JPH11136252A - ATM switch and shaping method - Google Patents

Abstract

(57) [Summary] [Problem] To perform shaping for each VP in an ATM switch, dynamically change the transmission traffic volume of each VC according to the reception traffic volume of each VC in the VP, and To improve the transmission efficiency of each VC. SOLUTION: The received traffic volume of each VC in a VP is monitored, and when the received traffic volume of a certain VC exceeds the band allocated to the VC and the traffic stays, the transmission traffic volume of the VC is monitored. To each VC including the VC in the VP in which the VC is set.
Is adjusted so that the sum of the transmission traffic amounts does not exceed the band allocated to the VP. Further, the detection of the traffic stay is performed by monitoring the number of cells of the traffic waiting for transmission registered in the queue assigned to each VC in the output line interface, and when the traffic exceeds a predetermined amount, the traffic stay is detected. Notify the occurrence of

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ATM (Asynchro
More particularly, the present invention relates to an ATM switch having a shaping function of controlling a transmission traffic amount in order to secure communication quality in an output line interface of the ATM switch and a shaping method thereof.

[0002]

2. Description of the Related Art In general, shaping in an ATM switch according to the prior art is performed by using each logical communication path (virtual).
A band is assigned to each path (hereinafter, simply referred to as VP) and each logical communication connection (hereinafter, simply referred to as VC), and control is performed so that traffic is transmitted within the range of the band. Among these, in shaping for each VP, the band allocated to the VP is further fixedly allocated to each VC. For this reason, in the shaping according to the conventional technique, when traffic exceeding a band allocated to a certain VC in a certain VP is received and traffic stays, a band of another VC in the same VP becomes empty. Even if it was, it could not be used.

FIG. 15 shows an ATM according to the present invention and the prior art.
FIG. 16 is a block diagram illustrating an example of an ATM network in which a switch is used; FIG. 16 is a diagram illustrating an example of communication by a shaping method in an ATM switch according to the related art;
FIG. 17 is a diagram for explaining the amount of received / transmitted traffic and the allocated bandwidth for each VC. Hereinafter, the shaping according to the related art will be described with reference to these drawings.
15 and 16, 100 is an ATM switch, 1
01 to 103 are VCs, 130 is a user terminal, 140 is a line, 200 is a public network, 201 is another ATM network, 210 and 230 are VPs, 211 to 213 are reception traffic, 231 to 233 are transmission traffic, 220
Is a queue buffer. FIG. 16 is a diagram showing the concept of shaping in an ATM switch.
Illustration of other constituent circuits included in the switch itself is omitted.

An ATM network using an ATM switch according to the present invention and the prior art includes a plurality of ATM switches 100 connected to each other, as shown in FIG. A terminal 130 is accommodated, and the public network 20 is connected via a line 140.
0 or connected to an ATM network 201 in another district or the like.

[0005] Now, in a network as shown in the figure, a user enters a public network 200 and an ATM switch 100.
A single VP set in a line 140 between the two is borrowed under a digital line contract with a telecommunications carrier, and a plurality of VCs set in the single VP are used. Communication shall be performed.

In FIG. 16, VP 230 indicates a VP borrowed by the user as described above.
Is a VP connected to the VP 230 from within the network. Then, a plurality of VC1s are stored in the VPs 210 and 230.
01 to 103 are set, and VCs 101 to 103 are set.
Are the received traffic VC231-
23 and the transmission traffic 231-2.
33. Then, the queue buffer 22
0 is provided with a queue for temporarily registering traffic before transmitting the received traffic in order to absorb the communication speed between each of the received traffic VCs 211 to 213 and each of the transmitted traffics 231 to 233. It is composed. In the illustrated example, the queue buffer 22
Each queue in 0 is shown as holding traffic 221 to 223.

The VP 230 borrowed by the user described above
FIG. 17 shows an example of the amount of received / transmitted traffic and the allocated bandwidth for each of the VCs 101 to 103 in the table. In FIG. 17, VPI and VCI represent a VP identifier and a VC identifier, respectively, and are used to identify the VP and the VC on the ATM network. In this example, the VPI of the VP 230 shown in FIG. 16 is “0”, and the VCIs of the VCs 101 to 103 set in the VP 230 are “101”, “102”, and “103”, respectively.
It has been. The assigned bandwidth (Tj max) of the entire VP 230 is 10 Mbit / sec, and the VCs 101 to 103
The assigned bandwidths are 5, 3, and 2 Mbit / sec, respectively.

