KR19980017791A - Data traffic processing device in deadline based real time traffic queue service device in ATM network - Google Patents

Abstract

The present invention provides a deadline-based real-time traffic queue service apparatus in an ATM network in which real-time traffic and data traffic can be efficiently accommodated using an amplifier flag signal in a deadline-based queue service scheme, thereby increasing bandwidth usage. A data traffic processing method according to the present invention, comprising: 0 th to n th FIFOs (9 to n) for inputting data from a plurality of virtual channels (VC0 to VCn) and outputting an amplifier flag signal (EF); Outputting the deadlines RT0 to RTn based on the amplifier flag signals EF0 to EFn from the 0th to nth FIFOs 9 to n and the virtual channel signal VC_sel from the comparator 40. 0 to nth deadline generating means 29 to n; Comparison means (40) for comparing the dead time (RT0 to RTn) from the 0th to nth dead time generating means (29 to n) and sequentially outputting a minimum time; And a multiplexer 20 for selectively outputting the connection identifier ID from the 0th to nth FIFOs 9 to n by the virtual channel signal VC_sel from the comparing means 40. do.

Description

Data traffic processing device in deadline based real time traffic queue service device in ATM network

The present invention relates to a data traffic processing apparatus for a deadline-based real-time traffic queue service device in an ATM network, and particularly, to efficiently accommodate real-time traffic and data traffic by using an amplifier flag signal in a deadline-based queue service method. The present invention relates to a data traffic processing method in a deadline based real time traffic queue service apparatus in an ATM network.

Meanwhile, the international telecommunication union-telecommunication standardization sector (ITU-TS) adopts an asynchronous transfer mode (ATM) as a technology to effectively promote a broadband integrated information communication network, and the ATM network uses all information. Since the packet is a packet of limited sized information units called cells, and is transmitted by statistical multiplexing, it is possible to flexibly accommodate various different services and efficiently use bandwidth.

Thus, the ATM network allocates as much bandwidth as necessary for the call to which access is allowed, but unless the bandwidth of the peak bit rate is provided, the traffic of the connected call is already allocated due to the predictable nature. Can be temporarily exceeded.

As a result, the network may be congested. In particular, bursty traffic such as moving images or high-speed data may have a large impact on the congestion. Therefore, in order to eliminate the drawbacks of ATM networks, various preservative and reactive network control techniques are needed, one of which is priority control. Network usage efficiency while ensuring the quality of service of all classes fairly by changing the buffering and transmission priority of cells entering the network according to the network status and the quality of service (QoS) of each class at regular intervals. To increase the

Meanwhile, the method of storing and managing the arriving cell in the queue and the scheduling method of determining the transmission order of the stored cells are collectively referred to as a queue service method, which maintains the quality of service at a level required by the user. A traffic control method for efficiently using the resources of This is because the queue service method developed around the data communication network is not suitable for ATM networks.

First, there will be an unprecedented number of services in the ATM network, which will have significantly different traffic characteristics, both qualitatively and quantitatively, which will result in a very different queuing scheme than in the case of data networks with similar data traffic. It becomes an important factor to demand.

In addition, since the service of the ATM network requires a variety of quality of service, it must be handled in different ways depending on whether it is a cell loss sensitive service or a delay sensitive service. Since real-time services such as voice and video services are included, quality of service related to delay becomes important.

Therefore, in case of data service, the average delay time is a condition for delay, and in case of real-time service, if the condition for delay is too strict, it cannot be transmitted within the time limit. As such, conditions for varying quality of service and stringent delays become another factor in requiring a new queue service scheme.

Therefore, in the queue service method, each cell performs a service within a delay limit by determining a service order based on a delay requirement. The scheduling method is a first-in-first-out (FCFS) method and a static priority. Method and dynamic priority method. The first-in, first-out method is the easiest to implement, but only one delay limit can be provided regardless of the type of traffic, making it difficult to use in a network with various traffic characteristics, and the fixed-priority method separates traffic into several classes. After that, the service can be provided with a fixed priority to provide a delay limit for each class.

In this case, there is a problem that the efficiency is slightly lowered because the fixed priority is always used regardless of the network state. In addition, in the dynamic priority method, priority is given in units of cells and then services are provided from the highest priority. This method is most efficient, but all cells must be classified in order to select the highest priority cell. Problems will arise.

