KR960003782B1 - Scheduling controller and its method of subscriber access device of isdn - Google Patents

Abstract

The scheduling controller is for controlling the output order of the ATM(asynchronous transfer mode) cells according to the grade of the quality of service. The scheduling controller comprises a virtual path identifier/virtual channel identifier(VPI/VCI) table(7) for providing QOS grade of input cell to a QOS grade identifier(2), a buffer level counter(8) for supervising a QOS buffer(3), a QOS grade discriminator(9) for discriminating grade of the input cell according to the input traffic of the QOS grade identifier(2), a buffer state comparator(10) for comparing status data sent from the QOS grade buffer(3), and a scheduling order generator(11) for generating the scheduling order according to the buffer status data and the QOS grade data.

Description

Scheduling Control Device and Method According to Service Quality Class of Broadband Comprehensive Telecommunication Network Subscriber Access Equipment

1 is a schematic diagram of a scheduling controller of the prior art.

2 is a schematic diagram of a scheduling controller according to the present invention.

3 is a conceptual diagram of generating sequence information.

4 is a state transition diagram of a scheduling controller.

5 is a flowchart illustrating a scheduling control method according to the present invention.

* Explanation of symbols for main parts of the drawings

1: Input buffer 2: QOS class identification unit

3: QOS grade buffer 4: Scheduler part

5: scheduling controller 6: connection state management unit

7: VPI / VCI Table Part 8: Buffer Level Counting Part

9: QOS class determination unit by VPI / VCI 10: Buffer status comparison unit

11: scheduling sequence generator

According to the present invention, a broadband subscriber access device configuring a broadband access network in a broadband integrated information network (B-ISDN) is a buffer used for each input terminal of an ATM (Asynchronous Transfer Mode) cell for each line and virtual connection inputted through a standard connection. Scheduling control device and method used to control the output order of ATM cells input by connection per line when multiplexing according to the status of FIFO and quality of service (QOS) level of each connection service It is about.

1 is a structural diagram of two existing scheduling controllers used in a general ATM multiplexer.

(a) is a polling type scheduling controller, in which multiple (n) input buffers and a scheduler are connected to each other. Each input buffer is sequentially connected to the scheduler to enter ATM cells from different input lines. Are stored in each input buffer, and the scheduling controller sequentially generates scheduling order information while observing the level of each input buffer. At this time, the input buffer with the empty cell operates by passing the output order of the ATM cell to the next buffer except in the sequential scheduling order.

(b) is a weighted round robin scheduling controller, which is connected to several (N) input buffers, buffers for each VPI / VCI (Virtual Path Identifier / Virtual Channel Identifier), and a scheduler. Referring to the operation of the scheduling controller, ATM cells stored in each input buffer store ATM cells in a separate buffer for each VPI / VCI according to a selection signal from the scheduling controller, and then allocated according to the bandwidth ratio for each VPI / VCI. The scheduling order information that is sequentially operated by the weight is generated, and the scheduler is controlled to output as many weighted cells as every output opportunity.

B-ISDN, which provides a variety of high-speed services, accepts audio, video and data subscriber services with various characteristics, connects to the network, uses sufficient resource sharing on the lines with high-speed bands, and establishes an appropriate communication network according to subscriber characteristics. In order to efficiently manage and support multimedia services and broadcasting and distribution services, a new type of subscriber access is required for efficient control of multi-connection, multi-party call function and distribution control function. In this need, the subscriber access network has emerged, and the required devices need multiplexing to accommodate such complex requirements and share sufficient resources. To this end, the subscriber's service requirements are accepted and the operator's efficient network management is provided. There is a need for a new scheduling controller. Currently, various types of scheduling controllers using statistical techniques for adopting ATM multiplexers have been proposed, but they are negotiated when establishing connection with each subscriber in B-ISND environment with various transmission characteristics such as variable bit rate and burst. There is a difficulty in providing satisfaction with the quality of service. In particular, the performance of the scheduling controller used in the multiplexing processing apparatus greatly affects the performance of the subscriber access device, and further, the performance of the entire communication system is severely degraded.

