JPH06291778A - Cell flow supervisory equipment - Google Patents

Abstract

PURPOSE:To reduce a discrimination error in which a normal cell is regarded as a violation cell due to delay fluctuation. CONSTITUTION:An arithmetic operation circuit 15 and a register 16 count number of arrived cells. A discrimination circuit 17 discriminates whether or not a cell count X reaches a predetermined threshold level TH larger than an allowable cell number X in parallel with the cell count. When the count reaches the threshold level TH, a succeeding arriving cell is regardless as a violation cell and the count is stopped. The discrimination circuit 17 discriminates whether or not the cell count X exceeds the allowable cell number N. When exceeded, the arithmetic operation circuit 15 makes arithmetic operation of X-N and when not exceeded, the arithmetic operation circuit 15 makes arithmetic operation of X-X. The result of the arithmetic operation is latched to the register 16 as an initial value of the cell count X for a succeeding supervisory period.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cell flow rate monitoring device for monitoring whether or not cells are being transmitted according to a communication band declared value in an asynchronous transfer mode communication network.

[0002]

2. Description of the Related Art In recent years, in the field of information communication, a high-speed broadband service integrated digital communication network (hereinafter, referred to as "BIS
"DN") is being put to practical use.

In this BISDN, an asynchronous transfer mode (hereinafter referred to as "ATM") is adopted as a transfer mode. In this ATM communication, information is transferred and exchanged in fixed length packets called cells. In this case, the transfer destination of the cell is identified based on the destination address information given to each cell.

In such a configuration, unlike the time-divisional circuit switching, each terminal can send a cell anywhere in an empty slot. Therefore, a large number of cells may flow into the network at one time.

However, when such a situation occurs, network resources such as exchanges may be destroyed or it may not be possible to effectively utilize them.

Therefore, in the ATM communication, each terminal is requested to declare the communication band of the cell to be used in advance, and during communication, it is monitored at the entrance of the network whether or not each terminal is sending the cell according to the declared value. It is supposed to do. This monitoring of the cell flow rate is generally called policing.

Conventionally, several methods have been proposed as this policing method. A typical example is “Modeling and Performance Comparison of Po
licingMechanisms for ATM Networks ”, IEEE J. Areas C
ommun., VOL.9, NO.3, PP.325-334, (April 1991) "(hereinafter referred to as" Reference ") and a jumping window method (hereinafter referred to as" JW method ") and a moving window method. (Hereinafter referred to as “MW system”).

In these systems, a monitoring period having a time width defined by the declared value of the communication band is sequentially set at a predetermined timing, and the cell transmits in accordance with the declared value of the communication band for each monitoring period. It is designed to determine whether or not it has been received.

FIG. 2 is a timing chart showing how to set the monitoring period in the JW system. Similarly, FIG.
6 is a timing chart showing how to set a monitoring period in the MW system.

In these figures, Cm (m = 1, 2,
…) Are cells. In the figure, only cells sent from one terminal are shown as the cells Cm. Further, Pn (n = 1, 2, ...) Is a monitoring period. In addition,
The figure shows the case where the time width of the monitoring period Pn is set to 8 cell time length.

In the JW system, as shown in FIG. 2, the next monitoring period Pn is set each time each monitoring period Pn ends. On the other hand, in the MW system, as shown in FIG. 3, the monitoring period Pn is set for each cell slot.

Whether or not the cells are sent according to the declared value of the communication band is determined by counting the number of arriving cells for each monitoring period Pn in any method, and this cell count value is the declared value of the communication band. It is determined by determining whether or not the allowable value defined by

In this case, a cell whose cell count value does not exceed the permissible value is regarded as a cell according to the declared value (hereinafter referred to as "normal cell"). On the other hand, a cell whose cell count value exceeds the permissible value is regarded as a cell violating the declaration (hereinafter referred to as “violating cell”). The normal cell is directly subjected to the exchange process. On the other hand, the violating cell, if necessary,
Receive disposal such as disposal. As a result, the number of cells in each monitoring period Pn is limited to the allowable value.

FIG. 4 is a flow chart showing processing upon arrival of a cell in the JW system and the MW system. Similarly, FIG. 5 is a flowchart showing the processing at the end of the monitoring period.