In addition, the conventionally proposed priority control scheme is mainly performed based on the first in first out (FIFO) common buffer, and when the buffer is used, only the control of the occupancy of the buffer is possible, so that rapid control is not possible when congestion occurs. In addition, the conventional virtual clock queue service scheme is very complicated to implement because it is based on deadlines, and the management is complicated because it manages cells for all queues.

On the other hand, the above-mentioned case is focused on real-time traffic, so that the quality of service is effectively provided to real-time traffic, but not only real-time traffic but also data traffic exist in the actual network. The problem arises that must be accommodated.

Accordingly, the present invention is to solve the above problems, in the ATM network is to use the ampli flag signal in the deadline-based queue service method to efficiently accommodate the real-time traffic and data traffic to increase the bandwidth usage In a deadline based real-time traffic queue service apparatus of the present invention relates to a data traffic processing method.

The present invention for achieving the above object, the 0 to n-th FIFO for inputting data from the plurality of virtual channels and outputs the amplifier flag signal; Zeroth to nth dead time generating means for outputting a dead time based on the amplifier flag signal from the zeroth to nth FIFO and the virtual channel signal from the comparator; Comparison means for sequentially outputting a minimum time by comparing the dead time from the zeroth to nth dead time generating means; And a multiplexer for selectively outputting the connection identifier from the 0th to nth FIFOs by the virtual channel signal from the comparing means.

According to the present invention configured as described above, real-time traffic and data traffic can be efficiently accommodated using the amplifier flag signal in the deadline-based queue service method, thereby increasing bandwidth usage. This is because the data traffic is effectively used for the extra bandwidth where no real-time traffic is used, thereby increasing the bandwidth usage efficiency.

1 is a block diagram showing a data traffic processing apparatus in a deadline based real time traffic queue service apparatus in an ATM network according to the present invention;

2 is a block diagram of the deadline generator shown in FIG.

FIG. 3 is a diagram illustrating a configuration of a dead time (RT) count bit of real time traffic and data traffic from the dead time generator shown in FIG. 2.

Explanation of symbols on the main parts of the drawings

9 to n: 0 to nth FIFO, 20: multiplexer,

22,23: first and second counter, 24: deadline output,

25: oragate, 26: multiplier,

27: adder,

29 to n: 0th to nth deadline generator, 40: comparator.

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

First, the delay of ATM cell can be divided into two components: delay of constant size and irregular delay. Among the former, delay caused by cell decomposition and assembly of AAL layer is the main cause. When the ATM network and the existing PSTN network are interworked, it causes echo problems, and the latter causes delays in the multiplexing or switching process in the ATM layer, and transmission of operation, administration and maintenance (OAM) cells in the physical layer. This is caused by delay.

In addition, traffic having various service qualities and traffic characteristics is multiplexed and transmitted in an ATM network, and traffic having a variable bit rate allocated to a bandwidth below a maximum bit rate may exceed the negotiated bandwidth, which causes congestion. Therefore, priority control is performed to guarantee quality of service of a class that is sensitive to time delay through cell loss distribution and cell transmission order control through selective cell storage, discarding, and transmission amount control.

In addition, priority control is used to control the priority according to the quality of service between different traffic classes, and the low priority indicated by the priority bits of the cell head within the same traffic such as MPEG video. And control the storage and transmission of high priority cells.

In addition, the queue service discipline refers to a method of storing and managing an arriving cell in a queue and a method of determining a transmission order of stored cells, which guarantees user service quality and improves network utilization efficiency. Traffic control method to maximize. The queue service method is necessary wherever there is a queue such as B-NT (BISND-Network Termination) at the network entrance or ATM switch across the network, and the traffic arriving at the B-NT is irregular compared to the traffic in the network. Therefore, the queue service method in B-NT has a very important effect on network efficiency and service quality.

In addition, the queue service method has been mainly developed based on the existing data communication network, and the transmission delay variation is not a concern, and an attempt has been made to reduce the average transmission delay by serving a short packet first. And, the first come first serve (FCFS) to serve the packets that arrive first, the RR (round robin) to provide a fair service by putting a separate buffer for each channel, the head of the head (HOL) service according to strict priority line) is a typical queue service method of the existing data network.

However, in order to efficiently accommodate services of various characteristics in a BISDN environment where services are integrated and speeded up, research on a completely different queue service method is required. Therefore, consideration of cell delay variation (CDV) is essential due to the integration of real-time services, and the quality of each service must be guaranteed for each service, and the quality of other services is maintained even when there is a connection generating excessive traffic. You should be able to.

