KR100951882B1 - Method and apparatus for ATM-based delay adaptive scheduling according to traffic types - Google Patents

Abstract

Disclosed is a delay adaptive scheduling method and apparatus according to an asynchronous transmission mode based traffic type. In the delay-adaptive scheduling method according to the traffic type based on the asynchronous transmission mode, generating a service information including a traffic type, a service priority, and a service end time by classifying cells according to traffic types. Setting a system waiting time for serving a cell, determining whether to service the cell based on the service information and the system waiting time, and outputting the cell in which the service is determined. This reduces the average delay per cell in the switch using different delay parameters for each traffic type, thereby processing a large amount of data in the same amount of time, ultimately improving overall switch performance.

Asynchronous Transfer Mode, ATM, Traffic

Description

Method and apparatus for ATM-based delay adaptive scheduling according to traffic types

1 is a block diagram illustrating an internal configuration of an embodiment of a delay adaptive scheduling apparatus according to a traffic type based on a conventional asynchronous transmission mode.

2 is a flowchart illustrating a process of generating service information in a delay adaptive scheduling apparatus according to a traffic type based on a conventional asynchronous transmission mode;

3 is a flowchart illustrating a process of determining a cell to be serviced according to service information in a delay adaptive scheduling apparatus based on a traffic type based on a conventional asynchronous transmission mode;

4 is a flowchart provided to explain an operation method of a delay adaptive scheduling method according to an asynchronous transmission mode based traffic type according to the present invention.

Explanation of symbols on the main parts of the drawings

110: scheduling unit 130: storage unit

150: output unit 170: input and output management unit

190 control unit 200 ATM switch

The present invention relates to a delay adaptive scheduling method according to the traffic type based on the asynchronous transmission mode, and more particularly, the asynchronous transmission mode-based traffic capable of adaptive scheduling according to the propagation delay time by setting different delay parameters for each traffic type. It relates to a delay adaptive scheduling method and apparatus according to the type.

Due to the development of high speed switching technology and optical transmission technology, high speed data transmission and broadband service from hundreds of Mbps to several tens of Gbps are possible in the communication network, and B-ISDN (Asynchronous Transfer Mode: ATM) based Broadband Integrated Services Digital Network currently offers broadband multimedia services such as video on demand (VOD) and video conferences.

One of the important considerations in designing a communication network to support such a broadband multimedia service is to ensure sufficient bandwidth to provide a smooth service. In other words, the network service provider and the user in the network connection should be able to achieve the optimization of the bandwidth usage. At this time, an agreement will be made to guarantee the appropriate QoS for each type of traffic, and the average delay is an important factor in determining the quality of service (QoS) requirements. Therefore, delay bound in the intermediate exchange node becomes an important feature.

ATM networks have been proposed with scheduling algorithms for relocating bandwidth according to the requirements of each source, and algorithms suitable for high speed, efficient and performance boundaries. Most scheduling algorithms, however, do not distinguish between time-sensitive and loss-sensitive traffic during scheduling, and do not guarantee end-to-end delay boundaries required by time-sensitive traffic. This results in wasted bandwidth to ensure end-to-end delay boundaries required by time-sensitive traffic.

On the other hand, algorithms such as fair queuing (FQ) operating in a round-robin fashion cannot provide different available bandwidths to different sources, and methods designed to solve this problem are weighted equal queuing. Weighted fair queueing (WFQ) or generalized processing sharing (GPS) methods have been proposed.

However, output conflict and head of line blocking in an input queuing packet switching system using such a queuing model cause a problem of reducing throughput by increasing end-to-end delay. In addition, the proposed LA (Look Ahead) and PIM (Parallel Interactive Matching) algorithms have a problem of increasing computational complexity in scheduling.

In order to solve the various problems described above, the applicant has applied for a patent for the 'appropriate adaptive scheduling apparatus according to the traffic type based on the asynchronous transmission mode' of the domestic application number 2001-36013. The traffic is based on asynchronous transmission mode by segmenting and processing the input traffic to improve QoS guarantee and efficiency for each traffic type, and to ensure fair transmission of queues, thereby providing different available bandwidths to different sources. Disclosed is a delay adaptive scheduling apparatus and method.

Hereinafter, the present invention will be described in detail with respect to the delay adaptive scheduling apparatus and method according to the type of traffic based on the asynchronous transmission mode of the present applicant.

