KR100249514B1 - Method for cdp queueing bandwidth dynamic allocation in atm switches - Google Patents

Abstract

1. TECHNICAL FIELD OF THE INVENTION

The present invention relates to a cell delay priority queuing bandwidth dynamic allocation method.

2. The technical problem to be solved by the invention

According to the present invention, the cell delay priority of each cell input to the switch is classified into four types, and the asynchronous transfer mode switch dynamically allocates the dynamic queuing bandwidth for the buffer memory according to each cell delay priority according to traffic conditions. To provide cell delay priority queuing bandwidth dynamic allocation method.

3. Summary of Solution to Invention

The present invention includes a first step of configuring a buffer management attribute for each cell delay priority type that can be initialized during system operation; A second step of adjusting a buffer memory area that can be occupied by each cell type during system operation according to a characteristic of the configured attribute upon receiving the cell delay priority control request signal; And a third step of controlling traffic according to a service threshold for each cell delay priority type for the buffer size.

4. Important uses of the invention

The present invention is used in ATM switches and the like.

Description

Cell Delay Priority Queuing Bandwidth Dynamic Allocation Method in Asynchronous Transfer Mode Switch

The present invention classifies the cell delay priority (CDP: Cell Delay Priority) of each cell input to the switch to implement the cell delay priority processing function in an Asynchronous Transfer Mode (ATM) switch. The present invention relates to a cell delay priority queuing bandwidth dynamic allocation method for improving the quality of service (QoS) of an ATM system by allocating a dynamic queuing bandwidth for a buffer memory for each cell delay priority.

To date, there are no techniques for dealing with cell delay priorities using buffer memory management attributes in ATM switches.

Conventionally, multi-frame strategy based congestion management (S. Jarnaloddin et al., US, registration number 5,050,161, 1991) scheme and ATM cell scheduler (Jinathan W. Byrn et al., US, registration) as a technique for performing the cell delay priority control function No. 5,533,020, 1996).

First, the congestion management method based on a multi-frame strategy demultiplexes each multiplexed cell into required service types, queues them in a specific buffer memory allocated to each service type, and then stops-stops each service queue. -GO) The cell delay priority of each cell is controlled by performing output service control through the protocol.

However, the congestion management method based on the multi-frame strategy, unlike the effect that can be obtained by dynamically operating the size of the usage area for each service type in a constant buffer memory, requires a fixed and significant buffer memory size for all services. There is a problem that it takes a lot of time to control the overall cell delay priority by adopting a STOP-AND-GO protocol.

Meanwhile, the ATM cell scheduler method allocates link bandwidth to guarantee quality of service (QoS) for multiple virtual channels destined for the same output link. By using various parameters (ie, current transmission time (CTT), final cell transmission time (LCTT), peak cell rate (RP), and maximum number of virtual channels (MC)) to perform output control for each service type of As the amount of computation is enormous, parallelization and pipeline of the controller processing procedures must be accompanied.

However, since this method is also performed after first queuing the input cell, there is a problem in that a significantly larger buffer memory exists than the method of controlling before queuing.

In order to solve the above problems, the present invention classifies the cell delay priorities of each cell input to the switch into four types, and the dynamic queuing bandwidth for the buffer memory according to each cell delay priority. The purpose of the present invention is to provide a cell delay priority queuing bandwidth dynamic allocation method for improving the service level while increasing the memory utilization in the asynchronous transfer mode switch that is dynamically allocated.

1 is a structural diagram of a buffer management attribute for each cell delay priority used in the present invention.

2 is a flowchart illustrating an embodiment of a method for dynamically allocating queuing bandwidth for each type of cell delay priority according to the present invention.

3 is a detailed flowchart illustrating a process of configuring a buffer management attribute for each cell delay priority type according to the present invention.

4 is a detailed flowchart illustrating a buffer allocation dynamic management process for each cell delay priority type according to the present invention.

5 is a detailed flowchart illustrating a service threshold management process for each cell delay priority type according to the present invention.

6 is a traffic distribution diagram of input cells according to cell delay priority types according to an embodiment of the present invention.

7A and 7B show input cell queuing results of the occupancy and open buffer management attribute of type 0 (TYPE-0) in accordance with an embodiment of the present invention.

8A and 8B show input cell queuing results of the occupancy and open buffer management attribute of type 1 (TYPE-1) according to an embodiment of the present invention.

9A and 9B show input cell queuing results of four types of occupancy and open buffer management attributes in accordance with an embodiment of the present invention.