When the cell arrives, as shown in FIG. 4, first, it is judged whether or not the cell count value X up to the previous cell arrival has reached the allowable value N (step S1).
1). In other words, it is determined whether or not the cell count value X up to the current cell arrival has exceeded the allowable value N.

If the cell count value X up to the previous cell arrival has not reached the allowable value N, the current arrival cell is regarded as a normal cell. Therefore, in this case, the cell count value is incremented by 1 (step S12).

On the other hand, if the cell count value X has reached the permissible value N, the current arrival cell is regarded as a violation cell.
Therefore, in this case, the violation processing of the arrival cell is performed (step S13). As a result, the arriving cell is subject to processing such as discarding.

When the above processing is completed, the cell waits, and when the next cell arrives, the above processing is performed again. Hereinafter, similarly, the above-described processing is repeated until the monitoring period Pn ends.

When the monitoring period Pn ends, the cell count value X is initialized as shown in FIG. 5 (step S).
21). When this process ends, the next monitoring period Pn is set, and the process as described in FIG. 4 is executed again.

In FIG. 5, X0 is X in the JW system and 1 in the MW system. Therefore, the cell count value X is initialized to 0 in the case of the JW method and X-1 in the case of the MW method.

[0021]

As described above, conventionally, the number of arriving cells is counted for each monitoring period Pn and the count value X is compared with the permissible value N so that the arriving cell is a violating cell. Whether or not it is determined.

However, in such a configuration, the AT
There has been a problem that it is not possible to cope with the delay variation on the time axis of the cell that occurs in the M communication network.

That is, in the ATM communication network, a delay fluctuation called a delay fluctuation occurs on the time axis of the cell.
When this delay fluctuation occurs, a difference occurs between the cell transmission pattern when it is transmitted from the terminal and the cell reception pattern when it arrives at the cell diversion monitoring device.

In the conventional policing method, strict policing is performed even with respect to this delay fluctuation. Therefore, even if the terminal transmits cells according to the declared values, normal cells may be regarded as violating cells due to policing.

An example of the above determination error will be described below with reference to FIG.

FIG. 6 shows a case where, for example, in the JW system shown in FIG. 2, the leading cell C4 of the monitoring period P2 shifts to the monitoring period P1 due to delay fluctuation.

Now, the allowable value is set to 3. In the case of FIG. 2, the cell count value X in each monitoring period P1, P2, P3, ...
Are 2, 3 and 3, respectively. Therefore, in this case, no violating cell is detected in any of the monitoring periods P1, P2, P3.

On the other hand, in the case of FIG. 6, each monitoring period P
The cell count values X at 1, P2, P3, ... Are 4, 1, 2 ,. Therefore, in this case, the cell C4 is determined to be a violating cell in the monitoring period P1.
As a result, the normal cell C4 is determined to be a violating cell.

Although a detailed description is omitted, such a problem also occurs in the MW window system.

The present invention has been made in order to cope with the above situation, and provides a cell flow rate monitoring device capable of reducing a determination error such that a normal cell is regarded as a violation cell due to delay fluctuation. The purpose is to

[0031]

In order to achieve the above-mentioned object, the present invention sets a monitoring period sequentially at a predetermined timing, and a cell is sent according to the declared value for each monitoring period. In a cell flow rate monitoring device that monitors whether or not there is a violating cell that counts arriving cells for each monitoring period and, when this cell count value exceeds a predetermined threshold value, regards the arriving cell as a violating cell. Means and cell count value advancing means for advancing the count value of normal cells exceeding the allowable value to the cell count value of the next monitoring period at the end of each monitoring period.

[0032]

In the above structure, the number of arriving cells is counted for each monitoring period, and when the cell count value exceeds a predetermined threshold value, the arriving cell is regarded as a violating cell. In this case, the count value of the normal cell whose cell count value exceeds the allowable value is moved up to the cell count value of the next monitoring period.

With such a configuration, a normal cell whose cell count value exceeds the allowable value is regarded as an arriving cell in the next monitoring period and is used for monitoring in this monitoring period. As a result, it is less likely that a cell that has shifted from the adjacent monitoring period due to delay fluctuation will be regarded as a violating cell, and thus it is possible to reduce decision errors.