 1 is a block diagram illustrating an internal configuration of an embodiment of a delay adaptive scheduling apparatus according to a traffic type based on a conventional asynchronous transmission mode.

Referring to the drawings, the delay-adaptive scheduling apparatus 100 according to the traffic type based on the asynchronous transmission mode, the scheduling unit 110, the storage unit 130, the output unit 150, the input / output management unit 170, and the control unit It consists of 190.

The scheduling unit 110 classifies the cells inputted from the exchanger into a classification unit 113 and a classification unit 113 that classify the input cells according to a change in the characteristics of the traffic and the traffic type so as to fit the originally contracted traffic. It is composed of a generation unit 115 for generating service information for each cell. The service information is displayed as a tag in a cell, and for a cell of a constant bit rate (CBR) type, it includes traffic type, priority bit, service end time, and the like. Rt-VBR (real-time variable bit rate) and nrt- For cells of non-real-time variable bit rate (VBR), available bit rate (ABR) and unspecified bit rate (UBR) types, it includes traffic type, priority bits, service end time, and points of shared memory. Here, the service end time is a time set to guarantee the QoS for each cell, and means a time when the service is completed and a time required for the cell to be serviced. The service information generated by the generator 113 is output to the controller 190.

The storage unit 130 stores a cell in which the service information is generated in the scheduling unit 110, a buffer 133 in which a cell of a traffic type to which a fixed bandwidth is allocated, such as CBR, and rt-VBR and nrt-VBR. The shared memory 135 stores cells of traffic types to which variable bandwidths such as ABR and UBR are allocated.

The output unit 150 includes a cell reader 155 that reads a cell whose service is determined by the controller 190, and outputs the cell read by the cell reader 155 to the ATM switch 200. When outputting the cell from the output unit 150 to the ATM switch 200, the service information generated for each cell is discarded. The control unit 190 notifies the output state of the cell to the input / output management unit 170.

The input / output management unit 170 compares the occupancy capacity of the storage unit 130 with a preset threshold value and adjusts the occupancy capacity of the storage unit 130 to be less than the threshold value. The input cell counting unit 173 for notifying the buffer control unit 175 and the output cell counting unit 177 for counting the cells output from the output unit 150 and completing the service and notifying the buffer control unit 175. do.

The input cell coefficient unit 173 receives the input state of the cell from the scheduling unit 110 and notifies the buffer control unit 175 of the input cell coefficient value in which the number of input cells is increased. At this time, the input cell counting unit 173 may be configured to count the cells of the CBR traffic and the remaining types of cells according to the traffic type of the cell. The output cell coefficient unit 177 receives information about the serviced cell from the controller 190 and notifies the buffer control unit 175 of the output cell coefficient value. In this case, like the input cell counting unit 173, the CBR traffic cells and the remaining types of cells may be counted.

The buffer controller 175 may determine the current occupancy of the storage 130 through the input cell coefficient value and the output cell coefficient value. If the occupancy of the storage unit 130 exceeds the threshold, the buffer controller 175 outputs a control signal to the scheduling unit 110 to block the input of the cell to the scheduling unit 110.

The control unit 190 checks the service end time for the cell to which the higher priority is assigned based on the investigation result of the investigation unit 193 and the investigation unit 193 according to the service information according to the service information. And a service determination unit 195 for determining whether or not a service is given to a cell having a lower priority compared to the service termination time of the service. In addition, the controller 190 controls operations of each component including the scheduling unit 110, the output unit 150, and the input / output management unit 170. The service decision unit 195 preferably repeats an operation of determining whether or not a service for a cell given a higher priority is not present in the storage unit 130 in which the lower priority given cell has not been determined. .

2 is a flowchart illustrating a process of generating service information in a delay adaptive scheduling apparatus according to a traffic type based on a conventional asynchronous transmission mode.

Referring to the flowchart of FIG. 2, when a cell is input to the scheduling unit 110, the classifier 113 classifies the cell according to the traffic type of the input cell (S310 to S315). The traffic type of the input cell includes at least one of CBR, rt-VBR, nrt-VBR, ABR, and UBR.                         

