JP3445876B2 - Frame relay terminal, control device therefor, and communication system - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a terminal, a control device therefor, and a communication system using them, and more particularly to avoid receiving a congestion notification for congestion recovery control and improve the average value of frame transmission throughput. Frame relay terminal and its control device, and a communication system using these.

[0002]

2. Description of the Related Art CCITT (International Telegraph a
nd Telephone Consultative Committee)
Networks (frame relay networks) and terminals (frame relay terminals) that perform communication in the frame relay format are known.
Some frame relay terminals perform congestion recovery control when receiving a congestion notification indicating that the frame relay network originated congestion.

The congestion notification from the frame relay network is made by the BECN (Back
This is performed by setting the ward Explicit Congestion Notification) bit to "1" or by sending a CLLM (Consolidated Link Layer Manengement) frame from the frame relay network.

The BECN bit is set to "1" when there is a frame to be transmitted from the frame relay network to the frame relay terminal when the frame relay network detects a congestion state. In this case, the frame relay network transmits the B of a frame transmitted from another frame relay terminal and should be transmitted to the frame relay terminal.
The ECN bit is set to "1". The BECN bit is set to a predetermined bit position which is predetermined in each frame. Therefore, in this case, the congestion notification is piggybacked on the frame to be transmitted to the frame relay terminal.

The CLLM frame is transmitted from the frame relay network when there is no frame to be transmitted from the frame relay network to the frame relay terminal at the time when the frame relay network detects the congestion state. in this case,
Since the congestion notification by the above method cannot be performed, the frame relay network itself creates a CLLM frame for notification of the congestion and transmits the CLLM frame to the frame relay terminal.

When the frame relay terminal performing the congestion recovery control receives the congestion notification according to any one of the above methods, it reduces the frame transmission throughput to a predetermined value. The transmission throughput is represented by bps (bit per second). For example, if the frame relay terminal is a CIR (Committed
When a congestion notification is received during communication at a transmission throughput equal to or higher than the Information Rate), the frame relay terminal sets the transmission throughput of its own frame to C
Lower to IR. The CIR is the minimum amount of communication guaranteed by the contract, and when the frame relay network is in a normal state, communication with this value is reliably performed without discarding frames.

[0007] Therefore, the frame transmission throughput in the conventional frame relay terminal for performing congestion recovery control is
It was controlled as shown in FIG. In FIG. 25,
The horizontal axis represents time, and the vertical axis represents the frame transmission throughput.

The frame relay terminal which performs the congestion recovery control starts frame transmission and gradually increases the transmission throughput, as shown by the solid line in FIG. The time interval for increasing the transmission throughput and the amount of increase are variously set in each frame relay terminal. Delivery throughput is typically increased to values above the CIR. The CIR value is shown by the dotted line A. The frame relay terminal receives the congestion notification at the time T1 when transmission is performed at a certain transmission throughput. The point at which the congestion notification is received is not fixed, and depends on the occurrence of the congestion state in the frame relay network.

[0009] For example, as shown in the figure, when the frame relay terminal is communicating at the transmission throughput of CIR or more at T1, the frame relay terminal which performs the congestion recovery control that has received the congestion notification determines the transmission throughput to the CIR.
Lower to. Then, again, the frame relay terminal
The transmission throughput is gradually increased from R. In this way, the frame relay terminal that performs conventional congestion recovery control,
When the congestion notification is not received, the sending throughput is gradually increased, and when the congestion notification is received, the sending throughput is lowered to CIR.

[0010]

According to the above-described conventional technique, the frame transmission terminal in the frame relay terminal which performs the congestion recovery control has an average of all the transmission amounts within that period when a sufficiently long time is considered. Becomes
This value is shown by the dotted line B in FIG.

However, once the congestion notification is received, the CI
The transmission throughput drops to R. That is, although high transmission throughput can be obtained immediately before the reception time point T1 (and T2) of the congestion notification, when considering a sufficiently long time, the transmission throughput of the frame relay terminal performing the congestion recovery control (shown by the dotted line B). There was a problem that the average value of the sending amount) was not very large. According to a study by the present inventor, it is preferable to maintain a relatively high transmission throughput in a range in which it is possible to predict that a congestion notification is not received with a certain certainty. It turns out that it can be raised.

Further, there is a delay D before the congestion notification reaches from the frame relay network to the frame relay terminal, as shown in FIG. Therefore, the frame relay terminal that receives the congestion notification immediately determines the transmission throughput to the CI.
Even when it is reduced to R, the amount of frames corresponding to the shaded area in the figure is transmitted between the frame relay network issuing the congestion notification and the frame relay terminal reducing the transmission throughput. .

However, the frame transmitted from the frame relay terminal in such a period reaches the frame relay network which is already in the congestion state. Therefore, such a frame may be discarded in the congested frame relay network. In this case, since the frame is retransmitted depending on the communication protocol, there is a problem that the communication efficiency further deteriorates.

Separately from the above, the conventional frame relay terminal which performs the congestion recovery control, in the control of the decrease and increase of the transmission throughput, the type of frame to be transmitted or the type of communication (hereinafter, simply referred to as communication mode). Was never considered.

However, according to the study of the present inventor, it has been found that the congestion recovery control in consideration of the communication mode can increase the average value of the transmission throughput when a sufficiently long time is considered. . For example, in the case of communication in which a fixed amount of frames are continuously transmitted, this transmission itself causes congestion in the frame relay network, and therefore it is conceivable that congestion notification is received from the frame relay network. In this case, it has been found that the average value of the transmission throughput for a sufficiently long time can be increased by avoiding receiving the congestion notification from the frame relay network by suppressing the transmission throughput to some extent in advance. Further, for example, in the case of communication in which a large number of frames are intermittently repeated at a time, it is unlikely that this transmission will cause congestion in the frame relay network, and even if a temporary congestion occurs, the intermittent It is considered that the congestion state disappears promptly by the end of the automatic transmission. In this case, it has been found that sending the frame with the high sending throughput can contribute to increasing the sending throughput considered for a sufficiently long time.

The above is based on the knowledge of the present inventor that the average value of the transmission throughput is improved by not receiving the congestion notification as much as possible. However, further studies by the present inventor showed that in certain cases, even if congestion notification is received, the elements related to the occurrence of congestion such as the state of the frame relay network, the state of communication, and the mode of communication. It was found that the average value of the transmission throughput can be increased by following the value of the transmission throughput.

That is, in the case of the communication mode in which the traffic fluctuation is relatively fast, controlling the sending throughput so that the congestion notification is received as little as possible means that the sending throughput cannot keep up with the speed of the traffic fluctuation. Therefore, as a result, although the congestion notification is not received, the opportunity to communicate with a larger transmission throughput is lost. In this case, the average value of the transmission throughput becomes small. On the other hand, when the transmission throughput is made to quickly follow the fast traffic fluctuation, as a result, it is considered that the average value of the transmission throughput can be increased without receiving much congestion notification.

The present invention is based on the knowledge of the present inventor as described above, and controls the sending throughput so that the congestion notification is not received as much as possible, and the sending throughput follows the factors related to the occurrence of congestion. The average value of the transmission throughput is improved by rapidly changing the transmission throughput.

It is an object of the present invention to provide a frame relay terminal capable of increasing the average value of transmission throughput, its control device, and a communication system using these.

Another object of the present invention is to provide a frame relay terminal which controls transmission throughput based on the number of times congestion notification is received. It is another object of the present invention to provide a frame relay terminal that can reduce the number of congestion notifications received as much as possible to reduce congestion recovery control and frame retransmission.

Another object of the present invention is to provide a frame relay terminal which controls transmission throughput according to a communication mode. It is another object of the present invention to provide a frame relay terminal that controls the transmission throughput dynamically by following the factors related to congestion occurrence.

It is another object of the present invention to provide a frame relay terminal which controls to dynamically change the time interval for performing the processing for changing the transmission throughput according to the communication mode.

Another object of the present invention is to provide a terminal capable of increasing the average value of the transmission throughput, its control device, and a communication system using these terminals.
Another object of the present invention is to provide a transmission throughput control method capable of increasing the average value of the transmission throughput.

[0024]

FIG. 1 is a block diagram of the first principle of the present invention, and shows a frame relay terminal and its control device according to the present invention and a communication system using these. This is to control the congestion notification to be received as little as possible by statistically recording and processing the congestion notification.

In FIG. 1, this communication system includes a frame relay network 1, a plurality of frame relay terminals 3, and a physical line 2 connecting each of these and the frame relay network 1.
Consists of. This communication system performs congestion recovery control.
For this reason, the frame relay network 1 notifies the frame relay terminal 3 of congestion when it is in a congestion state. When receiving the congestion notification from the frame relay network 1, the frame relay terminal 3 executes the congestion recovery control.
The frame relay terminal 3 performs transmission throughput control in order to reduce the number of congestion notifications received from the frame relay network 1 as much as possible.

The frame relay terminal 3 includes a transmission throughput control device 4 for performing transmission throughput control and congestion recovery control. The transmission throughput control device 4 includes a transmission throughput management unit 5, a frequency table 7, a transmission throughput measuring unit 8, a congestion notification monitoring unit 9, and a mode recognition processing unit 1.
4 is provided.

The sending throughput measuring unit 8 monitors the sending throughput of frames to the frame relay network 1. The congestion notification monitoring unit 9 monitors the reception of the congestion notification from the frame relay network 1. The sending throughput management unit 5 creates the frequency table 7 based on the results of the monitoring by the sending throughput measuring unit 8 and the congestion notification monitoring unit 9, updates the value of the sending throughput, and sends the frame with the updated sending throughput. I do. In updating the transmission throughput, the transmission throughput management unit 5 determines the maximum value of the transmission throughput of the frame (non-congestion notification transmission throughput) by using the frequency table 7, and sets the value of the transmission throughput within the maximum value. Update. That is,
Suppression control is performed by the maximum value of sending throughput.

The mode recognition processing unit 14 recognizes the transmission mode of the frame relay terminal, and based on this, determines whether or not to update the transmission throughput within the range of the maximum value of the transmission throughput. That is, the transmission throughput suppressing control by the transmission throughput management unit 5 is enabled or disabled.

FIG. 2 is a block diagram of the second principle of the present invention, showing a frame relay terminal according to the present invention, a control device therefor, and a communication system using these. This is to control the transmission throughput by dynamically changing the transmission throughput by following the factors related to the occurrence of congestion.

The communication system of FIG. 2 has a configuration similar to that of FIG. 1 and performs the same congestion recovery control as that of FIG. That is, when the frame relay terminal 3 receives the congestion notification from the frame relay network 1, the frame relay terminal 3 performs the transmission throughput control in order to reduce the number of times of receiving the congestion notification as much as possible.

The transmission throughput control device 4 of the frame relay terminal 3 of FIG. 2 comprises a transmission throughput management unit 5, a congestion notification monitoring unit 9, a mode recognition processing unit 14 and a dynamic decision processing unit 25.

The congestion notification monitor 9 monitors the reception of the congestion notification from the frame relay network 1. Dynamic decision processing unit 25
Is based on the result of monitoring by the congestion notification monitoring unit 9,
Determine the maximum value of sending throughput. That is, the dynamic determination processing unit 25 reduces the maximum value of the transmission throughput by the value of the reduction amount obtained by the predetermined calculation when the congestion notification is received, and makes it smaller than the current value, and when the congestion notification is not received. The maximum value of the transmission throughput is made larger than the current value by the increment value obtained by the predetermined calculation. The transmission throughput management unit 5 causes the frame relay terminal to transmit the frame at the maximum value of the transmission throughput determined by the dynamic determination processing unit. That is, the suppression control is performed according to the maximum value of the transmission throughput.

The mode recognition processing unit 14 recognizes the transmission mode of the frame relay terminal, and based on this, determines the time interval for performing the processing for increasing the maximum value of the transmission throughput when the congestion notification is not received. .

[0034]

FIG. 3 is a diagram for explaining the first operation of the present invention, and shows the frame relay terminal shown in FIG. 1, its control device, and a communication system using these. In particular, FIG. 3A shows the determination of the non-congestion notification sending throughput.
(B) shows the transmission throughput control.

As shown in FIG. 3A, the transmission throughput management unit 5 determines the transmission throughput for each value of the transmission throughput based on the results of monitoring by the transmission throughput measuring unit 8 and the congestion notification monitoring unit 9. The frequency table 7 in which the number of times the congestion notification is received (reception frequency) is recorded is created.

As shown in FIG. 3A, the frequency table 7 has a tendency that, in most cases, the number of times congestion notifications are received rapidly increases as the value of the transmission throughput increases. Therefore, in the region R0 where the number of times of receiving the congestion notification is still “0”, it is expected that the probability of receiving the congestion notification is low in the future. On the other hand, in the region R1 in which the number of times of receiving the congestion notification is “1” or more, it is expected that the probability of receiving the congestion notification is high in the future. Therefore, by setting the transmission throughput in the region R0 in which the number of times of receiving the congestion notification is “0”, the probability of receiving the congestion notification can be made extremely small. That is, it is predicted with certainty that the congestion notification will not be received.

As a result, the transmission throughput management unit 5
Can set the sending throughput to an optimum value, that is, the maximum value (non-congestion notification sending throughput) within a range in which it can be predicted with certainty that the congestion notification will not be received. Therefore, the average value of the transmission throughput can be increased.

As shown by the solid line in FIG. 3 (B), the frame relay terminal 3 starts frame transmission and gradually increases the transmission throughput until the transmission throughput reaches the non-congestion notification transmission throughput. Maintains the value and suppresses the transmission throughput so that it does not exceed the value.

Since this non-congestion notification sending throughput is the maximum value that can be predicted within a certain certainty that the congestion notification will not be received, the frame relay terminal is unlikely to receive the congestion notification. Therefore, the number of times that the control of sharply reducing the transmission throughput due to the reception of the congestion notification is performed can be extremely reduced, so that the transmission throughput management unit 5 sets the transmission throughput to a relatively high value as shown in FIG. 3B. Can be maintained.

Although there is a delay until the congestion notification reaches from the frame relay network 1 to the frame relay terminal 3, the opportunity itself for receiving the congestion notification can be extremely reduced. It is possible to reduce the possibility that the frame transmitted by the frame relay terminal 3 after the congestion notification is transmitted is discarded in the frame relay network 1. Therefore, the number of times of frame retransmission according to the communication protocol can be extremely reduced,
It is possible to prevent deterioration of communication efficiency.

