JP2000124905A - Device and method for atm transmission - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide ATM transmission equipment capable of performing efficient priority control as a whole suppressing the priority transmission of certain information more than needed. SOLUTION: This equipment is provided with a cell holding means 11 for storing cells from an upstream cell transmitting means 2, transmission cell selecting means 12 for determining the priority to transmit the cells stored in this cell holding means to a downstream cell transmitting means 3 and minimum cell transmission interval designating means 13 for applying the minimum cell transmission interval information to this transmission cell selecting means and the transmission cell selecting means is provided for determining the priority of respective cells based on the priority class information contained in respective cells and the minimum cell transmission interval information.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ATM (asynchronous transmission mode) transmission for determining an efficient transmission order as a whole by designating a minimum necessary cell transmission interval based on, for example, characteristics of information to be transmitted. The present invention relates to an apparatus and a transmission method.

[0002]

2. Description of the Related Art FIG. 9 is a block diagram showing a configuration example of a conventional ATM transmission apparatus. In the figure, the ATM transmission device 51 has a cell holding unit 51a for temporarily storing cells from the upstream cell transmission unit 52 and an order for transmitting the cells stored in the cell holding unit 51a to the downstream cell transmission unit 53. And a transmission cell selecting means 51b for determining.

[0003] Cells from a plurality of cell transmission means 52 on the upstream side are temporarily stored in a cell holding means 51a until processed by a transmission cell selection means 51b. Transmission cell selection means 5
1b, when it is time to send a cell to the downstream cell transmission means 53, among the cells stored in the cell holding means 51a, refers to the priority class information included in the header part of the cell, and determines the higher priority. The cells are selected in order from the cell and transmitted to the downstream cell transmission means 53.

FIG. 10 is an operation explanatory diagram showing this state. The cells have higher priority in the order of class 1 and class 2, and the transmission time per cell is the same, 34 μs, both when the cell arrives and after multiplexing. FIG. 7A shows a state in which a cell arrives at the ATM transmission device 51. The cell C1a of class 1 arrives in the order of the cell C1b, and the cell C2a of class 2 arrives at the same time as the cell C1b. ATM transmission device 51
After the multiplexing in the cell C1, as shown in FIG.
a, the cell C1b, and the cell C2a in order of higher priority.

[0005]

By the way, the cell to be transmitted may have a certain amount of variation due to the final processing method of the information to be transmitted, even if the fluctuation of the transmission time of each cell in the transmission path is taken into consideration. There may be a case in which a characteristic that does not require a cell transmission interval of less than an hour is included.

For example, in the case where a speech signal that is PCM-coded at 64 kb / s is transmitted as cells, if each cell contains 384 bits of information, cells are transmitted at an average interval of 6 ms including fluctuations. It would be a good calculation if it had been done.

However, in the asynchronous transmission mode, the transmission delay of each cell differs depending on the transmission path and transmission timing. Therefore, even if cells are generated at equal intervals, if the moment on the transmission path in the middle is taken, the cell interval becomes shorter. May be. Even in this case, since the conventional transmission device only determines the priority based on the priority class information, cells are transmitted at an interval shorter than necessary, and as a result, the transmission timing of cells having a relatively low priority class is delayed. is there.

The present invention has been made to solve such a conventional problem, and an ATM transmission apparatus capable of suppressing unnecessary transmission of certain information more than necessary and performing efficient priority control as a whole. And a transmission method.

[0009]

An ATM transmission apparatus according to the present invention has a cell holding means for storing cells from an upstream cell transmission means, and transmits the cells stored in the cell holding means to a downstream cell transmission means. Transmission cell selection means for determining a transmission order; and minimum cell transmission interval designating means for giving the minimum cell transmission interval information to the transmission cell selection means. The transmission cell selection means includes priority class information and minimum cell information contained in each cell. The priority order of each cell is determined based on the transmission interval information.

According to the present invention, it is possible to obtain an ATM transmission apparatus capable of suppressing unnecessary transmission of certain information more than necessary and performing efficient priority control as a whole.