When the cell count value exceeds a predetermined threshold value larger than the allowable value, the arriving cell is regarded as a violating cell. Therefore, even in the case of a report violation, the number of the violating cells regarded as a normal cell is set. Finally, it can be limited to the difference between the predetermined threshold and the tolerance. In this way, even in the case of this declaration violation, it is possible to take sufficient measures.

[0035]

Embodiments of the present invention will now be described in detail with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of the first embodiment of the present invention. Note that FIG. 1 shows an example of a configuration when the present invention is applied to a JW system cell flow rate monitoring device.

The apparatus shown in the figure has selection circuits (SEL) 11 to 11.
14, an arithmetic circuit (ALU) 15, and a register (RE
G) 16, a comparison circuit (COMP) 17, a cell detection circuit 18, a control circuit 19, and a violating cell processing circuit 20.

Here, the selection circuit 11 and the arithmetic circuit 15
Then, the register 16 has a function of counting the number of arriving cells during the monitoring period.

The comparator circuit 17 determines whether or not the cell count value X has reached a predetermined threshold value TH that is larger than the allowable value N during the monitoring period, and at the end of the monitoring period, the cell count value X is allowable. It has a function of determining whether or not the value N is exceeded. The comparison circuit 14 has a function of switching one input (determination criterion) of the comparison circuit 17 between the monitoring period and the end of the monitoring period.

The selection circuit 12 and the arithmetic circuit 15 have a function of obtaining an initial value of the cell count value X in the next monitoring period based on the judgment result of the comparison circuit 17 at the end of the monitoring period. The selection circuit 13 has a function of switching one input of the arithmetic circuit 15 between the monitoring period and the end of the monitoring period.

The cell detection circuit 18 has a function of detecting a cell from the reception input of the cell. The control circuit 19 controls various control signals RESET, MODE, L based on the detection output of the cell detection circuit 18 and the output of a timer circuit (not shown).
It has a function of outputting AT. Violation cell processing circuit 20
Has a function of performing a predetermined process on a cell regarded as a violating cell based on the determination result of the comparison circuit 17.

As shown in FIG. 7, the selection circuits 11 to 14 select the signal supplied to the input terminal A0 when the signal supplied to the control terminal S is 0, and select 1 when the signal supplied to the control terminal S is 0. The signal supplied to the input terminal A1 is selected.

Further, as shown in FIG. 8, the arithmetic circuit 15 adds the signals supplied to the input terminals A and B when the signal supplied to the control terminal OP is 0, and adds 1 when the signal supplied to the control terminal OP is 1. The signal supplied to the input terminal A is subtracted from the signal supplied to the input terminal A.

Further, as shown in FIG. 9, the comparison circuit 17 determines that if the judgment condition P = Q or P> Q is satisfied,
Set the corresponding output to 1, otherwise set to 0.

The selection operation of the selection circuit 11 is performed by the comparison circuit 17
The control is performed based on the determination result output from the output terminal O1 of, that is, the determination result of whether the cell count value X has reached the threshold value TH.

The selection operation of the selection circuit 12 is performed by the comparison circuit 17
The control is performed based on the determination result output from the output terminal O2, that is, whether the cell count value X exceeds the allowable value N.

The selection operation of the selection circuits 13 and 14 and the operation operation of the operation circuit 15 are controlled based on the mode switching signal MODE output from the control circuit 19. The mode switching signal MODE is set to 0 at the start of each monitoring period and temporarily set to 1 at the end of each monitoring period.

The register 16 has a reset signal RES output from the control circuit 19 when the cell flow monitoring device is activated.
It is reset to 0 by ET. Also, this register 1
6 is an arithmetic circuit 15 according to a latch signal LAT output from the control circuit 19 at the time of cell arrival and at the end of the monitoring period.
Latch the operation result of.

The operation of the above configuration will be described.

When the cell flow rate monitoring device is activated, the register 16 causes the reset signal R output from the control circuit 19 to be output.
Reset by ESET. As a result, the cell count value X output from the register 16 becomes zero. Also,
In this state, the determination result output from the output terminal O1 of the comparison circuit 17 is 0. As a result, 1 is selected in the selection circuit 11.