On the other hand, the mode recognition processing unit 14 determines that the frame transmission mode is a predetermined (first) mode, for example, a mode in which a fixed amount of data is continuously transmitted.
By enabling the transmission throughput suppression control by the transmission throughput management unit 5, the transmission throughput is suppressed below the non-congestion notification transmission throughput. This makes it possible to avoid receiving the congestion notification. In addition, when the frame transmission mode is another predetermined (second) mode, for example, in a mode in which the transmission of a large amount of data is repeated intermittently, the transmission throughput suppression control by the transmission throughput management unit 5 is performed. By disabling, the frame is transmitted with a high transmission throughput without suppressing the transmission throughput below the non-congestion notification transmission throughput. This can contribute to the improvement of the average value of the transmission throughput.

As described above, as a result of the statistical processing of the congestion notification regarding the transmission throughput, the average value of the transmission throughput in the frame relay terminal 3 can be set to a sufficiently large value when considering a sufficiently long time. The average value of the transmission throughput management unit according to the present invention is
In the value of CIR shown by dotted line A in FIG. 3 (B), and by a value sufficiently larger than the average value of the transmission throughput for a sufficiently long time in the frame relay terminal which performs the conventional congestion recovery control shown by dotted line B. is there.

In the frame relay terminal 3 as well,
When the congestion notification is received, the congestion recovery control is performed to reduce the transmission throughput to a predetermined value (a new non-congestion notification transmission throughput determined by the reception of the congestion notification). However, when considering a sufficiently long time, the number of times of receiving the congestion notification itself can be extremely reduced, so that the average value of the transmission throughput can be set to a sufficiently large value.

FIG. 4 is a diagram for explaining the second operation of the present invention, showing the frame relay terminal and its control device shown in FIG. 2 and a communication system using them, and showing the transmission throughput management processing flow thereof.

As shown in FIG. 4, the frame relay terminal 3
When the frame is received (S51), the congestion notification monitoring unit 9
Is checked whether it is a congestion notification (S52). If it is a congestion notification, the maximum value of the transmission throughput is made smaller than the current value by the value of the reduction amount obtained by the predetermined calculation by the dynamic determination processing unit 25 (S53), and the transmission throughput management unit 5 The frame relay terminal 3 is caused to transmit a frame at the reduced maximum value of the transmission throughput (S5).
4).

On the other hand, if it is not a congestion notification, the number of frames received by the transmission throughput management unit 5 is counted (S
55), and it is checked whether or not the count value is larger than the predetermined value n (S56). If it is smaller, S51 and the subsequent steps are repeated without performing the increasing process for increasing the maximum value of the transmission throughput. If it is larger, the maximum value of the transmission throughput is increased by a value up of the increase amount obtained by the predetermined calculation by the dynamic determination processing unit 25 than the current value (S57), and the maximum value of the transmission throughput is increased. The transmission throughput management unit 5 executes S54.

As a result, the transmission throughput management unit 5
Can dynamically set the transmission throughput to an optimum value, that is, a value according to the state of the frame relay network 1. Therefore, the transmission throughput that quickly follows the state of the frame relay network 1 can be set, and the average value of the transmission throughput can be increased. On the other hand, the mode recognition processing unit 14 determines that the frame transmission mode has a predetermined (first
2) mode, for example, in a mode in which a fixed amount of data is continuously transmitted, the time interval for the process of increasing the transmission throughput by the dynamic determination processing unit 25 is lengthened. As a result, it is possible to increase the transmission throughput during continuous data transmission and avoid receiving the congestion notification due to this. In addition, the frame transmission mode is set to another predetermined (second
2) mode, for example, in a mode in which sending a large amount of data at one time is repeated intermittently, the time interval of the process of increasing the maximum value of the sending throughput by the dynamic decision processing unit 25 is shortened. As a result, the transmission throughput can be promptly increased at the time of intermittent data transmission, which can contribute to the improvement of the average value of the transmission throughput.

As described above, as a result of the processing of tracking the transmission throughput of the elements related to the congestion notification, the average value of the transmission throughput in the frame relay terminal 3 should be a sufficiently large value when considering a sufficiently long time. You can

The above-described statistical processing of congestion notification is extremely effective when the traffic fluctuation is gentle, but when the traffic fluctuation is abrupt, at what time is the congestion notification affected? I do not know. That is, the latest state (only) of the frame relay network 1 cannot be reflected in the transmission throughput. On the other hand, particularly when the traffic fluctuation is large or fast, the average value of the transmission throughput can be increased by dynamically changing the transmission throughput and promptly following the traffic fluctuation.

[0050]

【Example】

(First Embodiment) A first embodiment of the present invention will be described with reference to FIGS. This embodiment corresponds to the first principle of the present invention shown in FIG. That is, this is an example of statistically processing the congestion notification. The frame relay terminal 3 of this embodiment is
The transmission throughput is controlled so as to maintain a relatively high transmission throughput within a range in which it can be predicted with certainty that the congestion notification is not received, and congestion recovery control is performed when the congestion notification is received from the frame relay network 1. .
The frame relay terminal 3 of this embodiment does not include a processing unit corresponding to the mode recognition processing unit 14.

FIG. 5 is a block diagram of an embodiment, and shows a frame relay terminal 3, its transmission throughput control device 4, and a communication system for performing communication in the frame relay format. The communication system includes a frame relay network 1 and a frame relay terminal 3
Consists of. Frame relay network 1 and frame relay terminal 3
And the physical line 2 are connected to each other. On the physical line 2, a virtual communication path (path), that is, a PVC (Perman)
ent Virtual Circuit) 21 is stretched. The PVC 21 is provided symmetrically.

More specifically, the communication system is constructed as shown in FIG. As shown in FIG. 6A, a plurality of (four) frame relay terminals 3 are connected to the frame relay network 1 via the physical line 2. Each frame relay terminal 3 is distinguished by its terminal number # 1 to # 4. Note that, for example, the frame relay terminal 3 having the terminal number # 1 will be referred to as a frame relay terminal # 1.

As shown in FIG. 6B, the frame relay network 1 is composed of a plurality (two) of exchanges 101. The physical lines 2 connect between the exchanges 101. Each exchange 101 is distinguished by its exchange number # 1 and # 2. In addition, for example, the exchange 101 having the terminal number # 1 will be referred to as exchange # 1.

A PVC 21 is provided between the frame relay terminals 3 having the terminal numbers # 1 to # 4, as shown in FIG. 6 (B). Each PVC 21 has its PVC number # 1 to # 4
Distinguished by. In addition, for example, PV of PVC number # 1
C21 will be referred to as PVC # 1.

PVC # 1 and PVC # 2 are provided symmetrically on the physical line 2. That is, the PVC # 1 reaches the frame relay terminal # 3 from the frame relay terminal # 1 via the exchanges # 1 and # 2. The PVC # 2 reaches the frame relay terminal # 1 from the frame relay terminal # 3 via the exchanges # 2 and # 1. This enables bidirectional communication between the corresponding frame relay terminals # 1 and # 3.

Communication between the frame relay terminal # 1 and the frame relay terminal # 3 is performed by the frame relay terminal # 1.
This is possible by sending a frame addressed to the frame relay terminal # 3 to the VC # 1, and the frame relay terminal # 3 sending a frame addressed to the frame relay terminal # 1 to the PVC # 2. The frame relay terminal # 1 receives various data transmitted from the frame relay network 1 via the PVC # 2. This data includes congestion notification and frame relay terminals #
3 includes the data sent from The frame relay terminal # 1 transmits various data to the frame relay network 1 via the PVC # 1. This data includes data to be transmitted to the frame relay terminal # 3. PVC
The same applies to communication between # 3 and PVC # 4, and between frame relay terminal # 2 and frame relay terminal # 4.

As is clear from the above description, the configuration of the communication system shown in FIG. 6 shows the minimum configuration as an example. Therefore, in the communication system, more frame relay terminals 3 are connected to the frame relay network 1, and many PVCs 21 are provided between them.

In frame relay network 1, switch # 1
From the frame relay terminals # 1 and # 2 to the PVC
The frames passing through # 1 and # 3 are sent to the frame relay terminals # 3 and # 4. At this time, for example, exchange #
When the processing amount in 1 increases and congestion occurs, the exchange # 1 notifies the frame relay terminals # 1 and # 2 of the congestion. This congestion notification is, for example, PVC # 2 and #.
A predetermined bit for notification of congestion in a frame passing through 4 (reverse frame), for example, the BECN bit is set to "1".
And by doing. The exchange # 1 also notifies the frame relay terminals # 3 and # 4 of congestion. This congestion notification is, for example, FECN (Forward Explicit Con) of a frame (forward frame) passing through PVCs # 1 and # 3.
gestionNotification) bit is set to "1".

When the congestion notification is performed, if there is no backward frame to be sent to the frame relay terminal # 1 (frame passing through the PVC # 2 sent from the frame relay terminal # 3), for example, the exchange # 1 is CLLM
A frame is created and sent to the frame relay terminal # 1. As a result, congestion notification is performed. The same applies to the other frame relay terminals # 2 to # 4.

In the backward frame, the BECN bit is provided at a predetermined position in the frame (see FIG. 14). The FECN bit of the forward frame is provided at a position substantially similar to the BECN bit of the backward frame (see FIG. 14). The backward frame viewed from the frame relay terminal # 1 is a frame sent in the opposite direction to the data sending direction. Also, frame relay terminal #
The forward frame viewed from 1 is a frame sent in the same direction as the data sending direction.

Frame relay terminal # 1 that received the congestion notification
Through # 4, congestion recovery control is performed. That is, the frame relay terminals # 1 to # 4 control the transmission throughput to drop to a predetermined value (non-congestion notification transmission throughput newly determined by the congestion notification). This allows
Since the number of frames sent to the exchange # 1 is reduced, the exchange # 1 recovers from the congestion state.

When the switch # 1 recovers from the congestion state, it stops suspending the BECN bit of the backward frame from "1" (sets the BECN bit to "0"). The same applies to the FECN bit of the forward frame and the CLLM frame. The frame relay terminal # 1 controls to gradually increase the transmission throughput from a predetermined value when it does not receive a congestion notification such as a backward frame whose BECN bit is "1".

The frame relay terminal 3 performs such congestion recovery control, but in order to minimize the number of times and maintain a relatively high transmission throughput, the frame relay terminal 3 transmits the frame in advance before receiving the congestion notification. Adjust the throughput to the desired value. For this reason, the frame relay terminal 3 obtains the maximum value of the transmission throughput within a range in which it can be predicted with certainty that the congestion notification is not received, and controls the transmission throughput to be equal to or less than this value.

Therefore, as shown in FIG. 5, the frame relay terminal 3 is composed of a transmission throughput control device 4, a communication control unit 10 and a data processing unit 13. For convenience of description, the frame relay terminal 3 is assumed to be the frame relay terminal # 1 shown in FIG. 6, for example. Further, the frame relay terminal 3 is a data processing device which itself executes data processing independently, and includes a CPU (central processing unit) and a control program stored in a memory. The control program includes, for example, a transmission throughput control program, a communication control program, a data processing program, and the like.

The data processing unit 13 carries out predetermined data processing, and thereby the frame transmission unit 11 of the communication control unit 10
Create a frame to be transmitted in (transmission frame). The transmission frame (see FIG. 14) includes data to be transmitted at the predetermined position. The transmission frame includes the terminal number (for example, # 3) of the frame relay terminal 3 of the transmission destination. The data processing unit 13 sends the created transmission frame to the frame transmission unit 11 and requests its transmission.

Further, the data processing unit 13 is the communication control unit 10.
Data processing is performed on the frame (reception frame) received by the frame receiving unit 12 of FIG. For this,
The frame receiving unit 12 sends the received frame (see FIG. 14) to the data processing unit 13. The reception frame includes the terminal number (for example, # 3) of the frame relay terminal 3 that is the transmission source. The data processing unit 13 analyzes the received frame, extracts the data included in the predetermined position, and performs a predetermined process on this data.

The communication control unit 10 is connected to the frame relay network 1 via the physical line 2 and sends and receives frames and the like to and from this. For this purpose, the communication controller 10 includes a frame transmitter 11 and a frame receiver 12.

The frame transmission section 11 transmits a frame to the frame relay network 1 via the PVC 21 provided on the physical line 2. This frame is PVC # 1
Via frame relay terminal # 3. This frame is a forward frame for the frame relay terminal # 1. The transmission rate of data in the frame transmission unit 11, that is, the frame transmission throughput is measured by the transmission throughput measuring unit 8. The transmission throughput is a value determined by the transmission throughput management unit 5 (a value updated stepwise or a value of the non-congestion notification transmission throughput).

The frame receiving section 12 receives the frame sent from the frame relay network 1 via the PVC 21 provided on the physical line 2. This frame is PVC
It is sent from the frame relay terminal # 3 via # 2. This frame is a backward frame for the frame relay terminal # 1. The BECN bit of the frame received by the frame receiving unit 12 is monitored by the congestion notification monitoring unit 9. The FECN bit of the forward direction frame and the CLLM frame are similarly detected by the congestion notification monitoring unit 9
Monitored by.

The transmission throughput control device 4 comprises a transmission throughput management section 5, a frequency table 7, a transmission throughput measuring section 8 and a congestion notification monitoring section 9. The transmission throughput management unit 5 includes a frequency update processing unit 6. The frequency table 7 is managed by the transmission throughput management unit 5, and is provided in the memory of the frame relay terminal 3.

The transmission throughput control device 4 controls the transmission throughput of frames in the frame transmission section 11. For this purpose, the transmission throughput control device 4 monitors the frame transmission throughput in the frame transmission unit 11 and the reception of the congestion notification in the frame reception unit 12, and accumulates these monitoring results in the frequency table 7. Then, the transmission throughput control device 4 determines the maximum value of the transmission throughput (non-congestion notification transmission throughput) based on the frame transmission throughput of the frame transmission unit 11 and the frequency table 7 until then, and determines the maximum value or less. The value of the transmission throughput is updated within the range, and the frame is transmitted with the updated value.

When the frame receiving unit 12 receives the congestion notification, the transmission throughput control device 4 performs the congestion recovery control. Therefore, the transmission throughput control device 4 is also a congestion recovery control device included in the frame relay terminal 3. The sending throughput control device 4 monitors the reception of the congestion notification in the frame receiving unit 12, and in response to this reception, drops the value of the sending throughput to a predetermined value (a non-congestion notification sending throughput newly determined by the congestion notification). Then, the frame transmission unit 11 is caused to perform frame transmission with this value, and congestion recovery control is performed.

