JPH0669938A - Data transmitter - Google Patents

Abstract

PURPOSE:To guarantee fairness against a right give up cell by providing a 2nd window counter in the transmitter to permit the use of the right give up cell within a range of a 2nd window size. CONSTITUTION:A cell slot reached from a ring input section 101 to a node is received by a cell reception transfer section 102 is inputted to a cell reception transfer section 102 and a cell relay section 108. The cell reception transfer section 102 analyzes a header part of a cell slot. Simultaneously the cell relay section 108 discriminates a node number and its state of the received cell slot to revise the state of the cell. Furthermore, a state transition management section 109 decides whether the cell relay section 108 sends the cell as it is to a ring output 107 or the cell transmission transfer section 106 inserts data to the cell slot and sends the result to the ring output 107 based on the result of revision of the cell relay section 108 and the state of the 1st and 2nd windows and the presence of data in a transmission buffer to control the operation of the section 108 or 106.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ring-shaped ATM (Asynchronous Transfuse) for unified communication of multimedia information.
er Mode; Asynchronous transfer) A data transmission device in a network.

[0002]

2. Description of the Related Art As a conventional method for a ring access method in a ring-shaped packet transfer network,
Some are used in a ring-shaped packet transfer network (Japanese Patent Application No. 3-107802). A ring access method used in this ring-shaped packet communication network will be described.

FIG. 7 is a diagram showing the configuration of the above ring-shaped packet communication network. Reference numerals 703 to 706 are nodes provided in a ring-shaped network formed of a pair of rings in different directions and communicating via the ring-shaped network. Each node communicates by circulating a fixed-length cell slot on the ring. This cell slot is composed of a 5-byte header section and a 48-byte payload section that carries information. The 5 bytes of the header section include a destination node number, a display bit indicating the state of the cell slot, and the like. It is included. There are three types of cell slot states represented by the display bits, which are an idle state, a use state, and a waiver state, which will be described later.

Reference numeral 707 denotes a network management unit that allocates and manages a band to each node on the network. 701 and 702 are terminal devices connected to the nodes. FIG. 8 is a diagram showing the configuration of the node (data transmission device) in FIG. Reference numeral 801 is a ring input unit which is a transmission path on the receiving side.

Reference numeral 802 denotes a cell reception / transfer unit that extracts the cell from the cell slot if the address of the cell slot input from the ring is checked by checking the header of the cell slot. Reference numeral 803 is a reception buffer that stores the cells extracted by the cell reception transfer unit. Reference numeral 804 is a terminal connected to the node.

A transmission buffer 805 stores cells transmitted from the terminal 804. 806 is a transmission buffer 805
Is a cell transmission / transfer unit that performs a cell transfer process in which a destination is added to a cell stored in a cell slot and transmission is performed in a cell slot. A ring output unit 807 is a transmission path on the transmission side. Reference numeral 808 denotes a cell relay unit that changes the state of the cell and relays it.

Reference numeral 809 is a state transition management unit for managing the state of the cell and managing which state should be transited to which state. A window counter unit 810 counts the number of transmission data. The operation of the ring network configured as above will be described.

Now, consider a case where data is to be transferred from the terminal 701 to the terminal 702 in FIG. Information to be transferred is processed in such a manner that fixed-length packets (hereinafter referred to as cells) are placed in cell slots that circulate in a ring network and transmitted. In transmitting this cell, if the node 704 connected to the terminal 701 uses the cell slots that circulate in a ring shape indefinitely, the ring network is exclusively occupied by specific nodes.
As a result, the inconvenience arises that nodes located between specific nodes cannot communicate. To avoid this, a band is allocated to each node.

When transferring data by connectionless communication, a band is fixedly assigned to each node. On the other hand, when the data is transferred by the connection-oriented communication, the network management unit 707 precedes the data transfer.
Asks you to allocate the required transmission band as follows. Prior to transferring the data of the terminal 701, the node 7
04 notifies the network management unit 707 of the amount of bandwidth required for data transfer, and requests bandwidth allocation (logical call setup). Upon receiving the request, the network management unit 7
07 determines whether the reception is possible or not based on the ring usage status, the amount of bandwidth to which the node has already been allocated, and the like. When the reception is possible, a new band is allocated to the node 704 within a range in which the total band allocated to each node does not exceed the total band of the ring.

