JPH0697902A - Communication circuit alternate system - Google Patents

Abstract

PURPOSE:To execute a detour of a circuit with respect to a network service having a demultiplexing function by detecting abnormality at every route of data and a executing selection of existing and stand-by circuits. CONSTITUTION:A TDM equipment TO is connected to TDM equipments T1-T3 through existing and stand-by circuits of a network N having a demultiplexing function. In such a state, a demultiplexing part J multiplexes and outputs received data from terminals A1-G1, and also, separates multiple received data and sends it to a control information adding/detecting part K. The control information adding/detecting part K adds abnormality detection information at every data route, and sends it to a selector part L for selecting the existing circuit and the stand-by circuit. In such a way, when abnormality is detected, the selector part L is operated only with regard to a data route in which abnormality is detected and communication data is allowed to make a detour to the stand-by circuit.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a communication line detour system for automatically switching from an abnormal line to a normal line when a line failure occurs.

[0002]

2. Description of the Related Art A conventional TDM (Time D) as shown in FIG.
In the communication method using the devices T1 and T2, the data A is transmitted between the terminals A1 and A2, and the terminal B1
Data B between B2, data C between terminals C1 and C2,
When performing communication, if the working line N1 is normal, the multiplexing / separating unit W multiplexes the data A, B, and C, and transmits / receives by the working line N1 via the selector unit L and the line interface IF1.

When the line interface IF1 detects an abnormal state of the working line, that is, out-of-sync of the frame, it notifies the selector unit L of the abnormality by the switching signal S1, and the selector unit L switches the line, thereby changing the interface. Data is transmitted and received by the protection line N2 via the IF2.

Therefore, as shown in the time chart of FIG. 6, when the frame has the line frame bit F and the time slots TS1 to TS5, the data A and the slots TS1 to TS3 of each frame on the working line N1 are respectively stored. B and C are inserted, but when the switching signal S1 is input to the selector L, data A,
B and C are slots TS1 of each frame on the protection line N2
~ Inserted in TS3 and transmitted / received, normal data is obtained as multiplexed data.

[0005]

By the way, 1: 1 T
The above-mentioned line detour system is known for connection between DM devices, but the line detour system is not yet known for connection between 1: n TDM devices.

Therefore, according to the prior art, when data is multiplexed / demultiplexed in a network (for example, an NTT network), it is not possible to detect an abnormality in each route of data at the time of network service. There is a problem that the bypass function of the network service cannot be used because the protection line cannot be selected.

The present invention has been made in consideration of such a situation, and by detecting an abnormality in each data route and selecting a working / protection line for each data route, a multiplexing / demultiplexing function is realized. It is intended to provide a communication line detouring method that enables a circuit service to be detoured.

[0008]

FIG. 1 is a block diagram showing the principle of the present invention. The present invention, as shown in FIG. 1, includes one TDM device T0 and a plurality of TDM devices T1 and T1.
A network N having a function of multiplexing and demultiplexing 2 and T3.
And the TDM device multiplexes and outputs the transmission data from a plurality of terminals, separates the multiplexed reception data and distributes to each of the terminals, and a working line of the network N. Selector section L for selecting the backup line
And the abnormality detection information added to the transmission data output from the multiplexer / demultiplexer J for each data route and transmitted to the selected line, and the abnormality detection information added to the reception data from the line is detected. Equipped with control information addition / detection unit K,
The present invention provides a communication line detouring method characterized in that the selector unit L is operated only for a data route in which the control information addition / detection unit K has detected an abnormality to divert communication data to the protection line.

[0009]

2 is a time chart showing the operation of the present invention. Data A between terminals A1 and A2, data B between terminals B1 and B2, data C between terminals C1 and C2, data D between terminals D1 and D2, and terminals E1 and E2 shown in FIG.
Communication between the terminals F1 and F2 with data F, and between the terminals G1 and G2 with data G, and the TDM devices T0-T1, T0-T2, and T0.
Assuming that the abnormality detection information corresponding to each data route between −T3 is abc, de, and fg, respectively, the frame of communication data on the working line includes the line frame bit F as shown in FIG. Time slots TS1 to TS
Data A to C in 3 and information abc in time slot TS4
However, the data D and E in the time slots TS5 and TS6,
Information de is written in the time slot TS7 and the time slot TS
8 and TS9, data F and G, time slot TS10
Information fg is inserted in.

On the other hand, the time slots TS1 to TS10 of the communication data frame on the protection line are set to the "none" state in which no data is inserted. When an abnormality occurs in the route TDM device (data route between T0 and T1) of the data A, B, and C during communication using the working line, the control information addition / detection unit K notifies the information abc. Based on the above, the selector signal L is output, and the selector unit L diverts only the routes of the generated data A, B, and C to the protection line.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the embodiments shown in the drawings. This does not limit the invention. FIG. 3 is a block diagram showing an embodiment of the present invention, and FIG. 4 is a time chart showing the operation of the embodiment. In FIG. 3, T0 is a TDM (Time Division Multiplexer) device, N is a network having a multiplexing / separating function (for example, an NTT network), T1 to T3 are TDM devices connected to the TDM device T0 via the network N, and A1. -G1 are terminals connected to the TDM device T0, A2-C2 are TDM
The terminals D2 to E2 connected to the device T1 are TDM devices T
2, terminals F2 to G2 are terminals connected to the TDM device T3. Each of the TDM devices T0 to T3 includes a terminal interface 1, a multiplexing / demultiplexing unit 2, a control information adding / detecting unit 3, and line interfaces 4 and 5.