Further, the transmission throughput control device 4 causes the frequency update processing section 6 to update the frequency table 7. This update is a process of reducing the number of times of receiving the congestion notification accumulated in the frequency table 7 by a predetermined means at a predetermined cycle. For example, the number of times the backward frame is received is used to determine the reduction amount. In principle, the frequency table 7 stores all the number of past congestion notifications, but the frequency update processing unit 6 periodically reduces the number of congestion notifications by a predetermined amount.

First, the transmission throughput control performed by the transmission throughput control device 4 will be described. The sending throughput measuring unit 8 monitors the sending throughput of the frame in the frame sending unit 11, and notifies the sending throughput managing unit 5 of the current (at that time) sending throughput as a result of the monitoring. Therefore, the transmission throughput measuring unit 8 uses the frame relay terminal # via the PVC # 1, for example.
3. Monitor the current value of the forward frame's outgoing throughput to 3.

The congestion notification monitoring unit 9 includes a frame receiving unit 12
The reception of the congestion notification is monitored, and the number of congestion notifications received as a result of the monitoring is notified to the transmission throughput management unit 5. Note that the congestion notification is performed by the BECN bit “1”, the FECN bit “1”, and the CLLM frame as described above. However, for convenience, the congestion notification is performed by the BECN bit “1” in the following description. Shall be given. Therefore, the congestion notification monitoring unit 9 is, for example, P
The backward frame sent from the frame relay terminal # 3 via the VC # 2 is analyzed, and B at the predetermined position is analyzed.
Monitor whether the ECN bit is "1".

The transmission throughput management section 5 monitors the current transmission throughput of the frame transmission section 11 from the transmission throughput measurement section 8 and the congestion notification in the frame reception section 12 from the congestion notification monitoring section 9 (“BECN bit“ 1 ”) reception monitoring result and the frequency table 7
Accumulate in. The accumulation of the monitoring result in the frequency table 7 is always continued while the frame relay terminal 3 is connected to the frame relay network 1.

An example of the frequency table 7 is shown in FIG. The frequency table 7 divides the range of possible values of the transmission throughput into a plurality of areas in advance, and the BECN is set for each area.
The number of times the bit “1” is received is stored. The minimum value of the transmission throughput is 0 kbps (kilo b) which is the value before the start of transmission.
ps). The maximum value of the transmission throughput is theoretically equal to the physical line speed determined by the physical line 2.
The value of the physical line speed is, for example, 1.5 Mbps (mega bp).
s). In this frequency table 7, the range of possible values of the transmission throughput is 0 kbps to 1500 k
The bps is divided into 100 kbps to have 14 entries.

In the illustrated frequency table 7, 13000k
In the case of the transmission throughput of bps or more and less than 1400 kbps, it is recorded that "66" frames having the BECN bit of "1" have been received by that time.
Further, in the case of the transmission throughput of 14000 kbps or more and less than 1500 kbps, it is recorded that "80" frames having BECN bits of "1" have been received by that point.

If the contents of the frequency table 7 are graphed for the purpose of explanation, a graph as shown in FIG. 7B can be obtained, for example. In this graph, the horizontal axis represents possible values of the transmission throughput, and the vertical axis represents BEC.
It represents the number of receptions of N-bit “1”. Note that FIG.
The contents of the frequency table 7 in (A) and the graph in FIG. 7 (B) do not correspond.

In most cases, the graph of the transmission throughput vs. the number of times the BECN bit is "1" is received is shown in FIG. 7 (B).
As shown in (3), the number of BECN bit “1” receptions tends to increase rapidly as the transmission throughput increases. Therefore, the BECN bit is still "1".
It is expected that the probability of receiving the BECN bit of "1" will be low in the region R0 in which the number of receptions of "1" is "0". On the other hand, in the region R1 in which the number of times the BECN bit “1” is received is “1” or more, BECN will continue to be used.
It is expected that the probability of receiving a "1" in bits is high. Therefore, the probability of receiving the congestion notification can be made extremely small by setting the transmission throughput in the region R0 in which the number of times the BECN bit of "1" is received is "0". That is, it is predicted with certainty that the congestion notification will not be received.

The transmission throughput and the result of monitoring the reception of BECN bit “1” are sequentially accumulated in the frequency table 7. Therefore, the state of the frame relay network 1 and the number of times the BECN bit “1” is received by the frame relay terminal 3 depending on the state change with time, but this change can be reflected in the frequency table 7 sequentially. As a result, the sending throughput management unit 5 sets the sending throughput to an optimum value, that is, a value less than or equal to the maximum value of the non-congestion notification sending throughput in the range in which it can be predicted with certainty that the congestion notification will not be received. You can

For example, as shown in FIG. 7B, the monitoring result of the current transmission throughput from the transmission throughput measuring unit 8 is "768 kbps", and the congestion notification monitoring unit 9 detects the transmission throughput during this period. BE
The monitoring result of the number of times the CN bit is "1" is "10".
Suppose In this case, the transmission throughput management unit 5
Indicates a “768k” as indicated by the diagonal lines in FIG.
The monitoring result “10” is added to the content of “bps”. That is,
The transmission throughput management unit 5 uses the “70
The monitoring result “10” is added to the content of the entry “0 kbps or more and less than 800 kbps”. As a result, the transmission throughput versus the number of times the BECN bit is “1” is stored in the frequency table 7.

As can be seen from the above, the actual transmission throughput is determined by the value to be used for various reasons, and is set in detail, for example, "768 kbps". Therefore, the entries of the actual frequency table 7 are divided in a finer range, for example, in increments of 10 kbps or in increments of 1 kbps according to the value of the frequently used transmission throughput. As a result, it is possible to further finely control the transmission throughput according to the occurrence of congestion in the frame relay network 1 and optimize the transmission throughput. That is, in the range in which the congestion notification is not received, a larger transmission throughput can be set (as the non-congestion notification transmission throughput), and the average value of the transmission throughput can be increased.

The transmission throughput management unit 5 determines the value of the frame transmission throughput in the frame transmission unit 11 as
The value is increased stepwise by a predetermined value at predetermined time intervals. The time interval and the amount to be increased are given to the transmission throughput management unit 5 in advance according to the characteristics of the frame relay terminal 3 and the frame relay network 1. The transmission throughput management unit 5 sends the determined transmission throughput value to the frame transmission unit 11, and causes the frame transmission unit 11 to perform frame transmission at this transmission throughput value. For example, the value of the frame transmission throughput in the frame transmission unit 11 is increased as shown in FIG. That is, the transmission throughput is "0" before the start of transmission.
"kbps".

In this process, the transmission throughput management unit 5 determines, based on the transmission throughput of frames in the frame transmission unit 11 and the frequency table 7 up to that point.
Determines the value of outgoing throughput.

Specifically, the transmission throughput management unit 5
Sets a value that is larger than the value of the frame transmission throughput in the frame transmission unit 11 up to that point by a predetermined value as the “temporary value” of the new transmission throughput. Then, the transmission throughput management unit 5 searches the frequency table 7 in the ascending order of the transmission throughput using this “temporary value”, and determines a new value of the transmission throughput based on this search result.

That is, in the frequency table 7, the value of the first entry in which the BECN bit "1" is received one or more times is compared with the "temporary value". If the value of the entry is larger than the "temporary value", the "temporary value" is still BECN.
Since the number of times the bit "1" is received is 0 in the region R0, the "temporary value" is used as it is as a new transmission throughput value. On the other hand, when the value of the entry is less than or equal to the “temporary value”, the “temporary value” does not exist in the region R0 (the region R1 in which the number of times of reception is one or more times) is present. The minimum value is the new value of the transmission throughput.

This will be explained with reference to FIG. FIG. 7C is a diagram corresponding to FIG. 7B. The transmission throughput is gradually increased from "0 kbps".
That is, it moves to the right in the figure. At this point, the delivery throughput is in region R0. Then, the value of the transmission throughput is updated stepwise until the "temporary value" reaches the region R1. By repeating the update, the "temporary value" reaches the region R1. The lowest transmission throughput of the region R1 is set as the upper limit of updating. Beyond this value BEC
The probability of receiving an N-bit “1” rapidly increases. This value is the non-congestion notification sending throughput.

The non-congestion notification sending throughput is taken as the sending throughput within a range in which the probability of receiving the BECN bit "1" which is a congestion notification is sufficiently low, that is, within the range in which the congestion notification is not received with a certain certainty. It is the maximum value that can be obtained. By setting the sending throughput to a value equal to or less than the non-congestion notification sending throughput, it is possible to prevent the probability of receiving "1" of the BECN bit from increasing.

As a result of the above, the transmission throughput is
Unless an N-bit “1” is received, the value is gradually updated to a larger value. This update is performed step by step within a range equal to or less than the non-congestion notification sending throughput. The transmission throughput management unit 5 causes the frame transmission unit 11 to perform frame transmission with the updated transmission throughput value. For example, the value of the frame transmission throughput in the frame transmission unit 11 is increased as shown in FIG. That is,
The transmission throughput gradually increases from “0 kbps” before the start of transmission, exceeds the CIR at a certain point, and further gradually increases to the non-congestion notification transmission throughput and maintains this value.

Next, the congestion recovery control executed by the transmission throughput control device 4 when the BECN bit "1" which is a congestion notification is received will be described. Since the transmission throughput control device 4 performs the above-mentioned transmission throughput control, the transmission throughput is never made larger than the non-congestion notification transmission throughput. Therefore, BE
The value of the transmission throughput at the time when the CN bit “1” is received is always less than or equal to the value of the non-congestion notification transmission throughput.

Therefore, as shown in FIG. 8A, at the time of frame transmission at a transmission throughput considerably smaller than the non-congestion notification transmission throughput determined from the frequency table 7 (hereinafter referred to as old non-congestion notification transmission throughput). , BECN bit “1” is received.

Such a state occurs, for example, when the BECN bit "1" is received at an early stage while the transmission throughput is being increased stepwise from 0 kbps. The BECN bit “1” in this case is not caused by the frame relay terminal 3 concerned, but is caused by another frame relay terminal 3. Further, such a state occurs when the load of the exchange 101 becomes heavy after the non-congestion notification sending throughput is once determined by the frequency table 7, and it becomes impossible to respond to the sending at the non-congestion notification sending throughput.

More specifically, the above state occurs in the following cases. In FIG. 6B, frame relay terminal # 1
Through # 4, the frame relay terminal # 2 sends a frame to the frame relay terminal # 4 via the PVC # 3 while the non-congestion notification sending throughput is a sufficiently large value (for example, a value close to the physical line speed). It is assumed that the frame relay terminal # 1 starts transmitting a frame to the frame relay terminal # 3 via the PVC # 1 after a considerable delay. In this case, when the transmission throughput of the frame relay terminal # 1 has a relatively small value, the transmission throughput of the frame relay terminal # 2 becomes the non-congestion notification transmission throughput. Therefore, the exchange # 1 is in a congestion state mainly for processing the frame transmitted by the frame relay terminal # 2. Therefore, frame relay terminal # 1 (and #
2 to # 4) receive the congestion notification from the exchange # 1.
As a result, the frame relay terminal # 1 receives the congestion notification at the time when its transmission throughput has a relatively small value.

As described above, the transmission throughput measuring unit 8
Monitors the frame transmission unit 11 and notifies the transmission throughput management unit 5 of the current (at that time) transmission throughput. The congestion notification monitoring unit 9 monitors the frame receiving unit 12 and notifies the transmission throughput managing unit 5 of the number of times the BECN bit is “1” received. The transmission throughput management unit 5 accumulates these monitoring results in the frequency table 7. An example of the frequency table 7 is shown in FIG. The frequency table 7 of FIG. 8 (B) is compared with the frequency table 7 of FIG. 7 (A). In the frequency table 7 of FIG.
A frame whose ECN bit is “1” is, for example, 100
When the transmission throughput is kbps or more and less than 200 kbps, "y '" is received, and 300 kbps or more and 400 k
It is recorded that "y" pieces have been received when the transmission throughput is less than bps.

Since the value of the transmission throughput at the time when the BECN bit "1" is received is less than the value of the non-congestion notification transmission throughput, it is 100 kbps or more and 200 kps or more.
Reception of a BECN bit of "1" at a transmission throughput of less than bps does not precede a transmission throughput of 300 kbps or more and less than 400 kbps. Therefore, such a frequency table 7 first receives a BECN bit of "1" at a time point of 300 kbps or more and less than 400 kbps while increasing the transmission throughput, and ends the transmission of the frame at a transmission throughput slightly smaller than 300 kbps, for example. After that, while the transmission throughput is being increased again, the BECN bit is set to "1" in the transmission throughput of 100 kbps or more and less than 200 kbps.
Occurs when a message is received.

If the contents of the frequency table 7 are graphed for the sake of explanation, a graph as shown in FIG. 8A can be obtained, for example. Note that the contents of the frequency table 7 in FIG. 8B and the graph in FIG. 8A do not correspond. As can be seen from the graph shown in FIG.
The area R0 in which the number of times the bit "1" is received is "0" is extremely small, and the area R1 in which the number of times the BECN bit "1" is received is 1 or more is extremely large. Therefore, the value of the non-congestion notification sending throughput is also changed to a value considerably smaller than the non-congestion notification sending throughput shown in FIG.

As described above, the congestion recovery control when the BECN bit "1" is received in the transmission throughput of 100 kbps or more and less than 200 kbps while increasing the transmission throughput will be described.

The transmission throughput management unit 5 increases the value of the new transmission throughput by a predetermined value (given in the transmission throughput control program) from the value of the transmission throughput of the frame in the frame transmission unit 11 until then. Value of. Then, the transmission throughput management unit 5 searches the frequency table 7 using this “temporary value”. However, the BECN bit "1"
As a result, the number of times of receiving the entry of 100 kbps or more and less than 200 kbps is “y ′”. In this case, y '= 1. Therefore, the BECN bit is "1".
Value and the "temporary value" of the entry that received 1 or more times
As a result of the comparison with
kbps) becomes smaller than the “temporary value”. Therefore, the transmission throughput management unit 5 sets the minimum value of the entry, that is, the non-congestion notification transmission throughput, as a new transmission throughput value.

As a result, the transmission throughput of the frame relay terminal 3 is reduced and the number of frames to be transmitted is suppressed, so that the congestion of the frame relay network 1 can be recovered. On the other hand, while performing such congestion recovery control, the value of the transmission throughput is set to the maximum value that the transmission throughput can take within a range in which the probability of receiving the BECN bit “1” which is the congestion notification at that time is sufficiently low. be able to. In this embodiment, the congestion recovery control is thus performed simultaneously with the transmission throughput control.

