JP2636569B2 - Line switching device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is applied to a line switching device for redundant transmission and reception transmission lines. In particular, the present invention relates to a line switching device for a control system signal which is used for communication between sections of an optical transmission device and is transmitted while being superimposed on a section overhead added to a main signal. Suitable for use in North American optical transmission equipment.

[0002]

2. Description of the Related Art FIG. 6 is a block diagram of a conventional line switching device.

Conventionally, as shown in FIG. 6, a line switching apparatus includes a transmission circuit 1 on a transmission side and transmission transmission line interfaces 6A and 6B for interfacing with two sets of transmission lines.
, Branching circuit 21, receiving transmission line interfaces 17A and 17B on the receiving side, and transmission line state monitoring circuit 31
A, 31B, a switching control circuit 32, a selection circuit 33, and the reception circuit 12.

Next, the operation will be described.

On the transmission side, the transmission circuit 1 sends out the generated signal to both transmission lines by the branch circuit 21 through the working and protection transmission line interfaces 6A and 6B. On the receiving side, there are independent transmission line state monitoring circuits 31A and 31B for each transmission line, and the switching control circuit 32 determines a transmission line to be used based on the detection result. The two transmission path signals are both input to the selection circuit 33, and the selection circuit 33 delivers the selected signal to the reception circuit 12 according to the control signal from the switching control circuit 32.

[0006] The same applies to the reverse direction.

[0007]

However, in such a conventional line switching device, the wiring for connecting the transmission circuit to the transmission line interface for transmission and the wiring for connecting the reception circuit to the transmission line interface for reception are not provided. Are required independently of each other, and each transmission line has an independent line state monitoring circuit, and complicated line switching control is required. Therefore, there has been a problem that the circuit scale on the receiving side becomes particularly large. Further, since the configurations of the transmitting unit and the receiving unit are different, there is a problem that the transmitting unit and the receiving unit are required independently at both ends.

SUMMARY OF THE INVENTION The present invention solves the above-mentioned drawbacks, and a line switching apparatus which can share a connection medium between a transmission circuit on a transmission side and a reception side and a reception circuit and a transmission line interface and can reduce the circuit scale. The purpose is to provide.

[0009]

According to the present invention, there is provided a transmitting circuit for transmitting a signal to a destination on the transmitting side and a receiving side, and an active and standby interface serving as an interface between the transmitting circuit and the active and standby transmission lines. A transmission line interface for transmission, a reception circuit for receiving a signal from the transmission circuit of the other party, and a working circuit as an interface with the working and protection transmission lines respectively connected to the working and protection transmission line interfaces of the other party. And a backup transmission line interface comprising: a transmission / reception bus interface connected to the transmission circuit and the reception circuit on the transmission side and the reception side, respectively; The working bus interface connected to the A spare bus interface connected to the transmission transmission line interface and the reception transmission line interface, and a bidirectional bus network for connecting the transmission / reception, working and protection bus interfaces, and each of the working and protection buses The interface has a predetermined address, and each of the transmitting circuits includes means for adding an address of a bus interface designated by the transmitting circuit to a signal to be transmitted.

Further, in the present invention, the signal may be a control signal which is transmitted by being superimposed on a transmission path for a main signal.

The main signal disconnection detection circuit and the switching control circuit are separately provided, and it is monitored whether the main signal is using the working or protection transmission line, and the switching of the control system signal is performed. Follows signal switching. Normally, communication can be performed by selecting either the working or protection transmission line, but it is necessary not to use it when the transmission line is disconnected.

[0012]

A transmitting and receiving bus interface connected to a transmitting circuit and a receiving circuit, a working bus interface connected to a working transmitting transmission line interface and a receiving transmission line interface respectively on a transmitting side and a receiving side. A spare bus interface connected to the spare transmission line interface and the reception line interface, and a bidirectional bus network for connecting the transmission / reception, working and spare bus interfaces are provided. A predetermined address is given to the interface. Each transmitting circuit adds a bus interface address designated by itself to a signal to be transmitted, and transmits the signal.

As described above, the transmission medium of the transmission circuit and the reception circuit on the transmission side and the reception side can be shared with the transmission line interface, and the circuit scale can be reduced.

[0014]

Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram of a line switching device according to an embodiment of the present invention.

In FIG. 1, a line switching apparatus includes transmission circuits 1 and 11 for transmitting signals to a transmission side and a reception side, respectively, and interfaces between the transmission circuits 1 and 11 and working and protection transmission lines. Working and protection transmission line interfaces 6A, 6B, 16A, 16B;
Receiving circuits 12 and 2 for receiving signals from the transmission circuits 1 and 11 of the other party, and working and protection transmissions respectively connected to the working and protection transmission line interfaces 6A, 6B, 16A and 16B of the other party. Working and protection receiving transmission line interface 1 as an interface with the channel
7A, 17B, 7A, and 7B.

