KR0185863B1 - Apparatus of processing the data traffic in real time traffic queuing service on the basis of deadline of cell in atm networks - Google Patents

Abstract

The present invention relates to 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 flag in a deadline-based queue service scheme, A 0th to an nth FIFOs 9 to n for inputting data from a plurality of virtual channels (VC0 to VCn) and outputting an amplifier flag signal (EF); (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 N to n < th > dead time generating means (29 to n); Comparison means (40) for comparing the finishing time (RT0 to RTn) from the 0th to nth finishing time generating means (29 to n) and sequentially outputting the minimum time; And a multiplexer 20 for selectively outputting a connection new identifier (CID) from the 0th to the n-th FIFOs 9 to n by a virtual channel signal VC_sel from the comparison means 40 do.

Description

A data traffic processing apparatus in a deadline-based real-time traffic queue service apparatus in an ATM network

The present invention relates to an apparatus for processing data traffic in a deadline-based real-time traffic queue service apparatus in an ATM network. More particularly, the present invention relates to an apparatus and method for efficiently processing real- To a deadline-based real-time traffic queue service apparatus in an ATM network.

In the meantime, in the international telecommunication union-telecommunication standardization sector (ITU-TS), asynchronous transfer mode (ATM) is adopted as an underlying technology in order to effectively promote a broadband integrated information network, The packet is formed into a packet having a limited size of information unit called a cell and is statistically multiplexed and transmitted so that the bandwidth can be efficiently used while flexibly accommodating services of different characteristics.

Thus, the ATM network allocates as much bandwidth as needed for the call that is allowed to connect, but unless the bandwidth of the peak bit rate is provided, the traffic of the connected call will have a bandwidth Can be temporarily exceeded.

This can cause the network to fall into congestion. Especially, traffic with high bursts, such as moving images and high-speed data, has a great impact on congestion. Therefore, various preventive and reactive level network control techniques are required to eliminate the disadvantages of the ATM network. One of them is priority control, By buffering the cells entering the network and changing the transmission priority according to the network status and the quality of service (QoS) of each class, the quality of service of all classes is fairly guaranteed, .

Meanwhile, a queue service method is collectively referred to as a method of storing and managing the arriving cells in a queue and a scheduling method of determining a transmission order of stored cells. This is called a queue service method, Is a traffic control method for efficiently using resources of a base station. This means that the queue service method developed around the data communication network is not suitable for the ATM network.

First of all, there will be an unpredictable number of services in the ATM network, which will have significantly different traffic characteristics, both qualitatively and quantitatively. This means that the queue service method, which is significantly different from that of the data communication network with similar characteristics of data traffic It becomes an important factor to demand.

Since the ATM network service requires various service qualities, it must be handled differently depending on whether the service is sensitive to cell loss or delay-sensitive services. In the existing data communication network, the loss rate is a main service quality parameter. Real-time services such as voice and image services are included in the service quality related to the delay.

Therefore, in case of data service, the average delay time is a condition related to delay. In case of real-time service, if the condition for delay is very strict, if it can not be transmitted within the time limit, the same effect as lost is obtained. As such, the conditions for varying quality of service and strict delays become another factor requiring a new queue service approach.

In the queue service scheme, a service order is determined according to a delay requirement, so that each cell performs a service within a delay limit. The scheduling method includes a FCFS scheme and a static priority scheme, Method and a dynamic priority method. Since the first-in first-out method is easiest to implement, but it can tolerate only one delay limit regardless of the type of traffic, the characteristics of the traffic are difficult to use in various networks. In the fixed priority method, It is possible to provide a delay limit for each class by performing the service with a fixed priority.

In such a case, since the fixed priority is always used irrespective of the state of the network, there is a problem that the efficiency is slightly lowered. In the dynamic priority scheme, priority is given to each cell, and then service is provided from the highest priority. This method is most efficient, but all the cells must be classified to select the highest priority cell A problem occurs.

The conventional priority control scheme, which is conventionally proposed, is based on a FIFO (first in first out) common buffer. When this buffer is used, only buffer occupancy control is possible. In addition, since the conventional virtual clock queue service method is based on the deadline, the implementation is very complicated and management is complicated because it manages cells for all queues.

Meanwhile, in the above case, the focus is on the real-time traffic, so that the service quality is effectively provided to the real-time traffic. However, in the actual network, not only the real-time traffic but also the data traffic exists. There is a problem to be accommodated.

SUMMARY OF THE INVENTION Accordingly, the present invention has been made to solve the above-mentioned problems, and it is an object of the present invention to provide an ATM network in which real time traffic and data traffic can be efficiently accommodated using an amplifier flag signal in a deadline- To a method for processing data traffic in a deadline-based real-time traffic queue service apparatus.

