JPH0316437A - Line switching system - Google Patents

Abstract

PURPOSE:To use any line as an active/standby line as well by connecting 2nd, 3rd transmission/reception terminals in a loop between plural line switching sections, connection a 1st transmission/reception terminal of an optional line switching section to an upperstream line as an active system and using remaining switching section as a standby system. CONSTITUTION:A line switching section SW is provided with a 1st transmission/ reception terminal SIN/ROUT connected to an upperstream line Ca, a 2nd transmission reception terminal SINP/ROUTP connected to the upperstream line from other line switching section, a 3rd transmission reception terminal SIN/ ROUT transmission/reception terminals SOUTP/RINP connected to an upperstream line to other line switching section, and a 4th transmission/reception terminal SOUT/RIN connected to downstream line 1.... The SIN and the SOUT and the RIN and ROUT are connected in the line switching section SW1 and also in the SW2 similarly, as well and two active systems of Ca-SW1-LTU1-C1 and Cb-SW2-LTU2-C2 are in operation. When the upperstream line Ca is connected to the SW3, the C2, C3 are active systems and the C1 is a standby system and when the Cb is connected to the SW3, the C1 and C2 are used as active systems and the C2 is the standby system.

Description

[Detailed Description of the Invention] [Summary of the Invention] Regarding a line switching method for a transmission system having a working line and a protection line, the object of the present invention is to enable any line to be used as a working line or a protection line. In a line switching system for a transmission system having a line interface unit and a line, the line switching unit includes a first transmitting/receiving terminal connected to an upstream line, and a first transmitting/receiving terminal connected to an upstream line from another line switching unit. a second transmitting/receiving terminal connecting the upstream line to another line switching section, a third transmitting/receiving terminal connecting the upstream line to another line switching section, and a fourth transmitting/receiving terminal connecting the downstream line; A switch is provided to change connections between the lines, and the second and third transmission/reception terminals of the plurality of line switching units are connected in a loop, and the first transmission/reception terminal of any one of the plurality of line switching units is connected to the second and third transmission/reception terminals of the plurality of line switching units. The line interface unit that connects to the upstream line and the downstream line are the working lines,
The remaining line switching unit, the line interface unit connected thereto, and the downstream line are used as a protection line, and when a failure occurs in the working line, the line is switched to the protection line by switching the switch.

(Industrial Application Field) The present invention relates to a line switching method for a transmission system having a working line and a protection line.

In recent years, the demand for data transmission in communication systems has increased rapidly, and it has become common to provide backup lines to prevent data loss due to failures such as cable breaks and line deterioration. It is required that this protection line can be constructed flexibly to accommodate changes or expansions.

[Conventional technology]

Figure 5 shows the conventional method. SW (subscripts .2, . . . are omitted as appropriate; the same applies hereinafter) is a line switching unit, LTU is a line interface (line terminal unit), and C is a line. Line switching unit SW1 connected to the upstream line (equipment side transmission line or previous stage transmission line) C-, Cb
, SW2, line interface LTUL, LTU2, downstream side (hereinafter referred to as upstream side) line C1
, C2 constitute a working line, and a line switching unit SW3, a line interface LTU3, and a downstream line NfAC3 constitute a protection line.

The line switching section SW3 of the protection line is connected to the line switching sections SW1 and SW2 of the working line, so that it can be replaced in the event of a failure of the working line. That is, Fig. 5 (
In a), during normal operation, SW1 and SW2 are connected as shown by dotted lines, the working line is in operation, and the protection line is inactive. If the working line 1 becomes faulty, the situation will be as shown in FIG. 5(b), where the working line 2 and the protection line will be in operation, and the working line I will be inactive. If the working line 2 becomes faulty, the situation will be as shown in FIG. 5(C), and the working line 2 will be suspended while the working line 1 and the protection line are in operation.

Note that there are LTUs and SWs on the other side of the lines C1 to C3 (only the LTUs are shown by dotted lines), and similar line switching is performed.

[Problems to be Solved by the Invention] In the conventional system, the working line and the protection line are fixed, and a failure of the working line 1 or 2 is simply replaced by the protection line. This means that lines may be moved due to future increases in communication demand.
There is no freedom to change lines such as expansion, and system construction lacks flexibility.

The object of the present invention is to improve this problem and to enable any line to be used as a working/protection line.

[Means to solve the problem]

As shown in FIG. 1, in the present invention, the line switching unit SW has a first transmitting/receiving terminal SI connected to the upstream line C3.
N/ROUT, a second transmitting/receiving terminal srNP/ROυTP connected to the upstream line from another line switching unit
, a third sending/receiving terminal SOUTP/R INP that connects the upstream line to another line switching section, and a fourth sending/receiving terminal SOIJT/RIN that connects the downstream line C1, . . . will be established. Further, although not shown, a switch is provided to change the connection between these terminals.

Between the plurality of line switching units SWI to SWS, the second and third
Connect the transmit/receive terminals of the terminal in a loop.

