JP3479927B2 - Traffic control method and device - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an ATM (Asynchronous).
nous Transfer Mode) Regarding traffic control performed in a network, especially usage parameter control (UPC: User)
Parameter Control) and network usage parameter control (NPC: Network Parameter Control)
And traffic shaping methods and apparatus.

[0002] In traffic control, for example, a malicious user who detects a violation of a traffic volume with respect to a negotiated parameter and takes a predetermined measure to adversely affect the QoS (Quality of Service) of another connection. Cell delay fluctuations (CDV: Cell Delay V) that occur in the ATM device and UPC and NPC that protect users and networks from interference, etc.
traffic shaping, which reduces ariation) and shapes the traffic characteristics into a desired shape.

In traffic control in an ATM network, it is possible to reduce the amount of memory required by the UPC (NPC) and the shaper, reduce the amount of software management memory and the parameter setting time, and reduce the circuit scale. Is required.

[0004]

2. Description of the Related Art First, the roles of UPC and NPC and a shaper will be described. In ATM communication, information to be communicated is divided into fixed-length cell units and asynchronously transferred. At this time, the user declares the transfer amount of information to the network side, and the network side performs accommodation design, Give the user permission to assign. That is, the traffic negotiate (contract). In this case, if one user transfers information in excess of the contracted amount, there is a possibility that other users may be adversely affected by cell loss or the like.

Therefore, at the entrance of the network, UPC and N
A PC is arranged to monitor information transmitted by a user or another network, and if there is a violation, the information is discarded. However, due to the CDV generated in the user device, etc., the U
In order to avoid the information being discarded by the PC (NPC), some violation is allowed. Therefore, UPC
A shaper is arranged in the latter stage of (NPC) to reduce the CDV.

FIG. 6 shows UPC and NP in an ATM network.
C, which shows the position of the shaper,
U is UPC, N is NPC, and S is a shaper.

As shown in FIG. 6, a user equipment is a subscriber line terminating device SLT (Su) provided in an ATM network through a user network interface UNI (User Network Interface).
bscriver Line Terminater) and other networks are connected to the network node interface NNI (Ne
twork Node Interface) and is connected to the cross-connect device XC. The subscriber terminating device SLT, via the cross-connect device XC, sends another cross-connect device XC.
Connected to.

In the subscriber line terminating device SLT, a UPC (U) is provided on the user device side, and a shaper (S) is provided at the subsequent stage. In the cross-connect device XC, NPC is installed on the other network side.
(N) is provided, and the shaper (S) is provided at the subsequent stage.

The UPC monitors whether or not the traffic characteristics of the cell flow sent from the user of the ATM service comply with the parameters contracted with the user, and controls the cell flow as necessary. Then, for example, the discarding process is performed on the cell that violates the contract. Violation determination in this case is performed by a virtual scheduling algorithm (VSA) or
Leaky Bucke Algorithm (LBA: Leacky bucke
t Algorithm). These two algorithms are referred to as ITU-TI. 371.

The NPC also monitors whether or not the traffic characteristics of the cell flow transmitted from another network comply with the contracted parameters, and controls the cell flow as necessary. The operation of NPC in this case is similar to that in UPC. In the following, the case of UPC will be mainly described, but the same applies to the case of NPC.

FIG. 7 shows an example of the UPC algorithm (virtual scheduling algorithm). In FIG. 7, the minimum cell interval T, the CDV allowable value τ
Is a parameter that is set as a result of negotiation. The theoretical cell arrival time TAT and cell arrival time ta are
It is a parameter for calculation.

The cell flow defined by the cell interval T is usually
The cells always arrive at T intervals. Therefore, based on the cell arriving at the time ta, the time at which the cell should arrive next is theoretically defined by ta + T. The time at which this cell should arrive is called the theoretical cell arrival time TAT.

When the actual arrival time ta of the cell arrives later than the theoretically specified time (TAT≤t
In a), the TAT is updated after determining that the cell is a conforming cell and changing the TAT to the current time.

