JPH03135122A - Degenerating operation system for optical bus network - Google Patents

Abstract

PURPOSE:To attain the communication between connection devices accommodated in a same optical transceiver even when a fault takes place in an optical transmission line by providing a transmission reception common bus and an optical bus fault detection section in the inside of the optical transceiver. CONSTITUTION:Any signal in connection devices 281,282,...28n is inputted also to drivers/receivers 271,272,...27n via a transmission reception common bus 40 and inputted to the 281,282,...28n while being subject to level conversion. An optical bus fault detection section 42 uses a carrier missing detection circuit 43 so as to check whether or not the carrier of a reception signal within a maximum delay time of an optical transmission line determined in the system and controls a switch circuit 44 when the carrier is not detected to disconnect an optical bus 10 from the transmission reception common bus 40. Through the constitution above, the inter-communication is attained without sending the signals of the connection devices 281,282,...28n to the optical transmission line and when a fault takes place in the optical transmission line, the affection of the fault of the optical transmission line onto the transmission reception common bus 40 is prevented.

Description

[Detailed Description of the Invention] (Summary) Regarding the improvement of optical transceivers used in U-shaped optical bus networks, even when a failure occurs on the optical transmission path, communication between terminals connected within the same optical transceiver is guaranteed. For the purpose of an optical bus network including a transceiver, a transmission/reception switching unit that provides a transmission/reception common bus as an internal bus of the optical transceiver and performs half-duplex communication control for transmission and reception between the transmission/reception common bus and the optical bus; The optical bus abnormality detecting section inspects whether a signal sent to the optical bus returns within a specified time, and performs control to disconnect the optical bus from the transmission/reception common bus in the event of an abnormality.

[Industrial application field]

The present invention is an optical CSMA/CD (Carrier
5ence MuItiple Access /C
Regarding the improvement of the optical transceiver used in the U-shaped optical bus network of the o11ision Detection) system, we have made it possible to guarantee communication between terminals connected within the same optical transceiver, especially when a failure occurs on the optical transmission path. This paper relates to a degenerate operation method for optical network networks.

FIG. 4 shows a U-shaped optical bus network of the optical C3MA/CD system, in which a large number of optical transceivers 11 . , 11□
, -, 11, are provided, and the transmitting no.
Optical bus 10 via 2+, 12□, -・-, 12,1
Connected to the upstream side of the receiving half mirror 13+, 13
By coupling to the downstream side of the optical bus 10 via the transceivers t,'-913, communication can be performed between the respective transceivers.

Each optical transceiver used in this case is IEEE8
A U that complies with the media access control regulations of 02.3
I (Attachment Unit Inte
rface) is configured to accommodate multiple connection devices by supporting multiple channels.
A plurality of connection devices arranged relatively close to the optical transceiver are housed in the same optical transceiver.

In such communication systems, when considering network applications, there is a case where there is more communication between adjacent connected devices accommodated in the same optical transceiver than there is communication between optical transceivers connected by optical transmission lines. There is.

Therefore, even if a failure such as a disconnection occurs in the optical transmission line, instead of the entire network system going down, it is possible to perform degenerate operation that can ensure local communication between connected devices housed in the same optical transceiver. It is requested that it be made possible.

[Conventional technology]

FIG. 5 is a block diagram showing a conventional optical transceiver, in which an optical transceiver 11 is connected via an optical bus 10, a half mirror 12 for transmission, and a half mirror 13 for reception.
It shows the internal configuration of.

The optical module 21 includes an optical/electrical (0/E) converter 22,
It has an electrical/optical (Elo) converter 23 that converts optical input and electrical output, or electrical input and optical output, respectively, and connects the optical bus 10 and the internal circuit of the optical transceiver 11. Electrical input/output of the optical module 21 is connected to a receiving bus 25 . via a common driver/receiver 24 . It is connected to the transmission bus 26. Furthermore, the receiving bus 25. From the transmission bus 26, the driver/receiver 27I, 27□, -・-, 27
, 1 to the connecting devices 281, 28□, . . . , 287.

Also, a transmission bus collision detection unit 29 that detects a collision in communication between each connected device on the transmission bus 26. An optical transfer path collision detection section 30 is provided that detects communication collisions on the optical transmission path, and a collision detection notification section 31 is provided that notifies the reception bus 25 of the collision detection results of each of these collision detection sections. .

The operation of the conventional optical transceiver shown in FIG. 5 during transmission is performed as follows.

Each connection device 28. , 28□, . ．． 27. ,...-
. . , 27□, level-converted, inputted to the common driver/receiver 24 via the transmission bus 26, level-converted, converted to an optical signal by the E10 converter 23 of the optical module 21, and sent to the optical bus 10. will be sent to. Transmission in this case is performed by each driver/receiver confirming that no other communication is occurring on the reception bus 25.

Further, the operation at the time of reception is performed as follows.

The optical signal from the optical transmission path is converted into an electrical signal by the O/E converter 22 of the optical module 21, level-converted via the common driver/receiver 24, and transmitted to the reception bus 25. The signal on the receiving bus 25 is further level-converted via driver/receivers 271.27□, -. ,28□,・-128□
transmitted to.

