JP2001086127A - Optimum transfer system and method by traffic characteristic - Google Patents

Abstract

PROBLEM TO BE SOLVED: To minimize a delay of real time data and to minimize discarded non real time data by discriminating received traffic into the real time data and the non real time data. SOLUTION: The optimum transfer system by traffic characteristic to optimally transfers real time data and non real time intermingled with each other is provided with a traffic discrimination section 2 that discriminates the received traffic to be real time data and non real time data, a traffic distribution section 3 that distributes the received traffic into the real time data and the non real time data, an NRT memory 4 that stores the distributed non real time data, a transmission selection signal generating section 6 that generates a transmission selection signal for the real time data and the non real time data on the basis of discrimination information of a traffic discrimination section and storage quantity information of the NRT memory, and a transmission traffic selection section 5 that selects and transmits the real time data from the traffic distribution section or the non real time data from the NET memory according to the transmission selection signal of the transmission selection signal generating section.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an ATM (Asynchr).
The present invention relates to an integrated communication network such as an on-transfer mode (asynchronous transfer mode). In particular, the present invention relates to an optimized transfer system and method according to traffic characteristics in an integrated communication network.

[0002]

2. Description of the Related Art A communication network such as the ATM described above includes:
Real-time data and non-real-time data
There are species. For non-real-time data, delays are allowed, but basically the loss of data must be zero.

On the other hand, for real-time data,
We want to avoid delays as much as possible, but some data loss is acceptable. Conventionally, for this conflicting traffic,
A method for managing real-time data and non-real-time data at the connection level has been devised by preparing a buffer for each connection called VC Quing and using a buffering method that reflects characteristics specific to the connection. I have.

There is also a method of reflecting characteristics on a connection-by-connection basis also by various priority-based buffer call control.

[0005]

However, when the above method is used, it is considered effective for a certain unit, for example, a connection. However, the unit further includes real-time data / non-data. When real-time data is mixed, there is a problem that effective measures may not be taken.

Therefore, in view of the above problems, the present invention discriminates received traffic into real-time data and non-real-time data, and sets traffic characteristics to minimize delay of real-time data and discard minimum of non-real-time data. Another object of the present invention is to provide another optimized transfer system and method.

[0007]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a traffic characteristic-based optimized transfer system for optimally transferring mixed real-time data and non-real-time data. A traffic discriminator for discriminating between real-time data and non-real-time data,
A traffic distribution unit that distributes the received traffic to real-time data and non-real-time data based on the discrimination information of the traffic determination unit, and an NR that stores the non-real-time data distributed by the traffic distribution unit
A T memory, a transmission selection signal generation unit that generates a transmission selection signal of real-time data or non-real-time data based on the discrimination information of the traffic discrimination unit and the storage amount information of the NRT memory; Real-time data or NR from the traffic distribution unit according to the transmission selection signal of the unit.
And a transmission traffic selection unit for selecting and transmitting non-real-time data from the T memory (4).

By this means, the received traffic is discriminated into real-time data and non-real-time data, the delay of the real-time data is minimized, and the non-real-time data is discarded.
Preferably, the transmission selection signal generation unit gives priority to transmission of real-time data in principle, and transmits non-real-time data when a large amount of non-real-time data is stored according to the storage amount information of the NRT memory. The transmission of the non-real-time data is inserted between the distribution and the transmission of the distributed real-time data.

By this means, transmission of real-time data is given priority in principle, but non-real-time data is not unilaterally treated as low priority. By allowing time data to be discarded or delayed, transfer of non-real-time data can be realized at the same time.
Preferably, the transmission selection signal generator determines that a large amount of non-real-time data is accumulated when the ratio of the used memory amount to all the memories of the NRT memory exceeds a certain threshold, Is provided with hysteresis.

By this means, a large amount of non-real time data is quantitatively determined. Preferably, the transmission selection signal generation unit permits the transmission traffic selection unit to transmit non-real time data when there is no reception of real time data. By this means, even if a large amount of non-real-time data is not stored, transmission of non-real-time data is performed if no real-time data exists.

Preferably, the traffic discriminating unit comprises:
The real-time data and the non-real-time data are determined by identifying the AAL type. By this means, for example, A
If it is AL1 / 2, it is recognized as real-time data, and if it is AAL3 / 4/5, it is recognized as non-real-time data. Preferably, the NRT memory comprises a FIFO.