Here, the allocated band is the number of cells that a node may transmit out of a predetermined number of cells passing through a node, and allocated band = (unit guaranteed to be used). The number of cells per hour / the number of cells passing through the ring per unit time). In this embodiment, the cell transfer rate of the ring is about 1.4 M cells / second. Now, if the bandwidth allocated to this node is 20 kcells / sec,
Allocation band = 1/70. The node 704 can transfer data using cell slots that circulate on the ring according to the allocated bandwidth amount. Control of the allocated bandwidth is performed by the state transition management unit 809 using the window counter unit 810. The window counter unit 810 counts up once every 70 cell cycles. Then, it counts down once every time a cell is transmitted. If the window counter unit 810 is 1 or more, the window is ON, and if the window counter unit 810 is 0, the window is OFF.

Next, the operation of the node will be described with reference to FIG. When a cell slot that goes around the ring network arrives at a node, each node performs processing such as data reception, relay, and data transmission according to the state of the cell. There are the following three types of cell states. The idle state is a state that is neither used nor abandoned. When a cell in this state arrives, each node can transmit using this cell if the allocated bandwidth remains (when the window is ON). Then, the window counter unit 810 is decremented by one each time it is used.

The usage state is a state in which data is actually transferred. When a cell in this state arrives, each node relays as it is if the destination node number in the header part is addressed to another node, and if it is addressed to the own node, it takes out the data and treats it like the idle state. In the waiver state, the node whose window is ON
It is a cell abandoned when there is no data to send. When a cell in this state arrives, each node can transmit using this cell even if the window is OFF.

In FIG. 8, the cell slot arrived at the node from the ring input section 801 is the cell reception transfer section 80.
2, input to the cell relay unit 808. Cell reception transfer unit 8
Reference numeral 02 analyzes the header portion of the cell slot. When the cell is addressed to its own node and is in use, the cell is taken out from the cell slot and stored in the reception buffer 803. Is not stored in the receive buffer.

At the same time, the cell relay unit 808 determines the destination and status of the input cell slot, changes to the idle state when the node is in use, and changes to the idle state when the node is in use. , If it is in the idle state, it is not changed as it is, and if it is in the state of abandonment, it is not changed as it is.

Further, in response to the change result of the cell relay section 808, the state transition management section 809 determines the cell relay section 808 according to the window state and the presence / absence of data in the transmission buffer.
Determines whether the cell should be sent to the ring output unit 807 as it is, or whether the cell transmission transfer unit 806 should put the data in the cell slot and transmit it to the ring output unit 807, and the control is performed as follows.

(1) When the window is ON and there is data in the transmission buffer, (1.1) If the state changed by the cell relay unit 808 is the use state, the cell relay unit 808 directly transfers the cell to the ring output unit. 807 to send. The reason for relaying as it is is because the cell is addressed to the other node as shown in. (1.2) If the changed state in the cell relay section 808 is the idle state, the cell transmission / transfer section 806 puts data in the cell slot to change the cell to the used cell and causes the ring output section 807 to transmit the data. At this time, the window counter unit 810 is decremented by one. This ensures communication within the band range. (1.3) Cell relay unit 808
If the state changed in (1) is a waiver state, the cell transmission / transfer section 806 puts data in the cell slot, changes the cell to a used cell, and causes the ring output section 807 to transmit the data. At this time, the window counter unit 810 holds the original value.

(2) When the window is ON and there is no data in the transmission buffer, (2.1) If the state changed by the cell relay unit 808 is the use state, the relay is performed as in (1.1). (2.2) If the state changed by the cell relay unit 808 is the idle state, the cell transmission transfer unit 806 directs the cell slot to the own node, puts it in a state of abandonment, and causes the ring output unit 807 to transmit. At this time, the window counter unit 810 is decremented by one. The waiver is
This is to transfer the right to use the cell to other nodes that have exhausted the window. (2.3) If the state changed by the cell relay unit 808 is the waiver state, the cell relay unit 808 causes the cell output unit 807 to send the cell as it is to the ring output unit 807.

