JP2988654B2 - Cell traffic control circuit and method - Google Patents

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 an apparatus for dividing an information frame into cells shorter than the cell length and transferring the divided frames, or a relay transfer, multiplexing or switching of a group of cells. The present invention relates to a cell traffic control circuit and a method for frame transfer in a system for performing frame transfer.

[0002]

2. Description of the Related Art As is well known, an asynchronous transfer mode (As
ynchronous Transfer Mode:
In a communication network using ATM, by dividing information to be communicated into fixed-length cells and transferring them, media having different communication bit rates can be handled uniformly.

[0003] Here, the band used for each communication is controlled by the number of cells to be transferred, and the band can be temporally changed in the same communication. Also, a communication mode in which information is not always transferred even when a communication channel is set and cell transfer is performed in bursts only when there is data to be sent, such as data communication, can be considered.

[0004] In such a communication network, the communication quality can be assured by preliminarily defining the band used by each communication channel and allocating resources within the network corresponding to the specified band.

In an 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 the transmission information amount so as not to 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 in the case where a plurality of communication channels using the prior art exist. The cell traffic control circuit of FIG.
2. Multiplexer 63, FIFO queue 6 for each bandwidth management unit
4. It is composed of a reading control unit 65.

Here, a case where the bandwidth management unit is VC will be described. VC is the VPI written in the cell header
(Virtual path identifier) / VCI (virtual channel identifier).

The cell arriving from the input line 61 reads out the VPI / VCI value written in the header in the distribution unit 62, and is loaded into a FIFO queue 64 corresponding to the VPI / VCI value.

The read control unit 65 controls each VPI / VCI
The reading from each FIFO queue is controlled in accordance with a band specified in advance every time. For example, if the output line speed is 15
In the case of 0 Mbit / s, if the specified bandwidth of a certain VC is 1.5 Mbit / s, only one cell is transmitted for 100 cells, and if the specified band is 3.0 Mbit / s, one cell is transmitted for 50 cells. Only the cell is the FIFO of the VPI / VCI
What is necessary is just to control to read a cell from a queue. The read cells from the FIFO queues controlled in this way are multiplexed by the multiplexing unit 63 and transmitted to the output line 66.

[0010]

However, in the cell traffic control system according to the prior art, since FIFO queues are set for the number of band management units, if the number of channels to be band-managed is large, the amount of hardware increases accordingly. .

For example, 64 lines on a 150 Mbit / s line
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 coping with a small amount of hardware even when the number of band management targets is large without installing a FIFO queue for each band management unit and The aim is to provide a method.

[0012]

According to the present invention, in order to solve the above-mentioned problems, 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. Used in a frame transfer method in which a plurality of information frames are multiplexed and transferred on the same line at the same time, and in a cell traffic control method for controlling cell traffic on the line, traffic that can be transferred on the line is Means for counting the number n of frames being transferred on the line, defined by the maximum number N of frames that can be transferred simultaneously, and a cell constituting the frame when a frame is input exceeding the specified maximum number of frames If the arriving cell is a valid cell and is the first cell or a single cell constituting an 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 stored in the buffer while identifying the frame, and for the frame stored in the buffer, whether the input cell is an invalid cell such as an empty cell, or When cells are stored in the buffer and the cell is not transferred on the output line, the cell traffic on the output line is set to a specified value by reading out from the buffer in the range of n ≦ N and transferring it on the line. A traffic control method characterized in that the traffic control is performed within the following range.

Further, according to the present invention, in the above-described cell traffic control method, when reading out cells from the buffer onto the output line, control is performed such that cells belonging to the same frame are read out at predetermined intervals. Cell traffic control method is provided.

According to the present invention, in the above-described 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 traffic that can be transferred on the line is set. Thus, the traffic that can be transferred on the line for each band management unit w is the maximum number M of frames that can be transferred simultaneously belonging to the same management unit.
(W), the total number of frames n being transferred on the line
And means for counting the number of frames m (w) being transferred on the line for each band management unit. If the arriving cell is a valid cell and is the first cell or a single cell constituting an information frame, the cell At the time of arrival, n <N 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 A series of cells belonging to a frame are 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. If no cells are transferred on the output line, n ≦ N and m (w) ≦ M
A cell traffic control method is provided wherein the traffic on the output line is controlled within a specified value by reading from the buffer in the range of (w) and transferring the data on the line.