According to an aspect of the present invention, there is provided a data processing apparatus including: a 0th to an nth FIFO for receiving data from a plurality of virtual channels and outputting an amplifier te flags signal; Th 0th to nth deadline generating means for outputting a dead time based on the amplifier tee flag signal from the 0th to nth FIFOs and the virtual channel signal from the comparator; Comparison means for sequentially outputting the minimum time by comparing the deadlines from the 0th to nth deadline generating means; And a multiplexer for selectively outputting a connection differentiator from the 0th to the nth FIFOs by a virtual channel signal from the comparison means.

According to the present invention configured as described above, real-time traffic and data traffic can be efficiently accommodated using an amplifier tee flag signal in a deadline-based queue service scheme, thereby increasing bandwidth usage. This effectively increases the efficiency of bandwidth usage because data traffic is effectively used for extra bandwidth where real-time traffic is not used.

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

Figure 2 is a block diagram of the deadline generator shown in Figure 1;

FIG. 3 is a diagram showing the construction of the deadline (RT) count bits of the real-time traffic and data traffic from the deadline generator shown in FIG. 2;

DESCRIPTION OF THE REFERENCE NUMERALS

N th to n th FIFO 20: multiplexer

22, 23: first and second counters 24: deadline output section

25: O gate 26:

27: adder

N-th to n-th finishing time generator 40: comparator

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

First, the delay of the ATM cell can be separated into two components of a constant size delay and an irregular delay. In the former case, the delay occurring in the cell decomposition and assembly process of the AAL layer is a main cause, The latter causes echo problems when interworking with the ATM network and the existing PSTN network. The latter causes latency caused by the multiplexing or switching process at the ATM layer, transmission of the operation, administration and maintenance (OAM) And the delay caused by the above.

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

In addition, the priority control is performed in the case of controlling the priority according to the quality of service between different traffic classes and the case in which the priority bit of the cell head (head) And the case of controlling the storage and transmission of high priority cells.

The queue service discipline means a method of storing and managing the arriving cells in the queue and a method of determining the transmission order of the stored cells, It is a traffic control method to maximize. The queue service method is required everywhere where there is a queue, such as a BISN (B-NT) network termination at the network entrance or an ATM switch over the entire network. In particular, traffic arriving at the B- Therefore, the queue service 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 existing data communication networks, and transmission delay variation is not a concern, and there has been an attempt to reduce the average transmission delay by first servicing packets having a short length. The first come first serve (FCFS), which provides the first packet to arrive first, the round robin (RR), which provides a fair buffer for each channel, and the head of line (HOL) line) is a typical queue service method of existing data networks.

However, in order to effectively accommodate various types of services in a BISDN environment that speeds up the integration of services, research on a completely different queue service method becomes necessary. Therefore, it is necessary to consider the cell delay variation (CDV) due to the integration of real-time service, guarantee different quality for each service, and maintain the quality of other services even when there is a connection generating excessive traffic .

FIG. 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) Real-time traffic is stored in the first to n-th FIFOs 10 to n, in addition to storing data traffic in a queue stored in a predetermined queue for each connection, for example, the 0th FIFO 9, Are selectively output by the multiplexer 20. [0050] Here, when one cell arrives, the data is input to the corresponding queue, and the multiplexer 20 outputs a connection identifier (CID).

When the real-time traffic and the data traffic are input from the virtual channel to the FIFOs 9 to n, the deadline generator 29 to n outputs an amplifier-flag signal EF from the FIFO 9- flag, EF0 to EFn) and the selected virtual channel signal (VC_sel) from the comparator 40. The dead time, that is, the remaining time (RT), of the cell remains until the deadline.

Thereafter, the comparator 40 compares the deadlines RT0 to RTn from the deadline generator 29 to n and outputs the virtual channel signal VC_sel to the multiplexer 20 and the deadline generator 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 includes first and second counters 22 and 23, a deadline output 24, an OR gate 25, 26, an adder 27, and a comparator 28. As shown in FIG.

The first counter 22, for example, a down counter may be preset (PR) by a high level signal, for example, a value of 1, of the amplifier T flag EF before the cell arrives, , Such as 11 ... 1. The second counter 23, for example, a down / up counter, is reset by a high level signal of the amplifier T flag EF, for example, a value of 1, for example, 00 ... 0 < / RTI > At this time, the deadline output unit 24 outputs the maximum time, for example, 11 ... 1 and the dead time RT becomes logically infinite (∞).