According to an aspect of the present invention, there is provided a cell delay priority queuing bandwidth dynamic allocation method applied to an asynchronous transfer mode switch, the method comprising: configuring a buffer management attribute for each cell delay priority type that can be initialized during system operation; step; A second step of adjusting a buffer memory area that can be occupied by each cell type during system operation according to a characteristic of the configured attribute upon receiving the cell delay priority control request signal; And a third step of controlling traffic according to a service threshold for each type of cell delay priority for the buffer size.

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

1 is a structure diagram of a buffer management attribute for each cell delay priority used in the present invention.

The buffer management attribute structure by cell delay priority consists of occupied and open attributes.

There are four cell delay priority types 100 constituting a header of each cell, and cells having the same type are stored in a buffer area of a corresponding type virtually separated in a shared buffer memory.

For example, a cell delay priority value is detected from a cell inputted using multiplexed shared buffer memory but the counter is increased for each type, and the buffer value is reduced while the cell is outputted from the buffer memory. By virtually limiting the maximum number of cells that can be stored in memory, the shared buffer is virtually divided into buffer memories by cell delay priority.

The occupied buffer management attribute 110 prioritizes its own cell delay even in the unused area of another group buffer in which the buffer management open attribute 120 is set, in addition to the buffer initial value allocated to its group for the buffer memory for each of four cell delay priorities. It can be incorporated into the rank buffer area.

In this case, the buffer management open attribute 120 may incorporate only the buffer size (ie, unused buffer size) obtained by subtracting the used buffer size due to cell occupancy from the set initial value buffer size of another group.

The role of the buffer management open attribute 120 is to provide another group with respect to the area already used (that is, the subtracted buffer size storing the cell) from the initial buffer size allocated to the cell delay priority group. Allow.

Referring to FIG. 1, cell delay priority types may be classified into type 0 (TYPE0), type1 (TYPE1), type2 (TYPE2), and type3 (TYPE3). Where each type has a value of zero or one.

For example, an attribute of 0 means not to use the setting, and an attribute of 1 means to allow the buffer to be occupied or to open the buffer, depending on the type of the attribute.

2 is a flowchart illustrating an embodiment of a method for dynamically allocating queuing bandwidth for each type of cell delay priority according to the present invention.

The present invention provides a buffer management attribute configuration block by cell delay priority type, a buffer allocation dynamic management block by cell delay priority type, and cell delay in order to allocate dynamic queuing bandwidth for each cell delay priority type of a cell header input from an ATM switch. It consists of service threshold management block for each priority type.

First, a buffer management attribute for each cell delay priority type is configured when necessary during system startup or operation (201).

In the standby state (202), when receiving a cell delay priority control request signal generated when a normal ATM cell is input to the switch (203), the buffer memory corresponding to the cell delay priority type detected from the cell The current size of is calculated using the buffer management attribute (204).

Thereafter, after performing traffic control such as cell loss processing according to the upper and lower threshold values for the buffer size (205), it is determined whether to terminate (206), and repeatedly functions in the standby state as long as the input cell exists. Do this.

3 is a detailed flowchart illustrating a process of configuring a buffer management attribute for each cell delay priority type according to the present invention.

First, it is determined whether a system reset has occurred by power reset or manual reset during operation at system startup.

As a result of the determination, when the reset occurs, the switch-related processor requests an initial value of the buffer size for each cell delay priority type (302).

Then, in the standby state (303), if an initial value is reported from the processor (304), it is analyzed whether or not the initial value that is acceptable in the buffer memory constitutes (305).

As a result of the analysis, if the initial value is allowed, the buffer management register is initialized with the reported initial value, and together with the reported buffer management attribute, its attribute register is initialized (306), and the system is shut down.

As a result of analysis, after initializing each register with the initial value and the buffer management attribute of the basic value which it owns, the system is shut down.

As a result of the determination, if no reset occurs, the system is immediately shut down.

4 is a detailed flowchart illustrating a buffer allocation dynamic management process for each cell delay priority type according to the present invention.

First, a cell delay priority type is analyzed from an input cell header (401).

The analysis shows that if the priority type is type 0 (TYPE-0), the occupancy and open attribute values of this type are not set, so the buffer size (Q ₀ ) given as the initial value is assigned to the buffer size of type 0 (TYPE-0). (NQ ₀ = Q ₀ ) 402, and the system ends. Here, NQ ₀ represents a buffer memory size of type 0 (TYPE-0) calculated by cell input, and Q ₀ represents an initial value for a buffer memory size of type 0 (TYPE-0) of a buffer management attribute.