Accordingly, the present invention, which is devised to solve all the problems of the prior art, divides the grades according to the QOS of each service to reduce the cell loss rate and the cell delay rate in order to multiplex ATM cells according to the QOS of each service. The purpose of the present invention is to provide a scheduling control apparatus and method according to the QOS class of a broadband access network subscriber access device considering the buffer status in order to give priority to each grade and improve the cell loss rate.

In order to achieve the above object, the apparatus of the present invention, in the multiplexing processing unit of the broadband subscriber access device in the scheduling control device which is connected to the QOS class identification unit, QOS class buffer, the scheduler unit and the connection state management unit, each input terminal A VPI / VCI table that provides a classification criteria for QOS grades of incoming cells to the QOS grade identifier; Buffer level counting means for observing the state of said QOS grade buffer; QOS grade discrimination means for each VPI / VCI for determining a priority grade according to the state of the input traffic and the connection state from the QOS grade identifier; Buffer state comparison means for comparing the state information input for each QOS grade buffer; And scheduling order generating means for generating scheduling order information using the buffer status information and the QOS grade information.

In addition, the scheduling control method applied to the device configured as described above, if the cell to receive the input traffic information from the QOS class identification unit in the connection state management unit and transmits the connection configuration information, determine the QOS class of the cell and classify QOS class A first step of transmitting information to the scheduling order generating means (13); A second step of inputting buffer state information in the QOS grade buffer to determine whether the QOS grade classification information from the QOS grade discrimination means for each VPI / VCI is in the buffer pool frag state; A third step of prioritizing and returning the buffer if the buffer pool flag is set and the buffer pool counter is not a threshold and incrementing and increasing the threshold to reset and return the buffer pool counter; After performing the second step, finding a place where the buffer pool is located, setting a buffer pool frag, giving a priority to the corresponding buffer, and returning it; And a fifth step of performing a buffer pool and checking whether a cell exists in each QOS rank, sequentially giving priority to each rank buffer in which the corresponding cell exists, and returning the buffer pool. do.

Hereinafter, an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

2 is a schematic diagram of a scheduling control device according to the present invention QOS rating, 1 is an input buffer, 2 is a QOS class identification unit, 3 is a QOS class buffer, 4 is a scheduler unit, 5 is a scheduling controller, 6 Denotes a connection state management unit, 7 denotes a VPI / VCI table unit, 8 denotes a buffer level counting unit, 9 denotes a QOS class determination unit for each VPI / VCI, 10 denotes a buffer state comparison unit, and 11 denotes a scheduling sequence generator.

As shown in the figure, the present invention operates in connection with the QOS class identification unit 2, the QOS class buffer 3, the scheduler unit 4, and the connection state management unit 6 in the multiplexing processing unit of the broadband subscriber access device. The configuration is as follows.

The VPI / VCI table unit 7 which provides the QOS class classification criteria of the cell entering each input terminal to the QOS class identification unit 2, and the buffer level counting unit 8 which observes the state of the QOS class buffer 3 The state information input for each VPI / VCI QOS grade determination unit 9 and QOS grade buffer 3 that determine priority grades according to the state and connection state of the input traffic from the QOS grade identification unit 2 are stored. A buffer status comparison unit 10 to compare, and a scheduling order generation unit 11 to create the scheduling order information using the buffer status information and QOS class information.

Referring to FIG. 3, the function of the scheduling controller 5 will be described. The QOS class identification section 2 is used to generate the scheduling order information (e) to be used for the purpose of multiplexing. State information of the input traffic (b) received from the above), QOS parameter (i) which is information representing a different state for each connection received from the connection state management unit 6, connection weight information of the network operator, and the QOS grade buffer (3) The scheduling order information (e) is made using the buffer state information (c) input for each. Looking at the function and operation of each functional unit is as follows.

First, the VPI / VCI table unit 7 divides the ATM cells stored in the input buffers from the respective input lines into QOS grade buffers and stores them in the QOS grade buffer 3 for the QOS grade identification operation. A block that provides a QPI class table for each VPI / VCI when a look-up function is performed. The QOS class identification unit provides connection setting information related to a cell coming from each input in synchronization with a cell clock and a byte clock. (2) to pass.

