JPH06164626A - Cell loss/misdistribution testing device - Google Patents

Abstract

PURPOSE:To generate the test data at the cell receiver side in regard of a cell loss/misdistribution testing device which measures the loss and the misdistribution of cells in the packet communication. CONSTITUTION:A cell loss/misdistribution testing device contains a cell loss/ misdistribution test data generating means 3. The means 3 is provided with an arriving cell input part 10, an arriving cell counting part 11, a loss test data generating part 12 which generates the test data on a loss mode in accordance with the count value of the part 11 or a misdistribution test data generating part 13 which generates the test data on a misdistribution mode, a test mode selecting part 14 which selects the loss test data or the misdistribution test data, and an invalid flag generating part 15 which generates an invalid flag to invalidate the arriving cells based on the test data selected by the part 14.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention eliminates cell loss (a state where a cell is not delivered) or misdelivery (a state where a cell is delivered to the wrong partner) in a data communication system that transmits packet data as a cell. Cell loss to measure
A misdelivery test device.

In such a cell loss / misplacement test apparatus, test data may be generated to perform a test simulation. In that case, test data for cell loss / misdelivery is required, but it is not easy to create such test conditions on the transmission side of the system and insert them as test data. Therefore, there is a demand for a test apparatus that can easily generate test data for cell loss or cell misdistribution on the test apparatus side.

The present invention relates to a cell loss / mis-delivery test device capable of easily producing test data of cell loss or mis-delivery in a test device based on a normally arriving cell.

[0004]

2. Description of the Related Art FIG. 5 shows a data communication system targeted by the present invention (the figure shows a case where a loss / mis-delivery test of a cell transferred to a receiver A (102) is performed).

In the figure, 90 is a data communication system,
Reference numeral 100 is a transmitter, 101 is a data exchange network, and a cell in which data is packetized is transmitted from the transmitter 100 to a receiver A (102), a receiver B (103), and a receiver C (1
It is a system to transfer to 04). 102 is a receiving device A, 103 is a receiving device B, and 104 is a receiving device C.
Reference numeral 105 denotes a cell loss / misdelivery test device, which is a device for measuring cell loss or misdelivery. Reference numeral 106 represents a test result output.

In the data exchange network 101, 110 is transmission data and represents packetized data. 111
Is a cell and represents packetized data. A
1 and A2 are the first addressed to the receiver A (102),
This is the second cell. B1 and B2 are receivers B, respectively
These are the first and second cells addressed to (103). C1 is a packet addressed to the receiving device C (104).

In the configuration shown in FIG.
The transmission data 110 is transmitted to the data exchange network 101.
The data exchange network 101 allocates each cell of the transmission data 110 to each destination. Each of the distributed cells is the receiver A (102) and the receiver B (10) of the respective destinations.
3), and is transferred to the receiving device C (104).

Next, let us consider a case where a loss / misdistribution test of cells transferred in the receiver A (102) is performed. The reception cells of the reception device A (102) are sequentially input to the cell loss / misdistribution test device 105. The cell loss / mis-delivery test device compares the cell number of the input cell with the number of input cells, detects the number of cell losses or mis-delivery, and outputs the test result.

FIG. 6 shows a conventional cell loss / misdistribution test apparatus. In the figure, 105 is a cell loss / misdistribution test device, 1
Reference numeral 20 is a sequence number input section for inputting the sequence number (SN) of the input cell.
A reference sequence number generation unit 121 counts the number of input cells. Reference numeral 122 denotes a loss / mis-delivery detection unit, which is a cell sequence number (S
N) is compared with the reference sequence number (SNR) to detect cell loss or misdelivery. Reference numeral 123 is a reference sequence number correction unit, so that when the cell sequence number (SN) and the reference sequence number (SNR) differ due to loss or misdistribution, the reference sequence number matches the cell sequence number. It is something to fix. Reference numeral 124 represents a test result output.

