JP3157113B2 - Traffic shaper device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a traffic shaper in an asynchronous transfer mode type communication network, and is particularly suitable for a case where cells having different service attributes are mixed.

[0002]

2. Description of the Related Art In recent years, in the field of information communication, with the diversification of communication needs, advancement of information exchange / transmission technology, development of device technology, etc., high-speed exchange and transmission of user information at high speed and wide band are possible. The practical use of a broadband integrated services digital network (hereinafter, B-ISDN) is rapidly progressing.

In the B-ISDN, an asynchronous transfer mode (hereinafter, referred to as ATM) is employed as an information transfer method. In this ATM communication, information is transferred and exchanged in fixed-length packets called cells. in this case,
The cell transfer destination is identified based on destination address information assigned to each cell.

[0004] Therefore, unlike the conventional time-division circuit switching, each terminal can transmit a cell to an arbitrary position of a slot on a vacant time axis, and can transmit a cell to an arbitrary position on a transmission line in a network. Cell multiplexing becomes possible.

[0005] Therefore, in the ATM communication, each terminal declares a cell communication band (for example, a peak cell rate or an average cell rate) to be used before starting communication, and the network side performs band management based on the information. One of the intra-network band management functions is cell output band regulation (hereinafter, shaper). This shaper absorbs cell delay fluctuation (hereinafter, CDV) caused by output queuing when a plurality of cells heading for the same route arrive at the same time during cell multiplexing and switching processing in a network, This is a function for transmitting a cell to an output line according to a user declared value.

Conventionally, several methods have been proposed as shaper methods. One of them is described in the literature (eg, "The Spacing Policer, An Algorithm for Effici
entPeak Bit Rate Control in ATM Networks ", ISS'92, N
o.A5.5, Yokohama, October 1995) is a Spacing Policer. In this method, a scheduled transmission time that satisfies a declared value is calculated for each arriving cell, and cells queued for each calculated scheduled transmission time are sequentially read out and transmitted one by one, thereby generating an intra-network occurrence. The aim is to reduce CVD and achieve cell transmission that satisfies the user declared value.

FIG. 2 is a diagram showing a basic device configuration of the shaper device. As shown, the shaper device 201
Is a cell identification & scheduled transmission time calculation unit 202 for identifying a valid cell for each arrival cell and calculating a scheduled transmission time τ, and a cell scheduler unit 203 for temporarily storing arrival cells and scheduling cell transmission according to the scheduled transmission time τ. And a clock 204 for giving the current time CT to the cell identification & scheduled transmission time calculation unit 202 and the cell scheduler unit 203. Also, the cell identification & scheduled transmission time calculation unit 202
Holds user reported value information and various parameters to be described later for all connections during communication. The clock 204 has a cycle Tmax, and the current time C is incremented by one every one cell time.
Increment T.

In FIG. 2, when a cell 205 arrives,
First, the cell identification & scheduled transmission time calculation unit 202 identifies whether the cell is valid, and notifies the cell scheduler unit 203 of the identification result. Further, if this cell 205 is a valid cell,
From the information of the connection to which the cell 205 belongs, the required delay time is calculated to determine how much the cell 205 is delayed in the cell scheduler unit 203 to satisfy the declared value, and a scheduled transmission time τ is calculated based on the delay time. Provided to the cell scheduler unit 203. Also, the cell scheduler unit 203 places the cell 205 at the end of the cell buffer unit queued for each scheduled transmission time τ based on the received scheduled transmission time τ only when the arriving cell is a valid cell. It is stored and transmitted one cell at a time as the clock 204 elapses.

FIG. 3 is a block diagram showing a conceptual configuration of a conventional cell scheduler unit. As shown in the figure, a cell scheduler unit 301 includes a cell memory (hereinafter, also simply referred to as a CM) 302 for storing an arrival cell and pointer groups 307 to 309 for controlling address information of the cell memory 302.
It consists of. The cell memory 302 includes an element group 306 in units of one cell.

FIG. 4 is an enlarged view of one of the elements constituting the element group 306. A cell storage field (hereinafter, CBF) 4 for storing information for one cell is shown.
02 and an address pointer (hereinafter, APtr) 401 indicating another element. By using the address pointer 401, an element can be linked to another element in a daisy chain.

The cell memory 302 also has a free list for managing unused elements (hereinafter simply referred to as FL).
303, a calendar queue (hereinafter, also simply referred to as CQ) 304 in which cells waiting for connection are stored for each scheduled transmission time, and an output list (hereinafter, OL) for managing cells in an output waiting state. Description) 3
05.

The free list 303 is stored in the cell memory 302.
Are linked, and the addresses of the first element and the last element are assigned to the free list header (hereinafter, F) of the free list pointer 307.
LH) pointer and free list tail (hereinafter, referred to as LH)
FLT) are stored by pointers.

The calendar queue 304 has a clock cycle Tma
Arrived cells are linked and stored for each scheduled transmission time of x minutes, and each linked cell group, like the free list 303, has a calendar queue header (hereinafter, CQH) of a calendar queue pointer group 308, a calendar queue tail. (Hereinafter, CQT) indicates the first element and the last element. If no cell is connected at the scheduled transmission time, the CQH pointer and the CQT pointer indicate invalid information without indicating anything.

In the output list 305, a cell group whose current time CT coincides with the scheduled transmission time has been moved and stored. The output list header (OLH) of the output list pointer 309 and the output The first element and the last element are indicated by a list tail (hereinafter, OLT). The cells stored in the output list 305 are sequentially transmitted from the head cell to the output line 312 one cell at a time, one cell at a time.
Good . The empty element after the cell is delivered is connected to the end of the free list 303 again, Ru is used to store the subsequent arriving cell.

Although the cell memory 302 is logically divided into a free list 303, a calendar queue 304, and an output list 305, it is physically one.
It is realized by one shared memory, free list 3
03 to the calendar queue 304 and further to the output list 305 are all performed by pointer processing, and the cell information itself in each element does not move.

[0016]

As described above, conventionally, a scheduled transmission time that satisfies the user's report value for each arrival cell is calculated based on the previous cell arrival time, and the arrival cell is calculated in units of the scheduled transmission time. Is temporarily stored in the cell scheduler, and when the current time of the clock reaches the scheduled transmission time, the cells stored in the time sequence are moved to the transmission wait queue and sequentially transmitted from the first cell. With that, the shaper function was realized.

However, in such a configuration, the AT
It cannot respond to the best-effort service required in M communication. This best-effort service mainly uses non-immediate data communication over ATM.
This service is provided to improve the use efficiency of the network when it is performed via the network.