Here, it is assumed that the traffic volumes of the received traffic 211 to 213 input to the VCs 101 to 103 are 1, 7, and 2 Mbit / sec as shown in FIG. In this case, while the traffic volume of the reception traffic 212 of the VC 102 is 7 Mbit / sec, the allocated bandwidth of the transmission traffic 232 is 3 Mbit / sec.
Therefore, the traffic volume that can be transmitted as the transmission traffic 232 of the reception traffic 212 cannot be higher than 3 Mbit / sec. Therefore, the queue in the queue buffer 220
The traffic 222 that is waiting to be transmitted becomes full, and the traffic stays.

On the other hand, while the allocated bandwidth of the VC 101 is 5 Mbit / sec, the traffic volume of the received traffic 211 of the VC 101 is 1 Mbit / sec, and the allocated bandwidth of the VP 230 is 10 Mbit / sec. Only 6 Mbit / s is transmitted per second.

As described above, the ATM switch according to the prior art controls the amount of transmission traffic so that it is within the range of the bandwidth allocated to each VC.
Even if the P has a sufficient bandwidth, it is impossible to increase the amount of transmission traffic of a VC in which traffic is staying.

As a conventional technique relating to this type of ATM switch, for example, a technique described in Japanese Patent Application Laid-Open No. 6-46085 is known.

[0012]

As described above, in the ATM switch according to the prior art, since the bandwidth allocated to each VP is fixedly allocated to each VC, an unused bandwidth is used by another VC. And cannot effectively utilize the line resources.
This is a serious problem particularly in the case of connection to a public network where it is particularly required to use limited line resources effectively.

An object of the present invention is to solve the above-mentioned problems of the prior art, and in shaping for each VP, dynamically change the transmission traffic amount of each VC based on the reception traffic amount of each VC in the VP. Accordingly, an object of the present invention is to provide an ATM switch and a shaping method capable of effectively utilizing a band in a VP and improving transmission efficiency of each VC.

[0014]

According to the present invention, an object of the present invention is to accommodate a plurality of lines and have a shaping function for controlling the amount of transmission traffic transmitted from the output line interface to the line. In an ATM switch that performs shaping for each VP in which a queue is set, a queue buffer having a queue for each VC that temporarily holds received data until transmission, and a control unit that controls storage of data in the queue A shaping definition information table used for controlling the transmission traffic volume of the VP, and a transmission unit for controlling data reading and transmission from a queue buffer based on an instruction from the control unit and the contents of the shaping definition information table. The control unit is configured to determine an amount of received traffic received through an input line interface; Monitor the staying traffic staying in the queue buffer, and when the amount of staying traffic of a certain VC exceeds a predetermined amount, notify the sending unit of the staying traffic, the sending unit, Achieved by temporarily increasing the transmission traffic volume of the VC to the extent that the sum of the transmission traffic volume of each VC including the VC to which the VC belongs including the VC does not exceed the traffic volume allocated to the VP. Is done.

According to the present invention, by providing the above-described configuration, the amount of transmission traffic and the amount of reception traffic of each VC in the VP are monitored, and the amount of reception traffic of a certain VC is assigned to the band allocated to the VC. If the total traffic volume including the relevant VC of the VP at that time is less than the bandwidth allocated to the VP, the traffic does not exceed the bandwidth allocated to the VP. Since the transmission traffic volume can be increased in accordance with the reception traffic volume of the VC, it is possible to eliminate the stagnation of the traffic of the VC. Then, when the amount of received traffic decreases, the amount of transmitted traffic can be restored.

