JPH0879251A - Circuit and method for controlling cell traffic - Google Patents

Abstract

PURPOSE: To provide a circuit and a method for controlling cell traffic capable of coping with a small hardware amount even when the number of band management objects is increased by providing a means for counting the number of frames during transfer on a line and a buffer for storing cells constituting the frames and controlling the cell traffic on an output line so as to be within a stipulated value. CONSTITUTION: The numbers of the frames during the transfer for respective virtual channels(VCs) and as a whole are observed in a traffic observation part 16. Then, when the new frame arrives, whether or not the number of the entire frames during the transfer exceeds a maximum frame number N transferrable on the line and whether or not the number of the frames during the transfer of the VC exceeds a frame number M transferrable in a band stipulated beforehand are observed. Then, in the case of exceeding the stipulated value, an exceeding part is stored in a frame buffer part 14 by a frame transfer control part 13. In such a manner, the traffic is smoothed and the band is controlled for the respective VCs.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cell traffic control circuit and method, and more particularly to a device for dividing an information frame into cells shorter than the length of the information frame or transferring the cells or relaying, multiplexing or exchanging cells. TECHNICAL FIELD The present invention relates to a cell traffic control circuit and method for frame transfer in a system that performs the above.

[0002]

As is well known, an asynchronous transfer mode (As
ynchronous Transfer Mode:
In a communication network using ATM, information to be communicated is divided into fixed-length cells and transferred, so that media having different communication bit rates can be handled in a unified manner.

Here, the used band of each communication is controlled by the number of cells to be transferred, and the band can be changed temporally in the same communication. In addition, like data communication, a communication mode in which information is not always transferred even if a communication channel is set up and cells are transferred in bursts only when there is data to be transmitted can be considered.

In such a communication network, the communication quality can be guaranteed by predefining a band used by each communication channel and allocating an intra-network resource matching the specified band.

In the ATM network, these communication bands are usually managed for each virtual path (VP) or virtual channel (VC). Therefore, on the information transmitting side, it is necessary to control so that the amount of transmitted information does not exceed the specified value for each band management unit such as VP and VC.

FIG. 6 shows a basic configuration of a cell traffic control circuit when there are a plurality of communication channels using the conventional technique. The cell traffic control circuit shown in FIG.
2, multiplex unit 63, FIFO queue 6 for each band management unit
4. The read control unit 65.

Here, a case where the band management unit is VC will be described. VC is VPI written in the cell header
It is identified by the value of (virtual path identifier) / VCI (virtual channel identifier).

The cell arriving from the input line 61 reads the VPI / VCI value written in the header in the distribution unit 62 and loads it in the FIFO queue 64 corresponding to the VPI / VCI value.

In the read control unit 65, each VPI / VCI
The reading from each FIFO queue is controlled corresponding to a band defined in advance. For example, the output line speed is 15
In the case of 0 Mbit / s, if the specified band of a certain VC is 1.5 Mbit / s, only 1 cell is sent in 100 cell sending time, and if 3.0 Mbit / s, 1 is sent in 50 cell sending time. FIFO of the relevant VPI / VCI only for cells
It may be controlled so that the cell is read from the queue. The read cells from the respective FIFO queues thus controlled are multiplexed by the multiplexer 63 and sent to the output line 66.

[0010]

However, in this cell traffic control system according to the prior art, since the FIFO queues are installed by the number of band management units, the amount of hardware increases as the number of channels subject to band management increases. .

For example, 64 on a line of 150 Mbit / s
When kbit / s communication channels are multiplexed, the number of band management units is 2000 or more. In the present invention, in order to solve this problem, a cell traffic control circuit capable of realizing traffic control capable of handling with a small amount of hardware even if the number of bandwidth management targets is large, without installing a FIFO queue for each bandwidth management unit, and The purpose is to provide a method.

