JP3211827B2 - Packet 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 traffic control in a packet switching system, and more particularly to ATM (asyn
The present invention relates to a packet communication system which introduces traffic control or the like suitable for regulation such as monitoring / discarding of received cells in switching and marking, and the like, and enables more stable communication services to be provided.

[0002]

2. Description of the Related Art In an ATM exchange, a subscriber terminal declares parameters of a traffic called a cell transmitted during a call setup to a network (exchange) at the time of a call when the call is originated. It has been proposed to perform bandwidth allocation based on this. Conventionally, a method of monitoring traffic in a packet communication system is to assign a weighted value to the passage of a packet in a past sampling period that is retroactive from the measurement time, hold a sum of the values in a counter, and store the sum in a counter. When the counter exceeds a certain value while updating the counter along with the transition of, the packet passing frequency is determined to be excessive, and the single leaky bucket method can be considered as one of them. Also, if a terminal transmits a packet exceeding the declared traffic, congestion occurs and a problem such as an increase / loss of a packet transmitted from another terminal occurs.
In the exchange, it is necessary to monitor the traffic from the terminal and take measures such as discarding if there is an excess.

[0003]

In a packet communication system, if the amount of incoming packets exceeds the processing capacity, normal connection of packets cannot be performed.
In order to provide more stable communication, it is necessary to constantly monitor packet traffic.

Here, in the traffic monitoring in the packet communication system, there is a case where each packet is monitored to see whether or not the packets pass collectively within a short time. For example, in monitoring the frequency of arrival of cells in an ATM switch that handles packets called cells, the overflow rate of cells in the switch depends on whether or not the traffic repeatedly arrives in a short time. Such monitoring is important because it is so affected. A group of cells arriving in a short time is called a burst. That is, ATM
In switching, it is necessary to monitor whether or not a cell has arrived as a burst, and if so, whether the size of the burst is within an allowable range. When the prior art of the preceding paragraph is applied to the monitoring of the burst property, the cells arriving as a burst during the sampling period are also weighted in the same manner as the cells arriving at different intervals, so that they arrive at the counter as a burst. There is a first problem that it is difficult to accurately monitor the arrival of a burst without being reflected.

It is an object of the present invention to provide a more stable packet communication system by solving such a problem and providing a monitoring device capable of detecting that packet passing has occurred in a short time. is there.

Further, in the above-mentioned prior art, the restriction of discarding or delay is applied to a certain cell when the monitoring mechanism determines that the received traffic exceeds the declared traffic due to the arrival of the cell. . For this reason, the ratio of cells regulated by the frequency of detecting the excess of the traffic excess detection frequency track by the monitor mechanism is determined. However, in general, the frequency of detection of excess traffic does not match the ratio of cells to be regulated (frequency of occurrence of cells to be regulated). Therefore, in the above prior art, if the traffic excess detection frequency of the monitoring mechanism is not adjusted so that the traffic excess detection frequency and the ratio of regulated cells are adjusted, the amount of cells subject to regulation becomes excessive. There was a problem of lack. Further, in the above-described conventional technology, the fact that the cell is regulated is not reflected on the monitor mechanism. That is, the monitoring mechanism monitors the traffic including the regulated cells.As a result, the monitoring mechanism continuously detects the excess of the traffic regardless of whether the traffic of the cells passing unregulated is larger or smaller than the declared traffic. There is a second problem that the amount of target cells becomes excessive or insufficient.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problem and to provide a packet communication system having a higher execution rate, provided with a monitor device or the like in which the ratio of regulated cells does not become excessive or insufficient. is there.

[0008]

In order to achieve the above object, the present invention monitors traffic of a packet input from the input path, compares the traffic with a predetermined threshold value, and A monitoring device that issues an excess notification when the threshold value is exceeded; a packet control device that controls a packet input within a predetermined control period when receiving the excess notification issued by the monitoring device; And a connection device for connecting a packet not controlled by the packet control device to an output path to be output. In order to achieve the above object, according to the present invention, the packet control device is arranged in front of the monitor device for a packet input, and a packet controlled by the packet control device is excluded from monitoring by the monitor device. It has this configuration. In order to achieve the above object, the present invention sets the control period of the packet control device to be long for a monitor device in which traffic excess detection is frequent, and is short for a monitor device in which traffic excess detection is rare. It has a configuration to set. In order to achieve the above object, the present invention provides an input means for inputting a packet from outside, and a traffic control means for controlling traffic of an input packet connected to the input means according to a predetermined condition and outputting the packet. Connection means for connecting a packet output from the traffic control means to a path different from the input path, first monitoring means for monitoring the maximum bandwidth of the traffic, and monitoring the average bandwidth of the traffic And a second monitoring means for controlling the traffic on the basis of a monitoring result of either the first monitoring means or the second monitoring means.