In this example, any one of these line switching units is S.
First transmitting/receiving terminal SIN/ROtl of WI and SW2
T is connected to the upstream lines C- and Cb, making these the working system, and the remaining line switching sections serve as the backup system.

The control unit CONT has a processor, etc., and upon receiving failure information from the LTU, switches the line switching unit accordingly to perform line switching. Note that T indicates transmission and R indicates reception. LTU at the other end of lines C1 to C3,
Providing the SW is the same as in FIG. 4. Also SINP
P such as "P" indicates protection (pre-1).

[Operation] In this system, under normal conditions, SIN and SOUT, and RIN and ROUT are connected in line switching unit SWl, and the same is true for SW2, so that C, -SWI-LTUI-C
1. Two current systems of Cb-SW2-LTU2-C2 are in operation.

When the working line C1 becomes faulty, the line switching unit SW performs the switching shown by the dotted line in FIG. -SWI~
SW3-LTU3-C3, C, SW2-LTU2-C2
The working line C2 and protection line C3 are in operation, and the working line C1 is inactive.

In FIG. 2, the connections between the line switching units are summarized into two, the transmitting side and the receiving side.

The same applies if the working line C2 becomes a failure, and the C1-SW
I-LTUI-C1, Cb-sw2-sw3-LTU
Working line c1 and protection line C3 are in operation on route 3-C3.
The working line c2 is suspended.

Also, if you connect the upstream line C1 to SW3, 02 and C3 become active, and Ct becomes a backup, and if you connect C to SW3, C
I and 03 are currently used, and c2 is used as a backup line, and similar failed lines are substituted by the backup line.

In this way, the present invention can use any of the plurality of lines for active use and use the rest as backup, improving the flexibility of the system. Also, line switching parts sw1, SW2, SW3
The connection between them can be made by loop wiring, not radial wiring from the standby side to the working side.

〔Example] FIG. 3 shows an embodiment of the line switching unit SW.

Rim and R Ib, RZa and Rib, R3a and R :l
bs R <a and R ah are relay changeover switches, and HYB is a hybrid circuit. When each switch is in the state shown in the figure, it is normal, and SIN-HYB-
SOUT. ．． The upstream/downstream lines are connected via the R IN-ROOT route, and the active system is in operation. At this time, the second
, the third transmitting/receiving terminal is folded back (short-circuited). That is, SINP-SOUTP, RINP-ROU
The TP route has been completed.

When the working line C1 becomes a failure, the switch of the line switching section is switched as shown in FIG. Now C. is C3
It will be connected to Although the line switching unit SW2 is omitted in this figure, SW2 assumes the normal position.
It is in a through state.

Even if line 1 is disconnected from SW1 due to a failure, hybrid circuit HYB continues to transmit to line C1. This is for failure recovery. In other words, if you do this, the downstream side will be able to receive the transmitted signal immediately upon recovery from a fault (for example, a break in the transmission line) (this will not happen if you do not send it), so you can know when the fault recovery is complete. You can start the system restart process.

Switch R. and R lb+ R2a and R Zb+
R3. , R3b, R41, and R4b are interlocking switches, which are on the a side when normal, as shown in FIG. 3, and are on the b side when switched. When the own system is the active system and is to be suspended, and when the own system is the standby system and it is replaced, SW1 and SW3 in Figure 4 are used.
As shown, R2 and R3, R, and R4 are switched.

〔Effect of the invention〕

As explained above, according to the present invention, a protection line can be constructed anywhere on the system, which greatly contributes to flexibility in line design. Furthermore, connections between line switching units are easy, and there is no possibility of wiring congestion.

[Brief explanation of the drawing]

Fig. 1 is a diagram of the principle of the present invention, Fig. 2 is an explanatory diagram of line switching operation, Fig. 3 is a circuit diagram showing an embodiment of the line switching section, and Fig. 4 is a circuit diagram showing the switch position during line switching. , FIG. 5 is an explanatory diagram of a conventional example. In FIG. 1, SW is a line switching unit, LTU is a line interface unit, and Cl-C3 is a line. Applicant 乍r Shitsu StockΔ Sχ Company

Claims (1)

[Claims] 1. Multiple line switching units (SW1, SW2,...)
, line interface section (LUT_1, LUT_2, ・
...), and lines (C1, C2,...), in which the line switching section has a first transmission/reception terminal (SIN, ROUT) connected to the upstream line. , a second transmission/reception terminal (S
INP, ROUTP), the third transmit/receive terminal (SOUTP, RIN) that connects the upstream line to other line switching units
A fourth transmitting/receiving terminal (SOUT, RIN) is provided to connect to P) and the downstream line (C_1,...), and a switch is also provided to change the connection between these terminals, allowing multiple line switching. a line interface unit that connects the second and third transmitting/receiving terminals of the unit in a loop, and connects the first transmitting/receiving terminal of any one of the plurality of line switching units to the upstream line; The downstream line is used as a working line, the remaining line switching unit, the line interface unit connected thereto, and the downstream line are used as a protection line, and in the event of a fault in the working line, the line is switched to the protection line by switching the switch. line switching method.