The operation of the configuration shown in the figure will be described. The cells are given a sequence number SN in the order of generation. If the sequence number is N bits, the sequence number is 0 to (2 ^N -1) and is sequentially added in the order of generation. Cell loss / misdelivery tester 10
In 5, the sequence number input unit 120 detects the sequence number SN of the input cell. The reference sequence number generation unit 121 counts the number of cells that are sequentially input and generates a reference sequence number (SNR).

In order to detect cell loss and misdelivery,
The misdelivery detection unit 122 determines that the cell loss / misdelivery number A = [2 ^N + (S
N-SNR)] MOD2 ^N ([2 ^N + (SN-SN
R)] ÷ 2 ^N remainder) is calculated, and when 0 <A ≦ (2 ^N−1 −1), it is determined that there are A cell losses (discards).

When 2 ^N−1 ≦ A ≦ (2 ^N −1), (2
^N- A) It is determined that there is an erroneous cell distribution. Then, the loss / misplacement detection unit 122 outputs the determination result.

FIG. 7 is an explanatory diagram of the cell loss / misplacement test method. (a) shows the case with cell loss. The figure shows the case where the cell with the sequence number SN = 3 is lost (discarded). The sequence number input unit 120 detects the sequence number of the arriving cell. The cell with sequence number 3 has been lost, so the order of arrival cells is 1, 2,
4, 5, 6, ... Are detected.

The reference sequence number generation unit 121 increments the cell number by 1 every time a cell is input and counts the input cell number. That is, when SN = 1, SNR =
As 1, the loss / misdistribution detection unit 122 calculates A = 0 based on SN and SNR. Similarly, when SN = 2, 1 is added to the previous SNR to set SNR = 2. The loss / misdistribution detection unit 122 calculates A = 0 based on the values of SN and SNR. Furthermore, the sequence number input unit 120
Since N = 3 cells are lost and SN = 4 cells arrive, SN = 4 is detected. The reference sequence number generation unit 121 adds 1 to the previous SNR to set SNR = 3. Then, the loss / misdelivery detection unit 122 uses the SN and SN
The loss number A = 1 is calculated based on the value of R. Therefore, the reference sequence number correction unit 123 corrects the count value of the reference sequence number generation unit 121 to 3. After that, cell loss and misdelivery are similarly detected.

(B) shows the case where there is a cell mis-delivery. The figure shows the case where the cell that has arrived following the sequence number SN = 2 of the arriving cell is mis-delivered (cells of other destinations have arrived).

The sequence number input unit 120 detects the sequence number SN = 1 of the arriving cell. And
The reference sequence number generation unit 121 sets SNR = 1. The loss / misdistribution detection unit 122 calculates misdistribution number = 0 with SN = 1 and SNR = 1. Next, the sequence number input unit 120 detects the sequence number SN = 2 of the arriving cell. Then, the reference sequence number generation unit 121
Causes 1 to be added to the previous SNR = 1 to set SNR = 2. The loss / misdistribution detection unit 122 has SN = 2 and SNR = 2.
The false distribution number A = 0 is calculated based on. Next, the mis-distributed cells are input. The sequence number input unit 120 does not detect the sequence number because it is the cell number of another destination.
The reference sequence number generation unit 121 uses the previous SNR =
1 is added to 2 to set SNR = 3. Next, the cell with the sequence number SN = 3 arrives. Sequence number input unit 120 detects SN = 3. The reference sequence number generation unit 121 uses the reference sequence number SN of the previous time.
1 is added to R to set SNR = 4. Loss / misdelivery detector 1
22 calculates the wrong distribution number = 1 based on the sequence number SN = 3 and SNR = 4. The reference sequence number correction unit 123 corrects the reference sequence number to the sequence number SN = 3 of the current arrival cell. Thereafter, loss and misdelivery are similarly detected.