According to the present invention, in order to solve the above-mentioned problems, 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 In a frame transfer system in which a plurality of information frames are multiplexed and transferred on the same line at the same time, a cell detection unit that detects the arrival of a cell on the line, the type of the arriving cell, and the frame identifier displayed in the cell, The number m (w) of frames being transferred on the line for each of the total number n of frames being transferred on the output line and the bandwidth management unit w
A traffic observation unit that counts the number of frames, a frame buffer unit including a plurality of frame buffers that accumulate cells constituting the frame in units of frames when the number of frames exceeds a specified maximum number of frames, and the frame buffer unit. An empty frame buffer unit that manages an empty frame buffer of the first and second frames, 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 storage registration table that holds the value of the band management unit w in which the frame currently stored in the frame buffer exists, and the band management unit to which the arriving cell detected by the cell detection unit belongs is the frame. If the cell is being registered in the storage registration table, the cell is stored in the frame buffer unit. If it is not registered, the arriving cell is transferred to the output line if it is an intermediate cell constituting the information frame, or if it is the last cell, and if it is the first cell or a single cell, the cell is output by a predetermined judgment method. A cell traffic control circuit is provided, which determines whether to transfer to a line or store in a frame buffer.

According to the present invention, in the above-described cell traffic control circuit, the frame accumulation registration table in the frame transfer control unit may include a bandwidth management unit w in which the frame accumulated in the frame buffer unit exists. Along with the value, among the accumulated frames belonging to the bandwidth management unit, the first accumulated frame buffer number is the first accumulated frame buffer number, and the frame buffer number in which the most recently started frame is being accumulated is the latest accumulated frame buffer. It has a function of holding as a number, and when the arriving cell detected by the cell detection unit is a leading cell or a single cell constituting an information frame, the band management unit to which the cell belongs is registered in the frame accumulation registration table. When registration is not being performed and it is determined that the data is to be stored in the frame buffer. Hunt the empty frame buffer number from the empty frame buffer unit, write the cell on the frame buffer surface of the frame buffer unit having the frame buffer number, and change the frame buffer number to the first accumulated frame buffer number and the latest frame buffer number. With the value of the bandwidth management unit w,
If the cell is registered in the frame storage registration table, and the band management unit to which the cell belongs is being registered in the frame storage registration table, hunting for an empty frame buffer number from the empty frame buffer unit and The cell is written to the frame buffer surface of the frame buffer unit having the above, and the latest frame buffer number of the band management unit in the frame accumulation registration table is rewritten to the newly hunted frame buffer number from the empty frame buffer management unit. The cell traffic control circuit is characterized in that the frame buffer unit manages the frame buffer surface in which the frames belonging to the same band management unit are stored in the order of storage in the frame buffer.

Further, according to the present invention, in the above-described cell traffic control circuit, the frame transfer control section has a buffer number register during reading for registering a frame buffer number being read from the frame buffer section,
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 on the output line, the cell number from the frame buffer surface in the frame buffer unit of the number held in the buffer number register during reading is set to 1 When the cell is read and transferred on 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 band management unit w indicating that the frame is not being registered is registered in the frame accumulation registration table, The value of the head accumulation frame buffer number recorded in the table is read out, the value is registered in the read out buffer number register, and one cell is read out from the buffer surface in the frame buffer portion of the frame buffer number and transferred to the output line. Also, if the read cell is the last cell or a single cell constituting 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 buffer number register during reading is rewritten,
A cell that deletes the bandwidth management unit from the buffer number register during reading and the registration table during frame storage when another frame belonging to the same bandwidth management unit is not stored in the frame buffer unit. A traffic control circuit is provided.

[0018]

According to the present invention, 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 counted. The maximum number of frames N that can be transferred on the line, or the number of frames that can be transferred in a predetermined band when the number of frames during transfer of the VC is M
For a portion exceeding the limit, the frame transfer control unit accumulates the data in the frame buffer unit and smoothes the traffic to control the bandwidth for each VC.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS First, the outline of the present invention will be described. The present invention is directed to data communication in which an information frame is divided into cells and transferred. As shown in FIG. 7, a cell group constituting an information frame generally includes a first cell BOM, some intermediate cells COM, and a last cell EOM.
It is transferred at an interval T corresponding to 0. Even if the information frame length is short and the cell is formed, the frame can be constituted by one cell in some cases, and this cell is called a single cell SSM.

When a cell having a cell transfer speed V0 is converted into a cell and transferred on a line having a speed V (V> V0), the cell interval T is V / V0 cell time (one cell time corresponds to a line on the line having the speed). Is equivalent to the time required to transfer one cell).