[0012]

According to the present invention, in order to solve the above problems, an information frame to be communicated is divided into a plurality of cells having a fixed length, or transferred as a single cell on a line of a predetermined speed. And in a cell traffic control method for controlling cell traffic on the line, which is used for a frame transfer method in which a plurality of information frames are simultaneously transferred on the same line, Means for defining the maximum number of frames N that can be transferred at the same time and counting the number of frames n being transferred on the line, and a cell that constitutes the frame when the number of input frames exceeds the specified maximum number of frames. At the time of cell arrival, if the arriving cell is a valid cell and is the first cell or a single cell forming the information frame, <In the case of N transfers a series of cells belonging to the same frame and the cell on the output line, n =
In the case of N, a cell belonging to the same frame as the cell is accumulated in the buffer while identifying the frame, and the input cell of the frame accumulated in the buffer is an invalid cell such as an empty cell or When the cells are stored in the buffer and the cells are not transferred on the output line, the cell traffic on the output line is read out by a specified value by reading from the buffer in the range of n ≦ N and transferring the cells on the line. There is provided a traffic control method characterized by being controlled within.

Further, according to the present invention, in the above-mentioned cell traffic control method, when reading cells from the buffer onto the output line, control is performed so that cells belonging to the same frame are read at a predetermined interval. A cell traffic control method is provided.

Further, according to the present invention, in the above-mentioned cell traffic control method, a bandwidth management unit for controlling traffic on the line is set, and the maximum number of frames N capable of simultaneously transferring the traffic transferable on the line N Then, the maximum number M of simultaneously transferable traffic that can be transferred on the line for each bandwidth management unit w belongs to the same management unit.
(W), the total number of frames in transit on the line n
And a means for counting the number of frames m (w) being transferred on the line for each band management unit, and when the arriving cell is a valid cell and is the head cell or a single cell forming the information frame, the cell N <N at the time of arrival and m (w) <
In the case of M (w), a series of cells belonging to the same frame as the cell is transferred onto the output line, and in the case of n = N or m (w) = M (w), the same as the cell. A series of cells belonging to a frame is stored in the buffer while identifying the frame, and for the frame stored in the buffer, the input cell is an invalid cell such as an empty cell, or the input cell is stored in the buffer and stored. N ≦ N and m (w) ≦ M if no cells are transferred on the output line
A cell traffic control method is provided, wherein the traffic on the output line is controlled within a prescribed value by reading from the buffer and transferring it onto the line within the range of (w).

Further, according to the present invention, in order to solve the above problems, an information frame to be communicated is divided into a plurality of cells of fixed length, or transferred as a single cell on a line of a predetermined speed, and In a frame transfer method in which a plurality of information frames are simultaneously transferred on the same line, a cell detection unit that detects the arrival of cells on the line, the type of the arriving cell, and the frame identifier displayed in the cell, The total number n of frames being transferred on the output line and the number m (w) of frames being transferred on the line for each bandwidth management unit w
A traffic observing section for counting the number of frames, a frame buffer section comprising a plurality of frame buffers for accumulating cells constituting the frame in frame units when the frame exceeds the specified maximum number of frames, and the frame buffer section. And a frame transfer control unit that determines whether an incoming cell is stored in the frame buffer unit or transferred to the output line. Has a frame-accumulation registration table that holds the value of the band management unit w in which the frame being stored in the frame buffer unit exists, and the band management unit to which the arrival cell detected by the cell detection unit belongs is the frame. If the cell is being registered in the accumulation register table, the cell is accumulated in the frame buffer unit. If the arriving cell is an intermediate cell or an end cell constituting an information frame when not registered, the cell is transferred to the output line, and if the head cell or a single cell, the cell is output by the predetermined determination method. A cell traffic control circuit is provided which determines whether to transfer to a line or store in a frame buffer.

