JPH07336361A - Atm network and network constituting device - Google Patents

Abstract

PURPOSE:To provide an ATM network and a network constituting device for transferring ATM cells without abandonment by transmitting multiplexed cells on an output line with a prescribed time interval. CONSTITUTION:The cells 4 inputted from plural input lines 5 are multiplexed in the multiplex circuit 6 of a multiplexer 1. Then, by a shaper 7, the cells 4 are transmitted to the output line 8 with a cell transmission interval equivalent to the total sum of the peak rates of respective connections set on the output line 8. Thus, the cells 4 inputted to this network constituting device are multiplexed and transmitted to the output line 8 with the time interval decided based on the total sum of bands allocated to the respective connections set on the output line 8. Thus, in this asynchronous communication (ATM) network constituted of the network constituting device, cell abandonment to buffer overflow is completely suppressed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ATM network and a network constituent device, and more particularly to an ATM which transfers ATM cells without discarding.
The present invention relates to a network and a network constituent device.

[0002]

2. Description of the Related Art In an ATM (asynchronous communication) network, information is decomposed into fixed lengths and information for identifying a virtual line connecting a connection, that is, a sender / receiver is added to the ATM cell (hereinafter referred to as a cell). Is generated and multiplexed / converted in units of this cell to form a communication network. FIG. 7 is a block diagram showing a configuration of a general ATM network. In FIG. 7, 11 is a multiplexer for time division multiplexing cells input from a plurality of incoming lines, and 13 is a plurality of incoming lines. A cross-connect / exchange device for switching and connecting cells to a predetermined output line, and a separation device 12 for separating and outputting cells input from an input line to a plurality of output lines.

Conventionally, each network constituent device which constitutes such an ATM network comprises a buffer for temporarily storing cells, and a multiplex circuit and a demultiplexer circuit for guiding cells input from an incoming line to a predetermined outgoing line. Was configured. FIG. 8 is a block diagram showing a multiplexer 11 of the conventional network constituent devices. In FIG. 8, 6 is a multiplexing circuit for time-division multiplexing cells 4 input from a plurality of incoming lines 5 and 10 is a multiplexing circuit. It is a buffer that temporarily stores the cells 4 multiplexed by 6 and outputs them to the output line 8. FIG. 9 is a block diagram showing a separation device 12 of the conventional network constituent devices. In FIG. 9, 9 is a separation circuit for separating and outputting the cells 4 input from the incoming line 5, and 10 is a separation output from the separation circuit 9. It is a buffer that temporarily stores each of the generated cells 4 and outputs them to each outgoing line 8.

FIG. 10 is a block diagram showing a cross-connecting / switching device 13 of the conventional network components, 6 is a multiplexing circuit for time-division multiplexing cells 4 input from each incoming line 5, and 9 is a multiplexing circuit. A separation circuit 10 that separates and outputs the cells 4 from 6 is a buffer that temporarily stores the cells 4 that are separated and output from the separation circuit 9 and outputs them to each output line 8. FIG. 11 is a block diagram showing another example of the cross-connecting / switching device 13 of the conventional network components, 6 is a multiplexing circuit for time-division multiplexing cells 4 input from each incoming line 5, and 10 is a multiplexing circuit. A buffer for temporarily storing the cell 4 from the circuit 6 and a separation circuit 9 for separating and outputting the cell 4 from the buffer 10 to each output line 8.

Of these network constituent devices, the multiplexing device 11 of FIG. 8 and the cross-connect / switching device 1 of FIG.
3, the cell 4 output from the multiplexing circuit 6 is the buffer 1
0 is sequentially written, and in the separation device 12 of FIG. 9 and the cross-connect / exchange device 13 of FIG.
The cells 4 separated and output from the buffer 10 are sequentially written into the respective buffers 10, and as long as the cells 4 are accumulated in the buffers 10, the cells 4 are continuously read from the buffer 10 and output to the output line 8 or the separation circuit 9. When the buffer 10 has no free area, the input cell 4 is discarded, and the cell is discarded due to the overflow of the buffer.

[0006]

Therefore, in such a conventional ATM network and network constituent device, as long as the cells 4 are stored in the buffer 10, the cells 4 are continuously read and transmitted. For this reason, the cells 4 may be in a densely packed state on the incoming line of the network-forming device in the subsequent stage, and may continue to be sent out. If the transmission capacity of the outgoing line exceeds the transmission capacity of the outgoing line instantaneously, it becomes impossible for the buffer 10 to absorb the difference, and there is a problem that cells are discarded due to overflow of the buffer. The present invention is intended to solve such a problem, and an object of the present invention is to provide an ATM network and a network constituent device capable of completely suppressing the occurrence of cell discard due to overflow of a buffer.

