JP2924446B2 - ATM terminal adapter - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an ATM (Asynchr).
More particularly, the present invention relates to an ATM terminal adapter for connecting a data transfer device having a variable data transfer rate to an ATM network.

[0002]

2. Description of the Related Art A conventional ATM terminal adapter includes a cell circuit for converting data from a data transfer device into ATM cells and sending the data to an ATM network, a reception cell buffer for temporarily storing ATM cells received from the ATM network, and an ATM cell buffer. It had only an ATM reassembly circuit that reassembled the cells into data.

[0003]

In the conventional ATM terminal adapter, when the sending terminal adapter cannot know the use state of the receiving buffer on the receiving side, the receiving cell buffer of the receiving terminal adapter becomes insufficient. The data cells that have already been transmitted from the transmitting terminal into the ATM network are discarded, and even if the receiving terminal immediately sends a transmission suppression signal to the transmitting terminal, the transmitting terminal does not propagate the propagation delay in the ATM network. As a result, the transmission suppression signal is received with a time delay, and there is a problem that the flow control cannot be performed in a sufficiently short time.

[0004]

According to the present invention , in an ATM terminal adapter for connecting an ATM network between data transfer devices having variable data transfer rates, a receiving terminal adapter stores data in a receiving cell buffer. Monitor the amount of cells
When the storage cell amount increases, the count-up request cell
When the amount of stored cells decreases, a count
A reception buffer monitoring circuit for outputting a
Read data cell from receive cell buffer and convert to data
A cell reassembly circuit to be assembled,
Data from the data transfer device into cells.
A cell circuit for assembling and sending to the ATM network;
When a count-up request cell is received,
When the countdown request cell is received,
The cell counter that goes down and the cell counter
Article set in advance by the count value to be input
Average and peak cell delivery rates
And a cell transmission circuit for performing flow control for
ATM terminal adapters, wherein the Ru obtained.

[0005]

[0006]

Next , the present invention will be described with reference to the drawings. Figure 1 is a machine <br/> functional block diagram of one embodiment of an ATM terminal adapter of the present invention.

In order to connect the transmission terminal 10 and the receiving terminal 20 and through the ATM network 50, the transmitting terminal adapter 30
And the receiving-side terminal adapter 40. In this embodiment,
Only one-way data transfer from the transmitting terminal 10 to the receiving terminal 20 is described.

The transmitting terminal adapter 30 is a
1, transmit cell buffer 32 is constituted by a cell counter 33 and a cell sending circuit 34, the receiving terminal adapter 4
Reference numeral 0 denotes a reception cell buffer 41, a cell reassembly circuit 42, and a reception buffer monitoring circuit 43.

Next, the data transfer operation in this embodiment will be described. The receiving terminal adapter 40 is the ATM network 5
A data cell from 0 is input and stored in the reception buffer 41. The reception buffer 41 outputs the amount of cells stored therein. The cell reassembly circuit 42
Reading, to restore the data passed to the receiving terminal 20. What reception buffer monitoring circuit 43 reads the cell storage amount output from the receiving buffer 41, when the accumulation amount of the cell is increased
Decrease the count-up request cell and accumulation of cells
Outputs, respectively Re their <br/> the ATM network 50 to count down request cell upon.

In the ATM network 50, the transmitting terminal adapter 30
And outputting the cell inputted to the receiving terminal adapter 40 from Oh token operations cells input from the receive buffer monitoring circuit 43 to output to the transmission side terminal adapter 30
Rakaji Me path has been set.

[0011] In the transmitting terminal adapter 30, the transmitting terminal 1
The transmission data from 0 is input to the celling circuit 31. The celling circuit 31 assembles transmission data into cells and inputs the cells into the transmission cell buffer 32. The transmission cell buffer 32 outputs this data cell to the ATM network 50. Cell counter 33
It receives the token operations cell output by the receiving terminal adapter 40 and through the ATM network 50 counts up when receiving the count-up request cell and counts down when it receives the countdown request cell
Each count value is output. Cell sending circuit 34 monitors the count value input from the cell counter 33 in the transmission buffer 32, the flow to vary the average speed and the peak rate of the cell transmission by condition has been set Me beforehand according to the count value Transmission cell buffer 3 for control signal
Enter 2 That is, the transmission cell buffer 32 by the flow control signal when the count value of the cell counter 33 becomes large to reduce the average rate and peak rate of cell transmission, also to increase the average speed and the peak velocity of the cell transmission when the count value decreases. Further, the transmission cell buffer 32 transmits a write disable signal to the transmission terminal 10 when cells cannot be transmitted to the ATM network 50.

[0012]

As described above, the present invention relates to an ATM terminal adapter for connecting an ATM network between data transfer devices having variable data transfer rates, wherein the receiving terminal adapter is a storage cell in a reception cell buffer. Monitor quantity and store
When the number of accumulated cells increases, a count-up request cell is issued.
When the amount of stored cells decreases, the countdown request
Buffer monitoring circuit that outputs
Cells that read data cells from the
With reassembly circuit, the transmitting terminal adapter transfers data
ATM network by assembling data sent from equipment into cells
And a cell-counting circuit that sends the count-up request cell
Counts up and counts down when receiving
A cell counter that counts down when it receives
Depending on the count value output by this cell counter,
The average cell transmission speed and
Transmission that performs flow control that changes the peak speed
The Rukoto a circuit, since the transmitting terminal adapter is so as to suppress the transmission number of data cells in accordance with the storable number of cells know received cell buffer use state of the reception cell buffer, the receive buffer overflows the can be prevented beforehand <br/> Me has the effect of allowing flow control is hardly affects the propagation delay of the ATM network.

[Brief description of the drawings]

FIG. 1 is a functional block diagram of an embodiment of an ATM terminal adapter of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Sending terminal 20 Receiving terminal 30 Sending terminal adapter 31 Celling circuit 32 Sending cell buffer 33 Cell counter 34 Cell sending circuit 40 Receiving terminal adapter 41 Receiving cell buffer 42 Cell reassembly circuit 43 Receiving buffer monitoring circuit 50 ATM network

Continuation of the front page (56) References JP-A-62-290241 (JP, A) JP-A-62-290244 (JP, A) JP-A-3-247056 (JP, A) JP-A-62-290242 (JP) JP-A-57-173255 (JP, A) JP-A-62-296640 (JP, A) JP-A-62-98944 (JP, A) JP-A-64-39853 (JP, A) 4-369169 (JP, A) (58) Field surveyed (Int. Cl. ⁶ , DB name) H04L 12/56 H04L 12/28 H04L 29/08

Claims (1)

(57) [Claims] 1. An ATM terminal adapter for connecting an ATM network between data transfer devices having variable data transfer speeds, wherein a receiving terminal adapter is provided in a receiving cell buffer.
When the storage cell amount is monitored and the storage cell amount increases,
Outputs a count-up request cell and reduces the amount of stored cells
When a receive buffer that outputs a countdown request cell
And a data cell from the reception cell buffer.
And a cell reassembly circuit that reads out
The transmitting terminal adapter sends the data from the data transfer device.
Assembled data is assembled into cells and transmitted to the ATM network.
Receiving the count-up request cell
Counts up and countdown request cell
A cell counter that counts down when it receives
Depending on the count value output by this cell counter,
The average cell transmission speed and
Transmission that performs flow control that changes the peak speed
ATM terminal adapter, characterized in that it comprises a circuit.