(3) When the window is OFF and there is data in the transmission buffer, (3.1) If the state changed by the cell relay unit 808 is the use state, the same as (1.1). (3.2) If the state changed by the cell relay unit 808 is the idle state, the cell relay unit 808 causes the cell to be sent to the ring output unit 807 as it is. (3.3) If the state changed by the cell relay unit 808 is the waiver state, the cell transmission transfer unit 806 causes the ring output unit 807 to transmit the data in the cell slot.

(4) If the window is OFF and there is no data in the transmission buffer, the cell relay unit 808 causes the cell output unit 808 to directly output the cell to the ring output unit 807 regardless of the state changed by the cell relay unit 808. As mentioned above,
The ring access method used in the conventional ring-shaped packet communication network is an idle state as a cell slot state,
It is characterized in that it has three states of use and abandonment. The data transferred in such a packet communication network has a CBR (Continuo
us Bit Rate: Continuous information rate) VBR (Variable Bit Rate), which has the characteristic that a large amount of data arrives temporarily and that the arrival of data is rarely seen at other times (strong burstiness) Variable information rate)
Data etc. This network is guaranteed to use idle cells corresponding to the bandwidth allocated to each node, and is suitable for CBR data transfer.

If the traffic actually input is 60% of the total value of the bandwidth allocated to each node, about 40% of the waiver cells occur on the ring. V with bursty characteristics like computer data
When the BR data is transferred, it may be necessary to temporarily transfer the data equal to or more than the allocated band, but the BR abandonment cell is used for transmission. Since the use of the right release cell is free, even if bursty data is generated at the node, it can be transmitted instantaneously. In this way, the cells on the ring can be used effectively. That is, the usage efficiency of the ring is high.
In this way, the ring access method in the conventional technology is
Bands are mutually exchanged between the nodes by using the cell slot in the right abandoned state to improve the ring usage efficiency.

[0021]

However, according to the prior art, since each node is free to use the cell whose rights have been waived, the fairness (fairness among devices) to the use of the cells whose rights have been waived is not satisfied. ) There was a problem that control was not performed sufficiently. That is, when all the waiver cells are used in the node upstream of a certain node, there is a problem that the waiver cell cannot be used in the node even if the data to be transmitted is accumulated.

In view of the above problems, the present invention provides a ring-shaped packet network communication device (data transmission device) which manages the bands allocated to each node in a distributed manner and realizes a network with high fairness and high ring utilization efficiency. The purpose is to do.

[0023]

SUMMARY OF THE INVENTION In order to solve the above problems, the present invention puts or retrieves data in or from a cell, which is a fixed-length electronic message which is connected in a ring shape via a transmission line and which circulates on the ring. A data transmission device for performing data transmission by means of a cell receiving means for receiving a cell from an input side transmission path, a cell transmitting means for transmitting a predetermined cell to an output side transmission path, and a cell receiving means Cell is in use,
A control unit that determines which of an idle state, an abandoned state, and a reset cell, and performs predetermined transmission / reception control and relay control according to the result, wherein the control unit carries data and transmits. First to count the number of cells
Second permission condition holding means for counting the number of cells transmitted with data when a waiver cell is received.
When the result of discriminating the receiving cell is the idle state, there is data to be transmitted, and the transmission is continued until the count number of the first permission condition holding reaches the allocated cell number. If the cell transmitting means is instructed to transmit the data to be placed in the cell to the used cell and transmit the cell, and if the result of determining the receiving cell is the idle state, there is no data to be transmitted, When the number of holding permission conditions of 1 has not reached the number of allocated cells, the cell transmitting means is instructed to transmit the cells in the state of abandonment of rights, and the result of discriminating the receiving cell is the abandonment of rights. If there is data to be transmitted,
Until the count number for holding the second permission condition reaches a predetermined number, the cell transmitting means is instructed to place the data to be transmitted in the cell and make the cell in the used state and transmit the cell. There is.

If the result of determining the receiving cell is a cell for which the right node is abandoned, the control means further determines:
It may be configured to instruct the transmitting unit to perform transmission as a reset cell and reset the second permission condition holding when the result of discriminating the receiving cell is the reset cell.

After the reset cell addressed to the self node is transmitted, the reset cell addressed to the self node is reset even if the result of discriminating the received cell is the cell in the renounced state addressed to the self node. It may be configured to instruct the transmitting means to transmit in the idle cell instead of the reset cell until the signal is received.