If the input cell is CBR traffic, the scheduling unit 110 outputs a signal for the input cell coefficient unit 173 to increase the input cell coefficient value (S320). The input cell coefficient unit 173 transmits the input cell coefficient value to the buffer controller 175, and the buffer controller 175 compares the preset threshold value with the input cell coefficient value (S325). As a result of the comparison, when the input cell coefficient value is less than the threshold value, the generation unit 115 generates service information on the input cell in the form of a tag (S340). The generated service information is output to the controller 190 (S345), and the CBR traffic cell in which the generation of the service information is completed is stored in the buffer 133 (S350). If the input cell coefficient value exceeds the threshold, the flow of new UBR traffic cells is blocked (S330), and the traffic rate of the ABR traffic cell is adjusted (S335).

Meanwhile, when the traffic type of the input cell is not CBR traffic, the classification unit 113 sequentially checks whether VBR (rt-VBR and nrt-VBR), ABR, and UBR traffic are present (S305 to S315). If the input cell is one of VBR (rt-VBR and nrt-VBR), ABR, and UBR, the scheduling unit 110 outputs a signal for causing the input cell coefficient unit 173 to increase the input cell coefficient value ( S355).

The input cell coefficient unit 173 transmits the input cell coefficient value to the buffer controller 175, and the buffer controller 175 compares the preset threshold value with the input cell coefficient value (S360). As a result of the comparison, if the input cell coefficient value is less than the threshold value, the generation unit 115 records the field address of the shared memory 135 in which the input cell is stored (S375), and the service information for the input cell is in the form of a tag. To generate (S380). The generated service information is output to the control unit 190 (S385), the VBR (rt-VBR and nrt-VBR) in which the generation of the service information is completed, and the ABR and UBR traffic cells are stored in the shared memory 135 (S390). . If the input cell coefficient value exceeds the threshold, the flow of new UBR traffic cells is blocked (S365), and the traffic rate of the ABR traffic cells is adjusted (S370).

3 is a flowchart illustrating a process of determining a cell to be serviced according to service information in a delay adaptive scheduling apparatus according to a traffic type based on a conventional asynchronous transmission mode.

을, 해당 CBR 트래픽 유형의 셀에 대한 서비스 종료시간에서 다음 셀을 서비스하기 위한 시스템 대기시간을 뺀 값인

와 비교한다(S415). Referring to the flowchart of FIG. 3, the research unit 193 checks whether a cell of the CBR traffic type exists in the buffer 130 based on the service information (S400). If a cell of the CBR traffic type exists in the buffer 130, the service decision unit 195 may be a time required to perform the scheduling process once.

Is the service end time for a cell of that CBR traffic type minus the system latency for serving the next cell.

It is compared with (S415).

이면, 제어부(190)는 해당 CBR 트래픽 유형의 셀을 버퍼(130)로부터 독출하여 ATM스위치(200)로 출력하도록 하는 제어신호를 출력부(150)로 출력하며, 이에 따라 해당 셀은 ATM스위치(200)로 출력된다(S420). 출력셀계수부(177)는 제어부(190)로부터 CBR 트래픽 유형의 셀이 출력되었음을 통보 받으면, 서비스되어야 하는 전체 CBR 유형의 셀에서 출력셀을 감하고 변경된 출력셀계수값을 버퍼제어부(175)로 전송한다(S425). 버퍼제어부(175)는 이에 따라 현재 버퍼(330)의 점유용량을 파악할 수 있다. Comparison results

In this case, the controller 190 outputs a control signal to the output unit 150 to read the cell of the corresponding CBR traffic type from the buffer 130 and output it to the ATM switch 200. 200 is output (S420). When the output cell coefficient unit 177 is informed by the controller 190 that the CBR traffic type cell is output, the output cell coefficient is subtracted from the entire CBR type cell to be serviced, and the changed output cell coefficient value is transferred to the buffer controller 175. It transmits (S425). The buffer controller 175 may thus determine the occupancy of the current buffer 330.

이면, 조사부(193)는 서비스정보를 기초로 하여 공유메모리(135)에 VBR 트래픽 유형의 셀이 존재하는가를 검사한다(S405). 공유메모리(135)에 VBR 트래픽 유형의 셀이 존재하면, 조사부(193)는 VBR 트래픽 유형의 셀이 실시간 서비스를 요구하는지 여부, 즉 rt-VBR 및 nrt-VBR 여부를 확인한다(S430). 제어부(190)는 해당 셀이 rt-VBR 트래픽 유형의 셀이면 출력될 셀의 필드 어드레스를 기록하는 곳에 해당 셀에 대한 필드 어드레스를 기록한다(S435). On the other hand, if there is no cell of CBR traffic type,

On the other hand, the research unit 193 checks whether a cell of the VBR traffic type exists in the shared memory 135 based on the service information (S405). If the cell of the VBR traffic type exists in the shared memory 135, the investigator 193 checks whether the cell of the VBR traffic type requires real-time service, that is, whether rt-VBR and nrt-VBR (S430). If the corresponding cell is a cell of the rt-VBR traffic type, the controller 190 records the field address of the corresponding cell at a location where the field address of the cell to be output is recorded (S435).