[0011]

DETAILED DESCRIPTION OF THE INVENTION An ATM according to claim 1 of the present invention.
The transmission device includes a cell holding unit that stores cells from the upstream cell transmission unit, a transmission cell selection unit that determines a priority order for transmitting the cells stored in the cell holding unit to the downstream cell transmission unit, and a transmission cell selection unit. Means for designating minimum cell transmission interval information for giving minimum cell transmission interval information to the means, wherein the transmission cell selecting means determines the priority order of each cell based on the priority class information and the minimum cell transmission interval information contained in each cell. It is.

[0012] According to the present invention, the transmission cell selection means can determine each cell from the minimum cell transmission interval information for each transmission information type specified by the minimum cell transmission interval specification means, in addition to the priority class information included in the header of the cell. Determine the priority order. In the determination of the priority order, if there is a cell with a high priority class and a cell with a low priority class, if the time of the minimum transmission interval has elapsed from the cell previously processed for the cell with a high priority class, the priority order according to the priority class information It will be attached. However, if the time has elapsed less than the minimum transmission interval, it is determined that the cell with the lower priority class has priority. By this processing, cell transmission at an interval shorter than necessary is suppressed,
This has the effect that the delay of the cell of the lower priority class can be reduced.

According to a second aspect of the present invention, there is provided an ATM transmission apparatus, comprising: a cell holding means for storing cells to be transmitted to downstream cell transmission means; and a transmission cell for determining an order for storing cells from the upstream cell transmission means in the cell holding means. Selecting means, and minimum cell transmission interval designating means for giving the minimum cell transmission interval information to the transmission cell selecting means, wherein the transmission cell selecting means retains each cell from the priority class information and the minimum cell transmission interval information contained in the cell. The order of storing in the means is determined.

[0014] According to the present invention, the transmission cell selection means can determine each cell from the minimum cell transmission interval information for each transmission information type designated by the minimum cell transmission interval specification means, in addition to the priority class information contained in the header of the cell. Determine the priority order. The determination of the priority order is the same as that of the first aspect. This processing has an effect that transmission of cells at intervals shorter than necessary is suppressed, and the delay of a cell having a relatively lower priority class can be reduced.

According to a third aspect of the present invention, in the ATM transmission apparatus according to the second aspect of the present invention, when the cells arrive from the upstream cell transmission means, the cells stored in the cell holding means are exchanged and controlled. It is provided with exchange means.

According to the present invention, the cell order switching means has an effect of rearranging cells arranged in the order of transmission on the cell holding means, including cells newly arriving from the cell transmission means.

According to a fourth aspect of the present invention, in the ATM transmission method, cells from an upstream cell transmission unit are stored in a cell holding unit, and priority of each cell is determined based on priority class information and minimum cell transmission interval information included in each cell. The order is determined, and each cell is transmitted to the downstream cell transmission means in accordance with the determined priority order.

According to the present invention, the priority of each cell is determined not only from the priority class information contained in the header of the cell but also from the minimum cell transmission interval information for each type of transmission information. In the determination of the priority order, if there is a cell having a high priority class and a cell having a low priority class, if the time of the minimum transmission interval has elapsed from the cell previously processed for the cell having the high priority class, the priority order according to the priority class information is given. It will be attached. However, if the time has elapsed less than the minimum transmission interval, it is determined that the cell in the lower priority class has priority. This processing has an effect that transmission of cells at intervals shorter than necessary is suppressed, and the delay of a cell having a relatively lower priority class can be reduced.

In the ATM transmission method according to the present invention, the priority order of each cell is determined based on the priority class information and the minimum cell transmission interval information included in the cell from the upstream cell transmission means, and the determined priority order is determined. , Each cell is stored in the cell holding means, and the stored cells are transmitted to the downstream cell transmission means in the order of priority.

According to the present invention, the priority of each cell is determined not only from the priority class information contained in the header of the cell but also from the minimum cell transmission interval information for each type of transmission information. The determination of the priority order is the same as that of the fourth aspect. This processing has an effect that transmission of cells at intervals shorter than necessary is suppressed, and the delay of a cell having a relatively lower priority class can be reduced.

Hereinafter, an embodiment of the present invention will be described with reference to FIG.
This will be described with reference to FIG.