The TDM device T0 is an active network (for example, an NTT network) having a multiplexing / separating function.
It is connected to the TDM devices T1 to T3 via a protection line.

The terminal interface unit 1 includes terminals A1 to G
The data format of 1 is converted into the TDM bus format inside the TDM device. The multiplexing / separating unit 2 performs a function of multiplexing the terminal data D from the terminal interface unit 1 and transmitting it to the control information adding / detecting unit 3 in the TDM bus format, and an inverse conversion function thereof.

The control information addition / detection unit 3 adds additional information for each data route, that is, for each of the three data routes between the TDM devices T0 and T1, between the TDM devices T0 and T2, and between the TDM devices T0 and T3. When an abnormality is detected, the TDM bus time slot is switched to the working / protection line side.

The line interface units 4 and 5 are T inside the apparatus.
Converts between DM bus format and line format.

In such a configuration, the terminals A1-A2
Data A between terminals, data B between terminals B1 and B2, data C between terminals C1 and C2, data D between terminals D1 and D2, data E between terminals E1 and E2, terminals F1 and F2.
Communication between the terminals G1 and G2 is performed with data G, and between the terminals G1 and G2 is performed with data G.
The abnormality detection information corresponding to the data route between 0-T2 and T0-T3 is abc, de, and fg, respectively.

As shown in FIG. 4, in a normal state, the frame of communication data on the working line is provided with the line frame bit F, the time slots TS1 to TS3 contain the data A to C, and the time slot TS4 contains the information abc. , Data D and E in time slots TS5 and TS6, information de in time slot TS7, and time slots TS8 and TS9.
Data F and G, and information fg is inserted in the time slot TS10. On the other hand, in the time slot of the frame on the protection line, no data is inserted, that is, the state is “none”.

Then, using the working line, the TDM device T
0 and the TDM devices T1, T2, T3 are communicating with each other, a data route between the TDM device T0 and the TDM device T1, that is, a route of the data A, B, C indicates an abnormality.
When detected by abc, only the data A, B, and C are inserted into the time slots TS1 to TS3 of the protection line, that is, the data A, B, and C, as shown in "abnormal time" in FIG.
C is diverted to the protection line.

At this time, the T inside the TDM devices T0 to T3 is
FIG. 4 shows TMD bus data on the DM bus. That is, in the terminal data D0 transmitted and received between the terminal interface 1 and the demultiplexing unit 2, the data A to G are No. 0 to
No. In the multiplexed data D1 which are inserted in the time slots of No. 6 in any order and are exchanged between the demultiplexing unit 2 and the control information adding / detecting unit 3, the data A to G are No. 8 to No. 14
Are inserted in a predetermined order in the time slot of.

Then, in the multiplexed data D2 transmitted and received between the control information addition / detection unit 3 and the working line and the protection line of the network N, the information abc and the data A, B and C are No. under normal conditions. 16-No. In the time slot of 19, the information de and the data D and E are No. 20-No. Two
The information fg and the data F and G are respectively inserted in the two time slots. That is, normally, all of these data are inserted into the time slot for the working line.

On the other hand, when there is an abnormality, for example, when the control information addition / detection unit 3 detects an abnormality in the information abc, as shown in FIG. 4, the information abc and the data A,
B and C will be inserted in the time slot for the protection line.

In this way, the line used can be switched in units of data routes by detecting the additional information added to each data route, so that 1: N TDM devices are connected via a network having a multiplexing / separating function. Even now,
Mutual detour operation of the protection line is effectively performed.

[0023]

According to the present invention, by detecting a failure for each data route in a network having a multiplexing / demultiplexing function, for example, an NTT network, it is possible to make a detour for each data route.

[Brief description of drawings]

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

FIG. 2 is a time chart showing the operation of FIG.

FIG. 3 is a block diagram showing an embodiment of the present invention.

FIG. 4 is a time chart showing the operation of the embodiment.

FIG. 5 is a block diagram showing a conventional example.

FIG. 6 is a time chart showing an operation of a conventional example.

[Explanation of symbols]

 T0 TDM device T1 TDM device T2 TDM device T3 TDM device 1 Terminal interface 2 Multiplexing / separating unit 3 Control information adding / detecting unit 4 Line interface 5 Line interface N network A1 to G1 terminals A2 to G2 terminals

Claims (1)

[Claims] 1. A TDM device (T0) and a plurality of TDs
M devices (T1, T2, T3) are connected via a network (N) having a multiplexing / separating function, and each TDM device multiplexes and outputs the transmission data from a plurality of terminals, and multiplex reception data. From the multiplexer / demultiplexer (J), a selector (L) that selects a working line and a protection line of the network (N), and a multiplexer / demultiplexer (J) that separates and distributes the data to each terminal. Equipped with a control information addition / detection unit (K) for adding the abnormality detection information to the transmission data for each data route and transmitting it to the selected line and detecting the abnormality detection information added to the reception data from the line A communication line detouring method characterized in that the selector unit (L) is operated only for a data route in which the control information addition / detection unit (K) has detected an abnormality to detour communication data to the protection line.