1 is a block diagram illustrating a data traffic processing apparatus in a deadline-based real-time traffic queue service apparatus in an ATM network according to the present invention. First, data arriving from each virtual channel (VC) is independently received. The data traffic is stored in a queue, for example, the 0th FIFO 9, which is stored in a predetermined queue for each connection, so that real-time traffic is stored in the first to nth FIFOs 10 to n, and the FIFOs 9 to n The data stored in) is selectively output by the multiplexer 20. When one cell arrives, data is input to a corresponding queue, and the multiplexer 20 outputs a connection identifier (CID).

When the real-time traffic and the data traffic are inputted to the FIFOs 9-n from the virtual channel, the deadline generators 29-n have an empty flag signal EF (empty-) from the FIFOs 9-n. Based on the flag, EF0 to EFn, and the selected virtual channel signal VC_sel from the comparator 40, a deadline, i.e., a remaining time (RT) of the cells until the deadline, is output.

Thereafter, the comparator 40 compares the deadlines RT0 to RTn from the deadline generators 29 to n to output the virtual channel signal VC_sel to the multiplexer 20 and the deadline generators 29 to n. ), The multiplexer 20 outputs the connection identifier CID of the FIFOs 9 to n by the virtual channel signal VC_sel from the comparator 40.

FIG. 2 is a block diagram of the deadline generator shown in FIG. 1, wherein the deadline generator comprises first and second counters 22, 23, deadline output 24, logical sum gate 25, and multiplier ( 26), the adder 27, and the comparator 28 are comprised.

First, the first counter 22, for example a down counter, is preset by a high level signal of the amplifier flag EF, for example, a value of 1 when the cell arrives before arrival. , For example 11... Will be 1. Further, the second counter 23, for example the down and up counters, is reset by a high level signal of the amplifier flag EF, for example, a value of 1, e.g. Will be zero. At this time, the deadline output unit 24 is the maximum time, for example, 11. By setting 1, the deadline time is logically infinite (∞).

When the first counter 22 is decremented by 1 every hour, that is, every 1 cell service time, and becomes 0, the first counter 22 is preset by the flow set value Vtick, and the second counter 23 is head-of-brain. The cell in the head of line (HOL) increases by one after receiving the service and decreases by one when the first counter 22 goes to zero.

Here, the dead time of the cell in the head of the brain (HOL) and the next cell is generated by the difference of the flow set value (Vtick). Therefore, when the cue becomes an amp, the first counter 22 is preset and the second counter 23 is reset to prepare cells to be input later, at which time the deadline is preset to logically infinity. Thereby not being selected by the deadline comparator 40.

On the other hand, when the flow set value Vtick is set to a predetermined value, for example, 5, when the cell arrives for the first time, since the value of the previous amplifier flag EF is 1, the logic sum gate 25 is used as the medium. Input to the first counter 22 causes the first counter 22 to be preset to five. Then, the second counter 23 is reset (R), for example, 0, and the value of 0 is input to the multiplier 26 so that the output value of the multiplier 26 becomes zero. Accordingly, the deadline output unit 24 receives only the flow set value Vtick, for example, a value of 5, from the first counter 22 so that the deadline RT, that is, the value of 5, is output.

Next, the expression representing the deadline of the virtual channel VC is

[Equation 1]

VC _i = max (VC _i-1 + V _tick , AT _i + V _tick )

It becomes In Equation 1, i denotes the i-th cell, and AT _i denotes the arrival time of the i-th cell.

On the other hand, if the flow setting value (Vtick) is 5, and represents the virtual clock (virtual clock) for the arrival cell as follows:

Here, when the first cell is input at t = 3 seconds, the virtual time of the first cell is

VC1 = max (0 + 5, 3 + 5) = 8 seconds

And, if the second cell is input at t = 4 seconds, the virtual time of the second cell

VC2 = max (8 + 5, 4 + 5) = 13 seconds

In addition, when the third cell is input at t = 11 seconds, the virtual time of the third cell is

VC3 = max (13 + 5, 11 + 5) = 18 seconds

And, if the fourth cell is input at t = 19 seconds, the virtual time of the fourth cell

VC4 = max (18 + 5, 19 + 5) = 24 seconds

In addition, when the fifth cell is input at t = 20 seconds, the virtual time of the fifth cell is

VC5 = max (24 + 5, 20 + 5) = 29 seconds.