In order to achieve the above object, the present invention comprises a plurality of monitoring means for monitoring packet traffic within different monitoring times, and the traffic control means controls a monitoring result of any of the plurality of monitoring means. On the basis of the traffic.

[0010] To achieve the above object, the present invention provides a first monitoring means for monitoring packet traffic within a first monitoring time at a monitoring point in a packet communication system; Second monitoring means for monitoring packet traffic within a different second monitoring time.

In order to achieve the above object, the present invention provides a first leaky bucket for monitoring a maximum bandwidth of the traffic, a burst length monitoring device for monitoring a burst state of the traffic, and an average bandwidth of the traffic. A second leaky bucket to be monitored, and the traffic control device controls the traffic based on a monitoring result of any of the first leaky bucket, the burst length monitoring device, and the second leaky bucket. .

[0012] To achieve the above object, the present invention provides an arithmetic unit comprising a plurality of serially connected arithmetic means for performing an arithmetic operation based on a packet input to the packet communication system and outputting an arithmetic result, A burst traffic monitoring device that monitors burst traffic based on a calculation result of the calculation unit; and a switch that switches a packet input to the input path to an appropriate output path based on a monitoring result of the burst traffic monitoring device. An exchange switch, wherein in the operation unit, the number of packets input from the input path is input to the first operation unit among the operation units arranged in series, and the operation unit in the second and subsequent stages from the top Has a configuration in which the operation result of the immediately preceding operation unit is input, and the output of the last operation unit is output as the operation result of the operation unit.

[0013]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a diagram showing a configuration of an ATM exchange to which the present invention is applied. In Figure 1, the trunk line of the exchange, etc.
Parts unnecessary for the description of the present invention are omitted.

The ATM exchange 12 shown in FIG. 1 has an exchange control unit 13, a subscriber circuit 14, and a switch 19 as main parts. The three parties operate as follows when the terminal 11 communicates. That is, first, the terminal 11 divides a call setting signal into a packet called a cell through the subscriber line link 111 to the ATM exchange 12 and transmits the packet, and receives the signal by the exchange control unit 13 in the ATM exchange 12. The switching control unit 13 sets the subscriber circuit 14 and the switch 19 to a state in which the terminal can perform communication based on the parameters of the call setting signal. During communication, the terminal 11 breaks down the information data into cells and transmits them to the exchange 12 through the subscriber line information link 112. The information cells are input to the switch 19 via the subscriber circuit 14, and are transmitted to the switch 19 to the destination. Is performed.

FIG. 10 shows the operation performed by the exchange control unit 13.
4 shows a flow of a setting process for the subscriber circuit 14 when a call setting signal is received. Hereinafter, in FIG. 10, the frequency of detection of the excess of the declared traffic in the block 1002 and the blocks 1003 to
The addition values 1, 2, 3, 4 and the subtraction values 1, 2,
The method for determining the parameters 3, 4 and the threshold values 1, 2, 3, 4 will be described in detail.

In the above parameters, the added values 1, 2, 2,
3,4, subtraction rate 1,2,3,4, threshold value 1,2,3
4 is a parameter of the leaky bucket. Referring to FIGS. 2 to 6, the aforementioned A using a leaky bucket mechanism will be described.
The traffic monitoring in the TM exchange is summarized, and thereafter, referring to FIGS. 7 to 9, the leaky bucket front stage 18 in the average burst length monitoring unit 183 according to the present invention is particularly used.
4, and parameters of the leaky bucket second stage 185,
A method of determining the addition values 3 and 4, the subtraction rates 3 and 4, and the threshold values 3 and 4 will be described.

FIG. 2 shows an example of a change in the counter of the leaky bucket mechanism. In FIG. 2, a ratio between the subtraction value and a fixed period for performing the subtraction is defined as a subtraction rate (Rsub).

FIG. 3 shows the interpretation of the parameters in FIG. 2 when the leaky bucket mechanism is viewed as a kind of queuing system. In FIG. 3, reference numeral 32 denotes a queue model of the leaky bucket mechanism, in which there are 31 monitoring events as an input, and there is a queue length overflow as an output, which means that 33 monitoring events are excessively generated. In FIG.
The addition value Nadd and the subtraction rate Rsu which are the parameters in FIG.
b, the threshold value Nmax determines the parameter holding time h of the queue system 32 and the number m of waiting rooms. The holding time h and the number of waiting rooms m determine the nature of the leaky bucket, as shown at 34. That is, the addition value Nadd, the subtraction value Rsub, and the threshold value Nmax are not independent of each other,
If the holding time h and the number of waiting rooms m are determined, one of the three may be fixed and the other two may be determined.