FIG. 8 shows a test data insertion method of a conventional loss / misdistribution test apparatus. In the figure, 90 is a data communication system, 100 is a transmitting device, 101 is a data switching network, 102 is a receiving device, 105 is a cell loss / misdistribution test device, and 106 is a test result output unit. 107 is a loss / misdelivery test data input unit.

In the figure, when it is necessary to insert the loss / misdistribution test data in the loss / misdistribution test, the loss / misdistribution test data is created and the loss / misdistribution test data input unit 1 is used.
Enter from 07. The loss / misdelivery test data is transferred to the receiving device 102 via the data exchange network 101. The cell loss / mis-delivery test device 105 inputs the cell loss / mis-delivery data and outputs the test result to the test result output unit 106.

[0019]

As described above, in the cell loss / misdistribution test device, the loss or misdistribution test data is inserted on the data transmission side.

However, in a loss / misdistribution simulation test or the like, the test data may be inserted on the receiving side, and it is easy to create and insert the loss / misdistribution test data on the transmitting side. There wasn't.

It is an object of the present invention to provide a cell loss / misdistribution test device which can easily generate loss / misdistribution test data.

[0022]

SUMMARY OF THE INVENTION The present invention automatically obtains loss and misdistribution test data based on a cell that is normally input to a cell loss / misdistribution test device (hereinafter abbreviated as a test device). I tried to generate it.

FIG. 1 shows the basic configuration of the present invention. In the figure, 1 is a cell loss / mis-delivery test device. Reference numeral 2 is a sequence number input section for inputting a sequence number of a cell which is normally transferred. Reference numeral 3 is a cell loss / misdistribution test data generating means for generating the loss / misdistribution test data based on a cell which is normally input. Reference numeral 4 is a testing means for measuring cell loss and misdelivery.

In the cell loss / misallocation test data generating means 3, 10 is an arrival cell input section for inputting a cell which is normally input. An arrival cell counting unit 11 counts the number of normally input cells. 12 is a loss test data generator,
It is intended to generate cell loss test data. Reference numeral 13 denotes an erroneous distribution test data generation unit, which generates erroneous distribution test data for cells. The setting of the loss mode and the erroneous distribution mode is distinguished by the count value of the arrival cell counting unit 11. For example, in the loss mode, when the count value is 1 to (2 ^N-1 -1), cells in the meantime are invalidated intentionally. In the misdelivery mode, the count value is 2 ^N-1 to (2
It is generated by invalidating the test cell at the time of ^N −1). A test mode selection unit 14 selects a loss mode or an erroneous distribution mode. An invalid flag generator 15 outputs a signal that intentionally invalidates ¹ to (2 ^N-1 -1) cells among the arriving cells when the loss mode is designated, and the misdelivery mode is set. Is generated, a signal for invalidating the cells of 2 ^N-1 to (2 ^N -1) is generated. Reference numeral 16 denotes a loss / misdistribution test data generation unit, which invalidates a number of test cells defined according to the invalid flag based on the arrival cell (test cell) and the invalid flag and generates loss or invalid test data. It is a thing. Reference numeral 17 is a loss / misdelivery test data output unit.
Reference numeral 18 denotes a test mode setting unit, which inputs the set values of the loss test data generation unit 12 and the misdistribution test data generation unit 13 and designates the mode selection of the test mode selection unit 14.

[0025]

FIG. 2 is a diagram for explaining the operation of the basic structure of the present invention.
In the figure, (a) is an arrival cell (hereinafter referred to as a test cell), which is a test cell input to the arrival cell input unit 10. (b) is a test mode signal indicating that the test is in progress. (c) is an invalid flag (loss) and represents an invalid flag output when the loss mode is selected. (d)
Is loss test data, and shows the loss mode test data output. (e) is an invalid flag (mis-delivery) and represents an invalid flag output when the mis-delivery mode is selected. (f) is misdelivery test data, and shows test data output in misdelivery mode.