(Embodiment 1) FIG.
FIG. 2 is a block diagram illustrating Embodiment 1 of a TM (asynchronous transmission mode) transmission device. In the figure, an ATM transmission device 1
Is a cell holding means 11 for temporarily storing cells from the upstream cell transmission means 2 and a transmission cell selection for determining a transmission order for transmitting the cells stored in the cell holding means 11 to the downstream cell transmission means 3. Means 12 and minimum cell transmission interval specifying means 13 for specifying the minimum cell transmission interval.

FIG. 2 is a block diagram that embodies the configuration of FIG. 1. The cell holding means 11 includes a plurality of FIFOs for each priority class.
O memory 11a to 11n, transmission cell selecting means 1
Reference numeral 2 denotes a CPU 12a and a cell interval holding memory 12b for recording a cell sending interval, and a minimum cell sending interval designating means 13 comprises a minimum cell sending interval holding memory 13a.

Next, referring to the flowchart shown in FIG. 3 and the operation explanatory diagram shown in FIG. 4, the CPU 12a
A process of selecting cells stored in the FIFO memories 11a to 11n and transmitting the cells to the downstream cell transmission means 3 will be described.

First, the FIFO memory 11a having the highest priority class is temporarily designated as a memory from which cells are read out of the cell holding means 11 (step S1). Next, the FIFO memory 11a is searched in the cell holding means 11 for each priority class in which one or more cells are stored in descending order of the priority class (step S2). In the example of FIG. 4, the FIFO memory 11a storing the cell C1a of class 1 is selected.

Next, for the priority class corresponding to step S2, the minimum cell transmission interval A recorded in the minimum cell transmission interval holding memory 13a, and the cell transmission interval recording B recorded in the cell interval holding memory 12b. Are compared (step S3).

As a result, the minimum cell transmission interval holding memory 1
3a, the cell interval holding memory 12 is set based on the minimum cell transmission interval A.
If the record B of the cell transmission interval of b is smaller (step S4), the process returns to step S2. The FIF with the next highest priority and one or more cells stored therein
Search the O memory 11b. In the example of FIG. 4, since the cell interval of class 1 is 68 μs and the setting of the minimum cell transmission interval is 6 ms, the process returns to step S2, and the FIFO memory 11b storing the cells of class 2 is searched. .

If the record B of the cell transmission interval of the cell interval holding memory 12b is larger than the minimum cell transmission interval A of the minimum cell transmission interval designating means 13, the cells of the target priority class are transferred to the downstream cell transmission means 3. Send (Step S
5) Update the record of the cell transmission interval in the cell interval holding memory 12b (step S6).

By the above processing, as shown in FIG. 4B, the transmission order is the order of the cell C1a, the cell C2a, and the cell C1b. As a result, the cell C2a of class 2 is
Can be sent 34 μs earlier and the delay is smaller. Although the cell C1b of class 1 is delayed by that amount, the minimum cell transmission interval is 6
There is no inconvenience because the setting is not more than ms. In this way, it is possible to reduce the delay of a cell having a low priority class while ensuring the minimum priority for a cell having a high priority class.

(Embodiment 2) FIG.
FIG. 6 is a block diagram showing a second embodiment of a TM transmission apparatus, in which the same components as those in the first embodiment are denoted by the same reference numerals and described.

In this embodiment, the upstream cell transmission means 2
The transmission cell selecting means 12 having received the cell from the reference cell refers to the priority class information on the cell and the minimum cell transmission interval information for each transmission information type designated by the minimum cell transmission interval designation means 13 and transmits the cell from the cell holding means 11. The cell order is determined and arranged on the cell holding means 11. The procedure for determining the priority order is the same as in the first embodiment.

FIG. 6 is a block diagram that embodies the configuration of FIG. 5. As in the first embodiment, the cell holding means 11 is composed of a plurality of FIFO memories 11a to 11n for each priority class. 12 is a CPU of a computer configuration
The minimum cell transmission interval designating means 13 comprises a minimum cell transmission interval holding memory 13a.

(Embodiment 3) FIG.
FIG. 10 is a block diagram showing a third embodiment of a TM transmission apparatus, in which the same components as those in the above-described second embodiment will be denoted by the same reference numerals.