FIG. 4 shows the allocated bandwidth for the type of traffic to be monitored, its distribution, and the monitoring parameters.
The monitoring parameters in FIG. 4 are the maximum bandwidth monitoring leaky bucket 181 in FIG. 1, the maximum bandwidth is the average bandwidth monitoring leaky bucket 182 in FIG. 1, and the average burst length is the average burst length monitoring in FIG. In part 183,
Be monitored. Hereinafter, regarding the traffic shown in FIG.
When an overflow occurs in the leaky bucket mechanism, it is determined that the traffic report value is violated, and a method of determining the parameters h (reservation time) and m (the number of waiting rooms) is qualitatively described.

First, a method of determining h (hold time) will be described.
The maximum bandwidth, the average bandwidth, and the burst length of the traffic monitoring parameters shown in FIG. 4 differ in the time scale for observing the frequency of cell arrival. This corresponds to the time scale of seeing <1> input changes in the nature of the leaky bucket mechanism described in FIG.

FIG. 5 shows the correspondence between the monitoring parameters and the properties of the leaky bucket <1> in FIG. h
The determination scale of (reservation time) is shown. The figure shows that, for example, when it is desired to monitor the average band, the value of h (reservation time) should be increased, and therefore the ratio between Nadd and Rsub should be increased.

Next, a method of determining m (the number of waiting rooms) will be described. In order to effectively discriminate between traffic that does not violate the declared value and traffic that violated, increase the difference between the overflow probabilities of the two and make the absolute value of the overflow probability occur within a significant monitoring time, m and h must be determined. The property and are in a trade-off relation, and correspond to the property of <2> in FIG. Since h has restrictions in the selection of monitoring parameters, m is used to determine the optimal trade-off relationship with h.

FIG. 6 shows the violation detection accuracy and the violation detection time,
A determination scale for m (the number of waiting rooms) in accordance with the property of the leaky bucket mechanism of <2> in FIG. 334 is shown.

As described above, referring to FIG. 2 to FIG.
The traffic monitoring in the ATM switch using the bucket mechanism was organized. With this arrangement, it is possible to determine each parameter of the addition value 1, the subtraction rate 1, the threshold value 1, and the addition value 2, the subtraction rate 2, and the threshold value 2, and the traffic excess detection frequency. That is, the addition value 1, the subtraction rate 1,
For a threshold value of 1, a leaky
Because of the bucket parameters, h
(Holding time) is determined, and m (the number of waiting rooms) is determined using FIG. 6 from the viewpoint of the accuracy of traffic excess detection. By determining m (the number of waiting rooms), the traffic excess detection frequency is determined, and if one of the three parameters of addition value 1, subtraction rate 1, and threshold value 1 is fixed, two parameters of the value are determined. . The addition value 2, the subtraction rate 2, and the threshold value 2 can also be determined in the same way by being parameters of the leaky bucket for monitoring the average band.

Next, the operation of the average burst length monitor 183 in FIG. 1 having a multi-stage leaky bucket mechanism will be described with reference to FIGS. 3 and a method of determining each parameter of an addition value 4, a subtraction rate 4, and a threshold value 4 are shown.

FIG. 7 shows the average burst length monitor 1 shown in FIG.
It is a figure showing the internal configuration of 83. 7, the average burst length monitor 183 has two leaky bucket mechanisms 184 and 185. At the time of call setting, in the leaky bucket former stage 184, the registers 1841 to 184 are passed through the parameter setting unit 713 determined by the exchange control unit 13 based on the traffic report parameter indicated in the call setting signal.
3 is stored. At the same time, the counter register 3 (C
1,715) is cleared to zero. After the communication is started, the arithmetic unit 711 operates the registers 1841 to 184.
An operation is performed on 3,715. That is, the regulation unit 1
When a cell is input from the switch 7 to the switch 19, the operation unit 71
1 is to counter register 3 (C1, 715)
The value of the addition value register 3 (Nadd3, 1841) is added. When the timer 712 is activated at regular intervals, the arithmetic unit 711 causes the counter register 3 (C1,
715) is subtracted by the value of the product of the subtraction rate register 3 (Rsub1, 1842) and a fixed period so that the result does not become negative. Also, the overflow detection unit 714
Indicates that the cell is input from the regulating unit 17 to the switch 19, and the calculation unit 711 causes the counter register 3 (C1, 715)
Is added, the counter register 3 (C1,
715) and threshold register 3 (Nmax1, 184)
3) and compare with counter register 3 (C1, 7
15) is the threshold value register 3 (Nmax1, 1843)
If it is larger, the overflow of the counter 3 (C1, 715) is passed to the latter stage 185 of the leaky bucket. The internal operation of the leaky bucket rear stage 185 is the same as that of the leaky bucket front stage 184. That is,
When receiving the notification of the overflow of the leaky bucket former stage 184, the arithmetic unit 721 sets the counter register 4 (C
2, 725), the addition value register 4 (Nadd
2, 1851). Counter register 4
(C2, 725) is the threshold value register 4 (Nmax2,
1853), the overflow detector 7
24 notifies the regulating unit 17 of an excess of declared traffic of the average burst length. The parameter of the leaky basket first stage 184 is determined to monitor the burst length based on the determination scale of h (retention time) shown in FIG. Therefore, the ratio between the addition value 3 and the subtraction rate 4 is set small. The parameters after the leaky bucket 185 are determined so as to monitor the average band based on the determination scale of h (reservation time) shown in FIG. Therefore, the ratio between the added value 4 and the subtraction rate 4 is set to be large. Next, if m (the number of waiting rooms) is determined with reference to FIG. 6 from the viewpoint of the accuracy of the detection of excess traffic, the added value 3, the subtraction rate 3, the critical 3, and the added value 4, the subtraction rate 4, the critical value 4 are determined.

