JPH0583279A - Local area network - Google Patents

Abstract

PURPOSE:To execute a transmission without hit even when a fault is generated by multiplexing of a transmission line and improvement of an interface part being incidental thereto. CONSTITUTION:A transmission line A is subjected to multiplexing, and to plural transmission lines A consisting of optical fibers, interface parts C-H are connected like a loop. Also, a part of the transmission line side of the interface parts C-H is subjected to multiplexing, and the transmission line A subjected to multiplexing is used as a multi-route. The transmission line A is connected to an optical interface part 2, and a received optical signal is converted to an electric signal, and selected and outputted to a packet processing part 3. To the processing part 3, a line set part 4 is connected, whether received data is normal or abnormal is decided therein, and that which is correct is passes to a terminal machine. Accordingly, even in the case a fault is generated in one of the transmission line A, the interface part 2, and the processing part 3, and an error is generated in the received data, data passing through the multi-route, being a substitute therefor can be selected immediately.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION This invention relates to local area networks (LANs), and more particularly to fault tolerant
It is a proposal for LAN.

[0002]

[Prior Art] LAN applied to factory operation systems and public institutions
Therefore, high reliability is required. In order to meet this demand, a system has been adopted in which a standby system is provided on the transmission line in addition to the active system and the system is switched to the standby system when a failure occurs.

[0003]

However, in such a system, there is a problem that the transmission path is momentarily interrupted when switching is performed at the time of failure. The present invention has been made in order to solve the above-mentioned problems of the prior art. Due to the multiplexing of transmission lines and the improvement of the interface unit accompanying this, local transmission is possible without interruption even when a failure occurs. The purpose is to provide an area network.

[0004]

A local area network according to a first aspect of the present invention is a local area network in which a plurality of data devices are connected to a transmission line through interface units, respectively, wherein the transmission line is N multiplexed. In addition, a part of the transmission line side of the interface unit is N-multiplexed, and the multiplexed transmission line is connected to the interface unit for use as multiple routes.

A local area network according to the second invention comprises an N-multiplexed transmission line and an interface unit connected between the transmission line and a data device and having an N-multiplexed packet processing unit. The multiplexed transmission line provided is connected to the interface unit for use as a multi-route, and the interface unit receives data from the transmission line by means for packetizing data from the data device and transmitting it to the multi-route transmission line. Means to monitor packets,
Means for selecting normal data as a result of monitoring and sending it to the data device.

A local area network according to a third aspect of the present invention is characterized in that a connection section of the interface section with the transmission line has a redundant configuration.

[0007]

According to the first and second aspects of the present invention, even if a failure occurs in any of the multi-route transmission paths and an error occurs in the received data, the alternative data via the multi-route is immediately selected. be able to.

[0008]

1 is a system structure diagram of a local area network of the present invention, and FIG. 2 is a block diagram of an interface section. The transmission line A is multiplexed. The interface units C to H are connected in a loop type to a plurality of transmission lines A formed of optical fibers. A data device such as a host computer (not shown) or a terminal K is connected to each interface unit.

Reference numeral 2 denotes an optical interface section, which is duplicated on both the receiving side on the left side and the transmitting side on the right side in FIG. First, looking at the receiving side, 2 of transmission line A
The book is connected to the optical / electrical conversion units 201, 201, and converts the received optical signal into an electric signal and inputs it to the selector 203.
Optical / electrical converters 201, 201 are various alarms for received data
(Light interruption, etc.) is detected and given to the selection control unit 202. Based on this, the selection control unit 202 issues a control signal to the selector 203 to selectively output one of the two inputs to the packet processing unit 3.

The output of the selector 203 is a clock transfer unit 301.
The received data (according to the clock of the transmission path) is transferred to the clock generated by the internal clock generator 302, and destuffing is performed for synchronization. The clock output from the clock generator 302 is also used as the master clock of this interface section. Therefore, the clock continues to be emitted even when reception is interrupted.

The received data whose clocks have been changed is input to the received packet processing unit 303, where the header of the received packet is examined, and reception / relay determination is performed. When the packet is relayed, it is sent to the repeat unit 304, and the received packet is buffered here. Then, at the timing of the packet header on the transmitting side, which will be described later, this is relayed in synchronization with the signal received from the packet transmitting unit 305.

The received packet is input to the reception arbitration units 307, 307 .... The reception arbitration units 307, 307 ... Store a large number of line setting units 4, 4, ..., However, the reception arbitration of the line setting unit 4 is first performed after the reception arbitration units 307, 307. I do.

The line set unit 4 is for selecting multiplexed data, and the transmission line other than the two transmission lines connected to the optical / electrical conversion units 201, 201 shown in the figure similarly uses the optical interface unit 2 and packet processing. The data from the reception arbitration unit 307 is input via the unit 3. First, the received packet is sent by the line clock transfer unit 401 to the line set unit 4
Can be transferred to the clock. This clock is created by the master clock.

The received packet is also processed by the received packet processing unit 40.
It is input to 2 and confirms the sequence number and source address and CRC check from the header information of the received packet, and discards the packet. In addition, the number of received packets is counted for each route, and PLL is performed according to the amount of data.