[0007]

In order to achieve such an object, a network construction apparatus according to the present invention is a network construction apparatus that multiplexes cells input from a plurality of incoming lines and sends them out to an outgoing line. The cells are transmitted to the outgoing line at time intervals determined based on the sum of the bandwidths allocated to the connections set on the line. Further, in the network constituent device that separates the cells input from the incoming lines and sends them to the plurality of outgoing lines respectively, the time determined based on the sum of the bandwidths allocated to the respective connections set on the outgoing lines. At intervals, cells are sent to each outgoing line.

Further, in a network constituent device which exchanges cells input from a plurality of incoming lines and sends them out to a predetermined outgoing line, the sum of the bandwidths allocated to the respective connections set on the outgoing lines is calculated. A cell is sent to each outgoing line at a time interval determined based on the above. further,
The ATM network includes at least one of the above-mentioned network constituent devices.

[0009]

Therefore, the cell input to the network constituent device is
It is multiplexed, demultiplexed, or exchange-connected, and is transmitted on the outgoing line at a time interval determined based on the sum of bands allocated to the respective connections set on the outgoing line.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing a multiplexing device in a network configuration device according to an embodiment of the present invention. In FIG. 1, the same or similar parts as those described above are designated by the same reference numerals. Figure 1
In the figure, reference numeral 1 is a multiplexing device composed of a multiplexing circuit 6 and a shaper 7 for outputting the cells 4 from the multiplexing circuit 6 at a predetermined transmission interval. Here, cell discard due to overflow of the buffer will be described. Proceedings of 1993 International Conf
erence on Communications, pp.1389-1403), the following facts regarding cell disposal are proved.

Now, consider a case where cells respectively transmitted from a plurality of cell transmission sources 1 to N are multiplexed on one link. When the peak value of the cell transmission rate at each of these cell transmission sources 1 to N, that is, the peak rate is given by p1, p2, ..., PN, respectively, when the cell transmission rate C of the link and the cell are multiplexed. Buffer size K
When the conditions of p1 + p2 + ... + pN ≤C K ≥N are satisfied with respect to (the number of memory cells), the cell discard rate becomes 0.

In order to apply this theorem to an actual ATM network and eliminate cell discard due to overflow of the buffer, first, the peak rate given to the incoming line is kept on the incoming line of the network constituent device. This means that cells are being transmitted on the outgoing line of the network constituent device of the preceding stage while keeping a predetermined peak rate for the outgoing line. This peak rate corresponds to the maximum read speed from the buffer to the outgoing line, but according to the above theorem, even if it is reduced to the sum of the peak rates of the connections set on the outgoing line, the cell The discard is “0”. Therefore, in the buffer provided on the outgoing line of each network constituent device, the buffer size should be equal to or more than the total number of incoming lines, and the peak value of the read speed on the outgoing line should be the sum of the peak rates of the connections set on the outgoing line. By controlling in this way, it is possible to completely prevent cell discard due to buffer overflow in the ATM network composed of these network components.

5 and 6 are block diagrams showing a shaper 7 for outputting cells at predetermined intervals. In FIG.
Reference numeral 0 is a buffer for temporarily storing the cell 4, 11 is a control circuit for controlling writing or reading of the cell 4 to and from the buffer 10, and in this case, the buffer size of the buffer 10, that is, the number of storable cells is the shaper 7.
It is set to be equal to or more than the total number of incoming lines of the network constituent device used by itself. In FIG. 5, cells 4 are sequentially written in the buffer 10 and the shaper 7 is controlled by the control circuit 11.
The cells 4 corresponding to the respective outgoing lines are read out at a sending interval corresponding to the sum of the peak rates of the respective connections set for the outgoing lines of the network constituent device used by itself.

Further, in FIG. 6, the cells input by the control circuit 11 at the transmission intervals corresponding to the sum of the peak rates of the respective connections set to the respective outgoing lines of the network constituent device in which the shaper 7 itself is used. 4 is written in the buffer 10, and the cell 4 is cyclically searched and read from the buffer 10 including the empty area at the transmission speed of the outgoing line. Therefore, in FIG. 1, cells 4 input from a plurality of incoming lines 5 are input.
Is time-division multiplexed by the multiplexing circuit 6 and is input to the shaper 7, from which it is transmitted to the output line 8 at a transmission interval corresponding to the sum of the peak rates of the connections set in the output line 8.

FIG. 2 is a block diagram showing a separating device in the network constituting device according to one embodiment of the present invention. In FIG. 2, the same or equivalent parts as those described above are designated by the same reference numerals. In FIG. 2, reference numeral 2 is a separation device including a separation circuit 9 and a plurality of shapers 7 that output the cells 4 from the separation circuit 9 at a predetermined sending interval. The cell 4 input from the input line 5 is separated by the separation circuit 9 and input to the corresponding shaper 7, and the output rate 8 of the peak rate of each connection is set to the corresponding output line 8 from each shaper 7. It is sent to each outgoing line 8 at a sending interval corresponding to the sum.