In FIG. 7, although the former stage of the leaky bucket and the latter stage of the leaky bucket are configured independently, the registers 715, 725, 1841, 1842, 1
Portions other than 843, 1851, 1852, 1853
Both can be common.

FIGS. 8 and 9 show the multi-stage configuration 2 shown in FIG.
5 shows an example of a change in a counter of two leaky bucket mechanisms. 8 shows a case where the average burst length is short, and FIG. 9 shows a case where the average burst length is long. (A) in FIG.
81, (a) 91 in FIG. 9 shows the arrival of the cell over time, and (b) 82 in FIG. 8 and (b) 92 in FIG.
The counter register 3 (C1, 7
(C) 83 in FIG. 8 and (c) 93 in FIG. 9 indicate changes with time in the counter register 4 (C2, 725) of the latter stage 185 of the leaky bucket, respectively. Show.

8 (b) 82 and FIG. 9 (b) 92
According to the determination scale of h (hold time) in FIG. 5, when the burst length is used as a monitoring parameter, this corresponds to a change in the counter of the leaky bucket mechanism having a one-stage configuration. Here, (b) 82 in FIG. In both cases of (b) 92 in FIG. 9, an overflow has occurred. In contrast, (c) 83 in FIG. 8 and (c) 93 in FIG.
9 (b) and 9 (b) due to the difference in the average burst length.
One cell arrival has been identified. That is, at (a) 91 in FIG. 9, the cells arrive as a burst in a short time, and the counter of the leaky bucket mechanism 83 in the preceding stage in which h (reservation time) in (b) 92 in FIG. C1 overflows in response to the burst, and FIG.
The counter C2 of the leaky bucket mechanism 84 at the subsequent stage where h (reservation time) of the middle (c) 93 is lengthened overflows due to a long-term monitoring result of the occurrence of the burst.

Next, referring to FIG. 1, the regulating unit 1 in FIG.
7 will be described.

First, the operation at the time of call setting will be described. FIG.
As shown in a block 1006 in the flow diagram of FIG. 0, at the time of call setup, the restriction period length determined by referring to the declared traffic parameter indicated in the call setting signal is determined by the restriction unit 17. Is set in the regulation period length register 172. At the same time, the regulation unit 17 is initialized. When the initial setting of the regulating unit 17 is completed, the discard switch 174
The terminal 176 is connected to the terminal 175 so that an input from the information link 112 is output to the traffic monitor unit 18.

The time during communication after a call is set up and communication is started is divided into two cases, a restricted period and a non-restricted period. Terminal 176 in discard switch 174 in FIG.
However, the time connected to the terminal 175 is a non-regulation period, and the time connected to the terminal 177 is a non-regulation period. Therefore, immediately after the call setting, the non-regulation period is set as described above.

Next, the operation during the non-regulation period will be described with reference to FIG. In FIG. 1, the information cell sent from the terminal 11 to the exchange 12 via the information link 112 is:
After being received by the cell receiving unit 16, it is sent to the discard switch 174 in the regulating unit 17. As described above, since the terminal 176 in the discard switch 174 is connected to the terminal 175 during the non-regulation period, the received cell is
It is sent to the monitor 18. In this way, only the cells that have passed through the discard switch and have not been regulated are monitored by the traffic monitor unit 18.

Next, the operation at the time of shifting from the non-regulation period to the restriction period will be described with reference to FIG. When the frequency of cell arrival exceeds the declared traffic level, the traffic monitor unit 18 notifies the regulation control unit 171 that the received traffic has exceeded the declared traffic. Upon receiving the notification, the regulation control unit 171 reads the regulation period length set at the time of the initial setting from the regulation period register 172, and registers the timer 173 with the timer so that the regulation control unit 171 is activated after the regulation period length has elapsed. At the same time, the discard switch 174 is set, and the terminal 176 is connected to the terminal 177.
Belongs to.

