JPH10294742A - Input buffer queue control method of atm exchange - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the use efficiency of resources and the operation efficiency of a system by accumulating user cells and control cells in a shared buffer queue and setting an abandonment threshold, that corresponds to a speed at which a cell is read from the buffer queue when a processing part becomes a high load state. SOLUTION: A buffer queue 1 is provided with a queue, which is shared by a user cell and a control cell in an input cell and a user cell and a control cell are successively accumulated in the queue 1 in common. A read speed detecting part 3 detects the load state of a processing part 2 at all times and calculates a new abandonment threshold that corresponds to a read speed, and a queue-controlling part 4 sets the abandonment threshold to a queue in the queue 1. It calculates an abandonment threshold that increases a cell accumulable amount of a queue and sets it, when the part 2 is in a low load state and calculates an abandonment threshold that reduces a cell accumulable amount of a queue and sets it when the part 2 is in a high load state.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an input buffer queue control method for an ATM switch, and more particularly to an input buffer queue control for an ATM switch which determines whether to discard input cells based on a discard threshold set in the input buffer queue. It is about the method.

[0002]

2. Description of the Related Art Conventionally, in an ATM switch, when discarding input cells is determined based on a discard threshold set in an input buffer queue, a queue for user cells for processing user cells in the input buffer queue is provided. A control cell queue for processing the control cell is separately provided, and the discard of the input cell is determined. FIG.
Is an explanatory diagram showing a conventional input buffer queue control method, wherein 5 is a buffer queue for temporarily storing input cells, 6 is for performing various processing of the ATM switch,
This is a processing unit that sequentially reads cells from the buffer queue 5 and processes them.

In this case, as shown in FIG. 5, in a buffer queue 5, a user cell queue 51 for processing a user cell 41 and a control cell queue 52 for processing a control cell 42 are individually provided. The cells input to the buffer queue 5 are stored in the user cell queue 51 or the control cell queue 52 according to the type of the cell. In the user cell queue 51 and the control cell queue 52, discard thresholds TH1 and TH2 for making a discard judgment of a cell are fixedly provided by software or the like.

[0006] Unless the cell storage amounts of the queues 51 and 52 exceed the discard thresholds TH1 and TH2, input cells are input to the corresponding queues 51 and 52, respectively. Further, by setting the discard threshold TH2 of the control cell queue 52 to be larger than the discard threshold TH1 of the user cell queue 51, when the load on the processing unit 6 becomes large, the control cell queue Is delayed later than the user cell, and communication control performed using the control cell is guaranteed.

[0005]

However, in such a conventional input buffer queue control method, individual queues 51 and 52 corresponding to the type of input cell are provided in the input buffer queue, and each queue 51 ,
Since the discard threshold is fixedly set for 52, when the number of input cells is small, resources are wasted as much as the set number of queues, resulting in poor buffer capacity utilization efficiency. There was a problem.

Further, since the discard thresholds TH1 and TH2 are fixed, when the load on the processing unit 6 increases, the speed at which the processing unit 6 reads cells from the buffer queue 5, ie, the cell reading speed, increases. Since the delay is slow, cells are gradually accumulated in the buffer queue 5, and there is a problem that the high load state of the processing unit is prolonged. An object of the present invention is to solve such a problem, and an object of the present invention is to provide an input buffer queue control method for an ATM exchange that can efficiently use system resources and operate the system efficiently.

[0007]

In order to achieve the above object, an input buffer queue control method for an ATM exchange according to the present invention is to sequentially store user cells and control cells among input cells in a buffer queue sequentially. However, when the load state of the processing unit becomes high, the cell reading speed when reading cells from the buffer queue is detected, and a discard threshold value corresponding to the cell reading speed is set in the buffer queue. Things. Therefore, user cells and control cells are sequentially accumulated in the buffer queue in common, and when the load on the processing unit increases, a discard threshold corresponding to the detected cell read speed is set in the buffer queue. Is done.