FIG. 3 is a block diagram showing a cross-connecting / switching device in the network-constituting device which is an embodiment of the present invention. In FIG. 3, the same or equivalent parts as those described above are designated by the same reference numerals. is there. In FIG. 3, 3 is a multiplex circuit 6
And a separation circuit 9 and a plurality of shapers 7 that output the cells 4 from the separation circuit 9 at predetermined transmission intervals. The cells 4 input from the plurality of incoming lines 5 are multiplexed by the multiplexing circuit 6 and the demultiplexing circuit 9.
It is separated and input to the corresponding shaper 7, and is sent from each shaper 7 to each outgoing line 8 at a sending interval corresponding to the sum of the peak rate of each connection set to the corresponding outgoing line 8 for each outgoing line 8. To be done.

FIG. 4 is a block diagram showing another cross-connecting / switching device among the network components which is an embodiment of the present invention. In FIG. 4, the same or equivalent parts as those described above are designated by the same reference numerals. I am doing it. In FIG. 4, reference numeral 3 is a cross-connect / switching apparatus composed of a multiplexing circuit 6, a separation circuit 9, and a plurality of shapers 7 for outputting the cells 4 from the separation circuit 9 at a predetermined transmission interval. The cells 4 input from a plurality of incoming lines 5 are time-division multiplexed by the multiplexing circuit 6 and are input to the shaper 7, and the cells 4 corresponding to the respective outgoing lines 8 are set to the outgoing line 8 and the peak of each connection is set. It is sent from the shaper 7 to the separation circuit 9 at a sending interval corresponding to the sum of the rates, separated by the separation circuit 9 and sent to the corresponding outgoing line 8.

[0018]

As described above, according to the present invention, cells input from incoming lines are multiplexed, demultiplexed or exchange-connected, and determination is made based on the sum of bandwidths allocated to the respective connections set on outgoing lines. Since the data is sent out on the outgoing line at a time interval that is set, it is possible to prevent the cell arrival speed to the outgoing line of the network constituent device in the subsequent stage from instantaneously exceeding the transmission capacity of the outgoing line. ATM using network configuration device
By constructing the network, it is possible to completely prevent the cell discard due to the overflow of the buffer, which is a remarkable effect.

[Brief description of drawings]

FIG. 1 is a block diagram of a multiplexer according to an embodiment of the present invention.

FIG. 2 is a block diagram of a separation device according to an embodiment of the present invention.

FIG. 3 is a block diagram of a cross-connect / exchange device according to an embodiment of the present invention.

FIG. 4 is a cross-connect / according to another embodiment of the present invention.
It is a block diagram of an exchange device.

FIG. 5 is a block diagram of a shaper according to an exemplary embodiment of the present invention.

FIG. 6 is a block diagram of a shaper according to another embodiment of the present invention.

FIG. 7 is a block diagram showing a general ATM network.

FIG. 8 is a block diagram of a conventional multiplexer.

FIG. 9 is a block diagram of a separation device according to a conventional example.

FIG. 10 is a block diagram of a cross-connect / exchange device according to a conventional example.

FIG. 11 is a cross-connect / according to another conventional example.
It is a block diagram of an exchange device.

[Explanation of symbols]

1 ... Multiplexing device, 2 ... Separation device, 3 ... Cross-connect /
Switching device, 4 ... Cell (ATM cell), 5 ... Incoming line, 6 ... Multiplexing circuit, 7 ... Shaper, 8 ... Outgoing line, 9 ... Separation circuit, 10
... buffer, 11 ... control circuit.

Claims (4)

[Claims] 1. A network configuration device for multiplexing cells input from a plurality of incoming lines and transmitting the multiplexed cells to an outgoing line, which is determined based on a sum of bands allocated to each connection set on the outgoing line. A network configuration device, wherein the cell is transmitted to the outgoing line at time intervals. 2. A network constituent device for separating a cell input from an incoming line and sending it to a plurality of outgoing lines respectively, based on a sum of bands allocated to each connection set on each outgoing line. A network configuration device, wherein the cell is transmitted to each of the outgoing lines at a determined time interval. 3. A network constituent device for switching and connecting cells input from a plurality of incoming lines and sending the cells to a predetermined outgoing line, based on a sum of bands allocated to each connection set on each outgoing line. At a time interval determined by
A network configuration device, wherein the cell is transmitted to each of the outgoing lines. 4. An ATM network comprising at least any one of the network constituent devices according to claims 1 to 3.