In a normal service, as described above, a communication band to be used is declared in advance by a terminal, and a band is limited in a network based on the communication band (hereinafter, a band securing type service). In contrast, best-effort services offer:
Not the communication band to be used but only the required minimum band (hereinafter referred to as ABR service: Avairable Bit R)
ate) or does not declare the bandwidth (hereinafter U
BR service: Unspecified Bit Rate). In the network, cells belonging to this best-effort service are:
Transmission is possible only when there is no cell of the band securing type service to be transmitted, and in the case of ABR service, a minimum band is reserved.

In the conventional shaper device,
When trying to provide these best-effort services in combination with the bandwidth securing services, it is impossible to calculate the scheduled transmission time of the cells of the best-effort services, and since the two are not separated, the calendar queue And there is a problem that the original best-effort service cannot be provided.

The present invention has been made in view of the above problems, and provides a traffic shaper device capable of performing ATM communication without impairing the respective service characteristics even when cells having different service attributes are mixed. With the goal.

[0021]

According to a first aspect of the present invention, there is provided a traffic shaper apparatus for regulating an output band of a cell based on a band regulation request. It is characterized by the following.

[0022] That is, (1) identifying means for identifying service type belongs arriving cell, genus (2) arriving cell
If the service type to be used is the type that secures the output bandwidth
In this case, the scheduled transmission time of the cell is set every time the cell arrives.
Calculating means for calculating based on the output band parameter,
(3) For each scheduled transmission time calculated by this calculation means,
All connections of service types that secure power bandwidth
Queuing means for queuing cell of
The service type to which the arriving cell belongs guarantees the output bandwidth
If the type does not need to be
All service types that do not need to guarantee power bandwidth
Storage method for storing in a common buffer for connections
And (5) when the cell transmission time is updated,
The scheduled cell transmission time or the earlier time
Is queued in the queuing means.
Send the cell when it is
A cell whose scheduled time is a time or a time earlier than the time
Is not queued by the queuing means
Sending the oldest cell stored in said storage means to come
And sending means for performing the operation.

[0023] Also, to solve the above problems, in the second invention, based on the bandwidth regulatory requirements, the traffic shaper device to perform regulation of the output bandwidth of the cell, that comprises the following means Features.

That is, (1) the service to which the arriving cell belongs
Identification means for identifying the service type, and (2)
If the service type to be used is the type that secures the output bandwidth
In this case, the scheduled transmission time of the cell is set every time the cell arrives.
Calculation method for calculating based on the output band parameter
And (3) the scheduled transmission time calculated by the first calculating means
The service type of the type that secures the output bandwidth
Queuing to queue cells for all connections
Means and (4) the service type to which the arriving cell belongs
When the type requires only the output band to be guaranteed
Each time the cell arrives, the maximum wait time of the cell
Second calculation based on cell output band parameter
Means and (5) the maximum wait calculated by the second calculating means.
It is necessary to guarantee only the minimum output bandwidth for each possible time unit
Cells of all connections of a certain type of service type
Second queuing means for queuing; (6) cells
When the transmission time is updated, the updated cell transmission time
Or a time earlier than that as the maximum possible time
The queued cell is queued to the second queuing means.
If so, the cell is sent and the updated cell is sent.
When the maximum time can be reached at or before the departure time
The cut cell is queued to the second queuing means.
Cell has not been updated and the cell transmission time has been updated or
The cell whose scheduled time is earlier than that time is
When queued by one queuing unit
Sends the cell and the updated cell sending time or
A cell with a time earlier than the maximum waiting time is
Queued in the second queuing means
And the updated cell transmission time or earlier
The cell whose time is the scheduled transmission time is the first queue-in cell.
When the queue means is not queued,
Send out the oldest cell stored in the queuing means
And sending means .

[0025]

DESCRIPTION OF THE PREFERRED EMBODIMENTS (A) First Embodiment Hereinafter, a first embodiment of a traffic shaper device according to the present invention will be described in detail with reference to the drawings.

(A-1) Configuration of the First Embodiment The shaper device of the present invention also basically has the configuration shown in FIG. 2 described above . a cell identification & scheduled output time calculation unit 202 that calculates the identified sending predetermined time tau and the cell scheduler 203 performs scheduling of cell transmission according to the scheduled output time stores arriving cells once tau, cell identification and sending predetermined time to calculator 202 and the cell scheduler unit 203 gives the current time CT composed from the clock 204..

In FIG. 2, when the cell 205 arrives,
The cell identification & scheduled transmission time calculation unit 202 first identifies whether the cell belongs to the band securing type service or the best effort type service from the information of the connection to which the cell belongs, and notifies the scheduler unit.
At this time, if the cell 205 is a cell of the band securing type service, a required delay time is calculated to determine how long the cell is delayed in the cell scheduler unit 203 to satisfy the declared value, and based on the calculated delay time τ Is calculated and provided to the cell scheduler 203. As described above, in the present embodiment, the cell identification & scheduled transmission time calculation unit 202 has a function of performing even the identification of a service type as to whether the arriving cell is of the band securing type or the best effort type.

FIG. 1 is a block diagram showing a conceptual configuration of a first embodiment of a scheduler unit in a shaper device according to the present invention. In the present embodiment, a case will be described in which the UBR service among the best effort services is mixed with the band securing type service.

[0029] The cell scheduler 101, cell identification and the cell identification information input from the scheduled output time calculation unit via the signal line 116, also input via a signal line 115 from the cell identification & scheduled output time calculating unit and cell sending scheduled time τ that is, enter respectively the current time CT which is inputted via the signal line 117 from the clock, based on these, the arriving cell input via the signal line 113, secured bandwidth The transmission is performed to the output line 114 while scheduling according to each of the service and the UBR service.

The cell scheduler 101 includes a cell memory 102 for storing an arrival cell, pointer groups 108 to 111 for controlling the address information of the cell memory 102, and a selector 112 for selectively outputting a cell for the band securing type service and a cell for the UBR service. Consists of

The cell memory 102 is composed of an element group 107 for each cell. FIG. 4 described above shows this
Also be one obtained by enlarging the one of the elements in the first embodiment, an address pointer 401 which points to the cell storage field 402 and other elements for storing information of one cell. By using this address pointer, the elements are linked in a daisy chain with other elements.

The cell memory 102 may also free list for managing unused element (hereinafter, FL) 10 3, calendar queue (hereinafter, CQ) the cells in waiting is stored are connected to each sending predetermined time 104 , An output list (hereinafter, OL) 105 for managing cells in an output waiting state, and a UBR queue (hereinafter, UBRQ) 106 for storing cells belonging to the UBR service. Here, the free list 103 is
The calendar queue 104 and the output list 105 are used only for cells of the band securing type service, and the UBR queue 106 is used only for cells of the UBR service.