The operation of the basic configuration of FIG. 1 will be described with reference to FIG. In the loss test data generation unit 12, the count value for invalidating the test cell in the loss mode is set in advance by the test mode setting unit 18. Similarly, the count value for invalidating the test cell in the mis-distributed mode is set in advance in the mis-distributed test data generation unit 13. For example, a count value of 1 to 3 is a loss mode, and a count value of 4 to 7 is an erroneous distribution mode (when the aforementioned sequence number is composed of 3 bits (N = 3)).

The test cell (a) is sequentially input to the arrival cell input unit 10. When the test mode (b) is under test, the arrival cell counting unit 11 sequentially counts the number of test cells that arrive.

It is assumed that the test mode selection unit 14 has selected the loss mode. Then, the loss test data generation unit 12 outputs, for example, “1” until the value 2 is set and the arrival cell counting unit 11 counts two test cells,
When the count value is 3 or more, "0" is output.

A case where the loss test data is generated will be described. The test mode selection unit 14 selects the output of the loss test data generation unit 12 and inputs it to the invalid flag generation unit 15. The invalid flag generation unit 15 outputs the invalid flag (c) of "1" during the period in which two test cells are input and "0" after that, according to the output of the arrival cell counting unit 11. The loss / misdelivery test data generation unit 16 includes a test cell (a) input to the arrival cell input unit 10 and an invalid flag generation unit 1.
On the basis of the invalid flag (loss) (c) generated by 5, the test data (d) in which only two test cells are invalid is generated, and the loss / misdistribution test data output unit 17 outputs the loss test data ( Output d).

A case of generating misdelivery test data will be described. The test mode selection unit 14 selects the output of the misallocation test data generation unit 13 and inputs it to the invalid flag generation unit 15. The invalid flag generation unit 15 outputs the invalid flag (c) of "1" during the period in which four test cells are input and "0" after that, according to the output of the arrival cell counting unit 11. The loss / misdelivery test data generation unit 16 includes a test cell (a) input to the arrival cell input unit 10 and an invalid flag generation unit 1.
Based on the invalid flag (misdistribution) (e) generated by 5, the test data (f) in which only four test cells are invalid is generated, and the loss / misdistribution test data output unit 17 causes the misdistribution test. Output data (f).

Although the case of 3 bits (N = 3) has been described above, by setting the counter of the arrival cell count unit 11 to N bits, the test cells arriving in the sequence number order are 1 to (2 ^{N). -1} -1) By invalidating, 1 to (2 ^N-1 -1) cell loss states can be realized. Further, by invalidating 2 ^N-1 to (2 ^N -1) test cells, 1 to (2 ^N-1 -1) erroneous cell distribution states can be realized.

The detection of the number of losses and the number of erroneous distributions by the test means 4 is determined by the method described above. That is, cell loss
Misdistribution A = [2 ^N + (SN-SNR)] MOD2
^N ([2 ^N + (SN-SNR)] ÷ remainder of 2 ^N ) is calculated, and when 0 <A ≦ (2 ^N-1 −1), it is determined that there are A cell losses (discards).

When 2 ^N−1 ≦ A ≦ (2 ^N −1), (2
^N- A) It is determined that there is an erroneous cell distribution.

[0034]

FIG. 3 shows an embodiment of the cell loss / misdistribution test data generating means of the present invention. In the figure, 30 is a loss misdistribution test data generation unit, 31 is a test start head cell generation unit, which outputs the first head cell input after the test mode is set, and outputs the subsequent cells as invalid. To do. Reference numeral 32 is an invalid flag generation unit. An arrival cell counting unit 33 is an N-bit counter. Reference numeral 34 denotes a loss test data generation unit, which has 1 to (2
^When it is set to the value of ( ^N-1 -1), "1" is output until the count value of the arrival cell count unit 33 reaches the set value, and when the count value exceeds the set value, "1" is output. "0" is output. Reference numeral 35 denotes an erroneous distribution test data generation unit, which is "1" until the count value of the arrival cell count unit 33 reaches the set value when it is set to a value of 2 ^N-1 to (2 ^N -1). Is output, and "0" is output when the count value exceeds the set value. Reference numeral 36 is a test mode selection unit, and 37 is a loss / misdistribution mode setting input unit.