By this means, the output is performed from the memory in accordance with the arrival order of the information. Preferably, the NRT
The memory assigns priorities to the non-real-time data and accumulates the classified data, and the transmission selection signal generator controls the reading of the non-real-time data from the NRT memory based on the priority. By this means, uniform delay of non-real time data can be prevented, and efficient network use can be required.

Preferably, further, an output buffer is connected to the transmission traffic selection unit, the output buffer reads information as a set from the NRT memory, and the transmission selection signal generation unit writes data from the output buffer. The prohibition signal is monitored, and if the writing is prohibited, the transmission of the non-real time data is terminated. By this means, non-real time data can be read out from the NRT memory not as a cell (or a fragmented packet) but as a set of information such as a packet unit. In this case, there is a possibility that a delay up to the buffer accumulation amount may occur for real-time data, but in terms of information transfer amount,
Since retransmission associated with discarding non-real-time data can be prevented, network use efficiency can be reduced.

Preferably, a timer is provided in the NRT memory, the timer monitors a writing time of the non-real-time data to the NRT memory, and the transmission selection signal generating unit specifies the writing time. If the threshold is exceeded,
It is determined that a large amount of non-real time data is accumulated, and the threshold value is provided with hysteresis. By this means,
In a protocol that needs to receive an acknowledgment within a certain period of time, it is possible to suppress a delay amount using a timer, and to reduce network use efficiency due to occurrence of retransmission.

Further, the present invention provides a traffic characteristic-based optimized transfer method for optimally transferring mixed real-time data and non-real-time data, and discriminates received traffic into real-time data and non-real-time data. Process and
A step of distributing the received traffic to real-time data and non-real-time data based on the determined information; a step of storing the distributed non-real-time data; Generating a transmission selection signal for real-time data or non-real-time data based on the accumulation amount information; and selecting distributed real-time data or accumulated non-real-time data based on the generated transmission selection signal. And transmitting the data. The optimized transmission system for each traffic characteristic is provided.

By this means, similarly to the above invention, the received traffic is discriminated into real-time data and non-real-time data, real-time data is minimized in delay, and non-real-time data is discarded in minimum.

[0017]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram illustrating a schematic configuration of the traffic-specific optimized transfer system according to the present invention. As shown in the figure, the traffic characteristic-based optimized transfer system is provided with a traffic discriminating unit 2, which inputs an input signal 1 including a plurality of types of connections, From information that needs to be transferred in real time and data that does not cause a problem in non-real time transfer.

That is, the traffic discriminating section 2 1) registers whether the data corresponds to real-time data or non-real-time data for each connection and classifies the data. 2) AAL (ATM Adaptation Layer)
r) to identify the AAL type, for example,
AAL1 / 2, real-time data, AAL3 / 4/5
If so, it recognizes that it is non-real-time data, makes a determination,

3) Terminate Layer 3 which is higher than the AAL. 3-a) Identify the transfer address of the terminated information. 3-B) TCP / IP (Transmission C)
ontrol Protocol / Internet
In the case of (Protocol), real-time data and non-real-time data are discriminated based on the information of the received data and the registered information by identifying port information or the like, and traffic is determined as to which received data is applicable. The characteristics are individually identified, and a traffic determination signal 21 is output.

By defining the termination layer and the identification method in accordance with the type of information transferred in the traffic discriminating unit 2, the present invention can correspond to various types of transfer information such as cell, packet and frame. Become. A traffic distribution unit 3 is connected to the traffic discrimination unit 2,
The traffic discrimination unit 2 transmits a traffic discrimination signal 21 as a result of the discrimination to the traffic distribution unit 3.

The traffic distribution unit 3 receives the input signal 1 and the traffic discrimination signal 21 of the traffic discrimination unit 2, and distributes the input signal 1 into real-time data and non-real-time data according to the instruction of the traffic discrimination signal 21. The traffic distribution unit 3 is connected to a non-real-time data storage memory (hereinafter, referred to as NRT memory) 4 and a transmission traffic selection unit 5.

The traffic distribution unit 3 sends the output destination to the transmission traffic selection unit 5 via the output 31 in the case of real time data and to the non-real time data storage memory 4 via the output 32 in the case of non-real time data. Select and send. The traffic discriminating unit 2 is further connected to a transmission selection signal generating unit 6.
Is transmitted to the transmission selection signal generator 6 as a result of the determination.

