JPH07202861A - Standby line changeover control system - Google Patents

Abstract

PURPOSE:To obtain the standby line changeover control system in which lines are switched rapidly with simple configuration when a fault takes place in any active system transmission line in a transmitter comprising plural active system transmission lines and the standby line each comprising a transmission line and a reception line. CONSTITUTION:A branch line is provided to a transmission line 3 of each active system transmission line 1 to branch part of transmission data and identification data from an equipment identification data generator 16 are added to the branched data and the resulting data are sent to a transmission selector 8. The transmission data from each equipment are given to a transmission line of the standby system transmission line when a fault takes place in an equipment through a changeover control section 19 selecting the equipment and fault information is added to the transmission data and the resulting data are sent to an opposite station. On the other hand, reception data from the opposite station receive identification data in addition and the resulting data are sent to a standby system transmission line equipment. Identification data from an equipment identification data generator 16 and the identification data from the opposite station are collated and the reception line of the active system is switched into that of a standby system to the line finish changeover.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to digital communication, and more particularly to a backup line switching control system for switching a line to a backup system transmission line when a failure occurs in a certain transmission line among a plurality of active system transmission lines. .

[0002]

2. Description of the Related Art Generally, an active transmission system having a transmission line composed of a transmission line and a reception line is provided with a backup transmission line for a plurality of transmission systems. This is because when a failure occurs in a device or a transmission line of a certain active transmission system, the active transmission line in which the failure has occurred is immediately switched to the standby transmission line to avoid system interruption. In such a system including a plurality of active transmission lines including a backup transmission line, it is important to switch the line quickly and reliably when a failure occurs.

Now, let us consider a transmission system which is composed of one standby transmission system and N active transmission systems and has a transmission / reception bidirectional standby line switching function.

FIG. 3 is a block diagram of a conventional transmission system having the above configuration and function. Reference numeral 33 denotes a working transmission line, and 34 denotes a working reception line. There are a plurality of active transmission systems in one transmission system as a whole, and therefore, there are as many active transmission paths as the transmission lines 33 and the reception lines 34 as many as the active transmission systems. On the other hand, 35 is a backup transmission line, and 36 is a backup reception line. Here, a pair of backup transmission systems are provided for a plurality of active transmission systems. In the figure, thick lines indicate main signal lines, and thin lines indicate control signal lines, information monitoring lines, and the like.

Reference numeral 31 is a local station transmitting / receiving apparatus of the active transmission system, and 32 is a local station transmitting / receiving apparatus of the standby system transmission system. A part of the transmission signal transmitted to the active transmission line 33 is branched to the branch circuit 46 in the local station transmitter / receiver 31 and connected to the transmission direction selector 38. Reference numeral 38 is a transmission direction selector that selects the branch line 46 from each active transmission line 33 and connects it to the standby transmission line 35. Reference numeral 39 is a reception direction signal branch circuit for distributing the reception signal from the standby reception line 36 to the lead-in line 47 of each active transmission system. Reference numeral 37 is a reception direction selector for selectively connecting the service line 47 and the active reception line 34.

Reference numeral 44 denotes a switching control unit, which collects in-device monitoring information 45 including failure information (switching trigger) of each active transmission system, controls selection of a reception direction selector 37 and a transmission direction selector 38, and a transmission main unit. The switching control information is inserted into the signal overhead and the overhead switching control information of the received main signal is monitored.

[0007] When performing a 1: N backup switching control in a transmission system having such a backup transmission line, in order to transmit / receive to / from the opposite device, the presence / absence of the switching request, its degree, and switching A number for identifying the active transmission system issuing a request and connection information indicating which active transmission line in the transmission direction is connected to the standby transmission line are required. Here, for convenience of explanation, the information indicating the presence or absence and the degree of the switching request is “K1 (H)”, the active system number issuing the switching request is “K1 (L)”, and the connection information in the transmission direction is “K2”. ". 40 is "K1
(H) "and" K1 (L) "insertion circuit, 41 is" K2 "
, And the information to be inserted is transferred from the switching control unit 44. 42 is a monitor circuit for "K1 (H)" and "K1 (L)" sent from the opposite device, 43
Indicates a monitor circuit of "K2" sent from the opposite device. The information monitored here is the switching control unit 44.
Transferred to. Hereinafter, an example of a general bidirectional switching sequence will be described.