The QOS class determination unit 9 for each VPI / VCI is responsible for the connection between the block and the scheduling controller in charge of network management and connection management, and when the connection is established between the subscriber and the network, the connection state management unit 6 connects to the corresponding connection. The QOS class identification table (bar) for each VPI / VCI is generated by receiving the relevant QOS parameter (child) and provided to the VPI / VCI table unit (7), and the QOS of the ATM cell inputted in each line In the process of identifying the class, input traffic information (B) received from the QOS class identification unit 2 and the QOS received from the connection state management unit 6 such as the input state of the cell for each VPI / VCI investigated and the location of the stored buffer. Priority information (Q) for each QOS buffer and VPI / VCI is created using the parameter (i), and the information is transferred to the scheduling order generator 11.

The buffer level counting section 10 observes buffer status signals (C) such as a buffer full signal, a buffer empty signal, and the like from each of the QOS class buffers 3. It functions to send to the buffer state comparison unit 10.

The buffer state comparator 10 determines the priority between the buffer state information inputted from the buffer level counting unit 8 and the case of the buffer pool and the buffer empty. When output to the monitoring the corresponding threshold value and transfers the information about this to the scheduling order generation unit (11).

The scheduling order generation unit 11 uses the QOS parameter (i) and the input traffic information (b) to ensure cell loss and cell delay characteristics according to the negotiated QOS. Receive priority information (Q) for each QOS buffer and VPI / VCI and buffer pool and threshold monitoring information from the buffer status comparison unit 10, and combine these two signals to create scheduling order information (E). . The scheduling order information (e) thus produced is sent to the scheduler 4 in accordance with the cell clock and the byte clock to control the cell multiplexing operation. In this case, the reason for giving priority to the buffered low priority service only by the threshold is to minimize the deterioration of the cell delay characteristic caused by the low priority buffer having the opportunity to output the cell first.

4 is a state transition diagram for explaining the operation of the scheduling controller 5 according to the QOS class proposed in the present invention.

When the connection is established, the operation of the scheduling algorithm is started from the initial mode 14, and then the state transitions to the service of the higher priority QOS class 15 having higher priority. At the same priority, according to the first-in, first-out principle, the buffer is maintained until the buffer is empty (15), but when the buffer becomes empty, the status is changed to the service of the lower QOS class (17). However, even if there is an upper QOS class 15 state, if there is a lower priority buffer in which the buffer is full, the state transitions to the buffer pool processing state 16. In this case (16), when the buffer releases the pool, if the number of cells to be served becomes a threshold value (assigned a different value for each QOS class), the state returns to the original state 15. Similarly, when a pull-in buffer is generated in the lower QOS class 17 state, the state transitions to the buffer pool processing state 16. In this manner, the scheduling controller 5 operates.

5 is a flowchart illustrating a scheduling control method according to the present invention.

The connection state management unit 6 obtains information on the presence or absence of the connection establishment, and if there is a connection establishment (18), receives input traffic information from the QOS class identification unit (19) (19) and if there is a cell to transmit (20) When / VCI matches the correct VPI / VCI value established (21), the QOS grade of the cell is checked and determined as a lookup table (22), and the QOS grade classification information (h) is determined by the scheduling sequence generator (11). Send to.

Input the buffer status information (C) in the QOS class buffer (3) (24, 25) and receive the QOS class classification information (H) from the QOS class discriminator 9 for each VPI / VCI (26) Check if this is set (27).

As a result of the investigation 27, if the buffer pool flag is set, the buffer pool counter is incremented (34), and if the pool counter is thresholded (35), if the pool counter is a threshold, the buffer pool counter is reset and returned (36) If the counter is not a threshold, the buffer is prioritized and returned (33).

As a result of the investigation (27), if the buffer pool freck is not set, it is examined whether there is a buffer pool (28). If there is a pool, the buffer pool freck is set (32), and the priority is given to the buffer and returned (33). If there is no place in the buffer pool, clear the buffer pool flag and buffer counter (29) and check the existence of cells in the priority buffer (30) .If there are cells in the priority buffer, the priority buffers are given priority and returned in order. If there is no cell in the priority buffer (31), if there is a cell in the second buffer (37), if the cell exists in the second buffer, it sequentially gives priority to the second buffers and returns (28). If there is no cell in the second-order buffer, then the existence of the cell in the third-order buffer is checked (39). If the cell exists in the third-order buffer, the priority is given to the third-order buffers sequentially and returned (40). 4th rank buffer if there are no cells in the rank buffer If there is a cell in the 4th priority buffer, priority is given to the 4th priority buffers sequentially, and if it is not returned, the process ends (42). The scheduling order information (e) generated through the transmission is transmitted to the scheduler unit 4.