Further, according to the present invention, in the above-mentioned cell traffic control circuit, the frame-accumulation registration table in the frame transfer control unit is a bandwidth management unit w in which a frame being accumulated in the frame buffer unit exists. With the value, the first accumulated frame buffer number is the first accumulated frame buffer number among the accumulated frames belonging to the band management unit, and the frame buffer number in which the latest accumulated frame is accumulated is the latest accumulated frame buffer. When the arrival cell detected by the cell detection unit is a head cell or a single cell forming an information frame, the band management unit to which the cell belongs is stored in the frame accumulation registration table. When it is judged that the frame is not being registered and the frame buffer will be stored Hunt an empty frame buffer number from the empty frame buffer section, write the cell on the frame buffer surface of the frame buffer section having the frame buffer number, and set the frame buffer number to the first accumulated frame buffer number and the latest frame buffer number. With the value of bandwidth management unit w,
If the bandwidth management unit to which the cell belongs is being registered in the frame-accumulation registration table, the empty frame buffer number is hunted from the empty frame buffer section and the corresponding frame buffer number is registered. While writing the cell on the frame buffer surface of the frame buffer unit having the, the latest frame buffer number of the band management unit of the frame accumulation registration table is newly rewritten to the hunted frame buffer number from the empty frame buffer management unit. A cell traffic control circuit is provided which manages a frame buffer surface in which frames belonging to the same bandwidth management unit are accumulated in the frame buffer unit in the accumulation order of the frame buffer.

Further, according to the present invention, in the above-mentioned cell traffic control circuit, the frame transfer control unit has a reading buffer number register for registering a frame buffer number being read from the frame buffer unit,
Similarly, a display flag indicating whether or not a frame belonging to the band management unit being registered is being read is stored in the frame accumulation registration table in the frame transfer control unit, and the arrival cell detected by the cell detection unit is invalid. If a cell or an arriving cell is stored in the frame buffer unit and the cell is not transferred to the output line, 1 from the frame buffer surface in the frame buffer unit having the number held in the reading buffer number register. When the cell is read and transferred to the output line, or when the frame buffer number is not registered in the read buffer number register, n≤N-1 and m (w) ≤M-1 and the value of the read display flag is read. If the bandwidth management unit w indicating that the frame is not being registered is registered in the frame accumulation registration table, The value of the first accumulated frame buffer number recorded in the table is read, the value is registered in the read buffer number register, and one cell is read from the buffer surface in the frame buffer part of the frame buffer number and transferred to the output line. At the same time, when the read cell is the last cell or a single cell forming the information frame, the next frame buffer number belonging to the same band management unit is read from the frame buffer unit and the value of the reading buffer number register is rewritten,
A cell characterized by deleting the band management unit from the reading buffer number register and the frame storage registration table when other frames belonging to the same band management unit are not stored in the frame buffer unit. A traffic control circuit is provided.

[0018]

According to the above-mentioned solving means, in the present invention, the traffic observing section observes the number of frames being transferred for each virtual channel (VC) and the total number of frames being transferred, and when a new frame arrives, the number of frames being transferred is determined as The maximum number N of frames that can be transferred on the line is exceeded, or the number of frames being transferred by the VC is the number M of frames that can be transferred in a predetermined band.
The band transfer control unit controls the band for each VC by accumulating in the frame buffer unit and smoothing the traffic with respect to the portion exceeding.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS First, the outline of the present invention will be described. The present invention is intended for data communication in which an information frame is divided into cells and transferred. As shown in FIG. 7, a group of cells forming an information frame is generally composed of a head cell BOM, some intermediate cells COM, and an end cell EOM. Successive cells in the same frame are the transmission rate V of the communication channel.
The data is transferred with an interval T corresponding to 0. Even if the information frame length is short and the information frame is made into a cell, the frame may be composed of one cell, and this cell is called a single cell SSM.

When cells of a cell transfer rate V0 are transferred into cells on a line of speed V (V> V0), the cell interval T is V / V0 cell time (one cell time is on the line of the speed concerned). Equivalent to the time required to transfer one cell).

On a line of speed V, a maximum of N frames (N = V / V0) can be multiplexed and transferred simultaneously. In a system handling such communication, when n frames are being transferred at the same time, the in-use band can be calculated by n × V0.

That is, as shown in FIG. 8, n cells are transferred within the time T. Therefore, in order to control cell-level traffic, the number of frames in transfer n (N ≧ n
It is sufficient to control ≧ 0).

Therefore, in the present invention, the traffic observing unit observes the number of frames being transferred for each VC and the entire frame, and when a new frame arrives, the total number of frames being transferred is the maximum number N of frames that can be transferred on the line. If it exceeds or the number of frames being transferred of the VC exceeds the number of frames M (VCI) that can be transferred in a predetermined band, the band is accumulated for each VC in the frame buffer to smooth the traffic, and thus the band is set for each VC. Control.