The free list 103 is stored in the cell memory 102
Are linked, and the addresses of the first element and the last element are linked to the free list header (hereinafter, F
LH) Pointer and free list tail (FLT)
Each is stored by a pointer.

The calendar queue 104 has a clock cycle Tma
Arrival cells belonging to the band securing type service are linked and stored at every scheduled transmission time of x minutes, and each linked cell group is stored in the calendar queue header (hereinafter referred to as a calendar queue pointer group 109) similarly to the free list 103. , C
QH) and a calendar queue tail (hereinafter, CQT) indicate the first element and the last element.
If no cell is connected at the scheduled transmission time, the pointers CQH and CQT indicate nothing and indicate invalid information.

A cell group whose current time CT coincides with the scheduled transmission time is moved and stored in the output list 105. The output list header (hereinafter, OLH) of the output list pointer 110 and the output The first element and the last element are indicated by a list tail (hereinafter, OLT). Cells stored in the output list 105 is output to sequentially output line 119 One not a 1 cell 1 cell time (finally from the first cell
To the power line 114) . The free element after the cell has been transmitted is connected to the tail end of the free list 103 again, Ru is used to store the subsequent arrival cell.

The UBR queue 106 stores cells belonging to the UBR service linked in the order of arrival.
The UBR header of the UBRQ pointer 111 (hereinafter referred to as UB
RH) and UBR tail (hereinafter, UBRT) indicate the first element and the last element. Of course, if no cell is connected, the pointer UB
RH and UBRT do not indicate anything and are invalid information. The UBR service cell stored in the UBR queue 106 is output to the output line 120 only when there is no band securing type cell waiting to be transmitted, that is, when no cell is stored in the output list 105. At this time, selector
The rectifier 112 performs a process of outputting the cell from the UBR queue 106 to the output line 114.

(A-2) Operation of First Embodiment Hereinafter, the operation of the shaper device of the first embodiment will be described in detail.

Here, the clock of the shaper device, as shown in FIG.
It is assumed that the current time CT is always incremented by one for each cell time, and the current time CT is supplied to the cell identification & scheduled transmission time calculation unit 202 and the cell scheduler unit 203.

First, the operation of the cell scheduler will be described. FIG. 5 is a block diagram showing a basic device configuration of the cell scheduler unit 501, and includes a cell memory (CM) 502,
It comprises a memory (MEM) 503, register groups 504, 505 and 506, selection circuits (SEL) 507 and 508, and a control circuit 509.

The cell scheduler section 501 includes, as external interfaces, a cell input (signal line 510), a cell output (signal line 511), and a scheduled transmission time τ (signal line 512) from a cell identification & scheduled transmission time calculation section. Cell identification information (signal line 514) and current time CT (signal line 513) from a clock are input via respective signal lines.

As shown in FIG. 4, the cell memory 502 stores an address pointer (APt) indicating a connection destination address.
r) and a cell storage field (CB) for storing the arrival cell.
F) is a memory having one element, and realizes the free list 103, the calendar queue 104, the output list 105, and the UBR queue 106 in FIG. The reading and writing operations of the cell memory 502 are controlled by the control circuit 509 via the control line 533.

The memory 503 stores a pointer C indicating the head element address of a cell element linked and stored in the calendar queue in units of scheduled transmission time.
QH and a pointer CQT indicating the last element are stored for a clock cycle (0 to Tmax). The reading and writing operations of the memory 503 are controlled by the control circuit 509 via the control line 535.

The register 504 stores the unused elements in the cell memory 502 linked in the free list.
It holds a pointer FLH indicating the head element address and a pointer FLT indicating the end element address. Similarly, the register 505 includes a pointer O indicating the head element address of a cell element to be output in the cell memory 502 connected to the output list.
LH and a pointer OLT indicating the last element address
And holding. Further, the register 506 stores the UBRQ
Holds a pointer UBRH indicating a head element address and a pointer UBRT indicating a last element address of the UBR service cell element in the cell memory 502 connected thereto. Registers 504, 505
And 506 are controlled by control circuit 509 via control line 534.

The selection circuits 507 and 508 select the address information 519 and 521 when reading and writing the cell memory 502 and the memory 503, respectively, and the selection operation of both of them is performed via control lines 520 and 536. 5
09. The address information to the cell memory 502 includes FLH input through a signal line 515.
Alternatively, FLT, CQ input via the signal line 516
H or CQT, O input through the signal line 517
Either LH or OLT, or UBRH or UBRT input via the signal line 518 is selected. Address information to the memory 503 is stored in a signal line 512.
Is selected from the cell identification & scheduled transmission time τ input from the scheduled transmission time calculation unit or the current time CT input from the clock input via the signal line 513.

The control circuit 509 includes the cell scheduler 5
01, which controls writing and reading operations of the cell memory 502 and the memory 503, and registers 504 to
The latch timing (write timing) of 506 and the selection processing operation of the selection circuits 507 and 508 are controlled.

Next, the operation of the cell scheduler 101 of the first embodiment will be described in the order of arrival cell processing and cell transmission processing with reference to the block diagram of FIG.

[Arrival Cell Processing of Cell Scheduler Unit 101] When a cell to be subjected to band regulation of either the band securing type service or the UBR service arrives, the arriving cell is first unused in the cell memory 502 indicated by the FLH pointer 504. It is temporarily stored in the cell storage field CBF of the element.
At this time, the selection circuit 507 selects and outputs the FLH input via the signal line 515, and uses it as an address input of the cell memory 502. Here, if there is no unused element in the free list, the arriving cell is discarded, and the subsequent processing is not performed.

When the arrival cell is stored, the FL
Since the unused element indicated by H504 is to be allocated to the arrival cell, the FLH pointer needs to be updated. That is, the APtr of the element storing the arrival cell indicated by the FLH pointer so far.
Since the unused element indicated by the pointer is the next unused element at the head, the APtr pointer value may be used as it is via the signal line 523 as the new FLH pointer.

At this time, if the number of remaining unused elements becomes one, the FLT pointer also points to the same unused element as the FLH pointer, so that the signal line 523 is also connected to the FLT pointer 504. I have. Further, when the arriving cell is stored in the last unused element, the remaining unused elements are lost, and the FLH and FLT pointers become invalid.

Next, the element storing the arrival cell undergoes different processing depending on the service to which the cell belongs. The attribute of the service is determined based on the cell identification information 514.