Next, the operation during the regulation period will be described with reference to FIG. During the restriction period, the output of the empty cell generator 178 is output to the traffic monitor 18. Therefore, the traffic monitor unit does not monitor the received information cell. The information cell transmitted from the terminal 11 via the information link 112 and received by the cell receiving unit 16 is discarded by the cell discard switch 174.

Next, the operation at the time of transition from the regulation period to the non-regulation period will be described with reference to FIG. When the timer 173 activates the regulation control unit 171 after the regulation period length has elapsed,
The regulation control unit sets a discard switch, and connects the terminal 176 to the terminal 175. That is, the cell received from the terminal 11 received by the cell receiving unit 16 is output to the switch 15 via the traffic monitoring unit 18, and the restricted period ends and shifts to the non-restricted period.

FIG. 11 is a diagram showing an example of the arrival of a cell that has exceeded the declared traffic. Hereinafter, it will be described with reference to FIG. 11 that the amount of regulated cells can be adjusted by setting the regulation period length.

In FIG. 11, the regulation period starts when the cell G arrives, and thereafter, cells arriving during the regulation period are discarded as described with reference to FIG. In FIG. 11, 3
This shows a case where two different restriction period lengths are set, and the restriction period length is set to be shorter than the restriction period I1.
102, regulation period II 1103, regulation period III 110
4 indicates the range. When the restriction period I1102 is set, four cells from cell H to cell K are restricted and discarded. When the restriction period II 1103 is set, eight cells from cell H to cell O are restricted and discarded. When the restriction period III1104 is set, twelve cells from cell H to cell S are restricted and discarded. That is, as the set value of the regulation period length is larger, more cells are regulated, and as the set value of the regulation period length is smaller, fewer cells are regulated. Therefore, the ratio of cells to be regulated can be adjusted by setting the regulation period length.

FIG. 12 is a conceptual diagram showing the relationship between the regulation mechanism 17 and the traffic monitor mechanism 18 shown in FIG. When the frequency of arrival of the reception cell 1201 increases and the excess of the declared traffic is detected, the monitor mechanism 1203 notifies the regulation mechanism 1202 of the traffic excess detection at a frequency according to the excess detection frequency 1207 specific to the monitor method.
In the regulation mechanism 1202 that has received the notification, the amount of cells proportional to the set regulation period 1206 is regulated, and the monitoring target of the monitoring mechanism is reduced. That is, the traffic excess detection notification from the monitoring mechanism to the regulation mechanism functions as a feedback loop 1205. Therefore, the desired traffic amount of the output cell 1208 can be determined by setting the excess detection frequency 1207 and the restriction period 1206.

FIG. 13 is a diagram showing an example of arrival of cells exceeding the declared traffic when the frequency of detection of excess traffic by the monitor mechanism is different. Hereinafter, FIG.
The setting of the regulation period length in accordance with the traffic excess detection frequency specific to the regulation mechanism will be described with reference to FIG. As shown in FIG. 6, an appropriate value is selected for the traffic excess detection frequency depending on the trade-off relationship with the traffic excess detection accuracy, and therefore takes different values depending on the parameters of the traffic monitor. In FIG. 13, (a) 1301 is a monitor mechanism with a low excess detection frequency, (c) 1303 is a monitor mechanism with a frequent excess detection frequency, and (b) 1302 is a monitor mechanism with a low excess detection frequency. ) 1303, respectively. On the other hand, from the longest regulation period, (a) 1301,
The order is (b) 1302 and (c) 1303. As a result, the number of cells to be discarded is the same regardless of the difference in the traffic excess detection frequency specific to the monitor mechanism. As to which cells are discarded, (a) 130
1, (b) 1302, and (c) 1303 are different, and (a) 1301, (b) 1302, (c) 1303
In this order, cell discarding is performed intensively. That is, conversely, it is also possible to set the pattern in which the cell is discarded by adjusting the restriction period length of the parameter of the restriction mechanism and the frequency of detecting excess traffic of the monitor mechanism.

In this embodiment, an example in which cells are discarded as a regulation has been described.
The same can be applied. In this case, the discard switch 174 shown in FIG.
The monitor unit 18 may exclude the marked cell from the monitoring target.

FIG. 14 is a diagram showing an internal configuration in the case where the average burst monitoring unit is realized using an arrival number counter.