The NRT memory 4 stores information transmitted as non-real time data in the memory. Also, NRT
The memory 4 is a FIFO (First In First)
Out) structure, and has a storage element 41 and an address management unit 42.

The address management unit 42 of the NRT memory 4
The address information written in the storage element 41 is managed by the output 32 of the traffic distribution unit 3. Address management unit 4
Numeral 2 controls the storage state of the memory by managing the write address and the call address, which is a well-known management method. In the NRT memory 4, output is performed from the memory according to the order of arrival of information.

The address management unit 42 transmits the storage amount information 43 to the transmission selection signal generation unit 6. Here, the accumulation amount information 43 indicates to what extent the NRT memory 4 is used for holding non-real time data. FIG. 2 is a diagram illustrating the storage amount information 43 formed by the address management unit 42.
As shown in FIG. 3A, the ratio of the used memory amount to the total memory amount of the NRT memory 4, for example, the threshold value 80%
In this case, the storage amount information 43 is generated and output as “1” as shown in FIG. 9B, and the total memory amount versus the used memory amount drops to the threshold of 60% due to the decrease in the storage amount. Sometimes, the generation / output of the accumulation amount information 43 is canceled,
A signal having hysteresis is generated such that the signal becomes "0". In this way, the accumulation amount information 43 is obtained quantitatively.

The NRT memory 4 simply transmits only the memory usage to the transmission selection signal generator 6 and
It is also possible to calculate the storage amount information 43 from the memory amount. The transmission selection signal generation unit 6 receives the traffic discrimination signal 21 from the traffic discrimination unit 2 and the storage amount information 43 from the address management unit 42, and transmits, for example, according to a determination method shown in the following selection flow. The information to be determined is determined and the transfer is optimized.

The transmission selection signal generator 6 basically gives priority to real-time data for transmission selection. However, in general, real-time data can be partially supplemented by a redundant code for partial loss. Considering that it is not necessary to retroactively supplement information in the real-time data such as images even if an instantaneous loss occurs, priority should be given in the event that a large amount of non-real-time data is accumulated. The order is exchanged to create a state in which non-real-time data can be transmitted.

FIG. 3 shows the transmission selection signal generator 6 in FIG.
5 is a flowchart for explaining the operation of FIG. Step S1
, The transmission selection signal generator 6 inputs the traffic discrimination signal 21 of the traffic discriminator 2 for discriminating whether or not real-time data has arrived. In step S2, if there is real-time data, the transmission selection signal
With reference to the storage amount information 43 from the address management unit 42 in the RT memory 4, it is determined whether the storage amount exceeds a set threshold of the ratio of the used memory amount to the total memory amount of the NRT memory 4. .

In step S3, if the threshold is not exceeded, the transmission selection signal generator 6 outputs a transmission selection signal 61 for selecting transmission of real time data to the transmission traffic selector 5, and ends the processing. In step S4, if there is no real-time data in step S1,
The transmission selection signal generator 6 sets the transmission selection of the non-real time data to a low priority.

In step S5, the transmission selection signal generator 6 outputs the non-real-time data transmission selection signal 61, and the process ends. In step S6, if the storage amount information 43 exists in step S2 and the threshold value is exceeded, the priority of non-real-time data transmission selection is referred to. If the priority is high, the process proceeds to step S4, where the priority is set low, and step S4 is performed.
In step 5, a non-real time data transmission selection signal 61 is output. This output minimizes discarding of non-real time data.

If the priority is low in step S7, the priority is set to high, the output of the non-real-time data is postponed until the next transmission opportunity, and the process proceeds to step S3. This delay minimizes real-time data delay. As a result of the above-described processing performed by the transmission selection signal generator 6, the transmission selection signal 6
1 is transmitted to the transmission traffic selector 5. The transmission traffic selection unit 5 selects one of the input 31 and the input 44 according to the transmission selection signal 61 and outputs it to the output 51.

As described above, even if a large amount of non-real-time data is accumulated, the priority is determined to be a certain percentage in the above-described flowchart when real-time data arrives continuously without interruption. , The transmission of the real-time data is distributed so that the transmission of the non-real-time data is inserted between the transmissions of the distributed real-time data. In this way, a state in which non-real-time data can be transmitted is created by appropriately changing the priority order.