An AND circuit 40 inputs an arriving cell (test cell) and a test mode (during test) and outputs an arriving cell (test cell) during the test. In the test start head cell generator 31, 42 is an inverter for inverting an input signal. Four
Reference numerals 3 and 44 are NOR circuits, and 45 is a flip-flop (FF).
Is. An AND circuit 46 outputs the signal at the beginning of the test start cell.

In the invalid flag generator 32, 47 is a NOR circuit and 48 is a JK-flip-flop. 49 is an AND circuit and 50 is a NAND circuit.

FIG. 4 shows a time chart of the loss / misdelivery test data generating means of the present invention. (a) is the arrival cell head (test cell), and (b) is the test mode signal, which is set during the test. (c) represents the beginning of the cell under test. (d) represents the beginning of the test start cell, (e) represents the invalid flag, and (f) represents the count value of the arrival cell count unit 33. (g) is the head of the detection cell and represents the generated test data.

The operation of the loss / misdistribution test data generating means of the present invention shown in FIG. 3 will be described with reference to FIG. The arrival cell head (test cell) (a) is input to the AND circuit 40. Since the test mode (b) is input to the other side of the AND circuit 40, if the test in progress is set, the AND circuit 4
The head of the arrival cell (test cell) is output from 0.

Since the initial value of the output Q of the flip-flop 45 of the test start head cell generator 31 is "0" and the initial value of Q'is "1", the arrival cell head (test cell) 61
Is output as the first (c) cell during the test via the AND circuit 46. On the other hand, the test mode (b) is input to the test start head cell generator 31, inverted, and input to the NOR circuit 44. When the test cell (arrival cell head) is input from the AND circuit 40 in the state of Q = 0, the output of the NOR circuit 43 becomes “0”, and the NOR circuit 44
Output is "1". Therefore, the flip-flop 45
Are inverted, and the outputs Q = 1, Q '= of the flip-flop 45
It becomes 0. After that, the output of the flip-flop 45 is Q =
1, Q '= 0 is held. Therefore, the AND circuit 46
Is not output for the cells following the first cell 61,
The beginning of the test start cell in (d) is obtained.

The initial value of the output of the invalid flag generator 32 is "0", and the invalid flag is "0". In this state, the cell at the beginning (d) of the test start cell is input to the J input terminal of the flip-flop 48 of the invalid flag generation unit 32. On the other hand, for example, the set value of the loss test data generation unit 34 is set to 3, and the test mode selection unit 36 sets the loss mode and selects the output of the loss test data generation unit 34.

The output of the loss test data generator 34 is "0" because the initial value of the count output is "0", and the initial value of the JK-flip-flop 48 is "0".
The output of the NAND circuit 50 is "1". Since the input of the NOR circuit 47 is "1" of the test start cell and the output "1" of the NAND circuit 50, its output is "0". Therefore,
The output of the flip-flop 48 becomes "1". The loss test data generation unit 34 continues to output “0” until the arrival cell counting unit 33 counts the set count value, and during that time, the value of the K input terminal of the flip-flop 48 is “0”. Therefore, the output of the flip-flop 48 holds "1". Therefore, since the output “1” of the flip-flop 48 is input to the AND circuit 49, each cell at the beginning of the cell under test (c) is input to the EN terminal of the arrival cell counting unit 33 via the AND circuit 49.