According to the analysis, if the priority type is TYPE-1, the occupancy attribute is not set but the open attribute is set for the buffer, so it is determined how much of the buffer area is already occupied by other type groups. shall.

The order of calculation is to analyze the buffer usage status of Type 2 (TYPE-2), which sets the occupancy attribute but does not open its own buffer, and then analyzes the usage of the type 3 (TYPE-3) with both occupancy and open attributes set. By analyzing the buffer usage state in conjunction, it is possible to finally calculate the buffer size allocated or remaining in the type 1 (TYPE-1) (403 to 415).

The calculation procedure is as follows.

First, it is determined whether the actual buffer memory size U _{2 in} which the type 2 cells are stored is larger than the initial value Q ₂ for the buffer memory size of the type 2 of the buffer management attribute (Type 2). 403).

As a result, if U ₂ is greater than Q ₂ , the actual buffer memory size U ₃ storing the cells of type 3 (TYPE-3) is the initial value for the buffer memory size of the type 3 (TYPE-3) of the buffer management attribute. Q ₃ ) is greater than (404).

If U ₃ is greater than Q ₃ , then U ₂ minus Q ₂ (U ₂ -Q ₂ ) and U ₃ minus Q ₃ (U ₃ -Q ₃ ) plus ((U ₂ -Q ₂₎ It is analyzed whether () + (U ₃ -Q ₃ )) is larger than the memory size E ₁ in which the cell is not stored in the buffer memory Q ₁ (405).

As a result, when ((U ₂ -Q ₂ ) + (U ₃ -Q ₃ )) is greater than E ₁ , after determining the updated buffer allocation size (NQ ₁ = U ₁ ) 406, the system terminates. Where U ₁ represents the actual buffer memory size where cells of type 1 (TYPE-0) are stored.

Analysis shows that if E ₁ is greater than ((U ₂ -Q ₂ ) + (U ₃ -Q ₃ )), then the size of the updated buffer allocation is determined (NQ ₁ = U ₁ + (E ₁ -((U ₂ -Q)). ₂ ) + (U ₃ -Q ₃ ))))) 407, the system shuts down.

On the other hand, if Q ₃ is greater than U ₃ , it is determined whether (U ₂ -Q ₂ ) is greater than (E ₁ + E ₃ ) (408). Here, E ₃ represents the memory size in which the cell is not stored in the buffer memory Q ₃ .

As a result, if (U ₂ -Q ₂ ) is greater than (E ₁ + E ₃ ), after determining the updated buffer allocation size (NQ ₁ = Q ₁ ) (409), the system terminates.

If (E ₁ + E ₃ ) is greater than (U ₂ -Q ₂ ), determine the updated buffer allocation size (NQ ₁ = U ₁ + ((E ₁ + E ₃ )-(U ₂ -Q ₂₎ ))) 410, shut down the system.

As a result of the previous determination, if Q ₂ is greater than U _2, it is analyzed whether U ₃ is greater than Q ₃ (411).

Analysis, and U ₃ to a check is greater than E ₁ is greater than _{Q 3 (U 3 -Q 3)} (412).

As a result of the check, if (U ₃ -Q ₃ ) is greater than E ₁ , after determining the updated buffer allocation size (NQ ₁ = U ₁ ) 413, the system terminates.

If E ₁ is greater than (U ₃ -Q ₃ ), after determining the updated buffer allocation size (NQ ₁ = U ₁ + (E _1- (U ₃ -Q ₃ ))) (414), the system shuts down. do.

As a result of analysis, if Q ₃ is greater than U ₃ , after determining the updated buffer allocation size (NQ ₁ = U ₁ ) 415, the system terminates.

As a result of the analysis, if the priority type is TYPE-2, the buffer usage state of TYPE-3 is analyzed to determine its own buffer size (416 to 420).

This procedure is as follows.

First, it is determined whether U ₃ is greater than Q ₃ (416).

If, and U ₃ the analysis if it is greater than the E ₁ is greater than _{Q 3 (U 3 -Q 3)} (417).

As a result, when (U ₃ -Q ₃ ) is greater than E ₁ , after determining the updated buffer allocation size (NQ ₂ = Q ₂ ) 418, the system terminates. Here, NQ ₂ represents an initial value for a buffer memory size of type 2 (TYPE-2) calculated again by cell input.

If E is greater than (U-Q), after updating the buffer allocation size (NQ = Q + (E- (U-Q))) 420, the system terminates.

On the other hand, if Q ₃ is greater than U ₃ , after determining the updated buffer allocation size (NQ ₂ = Q ₂ + E ₁ + E ₂ ) 419, the system ends. Here, E ₂ represents the memory size in which the cell is not stored in the buffer memory Q ₂ .