In this state, when the first monitoring period is started, the mode switching signal MODE becomes 0. As a result, the selection circuit 13 selects the selection output of the selection circuit 11. Further, in the arithmetic circuit 15, the cell count value X and the selected output of the selection circuit 13 are added. This allows
1 is output from the arithmetic circuit 15.

The selection circuit 14 selects the threshold value TH. As a result, in the comparison circuit 17, this threshold value TH
And the cell count value X are compared.

In this state, when the first cell arrives, the control circuit 19 outputs the latch signal LAT.
As a result, the addition output 1 of the arithmetic circuit 15 becomes the register 16
Latched on. As a result, the cell count X becomes 1,
The addition output of the arithmetic circuit 15 becomes 2. This addition output 2
Is latched in the register 16 at the next cell arrival timing. As a result, the cell count value X becomes 2, and the addition output of the arithmetic circuit 15 becomes 3.

Similarly, the cell count value X is updated by 1 each time a cell arrives. As a result, the arrival cells are counted.

As a result of this counting, the cell count value X is the threshold value TH.
When it reaches, the determination result output from the output terminal O1 of the comparison circuit 17 is switched from 0 to 1. As a result, 0 is selected in the selection circuit 11. As a result, cell counting is effectively stopped from the next arriving cell.

In the violating cell processing circuit 20, the next arriving cell is regarded as a violating cell. The arrival cell regarded as a violation cell is converted into, for example, a header of an empty cell. This causes the violating cell to be discarded at this point. On the other hand, the cell count value X is the threshold value T
If it does not reach H, the arriving cell is considered to be a normal cell and its count is made.

When the first monitoring period ends, the mode switching signal MODE is temporarily switched from 0 to 1.
As a result, the selection circuit 13 selects the selection output of the selection circuit 12. In addition, the arithmetic circuit 15 performs a process of subtracting the selected output of the selection circuit 13 from the cell count value X.

Further, the selection circuit 14 selects the allowable value N. As a result, in the comparison circuit 17, the cell count value X
Is determined to exceed the allowable value N.

If the cell count value X exceeds the allowable value N,
The output of the output terminal O1 becomes 1. As a result, the selection circuit 12 selects the allowable value N. As a result, the operation circuit 15 performs the operation X-N. Thereby, the count value of the normal cell in which the cell count value X exceeds the allowable value N is obtained.

On the other hand, if the cell count value X does not exceed the allowable value N, the output from the output terminal O1 becomes 0. As a result, the selection circuit 12 selects the cell count value X. As a result, in the arithmetic circuit 15, the operation X-X is performed. As a result, the calculation result of the calculation circuit 15 becomes zero.

The calculation result of the calculation circuit 15 is latched in the register 16 by the latch signal LAT which is output immediately after the mode switching signal MODE becomes 1. As a result, when the cell count value X exceeds the allowable value N, the register 16 latches the count value of a normal cell in such a state, and when it does not exceed 0, it is latched.

The data latched in the register 16 becomes the initial value of the cell count value X in the next monitoring period. This allows
When the cell count value X exceeds the allowable value N, a normal cell in such a state is regarded as an arrival cell in the next monitoring period.

In the next monitoring period, similarly to the first monitoring period, the violation cell is detected. When the cell count value X exceeds the allowable value N, the difference X−N between the two is moved up to the initial value X of the next monitoring period. Hereinafter, similarly, the processing as described above is performed for each monitoring period.

FIG. 10 shows the above-mentioned operation upon arrival of the cell.
It is represented by a flow chart for comparison with the conventional operation. Similarly, FIG. 11 is a flowchart showing the operation at the end of the monitoring period for comparison with the conventional operation.

When the cell arrives, as shown in FIG. 10, first, it is determined whether or not the cell count value X up to the previous cell arrival has reached the threshold value TH (step S3).
1). If not, the cell count value X is incremented by 1 (step S32). On the other hand, if the number of times of arrival is reached, a violation process of the arrival cell is performed (step S3).
3). After this, the cell returns to the waiting state, and when the next cell arrives, the above-mentioned processing is performed again.

At the end of the monitoring period, as shown in FIG. 11, first, it is determined whether the cell count value X exceeds the allowable value N (step S41). If it exceeds, the initial value of the cell count value X is set to the difference X-N between them (step S42). On the other hand, if not exceeded, the cell count value X is set to 0 (step S4).
3). After this, the start processing of the next monitoring period is performed.