The congestion recovery control is similarly performed when "y" BECN bits "1" are received at a transmission throughput of 300 kbps or more and less than 400 kbps while increasing the transmission throughput.

Next, the update processing of the frequency table 7 executed by the frequency update processing section 6 will be described. As aforementioned,
This update process is a process of reducing the number of times of receiving congestion notifications accumulated in the frequency table 7 by a predetermined means at a predetermined cycle. Further, the number of times the backward frame is received is used to determine the reduction amount.

The update process is performed for the following reason. As described above, the upper limit of the sending throughput is determined by the non-congestion notification sending throughput and cannot be exceeded. However, in the case of accumulating all the reception counts of past congestion notifications in the frequency table 7, the frequency table congestion notification sending throughput may decrease but not increase. Therefore, even if the congestion notification is no longer received at the once determined non-congestion notification sending throughput, the sending throughput cannot be updated to be higher than the non-congestion notification sending throughput. In addition, even after the non-congestion notification transmission throughput is once determined, even if the load on the exchange 101 is lightened and the frame relay terminal 3 does not cause congestion even if the frame is transmitted at a higher transmission throughput, The throughput cannot be updated more than the non-congestion notification sending throughput. Therefore, a process of reducing the number of times of receiving congestion notifications accumulated in the frequency table 7 is performed.

More specifically, as shown in FIG. 9, when the frame relay terminal 3 receives the congestion notification at the time when its transmission throughput is a relatively small value, the non-congestion notification transmission throughput determined by this is large. Need to raise to value. For example, as described above, when the cause of receiving the congestion notification is the frame transmission at a value close to the non-congestion notification transmission throughput by the frame relay terminal # 2, when the frame relay terminal # 2 finishes the transmission. Therefore, it is expected that the congestion state of the frame relay network 1 will be recovered. Therefore, processing for periodically increasing the value of the non-congestion notification sending throughput is executed.

The frequency update processing unit 6 receives the number of times the BECN bit "1", which is the congestion notification stored in the frequency table 7, is received based on the number of times the backward frame is received at each predetermined time. To reduce. The cycle of performing the reduction processing is set equal to the time interval for increasing the transmission throughput in the frame relay terminal 3, for example. When the timer starts, the frequency update processing unit 6 counts the number of receptions of backward frames. When the timer times out, the frequency update processing unit 6 ends this counting, restarts the timer, and repeats the same counting. To this end, the frequency update processing unit 6 includes a predetermined timer and counter (not shown).

The frequency update processing unit 6 obtains the number of times (reduction number) y to be reduced from the frequency table 7 by using the number of times the backward frame is received. When the number of receptions of backward frames from the start of the timer to the time up is x, the reduction number y = ax + b. Where a and b
Is a coefficient of a predetermined value and is empirically obtained.
The coefficients a and b are given to the frequency update processing unit 6 in advance as a transmission throughput control program.

The frequency update processing unit 6 subtracts the reduction number y obtained from the reception numbers stored in all the entries of the frequency table 7, and sets the value after the subtraction as the new content of each entry. Therefore, for example, the frequency table 7 shown in FIG. 8B is rewritten as the frequency table 7 shown in FIG. 9A. In the frequency table 7 shown in FIG. 9A, for example, the entries of 100 kbps or more and less than 200 kbps are rewritten from "y '" to "0" to 300 kbp.
The entries of s or more and less than 400 kbps are rewritten from "y" to "0". Also, for example, 130
The entry of 0 kbps or more and less than 1400 kbps is "6".
6 ”to“ (66-y) ”, 140
The entry of 0 kbps or more and less than 1500 kbps is "8".
It is rewritten from "0" to "(80-y)".

In this example, y> y 'and y>y''. Also, the subtraction result y '
If the values of -y and y ''-y are negative, "0" is recorded as shown. That is, if the number of BECN receptions of the entry (reception number item) is N, Max (0, N
-Y). Therefore, "0" or "N-
The larger value of "y" is recorded. y> y 'and y>
Even if y ″ does not hold, the contents of the above entry can be rewritten to “0” by repeating the subtraction process a plurality of times.

If the contents of the frequency table 7 are graphed for the sake of explanation, a graph as shown in FIG. 9B can be obtained, for example. The contents of the frequency table 7 in FIG. 9A and the graph in FIG. 9B do not correspond. As shown in the graph of FIG. 9B, the BECN bit “1” received at the time of the low transmission throughput.
The value y that exceeds the number of receptions of is reduced from all entries of the transmission throughput. As a result of this reduction processing, in the frequency table 7, the number of times the BECN bit “1” is received at the time of low transmission throughput is set to 0 times.

When the transmission throughput management unit 5 increases the transmission throughput stepwise after this update processing, the upper limit is not the value of the low non-congestion notification transmission throughput until then, but a new high non-congestion notification. It has been changed to the value of transmission throughput. As a result, the value of the transmission throughput can be set to the maximum possible value in the range where the probability of receiving "1" of the BECN bit is sufficiently low.

FIG. 10 is a frequency update processing flow. The frame receiving unit 12 receives the frame transmitted from the frame relay network 1 (S1).

The frequency update processing section 6 counts the number of backward frames received (S2). That is, assuming that the number of received frames is x, the value x + 1 obtained by adding "+1" to the number of received frames x up to then is set as a new value of x.

The frequency update processing unit 6 checks whether or not a predetermined time T has passed from the previous frequency update processing (S3), and if not, repeats S1 and subsequent steps. When the time has elapsed, the frequency update processing unit 6 obtains the reduction number y (S4).

Next, the frequency update processing unit 6 reduces the reduction number y calculated from all the entries (reception number items) of the frequency table 7 (S5). The frequency update processing is completed as described above, and the frequency update processing unit 6 is ready for the next frequency update processing.
Sets the number of received frames x to "0" and the timer value to "0"
(S6). After that, S2 and subsequent steps are repeated.

FIG. 9 is a transmission throughput management (and congestion recovery control) processing flow. The frame receiving unit 12 receives the frame transmitted from the frame relay network 1 (S11).

The congestion notification monitoring unit 9 checks whether or not the BECN bit of the frame is "1 (ON)" (S1).
2). If it is ON, the transmission throughput management unit 5 increments the BECN reception count of the entry corresponding to the transmission throughput at that point in the frequency table 7 by "+1" (S1).
3). After this, S14 to S16 are omitted and S17 is executed.

If not ON (OFF), the transmission throughput management unit 5 adds "+1" to the number of times the frame whose BECN bit has been "0 (OFF)" has been continuously received (the number of continuous reception). Is recorded as a new continuous reception count (S14). For this purpose, the transmission throughput management unit 5 includes, for example, a counter.

Next, the transmission throughput management unit 5 checks whether the number of continuous receptions is larger than a predetermined value n (S1
5) If not larger, S14 is repeated. The value n is given in advance to the transmission throughput management unit 5 as a transmission throughput control program, for example.

If it is larger, the transmission throughput management unit 5 updates the transmission throughput x'up to that time to a new transmission throughput x (S16). It should be noted that this value x is different from the above-mentioned BECN reception count x.

Next, the transmission throughput management unit 5 checks the frequency table 7 in order from the smallest transmission throughput (in ascending order) (S17), and the transmission throughput when the number of BECN receptions becomes larger than "0" for the first time. Is set as the non-congestion notification sending throughput Xmax (S18).

Further, the transmission throughput management unit 5 determines that the value x
Is compared with the value Xmax, and if x> Xmax, x =
Xmax is set (S19). If x> Xmax is not satisfied, the value of x remains the value updated in S16.

The frame transmission unit 11 receives the notification from the transmission throughput management unit 5 and receives a new transmission throughput x.
To transmit the frame to the frame relay network 1 (S2
0). After that, S11 and subsequent steps are repeated when a frame is received or a predetermined time elapses.

The frame relay terminal 3 changes its transmission throughput as follows by the above transmission throughput control and congestion recovery control. Unless the BECN bit "1" is received in S11, the frame relay terminal 3 uses the transmission throughput control to consecutively receive the BECN bit "0" for a predetermined number of times n, and the transmission throughput is stepwise by a value (xx). ') Increment by (x
> Xmax). Then, the transmission throughput becomes a relatively high value, and the non-congestion notification transmission throughput Xmax
When x> Xmax is reached, the frame relay terminal 3 maintains the value. That is, the non-congestion notification sending throughput Xmax is set as the upper limit of the sending throughput by controlling the sending throughput. After the transmission of this frame is completed, the frame relay terminal 3 starts transmitting another frame again, and gradually increases the transmission throughput by a value (xx ′). In this case, the upper limit of the update of the transmission throughput remains the previous non-congestion notification transmission throughput Xmax at this point. However, when the transmission throughput is considerably low, the frame relay terminal 3
Suppose that the BECN bit "1" is received in S11.

Reception of this BECN bit "1" is S1.
3 is immediately reflected in the frequency table 7. Therefore, in S18, the new non-congestion notification sending throughput Xmax is changed from the relatively high value of the previous non-congestion notification sending throughput to a considerably low value when the BECN bit "1" is received in S11. As a result, in S19, the transmission throughput is lowered to a new non-congestion notification transmission throughput Xmax having a considerably low value. Then, the frame relay terminal 3 sends a new non-congestion notification sending throughput Xmax having a considerably low value in S20.
To send a frame. That is, the congestion recovery control is performed using the transmission throughput suppression control.

After the transmission of this frame is completed, the frame relay terminal 3 starts transmitting another frame again. At this time, assuming that the predetermined time has not elapsed in S3 of FIG. 10, the upper limit of the update of the transmission throughput is
New non-congestion notification sending throughput Xma of considerably low value
It remains x.

On the other hand, if the predetermined time has elapsed in S3, the number of times of reception is reduced by y times from each entry of the frequency table 7 in S5. This allows
If the number of times the BECN bit “1” is received in S11 is “1” and y> 1, the content of the entry in the frequency table 7 is updated to “0”.
Therefore, in this case, the upper limit for updating the transmission throughput is
Non-congestion notification sending throughput X, which is a relatively high value
It has recovered to max.

As a result, the frame relay terminal 3 determines that S1
Unless a BECN bit "1" is received at 1,
Non-congestion notification sending throughput X, which is a relatively high value
The transmission throughput is increased stepwise, with max being the upper limit. Therefore, it is possible to transmit a frame with a relatively high value.

(Second Embodiment) A second embodiment of the present invention will be described with reference to FIGS. This embodiment is also shown in FIG.
It corresponds to the first principle of the present invention shown in FIG. In this embodiment, the frame relay terminal 3 is the frame relay router 2
It consists of zero. In this embodiment, the frame relay router 20
It is an example of controlling the transmission throughput by using a control code based on the transmission mode of the frame transmitted by. For this reason, the frame relay router 20 of the present embodiment has the control code recognition processing unit 1 corresponding to the mode recognition processing unit 14.
5 and a control code table 16.

FIG. 12 is a block diagram of an embodiment, showing a frame relay router 20, its transmission throughput control device 4, and a communication system for performing communication in the frame relay format. The communication system includes a frame relay network 1 and a frame relay router 20. Between the frame relay network 1 and the frame relay router 20, the frame relay network 1 of FIG.
Similarly to the connection between the frame relay terminal 3 and the frame relay terminal 3, the physical line 2 is connected, and a PVC 21 is provided on the physical line 2.

More specifically, the communication system is shown in FIG.
As shown in (A), a frame relay router 20 is connected to the frame relay network 1 via a physical line 2, and a data processing device 19 such as a personal computer is connected to the frame relay router 20 via a line 22. To be done. A plurality of frame relay routers 20 are connected to the frame relay network 1 as in the frame relay terminal 3 shown in FIG.

Between the two frame relay routers 20,
As shown in FIG. 6B, the PVC 21 is stretched. Communication between the frame relay routers 20 is performed by the frame relay router 20 sending out a frame to the PVC 21. When congestion occurs in the frame relay network 1, the exchange 101 notifies the frame relay router 20 of congestion in the same manner as in the above case.

A plurality of data processing devices 19 are connected to one frame relay router 20 via a line 22,
These make up a LAN (Local Area Network). Communication between the frame relay router 20 and the data processing device 19 connected to the frame relay router 20 is performed by, for example, TCP / IP (Transm).
It is performed in the form of packet communication according to a predetermined protocol such as ission Control Protocol / Internet Protocol).

Therefore, in the communication between the two data processing devices 19, the communication between the source data processing device 19 and the frame relay router 20 is, for example, TCP / IP.
Frame relay router 2 according to the packet format
Communication between the frame relay network 20 and the data processing device 19 on the receiving side is performed by, for example, TCP / I.
According to P, the packet format is used. The frame relay router 20 receives a packet conforming to TCP / IP from the data processing device 19, creates a frame (see FIG. 14) for storing the TCP / IP header and data of the received packet in a predetermined position, and creates the frame. It is sent to the frame relay network 1. The frame relay router 20, which has received the frame from the frame relay network 1, extracts the TCP / IP header and data from the frame, analyzes them, and transmits the TCP / IP.
The packet according to the above is created and sent to the data processing device 19 designated by the TCP / IP header.

The frame relay router 20 performs the transmission throughput control and the congestion recovery control in the same manner as the frame relay terminal 3 in transmitting the frame to the frame relay network 1, and updates the frequency table 7. As shown in FIG. 12, the frame relay router 20 includes a transmission throughput control device 4, a communication control unit 10, and a data processing unit 13. For convenience, the frequency update processing unit 6
Are not shown. The frame relay router 20
It is composed of a CPU (central processing unit) and a control program stored in a memory. The control program includes, for example, a congestion recovery control program, a communication control program, a data processing program and the like.

Therefore, the frame relay router 20 has the same structure as the frame relay terminal 3 of FIG.
The transmission throughput control device 4 includes a control code recognition processing unit 15 and a control code table 16. The control code table 16 is provided on the memory of the frame relay router 20.

The control code recognition processing unit 15 uses the control code table 16 to determine whether or not to perform the transmission throughput control by the non-congestion notification transmission throughput according to the frequency table 7 at the start of the communication session. Therefore, at the start of the communication session, the frame relay router 20 refers to the data in the predetermined position of the frame transmitted by itself, and recognizes the communication partner (destination port number or port address), Is used to refer to the control code table 16 to know the necessity of the transmission throughput control.

The port number is a number assigned to each port (port) of the plurality of communication processes operating on the data processing device 19. The port is a virtual port that is managed by an operating system (OS) on the data processing device 19 and has a one-to-one correspondence with a plurality of communication processes. The port number consists of 16 bits, for example. Data processing device 19
When communicating with a communication process on another data processing device 19, the above communication process specifies the partner process with which the user wants to communicate by describing the port number of the partner at a predetermined position of the transmission packet.