As a result of the analysis, if the priority type is TYPE-3, the buffer usage status of the TYPE-2 is analyzed to determine its buffer size (421 to 425).

This procedure is as follows.

First, it is determined whether U ₂ is greater than Q ₂ (421).

Determination result, U is a _divalent analyzed is larger than the (E ₁ + E ₃₎ is greater than _{Q 2 (U 2 -Q 2)} (422).

As a result, when (U ₂ -Q ₂ ) is greater than (E ₁ + E ₃ ), after determining the updated buffer allocation size (NQ ₃ = U ₃ ) (423), the system terminates. Here, NQ ₃ represents an initial value for a buffer memory size of type 3 (TYPE-3) that is calculated again by cell input.

Analysis shows that if (E ₁ + E ₃ ) is greater than (U ₂ -Q ₂ ), then the size of the updated buffer allocation is determined and then (NQ ₃ = U ₃ + ((E ₁ + E ₃ )-(U ₂ -Q ₂₎ ))) 424, the system shuts down.

As a result of determination, when Q ₂ is larger than U ₂ , after determining the updated buffer allocation size (NQ ₃ = Q ₃ + E ₁ ) 425, the system ends.

5 is a detailed flowchart illustrating a process of managing service thresholds by cell delay priority type according to the present invention. The function of determining service thresholds by cell delay priority type and comparing current buffer use status of the corresponding type determines the presence or absence of cell loss. Indicates.

First, it is determined whether the buffer use size (ie, cell storage buffer size) of the same group as the cell delay priority (CDP) type from the input cell header is less than the upper limit threshold for that type (501).

If the CDP type cell storage buffer size is smaller than the upper limit threshold for the type, it is analyzed whether the CDP type cell storage buffer size is smaller than the lower limit threshold (502).

As a result of the analysis, if the cell storage buffer size of each CDP type is less than the upper and lower thresholds, the input cells are stored in the corresponding CDP group cell buffer (504).

If the size of the cell storage buffer for each CDP type is between the upper and lower thresholds, the lower threshold exceeded status is reported to the processor for failover (503), and the corresponding CDP group cell buffers can be stored in the cell buffer of type. After storing the input cell in 504, the system is shut down.

On the other hand, if the cell storage buffer size for each CDP type is greater than or equal to the upper threshold for that type, the upper threshold exceeded status is reported to the processor for failover (505), and the input cell is discarded in the corresponding CDP group cell buffer. After that (506), the system shuts down.

6 is a traffic distribution diagram of input cells according to cell delay priority types according to an embodiment of the present invention.

Each CDP traffic is multiplexed on the same data transmission line.

Q ₁ , Q _2, Q ₃ , and Q ₄ represent buffer memory initial values allocated to each cell delay priority (CDP-0, CDP-1, CDP-2, and CDP-3) traffic (600, 610, 620, and 630).

Lines broken on the time axis indicate traffic amounts at respective points in time for each CDP (601, 611, 621, and 631).

7A and 7B illustrate input cell queuing results of the occupancy and open buffer management attribute of type 0 (TYPE-0) according to an embodiment of the present invention.

Referring to FIG. 7A, "700" represents a cell queuing state in which all CDP type buffer management attributes are set to type 0 (TYPE-0).

Referring to Fig. 7B, "701" represents the total buffer memory size.

The amount of traffic per CDP at time T ₃ is as shown in the right block (702).

Under the buffer management attribute setting according to the preferred embodiment of the present invention, the CDP serves as a constant output buffer switch for each CDP. Thus, when traffic is input above its initial value, cell loss occurs in all types of cell delay priority buffers.

8A and 8B illustrate input cell queuing results of the occupancy and open buffer management attribute of type 1 (TYPE-1) according to an embodiment of the present invention.

Referring to FIG. 8A, "800" is a Type 1 (TYPE-1), which indicates a cell queuing state under each CDP type buffer management attribute set.

Referring to FIG. 8B, "801" represents the total buffer memory size.

The amount of traffic per CDP at time T ₃ is as shown in the right block (802).

Under the buffer management attribute setting according to the preferred embodiment of the present invention, it serves as a shared buffer switch that does not distinguish CDP. Therefore, even when traffic is input above its initial value, cell loss does not occur, but cell loss priority control service is not performed.

9A and 9B show input cell queuing results of four types of occupancy and open buffer management attributes according to an embodiment of the present invention.