According to this embodiment described in detail above, the following effects can be obtained.

(1) Even if the cell count value X exceeds the allowable value N, the arriving cell is not regarded as a violating cell, and the count value of such a cell is moved up to the cell count value of the next monitoring period. Therefore, it is possible to reduce the determination error that a normal cell is determined to be a violating cell due to delay fluctuation.

This will be described below with reference to FIG. 6 described above.

Now, the threshold value TH is set to 6. Further, in the monitoring period P1, it is assumed that there is no advance from the previous monitoring period. In this case, the cell count value X in the monitoring period P1 is
The number is 4, which is the same as the number of cells arriving in the monitoring period P1. The cell count value 4 is one more than the allowance value 3. Therefore,
In the conventional cell flow rate monitoring device, the cell C4 is regarded as a violation cell.

However, in this embodiment, if the cell count value X does not exceed the threshold value 6, the arriving cell is not regarded as a violating cell. Therefore, in this example, cell C4 is not considered a violating cell. In this case, 1 corresponding to the count value of the cell C4 is moved up to the cell count value X in the next monitoring period P2. As a result, the cell C4 is regarded as a cell that has arrived in the next monitoring period P2 and is involved in the monitoring in this monitoring period P2.

In the next monitoring period P2, the previous monitoring period P1
Since the cell count value X is 2
Becomes However, this cell count value 2 is also smaller than the threshold value 6. Therefore, even in this monitoring period P2, no violating cell is detected.

As described above, according to this embodiment, even if the delay fluctuation occurs, it is highly possible to obtain the same monitoring result as in the case where the delay fluctuation does not occur. This makes it possible to reduce judgment errors.

(2) Further, according to this embodiment, a predetermined threshold value TH larger than the allowable value N is set, and when the cell count value X exceeds this threshold value TH, the arriving cell is regarded as a violating cell. Therefore, it is possible to take sufficient measures even in the case of a report violation. Even in this case, this is the maximum TH-
This is because it can be limited to N.

(3) Further, the count value of the normal cells whose cell count value X exceeds the allowable value N is set to the cell count value X of the next monitoring period.
Cell count value X during this monitoring period
Since it is set as the initial value of, the carrying configuration can be simplified.

FIG. 12 is a block diagram showing the configuration of the second embodiment of the present invention. In addition, in FIG.
Portions having the same function as are given the same reference numerals and detailed description thereof will be omitted.

In the above embodiment, an example of the configuration in the case where the present invention is applied to the JW type cell flow rate monitoring device has been described. On the other hand, this embodiment shows an example of the configuration when the present invention is applied to the MW type cell flow rate monitoring device.

In the case of the JW system, the initial value of the cell count value X is originally 0. Therefore, like this invention,
When the cell count value X exceeds the allowable value N, the difference X-N between them
, The cell count value X
Requires a function of determining whether or not exceeds the allowable value N, and a function of switching the initial value of the cell count value X in the next monitoring period based on the determination result of this determination function.

On the other hand, in the case of the MW system, the initial value of the cell count value X is the value obtained by subtracting 1 from the cell count value X of the previous monitoring period. With such a configuration, even when the cell count value X exceeds the allowable value N, the cell count value X of the next monitoring period can be simply subtracted by 1 from the cell count value X of the previous monitoring period. The initial value of can be set.

As a result, in this embodiment, as shown in FIG. 12, the function of judging whether the cell count value X exceeds the allowable value N and the next monitoring based on the judgment result of this judgment function. The function of switching the initial value of the cell count value X of the period is unnecessary.

That is, in the previous embodiment, the comparison circuit 17
In addition, it is necessary to provide a function of determining whether the cell count value X has reached the threshold value TH and a function of determining whether the cell count value X has exceeded the allowable value N. On the other hand, in this embodiment, the comparison circuit 31 need only be provided with the function of determining whether or not the cell count value X has reached the threshold value TH.

Further, in the previous embodiment, the selection circuit 12 for switching the initial value based on the judgment result of the comparison circuit 17 was required. On the other hand, in this embodiment, the selection circuit 12 is unnecessary.

Since the function of determining whether or not the cell count value X exceeds the allowable value N is unnecessary, the comparator circuit 14 is also unnecessary in this embodiment.

