transmission line failure detection means for detecting a transmission line failure of the non-ATM transmission line; An ATM cell containing a predetermined failure alarm pattern is read out at a period of time in which data of one cell is accumulated in a buffer memory of a transmission side cell unit of the ATM communication device, and the data of one cell is read out. ATM cell generating means for constantly generating data in synchronism with the timing at which the data is read out. In a predetermined area of the payload of the ATM cell, when the transmission path failure is not detected, the data read from the buffer memory is overwritten on the alarm pattern. A transfer data writing unit for stopping overwriting of the data when the transmission path failure is detected, Once detected, ATM said predetermined alarm pattern in a predetermined area of the payload is written
An alarm transfer method, wherein cells are transmitted.