In the present flowchart, the setting of the priority is set to 1/2 each, but it is of course possible to set the priority based on a certain ratio. When no real-time data exists, non-real-time data can be transmitted without any condition. Therefore, according to the present invention, in a communication environment in which real-time data and non-real-time data coexist, it is possible to determine the coexistence by traffic characteristics and to effectively transfer the real-time data effectively.

As specific effects, 1) reduction of transfer delay in real-time data by transferring real-time data with the highest priority; and 2) non-real-time data is allowed because transfer delay for non-real-time data is allowed. By being able to centrally allocate memory as dedicated, it is possible to reduce the amount of buffer uniformly given to all connections seen in Per VC Quing,

3) Non-real-time data is sequentially written in the order of arrival, and is simply read in the order of writing.
It becomes possible to simplify the read control mechanism such as WRR. FIG. 4 is a diagram showing a modification of FIG. As shown in the figure, as compared with FIG.
An RT memory 7 is additionally provided. The NRT memory 7 has a storage element 71 and an address management unit 72.

The purpose of the NRT memory 7 is to prevent non-real-time data from being uniformly delayed by prioritizing the non-real-time data in the traffic. The storage amount information of the plurality of non-real-time memories is input to the transmission selection signal generation unit 6, and the transmission selection signal generation unit 6 further assigns different priorities among these memories, so that the transmission selection signal generation unit 6 receives the information from the plurality of memories. The number of readings can be controlled.

As a result, it is possible to use the network efficiently by classifying the non-real time data. FIG. 5 is a diagram showing another modification of FIG. As shown in this figure, compared to FIG.
, An output buffer 8 is additionally provided on the output side.

By using the output buffer 8, the non-real-time data can be read from the memory not as a cell (or a fragmented packet) but as a set of information such as a packet. In this case, there is a possibility that a delay up to the buffer accumulation amount may occur for real-time data, but in terms of information transfer amount,
Since retransmission associated with discarding non-real-time data can be prevented, network use efficiency can be reduced.

FIG. 6 is a flowchart showing a modification of FIG. As shown in the figure, steps S8 and S9 are added as compared with FIG. In step S8, it is confirmed whether or not the entire packet has been transmitted, and if there is untransmitted data constituting the same packet, the process proceeds to step S8.
Proceed to 9 to attempt transmission of this data. If all data has been transmitted, the process ends.

In step S9, the write inhibit signal 81 from the output buffer 8 is monitored. If the write inhibit signal 81 is in the write inhibit state, the transmission of the non-real time data is terminated.
If not, the process returns to step S5. FIG. 7 is a diagram showing a modification of FIG. As shown in the figure, as compared with FIG.
Is additionally provided.

When the traffic distribution unit 3 writes the non-real-time data to the NRT memory 4, the timer 45
The address management unit 42 notifies this by the write notification 46, thereby generating a write time and storing the write time as a log. The timer 45 monitors the current time minus the write time, and when the time exceeds the specified threshold value, transmits the timer excess of the non-real time data to the address management unit 42 as the timer excess notification 47. . The threshold may have hysteresis.

The address management section 42 notifies the transmission selection signal generation section 6 of this request as a storage amount notification 43 or another signal in a pseudo manner. The transmission selection signal generator 6 permits transmission of the corresponding non-real-time data based on this information by performing the same processing as when the storage amount is increased. In a protocol that needs to receive the delivery confirmation within a certain time, the timer 45
By suppressing the amount of delay using, it is possible to reduce the network use efficiency due to the occurrence of retransmission.

As described above, it is of course possible to simultaneously realize the embodiment shown in FIG. 1 and the modified examples shown in FIGS. Further, a transmission device mainly using ATM as a transmission technology is assumed, but it is naturally possible to apply to general packet transfer.

[0044]

As described above, according to the present invention,
The received traffic is discriminated into real-time data and non-real-time data, real-time data is minimized in delay, non-real-time data is discarded in minimum, non-real-time data is stored in FIFO memory, and real-time data is Non-real-time data is transferred with priority, and non-real-time data stored at a time when no real-time data exists is transferred.

Also, non-real-time data is not unilaterally treated as low priority, and when the amount of non-real-time data stored / accumulation time increases, real-time data can be discarded or delayed. The transfer of non-real-time data can also be realized at the same time.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a schematic configuration of a traffic characteristic-based optimized transfer system according to the present invention.

