JPS6399632A - Connecting method for local area network - Google Patents

Abstract

PURPOSE:To connect between respective stations with optical fiber cables of two cores so as to use in an abnormal state by connecting an optical fiber tor transmission and an optical fiber for return between the respective stations to the end station. CONSTITUTION:As for the respective stations LS2-LS4 which is the end station, the optical fibers 15a-15c for transmission and the optical fibers tor communica tion are connected between one station and the next station where data should be transmitted and in the normal state a loop back from the optical fibers 15a-15c for transmission to the optical fibers 16a-16c for return is executed at the end station LS4 and in the abnormal state the loop back 8 from the optical fiber 15b for transmission to the optical fiber 16b for return is executed at the station LS3 which positions before abnormality occuring spot. Thus plural stations sequentially arranged in a line can be connected the optical fibers of two cores and they can be used in the abnormal state.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a local area network (hereinafter referred to as LAN) connection method for connecting a plurality of stations installed sequentially using optical fibers for data communication. be.

[Prior Art] FIG. 3 is a schematic configuration diagram showing an example of a conventional LAN connection method. In Figure 1, a master station (hereinafter referred to as MS) 1 and a local station (hereinafter referred to as L
(referred to as S) 2 to 4 are installed in a ring, and optical fibers 5a to 5d are connected between each station, and the optical fibers 5a to 5d form a normal loop,
ing.

Further, optical fibers 68 to 6d are also connected between each station, and the optical fibers 6a to 6d form a packed loop.

During normal operation, data from the MSI is transmitted through the optical fibers 5a to 5a.
It is flowing through the normal loop of 5d. At this time, light on which no information is carried is transmitted in the pack loop of the optical fibers 6a to 6d in the opposite direction to the normal loop, and is kept in an idling state. By creating such an idling state, it is possible to detect abnormalities in each station or the optical fiber cable! : Can be done.

FIG. 4 is a schematic configuration diagram of a contact state when an abnormality occurs in the conventional connection force method similar to that shown in FIG. 3.

In FIG. 4, the end fiber 51) shows a state of sugar in which the disconnection 1-1 abnormality has occurred. L S3 determines that the normal loop power is cut off, and internally switches the output of its own loop to the input side of the normal loop. Further, in L S 2, it is determined that the human power of the pack loop has been cut off, and the output of its own normal loop is switched to the human power of the buck loop within it.

LS2 and LS3 below! By the Jl switching operation, a data loop as shown in FIG. 4 is secured, and all lines can be restored instantly. In addition, at this time, it is also possible to simultaneously check on the monitor display of the MS where the abnormality has occurred.

[Problems to be solved by the invention] However, with such conventional LAN connection methods,
For example, like a station set up along a railroad track,
Problems arose when connecting stations installed in a line. FIG. 5 is a schematic configuration diagram for explaining such problems.

In FIG. 5, MSI and I-S 2 to 4 are installed in a line in sequence, with an optical fiber 5a between MSI and LS2, an optical fiber 5b between LS2 and LS3, Optical fiber 5 between LS3 and LS 4 Optical fiber 5 between Cs LS 4 and MSI
d are connected respectively. In addition, as optical fibers for bucklube, there is an optical fiber 6d between MSI and LS4, a tip fiber 6c between LS4 and LS3, and an optical fiber 6c between LS4 and LS3.
Between 3 and LS2 is a fiber 6b, LS2 and MSI
An optical fiber 6a is connected between them.

As shown in Fig. 5, when trying to connect multiple stations installed in a linear manner using the conventional connection method, it is difficult to connect optical fibers 5d or 6 (j) which have very long distances. Optical fibers must be used.Furthermore, if such end fibers are to be accommodated in one cable, it is necessary to use at least a four-core optical fiber pulley. As the number of fibers in the end fiber cable increases, problems such as increased cost arise.

As shown in Fig. 6, if the fiber at the end of the pack loop + T-pull is not provided, it is possible to connect the two fibers by connecting the optical fiber...1
Once an abnormality occurs due to a failure in the line 9 station, all stages 11 stop operating, and there is also the problem that it is difficult to detect the location where the abnormality has occurred.

The purpose of this invention is to provide a LAN connection method that connects a number of stages of stations installed in a linear manner using two-core optical fibers, and that can cope with the occurrence of an abnormality in one of the stations. be.