The switching control unit 44 constantly monitors the failure information of each active system. When a plurality of failures are detected, priority is given to the switching information to determine the switching request having the highest priority. The degree of this switching request and the system number issuing the switching request are "K1 (H)" and "K1 (L)", respectively.
Then, it is sent to the opposite device by 40. The opposite device detects this switching request, connects in the transmission direction, and returns the switching response as "K1 (H)", "K1 (L)" and the connection information as "K2". The switching control unit confirms this information at 42 and 43, and switches the selector 37 in the receiving direction. Further, the selector 38 is switched to establish connection in the transmission direction, and the information is inserted as 41 as “K2”. When this is detected by the opposite device, the selector in the receiving direction is switched to complete a series of bidirectional switching sequences. SDH (Synchronous D
digital Hierarchy) transmission device, K
The 2-byte overheads of 1 and K2 are assigned for switching control, and CCITT G. 783 defines the bit assignment and control sequence.

In the conventional backup switching control system described above, one switching control unit in the apparatus is
In addition to collecting the monitoring information of the transmission path and each part in the device, the switching information received from the opposite device is monitored to determine whether or not the switching can be executed, and all control information to be transmitted to the opposite device is generated. All selector control in is performed collectively. In a large-scale and complicated device, the range of collecting information is wide, and the selectors to be controlled are often distributed in many packages. Therefore, the collection of switching triggers (fault information) and its judgment and the control of the selector are controlled. In order to do so, a complicated control circuit for the entire device is required, and the device becomes expensive.

Further, since it takes a lot of time to collect and process the information and to control the selector, there is a problem that switching time is increased and quick line rescue becomes difficult.

According to the backup line switching control system of the present invention, at least one active transmission line having a transmission line and a reception line as a pair, and a transmission line and a reception line as a pair. At least one backup transmission line serving as a transmission line;
A branch line branched from the transmission line of each working transmission line, a switching control unit that receives and switches a monitoring signal from each device of each working transmission line, and the working transmission line designated by the switching control unit Among these, the transmission direction selector that connects the branch line of the working transmission line where the line has failed to the transmission line of the protection transmission line and the reception line of the protection transmission line A receiving direction signal branching circuit selectively connected to a service line connected to the equipment of the working system transmission line in which a failure has occurred in the path, and a switching selector for switching between the receiving line and the receiving line of the working system transmission line The switching selector is provided with a comparison circuit for transmitting a switching control signal.

In particular, in the above structure, each active transmission line is provided with an identification data generator for generating identification data for identifying the device of the partner station facing the own station from the other devices of the active transmission line, The identification data is sent to the comparison circuit and the first insertion circuit provided in the branch line, and the switching control unit, when a failure occurs in a device on the working transmission path, failure data indicating that the failure has occurred. To a second insertion circuit provided in the transmission line of the standby transmission line and a third insertion circuit provided in the reception line of the standby transmission line,
The first monitor circuit provided in the receiving line of the standby transmission line sends the switching data to the switching control unit to notify the switching of the active transmission line to the standby transmission line in the other station, and the switching data is sent to the switching control unit. The provided second monitor circuit sends the identification data from the partner station to the comparison circuit, and the third monitor circuit provided in the lead-in circuit sends the switching data to the comparison circuit to identify the identification data of the own station. The comparison circuit is switched from the receiving line of the active transmission line to the pull-in line when the identification data from the partner station match and the switching data indicates that the partner station has already switched. I am trying.

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

FIG. 1 is a block diagram showing an embodiment of a protection line switching control system of the present invention. In the figure, the basic configurations of the active transmission system and the standby transmission system are the same as those described in the conventional example (FIG. 3), and there are differences in the configurations of the switching control unit, the insertion circuit, the monitor circuit, and the like. The part to be described will be described.

Reference numeral 1 is a local station transmitting / receiving apparatus of the active transmission system, and 2 is a local station transmitting / receiving apparatus of the standby system transmission system.
Reference numerals 3 and 4 respectively denote a working transmission line and a reception line, which constitute a pair of working transmission lines. Numerals 5 and 6 are a spare transmission circuit and a reception line which form a pair of spare transmission lines.
Usually, the entire transmission system is composed of a plurality of active transmission systems and is equipped with one or more standby transmission systems.

Reference numeral 8 designates a backup transmission line 5 and a working transmission line 3
The selector 9 for selectively connecting the branch line 20 branched in the local station transmitter / receiver 1 from the above, or 9 uniformly distributes the received signal of the standby receiver to each active receiver line, or from the outside. It is a signal branch circuit for selecting one of the active transmission systems by a control signal and connecting it to the service line 21. A switching control unit 19 collects in-device monitoring information 18 including failure information (switch trigger) of each unit in the device,
Selector control, insertion of switching control information into the overhead of the transmission main signal, and monitoring of switching control information of the overhead of the reception main signal.