Further, the second permitting condition holding means determines that the received cell is a right-abandoned cell destined for another node, and the data to be transmitted is placed in the cell to be made into a used cell and transmitted. It may be a counter that counts one each time and initializes the count value when the result of discriminating the receiving cell is the reset cell.

[0027]

With the above means, in the data transmission apparatus of the present invention, the cell reception means and the cell transmission means transmit / receive cells on the ring network under the control of the control means.
The cell control means determines the state of the cell, and if the receiving cell is in the idle state or the waived state until the number of cells pre-allocated by the first permission condition holding means is reached, there is data to be transmitted. For example, the cell is put in the used state and the data is loaded and transmitted. In this case, when the received cell is in the abandoned state, the second permitting condition holding means causes the second cell to transmit only until the predetermined number is reached. As a result, it is possible to guarantee fairness with respect to the abandonment cell between the data transmission devices on the ring-shaped packet communication network.

[0028]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of a ring network and its data transmission apparatus of the present invention will be described. The overall configuration of the ring network is the same as that shown in FIG. 7 described in the prior art, and detailed description thereof will be omitted. However, the internal configurations of the packet transfer node devices (data transmission devices) 703 to 706 are different.

FIG. 1 is a block diagram showing the configuration of packet transfer node devices (data transmission devices) 703 to 706. Reference numeral 101 is a ring input unit, which is a transmission path on the receiving side.
A cell reception / transfer unit 102 checks the header of the cell slot input from the ring and extracts the cell from the cell slot if the address is the address in use for the own node.

Reference numeral 103 is a reception buffer, which stores the cells taken out by the cell reception transfer unit. A terminal device 104 is connected to the node. Reference numeral 105 denotes a transmission buffer, which is used by the terminal 10
The transmission cell from 4 is stored. A cell transmission / transfer unit 106 performs a cell transfer process in which a destination is added to the cell stored in the transmission buffer 105 and the cell is placed in a cell slot for transmission.

Reference numeral 107 denotes a ring output, which is a transmission line on the transmission side. A cell relay unit 108 changes the state of the cell and relays it. There are the following four types of states of this cell. (1) The idle state is a state that is neither used nor abandoned. If the band (first window) allocated to the node remains (if the first window is open), the cell in this state may put data in this cell and put it in the used state for transmission. Means that. When a cell in this state arrives, cell relay section 108 does not change the state.

(2) The usage state is a state in which data is actually transferred. When a cell in this state arrives, the cell relay unit 108 relays the destination node number in the header part as it is if the destination node number is addressed to another node, or if it is addressed to the own node, extracts data from the cell reception transfer unit 102 and then enters an idle state. Change to. (3) The relinquished state is a cell that the node in which the first window is open relinquishes when there is no data to send. When a cell in this state arrives, the cell relay unit 108 changes the state to the idle state when it is addressed to its own node, and does not change the state when it is addressed to another node.

(4) The reset state is the state of the cell transmitted by the node that has received the cell in the relinquished state addressed to its own node. Upon receiving this, the cell relay unit 108 changes the state to the idle state when it is addressed to its own node, and does not change the state when it is addressed to another node. In FIG. 1, 109 is a state transition management unit that determines the state of a cell and determines whether or not data can be transmitted, based on the presence / absence of data to be transmitted and the states of the first and second windows, and from which state to which state. It determines whether it should be done and controls the ring access process.

Reference numeral 110 denotes a counter unit, which is a state transition management unit 1.
09 is used to manage the allocated bandwidth. FIG. 2 is a diagram showing a detailed configuration of the counter unit 110. Reference numeral 201 denotes a hunt state display register, which is set when a waiver cell addressed to the own node is received, and indicates that the hunt state is reset when a reset cell addressed to the own node is received and indicates a normal state. It outputs the indicated signal. The hunt state is a period from when a certain node sends out a cell in the reset state addressed to itself to when the node goes around the ring network and receives the reset cell.
The normal state means a state other than the hunt state.