The service determination unit 195 determines whether or not a service is provided to a corresponding cell through the same process as in operation S415, and accordingly, the control unit 380 outputs a control signal for outputting a field address for the cell whose service has been determined. And outputs (S440). The output unit 150 reads the cell from the shared memory 135 using the address received from the controller 190 and outputs the corresponding cell to the ATM switch 200 (S445). When the output cell coefficient unit 177 is informed by the controller 190 that the cell of the rt-VBR traffic type is output, the output cell coefficient is subtracted from all cells except the CBR type cell to be serviced and the changed output cell coefficient value is buffered. The controller 175 transmits the data to the control unit 175 (S450). The buffer controller 175 may thus determine the occupancy of the current buffer 130.

이 해당 rt-VBR 트래픽 유형의 셀에 대한 서비스 종료시간에서 다음 셀을 서비 스하기 위한 시스템 대기시간을 뺀 값인

보다 작으면, 상기 S435단계 내지 S450단계와 동일한 과정을 거쳐 nrt-VBR 트래픽 유형의 셀에 대한 서비스가 이루어진다(S455 내지 S465 및 S450). 만약 상기 S460단계에서

이면, nrt-VBR 트래픽 유형의 셀에 대한 서비스를 제공하지 않고 곧바로 S410단계로 진행하게 된다.In step S430, the cell of the VBR traffic type is identified as a cell of the nrt-VBR traffic type, or the time required to perform the scheduling process once in step S440.

The service end time for a cell of this rt-VBR traffic type minus the system latency to service the next cell.

If smaller, the service for the cell of the nrt-VBR traffic type is performed through the same process as steps S435 to S450 (S455 to S465 and S450). If in step S460

If not, the service proceeds directly to step S410 without providing a service for the cell of the nrt-VBR traffic type.

When it is determined in step S410 that a cell of the ABR traffic type exists, whether to service is determined by the same process as that for the cell of the VBR traffic type described above (S470 to S480). If it is determined in step S410 that the cell of the ABR traffic type does not exist or the time required to perform the scheduling process once is a system waiting time for serving the next cell from the service end time for the cell of the ABR traffic type. If the value is smaller than the subtracted value, the controller 190 records the field address for the cell of the UBR traffic type in the place where the field address for the cell to be output is recorded (S485). The output unit 150 reads the corresponding cell from the shared memory 135 using the address input from the controller 190 and outputs the corresponding cell to the ATM switch (S490), and proceeds to step S450.

2 and 3 illustrate the generation of the service information and the cell service using the service information in one scheduling process, this is for convenience of explanation, and the generation and service of the service information shown in FIGS. 2 and 3 are illustrated. Cell service using information is repeatedly performed.                         

However, the scheduling algorithm newly solved the problem of causing a waste of bandwidth to guarantee the end-to-end delay boundary where time-sensitive traffic is required by newly proposing a delay adaptation parameter, but it is not a parameter suitable for the traffic type. The problem is that you are using a fixed fixed parameter. As a result, when focusing on time-sensitive traffic, the performance correction for the average delay value for loss-sensitive traffic is insignificant, and when focusing on loss-sensitive traffic, loss occurs in time-sensitive traffic. This happens. Therefore, the conventionally proposed method does not guarantee all the inherent characteristics of each traffic type.

The present invention has been made to solve the above problems, and an object of the present invention, each traffic in the delay-adaptive scheduling according to the traffic type based on the asynchronous transmission mode to ensure the QoS and fair transmission suitable for each traffic type It is to provide a delay adaptive scheduling method and apparatus according to the traffic type based on the asynchronous transmission mode that can improve the overall performance by using different delay parameters according to the type.

Delay adaptive scheduling method according to the asynchronous transmission mode-based traffic type according to the present invention for achieving the above object, (a) to classify the cell according to the traffic type to include the traffic type, service priority, service end time Generating service information, (b) setting a system waiting time for serving a next cell according to the traffic type, and (b) providing service for the cell based on the service information and the system waiting time Determining, and (c) outputting the cell for which the service is determined.