In the case of the band securing type service, the element storing the arriving cell corresponds to the scheduled transmission time τ in the calendar queue from the free list by pointer processing according to the scheduled transmission time τ from the cell identification & scheduled transmission time calculation unit. To the waiting cell row. This processing is performed by using the memory 503 read out using the scheduled transmission time τ as an address.
The old FLH pointer value is written to the APtr pointer in the last element of the element column in the calendar queue indicated by the CQT pointer in
The QT pointer is also realized by setting the old FLH pointer value via the signal line 532. If no cell exists in the connected element column corresponding to the scheduled transmission time τ, the old FLH pointer value becomes the CQH and CQT pointers as they are via the signal line 532.

In the case of the UBR service, the element storing the arrival cell is moved to the end of the UBRQ element sequence. This processing can be realized by writing the old FLH pointer value via the signal line 524 to the APtr pointer in the last element indicated by the UBRT pointer 506, and making the UBRT pointer also the old FLH pointer value via the signal line 531. . If there are no cells connected in the UBRQ, the old FLH pointer value becomes the UBRH and UBRT pointers via the signal line 531 as they are.

[Cell transmission process of cell scheduler section 101] Upon receiving the current time CT from the clock via the signal line 513, the cell scheduler section 501 outputs a linked cell group in the calendar queue corresponding to the current time CT to the output list. Is performed.

First, the selection output 521 of the selection circuit 508
Is set to the current time CT. Using the current time CT as an address, a cell group in the cell memory 502 indicated by the CQH and CQT pointers read from the memory 503 is moved to the output list.

If there are no remaining cells in the output list, the CQH and CQT pointers are
The OLH and the OLT pointer 505 are input as they are through the lines 29 and 530. If only one cell moves, the CQH pointer value is the OLH and OL
It becomes a T pointer.

If there is already a cell in the output list, the cell group indicated by the CQH and CQT pointers is connected to the end of the cell group.
The CQT pointer value is set in the LT pointer, and the old OL
The APtr pointer value of the element in the cell memory 502 indicated by the T pointer newly becomes the CQH pointer (signal line 522). Here, when only one cell moves, both the APtr pointer and the OLT pointer are set to the CQH pointer value (signal lines 522, 5
29).

The cell group moved to the output list is sequentially transmitted from the output line 511 one cell at a time, one cell at a time. Cell storage field CBF of the first element in the output list indicated by the OLH pointer
Is transmitted from the output line 511, the next element in the output list indicated by the APtr pointer of the element becomes the head.
The pointer value is input to the OLH register via the signal line 527 and becomes a new OLH pointer of OLH.

When the number of remaining cells in the output list becomes one due to cell transmission, the OLT and the OLT are used together.
A pointer is also set to the APtr pointer value. If there are no remaining cells in the output list due to cell transmission, both the OLH and OLT pointers become invalid.

The old head element in the output list from which the cell has been sent becomes an unused state and is moved to the free list again. This is because the old OLH pointer value is FL
The APtr pointer (signal line 526) of the last element in the free list indicated by the T pointer 504;
This is realized by writing to the T pointer (signal line 525). If there is no unused element in the free list, the FLH pointer 504 is also set to the old OLH pointer value via the signal line 525.

If there is no cell waiting for transmission in the output list at the time of cell transmission, a cell of the UBR service is transmitted. That is, the cell of the first element among the elements connected in the UBRQ is transmitted to the output line 511. When a cell in the cell storage field CBF of the head element in the UBRQ indicated by the UBRH pointer 506 is output, the next element in the UBRQ indicated by the APtr pointer of the element becomes the head, so that the APtr pointer value becomes the new UBRH pointer. (Signal line 538).

As a result of cell transmission, the number of remaining cells in the UBRQ becomes 1
If it becomes a cell, the UBRT pointer is also set to the all APtr pointers along with the UBRH. When there are no more cells in the UBRQ due to cell transmission,
The BRH and UBRT pointers are both invalid.

The old head element in the UBRQ to which the cell has been sent becomes an unused state and is moved to the FL again. This is because the old UBRH pointer value is the FLT pointer 504
APt of the last element in the free list pointed to by
This is realized by writing to the r pointer (signal line 528) and the FLT pointer (signal line 537). If there are no unused elements in the free list,
The FLH pointer 504 is also set to the old OLH pointer value (signal line 537).

(A-3) Effects of the First Embodiment According to the traffic shaper device of the first embodiment described above, the following effects can be obtained.

(1) In a shaper device for regulating the output band of ATM cells, even in an ATM line where cells belonging to a band securing type service and cells belonging to a UBR type best effort service are mixed, the band management of both services is performed. Can be realized by the same hardware.

(2) In the shaper device, the cell for the band securing type service and the cell for the UBR service are logically separated and stored, so that they do not interfere with each other, and It is possible to always transmit data with priority, and when there is no cell of the band securing type service, the cell of the UBR service can be transmitted immediately, so that the use efficiency of the network can be improved.

(3) The amount of hardware in the present embodiment is increased by only two UBR service queue pointers as compared with the conventional configuration. Therefore, it is possible to easily mix the UBR service with the band securing type service only by adding a pointer register with almost no increase in hardware.

(4) As described above, the cell for the band securing type service and the cell for the UBR service are logically separated and stored, but the storage memory is physically shared and used. It is expected that the use efficiency of the memory will be improved and the required memory capacity will be reduced.

(5) The biggest feature of the shaper device used in the present embodiment is that a huge number of connections can be bandwidth-controlled at the same time, but various processes are executed only when cells arrive and when cells are transmitted. Therefore, the features of the present embodiment are not impaired at all, and the number of connections is not limited.

(B) Second Embodiment Next, a second embodiment of the traffic shaper according to the present invention will be described in detail with reference to the drawings.

(B-1) Configuration of Second Embodiment Like the first embodiment, the shaper device of this embodiment also has a basic configuration as shown in FIG. a cell identification & scheduled output time calculation unit 202 that calculates the identified sending predetermined time tau and the cell scheduler 203 performs scheduling of cell transmission according to the scheduled output time stores arriving cells once tau, cell identification and sending predetermined time Calculation unit 202 and cell scheduler unit 20
3 to consists of 204 Metropolitan clock that gives the current time CT.

In FIG. 2, when the cell 205 arrives, the cell identification & scheduled transmission time calculating unit 202 determines whether the cell belongs to the band securing type service or the best effort type service based on the information of the connection to which the cell belongs. Is first identified and notified to the scheduler unit. Further, if the cell is a band securing type service cell, a required delay time is determined as to how long the cell is delayed in the cell scheduler unit 203 to satisfy the declared value, and a scheduled transmission time τ is calculated based on the delay time. Provided to the cell scheduler unit 203.
Best-effort service (ABR service)
In the case of, the longest possible waiting time of the cell is calculated, and the latest cell transmission possible time is calculated based on the longest possible waiting time, and is provided to the cell scheduler unit 203 as the scheduled transmission time τ. That is, the cell scheduler unit 203
However, if the cell is transmitted within the scheduled transmission time τ,
It is possible to guarantee the minimum bandwidth for the connection to which the cell belongs.