According to the present invention, since the shaping is performed as described above, even when the communication is performed by borrowing a VP to which a certain band is allocated from a communication carrier, the amount of transmission traffic of each VC in the VP is determined. Can be dynamically changed according to the amount of received traffic, whereby the limited VP band can be more effectively utilized.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of an ATM switch and a shaping method according to the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of an ATM switch according to an embodiment of the present invention, FIG. 2 is a diagram for explaining the contents of a transfer destination table, and FIG. Illustration to explain, FIG.
Is a diagram for explaining the contents of the shaping definition information table,
FIG. 5 is a flowchart illustrating a processing operation for adjusting the amount of transmission traffic of each VC in the VP. FIG. 6 is a diagram illustrating the number of cells in the queue waiting for transmission in each queue in the queue buffer in the queue buffer. 9 is a flowchart illustrating a processing operation for notifying occurrence and cancellation to a transmission unit. In FIG. 1, 110 is an input line interface unit, 111 is an input port, 112 is a receiving unit, 113 is a transfer unit, 114 is a transfer destination table, 120 is an output line interface unit, 121 is a receiving unit, and 122 is a control unit. , 1
23 is a queue table to which traffic is assigned, and 124
Is a queue buffer, 125 is a queue, 126 is a transmission unit,
127 is a shaping definition information table, 128 is a transmission port, and the other symbols are the same as those in FIGS.

FIG. 1 shows an AT according to an embodiment of the present invention.
The M switch 100 includes an input-side line interface unit 11
0 and an output-side line interface unit 120 having a shaping function. The input-side line interface unit 110 includes an input port 111 connected to the user terminal 130 and another ATM switch, and an input port 111.
, A transfer destination table 114 having transfer destination information of received data, and a transfer unit 113 for transferring data based on the contents of the transfer destination table 114. Further, the output-side line interface unit 120 is connected to the input-side line interface unit 110.
Receiving section 121 for receiving data from transfer section 113
And a queue buffer 124 having a queue 125 for each VC that temporarily holds data until the data is transmitted.
And a reception traffic assignment destination queue table 123 for determining a traffic assignment destination queue, a control unit 122 for controlling storage of data in a queue based on the table, and a shaping definition used for controlling a VP transmission traffic amount Information table 127 and control unit 122
A transmission unit 126 for controlling the reading and transmission of data from the queue buffer 124 based on an instruction from the controller and the contents of the shaping definition information table 127;
8 is provided.

ATM switch 1 configured as described above
At 00, traffic input from the user terminal 130 through the input port 111 of the input-side line interface unit 110 is received by the receiving unit 112, and then sent to the transfer unit 113. The transfer unit 113 refers to the transfer destination table 114 and transfers the traffic to the output-side line interface unit 120 corresponding to the output port. As shown in FIG. 2, the forwarding destination table 114 indicates to which output port the traffic input to the input port is output, by the input port identification number, VPI,
The VCI and the output port number are stored in association with each other.

The traffic transferred to the output line interface 120 is received by the receiving unit 121.
Then, the received traffic is transmitted to the reception traffic assignment destination queue table 123 by the control unit 122.
, And is temporarily stored in the queue buffer 124 in the queue 125 defined for each VC according to the VP and VC values of each traffic. As shown in FIG. 3, the reception traffic assignment destination queue table 123 stores the numbers of the queues 125 defined by the VP and VC values of each traffic and the port numbers on the input side in association with each other. .

Each queue 125 in the queue buffer 124
Are registered by the transmission unit 126 and transmitted from the output port 128 to the line 140. At this time, the transmission unit 126 refers to the shaping definition information table 127, and controls the transmission traffic volume of each VP so as not to exceed the value of the allocated bandwidth defined in the table. Shaping definition information table 12
As shown in FIG. 4, the value of the assigned bandwidth assigned to each VP and VC set in the transmission port is stored in 7.

Next, with reference to FIG. 5, a description will be given of a processing operation for adjusting the transmission traffic amount of each VC in the VP in the transmission section 126 of the output line interface.

(1) The transmission unit 126 periodically checks whether there is a notification from the control unit 122 that traffic of each VC in the VP has been generated and resolved, and terminates the process if there is no notification ( Steps 501 and 502).

(2) In step 502, when there is a notification that the traffic has accumulated or has been eliminated, the transmitting unit 1
26 receives the received traffic volume (Tj rec) of the VC from the control unit 122 (step 503).

(3) Next, the transmitting unit 126 checks whether the received notification indicates the occurrence of traffic stagnation,
It is determined whether or not the stay has been canceled (step 50).
4, 505).