Next, embodiments of the present invention based on the above outline will be described in detail with reference to the drawings. FIG. 1 shows the configuration of a cell traffic control circuit as an embodiment for realizing the cell traffic control system of the present invention.

The cell traffic control circuit of this embodiment is shown in FIG.
As shown in FIG. 1, the cell detection unit 12 and the frame transfer control unit 1
3, a frame buffer unit 14, an empty frame buffer management unit 15, and a traffic observation unit 16.

In FIG. 1, the cell detection unit 12 identifies the function of detecting the arrival of a cell on the input line 11 and the type of the detected cell. This cell detector 12 converts the information frame into the ITU-T standard I.S. Taking as an example the case where cells are made into cells using the ATM adaptation layer type 3 defined by 362 and 363, the cell type is identified by the ST field in the cell.

Here, in the ST field, the first cell (B
OM), intermediate cell (COM), final cell (EOM), or single cell (SSM) can be identified, and multiple frames on the same VCI can be multiplexed in a cell by a multiplex identifier (MID). Yes, VPI / VC in cell
Individual frames can be identified by the value of the I / MID field.

A value such as VPI / VCI / MID that can identify each frame is also called a frame identifier. In this embodiment, the bandwidth management unit is VPI / V
It is a virtual channel (VC) that can be identified by the CI value, and it is assumed that a plurality of frames with different MIDs can be multiplexed and transferred on the same VC.

When the cell detector 12 detects the arrival of a cell, the cell arrival display signal, the cell type signal,
The frame identifier is sent to the frame transfer control unit 13. At this time, the cell detection unit 12 displays an empty cell as a cell arrival display when the arrived cell is an empty cell (invalid cell).

Further, the frame transfer control unit 13 has a prescribed bandwidth table 13a, a frame accumulation registration table 13b,
It has a reading buffer number register 13c and controls transfer in frame units and storage in the buffer.

Here, the frame accumulation registration table 13
In b, an identifier of a band management unit in which frames are being stored in the frame buffer unit 14 (VPI / V in this embodiment)
CI), the frame buffer number being written, and a reading-in-progress indication indicating whether the reading of the frame being accumulated in the frame buffer unit 14 has been started.
F, ON is held.

The processing operation of the frame transfer controller 13 will be described later. FIG. 2 shows a detailed structure of the frame buffer unit 14. The frame buffer unit 14 includes a plurality of (j frames in the figure) frame buffers (# 1, # 2, ..., #j), next frame buffer number registers R1, R2 ,. 14a.

Here, each frame buffer # 1, # 2,
, #J are cells that compose the same frame as BOM, CO
The cells are held in the order of arrival of M, ..., EOM, and the cells are also read in this order at the time of reading.

Then, the write instruction from the frame transfer control unit 13 to the frame buffer unit 14 includes a VPI / VCI / MID value, a cell type, and a previous frame buffer number Buf. No, frame buffer number Buf. No. With new and continuous accumulation display.

As a result, when receiving a write instruction from the frame control unit 13, the frame buffer unit 14 causes the VPI / V in the parameter when the cell type is COM or EOM.
The in-writing frame registration table 14a is searched based on the CI / MID value, the frame buffer number corresponding to the VPI / VCI / MID value is read, and the frame buffers # 1, # 2, ... Write a cell.

When the cell type is COM, after writing the cells in the frame buffers # 1, # 2, ..., #j, the VPI is written from the in-writing frame registration table 14a.
Delete the / VCI / MID value.

When the cell type is BOM or SSM and the continuous accumulation display is OFF, the frame buffer number Buf. No. The VPI / VCI / MID together with the new are registered in the frame-in-writing registration table 14a, and the frame buffer number Buf. No. The cell is written into the new frame buffer (in the case of SSM, VPI / VCI / MID is not registered in the frame registration table during writing).

In this case, the frame buffer number Bu
f. No. Next frame buffer number register R of new
A value representing the "final frame" is written in 1, R2, ..., Rj.