FIG. 6 is a block diagram showing a conceptual configuration of the second embodiment of the cell scheduler 601 in the shaper device according to the present invention. In the present embodiment, a case will be described in which the ABR service among the best effort services is mixed with the band securing type service.

[0073] The cell scheduler 601, cell identification information input via the signal line 618 from the cell identification & scheduled output time calculating unit is input via the signal line 617 from the cell Le identification & scheduled output time calculating unit that cell sending scheduled time tau, based on the current time CT which is inputted via the signal line 619 from the clock, the arriving cell input via the signal line 615, the band-guaranteed service, each its ABR service <br According to this, the output line 616 is performed while scheduling.
To send to.

The cell scheduler unit 601 includes a cell memory 602 for storing an arrival cell, a group of pointers 609 to 613 for controlling the address information of the cell memory 602, a selector 614 for selectively outputting a cell for the band securing type service and a cell for the ABR service. And a register (REG) 624 holding the number of cells stored in the ABR service.

The cell memory 602 is composed of an element group 608 in units of one cell. In this second embodiment
Each element, as shown in FIG. 4, comprises a cell storage field 402 for storing information for one cell and an address pointer 401 for pointing to another element. By using this address pointer, the elements are linked in a daisy chain with other elements.

The cell memory 602 also includes a free list (FL) 603 for managing unused elements, and a calendar queue (CQ) in which cells waiting for a band securing type service are linked and stored at each scheduled transmission time. 60
4. An output list (OL) 505 for managing cells in an output waiting state, an ABR queue (ABRQ) 606 in which waiting cells belonging to the ABR service are linked and stored at each scheduled transmission time, and an output. ABR output list (A
(BROL) 607. Here, the free list 603 is used commonly for both the band securing type service and the ABR service.
4 and the output list 605 are used only for cells of the bandwidth reservation type service, and the ABR queue 606 and the ABR output list 607 are used only for cells of the ABR service.

The free list 603 is stored in the cell memory 602
All the unused elements are connected, and the addresses of the first element and the last element are stored by a free list header (FLH) pointer and a free list tail (FLT) pointer of the FL pointer 609, respectively.

The calendar queue 604 has a clock cycle Tma
Arrival cells belonging to the band securing type service are linked and stored at every scheduled transmission time of x times, and each linked cell group is stored in the calendar queue header (CQ) of the calendar queue pointer group 610 similarly to the free list 603.
H), the first element and the last element are indicated by a calendar queue tail (CQT). If no cell is connected at the scheduled transmission time, the pointers CQH and CQT indicate nothing and indicate invalid information.

In the output list 605, a cell group whose current time CT matches the scheduled transmission time has been moved and stored. The output list header (OLH) of the output list pointer 611 and the output list tail are stored. (OLT) indicates the first element and the last element.

The ABR queue 606 also has a clock cycle Tma
Arrival cells belonging to the ABR service are linked and stored for each of the maximum waiting times for x, and each linked cell group is, like the free list 603, an ABR queue header (ABRQ) of the ABR queue pointer group 612.
H) and the ABR queue tail (ABRQT) indicate the first element and the last element. If no cell is connected at the scheduled transmission time, the pointers ABRQH and ABRQT do not indicate anything and are invalid information.

The REG 624 holds the number of cells stored in the ABR queue 606 for each maximum wait time. That is, each time a cell is stored in the ABR queue 606, the register at the corresponding time position is incremented by one. Conversely, AB from the ABR queue 606
If a cell has moved to the R output list 607, the number of moved cells is subtracted from the register at the corresponding time position, and if the cell has been output directly from the ABR queue 606, 1 is subtracted. You. AB based on this register information
The cell storage position in the R queue 606 can be known, and cells can be directly output from the ABR queue 606 described later.

In the ABR output list 607, a cell group whose current time CT coincides with the maximum wait time is moved and stored, and the output list header (ABROLH) of the ABR pointer 613 and the output list tail are stored. (ABROLT) indicates the first element and the last element.

The output list 605, the ABR output list 607, and the cells stored in the elements in the ABR queue 606 are transmitted according to the following priorities.

(1) If there is a cell waiting to be transmitted in the ABR output list 607, the cell is transmitted with the highest priority.

(2) If there are no cells waiting to be transmitted in the ABR output list 607 and there are cells waiting to be transmitted in the output list 605, the cells in the output list 605 are transmitted.

(3) If neither the ABR output list 607 nor the output list 605 has a cell to be sent, the cell is stored in the time series closest to the current time CT among the cells connected in the ABR queue. Are transmitted sequentially from the current cell. The cell to be output is searched based on the information of REG624.

By performing the priority control as described above, the ABR which needs to guarantee the minimum bandwidth for the bandwidth securing service
Services can be mixed and shaped. (B-2) Operation of Second Embodiment Hereinafter, the operation of the cell scheduler unit in the shaper device of the second embodiment will be described in detail.

Here, the clock of the shaper device, as shown in FIG.
It is assumed that the current time CT is always incremented by one for each cell time, and the current time CT is supplied to the cell identification & scheduled transmission time calculation unit 202 and the cell scheduler unit 203.

First, the operation of the cell scheduler will be described with reference to FIG. FIG. 7 is a block diagram showing the basic configuration of the cell scheduler unit 701.
2. Memory (MEM) 703, register group 704 to 70
6 and 740, selection circuits (SEL) 707 and 708,
And a control circuit 709.

The cell scheduler unit 701 also includes a cell input (signal line 710) as an external interface,
Cell output (signal line 711), scheduled transmission time τ (signal line 712) from cell identification & scheduled transmission time calculation unit , cell identification information (signal line 714), and current time CT from the clock
(Signal line 713).

As shown in FIG. 4, the cell memory 702 stores an address pointer (APt) indicating a connection destination address.
r) and a cell storage field (CB) for storing the arrival cell.
F) is a memory having one element, and realizes the free list 603, calendar queue 604, output list 605, ABR queue 606, and ABR output list 607 in FIG. The read and write operations of the cell memory 702 are controlled by a control circuit 709 via a control line 733.

The memory 703 stores a pointer C indicating a head element address of a cell element connected and stored in the calendar queue in units of scheduled transmission time.
QH and a pointer CQT indicating the last element, and further, for a cell element linked and accumulated in the ABR queue in units of the maximum queuable time, a pointer ABROQ indicating a head element address and a pointer ABRQT indicating a last element, respectively. For the clock cycle (0 to Tmax). Memory 703
The read and write operations of are controlled by the control circuit 709 via the control line 735.