[Means for solving the problem] In the LAN connection method of the present invention, the terminal station
A transmission optical fiber and a communication destination fiber are connected to the valley station up to the next station to which data is to be transmitted. During normal operation, the terminal station connects the transmission optical fiber to the return fiber. A loopback is performed to the optical fiber, and in the event of an abnormality, a loopback is performed from the transmitting optical fiber to the return optical fiber at a station located in front of the location where the abnormality occurs.

[Function] In the connection method of the present invention, the transmitting optical fiber and the return destination fiber are connected between each station up to the terminal, so it is possible to connect the three stations with a two-core optical fiber cable. can.

Further, in the connection method of the present invention, when an abnormality occurs, a loopback is performed at a station located before the abnormality occurrence point, so that the stations up to the abnormality occurrence point can be used even in the abnormality. Moreover, for this reason, the location where an abnormality occurs can be detected at the master station.

[Embodiment] FIG. 1 is a schematic diagram showing an embodiment of the present invention. MSI and L S 2 to 4 are sequentially installed in a linear manner. There is a transmission optical fiber 1 between the MSI and LS2.
5a, between LS2 and LS3 is the transmission optical fiber 1.
5b, transmission optical fiber 15 between LS3 and LS4
e are connected to each other. Also, LS 4 and LS
There is a return optical fiber 16c between LS3 and LS2.
(3 optical fiber 16b, LS2 and MSI
A return optical fiber 16a is connected between the two.

Figure 1 shows the normal state, where at L S 4, which is the terminal station, a loopback is made from the transmission optical fiber to the return optical fiber, forming a loopback path 7. .

During normal operation, data from the MSI is transmitted through the transmission optical fiber to the terminal LS4, and is returned to the MSI through the return optical fiber.

FIG. 2 shows a connection state when an abnormality occurs in the LAN shown in FIG. In FIG. 2, an abnormality occurs in LS4 at the terminal station, and a loopback path 8 is formed in LS3 located before LS4. In this state, data from the MSI is transmitted to LS3 through the transmission optical fiber,
The signal is looped back through the loop path 8 and returned to the MSI through the return optical fiber. [,Therefore, either LS4 where the failure has occurred cannot be used, or each station up to LS3 can be used.

Also, the data sent back to MSI confirms that the data has been transmitted to LS3, so LS3
The occurrence of an abnormality is detected on the far end side.

In addition, in the case of an abnormality due to a break in the optical fiber, the
It works in the same way as John's abnormality.

In the following description, one transmission optical fiber and one return optical fiber are illustrated, but there may be one (or several).

[Effects of the Invention] In the connection direction of the LAN of the present invention, each station up to the end station is connected to a transmission optical fiber and a return optical fiber to the next station to which data is to be transmitted. Therefore, the optical fiber used for connection can be shortened, and a two-core optical fiber cable can be used.

Furthermore, in the connection method of this invention, if an abnormality occurs,
Since loopback is performed at the station located before the location where the abnormality has occurred, each station up to the location where the abnormality has occurred can be used. Furthermore, since the master station confirms that the data has been transmitted to the station located before the location where the abnormality has occurred, it is also possible to detect the location where the abnormality has occurred.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram for explaining one embodiment of the present invention. FIG. 2 is a schematic configuration diagram showing a connection state when an abnormality occurs in the LAN shown in FIG. 1. FIG. 3 is a schematic diagram showing an example of the conventional LAN connection method. FIG. 4 is a schematic configuration diagram showing a connection state when an abnormality occurs in the LAN shown in FIG. 3. FIG. 5 is a schematic configuration diagram showing a connection state when a plurality of stations sequentially installed are connected using the conventional connection method shown in FIG. FIG. 6 is a schematic configuration diagram showing a connection state when a plurality of stations installed in sequence are connected by another conventional connection method. In the figure, 1 is the master station, 2°3.4 is the local station, 7 and 8 are the loopback paths, and 15
a, 15b, 15c are transmission optical fibers, 16a, 16
b, 16c shows the return optical fiber 7.

Claims (1)

[Claims] (1) A local area network connection method for data communication by connecting multiple stations installed sequentially using optical fibers, in which each station up to the end station is connected to the next station to which data is to be transmitted. The transmitting optical fiber and the return optical fiber are connected between the two terminals, and during normal operation, a loopback is made from the transmitting optical fiber to the return optical fiber at the end station, and when an error occurs, the station located before the location of the error occurs. A method for connecting a local area network, characterized in that a loopback is performed from a transmission optical fiber to a return optical fiber.