(4) When the notification of the occurrence of the stagnation is detected in step 505, the transmitting unit 126 sets the total transmission traffic amount (S) of the upper VP (S) obtained by the equation (1).
i) and the assigned bandwidth (Si max) of the VP are compared under the conditions of the equation (2), and it is determined whether or not both match (steps 507 and 508).

[0028]

(Equation 1)

Here, Tj is the transmission traffic amount of each VC included in the VP, and n is the number of VCs included in the VP.

[0030]

(Equation 2)

(5) In step 508, VP (S)
If the transmission traffic amount (Si) of the VP does not match the allocated bandwidth (Si max) of the VP, the transmission unit 126
The transmission traffic amount (Tj) of the VC in which the stagnation has occurred is increased within a range not exceeding the allocated band (Si max) of the VP. In this case, the transmission traffic amount (Tj new) after the adjustment of the VC can be obtained by the equation shown in Expression 4 (Step 509).

[0032]

(Equation 4)

(6) In step 508, VP (S)
If the transmission traffic amount (Si) of the corresponding VP and the assigned bandwidth (Si max) of the VP match, it means that the VP is transmitting with the full assigned bandwidth, and usually the transmission traffic amount ( Tj) cannot be adjusted, but other VCs in this VP are added to each VC.
Since there is a possibility that a VC (U) in which the transmission traffic amount (Tk) has been increased beyond the assigned bandwidth (Tk max) for each of the existing VCs already exists, a VC that satisfies the condition of the expression shown in Expression 5 is obtained. By checking whether or not such a VC exists, it is checked whether or not such a VC exists (step 51).
0, 511).

[0034]

(Equation 5)

(7) As a result of the check in step 511, the transmission traffic amount exceeding the allocated bandwidth (Tk max)
If it is determined that there is a VC (U) for which (Tk) has been increased, the transmitting unit 126 determines that each VC in the VP, including the VC,
It is determined that the transmission traffic volume of C needs to be adjusted, and the current transmission traffic volume (Tj) of the VC and the transmission traffic volume (Uv) of the VC whose transmission traffic volume has already been increased beyond the allocated bandwidth. Is redistributed according to the value of the allocated bandwidth of each VC. In this case, the transmission traffic amount (Tj new) after the adjustment of the VC can be obtained by the equation shown in Expression 6 (Step 512).

[0036]

(Equation 6)

(8) Also, in step 505, if the received notification indicates that the stay of traffic has been eliminated, the transmission unit 126 reduces the transmission traffic amount (Tj) of the VC. In this case, the transmission traffic amount (Tj new) after the adjustment of the VC can be obtained by the equation shown in Expression 3 (Step 506).

[0038]

(Equation 3)

Next, referring to the flow shown in FIG. 6, the control unit 122 of the output-side line interface monitors the number of cells in the queue 125 of the queue 125 for each VC in the queue buffer 124 and waits for transmission. And a processing operation for notifying the transmission unit 126 of the cancellation.

(1) The control unit 122 controls the queue buffer 1
24, the number of cells waiting to be transmitted registered in the queue 125 for each VC is periodically checked, and the number of cells waiting to be transmitted (Cj) of the VC and the boundary of the retention detection preset for the VC are set. The value is compared with the number of cells (Cj max), and Cj ≧
It is checked whether or not Cj max has been reached (steps 601 and 602).

(2) By checking in step 602, Cj
If the condition of ≧ Cj max is satisfied, that is, if it is determined that a traffic stagnation has occurred in the VC, the control unit 122 determines whether or not the occurrence of the stagnation has already been notified to the transmission unit 126. And if you have been notified,
The processing ends without performing any processing (step 603,
604).

(3) If it is determined in step 604 that the notification of the occurrence of the stay has not been received, the control unit 122 acquires the received traffic volume (Tj rec) of the VC, and
And the amount of traffic received by the VC (Tj re
c) is notified (steps 605 and 606).

(4) In the check of step 602, Cj
If the condition of ≧ Cj max is not satisfied, that is,
When it is determined that no traffic has accumulated in the VC, the control unit 122 determines whether or not traffic has accumulated in the queue of the VC at the time of the previous check. If not, the process ends without performing any process (steps 607 and 60).
8).