The register 704 stores the unused elements in the cell memory 702 linked in the free list.
It holds a pointer FLH indicating the head element address and a pointer FLT indicating the end element address. Similarly, the register 705 includes a pointer OL indicating a head element address of a cell element to be output in the cell memory 702 connected to the output list.
H and a pointer OLT indicating the last element address. Further, the register 706 holds a pointer ABROLH indicating a head element address and a pointer ABROLT indicating a last element address of an output waiting element of the ABR service in the cell memory 702 connected to the ABROL. Register 70
4 , 705 and 706 are controlled by the control line 734.
Is controlled by the control circuit 709 via the.

The register group 740 (REG0, REG1,.
.., REGTmax) indicates the number of elements connected and stored in the ABR queue to the maximum wait time 0
ＴTmax are counted and held. That is, ABR
Each time a cell belonging to the ABR service is stored in the queue, the register 740 at the corresponding time position is incremented by one. Conversely, if a cell has moved from the ABR queue to ABROL, the number of moved cells is subtracted from the register 740 at the corresponding time position, and if the cell has been output directly from the ABR queue, 1 is subtracted. The control circuit 709 can know the cell storage position in the ABR queue based on the register information, and outputs the read address 736 of the memory 703 when the cell is directly output from the ABR queue to the selection circuit 708.

The selection circuits 707 and 708 select the address information 719 and 721 when performing the read and write operations of the cell memories 702 and 703, respectively.
The selection operation of both is controlled by the control circuit 709 via control lines 720 and 736.

The address information to the cell memory 702 includes
FLH or FL input via signal line 715
T, CQH or C input via signal line 716
Either QT, OLH or OLT input via a signal line 717, ABRQH or ABRQT input via a signal line 718, or ABROLH or ABROLT input via a signal line 742 is selected.

The address information to the memory 703 includes a transmission scheduled time τ from the cell identification & transmission scheduled time calculation unit input via the signal line 712, and a current time CT from the clock input via the signal line 713. Or the control circuit 709
Of the direct output address 743 from is selected. This direct output address 743 is used for ABR when there is no output waiting cell in both the ABROL and the output list.
The address of the memory 703 to be set in order to delivery the cells directly ABR services than BR queue, control from Tei Ru information held in the register group 740 circuit 709
Is determined and generated.

The control circuit 709 includes the cell scheduler 7
01, which controls writing and reading operations of the cell memory 702 and the memory 703, and a register group 704.
706 and 740 latch timing, selection circuit 70
7 and 708, and a cell storage address search operation in direct cell transmission processing from ABRQ.

Next, the operation of the cell scheduler unit 701 according to the second embodiment will be described in the order of arrival cell processing and cell transmission processing with reference to the block diagram of FIG.

[Arrival Cell Processing of Cell Scheduler 701] When a cell subject to band regulation of either the band securing type service or the ABR service arrives, first, the arriving cell is located at the top of the cell memory 702 indicated by the FLH pointer 704. It is temporarily stored in the cell storage field CBF of the used element. At this time, the selection circuit 707 selects and outputs the FLH 715 as an address input to the cell memory 702. Here, if there is no unused element in the free list, the arriving cell is discarded and the subsequent processing is not performed.

When the arrival cell is stored, the FL
Since the unused element indicated by H704 will be assigned to the arrival cell, the FLH pointer needs to be updated. That is, the APtr of the element storing the arrival cell indicated by the FLH pointer so far.
Since the unused element indicated by the pointer becomes the next unused element at the head, the APtr pointer value may be directly used as the new FLH pointer via the signal line 723. At this time, if the number of remaining unused elements becomes one, the FLT pointer also points to the same unused element as the FLH pointer, so the signal line 723 is also connected to the FLT pointer 704.
Further, when the arrival cell is stored in the last unused element, the remaining unused elements are lost,
The FLH and FLT pointers become invalid.

Next, the element storing the arriving cell undergoes different processing depending on the service to which the cell belongs. The service attribute is determined based on the cell identification information 714.

In the case of the band securing type service, the element storing the arrival cell corresponds to the scheduled transmission time τ in the calendar queue from the FL by pointer processing according to the scheduled transmission time τ from the cell identification & scheduled transmission time calculation unit. It is moved to the waiting cell row. This processing is performed at the scheduled transmission time τ
CQT in the memory 703 read by using
The old FLH pointer value is written via the signal line 724 to the APtr pointer in the last element of the element column in the calendar queue indicated by the pointer, and the CQT pointer is also realized by using the old FLH pointer value via the signal line 732. Is done. If no cell exists in the connected element sequence corresponding to the scheduled transmission time τ,
The old FLH pointer value remains unchanged via signal line 732
These are the QH and CQT pointers.

In the case of the ABR service, the element storing the arriving cell is stored in the F by pointer processing according to the maximum wait time τ from the cell identification & scheduled transmission time calculation unit.
L is moved to the waiting cell row corresponding to τ in the ABR queue.

In this process, the ABRO in the memory 703 read using the maximum wait time τ as an address
This is realized by writing the old FLH pointer value to the APtr pointer in the last element of the element sequence in the ABR queue indicated by the Q pointer (signal line 724), and also setting the ABRQT pointer to the old FLH pointer value (signal line 732). . If no cell exists in the connected element column corresponding to the maximum possible waiting time τ, the old FLH pointer value is used as it is for ABRQH and AB
It becomes an RQT pointer (signal line 732). Finally, the value of the register 740 at the corresponding time is incremented by one.

[Cell transmission processing of cell scheduler section 701] Upon receiving the current time CT from the clock via the signal line 713, the cell scheduler section 701 outputs the connected cell group in the calendar queue corresponding to this current time CT to the output list. Then, a process of moving the connected cell group in the ABR queue to ABROL is performed.

For the band securing type service, first, the selection output 721 of the selection circuit 708 is set to the current time CT. Using this current time CT as an address, the memory 70
The cell group in the cell memory 702 pointed to by the CQH and CQT pointers read from No. 3 is moved to the output list. If there are no remaining cells in the output list, the CQH and CQT pointers become the OLH and OLT pointers 705, respectively (signal line 72).
9 and 730). When only one cell moves, the CQH pointer value becomes the OLH and OLT pointers. If there is already a cell in the output list, C
The cell group indicated by the QH and the CQT pointers is connected to the end thereof, and the OLT pointer is connected to the signal line 730.
, The CQT pointer value is set, and the APt of the element in the cell memory 702 indicated by the old OLT pointer is set.
The r pointer value newly becomes the CQH pointer (signal line 722). Here, when only one cell moves, both the APtr pointer and the OLT pointer are set to the CQH pointer value (signal lines 722 and 72).
9).