On the other hand, when the cell type is BOM or SSM and the continuous accumulation display is ON, the continuous accumulation display is OF.
As in the case of F, the frame buffer number Buf. No. VPI / VCI / in conjunction with new
The MID is registered in the in-writing frame registration table 14a, the cells are written in the frame buffers # 1, # 2, ..., #j of the frame buffer number, and the cell frame buffer number Buf. No. As a next frame buffer number of new, a value representing "final frame" is written in the next frame buffer number registers R1, R2, ..., Rj, and the previous frame buffer number Buf. No
Next frame buffer number register R1, R corresponding to
2, ..., Rj to the frame buffer number Buf. N
o. Write new (in the case of SSM, VPI / VCI / MID is not registered in the frame-in-writing registration table).

The read instruction from the frame control unit 13 to the frame buffer unit 14 is the frame buffer number Buf. With No (r).
As a result, when receiving a read instruction from the frame transfer control unit 13, the frame buffer unit 14 causes the frame buffer number Buf. No (r) frame buffer #
1, # 2, ..., #j, one cell is read, and the type of cell being read and the frame buffer number Buf. , Rj corresponding to the No (r) frame buffers # 1, # 2, ..., #j are returned to the frame transfer control unit 13.

When the type of the read cell is EOM or SSM, the frame buffer section 14 reads the frame buffer number Buf. No
(R) is sent to the empty frame buffer management unit 15 as an empty buffer and registered as an empty frame buffer.

The empty frame buffer management unit 15 registers the frame buffer number received from the frame buffer unit 14 as an empty frame buffer number in order to manage the empty frame buffer in the frame buffer unit 14, and the frame transfer control unit 13 The frame buffer number to be used next to.

In FIG. 1, the traffic observing section 16 measures the number of frames being transferred for the whole and for each VPI / VCI value. Here, as shown in FIG. 3, the number of frames is measured by +1 when the head cell BOM or the single cell SSM belonging to the VPI / VCI is transferred, and the cell interval T after the last cell or the single cell is transferred. It can be realized by installing a counter that decrements by -1 after each VPI / VCI.

Regarding the measurement of the number of frames, Japanese Patent Application No. 6-38873 "Traffic measuring method and its circuit"
The means described in can be used. Hereinafter, the operation of the frame transfer control unit 13 will be described with reference to the operation flow at the time of cell arrival shown in FIG. 4 and the operation flow at the time of buffer reading shown in FIG.

First, the cell arrival indication from the cell detector 12, cell type, frame identifier (VPI / VCI / MI
Upon receiving D), the frame transfer control unit 13 starts the cell arrival process shown in FIG.

The cell type is CO instead of BOM or SSM.
If it is M or EOM, the frame buffer storage registration table 13b is searched for whether the VPI / VCI is being registered, and if it is being registered, the cell is transferred to the frame buffer unit 14. Together with VPI / V as a parameter value for the frame buffer unit 14.
A write instruction is issued together with the CI / MID value and cell type (steps S1, S2, S3).

In this case, the previous frame buffer number Buf. No, frame buffer number Buf. No. New and continuous accumulation display are not used. On the other hand, when the VPI / VCI is not registered in the frame buffer accumulation registration table 13b, the cell is transferred to the output line 17 (step S4).

On the other hand, when the arriving cell is BOM or SSM, it is searched whether or not the VPI / VCI is being registered in the frame buffer accumulation registration table 13b.
If it is being registered, the frame accumulation registration table 13
b to the latest frame buffer Buf. No. is read out and a new empty frame buffer number Buf. No. Hunt new (steps S1, S5, S6, S7).

Thereafter, the cell concerned is transferred to the frame buffer unit 1.
4 to the frame buffer unit 14, and the VPI / VCI / MID value, cell type, previous frame buffer number Buf. No, frame buffer number Buf. No. new, continuous accumulation display ON
At the same time, a write instruction is given (step S8).

After the write instruction to the frame buffer unit 14 is completed, the frame buffer number of the relevant VPI / VCI in the frame accumulation registration table 13b is newly hunted to the frame buffer number Buf. No. It is rewritten to new (step S9).