The step (a) may include: (a1) classifying the cell according to traffic type, (a2) generating the service information, and (a3) storing the cell and the service information. desirable.

In step (c), (c1) examining the presence or absence of each traffic type according to the service information, and (c2) based on the result of the investigation in step (c1), to the cell to which a higher priority is assigned. Determining whether to service the cell to which a lower priority is given by comparing the time obtained by subtracting the system waiting time from the service ending time for the cell with the service ending time for the whole cell, and (c3) Outputting a storage address of the cell in which a service is determined in determining whether to provide a service, and for the cell to which a higher priority is assigned if the lower-priority cell in which a service is determined does not exist. It is preferable to repeat the steps (c1) to (c3). Preferably, the method further comprises the step of adjusting the occupation capacity of the storage means in which the cell is stored to be less than the threshold value by comparing with the preset threshold value.

On the other hand, the delay-adaptive scheduling apparatus according to the traffic type based on the asynchronous transmission mode according to the present invention, service information including the traffic type, service priority, service end time, and system waiting time by classifying cells according to traffic type A scheduling unit for generating a storage unit, a storage unit for storing the cell in which the service information is generated, an output unit for reading and outputting the cell whose service is determined from the storage unit, and a next cell according to the service information and the traffic type. And a control unit for outputting a control signal to the output unit to determine whether to service the cell and to read and output the cell stored in the storage unit, based on a system waiting time for servicing the system.

Preferably, the apparatus further includes an input / output management unit configured to count the cells input from the scheduling unit and the cells output from the output unit to manage input and output states of the cells. The control unit may further include: an investigation unit for investigating the presence or absence of each traffic type according to the service information, and the service waiting time at the service end time for the cell to which a higher priority is assigned based on an investigation result of the investigation unit; And a service determination unit which determines whether or not a service is provided to the cell given a lower priority by comparing the time subtracted from the service termination time of the entire cell, and outputs the storage address of the cell where the service is determined. It is preferable to output negative.

Hereinafter, with reference to the drawings will be described the present invention in more detail.

The present invention will be described with reference to the delay adaptive scheduling apparatus according to the traffic type based on the conventional asynchronous transmission mode shown in FIGS. 1 and 2, but the same reference numerals refer to the same parts as those shown in FIGS. Quoted and quoted.

In addition, the delay adaptive scheduling method according to the traffic type based on the asynchronous transmission mode according to the present invention uses a delay adaptive scheduling apparatus according to the traffic type based on the asynchronous transmission mode as shown in FIG. Service information is generated by the illustrated process.

4 is a flowchart illustrating a delay adaptive scheduling method according to an asynchronous transmission mode based traffic type according to the present invention.

Referring to the flowchart, the research unit 193 checks whether a cell of the CBR traffic type exists in the buffer 133 in the storage unit 130 based on the service information (S500). If the cell of the CBR traffic type exists in the buffer 133, the service determination unit 195 sets a system waiting time for serving the next cell with respect to the cell of the CBR traffic type (S510).

는 CBR 트래픽 유형의 셀에 대하여 설정된 다음 셀을 서비스하기 위한 시스템 대기시간이다. here,

Is a system latency for serving the next cell set for a cell of CBR traffic type.

After setting the system wait time, the service decision unit 175 subtracts the time required to perform the scheduling process once from the service end time for the cell of the corresponding CBR traffic type minus the system wait time for serving the next cell. It is compared with (S515). This is expressed as follows.

는 스케줄링 과정을 한번 수행하는 데 소요되는 시간,here,

Is the time it takes to perform the scheduling process once,

은 해당 CBR 트래픽 유형의 셀에 대한 서비스 종료시간이며,

Is the service end time for a cell of that CBR traffic type.

는 다음 셀을 서비스하기 위한 시스템 대기시간을 의미한다.

Denotes a system waiting time for serving the next cell.

이면, 제어부(170)는 해당 CBR 트래픽 유형의 셀을 버퍼(133)로부터 독출하여 ATM 스위치(200)로 출력하도록 하는 제어신호를 출력부(150)로 출력한다. 이에 따라, 출력부(150)의 셀독출부(155)는 해당 셀을 ATM스위치(200)로 출력하여, CBR 셀 서비스를 수행한다(S520).Comparison results

In this case, the controller 170 outputs a control signal to the output unit 150 to read the cell of the CBR traffic type from the buffer 133 and output the cell to the ATM switch 200. Accordingly, the cell reader 155 of the output unit 150 outputs the corresponding cell to the ATM switch 200 to perform a CBR cell service (S520).