In this embodiment, a cell order exchange means 14 is provided, and the cell order is dynamically changed by controlling the cell holding means 11 when a cell arrives from the upstream cell transmission means 2. . That is, the cells arranged in the transmission order on the cell holding unit 11 are rearranged including the cells newly arrived from the cell transmission unit 2.

FIG. 8 is a flow chart for explaining the operation in the present embodiment. In the procedure shown in FIG. 3, the processing in steps S1 to S6 is the same, and the processing in step S7 is newly added. Is shown.
The process of step S7 is a cell order exchange process for dynamically exchanging cells arranged in the order of transmission on the cell holding unit 11 when a cell arrives from the upstream cell transmission unit 2.

In the case of the second embodiment which does not include the processing of step S7, in order to perform the processing of step S3 on the cells arriving before and after on the time axis, the cell holding means 11
In this embodiment, cells can be sent to the downstream cell transmission means 3 with a shorter residence time, although it is necessary to make the cell residence time in the cell longer than a certain level.

[0037]

According to the present invention, the required minimum cell transmission interval is specified in consideration of the characteristics of the information to be transmitted, and this information is added to the priority by the fixed priority class specification to determine the cell transmission order. By deciding, it is possible to reduce the delay of the cell of the low priority class while securing the minimum priority for the cell of the high priority class, and it is possible to perform an efficient priority control as a whole. The effect is obtained.

[Brief description of the drawings]

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

FIG. 2 is a block diagram that embodies the configuration of FIG. 1;

FIG. 3 is a flowchart showing the operation of the first embodiment.

FIG. 4 is an operation explanatory diagram of the first embodiment.

FIG. 5 is a block diagram showing Embodiment 2 of the present invention.

FIG. 6 is a block diagram that embodies the configuration of FIG. 5;

FIG. 7 is a block diagram showing a third embodiment of the present invention.

FIG. 8 is a flowchart showing the operation of the third embodiment.

FIG. 9 is a block diagram showing an example of a conventional ATM transmission device.

FIG. 10 is a diagram illustrating the operation of a conventional ATM transmission device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ATM transmission apparatus 2 (upstream) cell transmission means 3 (downstream) cell transmission means 11 cell holding means 11a-11n FIFO memory 12 transmission cell selection means 12a CPU 12b cell interval holding memory 13 minimum cell transmission interval designation means 13a minimum Cell sending interval holding memory 14 Cell order exchange means

Claims (5)

[Claims] 1. A cell holding means for storing cells from an upstream cell transmitting means, a transmission cell selecting means for determining a priority order for transmitting cells stored in said cell holding means to a downstream cell transmitting means, Minimum cell transmission interval designating means for giving the minimum cell transmission interval information to the transmission cell selecting means, wherein the transmission cell selecting means has a priority class of each cell based on the priority class information included in each cell and the minimum cell transmission interval information. An ATM transmission device for determining an order. 2. A cell holding means for storing cells to be transmitted to a downstream cell transmission means; a transmission cell selection means for determining an order of storing cells from an upstream cell transmission means in said cell holding means; A minimum cell transmission interval designating unit that gives minimum cell transmission interval information to the cell selection unit, wherein the transmission cell selection unit holds the cells based on the priority class information and the minimum cell transmission interval information included in the cells. An ATM transmission device, which determines the order of storing in the means. 3. The invention according to claim 2, further comprising a cell order exchange means for controlling the exchange of cells stored in the cell holding means when a cell arrives from an upstream cell transmission means. ATM transmission equipment. 4. A cell from an upstream cell transmission unit is stored in a cell holding unit, and a priority order of each cell is determined based on priority class information and minimum cell transmission interval information included in each cell. An ATM transmission method, wherein each cell is transmitted to a downstream cell transmission means in order. 5. A priority order of each cell is determined based on priority class information and minimum cell transmission interval information included in a cell from an upstream cell transmission means, and each cell is stored in a cell holding means in accordance with the determined priority order. An ATM transmission method, wherein the cells are stored, and the stored cells are transmitted to a downstream cell transmission means in the priority order.