A well-known communication process has a reserved port number known as a well-known port. Therefore, by checking the port number described in the transmission packet, it is possible to know which communication process is currently performing communication.

As the upper application, for example, T
In CP / IP, there are "ftp-data", "ftp", etc. shown. If the higher-level application knows the control code,
It can be predetermined according to this. The control code is
It is set to "1" when the transmission throughput control based on the non-congestion notification transmission throughput is performed, and is set to "0" when the transmission throughput control based on the non-congestion notification transmission throughput is not performed. As shown in FIG. 11C, for example, when the upper application is “ftp-data”, the control code is “1” and the upper application is “teln
When it is "et", the control code is "0". The control code can be changed by the frame relay router 20 or the data processing device 19.

For example, when the upper application in TCP / IP is "telnet", the transmission of the frame is discontinuously performed with a certain time interval as shown in FIG. 13 (B). Become. Therefore, it is unlikely that this transmission will cause congestion in the frame relay network 1, and even if a temporary congestion occurs, it is considered that the congestion will disappear promptly due to the end of the intermittent transmission. In this case, the average value of the transmission throughput can be increased when the frame is transmitted with a high transmission throughput. Therefore, the control code recognition processing unit 15 determines not to perform the transmission throughput control based on the non-congestion notification transmission throughput defined by the frequency table 7 in order to transmit the frame with a high transmission throughput.

On the other hand, for example, when the upper application in TCP / IP is "ftp-data", the frames are continuously transmitted (the state of frame transmission is shown in FIG. 17B described later). Shown in). Therefore, since the transmission itself causes the congestion of the frame relay network 1, it is possible to receive the congestion notification. In this case, it is possible to increase the transmission throughput (average value) for a sufficiently long time by avoiding receiving the congestion notification by suppressing the transmission throughput to some extent. Therefore, the control code recognition processing unit 15
Frequency table 7 in order to suppress the transmission throughput.
It is decided to perform the transmission throughput control by the non-congestion notification transmission throughput determined by.

FIG. 13C shows the control code table 16
An example is shown. The control code table 16 stores the name and control code of the upper application corresponding to the port number used in communication.

FIG. 14 shows an example of a frame transmitted by the frame relay router 20 to the frame relay network 1. This frame is the frame relay terminal 3 of FIG.
Is also the frame to be sent by.

In the illustrated frame, flag is a bit string for recognizing the start and end of the frame of the frame relay, and is provided at the start and end of the frame. The address-field is information necessary for frame relay, and the FSC (CRC) is information for detecting a frame error.

In the address-field, DLCI is a data link identifier, which is divided into an upper part and a lower part.
C / R is a command / response indicator bit for identifying a command and response of a frame transmitted and received between the frame relay terminals 3, EA is an address field extension bit which is a spare bit for future extension, DE is a discardable frame indicator bit. The FECN bit and BECN bit for notification of congestion are
As shown in the figure, it is provided at a position following the lower part DLCI in the address-field and before the discardable frame display bit DE.

IP header and TCP header are IP and TC
DATA is a header of P, and DATA is data that the transmission source tries to send in this frame. In TCP header,
Source Port is the communication process above, Destination
Port is the above communication process, Sequence Number is the sequence number that indicates the position of the data stream that the sender tries to send, Acknowledgment Number is the acknowledgment number, and Hlen is the header that indicates the length of the TCP header. Long, Reserved is reserved for future expansion, Code bits are URG, ACK, PSH, RST, SYN,
It is a control flag consisting of 6 bits of FIN, and Wi
ndow is the acknowledgment number Acknowledge included in the TCP header
Checksum is information used to calculate the checksum, which is information indicating how long data can be received from the position indicated by the ledgement number.
nt Pointer is a pointer that is valid when the URG bit of the control flag Code bits is "1" and is a pointer indicating the storage location of emergency data, Option is an option area that is not normally used, and Padding is This is a fill-in area for making the length of the entire TCP header a multiple of 32 bits.

In the control flag Code bits, the URG bit "1" indicates that the data to be urgently processed is included. "1" of the ACK bit indicates that the response confirmation number is used. "1" of the PSH bit indicates that TCP passes the received data to the upper application. "1" of the RST bit indicates that the TCP virtual circuit is forcibly disconnected. The SYN bit “1” indicates that the sequence number is initialized. The FIN bit "1" indicates that the data sent by the sender has been completed.

FIG. 15 is a transmission mode identification processing flow. The frame relay router 20 receives the packet transmitted from the data processing device 19 (S31).

The control code recognition processing unit 15 reads the port address of the TCP header (S32), sequentially searches the control code table 16 using this port address, and obtains the corresponding control code (S33).

The control code recognition processing section 15 checks whether or not the obtained control code is "1" (S34). If the control code is not "1"("0"), the transmission throughput control by the transmission throughput management unit 5 is invalidated (S35).

When the control code is "1", the transmission throughput control by the transmission throughput management unit 5 is made effective (S36). As a result, the frame relay router 20
The sending throughput of is controlled as follows.

For example, when the upper application in TCP / IP is "telnet", the control code "0" invalidates the transmission throughput control by the transmission throughput management unit 5 in S35. Therefore, unlike the first embodiment, the sending throughput is not suppressed with the non-congestion notification sending throughput as the upper limit, and is updated even if the sending throughput exceeds the non-congestion notification sending throughput unless the congestion notification is received.

On the other hand, for example, when the upper application in TCP / IP is "ftp-data", the transmission throughput control by the transmission throughput management unit 5 is made effective in S36 by the control code "1". Therefore, similarly to the first embodiment, the transmission throughput is suppressed with the non-congestion notification transmission throughput as the upper limit for updating the transmission throughput.

(Third Embodiment) A third embodiment of the present invention will be described with reference to FIGS. This embodiment is also shown in FIG.
It corresponds to the first principle of the present invention shown in FIG. Also in this embodiment, the frame relay terminal 3 comprises the frame relay router 20. In this embodiment, the frame relay router 2
In this example, the transmission mode of the frame transmitted by 0 is recognized by the upper application and the transmission throughput is controlled based on this. To this end, the frame relay router 20 of this embodiment includes a higher application recognition processing unit 17 corresponding to the mode recognition processing unit 14 and a higher application table 18.

Therefore, in this embodiment, in place of the control code recognition processing unit 15 and the control code table 16 in the embodiment shown in FIG. 12, a higher application recognition processing unit 17 and a higher application table 18 are provided in the transmission throughput control device 4. This is an example provided, and other than these are the same as the embodiment shown in FIG. The upper application table 17 is provided in the memory of the frame relay router 3.

The upper application recognition processing section 17
The upper application table 18 is used to determine whether or not to perform the transmission throughput control based on the non-congestion notification transmission throughput according to the frequency table 7. For this,
The frame relay router 20 recognizes the communication partner and its upper application by referring to the data in a predetermined position of the frame transmitted by itself, and uses this to refer to the upper application table 18 to refer to the transmission throughput control. Know if you need it.

[0157] For example, when the upper application in TCP / IP is "ftp-data", as shown in Fig. 17 (B), the frames are continuously transmitted. Therefore, since the transmission itself causes the congestion of the frame relay network 1, it is possible to receive the congestion notification. In this case, it is possible to increase the transmission throughput (average value) for a sufficiently long time by avoiding receiving the congestion notification by suppressing the transmission throughput to some extent. Therefore, the upper application recognition processing unit 17 determines to perform the transmission throughput control based on the non-congestion notification transmission throughput determined by the frequency table 7 in order to suppress the transmission throughput.

On the other hand, for example, when the upper application in TCP / IP is "telnet", the transmission of the frame is discontinuous at certain time intervals as shown in FIG. 13B. Will be done. Therefore, as described above, in this case, the upper application recognition processing unit 17 does not perform the transmission throughput control by the non-congestion notification transmission throughput defined by the frequency table 7 in order to transmit the frame with a high transmission throughput. Decide that.

FIG. 17C shows an example of the upper application table 18. The upper application table 18 stores the name of the upper application corresponding to the port number used in communication. As described above, the port number can be known in advance (reserved), and the host application is determined from the port number. As the upper application, for example, TCP / I
There is “ftp-data” and the like shown in P.

Data transfer by "ftp-data", which is a higher-level application involving continuous data transfer, is performed as follows. As shown in FIG. 17 (A), when data is transferred between two data processing devices 19, the upper application "ftp" establishes a control connection between the data processing devices 19 to perform interactive communication. . Further, when the upper application “ftp-data” performs data transfer, it establishes a data transfer connection between the data processing devices 19 and transfers the data.

In such data transfer, the packet flowing in the data transfer connection can be identified by referring to the port address of the TCP header. Further, before the actual data transfer by the data transfer connection, in the interactive communication by the control connection, the size of the data to be sent is written at a predetermined position of the data in the packet.

Therefore, the upper application recognition processing section 17 of the frame relay router 20 uses the TCP of the packet.
Find out which port the packet uses by looking up the port address in the header. Then, the higher-level application recognition processing section 17 refers to the higher-level application table 18 by using the obtained port address and knows what the corresponding higher-level application is.

When the upper application is "ftp-data" for continuous data transmission, the upper application recognition processing unit 17 determines the size of the data (transfer data size) written in a predetermined position of the data portion in the packet of the control connection. ) Is read. Then, the higher-level application recognition processing unit 17 checks whether the read transfer data size is equal to or larger than a predetermined data size (threshold value) that is set in advance. For this reason, the threshold value can be empirically determined, and the upper application recognition processing unit 1
Given to 7.

When the transfer data size is equal to or larger than the threshold value, there is a possibility that the amount of data transmission is considerably large and the notification of congestion is received. Therefore, in this case, the upper application recognition processing unit 17 performs the transmission throughput control by the non-congestion notification transmission throughput, that is,
It decides to validate the transmission throughput control and notifies the transmission throughput management unit 15. On the other hand, when the transfer data size is not larger than the threshold value, the data transmission amount is not so large and it is expected that the congestion notification will not be caused. Therefore, in this case, the upper application recognition processing unit 17 determines not to perform the transmission throughput control by the non-congestion notification transmission throughput, that is, disables the transmission throughput control, and notifies the transmission throughput management unit 15.

FIG. 18 is a higher application identification processing flow. The frame relay router 20 receives the packet transmitted from the data processing device 19 (S41).

The upper application recognition processing section 17
Read the port address of the TCP header (S42),
Using this port address, the upper application table 17 is sequentially searched to find the corresponding upper application, and it is checked whether this is "ftp-data" (S4).
3). When it is not "ftp-data", S41 and subsequent steps are repeated.

If it is "ftp-data", the upper application recognition processing section 17 monitors the data section in the packet of the ftp connection to be transmitted next, and reads the transfer data size (S44).

Next, the upper application recognition processing section 1
It is checked whether the transfer data size read by 7 is equal to or larger than the threshold value (S45). If it is not more than the threshold value, the upper application recognition processing unit 17 invalidates the maximum transmission throughput control by the transmission throughput management unit 5 (S4).
6).

If it is equal to or more than the threshold value, the upper application recognition processing section 17 validates the maximum transmission throughput control by the transmission throughput management section 5 (S47). As a result, the transmission throughput of the frame relay router 20 is controlled as follows.

For example, when the upper application in TCP / IP is "ftp-data", this is recognized in S43, and if the transfer data size is equal to or larger than the threshold value,
The transmission throughput control by the transmission throughput management unit 5 is validated. Therefore, when the transfer data size is equal to or larger than the threshold value, the sending throughput is suppressed with the non-congestion notification sending throughput as the upper limit for updating the sending throughput, as in the first embodiment. On the contrary, when the transfer data size is less than or equal to the threshold value, unlike the first embodiment, the sending throughput is not suppressed with the non-congestion notification sending throughput as the upper limit, and the sending throughput exceeds the non-congestion notification sending throughput. Is updated in stages unless a congestion notification is received.

On the other hand, for example, when the upper application in TCP / IP is "telnet", it is recognized in S43 that the upper application is not "ftp-data", and the transmission throughput control by the transmission throughput management unit 5 is invalidated. It Therefore, unlike the first embodiment, the transmission throughput is not suppressed with the non-congestion notification transmission throughput as the upper limit, and is updated in stages unless the congestion notification is received even if the transmission throughput exceeds the non-congestion notification transmission throughput. To be done.

(Fourth Embodiment) A fourth embodiment of the present invention will be described with reference to FIGS. 19 and 20. This embodiment is shown in FIG.
It corresponds to the second principle of the present invention shown in FIG. That is, this is an example in which the transmission throughput is dynamically changed in relation to the congestion notification.
The frame relay terminal 3 of this embodiment is the first one shown in FIG.
It is connected to the frame relay network 1 via the line 2 similarly to the frame relay terminal 3 of the embodiment, but the control of the transmission throughput dynamically and promptly changes the transmission throughput according to the state of the frame relay network 1. Done by
When the congestion notification is received from the frame relay network 1, the congestion recovery control is performed. The frame relay terminal 3 of this embodiment does not include a processing unit corresponding to the mode recognition processing unit 14 of FIG.

FIG. 19 is a block diagram of the embodiment, and shows a frame relay terminal 3, its transmission throughput control device 4, and a communication system for performing communication in the frame relay format. As shown in FIG. 19, the frame relay terminal 3 includes a transmission throughput control device 4, a communication control unit 10, and a data processing unit 1.
3 and 3. This is the same as the frame relay terminal 3 of the first embodiment shown in FIG.

The communication control section 10 is provided with a clock generation circuit 26 which supplies a clock for transmission and reception to the frame transmission section 11 and the frame reception section 12. Clock generation circuit 2
6 is also provided in the first to third embodiments, the illustration of which is omitted. The clock supplied by the clock generation circuit 26 has a cycle determined by the line 2. That is, the transmission speed e of the line 2 can be known by examining the clock supplied by the clock generation circuit 26.

The frame transmission throughput in the frame transmission unit 11 is a value determined by the transmission throughput management unit 5 (throughput determination unit 31). The frame transmission unit 11 sends each frame data to the line 2 in synchronization with the clock supplied from the clock generation circuit 26. The frame receiving unit 12 receives the frame transmitted from the frame relay network 1 in synchronization with the clock supplied from the clock generating circuit 26.

The transmission throughput control device 4 controls the transmission throughput of frames in the frame transmission section 11. To this end, the transmission throughput control device 4 includes a transmission throughput management unit 5 and a congestion notification monitoring unit 9. The transmission throughput management unit 5 includes a dynamic determination processing unit 25 and a received frame number counting unit 27. Congestion notification monitoring unit 9
Notifies the transmission throughput managing unit 5 of the monitoring result of the frame receiving unit 12.