The present invention is characterized in that the transmitting and receiving bus interfaces 3 and 13 connected to the transmitting circuits 1 and 11 and the receiving circuits 2 and 12 are respectively connected to the transmitting side and the receiving side. Credit transmission line interface 6
A, 16A and reception transmission line interface 7A, 1
Working bus interfaces 5A, 15 connected to 7A
A and spare transmission line interfaces 6B and 16B
And spare bus interfaces 5B and 15B connected to the transmission line interfaces 7B and 17B for reception and bus interfaces 3, 5A for transmission and reception, working and spare, respectively.
5B, 13, 15A, and 15B, and bidirectional bus networks 4 and 14 for connecting the active and standby bus interfaces 5A, 5B, 15A, and 15B each having a predetermined address. Is to include means for adding the address of the bus interface 5A, 5B, 15A, 15B specified by the own side to the signal to be transmitted.

The above signal is a control system signal which is transmitted while being superimposed on the transmission path for the main signal.

The operation of the line switching device having such a configuration will be described.

In FIG. 1, a bus interface 5A,
5B is given a predetermined address, and the transmission circuit 1 adds the address of the bus interface specified to the generated signal and sends it out. The transmitted signal is the bus interface 3
-Bidirectional bus network 4-bus interface 5A of specified address (when address of bus interface 5A is specified)-transmission line interface 6A-transmission line-reception transmission line interface 17A-bus interface 15A-both The signal is input to the receiving circuit 12 via the directional bus network 14-bus interface 13. The same applies when the address of the bus interface 5B is specified.

The same applies to signal transmission in the reverse direction.

FIG. 2 is a block diagram of an optical transmission device to which the line switching device of the present invention is applied. FIG. 3 shows a frame format of the synchronous transport signal level -1 of the line switching apparatus of the present invention. FIG. 4 is a diagram showing the bit position numbers of the synchronous transport signal level -1 frame of the line switching apparatus of the present invention.
FIG. 5 is a diagram showing the details of the transport overhead of the frame of the synchronous transport signal level -1 of the line switching apparatus of the present invention.

As described above, in this embodiment, the transmission circuit and the reception circuit can share the bidirectional bus network, so that it is not necessary to have a transmission unit and a reception unit independently, and the line switching device can be simplified and reduced in size. .

[0023]

As described above, according to the present invention, the transmission medium on the transmission side and the reception side and the connection medium between the reception circuit and the transmission line interface can be shared, and the circuit scale can be reduced. There is.

[Brief description of the drawings]

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

FIG. 2 is a block diagram of an optical transmission device to which the line switching device of the present invention is applied.

FIG. 3 is a diagram illustrating a frame format of a synchronous transport signal level -1 of the line switching apparatus of the present invention.

FIG. 4 is a diagram showing bit position numbers of frames of synchronous transport signal level -1 of the line switching apparatus of the present invention.

FIG. 5 is a diagram showing the details of the transport overhead of the frame of the synchronous transport signal level -1 of the line switching apparatus of the present invention.

FIG. 6 is a block diagram of a conventional line switching device.

[Explanation of symbols]

1, 11 Transmission circuit 2, 12 Receiving circuit 3, 5A, 5B, 13, 15A, 15B Bus interface 4, 14 Bidirectional bus network 6A, 16A Active transmission line interface 6B, 16B Spare transmission line Interfaces 7A, 17A Active receiving transmission line interface 7B, 17B Spare receiving transmission line interface 21, 31 Branch circuit 22, 32 Switching control circuit 23, 33 Selection circuit 21A, 21B, 31A, 31B Transmission line state monitoring circuit

Claims (2)

(57) [Claims] 1. A transmission circuit for transmitting a signal to a destination on a transmission side and a reception side, respectively, a working and protection transmission transmission line interface as an interface between the transmission circuit and a working and protection transmission line, A receiving circuit for receiving a signal from the preceding transmitting circuit, and a working and protection receiving transmission line interface as an interface between the working and protection transmission line interfaces respectively connected to the other working and protection transmission transmission line interfaces In the line switching device comprising: a transmission / reception bus interface connected to the transmission circuit and the reception circuit on the transmission side and the reception side, and an active transmission line interface and a reception line interface, respectively. The connected working bus interface and the spare transmission line interface A spare bus interface connected to the transmission and reception transmission line interface, and a bidirectional bus network for connecting the transmission / reception, working and protection bus interfaces, wherein each of the working and protection bus interfaces is a predetermined bus interface. A line switching device having an address, wherein each of the transmission circuits includes means for adding an address of a bus interface designated by the transmission circuit to a signal to be transmitted. 2. The line switching device according to claim 1, wherein the signal is a control system signal transmitted by being superimposed on a transmission path for a main signal.