JP2852069B2 - switch - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial applications]

The present invention relates to an optical exchange, and more particularly to an exchange effective for exchanging broadcast signals.

[Prior art]

Asynchronous transfer mode (AT
M) is promising. In this method, a signal is divided into units called cells, information such as a header, which indicates a destination, is added to the beginning of the signal, and the switching is performed by decoding the header by an exchange and distributing the header according to the destination. FIG. 4 shows a configuration example of a conventional exchange. The input signal is written to the input buffer 12, and the destination information is decoded. The control unit 13 operates the switch 14 according to the information.
And sends a signal to a predetermined output interface. As a method for performing one-to-N connection (broadcasting) of TV broadcasting and the like using this ATM exchange, the IEICE Spring National Convention (1989) No. B-394, "1: N in ATM exchange system" Examination of communication path configuration ". FIG. 5 shows the configuration of the exchange shown in the above-mentioned conventional document. In the case of a broadcast type signal, the same signal written and written in the buffer memory 12 on the input side is repeated by the control signal from the cell copy control unit 16 for the number of times of broadcasting (corresponding to N in a one-to-N connection). This is to read and add a header for each destination. The switch 14 decodes the destination and sends a signal to a required output interface.
The transfer processing to each output interface must be completed before the next broadcast signal cell comes. The signal speed that one input interface can handle is the input highway speed.

[Problems to be solved by the invention]

Therefore, in the above-mentioned conventional technique, if the input highway speed is M and the number of broadcasts is N, a signal having a speed of M / N or more cannot be broadcast. The present invention has been made to solve this drawback, and enables broadcasting of signals up to the input highway speed.

[Means for Solving the Problems]

The present invention has means for identifying a broadcast signal on the input side and means for distributing the broadcast signal to the output side. On the output side,
A means for selecting a broadcast signal and a one-to-one connection signal is provided, and means for selecting a received signal based on a signal from the control unit is provided.

[Action]

All output ports are sent a broadcast signal through the distribution means and a one-to-one connection signal to that port through the switch. An output port that requires a broadcast signal selects that signal, while an output port that does not require a broadcast signal selects a one-to-one connection signal. The broadcast signal distribution means can be made to transfer signals up to the capacity of the input highway.
Therefore, signals up to the capacity of the input highway can be broadcast.

【Example】

Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows the configuration of an embodiment of the present invention. The input interface 3 decodes the header information in the input interface 3 and, based on the result, the signal selection circuit 1 identifies the one-to-one connection signal and the one-to-N connection signal and outputs the one-to-N connection signal to the broadcast signal distribution device 2. Transfer to In the broadcast signal distribution device 2 shown in FIG.
The optical signal is converted into an optical signal of wavelength 1 by the optical converter 6, the output signal is divided into the number of output interfaces by the optical splitter 7, and output to the distribution required fiber 8. On the other hand, the signal passing through the switch 4 is sent to the output interface 5 as an optical signal of wavelength 2. As shown in FIG. 3, each output interface is provided with a filter 9 for selecting the wavelength of the light.
The wavelength to which the one-to-one connection signal or the one-to-N connection signal is sent is selected. Here, a filter utilizing an acousto-optic effect is used as a filter for selecting a wavelength. The control is performed as follows. First, the input interface 3 decodes the destination of the broadcast signal from the broadcast information, and the control unit determines a set of output interface numbers to output the broadcast signal based on the destination. This result is sent from the control unit to the wavelength selection filter 9 of the output interface, and the filter selects a required wavelength according to the information. In this embodiment, since a wavelength filter to which an acousto-optic effect is applied is used, the wavelength of light passing therethrough can be changed by changing the frequency of an electric signal input to the filter. Next, the signal is converted into an electric signal by the optical / electrical converter 10 and then written into the output buffer 11. If necessary, the output interface changes the destination information of the header and outputs it. This operation completes the replacement process. In the present embodiment, since optical transmission is used for signal distribution, signal distribution is easy regardless of the number of output interfaces, and waveform deterioration is small. Further, the optical / electrical converter can be used in common for selecting a signal with the variable wavelength filter. FIG. 6 shows an output interface configuration of another embodiment. In this embodiment, both the broadcast signal and the one-to-one connection signal are optically / electrically converted, and both of them are written in the output buffer memory. The necessary signals are selected and output. This selection is made by a control signal from the control unit as in the first embodiment. In this embodiment, a signal distribution by light and a wavelength selection filter are used. However, the present invention is not limited to this, and the same effect can be obtained by electrical distribution and selection.

【The invention's effect】

According to the present invention, it is possible to broadcast signals up to the input highway speed.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of an exchange according to an embodiment of the present invention, FIG. 2 is a block diagram showing a configuration of a broadcast signal distribution device of the above embodiment, and FIG. 3 is an output interface of the above embodiment. FIG. 4 is a block diagram showing a configuration of a conventional exchange, FIG. 5 is a block diagram showing a configuration of a broadcast processing unit of a conventional exchange, and FIG. 6 is another embodiment of the present invention. It is a block diagram which shows the structure of the output part of an example. DESCRIPTION OF SYMBOLS 1... Signal distribution device, 2... Broadcast signal distribution device, 3.
Input interface, 4 ... space division optical switch, 5 ...
... Output interface, 6 ... Electrical / optical switch, 7 ...
Optical splitter, 8 ... fiber, 9 ... wavelength selection filter,
10: optical / electrical exchanger, 11: output buffer, 12: input buffer, 13: switch control unit, 14: space division switch, 15: output buffer, 16: cell copy control unit,
17 …… Header table

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-1-140837 (JP, A) JP-A-2-224548 (JP, A) JP-A-1-256246 (JP, A) IEICE Technology Research Report SS E88-56 (58) Fields investigated (Int. Cl. ⁶ , DB name) H04L 12 / 28,12 / 56 H04L 12/18

Claims (8)

(57) [Claims] 1. An exchange having an input interface, an output interface and a switch network for exchanging bucket signals, means for identifying and separating a signal to be broadcast among input signals, an output interface for transmitting the broadcast signal And a means for selecting the distributed broadcast signal and the signal from the switch network. 2. The exchange according to claim 1, wherein the broadcast signal is converted into an optical signal and distributed. 3. The exchange according to claim 1, wherein an optical switch network is used as a switch network. 4. The exchange according to claim 1, further comprising means for judging whether or not the signal is a broadcast signal from information contained in the input signal and controlling means for selecting a signal based on the result. Exchange. 5. The exchange according to claim 1, wherein when the number of broadcasts is less than a certain value, a normal exchange is performed, and when the number of broadcasts is more than a certain value, it is regarded as a broadcast and said distribution means. An exchange for distributing signals to an output interface. 6. The switching apparatus according to claim 2, wherein said switching means receives a signal from a means for distributing a broadcast signal to an output side interface, and said switching means receives a signal from a switch network. An exchange characterized by comprising a vessel. 7. An exchange according to claim 6, further comprising means for selecting output signals from both said optical and electrical exchangers. 8. An exchange according to claim 6, further comprising means for storing output signals from said optical and electrical exchangers.