In this way, normally only one communication is carried out on the transmission bus and the optical bus, but if a plurality of transmissions happen to be carried out at the same time, a communication collision will occur.

Collision detection in this case is performed by the transmission bus collision detection unit 29. Collision detection is performed separately in the optical transfer path collision detection section 3°.

When a communication collision occurs on the transmission bus 26, the transmission bus collision detection section 29 detects it and immediately sends a collision notification to the reception bus 25 via the collision detection notification section 31. This sends a collision notification to each connected device that is transmitting, so each connected device stops transmitting and resumes transmitting after a waiting time determined by a random number, so the next transmissions will not occur at the same time. , transmission collisions are avoided.

Collisions on the optical transmission path are detected in the optical transmission path collision detection section 30 by storing the transmitted data in a memory at the time of transmission and comparing it with the received data returned from the optical transmission path. Even when a collision is detected by the optical transfer path collision detection unit 30,
A collision notification is sent to the reception bus 25 via the collision detection notification section 31.

[Problem to be solved by the invention]

In the conventional optical transceiver explained in FIG. 5, the transmitted data always passes through the optical transmission line, so if a failure occurs in the optical transmission line, even if the communication between connecting devices housed in the same optical transceiver is , there is a problem that communication becomes impossible.

The present invention is an attempt to solve the problems of the prior art as described above, and even if a failure occurs in the optical transmission line in an optical transceiver connected to a U-shaped optical bus network, the present invention can be accommodated in the same optical transceiver. The purpose of the present invention is to provide a degenerate operation method for an optical bus network that enables communication between connected devices.

[Means to solve the problem]

As shown in FIG. 1, the present invention connects an optical bus 10 to a large number of terminals 14 via an internal bus, and converts the internal bus into electrical signals and optical signals via a converter 15. In an optical bus network consisting of an optical transceiver 11 connected to the optical bus 10 by performing mutual conversion between the optical bus 10 and It is something.

Here, the transmission/reception common bus 40 is connected to this optical transceiver 11.
It is provided as an internal bus for the The transmission/reception switching unit 41 performs half-duplex communication control for transmission and reception between the transmission/reception common bus 4o and the optical bus 10, and the optical bus abnormality detection unit 42 detects whether the signal sent to the optical bus 1o is It checks whether it returns within a specified time or not, and controls to disconnect the optical bus 10 from the transmission/reception common bus 4o in the event of an abnormality.

[Effect]

To improve an optical transceiver used in a U-shaped optical bus network to enable communication between terminals connected within the same optical transceiver even when a failure occurs on an optical transmission path.

For this purpose, the optical bus IO is connected to a large number of terminals 14 via an internal bus, and the internal bus is mutually converted into an electrical signal and an optical signal via a converter 15.
In the optical transceiver 11 connected to the optical bus 0, a transmission/reception common bus 40 is provided as an internal bus of the transceiver, and a transmission/reception switching section 41 and an optical bus abnormality detection section 42 are provided so that the signal sent to the optical bus returns within a specified time. If there is an abnormality, the optical bus is disconnected from the internal bus.

In this way, since the transmission/reception common bus 40 is provided as an internal bus of the optical transceiver 11, it is possible to communicate with each other without sending the signals of each terminal to the optical transmission line, and the optical bus abnormality detection section 42 can be Since the optical transmission line is installed to detect failures such as disconnections on the optical transmission line and disconnect the optical transmission line if there is an abnormality, there is no risk that a failure on the optical transmission line will spread to the internal bus.

〔Example〕

FIG. 2 shows one embodiment of the present invention.
Components that are the same as in the figures are designated by the same numbers and their operations are also similar. On the other hand, the optical transceiver 11 has a common transmission/reception bus 40 for transmission and reception, and each terminal 14+, 14z, ~, 14a has a driver/receiver 271, 27! ,・−・−・.

271 and connecting device 28. ．． 28□, -.-128n.

Driver/Receiver 27. ．． 27□, -・-・, 27f
i are both connected to the transmission/reception common bus 40. The collision detection notification unit 31 notifies the transmission/reception common bus 40 of a collision based on the collision detected by the optical transfer path collision detection unit 30 .

Further, the transmission/reception switching unit 41 performs half-duplex communication control to switch transmission and reception between the transmission/reception common bus 40 and the optical bus 10. The optical bus abnormality detection section 42 includes a carrier loss detection circuit 43 and a switch circuit 44. The carrier loss detection circuit 43 connects the transmission/reception common bus 40 to the optical bus 10.
It is checked whether the carrier of the signal sent to can be detected within the viewing time after the signal is sent. Further, the switch circuit 44 is normally connected to the contact B side, and when the carrier disappearance detection circuit 43 detects carrier disappearance, switches the optical bus 10 to the A side.
is disconnected from the transmission/reception common bus 40.

In the embodiment shown in FIG. 2, the operation at the time of transmission is performed as follows.

