JPH10145393A - Upc circuit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simplify circuit constitution, to reduce a hardware quantity, and to reduce cost by judging abnormality from the result of comparing an interval between cells at each virtual path identifier VPI and an interval between specific peak cells, with respect to a UPC circuit monitor-controlling the flow rate of continuously arriving cells. SOLUTION: VPI is separated from the transmitted cells to be sent to an OR gate 103 through respectively corresponding VPI identification parts 121 to 12N, to take a logical sum to send it to a ring counter 104 and a counter value storing part 105. An address generation part 106 sends an address generated according to VPI to a counter value storing part 105. A calculation part 107 obtains a difference between a count value at the point of a cell arriving time from the counter 104 and a count value in the part 105. A comparing and judging part 109 compares this difference value and the output of a peak cell interval storing part 108 and when the difference value is larger than a peak cell interval, judges the cell held in a cell delay part 110 to be normal and permits the passing of the cell through a cell control part 111.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a UPC circuit for monitoring and controlling the flow rate of cells by counting the interval between successively arriving cells specified by an arbitrary VPI.

[0002]

2. Description of the Related Art B-ISDN (Integrated)
As an effective transmission method for realizing the Services Digital Network (Asynchronous Service Digital Network), an asynchronous transfer mode (Asyn) for asynchronously transferring 53-byte fixed-length packets called cells, which is called a cell, is used.
chronic Transfer Mode: AT
M) is being developed. One of the important functions of this ATM is to individually set the traffic between each user and the carrier in order to avoid "congestion" in the communication network, and monitor the cell flow based on the traffic. Usage parameter control (Usage Parameter Con
(control: UPC) is known. With this feature,
If there is a cell violating the regulation, control for limiting the flow rate of the cell from the user, such as discarding the cell, is performed. Furthermore, in order to identify a cell, a virtual path identifier VPI (Virtual Path Identif) is used.
ier) is defined, and this VPI is added to the header of each cell. Usually, the device that realizes ATM is
It is composed of only hardware to ensure high speed data transmission. Therefore, the UPC is also configured by hardware and is called a UPC circuit.

FIG. 2 is a block diagram showing a conventional UPC circuit. In the figure, reference numeral 201 denotes a VP for separating the VPI
The I information separation units 221 to 22N are VPI identification units 1 to N. Reference numerals 231 to 23N denote cell monitoring units 1 to N for monitoring cell flow rates, and reference numerals 241 to 24N denote policing units. An OR gate 205 receives violation signals output from the cell monitoring units 1 to N, and outputs a logical sum of them.
206 is a cell delay unit that temporarily holds the cell unit,
A cell control unit 207 performs a process of passing or discarding a cell or adding a code to a cell, and a cell permitted to pass here is output as a normal cell. In this UPC circuit, a cell arriving at the circuit is a VPI information separating unit 2
At 01, the cell section and the VPI information are separated, and the cell section is temporarily held in the cell delay section 206. On the other hand, VPI
It is determined whether or not the information matches the preset VPI of each of the VPI identification units 1 to N 221 to 22N. 23N is notified to the corresponding cell monitoring unit. 23 of cell monitoring units 1 to N
In 1 to 23N, any method (algorithm)
, The flow rate of the cell is monitored. By the way, the above algorithms mainly include a TX method and a leaky bucket method. In the TX method, the flow rate of cells is monitored by counting the number of cells in a specified periodic period. Specifically, the number of cells of the same VPI transmitted during the period measured by the timer is measured, and when the number of cells measured within the period is equal to or less than a specified value, those cells are normal cells. If the number of cells is equal to or greater than the specified value, cells exceeding the specified value are marked as discarded or violating cells. In the leaky bucket method, the cell flow rate is monitored by measuring the interval between cells having the same VPI. Specifically, if the interval between an arbitrary cell and a cell having the same VPI immediately before it is equal to or greater than a specified value, the arbitrary cell is determined as a normal cell and transmitted as it is. If it is less than or equal to the value, this arbitrary cell is determined to be a violating cell,
A code indicating a discarded or violating cell is added.

[0004]

However, in the conventional example shown in FIG.
It is necessary to configure N for each of a plurality of different VPIs, and there is a problem that the scale of hardware of the entire UPC circuit becomes large. In order to solve this problem, Japanese Patent Laid-Open No. Hei 5-268239 (Fujitsu) proposes a single policing unit for the TX method, which is one of the methods (algorithms) for monitoring the flow rate of cells in a UPC circuit. Multiple V
By monitoring the flow rate of the CI cell, the
A method that does not require the use of a C circuit is proposed. However, the above problem has not been solved for the leaky bucket method which is another specific method (algorithm) of the UPC, and a policing unit has to be configured for each of a plurality of different VPIs. .