When the output cell coefficient unit 177 is informed by the controller 190 that the CBR traffic type cell has been output, the output cell coefficient value is changed by subtracting the output cell from all CBR type cells to be serviced, and the changed output cell coefficient value. Is transmitted to the buffer control unit 175 (S525). The buffer controller 175 may determine the occupancy of the current buffer 133 by referring to the transmitted output cell coefficient value, and the occupancy of the buffer 133 may have a predetermined threshold value (for example, 90% of the total capacity). Adjust to be less than).

이면, 조사부(193)는 서비스정보를 기초로 하여 공유메모리(135)에 VBR 트래픽 유형의 셀이 존재하는가를 검사한다(S505). 검사결과, 공유메모리(135)에 VBR 트래픽 유형의 셀이 존재하면, 조사부(193)는 VBR 트래픽 유형의 셀이 실시간 서비스를 요구하는지 여부, 즉 rt-VBR 및 nrt-VBR 여부를 검사한다(S530). On the other hand, the cell of the CBR traffic type does not exist in step 500, or in step 515

On the other hand, the investigator 193 checks whether the cell of the VBR traffic type exists in the shared memory 135 based on the service information (S505). As a result of the check, if the cell of the VBR traffic type exists in the shared memory 135, the investigator 193 checks whether the cell of the VBR traffic type requires real-time service, that is, whether rt-VBR and nrt-VBR (S530). ).

As a result of the check, if the cell of the VBR traffic type requires real-time service, the system latency is set as follows.

는 rt-VBR 트래픽 유형의 셀에 대하여 설정된 다음 셀을 서비스하기 위한 시스템 대기시간이다. here,

Is a system latency for serving the next cell set for a cell of the rt-VBR traffic type.

과, 해당 rt-VBR 트래픽 유형의 셀에 대한 서비스 종료시간에서 다음 셀을 서비스하기 위한 시스템 대기시간을 뺀 값인

를 비교한다(S545). After the setting of the system waiting time, the controller 170 records the field address for the corresponding cell at the place of recording the field address of the cell to be output (S540). After recording the field address, the time required for the service determination unit 195 to perform the scheduling process once

And the service end time for the cell of the corresponding rt-VBR traffic type minus the system latency for serving the next cell.

To compare (S545).

이면, 서비스결정부(195)는 해당 rt-VBR 트래픽 셀에 대한 서비스를 결정하고, 이에 따라 제어부(190)는 서비스가 결정된 셀에 대한 필드 어드레스를 출력하도록 하는 제어신호를 출력부(150)로 출력한다. 출력부 (150)는 제어부(190)로부터 입력받은 어드레스를 이용해 공유메모리(135)로부터 해당 셀을 독출하여 ATM 스위치(200)로 출력한다(S550). Comparison results

If so, the service determination unit 195 determines a service for the corresponding rt-VBR traffic cell, and accordingly, the control unit 190 outputs a control signal to the output unit 150 to output a field address for the cell for which the service is determined. Output The output unit 150 reads the corresponding cell from the shared memory 135 using the address received from the controller 190 and outputs the corresponding cell to the ATM switch 200 (S550).

When the output cell counting unit 177 is informed by the controller 190 that the cell of the rt-VBR traffic type is outputted, the output cell counting unit subtracts the output cell from all cells except the CBR type cell to be serviced and buffers the changed output cell counting value. The control unit 175 transmits the data to the control unit 175 (S555). The buffer controller 175 may thus grasp the occupation capacity of the current buffer 330.

이면, 시스템 대기시간을 다음과 같이 설정한다.In step S530, the cell of the VBR traffic type is identified as a cell of the nrt-VBR traffic type, or in step S540.

If so, set the system wait time as follows.

는 nrt-VBR 트래픽 유형의 셀에 대하여 설정된 다음 셀을 서비스하기 위한 시스템 대기시간이다. here,

Is a system latency for serving the next cell set for a cell of the nrt-VBR traffic type.