As described in the above-mentioned conventional example, when the 1: N preliminary switching control is executed, the control information that needs to be transmitted / received to / from the opposite device is the presence / absence of the switching request, its degree, and the switching. It is the number of the active system issuing the request and the connection information of the transmission line. Here again, for convenience of explanation, the information indicating the presence / absence and the degree of the switching request is “K1
(H) ”, the number of the active transmission path issuing the switching request is called“ K1 (L) ”, and the connection information in the transmission direction is called“ K2 ”. For example, as shown in FIG. 2, it is assumed that the frame is configured so that these pieces of information can be added to a part of the overhead portion in one frame of the transmission data.

Reference numeral 10 denotes an insertion circuit for "K1 (H)" and "K1 (L)", and the information to be inserted is transferred from the switching control unit 19. Reference numeral 17 represents an insertion circuit of "K2", and a fixed value is individually inserted by hardware setting in each active system. Reference numeral 12 is a monitor circuit of “K1 (H)” and “K1 (L)” sent from the opposite device, and the received information is transferred to the switching control unit 19.
Reference numeral 11 is a circuit for monitoring "K1 (L)" inserted at 10 and inserting it in an empty time slot of the reception signal of the standby system reception line 6, and this information is given by 9 to each working system drop line 21. And is monitored by 13 monitor circuits. Reference numeral 14 is a circuit for monitoring "K2" information transmitted from the opposite device. Reference numeral 15 denotes a control information comparison circuit, which transmits a device identification number generator 16 for generating identification data indicating a number for identifying the own station transmitting / receiving device of each active transmission system from other devices. There is "K
1 (L) ”and the received“ K2 ”match, the reception selector 7 controls and the signal from the backup transmission line is received. That is, it is confirmed that the active transmission system that has sent the in-device monitoring information 18 indicating that a failure has occurred to the switching control unit 19 is transmitting the switching request, and the opposite device responds to it to establish the connection. It has the function of confirming and immediately executing switching.

The receiving direction selector 15 can be easily realized by a simple combinational logic circuit. Note that 13, 14
Information monitored by each monitor circuit of the switching control unit 19
No need to transfer to.

An example of a general bidirectional switching sequence will be described below. The switching control unit 19 constantly monitors the failure information of each active transmission system. When a plurality of failures are detected, priority is given to the switching control section 19 to determine a switching request having the highest priority. The degree of this switching request and the system number issuing the switching request are "K1 (H)" and "K", respectively.
(L) ”is sent to the opposite device by 10. Here, “K1 (L)” is transferred to each active system by 11, and monitored at 14. The opposite device receives the switching request, connects in the transmission direction, and sends a switching response of "K1".
(H) ”,“ K1 (L) ”, and connection information is returned as“ K2 ”. “K2” is monitored at 13, and the reception direction selector 15 compares the three values with the monitor values of the hardware setting values 16 and 14, and when the three parties match, the reception direction selector 15 Is controlled so as to receive the reception signal of the standby system reception line 6. Further, the switching control unit 19 confirms “K1 (H)” and “K1 (L)” transmitted from the opposite device on the monitor circuit 12, switches the transmission direction selector 8, and connects in the transmission direction. . Since "K2" has been inserted by the insertion circuit 17 in advance, "K2" is transmitted at the same time when the transmission direction selector 8 is set. When this is detected by the opposite device, the reception direction selector 15 is switched, and a series of switching sequences to the standby system transmission line is completed.

In the above-described embodiment of the present invention, the number of backup transmission systems is one. However, when there are a large number of active transmission systems, or when it is desired to improve reliability even when there are few active transmission systems, a backup system is used. A plurality of active transmission systems may be provided. By providing multiple standby transmission systems,
Even if a failure occurs in two or more active transmission systems at the same time, it is possible to cope with the failure. In this case, it is sufficient to provide a control unit that allocates the standby transmission systems that are switched in the order in which failures occur.

As described above, in the backup line switching control system of the present invention, the control function of switching information with the opposite device, which is conventionally collectively performed by one switching control unit in the device, is distributed. ing. That is, the information about the connection in the transmission direction is set in the local station device of the active system transmission line and the local station device of the standby system transmission line, and the monitoring process is separated and combined with the selector control process in the reception direction for each active system. By operating each independently, the information input / output to / from the switching control unit is halved. This has the effect that the processing can be greatly simplified and, in turn, quick switching control can be performed.