The received frame number counting unit 27 counts the number of received backward frames when the frame receiving unit 12 receives the backward frames and is not a congestion notification. In addition, the count processing of the number of received frames is performed by the frequency update processing unit 6 in the first to third embodiments.
Is a process performed by.

When the count value exceeds the predetermined value n, the received frame number counting section 27 notifies the dynamic decision processing section 25 to that effect. At this time, the count value is reset to 0. Here, n is a predetermined value,
Experientially determined. The value n is given to the received frame number counting unit 27 in advance as a transmission throughput control program. The value of n is set to a relatively small value so that the maximum value of the transmission throughput can be dynamically changed in a sufficiently short time interval. This makes it possible to shorten the time interval for updating the maximum value of the transmission throughput and dynamically update the maximum value of the transmission throughput.

The dynamic determination processing section 25 uses the reduction range calculation section 3
0, a throughput determination unit 31, an increase amount calculation unit 32, and a speed recognition device 35. The throughput determining unit 31 includes a current value holding unit 33. The coefficient table 34 is managed by the increment calculation unit 32, and is provided in the memory of the frame relay terminal 3.

The dynamic decision processing unit 25 dynamically updates (increases) the maximum value of the transmission throughput based on the state of the frame relay network 1, that is, the reception result of the congestion notification in the frame receiving unit 12. The frame transmission unit 11 is made to transmit the frame with the updated value. Further, when the frame receiving unit 12 receives the congestion notification, the dynamic determination processing unit 25 performs the congestion recovery control. Dynamic decision processing unit 25
Monitors the reception of the congestion notification in the frame reception unit 12, determines that the maximum value of the transmission throughput is lowered to a predetermined value in response to the reception, and sends the frame transmission with this value to the frame transmission unit 11. The congestion recovery control.

First, the transmission throughput control performed by the dynamic decision processing unit 25 will be described. The increase amount calculation unit 32
When receiving a notification from the received frame number counting unit 27 that the backward frame received number count value is equal to or greater than the predetermined value n, a predetermined calculation is performed to increase the maximum value (increase amount) of the transmission throughput. determine up. Here, it is calculated as up = f (e). That is, the increment u
p is a function of the transmission rate e of the line 2. Transmission speed e
Is predetermined depending on which frame relay network 1 the frame relay terminal 3 is connected to. The increase width up of the maximum value of the transmission throughput is dynamically changed in consideration of the transmission rate e of the line 2.

Prior to the start of communication, the speed recognizing device 35 determines the cycle of the clock generated by the clock generating circuit 26, and from this the transmission speed e of the line 2. The obtained transmission rate e is maintained by the rate recognition device 3 until the end of the communication.
5 or the increase amount calculation unit 32 holds.

The function f (e) is a function represented by f (e) = c × e + d. Here, the values stored in the coefficient table 34 are used as the coefficients c and d. The coefficients c and d are linear functions of the time elapsed since the start of transmission (transmission elapsed time), and in particular, the coefficient c is set to have a negative coefficient (inverse proportion) with respect to the transmission elapsed time. To be done.
Therefore, since the coefficient c (and d) has a large value at the start of transmission, the value of the function f (e) also increases, and the value of the coefficient c (and d) decreases with the elapse of time.
The value of (e) also becomes small. The coefficient table 34 stores the values of the coefficients c and d for each transmission elapsed time.

The coefficients c and d may be values determined according to, for example, the time that has elapsed since the start of transmission (transmission elapsed time) and the number of times of processing for increasing the transmission throughput. Therefore, the coefficient table 34 in this case has, for example, entry of the transmission elapsed time in the horizontal direction, entry of the number of rising processes in the vertical direction, and the values of the coefficients c and d stored at the intersections of the entries. The coefficients c and d are set so as to have a negative coefficient (inverse proportion) with respect to both the transmission elapsed time and the number of rising processes. That is, in the entries having the same transmission elapsed time, the values of the coefficients c and d are reduced as the number of times of ascending processing increases. Further, in the entries having the same number of rising processes, the values of the coefficients c and d are reduced as the transmission elapsed time increases. Therefore, at the start of transmission, the values of the coefficients c and d are large, so the value of the function f (e) is also large, and the values of the coefficients c and d are small over time, so the value of the function f (e) is small. Become. Further, the smaller the number of times of ascending processing is, the larger the values of the coefficients c and d are, so that the value of the function f (e) is also large. The value also becomes smaller. In this case, the number of rising processes is reset to 0 in response to the congestion notification and the process of reducing the maximum value of the transmission throughput (described later), for example.

The dynamic determination processing section 25 has a timer, and monitors the frame transmission section 11 using this. That is, the timer is started when the frame transmitter 11 starts the transmission, and reset when the transmission is completed. The increment calculation unit 32 refers to this timer to obtain its value, uses this timer value to refer to the coefficient table 34, and obtains the values of the coefficients c and d at that time. Further, the increase amount calculation unit 32 obtains the value of the function f (e) using the values of the coefficients c and d, and sends it to the throughput determination unit 31. Further, if necessary, the dynamic determination processing unit 25 may be provided with a counter for the number of times of increase processing of the transmission throughput.

It should be noted that the coefficients c and d may be calculated by the increment calculation section 32 without providing the coefficient table 34. Further, when performing more complicated control of the increase rate of the transmission throughput, the coefficients c and d may be set to be a higher-order function of the transmission time.

When the throughput determination unit 31 receives the increase amount up from the increase amount calculation unit 32, the throughput determination unit 31 updates it so as to increase the maximum value of the transmission throughput. That is, the throughput determination unit 31 reads the maximum value of the current transmission throughput from the current value holding unit 33, adds the increase width up to the read value, obtains a new maximum value of the transmission throughput, and transmits the frame. Send to department 11.
As a result, the frame transmission unit 11 transmits the frame at the new maximum value of the transmission throughput increased by the increase amount up from the value of the transmission throughput up to that point. The new maximum value of the transmission throughput is stored in the current value storage unit 33 instead of the value up to that point.

As a result, the sending throughput is gradually updated to a large value unless the congestion notification is received.
That is, the transmission throughput is "0 kbp" before the start of transmission.
The value gradually increases from "s", exceeds the CIR at a certain point, further increases gradually, and finally reaches the physical line speed (transmission speed e) of the line 2. In this process, the range of increase in the transmission throughput depends on the transmission rate e of the line 2, the transmission elapsed time,
It is dynamically changed based on the number of rising processes.

Next, the congestion recovery control executed by the dynamic decision processing unit 25 when the congestion notification is received will be described.
The congestion notification may be received at some point in the process in which the dynamic determination processing unit 25 performs the transmission throughput control as described above. As described above, the congestion notification monitoring unit 9 monitors the frame reception unit 12, and when the congestion notification is received, notifies the decrease amount calculation unit 30 of the dynamic determination processing unit 25 of this.

When the congestion reduction monitor 30 receives the congestion notification from the congestion notification monitor 9, the reduction calculation unit 30 performs a predetermined calculation to reduce the maximum amount of the transmission throughput (reduction amount) do.
Determine wn. Here, it is calculated as down = g (CIR). That is, the reduction amount down is a function of CIR.

The function g (CIR) is g (CIR) = a × C
This is a function represented by IR + b. Where the coefficients a and b
Is a coefficient of a predetermined value and is empirically determined. The coefficients a and b are given to the reduction amount calculation unit 30 in advance as a transmission throughput control program. Reduction amount calculation unit 30
Calculates the value of the function g (CIR) using the CIR value,
This is sent to the throughput determination unit 31.

It should be noted that the coefficients a and b are set to relatively large values so that the reduction amount down has a sufficiently large value for congestion recovery. Therefore, for example, the decrease width down is the increase width up
Is set to a value (absolute value) larger than the maximum value of. Further, the coefficients a and b are different from those used to obtain the reduction amount y in S4 of FIG.

When the throughput reduction unit 31 receives the reduction amount down from the reduction amount calculation unit 30, the throughput determination unit 31 updates the maximum value of the transmission throughput so as to decrease it. That is, the throughput determination unit 31 reads the maximum value of the current transmission throughput from the current value holding unit 33, subtracts the reduction amount down from the read value, and obtains a new maximum value of the transmission throughput, Transmitter 11
Send to. As a result, the frame transmission unit 11 transmits the frame at the new maximum value of the transmission throughput that is reduced by the reduction amount down from the value of the transmission throughput up to that point. The new maximum value of the transmission throughput is stored in the current value storage unit 33 instead of the value up to that point.

As a result of the above, the transmission throughput is updated to a small value sufficient for congestion recovery. As a result, the transmission throughput of the frame relay terminal 3 is reduced,
Since the number of frames to be sent is suppressed, the congestion of the frame relay network 1 can be recovered.

Therefore, while performing such congestion recovery control, the value of the sending throughput can be dynamically and promptly increased as long as the congestion notification is not received, and the average value of the sending throughput can be improved.

FIG. 20 is a transmission throughput management (and congestion recovery control) processing flow. The frame receiving unit 12 receives the frame transmitted from the frame relay network 1 (S61).

Whether or not the congestion notification monitor 9 is a congestion notification, that is, the BECN bit of the frame is "1 (ON)".
Is checked (S62). If it is ON, the reduction amount calculation unit 30 determines the reduction amount d of the maximum value of the transmission throughput.
"own" is obtained by a predetermined calculation (S63).

The throughput determining unit 31 determines that the reduction width dow
A new maximum value of the transmission throughput is obtained from n and the current value of the maximum value of the transmission throughput read from the current value holding unit 33 (S64). The maximum value of this transmission throughput is a value smaller than the value up to that time by the amount of the down width, in order to recover the congestion.

Upon receiving the notification from the throughput determining unit 31, the frame transmitting unit 11 transmits the frame to the frame relay network 1 with a new transmission throughput (S65). Less than,
The steps from S61 onward are repeated.

On the other hand, in S62, the BECN of the frame
If the bit is not ON (OFF), the received frame number counting unit 27 adds “+1” to the number of consecutive receptions of frames (the number of consecutive receptions) up to that point to obtain a new received frame count value (continuous The number of times of reception is recorded (S66). For this purpose, the received frame number counting unit 27 includes, for example, a counter.

Next, the reception frame number counting section 27 checks whether or not the count value of the reception frame number is larger than a predetermined value n (S67). If not, the following S6
8, S69 and S65 are omitted and S61 and subsequent steps are repeated.

If it is larger, the increase amount calculating section 32 obtains the increase amount up of the maximum value of the transmission throughput by a predetermined calculation (S68). At this time, the speed recognition device 35 obtains the transmission speed e of the line 2 in advance before starting the communication. In addition, the coefficient table 34
Is referred to and the coefficients c and d are obtained.

The throughput determining unit 31 obtains a new maximum value of the transmission throughput from the increase amount up and the current value of the maximum value of the transmission throughput read from the current value holding unit 33 (S69). The maximum value of the transmission throughput is a value larger than the value up to that point by the increase amount up in order to improve the average value of the transmission throughput.

Upon receiving the notification from the throughput determination unit 31, the frame transmission unit 11 transmits the frame to the frame relay network 1 with a new transmission throughput (S65). Less than,
The steps from S61 onward are repeated.

The frame relay terminal 3 changes its transmission throughput as follows by the above transmission throughput control and congestion recovery control. Unless the frame relay terminal 3 receives the congestion notification in S61, the frame relay terminal 3 increases the transmission throughput by the continuous reception of (n + 1) frames by the transmission throughput control. The value of n is made relatively small, and the increase width up of the transmission throughput is changed according to the transmission time. Furthermore, the transmission rate e of the line 2 is taken into consideration in the determination of the increase width up. As a result, the maximum value of the transmission throughput can be dynamically updated according to the state of the line 2.

It is assumed that the frame relay terminal 3 receives the congestion notification in S61 when the transmission throughput reaches a high value. As a result, the transmission throughput is lowered to a considerably low value in S63 to S65. That is,
Congestion recovery control is performed by suppressing the transmission throughput.

As a result, the frame relay terminal 3 detects the S6
As long as the congestion notification is not received at 1, the transmission throughput is rapidly increased at short time intervals. Therefore, it is possible to transmit a frame with a high transmission throughput, and it is possible to improve the average value of the transmission throughput. Further, when the congestion notification is received in S61, the value of the transmission throughput can be immediately reduced to perform the congestion recovery control.

(Fifth Embodiment) A fifth embodiment of the present invention will be described with reference to FIGS. 21 to 24. This embodiment is also shown in FIG.
It corresponds to the second principle of the present invention shown in FIG. In this embodiment, the frame relay terminal 3 comprises a frame relay router 20 as in the second and third embodiments. This embodiment is an example of recognizing a transmission mode of a frame transmitted by the frame relay router 20 by a host application and controlling the transmission throughput based on this.
For this reason, the frame relay router 20 of the present embodiment is
Upper application recognition processing unit 36 and upper application table 37 corresponding to the mode recognition processing unit 14
Equipped with.

FIG. 21 is a block diagram of the embodiment, showing a frame relay router 20, its transmission throughput control device 4, and a communication system for performing communication in the frame relay format. The communication of this embodiment is similar to the second and third embodiments in that the communication between the two data processing devices 19 is
Source data processing device 19 and frame relay router 2
Communication with the frame relay router 20 is performed in the packet format according to TCP / IP, communication with the frame relay router 20 is performed in the frame relay format via the frame relay network 1, and data between the frame relay router 20 and the receiving side is transmitted. Communication with the processing device 19 is performed in a packet format according to TCP / IP, for example. Therefore, the frame relay router 20
The frame sent by the frame relay network 1 is the same as the frame shown in FIG.

The frame relay router 20 performs transmission throughput control and congestion recovery control in the same manner as the frame relay terminal 3 described above when transmitting a frame to the frame relay network 1. The frame relay router 20 has the same configuration as the frame relay terminal 3 of FIG. 19, and further includes a higher application recognition processing unit 36 and a higher application table 37. The upper application table 37 is provided on the memory of the frame relay router 20.

FIG. 22 shows an example of the upper application table 37. Upper application table 37
Stores the name of the upper application in TCP / IP, the control code, and the number of times of frame reception (reference value) corresponding to the port number. As described above, the port number can be known in advance (reserved), and the host application is determined from the port number.