A maximum of N frames (N = V / V0) can be simultaneously multiplex-transferred on a line of speed V. When n frames are being simultaneously transferred in a system that handles such communication, the used 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 the traffic at the cell level, the number of frames during transfer n (N ≧ n
.Gtoreq.0).

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

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

The cell traffic control circuit of the present embodiment is shown in FIG.
As shown in the figure, the cell detection unit 12, 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, a cell detector 12 identifies the function of detecting the arrival of a cell on the input line 11 and the type of the detected cell. The cell detection unit 12 converts the information frame into the ITU-T standard I.T. Taking a case where a cell is formed using the ATM adaptation layer type 3 defined by 362, 363 as an example, the cell type is identified by the ST field in the cell.

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

A value that can identify an individual frame, such as VPI / VCI / MID, 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 value of CI, and a plurality of frames having different MIDs can be multiplexed and transferred on the same VC.

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

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

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

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

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

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. new, accompanied by continuous accumulation display.

When a write instruction is received from the frame control unit 13, the frame buffer unit 14 sets the VPI / V in the parameter when the cell type is COM or EOM.
Based on the CI / MID value, the writing frame registration table 14a is searched, the frame buffer number corresponding to the VPI / VCI / MID value is read, and the frame buffer # 1, # 2,. Write cells.

When the cell type is COM, after writing the cell into the frame buffers # 1, # 2,..., #J, the VPI is written from the 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 is registered in the writing frame registration table 14a along with the frame buffer number Buf. No. The cell is written to the new frame buffer (in the case of SSM, VPI / VCI / MID is not registered in the writing frame registration table).

In this case, the frame buffer number Bu
f. No. new next frame buffer number register R
A value representing the “last 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
F, the frame buffer number Buf. No. VPI / VCI /
The MID is registered in the writing frame registration table 14a, and a cell is written in the frame buffer # 1, # 2,..., #J of the frame buffer number, and the cell frame buffer number Buf. No. The value indicating the “last frame” is written to the next frame buffer number registers R1, R2,..., Rj as the next frame buffer number of the new frame buffer number Buf. No
Frame buffer number registers R1, R corresponding to
,..., Rj are the frame buffer numbers Buf. N
o. new is written (in the case of SSM, VPI / VCI / MID is not registered in the writing frame registration table).

Then, the reading instruction from the frame control unit 13 to the frame buffer unit 14 is sent as a parameter to the frame buffer number Buf. No (r) is accompanied.
Accordingly, when receiving a read instruction from the frame transfer control unit 13, the frame buffer unit 14 sets the frame buffer number Buf. No (r) frame buffer #
, # 2,..., #J, one cell is read, and the type of the cell being read and the frame buffer number Buf. The values of the next frame buffer number registers R1, R2,..., Rj corresponding to the No (r) frame buffers # 1, # 2,.

When the type of the cell to be read out is EOM or SSM, the frame buffer unit 14 reads out 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 Is provided as the frame buffer number to be used next.

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

Regarding the measurement of the number of frames, refer to Japanese Patent Application No. Hei 6-38873, “Traffic measurement method and circuit thereof”.
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, cell type, frame identifier (VPI / VCI / MI)
Upon receiving D), the frame transfer control unit 13 starts the cell arrival processing shown in FIG.

If the cell type is not BOM or SSM but CO
If it is M or EOM, it searches the frame buffer accumulation registration table 13b to see if the VPI / VCI is being registered, and if it is being registered, transfers the cell to the frame buffer unit 14. Together with the parameter value for the frame buffer unit 14 to obtain VPI / V
A write instruction is issued together with the CI / MID value and the cell type (steps S1, S2, S3).

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

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

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

After the end of the write instruction to the frame buffer section 14, the frame buffer number of the VPI / VCI in the frame accumulation registration table 13b is newly set to the frame buffer number Buf. No. Rewrite to new (step S9).

On the other hand, when the VPI / VCI is not registered in the registration table 13b during frame buffer accumulation, the total traffic measurement value is (N-1) based on the measurement value of the traffic observation unit 16. (N is the maximum number of simultaneously transferable frames on the output line)
The traffic measurement value of PI / VCI is (M (VPI / VC
I) -1) VP when M (VPI / VCI)
Is determined to be less than or equal to the maximum number of simultaneously transferable frames in the specified band corresponding to the I / VCI value, and the result is Yes.
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 sends the frame buffer number B
uf. No. New, the cell is transferred to the frame buffer unit 14 and VPI / VCI / M is transmitted to the frame buffer unit 14 as a parameter value.
ID value, cell type, frame buffer number Buf. N
o. New, the writing instruction is performed together with the continuous accumulation display OFF, and the VPI / VCI value is registered in the frame accumulation registration table 13b.