Further, in this embodiment, since the data 1 input to the selection circuit 11 can be used as the subtraction data 1 for obtaining the initial value, the selection circuit 13 is also unnecessary. However, in order to realize the shared use of this data, in this embodiment, an inverter 32 and an AND circuit 3 are newly added.
3 is provided.

The operation of the above configuration will be described.

At the start of each monitoring period, the mode switching signal M
ODE is set to 0. As a result, the inverter 32
Output becomes 1. Therefore, the output of the AND circuit 33 is determined by the determination result output from the output terminal O of the comparison circuit 31.

That is, if the cell count value X has not reached the threshold value TH, this determination result becomes 0. This allows
The output of the AND circuit 33 also becomes 0. On the other hand, when the cell count value X reaches the threshold value TH, the determination result becomes 1. As a result, the output of the AND circuit 33 also becomes 1.

When the output of the AND circuit 33 is 0, the selection circuit 11 selects 1. As a result, the cell count value X
Is updated by 1 each time a cell arrives. On the other hand, when the output of the AND circuit 33 becomes 1, the selection circuit 1
In 1, 0 is selected. As a result, the cell count value X
Is fixed to the threshold TH.

When the monitoring period ends, the mode switching signal M
When ODE temporarily becomes 1, the output of the AND circuit 33 is temporarily set to 0 regardless of the determination result of the comparison circuit 31. As a result, 1 is selected in the selection circuit 11. As a result, the cell count value X in the next monitoring period
The initial value X-1 of X is obtained.

FIG. 13 is a flow chart showing the operation at the end of the monitoring period of this embodiment. As shown, the operation in this case is the same as the conventional operation.

Also in this embodiment described in detail above, the same effect as in the previous embodiment can be obtained.

14 and 15 are flow charts showing the operation of the third embodiment of the present invention.

In the first and second embodiments described above, the case has been described in which the number of arriving cells is counted from the initial value to the threshold value TH by one counting circuit. On the other hand, in this embodiment, the first counting circuit for counting from the initial value to the allowable value N and the allowable value N
From the initial value to the threshold value TH by the second counting circuit for counting from the initial value to the threshold value TH.

FIG. 14 is a flow chart showing the operation upon arrival of a cell in this case. Similarly, FIG. 15 is a flowchart showing the operation at the end of the monitoring period.

In the figure, X1 is the cell count value of the first counting circuit, and X2 is the cell count value of the second counting circuit.

When the cell arrives, as shown in FIG. 14, first, it is determined whether or not the cell count value X1 of the first counting circuit up to the previous cell arrival has reached the allowable value N ( Step S61).

If the allowable value N has not been reached, the cell count value X1 is incremented by 1 (step S6).
2). On the other hand, if the allowable value N is reached, the cell count value X2 of the second counting circuit until the last cell arrival is (T
H-N) is determined (step S
63).

If (TH-N) has not been reached, the cell count value X2 is incremented by 1 (step S6).
4). On the other hand, when (TH-N) is reached, the arriving cell is regarded as a violating cell, and predetermined violation processing is performed (step S65). When the above processing is completed, the cell returns to the waiting state, When the next cell arrives, the processing as described above is executed again.

At the end of the monitoring period, first, as shown in FIG.
As shown in 5, the process of setting the cell count value X1 to the original initial value is performed (step S71). That is, J
In the W method, the cell count value X1 is set to 0, and in the MW method, it is set to X1-1.

Next, it is determined whether or not the cell count value X2 is 1 or more (step S72). In other words, it is determined whether the cell count value X1 + X2 exceeds the allowable value N.
If it does not exceed, the processing ends. On the other hand, if it exceeds, processing for advancing the cell count value X2 to the next monitoring period is performed (steps S73 to S7).
5).

This process is performed by decreasing the cell count value X2 by 1 and increasing the cell count value X1 by 1 (steps S73, S74). In addition, this processing is performed until the cell count value X2 becomes 0 (step S7).
2) Alternatively, the process is continued until the cell count value X1 reaches the allowable value N (step S75).