(5) If it is determined in step 608 that a traffic stay has occurred at the time of the previous check, the control unit 122 notifies the transmitting unit 126 of the cancellation of the stay (step 609).

The ATM switch according to the embodiment of the present invention can dynamically change the transmission traffic volume of each VC in the VP according to the reception traffic volume by performing the above-described control. Therefore V
The band allocated to P can be effectively used, and transmission efficiency can be improved.

FIG. 7 is a diagram specifically illustrating an example of a shaping control method performed in the output-side line interface unit 120 in FIG. 1, and FIG.
FIG. 9 is a diagram showing a transmission traffic amount (Tj new) after traffic adjustment. Hereinafter, the actual shaping operation in the ATM switch performing the above-described processing operation will be specifically described with reference to these drawings.

Here, as described in the prior art,
VP (VPI =
Each of the VCs 101 to 10 when performing “0”) shaping
The control of the transmission traffic amount of No. 3 will be described. The codes given to VP, VC and traffic among the codes shown in FIG. 7 are the same as those in FIG. 16, and the others are the same as those in FIG.

The control unit 122 monitors the amount of received traffic 211 to 213 of the VCs 101 to 103, and
The amount of traffic waiting for transmission 221 to 223 registered in the queue for each VC in the queue buffer 124 is also monitored.

Now, at a certain point, the queue of the VC 102 is full of traffic 222 waiting for transmission,
It is assumed that traffic has accumulated. Control unit 12
2 is the amount of received traffic 212 of the VC 102 (Tj r
ec). At this time, it is assumed that the received traffic volume of each of the VCs 101 to 103 has a value as shown in FIG. Accordingly, the control unit 122 determines that the queue of the VC 102 is full and that the volume of the received traffic 212
(Tj rec) is notified to the transmitting unit 126.

The transmitting unit 126 monitors and controls the amount of transmission traffic, and the transmission traffic amount (Si) of the entire VP at the time of receiving the above-mentioned notification and the shaping definition information table 127 (the definition contents are shown in FIG. 4). Assigned to the VP defined in the above)
(Si max). As a result, it is assumed that it is found that the transmission traffic amount (Si) is only 7 Mbit / sec for the bandwidth (Si max) of 10 Mbit / sec allocated to the VP.

The transmitting section 126 controls the VC within a range not exceeding 10 Mbit / sec.
102 by adjusting the amount (Tj) of the outgoing traffic 232,
For example, as shown in FIG.
(Tj new) state (Tj new can be calculated by the equation shown in Equation 4 as described above). The control unit 540 decreases the amount (Tj) of the transmission traffic 232 when the corresponding queue is no longer full (elimination of the traffic stagnation) (T in this case).
j new can be calculated by the equation shown in Equation 3).

According to the embodiment of the present invention, the above-described control allows the bandwidth allocated to the entire VP to be effectively utilized, and at the same time, the transmission traffic 232 of the VC 102.
Can be transmitted more efficiently.

FIG. 10 is a diagram specifically illustrating another example of the shaping control method performed in the output side line interface unit 120 in FIG. 1, and FIG. 11 is a diagram illustrating the received traffic amount (Tj rec ), And FIG. 12 shows the transmission traffic amount (Tj n) after the traffic adjustment.
ew). Hereinafter, with reference to these drawings, another example of the actual shaping operation in the ATM switch that performs the above-described processing operation will be specifically described.

The example shown in FIG. 10 shows the shaping control performed in the output-side line interface unit in the same manner as described with reference to FIG.
02 queue is full and the traffic of the VC 102 is stagnated.
It is assumed that the amount (Tj) of the transmission traffic 232 of 102 has already been increased.

The control unit 122 monitors the amount of the received traffic 211 to 213 of the VCs 101 to 103, and
The amount of traffic waiting for transmission 221 to 223 registered in the queue for each VC in the queue buffer 124 is also monitored.

At some point, the queue of the VC 102 is full, so that the amount of transmission traffic 232 is
It is assumed that (Tj) is increased to eliminate the stagnation of traffic. In this state, it is assumed that the queue of the VC 101 is full and traffic is stagnated.
In this case, the control unit 122 checks the amount of the received traffic 211.