At this time, the frame storage registration table 13
b, the first frame buffer number and the latest frame buffer number are 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 has arrived), or the arrival cell is output to the output line 17 in the arrival cell processing flow of FIG. Frame buffer unit 14 without transferring
Is transferred to the frame buffer 14 shown in FIG.
Starts the reading process from.

Here, in the frame transfer control section 13, the frame being read is managed by the buffer number register 13c during reading, and the cell of the next frame to be read is managed by the next reading register number.

First, the next read register number at the time when the reading process from the frame buffer unit 14 is started in the frame transfer control unit 13 is set to r (step S2).
1). Here, the reading of the buffer number register 13c empty / occupied display of the number r is read out, and if the display is "occupied", the following processing 3 is performed (step S22).

(Process 3) The frame buffer number Buf. No (r) is read out, and the parameter Buf. Along with No (r), a read instruction is issued (steps S23, S24).

When receiving the read instruction, the frame buffer unit 14 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 "last frame", If not, the value of the frame buffer number of the buffer number register 13c during reading 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 processing is terminated. Yes (Step S25-
S28).

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

When the frame transfer controller 13 starts reading from the frame buffer unit 14 and starts reading the buffer number register 13c corresponding to the next read register number r, the empty / busy display indicates "empty". First,
The whole traffic measurement value (the number of frames being transferred) in the traffic observation unit is checked, and if the measured value is (N-1) or less, processing 1 described below is performed. After updating the register number to r + 1, again in step S22, a new next read register number r '(= r
+1), the buffer number register 13c during reading
Is read and the process proceeds (step S3).
1, S32).

(Process 1) Here, first, the VPI / OFF of the display OFF during reading in the frame accumulation registration table 13b is set.
It is searched whether or not the VCI is registered, and if not, the next read register number is updated to r + 1, and the process ends (steps S33, S28).

In the case where there is a registration, furthermore, based on the measured value of the traffic observing section 16, the traffic measured value of the VPI / VCI is (M (VPI / VCI) -1) or less, and is displayed during registration and reading. OFF VPI / VCI is searched, and the frame buffer number of the corresponding VPI / VCI is read, and this value is stored in the reading buffer number register 1
3c is written as the frame buffer number, the empty / busy display (r) is set to "closed", and the reading-in-progress display of the VPI / VCI in the frame storage registration table 13b is rewritten to ON (steps S33 to S36).

Thereafter, the above-described process 3 after step S23 is performed. By using the above-described cell traffic control method of the present invention, transfer traffic can be controlled 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 hundreds to thousands of multiplexed communication channel bands without installing a separate FIFO buffer for each band management unit.

Further, in the cell traffic control system of the present invention, the input delay is transferred to the output line directly 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]

Therefore, as described in detail above, according to the present invention, a FIFO queue is not set for each bandwidth management unit,
It is possible to provide a cell traffic control circuit and a cell traffic control method capable of realizing traffic control capable of coping with a small amount of hardware even when the number of bandwidth management targets increases.

[Brief description of the drawings]

FIG. 1 is a diagram showing a circuit configuration of an embodiment for realizing a cell traffic control system according to 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 process) 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 divided into cells and transferred.

FIG. 8 is a diagram showing an example in which information frames divided into cells are multiplex-transferred on a line.

[Explanation of symbols]

11: input line, 12: cell detection unit, 13: frame transfer control unit, 14: frame buffer unit, 15: empty frame buffer management unit, 16: traffic observation unit, 13a
... Regulated bandwidth table, 13b ... Frame accumulation registration table, 13c ... Reading buffer number register, 14a
... Frame registration table during writing, # 1, # 2, ..., #
j: frame buffer, R1, R2,... Rj: next frame buffer number register.