When the actual arrival time ta of the cell arrives earlier than the theoretically specified time (TAT> t
Although a) means that the cell violates the contract, it is not immediately judged as a non-conforming cell that violates the contract,
The difference between the theoretical cell arrival time TAT and the cell arrival time ta (TAT-ta: indicates how much the arriving cell violates the contract) and the CDV allowable value τ are compared to determine whether they match. Or judge nonconformity.

That is, when TAT-ta is larger than τ, it is determined that the cell is a non-conforming cell, discarding processing is performed, and T
If AT-ta is τ or less, you are in violation of the contract,
The TAT is updated by determining that the cell is a conforming cell within the allowable range.

Next, the shaper will be described. The shaper has a function of reducing the CDV contained in the cell flow,
It is provided after UPC.

The shaper buffers cells that have violated the contract based on the CDV and outputs the cells at a desired time. The cell output time is determined using an algorithm such as a virtual scheduling algorithm or leaky bucket algorithm. If the cell output time conflicts with other cells, the FIFO (First-In First-O)
ut) Output competition is controlled by discipline, and the cells in the same connection are output without changing the order.

FIG. 8 shows an example of the shaping algorithm (virtual scheduling algorithm). In FIG. 8, the minimum cell interval T and the CDV residual value τ are parameters set as a result of the negotiation. Theoretical cell transmission time TET, cell output time Tou
t and cell arrival time ta are parameters for calculation.

The cell flow defined by the cell spacing T is usually
The cells always arrive at T intervals. Therefore, based on the cell arriving at time ta, the time at which the cell should arrive next is theoretically defined by ta + T. The arrival time of this cell is called the theoretical cell arrival time TAT. In the shaper,
Basically, the cell is controlled to be output at this time, so that it is also called theoretical transmission time TET.

In fact, when the cell arrival time ta arrives later than the theoretically specified time (TAT≤
ta) determines that the cell is a conforming cell, changes the TET to the current time, and then updates the TET. Also, the cell outputs at the current time.

In fact, when the arrival time ta of the cell arrives earlier than the theoretically specified time (TAT>
ta) means that the cell violates the contract, but it is not immediately judged as a nonconforming cell that violates the contract, and the difference between the theoretical cell transmission time TET and the cell arrival time ta (TET- ta: indicating how much the arriving cell violates the contract) and the CDV residual value τ are compared to determine conformity or nonconformity.

When TET-ta is larger than τ, it is determined that the cell is a non-conforming cell, shaping is performed, and TET-τ.
Output at the time. If TET-ta is τ or less, the contract is violated, but the cell is output at the current time as a conforming cell within the allowable range and TET is updated.

[0023]

[Problems to be Solved by the Invention] Conventionally, UPC (NP
C) and the shaper have a very large amount of memory required for storing parameters and cell data and a very large hardware scale.
There were various restrictions in attaching external memory.

However, in order to realize full-scale multimedia technology in the future, there is a demand for downsizing, low power consumption, and low cost of ATM-related devices. The present invention is intended to solve such a problem of the conventional art, and reduces the memory amount, the hardware amount, and the management memory amount of software required for the UPC (NPC) and the shaper. To do the
An object is to provide a traffic control method and apparatus.

[0025]

In the present invention, the UP
Of the parameters used in C (NPC), the minimum cell spacing and the parameters used in the traffic shaper
The minimum cell spacing is represented by one common parameter. Then, an integrated UPC (NPC) / shaper algorithm is provided for performing shaping immediately after the violation determination.

Among the traffic monitoring parameters used in UPC (NPC), the minimum cell interval Tu and among the parameters used in the traffic shaper, the minimum cell interval T
The relation with s must always be Tu ≧ Ts. If this relationship is not maintained, in the shaper,
The input traffic may be larger than the output traffic, causing the shaper to overflow the buffer or discarding any cells.
If Tu = Ts, such a problem cannot occur and U
The parameters of the PC and the shaper can be expressed by one common parameter, and the required memory amount can be reduced.

As described above, in the present invention, the UPC
The minimum cell interval of the parameters used in (NPC) and the minimum cell interval of the parameters used in the shaper are expressed by one common parameter, which is required in UPC (NPC) and the shaper. It is possible to reduce the memory amount, the hardware amount, and the software management memory amount.

The specific means for solving the problems of the present invention will be described below.