As a result, assuming that the received traffic volume (Tj rec) of each VC at this point has a value as shown in FIG. 11, the control unit 122 determines that the queue corresponding to the VC 101 is full. , The amount of received traffic 231 (Tj rec) in FIG.

The transmission unit 126 transmits the transmission traffic amounts 232 and 233 (Tj) of the VCs other than the VC 101 at the time when the above-described notification is received from the control unit 122 and the shaping definition information table 127 (the definition contents are shown in FIG. 4). Allocated band (Tj m) defined in the
ax) to check whether there is any VC whose transmission traffic volume has been increased beyond the allocated bandwidth of each VC. As a result, when the transmission traffic amount before the current adjustment of each VC is the transmission traffic amount as shown in FIG. 12, the transmitting unit 126 determines that the amount of the transmission traffic 232 of the VC 102 exceeds the allocated band. Can be detected.

Therefore, the transmitting unit 126 determines the amount of the transmission traffic 231 of the VC 101 (Tj = 2 Mbit / sec),
The amount of the transmission traffic 232 of the VC 102 (Tj = 6 Mbit / sec) is summed (8 Mbit / sec), and the sum of the transmission traffic is assigned to the allocated bandwidth (Tj
max = 5 Mbit / s) and the allocated bandwidth of the VC 102 (T
j max = 3 Mbit / sec) and (8 Mbit / sec)
Redistribution is performed according to the ratio of each VC to the total allocated bandwidth, and the adjusted transmission traffic amount (Tj new) as shown in FIG. 12 is obtained.

As a result, the VP band is optimally allocated according to the amount of received traffic of each VC.

FIG. 13 shows the queue buffer 12 of the shaping control performed in the output line interface unit.
4 is a diagram for explaining a method of detecting traffic stagnation in a queue for each VC in FIG. 4. FIG. 14 is a diagram showing the contents of a traffic stagnation detection information table storing information for detecting traffic stagnation. With reference to these figures, a method for detecting the stagnation of traffic in the ATM switch performing the above-described processing operation will be described.

The control unit 122 determines the amount Cj (actually, the number of cells constituting traffic) of the transmission waiting traffic 221 to 223 registered in each of the VCs 101 to 103 in the queue buffer 123, The number of stay detection cells Cj max for each VC defined in the traffic stay detection information table as shown in FIG. 14 provided in the queue table 123 is compared. As a result, if the amount of traffic 222 waiting to be transmitted in the queue of the VC 102 at a certain point in time is equal to or greater than 60 cells, and this has not been notified to the transmitting unit 126, the control unit 122 generates a traffic stagnation in the VC 102. It is determined that the traffic has been received, and the amount (Tj rec) of the received traffic 212 of the VC 102 is acquired, and the transmission unit 126 is notified of the occurrence of traffic stagnation in the VC 102 and the amount (Tj rec) of the received traffic 212 of the VC 102 .

When the amount (Cj) of the traffic waiting for transmission 222 in the queue of the VC 102 has decreased to less than 60 cells, the control unit 122 determines that the traffic has been eliminated, and the transmission unit 126 determines that the traffic has not accumulated. Notify cancellation.

[0064]

As described above, according to the present invention, V
The bandwidth allocated to each P can be effectively used, the transmission efficiency of the traffic of the VC in the VP can be improved, and the line resources can be used effectively.

[Brief description of the drawings]

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

FIG. 2 is a diagram illustrating the contents of a transfer destination table that defines a transfer destination of a received cell.

FIG. 3 is a diagram illustrating the contents of a table that defines a reception traffic allocation destination queue.

FIG. 4 is a diagram illustrating the contents of a shaping definition information table.

FIG. 5 is a flowchart illustrating a processing operation for adjusting the amount of transmission traffic of each VC in the VP.

FIG. 6 is a flowchart illustrating a processing operation for monitoring the number of cells of traffic waiting for transmission of a queue for each VC in a queue buffer, and notifying a transmission unit of occurrence and elimination of a stay;

FIG. 7 is a diagram specifically illustrating an example of a shaping control method performed in the output-side line interface unit in FIG. 1;

FIG. 8 shows an example of each V at a certain point in the example shown in FIG.
It is a figure which shows the received traffic amount (Tj rec) of C.