When the comparator 28 selects the virtual channel information sel_VC selected from the deadline comparator 40, for example, the predetermined address information and the address information of the predetermined virtual channel VC, the comparator 28 receives a high level signal, for example, a value of 1. Will print. At the same time, the service for the cell of the virtual channel VC of the corresponding address is performed. Thereafter, the second counter 23 is increased by one by the value of one from the comparator 28.

FIG. 3 is a diagram showing the configuration of real time traffic from the deadline generator shown in FIG. 2 and the deadline (RT) count bits of data traffic. First, the deadline output from the deadline generators 29 to n shown in FIG. The count bit, i.e., the time bit (RT) in which the cell remains until the deadline, is the amplifier flag signal (EF) from the FIFOs (9 to n) in which the upper one bit is shown in FIG. 1 counter 22, i.e., the count bit Ci from the down counter.

Here, the deadline count bit RTo from the zeroth deadline generator 29 has the upper 1 bit set to 0, and the remaining bits have a maximum time, for example, 11. And the dead time count bits RT1 to RTn from the first to nth deadline generators 30 to n are obtained from the FIFOs 9 to n in which the upper one bit is shown in FIG. It is the amplifier flag signal EF, and the remaining bits become count bits Ci from the first counter 22.

On the other hand, in the structure of the deadline-based queue service method, the deadline belonging to the real-time traffic is calculated, and then the cell closest to the deadline is selected to serve. Accordingly, various types of FIFOs are used to store data according to the characteristics of the traffic, and the deadlines of the cells in the head-of-brain (HOL) of each FIFO are calculated, and then the cells to be serviced are selected. Here, the method of calculating the deadline of each cell is different depending on the algorithm.

And, the dead time of the cell in the head of the brain (HOL) is calculated by the down counter, the value of the down counter becomes smaller as time passes, which means that the dead time is approaching. In this way, the values of all the counters are compared at every moment so that the cell to be serviced can be selected.

In addition, one counter is used to accommodate the data traffic, and the AFT flag signal (EF) of each FIFO is used as the most significant bit (MSB) of the counter. And, the counter of the data traffic is constantly 11... It is set to 1, which means that if there is a cell of real time traffic, the cell of real time traffic is selected and serviced. If there is no cell of real time traffic, all the FIFO amplifier flag signals storing real time traffic are set to 1; Thus, the data traffic counter has the smallest value, so that the data traffic cell is selected and serviced. Therefore, data traffic is effectively used for the bandwidth when real time traffic is not used, thereby increasing bandwidth utilization efficiency.

On the other hand, the reference numerals written in the components of the claims of the present application to facilitate the understanding of the present invention, and are not written in the intention to limit the technical scope of the present invention to the embodiments shown in the drawings.

As described above, according to the present invention, in the deadline-based queue service scheme, real-time traffic and data traffic can be efficiently accommodated using the amplifier flag signal, thereby increasing bandwidth usage. This is because the data traffic is effectively used for the extra bandwidth where no real-time traffic is used, thereby increasing the bandwidth usage efficiency. In addition, each deadline generator manages a cell for each queue, thereby facilitating management and simplifying configuration.

Claims (3)

0th through nth FIFOs 9 through n that input data from a plurality of virtual channels VC0 through VCn and output an amplifier flag signal EF; Outputting the deadlines RT0 to RTn based on the amplifier flag signals EF0 to EFn from the 0th to nth FIFOs 9 to n and the virtual channel signal VC_sel from the comparator 40. 0 to nth deadline generating means 29 to n; Comparison means (40) for comparing the dead time (RT0 to RTn) from the 0th to nth dead time generating means (29 to n) and sequentially outputting a minimum time; And a multiplexer 20 for selectively outputting the connection identifier ID from the 0th to nth FIFOs 9 to n by the virtual channel signal VC_sel from the comparing means 40. A data traffic processing apparatus in a deadline based real time traffic queue service apparatus in an ATM network. 2. The deadline RT0 from the zeroth deadline generating means 29 is set by the upper 1 bit as 0, and the remaining bits are 11. A data traffic processing apparatus in a deadline-based real-time traffic queue service apparatus in an ATM network, characterized in that set to 1. The dead time RT1 to RTn from the first to nth dead time generating means 30 to n has a higher priority flag signal from the FIFOs 10 to n. And the remaining bits are set to the count bits (Ci) from the first counter (22).