KR101360718B1 - Scheduling method for deficit round robin type - Google Patents

Abstract

The present invention relates to a scheduling method of a definit round robin type.

According to an embodiment of the present invention, a scheduling method of a missing round robin method may include: comparing a packet service amount of a corresponding queue with respect to a packet to be transmitted; Transmitting a first transmission packet exceeding the packet service amount and recording an excess transmission amount of the transmitted packet; Transmitting the second transmission packet that does not exceed the packet service amount, and subtracting the remaining packet service amount from the excess transmission amount.

DRR, Missing Counter, Scheduler

Description

Scheduling method for deficit round robin method

1 is a view showing a scheduling system of the missing round robin for the present invention.

2 is a flowchart illustrating a round robin scheduling method according to an exemplary embodiment of the present invention.

<Explanation of symbols for the main parts of the drawings>

10: cue 20: deficit counter

30: scheduler

The present invention relates to a scheduling method of a definit round robin type.

Deficit Round Robin (DRR) is a method in which the basic service quota is fixedly set so that all flows through a network device share network resources evenly. There is a problem of unfairness when the size is different. In addition, the deficiency round robin method sets the number of bits each queue can handle at one time (one round robin), and processes the next round when the packet size of a flow is larger than that.

However, the conventional missing round robin method is a technique that fixedly sets the basic service quota, so that it cannot efficiently support the service of an application having a large amount of data and a variable packet size.

In addition, when a packet of multimedia services such as an Internet broadcast or video on demand, which has a very large packet size, is queued, the scheduler continues to reset the deficit counter for processing in the next round. Dozens of rounds will be traversed. At this time, there is a problem in that the service quality of an application requiring real-time processing is deteriorated due to a delay due to an unnecessary loss counter reset and round traversal.

The present invention provides a scheduling method of missing round robin.

The present invention provides a scheduling method of a missing round robin method that transmits even a packet larger than the basic service quota and then subtracts the excess transmission later.

According to an embodiment of the present invention, a scheduling method of a missing round robin method may include: comparing a packet service amount of a corresponding queue with respect to a packet to be transmitted; Transmitting a first transmission packet exceeding the packet service amount and recording an excess transmission amount of the transmitted packet; Transmitting the second transmission packet that does not exceed the packet service amount, and subtracting the remaining packet service amount from the excess transmission amount.

Hereinafter, the present invention will be described with reference to the accompanying drawings.

1 is a view showing a scheduling apparatus of a missing round robin according to an embodiment of the present invention.

Referring to FIG. 1, the scheduling apparatus includes a plurality of queues 10, a missing counter 20, and a scheduler 30.

The queue 10 temporarily stores transmission packets of each node and outputs the stored packets in a first-in first-out manner.

The deficiency counter 20 is arranged for each queue 10 and indicates the maximum number of bytes that the queue can send when the scheduler 30 visits the queue, and is initially initialized to zero. The deficit counter 20 includes a quota proportional to the weight of each queue 10, that is, a basic service quota, which is a byte proportional to the weight assigned to each queue. Have That is, the deficit counter 20 may be used as the sum of the remaining remaining counter and the basic service allocation amount.

The scheduler 30 sequentially visits each queue of a round according to a round robin method, and transmits packets to an output link as much as the quota allocated to the activated queue. Unused quotas are then stored in the loss counter and used with the quota allocated for the next round.

In addition, the scheduler 30 initially assigns the allocation counter differently according to the weight of each queue to the deficit counter, sequentially visits each queue, and transmits the packet by the allocated allocation amount. Unused quotas are then stored in the loss counter and used with the quota allocated for the next round. If the cue is deactivated, the loss counter is set to zero.

The scheduler 30 uses weights, basic service quotas, deficiency counters, and excess transmission thresholds as basic parameters to dynamically allocate service quotas.

The weight is the ratio of the packet service to the output port bandwidth in the same concept as the weight in the weighted fair queue.

The basic service quota (Quantam) has a unit of bytes proportional to the weight assigned to each queue 10. When the scheduler 30 visits the queue in a round robin manner, the deficiency counter 20 is a counter of the deficiency counter. It will send a packet plus storage and basic service quota (Quantam). That is, the operation of Deficit counter = Deficit counter + Quantam is performed.

If the transmission packet size becomes larger than the amount of the deficiency counter 20, the transmission packet is transmitted to the output port using an excess transmission threshold, and then paid off by subtracting in the next round. If it is less than the amount, the difference is stored in the counter 20, so that it can be sent by the amount less sent in the next round.

In this case, the excess transmission threshold value allows the packet to be transmitted first, even if there are more packets than the service allocation amount of the basic defect counter 20, and then subtracts the amount of the redundant loss counter at the next scheduling.

A scheduling method using such a scheduling apparatus will be described with reference to FIG. 2 as follows.

Referring to FIG. 2, when there is a sending packet of a predetermined size (i: size) when visiting the activated queue (S11), the defect counter (Deficit Counter) of the defect counter (initial = 0) The amount of packet service of the corresponding queue is determined by adding the amount and the basic service quota (Quantam) (S13).