Referring to FIG. 9A, "900" denotes each CDP type buffer management asset as Type 0 (TYPE-0), Type 1 (TYPE-1), Type 2 (TYPE-2), and Type 3 (TYPE-3), respectively. Represents the cell queuing state with the tree view set.

9B, " 901 " represents the total buffer memory size.

The amount of traffic per CDP at time T ₃ is as shown in the right block (902).

Under the buffer management attribute setting according to the preferred embodiment of the present invention, four cell delay priority control is completely executed according to the setting value of the buffer management attribute.

The present invention described above is capable of various substitutions, modifications, and changes without departing from the spirit of the present invention for those skilled in the art to which the present invention pertains, and the above-described embodiments and accompanying It is not limited to the drawing.

According to the present invention as described above, the dynamic queuing bandwidth allocation for the buffer memory for each cell delay priority in the ATM switch, it is possible to maximize the buffer memory utilization in accordance with the importance of the cell centered on the cell propagation delay time In addition, the service quality (QoS) of the ATM system is improved, and the buffer memory operation method is diversified to be able to quickly adapt to changes in application services.

Claims (4)

In the cell delay priority queuing bandwidth dynamic allocation method applied to the asynchronous transfer mode switch, A first step of configuring a buffer management attribute for each cell delay priority type that can be initialized during system operation; A second step of adjusting a buffer memory area that can be occupied by each cell type during system operation according to a characteristic of the configured attribute upon receiving the cell delay priority control request signal; And A third step of controlling traffic according to a service threshold for each type of cell delay priority for the buffer size; Cell delay priority queuing bandwidth dynamic allocation method comprising a. The method of claim 1, The first step is, A fourth step of determining whether a system reset has occurred during system startup; A fifth step of requesting an initial value for the buffer size for each cell delay priority type when a reset occurs, and ending the reset if no reset occurs; A sixth step of analyzing if an initial value is reported from the processor in a standby state and configuring an initial value acceptable in the buffer memory; A seventh step of initializing the buffer management register with the reported initial value if the allowed initial value is the result of the analysis of the sixth step and initializing its attribute register with the reported buffer management attribute; And An eighth step of initializing each register with an initial value and a buffer management attribute of its own default value if it is not an allowed initial value Cell delay priority queuing bandwidth dynamic allocation method comprising a. The method according to claim 1 or 2, The second step, A ninth step of analyzing a cell delay priority type from an input cell header; A tenth step of performing a queuing service within a buffer size limit given as an initial value if the priority type is a zero type in which the occupancy and open attribute values are set; As a result of the analysis of the ninth step, if the occupancy attribute is not set but the priority type in which the open attribute for the buffer is set is the first type, how much of the buffer area is occupied by another type group already? Determining an eleventh step; According to the determination result of the eleventh step, after analyzing the state of use of the buffer of the second type in which the occupancy attribute is set but the open attribute is set so as not to open its own buffer, the third type of the occupancy and the open attribute are both set. A twelfth step of calculating the size of the buffer finally allocated to the first type by analyzing the use state of the buffer in association; A thirteenth step of determining a buffer size of the third type by analyzing a use state of the third type of buffer if the priority type is the second type; And As a result of the analysis of the ninth step, if the priority type is the third type, the fourteenth step of determining a buffer size by analyzing a use state of the buffer of the second type Cell delay priority queuing bandwidth dynamic allocation method comprising a. The method of claim 3, wherein The third step, Determining whether the size of the cell storage buffer for each cell delay priority type from the input cell header is less than an upper limit threshold for the type; A sixteenth step of judging whether the size of the cell storage buffer for each cell delay priority type is smaller than a lower limit threshold for the type as a result of the determination in the fifteenth step; A seventeenth step of storing an input cell in a corresponding cell delay priority group cell buffer when the size of the cell storage buffer for each cell delay priority type is smaller than a lower limit threshold as a result of the determination in the sixteenth step; As a result of the determination in the 16th step, if the size of the cell storage buffer for each cell delay priority type is between an upper limit and a lower limit threshold, the processor may report a lower limit threshold exceeded state to the processor to fail and store the cell buffer in the type of cell buffer. An eighteenth step of storing an input cell in a corresponding cell delay priority group cell buffer; And As a result of the determination of the fifteenth step, if the size of the cell storage buffer for each cell delay priority type is greater than or equal to the upper limit threshold for the type, an upper limit threshold exceeded condition is reported to the processor for failure processing, and the corresponding cell delay priority is determined. 19th step to reject storage of input cell in group cell buffer Cell delay priority queuing bandwidth dynamic allocation method comprising a.

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