JPH0319439A - Monitoring system for multiplex transmission line - Google Patents

Abstract

PURPOSE:To improve the reliability with a simple constitution by assigning monitoring information to a section overhead on the frame format of a main signal, transmitting the main signal together with the monitoring information and allowing a terminal station repeater at a reception side to separate and analyze the monitoring information from the section overhead of the main signal. CONSTITUTION:A terminal station repeater TA is provided with an F1 generating circuit 21 receiving monitoring information SA and assigning it to a byte F1, and a terminal station repeater TB is provided with an F1 demultiplexing circuit 32 demultiplexing the byte F1 and an F1 decoding circuit 33 decoding the demultiplexed signal. Moreover, an intermediate repeater Ri is provided with a frame generating circuit 14 generating a frame according to the output of an alarm collection circuit 13 and an F1 generating circuit 15 generating the byte F1. A selection circuit 16 selects whether the output of the frame generating circuit 14 transmitting a signal from a preceding relay section to a succeeding relay section as it is or the output of the F1 generating circuit 15 is transmitted to the succeeding relay section according to an alarm. Thus, the device constitution is simplified and the reliability is also improved.

Description

[Detailed description of the invention] [Industrial application field] The present invention is utilized for digital multiplex communication.

The present invention is suitable for use in monitoring multiple transmission lines using optical fiber cables.

The present invention is based on the International Telegraph and Telephone Consultative Committee (CCITT) Recommendation G. 707. G. It is used for multiplex transmission systems using interfaces compliant with G.708, G.709, and others.

The present invention relates to a system in which the operating state of an intermediate relay device installed in the middle of a transmission path is monitored by a terminal relay device installed at the receiving end of the transmission path. By allocating and transmitting signals according to a format, a main signal path and a separate signal path connecting each intermediate relay device are unnecessary.

[Conventional technology]

To monitor a digital multiplex transmission line that includes terminal repeaters installed at both ends of one transmission line, and a plurality of intermediate repeaters located in the middle of the transmission line that regenerate and relay signals transmitted to that transmission line. Each intermediate relay device includes means for generating monitoring information from the received signal and the operation information of the own device, and means for transmitting the monitoring information generated by the means to the terminal relay device. These methods have been put into practical use in various forms. Typical examples are Miura,
Katagiri, Yamaguchi et al., "Design and Characteristics of rF-400M Monitoring and Control System" published by Nippon Telegraph and Telephone, Research and Practical Application Report, Vol. 32, No. 3, pp. 609 et al. (1983).

An overview is shown in FIG. 6. The main signal is transmitted from the terminal station relay device TA to the terminal station relay device Ta via the optical fiber.
A large number of intermediate relay devices R1 to Rn are connected in cascade to this optical fiber to form a transmission path. In order to monitor this transmission path, a supervisory control device SVA1SV! is installed at each terminal relay device and each intermediate relay device. l and S V+
~S V n are arranged, these monitoring and control devices are coupled to the cable using an electric wire implemented as an intervening line of optical fiber, and monitoring information is transmitted to this intervening line. In the above example of the F-400M system, the supervisory control device SV. , SVa is configured to perform polling to collect information.

[Problem to be solved by the invention]

In this conventional method, in addition to the optical fiber that transmits the main signal, another intervening line is required, and at each intermediate repeater installation location, it is necessary to connect the monitoring and control equipment and supply power for its operation. Yes, it was a complex structure.

The present invention improves this by providing a system that does not require complicated equipment to be installed at the installation location of the intermediate relay device, and does not require a path for transmitting monitoring information in addition to the path for the main signal. With the goal.

That is, an object of the present invention is to provide a monitoring method that can improve reliability with a simple structure.

[Means to solve the problem]

The present invention is characterized in that the monitoring information is allocated to the section overhead on the frame format of the main signal and transmitted together with the main signal, and the terminal relay device on the receiving side separates and analyzes the monitoring information from the section overhead of the main signal. shall be.

The conventional method is characterized in that the monitoring information is transmitted together with the main signal and does not require a separate device or path for transmitting the monitoring information.

[Effect]

International Telegraph and Telephone Consultative Committee (CCITT>Recommendation G.70
7, G, 708, G. In addition to 709, the frame format of the signal is defined, and its section overhead has room for multiple bytes to be used on the transmission path. Necessary monitoring information can be efficiently allocated here.

Recommendation G. 707, G, 708, G. 709
Detailed information can be found in the ``Blue Book'' published by the International Telecommunication Union.

〔Example〕

FIG. 1 is a block diagram of an embodiment of the present invention. In other words, in the method according to the embodiment of the present invention, there are terminal repeaters TA and Tg installed at both ends of one transmission line, and a large number of intermediate repeaters installed in the middle of the transmission line for reproducing and repeating signals transmitted to the transmission line. R, to Rn. Each intermediate relay device R
1 to Rn are provided with means for generating monitoring information from the received signals and the operation information of their own devices.

FIG. 2 is a block diagram illustrating in detail the structure of one intermediate relay device Ri of the terminal relay devices TA and TI in the configuration of the above embodiment. In other words, in this method, as a means for generating monitoring information from the received signal and the operation information of the own device, frame 1, which detects signal interruption due to loss of frame synchronization, is used.
It includes a synchronization circuit 11, an error rate detection circuit 12 that detects that the error rate exceeds a predetermined value, and an alarm collection circuit 13 that collects these detection outputs.