The same applies to the ABR service. First, the selection output 721 of the selection circuit 708 outputs the current time C
Set to T. Using the current time CT as an address,
ABR queues H and AB read from memory 703
The RQT pointer becomes the ABROLT and ABROLT pointer 706 as they are (signal line 738 and signal line 739). If there is only one cell to move, the ABRQH pointer value will be equal to the ABROLH and ABR
This is the OLT pointer. If there is already a cell in the ABROL, the cell group indicated by the ABRQH and the ABRQT pointer is connected to the end thereof, and the ABROLT
The ABRQT pointer value is set in the pointer (signal line 739), and the CM 70 indicated by the old ABROLT pointer is set.
The APtr pointer value of the element in 2 newly becomes the ABRQH pointer. Here, when only one cell moves, both the APtr pointer and the ABROLT pointer are set to the ABRQH pointer value.
At this time, the number of cells moved from the ABR queue to ABROL is subtracted from the register 740 at the time (that is, cleared to 0).

As described above, the cells stored in the output list, the ABROL, and the elements in the ABR queue are output to the output line 711 according to the following priorities.
It is sent to.

(1) If there is a transmission waiting cell in ABROL,
Sent with the highest priority.

(2) If there are no cells waiting to be transmitted in ABROL and there are cells waiting to be transmitted in the output list, the cells in the output list are transmitted.

(3) If there is no cell waiting to be transmitted in the output list in the ABROL, the cells are sequentially transmitted from the cells connected in the ABR queue which are stored in the time series closest to the current time CT.

[0113] The cell transmission procedure will be described below according to the above-mentioned priorities.

First, there is a case where a cell waiting to be transmitted exists in ABROL. In this case, the cell group moved to ABROL is sequentially output cell 711 one cell at a time per cell.
Is sent out. Cell storage field CB of the first element in ABROL indicated by ABROH pointer
F is output from the output line 711, the next ABRO indicated by the APtr pointer of the element
Since the element in L is at the head, the APtr pointer value becomes a new ABROLL pointer via the signal line 731. When the remaining cells in the ABRO become one by the cell transmission, the ABROLT pointer is set to the APtr pointer value together with the ABROLH. When the remaining cells in the ABROLL are exhausted due to the cell transmission, both the ABROLH and the ABROLT pointer become invalid.

The old head element in the ABROL from which the cell has been transmitted becomes an unused state and is moved to the FL again.
This is realized by writing the old ABROLL pointer value to the APtr pointer (signal line 728) and the FLT pointer (signal line 737) of the last element in the free list indicated by the FLT pointer 704. If there is no unused element in the free list, the FLH pointer 704 is also set to the old ABRORH pointer value via the signal line 737 together with the FLH pointer 704.

Next, there is no cell waiting to be transmitted in ABROL.
The case where there is a cell waiting to be transmitted only in the output list will be described . In this case, group cells connected to the output list, sequentially output lines One not a 1 cell 1 cell time 7
It is sent from 11. When the cell in the cell storage field CBF of the head element in the output list indicated by the OLH pointer is transmitted from the output line 711, the element in the next output list indicated by the APtr pointer of the element becomes the head. So
The APtr pointer value is output to the new OL via the signal line 727.
H pointer. When the number of remaining cells in the output list becomes one due to cell transmission, the OLT pointer is set to all APtr pointers together with OLH. When no cell is present in the output list due to cell transmission, both the OLH and OLT pointers become invalid.

The old head element in the output list from which the cell has been sent becomes unused and is moved to the FL again. This is realized by writing the old OLH pointer value to the APtr pointer (signal line 726) and the FLT pointer (signal line 725) of the last element in the free list indicated by the FLT pointer 704.
If there is no unused element in the free list, the FLH pointer 704 is also added to the signal line 725.
To the old OLH pointer value.

Lastly, a case will be described in which neither the ABROL nor the output list has cells to be sent. In this case, the cells stored in the time series closest to the current time CT among the cells connected in the ABR queue are sequentially transmitted to the output line 711. First, the selection output of the selection circuit 708, that is, the read address of the memory 703 is set in the address information 743 from the control circuit 709. And the ABR of the corresponding maximum wait time
The cell in the cell storage field CBF of the head element in the ABR queue indicated by the QH pointer is output line 7
11, the next element in the ABR queue pointed to by the APtr pointer of the element becomes the head at the time, so that the AP is transmitted via the signal line 744.
The tr pointer value becomes the new ABRQH pointer. If the number of remaining cells in the ABR queue at that time becomes one by the cell transmission, the ABRQT pointer is also set to the APtr pointer value together with the ABRQH. If the remaining cells in the ABR queue for the time lost by the cell delivery is, ABRQH and ABRQT pointers are both invalid.

ABR at the time when the cell was transmitted
The old head element in the queue becomes unused and is moved to the FL again. This is because the old ABRQH pointer value is the APtr pointer of the last element in the free list pointed to by the FLT pointer 704 (signal line 722).
Is written to the FLT pointer (signal line 745). If there is no unused element in the free list, FLH is sent via signal line 745.
The pointer 704 is also set to the old ABRQH pointer value.

When a cell is sent directly from the ABR queue, the value of the register 740 at that time is decremented by "1" and held again.

(B-3) Effects of the Second Embodiment According to the traffic shaper device of the second embodiment described above, the following effects can be obtained.

(1) In a shaper device which regulates the output band of ATM cells, even in an ATM line where cells belonging to a band securing type service and cells belonging to an ABR type best effort service are mixed, the band management of both services is performed. Can be realized by the same hardware.

(2) In the shaper device, the cells of the band securing type service and the cells of the ABR service are logically separated and stored, so that they do not interfere with each other, and the cells of the band securing type service are stored. Since it is possible to always transmit data preferentially, at the same time, when there is no cell of the band securing type service, the cell of the ABR service can be transmitted immediately, and the minimum band required for the ABR service is guaranteed. Thus, it is possible to improve the use efficiency of the network.

(3) The increase in the amount of hardware in the present embodiment is caused by two ABR service queue pointers and the word length (ABRQH) of the memory (MEM) as compared with the conventional configuration.
And ABRQT) only. Therefore, it is possible to easily mix the ABR service with the bandwidth reservation type service without a dramatic increase in hardware.

(4) As described above, the cells of the band securing type service and the cells of the ABR service are logically separated and stored, but the storage memory is physically shared and used. It is expected that the use efficiency of the memory will be improved and the required memory capacity will be reduced.

(5) The biggest feature of the shaper device used in this embodiment is that a huge number of connections can be bandwidth-controlled at the same time, but various processes are executed only when cells arrive and when cells are transmitted. Therefore, the characteristics of the present embodiment are not impaired at all, and the number of connections allowed by the apparatus is not limited.