If the above process is continued until the cell count value X2 becomes 0, the initial value of the cell count value X1 in the next monitoring period becomes (X1−X0) + X2, and the initial value of the cell count value X2 becomes The value is 0. On the other hand, when the above process is continued until the cell count value X1 becomes the allowable value N, the initial value of the cell count value X1 in the next monitoring period becomes N, and the initial value of the cell count value X2 becomes X2- {N-
(X1-X0)}.

According to this embodiment described in detail above, since the initial setting of the two counting circuits is required, the initial setting configuration is more complicated than that of the previous embodiment, but the reduction of the determination error is performed by the previous embodiment. The same effect as the example can be obtained.

Although the three embodiments of the present invention have been described in detail above, the present invention is not limited to the above-described embodiments.

(1) For example, in the first to third embodiments described above, when the count value X-N of the normal cells whose cell count value X exceeds the allowable value N is advanced to the next monitoring period, The case where the count value X-N is advanced as the initial value of the cell count value X in the next monitoring period has been described. However, in the present invention, the cell count value X in consideration of the carry amount may be output by adding the count value X-N and the original cell count value in the next monitoring period in the adding circuit. .

According to such a configuration, since the adder circuit is required, the cell counting configuration becomes complicated.
In the configuration in which the number of arriving cells is counted by one counting circuit as in the second embodiment, the complication of this configuration does not cause much problem.

(2) In the first to third embodiments, when the cell count value X exceeds a predetermined threshold value TH, not only the arriving cell is regarded as a violating cell, but also the count of this cell is counted. The case of stopping is explained. However, in the present invention, the counting of the arriving cells may not be stopped as long as the arriving cells are regarded as the violating cells. However, in this case, a separate configuration is required to prevent the counting value (X-TH) of the violating cell from being increased.

(3) Further, in the above embodiment, the case where the present invention is applied to the cell flow monitoring apparatus of the JW system and the MW system has been described. However, the present invention can also be applied to, for example, a trigger window type cell flow monitoring device that starts a monitoring period in synchronization with the arrival timing of cells.

(4) In addition to this, it is needless to say that the present invention can be variously modified without departing from the scope of the invention.

[0110]

As described in detail above, according to the present invention, there is provided a cell flow rate monitoring device capable of reducing a determination error such that a normal cell is regarded as a violation cell due to delay fluctuation. be able to.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a first exemplary embodiment of the present invention.

FIG. 2 is a timing chart showing a JW system.

FIG. 3 is a timing chart showing the MW system.

FIG. 4 is a flowchart showing a conventional operation upon arrival of a cell.

FIG. 5 is a flowchart showing an operation at the end of a conventional monitoring section.

FIG. 6 is a timing chart for explaining a conventional problem.

FIG. 7 is a diagram showing a truth table of a selection circuit.

FIG. 8 is a diagram showing a truth table of an arithmetic circuit.

FIG. 9 is a diagram showing a truth table of a decision circuit.

FIG. 10 is a flowchart showing an operation when a cell arrives according to the first embodiment.

FIG. 11 is a flowchart showing an operation at the end of the monitoring section of the first embodiment.

FIG. 12 is a block diagram showing a configuration of a second exemplary embodiment of the present invention.

FIG. 13 is a flowchart showing an operation at the end of the monitoring section of the second embodiment.

FIG. 14 is a flowchart showing an operation upon arrival of a cell according to the third embodiment of the present invention.

FIG. 15 is a flowchart showing an operation at the end of the monitoring section of the third embodiment.

[Explanation of symbols]

11 to 14 ... Selection circuit, 15 ... Arithmetic circuit, 16 ... Register, 17, 31 ... Judgment circuit, 18 ... Cell detection circuit, 19
... control circuit, 20 ... violating cell processing circuit, 32 ... inverter, 33 ... AND circuit.

Claims (1)

[Claims] 1. A monitoring period having a time width defined by a declared value of a communication band of a cell is sequentially set at a predetermined timing, and a cell is sent according to the declared value for each monitoring period. In the cell flow rate monitoring device for monitoring whether or not there is an arrival cell for each monitoring period, and when the cell count value exceeds a predetermined threshold value larger than the allowable value defined by the declared value, the arrival cell is detected. Violation cell detection means regarded as a violation cell, and cell count value advancing means for advancing the count value of a normal cell whose cell count value exceeds the allowable value at the end of each monitoring period to the cell count value of the next monitoring period. And a cell flow rate monitoring device.