JPH06334566A - Switching method without short break - Google Patents

Abstract

PURPOSE:To provide the switching method without any short break which can reduces a one-sided facility load on a specific transmission equipment among transmission equipments constituting a network. CONSTITUTION:The respective signal repeating transmission equipments 3-10 are provided with variable delay circuits 11-18, control information is transmitted to the respective signal repeating transmission equipments 3-5 on a stand-by line side on the basis of the phase difference between an in-use line and the stand-by line which is measured by a reception-side terminal equipment 2 to set the delay quantities of respective variable delay circuits 11-13, and a system is switched according the phase matching between the in-use line and stand-by line.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a non-instantaneous switching method for a digital communication network.

[0002]

2. Description of the Related Art In a digital communication network composed of various transmission devices, a method shown in FIG. 2 has hitherto been taken as a non-instantaneous switching method for switching a working line to a protection line during communication. FIG. 2 is an explanatory diagram showing a conventional hitless switching method. In the figure, 51,5
2 is a terminal station device for transmitting and receiving a target signal, 53 to 60 are signal relay transmission devices for relaying transmission without terminating signals, and 65 and 66 are 0-system transmission lines and 1-system transmissions connecting terminal station devices 51 and 52. The 0-system transmission path 65 is composed of the signal transmission repeaters 56 to 60, and the 1-system transmission path 66 is composed of the signal transmission repeaters 53 to 55.

Further, the terminal device 52 has a phase difference measuring circuit 63 for measuring the phase difference of signals simultaneously sent from the terminal device 51 to the 0-system transmission line 65 and the 1-system transmission line 66, and has a memory inside. There are provided variable delay circuits 61 and 62 capable of variably setting the signal delay time by adjusting the timing of memory access, and a changeover switch 64 for selectively switching and outputting the outputs from the variable delay circuits 61 and 62.

Next, in such a digital communication network, a transmission line non-instantaneous switching operation from the working line to the protection line will be described. The state before switching is 0
It is assumed that the system transmission line 65 is the working line and the system 1 transmission line 66 is the protection line.

First, in the normal state, the target signal is transmitted from the terminal device 51 to the 0-system transmission line 65 and the 1-system transmission line 66.
Are simultaneously output to both terminals, and the respective signals are relayed via the signal relay transmission devices 53 to 55 or 56 to 60 constituting the transmission path and reach the terminal device 52. Here, the 0-system transmission line 65 and the 1-system transmission line 66 are
Since the line length and the number of signal relay / transmission devices that configure this are different, a phase difference occurs in the signals that reach the terminal station device 52 via both transmission paths.

The phase difference measuring circuit 63 of the terminal device 52 measures the phase difference between both signals by comparing the phases of the frames or multi-frames forming each signal, and the protection line, ie, 1 The variable delay circuit 61 on the system transmission line 66 side is controlled to match the phase on the working line side, that is, the 0-system transmission line 65 side. In response to the confirmation of the coincidence of the phases, the changeover switch 64 is operated to complete the non-instantaneous interruption switching process.

[0007]

Therefore, in the conventional hitless switching method as described above, the variable delay circuit is provided only in the terminal terminal device having the changeover switch, whereby the working line and the protection line are connected. Since the phase difference is adjusted, it is necessary to provide a large-capacity memory in advance in order to deal with the case where the path length difference between the working line and the protection line is large and the phase difference becomes large. There was a problem that equipment load increased. The present invention is intended to solve such a problem, and an object of the present invention is to provide a non-instantaneous interruption switching method capable of reducing a biased facility load on a specific device among transmission devices forming a network.

[0008]

In order to achieve such an object, a method of switching without interruption according to the present invention provides a signal relay transmission device for relaying a signal with an arbitrary signal delay amount according to control information. The terminal device on the receiving side measures the received signal phase difference between the working line and the protection line, and delays a predetermined delay to a predetermined signal relay transmission device according to the measurement result. The control signal that indicates the amount is sent to adjust the received signal phase difference, and when the phase of the received signal on the working line and the protection line match, the line is switched from the working line to the protection line. is there.

[0009]

Therefore, the control information corresponding to the received signal phase difference between the working line and the protection line is transmitted from the receiving side terminal device, and each signal relay transmission device delays the signal according to this control information. When the phase difference of the received signals in the receiving side terminal device is adjusted and the phases of the received signals of the working line and the protection line match, line switching is performed.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be described with reference to the drawings. FIG. 1 is an explanatory diagram showing a hitless switching method according to an embodiment of the present invention. In FIG. 1, reference numerals 1 and 2 are terminal devices that transmit and receive target signals. Further, 3 to 10 are signal relay transmission devices that relay and transmit signals without terminating signals, and 11 to 18 are variable delay circuits provided in the respective signal relay transmission devices 3 to 10. The scale, that is, the memory capacity is determined according to the network configuration and the hardware configuration of each transmission device.

Reference numerals 21 and 22 are 0 connecting the terminal devices 1 and 2.
The 0-system transmission line 21 is composed of the signal transmission relay devices 3 to 5, and the 1-system transmission line 22 is composed of the signal transmission relay devices 6 to 10.