As described above, the present invention divides a cell inputted into a subscriber access device into four priorities, stores them in an independent buffer, and outputs them according to the service grade information related to the input cell, the state of the buffer, and the network manager's requirements Creates order information and outputs the cells from high priority according to this order to First-Come-First-Service, and the buffer is full to prevent the increase of cell loss rate caused by low priority. By designing the cells as many thresholds as possible by giving the highest priority to the input traffic, the cell loss rate is improved by improving the cell delay characteristics for services with isochronous traffic and reducing the probability of buffer overflow. Has the effect of improving.

Claims (3)

In the multiplexing processing unit of the broadband subscriber access device, a service quality (hereinafter referred to as QOS) class identification unit 2, a QOS class buffer 3, a scheduler unit 4, and a connection state management unit 6 are connected and operated. 1. A DULTING control apparatus, comprising: a VIP / VCI (Virtual Path Identifier / Virtual Channel Identifier) table (7) for providing the QOS class classification criteria of a cell entering each input terminal to the QOS class identification unit (2); Buffer level counting means (8) for observing the state of said QOS grade buffer (3); QOS grade determination means for each VPI / VCI for determining the priority grade according to the state of the input traffic and the connection state from the QOS grade identification section 2; Buffer state comparing means (10) for comparing the state information input for each of the QOS grade buffers (3); And a scheduling order generating means (11) for generating scheduling order information using the buffer status information and the QOS rating information. It is connected to the QOS class identification section (2), the QOS rating buffer (3), the scheduler section (4) and the connection state management section (6), and operates in the VPI / VCI table (7), buffer level counting means (8), and VPI. In the scheduling control method applied to the scheduling control device having a QOS grade determining means (9), buffer status comparison means (10), scheduling order generating means (11) for each / VCI, the connection state management unit (6) If the cell to receive the input traffic information from the QOS class identification unit 2 to transmit the connection setting information to determine the QOS class of the cell and transmits the QOS class classification information (h) to the scheduling order generating means (13) First steps 18 to 23; Inputting the buffer status information (c) in the QOS rating buffer (3) to check whether the QOS rating classification information (h) from the QOS rating determination means (9) for each VPI / VCI determines whether the buffer pool fragment is set. Second steps 24 to 27; A third step (34 to 36, 33) of resetting and returning the buffer buffer counter if the buffer buffer is set and the buffer pool counter is not a threshold, prioritizing and returning the buffer and increasing the threshold; A fourth step (28, 32, 33) of performing a second step (24 to 27), finding a place in the buffer pool, setting a buffer pool flag, and then assigning and returning a priority to the corresponding buffer; And performing a fourth step 28, 32, 33, and if there is a buffer pool, checking whether a cell exists in each QOS rank, sequentially giving priority to each rank buffer in which the corresponding cell exists, and returning the fifth step. 29 to 31, 37 to 42, characterized in that the scheduling control method according to the QOS class of the broadband access information subscriber network access device. 5. The method of claim 2, wherein the fifth steps 29 to 31 and 37 to 42 clear the buffer pool frck and the buffer counter and, if there are cells in the priority buffer, prioritize and return the priority buffers sequentially. If there is no cell in the priority buffer, the first process (29 to 31) to check the presence of the cell in the second buffer; A second step (37, 38) of sequentially giving priority to the second priority buffers and returning the cells if the cells exist in the second priority buffer, and checking whether a cell exists in the next third priority buffer if there is no cell in the second priority buffer; And if there is a cell in the 3rd priority buffer, priority is given to the 3rd priority buffers and returned.If there is no cell in the 3rd priority buffer, the existence of the cell in the 4th priority buffer is checked. And a third step (39 to 42) of sequentially assigning and returning priority buffers to the ranking buffers.