Here, the apparatus of the present invention is configured to allocate this monitoring information to a section overhead on the frame format of the main signal. Further, the receiving side device T of the terminal station l1 device is configured to separate and analyze the monitoring information from the section overhead of the received main signal. That is, the terminal relay device TA is equipped with an F1 generation circuit 21 that manually assigns the monitoring information SA to pi}Fl, and the terminal relay device TB is equipped with an F1 separation circuit 3 that separates this pi}Fl.
2 and the F1 decoding circuit 3 that decodes the separated signal.
Equipped with 3. Further, the intermediate relay device ffiRi includes an F1 generation circuit 15 that generates a frame, a generation circuit l4, and a frame }Fl according to the output of the alarm collection circuit 13. The selection circuit 16 transmits the signal from the previous relay section as it is to the next relay section, transmits the output of the frame control circuit l4 to the next relay section, and transmits the output of the Fl control circuit 15 to the next relay section. The system is to select one of the following depending on the alarm.

Next, a method of allocating monitoring information to the section overhead on the frame format of the main signal will be explained in detail.

Figure 3 shows CCITT Recommendation G. 15 shown in 708
The section overhead of the frame format of the 0M signal (STM-1> Byte AI, A2, STM-1 identification number pi}Cl
, Section section error Error monitoring byte 8k Section section switching control pi} Kl, K2, data communication pi}
Bytes other than Di-03, voice meeting pie}El can be used in the present invention. Part-time jobs marked with an x mark are available according to the rules of each country. Here, an example using the F1 byte will be explained.

(Hereinafter referred to as the margin of this page) Table 1 (Symbols in Figure 3) Assign numbers 1 to 6. Tables 2 and 3 are structure tables for each byte.

Table 2 (see FIG. 4) Table 3 (see FIG. 4) FIG. 4 shows an example of bit allocation using one F1 byte. In this example, the state of the transmission path input to the intermediate relay device is "normal" and "the error rate is below a certain threshold (the error rate is calculated within the device using the above byte 81)" signal. 4, “Bit error detected (bit error is detected by byte B1 above)”
Define the state. Bytes b3, b4, b5, b6, b7
, b8 is assigned to the identification code of the intermediate relay device that transmits it, and at most this allows the receiving end to identify the failed relay section. FIG. 5 shows an example in which there are four relay sections, and as shown by the cross marks in FIG. The figure shows a case where a signal is cut off between R2 and R2. At this time, different identification codes are assigned to the intermediate relay devices R, to R7 in advance.
A % The terminal relay device Ts should be assigned a different identification code from the intermediate relay device, or “63” on the transmitting side and “63” on the receiving side.
0" may be fixed.

To explain this operation, first, the terminal relay device TA assigns predetermined values to bytes bl and b2 between "00" (normal) and b3 to b8 and transmits them. Since the human power side of the intermediate relay device R3 is normal, it transmits it as is to the output side. Since the intermediate relay device R2 detects a signal disconnection, pi}
"10" (signal disconnected) and pi} b3 to b8 are assigned numbers assigned in advance to the intermediate relay device R2 and transmitted. This signal interruption can be detected by making it impossible for the intermediate relay device R to reproduce the block received from the intermediate relay device R.

Since the human power side of the intermediate relay device WR3 is normal, the intermediate relay device WR3 allows the signals }bl to b8 to pass through as is, as in the case of the intermediate relay device R. The terminal relay device TA is bi}bl~b
8, it can be seen that the input side of the intermediate relay device R2 has a signal disconnection.

As described above, according to the present invention, when a line abnormality such as a signal interruption or an increase in error rate occurs, the contents and the number of the intermediate relay device can be notified. In this method, 2
If a line abnormality occurs at more than one location at the same time, only the abnormal portion closest to the terminal relay device on the receiving side can be detected.

FIG. 5 is another example of bit allocation for one byte using the F1 byte.

Table 4 (see Figure 5) Table 5 (see Figure 5) eliminates the need to rely on intervening lines for special lines for transmitting monitoring information, and reduces equipment configuration and intermediate relay equipment. Power supply to the installed monitoring and control device is simplified, and reliability can be improved as well. Furthermore, the number of man-hours required for line installation can be reduced.

In this example, in addition to the information on the manual side of the transmission path, the state of the intermediate relay device itself is defined. At this time, the number of intermediate repeater sections that can be specified is reduced compared to the above example, but
The status of the intermediate relay device section can be known in more detail. If you need to know more details, you can create a multi-frame in one byte or use multiple bytes.

〔Effect of the invention〕

As explained above, according to the present invention, it is possible to allocate the monitoring information of the intermediate relay device to the section overhead on the frame format of the main signal.

[Brief explanation of drawings]

FIG. 3 is a block diagram of the system according to the embodiment of the present invention. FIG. 2 is a block diagram illustrating in detail the configuration of a terminal relay device and an intermediate I# device according to an embodiment of the present invention. FIG. 3 is a diagram showing an example of the structure of a section overhead according to an embodiment of the present invention. FIG. 4 is a diagram showing an example of allocation of the F1 byte. FIG. 5 is a diagram showing another example of F byte allocation. FIG. 6 is a block diagram of a conventional system.

Claims (1)

[Claims] 1. A terminal relay device installed at both ends of one transmission line;
The transmission path includes a plurality of intermediate relay devices that regenerate and relay the signals transmitted on the transmission path, and each intermediate relay device generates monitoring information from the received signal and the operation information of its own device. In the multiplex transmission path monitoring method, the system includes a means for transmitting monitoring information generated by the means to the terminal relay device, wherein the terminal relay device and the intermediate relay device transmit the monitoring information. means for allocating the monitoring information to the section overhead on the frame format of the main signal transmitted to the transmission path, and the receiving side device of the terminal relay device is configured to separate the monitoring information from the section overhead of the main signal to be received. A method for monitoring multiplex transmission paths, characterized by comprising means for analysis.