Reference numeral 202 denotes a first window counter (first
(Permission condition holding means) of the first cell transmission signal 20
Every time 5 becomes active, it counts down. The first window counter 202 is used for managing the allocated bandwidth, similarly to the conventional window. Reference numeral 203 denotes a second window counter (second permission condition holding means), which loads a predetermined window size WS when the reset cell reception signal 204 addressed to another node or the right release cell reception signal 210 addressed to the own node is activated, It counts down each time the cell transmission signal 206 of No. 2 becomes active. The second window counter 203 is used for managing the waiver cell. That is, by the state transition management unit 109,
When the second window is ON, data is transmitted using the waiver cell, and when the second window is OFF, the waiver cell is not used.

Reset cell reception signal 204 addressed to another node
Is a signal indicating that a reset cell addressed to another node has been received. Reset cell reception signal 211 addressed to own node
Is a signal indicating that the reset cell addressed to the own node has been received. The first cell transmission signal 205 is a signal given from the state transition management unit 109 and indicating that data has been transmitted in a cell by using the first window, as in the conventional technique.

The second cell transmission signal 206 is a signal that is given from the state transition management unit 109 and indicates that, when a cell in the right abandonment state is received, data is loaded in the cell and transmitted. Reference numeral 207 is a signal indicating the state of the first window, which is active when the first window counter 202 is 1 or more and inactive when 0.

Reference numeral 208 is a signal indicating the state of the second window, which is active when the second window counter 203 is 1 or more and inactive when the second window counter 203 is 0. It Timer 209
Causes the first window counter 202 to count up at the time-out in a cycle corresponding to the reciprocal of the band allocated to the node.

The operation of the ring-shaped network and node device of the present invention configured as described above will be described with reference to FIGS. The cell slot arriving from the ring input unit 101 to the node is the cell reception transfer unit 102,
It is input to the cell relay unit 108. Cell reception transfer unit 102
Analyzes the header part of the cell slot, and when the cell slot is addressed to the terminal connected to its own node and is in use, the cell stored in the payload part of the cell slot is stored in the reception buffer 103. Store in the other case, and do not store in the receive buffer otherwise.

At the same time, the cell relay section 108 determines the node number and state of the input cell slot and changes the cell state. "State of reception cell slot" in Figure 3
The column of “result of change of cell relay section” shows the states before and after the change by the cell relay section 108. Further, FIG. 4 shows a state transition diagram showing cell state transitions by the cell relay unit 108 in the reception processing. In the figure, the symbol && means "Katsu", and the symbol * means "don't care".

Specifically, the cell relay section 108 changes as follows. The following-corresponds to the "reception cell slot status" column in FIG. Specifically, the cell relay unit 108 changes as follows. When the reception cell is in use, it is in the idle state if it is addressed to its own node, and it is not changed if it is addressed to another node.

If the receiving cell is idle, it does not change. It is not necessary to distinguish between the own node and other nodes. When the receiving cell is in the state of abandonment and is addressed to its own node, the operation differs between the normal state and the hunt state. First, in the normal state, the cell relay unit 108 changes to the reset state. At this time, the cell relaying unit 108 outputs the right node abandonment cell reception signal 210 shown in FIG. 2, which initializes the second window counter 203 (the value of the window size WS is loaded). At the same time, the hunt status display register 201 is set by the reception signal 210 of the abandoned right cell addressed to the own node, and the hunt status is entered. Next, in the hunt state, the cell relay unit 10
8 changes the cell in the right renunciation state addressed to its own node to the idle state. This hunt state is provided in order to avoid sending the reset cells again in duplicate when a right-abandoned cell addressed to the own node is received immediately after sending the reset cells. The operation in the hunt state differs from that in the normal state only in the case of.

On the other hand, if the receiving cell is in the state of abandonment and is addressed to another node, it is not changed. If the receiving cell is in the reset state and addressed to its own node, change to the idle state. At this time, since the cell is in the hunt state, the cell relay unit 108 outputs the reset cell reception signal 211 addressed to its own node shown in FIG. 2, whereby the hunt state display register 201 is reset, and the hunt state returns to the normal state. On the other hand, if the receiving cell is in the reset state and is addressed to another node, it is not changed. This is because the reset cell goes around the ring network. At this time, the cell relay unit 108 outputs the reset cell reception signal 204 addressed to the other node shown in FIG. 2, thereby initializing the second window counter 203 (the predetermined value of the window size WS of the second window is Loaded).