In FIG. 14, the average burst length monitor 140
4 has two arrival number counters 1405, 1406. At the time of call setup, in the first stage of arrival number counter 1404, the parameters determined by the exchange control unit based on the traffic report parameters indicated in the call setup signal are stored in the parameter setting unit 1
The data is accumulated in the key value register 14055 through the line 4053. At the same time, the counter register 3 (C1, 1405
6) is cleared to zero. After the communication is started, the arithmetic unit 14051 operates the threshold value register 14055 and the counter register 3 (C1, 14056). That is, when a cell is input to the switch 1403 from the restricting unit 1401, the calculating unit 14051 increments the counter register 3 (C1, 14056). When activated by the timer 14052 at regular intervals, the overflow detection unit 14054 compares the counter register 3 (C1, 14056) with the threshold register 3 (Nmax1, 14056). If (C1, 14056) is larger than the threshold value register 3 (Nmax1, 14055), the counter 3 (C1,
14056). The operation inside the arrival number counter 1406 is based on the arrival number counter 1
Same as 405. That is, the first stage of the arrival number counter 1
The arithmetic unit 1 receives the overflow notification from the
4061 is a counter register 4 (C2, 14056)
Is incremented. Counter register 4 (C2,
14066) is the threshold register 4 (Nmax2, 14)
065), the restriction unit 1401
Notification of excess declared traffic of average burst length. A small value is set in the threshold value register 3 (Nmax1, 14055), and a large value is set in the threshold value register 4 (Nmax2, 14065).

FIG. 17 shows an example of a change in the counters of the two arrival number counters of the multistage configuration in FIG. That is, at (a) 1701 in FIG. 17, cells arrive as a burst in a short time, and
Arrival number counter previous stage 1 in the previous stage where the threshold value of 02 was shortened
The counter C1 at 405 overflows in response to the burst, and the counter C2 at the latter stage of the arrival number counter 1406 after the threshold value of (c) 1703 in FIG. 17 is increased due to the long-term monitoring result of the occurrence of the burst. ing.

FIG. 15 is a diagram showing an internal configuration in the case where the average burst monitoring unit is realized using an arrival interval measuring device.

In FIG. 15, the average burst length monitor 150
4 has two arrival interval measuring devices 1505, 1506. At the time of call setting, the arrival interval measuring device upstream stage 1504 determines the parameters determined by the exchange control unit based on the traffic report parameters indicated in the call setting signal, by the parameter setting unit 1.
The data is stored in the threshold value register 15055 through the 5053. At the same time, the counter register 3 (C1, 150
57) is cleared to zero. After the communication is started, the operation unit 15051 operates the threshold value register 15055, the operation result register 3 (Asub1, 15056), and the counter register 3 (C1, 15057). That is, when a cell is input from the regulating unit 1501 to the switch 1503, the arithmetic unit 15051 calculates the counter register 3 (C1, 15) from the value of the timer 15052.
057), and subtraction result register 3 (Asu)
b1, 15056) and the counter register 3
The value of the timer 15052 is set in (C1, 15057). Subsequently, the overflow detection unit 15054 compares the subtraction result register 3 (Amax1, 15056) with the threshold value register 3 (Nmax1, 15055).
If the subtraction result register 3 (Asub1, 15056) is smaller than the threshold value register 3 (Nmax1, 14055), an overflow of the subtraction result register 3 (Asub1, 15056) is notified to the subsequent stage 1506 of the arrival interval measuring device. The internal operation of the arrival interval measuring device subsequent stage 1506 is as follows.
This is the same as the preceding stage 1505 of the arrival interval measuring device. That is,
Upon receiving the notification of the overflow from the arrival interval measuring device front stage 1505, the arithmetic unit 15061 subtracts the value of the counter register 4 (C2, 15067) from the value of the timer 15062, and the subtraction result register 4 (Asub2, 1506).
6), and set the counter register 4 (C1, 1506).
In 7), the value of the timer 15062 is set. Subsequently, the overflow detection unit 15064 sets the subtraction result register 4 (A
sub2, 15066) and threshold register 4 (Nma
x2, 15065), and the subtraction result register 4 (Asub2, 15066) is compared with the threshold register 4
If it is smaller than (Nmax2, 14065), the control unit 1501 is notified of an excess of the declared traffic of the average burst length. Threshold register 3 (Nmax1, 150
55) has a small value in threshold register 4 (Nmax).
2, 15065) is set to a large value. Therefore, when the cells arrive as a burst in a short time, the counter C1 of the preceding arrival interval measuring device 1505 in which the threshold value is shortened overflows in response to the burst, and the arrival number counter in the latter stage in which the threshold value is increased. The counter C2 in the subsequent stage 1506 overflows according to the monitoring result of the burst generation interval.

FIG. 16 is a diagram showing an internal configuration in a case where the average burst monitoring unit is realized using an arrival number counter and an arrival interval measuring device.