(1) In traffic control performed in an ATM network in which information to be communicated is divided into fixed-length cell units and asynchronously transferred, a violation of the traffic volume with respect to negotiated parameters is detected and a prescribed action is taken. Among the parameters used for traffic monitoring in UPC or NPC control to be performed, the minimum cell interval T obtained from the negotiated cell rate and the parameter used in control of the shaper that reduces cell delay fluctuations and shapes the traffic characteristics into a desired shape. Among them, the minimum cell interval T calculated from the negotiated cell rate is expressed by one common parameter, and by performing the above two types of control, the input ATM cell and the previously input ATM cell of the same connection are The interval between and is stored in the storage device, nego shade When the minimum cell interval calculated from the traffic volume is violated and the threshold stored in the storage device is exceeded, the cell is not passed, and when it is within the threshold, the cell output time Is adjusted and output at a desired time, and when the minimum cell interval is not violated, the cell is passed through as it is.

(2) In the case of (1), a mode for performing UPC or NPC control and a mode for controlling the shaper are provided, and either one of the controls can be selected and performed by mode switching.

(3) The traffic control method in the case of (1) or (2) is applied when a virtual scheduling algorithm is used as a traffic monitoring method in UPC or NPC control and an output time calculation method in shaper control.

(4) The traffic control method in the case of (1) or (2) is applied when a leaky bucket algorithm is used as a traffic monitoring method in UPC or NPC control and an output time calculation method in shaper control.

(5) In the case of (1), the traffic control device is negotiated for each cell type, and the cell detection section 3 for reading the control data described in the header section of the input cell to detect the cell type. Using the parameter storage memory 6 for storing the traffic parameters and the traffic parameters stored in the parameter storage memory 6, a traffic amount violation for the input cell is detected according to a predetermined algorithm for each cell type. Arithmetic unit 4 for calculating output time, arithmetic storage device 7 for storing arithmetic parameters used for arithmetic operation in arithmetic unit 4, and cell data storage memory device 1 for storing input cell data.
And a memory controller 5 that manages the address of the cell data stored in the cell data storage device 1 based on the cell output time input from the arithmetic unit 4, and the address management of the cell data in the memory controller 5. Memory control storage device 8 for storing data necessary for memory cell storage device 1 and cell data storage storage device 1 according to the output address of the memory control unit 5.
And an output control unit 2 for outputting the data of the corresponding cell at the obtained output time.

(6) In the case of (5), the parameter storage memory device 6, the arithmetic storage device 7, the cell data storage memory device 1 and the memory control memory device 8 are integrated into an LSI that accommodates the traffic control device. Built-in.

(7) In the case of (5), the parameter storage memory device 6, the arithmetic storage device 7, the cell data storage memory device 1 and the memory control memory device 8 are externally attached to the traffic control device.

[0036]

1 shows an embodiment (1) of the present invention, in which a traffic monitoring method in a UPC (NPC) and an output time calculation method in a traffic shaper are represented by a virtual scheduling algorithm ( VSA) is applied to the embodiment.

In FIG. 1, the minimum cell interval T (UPC /
NPC and shaper are common), CDV allowable value τu, and CDV residual value τs are parameters set as a result of nego-shading. Theoretical cell arrival time TAT, cell output time T
out and cell arrival time ta are parameters for calculation.

In this embodiment, UPC (NPC)
The minimum cell interval T used in step 1 and the minimum cell interval T used in the shaper are expressed by common parameters, and after the violation judgment,
Immediately reduce CDV.

The cell flow defined by the cell interval T is usually
The cells always arrive at T intervals. Therefore, based on the cell arriving at the time ta, the time at which the cell should arrive next is theoretically defined by ta + T. The time of the cell which should arrive is called the theoretical cell arrival time TAT.

If the actual arrival time ta of the cell is later than the theoretically specified time (TAT ≦ ta),
The TAT is updated after determining that the cell is a conforming cell and changing the TAT to the current time. Also, the cell outputs at the current time.