Each connection device 28. , 23□, -, 28fi, which complies with the media access control regulations, is level-converted by the corresponding driver/receiver 271, 272°, 277, and sent to the transmit/receive common bus 4.
0, is sent out via contact B of the optical bus abnormality detection section 42 and contact A of the transmission/reception switching section 41, is converted into an optical signal by the E10 conversion section 23 of the optical module 21, and is transmitted to the optical bus 10 as an optical signal. and then sent to another optical transceiver.

On the other hand, each connection device 281, 281. . . -1287 is transmitted to each other driver/receiver 27 . ．． 27□,-・・-・, 27.
It is also input to L, and the level is converted to each connected device 2L, 2.
8z, ---128n. As a result, the connecting devices 2B, 28□, . . .

28.% can be directly transmitted to other connecting devices within the same optical transceiver 11.

In this case, signal collision on the transmit/receive common bus 40 is caused by each driver/receiver 27 . ．． 27t. , 28□, . . . , 287 are notified.

Next, the operation at the time of reception is performed as follows.

Optical signals from other optical transceivers in the optical bus 10 are converted into electrical signals by the O/E converter 22 of the optical module 2, and the B contacts of the transmission/reception switching unit 41 and the B contact of the optical bus abnormality detection unit 42 are converted to electrical signals. It is transmitted to the transmission/reception common bus 40 via the driver/receiver 271.27□, -, 2
The level is converted through 7, and each connected device 2B+, 28
□, -・-・, is input to 28fi.

Collision detection on the optical transmission path is carried out in the optical transmission path collision detection section 30, as in the past, by storing the transmitted signal in memory at the time of transmission and comparing it with the signal that has returned along the optical transmission path. If detected, the collision detection notification unit 3
1, the transmission/reception common bus 40 is notified.

In addition, in the optical bus abnormality detection unit 42, when the carrier loss detection circuit 43 does not detect the carrier of the received signal within the visual time after the signal is sent from the transmission/reception common bus 40 to the optical bus 10, the switch circuit 44 , disconnects the optical bus 10 from the transmission/reception common bus 40. As the standard time in this case, for example, the maximum delay time of the optical transmission path determined by the system is selected.

FIGS. 3(a) and 3(b) are diagrams showing the configuration and operation of the optical bus abnormality detection section 42, in which (a) is a block diagram showing the configuration, and (b) is a time diagram showing the operation. It is a chart.

When there is no abnormality in the optical bus 10, the switch circuit 44 is connected to the contact B side, and the transmission/reception common bus 40 is connected to the contact B side.
The transmission signal shown in (■) is sent to the optical bus 10 via the transmission/reception switching section 41 and the optical module 21.

The optical bus 10 is U-shaped, and the optical transfer path delay time t
After d, the received signal carrier shown in ■ is detected.

However, if an abnormality such as a disconnection occurs in the optical bus 10,
The carrier of the received signal is not detected. The carrier loss detection circuit 43 checks whether the carrier of the received signal is detected within the maximum delay time te of the optical transmission path defined by the system, and when the carrier is not detected within the time te, By controlling the switch circuit 44 to switch to the contact A side, control is performed to disconnect the optical bus 10 from the common transmission/reception bus 40.

Therefore, in this state, signals from other optical transceivers are cut off and transmitted to each terminal 141, 142, .
Communication can be performed between 47.

〔Effect of the invention〕

As explained above, according to the present invention, since the transmission/reception common bus and the optical bus abnormality detection section are provided inside the optical transceiver, transmission and reception can be performed between each terminal connected within the same optical transceiver without going through an optical transmission line. They can communicate with each other via a common bus, and even if a failure occurs in the optical transmission path, communication can be guaranteed between connecting devices housed in the same optical transceiver.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the basic configuration of the present invention, FIG. 2 is a diagram showing an embodiment of the present invention, and FIGS. 3(a) and 3(b) are diagrams showing the configuration and operation of the optical bus abnormality detection section. The figure shown in Fig. 4 is an optical CS.
A diagram showing an MA/CD type U-shaped optical bus network,
FIG. 5 is a block diagram showing a conventional optical transceiver. 10 is an optical system, 11 is an optical transceiver, 14 is a terminal, 1
5 is a converter, 40 is a transmission/reception common bus, 41 is a transmission/reception switching unit, and 42 is an optical bus abnormality detection unit.

Claims (1)

[Claims] A large number of terminals (14) are connected via an optical bus (10) and an internal bus.
) and an optical transceiver (11) that connects the internal bus to the optical bus (10) by mutually converting the internal bus into an electrical signal and an optical signal via a converter (15). In the optical transceiver (11
) is provided with a common transmission/reception bus (40) as an internal bus of the optical bus (10), and a transmission/reception switching unit (41) that performs half-duplex control of transmission and reception between the common transmission and reception bus (40) and the optical bus (10).
Then, it is checked whether the signal sent to the optical bus (10) returns within a specified time, and in case of an abnormality, the transmission/reception common bus (40) is checked.
) A degenerate operation method for an optical bus network, characterized in that an optical bus abnormality detection unit (42) is provided to perform control to disconnect the optical bus (10) from the optical bus (10).