In FIG. 16, the average burst length monitor 160
4 is an arrival number counter 1605 and an arrival interval measuring device 160
It has six. The internal operation of the arrival number counter 1605 is as follows.
This is the same as the arrival number counter 1405 in FIG. The internal operation of the arrival interval measuring device 1606 is the same as that of the arrival interval measuring device 1506 in FIG. Threshold register 3
A small value is set in (Nmax1, 16055), and a large value is set in threshold register 4 (Nmax2, 16065). Therefore, when the cells arrive as a burst in a short time, the counter C1 of the arrival number counter 1605 in the preceding stage, which has shortened the threshold value, overflows in response to the burst, and the subsequent arrival number counter in the latter stage increases the threshold value. Counter C2 of 1606
Overflows depending on the result of monitoring the interval between occurrences of bursts.

It is also possible to realize a multistage average burst length monitoring unit using a frequency monitoring mechanism other than the leaky bucket, arrival number counter, and arrival interval measuring device described above.

[0051]

The leaky bucket mechanism at the preceding stage of the multi-stage leaky bucket mechanism overflows when packets collectively pass in a short time.
A short-term event such as when a cell arrives as the burst is detected and output to a leaky bucket mechanism at a subsequent stage. The leaky bucket mechanism at the subsequent stage monitors the occurrence frequency of a short-term event called passage of the burst in a long term. As a result, it is possible to reduce the probability of erroneously recognizing that the frequency of cell passage as a burst is excessive due to an accidental factor.

When the excess traffic is notified from the monitor mechanism, the regulation mechanism starts a regulation period and regulates cells arriving during the regulation period. Since the length of the restriction period is determined by the restriction period length, which is a parameter, the amount of cells to be restricted can be adjusted by setting the parameter of the restriction period length. Therefore, the ratio of cells subject to regulation can be set irrespective of the traffic excess detection frequency specific to the monitoring mechanism.

The cells regulated by the regulation mechanism are not counted as received cells by the monitor mechanism. That is, only when the traffic that passes without restriction is larger than the declared traffic, the monitor detects the excess of the traffic and the restriction of the restriction mechanism is started. When a monitoring mechanism that frequently detects excess traffic is used for a certain amount of traffic that exceeds the declared traffic, the restriction period including the small number of cell arrivals is performed many times by setting a short restriction period length. Regulation takes place in the form. When a monitor mechanism that rarely performs excess detection is used, the regulation is performed in such a manner that the regulation period including the arrival of a large number of cells is performed a small number of times by setting a long regulation period length. As a result, the traffic of unregulated passing packets can be set to a desired size irrespective of the monitor-specific excess traffic detection frequency. In addition, since the regulated cells are not monitored by the monitor mechanism, the monitor mechanism can detect the excess of the traffic passing through the traffic that is not regulated by the traffic report. At this time, by setting the regulation period length in accordance with the traffic excess detection frequency specific to the monitor mechanism, it is possible to set the traffic of cells passing without regulation to a desired size.

By incorporating these devices in the switching system, more stable and highly efficient packet switching is realized.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an ATM exchange according to an embodiment of the present invention.

FIG. 2 is a diagram showing a graph of a change in a counter of a leaky bucket mechanism.

FIG. 3 is a schematic diagram of a leaky bucket mechanism as a queue system.

FIG. 4 is a diagram showing traffic types to be monitored in an ATM exchange;

FIG. 5 is a diagram showing a scale for determining a parameter h (hold time) of a leaky bucket mechanism.

FIG. 6 is a diagram showing a scale for determining a parameter m (the number of waiting rooms) of the leaky bucket mechanism.

FIG. 7 is an internal configuration diagram of an average burst length monitoring unit 183 in FIG. 1;

FIG. 8 is a graph showing a change in a counter of a multi-stage leaky bucket mechanism.

FIG. 9 is a graph showing a change in the counter of the multi-stage leaky bucket mechanism.

FIG. 10 is a flowchart of a process for the subscriber circuit 14 when the exchange control unit 13 in FIG. 1 receives a call setting signal.

FIG. 11 is a diagram showing an example of arrival of a cell exceeding declared traffic and a restriction period.

FIG. 12 is a conceptual diagram illustrating a relationship between a regulation mechanism and a traffic monitoring mechanism in FIG. 1;

FIG. 13 is a diagram showing an example of the arrival of a cell exceeding the declared traffic and a restriction period.

FIG. 14 is an internal configuration diagram of an average burst length monitoring unit configured by an arrival number counter.

FIG. 15 is an internal configuration diagram of an average burst length monitoring unit configured by an arrival interval measuring device.

FIG. 16 is an internal configuration diagram of an average burst length monitoring unit including an arrival number counter and an arrival interval measuring device.

FIG. 17 is a graph showing a change in the counter of the multi-stage arrival number counter mechanism.