[0005]

SUMMARY OF THE INVENTION In a UPC circuit which is specified by an arbitrary identifier and monitors and controls the flow rate of cells by counting the intervals between cells arriving successively, an identifier of an input cell is assigned to each cell. An identifier separating unit to be separated;
A plurality of identification units connected to the identifier separation unit for identifying the separated identifiers; and an OR connected to the identification units and outputting a cell arrival signal for each identifier based on the identifier identified by the identification unit. A circuit and a ring counter, in a range of the count value A to the count value B, returning to A when the count value reaches B, or returning to B when the count value reaches A. A ring counter that periodically counts, and a counter value storage unit that is connected to the ring counter and stores a ring counter value at the time when a cell immediately before the input cell and a cell having the same identifier is input. An address generation unit connected to the identification unit and configured to generate an address at which a ring counter value at the time when the immediately preceding cell for each identifier is input is stored; Is connected to the data value storage unit and the ring counter, and calculates the difference between the value of the ring counter at the time when the cell is input and the value of the ring counter at the time when the cell with the immediately preceding and the same identifier is input. A calculation unit to
A peak cell interval storing a value obtained by adding a cell delay variation allowable value to a peak cell interval which is a reciprocal of a maximum value (peak cell rate) of a traffic amount agreed in advance for each identifier between an ATM user and a communication carrier. A storage unit, which is connected to the calculation unit and the peak cell interval storage unit, and compares a difference value calculated by the calculation unit with a peak cell interval obtained by adding a cell delay variation allowable value stored in the peak cell interval storage unit; A comparing and judging unit, which is connected to the identifier separating unit,
A cell delay unit for temporarily holding an input cell, connected to the cell delay unit and the comparison and determination unit, and based on the determination result of the comparison and determination unit, passing or discarding the cell, or signing the cell And a cell control unit for performing a process of adding Furthermore, the identifier is a virtual path identifier VPI for identifying whether or not to use the virtual path VP. Further, the identifier is a virtual channel identifier VCI for identifying which virtual channel in the virtual path VP should be used to send data to the other party.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the UPC circuit according to the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing the configuration of this embodiment. In the figure, 101 is V
VPI information separation unit for separating PI information, 121 to 12
N is a VPI identification unit 1 to N for identifying a VPI, 103 is an OR gate that receives outputs from the VPI identification units 121 to 12N, and outputs a logical sum of them, and 104 is a ring that receives a cell arrival signal from the OR gate 103. A counter that counts periodically with a constant count width, such as returning to A when the counter value reaches B or returning to B when the counter value reaches A in the range from value A to value B. Is what you do. Reference numeral 105 denotes a counter value storage unit,
06 is an address generation unit, 107 is a calculation unit, 108 is a peak cell interval storage unit (a value obtained by adding a cell delay variation allowable value), 109 is a comparison determination unit, 110 is a cell delay unit, 11
1 is a cell control unit. The operation of the present embodiment configured as described above is as follows. The cell transmitted from each user of the ATM is separated from the cell part and the virtual path identifier VPI by the VPI information separation unit 101, and the separated VPI is VP
The cells are transmitted to the I identification sections 121 to 12N, and the cell section is transmitted to the cell delay section 110. VPI identification units 121 to 12
In N, each VPI is identified. As a result of the identification, if an arbitrary VPI matches a VPI value unique to each VPI identification unit, a cell arrival signal is sent to the OR gate 103.
On the other hand, the VPI information is also sent to the address generation unit 106. Then, the cell arrival signals from the VPI identifiers 121 to 12N are ORed by the OR gate and sent to the ring counter 104 and the counter value storage unit 105.

The address generation unit 106 generates those addresses in the counter value storage unit 105 according to the VPI, and sends them to the counter value storage unit 105. The counter value at the time when the cell arrival is notified from the OR gate 103 is output from the ring counter 104, and at the same time, the counter value stored in the output address of the address generation unit 106 is output from the counter value storage unit 105. Calculation unit 1
At 07, the difference between the counter value of the output of the ring counter 104 and the counter value of the output of the counter value storage unit 105 is calculated, and the difference is sent to the comparison determination unit 109. In the comparison determination unit 109, the difference value output from the calculation unit 107 is compared with the output of the peak cell interval storage unit 108. If the difference value is larger than the peak cell interval, it is held in the cell delay unit 110. The cell unit is determined to be normal, and the cell unit held in the cell delay unit 110 via the cell control unit 111 is allowed to pass as a normal cell. If the difference value is smaller than the peak cell interval, the comparison determination unit 109 determines that the cell is abnormal, prohibits passage through the cell unit held in the cell delay unit 110, and discards the cell.