Further, the receiving side terminal device 2 has a phase difference measuring circuit 1 for measuring the phase difference between the signals transmitted from the transmitting side terminal device 1 to the 0-system transmission line 21 and the 1-system transmission line 22 at the same time.
A changeover switch 20 for selectively switching and outputting the output from the 9th and 0th system transmission lines 21 and the 1st system transmission line 22 is provided.

Next, as the operation of the present invention, the operation of switching the transmission line without interruption to the protection line in this digital communication network will be described with reference to FIG. In the state before switching, it is assumed that the 0-system transmission line 21 is the working line and the 1-system transmission line 22 is the protection line.

First, in the normal state, the transmitting side terminal device 1
The target signals are 0-system transmission line 21 and 1-system transmission line 2
It is output to both of 2 at the same time, and each signal is
Signal relay transmission devices 3 to 5 or 6 constituting the transmission line
It is relayed via 10 and reaches the receiving side terminal device 2. Here, the 0-system transmission line 21 and the 1-system transmission line 22 are
Since the transmission path length and the number of signal relay transmission devices that constitute this are different, there is a phase difference in the signals that reach the reception-side terminal station device 2 via both transmission lines.

The phase difference measuring circuit 19 of the receiving side terminal device 2
Measures the phase difference between both signals by comparing the phases of the frames or multi-frames that make up each signal,
Overhead of the backward main signal for determining the delay amount of each of the signal relay transmission devices 3 to 5 on the protection line, that is, the 1-system transmission line 22 side, and returning the control information based on this delay amount to the transmission side terminal device 1 It is inserted in the portion and sent to each of the signal relay transmission devices 3-5.

The delay amount set for each of the variable delay circuits 11 to 18 is the maximum path length difference to be absorbed, that is, the received signal phase difference, in order to reduce the deviation of the hardware scale in a specific variable delay circuit. Is a value obtained by almost evenly distributing the maximum value of the variable delay circuits of the signal relay transmission devices constituting the transmission lines of the respective systems.

Each of the signal relay transmission devices 3 to 5 analyzes the overhead part of the backward main signal to extract the inserted control information, and based on this, the delay amount of the variable delay circuits 11 to 13 of its own device. To set.

In this way, the delay amount on the protection line, that is, on the side of the system 1 transmission line 22 is adjusted, and the receiving side terminal station device 2
After confirming that the received signal phase matches the working line and the protection line, the changeover switch 20 is operated to complete the non-instantaneous interruption switching process.

[0019]

As described above, according to the present invention, each signal relay transmission device is provided with a variable delay circuit, and based on the phase difference between the current line and the standby line measured by the receiving side terminal device,
Since the delay amount in each variable delay circuit on the protection line side is controlled by the control information, the delay amount required for adjusting the phase difference is distributed to each signal relay transmission device. Therefore, in the hitless switching method in the digital communication network, a special effect that the biased facility load on a specific device among the transmission devices configuring the network can be reduced is obtained.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing a hitless switching method according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing a conventional hitless switching method.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 transmitting side terminal device 2 receiving side terminal device 3-10 signal relay transmission device 11-18 variable delay circuit 19 phase difference measuring circuit 20 changeover switch 21 0 system transmission line (working line) 22 1 system transmission line (spare line )

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[Procedure amendment]

[Submission date] April 22, 1994

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be amended] Claims

[Correction method] Change

[Correction content]

[Claims]

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0008

[Correction method] Change

[Correction content]

[0008]

In order to achieve such an object, a method of switching without interruption according to the present invention provides a signal relay transmission device for relaying a signal with an arbitrary signal delay amount according to control information. The terminal device on the receiving side measures the received signal phase difference between the working line and the protection line, and delays a predetermined delay to a predetermined signal relay transmission device according to the measurement result. The control signal that indicates the amount is sent to adjust the received signal phase difference, and when the phase of the received signal on the working line and the protection line match, the line is switched from the working line to the protection line. is there. In addition, the transmitting side terminal device
Multiple signal relay transmission devices between the
It has multiple signal relay transmission equipment as well as the existing working line.
It is connected to the protection line in parallel and
Measure the phase difference between the signals received from the protection line and the protection line
Switching between phase difference measurement circuit and working line and protection line
Provided with a changeover switch and passes through each signal relay transmission device
A variable delay circuit that controls the amount of signal
And the received signal phase difference between the protection line and the protection line
Adjust the variable delay circuit based on
After confirming that the received signal phase matches the line, switch
It is designed to operate Ji.

Claims (1)

[Claims] 1. A signal relay transmission device for relaying a signal is provided with a signal delay means capable of arbitrarily setting a delay amount of the signal according to control information, and the terminal device on the receiving side has a working line and a protection line. Of the received signal phase difference is measured, and control information for instructing a predetermined delay amount to the predetermined signal relay transmission device is transmitted according to the measurement result to adjust the received signal phase difference, A non-instantaneous switching method in a digital communication network, characterized in that the line is switched from the working line to the protection line when the phase of the received signal matches the phase of the protection line.