을 해당 nrt-VBR 트래픽 유형의 셀에 대한 서비스 종료시간에서 다음 셀을 서비스하기 위한 시스템 대기시간을 뺀 값인

와 비교한다(S570). After the setting of the system general time, the control unit 170 records the field address of the cell to be output in the recording place of the field address of the cell to be output (S565). After recording the field address, the time required for the service determination unit 195 to perform the scheduling process once

Is the service end time for a cell of that nrt-VBR traffic type minus the system latency to service the next cell.

Compared with (S570).

이면, 서비스결정부(195)는 해당 nrt-VBR 트래픽 셀에 대한 서비스를 결정하고, 이에 따라 제어부(190)는 서비스가 결정된 셀에 대한 필드 어드레스를 출력하도록 하는 제어신호를 출력부(150)로 출력하고, 출력부 (150)는 제어부(190)로부터 입력받은 어드레스를 이용해 공유메모리(135)로부터 해당 셀을 독출하여 ATM 스위치(200)로 출력한다(S575). Comparison results

If so, the service determination unit 195 determines a service for the corresponding nrt-VBR traffic cell, and accordingly, the control unit 190 outputs a control signal to the output unit 150 to output a field address for the cell for which the service is determined. The output unit 150 reads the corresponding cell from the shared memory 135 using the address received from the controller 190 and outputs the corresponding cell to the ATM switch 200 (S575).

When the output cell counting unit 177 is informed by the controller 190 that the cell of the nrt-VBR traffic type is outputted, the output cell counting unit subtracts the output cell from all cells except the CBR type cell to be serviced and buffers the changed output cell count value. The control unit 175 transmits the data to the control unit 175 (S555).

이면, nrt-VBR 트래픽 유형의 셀에 대한 서비스를 제공하지 않고, 시스템 지연시간을 다음과 같이 설정한다.If in step S570,

In this case, the system delay time is set as follows without providing a service for a cell of the nrt-VBR traffic type.

는 ABR 트래픽 유형의 셀에 대하여 설정된 다음 셀을 서비스하기 위한 시스템 대기시간이다.here,

Is a system latency for serving the next cell set for a cell of ABR traffic type.

After setting the system waiting time, the investigator 193 checks whether a cell of ABR traffic type exists in the shared memory 135 based on the service information (S585).

을 해당 ARB 트래픽 유형의 셀에 대한 서비스 종료시간에서 다음 셀을 서비스하기 위한 시스템 대기시간을 뺀 값인

와 비교한다(S595). If it is confirmed that the cell of the ABR traffic type exists, the field address for the corresponding cell is recorded at the place where the field address of the cell to be output is recorded (S590). After recording the field address, the time required for the service decision unit 175 to perform the scheduling process once

Is the service end time for a cell of that ARB traffic type minus the system latency to service the next cell.

It is compared with (S595).

이면, 서비스결정부(190)는 통해 해당 ARB 트래픽 셀에 대한 서비스 여부를 결정하고 이에 따라 제어부(190)는 서비스가 결정된 셀에 대한 필드 어드레스를 출력하도록 하는 제어신호를 출력부(150)로 출력하고, 출력부(150)는 제어부(190)로부터 입력받은 어드레스를 이용해 공유메모리(135)로부터 해당 셀을 독출하여 ATM 스위치(200)로 출력한다(S600). Comparison results

In this case, the service determination unit 190 determines whether to service the corresponding ARB traffic cell, and accordingly, the controller 190 outputs a control signal to the output unit 150 to output a field address for the cell for which the service is determined. The output unit 150 reads the corresponding cell from the shared memory 135 using the address received from the controller 190 and outputs the corresponding cell to the ATM switch 200 (S600).

When the output cell coefficient unit 177 is notified by the controller 190 that the cell of the ARB traffic type is output, the output cell coefficient is subtracted from all cells except for the CBR type cell to be serviced, and the buffer cell control unit changes the output cell coefficient value. 175) (S555).

이면, 제어부(190)는 출력될 셀에 대한 필드 어드레스를 기록하는 곳에 UBR 트래픽 유형의 셀에 대한 필드 어드레스를 기록한다(S605). If it is determined in step S585 that the cell of the ABR traffic type does not exist, or in step 595,

After that, the controller 190 records the field address for the cell of the UBR traffic type in the place where the field address for the cell to be output is recorded (S605).