Further, according to the change result of the cell relay unit 108, the state transition management unit 109 causes the cell relay unit 108 to directly change the cell according to the states of the first and second windows and the presence / absence of data in the transmission buffer. Should be sent to the ring output 107 or the cell transmission / transfer section 106 should place data in the cell slot and send it to the ring output 107, and control the operation.

FIG. 3 shows states such as “result of change of cell relay section”, “window and queue state”, “transmission cell slot” and the like, which represent the control operation of the state transition management section 109. Further, FIG. 5 shows a state transition diagram showing a state transition of the cell under the control of the state transition management unit 109. In the figure, symbol &&
Stands for "and", the symbol # stands for "or", and the bracketed symbols [] stand for "counted down window counter".

Specifically, the state transition management unit 109 controls as follows. The following-corresponds to the "cell relay unit change result" column in FIG. State transition management unit 109
When the cell state is changed by the cell relay unit 108, the open / close of the first and second windows (W1 and W2 in FIG. 3) is determined, and the transfer buffer 105 (queue Q in FIG. 3) waits for transfer. Cell is determined. As a result, the operation is divided, and for convenience of description, the case will be described separately (see FIG. 3).

If the state changed by the cell relay unit 108 is the use state, the cell relay unit 108 sends the cell to the ring output 107 as it is. The reason for relaying as it is is because the cell is addressed to the other node as shown in. When the state changed by the cell relay unit 108 is the idle state. In this case, the same operation as the conventional technique is performed regardless of the value of the second window (W2). That is, first, when the first window is open (W1> 0), if the transmission buffer 105 has data (Q> 0), the state transition management unit 109 loads the data from the cell transmission transfer unit 106 to the usage state. Send the cell. At this time, the state transition management unit 109 outputs the first cell transmission signal 205, and the first window counter 202 counts down by one (W1 becomes W1-1).

Next, when W1> 0 and Q = 0, the cell transmission transfer unit 106 causes the ring output 107 to transmit the cell in the right relinquished state addressed to the own node. At this time, the state transition management unit 109 outputs the first cell transmission signal 205,
The first window counter 202 counts down by one (W1 becomes W1-1). Finally, with W1 = 0,
When Q = 0, the cell relay unit 108 causes the ring output 107 to directly transmit the idle cell. At this time, the first and second window counters 202 and 203 do not change.

When the state changed by the cell relay unit 108 is the reset state, the cell relay unit 108 transmits the cell in the reset state to the ring output 107 as it is. At this time, if the cell is in the reset state addressed to its own node, as described above, the hunt status display register 201 has already been set by the reception signal 210 of the right node abandoned cell addressed to the own node from the cell relay unit 108 and the hunt state display register 201 has been set. The second window counter 203 is reset. On the other hand, even in the case of a cell in a reset state addressed to another node, the second window counter 203 has already been reset by the other-node addressed reset cell reception signal 204 from the cell relay unit 108 as described above. .

When the state changed by the cell relay unit 108 is the right waiver state, regardless of the first window,
The second window, depending on the state of the send buffer 105,
The behavior is different. First, when W2> 0 and Q> 0,
The cell transmission / transfer section 106 causes the cell in use to carry data to be transmitted. At this time, the state transition management unit 109 outputs the second cell transmission signal 206, and the second window counter 203 counts down by one (W2 is W2.
-1). Next, when W2 = 0 or Q = 0, the cell relay unit 108 transmits the cell in the reset state to the ring output 107 as it is. At this time, if Q> 0, the waiver cell has already been used for the window size WS of the second window, so the use of the waiver cell is prohibited by itself and the waiver cell is given to the downstream node. It will be. As a result, it is possible to secure fairness (fairness) between the nodes regarding the use of the waiver cell.

As described above, the cell state is changed by the cell relay unit 108 in the reception process (FIG. 4), and further changed by the control of the state transition management unit 109 in the transmission process (FIG. 5). It takes place in two stages. FIG. 6 shows a combination of the state transition diagram of FIG. 4 and the state transition diagram of FIG. FIG. 6 shows a state transition state focusing on the reception cell and the transmission cell of the node. In the figure, the cell in the waived state is transmitted to the cell in the used state using the cell only when the second window W2 is open (W2> 0). In addition to the introduction of cells in the reset state, fairness is ensured for the use of cells in the waived state.