FIG. 2 is storage amount information 4 formed by an address management unit 42;
FIG.

FIG. 3 is a flowchart illustrating an operation of a transmission selection signal generator 6 in FIG. 1;

FIG. 4 is a diagram showing a modification of FIG. 1;

FIG. 5 is a diagram showing another modification of FIG. 1;

FIG. 6 is a flowchart showing a modification of FIG. 3;

FIG. 7 is a diagram illustrating a modification of FIG. 1.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Input signal 2 ... Traffic discrimination part 3 ... Traffic distribution part 4, 7 ... NRT memory 5 ... Transmission traffic selection part 6 ... Transmission selection signal generation part 8 ... Output buffer 21 ... Traffic discrimination signal 31, 32, 44, 51 ... Outputs 41, 71 ... Storage elements 42, 72 ... Address management unit 43 ... Storage amount information 45 ... Timer 61 ... Transmission selection signal 62, 64 ... NRT read permission signal 81 ... Write inhibit signal

Claims (10)

[Claims] A traffic discriminating unit for discriminating received traffic into real-time data and non-real-time data in an traffic-specific optimized transfer system for optimally transferring mixed real-time data and non-real-time data; A traffic distribution unit that distributes the received traffic to real-time data and non-real-time data based on the determination information of the traffic determination unit; and an NRT that stores the non-real-time data distributed by the traffic distribution unit. A memory, a transmission selection signal generation unit that generates a transmission selection signal for real-time data or non-real-time data based on the discrimination information of the traffic discrimination unit and the storage amount information of the NRT memory; Of the real-time data from the traffic distribution unit or the non- Traffic characteristics by optimizing transfer system and a sending traffic selecting unit for selectively sends time data. 2. The transmission selection signal generation section gives priority to transmission of real-time data in principle, and when a large amount of non-real-time data is stored according to the storage amount information of the NRT memory, the transmission selection signal generation section generates the real-time data. The traffic-specific optimized transfer system according to claim 1, wherein the transmission is distributed, and the transmission of the non-real-time data is inserted between transmissions of the distributed real-time data. 3. The transmission selection signal generator determines that a large amount of non-real time data is accumulated when the ratio of the used memory amount to all the NRT memories exceeds a certain threshold value. 3. The traffic characteristic optimized transfer system according to claim 2, wherein the threshold value is provided with hysteresis. 4. The transmission selection signal generator according to claim 1, wherein the transmission selection signal generator allows the transmission traffic selector to transmit the non-real-time data when there is no reception of the real-time data. Optimized transfer system by traffic characteristics. 5. The traffic-specific optimized transfer according to claim 1, wherein the traffic discriminating unit discriminates between real-time data and non-real-time data by discriminating an AAL type. system. 6. The optimized transfer system according to claim 1, wherein the NRT memory comprises a FIFO. 7. The NRT memory assigns priorities to non-real-time data and classifies and accumulates the data. The transmission selection signal generator controls reading of non-real-time data from the NRT memory based on the priority. 2. The method of claim 1, wherein
4. The optimized transfer system according to traffic characteristics described in 1. 8. An output buffer connected to the transmission traffic selector, wherein the output buffer is connected to the NR.
The information is read as a set from the T memory, and the transmission selection signal generation unit monitors a write inhibit signal from the output buffer, and terminates transmission of non-real-time data when write inhibit is performed. The optimized transfer system according to traffic characteristics according to claim 1, wherein 9. A timer is provided in the NRT memory, the timer monitors a writing time of non-real-time data to the NRT memory, and when the writing time exceeds a specified threshold, the timer 3. The traffic characteristic-based optimized transfer system according to claim 2, wherein the transmission selection signal generation unit determines that a large amount of non-real-time data is accumulated, and the threshold is provided with hysteresis. 10. A traffic characteristic-based optimized transfer method for optimally transferring mixed real-time data and non-real-time data, wherein a step of discriminating received traffic into real-time data and non-real-time data is provided. Distributing the received traffic to real-time data and non-real-time data based on the received information; and storing the distributed non-real-time data. Generating a transmission selection signal of real-time data or non-real-time data based on the amount information; and selecting distributed real-time data or accumulated non-real-time data according to the generated transmission selection signal. And a step of transmitting the optimized transmission according to traffic characteristics.