The output unit 150 reads the corresponding cell from the shared memory 135 using the address received from the controller 190 and outputs the corresponding cell to the ATM switch 200 (S610). When the output cell coefficient unit 177 is notified by the controller 190 that a cell of the UBR traffic type is output, the output cell coefficient unit 177 subtracts the output cell from all cells except the CBR type cell to be serviced, and changes the output cell coefficient value to the buffer control unit ( 175) (S555).

를 다르게 설정함으로써, 상위 우선순위가 부여된 셀의 서비스 여유시간동안 하위 우선순위가 부여된 셀을 처리할 수 있으므로, 종래의 방식보다 동일한 시간 내에 많은 양의 데이터를 처 리할 수 있다.By this process, the average latency per cell can be reduced within the range that ensures the maximum traffic characteristics. That is, for each traffic type

By setting differently, since the lower priority cell can be processed during the service spare time of the higher priority cell, a larger amount of data can be processed within the same time than the conventional method.

Meanwhile, in the above-described embodiment, the cell service is generated using the service information and the service information in one scheduling process, but this is for convenience of explanation, and the cell service using the service information and the service information is repeated. Is performed.

As described above, according to the present invention, the idle bandwidth is maximized by providing different available bandwidths to different sources while guaranteeing QoS and fair transmission suitable for each traffic type of an input cell. Therefore, different delay parameters can be used to reduce the average delay per cell at the switch, thereby processing a large amount of data in the same amount of time, ultimately improving overall switch performance.

In addition, although the preferred embodiment of the present invention has been shown and described above, the present invention is not limited to the specific embodiments described above, but the technical field to which the invention belongs without departing from the spirit of the invention claimed in the claims. Of course, various modifications can be made by those skilled in the art, and these modifications should not be individually understood from the technical spirit or the prospect of the present invention.

Claims (7)

(a) classifying cells according to traffic types to generate service information including a traffic type, a service priority, and a service end time; (b) setting a system latency for serving a next cell according to the traffic type; (c) determining whether to serve the cell based on the service information and the system waiting time; And (d) outputting the cell for which a service is determined; In step (b), The delay adaptive scheduling method according to the traffic type based on the asynchronous transmission mode, characterized in that the system wait time is set differently for each traffic type. The method of claim 1, In step (a), (a1) classifying the cell according to traffic type; (a2) generating the service information; And (a3) storing the cell and the service information; and a delay adaptive scheduling method according to the asynchronous transmission mode based traffic type. The method of claim 1, Step (c) is, (c1) examining the presence or absence of each traffic type according to the service information; (c2) On the basis of the survey result of step (c1), the time obtained by subtracting the system wait time from the service end time for the cell to which a higher priority is given, and the service end time for the entire cell; Determining whether to service the cell to which the lower priority is compared; And (c3) outputting a storage address of the cell in which the service is determined in the determining whether the service is included; If the cell to which the lower priority has been determined does not exist, the steps (c1) to (c3) are repeated for the higher priority cell. Delay-adaptive scheduling method based on traffic type. The method of claim 1, And comparing the occupancy capacity of the storage means in which the cell is stored with a predetermined threshold value to adjust the occupancy capacity to be less than the threshold value. The delay according to the asynchronous transmission mode-based traffic type. Adaptive Scheduling Method. A scheduling unit classifying cells according to traffic types to generate service information including a traffic type, a service priority, a service end time, and a system waiting time; A storage unit which stores the cell in which the service information is generated; An output unit configured to read and output the cell whose service is determined from the storage unit; And Based on the service information and the system waiting time for serving the next cell according to the traffic type, a control signal for determining whether to serve the cell and reading and outputting the cell stored in the storage unit. And a control unit outputting the output unit. The control unit, The delay adaptive scheduling apparatus according to the traffic type based on the asynchronous transmission mode, characterized in that for setting the different system waiting time for each traffic type. The method of claim 5, According to the asynchronous traffic mode-based traffic type further comprises a; input and output management unit for managing the input and output state of the cell by counting the cell and the cell output from the output unit input to the scheduling unit Delay-adaptive scheduling device. The method of claim 5, The control unit, An investigation unit for examining the existence of each traffic type according to the service information; And On the basis of the survey result of the research unit, a lower priority is obtained by subtracting the service waiting time from the service ending time for the cell to which the upper priority is assigned, compared with the service ending time for the entire cell. And a service decision unit to determine whether to provide the service for the granted cell. Delay adaptive scheduling apparatus according to the asynchronous transmission mode-based traffic type, characterized in that for outputting the storage address of the cell determined the service to the output unit.

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