[0052]

As described above, according to the data transmission apparatus of the present invention, since the second window counter is provided, and the use of the right waived cell is permitted within the range of the second window size, There is an effect that it is possible to guarantee fairness for a waiver cell between data transmission devices on the ring-shaped packet communication network. Specifically, while the number of cells that can be sent out is guaranteed by the first window as in the case of CBR transmission as in the conventional case, the present invention is also applicable to the case of strong bursty data transmission such as packet data. Since the fairness guarantee of ring access can be performed by the window of 2,
It is also suitable for connectionless communication.

[Brief description of drawings]

FIG. 1 is a block diagram of a data transmission device according to an embodiment of the present invention.

FIG. 2 is a block diagram of a counter unit of the data transmission device in the embodiment.

FIG. 3 is a diagram showing a relationship between cell state transitions, first and second windows, and a transmission buffer state in the data transmission apparatus in the embodiment.

FIG. 4 is a state transition diagram of cells from the reception to the cell relay unit in the embodiment.

FIG. 5 is a state transition diagram of cells from the cell relay unit to transmission in the embodiment.

FIG. 6 is a cell state transition diagram showing an interconnection between a reception cell and a transmission cell in the embodiment.

FIG. 7 is a diagram showing a configuration of a ring-shaped packet communication network in a conventional example.

FIG. 8 is a node device (data transmission device) in a conventional example.
It is a block diagram of.

[Explanation of symbols]

101 ring input unit 102 cell reception transfer unit 103 reception buffer 104 terminal device 105 transmission buffer 106 cell transmission transfer unit 107 ring output unit 108 cell relay unit 109 state transition management unit 110 counter unit 201 hunt state display register 202 first window counter (First permission condition holding means) 203 Second window counter (second permission condition holding means) 204 Reset cell reception signal for other node 205 First cell transmission signal 206 Second cell transmission signal 207 First Signal indicating window state 208 Signal indicating second window state 209 Timer 210 Self-node addressed cell with abandoned cell reception signal 211 Self-node addressed reset cell signal reception signal

Claims (4)

[Claims] 1. A data transmission device, which is connected via a transmission line in a ring shape and carries out data transmission by loading or retrieving data in a cell which is a fixed-length electronic message that circulates on the ring. The cell receiving means for receiving cells from the channel, the cell transmitting means for transmitting a predetermined cell to the transmission path on the output side, and the cell received by the cell receiving means are in the used state, the idle state, the abandoned state, and the reset cell. A first permission for counting the number of cells in which data is transmitted, and a control unit that determines which of the cells is transmitted and performs predetermined transmission / reception control and relay control according to the result. The condition holding means, the second permission condition holding means for counting the number of cells carrying data when the waived cell is received, and the result of discriminating the receiving cell is in the idle state. In case,
Cell transmitting means includes data to be transmitted, and data to be transmitted is placed in a cell to be made into a used cell and transmitted until the count number of holding the first permission condition reaches the assigned cell number. If the result of discriminating the receiving cell is idle,
When there is no data to be transmitted and the count number of the first permission condition holding does not reach the allocated cell number,
When the cell transmission means is instructed to transmit in a cell in a waived state and the result of determining the receiving cell is the waived state,
Until there is data to be transmitted and the count number for holding the second permission condition reaches a predetermined number, the cell transmitting means is instructed to place the data to be transmitted in a cell and make the cell in a used state and transmit the cell. A data transmission device characterized by instructing by means of. 2. The control means further instructs the transmission means to perform transmission as a reset cell when the result of discriminating the reception cell is a cell in the right renunciation state addressed to the own node, and the reception cell If the result of determining is a reset cell,
The data transmission device according to claim 1, wherein the holding of the second permission condition is reset. 3. The control means further resets, after transmitting the reset cell addressed to its own node, even if the result of discriminating the receiving cell is a cell in a state of abandoned rights addressed to its own node. 3. The data transmission device according to claim 2, wherein the data transmission device is instructed to transmit the idle cell instead of the reset cell until the cell is received. 4. The second permitting condition holding means determines that a receiving cell is a result of a right abandonment cell addressed to another node, and puts data to be transmitted on the cell to make it a used cell and transmits the cell. 2. The data transmission device according to claim 1, wherein the data transmission device comprises a counter that counts one for each cell and initializes the count value to a predetermined value when the result of discriminating the reception cell is a reset cell.