The first counter 22 is preset by the flow set value Vtick when it is decremented by one every hour, that is, every one cell service time, and becomes 0, and the second counter 23 is preset by the head- A cell in the head of line (HOL) is incremented by 1 after receiving a service and decremented by 1 when the first counter 22 becomes 0.

Here, the dead time of the cell in the head of line (HOL) and the next cell is different by the flow set value (Vtick). Accordingly, when the queue becomes an amplifier, the first counter 22 is preset and the second counter 23 is reset to prepare a cell to be input later, at which time the deadline is pre-set and logically infinite So that it is not selected by the deadline time 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, 1 counter 22 so that the first counter 22 is preset to 5. Then, the second counter 23 is reset (reset), for example, becomes 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 outputting unit 24 receives only the flow set value Vtick, for example, 5 from the first counter 22, and outputs the deadline RT, that is, a value of 5.

Next, the expression indicating the deadline time of the virtual channel (VC)

[Equation 1]

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

. In Equation (1), i represents an i-th cell and AT _i represents an arrival time of an i-th cell.

On the other hand, if the flow set value Vtick is 5, if the virtual clock for the arriving cell is expressed as follows,

Here, if 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

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

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

Further, 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

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

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

Further, 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.

The comparator 28 compares the value of the high level signal, for example, 1, with the value of the virtual channel information sel_VC selected from the deadline comparator 40, for example, when the predetermined address information matches the address information of the predetermined virtual channel VC . At the same time, the service for the cell of the virtual channel (VC) at the corresponding address is performed. Thereafter, the value of 1 from the comparator 28 causes the second counter 23 to increment by one.

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

Here, the deadline count bit RTo from the 0th deadline generator 29 is set such that the upper one bit is set to 0 and the remaining bits are set to the maximum time, e.g., 11 ... 1 from the first to n-th finishing time generators 30 to n, the dead time count bits RT1 to RTn from the first to n < th > And the remaining bits become the count bit Ci from the first counter 22. [0050]

On the other hand, in the deadline-based queue service scheme, a deadline belonging to real-time traffic is calculated, and a cell close to the deadline is selected and served. Accordingly, various kinds of FIFOs are used according to the characteristics of the traffic, data is stored, deadlines of cells in the head of line (HOL) of each FIFO are calculated, and then the cells to be serviced are selected. Here, the method of calculating the deadline time of each cell differs depending on the algorithm,

The dead time of the cell in the head of line HOL is calculated by the down counter, and the value of the down counter becomes smaller as time elapses, which means that the dead time is approaching. In this manner, 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 amplifier flag signal EF of each FIFO is used as the MSB (most significant bit) of the counter. And the data traffic counter is constantly 11 ... 1, the cell of the real-time traffic is selected and served when the cell of the real-time traffic exists, and when the real-time traffic does not exist, the amplifier flag signal of all the FIFOs storing the real- And the counter of the data traffic has the smallest value, so that the cell of the data traffic is selected and served. Therefore, the data traffic is effectively used for the bandwidth in the case where real-time traffic is not used, and the utilization efficiency of the bandwidth is increased.

It should be noted that the drawings are not intended to limit the technical scope of the present invention to the embodiments shown in the drawings in order to facilitate understanding of the present invention.

As described above, according to the present invention, real-time traffic and data traffic can be efficiently received by using the amplifier tee flag signal in the deadline-based queue service method, and the bandwidth usage is increased. This effectively increases the efficiency of bandwidth usage because data traffic is effectively used for extra bandwidth where real-time traffic is not used. In addition, each deadline generator controls the cells for each queue, which facilitates management and simplifies the configuration.

Claims (3)

Nth to n-th FIFOs (9 to n) for receiving data from a plurality of virtual channels (VC0 to VCn) and outputting an amplifier teflag signal (EF); (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 N to n < th > dead time generating means (29 to n); Comparison means (40) for comparing the finishing time (RT0 to RTn) from the 0th to nth finishing time generating means (29 to n) and sequentially outputting the minimum time; And a multiplexer 20 for selectively outputting a connection new identifier (CID) from the 0th to the n-th FIFOs 9 to n by a virtual channel signal VC_sel from the comparison means 40 A device for processing data traffic in a deadline - based real - time traffic queue service device in an ATM network. 2. The method according to claim 1, wherein the deadline time (RT0) from the 0th deadline time generating means (29) is set so that the upper one bit is set to 0 and the remaining bits are set to 11 ... 1 is a time-based traffic queue service apparatus based on deadlines in an ATM network. The semiconductor memory device according to claim 1, wherein the dead time (RT1 to RTn) from the first to nth dead time generating means (30 to n) ) And the remaining bits are set to a count bit (Ci) from the first counter (22).