In particular, if the backup line switching control system of the present invention is applied to a large-scale and complicated transmission system, the switching control configuration can be greatly simplified, and the device design and manufacturing cost can be reduced. be able to. Further, there is an effect that the processing in the switching control unit is simplified, the processing time is shortened, and quick line rescue is possible.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of a protection line switching control system of the present invention.

FIG. 2 is a diagram showing data for performing switching control in an embodiment of a protection line switching control system of the present invention.

FIG. 3 is a block diagram of a conventional protection line switching control system.

[Explanation of symbols]

 1 ・ ・ ・ Own station device of working system transmission line 2 ・ ・ ・ Own station device of protection system transmission line 3 ・ ・ ・ Standby system transmission line 4 ・ ・ ・ Standby system reception line 5 ・ ・ ・ Standby system transmission line 6 ・.. Backup system reception line 7 ... Reception direction selector 8 ... Transmission direction selector 9 ... Reception direction signal branch circuit 10 ... K1 (H), K1 (L) insertion circuit 11 ... K1 (L) Insertion circuit 12 ... K1 (H), K1 (L) monitor circuit 13 ... K2 monitor circuit 14 ... K1 (L) monitor circuit 15 ... Comparison circuit 16 ... Device identification number Generator 17 ・ ・ ・ K2 insertion circuit 18 ・ ・ ・ Monitoring information in device 19 ・ ・ ・ Switching control unit 20 ・ ・ ・ Branch line 21 ・ ・ ・ Service line 31 ・ ・ ・ Working system transmission line own station device 32 ・ ・・ Protection system transmission line own station device 33 ・ ・ ・ Working system transmission times 34 ... Working system receiving circuit 35 ... Standby system transmitting circuit 36 ... Standby system receiving circuit 37 ... Receiving direction selector 38 ... Sending direction selector 39 ... Receiving direction signal branching circuit 40 ...・ Insertion circuit 41 ・ ・ ・ Insertion circuit 42 ・ ・ ・ Monitor circuit 43 ・ ・ ・ Monitor circuit 44 ・ ・ ・ Switching control unit 45 ・ ・ ・ Monitoring information device inside 46 ・ ・ ・ Branch circuit 47 ・ ・ ・ Driving circuit

Claims (5)

[Claims] 1. At least one working transmission line having a transmission line and a reception line as a pair of transmission lines, and at least one transmission line and a reception line as a pair of transmission lines.
One standby transmission line, a branch line branched from the transmission line of each working transmission line, a switching control unit that receives and switches a monitoring signal from each device of each working transmission line, and the switching control The branch line of the working transmission line in which a failure has occurred in the working transmission line designated by the
A transmission direction selector for selectively connecting to the transmission line of the protection transmission line and a receiving line of the protection transmission line for a working transmission line in which a failure has occurred in each of the working transmission lines. A standby line switching control method comprising: a reception direction signal branch circuit connected to a drop line connected to the inside; and a switching selector that switches between the drop line and the reception line of the working transmission line. 2. Each of the active transmission lines includes an identification data generator that generates identification data for identifying a device of a partner station facing the own station from another device of the active transmission line, the identification data Is sent to a comparison circuit arranged between the identification data generator and the reception direction selector and a first insertion circuit provided in the branch line, and the switching control unit is configured to operate the active transmission path. When a failure occurs in the device, the failure data indicating the failure is received in the second insertion circuit provided in the transmission line of the standby transmission line and the reception of the standby transmission line. Each is sent to a third insertion circuit provided in the line, and by the first monitor circuit provided in the lead-in line,
The partner station identification data for identifying the working transmission line connected to the protection line in the partner station is sent to the comparison circuit, and the second monitor circuit provided in the lead-in circuit allows
The local system switching data that identifies the active system transmission line that is issuing the switching request in the local station is sent to the comparison circuit, and the active system transmission line that is identified by the identification data, the partner station identification data, and the local station switching data, respectively. Are matched,
2. The protection line switching control system according to claim 1, wherein the comparison circuit sends a switching signal to switch from the reception line of the working transmission line to the drop line. 3. A protection line switching control method, characterized in that a device having the same configuration as the local station device of the working transmission line according to claim 2 is opposed to each working transmission line. 4. The protection line switching control system according to claim 2, wherein a frame for adding the identification data and the switching data is provided in a transmission main signal. 5. A plurality of the backup transmission lines are provided, and when a failure occurs in the active transmission line, the unused backup transmission line is sequentially replaced with the failed active transmission line. The standby line switching control method according to claim 4, wherein switching is performed.