JPS5980043A - Loop transmitter - Google Patents

Abstract

PURPOSE:To reorganize a line in a smooth and quick way, by checking the state of a separated faulty area by an adjacent nondefective transmitter, then transmitting normally the transmittable information to all transmitters when the transmission is made possible and a token is received. CONSTITUTION:Transmitters 10 are connected with transmission lines of R and L lines 11 and 12 having opposite directions to each other. The transmission is usually carried out through the line 11; while the loop-back transmission is performed when a fault arises at the line 11 or a transmitter 10. At the same time, the faulty area 14 is separated. The transmitters 10 have exactly same functions, and the right of transmission is set up by taking just a single token existing in the system. The transmitter 10 having the token transfers the token to the next transmitter 10 via the line 11 when the transmission of data is over.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a transmission device that has a loop-shaped transmission path and controls data transmitted and received via the transmission path.

[Technical background of the invention]

In a system where a transmission path is configured in a loop and multiple transmission devices are connected to it, if each transmission device sends data to the transmission path at will, this data will cause interference on the transmission path. The transmission right must be controlled by some means.

There are several methods for this, but the transmission device according to the present invention uses conventionally known token delivery methods.
n passing ) method is adopted. In this method, there is only one transmission right called a token in the system,
Only the transmission device that holds this can transmit. A transmission device that does not hold a token is only allowed to receive transmitted data from a transmission device that does have a token.

However, it has not been generally established how to generate only one token in a system and how to transfer this token between transmission devices.

In the conventional device, a special transmission device for monitoring and control is provided in the transmission path, and this device generates tokens and controls sending and receiving the tokens to and from each transmission device.

[Problems with background technology]

However, if there is an abnormality in this device or the transmission line connected to it, the system will stop, so a backup device is essential, and control between these two devices becomes complicated.

In addition, due to a failure of the transmission equipment, it may be disconnected,
The monitoring device also performs control to incorporate the fault recovery into the transmission system, but since the faulty device and the monitoring device are separated by a distance, this often causes operational inconvenience.

As described above, a transmission system in which transmission control is performed at one location has problems in system reliability and operational operability.

[Purpose of the invention]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a loop transmission device that overcomes the drawbacks of conventional devices.

[Summary of the invention]

The present invention provides a transmission device using a token passing method in which a plurality of transmission devices are connected through a double loop-shaped transmission path, and only the transmission device holding one token in the entire system for controlling transmission rights can transmit. A part of the transmission device or the transmission line is disconnected and loopback transmission is performed via the double loop transmission line. This is a round-trip transmission in which the involved transmission equipment and the transmission equipment that were previously separated are transmitted through a loop-shaped transmission line that is doubled by one inch, to all the transmission equipment that can transmit the same data. In addition, the loop transmission device is one of the transmission devices on both sides adjacent to the disconnected portion, and the transmitter that can investigate the status of the adjacent disconnected portion It is a device.

[Embodiments of the invention]

An embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a system configuration diagram using a loop transmission device in this embodiment. The transmission device 10 has an R line 11. whose data transmission directions are opposite to each other. They are connected by a transmission line called L line 12 and have a double loop structure. Transmission is normally performed through the R line 11, and when an abnormality occurs in the R line 11 or the transmission device 10, the L line 12 is used for loopback transmission and the abnormality occurring portion 14 is disconnected.

The transmission devices according to the present invention each have exactly the same functional cost. The transmitter establishes a token delivery system by receiving a token, which exists only once in the system. When the transmission device 10 holding the token completes the transmission of the data to be notified to the transmission device 10 in the pond,
The token is passed to the next transmission device 10 via the line 11.

Here, the former device will be referred to as an upstream station, and the latter device will be referred to as a downstream station.

Also, the transmission device that holds the token is called a mask, and all other devices are called slaves.

Therefore, there is no device specially provided for controlling transmission. When the transmission device 10 that has received the token has no data to transmit, it immediately passes the token to the downstream station.

When all transmission devices do not have data to send,
Only tokens are circulating on the transmission path.

The transmission format is data transmission between special transmission devices.
n transmission, and broadcast transmission in which all slave transmission devices receive data sent from the mask transmission device.
Both round transmissions are possible. These identifications are performed in the third portion SA of the transmission frame 13, which will be described later.

In n:n transmission, the slave transmission device 1o takes an acknowledgment that it has correctly received the data. On the other hand, in broadcast transmission, no acknowledgment is received from each slave device. When the transmitted data returns via all the slave devices, the mask device compares the received data with the transmitted data, and if they match, it considers the data to have been correctly transmitted.

Figure 1 (D) shows the case where the transmission line is in failure 1. This shows the transmission format when

Since the transmission line has a double loop configuration, the transmission equipment 10 (STN equipment and 5TN1+) at both ends of the failure point 14
1) is the R line 11. An example is shown in which data received on the L line 12 is transmitted to the opposite line.

FIG. 2 is a diagram showing the format of data flowing through a transmission path, and the format of data transferred within the transmission device 10 will be explained with reference to this diagram.