Further, when the load state of the processing unit becomes high or when the cell reading speed is relatively high, the discard threshold is set so that the amount of cells that can be stored in the buffer queue becomes large, and the cell reading speed is set. Is relatively small, the discard threshold is set so that the cell storage capacity of the buffer queue becomes small. Therefore, when the load state of the processing unit becomes high, and when the cell reading speed is relatively high, the discard threshold is set so that the amount of cells that can be stored in the buffer queue becomes large, and the cell reading speed becomes relatively high. If it is smaller, the discard threshold is set so that the amount of cells that can be stored in the buffer queue becomes smaller. Further, when the cell accumulation amount of the buffer queue becomes equal to or more than the discard threshold, the user cells are discarded among the newly arrived input cells, and the control cells are accumulated in the buffer queue. . Therefore, when the cell accumulation amount of the buffer queue becomes equal to or larger than the discard threshold, the user cell among the newly arrived input cells is discarded, and the control cell is accumulated in the buffer queue.

[0009]

Next, the present invention will be described with reference to the drawings. FIG. 1 shows an AT according to an embodiment of the present invention.
FIG. 4 is an explanatory diagram showing an input buffer queue control method of the M exchange. In FIG. 1, reference numeral 1 denotes a buffer queue for temporarily storing input cells, and 2 denotes a processing unit which performs various processes such as sequentially reading cells from the buffer queue 1. A queue for storing control cells in common is provided.

[0010] When the load state of the processing unit 2 becomes high, the processing unit 2 starts detecting the speed at which the processing unit 2 reads cells from the input buffer queue, that is, the cell reading speed, and discards the cells according to the cell reading speed. This is a cell reading speed detection unit that calculates a threshold value. 4 is a reading speed detecting unit 3
This is a queue control unit that sets the discard threshold calculated in the above in the queue in the buffer queue 1.

Next, the operation of the present invention will be described with reference to FIG. 2A and 2B are explanatory diagrams showing queue states according to the present invention. FIG. 2A shows a case where the processing unit is in a low load state, and FIG. 2B shows a case where the processing unit is in a high load state. In the figure, reference numeral 11 denotes a queue provided in the buffer queue 1 for storing user cells and control cells in common, 21 denotes a user cell, 22 denotes a control cell, TH_H and TH_L denote a discard threshold, and W denotes a discard threshold. This is a range in which the threshold can be taken, that is, a threshold range.

When the cell storage amount in the queue 11 exceeds the discard thresholds TH_H and TH_L, the input cells are discarded, and the input cells are input to the queue 11 as long as they do not exceed the discard thresholds TH_H and TH_L. As shown in FIG. 2A, when the processing unit 2 is in a low load state, the discard threshold is T
A relatively high value is set as H_H, and the cell storage capacity of the queue 11 increases.

On the other hand, when the processing unit 2 is in a high load state, the cell reading speed when the processing unit 2 reads cells from the queue 11 decreases. For this reason, the amount of cells stored in the queue 11 increases, and the load on the entire system further increases. Therefore, the reading speed detecting unit 3 always detects the load state of the processing unit 2, and when the load state becomes higher than a predetermined reference value, detects the cell reading speed based on the processing operation of the processing unit 2, and detects the cell reading speed. A new discard threshold value is calculated according to the read speed.

In this case, as the reading speed decreases,
An appropriate value that is less than the originally set drop threshold,
For example, TH_L is calculated and notified to the queue control unit 4. In response to this, the queue control unit 4 sets TH_L as a new discard threshold for the queue 11 in the buffer queue 1 as shown in FIG. Therefore, in this case, since a relatively low discard threshold TH_L is set, the amount of cells that can be stored in the queue 11 is reduced,
Subsequent cells are discarded, and an increase in processing load on the processing unit 2 is suppressed.

Thereafter, when the reading speed detecting section 3 confirms that the reading speed of the processing section 2 has increased, it is determined that the load state of the processing section 2 has decreased, and a new reading state corresponding to the reading speed is determined. Calculate the discard threshold. In this case, an appropriate value higher than the discard threshold TH_L in the high load state, for example, TH_
H is calculated and notified to the queue control unit 4.

In response to this, the queue control unit 4 operates as shown in FIG.
As shown in (b), TH_ is used as a new discard threshold.
L is set for the queue 11 in the buffer queue 1.
Therefore, in this case, the relatively high discard threshold TH
Since _H is set, the amount of cells that can be stored in the queue 11 increases, and subsequent cells are not discarded.