The transport packet size i is compared with the deficit counter (S15). As a result, if the transport packet size i is less than or equal to the deficiency counter, the corresponding packet is transmitted (S17).

The defect counter is then updated (S19). Here, the missing counter is updated by subtracting the transport packet size (Deficit Counter = Deficit Counter-i) from the missing counter determined in S13. For example, if the basic service quota (Quantam) is 50KB (byte), the initial deficit counter amount is 50KB, and if the transmission packet is 30KB, 20KB is left in the newly updated deficit counter. That means you can send as much as 20KB later.

Then, it is checked whether there is an overdraft (S21). If there is no excess transmission amount as a result of checking in S21, the process proceeds to the next round, and if there is excess transmission amount, the missing counter is newly updated (S23). In other words, the second update of the missing counter subtracts the overdraft from the first updated counter in S19. For example, if there is 20KB in the first missing counter and the excess transmission amount is 10KB, then S23 is updated to a 10KB missing counter.

Then, it is compared whether or not the missing counter is 0 or less (S25), and if it is less than or equal to 0, the missing counter is set to 0 (S27). For example, if the remaining loss counter is 10 KB, the loss counter becomes 60 KB plus 10 KB plus a basic service quota of 50 KB in S13.

As a result of the comparison in step S15, when the transport packet size (i) exceeds the amount of the missing counter, the transport packet size (i) is compared with the missing counter of S13 by adding an excess transmission threshold. (S29).

When the size of the transport packet is small as a result of the comparison in step S29, the transport packet is transmitted (S31), and the overdraft is calculated and recorded by subtracting the amount of the deficiency counter determined in S13 from the transport packet size (S33). ). Then set the missing counter to 0 to run the next round.

The excess transmission amount generated at this time may be compared by the step S21 in the next round, and may be subtracted using the amount of the missing counter remaining in each round by the step S27. For example, if the transmission packet size is 100 KB, the loss counter of S13 is 50 KB, and the excess transmission threshold is 100 KB, the excess transmission amount is 50 KB.

Here, the excess transmission threshold value may cover the maximum packets that can be overtransmitted, that is, the capacity temporarily stored in each queue, if the size of the packet to be transmitted is greater than the amount of the deficiency counter. Can be sized. In addition, the excess transmission amount is a variable for recording the excess amount when the packet is transmitted by comparison with the excess transmission threshold even if the size of the packet is larger than that of the missing counter.

In the present invention, when the scheduler visits each queue in a round robin manner, the scheduler assigns a default service quota (Quantam) differently assigned according to the amount of missing counters remaining and the weight of each queue, and gives the value back to the missing counter. The amount of the missing counter is compared with the size of the packet to be serviced, and the packets are transmitted until the amount of the missing counter is smaller than the size of the next packet to be served. In addition, the amount of surplus deficit counter after packet transmission is preserved and deducted for the next round.

If the size of the packet to be transmitted exceeds the predetermined amount of the missing counter, the size of the packet to be transmitted is transmitted as the sum of the missing counter and the excess transmission threshold. At this time, the number of bytes transmitted is recorded in the overdraft of the queue after packet transmission. Then, when sending a packet smaller than the missing counter amount, any excess bytes generated are subtracted by the number of excess transmitted bytes that occurred in the previous round, which is recorded in the excess amount.

In this way, a large-capacity packet such as multimedia can be transmitted in real time to reduce the delay of the entire queue, and a service quota can be borrowed in the current round and used to pay off the remaining service quota in a later round.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, It will be understood that various modifications and applications other than those described above are possible. For example, each component specifically shown in the embodiments of the present invention can be modified and implemented. It is to be understood that all changes and modifications that come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

According to the scheduling method of the missing round robin method according to an embodiment of the present invention, the delay time due to the unnecessary reset counter and the number of round iterations can be shortened, thereby improving the service quality of an application requiring real time processing. have.

In addition, in a communication environment in which the packet size difference between applications is very large, an optimal communication service can be provided by dynamically setting a service allocation amount according to the packet size.

Claims (6)

A scheduler comparing the size of a transmitted packet with a packet service amount of a corresponding queue recorded in a missing counter; If the size of the transport packet exceeds the packet service amount, the scheduler transmitting the transport packet and recording the excess amount of transmission as a result of subtracting the packet service amount from the size of the transport packet; And If the size of the transport packet is less than or equal to the packet service amount, the scheduler transmits the transport packet and updates the deficiency counter, The updating step, The missing round robin scheduling method of subtracting the size of the transmission packet from the packet service amount and subtracting the excess amount of transmission previously recorded, and recording the result in the missing counter. The method according to claim 1, And the packet service amount includes a basic service allocation amount allocated to the queue. 2. The method of claim 1, And if the size of the transport packet is less than the excess service threshold value added to the packet service amount, transmitting the transport packet and recording the excess amount of transmission. delete The method of claim 1, wherein the updating comprises: And if the result of subtracting the previously recorded excess transmission amount is equal to or less than zero, the missing round robin scheduling method records the missing counter as zero. 2. The method of claim 1, The missing round robin scheduling method of recording the missing counter to zero.

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