JPH0575579A - Line switching system - Google Patents

Abstract

PURPOSE:To reduce the propagation delay difference between a current line and a standby line. CONSTITUTION:n current lines ((n) is an interger equal to or larger than 2) are divided to current lines 101 to 10i and current lines 201 to 20j (i+j=n), and selecting circuits 11 to 1i and selecting circuits 21 to 2j are arranged correspondingly to respective divided current lines. A selecting circuit 31 is arranged for a standby line 301. Selecting circuits 11 to 1i and the selecting circuit 31 are connected by longitudinal connection lines 111 to 11i, and selecting circuits 21 to 2j and the selecting circuit 31 are connected by longitudinal connection lines 221 to 22j. If fault occurs in a current line, the pertinent selecting circuit selects the data signal sent to the current line and sends the signal to the selecting circuit 31 of the standby line through longitudinal connection lines 111 to 11i or longitudinal connection lines 221 to 22j.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a line switching system, and particularly in a system having n (n is an integer of 2 or more) working lines and one protection line, when a failure occurs in the working line, The present invention relates to a line switching system for transmitting a data signal of a working line in which a failure has occurred to a protection line.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG. 2, n (n is 2
The above-mentioned integers) working lines 301 to 30n and one protection line 401 are provided with selection circuits 31 to 3n and a selection circuit 41, and each selection circuit is connected to the vertical connection line 3
31 to 33n are connected to each other.

Here, the selection circuits 31 to 3n receive the data signals D1 to Dn, respectively, and the working lines 301 to 30n.
When a failure occurs in the working line that sends the data signal to the vertical connection line 331.
To 33n.

Now, for example, when a failure occurs in the working line 302, the selection circuit 32 sends the data signal D2 to the vertical connection line 332, as shown in FIG. The data signal transmitted to the vertical connection line 332 is input to the selection circuit 41 of the protection line via the selection circuit 31 and the vertical connection line 331, and is further transmitted to the protection line 401 via the selection circuit 41.

In this way, when a failure occurs in the k (1≤k≤n) th working line 30k, the data signal Dk is
It is sent to the protection line selection circuit through the k selection circuits.

Although the switching on the transmitting side has been described above, the same applies to the receiving side.

[0007]

In the above-mentioned conventional line switching system, a delay occurs in proportion to the number of selection circuits through which the data signal to be switched passes, and the same delay occurs on the receiving side. Therefore, there is a problem that the difference in propagation delay between the working line and the protection line increases, and the scale of the compensation circuit for compensating for the difference in propagation delay increases.

It is an object of the present invention to provide a line switching system capable of reducing the propagation delay difference between the working line and the protection line and reducing the scale of the propagation delay difference compensating circuit.

[0009]

According to the line switching system of the present invention, n selections are made for selecting a data signal which is respectively provided to n (n is an integer of 2 or more) working lines and is being transmitted when a failure occurs. A circuit and a protection line selection circuit for transmitting the data signal selected by the n selection circuits to one protection line, and through a vertical connection line provided by vertically cutting the n selection circuits. In a line switching system for transmitting the selected data signal to the protection line selection circuit,
The n selection circuits are divided into N (N is an integer of 2 ≦ N ≦ n) groups, and the selected data signal is selected via the vertical connection line provided for each group as the protection line selection. Configured to deliver to a circuit.

[0010]

The present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of the present invention, one for n (n is an integer of 2 or more) working lines.
The transmission side is shown having a protection line of a book for switching. Here, the n working lines are replaced by working lines 101 to 10
i and working lines 201 to 20j (where i and j are i +
j is a positive integer that satisfies n = n.

By the way, the selection circuits 11 to 1i are arranged on the working lines 101 to 10i, respectively, and the working lines 201 to 10i are arranged.
Selection circuits 21 to 2j are respectively arranged in
A selection circuit 31 is arranged on the protection line 301. Further, the selection circuits 11 to 1i include the vertical connection lines 111 to 111.
11i is connected to the selection circuit 31. Similarly, the selection circuits 21 to 2j are connected to the selection circuit 31 via the vertical connection lines 221 to 22j.

The selection circuits 11 to 1i have a data signal D11.
D1i to D1i are received and sent to the working lines 101 to 10i, and when a failure occurs in the working line, data signals are sent to the vertical connection lines 111 to 11i. Similarly,
The selection circuits 21 to 2j respectively receive the data signals D21 to D2j and send them to the working lines 201 to 20j, and when the working line has a failure, send the data signals to the vertical connection lines 221 to 22j.

Now, for example, when a failure occurs in the working line 201, the selection circuit 21 sends out the data signal D21 to the vertical connection line 221 as shown in FIG. The data signal sent to the vertical connection line 221 is sequentially sent to the next selection circuit via the selection circuit 22 and the vertical connection line 222, and then to the protection line selection circuit 31 via the selection circuit 2j and the vertical connection line 22j. Sent out. In this case, the data signal has passed through the j selection circuits before being transmitted to the selection circuit 31.

In this way, when a failure occurs in the working lines 201 to 20j, the data signal can be sent to the selection circuit of the protection line through the maximum j selection circuits. Similarly, when a failure occurs in the working lines 101 to 10i, the data signal can be sent to the selection circuit of the protection line after passing through a maximum of i selection circuits. Therefore, for example, when an even number of working lines is divided into two by the same number, i = j = n / 2,
The maximum delay amount can be reduced to 1/2 of the conventional maximum delay amount.

In the present embodiment, the case of two divisions has been described, but it is clear that the maximum delay amount can be further reduced by dividing into three or more.

[0017]

As described above, according to the present invention, n
(N is an integer greater than or equal to 2) The selection circuit provided in each of the working lines is divided into N (N is an integer of 2 ≦ N ≦ n) groups, and the selection circuit is provided in one protection line. By providing a vertical connection line for transmitting a data signal to each group, the maximum delay amount can be reduced to 1 / N as compared with the conventional case. Therefore, the propagation delay difference between the working line and the protection line can be greatly reduced, and the scale of the propagation delay difference compensating circuit can be reduced.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention.

FIG. 2 is a block diagram showing an example of a conventional line switching system.

[Explanation of symbols]

 11-1i, 21-2j selection circuit 101-10i, 201-20j Working line 111-11i, 221-22j Longitudinal connection line D11-D1i, D21-D2j Data signal 31 Backup line selection circuit 301 Backup line

Claims (1)

[Claims] 1. An n number of selection circuits which are provided on n (n is an integer of 2 or more) working lines and which select a data signal being sent out when a failure occurs, and are selected by the n number of selection circuits. A protection line selection circuit for transmitting the selected data signal to one protection line, and the selected data signal is supplied to the protection line selection circuit via a vertical connection line provided by vertically cutting the n selection circuits. In the line switching system for sending to, the n selection circuits are divided into N (N is an integer of 2 ≦ N ≦ n) groups, and the selection is performed through a vertical connecting line provided for each group. A line switching system, wherein the data signal is sent to the protection line selection circuit.