On the other hand, the test start cell head (d) is loaded into the load (Lo) of the arrival cell counting section 33 to start the operation. Since "1" is input to the D input terminal, each input cell at the beginning (c) of the cell under test is counted. When the count value of the arrival cell counting unit 33 indicates 3, the loss test data generating unit 34 outputs "1".
Therefore, the output of the NAND circuit 50 becomes "0", and the output "0" of the NAND circuit 50 and "0" of the test start cell head (d) are input to the NOR circuit 47 and become "1".
The output of flip-flop 48 is inverted. The invalid flag (e) is generated by the above operation.

Similarly, when the selection of the test mode selection unit 36 is set to the incorrect distribution, the incorrect distribution test data generation unit 35
Output is selected. Then, if the setting value of the erroneous distribution test data generation unit 35 is set to 7, the invalid flag (e) is set to "1" while the seven cells at the beginning (c) of the cell under test are input to the arrival cell counting unit 33. And after that, it becomes "0",
An invalidation flag (e) that invalidates seven test cells is generated.

Next, the loss misdistribution test data generation unit 30 generates test data from the test cell (a) and the invalid flag (e). Since the invalid flag (e) is input to the NOR circuit 41 ′ of the loss / misdistribution test data generation unit 30, no test cell is output while the invalid flag is “1”. Further, while the invalid flag is “0”, it is 1 when the output of the flip-flop 41 is 0, and 0 when the output of the flip-flop 41 is 1.
Output changes every time a test cell arrives, so the beginning of the detected cell (test data) depending on the loss mode or misdelivery mode
Output (g).

[0045]

According to the present invention, it is possible to easily create the test data of loss / mis-distributed cells in the cell loss / mis-disposition test device. Therefore, the simulation test of the data communication system can be easily performed.

[Brief description of drawings]

FIG. 1 is a diagram showing a basic configuration of the present invention.

FIG. 2 is an operation explanatory diagram of the basic configuration.

FIG. 3 is a diagram showing a cell loss / misallocation test data generating means of the present invention.

FIG. 4 is a diagram showing a time chart of the loss / misdelivery test data generating means of the present invention.

FIG. 5 is a diagram showing a data communication system targeted by the present invention.

FIG. 6 is a diagram showing a conventional cell loss / misallocation test device.

FIG. 7 is an explanatory diagram of a cell loss / misdelivery test method.

FIG. 8 is a diagram showing a test data insertion method of a conventional loss / misdistribution test device.

[Explanation of symbols]

 1: Cell loss / mis-delivery test device 2: Sequence number input unit 3: Cell loss / mis-delivery test data generation means 4: Testing means 10: Arrival cell input unit 11: Arrival cell count unit 12: Loss test data generation unit 13 : Misdistribution test data generation unit 14: Test mode selection unit 15: Invalid flag generation unit 16: Loss / misdistribution test data generation unit 17: Loss / misdistribution test data output unit

Claims (1)

[Claims] 1. A cell loss / mis-delivery test device for testing cell loss and mis-delivery in a system in which data is packetized and transmitted, wherein the cell loss / mis-delivery test device is cell loss and mis-delivery test data. Cell loss / misdistribution test data generation means
The cell loss / misallocation test data generating means (3) is provided with an arriving cell input unit (10) for inputting a normal series of test cells and an arriving cell counting unit (10) for counting the number of arriving cells. 11) and a loss test data generation unit (12) that generates loss mode test data according to the count value of the arrival cell count unit (11) or an erroneous distribution test data generation unit (12) that generates erroneous distribution mode test data. 13), a test mode selection unit (14) that selects loss mode test data or misdelivery mode test data, and an invalid cell that invalidates the arrival cell based on the test data selected by the test mode selection unit (14). An invalid flag generation unit (15) that generates a flag and an arrival cell and an invalid flag are input and the arrival cell is invalid if the invalid flag is set, and the arrival cell is valid if the invalid flag is not set. Loss and miscarriage test data generation unit that
(16) A cell loss / mis-delivery test device characterized by generating loss / mis-delivery test data.