The transmission frame 13 consists of six parts (referred to as fields).

The first part is the command OMD. This is to identify all the contents of the transmission frame 13, and is used for testing (TEs).
T)', line configuration (0NF), text (TEXT
O), playback text (TEXTI).

Token (TOKK)), Acknowledgment (AC)
K).

Either negative response (NAO) is entered.

The second part SA is for specifying the transmission device that should receive the transmission frame, and only when this value is noI+ indicates that the transmission frame is received by all transmission devices, that is, broadcast transmission.

The third part PA represents the address of the transmitter of the mask transmitting the transmission frame.

The fourth part N specifies the entire data length of the text part TEXT that follows.

The fifth part, the text part TEXT, is where information is entered as soon as the mask is transmitted to the system.

The final check section BCC is provided to detect bit errors in the transmission frame.

FIG. 3 is a diagram showing the internal structure of the transmission device according to the present invention.

The flow of transmission data within one transmission device 10 will be explained with reference to FIG. 3.

First, the entire operation will be explained when the device is in the Nureve state and the contents of the second portion OMD of the transmission frame 13 are T, FiXTO, and TEXTl.

Since data is sent to the transmission device 10 in the Nurep state via all the R lines 11, the data is written into the reception buffer 101 by the function of the reception control circuit 03.

When the third part 8A of the transmission frame 13 is ``O'' indicating broadcast transmission or is different from the address of the own transmission device, the received data ``(r) is immediately sent to the R line 11 through the transmission control circuit 104. If it is the own address, check whether there is an error in the data written to the reception buffer 101 by using the sixth part BOOi of the transmission frame 13. If it is received correctly, send a message to the transmission control circuit x04. The first part of the transmission frame 13 (1MDiAOK.

The address of the second part SAi mask, i.e. the value of the third part FA of the received transmission frame 13, the third part P
Send A as your address.

Broadcast transmission or data sent to oneself is in the reception buffer 101. This data is transmitted to the equipment connected to the transmission device 10 by the control circuit 108.
Pass it through.

During loopback transmission as shown in FIG. 1(b), data also flows through the L line 12. At this time, the data received from the reception control circuit 106 is directly transmitted to the next transmission device 10 through the transmission/reception control circuit 105i.

Next, the operation when the transmission device 10 in the masked state transmits data will be described with reference to the same drawing.

It is assumed that data to be transmitted has been written from a device connected to the transmission device 10 to the transmission buffer 102 via the reception control circuit 107. Writing to the transmission buffer 102 is possible whether the transmission device flo is in the master or slave state.

The data to be transmitted is the fifth part E of the transmission frame 13.
XT, and the transmission device 10 generates the pool portion.

If this data is to be sent 9 to a specific transmission device, the second part SA of the transmission frame 13 is set to that address. If you want to send it to all slaves, set this value to 0"
and broad canute transmission. When the transmission frame 13 is assembled in this way, the switching switch 109. It is transmitted to the R circuit 11 via the transmission control circuit 104i.

The method of confirming whether the transmitted data has been correctly received is different between broad canute transmission and -n:n transmission. In broad canute transmission, when the data returns via all slave transmission devices, this data is written to the reception buffer 101 via the reception control circuit 103. If this content matches the content of the transmission buffer 102, it is assumed that the transmission was correctly performed.In nun transmission, it is assumed that a transmission frame with an acknowledgment AOK sent from the received slave transmission device is sent.

The masked transmission device that holds the token has the right to transmit. When the mask transmission device completes transmission, it sends the first portion of the transmission frame 13 as OMDi)-Kun-0KFiN to the R line 11 via the transmission control circuit 104i.

The transmission device 10 that has received all the tokens performs the above-described masking process if there is transmission data in the transmission buffer 102 of its own device.

When there is a large amount of data to be transmitted, the received token is immediately sent to the R line 11 via the transmission control circuit 104.

By the way, in order to express the entire operation of one transmission device 1o in a precise and easy-to-understand manner, it is appropriate to divide the operation into a plurality of states and describe the detailed operation and state transition in each state. The transmission device 10 according to the present invention also follows this and will be explained with reference to the state transition diagram shown in FIG.

All transmission devices 10 can take one of the following states. Transitions between states are shown by paths P and j in FIG.

O: Off: Power off state l: Wait: When initialization processing is completed and the self-diagnosis result is normal.

2; Mask check: Sends a test frame, checks operable circuits, and transmits this data to the operable transmission device 10.

Generate a token.

3; Slave check...TestF V-4 i
communication processing.

4: Online mask...Transmission device that holds the token. When there is data to be transmitted within its own transmission device, it is assembled into a transmission frame 13 and transmitted.

5; Online slave...Receives the transmission frame 13 sent from the online mask 4.

6: Down...Line abnormality and power condition.

The operation of the transmission device IO' described above is the operation in a steady state when transmission is normally performed.

FIG. 4 is a diagram showing the operation of the transmission device of FIG. 3 in a state transition diagram.