As described above, the buffer queue 1 is provided with the common queue 11 for the user cell and the control cell, and the readout speed detector 3 calculates a discard threshold corresponding to the readout speed detected by the processor 2. Since the discard threshold is set to the queue 11 in the buffer queue 1 by the queue control unit 4, when the processing unit 2 is in a low load state, the discard threshold for increasing the cell storage capacity of the queue 11 is set. By calculating and setting the value TH_H and calculating and setting the discard threshold TH_L for reducing the cell storage capacity of the queue 11 when the processing unit 2 is in a high load state, the resources of the system can be used efficiently, The system can be operated efficiently.

As shown in FIG. 3, the cell discard determination may be changed according to the type of the cell. FIGS. 3A and 3B are explanatory diagrams showing cell discard determination. FIG. 3A shows the case of a user cell, and FIG. 3B shows the case of a control cell. now,
It is assumed that various cells are accumulated in the queue 11 up to the discard threshold TH.

In this state, a new user cell 2
When 1 arrives, the arriving user cell 21 is discarded as shown in FIG. On the other hand, when a new control cell 22 arrives, as shown in FIG.
The arriving control cell 22 is stored in the queue 11. In this case, the control cells 22 are sequentially stored until the storage capacity of the queue 11 is exhausted. Thereby, the probability that control cells required for communication control are discarded can be reduced, and stable communication control can be maintained.

[0020]

As described above, according to the present invention, the user cells and the control cells among the input cells are sequentially accumulated in the buffer queue in common, and when the load state of the processing unit becomes high, the buffer queue becomes high. To detect the cell read speed when reading cells from, to set a discard threshold in the buffer queue according to the cell read speed,
Further, when the load state of the processing unit becomes high, and when the cell reading speed is relatively high, the discard threshold is set so that the amount of cells that can be stored in the buffer queue becomes large,
When the cell reading speed is relatively low, the discard threshold is set so that the cell storage capacity of the buffer queue becomes small.

Therefore, as compared with the case where the input cell is discarded based on a fixed discarding threshold value as in the related art, the system resources can be used more efficiently and the system can be operated more efficiently. In addition, when the cell accumulation amount in the buffer queue becomes equal to or larger than the discard threshold, the user cells are discarded among the newly arrived input cells, and the control cells are accumulated in the buffer queue. The probability that control cells required for control are discarded can be reduced, and stable communication control can be maintained.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing an input buffer queue control method for an ATM exchange according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing a state of a queue.

FIG. 3 is an explanatory diagram showing cell discard determination.

FIG. 4 is an explanatory diagram showing a conventional input buffer queue control method.

FIG. 5 is an explanatory diagram showing a conventional cell discard determination.

[Explanation of symbols]

1 ... buffer queue, 11 ... queue, 2 ... processing unit, 3 ...
Read speed detection unit, 4 ... queue control unit, 21 ... user cell, 22 ... control cell.

Claims (3)

[Claims] 1. A buffer queue in which input cells are sequentially accumulated and cells accumulated by a processing unit for performing various processes are sequentially read and processed, and a cell accumulation amount of the buffer queue is determined by a buffer queue. In the input buffer queue control method of the ATM exchange for discarding newly arriving input cells when the threshold value is equal to or greater than the discard threshold value set in, the user cell and the control cell among the input cells are shared by the buffer queue. When the load state of the processing unit becomes high, the cell read speed for reading cells from the buffer queue is detected, and a discard threshold corresponding to the cell read speed is set in the buffer queue. An input buffer queue control method for an ATM exchange characterized by the above-mentioned. 2. The input buffer queue control method for an ATM exchange according to claim 1, wherein the cell storage capacity of the buffer queue is increased when the load state of the processing unit increases, and when the cell read speed is relatively high. The ATM switching system is characterized in that the discard threshold is set so as to increase, and when the cell reading speed is relatively low, the discard threshold is set so that the amount of cells that can be stored in the buffer queue is reduced. Input buffer queue control method. 3. The input buffer queue control method for an ATM exchange according to claim 1, wherein, when the cell accumulation amount of the buffer queue becomes equal to or larger than a discard threshold, among the input cells newly arriving, An input buffer queue control method for an ATM exchange, comprising discarding user cells and storing control cells in a buffer queue.