[Explanation of symbols]

11 --- Terminal 111 --- Subscriber Line Signal Link 112 --- Subscriber Line Information Link 12 --- ATM Switch 13 --- Exchange Control Unit 14 --- Subscriber Circuit 15 --- Subscriber Circuit Control unit 16 --- Cell receiving unit 17 --- Regulator 171 --- Regulator control unit 172 --- Regulatory period length register 173 --- Timer, 174 --- Discard switch 175, 176, 177 --- Terminal 178 --- empty cell generator 18 --- traffic monitor 181 --- maximum bandwidth monitor leaky bucket 182 --- average bandwidth monitor leaky bucket 183 --- average berth and length monitor 184- --Leaky bucket front stage 185 --- Leaky bucket rear stage 1811,1821,1831,1841 --- Addition value register 1812,1822,1832,1842 --- Subtraction value register 1813,1823,1833,1843 --- Shiki value register 19 ---switch

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-3-89744 (JP, A) IEICE Technical Report SE 87-138 (December 18, 1987) IEICE Technical Report SS E88-188 (February 19, 1989) IEICE Technical Report SS E90-10 (May 17, 1990) (58) Fields investigated (Int. Cl. ⁷ , DB name) H04L 12/56

Claims (6)

(57) [Claims] 1. A packet communication system for connecting a packet input from an input path to an appropriate output path, wherein a first traffic of a packet input from the input path is monitored, and a first predetermined traffic is monitored. Comparing with a threshold value, and when exceeding a first threshold value, a first monitoring means for issuing a first excess notification; and, based on the first excess notification, A second monitoring means for monitoring traffic of the second threshold, comparing the second threshold with a predetermined second threshold, and issuing a second excess notification when the second threshold is exceeded; Receiving a second excess notification issued by the second monitoring means, a marking means for marking a packet inputted within a predetermined control period in accordance with a predetermined rule, and a mark by the marking means. Attached package Connection means for connecting a packet to the output path. 2. A packet communication system for connecting a packet input from an input path to an appropriate output path, wherein a first traffic of a packet input from the input path is monitored and a predetermined first traffic is monitored. Comparing with a threshold value, and when exceeding a first threshold value, a first monitoring means for issuing a first excess notification; and, based on the first excess notification, A second monitoring means for monitoring traffic of the second threshold, comparing the second threshold with a predetermined second threshold, and issuing a second excess notification when the second threshold is exceeded; Receiving a second excess notification issued by the second monitoring means, a packet discarding means for discarding a packet inputted within a predetermined control period; and a packet discarding means of the inputted packet which is not discarded by the packet discarding means. Connection means for connecting the output packet to the output path. 3. A packet communication system for connecting a packet input from a plurality of input paths to at least one output path, wherein the traffic of the packet input from the input path is measured and the traffic characteristic is determined in advance. Monitoring means for issuing a violation notice in the case of violating, a marking means for marking a packet input within a predetermined control period based on the violation notice issued by the monitoring means, and a mark by the marking means. Connection means for connecting the output packet to the output path. 4. A packet communication system for connecting a packet input from a plurality of input paths to at least one output path, wherein the traffic of the packet input from the input path is measured and the traffic characteristic is determined in advance. Monitoring means for issuing a violation notice in the case of violating, a packet discarding means for discarding a packet input within a predetermined control period based on the violation notice issued by the monitoring means, a packet not discarded by the packet discarding means And a connection means for connecting the output path to the output path. 5. A packet communication system for connecting a packet input from a plurality of input paths to at least one output path, wherein a first traffic of a packet input from the input path is monitored, and a predetermined first packet is monitored. A first monitoring means for comparing with a first threshold value and issuing a first excess notification when exceeding the first threshold value; and the input packet based on the first excess notification. A second monitoring means for monitoring the second traffic of the second device, comparing the second traffic with a predetermined second threshold value, and issuing a second excess notification when the second threshold value is exceeded; Upon receiving a second excess notification issued by the second monitoring means, a marking means for marking a packet input within a predetermined control period in accordance with a predetermined rule; and mark And a connection means for connecting the packet with the symbol to the output path. 6. A packet communication system for connecting a packet input from a plurality of input paths to at least one output path, wherein a first traffic of a packet input from the input path is monitored and a predetermined traffic is monitored. A first monitoring means for comparing with a first threshold value and issuing a first excess notification when exceeding the first threshold value; and the input packet based on the first excess notification. A second monitoring means for monitoring the second traffic of the second device, comparing the second traffic with a predetermined second threshold value, and issuing a second excess notification when the second threshold value is exceeded; Upon receiving a second excess notification issued by the second monitoring means, a packet discarding means for discarding a packet inputted within a predetermined control period; and a packet discarding means among the inputted packets. Connection means for connecting a packet which has not been discarded to the output path.