JP2797765B2 - Order wire signal transmission 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 an order wire signal transmission system used as a communication line in a communication network. In particular, the present invention relates to switching of order wire signal transmission when a transmission line failure occurs in a synchronous network ring system.

[0002]

2. Description of the Related Art In a ring system, two stations are connected by two transmission lines to form a ring, and signals in mutually opposite directions are transmitted to the two transmission lines. A protection method or the like is adopted in which the other is used as a spare transmission line, and in the event of a failure, a failure detection station returns a signal received from the working transmission line to the spare transmission line and transmits the signal in the reverse direction to rescue the main signal, and the like. In this case, the transmission line switching is performed by always performing communication within the ring using the transmission line switching control prefix. When a fault occurs, the stations at both ends of the fault point detect the fault and at the same time communicate with the opposite station using the prefix of the main signal to switch the transmission path.

[0003] Regarding the order wire signal, each station combines the order wire signal of the own station with the order wire signal from the upstream and transmits it downstream, and also combines the order wire signal of the own station with the order wire signal from the downstream and transmits it upstream. Further, in a ring system, in particular, since a transmission line is connected in a ring shape, an arbitrary station can be used so that a signal transmitted from the own station does not return to the own station after making a full round in the ring. Disconnect the east-west connection to eliminate the ring condition of the order wire signal.

[0004]

In this conventional order wire transmission system, when a transmission line failure occurs, the order wire signal is cut off by one station in the ring so as not to be in the ring state from the beginning, and at the point of failure, the order wire signal is cut off. , And the stations constituting the ring are divided into two for the order wire signal. For this reason, communication using order wires may not be possible.
In order to prevent this, at the time of a failure, it is necessary to connect the order wire signal at the one station that normally disconnected the order wire signal. Conventionally, this connection is manually performed and requires manual labor.If the station is not related to the failure, it is not noticed and the connection is not made and order wire communication between the separated stations is impossible. It may be.

An object of the present invention is to provide an apparatus for automatically detecting a failure when a failure occurs and appropriately taking appropriate countermeasures in such order wire communication.

[0006]

According to the present invention, a west line terminal, an east line terminal, an own station line terminal, the west line terminal and the east line terminal are connected and connected to the own station line terminal. An order wire connection circuit for branch connection of a line, a prefix termination circuit for terminating a prefix of a signal arriving at each of the west and east line terminals, and a signal to be transmitted from each of the west and east line terminals. A prefix insertion circuit for inserting a prefix, and a prefix appearing in an output of the prefix termination circuit, taking in a prefix to be sent to the prefix insertion circuit, and controlling the order wire connection circuit. Control means for monitoring the transmission path between all connected stations, and when a failure in the transmission path is detected in the monitoring means,
From the prefix code insertion circuit, the connection between the east and west of the other device which has been opened is closed, and the west line terminal and the east line terminal of a station having a transmission line including a failure point next to the own device are closed. And a control circuit for transmitting a control signal for releasing the connection on the side including the point of failure.

[0007] The monitoring means may be constituted by hardware different from the control circuit.

Further, a configuration may be employed in which three or more order wire signal transmission devices are connected in a loop by a transmission line.

[0009]

In the ring system, each connected station automatically monitors the state of the transmission line at all times, and when any station detects a failure, the station automatically generates a signal necessary for securing the transmission line of the entire system. Since the transmission is performed manually, the transmission path for the order wire signal can be promptly secured without manual operation.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIG. FIG. 1 is a configuration diagram of an embodiment of the present invention. In this embodiment, the west line terminal 1, the east line terminal 2, the own line terminal 3, the west line terminal and the east line terminal are connected, and the line connected to the own line terminal is branched. An order wire connection circuit 4, a prefix code terminating circuit 5 for terminating a prefix code of a signal arriving at each of the west and east line terminals, and a prefix code for a signal transmitted from each of the west and east line terminals. And a pre-code appearing in the output of the pre-code terminating circuit 5, and a pre-code to be sent is given to the pre-code inserting circuit 6, and the order wire connection circuit 4 And control means (drawing reference numerals 5 to 8).

Here, a feature of the present invention is that the control means is provided with a fault detecting circuit 8 as means for monitoring a transmission path between all connected stations, and the fault detecting circuit 8
When a failure in the transmission line is detected, the pre-code insertion circuit 6 closes the east-west connection of the other device which has been opened up to that point, and has a transmission line including a failure point next to the own device. And a control circuit 7 for transmitting a control signal for releasing the connection between the west line terminal and the east line terminal including the fault point.

The fault detecting circuit 8 is constituted by hardware different from the control circuit 7.

Further, an order wire signal transmission system can be configured by connecting three or more of the above order wire signal transmission devices in a loop by a transmission line.

Next, the operation of the embodiment of the present invention will be described with reference to FIGS.
This will be described with reference to FIG.

FIG. 2 and FIG. 3 are diagrams showing the configuration of a ring system in which four order wire signal transmission devices of the present invention are connected in a loop by a transmission line, and the flow of order wire signals or prefix codes for switching control at that time. It is.