(C) Other Embodiments Although the present invention has been described in detail with reference to the two embodiments, the present invention is not limited to the above-described embodiments. The present invention can be applied to the traffic shaper device of the present invention.

(1) The cell memory for storing the arriving cell need not be physically one memory, but may be realized by separate memories such as a free list, a calendar queue, and an output list.

(2) In the second embodiment, means for counting the number of cells stored at each maximum wait time is used for searching the storage position of a read cell when cells are transmitted directly from the ABR queue. However, another method may be used as a means for searching for a cell storage position.
A method of increasing the address of M) one by one from the current time CT and searching for a cell to be read may be used.

(3) In the second embodiment, when cells are directly transmitted from the ABR queue, as cells for selecting cells to be read, cells are sequentially transmitted from the cell stored in the time series closest to the current time CT. However, it is also possible to adopt a method of transmitting data in the order of cell arrival without being caught by this.

(4) In the first embodiment, the configuration has been described in which the UBR service among the best effort services and the ABR service in the second embodiment are mixed together with the band securing type service, and the shaping is performed. It is also possible to support all of the band securing type service, the ABR service, and the UBR service together. This case can be realized by combining the first embodiment and the second embodiment and setting the transmission priority of cells belonging to the UBR service to the lowest.

(5) In the second embodiment, an example has been described in which the cell transmission priority between the band securing type service and the ABR service is set higher in the ABR service.
Conversely, it is also possible to set the bandwidth securing service higher, and in this case the hardware configuration does not require any change.

[0133]

As described above, according to the present invention, the service type to which an arriving cell belongs is identified, the processing content is switched according to the service attribute of the identified cell, and the cell type belonging to each service attribute is switched. When transmission times overlap, priority processing of cell transmission is performed according to the characteristics required for each service, so even if cells with different service attributes are mixed, the characteristics of each service are not impaired. Communication can be performed.

[0134]

[Brief description of the drawings]

[0135]

FIG. 1 is a block diagram showing a conceptual configuration of a first embodiment.

[0136]

FIG. 2 is a block diagram illustrating a basic device configuration of a shaper device.

[0137]

FIG. 3 is a block diagram showing a conceptual configuration of a conventional cell scheduler unit.

[0138]

FIG. 4 is an explanatory diagram showing one configuration of an element constituting the element group shown in FIG. 3;

[0139]

FIG. 5 is a block diagram illustrating a basic device configuration of a cell scheduler unit according to the first embodiment.

[0140]

FIG. 6 is a block diagram illustrating a basic device configuration of a cell scheduler unit according to a second embodiment.

[0141]

FIG. 7 is a diagram illustrating an operation of a cell scheduler unit according to the second embodiment.

[0142]

[Explanation of symbols]

101: Cell scheduler unit, 102: Cell memory (C
M), 103: Free list (FL), 104: Calendar queue (CQ), 105: Output list (O
L), 106: UBR queue (UBRQ), 107: element group, 108: FL pointer, 109: CQ pointer group, 110: output list pointer,
112 ... selector, 113 ... arrival cell signal line, 114
... cell output signal line, 115 ... cell scheduled transmission time signal line, 116 ... cell identification information signal line, 117 ... current time signal line, 119 ... output line, 202 ... cell identification & scheduled transmission time calculation unit, 203: Cell scheduler unit, 204
... clock, 205 ... cell.

Continuation of front page (56) References JP-A-8-213992 (JP, A) JP-A-6-276209 (JP, A) JP-A-7-273773 (JP, A) JP-A-9-36912 (JP, A) JP-A-8-125669 (JP, A) JP-A-9-83525 (JP, A) JP-A-8-97832 (JP, A) JP-A-9-233101 (JP, A) 9-200218 (JP, A) JP-A-9-307566 (JP, A) JP-A-10-56492 (JP, A) JP-A-10-107803 (JP, A) IEICE, Vol. J72-B-I No. 11 p1062-1069 (58) Fields investigated (Int. Cl. ⁷ , DB name) H04L 12/56 H04L 12/28

Claims (2)

(57) [Claims] 1. A traffic shaper device to perform regulation of the output bandwidth of the cell based on the bandwidth restriction request, identifying means for identifying service type belongs arriving cell, the output bandwidth service type belongs arriving cell Secure
If the cell type is
Scheduled transmission time is calculated based on cell output bandwidth parameters
Calculating means, and an output band for each scheduled transmission time calculated by the calculating means.
Of all connections of the service type of
The queuing means for queuing cells and the service type to which the arriving cells belong guarantee output bandwidth.
If the type does not need to be
All service types that do not need to guarantee power bandwidth
Storage method for storing in a common buffer for connections
When the cell transmission time is updated, the updated cell transmission
A cell whose scheduled time is a time or a time earlier than the time
Is queued in the queuing means
Sends the cell and updates the cell sending time or
The cell whose scheduled time is a time earlier than
When not queued in the
A sender that sends the oldest cell stored in the storage means
A traffic shaper device comprising a step . 2. An output bandwidth of a cell based on a bandwidth regulation request.
Identification means for identifying a service type to which an arriving cell belongs in a traffic shaper device for executing the restriction of
And the service type to which the arriving cell belongs secures the output bandwidth.
If the cell type is
Scheduled transmission time is calculated based on cell output bandwidth parameters
A first calculating means to be executed, and a transmission scheduled time unit calculated by the first calculating means,
All connections of the service type of the type that secures the output bandwidth
Queuing means for queuing the cell of the application and the service type to which the arriving cell belongs is only the minimum output bandwidth
If the cell type needs to be guaranteed, the cell arrives
For each cell, the maximum wait time of the cell
A second calculating means for calculating based on the parameter; and a maximum waiting time calculated by the second calculating means.
A type that needs to guarantee only the minimum output bandwidth in units of time
Queuing cells for all connections of a given service type
Second queuing means for transmitting the updated cell when the cell transmission time is updated.
Maximum wait time for time or earlier time
Is queued in the second queuing means.
If it is, the cell is sent and the updated cell is
The maximum wait time can be reached at the time when the file is sent or earlier.
The cell with the active time is queued in the second queuing means.
Cell sending time that has not been updated and has been updated
Or a cell whose scheduled time is earlier than the previous time
The first queuing means
When the cell is sent, the updated cell sending time or
A time earlier than that is set as the maximum wait time.
Is queued by the second queuing means.
And the updated cell transmission time or later
The cell whose previous time is the scheduled transmission time is the first queue.
When the queue is not queued in the
The oldest cell stored in the second queuing means
Traffic means for transmitting traffic.
Kshaper device.