The multiplexing selection unit 403 is for selecting multiplexed reception data, and the reception packet processing unit 402
The state of the received data is displayed as a flag according to the processing result in (1). In addition, data is written here according to the sequence number to absorb the phase difference of the received data via each route, and normal data is read while observing the flag of the data of the same phase to perform multiplexed selection.

Reference numeral 5 is a line set (LS) switch section,
The select line 501 selects the multiplexed line set unit 4. The selection control is performed by the selection control unit 502, which receives a status flag corresponding to the data from the line setting unit 4 and selects the line set to which normal data is transmitted. The reception data selected in this way is sent to the terminal K. Reference numeral 6 in FIG. 1 is a multiplexing device for sharing one line setting unit 4 by a plurality of terminals K, K ...

Next, looking at the transmitting side, the data given from the terminal K is inputted to the transmission control section 404 of the multiplexed line setting section 4 via the transmitting section 503 of the LS switch section 5. The transmission control unit 404 packetizes the input data and transmits a plurality of packet processing units 3 via the transmission buffers 405, 405.
To the transmission arbitration unit 308.

The transmission arbitration units 308, 308 ... Are line set units 4.
After the transmission arbitration is performed, the arbitration between the transmission arbitration units 308, 308 ... Is performed and the packet is transmitted by the transmission permission signal generated by the arbitration. The packet transmission unit 305 gives the timing of the header to the repeat unit 304 for transmitting the relay packet, while passing the packet to the multiplexing unit 306. The multiplexing unit 306 adds stuff or the like to the packet of data to be transmitted and multiplexes it into the frame on the transmission path A, and the transmission unit 204 of the optical interface unit 2
An optical signal is sent from the electric / optical conversion units 205, 205 to the transmission line A via the.

FIG. 3 is a block diagram showing an example of the case of duplication in order to make it easier to understand the manner of multiplexing of the interface section. Therefore, the transmission line A is also duplicated and used as two routes. The optical transmission line A ₁ (A ₂ ) is connected to the optical interface unit 2 ₁ (2 ₂ ),
A packet processing unit 3 ₁ (3 ₂ ) is connected to the optical interface unit 2 ₁ (2 ₂ ) and its reception arbitration unit 30
7 ₁ , (307 ₂ ) and the transmission arbitration unit 308 ₁ , (308 ₂ ) are connected to the line set unit 4 common to the two systems, and the terminal K is connected to the line set unit 4.

2 and 3 are different in the configuration of the optical interface section. In the configuration of FIG. 2, the optical / electrical conversion section and the electric / optical conversion section are duplicated to form a redundant configuration.
In FIG. 3, such a redundant configuration is not used.

In the case of the configuration shown in FIG. 3, the transmission line A ₁
And / or the normality / abnormality of the two data received via A ₂ is judged by the line setting unit 4 and the correct one is given to the terminal K. Therefore, even if one of the transmission paths A ₁ and A ₂ , the optical interface units 2 ₁ and 2 ₂ and the packet processing units 3 ₁ and 3 ₂ fails, the data can be switched and received with virtually no interruption. ..

On the other hand, let us consider the transmission system. The data output from the terminal K passes through the line set unit 4 and the packet processing unit 3 ₁ .
3 ₂ reaches the, where it is packetized gradually sent out from the optical interface unit 2 _1, 2 ₂ to the transmission line A _1, A _2. When the data is normally transmitted by two routes, the receiving side receives the normal data even if some failure occurs in one data route as described above. Since the transmission system is duplicated, even if a failure occurs in one of them, normal data reception is ensured as long as there is no failure on the receiving side.

[0023]

As described above, according to the present invention, a highly reliable fault tolerant LAN can be realized.

[Brief description of drawings]

FIG. 1 is a system configuration diagram of the present invention.

FIG. 2 is a block diagram of an interface unit.

FIG. 3 is a block diagram of a duplex interface unit.

[Explanation of symbols]

A, A ₁ , A ₂ Transmission line 2, 2 ₁ , 2 ₂ Optical interface unit 3, 3 ₁ , 3 ₂ Packet processing unit 4 Line set unit

Claims (3)

[Claims] _1. A local area network in which a plurality of data devices are connected to transmission lines (A, A ₁ , A ₂ ) via interface units (C to H), respectively,
The transmission lines are N-multiplexed, and a part of the interface units (C to H) on the transmission line (A, A ₁ , A ₂ ) side is N-multiplexed.
The multiplexed transmission lines (A, A ₁ ,
A ₂ ) is a local area network characterized by being connected to interface sections (C to H) for use as multiple routes. 2. N-multiplexed transmission lines (A, A)₁, A₂)
And the transmission line (A, A ₁, A₂) And the data device
Connected and N multiplexed packet processing units (3,
Three₁, 3₂And an interface unit (C to H) having
And a multiplexed transmission line (A, A₁, A₂) Is multi-rou
Interface (C to H) to be used as a
The interface part (C to H) is data
Multi-route transmission line by packetizing data from devices
(A, A₁, A₂) And a transmission line (A, A
₁, A₂) Means to monitor packets received from
Means of selecting normal data as a result of visual observation and sending it to the data device
And a local area network characterized by
Ku. 3. The local area network according to claim ₂ , wherein the connection sections of the interface sections C to H with the transmission paths A, A ₁ and A ₂ have a redundant configuration.