On the other hand, when the VPI / VCI is not registered in the frame buffer accumulation registration table 13b, the entire traffic measurement value is (N-1) based on the measurement value in the traffic observation section 16. The following (N is the maximum number of frames that can be transferred simultaneously on the output line), and the V
The measured traffic value of PI / VCI is (M (VPI / VC
I) -1) or less (M (VPI / VCI), VP
It is determined whether or not it is less than or equal to the maximum number of frames that can be simultaneously transferred in the specified band corresponding to the I / VCI value.
In this case, the cell is transferred to the output line 17 (steps S10 and S4).

If the determination result is No, the empty frame buffer management unit 15 determines that the frame buffer number B
uf. No. Hunt new, transfer the cell to the frame buffer unit 14, and send VPI / VCI / M to the frame buffer unit 14 as a parameter value.
ID value, cell type, frame buffer number Buf. N
o. A write instruction is given together with new and continuous accumulation display OFF, and the VPI / VCI value is registered in the frame accumulation registration table 13b.

At this time, the frame accumulation registration table 13
In the other column of b, the first frame buffer number and the latest frame buffer number Buf. No. New, display during reading = OFF.

Next, when the cell arrival indication received from the cell detection unit 12 is an empty cell indication (no valid cell arrives), or in the arrival cell processing flow of FIG. The frame buffer unit 14 without transferring
When it is transferred to the frame buffer 14 shown in FIG.
The reading process from is started.

Here, the frame transfer control unit 13 manages the frame being read by the reading buffer number register 13c, and further manages which frame of the next cell is read by the next read register number.

First, the next read register number at the time when the frame transfer control unit 13 starts the read process from the frame buffer unit 14 is set to r (step S2).
1). Here, if the read-out buffer number register 13c of the number r is read out as an empty block, and the display is "closed", the following processing 3 is performed (step S22).

(Processing 3) Frame buffer number Buf. No (r) is read and the parameter Buf. A read instruction is issued together with No (r) (steps S23 and S24).

When the frame buffer section 14 receives a read instruction, it returns the type of the cell being read and the next frame buffer number. If the cell type is EOM or SSM, and the next frame buffer number is "final frame". If not, the value of the frame buffer number of the reading buffer number register 13c of the register number r is rewritten to the next frame buffer number received from the frame buffer unit 14, the next read register number is updated to r + 1, and the process ends. Yes (step S25-
S28).

If the next frame buffer number is the "final frame" in step S26, the VPI / V
The CI is deleted from the frame accumulation registration table 14a, the empty / occluded display of the reading buffer number register 13c is rewritten to "empty", and the processing 1 described later is performed (steps S29 and S30). (Processing 3 is completed up to this point) If the cell type is not EOM or SSM in step S25, the process proceeds to step S28, the next read register number is updated to r + 1, and the process ends.

When the frame transfer control unit 13 starts the reading process from the frame buffer unit 14 and the empty / occluded display of the reading buffer number register 13c corresponding to the next reading register number r is "empty", First,
The entire traffic measurement value (the number of frames being transferred) in the traffic observation unit is checked, and if the measurement value is (N-1) or less, the process 1 described below is performed, but if it is N or more, the next reading is performed. After updating the register number to r + 1, a new next read register number r '(= r
+1) based on the reading buffer number register 13c
The empty block display value is read and the process proceeds (step S3).
1, S32).

(Processing 1) Here, first, the VPI / display-off VPI / in the frame accumulation registration table 13b is turned off.
Whether or not the VCI is registered is searched, and if it is not registered, the next read register number is updated to r + 1 and the process is terminated (steps S33, S28).

When there is registration, the VPI / VCI traffic measurement value is (M (VPI / VCI) -1) or less based on the measurement value of the traffic observation unit 16 The VPI / VCI of OFF is searched, the frame buffer number of the corresponding VPI / VCI is read, and this value is read out buffer number register 1
3c is written as the frame buffer number, the empty block display (r) is set to “closed”, and the reading display of the VPI / VCI of the frame accumulation registration table 13b is rewritten to ON (steps S33 to S36).

After that, the processing 3 after step S23 described above is carried out. By using the above-described cell traffic control system of the present invention, it is possible to control the transfer traffic within a band defined in advance for each band management unit such as VP and VC.

Further, in the cell traffic control system of the present invention, it is possible to manage the bandwidth of several hundred to several thousand multiple communication channels without installing an individual FIFO buffer for each bandwidth management unit.