FIG. 9 is a diagram illustrating a transmission traffic amount (Tj new) after traffic adjustment in the example illustrated in FIG. 7;

10 is a diagram specifically illustrating another example of a shaping control method performed in the output-side line interface unit in FIG. 1. FIG.

11 is a diagram showing a received traffic amount (Tjrec) of each VC at a certain point in the example shown in FIG.

FIG. 12 is a diagram showing a transmission traffic amount (Tj new) after traffic adjustment in the example shown in FIG. 10;

FIG. 13 is a diagram specifically illustrating an example of a method of detecting a stagnation of traffic in a queue for each VC in a queue buffer.

FIG. 14 is a diagram showing the contents of a traffic stay detection information table storing information for detecting traffic stay.

FIG. 15 is a block diagram showing an example of an ATM network using an ATM switch according to the present invention and the prior art.

FIG. 16 is a diagram illustrating an example of communication by a shaping method in an ATM switch according to the related art.

FIG. 17 is a diagram illustrating the amount of received / transmitted traffic and the allocated bandwidth for each VC.

[Explanation of symbols]

 Reference Signs List 100 ATM switch 101 to 103 VC 110 Input-side line interface unit 111 Input port 112, 121 Receiving unit 113 Transfer unit 114 Transfer destination table 120 Output-side line interface unit 122 Control unit 123 Traffic assignment destination queue table 124 Queue buffer 125 Queue 126 Transmission Part 127 shaping definition information table 128 transmission port 130 user terminal 140 line 200 public network 201 other ATM network 210, 230 VP 211-213 reception traffic 231-233 transmission traffic 220 queue buffer

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Norihiro Niwa 810 Shimoimaizumi, Ebina-shi, Kanagawa Prefecture In-house Systems Division, Hitachi, Ltd. Address Hitachi Software Engineering Co., Ltd.

Claims (3)

[Claims] 1. A shaping function for accommodating a plurality of lines and controlling an amount of transmission traffic transmitted from an output line interface to the line, wherein shaping is performed for each logical communication path in which a plurality of logical communication connections are set. A queue buffer having a queue for each logical communication connection that temporarily holds received data until it is transmitted, a control unit for controlling storage of the data in the queue, and transmission traffic of the logical communication path A shaping definition information table used for controlling the amount, reading data from the queue buffer based on an instruction from the control unit and the contents of the shaping definition information table, a transmission unit that controls transmission, the control unit,
The amount of received traffic being received through the input side line interface and the amount of staying traffic staying in the queue buffer are monitored. When there is traffic, the transmitting unit notifies the transmitting unit that the traffic has stayed. AT which temporarily increases the transmission traffic volume of the logical communication connection within a range not exceeding the traffic volume allocated to the communication path.
M switch. 2. A shaping function for accommodating a plurality of lines and controlling an amount of transmission traffic transmitted from the output line interface to the line, wherein shaping is performed for each logical communication path in which a plurality of logical communication connections are set. In the shaping method of the ATM switch to be performed, the amount of received traffic received through the input-side line interface and the amount of received traffic of a certain logical communication connection are reduced by the amount of transmitted traffic allocated to the logical communication connection in advance. More than
It monitors whether or not the traffic stays in the output line interface, and when the amount of the staying traffic of a certain logical communication connection exceeds a predetermined amount, the logical communication to which the logical communication connection belongs. As long as the sum of the transmission traffic volume of each logical communication connection including the logical communication connection on the route does not exceed the bandwidth allocated to the logical communication route, the bandwidth to which the transmission traffic volume of the logical communication connection is allocated A shaping method characterized by temporarily increasing the value beyond the limit. 3. A method for monitoring whether or not a stagnation of traffic has occurred is performed by a queue temporarily registered for each logical communication connection in an output line interface until received traffic is transmitted. When the amount of traffic registered and waiting for transmission exceeds the number of cells defined in advance for each logical communication connection, it is determined that a traffic stagnation has occurred. Item 2. The shaping method according to Item 2.