The above calculation in the calculation unit 107 is performed as follows. 1) The arrival of the cell is determined based on the notification from the VPI identification units 121 to 12N, and the counter value S when the cell Q arrives is read from the ring counter 104 based on the determination. 2) The counter value s when the cell Q with VPI = N arrives is temporarily stored in the memory of the counter value storage unit 105. 3) V separated by the VPI identification units 121 to 12N
The arrival of the cell R next to the cell Q of PI = N is determined by the VPI identification unit 1
The counter value t when the cell R arrives is read from the ring counter 104 based on the notification. 4) Next, the counter value s when the cell Q of VPI = N arrives
And the counter value t at the arrival of the cell R with VPI = N is usually calculated by subtracting a small value from a large value. Also, the ring counter 104
(Where A = 0 <B), s + (B−t) is calculated. Further, when the ring counter 104 passes the B and returns to the A (where A = 0 <B), t + (B−s) is calculated. 5) If this calculation result is smaller than the peak cell interval stored in the peak cell interval storage unit 108, VPI =
It is determined that the flow rate of the cell N is a violation, and a violation signal is output. Further, when the calculation result is larger than the peak cell interval stored in the peak cell interval storage unit 108, the VPI
= N is determined to be normal. 6) Perform the above operation for each VPI. In the embodiment described above, VPI (Virtual) is used.
Path Identifier) using virtual path V
Although the case where the present invention is applied when discriminating whether or not to use P has been described, the present invention is not limited to the above-described embodiment, and the present invention is not limited to the above-described embodiment.
The present invention can also be applied to the case where it is necessary to identify which virtual channel in the virtual path VP should be used to send data to the other party by using (l Identifier).

[0009]

As described above, according to the present invention, in the conventional UPC circuit using the leaky bucket method, the ring counter for counting the cell arrival signal and the cell immediately before the input cell are the same. A counter value storage unit that stores a ring counter value when a cell having a VPI is input, and an address generation unit that generates an address at which a ring counter value is stored when a immediately preceding cell is input for each VPI. A calculation unit for calculating the difference between the value of the ring counter at the time when a cell is input and the value of the ring counter at the time when a cell having the same and the same VPI is input, and the reciprocal of the maximum value of the traffic volume A peak cell interval storage unit that stores a value obtained by adding a cell delay variation allowable value to a peak cell interval, and a peak obtained by adding the difference value of the calculation unit and the cell delay variation allowable value. By providing a comparison section for comparing the Le interval, as in the prior art policing unit VP
The cell can be monitored without having to configure each I, and the amount of hardware can be reduced, the circuit configuration can be simplified, and the cost can be reduced.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of an embodiment of a UPC circuit according to the present invention.

FIG. 2 is a block diagram showing a conventional UPC circuit.

[Explanation of symbols]

101 VPI information separation unit, 103 OR gate, 10
4 ring counter, 105 counter value storage unit, 10
6 address generation unit, 107 calculation unit, 108 peak cell interval storage unit, 109 comparison determination unit, 110 cell delay unit, 111 cell control unit, 121 to 12N VPI identification unit, 201 VPI information separation unit, 205 OR gate, 206 cell delay Unit, 207 Cell control unit, 221
To 23N VPI identification unit, 231 to 23N cell monitoring unit, 241 to 24N policing unit, 301 counting unit, 302 comparison judgment unit, 303 peak cell rate storage unit, 304 allowable cell delay variation storage unit

Claims (3)

[Claims] 1. A UPC circuit for monitoring and controlling the flow rate of cells by counting intervals between cells arriving successively, which is defined by an arbitrary identifier, and separates input cell identifiers for each cell. And a plurality of identification units connected to the identifier separation unit for identifying the separated identifiers, and a cell arrival signal for each of the identifiers connected to these identification units based on the identifiers identified by the identification units. An OR circuit for outputting, a ring counter for periodically counting with a fixed count width, connected to the ring counter,
A counter value storage unit that stores a ring counter value at the time when a cell having the same identifier as the cell immediately before the input cell is input, and a counter value storage unit that is connected to the identification unit and receives the immediately preceding cell for each identifier. An address generation unit that generates an address at which a ring counter value is stored at a time point, which is connected to the counter value storage unit and the ring counter, and the value of the ring counter at the time when a cell is input and the value immediately before and A calculation unit that calculates the difference from the value of the ring counter when a cell with the same identifier is input, and adds the allowable value of the cell delay variation to the peak cell interval that is the reciprocal of the maximum value of the traffic volume (peak cell rate). A peak cell interval storage unit that stores the calculated value, connected to the calculation unit and the peak cell interval storage unit, and stores the difference value calculated by the calculation unit and the peak cell interval storage unit. A comparison / determination unit for comparing a peak cell interval obtained by adding a permissible cell delay variation allowable value; a cell delay unit connected to the identifier separation unit for temporarily holding an input cell; And a cell control unit connected to the comparison determination unit and performing a process of passing or discarding a cell or adding a code to a cell based on the determination result of the comparison determination unit.
C circuit. 2. The UPC circuit according to claim 1, wherein said identifier is a virtual path identifier VPI for identifying whether or not to use a virtual path VP. 3. The UPC according to claim 1, wherein the identifier is a virtual channel identifier VCI for identifying which virtual channel in the virtual path VP should be used to send data to the other party. circuit.