The control code is data for instructing whether or not the transmission throughput control of this embodiment is valid. In this embodiment, the control code of "ftp" and "telnet", which was set to "0" in the second and third embodiments, may be set to "1" as shown in the figure, and the good transmission throughput control and Congestion recovery control can be performed.

The number of frame receptions (reference value) n'is data (time interval parameter) that determines the time interval for performing the transmission throughput control, that is, the interval for performing the update (increasing) process of the maximum value of the transmission throughput. When the count value of the number of received frames in the received frame number counting unit 27 is larger than the number of frame receptions (reference value) n ′, the process of increasing the maximum value of the transmission throughput is performed. As a result, the time interval of the process of increasing the maximum value of the transmission throughput is dynamically changed according to the type of higher-rank application.

For example, if the upper application is "telne
If it is "t", the frame is transmitted discontinuously at certain time intervals (see FIG. 13B). Therefore, it is unlikely that this transmission will cause congestion, and even if a temporary congestion occurs, it is considered that the congestion will disappear promptly due to the end of the intermittent transmission. In this case, the average value of the transmission throughput can be increased when the frame is transmitted with a high transmission throughput. Therefore, the number of frame receptions (reference value) is a small value of "2". As a result, even when the transmission throughput control is performed with the control code set to "1", the transmission throughput is immediately increased when the number of frame receptions exceeds "2". That is, the transmission throughput increases frequently, and frames can be transmitted with high transmission throughput.

On the other hand, for example, if the upper application is "ft
In the case of “p-data”, the frame is continuously transmitted (see FIG. 17B). Therefore, since the transmission itself causes congestion, it is possible to receive a congestion notification. In this case, it is possible to increase the transmission throughput (average value) for a sufficiently long time by avoiding receiving the congestion notification by suppressing the transmission throughput to some extent. Therefore, the number of frame receptions (reference value) is set to a large value of "10". This prevents the transmission throughput from being increased until the number of frame receptions exceeds "10". That is, the transmission throughput gradually increases, and it is possible to avoid receiving the congestion notification.

The upper application recognition processing section 36
Similar to the second embodiment, the upper application table 3
At the beginning of the communication session using the control code of 7,
Determines whether or not to perform transmission throughput control. For this reason, the frame relay router 20 recognizes the other party of communication and its upper application in the same manner as in the second and third embodiments, refers to the upper application table 37 using this, and determines whether it is necessary to control the transmission throughput. To know

This processing is performed in the same manner as the transmission mode identification processing flow shown in FIG. Therefore, for example, when the upper application is “telnet” and the control code is “0”, the transmission throughput control is invalid. In this case, the transmission throughput is updated without being suppressed unless the congestion notification is received. On the other hand, for example, when the upper application is “ftp-data”, the transmission throughput control is enabled by the control code “1”. In this case, the transmission throughput control according to this embodiment is executed. In this embodiment, the control code may be "1" even if the upper application is "telnet".

The upper application recognition processing unit 3
No. 6 is the number of frame receptions (reference value) of the upper application table 37 when the control code is "1"
n ′ is used to dynamically change the time interval for updating the maximum value of the transmission throughput. That is, in this embodiment, not only the increase width up of the maximum value of the transmission throughput but also the time interval of the increase processing is dynamically changed according to the type of the upper application. As a result, the increase width u
It is possible to further dynamically change the maximum value of the transmission throughput according to the state of the frame relay network 1 and the type of communication, as compared with the case where only p is changed dynamically, and to improve the average value of the transmission throughput. You can

For this reason, when the control code is "1", the upper application recognition processing section 36 reads the frame reception number (reference value) n'from the upper application table 37, and the received frame number counting section 2
Notify 7. The reception frame number counting unit 27 substitutes this value n ′ for a predetermined value n. Therefore, the received frame number counting unit 27 notifies the dynamic determination processing unit 25 when the count value becomes equal to or larger than the predetermined value n ′.
As a result, the threshold value of the count value is dynamically changed.

The higher application recognition processing section 3
When the control code is "0", 6 indicates that the number of received frames (reference value) n'is infinity (actually, a value larger than the maximum count value of the received frame number counting unit). Notify 27. The received frame number counting unit 27 sets the predetermined value n to infinity. As a result, the count value in the received frame number counting unit 27 does not exceed the predetermined value n. Therefore, the process of increasing the maximum value of the transmission throughput according to the present embodiment is not performed. That is, the transmission throughput control can be invalidated.

Here, the upper application recognition processing section 36 and the upper application table 37 have been described as constituting the mode recognition processing section 14, but they may have the following configurations. That is, the upper application recognition processing unit 36 is divided into a higher application detection unit and a recovery width changing unit. The upper application detection unit
Among the above-mentioned various processes performed by the higher-level application recognition processing unit 36, only the higher-level application recognition process is performed. This constitutes the mode recognition processing unit 14. The recovery width changing unit performs the process of increasing the maximum value of the transmission throughput, that is, the above-described various processes performed by the upper application recognition processing unit 36 other than the above. The upper application table 37 is managed by the recovery width changing unit.
The recovery width changing unit constitutes a part of the dynamic determination processing unit 25 together with the upper application table 37.

FIG. 23 is a transmission throughput management (and congestion recovery control) processing flow. The frame receiving unit 12 receives the frame transmitted from the frame relay network 1 (S71).

Whether or not the congestion notification monitor 9 is a congestion notification, that is, the BECN bit of the frame is "1 (ON)".
Is checked (S72). If it is ON, the reduction amount calculation unit 30 determines the reduction amount d of the maximum value of the transmission throughput.
"own" is obtained by a predetermined calculation (S73).

The throughput determining unit 31 determines that the reduction width dow
A new maximum value of the transmission throughput is obtained from n and the current value of the maximum value of the transmission throughput read from the current value holding unit 33 (S74). The maximum value of this transmission throughput is a value smaller than the value up to that time by the amount of the down width, in order to recover the congestion.

Upon receiving the notification from the throughput determining unit 31, the frame transmitting unit 11 transmits the frame to the frame relay network 1 with a new transmission throughput (S75). Less than,
The steps from S71 onward are repeated.

On the other hand, the BECN of the frame in S72
If the bit is not ON (OFF), the received frame number counting unit 27 adds “+1” to the number of consecutive receptions of frames (the number of consecutive receptions) up to that point to obtain a new received frame count value (continuous The number of times of reception is recorded (S76).

The upper application recognition processing unit 36 recognizes the upper application from the transmission frame in the frame transmission unit 11 (S77). That is, the upper application recognition processing unit 36 obtains the control code from the upper application table 37 in the same manner as the processing shown in FIG.

When the control code is "1", the upper application recognition processing section 36 reads the frame reception number (reference value) n'from the upper application table 37 and notifies the received frame number counting section 27. The received frame number counting unit 27 substitutes this value n'for a predetermined value n (S78).

When the control code is "0", the upper application recognition processing unit 36 counts the number of received frames as infinity (a value larger than the maximum count value of the received frame number counting unit) as the number of frame receptions (reference value). Notify the unit 27. The received frame number counting unit 27 sets the predetermined value n to infinity.

The reception frame number counting section 27 checks whether or not the count value of the reception frame number is larger than a predetermined value n (S79). If not larger, S80 and S8 below
1 and S75 are omitted, and S71 and subsequent steps are repeated. When the control code is "0", the count value does not exceed the predetermined value n.

If it is larger, the increase amount calculation section 32 obtains the increase amount up of the maximum value of the transmission throughput by a predetermined calculation (S80). At this time, the speed recognition device 35 obtains the transmission speed e of the line 2 in advance before starting the communication. In addition, the coefficient table 34 is based on the transmission elapsed time and the like.
Is referred to and the coefficients c and d are obtained.

The throughput determining unit 31 obtains a new maximum value of the transmission throughput from the increase amount up and the current maximum value of the transmission throughput read from the current value holding unit 33 (S81). The maximum value of the transmission throughput is a value larger than the value up to that point by the increase amount up in order to improve the average value of the transmission throughput.

Upon receiving the notification from the throughput determining unit 31, the frame transmitting unit 11 transmits the frame to the frame relay network 1 with a new transmission throughput (S75). Less than,
The steps from S71 onward are repeated.

FIG. 24 shows the transmission throughput control. The frame relay terminal 3 changes its transmission throughput as shown in FIG. 24 by the above transmission throughput control and congestion recovery control.

Similar to the second and third embodiments, the upper application recognition processing section 36 knows what the upper application is by referring to the port address of the TCP header of the packet. As a result, the number of frame receptions (reference value) n ′, that is, n is determined.

As shown by the solid line in FIG. 24A, the frame relay terminal 3 starts frame transmission and gradually increases the transmission throughput. In this case, both the time interval of increase processing of the transmission throughput and the increase width up are dynamically determined. That is, the frame relay terminal 3 of the present embodiment, unless receiving the congestion notification, at a time interval determined by continuous reception of (n + 1) frames, which is a value according to the upper application, depending on the transmission start time and the number of rising processes. The transmission throughput is increased by the determined increase width up.

If this value of n is set to a predetermined value, it will be the same as in the fourth embodiment. In this case, as described above, the value of n is made relatively small so that the transmission throughput can be quickly increased.

Here, for example, if the upper application is "telnet", n has a small value of "2". Therefore, as shown in FIG. 24A, the transmission throughput is frequently increased. As a result, in the case of communication that will not cause congestion, it is possible to dynamically increase the transmission throughput and increase the average value. On the other hand, for example, if the upper application is “ftp-data”, n has a large value of “10”. Therefore, as shown in FIG. 24 (B), the transmission throughput is gradually increased. As a result, in the case of communication that may cause congestion, the average throughput can be increased by gradually increasing the transmission throughput so that the congestion notification is not received.

[0239] Time T when the transmission throughput becomes a high value
It is assumed that the frame relay terminal 3 receives the congestion notification at 3 and T4. As a result, the transmission throughput is reduced by do.
It is dropped to a value as low as wn. That is, the congestion recovery control is performed while suppressing the transmission throughput. After that, the frame relay terminal 3 increases the transmission throughput by the increase width up at the time interval in the same manner as described above.

Since the reduction width is down = g (CIR), the value of the transmission throughput may be equal to or lower than the CIR when the congestion notification is received at the time when the transmission throughput is not so high. In this case, the new value of the transmission throughput may be the CIR instead of the value below the CIR.

As described above, the frame relay terminal dynamically changes its transmission throughput, in particular, the increase range of the transmission throughput and the time interval of the increase processing according to the elements related to the congestion notification. Therefore, it is possible to dynamically change the transmission throughput in response to traffic fluctuations and improve the average value. Further, when the congestion notification is received, the value of the transmission throughput can be immediately reduced to perform the congestion recovery control.

The present invention has been described above with reference to the embodiments.
The present invention is not limited to the above embodiments, but can be variously modified within the scope of the spirit thereof. For example, when the congestion notification is received, the transmission throughput may be reduced to the CIR without being reduced to the new non-congestion notification transmission throughput. Further, the new non-congestion notification transmission throughput may be compared with the CIR and the value may be decreased to the larger value. Further, the coefficients a to d for obtaining the increase width up and the decrease width down may be determined depending on other elements related to the congestion notification.
Further, the increase width up and the decrease width down themselves may be determined by other methods or depending on other factors related to congestion notification.

Further, the above-mentioned respective embodiments may be combined and implemented. In particular, any of the embodiments according to the first principle and any of the embodiments according to the second principle may be combined and implemented. In this case, it is desirable to control the transmission throughput according to the first principle in the time zone where the traffic fluctuation is gentle and to control the transmission throughput according to the second principle in the time zone where the traffic fluctuation is severe. Whether the transmission throughput control is based on the first or second principle is determined by, for example, empirically obtaining a time zone during which a large amount of communication traffic is present in a day, and instructing the transmission throughput control program in advance, or by an operator input. Therefore, it may be switched from the outside.

Further, the present invention is not limited to the frame relay terminal and its control device and communication system, but can be widely applied to the terminal for performing congestion recovery control, its control device and communication system.

[0245]

As described above, according to the present invention,
In a frame relay terminal for performing congestion recovery control, a control device therefor, and a communication system using the same, the transmission throughput is controlled with an upper limit of the non-congestion notification transmission throughput determined according to the reception frequency of congestion notification for each transmission throughput size. By doing so, the probability of receiving a congestion notification can be made extremely small, so the optimal value for the transmission throughput, that is, the maximum value in the range in which it can be predicted with certainty that the congestion notification will not be received (non-congestion notification transmission) Throughput), and the number of times the control to suddenly decrease the sending throughput due to the reception of the congestion notification is performed can be extremely reduced.Furthermore, the number of frame retransmissions can be extremely reduced, and the average of the sending throughput can be set. The value can be improved.

Further, according to the present invention, in a frame relay terminal for performing congestion recovery control, its control device, and a communication system using the same, the increment of update of the maximum value of the transmission throughput and the update time interval are dynamically set. By controlling and controlling to reduce the transmission throughput according to the CIR when receiving the congestion notification, the transmission is performed following the factors that cause congestion such as the line status, communication status, and communication type. Throughput can be changed dynamically and promptly, and as a result, the number of times of receiving congestion notification can be reduced while keeping the sending throughput relatively large, so that the average value of the sending throughput can be improved. it can.

[Brief description of drawings]

FIG. 1 is a first principle configuration diagram of the present invention.

FIG. 2 is a second principle configuration diagram of the present invention.

FIG. 3 is a first operation explanatory view of the present invention.

FIG. 4 is a second operation explanatory view of the present invention.

FIG. 5 is a configuration diagram of an embodiment.

FIG. 6 is an explanatory diagram of an example.

FIG. 7 is an explanatory diagram of an example.

FIG. 8 is an explanatory diagram of an example.

FIG. 9 is an explanatory diagram of an example.

FIG. 10 is a frequency update processing flow.

FIG. 11 is a transmission throughput management processing flow.

FIG. 12 is a configuration diagram of an embodiment.

FIG. 13 is an explanatory diagram of an example.

FIG. 14 is an explanatory diagram of an example.

FIG. 15 is a transmission mode identification processing flow.

FIG. 16 is a configuration diagram of an embodiment.

FIG. 17 is an explanatory diagram of an example.

FIG. 18 is a higher application identification processing flow.

FIG. 19 is a configuration diagram of an embodiment.

FIG. 20 is a transmission throughput management processing flow.

FIG. 21 is a configuration diagram of an embodiment.

FIG. 22 is an explanatory diagram of an example.

FIG. 23 is a transmission throughput management processing flow.

FIG. 24 is an explanatory diagram of an example.

FIG. 25 is a diagram illustrating a conventional technique.