Further, in the cell traffic control system of the present invention, the input cell is transferred directly onto the output line without being stored in the buffer within a range not exceeding the specified band, so that the transfer delay time can be suppressed to a small value. .

[0066]

As described above, according to the present invention, therefore, a FIFO queue is not installed for each band management unit,
It is possible to provide a cell traffic control circuit and method capable of realizing traffic control with a small amount of hardware even if the number of band management targets increases.

[Brief description of drawings]

FIG. 1 is a diagram showing a circuit configuration of an embodiment for realizing a cell traffic control system of the present invention.

FIG. 2 is a diagram showing a configuration example of a frame buffer unit in the cell traffic control circuit of the present invention.

FIG. 3 is a diagram showing a frame number counting method in a traffic observation unit.

FIG. 4 is a diagram showing an operation (arrival cell processing) flow of a frame transfer control unit.

FIG. 5 is a diagram showing an operation (frame buffer reading process) flow of a frame transfer control unit.

FIG. 6 is a diagram showing a configuration of a cell traffic control circuit according to a conventional technique.

FIG. 7 is a diagram showing an example in which an information frame is disassembled into cells and transferred.

FIG. 8 is a diagram showing an example in which information frames divided into cells are multiplexed and transmitted on a line.

[Description of Codes] 11 ... Input line, 12 ... Cell detection unit, 13 ... Frame transfer control unit, 14 ... Frame buffer unit, 15 ... Free frame buffer management unit, 16 ... Traffic observation unit, 13a
... Specified bandwidth table, 13b ... Frame accumulation registration table, 13c ... Reading buffer number register, 14a
... Writing frame registration table, # 1, # 2, ..., #
j ... Frame buffer, R1, R2, ... Rj ... Next frame buffer number register.

Claims (6)