As a specific means for detecting a failure in the transmission line, the failure detection circuit 8 monitors a received signal to detect signal input disconnection, frame synchronization loss, and deterioration of a code error rate.

As shown in FIG. 2A, each of the stations 21 to 24
Are assigned ID numbers, and each of the stations 21 to 24 recognizes the ID number of its own station and also recognizes the ID number of an adjacent station. The order wire signal cutting section 25 is provided to prevent a ring state of the order wire signal.

As shown in FIG. 2B, in the transmission line frame, a switching control prefix code for performing communication between stations and performing transmission line switching control when a failure occurs is secured.

The switching control prefix is a switching request command or a switching response command, and the I / O of the switching request or response source station.
D number, ID number of the switching request or response destination.

As shown in FIG. 3C, when a fault point 28 occurs on the outer circuit 26 between the station 23 and the station 24,
The fault detection circuit 8 of the line 26 outside the station 24 detects the fault. In response to this, the control circuit 7 of the station 24 performs switching control of the switching request including the switching request command, the own station ID number ID = 4, and the ID number 3 of the transmission source of the signal detecting the failure, ID = 3. The pre-code 29 is transmitted in the direction opposite to the fault point 28.

Each of the stations 21 to 24 analyzes the switching control prefix 29 in the received signal, detects the occurrence of a failure, and performs switching control.

The station 21 closes the connection between the east and west where the connection was opened when the transmission line was normal, and the station 22 is the next station, since the switching control prefix 29 of the switching request is not addressed to itself. Transfer to The receiving station 23 opens the side including the fault point 28 between east and west, which was closed when the transmission line was normal. At the same time, the station 23 responds to the switching request of the failure detecting station 24 by using a switching response command and its own station ID number ID = 3.
And the switching control prefix 30 of the switching response including ID = 4, which is the ID number of the transmission source of the switching request, in the direction opposite to the fault point 28.

The station 24 that has received the switching control prefix 30 of the switching response opens the side including the fault point 28 between the east and west, which was closed when the transmission path was normal, and opens the transmission path section including the fault point 28. Is the order wire signal cutting section 25, and the transmission path switching for failure handling is completed.

[0024]

As described above, in the ring system, the transmission line failure of the order wire signal is automatically detected and the line is automatically secured.
Order wire communication from the occurrence of a failure to the recovery can be quickly maintained without human intervention.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an apparatus according to an embodiment of the present invention.

FIG. 2 is a diagram illustrating a configuration of a ring system according to an embodiment of the present invention and a flow of an order wire signal or a switching control prefix.

FIG. 3 is a diagram illustrating a state when a failure occurs in the ring system according to the embodiment of the present invention.

[Explanation of symbols]

 Reference Signs List 1 West line terminal 2 East line terminal 3 Own station line terminal 4 Order wire connection circuit 5 Prefix termination circuit 6 Prefix insertion circuit 7 Control circuit 8 Fault detection circuit 21 Station ID = 1 22 Station ID = 2 23 Station ID = 3 24 station ID = 4 25 Order wire signal cut section 26 Outer loop line 27 Inner loop line 28 Failure point 29 Prefix code for switching control switching request 30 Prefix code for switching response switching control

Continuation of front page (56) References JP-A-4-291543 (JP, A) JP-A-4-284752 (JP, A) JP-A-4-23642 (JP, A) JP-A-3-173464 (JP) JP-A-2-198257 (JP, A) U.S. Pat. No. 4,640,955 (US, A) NEC Technical Report, VOL. 46 NO. 5, (No. 291) 1993, Togashi Tadahiko et al., "Embedded Optical Repeater", June 15, 1993 (58) Fields investigated (Int. Cl. ⁶ , DB name) H04L 12/42- 12/437 INSPEC (DIALOG) JICST File (JOIS) WPI (DIALOG)

Claims (2)

(57) [Claims] An order wire connection for connecting the west line terminal, the east line terminal, the own line terminal, the west line terminal and the east line terminal, and branch-connecting the line connected to the own line terminal. A circuit, a prefix termination circuit for terminating a prefix of a signal arriving at each of the west and east line terminals, and a prefix for inserting a prefix into a signal transmitted from each of the west and east line terminals. An order wire including a code insertion circuit, and control means for taking in a prefix appearing in an output of the prefix termination circuit, providing a prefix to be sent to the prefix insertion circuit, and controlling the order wire connection circuit. In the signal transmission device, the control unit monitors a transmission path between all connected stations, and the prefix code when a failure of the transmission path is detected in the monitoring unit. Close the east-west connection of the other device that has been opened up to then from the insertion circuit, and the side containing the point of failure of the west line terminal and the east line terminal of the station that has a transmission line containing a point of failure next to its own device look including a control circuit for sending a control signal to open the connection, said means for monitoring, another hardware from said control circuit
Order wire signal transmission apparatus characterized by being composed of A. 2. An order wire signal transmission device comprising three or more order wire signal transmission devices according to claim 1, which are loop-connected by a transmission line.