[Explanation of symbols]

1 frame relay network 2 physical lines 3 frame relay terminals 4 Transmission throughput control device 5 Transmission throughput management unit 6 Frequency update processing unit 7 Frequency table 8 Transmission throughput measurement unit 9 Congestion notification monitoring unit 10 Communication control unit 11 frame transmitter 12 frame receiver 13 Data processing unit 14 Mode recognition processing unit 15 Control code recognition processing unit 16 Control code table 17 Upper application recognition processing unit 18 Upper application table 19 Data processing device 20 frame relay router 25 Dynamic decision processor 26 Clock generation circuit 27 Received frame number counting unit 30 Decrease calculation part 31 Throughput determination unit 32 Raising amount calculation section 33 Current value storage 34 coefficient table 35 Speed recognition device

Claims (17)

(57) [Claims] 1. A frame relay terminal which is connected to a frame relay network and which transmits and receives frames to and from the frame relay network, and a transmission throughput measuring unit for monitoring a frame transmission throughput to the frame relay network, and the frame relay network. Congestion notification monitoring unit for monitoring the reception of congestion notification from, the frequency table accumulating the results of monitoring in the transmission throughput measuring unit and congestion notification monitoring unit, the result of monitoring in the transmission throughput measuring unit and congestion notification monitoring unit The frequency table is created based on the above, the maximum value of the transmission throughput of the frame is determined using the frequency table, the value of the transmission throughput is updated within the range of the maximum value or less, and the updated transmission throughput is used. Transmission throughput that causes frame relay terminals to transmit frames Frame relay terminal, characterized in that it comprises a processing section. 2. The frequency table has a plurality of entries, and the number of times of receiving congestion notifications received within the range of the transmission throughput is divided into a plurality of values of the range of possible values of the transmission throughput. The transmission throughput management unit includes a frequency update processing unit that updates the frequency table at a predetermined cycle, and the frequency update processing unit is recorded in each of all entries in the frequency table. The frame relay terminal according to claim 1, wherein the number of times of receiving the congestion notification is reduced by a predetermined amount. 3. The frame relay terminal further comprises a mode recognition processing unit, and the mode recognition processing unit recognizes a transmission mode of the frame relay terminal and updates the transmission throughput based on the recognition mode. 2. It is determined whether or not to carry out in a range less than or equal to the maximum value of.
Frame relay terminal described in. 4. The frame relay terminal comprises a frame relay router to which one or more data processing devices are connected, and the frame relay router communicates with the frame relay network in a frame relay format. , Communication with the data processing device in a format other than a frame relay format, the mode recognition processing section comprises a control code recognition processing section provided with a control code table, and the control code table is the frame relay format. A control code is stored in association with a higher-level application for communication in a format other than the frame relay format between the router and the data processing device, and the control code recognition processing unit stores the control code corresponding to the higher-level application. Read out from the control code table and send out according to this control code Frame Relay terminal according to claim 3, wherein the determining whether to perform frame of delivery of the maximum value below the value of the throughput. 5. The frame relay terminal comprises a frame relay router to which one or more data processing devices are connected, and the frame relay router communicates with the frame relay network in a frame relay format. , Communication with the data processing device in a format other than a frame relay format, the mode recognition processing section is composed of a higher application recognition processing section having a higher application table, and the higher application table is the frame relay An upper application for communication in a format other than the frame relay format between the router and the data processing device is stored, and the upper application recognition processing unit reads the upper application from the upper application table and stores the upper application. Frame Relay terminal according to claim 3, wherein the determining whether to perform the transmission of the frame at the maximum value below the value of the delivery throughput accordance emissions. 6. A frame relay terminal control device connected to a frame relay network and transmitting and receiving frames to and from the frame relay network, comprising: a transmission throughput measuring unit for monitoring a frame transmission throughput to the frame relay network; A congestion notification monitoring unit that monitors reception of a congestion notification from a frame relay network, a frequency table that accumulates the results of monitoring in the transmission throughput measurement unit and the congestion notification monitoring unit, and in the transmission throughput measurement unit and the congestion notification monitoring unit A control device for a frame relay terminal, comprising: a transmission throughput management unit that creates the frequency table based on a result of monitoring and determines a maximum value of a frame transmission throughput using the frequency table. 7. A communication system comprising a frame relay network and a plurality of frame relay terminals connected to the frame relay network for transmitting and receiving frames to and from the frame relay network, wherein the frame relay network is the source frame While sending the frame sent from the relay terminal to the frame relay terminal of the destination, performs congestion notification to the frame relay terminal when congestion occurs, the frame relay terminal, the frame to the frame relay network , A congestion notification monitoring unit that monitors the reception of congestion notifications from the frame relay network, and a frequency table that accumulates the results of monitoring in the transmission throughput measuring unit and the congestion notification monitoring unit. Of the transmission throughput measuring unit and the congestion notification monitoring unit The frequency table is created based on the result, the maximum value of the frame transmission throughput is determined using the frequency table, the transmission throughput is updated within the range of the maximum value, and the frame is updated with the updated transmission throughput. And a transmission throughput management unit that causes the relay terminal to transmit a frame and, when a congestion notification is received, causes the frame relay terminal to transmit a frame at a predetermined value smaller than the maximum value of the transmission throughput. Characterized communication system. 8. A terminal, which is connected to a network and transmits / receives data to / from this network, monitors a transmission rate measuring unit that monitors a data transmission rate to the network, and monitors reception of a congestion notification from the network. A congestion notification monitoring unit, a frequency table for accumulating monitoring results in the transmission rate measuring unit and the congestion notification monitoring unit, and creating the frequency table based on the monitoring results in the transmission rate measuring unit and the congestion notification monitoring unit In addition, the terminal includes a transmission rate management unit that determines the maximum value of the data transmission rate using the frequency table and causes the terminal to transmit the data at a value equal to or less than the maximum value. 9. A control device of a terminal connected to a network for transmitting and receiving data to and from a network, comprising: a transmission rate measuring unit for monitoring a data transmission rate to the network; and a congestion notification from the network. A congestion notification monitoring unit that monitors reception, a frequency table that accumulates monitoring results in the transmission speed measurement unit and the congestion notification monitoring unit, and the frequency based on the monitoring result in the transmission speed measurement unit and the congestion notification monitoring unit. A control device for a terminal, comprising: a transmission rate management unit that creates a table and determines the maximum value of the data transmission rate using the frequency table. 10. A communication system comprising a network and a plurality of terminals connected to the network for transmitting and receiving data to and from the network, wherein the network transmits data transmitted from the source terminal to a transmission destination. While sending to the terminal of, performs congestion notification to the terminal when congestion occurs, the terminal, a transmission rate measurement unit for monitoring the transmission rate of data to the network, congestion notification from the network A congestion notification monitoring unit that monitors the reception of a frequency table that accumulates the results of monitoring in the transmission rate measurement unit and the congestion notification monitoring unit,
While creating the frequency table based on the result of monitoring in the transmission rate measurement unit and the congestion notification monitoring unit, the maximum value of the transmission rate of the data is determined using the frequency table and the value is less than or equal to the maximum value. And a transmission rate management unit that causes the terminal to transmit data and, when receiving a congestion notification, causes the terminal to transmit data at a predetermined value smaller than the maximum value of the transmission rate. Communications system. 11. A transmission throughput control method in a communication system comprising a frame relay network and a plurality of frame relay terminals connected to the frame relay network for transmitting and receiving frames to and from the frame relay network, the frame relay terminal comprising: The result of monitoring the frame sending throughput to the frame relay network, and the maximum value of the frame sending throughput based on the result of monitoring the congestion notification from the frame relay network is determined. The frame relay network, when the congestion occurs, the frame relay terminal notifies the frame relay terminal of congestion, the frame relay terminal, the frame relay network, Maximum throughput when receiving congestion notification from There line transmission of frame small predetermined value than the value, and the frame relay terminal, the frame relay network
Frame transmission throughput monitoring result and the frame
Based on the monitoring result of congestion notification from the ram relay network,
Divided the range of possible values of sending throughput into multiple
Received within the range of the transmission throughput for each area.
Record the number of received congestion notifications in multiple entries
Create a frequency table based on
Is used to determine the maximum frame throughput.
In addition, the frequency table is added to all the entries in a predetermined cycle.
About the number of received congestion notifications recorded for each is a predetermined amount
The transmission throughput control method is characterized by reducing 12. A frame relay terminal connected to a frame relay network and transmitting and receiving frames to and from the frame relay network, the congestion notification monitoring unit monitoring reception of a congestion notification from the frame relay network, and the frame relay network. And means for determining the transmission rate of the line connecting the frame relay terminal, and based on the result of the monitoring in the congestion notification monitoring unit, when the congestion notification is not received, by performing a predetermined calculation on the transmission rate A maximum value of the transmission throughput determined by the dynamic determination processing unit that determines the maximum value of the transmission throughput by increasing the maximum value of the transmission throughput larger than the current value by the obtained increase amount. e Bei and sending throughput management unit to perform transmission of frames to the frame relay terminal in value, and wherein the frame Li Over terminal further mode recognition process
And a mode recognition processing unit for transmitting the frame relay terminal.
Recognize outgoing mode and receive congestion notification based on this
If not, the maximum value of sending throughput is
The time during which the transmission throughput is increased
A frame relay terminal characterized by determining the distance . 13. The frame relay terminal comprises a frame relay router to which one or more data processing devices are connected, and the frame relay router communicates with the frame relay network in a frame relay format. , Communication with the data processing device in a format other than a frame relay format, the mode recognition processing section includes a higher application recognition processing section including a higher application table, and the higher application table is the frame relay router. And an upper application of communication in a format other than the frame relay format between the data processing apparatus and the data processing apparatus and a time interval parameter corresponding thereto are stored, and the upper application recognition processing unit recognizes the upper application. , Based on this If the time interval that has elapsed since the corresponding time interval parameter was read from the application table and the transmission throughput increasing process was performed prior to this time interval parameter is large, the maximum value of the transmission throughput will be made larger than the current value. The frame relay terminal according to claim 12, which performs processing. 14. A frame relay network, multiple transmitting and receiving frames to and from which is connected to the frame relay network
In a communication system comprising a number of frame relay terminals, the frame relay network sends the frame transmitted from the frame relay terminal of the transmission source to the frame relay terminal of the transmission destination, and the frame when congestion occurs Performing congestion notification to the relay terminal, the frame relay terminal, the congestion notification monitoring unit to monitor the reception of congestion notification from the frame relay network, of the line connecting the frame relay network and the frame relay terminal Based on the result of monitoring by the means for determining the transmission rate and the congestion notification monitoring unit, when the congestion notification is not received, the maximum value of the transmission throughput by the amount of increase obtained by performing a predetermined calculation on the transmission rate Is set to a value larger than the current value, and when the congestion notification is received, the CIR is subjected to a predetermined calculation. The dynamic determination processing unit that determines the maximum value of the transmission throughput by making the maximum value of the transmission throughput smaller than the current value by the amount of the calculated reduction amount, and the transmission throughput determined by the dynamic determination processing unit. And the mode recognition process that causes the frame relay terminal to transmit a frame at the maximum value of
The mode recognition processing unit is provided with a frame processing unit.
The transmission mode of the wireless terminal is recognized, and the
If you do not receive the congestion notification
Processing to increase the transmission throughput that is larger than the current value
A communication system, characterized in that a time interval for performing is determined . Is connected to 15. network, the terminal for transmitting and receiving data to and from this, the line connecting the congestion notification monitoring unit for monitoring the reception of a congestion notification from the network, and said network and said terminal Based on the result of the monitoring in the congestion notification monitoring unit, when the congestion notification is not received, the transmission speed of the data by the amount of increase obtained by performing a predetermined calculation on the transmission speed When the congestion notification is received, the maximum value of is set smaller than the current value, and the maximum value of the data transmission rate is made smaller than the current value by the amount of decrease obtained by performing a predetermined calculation on the CIR. By doing so, a dynamic determination processing unit that determines the maximum value of the data transmission rate, and transmission rate management that causes the terminal to send data at the maximum value of the data transmission rate determined by the dynamic determination processing unit Department And a mode recognition processing unit, and the mode recognition processing unit
Recognizes the transmission mode of the frame relay terminal
Based on this, if the congestion notification is not received based on
Sends a loop with a maximum value greater than the current value.
A terminal characterized in that it determines a time interval for performing a loop up process . 16. A communication system comprising a network and a plurality of terminals connected to the network for transmitting and receiving data to and from the network, wherein the network transmits the data transmitted from the source terminal to the destination. While sending to the terminal of, performs congestion notification to the terminal when congestion occurs, the terminal, a congestion notification monitoring unit that monitors the reception of congestion notification from the network, the network and the terminal Means for determining the transmission rate of the line connecting the, based on the result of monitoring in the congestion notification monitoring unit, when not receiving a congestion notification,
By increasing the maximum value of the data transmission rate by the amount of increase obtained by performing a predetermined calculation on the transmission rate than the current value and performing a predetermined calculation on the CIR when a congestion notification is received. A dynamic determination processing unit that determines the maximum value of the data transmission rate by making the maximum value of the data transmission rate smaller than the current value by the obtained reduction amount, and the determination of the dynamic determination processing unit The mode recognition processing unit is provided with a transmission speed management unit that causes the terminal to transmit the data at the maximum value of the data transmission speed.
The management unit recognizes the transmission mode of the frame relay terminal.
And if it does not receive a congestion notification based on this, send
Sending the maximum throughput value higher than the current value
A communication system characterized by determining a time interval for performing throughput increasing processing . 17. A transmission throughput control method in a communication system comprising a frame relay network and a plurality of frame relay terminals connected to the frame relay network and transmitting and receiving frames to and from the frame relay network, wherein the frame relay network comprises: While sending a frame sent from the frame relay terminal of the transmission source to the frame relay terminal of the transmission destination, performs congestion notification to the frame relay terminal when congestion occurs, the frame relay terminal, the congestion Based on the result of the monitoring by the notification monitoring unit, when the congestion notification is not received, only the amount of increase obtained by performing a predetermined calculation on the transmission speed of the line connecting the frame relay network and the frame relay terminal. Increase the maximum value of the sending throughput from the current value, and Sends a frame at the maximum value of put, the frame relay network, when congestion occurs, performs a congestion notification to the frame relay terminal, the frame relay terminal receives the congestion notification from the frame relay network In this case, the maximum value of the transmission throughput is made smaller than the current value by the amount of reduction obtained by performing a predetermined calculation on the CIR, and the frame is transmitted at the reduced maximum value of the transmission throughput. And a transmission throughput control method.