[Claims] 1. An information frame to be communicated is divided into a plurality of cells having a fixed length, or transferred as a single cell on a line of a predetermined speed, and a plurality of information frames are simultaneously multiplexed on the same line. In a cell traffic control method used for a frame transfer method for controlling transfer of cell traffic on the line, the traffic that can be transferred on the line is defined by the maximum number N of frames that can be transferred at the same time. The arriving cell is a valid cell, and has means for counting the number of frames n being transferred, and a buffer for accumulating cells constituting the frame when the number of frames input exceeds the specified maximum number of frames. Yes n at the time of cell arrival when the cell is the first cell or a single cell that constitutes the information frame
When <N, a series of cells belonging to the same frame as the cell is transferred to the output line, and when n = N, a series of cells belonging to the same frame as the cell is identified and the buffer In the frame accumulated in the buffer and the input cell is an invalid cell such as an empty cell, or when the input cell is accumulated in the buffer and the cell is not transferred to the output line, n ≦ A cell traffic control method, wherein the cell traffic on the output line is controlled within a specified value by reading from the buffer in the range of N and transferring to the line. 2. The cell traffic control method according to claim 1, wherein when cells are read from the buffer onto the output line, cells belonging to the same frame are controlled to be read at a predetermined interval. Cell traffic control method. 3. The cell traffic control method according to claim 1, wherein a bandwidth management unit for controlling traffic on the line is set, and the maximum number of frames at which traffic that can be transferred on the line can be simultaneously transferred. N, the traffic that can be transferred on the line for each band management unit w is defined by the maximum number M (w) of frames that belong to the same band management unit that can be transferred at the same time, and the total number of frames being transferred on the line. n and a number m (w) of frames being transferred on the line for each band management unit are provided, and when the arriving cell is a valid cell and is the head cell or a single cell forming the information frame, N when the cell arrives
If <N and m (w) <M (w), transfer a series of cells belonging to the same frame as the cell on the output line, and n = N or m (w) = M (w). In the case of, a series of cells belonging to the same frame as the cell is accumulated in the buffer while identifying the frame, and for the frame accumulated in the buffer, the input cell is an invalid cell such as an empty cell, or If the input cells are stored in the buffer and the cells are not transferred on the output line, by reading from the buffer and transferring them on the line in the range of n ≦ N and m (w) ≦ M (w), A cell traffic control method comprising controlling cell traffic on the output line within a prescribed value. 4. An information frame to be communicated is divided into a plurality of fixed-length cells, or transferred as a single cell over a line of a predetermined speed, and a plurality of information frames are simultaneously transferred over the same line. In the frame transfer method described above, a cell detection unit that detects the arrival of cells on the line, the type of the arriving cell, and the frame identifier displayed in the cell, and the total number of frames n and the band being transferred on the output line. A traffic observation unit that counts the number of frames m (w) that are being transferred on the line for each management unit w, and when the number of frames exceeds the specified maximum number of frames, the cells that make up the frames are stored in frame units. And a frame buffer section for managing the empty frame buffer of the frame buffer section A frame transfer control unit that determines whether an incoming cell is stored in the frame buffer unit or is transferred to the output line, and the frame transfer control unit is configured to detect a frame being stored in the frame buffer unit. In the case where a band accumulation unit registration table holding the value of the existing band management unit w is stored, and the band management unit to which the arrival cell detected by the cell detection unit belongs is being registered in the frame accumulation unit registration table, The cell is stored in the frame buffer unit,
If the arriving cell is not registered, it is transferred to the output line if it is an intermediate cell or the last cell that constitutes an information frame, and if it is the first cell or a single cell, the cell is transferred to the output line by a predetermined judgment method A cell traffic control circuit characterized by deciding whether to transfer or store in a frame buffer. 5. The cell traffic control circuit according to claim 4, wherein the frame storage registration table in the frame transfer control unit is a value of a band management unit w in which a frame being stored in the frame buffer unit exists. At the same time, of the frames being accumulated that belong to the band management unit, the frame buffer number that was accumulated first is the first accumulated frame buffer number, and the frame buffer number that is the frame that has started accumulating most recently is the latest accumulated frame buffer number. When the arrival cell detected by the cell detection unit is a head cell or a single cell forming an information frame, the band management unit to which the cell belongs is registered in the frame accumulation registration table. If it is determined that the frame is not being stored and the frame buffer is to be stored, the free frame Hunts an empty frame buffer number from the frame buffer section, writes the cell on the frame buffer surface of the frame buffer section having the frame buffer number, and sets the frame buffer number as the first accumulated frame buffer number and the latest frame buffer number. When the bandwidth management unit to which the cell belongs is registered in the frame accumulation registration table together with the value of the management unit w, and the frame management unit to which the cell belongs is registered in the frame accumulation registration table And write the cell on the frame buffer surface of the frame buffer unit having the frame buffer number, and newly set the latest frame buffer number of the band management unit of the frame accumulation registration table to a new empty frame buffer management. Rewriting the frame buffer numbers and hunt from cell traffic control circuit, characterized in that managing the frame buffer surface which frame has been accumulated belonging to the same band management unit in the frame buffer in the storage order of the frame buffer. 6. The cell traffic control circuit according to claim 4, wherein the frame transfer control unit has a reading buffer number register for registering a frame buffer number being read from the frame buffer unit, The frame accumulation registration table in the transfer control unit holds a display flag indicating whether or not a frame belonging to the band management unit being registered is being read, and the arrival cell detected by the cell detection unit is an invalid cell. If there is, or if an arriving cell is stored in the frame buffer section and the cell is not transferred to the output line, one cell is read from the frame buffer surface in the frame buffer section having the number held in the reading buffer number register. To the output line or to the read buffer number register When the buffer number is not registered, n ≦ N−1 and m (w) ≦ M−1, and the value of the read display flag indicates that the bandwidth management unit w is registered during the frame accumulation. If it is registered in the table, the value of the first accumulated frame buffer number recorded in the table is read, the value is registered in the read buffer number register, and at the same time, one cell from the buffer surface in the frame buffer part of the frame buffer number is read. While reading and transferring to the output line, if the read cell is the last cell or a single cell forming the information frame, the next frame buffer number belonging to the same band management unit is read from the frame buffer unit and the reading is being performed. The value of the buffer number register is rewritten, and the same bandwidth Cell traffic control circuit, characterized in that deletes the bandwidth management unit from the buffer number register and the frame accumulation in the registration table in the reading when other frames belonging to the unit is not stored.