If the actual arrival time ta of the cell is earlier than the theoretically specified time (TAT> ta),
This means that the cell violates the contract, but the user does not immediately judge that the cell is a nonconforming cell that violates the contract, and the difference between the theoretical cell arrival time TAT and the cell arrival time ta (TAT-ta: It shows the degree to which the arriving cell violates the contract) and the magnitude relationship of the CDV allowable value τu, and determines conformity or nonconformity.

When TAT-ta is larger than τu, it is determined that the cell is a non-conforming cell and the discarding process is performed. Also TA
If T-ta is equal to or less than τu, the contract is violated, but the cell is determined to be a conforming cell within the allowable range, and shaping (reduction of CDV) is performed without performing the discarding process.

When performing shaping, TAT-ta
And CDV residual value τs are compared, and TAT-ta is τs
When it is larger, C is obtained by (TAT-ta) -τs.
DV is reduced, a cell is output at time TAT-τs, and T
When AT-ta is τs or less, the cell is output at the current time ta and TAT is updated.

Conventionally, the parameters that need to be stored in the storage device are the minimum cell interval T, the CDV allowable value τu, and the theoretical cell arrival time TAT in the case of UPC (NPC), and the minimum cell interval in the case of the shaper. T, CDV residual value τ
s, the theoretical cell transmission time TET.

On the other hand, according to the present embodiment, the parameters that need to be stored in the storage device are the minimum cell interval T (UPC / NP) in the UPC (NPC) and the shaper.
C, common shaper), CDV allowable value τu, CDV residual value τs, theoretical cell arrival time TAT (common to theoretical cell transmission time TET), and the number of parameters is reduced by two.

FIG. 2 shows an example of the required memory amount in the case of the embodiment (1), and shows an example in which the number of connections accommodated is 256 connections. According to this embodiment, the memory amount is 1 compared to the conventional case.
4K bits are reduced.

FIG. 3 shows an embodiment (2) of the present invention, in which a traffic monitoring method in UPC (NPC) and an output time calculation method in traffic shaper are applied to a leaky bucket algorithm (LBA). The embodiment in the case of doing is shown.

In FIG. 3, the minimum cell interval T (UPC /
NPC and shaper are common), CDV allowable value τu, and CDV residual value τs are parameters set as a result of nego-shading. The LB counter value X, the LB counter provisional calculation value X ′, the cell output time Tout, the previous cell arrival time LT, and the cell arrival time ta are parameters for calculation.

In this embodiment, UPC (NPC)
The minimum cell interval T used in step 1 and the minimum cell interval T used in the shaper are expressed by common parameters, and after the violation judgment,
Immediately reduce CDV.

When the cell arrives at the time ta, the difference (LT-ta: arrival cell interval) from the time LT of the cell that arrived one time before is subtracted from the LB counter value.

When the calculated value X'is less than 0, it is determined that the cell is compatible, the calculated value X'is changed to 0, and then the LB counter value X and the previous cell arrival time LT are updated. Also, the cell outputs at the current time.

If the calculated value X'is larger than 0, it means that the cell is a cell that violates the contract, but the user does not immediately judge that the cell is a nonconforming cell that violates the contract. Matching or non-matching is determined by comparing the magnitude relationship between the calculated value and the CDV allowable value τu.

When the calculated value X'is larger than τu,
The cell is determined to be a non-conforming cell and discarded processing is performed. When the calculated value X ′ is τu or less, the contract is violated, but it is determined as a conforming cell within the allowable range, and the discard processing is not performed,
Performs shaping (reduces CDV).

When performing shaping, the calculated values X'and C
When the calculated value X ′ is larger than τs by comparing with the DV residual value τs, the CDV is reduced by X′−τs, the cell is output at time ta + (X′−τs), and the calculated value is calculated. When X ′ is equal to or less than τs, the cell is output at the time ta and the previous cell arrival time LT and the LB counter value X are updated.

Conventionally, the parameters that need to be stored in the storage device are the minimum cell interval T, the CDV allowable value τu, the LB counter value X, the previous cell arrival time LT in the case of UPC, and the minimum cell in the case of the shaper. Interval T, CDV residual value τ
s, the LB counter value X, and the previous cell arrival time LT.