In the state transition diagram of FIG. 4, the transmission device IO having the transmission right called mask is in the state of online mask 4, and the transmission device 10 receiving data called slave is in the state of online slave 5. When the mask passes the token to the downstream slave transmission device 10, the route is P4.
5. When the slave receives this, the confirmation route is P
It is u.

Next, the operation of returning from a state where loopback transmission is performed to a normal transmission state using only R times &111 by incorporating the separated portion will be described.

FIG. 5(a) shows an example of a state in which loopback transmission is performed.

(1)).

Figure 5(a) shows R line 11, or 5 times 1li1i11
In this example, there is an abnormality in the transmission device 2, and the transmission devices 5TNl and STN +1 are transmitting through a loop.

FIG. 5(b) is an example in which the transmission device 5TNj is disconnected due to a failure or the like, and the transmission devices 5TNj-1 and 5TNj+1 are respectively performing loopback transmission in the opposite direction.

FIGS. 6(a) and 6(b) are timing charts of data flowing through the transmission path when the line is tenuated.

Now, we will explain the re-incorporation operation in the case of Fig. 5(a) in Fig. 6.
This will be described with reference to Figures (a) and (b) ffi.

When the transmission device 5TN1 receives the token and enters the online master state 4, the disconnected time gt1.12
Check.

First, the transmission device STN□ is connected to the Lanut frame F1iR line 11'f! ! : Send to transmission device 8TN+1 in online slave state 5 via: If there is something wrong with the line,
The first part OMD'i acknowledgment (A
OK) F, and send it back via L line 12. If there is an abnormality in the R line 11 or L line 12, the transmission device 5T
Ni cannot receive the above frame F. At this time, it is assumed that there is no change in the state of the line, and loopback transmission continues, and if there is any data to be sent, it is sent.
Abandon the token and transition to online slave state 5. If an acknowledgment (AOK) frame F is returned as shown in FIG. 6(b), the transmission device BTN□.

It is assumed that the line between STN□+1 has returned to normal status. At this time, the first part of the transmission frame 13 is the line configuration (ONF), the second part SAi is 1011 for broad canute transmission, the third part PA is the address of the transmission device STN□, and the fifth part is the molecule ll1XT. It is transmitted via R all'e as line configuration data indicating a line state that allows normal transmission. After this data passes through Ike's transmission device,
Since the data enters the reception buffer 101 via the reception control circuit 103' (il-) shown in FIG. In this way, the loopback transmission device changes to the normal transmission state shown in FIG. 1(a).

Next, the case 21) in FIG. 5(b) will be described. The transmission device STN sends the test-1 frame F, i or F3 and the acknowledgment frame F, to the transmission device 5TNj.
Or receive F4. In the case of FIG. 6(a), loop push transmission is continued. In the case of FIG. 6(b), it is assumed that the line between the transmission device STN and the transmission devices 5TNj-1 and STNj has returned to the normal state.

At this time, as described above, the first
The part OMD is the line configuration (ONF), and the fifth part molecule EX
R line 11.
Transmit via 112i five times. As a result, the line state becomes -V as shown in FIG. 5(a).

Subsequently, the transmission device 5TNj transmits all transmission data, if any, and sends tokens to all downstream transmission devices BTNj, and transitions to online slave state 5. transmission device s
When T Nj receives the token, it checks the line between it and transmission device S T Nj+1, as shown in the case of FIG. 5(a). If the line is normal, after transmitting the frame shown in FIG. 6(b), the line returns to the state shown in FIG. 1(a).

〔Effect of the invention〕

Thus, according to the present invention, the line can be reconfigured smoothly and quickly without the need to specially provide a transmission device for supervisory control on the line.

[Brief explanation of drawings]

FIG. 1 is an overall block diagram when the transmission apparatus according to the present invention is connected, and FIG. 2 is a timing chart of data flowing through the transmission path. IO...Transmission device, 11...R line, 12...L
Line, 13... Transmission frame, 14... Failure occurrence part, 101... Reception buffer completed, 102... Transmission buffer, 103. 106.107...reception control circuit,
104.105. 108... Transmission control circuit, 109
...Selector switch. Applicant's agent Kiyoshi Inomata Figure 1 Figure 3 LINE Figure 5 (α)

Claims (1)

[Claims] 1. A token passing method in which a plurality of transmission devices are connected through a double loop transmission path and transmission rights are controlled by only the transmission device that holds one token in the system. In the transmission device, information that the transmission device or the transmission path can be transmitted normally is transmitted back through the double loop transmission path by disconnecting a part of the transmission device or the transmission path. A notification is sent to all transmission devices capable of transmitting the same data via one or two loop-shaped transmission lines to the transmission device that is currently disconnected from the transmission device that was previously disconnected, and the line is disconnected. A loop transmission device characterized in that it attempts to reconfigure. 2. The loop transmission device according to claim 1, wherein the transmission device capable of investigating the state of the adjacent separated portion is one of the transmission devices on both sides adjacent to the separated portion.