Claims (6)

(57) [Claims] An information frame to be communicated is divided into a plurality of fixed-length cells, 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. A cell traffic control method for controlling cell traffic on the line, which is used for a frame transfer method to be transferred, wherein 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. Means for counting the number n of frames being transferred; and a buffer for storing cells constituting the frame when the number of frames exceeds the specified maximum number of frames, and the arrival cell is a valid cell. If the cell is the first cell or a single cell constituting an information frame, n
If <N, a series of cells belonging to the same frame as the relevant cell is transferred to the output line. If n = N, a series of cells belonging to the same frame as the relevant cell are transferred to the buffer while identifying the frame. For frames stored in the buffer, if the input cell is an invalid cell such as an empty cell, or if the input cell is stored in the buffer and the cell is not transferred on 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 out from the buffer in the range of N and transferring it on 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 predetermined intervals. 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 a maximum number of frames that can simultaneously transfer traffic that can be transferred on the line. 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 simultaneously transferable frames belonging to the same band management unit, and the total number of frames being transferred on the line n and means for counting the number of frames m (w) being transferred on the line for each band management unit. If the arriving cell is a valid cell and is the first cell or a single cell constituting an information frame, N at cell arrival
If <N and m (w) <M (w), a series of cells belonging to the same frame as the cell is transferred to 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 stored in the buffer while identifying the frame, and for the frame stored in the buffer, whether the input cell is an invalid cell such as an empty cell, or By storing input cells in a buffer and not transferring cells on the output line, reading from the buffer in the range of n ≦ N and m (w) ≦ M (w) and transferring them on the line, A cell traffic control method, wherein cell traffic on the output line is controlled within a specified value. 4. An information frame to be communicated is divided into a plurality of fixed-length cells, or transferred as a single cell on a line of a predetermined speed, and a plurality of information frames are simultaneously multiplex-transmitted on the same line. A cell detector for detecting the arrival of a cell on the line, the type of the arriving cell and the frame identifier displayed in the cell, a total number of frames n and a band being transferred on the output line. A traffic observation unit that counts the number m (w) of frames being transferred on the line for each management unit w, and stores cells constituting the frame in units of frames when the number of frames exceeds a specified maximum number of frames A frame buffer unit comprising a plurality of frame buffers, and a vacant frame buffer unit for managing a vacant frame buffer of the frame buffer unit. A frame transfer control unit for determining whether to store the arriving cell in the frame buffer unit or to transfer the arriving cell to the output line, wherein the frame transfer control unit determines whether the frame being stored in the frame buffer unit is If there is a frame storage registration table holding the value of the existing band management unit w, and the band management unit to which the arriving cell detected by the cell detection unit belongs is being registered in the frame storage registration table, Storing the cell in the frame buffer unit,
If the arriving cell is not an intermediate cell constituting an information frame when not being registered, or if it is the last cell, the cell is transferred to the output line. A cell traffic control circuit for deciding whether to transfer or accumulate in a frame buffer. 5. The cell traffic control circuit according to claim 4, wherein the frame accumulation registration table in the frame transfer control unit has a value of a band management unit w in which a frame accumulated in the frame buffer unit exists. In addition, among the accumulated frames belonging to the band management unit, the first accumulated frame buffer number is the first accumulated frame buffer number, and the frame buffer number in which the most recently started frame is accumulated is the latest accumulated frame buffer number. In the case where the arriving cell detected by the cell detection unit is a head cell or a single cell constituting 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 data is not stored in the frame buffer Hunt an empty frame buffer number from the system buffer unit, write the cell on the frame buffer surface of the frame buffer unit having the frame buffer number, and use the frame buffer number as the first accumulated frame buffer number and the latest frame buffer number. Registered in the frame accumulation registration table together with the value of the management unit w, and when the band management unit to which the cell belongs is being registered in the frame accumulation registration table, an empty frame buffer number from an empty frame buffer unit And write the cell to 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 the 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 said frame transfer control unit has a buffer number register for reading registering a frame buffer number being read from said frame buffer unit. A display flag indicating whether or not a frame belonging to the band management unit being registered in the frame accumulation registration table in the transfer control unit is being read is held, and the arrival cell detected by the cell detection unit is an invalid cell. When one or more arriving cells are stored in the frame buffer and the cell is not transferred on the output line, one cell is read from the frame buffer surface in the frame buffer of the number held in the buffer number register during reading. Transfer to the output line, or read the frame into the read buffer number register. When the buffer number is not registered, the band management unit w indicating that n ≦ N−1 and m (w) ≦ M−1 and the value of the read display flag is not being read is registered during the frame accumulation. If it is registered in the table, the value of the head accumulation frame buffer number recorded in the table is read out, the value is registered in the read buffer number register, and one cell from the buffer surface in the frame buffer unit of the frame buffer number is read out. When the read out cell is the last cell constituting the information frame or the single cell, the next frame buffer number belonging to the same band management unit is read out from the frame buffer unit, and the read out cell is read out and transferred to the output line. Rewrite the value of the buffer number register so that the same 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.