On the other hand, according to the present embodiment, the parameters that need to be stored in the storage device are the minimum cell interval T (UPC / NP) in the UPC (NPC) and the shaper.
C, shaper common), CDV allowable value τu, CDV residual value τs, LB counter value X (UPC, shaper common), previous cell arrival time LT (UPC / NPC, shaper common), and the number of parameters is reduced by three. .

FIG. 4 shows an example of the required memory amount in the case of the embodiment (2), and shows an example when the number of connections accommodated is 256 connections. According to this embodiment, the memory amount is 1 compared to the conventional case.
2K bits are reduced.

Next, according to the present invention, not only the above-described method for traffic control but also an apparatus for performing traffic control using such a method can be provided.

FIG. 5 shows an embodiment (3) of the present invention and shows an example of the apparatus configuration of the present invention. In FIG. 5, 1 is a storage device for storing cell data for writing input cell data, 2 is an output control unit for reading and outputting the data of the corresponding cell from the storage device 1 for storing cell data at the cell output time, 3 Is a cell detector for reading out control data described in the header of the arrived cell, 4
Is an operation unit that performs a violation determination and calculates the output time of a cell. Reference numeral 5 manages the address of the cell data written in the cell data storage device 1 based on the output time input from the operation unit 4. A memory controller, 6 is a storage device for storing parameters for storing traffic parameters, 7
Is an arithmetic storage device for storing arithmetic parameters,
Reference numeral 8 denotes a memory control storage device for managing the address of cell data.

The parameter storage memory 6 and the arithmetic memory 7 store required parameters for each cell type. When a cell arrives, the cell detection unit 3 reads the control data described in the header of the cell and identifies the cell type. In the calculation unit 4, the parameter storage storage device 6 and the calculation storage device 7 are used as necessary.
While accessing, the violation determination and the output time calculation are performed according to the above algorithm for each cell type.

The memory control unit 5 manages the address of the cell data written in the cell data storage device 1 based on the cell output time input from the arithmetic unit 4. The memory control storage device 8 stores data necessary for managing the cell data address. The output control unit 2 reads out and outputs the data of the corresponding cell from the cell data storage device 1 at the cell output time.

In traffic control, UPC
In consideration of the case where the (NPC) or the shaper is operated alone, in the device of the present invention, the UPC is performed by mode switching by hardware or software control.
It is possible to operate as a single (NPC) or a single shaper.

A parameter storage memory device 6 for storing traffic parameters in the apparatus, an operation memory device 7 for storing operation parameters, a cell data memory device 1 for writing input cell data, Regarding the memory control storage device 8 for storing the data necessary for managing the address of the cell data, there are two types: a case where they are built in the LSI and a case where they are externally attached to the LSI.

When the storage device is built in the LSI, L
SI can be realized with one chip, and UPC (NP
C), the shaper can be realized in the smallest size. Storage device is L
When the external storage device is attached to the SI, compared with the case where the storage device is built in the LSI, a high technology is not required, and the number of accesses to the external storage device is reduced due to the reduction in the required memory amount. UP storage with lower storage available
C (NPC) and shaper can be realized at low cost.

[0065]

As described above, according to the present invention, the minimum cell interval T of the traffic monitoring parameters used in the usage parameter control and the inter-network usage parameter control and the cell output time of the traffic shaper. Since the minimum cell interval T of the parameters used to obtain the parameter is expressed by one common parameter, the memory amount required for the UPC (NPC) and the shaper can be reduced and The amount of software management memory can also be reduced, and the parameter setting time can be shortened. Also, UP
Since a part of the circuit of C (NPC) and the shaper can be shared, the circuit scale can be reduced.

Further, in the above-mentioned apparatus for performing traffic control, when the storage device is built in the traffic control apparatus, the UPC (NPC) and the shaper can be realized by one apparatus, so that the traffic control can be made the smallest. The device can be realized. Further, when the storage device is externally attached to the traffic control device, the number of accesses to the external storage device is reduced by reducing the required memory amount.
It becomes possible to use a low-performance (slow) storage device, and UPC (NPC) and shaper can be realized at low cost.

[Brief description of drawings]

FIG. 1 is a diagram showing an embodiment (1) of the present invention.

FIG. 2 is a diagram showing an example of a required memory amount in the embodiment (1).

FIG. 3 is a diagram showing an embodiment (2) of the present invention.

FIG. 4 is a diagram showing an example of a required memory amount in the embodiment (2).

FIG. 5 is a diagram showing an embodiment (3) of the present invention.

FIG. 6 is a diagram showing deployment positions of UPCs, NPCs, and shapers in an ATM network.

FIG. 7 is a diagram showing an example of a UPC algorithm (virtual scheduling algorithm).

FIG. 8 is a diagram showing an example of a shaping algorithm (virtual scheduling algorithm).

[Explanation of symbols]

T minimum cell spacing τu CDV tolerance τs CDV residual value TAT theoretical cell arrival time Tout cell output time ta cell arrival time X leaky bucket counter X'temporary calculated value of leaky bucket counter Arrival time of cell before LT ta cell arrival time 1 Cell data storage device 2 Output control section 3 cell detector 4 computing section 5 Memory controller 6 Parameter storage device 7 Computing storage device 8 Memory control storage device

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Shinji Ota, 1-1 1-1 Kamiodanaka, Nakahara-ku, Kawasaki-shi, Kanagawa Fujitsu Limited (72) Inventor Toshinori Koyanagi 4-chome, Ueodaanaka, Nakahara-ku, Kawasaki, Kanagawa No. 1 in Fujitsu Limited (72) Inventor Takashi Yamashita 3-19-2 Nishishinjuku, Shinjuku-ku, Tokyo Inside Nippon Telegraph and Telephone Corporation (56) Reference JP-A-6-315034 (JP, A) Kaihei 7-74757 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H04L 12/28

Claims (7)

(57) [Claims] 1. In traffic control performed in an ATM network in which information to be communicated is divided into fixed-length cell units and transferred asynchronously, a violation of a traffic amount with respect to a negotiated parameter is detected and a predetermined action is taken. Among the parameters used for traffic monitoring in UPC or NPC control,
The minimum cell interval calculated from the negotiated cell rate and the minimum cell interval calculated from the negotiated cell rate are common among the parameters used in the shaper control to reduce the cell delay fluctuation and shape the traffic characteristics to the desired shape. By using the above two types of control, the input ATM cell and the previously input A of the same connection can be expressed.
When the distance from the TM cell violates the minimum cell interval obtained from the negotiated traffic volume stored in the storage device and exceeds the threshold stored in the storage device. Traffic control method characterized by not passing through the cell, adjusting the cell output time when it is within the threshold value and outputting at the desired time, and passing through the cell as it is if it does not violate the minimum cell interval . 2. The traffic control method according to claim 1, wherein a mode for performing the UPC or NPC control,
A traffic control method, characterized in that a mode for controlling a shaper is provided, and one of the controls can be selected and performed by mode switching. 3. The traffic control method according to claim 1, wherein the traffic monitoring method in the UPC or NPC control and the output time calculation method in the shaper control are applied when a virtual scheduling algorithm is used. . 4. The leaky bucket algorithm is used as a traffic monitoring method in the UPC or NPC control and an output time calculating method in the shaper control, which is applied.
The traffic control method described in. 5. A cell detection unit that reads out control data described in a header portion of an input cell to detect a cell type, a storage device for storing parameters that stores traffic parameters negotiated for each cell type, Using the stored traffic parameters, a calculation unit that detects a traffic amount violation for an input cell according to a predetermined algorithm for each cell type and calculates the output time of the cell, and a calculation parameter used for the calculation in the calculation unit And a memory control unit for managing the address of the stored cell data based on the cell output time input from the arithmetic unit. A memory for controlling memory for storing data required for address management of the cell data, and the memory The traffic control device according to claim 1, further comprising: an output control unit that outputs the data of the corresponding cell from the storage device for storing cell data according to an output address of the control unit at a required output time. . 6. An LS for accommodating the traffic control device, the parameter storage memory device, arithmetic memory device, cell data storage memory device, and memory control memory device.
The traffic control device according to claim 5, wherein the traffic control device is incorporated in I. 7. The traffic control device according to claim 5, wherein the parameter storage memory device, the arithmetic storage device, the cell data storage memory device, and the memory control memory device are externally attached to the traffic control device. Traffic control device.